WO2006058776A1 - Method for operating a thread processing system - Google Patents

Abstract

The invention relates to a method for operating a thread processing system comprising a textile machine and at least one thread delivering device which comprises an electric speed control device (CU) and sensor devices (S1,S2) for detecting thread speed and momentary winding speed, wherein a blocking state of the thread delivering device can be detected by the speed control device (CU) and a stop signal can be produced or transmitted in order to disconnect the system with a delay time which can be determined at least by means of quotient calculation upon detection of a blocking state. According to the invention, the amount of the momentary thread supply (S) in the thread delivering device (F) is initially determined and the delay time (D) is calculated inversely in proportion to the quotient from the momentary thread delivery speed (V) and amount of momentary thread supply (S).

Description

 Method of operating a yarn processing system

The invention relates to a method according to the preamble of patent claim 1.

In a method known from US Pat. No. 4,002,044 A for knitting thread delivery in a circular knitting machine, stepwise fixed delay times for a higher-level control device are set with a control cam of a mechanical detection device for a blocking state. Depending on the rotation of the control cam, the control device activates the shutdown of the system, such that after a first short delay time no shutdown occurs, but only after elapse of a second longer delay time. Since the respective control cam used in its geometry according to a function of the nature of the thread, i. The thread quality is calculated, must be used consistently when changing the system to a different thread quality another control cam. The basic definition of the respective delay time depending on the nature of the thread material is a compromise, i.e. the system may be switched off more frequently than it would actually require. The purpose of the delay time is namely to offer the yarn feeder the ability to automatically fix the blocking condition, which is due to an increased withdrawal resistance of the thread from the thread supply or the occurrence of a loop or the like., So that then immediately a normal Aufwickelprozedur possible is, and in the meantime continue working circular knitting machine no knitting error is generated.

In a method known from EP 1 391 983 A, the delay time until shutdown of a weaving machine is determined by a quotient calculation by dividing a predetermined constant either by the synchronization frequency for speed control of the drive motor of the yarn feeding device or by the determined average yarn feeding rate. Accordingly, taking into account maximum and minimum limits of the delay time, the delay time becomes the longer the lower is either the synchronization frequency or the average yarn feed rate. Since the size of the current yarn supply in the yarn feeding device fluctuates according to consumption, the result of this quotient calculation with a fixed constant as a counter no optimally long delay time. Because a small thread supply would be consumed faster with the average yarn delivery rate than a large thread supply, which must be taken into account when calculating the delay time, for example in the constant. This requires that the constant as a numerator of the quotient is relatively large and therefore safe to predict, in order to compensate for the size of the thread supply, which sometimes fluctuates greatly during weaving. As a result, the system is already switched off, although actually could be maintained even longer, to allow the drive of the yarn feeder to still eliminate the blocking condition. Especially in knitting machines, especially circular knitting machines, it is desirable to delay the shutdown of the system as long as possible and yet safe, only to switch off when there is no longer any possibility that the yarn feeding device can automatically eliminate the blocking state, but without the yarn supply completely eat up and avoid thread breakage. Because with circular knitting machines, it can already result from switching off and restarting goods defects that can no longer be eliminated.

The invention has for its object to provide a method of the type mentioned above, with which the system is switched off optimally late, if the yarn feeding device is not able to eliminate the blocking state automatically.

The stated object is achieved with the features of claim 1.

Since the sensor devices, which detect the yarn delivery speed and the take-up speed, in any case provide information about wound and unwound yarn turns, this information is used to determine the size of the current yarn supply in the yarn feeding device. Once a blocking state of the yarn feeding device is detected, for example, due to the hooked on the supply reel thread or because of a imposed loop or a node, the delay time is calculated inversely proportional to the quotient of the current thread delivery speed and the size of the current thread supply in the quotient calculation. The delay time thus becomes longer, the greater the current thread stock is at a given yarn delivery speed or the shorter, the smaller the current thread stock is. The delay time is adaptively determined in each case such that the thread supply is consumed within the delay time at most until, for example, a few full turns of thread, if the blocking state can not be eliminated by the yarn feeding device within the delay time. If expediently the calculation is repeated continuously, even the delay time can always be adapted to changing conditions, ie to an increasing or decreasing size of the current thread supply and / or to an increasing or decreasing instantaneous yarn delivery speed. This adaptive calculation of the delay time is particularly useful for a yarn feeding device of a knitting machine, especially a circular knitting machine, because there the yarn delivery speed does not vary drastically, as is the case for example in a weaving machine, and because the yarn feeder the possibility of an automatic elimination of the blocking state as long as possible to be kept open in order to avoid the loss of production after switching off the system and especially knitting errors in the fabric, which, unlike a weft thread error during weaving can hardly be eliminated.

In an expedient variant of the method, the delay time is calculated at least at an instantaneous take-up speed below the maximum take-up speed of the yarn feeding device. This is an operating phase in which the delay time due to the low take-up speed must be calculated very accurately taking into account the size of the current thread supply. Runs the yarn feeding device with the maximum winding speed, which can be tuned in advance to the maximum expected thread delivery speed, there are relatively clear conditions and, if necessary. A small size of the yarn supply, so that then optionally a fixed delay time can be considered.

In a suitable method variant, the delay time is calculated taking into account at least one thread feed device-dependent constant. This constant can take into account, for example, the acceleration or deceleration behavior of the drive motor of the yarn feeding device, which is important for the supplement of the thread supply after removing the operating condition. In another advantageous variant of the method, the delay time is calculated taking into account at least one thread quality-dependent constant, because the load capacity of the thread material is decisive for how long, for example, the yarn feeding device may be allowed to eliminate the blocking state automatically by tensile load of the thread.

In a further expedient variant of the method, the delay time is calculated taking into account a predetermined safety factor, for example in order to still have enough thread material for a comfortable repair in the thread supply after the delay time, or to avoid an unacceptable increase in the thread tension in a knitting machine, or one during the Calculation not yet known increase the yarn delivery speed to compensate. The safety factor may e.g. be determined empirically, taking into account the known fluctuations either the yarn delivery speed and / or the stock size.

Suitably, the maximum delay time is set so that from the detection of a blocking state of the current thread supply is currently not completely consumed with the current thread delivery speed. This facilitates the subsequent repair.

Conveniently, even when a blocking condition is detected, the tensile load in the thread is increased slightly to try to release the blocked thread or a loop. This can e.g. occur briefly and programmatically, for example, by the boost-like torque for the rotor is increased. Boosting significantly increases the likelihood of automatic troubleshooting.

An embodiment of the subject invention will be explained with reference to the drawings. Show it:

Fig. 1 is a yarn delivery device in a yarn processing system, and 2 shows a diagram of a quotient calculation (yarn supply size over the yarn delivery speed).

As an example of a yarn processing system X in Fig. 1, a knitting machine 8, for example, a circular knitting machine, shown schematically, the at least one yarn feeding device F is assigned, which supplies a yarn Y. However, a non-shown other yarn processing system could also include a loom or other yarn processing machine having at least one yarn feeding device.

The yarn feeding device F has a housing 1, in which an electric motor M with a rotor R and an electronic speed control device CU (motor controller) are arranged. The rotor R drives a rotatably mounted winding element 2 in relation to a coaxial, stationary and drum-like storage body 3, on the outer circumference of the yarn Y is cached in a thread supply S in adjacent turns 6 for deduction. Alternatively, however, the yarn feeding device F could also have a rotatable storage body driven by the motor M.

In the illustrated embodiment of the yarn feeding device F, the storage body 3 is assigned a yarn control element, for example a yarn brake 4. The yarn Y is pulled from the yarn supply 6 with a pointer-like circumferential movement over the free front end of the storage body 3 through a trigger eye 9 and then into the knitting machine 8, for example in a knitting system of a circular knitting machine. The trigger 9 is housed in a housing boom 5. A sensor S2, for example an optical sensor, is provided in the area of the withdrawal eye 9 for detecting the yarn delivery speed, for example by means of one or more pulses per withdrawn yarn winding 6. The wind-up element 2 is assigned a further sensor S1, eg a Hall sensor which detects the take-up speed. eg based on at least one pulse per revolution of the take-up element. 2 The speed control device CU includes, for example, a microprocessor P and a timer T and is operatively connected to the motor M and the two sensors S1, S2.

The speed control device CU operates such that the electric motor M accelerates depending on the consumption of the thread by the knitting machine 8 to a predetermined maximum speed, and is delayed, possibly to a standstill, such that despite consumption in each case a yarn supply S of a predetermined size largely is maintained. At a relatively constant yarn delivery speed, the speed of the electric motor M using the influence of the speed control device CU levels to a speed level that corresponds approximately to the consumption rate. Variations in consumption follows the electric motor M with a system-related delay, so that even with relatively constant consumption, the size of the yarn supply S varies.

In order to control the electric motor M as a function of consumption in such a way that there is always a sufficiently large yarn supply S, the speed control device CU takes into account the signals of the sensors S1, S2 in order to derive therefrom speed signals for the electric motor M. For example, the speed control device CU calculates the magnitude of the currently existing yarn supply S from the signals from the sensors S1, S2, compares this quantity with a desired quantity, and accelerates or decelerates the electric motor M in the event of deviations. -

The size of the thread supply S can be recorded as the number of turns 6 on the storage body 3, the circumferential length is known, or directly as a thread length, for example, in centimeters. The take-up speed of the take-up element 2 and thus of the yarn Y can be taken into account, for example, as speed or number of pulses per unit of time, while the yarn delivery speed is expressed, for example, as a number of pulses per time unit or directly as a speed, e.g. cm / s, or is considered as the number withdrawn turns of thread 6 per unit time.

During operation of the thread-processing system X, the thread Y may be imposed on the supply reel 7, or a knot or shoe may be present. ge imposed or hanging along the Fadeπwegs to the storage body 3 of the yarn feeding device F remains. The then increasing trigger resistance of the yarn Y can block the rotor R, which no longer rotates, or can not be accelerated from standstill. Such a blocking condition would, if it persists longer, forcibly lead to a thread break, whereupon the system X must be shut down so that no error occurs in the product. Especially when knitting a free thread end should be withdrawn after a thread break, because this knitting error can not be resolved. But even a strong increase in tension in the thread in the knitting system would result in a no longer be eliminated knitting error. Switching off the knitting machine 8, in particular a circular knitting machine, not only means a loss of production, but can also lead to irregularities in the product when stopping and restarting. Therefore, one strives to turn off the system S only if a knitting error can not be avoided otherwise.

In practice, especially when knitting, but also during weaving, it is sometimes found that the tensile load generated by the blocked rotor in the yarn Y is sometimes sufficient to loosen the imposed yarn Y on the supply reel 7 or to detach or dislodge a imposed sling whereupon the rotor can immediately continue its rotation of the control routine. On the storage body 3, in any case, the thread supply 6 is present with a current size, which initially further ensures undisturbed delivery to the knitting machine 8. For these reasons, when a blocking condition occurs, the system is not immediately shut down, but a delay time is waited within which the yarn feeding device F is kept open the possibility of automatically overcoming the blocking state and resuming the normal buffering function. The delay should last as long as possible to maximize the likelihood of self-repairing the stall condition.

According to the invention, the highest possible probability of automatic correction of the blocking state is achieved by calculating and taking into account in the speed control device CU a delay time D which is indirectly proportional to the quotient of the size of the current yarn supply S and the current delivery speed V of the yarn Y is. This calculation is performed at least in an operating phase in which the instantaneous take-up speed (rotational speed of the takeup element 2) is lower than the predetermined maximum takeup speed).

Based on the signals of the sensors S1, S2, the speed control device CU is informed about simple calculation processes about what size the current thread supply S has, for example about the number of thread turns 6 or even the cached thread length in centimeters. From the size of the current thread supply S as a counter and the current thread delivery speed as denominator, the speed control device CU each calculates a delay time with which it is ensured that the thread supply S is not completely consumed within the delay time. At least some full turns of thread 6 should still be present on the storage body 3 after the lapse of the delay time in order to carry out the subsequent repair comfortably.

Here, two procedures are appropriate, without the invention should be limited thereto.

Once the blocking state has been detected, for example, by the winding element 2 having stopped even though the electric motor M is activated, a so-called stop-motion signal is generated, which is intended for a so-called stop-motion relay for switching off the system , However, the stop-motion signal is not immediately transmitted to the stop-motion relay, but is suppressed using the timer T until the calculated delay time has elapsed.

In the other case, the stop motion signal is generated only after the delay time monitored by the timer and immediately forwarded to the stop motion relay. If, on the other hand, the blocking state is automatically canceled within the calculated delay time, then the stop motion signal is either not generated at all or is not forwarded.

In the quotient calculation, a safety factor is expediently taken into account, for example a multiplier of less than 1, in order to ensure a certain residual quantity of the yarn supply S and, if necessary, to indirectly take into account unforeseeable changes in the yarn delivery speed.

Furthermore, it is possible to program the speed control device CU in advance with regard to the respectively processed thread quality, or the operating behavior in the system, or certain properties of the yarn feeding device F, so that in the quotient calculation a yarn feeding device-dependent constant factor and / or a thread quality-dependent constant factor or Like. Be considered or become, or thus boost-like in a blocking example the torque for the winding element 2, if necessary. For a short time, can be increased.

2 shows symbolically in a diagram the quotient calculation for the adaptive determination of the delay time D. On the vertical axis, the size of the yarn supply S is plotted, for example, in centimeters, while on the horizontal axis the yarn feed rate V is plotted, for example, in cm / s. The vertical axis also represents the time t, for example in seconds, while the horizontal axis also represents the winding speed n, for example in rpm. X

On the horizontal axis, a predetermined maximum winding speed nmax is indicated. For example, the dashed vertical line set to the left limits the range within which the quotient calculation is performed. D represents the resulting curve or delay time.

The curve shows that the delay time D is longer, the larger the yarn stock S and the smaller the yarn delivery speed V, and vice versa. The process according to the invention will be explained more clearly by way of example:

A current delivery speed of 667 cm / s (400 m / min), a size of the current yarn stock S of approximately 560 cm, and a safety factor of 0.9 are assumed. From the quotient calculation results then a delay time D of about 0.76 s. When the system is switched off, there is still a remaining length of 53 cm on the storage body 3, i. e.g. about three turns 6.

The inventive method is particularly useful for circular knitting machines, because there the yarn delivery speed fluctuates only moderately and therefore the consideration of the size of the current thread supply in the quotient calculation leads to the highest possible probability of automatic removal of the blocking state.

In the event that the thread processing system is equipped with a fast communication system, the calculation and consideration of the delay time for each blocked yarn feeding device could also be performed centrally in a main computer or the main control device of the system. The main computer or the main control device is informed about the current yarn delivery speed of the yarn feeding device and only needs the information on the size of the current thread supply:

Claims

claims 1. A method for operating a yarn processing system (X) comprising a textile machine, in particular a knitting machine (8) or a weaving machine, and at least one yarn feeding device (F), wherein the yarn feeding device (F) an electronic speed control device (CU) and Sensor devices (S1, S2) for detecting the yarn delivery speed and the current winding speed, wherein a blocking state of the yarn feeding device (F) detectable bar and a stop signal for switching off the system (X) after a determined by a quotient calculation delay time from detection of a blocking state is generated or passed on, characterized in that the size of the current yarn supply (S) in the yarn feeding device (F) is determined, and that the delay time (D) inversely proportional to the quotient of the current yarn delivery speed (V) and the size of the current thread supply ( S) is calculated. 2. The method according to claim 1, characterized in that the delay time (D) at least at a current winding speed (n) below a predetermined maximum winding speed (n _max ) of the yarn feeding device (F) is calculated. 3: Method according to claim 1, characterized; the delay time (D) is calculated taking into account at least one threading device-related constant. 4. The method according to claim 1, characterized in that the delay time (D) is calculated taking into account at least one thread quality-dependent constant. 5. The method according to claim 1, characterized in that the delay time (D) is calculated taking into account a predetermined safety factor, preferably a multiplier less than 1. 6. The method according to claim 1, characterized in that the delay time (D) is calculated in each case so that from detection of a blocking state of the current thread supply (S) with the current thread delivery speed (V) is only consumed up to a few full turns of thread (6) , 7. The method according to claim 1, characterized in that upon detection of a blocking state preferably briefly, programmatically, the tensile load is increased.