IL32205A - Production of mouline carpet yarns - Google Patents

Description

niay τη«» "ns* » Production of mouline carpet yarns OIANZSTOFF A.G.

Ci-30517 This invention relates to a process for the production of compressed mouline carpet yarns in which the yarn is guided through a compression chamber and then oorded.

So-called mouline yarns are widely used in the manufacture of floor coverings. These are yarns that have been twisted together from several, preferably three, individual yarns each of which has been dyed in a different colour after texturing. Unfortunately, the individual nature of yarns such as these gives rise to difficulties in that even minor deviations in the regularity of the structure are sufficient to cause differences in the dye finish of the end yarn so great that the yarn cannot be used. Irregularities of this kind occur for example in cases where the tension in the individual yarns differs where they meet at the cording station.

This problem Is well known and various attempts have been made to prevent this phenomenon known among experts as the "core effect". Thus, it has been proposed with texturing in mind, to arrange in front of the take-in mechanism of the compression chamber a yarn comb which engages deeply between the rollers and into which the yarns are individually placed. Means for electrostatically spraying the incoming and outgoing yarn should also be provided, their object being to make it easier for the yarns Issuing from the compression chamber to be separated. Apart from the considerable outlay involved, this process gives rise to various difficulties, in particular in inserting the yarns and in separating this occurs because this arrangement is unable to avoid the well known matting together of the individual yarns in the compression chamber. In addition, the unfavourable 32705/2 - 3 - satisfactory erimp. Tensions are generated during separation of the yarns as a result of the matting of the individual yarns, which was clearly promoted "by the interval, between the yarns during insertion, and this could not even be eliminated by parallel winding or even spreading of the yarns before the cording stage. Thus it is not possible to produce a satisfactory moullne yarn without the so-called core effect, 7 It has now surprisingly been fo^and that a very uniform mouline yarn can be produced in a single operation providing the yarns are guided strictly parallel to one another into the compression chamber without any intervals or gaps between them. The crimped readily separable filaments issuing from the compression chamber should then be guided for a minimum distance of about 0.Θ m at a certain lateral distance from one another, bent through an extremely large angle behind a last delivery unit and then guided through a yarn guide acting as the cordin station to the twisting spindle.

Accordingly, the invention provides a process for the production of compressed mouline yarn comprising the steps of guiding a plurality of individual yarns for forming the mouline yarn parallel to one another witnout any gaps between the individual yarns into and through a compression chamber comprising two take-in rollers at least one of which is hollow-ground; separating the yarns after they leave the compression chamber of guiding the yarns at a distance / t least 3 nun apart from one another through a delivery means; guiding each of the yarns under identical conditions through a large angle which is the same for each of the yarns; passing the yarns through a common 32705/2 \ .4 - · In a simplified process, the individual yarns, after leaving the compression chamber, are initially wound parallel to one another onto a cylindrical bobbin from which they are guided over a separating and guiding means to the cording spindle in the manner described. This, however, does Involve more in terms of machinery and time. In addition, the uniformity with which the yarns are guided in the cording station may in some cases be affected.

The yarns travelling through the unit by which they are combined form the edges of a pyramid whose cross-sections form strictly equal-sided geometrically similar polygons depending upon the number of yarns parallel to the base.

The invention also provides an apparatus for the production of compressed mouline yarn, the apparatus comprising guide means adapted to guide individual yarns for the mouline yarn parallel to one enother without any gaps between the individual yarns; a compression chamber comprising two take-in rollers at least one of which is hollow-ground in section; yarn separating means for separating the yarns after they leave the compression chamber, delivery means; means for guiding the yarns at a distance of at least 3 mm, apart from one another through the delivery means; a cording station including means for guiding each of the yarns under identical conditions through a large angle which is the same for each of the yarns; and means for winding the yarns together on to a cording spindle* The compression means is preferably divided into two chamber preceded by heating means. Preferably the yarn separating means is in the form of a yarn comb, arranged before the compression cham 32705/2 - 5 - yarns or an integral multiple thereof, the yarn guides being arranged at the vertices of an equilateral polygon; an additional collecting yarn guide common to all the individual yarns arranged at a distance from the plane defined by one said plurality of yarn guides at the centre of the equilateral polygon and in front of the latter as seen in the direction of yarn travel; and a balloon yarn guide symmetrically arranged with respect to collecting yarn guide and on the opposite side of the equilateral polygon to the collecting yarn guide.

At least one of the take-in rollers of the compression means has a hollow ground section which preferably begins 0.5 to 1 mm from the edges of the rollers and reaches a depth of from 0.008 to 0.06 mm and more preferably from 0.01 to 0.03 mm in the middle of the rollers. The depth of the hollow ground section is governed by the thickness and its width by the number of yams to be simultaneously introduced into the compression chamber. The depth: of the hollow ground section has to be selected from within the limits specified in such a way that every yarn is engaged without any slip. With thin yarns in particular, only one of the two rollers need have a hollow-ground section, whilst the second is plane-ground. Although it is possible to grind a flat groove whose depth corresponds to the limits specified above, into the surface of the delivery rollers instead of having a concave ground portion Whose cross-section corresponds substantially to a circular segment, the concave ground portion has proved to be more favourable* So far as the configuration of the cording polygon le concerned, it has been found that the height of the pyramid defined 32205/2 I times and preferably to between 0.8 and 1.6 times the diameter of the circle circumscribing the' said base. The collecting yarn guide is situated in front of the polygon forming the base, as seen in the directio of yarn travel. The cording station thus lies in the balloon yarn guide which combines the yarn arriving from, the Individual yarn guides forming the base and, in terms of arrangement, forms the counterpart of the collecting yarn guide. The so-called balloon yarn guide preferably moves up and down in synchronism with the ring rail, but with a shorter stroke as a result of which the distance to, the base of the cording polygon should be arranged in such a way that the shortest distance betwee the base of the cording pyramid and the balloon yarn guide is not much shorter than the distance separating the collecting yarn guide from the latter, and is preferably no shorter than 0.8 times the distance separating the collecting yarn guide from the polygon base.

Irrespective of whether the process was carried out in one or two stages, however, it was found in every test that strict parallel guiding through the compression chamber and maintaining the distances specified for, the arrangement of the yarn guides in the cording polygon together with the arrangement of the cording station, are neoessary for producing a uniform yarn.

The process according to the invention is Illustrated by the following examples :-EXAMPIE 1 A yarn of denier 570/32, doubled, was introduced into the compression chamber by means of a pair of delivery rollers which had a width of 7.5 mm. a hollow ground portion (concave) of 0.01 mm bein rovided in both rollers be innin 0 mm f 32205/2 ^ • 7 - * of the rollers. Accordingly, its width was 6.5 mm.

In a second test, a yarn of the same denier quadrupled was guided through the apparatus.

In both cases, it was found that the yarns issued from the compression chamber in a strictly parallel arrangement and were very easy to separate* The yarns were then delivered via appropriate revolving and conveying means to a cording polygon with four yarn guides in its base and were then passed on to a cording spindle* The distance of the four yarn guides from one another was 90 mm, whilst the distance of the collecting yarn guide from the base was 90 mm. The cording polygon was arranged in such a way that the shortest distance between the balloon yarn guide and the base was 120 mm.

In both cases, a highly uniform yarn was obtained.

EXAMPLE 2 Three yarns of denier 1 140/64 were introduced iiito the compression ohamber by means of two take-in rollers 10 mm wide which had a deep hollow ground groove 8 mm wide and 0.03 mm deep. In this case, too,, it was found that the yarns moved through the compression chamber in strictly parallel order and, on leaving the compression chamber, were very easy to separate.

The yarns were then delivered via-appropriate guiding and conveying means to a cording polygon with three yarn guides in the base surface, and were then passed on to a cording spindle. The distance of the three yams guides from one another was 95 mm, whilst the distance from the base of the collecting yarn guide was 100 mm. The cording polygon was arranged in such a way that the 32205/2 In this case, too, a highly uniform yarn was obtained.

An apparatus suitable for carrying out the process according to the invention is described in detail below with reference to the accompanying drawings, wherein:- Pig. 1 is a simplified illustration showing the delivery of the yarns through the cording polygon and the balloon yam guide to the ring twisting spindle.

Pig, 2 is a section through, and Figure 3 a plan view of, the hollow-ground take-in rollers of the compression chamber, and Pig, 4 ie an elevatlonal view showing how the yarn is guided from the last delivery roller to the oarding polygon and thence to the balloon yarn guide.

Means for the delivery of yarns to be compressed from supply bobbins through a compression chamber, preferably provided with two compartments, are known, and Pig. 1 merely illustra the second stage of a simplified embodiment of the invention. Supp bobbins 2 and 3 are rotatably mounted on a take-off stand 1 in such a way that the yarns 5 are run, off tangentially. The yarns lie in a traversing yarn separator 4 arranged just in. front of the supply bobbins and are delivered from this separator to a separating comb 6 which spaces them at the predetermined distance apart. They then pass over a guide roller 7 to a delivery cylinder 8and a separating roller 8· and thence to a cording polygon 9, As shown in Pig. 4, this comprises a collecting yarn guide 15 and yarn guides 16 which define the base of the cording polygon and which correspond in number to the number of yarns or to an inte gral multiple thereof. The collecting yarn guide 15 is arranged by the yarn guides 16, whilst the cording polygon as a whole is arranged above a balloon yarn guide 10 in such a way that it too lies exactly perpendicularly beneath the centre of the base of the cording polygon defined by the yarn guifes 16· In this way, the balloon yarn guide becomes a clearly defined cording station ensuring the uniformity of the yarn in the course of formation. The combined yarns are guided from the balloon yarn guide in the usual way through a ring traveller 13 on a twisting ring 12 to a package 11 mounted on a twisting spindle 14· The configuratio of the compression chamber take-in rollers is shown in more detail in Pigs* 2 and 3. Take-in rollers 19 and 20 have narrow cylindrical edges 24 and between them a symmetrical hollow ground portion 23 v?hich forms a bi-convex hollow duct 25 at that point where the edges of the rollers are in contact with one another. Following the usual procedure, .the two take-in rollers are in contact with.one another. Following the usual procedure, the two-take-in rollers 19 and 20 are arranged in, the compression chamber so that that point at which the edges of the two rollers.19 and 20 touch one another is covered by jaws 21 and 22 engaging past the rollers. The dimensions of the hollow duct 25 are such that even in the middle the yarn passing through is * safely packed and delivered into the compression chamber.

Fig. 2 shows the Introduction of the yarns into the compression chamber. They are introduced into a yarn guide 18 parallel to one another and .without any gaps between the individual yarns, the yarns being separated in the drawing solely in the interests of clarity. The yarn guide- 18 is arranged between the two take-in rollers 19 and 20· The yarns retain their strictly parallel disposition on account of the shape of the surface of the rollers. filaments 5» 5* and 5" Issuing from it are still strictly separate from one another and have not matted together.

If the number of yarn guides 16 is an integral multiple of the number of yarns 5» 5*» 5"> the yarns have to be inserted into the yarn guides 16 in such a way that the same interval remains between them. Accordingly, if for example there are six yarn guides 16 and three yarns 5 5' 5"> alternate yam guides 16 have to be missed out, whilst if there are only two yarns 5 and 5* two adjacent pairs of yarn guides 16 must remain free* The effect^of the measures provided by the invention was surprising* It had been possible in the past by arranging the yarn guides 18 sufficiently close to the point at which the take-in rollers 19 and 20 coincide, to guide the yarns 5# 5* 5" through the compression chamber in such a way that they could be separated again fairly easily. However, the difficulties in dyeing were still impossible to overcome, this being attributable to the fact that it was impossible to obtain a strictly parallel passage of the yarn in the compression chamber. Success also eluded the attempt to obtain an end product that was uniform in its dyeabillty and colour distribution even with the aid of the cording polygon 9.

Only with the combination of hollow-ground take-in rollers 19 and 20 in the compression chamber with the strictly parallel guiding of the yarn to a delivery roller 8, 8· and hence to the cording polygon 9 arranged with its axis of symmetry exactly in the spindle axis and above the balloon yarn guide, was it possible for the first time to eliminate all the difficulties that had provedt so troublesome in the past. - 11 - 52205/2 filament individual yarns with a denier of at least 120, are particularly suitable. The denier of the individual yarns is preferably not less than 250 to 300 den., individual yarns being the components for the composite mouline yarn forming the end product which themselves are multifilament yarns. .12 . 32205/2 :

Claims (2)

1. CLAIMS 1, A process for the production of compressed mouline yarn comprising the steps of guiding a plurality of individual yarns for forming the mouline yarn parallel to one another without any gaps between the individual yarns into and through a compression chamber comprising two take-in rollers at least one of which is hollow-ground in section} separating the yarns after they leave the compression chamber, guiding the yarns at a die- -tance of at least 3 mm apart from one another through a delivery means; guiding each of the yarns under identical conditions through a large angle which is the same for each of the yarns; passing the yarns through a common cording station; and winding the yarns together on to a cording spindle.

2. , A process as claimed in claim 1, wherein the compression chamber" comprises two compartments. 3· A process as claimed in claim 1, or claim 2, wherein the yarns, in being guided through an angle define the edges of a pyramid whose cross-sections parallel to its base, are equilateral, geometrically similar polygons* 4# A process for the production of compressed mouline yarn substantially as herein described with reference to the accompanying examples and/or drawings* 5# An apparatus for the production of repeatedly compressed mouline yarn, the apparatus comprising guide means, adapted to guide individual yarns for the mouline yarn parallel to one another without any gaps between the individual yarns; a compression chamber comprising two take-in rollers at least one of which is hollow-ground in section; yarn separating meane for separating the yarns 32205/2 * ( another through the delivery means; a cording station, including means for guiding each of the yarns under identical conditions through a large angle which is the same for each of the yarns; and means for winding the yarns together on to a cording spindle, 6« An apparatus as claimed in claim 5» wherein the compression means is divided into two chambers preceded by heating means* 7# An apparatus as claimed in any claim 5 or 6, wherein the yarn separating means is in the form of a yarn comb arranged before the compression chamber, in the direction of travel of the yarn* 8# An apparatus ae claimed in ah£ one of claims 5 to 7 wherein the cording station comprises a cording polygon having a plurality of yarn guides corresponding in number to he number of individual yarns or an integral multiple thereof the yarn guides being arranged at the vertioes of an equilateral polygon; additional collecting yarn guide common to all the individual yarns arranged at a distanoe from the plane defined by the said plurality of yarn guides at the centre of the equilateral polygon and in front of the latter as seen in the direction of yarn travel; and a balloon yarn guide symmetrically arranged with respect to collecting yarn guide and on the opposite side of the equilateral polygon to the collecting yarn guide, 9· An apparatus as claimed in any one of claims 5 to 8, wherein at least one of the take-in rollers of the compression chamber has a hollow ground portion which commences at from 0.5 to 1 mm from the edges of the roller and reaches a depth of from 0,008 to 0.06 mm in the middle of the roller. 32205/2 - 14 - 10· An apparatus as claimed in claim 9# wherein the depth of the hollow ground portion is from 0.01 to 0.03 mm. 11· An apparatus as claimed in any one of claims 5 to 10, wherein one of the two rollers is hollow-ground whilst the other is plane-ground. 12, An apparatus as claimed in any one of claims 5 to 11, wherein the or tooth take-in rollers of the compression means has a flat groove which begins 0.5 to 1 mm from the edges of the roller and is from 0.008 to 0.06 mm deep. 13· An apparatus as olaimed in claim 12, wherein the dept of the groove is from 0.01 to 0.03 nun deep* 14. An apparatus as claimed in claim 8 or claim 8 and any one of claims 9 to 13, wherein the height of the pyramid defined by the base formed by the said plurality of yar guides, the collecting yarn guide and the yarns travelling through, is from 0.2 to 2.0 times the diameter of a circle circumscribing the base, above its middle point. 15. An apparatus as claimed in claim 14, wherein the height of the pyramid is from 0.8 to 1.6 times the diameter of the circle circumscribing the base. 16. An apparatus as claimed in claim 8 or claim 8 and any one of claims 9 to'15, wherein the balloon yarn guide moves up and down in synchronism with the ring rail but with a shorter stroke and is never less than a minimum distance from the base of the cording pyramid which corresponds to 0.8 times the distance separating the collecting yarn guide from this base. 17. An apparatus for the production of compressed mouline yarn, substantially as herein described with reference to the