FR2587373A1 - Fabric edge formation installation for shuttleless looms - Google Patents

Abstract

The edge is formed with overhanging picks. The yarn ends of the picks inserted into a weaving shed are clamped yieldingly in a holding installation, which is positioned at a lateral distance from the fabric warp ends and coupled to the stroke motion of the reed. The holding installation is positioned on the reed and can be swung laterally via a parallelogram coupling. The rocker arms of the coupling can be driven via an arm, which swivels on a bearing fastened to the machine.

Description

 The invention relates to a device fitted to a shuttleless weaving machine or loom and intended to form a selvedge on a fabric with projecting milking threads, in which the ends of the trailing threads.

inserted into the shed are introduced between auxiliary warp threads of a separable provisional selvage, which extend at a certain lateral distance from the warp threads of the fabric, and are maintained by the latter.

 In the technical field of weaving, several possibilities are known for forming a selvedge on a fabric in looms without shuttle. One of these possibilities is what is called an auxiliary edge or temporary edge. In a loom without shuttle, this selvedge is either on one side only, that is to say on the side of the extraction of the weft threads, or on both sides, that is to say on the insertion side and on the extraction side. In such a temporary selvedge, a number of auxiliary warp threads are arranged laterally outside the main warp threads for the fabric itself. These auxiliary warp threads are also subjected to a movement of the crowd and the weft thread is inserted by its free ends between these auxiliary warp threads, then it is gripped and retained by the latter.

In this way, it is given birth by weaving a narrow strip of auxiliary fabric, which has the sole purpose of retaining or capturing the weft thread and of preventing a possible leap backwards from the end of this weft thread. . This auxiliary strip of fabric, or provisional selvedge, is then separated from the actual fabric. Such formation of a selvedge on a fabric, using a temporary selvedge, is svonllue, for example, according to the docusiciii : I) t: -A-2 t91 430
In the trades. In known weaving, we work, during the insertion of the weft yarn, with an individual auxiliary comb intended for the use of auxiliary warp yarns, where the main comb is kept longer for as long as necessary. protruding end of the weft thread extends from the edge of the fabric over the width of the sectioning gap, the width of the provisional selvedge, the inevitable distance between the outermost warp thread and the tip or the gripping device of the retracted weft thread insertion member, as well as on the remaining part which necessarily projects beyond the gripping device. The end of the weft thread, protruding above the edge of the fabric, constitutes with the above widths or distances a strong drop of weft threads which, when considered over a fairly long period of time, results in a large loss of production.

 To reduce this drop in the weft thread, a device is described in French patent application No. 83 13 851 (corresponding to patent DE-3 240 569) in which the device for retaining the ends of the weft threads, for example the temporary selvedge is coupled in synchronism with the striking movement of the comb, and, when the weft thread is stuffed by a striking movement, this retaining device can be moved further laterally, from a rest position located very close to the comb, so that a gap is formed between the fabric and the retainer, the ends of the weft threads are thus introduced into the retainer with elastic tension in their longitudinal direction.

 In this device, the sectioning interval is only formed when the comb is struck and, therefore, during the insertion of the weft itself and when the end of the wire is firmly held in the warp threads auxiliary of the provisional edge, it is possible to dispense with the width corresponding to this interval of twist When the linear comb accomplishes its lateral mfulvenent, the length of weft yarn necessary to form the sectioning interval is thus drawn from the fall which is located on the edge, which is in the provisional selvedge and which protrudes beyond this.

 The principle cited can also be applied when working without a temporary selvedge and the function of these temporary selvedges is fulfilled by another retaining device, for example by a clamp.

 In the embodiment of the known device, an auxiliary comb, by which the auxiliary warp threads of the auxiliary selvedge are drawn, is arranged on a comb holder and can be moved with this in a laterally arranged guide member. relative to the main comb. The lateral movement of movement is controlled by an arm, which acts by one of its ends on the comb holder to which it is articulated and which is mounted by its other end so as to be able to pivot in a bearing or journal fixed to the frame of the loom.

This embodiment is, however, less favorable for fairly large pivot angles of the arm, since the adjustable comb holder can become jammed in its guide member. It is certainly possible to guide the retaining device in a curved path around the tip of the introduction or gripping member of the frame, in withdrawal, for example a lance, but this curve is very flat and it does not bring so that little additional effect.

 Starting from a device of the kind mentioned last, the invention is intended to improve the lateral movement of movement of the retaining device so that it does not occur annoying jamming or other similar adverse effects, and also so that the circular path surrounding the end of the lance has a sufficient radius of curvature without harming the rest of the effectiveness of the device.

The invention therefore relates to a device fitted to a weaving loom without shuttle and intended to form a selvedge on a fabric with weft son projecting, the ends of the weft son inserted in the crowd being intrudui tes in; uri ositif tif retaining placed at a certain lateral distance from the warp threads of the fabric and being elastically held by this retaining device, which is coupled in synchronism with the striking movement of the comb, this retaining device being able, during stuffing of the weft thread by a striking movement, to be moved laterally outwards from a rest position located very close to the comb.This retaining device is connected, via an articulated parallelogram, to . so as to be able to be laterally offset, with the main comb and an oscillating connecting rod of the articulated parallelogram can be driven by an arm pivoting around a bearing or journal attached to the frame of the loom. According to other advantageous features of the invention
the bearing or journal, subject to the frame of the loom, is located in front of the rear rest position of the main comb, in the direction of the striking movement;
the position of the bearing or journal is adjustable; and
the position of the articulated parallelogram is adjustable on the main comb in the direction of its length.

The invention will now be described, by way of non-limiting example, with reference to the appended drawings in which
Figure 1 is a schematic plan view of the arrangement, so far usual, a provisional edge;
Figure 2 shows, in plan, the device according to the inventio-n; and
Figure 3 is a side view, on a slightly enlarged scale, of the device according to the invention.

 Figure 1 shows schematically in plan the arrangement, conventional until now, of a provisional edge. This figure shows a certain number of warp threads 1. The outermost warp thread on the edge of the fabric has the reference numeral 11. At a certain spacing S from these warp threads, there are auxiliary chain 2, of which the one located the furthest inside is referenced by 21. These auxiliary chain wires form the provisional selvedge and they are guided by an auxiliary comb 7. We see in the drawing, below the main comb 6, a weft thread 3 inserted, which is also held in place by a weft thread insertion member, for example by a gripping member or lance 5. A short 3 'end of weft thread protrudes beyond the lance clamping device 5. The finished fabric is indicated by the reference number 4. The striking or starting movement of the main comb 6 is marked with an arrow k. This comb then occupies its stop position 6 'illustrated by dotted lines. Correspondingly, the auxiliary comb 7 accompanies the main comb 6 and it is brought to its position 7 '.

The deployed end 3 ′ of the weft thread extends to a delimitation line 3a. The spacing S between the fabric and the temporary selvedge serves as a sectioning interval for the separation of the temporary selvedge.

 FIG. 2 schematically shows the device according to the invention, presented in a manner identical to that of FIG. 1. In this case also, an identical insertion width has been provided. Unlike FIG. 1, the auxiliary comb 7 is, during the introduction of the frame, very close to the main comb 6, represented (by dashed lines) in its rest position.

The weft thread inserter, i.e. the lance 5, is no longer retracted as far as in FIG. 1, but only up to a short distance behind the external delimitation of the litter temporary 2 occupying its internal position. During the striking movement A, the main comb 6 and the auxiliary comb 7 are moved, from the rest position 6a or 7a represented by broken lines passing through an intermediate position 6 "or 7", also indicated by islands broken lines, to reach the stop position, represented by solid lines in 6 ′ or 7 ′. The auxiliary comb 7 then performs a movement of lateral displacement V superimposed on the striking movement A.

 The lower part of Figure 2 again shows an individual weft thread. A shears 16 is disposed substantially next to the internal auxiliary warp thread 21. This shears sections the end of the inserted weft thread, as well as the provisional selvedge 2. The residue of thread which remains on the edge of the fabric can then possibly be tucked, in a known manner, into this fabric. This possibility is illustrated by the reference 3 ".

 We will now explain in more detail, with reference to FIGS. 2 and 3, the device intended for laterally moving the retaining device or the provisional selvedge 2. A support 13 is fixed, for example by means of screws 17, to the flange 20 of the main comb 6. The support 13 carries an articulated parallelogram 12. The two oscillating connecting rods 14 of the articulated parallelogram 12 are pivotally mounted at 13a and 13b on the support 13 and are connected at their free ends by an arm 15 to form the parallelogram. The arm 15 extends in the direction of the main comb 6 and carries at its end the auxiliary comb 7. The connection between the auxiliary comb 7 and the arm 15 is rigid, but removable, and can preferably be carried out by screwing. the outer connecting rod 14, located on the right in the drawing, is articulated an oscillating arm 8 which extends it. The other end of the swinging arm 8 is articulated in a bearing or journal 9 secured to the frame of the loom. A support for the bearing or journal 9 is represented by a dashed line in FIG. 2 and is designated by the reference index 19. This support can be subjected for example to a fixed guide 23 of the lance outside the crowd.

 During the striking process, the comb 6 is moved from; position r) has rest, passing through an interinetic position; '.- ire 6 ". i the p> s position 6' of stop. The oscillating arm 8 then pivots around fixed bearing 9, to pass from its rest position, not shown, via the intermediate position 8 "represented by a broken line, at the stop position 8 'represented by a solid line. The oscillating arm 8 then actuates the oscillating connecting rods 14 of the articulated parallelogram 12 first of all a little in the direction of the main comb 6 and then back to move them away from this comb 6. The auxiliary comb i then describes a curved trajectory 22 which, at starting from position 7a leads it first to position 7 "very close to the wires of the bottom chaste 1 then moves it away from this channel 1, outwards, to bring the comb to position 7 ' so as to form the sectioning interval S. The auxiliary comb 7 remains, in this movement, always parallel to the main comb 6 and it is neither inclined nor subjected to torsion. The aforementioned curved path 22 presents, due to the existence of the articulated parallelogram 12, a much more intense curvature than that possible due to the guiding in pure parallelism according to the aforementioned French patent application no. 83 13 851. The point of the lance 5 can then be in the state retracted from the introducer of the t oar, very close to the crowd or the main comb 6. The end of the projecting weft thread when the weft is introduced is therefore shorter.

In addition, when the auxiliary comb stops in its position 7 ′, the end of the curved trajectory 22 brings this comb far enough outwards so that a sufficient sectioning gap S is formed even in the event of a relatively short abutment trajectory of the main comb 6 and a small pivot angle of the swing arm 8.

 The position of the aforementioned curved path 22 can be adjusted by modifying the position of the fixed bearing or journal 9. To this end, it is feared to bring the bearing or pin 9 greater or less far in front of the rear rest position of the main comb 6. The possibility of adjustment is shown in FIG. 2 by the indication of the position 9 ′ of this link. Of course, the possibility of this adjustment is represented not only by a possibility of moving cement in stages, but also by a continuous movement, for example using a buttonhole. In addition to a modification parallel to the direction A of the striking movement, it is also possible to conceive of an offset in the direction of the frame or in the longitudinal direction of the main comb 6. This possibility is represented by the inclined position of the bearing 9 ' relative to position 9 of this bearing or journal.

 Another possibility of adjustment is given by an offset of the support 13 along the rim 20 of the comb.

For this purpose, provision is made, for example, in the support 13, a buttonhole 18 (FIG. 3) making it possible to offset, by means of the clamping screws 17, the support 13 parallel to the main comb in the direction of the frame.

The difference X between the lengths 3a of yarns in FIG. 1 and 3b in FIG. 2 makes visible the decrease in the waste or fall of weft yarn. This length
X allows, compared to the gain which can be obtained in the case of the known device described in the aforementioned French patent application no. 83 13 851, another economy by avoiding loss by fall. The same difference X also emerges from positions 5a and 5b of the tips of the lances in FIGS. 1 and 2. The articulated parallelogram 12 allows a smooth execution of the lateral movement of movement of the auxiliary comb 7 during the striking movement.

 It goes without saying that, without departing from the scope of the invention, a number of modifications can be made to the device described and shown.

Claims (4)

 1. Device equipping a non-shuttle weaving loom and intended to form a selvedge on a fabric with projecting weft threads, the ends of the weft threads inserted in a shed being introduced into a retaining device placed at a certain lateral distance warp threads of the fabric and being resiliently held in this device, which is coupled in synchronism with the striking movement of the comb and can, when the filling of the weft thread by a striking movement, be moved more laterally towards the outside from a rest position located very close to this comb, device characterized in that the retaining device (2) is mounted so that it can be offset laterally on the comb (6) by an articulated parallelogram (12) and in that an oscillating connecting rod (14) of the articulated parallelogram (12) can be driven by an arm (8) oscillating around a bearing or journal (9) secured to the frame of the loom.  2. Device according to Claim 1, characterized in that the bearing or journal (9), subject to the b ti of the loom, is located, in the direction of the striking movement (A), in front of the rear rest position of the main comb (6).  3. Device according to claim 2, characterized in that one can adjust the position of the bearing or journal (9) to bring it for example (9 ').  4. Device according to claim 1, characterized in that one can adjust in the longitudinal direction the position of the articulated parallelogram (12) on the main comb (6).