EP1440193B1 - Yarn processing system - Google Patents

Description

The invention relates to a yarn processing system according to the preamble of patent claim 1.

For initial setup or after a change to a different thread quality (Style Change), the nominal thread tension profile must be adjusted for the entry cycle. A thread tension nominal profile is selected which ensures an optimum insertion frequency and insertion speed with the fewest yarn breakages possible for the respective yarn quality. The thread tension is affected by many parameters, such as the withdrawal tension from the yarn feeding device, the braking effect of the yarn brake, the nature and function of the entry device of the textile machine, the thread quality, and the like.

For the resulting thread tension profile and characteristics of the thread are crucial as its friction behavior, diameter, elasticity or density. These parameters require certain settings on, for example, the thread tension affecting braking devices. Deviations from the set yarn tension profile that require compensation may occur over time during operation of the yarn processing system, for example due to different supply spool diameters, fluctuating yarn characteristics and differently wound supply spools. For obvious reasons, the textile machine should process the thread as fast as possible. With weak threads, the strength of the thread sets a limit. If the machine speed is increased beyond a critical limit, the number of thread breaks increases exponentially. By means of a controlled yarn brake, the highest voltage peaks caused by high insertion speeds can be reduced, so that the voltage remains in particularly critical phases of the entry at low values. For this purpose, there are already high quality, controllable and adjustable thread brakes. Their precise adjustment is difficult, so in practice they have only a limited positive influence on the processing efficiency in the yarn processing system. Only with the information about the actual voltage or the actual voltage profile during an entry cycle can controlled thread brakes be set optimally. The information for thread tension can be obtained with the Tensiometer. However, the tensiometer means an additional yarn friction angle when measuring the yarn tension. However, for weak filaments, this additional friction angle caused by the tensiometer can be a disaster because the tension added by the tensiometer dramatically increases the likelihood of filament breakage so that a tensiometer can not be used in continuous operation of the filament-processing system for weak filaments. However, in the adjustment phase until the setting of the optimum nominal yarn tension profile, this disadvantageous influence of the tensiometer on weak threads is tolerable. On the other hand, stronger threads, which are processed with a controlled thread brake, tolerate the damaging influence of the tensiometer without increasing the probability of thread breaks even in continuous operation.

It is known to use a portable tensiometer, which is held in the thread path, measures the thread tension, and possibly. Indicates in a laptop. The tensiometer is used for a number of picking cycles representative of adjusting the nominal yarn tension profile to adjust, for example, the take-off tension from the yarn feeder, the brake level or yarn brake timing, and the like. During this adjustment phase yarn breaks or other disturbances can occur, until finally the optimal nominal yarn tension profile is found and established.

EP 0 357 975 A discloses a yarn processing system in which a controlled yarn brake is operated by means of a tensiometer permanently placed in the yarn path. Although the permanently operating in its detection position tensiometer would allow Einjustieren an optimal thread tension setpoint profile, but its influence is disadvantageous because of the additional Fadenumlenk- and friction point with weak yarn qualities.

EP 0 605 550 A discloses a yarn processing system in which a tensiometer is permanently assigned to a controllable yarn brake and can be switched between a passive position and a detection position. Since the tensiometer is only temporarily switched to the detection position during each entry cycle, namely, only with simultaneous work of the thread brake, no information about the thread tension is available if the thread brake does not brake. The tensiometer can measure, so to speak, only a limited section of the thread tension profile during an insertion cycle. However, to adjust the optimum nominal tension of the thread tension, the development and course of the thread tension over the entire insertion cycle is required.

The invention has for its object to provide a yarn processing system of the type mentioned above, which allows for different yarn qualities high insertion speeds with minimal yarn breakage rate.

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

Once the tensiometer is switched to the detection position, it monitors the development and course of the thread tension throughout the insertion cycle. The tensiometer remains in the detection position for a representative number of picking cycles, typically over approximately 50-100 picking cycles, until the optimum thread tension setpoint profile is adjusted by varying the parameters affecting the thread tension which ensures a minimum number of yarn breaks at optimally high picking speed. With strong yarn qualities, the tensiometer can remain in the detection position after adjustment to continue to provide permanent information about the thread tension, strong yarn qualities tolerate the additional friction by the tensiometer. However, since the tensiometer can optionally be changed back to the passive position, the optimum nominal thread tension profile can also be adjusted for weak yarn qualities, possibly with disturbances caused by the tensiometer, which, however, after the tensiometer has been returned to its passive position, at an optimally high picking speed guarantees a minimum thread breakage rate. The short period of time over which the weak thread has to handle the extra friction does not signify a significant reduction in the efficiency of the textile machine. If the tensiometer is held in the detection position with strong thread qualities, new settings of the parameters can also be made during continuous operation, eg on the controllable thread brake, if, for example, the thread breakage rate should have increased as a result of the above-mentioned influences. In the case of a non-controlled thread brake, the tension measured by the tensiometer in its detection position can be used by means of graphical or numerical representations to manually adjust the brake level of the thread brake.

Conveniently, the convertible tensiometer is associated with a thread brake that operates with an adjustable brake level consistent with the picking cycle to change the brake level until the optimum desired line tension profile is found, or a controllable thread brake that varies its braking action during the same picking cycle. With the information of the tensiometer, the timing and / or the braking level of the controlled yarn brake can be adjusted.

The tensiometer is advantageously connected directly to an adjustment device of the thread brake, so that feedback is used in a closed control loop. In this case, a computerized control device or brake level adjustment of the thread brake is suitable, which optionally responds to the measured thread tension corrective.

In a simple embodiment, the tensiometer or at least the element acting on the thread during measurement can be manually or mechanically converted. A manual change can be made by direct attack on the tensiometer or the element. A mechanical changeover takes place, for example, with the aid of a spring, which automatically switches the tensiometer to the passive position after the representative number of entry cycles triggered by a timer or a program.

Advantageously, the tensiometer or the element acting on the thread is connected to a Umstellaktuator, preferably an electromagnet or an electric motor, which receives, for example via a timer or programming, the command to produce the passive position of the tensiometer after the representative number of entry cycles.

Convenient handling is achieved when the tensiometer has a display device for the measurement results, preferably with graphical and / or numerical representation.

Since the tensiometer is permanently arranged in the thread path, it is expediently connected to the control panel of the textile machine, so that it can not only be changed over from the control panel, but its measurement results can also be recorded there if necessary. It is helpful if the display usually provided in the control panel can also be used to display the measured yarn tension.

It is advantageous to connect the tensiometer to an automatic changeover control device, e.g. after the representative number of entry cycles, the tensiometer is switched to the passive position and also provides the correct detection position of the tensiometer.

In order to minimize the influence of the tensiometer in its detection position for the thread, the tensiometer is structurally combined with the thread brake, preferably using at least one Fadenumlenkstelle the thread brake for the measurement.

The tensiometer can also be arranged upstream or downstream of a yarn detector, preferably a weft detector of a weaving machine, and is then advantageously even structurally combined with the weft detector, preferably using at least one yarn deflection point of the weft detector for the measurement.

Particularly expediently, the tensiometer can be converted into a plurality of different, eg thread quality-dependent, detection positions, which differ, for example, by their respective thread deflection angles. Because heavy thread qualities require a smaller friction angle than a light thread quality for a correct tension measurement.

In order to obtain correct measurements despite the different detection positions, it is expedient to provide an electronic measurement evaluation device which has an automatic compensation circuit for the different detection positions in order to compensate the then different parameters, wherein at least one position sensor is provided for the respective detection position, which is connected to the evaluation device. In the different detection positions, there are different force triangles during the measurement. These different force triangles would affect the measurement parameters and falsify the measurements. However, the evaluation electronics can select the correct parameters with the information of the position sensor and ensure correct measurements regardless of the respective detection position.

In the event that the yarn processing system has a plurality of yarn channels, each of which is fed by at least one yarn feeding device, a Tensiometer is expediently permanently provided in each yarn channel and umstellbar to set the same or even possibly an individual, optimal yarn tension profile for each yarn channel ,

The invention is applicable to all types of looms and knitting machines. The advantage is given to a yarn processing system whose textile machine is a rapier or projectile weaving machine, although a jet loom is also suitable. In knitting machines, different machine types may be involved, such as circular knitting machines or flat knitting machines or the like.

Fig. 1

schematisch eine Seitenansicht eines fadenverarbeitenden Systems mit einer Webmaschine,

Fig. 2

ein Detail als Variante zu Fig. 1,

Fig. 3

ein weiteres Detail als Variante zu Fig. 1,

Fig. 4

ein Detail als weitere Variante zu Fig. 1, und

Fig. 5

ein Fadenspannungs-Sollprofil.

Reference to the drawings, embodiments of the subject invention will be explained. Show it:

Fig. 1

schematically a side view of a yarn processing system with a weaving machine,

Fig. 2

a detail as a variant to Fig. 1,

Fig. 3

a further detail as a variant to FIG. 1,

Fig. 4

a detail as a further variant of Fig. 1, and

Fig. 5

a thread tension nominal profile.

A yarn processing system S in Fig. 1 comprises at least one yarn feeding device F, which is associated with a channel K1 a textile machine M and the textile machine M delivers a yarn Y. The yarn Y is removed from a yarn package L, cached in the yarn feeding device F on a storage body 1 and entered along a yarn path through an entry device E in the textile machine M. The textile machine M in FIG. 1 is a weaving machine, in particular a projectile or rapier weaving machine, but could also be a jet loom. Alternatively, the weaving machine can also be a knitting machine.

In the case of a weaving machine as a textile machine M are in the thread path downstream of the yarn feeder F a yarn brake B, downstream of the same permanent Tensiometer T, downstream of the same optionally a weft detector D and subsequently arranged the entry device E, of which the yarn Y in by a control device CU the weaving machine certain entry cycles are entered intermittently in a shed 8 and struck by a reed, not shown. The control device CU of the loom includes an unspecified control panel with a display G.

In the case of a projectile or rapier weaving machine the storage body 1 of the yarn feeding device is associated with a trigger brake 2, which generates a certain, relatively constant base tension in the yarn Y when deducted. In the case of a jet loom no trigger brake 2 is provided, but a stop device, not shown, which carries out the length measurement of the weft threads.

The yarn brake B has an adjustment device 3, with which the brake level (the braking force) can be adjusted to produce in the yarn Y between the entry device E and the yarn brake B a desired yarn tension when deducted. In the case of the thread brake B, stationary thread guide elements 5 are optionally provided.

Dashed is indicated in Fig. 1 as a possible alternative, a controlled yarn brake B with a control device 4. This means that the controlled yarn brake B, e.g. is activated and deactivated in response to control signals during each enumeration cycle by the control device CU to vary the braking effect during the same enumeration cycle and / or to switch between non-braking and braking phases.

The weft detector D registers the movement of the withdrawn yarn Y and generates a disturbance signal if no movement is detected in a phase during which a movement of the yarn Y is to be expected.

In the case of a rapier or projectile weaving machine, the insertion device E has a thread selector which selects the thread Y to be inserted from one of possibly several thread channels and assigns it to the entry element which inserts the thread into the shed 8 before it is struck and cut by the reed , In the case of a rapier weaving the yarn Y is taken at the entry end of the shed by a Bringergreifer and transported approximately to the middle of the shed 8, then handed over to a gripper rapier, and brought by this completely through the shed 8. In a projectile weaving machine, a projectile is shot through with each weft thread. In the case of a jet loom, the entry device E has at least one main nozzle and optionally additional nozzles in the shed 8 in order to register the yarn Y with air jets.

The yarn processing system S has downstream of the yarn brake B the permanently installed tensiometer T, which (or its thread Y acting element P) can be switched between a passive position (dashed), in which the yarn Y is not acted upon, and at least one detection position ( in solid lines) in which the yarn Y is deflected and rubbed to measure the yarn tension. The deflection takes place, for example, in relation to stationary Thread guide elements 5. The Umstellbewegung is indicated by a double arrow 6. The tensiometer T has a display 7 for the measured voltage, wherein the thread tension can be displayed graphically and / or numerically in shape. Dotted is indicated that the tensiometer T is connected to the control device CU or the control panel of the textile machine. Then, the display G can be shared to indicate the measured voltage, or the input devices in the control panel, to operate and optionally adjust the tensiometer.

The tensiometer T can be arranged at various positions, as indicated by the arrows a, b and c.

The tensiometer T is used to adjust or establish an optimal nominal yarn tension profile (a tension curve over the entry) for the picking cycles, which ensures the least yarn breakage rate at the optimum entry speed into the textile machine. Using the example of a rapier weaving machine, the nominal yarn tension profile is shown schematically in FIG. The adjustment of a nominal yarn tension profile is carried out, inter alia, during initial startup or after a change of the processed yarn quality, or if the quota of yarn breaks should accumulate during operation of the yarn processing system. The adjustment can be done manually to components of the thread processing system which are decisive for the thread tension, or also automatically in at least one closed loop with feedback. To adjust with the tensiometer located in the detection position, a sequence of entries is carried out, typically 50-100 entries, in order to set the parameters influencing the thread tension profile. In the case of a strong yarn Y, the tensiometer T remains in the detection position after the adjustment. He may then optionally be used to control the controllable yarn brake B and the like. In the case of weak or sensitive thread material, the tensiometer T is switched to the passive position after the adjustment phase, so that it no longer exerts any influence on the thread Y. The option of being able to selectively bring the tensiometer T or its element P acting on the thread into the passive position, if this is expedient for the processed thread material, however, the tensiometer in the Detection position to leave, if the thread material easily tolerates the additional friction and deflection by the tensiometer, is an essential feature of permanently provided in the thread path tensiometer T. Has the textile machine M multiple thread channels, then in each thread channel between a passive position and at least one Detection position provided convertible Tensiometer.

In Fig. 2, a manually convertible tensiometer T is recognizable, the element P acting on the thread adjustable mounted in a guide 9 and between stops 10 back and forth adjustable, which define the passive position I and a detection position II. For switching, for example, a hand lever 11 is provided, which can be performed by hand in the direction of the double arrow 6, the adjustments. As an alternative, not shown, the tensiometer could be acted upon by a spring in the direction of the passive position and held by a latch in the detection position. A control device, not shown, e.g. a timer or program, release the lock after the representative number of entry cycles required for adjustment so that the tensiometer T is then automatically switched to the passive position.

In Fig. 3, the tensiometer T is connected to an actuator A, which performs the Umstellbewegungen (double arrow 6). The actuator may be an electromagnet or an electric motor. According to FIG. 3, the tensiometer T or its element E acting on the thread has not only one detection position II, but at least one further detection position III. In the two detection positions II and III different thread deflection angles result. The actuator A can be controlled from the control panel of the weaving machine to set the desired detection position, or directly on the tensiometer T. For switching the tensiometer T, for example, back to the passive position I, a timer or a programming Z may be provided, which Changeover after performing the representative number of entry cycles.

FIG. 3 shows a control unit C of the tensiometer T in which a measurement result evaluation device 11 (computerized circuit with a microprocessor) is shown. is included, and optionally a compensation device 12, which takes into account the different force triangles in the different detection positions II and III, to still be able to provide correct measurement results. The control device C of the tensiometer T can be connected to at least one position sensor 13, which registers the respectively assumed detection position II or III and informs the control device C accordingly for compensation.

In order to introduce as little additional friction and deflection into the thread, the tensiometer T can be structurally combined with the yarn brake B or the detector D. For example, referring to Fig. 4, the tensiometer T utilizes a yarn guide element 14 of the detector D as a stationary deflection point relative to the element P. The yarn guide element 14 is, for example, a piezoelectric element that responds to yarn movement. A similar structural combination could also be provided with the thread guide element 5 downstream of the yarn brake B.

The operation of a rapier weaving machine results in a typical yarn tension profile (similar to a heart curve). Fig. 5 illustrates the yarn tension (in grams g) over a picking cycle (rotation angle of the main shaft of the loom). The thread is under a certain base tension, caused by the trigger brake 2 and the thread brake B (if this is not a controllable thread brake, but has a basic setting of the braking level). After taking over the thread by the Bringergreifer results in the curve 15, a first, relatively sharp voltage increase 16 results. In the subsequent acceleration phase of the gripper rapier, the thread tension in the curve part 17 increases before it decreases again in the delay of the gripper rapier shortly before the transition phase in the middle of the shed. Then there is a certain thread tension (curve part 18), with which the thread is transferred to the gripper rapier, this thread tension is important to ensure a proper transfer. Subsequently, the gripper rapier accelerates, so that again a curve part 17 occurs with increasing thread tension, before the thread tension drops with the deceleration of the gripper rapier to a curve part 19. The then visible at 19 voltage variations resulting from the stop movement of Riets and the cutting of the thread. For the curve set when adjusting, it is important that the Curve parts 17 are relatively mild fail, and that in the curve part 18 is a certain voltage curve with a certain basic voltage.

In the detection position, the tensiometer T measures the thread tension downstream of the thread brake B. Based on the measurement result or the measurement results of the representative number of insertion cycles, the trigger brake 2 and the thread brake B and optionally the detector D can be adjusted such that the optimum curve 15 of FIG Fig. 5 shows. These settings can be made manually, or in a closed loop with unspecified automatic control devices, for example, guided via the control device C and / or the control device CU. In this way, the curve 15 is established. Once this is done, the yarn processing system S can begin its normal operation. In the case of a strong thread, which does not tend to break despite the action of the tensiometer, the tensiometer T remains in the detection position. This makes it possible to monitor the normal operation based on the measurement results and to make further adjustments or optimizations if necessary. In the case of a weak thread, however, the tensiometer T is adjusted to the passive position, so as not to influence the thread. At most, when irregularities occur or the thread breakage rate increases, or even regularly only for "checking", e.g. at every 100,000th entry, the tensiometer T can then be switched back into or into a detection position to make new adjustments.

The illustrated tensiometer operates on the thread deflection principle with the element P, which is set transversely to the yarn path relative to two stationary deflection points 5. However, other types of tensiometers may also be used, for example with a piezoelectric element or with a pivotable element P. The display 7 may be provided directly on the tensiometer. But it is also conceivable next to the display 7 or alternatively to use only the display in the display G of the control panel of the loom.

For the settings, for example, the trigger brake 2 or the thread brake B (possibly also of the detector D) can not be highlighted auxiliary devices be provided, which automatically perform the settings in a closed loop, guided by the measurement result of the tensiometer T.

Claims (14)

1. Yarn processing system (S), comprising at least one yarn feeding device (F) associated to a yarn channel (K), a textile machine (M) like a weaving machine or a knitting machine, a yarn brake (B) in the yarn path between the textile machine (M) and the yarn feeding device (F), which are brake (B) at least is adjustable, and a tensiometer (T) scanning the yarn (Y) downstream of the yarn brake (B) at least for measuring the yarn tension (g), characterised in that the tensiometer (T) is provided permanently at the yarn path and is switchable between a passive position (I) and at least one detection position (II, III), and that the tensiometer (T) selectively can be switched from the respective detection position (II, III) in to the passive position (I) after a number of insertion cycles have occurred which number is representative at least for the adjustment of a yarn tension target profile (15).
2. Yarn processing system as in claim 1, characterised in that the switchable tensiometer (T) is associated either to a yarn brake (B) which has a constant but adjustable braking level during the insertion cycle, or to a yarn brake (B) the braking level of which is controllable during the insertion cycle, respectively.
3. Yarn processing system as in claim 1, characterised in that the tensiometer (T) is connected to an adjustment device (G), preferably to a computerised control device or braking level adjustment device of the yarn brake (B).
4. Yarn processing system as in claim 1, characterised in that the tensiometer (T) or at least an element (P) of the tensiometer which engages at the yarn (Y) during a measurement is manually or mechanically switchable.
5. Yarn processing system as in claim 1, characterised in that the tensiometer (T) or at least an element (P) of the tensiometer which engages at the yarn during the measurement is connected to a switchable actuator (A), preferably to an electromagnet or to an electric motor, respectively.
6. Yarn processing system as in claim 1, characterised in that the tensiometer (T) is provided with an indication device (7, G) for the measurement result or the measurement results, respectively, preferably for a graphical and/or numerical depiction.
7. Yarn processing system as in claim 1, characterised in that the tensiometer (T) is connected with the operation panel (G) of the textile machine (M), preferably also to a display provided on the operation panel.
8. Yarn processing system as in claim 1, characterised in that the tensiometer (T) is connected to an automatic switch over control device (C), in which, preferably, a time (Z) or program is provided for the duration of the detection position (II, III).
9. Yarn processing system as in claim 1, characterised in that the tensiometer (T) is structurally combined with the yarn brake (B), preferably by using at least one yarn deflection location (5) of the yarn brake (B) for the measurement.
10. Yarn processing system as in claim 1, characterised in that the tensiometer (T) is arranged upstream or downstream of a yarn detector (D), preferably of a weft yarn detector of a weaving machine.
11. Yarn processing system as in claim 10, characterised in that the tensiometer (T) is structurally combined with the weft yarn detector (D), preferably for using at least one yarn deflection location (14, 5) of the weft yarn detector for the measurement.
12. Yarn processing system as in claim 1, characterised in that the tensiometer (T) is switchable into several, different, e.g. yarn quality depending, detection positions (II, III), which differ, preferably, by their respective yarn deflection angles.
13. Yarn processing system as in claim 12, characterised in that an electric measurement evaluation device (C) is provided for the tensiometer (T), preferably comprising an automatic compensation circuitry (12) for measurement parameters associated to the different detection positions (II, III), that at least one position sensor (13) is provided for the respective detection position (II, III) of the tensiometer (T) or of the element (P) of the tensiometer which engages at the yarn during the measurement, and that the position sensor (13) is connected to the evaluation device (C, 12).
14. Yarn processing system as in claim 1, characterised in that several yarn channels (K) are provided, each being supplied with yarn by at least one yarn feeding device (F), and that a tensiometer (T) is provided in each yarn channel.

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