JP2016031281A - Weighing device and article conveying system - Google Patents

Abstract

Even when an article is continuously conveyed, zero adjustment can be performed without causing the article to stay.
A weight sorter provided on a transport line for transporting an article G and having a weighing conveyor 7 for weighing the article G while transporting the article G, and a weight without changing the transport speed of the article G by the transport line. And a pusher 9 as an interval changing means for changing the conveyance interval of the articles G carried into the sorter 4, and the weight sorter 4 has a no-load state in which no articles G exist on the weighing conveyor 7. The pusher 9 is controlled to perform zero point adjustment.
[Selection] Figure 1

Description

  The present invention relates to a weighing device for weighing an article while conveying the article, and an article conveying system including the weighing apparatus.

  This type of weighing device, for example, a weight sorter, weighs articles while being conveyed by a weighing conveyor, and sorts and sorts articles on the downstream side of the weighing conveyor according to the weight of the weighed articles.

  In such a weight sorter, even if the load sensor supporting the weighing conveyor is normal, the surrounding temperature may change due to minute changes in temperature and humidity. The zero point weight value of the weighing conveyor, that is, the weight measurement value when no article is present on the weighing conveyor, changes gradually to a non-negligible magnitude with the passage of the operation time of the weight sorter. Occurs.

  Therefore, in order to measure the weight of the article with high accuracy, it is necessary to correct the zero point fluctuation by performing zero point adjustment.

  In order to ensure weighing accuracy, it is not possible to increase the conveyance speed in order to weight-sort articles on a conveyance line equipped with a production device with a large production quantity per unit time, so the articles are continuously conveyed at short intervals and weighed. It is fed onto the conveyor. To adjust the zero point, it is necessary to measure the zero point weight value, which is the weight value in an unloaded state where no article is present on the weighing conveyor, but the preceding article whose weight has been measured on the weighing conveyor is removed from the weighing conveyor. Prior to unloading, subsequent articles are loaded into the weighing conveyor, so that the articles are continuously loaded into the weighing conveyor without any interruption. The zero value cannot be adjusted by measuring the weight value.

  For this reason, for example, in Patent Document 1, the preceding conveyor of the weighing conveyor (weighing conveyor) is temporarily stopped, or the conveyance speed is lowered to force a no-load state (empty state) where no article exists on the weighing conveyor. It is described that the zero point adjustment is performed by appearing automatically. In addition, this no-load state is forced to appear when the article is supplied to the weighing conveyor without interruption for a predetermined time or more.

Japanese Utility Model Publication No. 3-32985

  However, as shown in Patent Document 1, if the conveyor at the front stage of the weighing conveyor is stopped or the conveyance speed is lowered in order to make the unloaded state appear, the articles from the production apparatus are placed on the conveyor at the front stage of the weighing conveyor. It will stay and the staying article must be processed. Moreover, after the zero point adjustment of the weighing conveyor is completed, the returning operation until the article is returned to the original conveying speed is also troublesome.

  Furthermore, the zero point fluctuation speed of the weight sorter changes depending on the ambient temperature change and the condition of the deposits on the weighing conveyor during operation. When the zero point adjustment is performed every predetermined time, the zero point fluctuation speed is the highest. Must be set for a large period of time, and wasteful work is generated in a period where the zero point fluctuation speed is small. At the same time, the weighing capacity is reduced.

  The present invention has been made in view of the above points, and it is possible to perform zero point adjustment without retaining an article even when the article is continuously conveyed. Objective.

  In order to achieve the above object, the present invention is configured as follows.

(1) The article transport system of the present invention is provided in a transport line for transporting articles, and has a weighing device for weighing the articles while transporting the articles, without changing the transport speed of the articles by the transport lines. And a conveyance interval changing means for increasing the conveyance interval of the article,
The weighing device has a control unit that controls the conveyance interval changing unit, a no-load state detection unit that detects a no-load state in which no article exists on the weighing conveyor, and when the no-load state is detected, A zero point adjustment unit that measures the zero point weight value of the weighing conveyor and adjusts the zero point,
The control unit of the weighing device controls the conveyance interval changing unit so that the no-load state occurs.

  The conveyance interval changing means increases the conveyance interval of the articles without changing the conveyance speed of the articles by the conveyance line, for example, by removing the articles on the conveyance line.

  According to the article conveyance system of the present invention, the weighing device controls the conveyance interval changing means, thereby increasing the article conveyance interval without changing the article conveyance speed by the conveyance line, and placing the article on the weighing conveyor. Therefore, the zero point adjustment can be performed without stopping the transport line or reducing the transport speed. Thus, since the zero point adjustment is not required, it is not necessary to stop the conveyance line or decrease the conveyance speed, so that the zero point adjustment can be easily performed without causing the article to stay.

  (2) In a preferred embodiment of the article transport system of the present invention, the control unit of the weighing device controls the transport interval changing unit to vary the time interval for causing the no-load state.

  According to this embodiment, the weighing device controls the conveyance interval changing means to generate a no-load state in which no article is present on the weighing conveyor, that is, a time interval for performing zero adjustment in the no-load state. For example, it is possible to arbitrarily change the zero adjustment interval according to the operation status of the weighing device, etc., and unnecessary post-processing work occurs without unnecessarily degrading the weighing processing capacity. You don't have to.

  (3) In another embodiment of the article transport system of the present invention, the control unit of the weighing device can vary the time interval for causing the no-load state in accordance with an elapsed time from a preset time point. To do.

  According to this embodiment, the time interval for causing the no-load state is varied according to the preset time point, for example, the elapsed time from the start time of the operation of the weighing device. During periods when the zero point fluctuation amount is relatively short and the ambient temperature such as air conditioning temperature is stable, the time interval for zero adjustment is shortened, the elapsed time from the start of operation is relatively long, and the zero point fluctuation amount is small and stable. During this period, it is possible to increase the time interval for performing the zero adjustment, so that the measurement processing capacity is not unnecessarily lowered and no extra post-processing work is required.

  (4) In still another embodiment of the article transport system of the present invention, the control unit of the weighing device varies the time interval causing the no-load state according to a zero point fluctuation speed of the weighing device. .

  According to this embodiment, since the time interval for generating the no-load state is varied according to the zero point fluctuation speed, when the zero point fluctuation speed is large, the time interval for generating the no load state, that is, zero adjustment is performed. When the time interval is shortened and the zero point fluctuation speed is small, the time interval for performing the zero point adjustment can be lengthened. As a result, the time interval for performing the zero adjustment is too long, the amount of fluctuation in the zero point is increased, the measurement accuracy of the weight value of the article is lowered, and conversely, the time interval for performing the zero adjustment is too short, Will not be unnecessarily large, and there will be no increase in the work of reweighing them later or the weighing capacity will not be reduced.

  (5) In an embodiment of the article transport system according to the present invention, the control unit of the weighing device determines the time interval causing the no-load state based on a weight value of the article to be weighed by the weighing conveyor. Variable.

  According to this embodiment, based on the weight value of the article to be weighed, for example, when the weight value of the article shows a gradual fluctuation that tends to increase or decrease as a whole, although it varies, The time interval for causing the no-load state is changed so that the zero point adjustment can be performed if the zero point fluctuation occurs.

  (6) In another embodiment of the article conveyance system of the present invention, the conveyance interval changing means is an article removal device that removes the article from the conveyance line to increase the article conveyance interval.

  According to this embodiment, since the conveyance interval changing unit removes the article to be conveyed from the conveyance line, it is possible to increase the conveyance interval of the article without changing the conveyance speed of the article by the conveyance line. is there.

  (7) In another embodiment of the article transport system of the present invention, the transport interval changing means is a production apparatus that continuously produces the article and sends it to the transport line, and temporarily produces the article. To stop the article and increase the conveyance interval of the article.

  According to this embodiment, the conveyance interval changing means temporarily stops the production of the articles to be sent to the conveyance line, and changes the conveyance speed of the articles by the conveyance line by not producing one or a plurality of articles. Without this, the conveyance interval of the articles can be increased.

(8) The weighing device of the present invention is a weighing device that is provided in a conveyance line for conveying an article and has a weighing conveyor for weighing while conveying the article,
A control unit that controls a conveyance interval changing unit that increases the conveyance interval of the article without changing the conveyance speed of the article by the conveyance line, and no load that detects a no-load state in which no article exists on the weighing conveyor A state detection unit, and a zero point adjustment unit that measures the zero point weight value of the weighing conveyor and performs zero point adjustment when the no-load state is detected,
The control unit of the weighing device controls the conveyance interval changing unit so that the no-load state occurs.

  According to the weighing device of the present invention, by controlling the conveyance interval changing means, the article conveyance interval is increased without changing the article conveyance speed by the conveyance line, so that no article is present on the weighing conveyor. Since the state can be set, the zero point adjustment can be performed without stopping the transport line or reducing the transport speed. In order to perform zero point adjustment in this way, it is not necessary to stop the conveyance line or reduce the conveyance speed, so that it is easy to cause the operation of reweighing the retained article by retaining the article. Zero point adjustment can be performed.

  According to the present invention, the weighing device controls the conveyance interval changing unit to increase the article conveyance interval without changing the article conveyance speed by the conveyance line, so that no article exists on the weighing conveyor. Since it can be in a load state, the zero point adjustment can be performed without stopping the transport line or reducing the transport speed. Thus, since the zero point adjustment is not required, it is not necessary to stop the conveyance line or decrease the conveyance speed, so that the zero point adjustment can be easily performed without causing the article to stay.

FIG. 1 is a diagram showing an article transport system including a weighing device according to an embodiment of the present invention, (a) is a schematic configuration diagram thereof, and (b) is a schematic plan view of a main part. FIG. 2 is a diagram for explaining the timing of the measurement of the article weight and the zero point weight value, (a) is a schematic configuration diagram corresponding to FIG. 1 (a), and (b) is a weighing conveyor. 7 is a diagram showing a load distribution of 7. FIG. FIG. 3 is a block diagram of a main part of the control device of FIG. FIG. 4 is a flowchart showing the process of measuring the weight of an article. FIG. 5 is a flowchart showing the zero point measurement processing subsequent to FIG. FIG. 6 is a flowchart showing processing for determining the operation timing of the pusher 9 subsequent to FIG. FIG. 7 is a flowchart showing the driving process of the pusher 9 subsequent to FIG. FIG. 8 is a diagram for explaining the timing from the detection of an article to the measurement of the article weight value and the measurement of the zero point weight value. FIG. 9 is a flowchart showing processing such as calculation of an article weight value. FIG. 10 is a flowchart showing processing such as calculation of the zero point weight value. FIG. 11 is a flowchart showing processing such as calculation of an article weight value according to another embodiment of the present invention. FIG. 12 is a flowchart showing processing such as calculation of a zero point weight value according to another embodiment of the present invention. FIG. 13 is a schematic configuration diagram corresponding to FIG. 1A of another embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
[Schematic configuration of article transport system]
FIG. 1 is a diagram illustrating an article transport system including a weight sorter as a weighing device according to an embodiment of the present invention, in which FIG. 1 (a) is a schematic configuration diagram thereof, and FIG. It is a schematic plan view of the principal part.

  The article transport system of this embodiment includes a product production device 3 including a capacity type filling device 1 and a packaging device 2, and an article G as a product unloaded from the product production device 3 is a transport line. The weight is measured by the weight sorter 4 installed on the downstream side in the transport direction (right direction in the figure), and is sorted into a non-defective product and a defective product by a sorting device (not shown). In the product production device 3, the raw material is filled into the container by a predetermined volume by the filling device 1, and the container filled with the raw material is packaged in the form of the product by the subsequent packaging device 2 and sequentially carried out as an article G. . The unloaded article G is conveyed by the conveyor 5 at a predetermined interval L1. The product production device 3 may be a combination weigher that replaces the filling device 1 and discharges the products in a predetermined weight range by combination weighing.

  The weight sorter 4 includes a feeding conveyor 6 that feeds an article G from a conveyor 5 constituting a conveying line of the article G to a weighing conveyor 7, and the weighing conveyor 7 supported by a load sensor 10 including a load cell. Then, based on the load conveyor 8 that carries the article G from the weighing conveyor 7 to a sorting device (not shown) and the load signal from the load sensor 10, the weight and zero point weight value of the article G are measured as described later. And a control device 11 for performing the above operation. The control device 11 measures the weight of the article G conveyed by the weighing conveyor 7 and controls the distribution device, thereby allowing an appropriate amount product within a predetermined range, a lightweight product less than the predetermined range, and a predetermined range. Sort and sort oversized items that exceed.

  In the weight sorter 4, in order to measure the weight of the article G, only the article G to be measured exists on the weighing conveyor 7 and the load signal from the load sensor 10 is stabilized for a certain period of time. It is necessary to secure.

  In addition, in order to measure the weight of an article with high accuracy in the weight sorter 4, the zero point fluctuation caused by changes in ambient temperature or humidity, application of excessive load to the weighing conveyor 7, or deposits. Needs to be corrected by zero adjustment. In order to perform zero point adjustment, it is necessary to measure a zero point weight value that is a weight value in an unloaded state in which no article exists on the weighing conveyor 7, and an unloaded state in which the article G does not exist on the weighing conveyor 7, It is necessary to secure a certain period.

  Here, the timing of the measurement of the weight of the article G and the measurement of the zero point weight value will be described with reference to FIG.

  Fig.2 (a) is a schematic block diagram corresponding to Fig.1 (a), FIG.2 (b) is a figure which shows load distribution of the measurement conveyor 7 of Fig.2 (a). 2, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and peripheral articles G including the weighing conveyor 7 are denoted by auxiliary numbers (0 to 3) in the order of conveyance.

  When the production amount of the goods G carried out from the product production apparatus 3, for example, the maximum production number of the goods G per minute is A (pieces / minute), the weighing conveyor 7 and the conveyors 6 and 8 before and after the weighing conveyor 7. If the conveyance speed of the conveyance line that conveys the article G including V is V (m / min), the conveyance interval L1 of the article G to be conveyed, that is, the distance L1 from the leading edge of the preceding article to the leading edge of the subsequent article Is L1 = V / A (m). The length of the weighing conveyor 7 in the article conveyance direction is set to approximately L1 so that the weight of the article G can be measured even in the case of the maximum production number.

  In order to measure the weight of the article G present on the weighing conveyor 7, a certain period or more is ensured during which only the article G to be measured exists on the weighing conveyor 7 in order to obtain a stable load signal. There is a need to.

  If the length along the conveyance direction of the article G is L2 (L2 <L1), even if the article G is continuously carried into the weighing conveyor 7 at an interval of L1, one article G on the weighing conveyor 7 ( In the period of (L1-L2) / V (minutes), since only the article G exists on the weighing conveyor 7 during the movement of the distance L1-L2), the weight of the article G in this period. Can be measured.

  On the contrary, when the zero point weight value of the weighing conveyor 7 is measured and the zero point adjustment is performed, it is necessary to ensure a no-load state where the article G is not on the weighing conveyor 7 for a certain period of time.

  The trapezoidal solid line in FIG. 2 (b) is shown on the weighing conveyor 7 by the article G1 in FIG. 2 (a) under the conditions such as the production number A (pieces / minute) and the conveyance speed V (m / minute). The one-dot chain line is the load distribution due to the preceding article G0, and the broken line is the load distribution due to the subsequent article G2. In FIG. 2 (b), the load of the weighing conveyor 7 is the period (L1-L2) / V (minutes) corresponding to the length of (L1-L2) due to the article G1 only. The weight of the article G1 is measured.

  In FIG. 2, if the article G1 does not exist, the period (L1-L2) / V (minutes) corresponding to the length of (L1-L2) is a period in which there is no article on the weighing conveyor 7. That is, it becomes a period in which the zero point weight value can be measured.

  Further, if the production capacity of the product production apparatus 3 is reduced and the production line in FIG. 2A is used, the production capacity is reduced to, for example, 1/2, that is, the number of articles G produced per minute is A / 2. In the case of (pieces / minute), in the conveyance of the articles G0, G1, and G2, it is the same as the absence of the article G1 from the beginning. Therefore, for each article, the period when there is no article G on the weighing conveyor 7 When (L1-L2) / V (minutes) is generated and the weight of one article is measured, the zero point weight value can be measured and the zero point can be adjusted. That is, when the production capacity is set to A / 2 (pieces / minute) or less, every time the weight of one article G is measured, an opportunity to adjust the zero point by measuring the zero point weight value can be obtained.

  However, since the production capacity of the commodity production apparatus 3 has a high value in a normal case, for example, the production number of articles G per minute is produced at A (pieces / minute) as described above, and downstream The article G is carried out to the transport line. In this case, the articles G are continuously carried into the weighing conveyor 7 without interruption, and the weight thereof is measured, and there is no period in which the articles G do not exist on the weighing conveyor 7.

  Therefore, in order to measure the weight of an article with high accuracy, if zero adjustment is performed at a necessary time interval, it is necessary to forcibly generate a period in which the article G does not arrive on the weighing conveyor 7.

  In Patent Document 1, a predetermined period is set, and when the article G is not interrupted during the predetermined period and the zero point adjustment of the weight sorter 4 cannot be performed, the motor of the conveyor preceding the weighing conveyor is stopped or slowed down. Thus, the conveyance interval of the articles is increased, a no-load period in which no articles exist on the weighing conveyor is forcibly generated, and the zero point weight value is measured to perform the zero point adjustment.

  However, as shown in FIG. 2A, when each article G is continuously carried into the weighing conveyor 7 at a conveyance interval of L1, for example, a certain article G is conveyed in order to perform zero adjustment. When stopping on the line or reducing the conveying speed, the interval between the articles immediately approaches an interval shorter than L1, and the interval at which the article G can be measured based on a stable load signal (L1-L2) Cannot be maintained, and two or more articles G are carried onto the weighing conveyor 7, causing a serious trouble.

  Therefore, in the present embodiment shown in FIG. 1, at the timing when the zero point adjustment is necessary in the weight sorter 4, so as not to disturb the conveyance interval of the articles G on the conveyance line preceding the weighing conveyor 7, that is, the weighing conveyor. The period during which the weighing conveyor 7 is in a no-load state is generated without changing the conveying speed of the preceding conveying line 7.

  Specifically, the article G is transferred as a transfer interval changing means for increasing the transfer interval of the article G carried into the weighing conveyor 7 of the weight sorter 4 without changing the transfer speed of the article G by the transfer line. The article removing device for removing the outside is installed in the transport line in the previous stage of the weighing conveyor 7, and one or a plurality of preset articles G transported on the transport line are brought into the transport state of the articles G before and after that. I try to remove it without affecting it.

  As this article removal apparatus, for example, a pusher that pushes the article G out of the conveyance line by a pressing plate that moves in a direction perpendicular to the conveyance line, and an article G is conveyed by discharging air in a direction perpendicular to the conveyance line. An air jet that blows off the line, or a sorting device such as a flipper that guides the article G to the outside of the conveyance line by blocking the article conveyance line for a predetermined period can be used. This article removal device is provided in the transport line in the previous stage of the weighing conveyor 7 of the weight sorter 4.

  Depending on the drive signal from the control device 11 of the weight sorter 4, the reciprocating operation is performed a set number of times for a pusher, and the discharging operation is set a set number of times for an air jet, for a required time interval. Only the set number of articles G are removed from the transfer line by operating the transfer line to be cut off for a set time.

  In this embodiment, as shown in FIG. 1, the pusher 9 is used in the width direction of the feed conveyor 6 as an article removing device that removes a predetermined one or a plurality of continuous articles G from the conveying line of the article G. It is installed on one side.

  The control device 11 measures the weight of the article G carried on the weighing conveyor 7 based on the load signal from the load sensor 10 that supports the weighing conveyor 7, and the article G exists in the weighing conveyor 7. A no-load state is detected, a zero-point weight value that is a weight value in the no-load state is measured, and zero adjustment is performed.

  A first article detection sensor 12 made of, for example, a photosensor is installed between the feeding conveyor 6 and the weighing conveyor 7, and the first article detection sensor 12 detects the article G just before being carried into the weighing conveyor 7. Detect.

  The pusher 9 as the article removing device is installed on one side in the width direction of the feeding conveyor 6 as described above, and the pusher 9 is operated at an appropriate timing with respect to the article G to be removed. In addition, a second article detection sensor 13 made of, for example, a photo sensor is installed to detect the article G arriving at a predetermined position of the feeding conveyor 6.

  When the article arrives in the detection area of the second article detection sensor 13, if it is time to perform zero point adjustment, the pusher 9 is driven to reciprocate by the drive signal from the control device 11, and the width of the feeding conveyor 6 is reached. Only one article to be removed is distributed to the removed article storage box 14 arranged on the other side in the direction. Alternatively, if, for example, two articles are set as the number of articles G to be removed, the pusher 9 is also applied to the article G detected by the second article detection sensor 13 next to the previously removed article G. Are reciprocated to remove two articles G in succession. Thereby, it is possible to maintain a sufficiently long period of no-load state for performing zero point adjustment in which no article exists on the weighing conveyor 7.

  Further, in this embodiment, since it is necessary to adjust the zero point of the weight sorter 4, the time interval for outputting the drive signal to the pusher 9 to remove the article, that is, the time interval for performing the zero point adjustment will be described later. Furthermore, the time interval is controlled according to the magnitude of the zero point fluctuation speed of the weight sorter 4.

  That is, the zero point fluctuation speed of the weight sorter 4 is detected, and when the zero point fluctuation speed is large, the time interval for performing the zero point adjustment is shortened, and when the zero point fluctuation speed is small, the time interval for performing the zero point adjustment is lengthened. To do.

  As described above, the pusher 9 is operated at a time interval corresponding to the magnitude of the zero point fluctuation speed of the weight sorter 4 to remove the article and adjust the zero point. Therefore, the zero point adjustment is performed at an unnecessarily short time interval. It is possible to avoid a situation in which the weighing accuracy is lowered or the zero point adjustment is performed at a long time interval and the weighing accuracy is lowered due to a large fluctuation of the zero point.

[Configuration of weight sorter 4]
FIG. 3 is a block diagram of a main part in the control device 11 of the weight sorter 4, and parts corresponding to those in FIG. 1 are denoted by the same reference numerals.

  The control device 11 amplifies the analog load signal from the load sensor 10 and removes a high frequency component, an A / D converter 16 that converts the load signal from the amplifier 15 into a digital signal, A control unit 17 that performs a filter process for attenuating vibration noise and the like included in the load signal from the D converter 16 to calculate the weight value of the article and the like, and controls each part including the pusher 9; An input unit 18 having operation keys operated for setting and the like, and a display unit 19 for displaying measurement results and the like are provided. You may comprise the input part 18 and the display part 19 with the touchscreen which integrated them.

  The control unit 17 includes a CPU, a memory in which data such as a control program and weight values are stored, an input / output circuit, and the like, and various timer counter functions described later.

  In addition to the filtering process described above, the control unit 17 calculates the zero point weight value and adjusts the zero point based on the filtered load signal when there is no article on the weighing conveyor 7 to adjust the zero point. When an article is on the top, it performs various arithmetic processes such as calculating the weight value of the article, and has a function as a zero point adjustment unit that performs zero adjustment.

  The control unit 17 is supplied with detection outputs of the first and second article detection sensors 12 and 13 and controls the drive of the pusher 9 for removing the article. The control unit 17 has a function as a no-load state detection unit that detects a no-load state where there is no article on the weighing conveyor 7 based on the output of the first article detection sensor 12.

[Unloading period and zero adjustment of weighing conveyor 7]
Next, a description will be given of a period of no load in which no article is present on the weighing conveyor 7 and zero point adjustment performed during that period.

  Articles carried into the weighing conveyor 7 are removed out of the conveying line by a pusher 9 which is an article removing device, causing a no-load period in which no articles exist on the weighing conveyor 7, and in this no-load condition period Then, the zero point weight value is measured to adjust the zero point.

  Here, the zero point weight value and zero point adjustment will be described.

If K is a span coefficient, Wad is an output value of a filter for filtering a digital load signal output from the A / D converter 16, Wi is a tare weight of the weighing conveyor 7, and WZ is an accumulated zero point variation, the weighing conveyor 7 The weight measurement Wn of the above article is
Wn = K · (Wad−Wi) −WZ (1)
It is expressed.

  The weight measurement value Wn obtained based on the digital load signal Wad when the article is present on the weighing conveyor 7 is the weight value of the article.

  The weight measurement value Wn obtained based on the digital load signal Wad when no article is present on the weighing conveyor 7 is the zero point weight value.

What is zero adjustment?
Wn + WZ → WZ
That is, the operation of adding the accumulated zero point fluctuation amount WZ so far to the newly measured zero point weight value Wn to obtain a new accumulated zero point fluctuation amount WZ.

  For example, even when the weighing conveyor 7 is in a no-load state, when Wn ≠ 0 and Wn = wd, for example, by performing zero adjustment, Wn + WZ = wd + WZ → WZ is calculated. Then, the accumulated zero point fluctuation amount WZ increases by wd from the above, and the weight measurement value Wn = 0 is adjusted from the above equation (1), and the weight value of the article after that is zero after the zero point adjustment. The quantity is calculated by the above equation (1).

  Even if an article is removed by the pusher 9 which is an article removing device, and the preceding article is unloaded from the weighing conveyor 7, an unloaded condition in which the article is not carried into the weighing conveyor 7 is caused. If a large vibration signal, i.e., a transient response signal, is left when being carried out of the conveyor 7, the measured zero-point weight value Wn has a large amount of variation. In this way, when the zero point weight value Wn varies, if the zero point weight value Wn that is not accurate is added to the accumulated zero point fluctuation amount WZ by performing zero point adjustment, the subsequent zero point weight value WZ is used using the inaccurate accumulated zero point fluctuation amount WZ. The weight value of the article will be calculated, and the weight value of the article will be inaccurate.

  The transient response vibration signal when the article is carried out from the weighing conveyor 7 is attenuated by the filter, but the filter output is not responding if sufficient time has not passed since the article was carried out from the weighing conveyor 7. Or it may not be smooth. For this reason, depending on the specifications, it is necessary to leave the weighing conveyor 7 in an unloaded state only for a time necessary for the zero point weight value to be sufficiently stabilized. Therefore, the pusher 9 is actuated a predetermined number of times by operating the input unit 18 and a preset value set in advance to remove one or a plurality of articles as described above.

  For example, in FIG. 2, if only one article G1 is removed, the load distribution of the article G1 in FIG. 2 disappears, and the longest 60 · () from the time point a when the preceding article G0 is unloaded from the weighing conveyor 7. L1−L2) / V (seconds) until no point b, but in the measurement of this point b, if the variation of the zero point weight value is still large, two as the number of articles removed in advance, It is set in the input unit 18 and the article G2 is subsequently removed after the article G1 so that the zero point weight value can be measured in the period from the longest point to the points a to c.

[Zero adjustment time interval according to zero fluctuation speed]
Next, the time interval for adjusting the zero point by operating the pusher 9 will be described. In this embodiment, as described above, the zero point adjustment is performed at time intervals corresponding to the fluctuation speed of the zero point fluctuation amount of the weight sorter 4.

  That is, according to the zero point fluctuation speed of the weight sorter 4, the time interval for operating the pusher 9 is controlled so as to control the time interval for adjusting the zero point.

  For example, it is assumed that the zero point fluctuation amount is allowed up to 0.2 g (zero point fluctuation allowable amount) according to the specification, and the time interval for operating the pusher 9 is set to 0.5 hours (reference interval) as a default value. .

  In the present embodiment, the time interval for operating the pusher 9 is determined by the number of articles whose weights are measured, that is, the number of times NCx is measured, because the measurement of the article weight is performed at a constant time interval. Yes.

  At some point, the pusher 9 is actuated to put the weighing conveyor 7 in an unloaded state, one article flowing through the transfer line is removed, and the unloaded weight without an article on the weighing conveyor 7 of the weight sorter 4 The first zero point weight value Wn = Z (n + 1) is measured and stored as the first zero point weight value Z (n + 1), and then the first zero point adjustment is performed using the zero point weight value. Suppose. That is, Wn = 0.

  After the first zero adjustment, the time interval until the next zero adjustment is performed. The time interval until the next time the pusher 9 is actuated is counted as described above. When the time interval Tx = 0.5 hours, which is the default value, is counted, the pusher 9 is operated to generate a no-load state, and the zero point weight value Wn = Z (n + 1) is measured.

With respect to the zero point weight value Wn = 0 after the previous zero point adjustment, which is the first time, the zero point weight value Wn before the second zero point adjustment, which is the second time,
If | Wn | = | Z (n + 1) | = 0.1 g, there was a zero-point fluctuation of 0.1 g during 0.5 hours from the first time to the second time.

Therefore, the zero point fluctuation speed between the first time and the second time is | Z (n + 1) | /Tx=0.1/0.5.
= 1/5 = 0.2 (g / h).

Therefore, at this zero point fluctuation speed, the time to reach the zero point fluctuation allowable amount of 0.2 g is calculated as 0.2 / 0.2 = 1.0 hour, and then the pusher 9 is operated until the zero point adjustment is performed. The time interval is within 1.0 hour from the current operation timing, for example, 1.0 hour later. In this case, since the zero point fluctuation speed is relatively slow, the time interval for performing the zero point adjustment by removing the article is lengthened.

On the other hand, with respect to the zero point weight value Wn = 0 after the previous zero point adjustment, which is the first time, the zero point weight value Wn before the second zero point adjustment, which is the second time,
If | Wn | = | Z (n + 1) | = 0.3 g and there is 0.3 g of zero point fluctuation during the 0.5 hour from the first time to the second time, the zero point fluctuation speed during this period is | Z (n + 1) | /Tx=0.3/0.5=0.6 (g / h).

Therefore, at this zero point fluctuation speed, the time to reach the zero point fluctuation allowable amount of 0.2 g is
It is calculated that 0.2 / 0.6 = 0.33 hours, and the time interval until the pusher 9 is operated next is within 0.33 hours from the current operation timing, for example, 0.33 hours later. In this case, since the zero point fluctuation speed is relatively fast, the time interval for performing the zero point adjustment by removing the article is shortened.

  Upper and lower saturation values are provided for this time interval. If the time interval smaller than the lower limit saturation value TL is calculated because the zero point fluctuation speed is large, the time interval is larger than the upper limit saturation value TU because the zero point fluctuation speed is limited. If this happens, the upper limit saturation value TU is limited.

  Coincidentally, due to the convenience of the product production apparatus 3 and the conveyance line in the middle, the article may be interrupted until the next time interval for operating the pusher 9, and the time interval calculated during the previous zero adjustment When the load on the weighing conveyor 7 becomes unloaded at a short time interval, that is, at an early time point, zero adjustment is performed, the zero weight value is measured as Z (n), and the previous memory is updated and stored. Next, the time interval for operating the pusher 9 is not recalculated, and the time interval is measured again from this time point to the previously calculated time interval.

  However, at this time, if the time interval is longer than a certain value from the previous zero adjustment, the zero weight value at this time is set to Z (n + 1), and the zero weight value Z stored at the previous zero adjustment is stored. According to (n), the time interval for operating the pusher 9 next may be newly calculated according to the zero point fluctuation speed as described above.

  Thus, every time zero adjustment is performed, the time interval at which zero adjustment is performed, that is, the time interval at which the pusher 9 is operated, is controlled so as to prevent fluctuations up to the zero fluctuation allowable amount while measuring the zero fluctuation speed. Therefore, it is possible to avoid a situation where zero adjustment is performed at an unnecessarily short time interval, or conversely, zero adjustment is not performed even though the zero fluctuation amount is large.

  When the time interval for operating the pusher 9 is set as the count value of the number of times of measurement of the article weight value, the measurement number Cx of the article weight value is Cx / Corresponds to A (minutes).

  As another embodiment of the present invention, the time interval may be directly counted by a time counter provided in the arithmetic circuit of the control unit 17 instead of counting the number of measurements of the article weight value.

[Measurement of article weight]
Next, the measurement of the article weight will be described based on the flowchart of FIG.

  The processing of FIG. 4 starts at an interval of 1 msec by, for example, a clock pulse every 1 msec of the clock generation circuit built in the control unit 17 and starts up to the end of FIG. 5, FIG. 6 and FIG. Is prioritized. That is, it is executed with the highest priority every 1 msec.

  The arithmetic circuit of the control unit 17 incorporates a plurality of timer counters described later including an article measurement timer counter TCi.

  As shown in FIG. 8A, the weight of the article is measured from the time t1 when the article G immediately before being carried into the weighing conveyor 7 is detected by the first article detection sensor 12, and the weighing conveyor 7 of the article G is measured. Is carried out within the time (article measurement time Ti) up to the time point t2 immediately before the unloading starts, and at the time point t2 immediately before the carry-in of the subsequent article onto the weighing conveyor 7 is started. Only the article G to be measured is present on the weighing conveyor 7.

  Specifically, the immediately preceding time point t2 is used as the article weight value measurement timing. When the article is detected by the first article detection sensor 12, the article measurement time counting flag F1 is set to “1” at the time point t1. ”To start counting with the article measurement timer counter TCi, and the count value of the article measurement timer counter TCi corresponds to the time t2 immediately before the delivery of the article G from the weighing conveyor 7 is started. When the article measurement time Ti is reached, the weight value is calculated based on the measurement timing of the article weight value.

  As shown in FIG. 4, first, the digital load signal that is the output of the A / D converter 16 is read and subjected to filter processing (steps n1 and n2), and the article measurement time count flag F1 is reset to “0”. It is determined whether or not (step n3).

  When the article measurement time count flag F1 is reset to “0” in step n3, the article has not been detected by the first article detection sensor 12, and therefore the article is detected by the first article detection sensor 12. (Step n4), if not detected, the process proceeds to step n12 in FIG. 5, and when the article is detected, from the time t1 when the article is detected, to the time immediately before the article is unloaded from the weighing conveyor 7. The article measurement timer counter TCi for measuring the article measurement time Ti up to t2 is reset (step n5), and the article measurement time count flag F1 indicating that the article measurement time Ti is being measured is set to “1”. To step n7.

  In step n7, the article measurement timer counter TCi is incremented to measure the elapsed time from the time point t1 when the article is detected, and the count value of the article measurement timer counter TCi is determined by the first article detection sensor 12. It is determined whether or not the article measurement time Ti, which is the time from the detected time t1 to the time t2 at which the article weight is measured, is reached (step n8). If not, the process moves to step n12 in FIG. When it reaches, the article measurement time counting flag F1 is reset to “0” (step n9), and the article weight value reading flag Fi indicating the timing for reading the article weight value is set to “1” (step n10). ), Resets the article measurement timer counter TCi, and proceeds to step n12 in FIG. 5 (step n11). .

  If the article measurement time counting flag F1 is not “0” in step n3, that is, “1”, the article has already been detected and the article measurement time Ti is being measured, and the process proceeds to step n7.

  Thus, when an article is detected by the first article detection sensor 12, the article measurement time count flag F1 is set to “1”, and the article measurement timer counter TCi starts counting. When the count value of the article measurement timer counter TCi reaches the article measurement time Ti (TCi = Ti), the article weight value reading flag Fi is set to “1” on the assumption that the weight value of the article on the weighing conveyor 7 is calculated. And the article measurement timer counter TCi is reset to “0”.

  Next, the article weight value calculation process will be described.

  The calculation of the weight value of the article is executed as a process having a lower priority than those in FIGS. 4 to 7, and specifically, is processed according to the flowchart shown in FIG.

  As shown in FIG. 9, it is determined whether or not the article weight value reading flag Fi is set to “1” (step n101). If not set, the process proceeds to step n107 in FIG. If it is determined that the article weight value reading flag Fi is reset to "0" (step n102), the filter output value Wad of the control unit 17 is read, and the article weight value Wn is calculated and acquired according to the above equation (1) ( The process proceeds to step n103) and step n104.

  As described above, when an article from the product production apparatus 3 is detected by the first article detection sensor 12 immediately before being conveyed on the conveyor line and carried into the weighing conveyor 7, an article measurement timer counter is detected. When the measurement of the article measurement time Ti by the TCi is started and the count value of the article measurement timer counter TCi reaches the article measurement time Ti, the article loaded into the weighing conveyor 7 is a position immediately before being unloaded, The weight value of the article is calculated and acquired on the assumption that the position at the measurement timing at which the subsequent article has not been carried into the weighing conveyor 7, that is, the position at time t2 in FIG.

  In order to generate a no-load state in which no article exists on the weighing conveyor 7, as described above, the article is forcibly removed by the pusher 9 at the front stage of the weighing conveyor 7. As described above, the interval is determined by the number of articles whose weight has been measured, that is, the number of times of measurement of the article weight.

  For this reason, after acquiring the weight value of the article in step n103 of FIG. 9, in step n104, “1” is added to the article weight measurement number counter Cx, and the number of measurements by the counter Cx is the time interval at which the zero point adjustment should be performed. Is determined (step n105). If not, the process proceeds to step n107 in FIG. 10, and if reached, it is necessary to remove the article in order to perform zero adjustment. Assuming that there is a pusher operating condition satisfaction flag Fp indicating that the operating condition of the pusher 9 has been established, it is set to “1”, and the process proceeds to step n107 in FIG. 10 (step n106).

[Measurement of zero weight value]
Next, the measurement of the zero point weight value in an unloaded state in which no article is present on the weighing conveyor 7, that is, the zero point measurement will be described based on the flowchart of FIG. After the zero point measurement is performed, the zero point adjustment is subsequently performed based on the measured zero point weight value.

  First, prior to the description of the flowchart of FIG. 5, an outline of the zero point measurement process will be described.

  As described above with reference to FIG. 4, when the production of articles is performed smoothly and continuously, when the preceding article is weighed and begins to be unloaded from the weighing conveyor 7, the subsequent article is weighed. In order to start being carried in to the conveyor 7, the no-load state in which an article | item does not exist on the measurement conveyor 7 does not generate | occur | produce, and a zero point measurement cannot be performed.

  In this embodiment, since the article is forcibly removed by the pusher 9 before the weighing conveyor 7 as described above, the article is not carried into the weighing conveyor 7, the interval between the articles is increased, and no load is applied. Will occur. The zero point measurement is performed by detecting this no-load state.

  This no-load state is detected as follows. That is, as shown in FIG. 8A, from the time t1 when the article immediately before being carried into the weighing conveyor 7 is detected by the first article detection sensor 12, the article is carried into the weighing conveyor 7 and weighed. After that, the first article detection sensor 12 detects the time (zero point measurement time Tz) from the weighing conveyor 7 to the time t3 when the delivery to the delivery conveyor 8 is completed. When the measurement can be performed, zero point measurement is performed assuming that there is no load on the weighing conveyor 7 at that time.

  Specifically, when the article is detected by the first article detection sensor 12 at time t1 in FIG. 8, the zero measurement time count flag F2 is set to “1”, and the zero measurement time measurement timer counter is set. When the count starts at TCz and the subsequent article is not detected by the first article detection sensor 12, the count value of the zero-measurement time measurement timer counter TCz reaches the zero-point measurement time Tz corresponding to the time point t3. The zero point measurement is performed assuming that no load is present on the weighing conveyor 7 and no article is present.

  When the production of the article is smoothly performed without operating the pusher 9, when the preceding article is weighed and begins to be unloaded from the weighing conveyor 7, the following article becomes the first article. Since it is detected by the detection sensor 12, the zero point measurement time count flag F2 and the zero point measurement time measurement timer counter TCz are reset, and the count value of the zero point measurement time measurement timer counter TCz reaches the zero point measurement time Tz. There is no zero measurement.

  However, when the subsequent article is forcibly removed by the pusher 9 at the front stage of the weighing conveyor 7, the subsequent article is not detected by the first article detection sensor 12, so the count of the zero counter measuring time measuring timer counter TCz is counted. The value reaches the zero point measurement time Tz, and zero point measurement is performed.

  Not only the removal of the article by the pusher 9 but also, for example, when the production of the article by the merchandise production apparatus 3 is interrupted, the no-load state is similarly detected and the zero point measurement is performed.

  Further, in this embodiment, when the operation switch is turned on and the operation of the weight sorter 4 is started, the first article is detected by the first article detection sensor 12 or as described above. When the zero-point measurement is performed without the first article detection sensor 12 detecting the next article, there is no article on the weighing conveyor 7 until the subsequent article is detected by the first article detection sensor 12. Since the load state continues, the zero point measurement is repeated at short time intervals to update the zero point weight value.

  Specifically, after the operation switch of the weight sorter 4 is turned on and the operation is started, when the article is not detected by the first article detection sensor 12, or as described above, the zero counter measuring time measuring timer counter TCz. When the article is not detected by the first article detection sensor 12 after the count value reaches the zero measurement time Tz and the zero measurement is performed, the article is continuously detected by the first article detection sensor 12. Assuming that the article non-detection flag F4 is set to “1” and the update time measurement timer counter TCd measures the update time for updating the zero measurement, the zero measurement update time Td, for example, several tens of milliseconds to 1 A short zero measurement update time Td of about a second is counted, and zero measurement is performed every time the zero measurement update time Td elapses.

  In this embodiment, the first article detection sensor 12 prevents the same article from being detected in consideration of the shape of the article. That is, depending on the shape or the like of the article G, for example, as shown in FIG. 8B, there may be a case where the recessed part 25 is depressed so that the light projection from the first article detection sensor 12 passes. . In such a case, when the concave portion 25 of the article G passes through the detection area of the first article detection sensor 12, the output of the first article detection sensor 12 is detected, non-detected, or detected. In this embodiment, once the article G is detected by the first article detection sensor 12, the article G completely passes through the detection area of the first article detection sensor 12. Until then, the output of the first article detection sensor 12 is ignored.

  Specifically, when an article is detected by the first article detection sensor 12, the duplication detection prevention time counting flag F3 is set to “1”, and counting is started by the duplication detection prevention time measuring timer counter TCm. By this overlap detection prevention time measuring timer counter TCm, the time until the article G finishes passing through the detection region of the first article detection sensor 12 is measured as the overlap detection prevention time Tm, and the overlap detection prevention time measurement timer counter TCm is measured. Until the count value reaches the duplication detection prevention time Tm, the output of the first article detection sensor 12 is ignored.

  When the count value of the duplication detection prevention time measurement timer counter TCm reaches the duplication detection prevention time Tm, it is determined that the article detected by the first article detection sensor 12 has passed the detection area of the sensor 12, and duplication detection is performed. The prevention time count flag F3 is reset to “0”, the overlap detection prevention time measurement timer counter TCm is reset to “0”, and then the zero point measurement time measurement is performed while determining the output of the first article detection sensor 12. The zero point measurement time Tz is counted by the timer counter TCz.

  While the duplication detection prevention time count flag F3 is set to “1”, the duplication detection prevention time measurement timer counter TCm is counted, and the zero point measurement time measurement timer counter TCz is counted. The measurement time measuring timer counter TCz continues counting while the zero point measurement time counting flag F2 is “1”.

  Next, this zero point measurement will be described in more detail based on the flowchart of FIG. The processing for zero point measurement of FIG. 5 is executed subsequent to the weight measurement processing of the article of FIG.

  Here, in order to facilitate understanding, the processing of FIG. 5 will be described by dividing it into processing of a plurality of regions 1 to 6.

  First, in the region 1, in the initial state (F2 = F3 = 0), the zero point measurement time counting flag F2 (step n12) and the duplication detection prevention time counting flag F3 (step n13) are both “0”. Then, it is determined whether or not an article is detected by the first article detection sensor 12 (step n14). In the initial state in which the zero point measurement time count flag F2 and the duplication detection prevention time count flag F3 are both “0”, since the article is not detected by the first article detection sensor 12, the zero point measurement time Tz. In addition, the measurement of the duplication detection prevention time Tm is not performed. In this initial state (F2 = F3 = 0), after the operation switch of the weight sorter 4 is turned on, the first article is detected by the first article detection sensor 12, or after the zero point measurement is performed. This is a state until the subsequent article is detected by the first article detection sensor 12.

  In the initial state, when the article carried into the weighing conveyor 7 is detected by the first article detection sensor 12 (step n14), the processing of the region 2 is executed. Since the article is detected by the first article detection sensor 12, in the region 2, first, the zero point measurement time count flag F2 is set to “1” and the article is detected in order to measure the zero point measurement time Tz. Therefore, assuming that it is no longer necessary to update the zero measurement at short time intervals, the update time measurement timer counter TCd for measuring the zero measurement update time Td is reset to “0” (step n15). Further, since the article has been detected, the duplicate detection prevention time counting flag F3 is set to “1” in order to measure the duplicate detection prevention time Tm (step n16).

  When no article is detected by the first article detection sensor 12 in the initial state of the area 1 (step n14), the process of the area 3 is executed. This area 3 is a process for starting zero measurement every zero measurement update time Td when the article is not continuously detected after the operation switch is turned on or after zero measurement is performed. When the operation switch is turned on, the operation flag Fd set to “1” is reset to “0” when the operation switch is turned on (steps n24 and n25), and no article is detected by the first article detection sensor 12. Assuming that the state continues, the article non-detection flag F4 is set to “1” (step n27). The non-detection flag F4 is reset to “0” when the operation switch is turned off. Next, in order to update the zero point measurement at a short constant time interval, the zero point measurement update time Td is counted by the update time measurement timer counter TCd (step n28). Thereafter, when the state in which the first article detection sensor 12 does not detect the article continues in the initial state (steps n12 to n14), it is determined in this region 3 that the article non-detection flag F4 is “1” (step n26), the update time measuring timer counter TCd is counted (step n28).

  When the count value of the update time measurement timer counter TCd reaches the zero point measurement update time Td (step n29), the update time measurement timer counter TCd is reset (step n30), and the process proceeds to step n23 in the region 2. Then, the zero point weight value reading flag Fz is set to “1”, and zero point measurement is started.

  Thereby, in the initial state, when the state where the article is not detected by the first article detection sensor 12 continues, the zero point measurement is performed at a short time interval of about several tens of milliseconds to 1 second each time the zero point measurement update time Td elapses. Like to do.

  Even when the zero-point measurement update time Td is being measured by the update time measurement timer counter TCd, if an article is detected in the region 1 by the first article detection sensor 12 (step n14), the region 2 as described above is detected. Then, the process proceeds to processing, where the zero point measurement time count flag F2 and the duplicate detection prevention time count flag F3 are set to “1” and the update time measurement timer counter TCd is reset (steps n15 and n16). After that, basically, the processing after step n17 in region 2 or the processing after step n20 is repeatedly executed.

  That is, in the subsequent repeated execution of the highest priority process, it is determined whether or not the zero point measurement time count flag F2 = 1 in the region 1 (step n12), and the first article detection sensor as described above. 12, since the article has already been detected and the zero point measurement time count flag F <b> 2 = 1, the process proceeds to step n <b> 31 in the region 4 to determine whether or not the duplicate detection prevention time count flag F <b> 3 = 1. As described above, since the article has already been detected by the first article detection sensor 12 and the duplicate detection prevention time count flag F3 = 1, the process proceeds to step n17 in the region 2 and is counted by the duplicate detection prevention time measurement timer counter TCm. Then, the overlap detection prevention time Tm as a time sufficient for the detected article to pass through the detection region of the first article detection sensor 12 is measured. .

  The count value of the overlap detection prevention time measurement timer counter TCm is subjected to a determination process (step n18) as to whether or not the overlap prevention detection time Tm has reached the overlap prevention detection time Tm, and further counted by the zero point measurement time measurement timer counter TCz. Then, it is determined whether or not the count value of the measurement time measuring timer counter TCz has reached the zero point measurement time Tz (step n21).

  If the timer counter TCm for measuring the duplicate detection prevention time counts up to the duplicate detection prevention time Tm in step n18, it is determined that the detected article has passed the detection area of the first article detection sensor 12, and the duplicate detection prevention time count is counted. The use flag F3 is reset to “0” and the duplicate detection prevention time measuring timer counter TCm is reset to “0” (step n19). Once the article is detected by the first article detection sensor 12 and the duplicate detection prevention time counting flag F3 is set to “1”, the process proceeds to step n17 in area 2 through step n12 in area 1 and step n31 in area 4. By shifting to, the output of the first article detection sensor 12 can be ignored while the duplication detection prevention time Tm elapses.

  After the duplicate detection prevention time Tm has elapsed and the duplicate detection prevention time counting flag F3 is reset to “0” (step n19), in step n31 of the area 4, the duplicate detection prevention time counting flag F3 is “ Since it is not “1”, the process proceeds to the process of the region 5 and the process according to the output of the first article detection sensor 12 is performed.

  That is, in region 5, on the premise of determination of zero measurement time count flag F2 = 1 in region 1 (step n12) and determination of overlap detection prevention time count flag F3 = 0 in region 4 (step 31). It is determined whether or not the first article detection sensor 12 has detected an article (step n32). If no article is detected, it is determined that the subsequent article has not been detected, and the counter TCz for measuring zero point measurement time is used. In order to continue the measurement of the zero point measurement time Tz, the process proceeds to Step n20 in the region 2.

  When an article is detected in step n32 of area 5, it is determined that the subsequent article has been detected, the process proceeds to area 6, and the zero point measurement time measurement timer counter TCz is reset to “0” (step n33). The measurement time counting flag F2 is reset to “0” and returned to the initial state.

  When the zero point measurement timer counter TCz is timed up (TCz = Tz) in step n21 in the area 2, the article is detected by the first article detection sensor 12, and the subsequent article is detected by the first article detection sensor 12. If the zero point measurement time Tz has passed, that is, it is assumed that the article is not loaded on the weighing conveyor 7, the zero point measurement process is started and the zero point measurement time counting flag F2 is set to “0”. To zero point measurement time measurement timer TCz (step n22), and zero point weight value reading flag Fz is set to "1" (step n23). Since the overlap detection prevention time Tm is shorter than the zero point measurement time Tz, the overlap detection prevention time measurement timer counter TCm has already timed up (TCm = Tm) when the zero point measurement timer counter TCz has timed out. (Step n18), since the duplicate detection prevention time counting flag F3 and the duplicate detection prevention time measurement timer counter TCm have already been reset (Step n19), the initial state of the region 1 (F2 = F3 = TCz = TCm). = 0).

  Next, zero point weight value calculation processing in zero point measurement will be described.

  The calculation of the zero point weight value is executed in a process having a lower priority than those shown in FIGS. Specifically, processing is performed according to the flowchart shown in FIG.

  As shown in FIG. 10, it is determined whether or not the zero-point weight value reading flag Fz is set to “1” (step n107). If it is set, the zero-point weight value reading flag Fz is set to “0”. Since it is reset (step n108) and there is no load on the weighing conveyor 7 and no article is present, the control unit 17 calculates the zero point weight value Wn according to the above equation (1) from the value Wad obtained by reading the output of the filter. (Step n109) Based on the zero point weight value Wn, zero adjustment is performed as Wn + WZ → WZ (step n110), and the process proceeds to step n111. In step n111, whether the zero point adjustment is due to reaching the zero point measurement interval value NCx, or due to the interruption of the article in the middle, and the count value of the article weight measurement number counter Cx and the zero point measurement interval. Judgment is made by comparing the value NCx.

  If the current zero point adjustment is due to reaching the zero point measurement interval value NCx, the zero point weight value measured and stored when the previous zero point adjustment was performed, the zero point weight value measured this time, and the zero point Based on the allowable fluctuation amount and the zero point measurement interval value NCx, which is the time interval from the previous time to the current time, the time interval for operating the pusher 9 next is calculated according to the zero point fluctuation speed in the current time interval. The previous zero point measurement interval value NCx is updated (step n112). Then, the article weight measurement number counter Cx is reset to “0” and the process ends (step n113). The zero point weight value Wn = Z (n + 1) obtained by the new zero point adjustment is stored in the register of the control unit 17 as Z (n) instead of the zero point weight value Z (n) stored so far. .

  If the current zero adjustment is not due to reaching the zero measurement interval value NCx, the process proceeds to step n113, and the article weight measurement number counter Cx for measuring the zero measurement time interval is reset to “0”. finish. In this way, the article is interrupted before the count value of the article weight measurement number counter Cx reaches the zero measurement interval value NCx, and an unloaded state in which no article exists on the weighing conveyor 7 occurs, and zero measurement is performed. When this happens, the article weight measurement number counter Cx is reset to “0” (step n113), so that the zero point measurement interval is measured again, and if this is repeated in a short time, the pusher 9 is activated. I try not to do it.

  Next, determination of the operating condition of the pusher 9 that removes an article in order to perform zero point measurement will be described.

  In the present embodiment, the time interval from the time when zero measurement is performed at a certain timing to the time when the pusher 9 is operated next and the zero measurement is performed is determined by counting the number of times the article weight is measured as described above. .

  In FIG. 9, when the weight of the article is calculated (step n103), the article weight measurement number counter Cx is incremented (step n104). If the weight of the article is continuously measured without performing the zero point measurement, the article weight measurement number counter Cx gradually increases, and when the count value of the counter Cx reaches the zero point measurement interval value NCx (step n105), the pusher 9 is activated. Assuming that the condition is satisfied, the pusher operation condition satisfaction flag Fp is set to “1” (step n106). The zero point measurement interval value NCx is an interval value calculated when the previous zero point measurement was performed, and is updated in step n112 of FIG. 10 as described above.

[Activation of pusher 9]
Next, the operation of the pusher 9 will be described.

  When the number of times the article weight is measured reaches the time interval for the next zero point measurement, that is, when the count value of the article weight measurement number counter Cx reaches the zero point measurement interval value NCx, it is carried into the weighing conveyor 7. 9 is satisfied, that is, the pusher operation condition establishment flag Fp in FIG. 9 is set to “1” (step n106). There are various positions of articles to be removed when established. For this reason, in order for the pusher 9 to accurately remove the article, the article is appropriate when the article is first detected by the second article detection sensor 13 on the side of the feed conveyor 6 after the operating condition is established. The pusher 9 is actuated when it comes to a proper removal position.

  Therefore, when the article is already detected by the second article detection sensor 13 when the operation condition is established, the relationship between the position of the pusher 9 and the position of the article may not be an appropriate removal position. After the article passes and the second article detection sensor 13 once enters a non-detection state in which no article is detected, the pusher 9 is activated when the next article is detected by the second article detection sensor 13.

  If the second article detection sensor 13 has not yet detected the article when the operation condition is established, the pusher 9 is activated when the second article detection sensor 13 detects the next article.

  FIG. 6 shows a process of setting the pusher drive flag Fs at the time when the pusher 9 should be operated, and is a process following the zero point measurement process of FIG.

  In FIG. 6, the pusher drive flag Fs is set at the time when the pusher 9 should be operated while monitoring the output state of the second article detection sensor 13 using the first to third detection flags Fa to Fc. is there.

  The first detection flag Fa waits for a time when the article is not detected by the second article detection sensor 13 and the article is detected by the second article detection sensor 13 when the above operating condition is satisfied. It is a flag indicating that it is in a state.

  The second detection flag Fb is a flag indicating that the article has already been detected by the second article detection sensor 13 at the time when the operation condition is established.

  In the third detection flag Fc, when the operating condition is established, the article has already been detected by the second article detection sensor 13, the detected article passes through the second article detection sensor 13, and the next article is It is a flag indicating that it is in a state of waiting for a timing detected by the second article detection sensor 13.

  As shown in FIG. 6, first, it is determined whether or not the first detection flag Fa is set to “1” (step n35). When the first detection flag Fa is not set to “1”, the second detection flag Fb is set to “1”. It is determined whether or not “1” is set (step n36). If it is not set to “1”, it is determined whether or not the third detection flag Fc is set to “1” (step n37). , When it is not set to “1”, it is determined whether or not the pusher operation condition establishment flag Fp is set to “1” (step n38). When it is not set to “1”, the step of FIG. The process proceeds to n51, and when it is set to “1”, the pusher operation condition establishment flag Fp is reset to “0” and the process proceeds to Step n40, assuming that the pusher operation condition is established.

  In step n40, it is determined whether or not an article is detected by the second article detection sensor 13. If not detected, the article is still detected by the second article detection sensor 13 when the operating condition of the pusher is established. If not, the first detection flag Fa is set to “1” and the process proceeds to step n51 in FIG. 7 (step n41).

  Further, when the article is detected by the second article detection sensor 13, the second detection flag Fb is set to “2” assuming that the article has already been detected by the second article detection sensor 13 when the pusher operating condition is satisfied. 1 "and the process proceeds to step n51 in FIG. 7 (step n42).

  In step n35, when the first detection flag Fa is set to “1”, that is, when the second article detection sensor 13 has not yet detected the article when the pusher operating condition is satisfied, 2 It is determined whether or not an article is detected by the article detection sensor 13 (step n48). If not detected, the process proceeds to step n51 in FIG. 7, and if detected, the article is detected after the operating condition of the pusher is established. First, the first detection flag Fa is reset to “0” (step n49), and the pusher drive flag Fs is set to “1”, assuming that it is the timing when the pusher 9 is actuated for the first time. Then, the process proceeds to step n51 in FIG. 7 (step n50).

  In step n36, when the second detection flag Fb is set to “1”, that is, when an article has already been detected by the second article detection sensor 13 when the pusher operating condition is satisfied, 2 It is determined whether or not an article is detected by the article detection sensor 13 (step n43). When the article is detected, the article detected by the second article detection sensor 13 is passing the detection area of the sensor 13. If there is, the process proceeds to step n51 in FIG. 7 and if it is not detected, it is determined that the article detected by the second article detection sensor 13 has passed the detection area of the second article detection sensor 13, and the third detection flag Fc is set to “ 1 ”(step n44), the second detection flag Fb is reset to“ 0 ”, and the process proceeds to step n51 in FIG. 7 (step n45).

  In step n37, when the third detection flag Fc is set to “1”, that is, when the pusher operating condition is satisfied, the article detected by the second article detection sensor 13 is detected as the second article detection. When the detection area of the sensor 13 is passed, it is determined whether or not the next article is detected by the second article detection sensor 13 (step n46). If not detected, the process proceeds to step n51 in FIG. When it is time to activate the pusher 9, the third detection flag Fc is reset to “0” (step n47), the pusher drive flag Fs is set to “1”, and the process proceeds to step n51 in FIG. Step n50).

  Next, the driving of the pusher 9 will be described based on the flowchart of FIG. FIG. 7 is a process following the process of FIG.

  First, it is determined whether or not a pusher driving flag Fv indicating that the pusher 9 is being driven is set to “1” (step n51), and when it is set, the pusher 9 is being driven. The process proceeds to step n57, and when it is not set, it is determined whether or not the pusher drive flag Fs is set to "1" (step 52). When it is not set, the process ends. When it is set, It is determined whether or not an article is detected by the second article detection sensor 13 (step n53). If it is not detected, the process ends. If it is detected, the process proceeds to step n54.

  In step n54, the pusher driving flag Fs is reset to “0”, the pusher driving flag Fv is set to “1” (step n55), the output of the pusher driving signal is turned on, and the pusher 9 is driven (step n54). n56), the driving time measuring timer counter Cp for measuring the driving time of the pusher 9 is incremented (step n57), and it is determined whether or not the count value of the driving time measuring timer counter Cp has reached the driving time Tp. (Step n58) When not reached, the process ends. When reached, the pusher driving flag Fv is reset to “0” (Step n59), and the pusher driving signal output is turned off to stop the driving of the pusher 9. And end (step n60).

  As described above, according to the present embodiment, the pusher 9 is operated to remove the article out of the conveyance line, so that there is no article on the weighing conveyor 7 without changing the article conveyance speed by the conveyance line. Since it can be in a no-load state, zero adjustment can be performed without stopping the transfer line or reducing the transfer speed. Thus, since the zero point adjustment is not required, it is not necessary to stop the conveyance line or decrease the conveyance speed, so that the zero point adjustment can be easily performed without causing the article to stay.

  In addition, the time interval for performing zero adjustment by causing a no-load condition is shortened when the zero fluctuation speed is large, and is increased when the zero fluctuation speed is small. Thus, the zero point fluctuation amount does not increase and the measurement accuracy of the weight value of the article does not decrease, or conversely, the time interval for performing the zero point adjustment is too short, and the weighing processing capacity does not decrease.

<Embodiment 2>
In the above embodiment, the operation interval of the pusher 9, that is, the interval at which the zero point adjustment is performed with the weighing conveyor 7 in the no-load state is varied according to the zero point fluctuation speed of the weight sorter 4, but is measured by the weighing conveyor 7. You may make it vary based on the weight value of the article to be.

  In this embodiment, the time interval for performing the zero adjustment is varied based on the amount of change in the weight value of the article to be measured. There are cases where the weight value of the article fluctuates on the product production apparatus 3 side and on the weight sorter 4 side, but at least the zero point of the weight sorter 4 may fluctuate greatly. Therefore, zero adjustment is performed.

  Since the weight measurement value of each individual article includes a large amount of variation due to factors on the product production device 3 side or the weight sorter 4 side, it represents a variation in the weight measurement value as a whole despite variation. Information is calculated, and a time interval for performing the zero adjustment is determined based on the magnitude of the information representing the tendency variation of the weight measurement value of the article.

  In this case, the calculation of the time interval for performing zero adjustment differs depending on whether the article transport system is the next first system or the second system.

  In the first system, the article conveying system calculates the average value of the weight values of the articles measured by the weight sorter 4 or the deviation (average deviation) of the average value of the weight values from the target weight value of the articles. The product production device 3 feeds back to the device 3 and automatically changes according to the deviation (average deviation) calculated from the average value of the fed back weight values or the feedback (average deviation). The second system is a system having no feedback, and the second system is a system having no feedback.

  In the first system of feedback for correcting the deviation, if the value is an average deviation, the amount of variation included in the weight measurement value of the individual article is reduced, and the overall trend is represented. Hereinafter, description will be made by applying to each system.

(1) First System First, description will be made by applying to the first system.

  In the first system, when the average value of the weight values of the articles measured by the weight sorter 4 varies, the weight value of the articles produced by the commodity production apparatus 3 upstream in the conveyance direction of the articles varies. Every time the average weight value is obtained, the average weight value or the deviation (average deviation) is fed back to the product production apparatus 3, and the product production apparatus 3 automatically adjusts the production weight of the article so as to eliminate the average deviation. When the average weight value of the article is fed back to the product production apparatus 3, a deviation (average deviation) is calculated on the product production apparatus 3 side.

  However, even when the zero point of the weight sorter 4 fluctuates, the average value of the weight measurement value of the article fluctuates from the target weight value, so that the commodity production apparatus 3 sequentially increases the amount of the zero point fluctuation by the operation of the feedback function. Increase or decrease the weight.

  In addition, the control is sequentially performed even if the deviation is small so that the average value does not greatly deviate from the target weight value.

  Accordingly, even if it appears that the weight measurement of the article is producing the article according to the target weight value, the actual weight of the article is different from the target weight value.

  For this reason, if the fluctuation amount of the average value of the weight measurement value of the article is used, it is difficult to detect the zero point fluctuation of the weight sorter 4.

  Therefore, in the case of the first system, the time point at which the zero point adjustment is performed by the magnitude of the integrated value (cumulative value) of the deviation (average deviation) output by the weight sorter 4 after the zero point adjustment is performed, that is, The time point at which the pusher 9 is activated is determined. The cumulative value of the average deviation also represents the variation in the weight measurement value, that is, the tendency of the degree of separation of how far away from the target weight value of the weight measurement value.

  Specifically, when the zero adjustment is performed, the integrated value (cumulative value) of the deviation (average deviation) is reset, and the positive and negative deviations (average deviation) values obtained after the zero point adjustment are integrated. Then, the absolute value of the integrated value (cumulative value) Wet is compared with a predetermined allowable value Wf, and if the absolute value of the integrated value Wet exceeds the allowable value Wf, the pusher 9 is actuated as the time of zero adjustment. It is something to be made.

  The integrated value (cumulative value) of the deviation (average deviation) varies depending on the weight variation of the article due to the factor on the commodity production apparatus 3 side. Therefore, an abnormal increase in the integrated value of the deviation (average deviation) is also caused by an abnormality on the product production apparatus 3 side, but at least there is a probability that the zero point in the weight sorter 4 is largely fluctuated. Therefore, if the absolute value of the integrated value (cumulative value) Wet of the deviation (average deviation) exceeds the allowable value Wf, zero adjustment is performed.

  If a failure that abnormally increases the weight value of the article on the product production device 3 side and a failure that abnormally decreases the zero weight value on the weight sorter 4 side occur simultaneously, or the opposite phenomenon occurs simultaneously. If it occurs, the fluctuation of the integrated value of the deviation (average deviation) remains small, but the probability of the simultaneous occurrence of such a failure is extremely small.

  Next, how to determine an allowable value to be compared with the integrated value of the deviation (average deviation) will be described.

  As a method of determining the allowable value, it is preferable to determine based on the variation amount of the weight of the article produced by the normal product production apparatus 3 and the measurement variation amount in the weight measurement in the weight sorter 4.

  For example, if the commodity production apparatus 3 is a volume filling machine as in this embodiment, the tolerance is determined even when a constant filling amount is set every time, and the weight of the article is determined. Variations occur in the filling weight.

  It is assumed that the variation amount in the production of the article weight is represented by the standard deviation value ws1. The standard deviation value ws1 is obtained in advance by producing the same sample product as the product on the product production device 3 side in the adjustment stage under the same conditions as in operation.

Further, the weight sorter 4 has measurement variations due to weighing conditions and article properties.
It is assumed that the variation amount in the measurement of the article weight is represented by the standard deviation value ws2. The standard deviation value ws2 is obtained in advance by weighing the sample product in the weight sorter 4 under the same conditions as in operation during the adjustment stage.

Since both of the variation amounts are independent from each other, the standard deviation WS of the total variation amount of the amount of the articles measured by the weight sorter 4 is
^{WS = (ws1 2 + ws2 2} ) 1/2
Is required.

Since this is an allowable value for the average deviation,
Since the k sigma value of the standard deviation of the M average weight values is k · [WS / (M) ^1/2 ], for example, when k = 2, 2 · [WS / (M) ^1/2 ] is set. Assuming that the tolerance value for the normal fluctuation amount is the tolerance value, the absolute value of the deviation of the average value of the latest M article weight measurement values that are generated every time one article is weighed with respect to the target weight value is the tolerance value. 2. If the probability of exceeding [WS / (M) ^1/2 ] becomes high, the pusher 9 is operated to adjust the zero point.

  In order to obtain the latest measured value of the weight of the M articles, a shift register in which M cell memories for storing the measured value of the weight of one article are connected in series is provided, and the latest weight of the M articles is always provided. The measured value is memorized.

(2) Second System Next, description will be made by applying to the second system.

  In the second system, since feedback correction is not applied, the above deviation (average deviation) varies depending on factors on the product production device 3 side and factors on the weight sorter 4 side unless the operator performs any repair operation. .

  Accordingly, the absolute value of the deviation (average deviation) after the zero point adjustment is compared with a predetermined allowable value, and if it exceeds the allowable value, there is a possibility that abnormal fluctuation has occurred on the product production apparatus 3 side. However, the pusher 9 is actuated in order to perform zero-point adjustment on the assumption that there is a high probability that a large zero-point fluctuation has occurred after the zero-point adjustment.

  The allowable value in this case may be the same value as the allowable value Wf in the case of the first system.

  In this second system, as a method for determining the time interval for performing the zero adjustment, the absolute value of the deviation (average deviation) after the zero adjustment is compared with a predetermined allowable value as follows. It may be determined in this way.

  That is, the tendency of the fluctuation amount of the weight measurement value of an individual article is determined. Specifically, for example, in addition to the boundary value for weight selection such as the excessive amount, appropriate amount, and light weight of the article, the variation amount in the product production apparatus 3 and the variation amount of the weight measurement value in the weight sorter 4 alone are included. Then, considering the total variation amount in the article weight measurement value of the weight sorter 4 as described later, either or both of the fluctuation amount of the article weight value of the product production apparatus 3 and the zero point fluctuation amount of the weight sorter 4 An upper limit weight value and a lower limit weight value representing a boundary value (or an allowable value determined to be normal) for determining the fluctuation amount in the increase / decrease direction as abnormal are set.

  Again, the measurement is performed on the weight measurement value of the article after the zero point adjustment.

  When the weight of the article fluctuates due to the deviation of the zero point of the weight sorter 4 or the deviation of the production weight due to the malfunction of the commodity production apparatus 3, the predetermined number of articles having a weight exceeding the upper limit weight value are continuous, Even if it is intermittent, in the measurement period of the number Nm of the latest predetermined article weight set in advance, it appears with a probability higher than the preset probability Ra, or articles with a weight less than the lower limit weight value continue, Even if it is true, it is determined whether or not it appears with a probability Ra higher than the preset probability in the measurement period of the number Nm of the latest predetermined article weight set in advance.

  However, since the deviation in the positive or negative direction is evaluated regardless of the fluctuation amount of the production weight value or the fluctuation amount of the zero point weight value, the aggregation / judgment regarding the articles whose weight exceeds the upper limit weight value, and the lower limit weight Aggregation / determination for articles with a weight less than the value is determined separately by calculating separately.

  When the Na pieces are continuous or appear with a probability higher than the probability Ra, the production weight value or the zero point weight value tends to have a large fluctuation in the positive direction or the negative direction on a regular basis. Therefore, the pusher 9 is operated to adjust the zero point.

The upper limit weight value, lower limit weight value, and target weight value are
The upper limit weight value> target weight value (or reference weight value)> lower limit weight value is set, but instead of setting these directly, the production target weight value is set, and the upper limit weight value is the target weight value. The upper limit deviation weight value and the lower limit weight value with respect to (or the reference weight value) may be set by setting the lower limit deviation weight value with respect to the target weight value (or the reference weight value).

  For the latest Nm weight measurement values, the identification result indicates whether the weight measurement value exceeds the upper limit weight value, is less than the lower limit weight value, is less than the upper limit weight value, and is greater than or equal to the lower limit weight value. A shift register to be stored is provided, and each time one determination result is obtained, the continuous number Na or the probability Ra may be evaluated for the determination result stored in the register.

  For example, each determination result is A, B, C, that is, A when the weight measurement value exceeds the upper limit weight value, B when the weight measurement value is equal to or less than the upper limit weight value and equal to or greater than the lower limit weight value, and the weight measurement value Is C when the weight is less than the lower limit weight value, and the pusher 9 is operated to adjust the zero point with the latest six determination results.

  If the number of consecutive Na is an allowable number of consecutive = 3 and there is a possibility of large zero fluctuation, the zero adjustment will be performed if three shift registers A, A, A, or C, C, C are consecutive. To do so, pusher 9 is activated.

  Regarding the determination by probability, if the allowable value is 4/6 = 2/3, the contents of the shift register are A, B, A, B, A, A, C, B, C, C, B, C. Thus, when A or C is present in four or more of the six, the pusher 9 is actuated to perform zero adjustment.

  In short, we would like to perform zero adjustment even if the zero fluctuation amount is small, but there are variations in the weight measurement values of individual articles, and if a small allowable value is set, the zero value is often adjusted by mistake. , Or by handling statistical / probabilistic information, it is possible to determine the magnitude of the trending zero variation.

  Further, in order to detect a trendy change, the upper and lower limit weight values are set for the latest P average values of the article weights, and the same judgment criteria as those for the individual article weight values are set. , And the pusher 9 may be operated to adjust the zero point.

  Next, an embodiment applied to the first system will be further described.

  In this embodiment, the magnitude of the feedback correction amount accumulated after the time when the zero adjustment is performed is determined, and the time when the zero adjustment is performed is determined.

  Specifically, an article produced by feeding back the deviation (average deviation) wea between the average weight measurement value (net weight value) of the latest M articles and the target weight value Wo of the article to the commodity production apparatus 3. The weight value is corrected.

  The processes in FIGS. 4, 5, 6, and 7 are the same as those in the above embodiment.

  FIG. 11 is a flowchart corresponding to FIG. 9 of this embodiment.

  As shown in FIG. 11, it is determined whether or not the article weight value reading flag Fi is set to “1” (step n101). If not set, the process proceeds to step n112 in FIG. 12 and is set. Sometimes, the article weight value reading flag Fi is reset to “0” (step n102), the filter output value Wad of the control unit 17 is read, and the article weight value Wn is calculated according to the above equation (1). The weight value Wx of the net article is calculated by subtracting the weight of the container and the packaging material (step n103), and the obtained weight value Wx of the article is stored in a shift register having M cells (step n104). The process proceeds to step n105.

  In step n105, it is determined whether or not the weight value Wx of M articles is stored in the shift register. If not stored, the process proceeds to step n112 of FIG. 12, and if stored, M articles are stored. An average value Wxa of the weight value Wx of the article is calculated (step n106), an average deviation Wea (= Wxa−Wo) that is a deviation from the net target weight value Wo of the article is calculated (step n107), and the process proceeds to step n108. .

  In step n108, the average deviation Wea is fed back to the product production device 3 together with its polarity, and the average deviation Wea is integrated to calculate the cumulative average deviation Wet (step n109), and the process proceeds to step n110. In the product production device 3, the filling amount is corrected so as to eliminate the fed back average deviation Wea.

  In step n110, it is determined whether or not the absolute value | Wet | of the cumulative average deviation is larger than the allowable value Wf. If not, the process proceeds to step n112 in FIG. 12, and the absolute value | Wet | When the value is larger than the allowable value Wf, it is assumed that the article needs to be removed in order to perform the zero adjustment, and the pusher operation condition establishment flag Fp indicating that the operation condition of the pusher 9 is established is set to “1”. Then, the process proceeds to Step n112 of Step 12 (Step n111).

  FIG. 12 is a flowchart corresponding to FIG. 10 of the above embodiment.

  In step n112 of FIG. 12, it is determined whether or not the zero-point weight value reading flag Fz is set to “1”. If it is not set, the process ends. If it is set, the zero-point weight value reading flag Fz is set. Since it is reset to “0” (step n113) and there is no load on the weighing conveyor 7, there is no load, so the control unit 17 uses the value Wad obtained by reading the output of the filter according to the above equation (1). Wn is calculated (step n114), zero point adjustment is performed as Wn + WZ → WZ based on the zero point weight value Wn (step n115), and the process proceeds to step n116. In step n116, the cumulative average deviation Wet is reset to “0” and the process ends.

[Other Embodiments]
(1) In the above embodiment, the operation interval of the pusher 9, that is, the interval at which the zero point adjustment is performed with the weighing conveyor 7 in an unloaded state, is varied based on the zero point fluctuation speed of the weight sorter 4 and the weight value of the article. However, as another embodiment of the present invention, the time may be varied according to the elapsed time from the time point set in advance by operating the input unit 8, such as the operation start time of the weight sorter 4.

  That is, the interval at which the zero adjustment is performed may be controlled in accordance with the characteristics of the zero fluctuation amount depending on the installation environment of the weight sorter 4.

  The zero point fluctuation speed of the weight sorter 4 fluctuates quickly and greatly immediately after the power is turned on due to the warm-up characteristics of the load sensor and the measurement circuit, changes in the ambient temperature, and the like, and the fluctuation amount gradually becomes smaller.

  Therefore, for example, the start time of the weight sorter 4, that is, the time when the weight sorter 4 is powered on is set, the elapsed time from this point is counted, and the operating interval of the pusher 9 is changed to zero. You may make it control the space | interval which performs adjustment.

  For example, if the zero point fluctuation amount reaches the zero point fluctuation allowable amount in 20 minutes until 1 hour has passed since the power-on time, the operation interval of the pusher 9 is set to 20 minutes, and one hour has passed since the power-on time. If the zero-point fluctuation amount reaches the zero-point fluctuation allowable amount in 40 minutes until 2 hours elapses, the operation interval of the pusher 9 is set to 40 minutes. However, if the zero point variation allowable amount is reached in 60 minutes, the operation interval of the pusher 9 is set to 60 minutes.

  In this way, the starting time of the start of work is set in advance, and the zero interval is adjusted at a time interval according to the installation environment of the weight sorter 4 by setting the operation interval according to the elapsed time from that time. It becomes possible.

  Further, this embodiment may be combined with the second embodiment.

  (2) In the above embodiment, the article removal apparatus such as the pusher 9 removes the article from the conveying line before being carried into the weighing conveyor 7, but the product production apparatus is a filling apparatus, a combination scale, or the like. For example, it may be configured as shown in FIG.

  FIG. 13 is a schematic configuration diagram corresponding to FIG. 1A, and corresponding portions are denoted by the same reference numerals.

  Production devices such as the filling device 1 and the combination weigher constituting the product production device 3 produce articles at almost predetermined time intervals in normal operation. Therefore, instead of the pusher operation signal of the above embodiment, the pusher operation condition establishment flag Fp in FIG. 9 is set to “1” for the production apparatus that produces articles at these predetermined time intervals. , A pause signal for temporarily stopping one or a plurality of articles continuously is transmitted.

  The production apparatus that has received the pause signal temporarily pauses the production of the article and continuously pauses the production of one or a plurality of articles during the period of receiving the pause signal.

  As a result, one or a plurality of vacant spaces are generated in the flow of articles in the downstream conveyance line, so that the conveyance interval of articles carried into the weighing conveyor 7 increases continuously, and the weighing conveyor 7 is in an unloaded state. As a result, the zero point can be adjusted. In this case, a delay is caused by the amount of articles existing between the product production device 3 and the weight sorter 4, but the zero sorter can be adjusted by the weight sorter 4.

  According to this embodiment, there is an advantage that the processing operation of the removed article does not occur, and it is not necessary to install a removal device such as the pusher 9 or the second article detection sensor 13.

  (3) In the above embodiment, the article removal device such as the pusher 9 removes the article from the conveying line before being carried into the weighing conveyor 7. However, as another embodiment of the present invention, the preceding stage of the weighing conveyor 7 is used. 9 is provided with a notification means such as a display lamp for notifying the operator that the article should be removed and zero adjustment should be performed. For example, the pusher operation condition establishment flag Fp in FIG. Instead of the pusher operation signal of the above-described embodiment, a display lamp or the like may be turned on at the set timing, and the operator may remove the article manually by this lighting. In this case, it is not necessary to install a removal device such as the pusher 9 or the second article detection sensor 13.

DESCRIPTION OF SYMBOLS 1 Filling apparatus 2 Packaging apparatus 3 Commodity production apparatus 4 Weight sorter 5 Conveying conveyor 6 Feeding conveyor 7 Weighing conveyor 8 Sending conveyor 9 Pusher 10 Load sensor 11 Controller 12 First article detection sensor 13 Second article detection sensor G Article

Claims (8)

A weighing device provided in a conveyance line for conveying an article and weighing the article while conveying the article, and a conveyance interval for increasing the article conveyance interval without changing the article conveyance speed by the conveyance line Change means,
The weighing device has a control unit that controls the conveyance interval changing unit, a no-load state detection unit that detects a no-load state in which no article exists on the weighing conveyor, and when the no-load state is detected, A zero point adjustment unit that measures the zero point weight value of the weighing conveyor and adjusts the zero point,
The control unit of the weighing device controls the conveyance interval changing unit so that the no-load state occurs.
An article conveying system characterized by the above. The control unit of the weighing device varies the time interval for causing the no-load state by controlling the conveyance interval changing unit.
The article conveyance system according to claim 1. The control unit of the weighing device varies the time interval for causing the no-load state according to an elapsed time from a preset time point.
The article conveyance system according to claim 2. The control unit of the weighing device varies the time interval causing the no-load state according to a zero point fluctuation speed of the weighing device,
The article conveyance system according to claim 2. The control unit of the weighing device varies the time interval causing the unloaded state based on a weight value of the article to be weighed by the weighing conveyor.
The article conveyance system according to claim 2 or 3. The conveyance interval changing means is an article removal device that increases the conveyance interval of articles by removing the articles from the conveyance line.
The article conveyance system according to any one of claims 1 to 5. The transport interval changing means is a production device that continuously produces the article and sends it to the transport line, temporarily stopping the production of the article and increasing the transport interval of the article.
The article conveyance system according to any one of claims 1 to 5. A weighing device provided in a conveyance line for conveying an article and having a weighing conveyor for weighing while conveying the article,
A control unit that controls a conveyance interval changing unit that increases the conveyance interval of the article without changing the conveyance speed of the article by the conveyance line, and no load that detects a no-load state in which no article exists on the weighing conveyor A state detection unit, and a zero point adjustment unit that measures the zero point weight value of the weighing conveyor and performs zero point adjustment when the no-load state is detected,
The control unit of the weighing device controls the conveyance interval changing unit so that the no-load state occurs.
Weighing device characterized by that

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