WO1997040218A1

WO1997040218A1 - Device for opening a gripper clip of a mechanical loom gripper

Info

Publication number: WO1997040218A1
Application number: PCT/EP1997/001917
Authority: WO
Inventors: Henry Shaw; Ignace Meyns
Original assignee: Picanol N.V.
Priority date: 1996-04-19
Filing date: 1997-04-17
Publication date: 1997-10-30
Also published as: JP2000508722A; CN1216586A; KR20000005448A; EP0904437A1

Abstract

A device (1) for opening a gripper clip (2) of a mechanical loom gripper (3) has a stop element (4) arranged in the path of displacement (24) of a stopper (23) of the gripper clip (2) and whose position in the direction of displacement (A) of the gripper (3) can be adjusted by means of a drive (5) controlled by a control unit (6). The stop element (4) can slide in a guide in such a way that it can be moved out of the path of displacement of the stopper (23) upon a command from the control unit (6).

Description

Device for opening a rapier clamp of a rapier of a weaving machine

The invention relates to a device for opening a rapier clamp of a rapier of a weaving machine with a stop element which is arranged in the path of movement of a stop part assigned to the rapier clamp and whose position in the running direction of the rapier is adjustable by means of a drive controlled by a control unit.

In rapier weaving machines, a weft thread is usually pulled through a shed with the aid of a donor rapier and a slave rapier. The master gripper clamps a weft to be fed in a gripper clamp and brings it into the center of the shed from the insertion side. A device for opening the gripper clamp of the gripper is arranged on the entry side in the position in which the gripper picks up the weft thread. In the middle of the shed, the weft thread is taken over from the donor rapier by the picking rapier, clamped in a rapier clamp of the picking rapier and pulled by the picking rapier to the other side of the shed. In the middle of the shed, devices can be provided for opening the gripper clamp of the master gripper and / or the gripper clamp of the slave gripper. After leaving the shed, the slave gripper releases the weft. This is done on this page of the shed a device for opening the gripper clamp of the slave gripper is also provided.

A device of the type mentioned at the outset for opening a gripper clamp of a slave gripper is known for example from EP 0 309 700 AI. This device has a bar-shaped stop element which lies in the path of movement of a stop part of the slave gripper, which opens the gripper clamp against the strip-shaped stop element when it starts up. The strip-shaped stop element can be adjusted by means of a drive controlled by a control unit in order to adjust the distance of the point at which the looper clamp releases the weft thread to the shed or the selvedge to the operating conditions. In one embodiment, the strip-shaped stop element is adjusted in the running direction of the gripper by means of a piston / cylinder unit.

A device for opening a gripper clamp of a slave gripper that picks up the weft thread on the entry side and pulls it through the entire shed is known from US Pat. No. 2,837,124. For example, from FIG. 17 it can be seen that this device has a stop element which is arranged in the movement path of a stop part of the gripper clamp. This stop element has a run-on section, an intermediate section running essentially parallel to the running direction of the slave gripper, and an end section receding therefrom. When the taker gripper is pulled out of the shed and runs past the stop element, the stop part of a gripper clamp of the taker gripper comes into contact one after the other with the input section, the intermediate section and the end section, whereby the gripper clamp is opened, kept open and then ge again ¬ is closed. When the slave gripper is moved back into the shed, the stop part of the hook clamp of the slave gripper successively runs against the end section, the intermediate section and the input section. The position of the stop element in the running direction of the slave gripper is manually adjustable. The stop element is fastened on a rod which is arranged displaceably and fixably in a holder of the loom frame.

From JP-A 49-27662 a further device for opening a gripper clamp of a gripper pulling a weft thread through the entire shed is known, which has a stop element. The stop element consists of a bolt which can be manually adjusted by means of a mechanism in order to define the position in which the gripper clamp of the slave gripper is opened.

Another device for opening a gripper clamp of a slave gripper is known from JP-A 62-162049. In this type of construction, a stop element, which lies in the movement path of a stop part of the gripper clamp of the slave gripper, is arranged on a threaded spindle. The threaded spindle is driven by means of a drive controlled by a control unit in such a way that the stop element can be adjusted in the running direction of the slave gripper. Sensors are connected to the control unit, which transmit information about the inserted weft thread to the control unit, which adjusts the stop element by turning the threaded spindle in such a way that the hook clamp opens in a suitable position.

A device for opening a gripper clamp of a slave gripper is known from GB patent 1 460 145, which also has a stop element against which a stop part of the gripper clamp of a slave gripper runs. The strip-shaped stop element is held so that it opens the gripper clamp when the slave gripper is pulled out of the shed. If the slave gripper is moved into the shed, the stop element yields, so that the gripper clamp of the slave gripper is not opened. In a further known device according to US Pat. No. 3,927,699, it is also provided that the gripper clamp of the H

The slave gripper is only opened when the slave gripper runs out of the shed. However, if the slave gripper is moved into the shed, the stop part dodges so that the gripper clamp is not opened. In both types, the gripper clamp of the slave gripper is thus opened less frequently, which has an advantageous effect on the service life of the gripper clamp.

From EP-0 266 286 A2 a device is known which has stop elements for a slave gripper and for a master gripper which are pivotally mounted. The stop elements are moved out of the movement path of a stop part of the gripper clamp by means of a spring. They can be moved into the path of movement of the stop part of the gripper clamp by means of an electrical adjusting element against the action of the spring. The stop part of the encoder gripper only runs into the stop element when the encoder gripper is moved into the shed, while it passes the stop part moved out of the movement path without touching it when it is moved out of the shed again. In a corresponding manner, the stop element for the picker gripper is only moved into the movement path of the stop part of the hook clamp of the picker gripper when it runs out of the shed so that the hook clamp is opened to release the weft thread. When the slave gripper is moved into the shed, the stop element is pivoted so that the stop part of the gripper clamp of the slave gripper passes the stop element without touching it. This not only reduces the frequency of opening and closing the gripper clamps of the master gripper and the slave gripper, but also the frequency of contact between the stop part of the gripper clamps and the stop element. This has a favorable effect on the service life of the stop element and on the service life of the stop part of the gripper clamp of the slave gripper and the encoder gripper. A device is known from US Pat. No. 4,655,263, in which a rod-shaped stop element can be adjusted by means of a drive derived from the main drive of the weaving machine in order to change the position in which the gripper clamp of the master gripper closes and clamps a weft thread. In this type of construction, the picking gripper is presented with a weft thread from a multiplicity of ready-made weft threads, which are each taken over by the picking gripper at different points. By displacing the stop element, it should be achieved that each of the weft threads that can be presented to the gripper is correctly picked up and clamped.

The invention has for its object to design a device of the type mentioned in such a way that not only the position can be set in which the gripper clamp of a gripper or slave gripper opens or closes, but also that the service life of the stop element and the The service life of the stop part of the gripper clamp and the service life of the gripper clamp itself can be extended.

This object is achieved in that the stop element is guided in a guide such that it can be moved out of the movement path of the stop part on command from the control unit.

The invention has the advantage, on the one hand, that the stop element can be set in a simple manner to determine the opening or closing position in the running direction of the gripper, while, on the other hand, the stop element can also be moved out of the movement path of the stop part of the gripper clamp of the gripper, so that the Grei.βarklemme less actuated and the wear can be reduced. The stop element is adjustable in such a way that it opens or closes the gripper clamp of a gripper in one direction of movement at a desired position of the gripper and during movement in the opposite direction Direction does not come into contact with the stop part of the gripper element.

In an advantageous development of the invention, it is provided that the stop element is adjustable in a guide which has at least one guide section extending in the running direction of the gripper and at least one guide section running obliquely thereto, the guide section moving out of the movement path of the stop part of the gripper clamp . Due to this design, it is possible to adjust the opening or closing position of the gripper clamp by adjusting the stop element in the at least one guide section extending in the running direction of the gripper, and by moving the stop element in the at least one oblique Guide section to move the stop element out of the path of movement of the stop part of the gripper clamp. This design also makes it possible not only to set the opening or closing position, but also to move the stop element out of the movement path of the stop part of the gripper clamp by means of only one drive.

In a further embodiment of the invention, an electric positioning drive controlled by the control unit is provided as the drive for the stop element. By means of such a positioning drive, each position predetermined by the control unit can be approached exactly in order to set the stop element in the desired position.

In a further embodiment of the invention it is provided that positions for the stop element that can be reached by means of the positioning drive are stored in the control unit, the properties of weft threads to be processed and / or the formation of the shed and / or operating states of the loom and / or operating parameters are assigned . This makes it possible to set known, suitable positions of the stop element for each weft insertion. In a further embodiment of the invention, it is provided that the stop element and the associated drive are arranged on a machine frame of the weaving machine by means of a common holder. The device thus forms a preassembled unit. It is expediently further provided that the holder is attached to the machine frame by means of an adjustment in the running direction of the gripper and / or fastening elements which permit it to run transversely to this running direction. This makes it possible to arrange the entire device in a pre-adjusted position, from which the desired positions of the stop element are then moved to by means of the drive. The adjustment paths of the stop element can therefore be relatively short.

In an advantageous embodiment of the invention it is provided that the stop element can be adjusted relative to the holder by means of the positioning drive, wherein guide elements are provided between the holder and the stop element, which guide elements have at least one straight guide section and at least one inclined to it Define the management section. In a simple embodiment it is provided that the guide elements are designed as guide slots and guide bolts guided therein. This results in a particularly simple implementation of the invention.

In a further embodiment of the invention, it is provided that the adjustment path of the positioning drive is limited to a length that is shorter than the length of the slots. In this way it is prevented that the guide bolts run against the ends of the slots when the stop element is moved out of the movement path of the stop part of the gripper clamp. This not only prevents noise, but also reduces wear. Q

In a further embodiment of the invention it is provided that switching means for switching the positioning drive on and off are arranged in the region of the stop element. This makes it possible for an operator to control the movements and the positions of the stop element manually by switching the positioning drive on and off.

In a further embodiment it is provided that in the area of the stop element there are input means for entering set positions of the stop element and / or for correcting the set positions in the control unit. In this way it is possible for the operator to experimentally set suitable positions for the stop element and enter them into the control unit, which positions are then stored in the control unit so that they are then automatically started up. It is also possible, if positions to be approached are stored in the control unit, to correct them.

Further features and advantages of the invention result from the following description of the embodiments shown in the drawing.

1 shows a largely schematically illustrated view of a device according to the invention for a slave gripper,

2 shows a section along the line II-II of FIG. 1,

3 is a partially sectioned view in the direction of arrow III of FIG. 1,

4 shows a section along the line IV-IV of FIG. 3,

5 to 10 sections of the device according to the invention, similar to FIG. 4 with different positions of the stop element and the slave gripper, 3

11 shows a modified embodiment, similar to FIG. 1,

12 shows a modified embodiment of a device according to the invention in a first position,

13 shows the device according to FIG. 12 in a changed position of the stop element,

14 shows a section similar to FIG. 4 through a modified embodiment,

15 shows a section similar to FIG. 4 through a further modified embodiment,

Fig. 16 is a plan view of the embodiment of FIG. 1 with an additional device and

Fig. 17 is a view of an embodiment of FIG. 1 with a modified additional device.

The device 1 shown in FIGS. 1 to 4 for opening a gripper clamp 2 of a gripper, in the present case a gripper 3, of a weaving machine contains a stop element 4 which is adjustable by means of a controllable drive. This drive contains a positionable drive motor 5, for example a stepper motor or a servo motor, which is controlled by a control unit 6, for example the control unit of the weaving machine.

The drive motor 5 is fastened to a holder 7 by means of screws 8. This bracket 7 is attached to the frame 9 of the loom. According to the illustration in FIG. 2, the holder 7 works together with fastening elements in order to adjust the position of the holder 7 relative to the frame 9 of the weaving machine. These fasteners contain eccentric 10, which in an undercut longitudinal groove 11 of the Frame 9 of the loom are arranged. Furthermore, the fastening means contain screws 12, which are each screwed into a thread of the eccentric 10. By means of the fastening elements, the holder 7 can be fastened in a desired and adjustable position with respect to the frame 9. This position is adjustable both in the longitudinal direction of the groove 11 and transversely to it.

As shown in FIGS. 3 and 4, the stop element 4 is also held on the holder 7 and connected to the drive motor 5 by means of transmission means. A crank 13 is arranged on the motor shaft 14 of the drive motor 5 in a rotationally fixed manner, which crank or the like by means of a screw 15. is articulated to an intermediate rod 16. The intermediate rod 16 is also articulated via a screw 17 or the like. connected to the stop element 4.

3, 7 guide bolts 18 are attached to the holder. These guide bolts 18 have a thickened head, a cylindrical section and a threaded section which is smaller in diameter. The threaded section penetrates the holder 7 and is each provided with a nut 20 so that the guide bolts 18 are clamped to the holder 7. The guide bolts 18 hold the plate-shaped stop element 4 between their thickened head and a spacer sleeve 19. The stop element 4 is provided with slots 21 in which the cylindrical section of the guide bolts 18 is guided. The guide elements are preferably designed as two guide slots 21 and guide pins 18 guided therein.

As can be seen from FIGS. 1 and 4, the guide bolts 18 are arranged on a line essentially parallel to the running direction A of the slave gripper 3.

The stop element has a stop surface 22 which is connected to a stop part 23 of the gripper clamp 2 of the slave gripper 3 interacts. This stop surface 22 runs essentially parallel to the running direction A of the slave gripper. The stop surface 22 has a central section essentially parallel to the running direction A and chamfered end sections. The slots 21 each have a straight central section which runs at least approximately parallel to the direction of travel A of the slave gripper and parallel to the stop surface 22. This middle section is adjoined by two end sections which run obliquely to the middle section.

If the stop element 4 is adjusted by means of the drive motor 5 and the transmission elements 13, 16 to fix the opening of the gripper clamp 2, it is guided in the area of the middle section of the slots 21 parallel to the running direction A of the slave gripper 3. If the stop element 4 is adjusted so far that the oblique end sections of the tip 21 reach the area of the guide bolts 18, the stop element 4 is moved out of the movement path 24 of the stop part 23 of the gripper clamp.

1 and 4, the movement path 24 of the stop part 23 of the gripper clamp 2 is shown in dashed lines. The gripper clamp 2 is held in the closed position by means of a spring 27.

The movement path 24 of the stop part 23 of the gripper clamp 2 runs parallel to the running direction A of the slave gripper 3. As long as the middle section of the slots 21 of the stop element 4 receives the guide bolts 18, the stop surface 22 of the stop element 4 projects over the movement path 24 out to the stop part 23. However, if the guide bolts 18 are in the end sections of the slots 21, the stop element 4 is moved away from the movement path 24 in such a way that the stop part 23 runs past the stop surface 22 without touching it. As can still be seen from FIG. 2, the frame 9 of the weaving machine is provided with guides 25 for a rapier belt 26, to which the slave rapier 3 is attached.

The mode of operation of the device is explained below with reference to FIGS. 5 to 9.

If the slave gripper 3 is located in a shed, the drive motor 5 is controlled by the control unit 6 such that the stop element 4 is in a position according to FIG. 5 in which its stop surface 22 is in the movement path 24 of the stop part 23 the gripper clamp 2 protrudes. The control unit 6 brings the stop element 4 in the running direction of the take-up gripper 3 into a position which, for example for the weft thread 28 picked up by the take-up gripper 3, is stored in a memory of the control unit 6 and is called up for this weft thread 28. A plurality of predetermined positions are stored in the control unit 6, for example six positions which are assigned to the weft threads to be inserted in each case. The selection of the suitable positions depends on the weft 28, for example on the type of weft 28 and the feed path over which the weft 28 is fed. In addition, the selection of the position also depends on the type of shed into which the weft thread 28 is inserted, ie, for example, how often the weft thread 28 is clamped ^" between two adjacent warp threads, and for example also on the time at which these warp threads cross.

The slave gripper 3 is pulled out of the shed in the direction P, so that the stop part 23 of the gripper clamp 2 comes into contact with the stop surface 22 of the stop element 4 in the position shown in FIG. 6, so that the gripper clamp 2 is opened, as this is shown in Fig. 1. The slave gripper 3 then moves further in the direction P until the stop part 23 leaves the stop element 4 and the slave gripper 3 has reached the position shown in FIG. 7. Thereafter, the drive motor 5 is controlled by means of the control unit 6 in such a way that it brings the stop element 4 into one of the outermost positions (FIG. 8), so that the stop surface 22 of the stop element 4 is outside the movement path of the stop part 23 of the gripper clamp 2 ¬ det. The slave gripper 3, which is reinserted into the shed in the direction of arrow Q, then runs past the stop element 4 without the stop part 23 of the gripper clamp 2 touching the stop surface 22 of the stop element 4. Thereafter, the control unit 6 controls the drive motor 5 such that it brings the stop element 4 into a position which is assigned to the weft thread to be inserted next. This position can again be the position that the stop element 4 has assumed in FIG. 5, for example. However, it can also be a different position depending on the weft thread and / or on the formation of the shed, for example the position 4A, which is dashed in FIG. 5.

The position in which the stop element 4 is when the stop part 23 of the gripper clamp 2 of the slave gripper 3 comes into contact with the stop element 4, ie the position shown in FIGS. 5 and 6, is determined by the control unit 6 , in which suitable positions are stored which are suitable for the weft thread 28 to be introduced and / or the shed formed. The point in time at which a weft thread 28 is released by the gripper 3 is essential for the weft length and the stretching with which a weft thread 28 is woven. For this reason, the positioning of the stop element 4 takes place essentially as a function of the type of weft thread introduced. Since a thick weft thread is only released by the slave gripper 3 when the gripper clamp 2 is opened further, the gripper clamp 2 must open earlier in this case. For this purpose, the stop element 4 is positioned closer to the shed. Elastic weft threads can spring back into the shed after being released so that loops form in the shed the. Elastic weft threads should therefore be released later by the gripper clamp 2, ie at a point in time at which these weft threads 28 are clamped more strongly between the warp threads. Accordingly, the stop element 4 is positioned further away from the shed. In a similar manner, weft threads 28, which are slowed down considerably in their feed path by thread brakes and therefore have a high tension, should be released later from the gripper clamp 2. The clamping of the weft threads between the warp threads plays an important role, so that the positioning of the stop element 4 also takes place depending on the formation of the shed into which the weft thread in question is inserted. In the case of bindings in which a plurality of warp threads lying next to one another intersect and thus the weft threads jam relatively strongly, the weft thread must be released from the gripper clamp earlier than in the case of bindings in which fewer adjacent warp threads cross. In the case of weaves in which the warp threads cross earlier in the weaving cycle, the weft thread can be released earlier from the hook clamp 2 than in the case of weaves in which the warp threads are crossed later. Taking these conditions into account, a suitable positioning of the stop element 4 can be stored and called up in the control unit 6 for each successive insertion of a weft thread.

The position of the attachment element 4 specified by the control unit 6 can also be specified as a function of weaving parameters of the weaving machine, for example whether weaving is carried out at normal speed or slow speed, whether a weft thread is inserted directly after the machine starts or the like. In normal weaving, the stop element 4 is positioned closer to the shed than in the case of slow weaving, since the higher the speed, the closer the stop element 4 should be to the shed. If the weaving machine has not yet reached the operating speed when the machine starts up, the stop element is ment _{4 positioned} slightly further away from the shed than with normal weaving.

_{As shown} in FIG. ₁ 0, the stop element 4 can also be moved in the direction of arrow P (against the direction of arrow Q) in order to move the stop surface 22 out of the region of the movement path 24 of the stop part 23 of the gripper clamp 2 . The decision whether the on ^¬ impact element 4 tion in the position of FIG. 7 or in the Posi¬ of Fig. 10 is moved is dependent on the position in which the stop element 4 previously found (Fig. 5), ie of the path that the stop element 4 has to travel in order to bring the stop surface 22 out of the movement path 24 of the stop part 23 of the gripper clamp 2. The aim is to keep this path as short as possible in order to save time. Of course, the stop element 4 can also be moved out of its position according to FIG. 5 when the slave gripper 3 moves out of the shed in the direction P and the stop part 23 is still in contact with the stop surface 22 of the stop element 4 is located. The stop element 4 can thus be brought out of the movement path 24 of the stop part 23 of the gripper clamp 2 of the slave gripper 3 in good time before the slave gripper 3 then moves past the stop element 4 in the direction Q.

In the embodiment according to FIG. 11, guide bolts 29 are attached to the stop element 4 and are guided in slots 30 of the holder 7. These slots 30 have a rectilinear central section which runs at least approximately parallel to the running direction A of the slave gripper 3. This middle section is adjoined by end sections which, in this exemplary embodiment, extend obliquely outward from the movement path 4 of the stop part 23 of the gripper clamp 2. This results in the same function as in the embodiment according to FIGS. 1 to 4. lo

12 and 13 show an embodiment of a device according to the invention, in which the drive motor is a linear motor. The housing 31 of the linear motor is pivotally attached to an attachment of the holder 7. The armature 32, which can be extended from the housing 31 or moved into the housing 31, is fastened to a pivot point 17 of the stop element 4. In this exemplary embodiment, the guide elements consist of guide bolts 18 which are fastened to the holder 7 and which cooperate with slots 33 in the stop element 4. In this embodiment, the slots 33 have only one inclined end section adjoining the straight-line part. This device is used, for example, to close a donor gripper 34 which picks up a weft thread 28 and transports it to the middle of a shed. The encoder rapier 34 contains a rapier clamp 36 which holds the weft thread 28 clamped on a stationary clamping piece 37. The gripper clamp 36 has a stop part 35, to which the stop surface 22 of the stop element 4 is assigned. The stop element 4 cooperates with the stop part 35 of the hook clamp 36 of the picker 34 when the picker 34 is moved into the shed 28 with the weft thread 28 in the direction of arrow P in the direction of the arrow P. The stop element 4, on the other hand, does not work together with the sensor gripper 34, i.e. with the stop part 35 when the donor gripper 34 moves out of the shed in the direction of arrow Q in accordance with FIG. 13. The stop element 4 is moved into a position in which the guide bolts 18 are located in the oblique end section of the slots 33. In this position, the stop element 4 with its stop surface 22 is moved out of the movement path 34 of the stop part 35 of the gripper clamp 36, which is held in the clamped position by means of a spring 38.

In the case of a donor gripper 34, the position in which the weft thread is clamped by the donor gripper 34 is essential. The position of the stop element 4 is determined by means of the linear motor 31, 32 controlled by the control unit 6 so that the stop part 35 of the gripper clamp 36 of the encoder gripper 34 is released from the stop element 4 at the correct time when the encoder gripper 34 moves in the direction of arrow P, so that the weft thread 28 is clamped. These polyvinyl sition of the stop element is a function of the _G È¬ speed of the loom, the thickness or elasticity of the weft yarn 28, or the type of the weft yarn 28 heran¬ leading feed means set in a similar manner as with respect to the gripper rapier 3 has been explained with reference to FIGS. 5 to 9.

In an embodiment that is not shown, both the guide bolts and the slots are each provided on a movable component, which are adjusted via a drive motor which is fixedly mounted on a holder. For example, slots corresponding to the slots _{21 of} the stop element 4 as shown in FIG. 1 can be provided in a first element, while guide bolts corresponding to the guide bolts 29 of the stop element 4 as shown in FIG. 11 are provided in another component are. The stop element is attached to one of the components mentioned or is formed by one of the components.

FIG. 14 shows an embodiment of a device according to the invention, which is modified with respect to FIG. 1 with respect to the slots 39 of the stop element 4. The slots 39 have a central section 40 which is oriented at least approximately parallel to the direction of travel of the slave gripper 3. This central section is followed by oblique sections 41, to which sections 42 are connected, which again run essentially parallel to the running direction of the slave gripper 3. If the guide bolts 18 are at the height of one of the end sections ₄ 2, the stop element 4 with its stop surface 22 is outside the movement path 24 of the stop part 2 ₃ Gripper clamp 2. The position of the guide pins 18 in the end sections 42 is then less important.

The embodiment according to FIG. 15 also essentially corresponds to the embodiment according to FIGS. 1 to 4, the slots 43 of the stop element 4 likewise having a modified shape. These slots 43 have two parallel end sections 45, 47 and between them a section which consists of two parts 44, 46 which run obliquely to the running direction of the slave gripper 3. In this embodiment, the stop element 4 with its stop surface 22 is outside the movement path 24 of the stop part 23 of the gripper clamp 2 when the guide bolts are located in the central, approximately V-shaped section 44, 46.

In order to bring the stop element 4 out of the movement path 24 of the stop part 23 of the gripper clamp 2 of the gripper 3 or out of the movement path 24 of the stop part 35 of the gripper clamp 36 of the master gripper 34, the stop element 4 need not necessarily be brought into a position in which the guide bolts 18 or 29 abut one end of the slots 21, 30 or 33. If a stepping motor is used as the drive motor 5 or 31, this has the advantage that the path of the stop element can be limited in such a way that the guide bolts 18, 29 are always at a distance from the ends of the slots 21, 30 , 33, 39, 43 are located. The guide bolts 18, 29 then do not strike the ends of the slots 21, 30, 33, 39, 43, which increases the service life. The guide bolts 18 or 29 can only be brought into contact with one end of the slots 21, 30, 33, 39, 43 for a known adjustment of the stepping motor. The stepper motor thus reaches a known reference position. This adjustment can take place, for example, immediately before the weaving machine starts.

The adjustable mounting of the bracket 7 on the frame 9 can be done in other ways than by means of the eccentric 10 and O 97/40218 FCTΪEP97 / 01917

'3

Screws 12 take place. In an embodiment not shown, fastening elements according to US Pat. No. 5,092,371 are used to enable an adjustable fastening.

In the embodiment according to FIG. 16, which corresponds in its basic structure to the embodiment according to the device 1 according to FIGS. 1 to 4, 4 switching means 60 are provided in the area of the stop element, which are for example attached to the holder 7. By means of this switching means 60, the drive motor 5 can be switched on and off by the operator in such a way that it moves the stop element 4 to the right or left by predetermined paths. The switching means 60, which is connected to the control device 6, contains a switch 61, for example a pressure switch, which switches the device 1 to manual operation in the one position and switches the device to the one switched by the control unit 6 in the other position, switches running operation according to a predetermined program.

16 also contains a switch 62, for example a pressure switch, which supplies a signal to the control unit 6, due to which the drive motor 5 is moved to the right. Furthermore, a switch 63 is provided, for example also a pressure switch, which, when actuated, supplies a signal to the control unit 6 so that the drive is moved to the left.

By operating switches 61, 62 and 63, the operator can first check the function of the device. In addition, by actuating the switches 62, 63, the stop element can be moved into a reference position, in particular into the right or left end position, by means of which a stepping motor serving as the drive motor 5 is adjusted before the weaving machine is started. In addition, the operator can use the switching means 60 a correction of a position of the stop element 4 predetermined by the control unit 6 according to a program. It can visually check whether the weft thread in question protrudes with the correct length over the selvedge. If this is not the case, it can switch to manual operation by means of the switch 61 and correct the position of the stop element 4 by actuating the switches 62 or 63. This corrected position is then adopted by the control unit 6 for the weft thread in question as soon as the switch 61 switches back to automatic operation.

Other embodiments are also possible for the switching means 60. For example, only one switch 62 can be provided, e.g. a pressure switch which, when actuated, controls the drive motor 5 via the control unit 6 so that the stop element 4 is moved to an end position. The next actuation of this switch 62 then causes the stop element 4 to be moved in the opposite direction by means of the drive motor 5 into the opposite end position.

The structure of the device according to FIG. 17 corresponds to the embodiment according to FIGS. 1 to 4. In addition, a switching means 60 'is provided which is arranged in the area of the holder 7. However, it is also possible to integrate the switching means 60 'into an input keyboard which is provided for the control unit 6.

In the embodiment according to FIG. 17, the switching means 60 'contains an adjusting element 64, for example a potentiometer, which, when turned to the right or left, supplies a signal to the control unit, so that the drive motor 5 correspondingly rotates to the right or left and the stop element 4 ent ¬ adjusted accordingly. ZI

In the embodiment according to FIG. 17, the switching means 60 'contains a switch 65, by means of which and with the aid of the adjusting element 64, the program stored in the control unit 6 can be modified or adapted. If, for example, the operator determines that the ends of the inserted weft threads protrude too far beyond the selvedge, the position of the stop element can be corrected with the aid of the adjusting element, for example by turning the adjusting element 64 to the left. By actuating switch 65, this corrected value is transferred to control unit 6. If the ends of the weft protrude too little beyond the selvedge, an opposite correction is made, i.e. the adjusting element 64 is rotated accordingly, for example to the right. The new value is then entered into the control unit 6 by actuating the switch 65. This possibility of correction is of course so limited that the drive motor 5 does not attempt to move the stop element 4 into a position in which the guide bolts 18 have to be moved beyond the ends of the slots 21. With a stepper motor as the drive motor 5, this means that the corrected values can never be less than zero and never greater than a set maximum value. This possibility of correction is advantageous since the positions stored in the control unit 6 are predetermined in advance before the device 1 with its holder 7 is mounted on the frame 9. In practice, this assembly cannot be carried out in a very exact position and thus in a very exact orientation in the running direction A of the slave gripper 3.

According to an embodiment not shown, a switch 65 is provided for each weft thread to be entered, by means of which actuation a position corrected with the aid of the adjusting element 64 can be entered into the control unit 6 for each weft thread. In one embodiment, which is not shown, sensors are attached in the area of the selvedge, which detect the length with which the inserted weft threads protrude beyond the selvedge. The sensors transmit corresponding signals to the control unit 6, which contains an evaluation device to measure the ge ¬ correct positions of the stop element 4 according to the measured length. If the measured length with which the weft threads protrude beyond the selvedge is greater than a set value, the position of the stop element 4 is changed so that the stop part 23 of the gripper clamp 2 of the slave gripper 3 earlier with the stop surface 22 of the Stop element comes into contact, while when the measured length is less than the predetermined value, the position of the stop element 4 is adjusted so that the stop part 23 of the gripper clamp 2 of the slave gripper 3 starts earlier .

16 and 17, the switching means 60, 60 'have only been explained using the example of a slave gripper, it goes without saying that corresponding switching means can also be provided for a sensor gripper. It is also possible to use switching means 60, 60 'of this type also in all the other embodiments described above.

The gripper clamps 2, 36 and their stop parts 23, 35 are only shown schematically in all the exemplary embodiments explained. Of course, the gripper clamps do not have to be in one piece with the stop parts. The stop parts can be connected to the gripper clamp by means of one or more transmission elements.

The invention is not limited to the exemplary embodiments described above and explained with the aid of the drawings, which can be changed within the scope of the specialist knowledge of a person skilled in the art. The scope of protection is determined exclusively by the claims.

Claims

claims

1. Device (1) for opening a gripper clamp (2, 36) of a gripper (3, 34) of a weaving machine with a stop element (4) which, in the movement path (24), of a stop part assigned to the gripper clamp (2, 36) (23, 35) is arranged and its position in the running direction (A) of the gripper is adjustable by means of a drive (5; 31, 32) controlled by a control unit (6), characterized in that the stop element (4) is guided in a guide such that it can be moved out of the movement path (24) of the stop part (23, 35) on command from the control unit (6).

2. Device according to claim 1, characterized in that the stop element (4) is adjustable in a guide, the at least one in the running direction (A) of the gripper (3, 34) extending guide section and at least one inclined to the stop element ( 4) from the movement path (24) of the stop part (23, 35) of the gripper clamp

(2, 36) has moving out guide section.

3. Apparatus according to claim 1 or 2, characterized gekenn¬ characterized in that the drive (5; 31, 32) is connected by means of transmission means to the stop element (4), which allow a linear adjustment movement and an oblique Verstellbewe¬ movement.

4. Device according to one of claims 1 to 3, characterized in that as a drive for the stop element (4) from the control unit (6) controlled, electrical positioning drive (5; 31, 32) is provided.

5. The device according to claim 4, characterized in that in the control unit (6) by means of the positioning drive (5; 31, 32) approachable positions for the stop element (4) are stored, the properties of to be processed Weft threads and / or the formation of a shed and / or operating states of the weaving machine and / or operating parameters are assigned.

6. Device according to one of claims 1 to 5, characterized in that the stop element (4) and the associated drive (5; 31, 32) are arranged on a machine frame (9) of the weaving machine by means of a common holder (7) .

7. The device according to claim 6, characterized in that the holder (7) by means of an adjustment in the running direction (A) of the gripper (3, 34) and / or transverse to this running direction (A) allowing fastening elements (10, 12) on the Machine frame (9) is attached.

8. The device according to claim 6 or 7, characterized gekenn¬ characterized in that the stop element (4) by means of the positioning drive (5; 31, 32) relative to the bracket (7) is adjustable, wherein between the bracket and the Stop element guide elements are provided which define at least one rectilinear guide section and at least one guide section running obliquely thereto.

9. The device according to claim 8, characterized in that the guide elements are designed as guide slots (21, 30, 33, 39, 43) and guide pins (18, 29) guided therein.

10. Device according to one of claims 1 to 9, characterized in that the adjustment path of the positioning drive (5; 31, 32) is limited to a length which is shorter than the length of the slots (21, 30, 33, 39, 43) is.

11. Device according to one of claims 1 to 10, characterized in that preferably in the area of the arrival 2S

impact element (4) switching means (60, 60 ') for manually actuating the positioning drive (5; 31, 32) are arranged.

12. The apparatus according to claim 11, characterized in that preferably in the area of the stop element (4) input means (60, 60 ') for entering positions to be reached of the stop element (4) in the control unit (6) and / or for correcting predetermined positions of the control unit (6) are provided.