Shed-forming mechanism, weaving loom of jacquard type and method for adjusting the number or type of warp yarns of such a loom

Abstract

In a shed-forming mechanism for weaving loom of Jacquard type in which the position of certain warp yarns of the loom is controlled by means which are themselves controlled by a Jacquard system, there are provided, for at least one warp yarn, means for temporarily connecting this yarn on its position control means. The number or the type of warp yarns to be used is adjusted by cutting a warp yarn and by temporarily connecting it with its position control means, such as a heddle or the harness cord associated therewith.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a shed-forming mechanism and to a weaving loom of Jacquard type equipped with such a mechanism. The invention also relates to a method for adjusting the number or type of warp yarns of such a loom to be used for a sequence of weaving.

BACKGROUND OF THE INVENTION

[0002] In the domain of weaving looms of Jacquard type used for manufacturing carpets, it is known to use certain warp yarns to constitute the piles of a carpet, these warp yarns being delivered by the creel in which are supported reels whose number is equal to that of the piles. These warp yarns are unwound from these reels under the effect of traction thereof.

[0003] Such a weaving loom is generally equipped with a creel comprising yarns of different colours or types, and, as a function of the sequences of weaving envisaged, particularly as a function of the patterns of a carpet to be manufactured, the number of these colours or the type of these warp yarns may evolve. For example, from a creel provided with reels of warp yarns of ten different colours, it is sometimes opportune to weave with only eight colours of warp yarns. In that case, it would suit to be able to neutralize two colours of warp yarns for a future sequence of weaving.

[0004] Two known approaches are sometimes employed for such a neutralization.

[0005] The unnecessary yarns may be removed from the warp and rewound in the creel. When these warp yarns are to be used again, they must be reintroduced in the loom up to the beating point. Such an operation is long, tedious and, in practice, expensive. It is sometimes necessary to immobilize a weaving loom for up to three weeks in order to reintroduce these warp yarns.

[0006] The second known approach is more rapid to implement. It consists, by a modification of the weave obtained thanks to the Jacquard system, in incorporating the unnecessary warp yarns in the background of the carpet, arranging for them not to be visible. In that case, the unnecessary yarns correspond to a loss or waste of warp yarns which, when ten colours are reduced to eight, may represent more than 20% by weight of the warp yarns.

[0007] Similar problems may occur with Jacquard weaving looms used for weaving products other than carpets.

[0008] It is a more particular object of the present invention to overcome these drawbacks by proposing a shed forming mechanism which makes it possible to neutralize certain warp yarns of a weaving loom simply, reliably and economically.

SUMMARY OF THE INVENTION

[0009] To that end, the present invention relates to a shed forming mechanism for a weaving loom of the Jacquard type, in which the position of certain warp yarns of the loom is controlled by means which are themselves controlled by a Jacquard system, characterized in that, for at least one warp yarn, means are provided for temporarily connecting this yarn on the afore-mentioned means for controlling its position.

[0010] Thanks to the invention, the warp yarn may be neutralized by immobilizing it on its control means which may be a heddle or a harness cord associated therewith, which makes it possible not to incorporate this warp yarn in the product being woven, but without having to remove it from the loom. This avoids the subsequent steps of reintroduction of the yarn in the loom when it is to be used again for a future sequence of weaving. In practice, temporary connection means are provided for each warp yarn of a particular sub-group of warp yarns, for example for all those of a colour likely not to be used for certain patterns.

[0011] According to advantageous aspects of the invention, a shed forming mechanism may incorporate one or more of the following characteristics, taken in all technically possible combinations:

[0012] The temporary connection means are provided on a heddle presenting an eye for passage of the afore-mentioned warp yarn. In that case, they may be provided to comprise a zone of jamming of the yarn made on a branch of this heddle which extends from its eye. This jamming zone may be formed by a slit made in the afore-mentioned branch.

[0013] The temporary connection means are provided on a harness cord for controlling the displacement of a heddle presenting an eye for passage of the warp yarn mentioned above.

[0014] The temporary connection means comprise a sleeve threaded on the branch of the heddle or on the harness cord, mobile in its longitudinal direction and adapted to cover the jamming zone and that part of the yarn jammed therein.

[0015] An element is provided for keeping said warp yarn temporarily connected on its control means in a position disengaged from the shed.

[0016] The invention also relates to a weaving loom of Jacquard type, particularly a weaving loom intended for manufacturing carpets, equipped with a shed forming mechanism as described hereinabove. Such a loom is easier and more economical to operate than those of the state of the art.

[0017] Finally, the invention relates to a method for adjusting the number or type of warp yarns of a weaving loom of Jacquard type to be used for a given sequence of weaving, in which, when it is desired to neutralize a warp yarn for the following picks, the following steps are carried out, in which:

[0018] a) the warp yarn is cut between a heddle of which it traverse an eye and the beating point and

[0019] b) the cut end of that part of the yarn still engaged in the eye is temporarily connected on the heddle or on a harness cord for controlling the displacement of this heddle.

[0020] Thanks to this method, the neutralization of a warp yarm or of a series of warp yarns when articles to be woven are changed, may be effected rapidly, without involving long and tedious manoeuvres when the warp yarns or yarns must be used again in a subsequent sequence of weaving.

[0021] According to advantageous but non-obligatory aspects of the invention, this method may incorporate one or more of the following characteristics:

[0022] an additional step is provided in which the heddle is displaced towards an upper or lower position where it is maintained during the sequence of weaving in question.

[0023] an additional step is provided in which the yarn temporarily connected to its control means is kept in a position disengaged from the shed.

[0024] during step a), the yarn is cut between the reed of the loom and the beating point and, between steps a) and b), a step is provided in which the end of the yarn is withdrawn from the reed.

[0025] Finally, the invention relates to a method for adjusting the number or type of warp yarns of a weaving loom of Jacquard type to be used for a sequence of weaving in which, when it is desired to use for the following picks a warp yarn previously neutralized by a method such as described hereinabove, steps are carried out, in which:

[0026] f) the afore-mentioned end of the warp yarn is disconnected from the heddle or harness cord mentioned above,

[0027] g) this end is passed in the reed again, and

[0028] h) this end is joined to the fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention will be more readily understood on reading the following description of two forms of embodiment of a weaving loom and of a shed forming mechanism associated therewith in accordance with the invention, and of a method according to the invention, given solely by way of example with reference to the accompanying drawings, in which:

[0030] FIG. 1 schematically shows a weaving loom according to the invention.

[0031] FIG. 2 is a view on a larger scale of detail II in FIG. 1.

[0032] FIG. 3 is a view similar to FIG. 2 when a warp yarn is being neutralized.

[0033] FIG. 4 is a view similar to FIG. 2 when the warp yarn has been neutralized.

[0034] FIG. 5 is a view on a larger scale of a part of a heddle and of a harness cord of the loom of FIGS. 1 to 4.

[0035] FIG. 6 is a view similar to FIG. 5 for a mechanism in accordance with a second form of embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0036] Referring now to the drawings, the weaving loom M shown in the Figures is supplied with warp yarns 10 by a creel 12 in which are stored reels 14 from which the warp yarns 10 are unwound.

[0037] In order to render the drawings clearer, only four warp yarns 10 have been shown, it being understood that the number of warp yarns of such a loom may be several thousands, as a function of the size of the product to be woven.

[0038] In the embodiment shown, the loom M is used for weaving carpets T1 and T2 which, after having been woven, are separated from each other by means of a cutter 16 which cuts their piles P1 and P2.

[0039] The loom M is equipped with heddle frames (not shown), of which the vertical oscillation movement is controlled by a dobby or a cam mechanism, (likewise not shown). These frames serve to weave the background fabric of the carpets T1 and T2.

[0040] The loom M comprises a reed or sley 18 intended to regularly beat the manufactured fabric at the level of a beating point 20, after each pick has been introduced in the shed F in a direction substantially perpendicular to that of the warp yarns 10.

[0041] In order to weave the carpets T1 and T2, each warp yarn 10 intended to form the piles is controlled individually, in its vertical oscillation movement F1, by a heddle 22 provided with an eye 24 for passage of the warp yarn 10 in question. In order to render the drawing clearer, only four heddles 22 have been shown. Each heddle is fastened by its upper end 22a to the lower end 26a of a harness cord 26, the assembly of the harness cords 26 constituting the harness H of the loom M. The vertical displacement of the harness cords 26 is controlled, in manner known per se, by a Jacquard system 30.

[0042] When a warp yarn 10 is to be neutralized, i.e. no longer incorporated in one of the carpets T1 or T2 to be woven, this yarn 10 is cut in a zone Z1 included between the reed 18 and the beating point 10, as represented by a cross in FIG. 2. The end 10a of the part 10b of the yarn 10 which remains engaged in the eye 24 of the corresponding heddle 22 is then bent towards this heddle, as represented by arrow F2 in FIG. 3.

[0043] This end 10a is then temporarily immobilized on the heddle 22 by introducing it in a slit 22b made in an upper branch 22c of the heddle 22, this branch 22c connecting the eye 24 to the upper end 22a of the heddle 22. The introduction of the end 10a in the slit 22b is represented by arrow F3 in FIG. 5.

[0044] Once the end 10a is engaged in the slit 22b, a sleeve 32 of plastics material is slid along the branch 22c, as represented by arrow F4, so that this sleeve covers the slit 22b, to such an extent that the end 10a is immobilized on the heddle 22 by jamming.

[0045] The sleeve 32 remains in position at the level of the slit 22, as the total transverse section of the heddle is slightly greater at that level than in the other parts of the branch 22c.

[0046] The sleeve 32 is to be distinguished from the sheath 34 which is engaged and possibly retracted around the ends 22a and 26a, in order to guarantee the fastening of the heddle 22 on the harness cord 26.

[0047] The sleeve 32 may, by default, be positioned at the level of the slit 22b, in which case it is displaced, in the direction opposite that of arrow F4, in order to clear access to the slit before introduction of the end 10a, as represented by arrow F′4 in FIG. 3.

[0048] When the upstream part of the yarn 10, still engaged in the eye 24, has been immobilized on the heddle 22, the system 30 is controlled, in particular by computer programmation, so that the heddle 22 is brought near the position of top dead centre of its path, and even thereabove, as represented by arrow F5 in FIG. 4. The unused yarn 10 may be disengaged from the shed thanks to a cross-beam 38 disposed in the direction of the weft yarns between this yarn 10 and the used yarns, this cross-beam supporting this yarn above the shed. In this way, during the weaving sequence to come, the immobilized yarn 10 does not undergo efforts of friction by the other warp yarns which move both in the direction of the double arrow F1 and in a direction of advance towards the beating point 20.

[0049] In a variant, it is possible to provide that the zone of cut Z1 be located between the reed 18 and the heddles 22. In that case, part 10c of the cut yarn 10 is withdrawn from the reed 18 before the sequence of weaving to come is started.

[0050] When it is desired to re-use a previously neutralized yarn 10, the sleeve 32 is slid in order to access the slit 22b and to remove the end 10a of the yarn 10 in question therefrom. The end 10a is then introduced between the corresponding teeth of the reed 18 and this end is joined to the fabric previously manufactured.

[0051] The programmation of the system 30 is then modified so that the heddle 22 and the harness cord 26 are animated by a vertical oscillating movement F1 corresponding to the desired weave.

[0052] Weaving can then be proceeded with, using the yarn 10 in question.

[0053] According to a first variant of the invention (not shown), the means for temporarily connecting the end of the harness cord yarn on the heddle may be provided at the level of its lower branch 22d, i.e. between the eye 24 and its lower end 22e fast with a return spring 36. In that case, when the corresponding yarn 10 has been connected with the heddle, the latter is displaced to near the bottom dead centre of its path, in order to disengage the yarn from the shed. In that case, a cross-beam equivalent to the cross-beam 38 is advantageously arranged below the shed in order to keep the yarn 10 at a distance therefrom.

[0054] In the second form of embodiment of the invention shown in FIG. 6, elements similar to those of the first embodiment bear identical references increased by 100.

[0055] This embodiment differs from the preceding one in that the means for temporarily connecting the free end 110a of the part 110b of a warp yarn 110 engaged in the eye 124 of a heddle 122 are provided, not on the heddle itself, but at the level of the harness cord 126 associated therewith, in the form of a loop 126b in which is engaged the end 110a which is advantageously knotted at that level.

[0056] According to an optional aspect of the invention shown in dashed and dotted lines, a sleeve 132 of the type of sleeve 32 of the first embodiment, may also be used for covering the opening 126b and the end 110a which, in that case, is not necessarily knotted.

[0057] Other forms of embodiment of means for temporarily connecting the end of a warp yarn on its position control means, in its vertical oscillation movement F1, may be envisaged within the framework of the present invention.

Claims

1. A shed forming mechanism for a weaving loom of the Jacquard type, in which the position of certain warp yarns of the loom is controlled by means which are themselves controlled by a Jacquard system,

wherein, for at least one warp yarn, means are provided for temporarily connecting said yarn on said means for controlling its position.

2. The mechanism of claim 1, wherein said temporary connection means are provided on a heddle presenting an eye for passage of said warp yarn.

3. The mechanism of claim 2, wherein said temporary connection means comprise a zone of jamming of said yarn made on a branch of said heddle extending from said eye.

4. The mechanism of claim 3, wherein said jamming zone is formed by a slit made in said branch.

5. The mechanism of claim 4, wherein said temporary connection means comprise a sleeve threaded on said branch, mobile in its longitudinal direction and adapted to cover the jamming zone and that part of the yarn jammed therein.

6. The mechanism of claim 1, wherein said temporary connection means are provided on a harness cord for controlling the displacement of a heddle presenting an eye for passage of said warp yarn.

7. The mechanism of claim 6, wherein said temporary connection means comprise a sleeve threaded on said harness cord, mobile in its longitudinal direction and adapted to cover the jamming zone and that part of the yarn jammed therein.

8. The mechanism of claim 1, wherein it comprises an element for keeping said warp yarn temporarily connected on its control means in a position disengaged from the shed.

9. A weaving loom of Jacquard type, particularly a weaving loom intended for manufacturing carpets, equipped with the shed forming mechanism of claim 1.

10. A method for adjusting the number or type of warp yarns of a weaving loom of Jacquard type to be used for a given sequence of weaving, in which, when it is desired to neutralize a warp yarn for the following picks, it consists in the following steps of:

a) cutting said warp yarn between a heddle of which it traverse an eye and the beating point,

b) temporarily connecting the cut end of that part of the yarn still engaged in said eye, on said heddle or on a harness cord for controlling the displacement of said heddle.

11. The method of claim 10, wherein it comprises an additional step of:

c) displacing said heddle towards an upper or lower position where it is maintained during said sequence of weaving.

12. The method of claim 10, wherein it comprises an additional step of:

d) keeping said yarn temporarily connected to its control means in a position disengaged from the shed.

13. The method of claim 10, wherein, during step a), said yarn is cut between the reed of the loom and the beating point and, between steps a) and b), a step is provided in which:

e) said end of said yarn is withdrawn from said reed.

14. Method for adjusting the number or type of warp yarns of a weaving loom of Jacquard type to be used for a sequence of weaving in which, when it is desired to use for the following picks a warp yarn previously neutralized by the method of claim 10, steps are carried out, in which:

f) said end of said warp yarn is disconnected from said heddle or said harness cord,

g) said end is passed in said reed again, and

h) said end is joined to the fabric.