CH346963A - Elastic thread, process for its manufacture and apparatus for carrying out this process - Google Patents

Description

Elastic thread, process for its manufacture and apparatus for carrying out this process of this process.

It has been manufactured for many years, by a known process, elastic yarns with simple covering, consisting of a twisted rubber yarn and a covering roving wound in a helix around the rubber yarn. These yarns have been manufactured and used on a large scale, but they have not been used in all the industrial fields in which elastic yarns have been used, for example, yarns of this type, industrially produced , generally present an elongation comprised between 120 and 160 0/0. These yarns are generally only used to make low modulus, soft-touch woven elastic fabrics, for example fabrics used to make bathing suits.

Double-lapped elastic yarns have been manufactured and used on a large scale for many years, consisting of an untwisted rubber yarn around which two yarns are wound in opposite directions. Yarns of this type, produced industrially, present fordre elongations of approximately 100 to 400 b/o and can be made at will with a modulus of 61 ev6 or low. Since these double lap yarns can be made as desired, high or low elongation or high or low modulus, their applications have not been as limited as those of lap yarns. simple.

Elastic yarns of this general type, i.e. yarns comprising an elastic core, twisted or not, and a fibrous covering forming a sheath

on this nucleus, single or double, can be classified according to their elongations. Yarn having a fordre elongation of <B>115</B> 0/0 or slightly more is considered low elongation yarn and yarn having an elongation of about 400 1% or slightly less is considered as a high elongation yarn. A yarn having an elongation of about 200% would be classified as an intermediate elongation yarn. Industrially, large quantities of yarns having an elongation of 100 to 140% and especially yarns having an elongation of about 120% are used on large looms (weaving). In knitting, large quantities of yarns with intermediate elongation are used, that is to say comprised approximately between 180 and 220 %, and especially yarns with an elongation of approximately 200%, and in An hosiery uses large quantities of yarns having an elongation of 61ev6, that is to say about 300 to 400%, especially about 350%.

The single lap elastic yarn of the invention is well covered and balanced, and exhibits an elongation of at least 100%. It is characterized in that it consists of a twisted elastic core and a fibrous covering strand wound around this core, the ratio of the breaking length of the core per unit length of the stretched covered fit to the length of the covering strand per unit length of the relaxed covered fit being between 1.0 and 1.50.

The method which the invention comprises for the manufacture of this fit is characterized in that a 61astic core is twisted to an extent sufficient to balance the torque of the covering to be applied thereto, that this core is stretched and that him a

overlapping strand having a sufficient length for said ratio to have the indicated value.

The apparatus which the invention also comprises, for the implementation of this process, is characterized in that it comprises a device for supplying the elastic core, two driven cylinders making the first fibrous covering rivet at the point of covering. , at least one of the cylinders dtant such that the first elastic core passes between the cylinders without being serr6 by them, but in the vicinity of the covering, and a device winding the covering on the first core and taking up the first wire thus covered.

The accompanying drawing shows, by way of example, two embodiments of the apparatus which the invention comprises and illustrates implementations of the process which the invention also comprises.

fig. 1 is a diagram of a rubber yarn twister which may form part of an embodiment of the apparatus comprising the invention.

fig. 2 is a diagram of a first embodiment of the apparatus, which is used to make a single lap elastic thread by a spinning operation.

fig. 3 is a diagram of a second embodiment of the apparatus, used to make a single lap elastic yarn by a twisting operation.

fig. 4 is a cross-section of the clamping rolls which comprise these forms of execution of the apparatus, showing their construction and the relationship between the core and the cover strand.

fig. 5 is a section of a variant.

fig. 6 represents three wires in a relaxed state. fig. 7 shows these three yarns in the stretched state. fig. 1 shows an up-stroke twister which can be used to pre-twist a rubber core used in one form of single lap elastic yarn according to the invention. This twister crnnporte a rotating twisting pin 10 carrying a bobirre 11 of rubber thread. This yarn R comes out of bobirre 11 forming a ball resulting from the rotation of spindle 10. It passes through a pigtail 12 and between two cylinders. clamps 13 and 14. This yarn is twisted between the bobbin 11 and the cylinders 13 and 14. From these, the yarn goes to a take-up bobbin 15 to wind up there. The bobirre 15 is actuated by a roller 16, generally lined with cork, which rotates in contact with the rubber Carried by the bobirre 15 and thus causes the latter to rotate. As is well known, the speed of rotation of the roller 16 and the cylinders 13 and 14 is adjusted so as to wind the yarn R on the winder 15 at the desired tension.

The twister just described can form an integral part of an embodiment of the apparatus comprising the invention, in order to achieve a one-step operation.

fig. 2 shows one embodiment of the apparatus comprising the invention consisting of a spinning apparatus for covering a twisted elastic core, such as a rubber thread, in order to obtain a shape of execution of the elastic fit according to the invention. The apparatus of fig. 2 is of a common type, except for the front stretch rolls, which Fon will describe in detail below. As can be seen, this apparatus includes the bobbin 15 which has been transferred therein from the apparatus of FIG. 1. A roller 17, fitted with the usual cork lining, rotating in contact with the rubber thread Carried by the bobbin 15, is adjusted in rotation so as to regulate that of the bobbin 15 and, subsequently, the speed at which the The rubber thread R unwinds from the bobbin 15. This speed, in turn, controls the amount of stretching of the thread R as it leaves the bobbin 15. In the apparatus shown, the thread R passes between rollers stretch before 50 and 18 to go to a pigtail 19.

A wick 27, coming from bobbins 20 and 21, goes to a rear pair of drawing rolls 23 and 24. Passing through successive pairs of drawing rolls 23-24, 25-26 and 50-18, the wick is thinned in the usual way. When the wick emerges from between the cylinders 50 and 18, with the rubber thread R, it wraps around the latter, forming a fibrous covering sheath in the vicinity of these cylinders 50 and 18, after having traveled a small distance, for example 2 cm, from these cylinders. The covered rubber thread then passes into the pigtail 19 and goes to the slider 28 of a ring 29 to wind up on a bobirre 30 which rotates. As is common in twisting and spinning processes for making single lap elastic yarn, the bobbin 30 rotates to wind the lap onto the core in the opposite direction to the twist of the yarn R and, therefore, - sequence, to remove some of the twist from this yarn R during wrapping.

fig. 3 shows a second embodiment of the apparatus comprising the invention consisting of an apparatus for manufacturing RTIID="0002.0228" WI="6" HE="4" LX="1839" LY= "2051"> a form of execution of the 61astiqu.e single lap yarn according to the invention, by the process of twisting. In this process, the core is reopened by a thread rather than a wick. In the apparatus of FIG. 3, the bobirre 15' of oix unwinds the first rubber core, controlled by the first roller 17', supplies rubber thread R under tension. The rubber thread R coming from the bobbin 15' passes between two cylinders 31 and 32 to go to a pigtail guide 33.

The covering threads Y come from bobirres 34 and 35 passing on guides 36 and 37. The threads Y pass between the cylinders: 31 and 32. When the first fit R and the threads: Y leave the cylinders 31 and 32, the Y yarns are wrapped around the twisted rubber core to provide a single lap elastic yarn. This yarn then passes through pigtail 33 and goes to slider 38 of a ring 39 to wind onto a rotating spool 40. As is common in the process of making single lap elastic yarn, the The apparatus winds the threads on the rubber thread R in the opposite direction to the twist thereof and, during the covering, part of the twist of the thread R is removed.

fig. 4 represents the clamping cylinders quo present these forms of execution & ution of the device. These cylinders are cylinders 50 and 18 of the apparatus of FIG. 2 or the cylinders 31 and 32 of the apparatus of FIG. 3. As seen, these cylinders have shafts 41 and 41' on which sleeves 42 and 42' are fitted. On the latter are wound linings 43 and 43 'in a material 61astice tolle quo rubber. These cylinders are arranged so that the covering strand 51 (the roving 27 or the yarns Y) is caught between these cylinders to come to the covering point as the cylinders rotate.

In said embodiments of the apparatus according to the invention, at least one of these cylinders is made in such a way that the rubber thread R can pass between the cylinders without being squeezed by them. In the embodiment of FIG. 4, part of the gasket 43 has been removed and on the shaft 42 is mounted a grooved pulley 44, so that the wire R can pass between the cylinders in the groove of the pulley 44 without being clamped between the cylinders.

The devices described and shown are made and arranged so that the thread R and the covering material are brought very close to each other at the point of covering, without the yarn R being clamped where it is. approaches the cover material.

fig. 5 represents a variant of Fun of the cylinders allowing the wire R to pass between the cylinders without being squeezed between them. This cylinder has a shaft 41" carrying a sleeve 42" on which is wound a gasket 43". 44, a disc 45 is carried by the 42" shaft in this missing part. This disc 45 tapers towards the adjacent end of the 4-1" shaft giving a narrower bearing surface on which the wire R can rest. without being squeezed between the cylinders. Conveniently, the wire R is laid over the disc. 45 in the sense that it applies. against the first disc 45 by moving away from the end of the shaft.

Ort has found that the pulley 44 or the disc 45, having a smooth surface, but hard and resistant to abrasion, is advantageous for the passage of the delicate rubber thread, without abnormally chafing it. Advantageously, the pulley or disc can be made of nylon.

To make a wire, the core unwinding speed is regulated in relation to the speed at which the covering is fed by the clamping or driving cylinders in the following way: the arrival speeds are regulated by such that the ratio of (a) the breaking length of the core per unit length of stretched covered yarn divided by (b) the length of the covering strand per unit length of stretched covered yarn is between 1.0 and 1.50.

The table below gives the characteristics. structure of different forms of execution of the wire according to Finventio-n and some known son. In considering the figures in this table, it should be noted that they were obtained by length and weight measurements and, therefore, a slight error in measurement may have been multiplied in the figures. paintings. However, the figures are correct within the usual tolerances of the trade.

D is the length of the core at failure (E) minus the relaxed length of the core when this bare core is completely relaxed, but retains the residual torsion (B), divided by the relaxed length of the core (C), multiplied by by 100.

The residual tension B is the twist retained by the core in the covered elastic yarn.

F was measured in los, samples with covered yarn (samples 1 to 11) by removing the covering from the core and measuring its length. In the samples with cover roving (12 to 14), an 16 F was calculated by determining the length of cover provided by the front feed rolls to the cover machine at that length of elastic yarn, as a result of the difficulty of removing and measuring the wick, with little twist, on the core. Centimeters of cover per meter of relaxed yarn is the length of a single strand of cover in that length of yarn; of course, if desired, one can make the single lap elastic thread, as in 1a. fig. 2, using more than one strand in the overlap. In this case, the length is that of any one of the strands.

The most significant number in the table is G (E divided by F).

In all examples, above, except those 3, 6, 11 and 14, this ratio falls below about 1.5 and, in fact, between 1.0 and 1.50. It can be seen that at 11 and 14, an exceeds these values considerably and they are elastic threads with a single lap before and not in accordance with the invention. We see that wires 3 and 6 are slightly above the upper limit. These yarns have been made, using the apparatus described above, but in such a way that they do not exhibit the advantages of a yarn according to the invention; in general, they do not give satisfaction.

When the ratio varies in the range of 1.0 to 1.50, the characteristics of the. wires vary. When the ratio exceeds the limit of 1.50, the core begins to come to the outside of the yarn in the stretched state and, above this limit of 1.50, the yarn is considered

industrially as having the tops of the prior type single lap elastic yarn.

0n can make other interesting comparisons. For example, comparing samples 1 and 2 with 11, we see that 1, 2 and 11 have about the same length of lap per yard of yarn and about the same elongation. It will also be noticed that 11 n & essite about 50 u/o more core per meter of yarn than 1 and 2. Because of this excess core, the covering of 11 takes a central position as a core when the yarn and the core is pushed outward wrapping around the cover. The same comparison can be made between samples 3 and 4, between 6 and 7 and between 12 and 14.

Los fig. 6 and 7 demonstrate significant differences between yarn produced by the process described above and yarn produced previously. In the figures, A is a double-lapped elastic yarn as hitherto manufactured. As we can see by comparing figs. 6 and 7, this thread remains well covered in the extended state.

Yarn C is a single lap yarn made as hitherto. We see that this wire seems to be well covered in fig. 6. However, when stretched, the core winds outward at points such as 52. Yarn B is a yarn made by the process described above. By comparing figs. 6 and 7, it is seen that the thread remains well covered, even when it is stretched out. The most significant comparison that can be made is Gelle of wires B and C at Ntat etird in fig. 7.

The yarn produced according to the process described above, in addition to the savings in materials, which are evident from the foregoing, has other very interesting advantages. For example, assuming the same type and lap length in the new and old yarn and the same elongation, the new yarn has a higher modulus, Gar, in the new yarn the core is in a more stretched condition than in the old one. Moreover, since the core remains intact in the new yarn, a fabric made from it can be dyed better than a fabric made from the old yarn, since the rubber on the surface of the latter does not take not the dye and therefore gives the fabric a bario16 appearance. Moreover, when one knits or weaves the yarns, they are generally stretched; in RTIID="0005.0280" WI="3" HE="4" LX="431" LY="2138"> the old wire, the nucleus which came to the surface was not protected by the covering and, consequently, it frays in the loom or knitting machine and is damaged.

Claims (1)

CLAIMS I. Well-covered, well-balanced, single-lap elastic yarn exhibiting an elongation of at least 100%, characterized in that it consists of a twisted elastic core and a fibrous covering strand. wound around this core, the ratio of the breaking length of the core per unit length of the relaxed covered yarn to the length of the covering strand per unit length of the relaxed covered yarn being between 1.0 and 1 .50. II. Process for the manufacture of the yarn according to claim 1, characterized in that an elastic core is twisted to an extent sufficient to balance the torque of the covering to be applied thereto, this core is stretched and a strand wound thereon. covering having a sufficient length for said ratio to have the indicated value. III. Apparatus for carrying out the process according to claim 11, characterized in that it comprises a device for supplying the elastic core, two driven cylinders bringing the fibrous covering to the point of covering, at least one of the cylinders 6tant as the first elastic core passes between the cylinders without being squeezed by them, but in the vicinity of the covering, and a device winding the first covering on the first core and taking up the first wire thus covered. SUB-CLAIMS 1. A plastic yarn according to claim I, characterized in that the covered yarn has an elongation of 115 to 350<B>0/0-</B> 2. A method according to claim II, characterized in that in that a fibrous strand is advanced between two cylinders which hold it together and a twisted and stretched elastic core is advanced between the cylinders, very close to the strand, but leaving it free between the cylinders, and that the strand is wound on the elastic core immediately after they have left the cylinders. 3. Process according to claim 11, characterized in that the front clamping cylinders of a spinning frame are used as clamping rolls, and in that said fibrous strand used is a roving. TXF FR="8" WI="83" HE="13" LX="1076" LY="1885" SIZE="10" FONT="Times New Roman"> 4. Process according to claim II, characterizing in that the fibrous strand used is a twisted yarn, and in that a rubber core is used. 5. Apparatus according to claim III, characterized in that one of the cylinders is notched and the core passes through this notch. 6. Apparatus according to claim III and sub-claim 5, characterized in that the notched cylinder is provided in said notch with a pulley over which the core passes. 7. Apparatus according to claim III and los sub-claims 5 and 6, characteris6 in. whereby the cover is wound onto the core by means of a rotating spindle.