IL81862A - Method and means for weaving plane fabrics and fabrics of that kind - Google Patents

Abstract

Process for producing fabrics, in particular multilayer fabrics on a loom, whereby in order to achieve extremely careful insertion of the picks even at high pickages, the pickages are above 20 picks/cm, the individual picks are not first beaten up, and beating-up is effected only after insertion of a complete set of picks consisting of several picks of a specified number.

Description

METHOD AND MEANS FOR WEAVING PLANE FABRICS AND FABRICS OF THAT KIND hT Aioa D»¾V¾O p>mog ο η η> κΐ> nwv This invention concerns a method and an arrangement for the production of fabric, more particularly of multiply fabric* by means of a weaving machine, which fabric is produced wholly or in its greater part from highly sensitive fibres such as carbon fibres, glass fibres or the like more - and furthermore the structure of a so produced fabric.

There are known - from British Patent Specification No. 2066 308 - three dimensional fabrics in the make of which carbon fibres or glass fibres are being employed. It is also known, in connection with carbon fibres to apply a course of motion which avoids beating of the material, thus taking in consideration extreme brxttleness thereof which is due to a tempeiature coefficient in the near vicinity of zero. 0056351 Further, the European Patent specification/is known which relates to a plane fabric consisting of high strength material, such as e. g. metal, carbon-fibre, aramides or of a mixture of these. These plane fabrics are made to assume a specific , predetermined shape.

Wilh known solutions the attainable result is not wholly satisfactory, since it has been found that with conventional weaving machinery each weft after insertion into the shed is beaten to the selvedge. At this step the rods of the reed rub, at each and every weft insertion - both at forward and also at rearward motion of the reed - along the warp threads. At high, especially at extremely high weft density, and the corresponding stroke of the reed there does exist a proportionality between the motion of the reed, warp density of weft and lift of the sley.

So a s to prevent rub- off da m age to highly sensitive warp material, it has become known to use po et-twisted warp threads or to e mploy fibre enveloped warp material. However, in many case s thi s leads to reduction of tensile strength or - as far as the fabric is concerned - to a reduction of its durability.

It i s the object of the pre sent invention - while eliminating the above mentioned disadvantage s - to provide a method and a device, a nd by the use of the se both - a fabric during the production of which no damage of highly sensitive warp threads, even at very high weft density.

Therefore, according to the invention there is provided a method for the production of f abric s, particularly multiply fabric s on weaving machinery, espe c ally with use of highly sensitive material, such as e. g. carbon fibre s, glas s fibre s, a r amide s and other technical yarns, in the application of which method weft density is above 20 wefts pe r c. m. , the individual wefts are initially not beaten in, beating being effected only after the insertion of a multiple, pre-determinable number of wefts forming a group.

The said solution has the advantage that it permits work with highly sensitive yarns at weft densitie s between 20 and beyond 150 wefts pe r cm whereby it is pos sible to produce warp and weft for highly dense fabrics of techni cal kind in three dimensional shape (multiply fabrics). Even at a high number of wefts the friction between rods of the reed and the warp threads is reduced to a minimum, thus preventing damage to the fabric. This is of spe cial importance in connection with extremely sensitive material for the warp threads, so that - as has now been found - no reduction in strength by damage to individual capillarie s of the threads would no longer be experienced. E specially in the case of the multiply fabrics an optimal pr oduct is obtained. When such fabric s are woven with selvedge zone s the warp threads o f which are le s s sensitive, the weft of which is beaten in after each insertion, a n interim product of which is optimally free of damage is obtained in which the selvedge is two-dimens ional which can easily be cut off, while the multiply part can be used for the purpose to which it is de stined.

The invention is shown in the annexed drawing and will be explained in detail in the following de scription. The re are shown in Fig. 1 the fractional and schematical illustration of a loom including the supplement according to the invention.

Fig. 2 part of a weaving machine in which the positioning and fixation of the reed holder are sche matically shown.

Fig. 3 parts within the range of the c ntrols of a machine ac cording to Fig. 1.

Rigid connections in the form of shaft- coupling between a gear shaft 1 and a reed shaft 2 are being substi t uted by coupling 3. C ontrol of the e couplings is synchronous by conventional means, such as perforated card from the dobby or by a generally known c olour sele cting arrange ment.

In this connection perforation = closure of coupling - reed beat of weft insertion no " = opening of coupling - no reed beat, or vice ver sa.

In view of the fact that the gear shafts - independently of this control - do execute the intermittent motion for the ; reed beat, the two outer sley swords are unseated so that they no longer serve as reed drive but only as reed supports.

At the coupling joints facing to the right hand or left hand gear which are taken along at the permanent, intermittent motion of the gear shafts, the holders of reed segment 4 (Fig. l) are fixed by screwing, the segment holders receiving the reed segments 9 (Fig. 1) at the width of the selvedge.

The reed segments which operate immediately at the right and the left of the reed perform - after every weft insertion - the beating in towards the right or left selvedge the warp threads of which consist of non sensitive material.

By this arrangement it results that every weft thread -whenever no regular beat is performed - is laid down at about 1-3 cm in front of the selvedge.

Corresponding to once chosen texture it is possible to insert several wefts, which - forming together a weft group - are beaten up after closure of the couplings. By corresponding control of the position switch of the colour selector (not shown) by means of ;tbe main switch 8 (Fig. 2) the opening and closure of the couplings occurs only when the reed is at rest at its rearmost position.

An exact positioning as well as arresting of the reed carrier at open coupling is effected by the electric.- magnetic holders 6 with adjusting plate 7 (Figs. 1 and 2), the electrical switching arrangement being thus designed that the electro-magnetic holder and the coupling function synchronourly.

The principle of periodic beating in of the reed has to be adjusted relative to individual texture formalities. This principle is particularly suited for fabrication of multi layer fabrics which are designed such that periodically several shaft changes are effected, solely from above downwardly or from below upwardly.

The object of maximal safe guarding the warp material will be obtained as the number of reed beats is smaller in relation to the number of weft inserts.

The number of reed beats in the form of a weft group which igroup is beaten as a unit towards the selvedge is dependent on the texture formation and could be minimisable to two and maximally more than ten weft inserts.

As many wefts can be inserted without beating in the reed as change of shed occurs without warp threads crossing.

This is the case 1) especially with multi ply fabrics with which the wefts are inserted in several planes, the change of shed occurring only from above downwards or only from below upwardly Z) at the succession insertion of two or more wefts into the same shed.

In order to create a shed with crossing warp threads, it is necessary to beat in the reed.

It has now been found that the structural features of the ready fabric which are due to the fact that lateral marginal zones are subject to be beaten after each weft insertion, while the central is beaten only after insertion of a group of wefts of a certain size dees not effect the ultimate use of the fabric e specially in the case of technical fabrics. For the sake of adjustment to special uses or for optimation of the relat ion volume: strength the marginal portion which consist of normal, less sensitive warp threads could be cut off wholly or partly.

! It is remarked that all novel features appearing in the ^description and/or depicted in the drawing are integral to the invention, even when not particularly mentioned in the claims.

Claims (4)

- 7 - 81862/2 We claim:

1. A method of producing a fabric which has warp and weft threads, said warp threads being made of a I delicate material and said weft threads being present in an amount of at least 20 weft threads per cm of warp threads, said method comprising the steps of (1) mounting warp threads made of a delicate material on a loom having a main reed, (2) forming a shed between said warp threads on said loom, (3) inserting without beating a plurality of weft threads in said shed, (4) beating together said plurality of weft threads with said main reed of said loom, and (5) repeating steps (2), (3) and (4).

2. A method of producing a fabric which has warp and weft threads, said warp threads being made of a delicate material and said weft threads being present in an amount of at least 20 weft threads per cm of warp threads, said method comprising the steps of (1) mounting warp threads made of a delicate material on a loom having a main reed, (2) forming a first shed between said warp threads on said loom, (3) inserting without beating a weft thread in said first shed, (4) forming a second shed between said warp threads on said loom, (5) inserting without beating a weft thread in said second shed, (6) beating together said weft threads with said main reed, and (7) repeating steps (2), (3), (4), (5), and (6). - 8 - 81862/2

3. A method of producing a fabric which has warp and weft threads, said warp threads being made of a delicate material and said weft threads being present in an amount of at least 20 weft threads per cm of warp threads, said method comprising the steps of (1) mounting a first set of warp threads made of a delicate material on a loom having a main reed and first and second auxiliary end reeds on opposite sides of said main reed so that said first set of warp threads extend through said main reed, (2) mounting a second set of warp threads made of a robust material on said loom so as to extend through said first auxiliary end reed, (3) mounting a third set of warp threads made of a robust material on said loom so as to extend through said second auxiliary end reed, (4) forming a shed between said first, second and third sets of warp threads, (5) inserting a weft thread in said shed, (6) moving said first and second auxiliary end reeds to beat associated portions of said weft thread, (7) repeating steps (4), (5) and (6) at least one time, and (8) moving said main reed to beat an associated portion of said weft threads.

4. In a loom for producing fabrics from delicate materials, said loom including a main reed having opposite ends, first and second transmission shafts, and a main reed driving shaft, the improvement wherein said loom includes first and second auxiliary end reeds respectively positioned adjacent said opposite ends of said *r»ain reed, and first and second clutches respectively connected between said first and second transmission shafts and said main reed driving shaft, said first and second clutches being respectively connected to said first and second auxiliary end reeds to simultaneously move said first and second auxiliary end reeds independently of said main reed. * * *