FR2512082A1 - PROCESS AND DEVICE FOR THE MANUFACTURE OF TRACKS ON CHAIN KNITTING MACHINES - Google Patents

Abstract

The invention makes it possible to produce with high productivity, in a wide variety of forms, colours and widths, woven chenille possessing good plucking (picking) and abrasion resistance.

Description

 The present invention relates to the manufacture of tracks on warp knitting looms, in particular on laces with lace braids comprising thread guides for weft and warp threads for the production of the intermediate product, using 'a cutting device and means for twisting the cutting product.

 The caterpillar consists of rows of fringe stitches and of weft threads linked by the latter.

 This chenille is preferably used as a decorative thread in the manufacture of flat textile products.

 The object of the present invention is to produce, in a single operation and with a high yield, good quality tracks on looms with lace braids.

 I1 is known to make tracks on weaving looms (patent DE 373 565) in which the intermediate product is cut after its weaving to be shaped then.

 I1 is also known to produce tracks by twisting on particular trades (DE-OS 2 345 541).

The chenille effect is then obtained by fancy yarns twisted in retaining yarns.

 Since in this type of caterpillar the small pieces of weft thread are only held by twisting the warp threads, these small pieces of thread are easily released from their connection at the slightest stress.

 In order to remedy this undesirable release of the small pieces of weft thread, it is known to tie them by hand or on looms with lace braid in the stitches of a row of stitches (patent DE 477 705).

 This method of manufacturing the tracks is very expensive because it requires several separate operations, to cut the weft threads, to bind them in the row of stitches and then to twist the latter.

 This manufacturing process also does not make it possible to obtain a great resistance to tearing and to wear because the small ends of weft thread introduced transversely to the branches of the meshes can only be held in place loosely. This drawback appears particularly when using threads of hard or smooth material for the row of stitches.

 The object of the invention is therefore to create a method and a device for its implementation which make it possible to produce, in a single operation, a knitted chenille having a great resistance to tearing and to wear.

 This result is obtained, in accordance with the invention, by a method which is characterized in that any number of weft threads laid in opposite directions is linked by at least one warp thread in a continuous fringe weave. The weft son bonding is performed so that each mesh links in the cusp of the weft son laid in opposite directions. When we use yarns of material of different shape and color for the weft, the most varied effects can be obtained in the knitted chenille. The weft son laid in opposite directions, by a row of continuous fringe mesh, can be carried out over the entire working width of the loom braid. The spacing of the rows of stitches then determines the diameter of the knitted track.

 The row of stitches further increases the strength of the binding of the folded weft threads when a knitting thread of elastic material is used.

 The intermediate product thus formed is then cut between the rows of stitches. To this end, circular knives are provided between the rows of stitches which, being arranged longitudinally relative to the latter, cut the intermediate product into rows of stitches carrying small ends of weft yarn. The intermediate product is brought to the circular knives mounted on a shaft, by a guide rail, to allow separation exactly in the middle.

 The flat chenille thus obtained is printed, by known methods, an S or Z twist, so as to create a knitted chenille of circular section.

 The device for implementing this process is a warp knitting loom, in particular a loom with lace braid, in which a yarn guide for the warp yarn is associated with each hook and which comprises at least two guides. thread for the weft threads and possibly offset relative to each other as well as a shaft carrying the circular knives and arranged below the knitting area and a twisting device mounted after the loom.

 For the production of a knitted chenille comprising weft threads laid in opposite directions and rows of bangs, a thread guide for the warp thread and at least two thread guides which can be offset one with respect to the other for the weft threads are associated in the direction of exit to each hook.

 Between the knitting area and the boring rolls there is a feed guide rail which is adjustable horizontally and vertically in the direction of the plane of the hooks as well as perpendicular thereto. This rail brings the intermediate product under tension to the cutting device, arranged downstream, to allow precise cutting of the intermediate product.

 A cutting device is positioned centrally between the hooks and below the knitting area, immediately after the guide.

 Thanks to the arrangement of the cutting device at this location, it is possible to divide the intermediate product into flat tracks immediately after the knitting operation on the lace braid loom.

 To transform the flat knitted chenille into a circular section chenille, a twisting device composed of a winder associated with each hook, and provided with a twisting device with a fin or a corresponding ring, is mounted downstream of the chopped off.

 Various other characteristics of the invention will also emerge from the detailed description which follows.

 An embodiment of the object of the invention is shown, by way of nonlimiting example, in the accompanying drawing.

 Fig. 1 is a schematic representation of the arrangement of the threads in the knitted intermediate product.

 Fig. 2 is a schematic representation of the arrangement of the wires in the flat track.

 Fig. 3 is a schematic representation for the manufacture of a knitted chenille.

 The intermediate product 1 is composed of weft threads 2 laid to occupy at least two intervals delimited by the needles and of weft threads 2 'laid to occupy also two needle intervals and which are linked by the rows of continuous fringe stitches 3. The flat track 11 obtained by cutting the intermediate product 1 along the line is composed of the weft threads 2; 2 'which are tied firmly in the row of bangs 3.

 The lace braid loom for manufacturing the tracks comprises, associated with each hook 71, at least two thread guides 21 for the weft threads and a thread guide 73 for the knitting thread. A cutting device 6 is arranged downstream of the guide rail 5 which is located below the knitting area 7. The guide rail 5 is adjustable horizontally and vertically in the direction of the plane of the hooks as well as perpendicular thereto. in order to be able to bring the intermediate product 1 under tension to the cutting device 6. The cutting device 6 is arranged in such a way that the intermediate product 1 is cut along line 4 between the rows of meshes 3. Immediately after the cutting device section 6 is the dispcs, t - f of torsion 8 which, by being equipped with a fin or ring torsion device, prints on the flat track 11 a torsion in the form of S or Z so as to obtain a knitted chenille of circular section.

Claims (4)

RESELL ICAT IONS  1 - Method for making tracks on warp knitting looms, characterized in that  - the knitting of the intermediate product (1) and the cut in flat chenille (11) as well as its twisting are carried out in a single operation;  - the weft threads (2, 2 ') placed in opposite directions are linked at their overturning zone by a row of continuous fringe stitches (3);  - immediately after the knitting area (7) the intermediate product (1) is cut in the middle between two rows of stitches (3), along the line (4), to obtain flat tracks (ll); and  - the flat track (11) is transformed into a round section track by torsion in a torsion device (8).  2 - Method according to claim 1, characterized in that one uses for the binding preferably weft son (2, 2 ') in an elastic material.  3 - Method according to claim 1, characterized in that the diameter of the track is determined by the spacing of the rows of meshes (3).  4 - Device for implementing the method according to claim 1, characterized in that the guide rail (5) is arranged so that it is adjustable horizontally and vertically in the direction of the plane of the hooks as well as perpendicularly to this.