US2947136A

US2947136A - Twisting of continuous filament yarns

Info

Publication number: US2947136A
Application number: US723766A
Authority: US
Inventors: Robert G C Arridge; George A Clough; Pell Morris William
Original assignee: British Nylon Spinners Ltd
Current assignee: British Nylon Spinners Ltd
Priority date: 1957-03-30
Filing date: 1958-03-25
Publication date: 1960-08-02
Anticipated expiration: 1977-08-02

Description

Aug. 2, 1960 R. s. c. ARRIDGE ETAL 2,947,136

TWISTING OF CONTINUOUS FILAMENT YARNS Filed March 25, 1958 Inventors fioeier GRIP/mm Clmwrwc/c flak I065 GEORGE #45527 Claus y Nap/21s 14641.14: PELL 9 y 2 Z Attorneys 2,917,136 U 'rwrs TING or CONN "arm's FAILAHMRN nubertl G. A r ds an G ne A-HC oi s u Pq w ii i ii, E la an M r w l i 'Pr l, M lb u en tralia, assignors to British Nylon Spinners Limited,

rdm pao nnguna H v a Filed Mar. 25, 1958, Star. Nb. 723,766 Claims priority, as irant. Great lliitiiiii Mia 60', 1 957- The present invention concerns improvements inorie lating to the twisting of eohtinnousfilament arns, and has particular reference t'o the process ofiiptwis'tin g such yarns when composed of a plurality of filaments.

In the process of uii-tvviStih'g, asupply package in the form of a bobbin is rotated at high speed on'a Vertical spindle and the yarn is led off over the top end of the bobbin, through a balloon guide positioned at the required distance directly above the spindle, and is then wound up in a package such as "a cheese. The rapid rotation of the-bobbin causes the yarn to balloon between the point of take-off and the balloon guide; and, depending principally on the vertical position of the point of takeoff, the supply package geometry (i.e. the shape'and size) and the speed of rotation, the balloon formation at any time may be either single, or multiple in nature; That is to say that, for a multiple balloon, the yarn atany one instant between the take-elf point and-the balloon-guide will tracefout a roughly sinusoidal path; "Depending on the nature of the balloon, the. tension in the yarn in the balloon (but not the twist imparted) will vary; and. for multiple balloons; the tension may be half orv less than that found when the. yarn isin a singleballoon.

In such a process of up'rtwisting, it will be appreciated that the desired resultant twist is achieved only at or about the take-up point of theyarn on the receiving package, and th o h l rofi. Po nt f thetya rn, fromvth'e supp package to the take-up pQ nUhq amount of-twist present increases from zero to themaximum, h n Oneditficulty that is encountered when' the,yarn is required to be twisted to only a low-degr;ee',;e;g. between about 2 and about 1.0 turns per inch, is;thatjthe;amount of twist inserted in the, region of the take loif point may be insufiicient to; keep the filamntsbound tightly together, certainly when the yarn is in a multiple ballooning phase. As a result, loops of filaments comprising either single slack filaments, or a plurality of slack filaments, are

formed in the yarn atjodd intervals along its length, and the presence of these loops is often detrimental to the satisfactory use oftheyarn im -subsequent knitting, we'aving, braiding or other textile operations. I When inserting a high degree of twist insuch a yarn, the defect of looping does not normally occur, because the amount of twist in the lower region i f above, say, turns per inch for 60 denieryarns and below,'is suflicient to bind all the filaments firmly togetherinto onecoherent structure, With high twists, other difii culties,relating-to y talke-oif may occur, but theydo not concerntthe present invention, except insofar as the conditions, for, operation of the present invention should be such as to avoid such difiiculties.

The present invention jfor it s ObiQlc t the preyention of substantially all, orga1l,-;sl1h;l0ops;being formed vin a ldw twist multifilament yarn during-'up-twisting to a'lowdegree. l Y, M I I y Accordingly, inigeneral terms,- the invention provides, in pp r for p w ting y ns, mean tfcr adding at porary twist to yarn which is in the ballooning phase.

ired States Patent ice 4 23,947,135 Asa-acre The invention also comprises a process for upt'wisting a continuous filament yarn wherein a false twist is imparted to the yarn so as to reinforce the twist in that part of the yarn which is in the ballooning phase. The false twist should be such that individual filaments of the said yarn-are bound together sufiiciently firmly to prevent them from looping to any substantial extent. A total twist of some -30 turns per inch for yarns of 60 denier and below is preferred in the yarn in the ballooning phase. According to a convenient embodiment of'this invention which will be more fully described hereaftera temporary reinforcing twist is added in an tip-twisting process by means of an annular friction surface making contact with the outward-facing parts of the at a position at or just below a balloon guide. The effect of the ballooning motion of the yarn in contact with the friction surface is to cause the yarn to be rolled around the surface and thus to be rotated about its own axis. In this mannena false twist, reinforcing the true twist, is inserted into the successive lengths of yarn between the friction surface and the point of take-01f from the supply bobbin. Bya suitable choice of the nature of the friction surface and its positioning, this reinforcing twist can be made suflicient substantially to prevent any looping.

Conveniently, the friction surface can take the form of a rubber (natural or synthetic), or rubber-lined ring, through which the yarn is passed and with which the yarn makes contact just before its entry to the balloon guide. There will now be given a more complete description of the aforesaid embodiment with reference to the accom- 'p'anying drawings, in which: a

Figure l is a diagrammatic 'side'elevation, of the said convenient embodiment of the invention;

Figure 2 shows a combined balloon guide and ring holder used in this embodiment; H a

Figure 3- shows a rubber ring for fitting in the holder of FigureZ;

Figure4 is a section through the ring of Figure 3.

Referring to Figure 1, an upstanding spindle 1 is rotated at high speed and carries round with it a yarn package 3, Due to the speed of rotation, yarn 5 forms a balicon on being led upwardly through a balloon guide 7 positioned heightwise above the spindle. This guide 7 is formed by one end of a thick wire comprising a combined balloon guide and ring holder 9 (see also Figure 2) which is pivotally mounted on the machine at its other end. Within the ring-holder 9 is mounted a rubber (natural or synthetic) ring or amiulus 11 (see also Figures 3 and 4) which thereby provides means for imparting a false-twist to yarn as will become more clear hereinafter. Traverse mechanism 13, comprises a rod 17 pivot-ally mounted on a reciprocating shaft 15, and having a yarn guide 19 for laying the yarn directly on a take-up package (cheese) 21, which is driven by contact with drive roll 23, the above apparatus together comprising the 'yarn takeup mechanism. I p

The yarn is led upwardly from balloon guide 7 to a guide 25 on the rearward portion of the traverse mechanism 13, and thence is laid down on the cheese 21 by the guide 19 I V v Referring particularly to Figures3 and 4, it will be seen that the ring or annulus 11 has a rounded lip 27 where the '7 abovering 11, are shown diagrammatically since such distances should be selected to give the required angle of wrap of the yarn S'around the rounded'portion 27-of ring 11. This distance will depend on the nature of the material of ring 11 and on the desired amount of false twist to be inserted. The twist inserted by contact with ring 11 will be in the same direction as and will reinforce the true twist in the yarn in those successive portions of it between the ring and the package 3. That is to say that the twist on the supply side of ring 11 will extend back to the supply package 3. This twist, due to the forward motion of yarn 5, will disappear from the yarn almost immediately after the yarn has emerged above the ring 11, so that the yarn will be wound up with only the required amount of low twist in it say, between about 2 and about 10 turns per inch brought about by the conditions of up-twisting. The amount of false twist required .to be inserted will depend on the nature of the yarn, i.e. its composition, the number and the denier of the individual filaments, the presence or absence of size etc.; but should be such that, together with the true twist inserted,

the amount of twist in the ballooning yarn is at least 15 turns per inch, and preferably about 20-30 turns per inch. A very much higher total twist is undesirable owing to the take-off complications that are thereby introduced.

'It is, of course, possible to arrange that the ring is rotated so as to insert a greater or lesser amount of false twist in the yarn, depending on the direction of rotation, than would be the case if it were stationary. The direction of rotation would need to be contrary to that of the ballooning yarn if it were desired to increase the twisting effect of the ring. Yet again, the balloon guide itself can be adapted to hold a rubber grommet from which the yarn must be caused to emerge substantially axially, the grommet having a hole-size of sufiicient diameter to ensure that the yarn will have a rolling motion imparted to it by contact with the internal surface thereof.

The amount of false twist inserted by any given friction surface in any given process will be dependent on the nature of the friction surface, theangle of wrap of the yarn in contact'with the surface, and the tension in the yarn between the surface and the take-off point. The two latter functions will vary according to the mode of balloon effective at any given time. In practice, however, it is found that the variations are complementary, so that the value of twist tends to remain substantially constant and sufficient for the purpose if the nature of the friction surface is correct. By a sufficiently high positioning of the balloon guide and friction surface, it is possible to arrange that the balloon is always in a multiple phase, and thus cause the tension in the yarn to remain constantly at a very much lower figure than normal.

It may sometimes be desirable to arrange that the yarn I makes contact with the friction surface only under certain COHdIIIOIIS, e.g.- when the yarn is-leaving the bobbin from the upper half only of a supply package which is tapered at both ends. Otherwise, a re-entrant balloon may be caused to form at the lower end of the package and lead to snarling of the yarn. To achieve this with a rubber ring attachment, a second smooth metal ring, of slightly larger internal diameter than that of the rubber ring, may be mounted for limited heightwise reciprocatory motion, synchronised with the yarn take-off traverse motion, below the rubber ring. It is arranged that the metal ring, when in its lower position, shall contact the ballooning yarn in such a way that the yarn is removed from contact with the internal surface of the rubber ring; and the movement of the metal ring is timed so that it occupies its lower position during the time that the yarn is coming off the supply package at the lower tapered end-portion thereof. In this way, the rubber ring is prevented from operating during the time that the yarn is coming off the lower tapered end-portion, and the metal ring, which'may be chromiumplated, is too smooth either to affect the running of the yarn or to cause the yarn to rotate about its axis so as to insert false twist.

Any material having a sufiiciently high coefiicient of friction with the yarn concerned and having a sufiiciently durable nature is suitable for the friction surface described 5 above. Naturally, however, it should not be of a nature that might impair the strength or appearance of the yarn,

the use of such rings.

or might actually abrade the yarn so as to sever any filaments thereof. Vulcanised natural rubber with carbon black filler has proved satisfactory with synthetic linear polyamide continuous filament yarns of from 30 to 210 denier, having individual filament deniers of 3 or 6 denier. Prescollan polyester rubber, and neoprene synthetic rubber of from 50 to Shore hardness are possibly more suitable materials for the friction surface owing to their wearing qualities. It is found, also, that, due probably to the extra twist assisting in the actual withdrawal of the yarn from the supply bobbin, and due to the greater amount of time that the balloon is in a multiple phase, the tension in the yarn at wind-up is actually less-than in the ordinary case, and thus a softer cheese can be wound. This is advantageous in the case of nylon yarns, particularly, as it is desirable to wind the cheeses as softly as possible to allow for subsequent contraction of the yarn.

Other means of inserting false twist into the ballooning yarn may be employed, but they are not normally as convenient or simple as the preferred rubber ring. Such means may take the form of a conventional false-twisting spindle or of a rotating rubber bush, positioned either above or below the balloon-guide.

Example 1 Nylon 60 denier 20 filament yarn having &2 twist was uptwisted from a double taper drawtwist bobbin to '7VzZ turns per inch. The bobbin was rotated at 9,000 -r.p.m. on a vertical spindle, and the twisted yarn was wound up in cheese form at feet per minute. The wound length of the bobbin was 8 inches, and the distance between the top of the bobbin and the balloon guide directly above the spindle was 1% inches. Positioned inch below the balloon guide was a rubberlined'ring of vulcanised natural rubber with carbon black filler of /2 inch internaldiameter, which made continuous contact with'the ballooning yarn so as to insert false twist therein. The cheese so wound was softer than normal and had no loops of filaments therein.

'denier 20 filament yarn of /2Z twist was uptwisted from a double taper drawtwist bobbin to 72 turns per inch. The conditions were the same as in Example I with the exception that the ring was of neoprene synthetic rubber of 75 Shore hardness and of inch inner diam- Also running for the same period was a control supply bobbin but having no ring to insert false-twist. There 'were over 3 times as many loops in the uptwisted control yarn as there were in the yarn uptwisted through :the neoprene ring.

Example III Nylon 60 denier 20 filament yarn of zero twist on /2 ,lb. double-flanged bobbins was uptwisted to 5 turns per inch Z twist. The speed of the supply package spindles was 9,000 r.p.m., and the linear speed of the yarns wound up was feet/minute. 17 supply packages were uptwisted with inch inner diameter fneoprene rings of 60 Shore hardness positioned 1 inch below the balloon-guide inserting false twist in the ballooning yarns; and 17 supply packages were uptwisted without From the latter batch'of packages, three had to be rejected after uptwisting, on account ofmulti and single-filament loops None of the yarnsuptwisted with the use of the neoprene rings was defective in this manner.'

Although 60 denier nylon yarns havebeen referred to :in the above examples, it must be made clear that the invention isof use for other deniers of nylon; and that Qlher continuous filament yarns, such as those of Terylene polyester fiber of 75 denier have been success-' fully uptwisted according to the invention, which may, accordingly, be used with them also.

It is also possible for the invention to form part of an uptwister arrangement working at very hig arn throughputs of the order of 1000 feet/minute and in which only some 1 or 2 turns per inch are required to be inserted in the continuous filament yarn. In such circumstances, it may be essential to rotate the rubber ring in order that the necessary amount of false-twist may be inserted in the rapidly moving yarn.

What we claim is:

1. A process for uptwisting continuous filament yarn to about 2-10 turns per inch, comprising: withdrawing yarn upwardly from a rapidly rotating supply package to form a thread balloon; imparting a false twist of at least five turns'per inch to the succeeding lengths of yarn in the ballooning phase, such that the total twist of the yarn in the ballooning phase is at least fifteen turns per inch; and collecting the yarn.

2. A process according to claim 1 in which the amount of false-twist is such that the total'twist in the yarn that is in the ballooning phase is of the order of 20-30 turns per inch.

3. A process according to claim 1 in which the falsetwist is generated by passing the ballooning yarn in contact with a surface having a high coeflicient of friction with the yarn.

4. In a process for uptwisting continuous filament yam to about 2-10 turns per inch, including forming a thread balloonythe improvement comprising imparting a falsetwist of at least five turns per inch to that part of the yarn in the ballooning phase, such that the total twist of the yarn in the ballooning phase is at least fifteen turns per inch.

5. In a process for uptwistingcontinuous filament yarn to about 2-10 turns per inch, including forming athread balloon; the improvement comprising rotating the yarn in the ballooning phase about its own axis and thereby imparting a false-twist of at least five turns per inch to the same, such that the total twist of the yarn in the ballooning phase is at least fifteen turns per inch.

6. In a process'for uptwisting continuous filament yarn to about 2-10 turns per inch, including forming a thread balloon; the improvement comprising passing succeeding lengths of yarn in the ballooning phase in contact with a confining surface having a high coelficient of friction with the yarn, thereby imparting a reinforcing false-twist of at least five turns per inch to the yarn in the ballooning stage by rotating the same about its axis, such that the total twist of the yarn in the ballooning phase is at least fifteen turns per inch.

7. A process as in claim 5, wherein the false-twist is imparted to the yarn in the same direction as the true twist.

8. A process for uptwisting continuous filament yarn to about 2-10 turns per inch, comprising the steps of; continuously withdrawing yarn upwardly from a rapidly rotating supply package through a guide positioned above said package, whereby a thread balloon is formed; and causing a portion of the ballooning yarn to pass in contact with a surface having a high coefl icient of friction with the yarn, whereby the yarn is rotated by friction with the surface about its axis and a reinforcing falsetwist of at least five turns per inch is imparted to the yarn in the ballooning phase, such that the total twist of the yarn in the ballooning phase is at least fifteen turns per inch.

References Cited in the file of this patent UNITED STATES PATENTS 2,227,910 Pool Jan. 7, 1941 2,232,542 Lewis Feb. 18, 1941 2,249,777 Naumann et a1 July 22, 1941 2,258,899 Little et al. Oct. 14, 1941 2,318,162 Jones et al. May 4, 1943 2,718,111 Brown Sept. 20, 1955 2,803,105 Stoddard et al. Aug. 20, 1957 2,803,108 Stoddard et al. Aug. 20, 1957 2,803,109 ,Stoddard et al. Aug. 20, 1957 2,823,513 Vandamme et al. Feb. 18, 1958 2,838,903 Sutter June 17, 1958 2,878,637 Bacon Mar. 24, 1959 OTHER REFERENCES Frictional Properties of Nylon Yarn and Their Relatidn to the Function of Textile Guides, by Baird et al., page l01-page 111 of the Textile Institute Journal Pro- 5 ceedings, volume 46, January-June 1955.