JP3221882U - Cutting device for weft yarn of gripper loom without forming false ears - Google Patents

Abstract

An object of the present invention is to provide a weft cutting device capable of cutting all weft ends very accurately and evenly regardless of the elasticity of the weft. A weft cutting device for a projectile loom having a holding function of a weft yarn for a gripper loom or in flight, the loom having a sley and a weir R integrated with the loom, the sley and the weir being A weft of the type in which the weft is cut after insertion into the shed, and the weft cutting device comprises a plurality of clamping grippers P for each weft in waiting, and a cutting member H with a weft cutting point . The cutting member is placed in a fixed position independently of the position of the clamping gripper, and the associated cutting point is approximately aligned with the battling line B of the crease to be formed. Furthermore, during the stamping process, weft thread guiding means 1 are provided on the opposite side to the cutting surface of the cutting member, integrally adjacent to the hook during movement. [Selected figure] Figure 1

Description

  The present invention relates to a cutting device for weft yarns in a gripper loom, which does not form false ears on the supply side of the loom. The weft cutting device according to the invention can furthermore be used in a type of projectile weaving machine in which the projectile has the function of clamping and releasing the weft in flight as well as the gripper. A weaving machine of this kind is disclosed, for example, in EP-A 34 15 671 A1 filed under the same applicant's name.

  As known to the person skilled in the art, the term "fake ears" refers to warp groups added on both sides of the warp intended for fabric formation, at a certain distance therefrom. The additional warp groups are often interwoven with the weft in a simple plain weave or in any other manner that may differ from the method of producing the fabric.

  The first purpose of the false ear is that the fabric is properly formed by equally cutting the fully-stretched weft between the fabric and the spaced false ear warp by a cutting device. As soon as the false ear is cut away from the fabric, an area several centimeters downstream of the batting line is formed. As a result, the edge of the fabric, in particular the peripheral edge formed by the weft threads protruding from the fabric (hereinafter simply referred to as "weft end") becomes completely even. Next, another purpose of the false ear is to individually and preferably in the insertion step done via the shed closure so as to fix while fully stretching the ends of the weft to prevent defects in the weft of the fabric. It is to bind the weft yarn before the closure of the shed of the warp yarn. As will be described in more detail below, yet another purpose of the false ear is to be the connection point of the waiting weft yarn. Another object of the false ear is that the physical characteristics of the fabric warp and different physical characteristics, ie more suitable to provide a strong and stable connection of the weft and a stable connection with the waiting weft. To enable use with warp yarns.

  As used herein, the "feed side of the loom" is the side into which the weft is inserted and is almost always to the left of the loom relative to the standard operating position taken by the weaver.

  In a gripper loom, false ears are used, in particular, on the supply side of the loom to maintain the physical connection between the weft waiting for weaving and the respective supply device so that they can be tightened by the carrier gripper Be done. When insertion into the shed is complete, the weft yarns are not cut and extend along the edge of the fabric at one end and are connected to the fabric while being held in place by specific guide hooks, and at the other end It is connected to the respective weft supply device through the lever of the weft selection device. Weft cutting is performed after the waiting weft is again selected and the weft drawn between the weft selection device and the fabric edge is clamped by the carrier gripper and before it is pulled into the shed by the carrier gripper. Be done.

  This widely used weaving method is obviously associated with the warp forming the false ear and the weft part woven into the false ear, and if it extends and is somewhat stretched adjacent to the fabric until the next insertion Depending on the design of the fabric and the frequency of recurrence of a particular weft, for certain weft yarn sections, there is a significant waste of material.

  The purpose of weaving without false ears has already been addressed several times in the industry through various technical solutions and associated performances, in the name of the same applicant in EP 3425094 A1, textiles and machines The solution is disclosed as being particularly satisfactory from both of the two perspectives. According to this solution, in fact, all waiting weft yarns are stably held adjacent to the fabric being formed by their respective clamping grippers. After the weft yarn is taken out of its own clamping gripper and inserted into the shed, in the next wefting operation on the woven fabric by the weir, the weft yarn is pulled back, and in the same clamping gripper as it was taken out It is tightened until just before cutting. In this way, it is possible to cut the weft evenly while avoiding false ears completely, whereby it is possible to weave a fabric with weft edges having a constant height.

  The cutting device used to cut the weft yarn is a device of great importance in all known weaving systems which do not form false ears. Such a device can in fact only operate after the weft thread, which has already been inserted in the shed and struck by the weir, is tightened again on its own clamping gripper. In a device of known type, in particular the device described in the aforementioned patent, the weft yarn is moved into position by the movement of the weir. Thus, in order to ensure good cutting uniformity, weft cutting has to be carried out immediately after the weft has been tightened with its own clamping gripper. As the weir advances, the weft yarns, one end of which is constrained to their own clamping gripper, may progressively tilt relative to the batting line, resulting in an incorrect cutting action. Therefore, it is ultimately necessary to perform the weft cutting operation while the bale is still moving, i.e. shortly before the final battering position on the formed fabric.

  However, in this initial position, the weft yarn is often not yet completely fixed in place by the shed closure and then, as a result of the cutting operation, the weft yarn shrinks slightly and partially into the fabric and In the case of elastic wefts, this occurs to a much greater extent. Thus, in order to avoid this type of problem, weft end lengths of at least 6 to 7 mm have been required so far to be able to balance against partial shrinkage of the weft into fabric. Such partial contraction may result from the cutting operation being performed when the weft yarn is not yet completely fixed between the warps, i.e. when the shed closing phase is not completely finished.

  Therefore, the problem to be solved by the present invention in the background of such prior art is a gripper loom and the like as well because it cuts all weft ends very accurately and evenly, regardless of the elasticity of wefts used from time to time. It is an object of the present invention to provide a weft cutting device for a working projectile loom.

  The first object of the present invention is that the welting operation can be carried out when the stamping and traversing operations have already been substantially completed, and as far as the elastic partial contraction of the weft onto the fabric is concerned, a sufficiently fixed weft. It is an object of the present invention to provide a weft cutting device which enables the cutting of weft yarns which enables the above.

  A second object of the present invention is to provide a weft cutting device of the kind set forth which is additionally provided with guiding means for keeping the weft completely perpendicular to the cutting blade working surface during the movement of the weir. It is.

  Another object of the present invention is for weft yarns as described above further provided with holding means for fully stretching the weft yarns before and after cutting, regardless of the weft and warp position when the cutting operation is performed It is providing a cutting device.

  By means of a weft cutting device having the features defined in claim 1, this task is solved and these objects are achieved. Other preferred features of the above device are defined in the dependent claims.

Further features and advantages of the weft cutting device according to the invention will in any case be more apparent from the following detailed description of a preferred embodiment, given merely by way of non-limiting example and shown in the attached drawings. I will.
FIG. 1 is a perspective view of a first embodiment of the weft cutting device according to the present invention. It is a perspective view of 2nd Embodiment of the cutting device of weft of this invention. It is a front view of the cutting device of FIG. It is a front view of the cutting device of FIG.

  According to the invention, in order to solve the problems highlighted above by means of a very effective solution, we first cut the weft yarn with the known system into uneven weft yarn length or yarn into the fabric. As a result of analyzing the reasons that frequently cause serious problems such as variable shrinkage, these drawbacks are due to returning the inserted weft to its own clamping gripper, bringing the weft into contact with the cutting member, equal cutting. It was hypothesized that all stretching the weft yarn to the required extent could be attributed to relying only on the weft of the loom.

  This plurality of functions assigned to the weft of the weaving machine greatly reduces the time frame for achieving weft cutting under optimal conditions. Furthermore, this time frame often corresponds to a loom cycle stage in which the weft is not sufficiently fixed by the crossing of the warps resulting from the closure of the shed. Therefore, the above-mentioned defect that the weft end length becomes uneven can easily occur.

  The present invention was conceived based on the analysis of the major problems with the operation and adjustment of known cutting devices by developing the improved cutting device of the present invention. In this cutting device, means for controlling the precise position of the weft are provided, thereby supplementing the function of the weir so that the time frame in which weft cutting can be achieved under optimum conditions can be maintained more widely. It is possible to ensure equal weft cutting. Thanks to the construction of this weft cutter, it is possible at the same time to achieve very good uniformity of the weft end edge and at the same time further reduce the weft end length to an optimum size of 3 to 4 mm.

  Some preferred embodiments of the weft cutting device according to the invention are shown in the attached drawing for a weft handling device as disclosed in EP-3425094A1. However, the cutting device according to the invention is held in place by the other weft handling devices which do not form false ears, ie the waiting weft threads are held in position by their respective clamping grippers which have pulled them out until they are inserted into the shed. It is also applicable to a weft handling device in which the weft yarn which has just been inserted into the shed is subsequently retightened to the clamping gripper during the execution of the beating operation by the weir.

  The drawing schematically shows the essential parts of the weft handling device described above, which comprises a fan-shaped weft switching plate S rotating about a rotation axis C, and the number of weft threads to be processed on the weft switching plate. The same number of clamping grippers P are mounted. The weft switching plate S is arranged on the side of the weaving machine, in which only the weir R, the battling line B and the outer end of the textile breast beam T are shown. Such weft handling devices as well as the features and operating modes of such known devices of the prior art are broadly disclosed in EP-34 250 94 A1 and reference should be made to a better understanding of these devices.

  In any case, the construction of the cutting device according to the invention is not determined by the particular weft handling device involved, the only requirement being that the weft handling device does not provide for the use of false ears and waits in the weft insertion area In order to hold in place the free end of each weft thread, it is to provide individual clamping grippers or similar elements.

  The cutting device according to the invention initially comprises a weft cutting member in a manner known per se. Preferably, the cutting member comprises a circular cutting blade H which rotates at a constant speed. However, it is also possible to use a conventional scissors-type cutting member which performs the cutting operation with two mutually moving linear blades. In any case, the cutting member H is fixed to the edge of the loom regardless of the position of the clamping gripper. Specifically, when the cutting member H is arranged such that the cutting point is substantially aligned with the batting line B of the ridge R with respect to the fabric to be formed, when the batting operation of the ridge R is about to end The weft is cut into

  As already mentioned above, in order to cut the weft completely uniformly, the plane on which the cutting operation is performed (hereinafter simply referred to as "cut surface") and the weft should be orthogonal to each other when the cutting is performed. Is desirable. In the illustrated embodiment, the cutting plane is the plane in which the rotary blade H is located, so this plane is parallel to the direction of the warp and perpendicular to the direction of the weft. Thus, according to the invention, an induction strip 1 is provided which guides the weft thread smoothly to the cutting device so that the inserted weft thread is completely perpendicular to the plane and thus parallel to the battling line B. The narrow rod 1 is fixed at the lower end in an adjustable position adjacent to the weir in the loom in an adjustable position, this narrow rod unfolds in a direction parallel to the recess of the weir R and is apparent in the front view of FIGS. 3 and 4 As shown in FIG. 1, it is sufficiently spaced from the outer edge R1 of the weir to be disposed across the cutting surface of the rotary blade H on the opposite side of the weir R. In one embodiment of the invention shown in FIGS. 1 and 3, the thin rod 1 is further secured at the upper end to the upper end of the weir R by an adjustable support 2 in order to improve the stability. An effective alternative solution is to integrate the thin rod 1 directly into the rod R by extending the upper and lower edges of the rod, but in this case the possibility to freely adjust the position of the thin rod 1 Consists of cutting The position of this rod is in fact uniquely determined at the time of manufacture of the crucible R.

  By virtue of this construction, the weft thread inserted in the shed during the movement of the yarn R, even in the region between the edge R1 of the ridge R and the fine rod 1 regardless of the position of the clamping gripper P in each case It is always kept completely parallel to the battling line B, but in practice always always slightly behind the batting line B, due to bulk problems. Therefore, the weft yarn is kept completely perpendicular to the rotary disc H when it reaches the cutting position, and is generated upstream because it is supported on one side by the thin rod 1 and the other side by the weir R in a balanced manner Cutting is always performed under optimal conditions, regardless of possible fiber variations. Thus, under these improved cutting conditions, the cutting member H can be adjusted to a position no more than 3 to 4 mm closer to the edge of the fabric being formed, and still a completely uniform weft end edge Is obtained.

  If the loom is intended for use with weft yarns which have remarkable elastic characteristics and exert a constant "springback" force after cutting, the cutting device according to the invention advantageously has an elastic holding element 3 and Integrally, this holding element takes the form, for example, of a wire spring which abuts against the opposite abutment surface 4 with a predetermined elastic force (only its end is shown for the sake of simplicity, a fastening clamp on the weaving machine (Not shown). Since the wire spring 3 and the abutment surface 4 are arranged such that their mutual contact surfaces are located on the advancing surface of the weft thread which is moved by means of the weir R and the thin rod 1, the weft thread will also be cut after it has been achieved. It is held in place against the abutment surface 4 by the elastic force of the wire spring 3 so that elastic contraction of the weft thread into the formed fabric is avoided. Therefore, since the holding action of the wire spring 3 spreads over the area before the cutting member from the cutting member B at least for the length of some wefts, when the holding action of the wefts stops, the wefts are surely in the fabric It is fixed by being incorporated in. The shape of the elastic holding element 3 is not limited, and instead of a wire spring, for example, depending on the type of weft yarn to be knitted, an elastic thin layer or other elastic holding device can be used. Also, the shape of the abutment surface 4 can be modified according to the needs of the particular fabric. Specifically, the abutment surface 4 can be constituted by a second elastic holding element opposite to the first elastic holding element 3 instead of the fixing element.

  From the above description, with regard to the time at which the cutting performed only at the final stage of the beating operation is carried out, and thanks to the guidance and guidance provided by the thin rod 1, the weft thread is completely against the cutting surface of the cutting device With regard to always being maintained vertically, and with regard to the fact that the weft end is maintained in the correct position until the weft is completely fixed in the fabric thanks to the holding action of the line spring 3 against the abutment surface 4 It is clear how the weft cutting device according to the invention fulfills the desired purpose. All this is achieved by means of a very simple and hence accurate, particularly effective cutting device construction.

  However, the present invention should not be considered as limited to the specific configuration exemplified above, but merely as an illustrative embodiment, without departing from the scope of protection of the invention as defined solely by the following claims. In addition, various modifications within the purview of those skilled in the art are possible.

Claims (10)

  A weft cutting device for a projectile loom having a holding function for weft yarn for a gripper loom or in flight, wherein both looms have, as components, a sley and a weir (R) integrated with the loom; And the weir (R) are of the type in which wefts are cut after insertion into the shed, and the weft cutting device comprises a plurality of clamping grippers (P) for each weft (T) on standby and weft cutting And a cutting member (H) provided with points, said cutting member (H) being arranged in a fixed position, said weft cutting point being a batting line (B) of said weir (R) on the fabric to be formed Said guiding means (1) for guiding the weft towards the cutting member (H) during the beating step further provided with weft yarn guiding means (1) substantially aligned with and integral with said weir (R) ) Of the weir of the weft cut surface of the cutting member (H) They are arranged in pairs side, weft cutting device.   A weft cutting device according to claim 1, wherein the weft yarn guiding means comprises a thin rod (1) which is adjustably fixed at the lower end to the sley of the loom at an adjustable position.   3. The weft cutting device according to claim 2, wherein the bar (1) is further fixed at its upper end to the upper edge of the weir (R) via a support (2) having an adjustable position.   2. The weft cutting device according to claim 1, wherein the guiding means consist of thin rods (1) fixed to the extensions of the upper and lower edges of the weir (R).   Weft cutting device according to any one of claims 2 to 4, wherein the thin bar (1) is parallel to the recess of the weir (R).   The weft cutting device according to any of the preceding claims, further comprising a first elastic holding means (3) for holding the weft against the abutment surface (4) through an elastic holding force.   The weft cutting device according to claim 6, wherein the elastic holding means comprises a wire spring (3) or an elastic thin rod.   A weft cutting device according to claim 6 or 7, wherein the abutment surface (4) is located in the same plane as the plane in which the weft yarn is moved by the weir (R) and the thin rod (1).   A weft cutting device according to claim 6, wherein the abutment surface (4) consists of a second elastic holding element which abuts the first elastic holding element (3).   7. A weft cut according to claim 6, wherein the holding action of the wire spring (3) extends from the front of the cutting member (H) over the score line (B) on the abutment surface (4). apparatus.

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