FR2690466A1 - Device for the presentation of the weft yarn to the pliers of pliers weaving machines. - Google Patents

Abstract

Device for presenting the weft thread to the grippers of gripper weaving machines in which, for guiding the weft thread to be inserted into the shed (18), a fixed guide fork (7) with a guide groove is provided (9), the latter is arranged in the plane of the shed (18), widens in the direction of the path of the clamps (16, 16 ') and is open and extends in the plane of the clamp at least up to the plane of the threshing zone (13) of the weft thread then, in this guide groove (9), between the threshing zone (13) of the weft thread and the path of the grippers (16, 16 ') , is provided, for the weft thread, a switchable stopper in an inactive position.

Description

The invention relates to a device for the presentation of the weft yarn.

  to the pliers of the pliers weaving machines in the crowd entrance area comprising a thread clamp on the leaf in the plane of the weaving comb, a thread guide on the face of the pliers' trajectory, this face being diverted from the weaving comb, a thread guiding element near the thread clamp for the introduction of the weft thread into the thread clamp and a separating device for the separation of the weft thread inserted near the edge of the fabric and near the path of movement of the wire clamp. A device of the type described in the introduction is, inter alia, known from EP 273 350 The device, which is shown there, has, at the entrance of the crowd on the leaf, near the lateral delimitation of the weaving comb, each time, a cutter and a neighboring wire clamp directly outside Outside the movement zone of the wire clamp, there is provided a wire guide which can, in addition to this here, slide relatively in the

leaf movement plan.

  This thread guide, which can take various positions during the insertion of the weft, is used, first, to hold the weft thread, to be inserted, away from the warp threads

forming the frame.

  At the same time, the purpose of this thread guide is to facilitate the introduction of the weft thread into the leaf clamp of the leaf after the successful threshing of the weft thread After the threshing of the weft thread, the weft thread inserted last is cut by the cutter on the leaf The end of the wire

  now free weft remains in the leaf clamp.

  The thread guide located in the immediate vicinity of the thread clamp moves together with the thread clamp and the leaf behind the path of the clamps which are provided for the insertion of the weft Another thread guide, which is located in front of the gripper path, ensures that the weft thread crosses the gripper path on a defined line and can be gripped by the gripper wire clamp at this point. With this device it is possible to insert weft threads in an uninterrupted order If you want with this device, as is necessary for example on weaving machines with double weft for a three-turn tying, do not insert a weft, then we need expensive drive means, controlled by program for the opening and closing of the wire clamp and for the actuation of the cutter Such means must be provided

  in another form for each divergent frame order.

  On weaving machines of hitherto known embodiments, it is necessary, in the event of a thread break or any other error on the machine, to stop the weaving machine very quickly, given the large quantity of moving parts of the machine. weaving, this can only be done in a relatively long period of time In this period, at least one weft is inserted which, in the event of a break inside the crowd, must be removed from the fabric This is done by the causes the machine to be turned in reverse, the weft thread is released again by the warp threads and can be removed These work steps require a significant labor expense

  manual and extends machine downtime.

  The object of the invention is to remedy the cited defects.

  The object of the invention consists in proposing a device with which it is possible to configure the interruption of the insertion of the frame as a function of a program or as a function of a selected stop signal from the machine The deployment of the means of

  mechanical adjustment should be limited to a minimum.

  According to the invention, this object is achieved in the fact that for guiding the weft thread to be inserted into the shed, there is provided a fixed guide fork with a guide groove, that the guide groove is disposed in the plane of the crowd, that the guide groove widens in the direction of the gripper path and is open and that the guide groove extends in the plane of the wire clamp at least as far as the plane of the threshing zone of the weft thread and that in the guide groove between the threshing area of the weft thread and the path of the clamps, there is provided for the thread

  frame, a switchable stopper in an inactive position.

  On the one hand, the guide groove is intended to guide the

  weft to insert from the crowd warp threads.

  Simultaneously, the guide groove is suitable, in its narrow zone, for guiding the weft thread in the plane of the thread clamp. The stopper introduced in the plane of the guide groove ensures, in its active position, an introduction certain weft in the action area

  wire clamp and cutting device.

  Therefore, the stroke of the leaf is exploited for the insertion movement. It does not matter here if the wire clamp is provided with a simple elastic mobile clamping element or with a driven clamping lever. the insertion of a weft by expelling the stopper from the area of the guide groove The weft thread, set in motion by the leaf in the threshing area of the weft thread, is no longer retained by the stopper and thus no longer reaches the area of the cutter and the wire clamp of the leaf

  weft thread remains connected to the edge of the fabric.

  During the return stroke,

  presented no weft thread to the clamp actuated as a result.

  Thus, it cannot insert any weft thread into the newly formed crowd. In this way, it is possible with simple means to avoid the insertion of a single weft or

  a few frames one behind the other.

  The insertion of a weft is avoided by means of the stopper control by a sample program or by a selected stop pulse of the weaving machine The art and the way of rendering the stopper ineffective for the weft thread are defined by the fact that the stopper is switchable outside the region of the guide groove transversely to the guide groove, that the stopper is switchable in the longitudinal direction of the guide groove as far as the weft beating zone , that the stopper can pivot transversely to the guide groove and that it is associated with a sliding surface which is at a distance close to the plane of the wire clamp, that the stopper is switchable by means of an electromagnet, that the stopper can be controlled in dependence with a weft insertion program, and that the stopper is switchable by a pulse generator of the stop command of the weaving machine. The simplest switching possibility consists in the made of exit

  transversely the stopper out of the guide groove.

  For setting the stopper along the threshing movement of the leaf, it is necessary to remove the stopper enough so that the weft thread no longer reaches the area of the thread clamp and the cutter. This variant is, first of all , used when the thread guide in front of the gripper path is not fixed to the leaf It is also possible to lift the weft thread, using the lane change, above the stopper and guide it as well

  outside the area of action of the wire clamp and the cutter.

  Expensive mechanical transfer members are thus avoided when the stopper or the lane change is directly reversible by means of an electromagnet. The magnet can thus be controlled by an electric pulse of a program command for the order d insertion of the frame or

  by an electrical stop pulse for the machine.

  Besides an economical realization for the weft control of an article by double weft, woven for example with three turns, this device has the advantage that, in a negligible short period of time, after an impulse for immobilization of the machine, the insertion of the weft can

 be interrupted.

  So when the machine slows down, no weft thread is inserted into the crowd. The tedious removal of broken weft threads from the fabric is thus almost

completely eliminated.

  Various other features of the invention

  moreover emerge from the detailed description which follows.

  Embodiments of the subject of the invention are shown, by way of nonlimiting examples, in

attached drawings.

  Fig 1 is a schematic top view of the crowd entry area in a position in which the insertion of the frame has just been completed by the

pliers.

  FIG. 2 is a view corresponding to FIG. 1 according to which the leaf has reached the weft wire threshing position and the weft wire is prepared for a new

weft insertion.

  Fig 3 is a view similar to Fig 1 before the start of a weft insertion in the presentation phase

of a weft thread.

  Fig 4 is a view corresponding to Fig 2, o the stopper for the weft thread is not in the working position

  and o the wire clamp and the cutting device are inactive.

  FIG. 5 is a view corresponding to FIG. 4, where the uncut weft thread is not presented to the clamp in

view of recovery.

  Fig 6 is a side view of a guide fork for a double shed weaving machine with the switchable stop transverse to the slot groove with, in the background, a double sheaf shown schematically. Fig 7 is an enlarged representation of the stopper

  in the area of the guide groove in detail A in fig 6.

  Fig 8 is a schematic representation of a guide groove with a retractable stopper in the direction of

  weft threshing for the weft yarn.

  Fig 9 is another variant of the configuration of the switchable stopper in the form of a lane change. The weaving machine, according to the embodiment, is equipped, in a manner known per se, with a leaf 6 which carries, in the weaving zone, the weaving comb 5 The weaving comb 5 is moved by the leaf 6 enters a rear position during the insertion of the frame and a

  position before during weft threshing.

  The leaf 6 pauses in its rear position.

  During this break, the claws 16, 16 ′ of the clamp move towards the middle of the weaving machine and vice versa with a view to inserting the weft. On the leaf is stably arranged a cutting and clamping 1 The cutting device consists of a fixed blade 4, a movable blade 3 near the outer edge of the weaving comb 5 Outside, near the cutting device 3, 4, is a clamp wire 2, the clamping plane of which is oriented towards the cutting plane of the blades 3, 4 This wire clamp 2 is also stably fixed to the leaf 6 On a part extended towards the outside of the leaf 6 is fixed a guide wire 15 which, seen in the direction of threshing, is arranged in front of the movement path of the grippers 16 This wire guide 15 is, as a rule, designed as a closed eyelet Between the wire guide 15 and the movement path of the greenhouse -wire 2, is fixedly arranged a guide fork 7 with teeth 8 parallel to the trajectory of

moving the wire clamp 2.

  The guide fork 7 is equipped with guide grooves 9, limited by the teeth 8 for the weft threads 14 of the upper crowd and the lower crowd These guide grooves 9 are widened in the direction of the movement path of the grippers 16 , 16 'and receive, without

  problem, at this point the weft thread presented 14.

  In the direction of the beating area of the weft thread 13, 13 ', the guide grooves 9 tighten and form a practically dog-like guide for each of the weft threads 14 This narrow area of the guide groove 9 is close

  immediate action plan for wire clamp 2 and blades 3,4.

  A reversible stopper 10 for the weft thread 14 is provided at a distance from the threshing area of the weft thread.

guide groove 9.

  In FIG. 6, this stopper 10 constitutes the front end of a bolt 11, which is axially movable by means of an electromagnet 12, which is designed, functionally, as a magnet with a swinging frame Si this stopper 10 is in the plane of the guide groove 9, the weft thread 14 is retained before reaching the threshing area 13 of the weft thread and therefore arrives in the thread clamp 2 and in the zone of action of the blades 3, 4 which, with the weaving comb 5, approach the threshing zone 13 of the weft thread After the successful weft threshing, the cutting device and its blades 3, 4 are activated The wire clamp 2 remains closed and takes up the end of the weft thread which has become free in the rear position of the leaf 6 At this point, the weft thread 14 is then replaced crosswise above the path of the clamps 16, 16 'The clamp of the clamp 16, 16' can grip the weft 14 and

  insert it, in a known manner, into the open crowd 18, 18 ′.

  The weaving process thus continues normally.

  If for reasons of weaving technique or for reasons of stopping the machine, no weft thread 14 is inserted, the electromagnet 12 is reversed so as to raise the bolt 11 with its front end, the buffer 10,

outside the plane of the guide groove 9.

  During the next weft threshing, the weft thread 14 stretched between the weaving comb 5 and the thread guide 15 is brought unhindered into the threshing zone 13 of the weft thread. Thus, this weft thread 14 does not reach or in the area of the thread clamp 2, nor in the area of the blades 3, 4 This weft thread 14 remains connected to the edge 17 of the fabric By the common movement of the thread guide 15 and of the leaf 6, the end of the thread leading to the edge 17 of the fabric is brought behind the stopper 10 in the

guide groove 9.

  In this way, during the next threshing stroke of the leaf 6, that is to say when the stopper 10 is reactivated, the weft thread 14 is brought into the area of the thread clamp 2 and of the blades 3, 4 The weft thread 14 is cut and the free end of the weft thread is retained by the thread clamp 2, above

  the movement trajectory of the clamps 16, 16 '.

  Weft insertion can thus be interrupted over a period of time as long as desired, this period

  being indicated by the magnet control 12 The reintro-

  duction of the weft thread 14 in the weaving operation

  simply requires activation of the stopper 10 via the

magnet 12.

  With a view to better guiding the weft thread 14 in the area between the edge 17 of the fabric and the guide fork 7, an additional guide fork is provided, functionally, between the edge 17 of the fabric and the blades 3 , 4 This guide fork does not, however, have any switchable stopper 10 But it is housed, like the

  guide fork 7, fixedly on the machine frame.

  The cutting device 3, 4 must not be absolutely fixed on the leaf 6 It is also possible, to house it fixedly on the frame, in the threshing zone 13 of the weft thread and to drive it However, it is important that the weft thread 14 which is not blocked by the

  buffer 10, has a free space, where it is not cut.

  The wire clamp 2, on the other hand, should always be placed on the leaf 6, because it must move with it behind the movement path of the clamps 16, to present the

thread when inserting the weft.

  If the wire guide 15 is not fixed on the leaf 6, it is appropriate, as shown in FIG. 8, to place the switchable stopper 10 ′, not transversely to the guide groove 9, but to remove it in the plane of this guide groove 9 up to behind the threshing area 13 of the weft thread In this way, additional elements for bringing the weft thread 14 back into the area in front of the stopper 10

become superfluous.

  The variant shown in FIG. 9 shows how a pivoting stopper 10 "engages the guide of the weft thread in a position where the weft thread 14 is not grasped by the

wire clamp 2 and blades 3, 4.

  Other embodiments of the switchable stopper are entirely conceivable in the application of

the known technique.

Claims (9)

  1 Device for the presentation of the weft yarn to the pliers of pliers weaving machines in the area of the crowd entrance comprising a thread clamp on the leaf in the plane of the weaving comb, a thread guide on the face from the path of the pliers, this face being turned away from the weaving comb, a thread guiding element near the thread clamp for the introduction of the weft thread into the thread clamp and a separating device for the separation of the thread weft inserted near the edge of the fabric and near the path of movement of the thread clamp, characterized in that for guiding the weft thread (14) to be inserted into the shed (18), a fixed fork is provided. guide (7) with a guide groove (9), the guide groove (9) is arranged in the plane of the shed (18), widens in the direction of the path of the clamps (16,  16 ') and is open and extends in the plane of the thread clamp (2) at least as far as the plane of the beating zone (13) of the weft thread, and in the guide groove (9) between the threshing area (13) of the weft thread and the path of the clamps (16, 16 '), a switchable stopper is provided for the weft thread (14) (10) in an inactive position.   2 Device according to claim 1, characterized in that the stopper (10) is switchable outside the area of   the guide groove (9) transversely to the guide groove (9).   3 Device according to claim 1, characterized in that the stopper (10) is switchable in the longitudinal direction of the guide groove (9) up to the area of threshing of the weft thread (13).   4 Device according to claim 1, characterized in that the stopper (10) can pivot transversely to the guide groove and that it is associated with a sliding surface (9 ') which is at a distance close to the plane of the wire clamp (2).   5 Device according to claim 1 to 4, characterized in that the stopper (10) is switchable by means an electromagnet (12).   6 Device according to claim 1 to 5, characterized in that the stopper (10) can be controlled by   dependence with a frame insertion program.   7 Device according to claim 1 to 6, characterized in that the stopper is switchable by a pulse generator of the machine stop command to weave.   8 Device according to claim 1 to 7 for weaving machines for double carpets having at least two crowds arranged one above the other, characterized in that the guide fork (7) has, for each crowd ( 18, 18 '), a guide groove (9) and at each guide groove   (9) is associated with a stopper (10) with independent control.