CN1235649A - Inlet measuring device for drafting unit - Google Patents

Abstract

This invention concerns a process and a device for detecting a parameter on several bands fed into a controlled drawing equipment. To produce a more precise measured value with minimum interference to the bands, several measuring elements (9) are associated individually with the bands, the measured values of which can be converted into a single measured value for purposes of regulation.

Description

Inlet measuring device for drafting unit

The invention relates to a method and a device for determining parameters on a plurality of slivers fed to a drafting device.

US Pat. No. 4,974,296, for example, discloses a drafting device to combine and draw a plurality of textile fiber strands drawn from a plurality of cans into a uniform strand. Such a drafting device has a measuring device at the inlet, which is used to determine cross-sectional fluctuations or mass fluctuations on a plurality of strips. Such measuring devices are distributed over all the bars to be fed, measure all bars together and output a measured value together for all bars.

This known device makes it possible to test a plurality of strips inductively or mechanically, for example by pressing rollers. If rollers are used, the pressure on the strip is generally high to obtain accurate measurements. Among them, the properties of the fiber strips vary greatly and are interconnected to bring adverse effects on the subsequent drawing process. When measuring parameters with inductance, the measurement is influenced, for example, by humidity. The humidity can affect the entire sliver collectively from the outside, or it can also only affect individual slivers, for example, before drawing, because individual slivers are affected by the humidity in their cans more than other fiber slivers. The known methods and devices therefore work with imprecise test values or already unfavorable pretreated fiber slivers.

Therefore, the present invention, as stated in the characterizing parts of the claims, proposes a method and a device of the above-mentioned kind which lead to more accurate measurements with as little influence as possible by the fiber strands.

This object is achieved in that the parameter is measured individually on each fiber sliver and then converted to a common measured value for a plurality of fiber slivers. For this purpose, the inlet measuring device is equipped with measuring cells individually assigned to the fiber sliver, which are all connected to a computer. The computer provides a measurement signal for the drafting control process, which consists of individual test values which are output by the measuring device. These measuring elements are arranged at the can outlet and are preferably part of the device for pulling the fiber sliver out of the can. Therein, if the cans are arranged in a row, there are distances of different lengths between the measuring device and the inlet of the drafting device.

The advantage achieved by the invention is in particular that the individual fiber slivers do not influence each other during the measurement, so that all parameters measured on the fiber sliver to be fed are comparatively accurate. The individual measuring elements can be designed relatively easily in such a way that they respond quickly to changes in the parameters and can output these changes quickly and precisely as measured values. In addition, there are measuring cells available for mechanical testing of the fiber sliver, for which the fiber sliver has to be driven in the range of the measuring cell. But can realize this drive fully with the drive device at the can outlet. The more precise values thus obtained can be used in the drafting control for a more precise and better control according to parameter fluctuations. This ultimately leads to a uniform fiber sliver at the output of the drafting device which corresponds exactly to the theoretical values of the parameters. Furthermore, there is the possibility that the measuring elements perform other functions, for example they can monitor individual slivers and issue an indication, an alarm or other functions in the case of particularly bad slivers.

The present invention will be described in detail below in conjunction with an embodiment and with reference to the accompanying drawings. The accompanying drawings indicate:

Fig. 1 and Fig. 4 represent the structural representation of a controllable drafting device with an entrance measuring device respectively;

Figure 2 shows the measuring elements of the inlet measuring device;

Fig. 3 and Fig. 5 represent the structural representation of the computer of the signal processing of single measuring element respectively;

Figure 6 shows a schematic diagram of the processing of measured values for controlling the drafting device.

FIG. 1 shows a drafting device 1, which consists of a plurality of roller pairs 2, 3, 4 in a known manner, of which only one roller in each case can be seen. Downstream of the drafting device 1 are arranged a sliver bell 5, a calender roller 6 and a can 7 which holds the controllable fiber sliver. These are all well known elements. 8 cans 10a to 10h with guide wheels 8 and 8 measuring elements 9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h and 8 fiber strips 11a to 11h, seen upstream from the drafting device 1 . All measuring elements 9 are connected in parallel to a computer 13 by wires 12a to 12h. The computer is also connected to an operating unit 14 and a tachometer 15 , which is arranged, for example, on the drive line 16 of the measuring element 9 . Measuring element 9 can here be part of a device that draws fiber sliver 11 from a can 10 . The drafting device 1 is equipped with a servo motor 17 and a main motor 18, which are connected on the one hand to a servo drive 19 and on the other hand to the roller pairs 2, 3, 4 and the calender roller 6 .

FIG. 2 shows the measuring element 9 of the fiber sliver 11 , which for example consists of a drive roller 20 and a driven roller 21 which is mounted on a rod 23 and is rotatable about a rotational axis 22 . The drive roller 20 provides, for example, a groove for the fiber sliver 11 into which the roller 21 can also enter in order to measure the fiber sliver 11 .

FIG. 3 shows a possible configuration of the computer 13 . In this configuration, a delay element 25 with sections 25a to 25h and an adder 26 are provided for individually delaying the signal of each associated measuring element 9a to 9h. The adder is followed by a linearization stage 27 , a delay stage 28 , a digital/analog converter 29 and a connection 30 to the actuating drive 19 . A multiplier 36 with a signal input of the measuring element 9 , a digital/analog converter 37 and a signal splitter 38 are connected upstream of the delay element 25 . Delay element 25 and delay stage 28 are additionally connected via a speed computer 31 to a counter 32 which can also be part of tachometer 15 and counts pulses. The linearization stage 27 has an input 33 for at least one linearization parameter. The delay element 25 has a speed output 84 and distance inputs 40a to 40h, by means of which the magnitude of the delay in the individual segments 25 to 25h can be determined. The delay stage 28 likewise has an input 41 for the sliver velocity and an input 42 for the distance or travel of the sliver 11 .

FIG. 4 shows a drafting device 1 with an inlet measuring device, the principle of which is already shown in FIG. 1 . Therefore, the same reference symbols are used for the same parts, and this regulation is also applicable to the situation where there are no symbols marked in the figure. However, FIG. 4 differs in that measuring elements 9 a to 9 h are connected in series with computer 13 via a data bus 35 .

FIG. 5 shows a structure of the computer 13 similar to that of FIG. 3, so the same reference symbols are used for the same parts here. In front of the delay element 25 there is of course a serial interface 24 , to which the data bus 35 is connected with the measuring element 9 .

Figure 6 shows a partial schematic view of some aspects of the way the drafting device 1 and the control system work. The drafting device 45 and the controller 46 here therefore have an important function of signal processing. 47a to 47h here designate defect variables or fiber strand defects which can be determined at test points 48a, 48b, 48h. Of course, for the sake of clarity, only the defect variables 47a, 47b, 47h are shown in the figure. In fact, the number of corresponding defect variables and thus connected elements and fiber strips is the same. The defect variables 47a to 47h generate measurement signals for the controller 46 at test points 48a to 48h. After the test point 48 , the defect variables are moved in a different and individual sliver-specific time course until they reach the actual drafting device or a reference point 39 . This means that defective variables are delayed in function blocks 50a, 50b and 50h. Counting from reference point 39 , all slivers and all defect variables 47 have the same delay performed in function block 52 . This reference point can be located before or in the drafting device and is represented here by a summer 51 . In the controller 46 are provided corresponding function blocks 53a, 53b, 53h as well as function blocks 54 and 55 for the individual delay of the measurement signals, for the common delay of the measurement signals and for the addition of the measurement signals. Designated at 56 is a control point in the drafting unit which receives a delayed control variable from the controller 46 and thus changes the drafting in the drafting unit. This produces a controlled variable 58 or a corrected uniform fiber sliver at the output of the drafting device.

It works like this:

Each strip 11 to be fed to the drafting device 1 is first parameterized in a measuring cell 9 . As parameters, there are mainly weight, thickness, mass, etc. as absolute values, or changes in weight, thickness, or mass as relative values. These parameters are determined in a measuring cell 9 as shown in FIG. 2 . In this case, for example, the volume exerted by the strip 11 on the roller 20 deflects the roller 21, which is converted into an output signal proportional to this deflection. The output signals of all measuring elements 9 are fed in series via the data bus 35 or in parallel via the line 12 into the computer 13, which calculates all the output signals into an output signal representing the corresponding parameter value, which is fed into the servo drive 19. In this way, the drafting device 1 is adjusted in a well-known manner, so that no further description is given here.

When the output signals are input to the serial interface 24 of the computer 13 via the bus 35, these output signals are individually delayed in the delay element 25 in such a way that the individual measuring elements 9 or the guide pulleys 8 follow the fiber sliver 11 to the first roller pair 2 or to the tractor The different distances A ( FIG. 4 ) of another selectable reference point 39 in or in front of the extension device 1 are compensated according to the position of these measuring elements 9 at the correspondingly selected reference point 39, so that the value of the delay is then in the adder 26 are added to a value and this value is linearized in a linearization stage 27 . A common delay of all signals is optionally carried out in the delay stage 28 , which is only necessary if the above-mentioned reference point 39 is provided and is located at a certain distance B before the control point 56 of the drafting device 1 . However, the distances A and B can also be compensated together in one delay element 25 . In the digital/analog converter 29 the parameter values of all fiber slivers 11 are now summed up and converted into an analog signal which is output to the servo drive 19 via the output 30 .

If these output signals are input via line 12, they are multiplied in a multiplier 36 before they are signal separated in a demultiplexer 38 and individually delayed in a known manner in a delay element 25, and in the digitized in converter 37.

As shown in FIG. 6, the measurement signal undergoes the same delay and logical combination as the individual sliver or sliver-related interfering signals. In order to achieve such a delay, these parameters can be entered into the controller 13 via the inputs 40 and 42 .

Of course, other measuring elements than those shown in FIG. 2 can also be used for each parameter. But this is only necessary if other parameters such as fiber fineness or color are used to control the drafting device 1 . These other measuring elements or measuring principles are described, for example, in Swiss Patent Application No. CH 2128/95.

The method and the device according to the invention can also be used in combined open and closed control systems or in combination with a monitoring device for a fiber sliver to be delivered. In this case, the computer 13 is connected to the bar speaker 5 via a line 59 as shown in FIG. 4 .

Furthermore, the signals from the individual measuring elements 9a to 9h can be individually fed into an evaluation unit which is not directly relevant for the control. For example each sliver can be monitored in such a way that certain conditions are fulfilled. Each measurement can thus be compared to a threshold to ensure that a sliver is present, or that the sliver reaches a minimum volume. If these conditions are not met, the drafting unit is stopped. Such additional functions may also be performed by computer 13 . The invention can be used especially for drafting devices like drafting machines, combing machines and the like.

Claims (9)

1. feeding the method that many ribbons (11) of giving a drafting system (1) are gone up location parameter, it is characterized in that, parameter (47a to 47h) on each bar (11a to 11h) individually and measuring is converted into a common measured value (58) of a plurality of ribbons then in the different distance of drafting system.

2. by the method for claim 1, it is characterized in that the parameter on the test point (48) is being tested in drafting system (A).

3. by the method for claim 2, it is characterized in that measured value is used to control drafting system, and after measuring, the proportional delay of speed of parameter and distance (A) and bar.

4. by the method for claim 3, it is characterized in that, measure distance, and the parameter of each bar is separately according to postponing from the distance of predetermined reference point and the speed of bar from a predetermined reference point (39) of drafting system (1) front.

5. by the method for claim 4, it is characterized in that another from reference point (39) to drafting system (1) all is identical apart from (B) to whole bars (11), and whole parameters or measured value can one be reinstated a common delay consider.

6. implement the device by the method for claim 1, it is characterized in that, the inlet measurement mechanism has a plurality of measuring cells (9) corresponding with bar and a computer that is connected with these measuring cells (13).

7. by the device of claim 6, it is characterized in that the bar (11a to 11h) of every feeding has disposed a measuring cell (9a to 9h).

8. by the device of claim 6, it is characterized in that each measuring cell (9) is connected with computer (13) separately.

9. by the device of claim 8, it is characterized in that this computer is connected with a servo drive (19) of drafting system (1), so that measured value is sent to this servo drive.

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