EP0007543B1 - Loom with weft cutting device and such a device for use therein - Google Patents

Description

The invention relates to a weaving loom according to the preamble of claim 1.

Weaving machines provided with a weft cutter device are known inter alia from documents US-A-4,077,438; DE-C-1,083,756; FR-A-2,277,916; FR-A-1.566.536 and DE-A-1.710.291.

The document FR-A-1.566.536 relates to a trade in which the cutting movement of the weft cutter device is obtained as the result of two movements: the movement of raising and lowering of the scissors themselves, controlled by a cam, and cutting by means of scissors by a sliding cam.

In addition, the document DE -: - A-1.710.291 mentions a weft cutter device with double control: a gripping and cutting movement by a sliding lever controlled by an eccentric.

In general, the known weft cutters are of relatively complicated operation and construction.

The object of the invention is to eliminate these drawbacks and to offer a weaving loom with a weft cutter device in which the loss of weft yarn on each pick is relatively low while the weft cutter device can however be maintained relatively simple construction.

To this end, the weaving loom according to the invention meets the conditions as defined in the characterizing part of claim 1.

In a particular embodiment of the invention, the transmission by rod between the support of the cam follower and the chisel, comprises at one end a connecting rod which is fixed, at a certain distance from the axis of articulation of the support, articulated around an axis parallel to this axis of articulation, on the aforementioned support.

Preferably, the articulated or pivoting attachment of the rod to one end of the rod transmission on the support of the cam follower is formed by a shaft with respect to which at least one of the elements formed by the aforementioned rod and the support can rotate, shaft which can be moved in the longitudinal direction relative to at least one of the last aforementioned elements.

In this embodiment, it is possible in a simple way with the same means intended to open and close the weft scissor, to move the latter according to the direction of the width of the loom, in order to adapt for example this weft scissor the width of the fabric.

In an advantageous embodiment of the invention, the rod transmission between the follower support and the weft chisel has at one end a rod which is positively connected to one of the knives of the weft chisel and which is therefore articulated about the axis of rotation about which the knives can pivot relative to each other, relative to the other knife.

In a preferred embodiment of the invention, the weft cutter device comprises a clamping part and means for applying the latter elastically against one of the knives.

In this embodiment, the weft cutter also acts as a weft presentation device for the gripper, so that no auxiliary mechanism is required for this presentation.

The invention also relates to a weft cutter device intended for use in a weaving loom according to one of the preceding embodiments.

• La figure 1 est une vue en élévation latérale d'une partie du métier à tisser avec dispositif coupe-trame suivant l'invention.
• La figure 2 est une vue en coupe suivant la ligne II-II de la figure 1.
• La figure 3 est une vue en plan de dessus, à grande échelle, du ciseau à trame du dispositif coupe-trame du métier à tisser illustré à la figure 1.

Other details and particularities of the invention will emerge from the description below, given by way of nonlimiting example and with reference to the appended drawings, in which:

• Figure 1 is a side elevational view of part of the loom with weft cutter device according to the invention.
• Figure 2 is a sectional view along line II-II of Figure 1.
• FIG. 3 is a top plan view, on a large scale, of the weft chisel of the weft cutter device of the weaving loom illustrated in FIG. 1.

In the various figures, identical references designate similar elements.

The weaving loom illustrated in the drawings is of a known type with pliers and bars with rigid pliers. For the sake of simplification, the loom will be described below and illustrated in the accompanying drawings only to the extent necessary to illustrate the invention.

The loom includes a drive shaft 1 which is supported in the frame 2 and is driven by a motor not shown in the drawings.

On an auxiliary shaft 3, which can be actuated by an alternating pivoting movement using a known transmission not illustrated in the drawings from the drive shaft 1, is mounted the rose lever 4, which carries at the upper part the leaf 5 and the ros 6. Opposite the latter are mounted two clamp bars 7, which each carry a clamp 8. These clamp bars 7 and clamps 8 are part of the weft introduction mechanism which introduces a weft thread into the crowd or interval of the warp. The first clamp 8 grabs on one side of the loom, the weft thread which is unwound from a reel and transmits it, in the middle of the loom, to the other clamp 8 which pulls the thread even further through the crowd . The ros lever 4, the leaf 5 and the ros 6 can be driven in a back-and-forth pivoting movement relative to a fabric table 9 mounted on the frame 2 and which supports the fabric already formed.

On the side of the loom from which the weft thread is brought into the crowd and where therefore, with each pick, the weft thread is driven by the first clamp, there is a weft cutter mechanism which, when the thread of weft has been completely pulled through the crowd, cut this weft thread so that the clamp, during the next pick, can again bring a free end of the weft thread through the next crowd. The weft cutter mechanism consists of a weft chisel, generally designated by the reference 10, and by a transmission between this chisel and the drive shaft 1, a transmission which controls the opening and closing of the chisel to frame.

As can be seen in particular from FIG. 3, the weft scissor 10 comprises a fixed knife 11 which is fixed by two bolts 12 at a certain distance from a fixing piece 13. The latter is itself fixed by bolts 14 and nuts 15 to leaf 5, immediately next to ros 6. Between the fixed knife 11 and the fixing piece 13 is the movable knife 16, which is rotatably mounted relative to the fixing piece 13. On the side of the movable knife 16 opposite the stationary knife 11, pressure is exerted by a clamping piece 18 which partially penetrates into an opening 19 of the fixing piece 13. A spring 20 pushes this clamping piece out of the opening 19 , with his head against the knife 16.

The articulated fixing of the movable knife 16 on the fixing piece 13 is obtained by means of a lever 21 of the aforementioned transmission. The knife 16 is positively secured by bolts 22 of one end of the lever 21, which end is articulated on a shaft 24 screwed firmly by one end into the fixed knife 11. This shaft extends in the direction of the frame, so that the movable knife 16 can be moved in a vertical plane extending parallel to the warp threads. A pressure spring 23 is arranged around the shaft 24, between a plate 17 fixed to the end of this shaft 24 and the movable knife 16, and it pushes the latter against the fixed knife 11. It is obvious that the bolts 12 must not hinder the movement of the knife 16 relative to the stationary knife 11, nor the corresponding tilting of the lever 21.

The end of the lever 21 remote from the weft chisel 10 is provided with a groove 25 extending in the longitudinal direction. In this groove 25 penetrates a shaft 26 which extends parallel to the shaft 24 and which connects the lever 21 to a second connecting rod 27. The latter consists of three parts which can be screwed into one another, which allows you to adjust the length of the connecting rod. The lever 21 and the connecting rod 27 form a rod transmission between the movable knife 16 and the support 28 of a cam follower 29. The latter is a wheel which circulates on a cam disc 30. The latter is fixed against a wheel toothed 31. The latter and the cam disc 30 are mounted together in free rotation around the auxiliary shaft 3. The toothed wheel 31 meshes with a toothed wheel 32 of the same dimension which is integral with the drive shaft 1.

The support 28 has approximately the shape of an inverted T. One end of the tail is hingedly attached by means of a small pin 33 to one end of the connecting rod 27. At the location of the junction of the tail and the head of the T, the support 28 is fixed articulated by a hinge pin 34 to a support 35 which is fixed to the auxiliary shaft 3 and is therefore also fixed relative to the rose lever 4. The hinge pin 34 therefore oscillates back and forth together with the leaf 5 and the ros 4 around the shaft 3. On one end of the head of the support 28 approximately in the shape of a T, the cam follower 29 has been fixed in rotation by means of a small pin 36. The other end of the head is fixed by means of a small pin 37 to a piston 38 which penetrates by one end into a cylindrical opening 39 of the support 35. Between the bottom of the opening 39 and the piston 38 is situated in . the opening 39, a pressure spring 40 which pushes the piston 38 outwards and therefore ensures that the cam follower 29 remains constantly in contact with the cam disc 30. The assembly formed by the support 35, the support 28, the transmission constituted by the lever 21 and the connecting rod 27 and the weft knife 10 accompanies the oscillation of the ros lever 4, of the leaf 5 and of the ros 6. Since the cam disc 30 also rotates continuously and that the cam follower 29 circulates on this cam disc 30, the support 28 will have to perform an alternative oscillation around its hinge axis 34 relative to the above-mentioned assembly. This oscillation is transmitted via the lever 21 and the connecting rod 27 to the weft chisel 10. In the position of the support 28 illustrated in the figures, the movable knife 16 is in its lowest position and the weft knife 10 is therefore closed. In this position, the ros 6 is in its rearmost position, that is to say the furthest from the tissue. During the pivoting of the forward oscillation of the ros 6 and due to the oscillation of the support 28, the movable knife 16 is caused to pivot via the connecting rod 27 and the lever 21 and therefore the chisel frame 10 is open. A guide plate 41, which is mounted in front of the fabric table 9 on the frame 2, pushes the weft thread into the open chisel. The cam disc 30 is constructed such that immediately after the movable knife 16 is pivotally returned to its initial position. Therefore, the weft thread is first pinched between the movable knife 16 and the clamping piece 18, then it is cut. When the ros 6 has reached its most forward position, the weft scissor 10 is completely closed. The part of the weft thread which has just been introduced into the crowd is then completely free from the part of this wire from the supply or supply coil. The most forward end of this last part is still in the chisel, between the movable knife 16 and the clamping piece 18. When returning to its rearmost position of the ros 6, the part of the weft thread which extends between the chisel 10 and the supply reel is thus offered to a clamp 8, so that the latter can again grasp the weft thread in the immediate vicinity of the cut front end of the last aforementioned part weft thread, in order to bring it during the next phase in the crowd. Due to the fact that the weft scissor 10 is mounted in the immediate vicinity of the ros 6, the cutting of a weft thread having just been introduced into the crowd takes place in the immediate vicinity of the selvedge and the part of this thread weft still coming from the reserve reel is also gripped by the clamp in the immediate vicinity of the cut end. The weft cutter mechanism therefore also forms a mechanism for the presentation of the weft yarn to a clamp, so that this presentation does not require any particular or additional mechanism. The weft loss is therefore extremely limited.

While the toothed wheel 32, and therefore also the associated toothed wheel 31, the cam disc 30 and the support 28 with the cam follower 29 cannot be moved in the longitudinal direction of the shafts 1 and 3, the weft chisel 10 can, in fact, be moved in this direction to allow adaptation of the cutting mechanism to different widths of fabric. This is obtained in a simple manner thanks to the fact that the small axis 33, by means of which the connecting rod 27 is hingedly connected to the support 28, can slide in its longitudinal direction relative to the support 28. The connecting rod 27 is located on one side around an end of small diameter of the minor axis 33. On this end is screwed a nut 42 intended to hold the connecting rod 27 in position. The other part of the minor axis 33, which therefore has a larger diameter, has a relatively large length and slides to penetrate through an opening 43 in the support 28. In this way, the cutting device described above can be adapted to very different fabric widths and, when the fabric width is changed, adapting the weft cutter mechanism is very simple. If when changing the width of the fabric, we replace the ros 6, we simply have to move the fixing part 13 of the weft chisel 10 and mount it in the correct place on the leaf 5. Therefore minor axis 33 then slides relative to the support 28, so that the transmission by rod between the weft chisel 10 and the support 28 remains ensured.

Claims (12)

1. Loom, with weft-cutting device (10), said loom comprising a frame (2), a driving shaft (1) supported inside said frame (2), a batten (5) mounted on said frame (2) with a to-and-fro swinging capacity, means (21, 27, 30, 31) to swing the batten (5) alternately and a weft-feeding mechanism (7, 8) to feed a weft into at least one shed or interval, while the weft-cutting device (10) cooperates with the weft-feeding mechanism (7, 8) and comprises a weft shear proper with two knives (11, 16) movable relative to one another, and means to open and close said weft shear, loom in which the weft shear (10) is mounted on the batten (5) and moves together with the swinging thereof, said means to open and close said weft shear comprising a cam disk (30) rotatably mounted on the loom, a transmission (31, 32) between the cam disk (30) and the driving shaft (19) to drive said cam disk, a cam follower (29) which rides on the cam disk, a support (28) on which said cam follower is mounted, which support is hingedly mounted on the batten (5) to convert a swinging motion of the support (28) into a folding-back of at least one knife (16) from the weft shear, said loom being characterized in that the cam disk (30) is rotatably mounted about an axis common with the rotation axis of the batten (5), and the means for swing alternately the batten (5) also cooperate with the weft shear (10) to open same, a rod transmission (21, 27) being provided between the support (28) and the movable knife (16) from the shear (10), said knife being positively controlled by the rod (21).

2. Loom as defined in claim 1, characterized in that the cam disk (30) is mounted to rotate freely on the auxiliary rotation shaft (3) from the batten (5).

3. Loom as defined in either one of claims 1 and 2, characterized in that the rod transmission (21, 27) between the support (28) for the cam follower (29) and the weft shear (11, 16) comprises on the one end, a link (27) hingedly connected some distance away from the support hinge axis (34), about a small shaft (33) extending in parallel relationship with said hinge axis, to said support (28).

4. Loom as defined in claim 3, characterized in that the hinged connection of the link (27) at the one end of the rod transmission, to the support (28) for the cam follower (29), is formed by a small shaft (33) relative to which at least one of those elements comprised of said link and the support (28), can rotate, which small shaft (33) is moable along the lengthwise direction thereof relative to at least the one said elements.

5. Loom as defined in any one of the preceding claims, characterized in that the rod transmission (21, 27) between the support (28) for the cam follower (29) and the weft shear (10) comprises at the one end, a lever (21) positively connected to the one knife (16) from the weft shear, and which is thus hinged about the rotation axis about which the movable knife (16) can swing relative to the fixed knife (11).

6. Loom as defined in either one of claims 3 and 5, characterized in that the rod transmission (21, 27) between the support (28) for the cam follower (29) and the weft shear (10) is comprised of a link (27) which is hingedly connected some distance away from the support rotation axis, to said support with a lever (21) which is so hinged as to be slidable over a very short distance inside the end of the link (27) and which is fixedly connected to the one knife (16) from the weft shear (10).

7. Loom as defined in any one of the preceding claims, characterized in that the one part of the rod transmission is formed by the small shaft (33), and in that the link (27) is adjustable in the length.

8. Loom as defined in any one of the preceding claims, characterized in that the weft-cutting device (10) comprises a clamping part (18) and means (20) to press said part resiliently against the movable knife (16).

9. Loom as defined in claim 8, characterized in that the weft shear (10) comprises a fastener (13) which is secured to the batten (5) and to which is connected the fixed knife (11) from the shear (10), while the movable knife (16) is mounted between the fixed knife (11) and the fastener (13), the clamping part 18 being resiliently mounted on said fastener (13) and being pressed against the movable knife (16).

10. Loom as defined in any one of the preceding claims, in which the cam disk (30) is mounted to rotate freely about the auxiliary shaft (3) from the loom, and the transmission between said cam disk (30) and the driving shaft (1) comprises a wheel (31) fixedly connected to the cam disk (30) and having the same rotation axis, and transmission means (32) between said wheel and the driving shaft (1).

11. Loom as defined in claim 10, characterized in that the wheel (31) which is connected to the cam disk (30) is a gear wheel and the transmission means between said wheel and the driving shaft are comprised of a gear transmission (31, 39).

12. Weft-cutting device, used in a loom as defined in any one of the preceding claims.

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