US2254895A

US2254895A - Method for curling yarn

Info

Publication number: US2254895A
Application number: US224868A
Authority: US
Inventors: Jr Andrew Langstaff Johnston
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-08-15
Filing date: 1938-08-15
Publication date: 1941-09-02
Anticipated expiration: 1958-09-02

Description

Sept., 2, 1941. A. l.. JOHNSTON, JR 2,254,895

METHOD FOR URLING YARN Filed lAug. l5, 1938 l ATTORNEYS .Patented Sept. 2, 1941 UNITED STATES PATENT vOFI-ICE METHOD FOR CURLING YARN AndrewlLangstaile Johnston, Jr., Plainfield, N. J.

Application August 15, 1938, Serial No. 224,868

11 Claims.

'I'he present invention relates to a process for producing a substantially permanent curl or kink in yarn and like materials and to apparatus-for use in practicing the process.

The method heretofore most commonly em,- ployed commercially for curling yarn consists in combining a number of yarns as, for example, twenty to fifty, into a bundle, twisting the bundle under not too great tension until, as the twist increases, the bundle forms into a nearly continuous helix. Thegyarn so twisted is steeped (boiled oi) in boiling water or steam or other solvent with or without the addition of setting agents to set the curl. In the case of mohair yarn which is practically the only yarn curled on a commercial scale this steeping requires from six to eight hours at substantially boiling temperature to produce a permanent set of the curl. Ordinarily the yarn is dried while still twisted and then untwisted, the whole process requiring some ten or twelve separate operations. The long steeping required in this process to set the curl causes a considerable deterioration of theyarn, reducing the tensile strength about 20% during the rst hour and about 5% for each additional hour. The elongation properties suier an even greatervdeterioration and after a seven hours steeping the physical properties of the yarn' are depleted to the extent of 50% and this is `reiected in the wearing quality of the woven fabric. Furthermore, the yarn shrinks to the extent of 5% or more, thus correspondingly increasing the amount of yarn necessary to produce a given yardage.

In the operation of this process the limit to the length which it is practicable to curl is about 1200 yards, requiring tying where greater lengths are required in weaving. All things considered,

the speed of production is decidedly limited, the product is inferiorand thecost is high. These disadvantages limit the sale of curled yarn fabrics.

The present invention has for an object to prol vide an improved process for curling yarns which will produce a superior product and which can be operated expeditiously and economically.

Another object is to provide a process which will produce a uniform curl.

Another object is to provide a process which Another object is to provide a process whereby 55 shrinkage of the yarn during treatment is eliminated.-

Another object is to provide a process whereby the yarn will be slightly stretched during treatcurling which will cause the iinal product to be of the best quality.

\A further object is to provide a process in which the steeping operation can be accomplished in a shorter time.4

A still further 4object is to provide for improved apparatus for use in curling yarn.

'I'he invention provides a process wherein a bundle of yarns is curled and while held under tension is steeped and dried and thereafter the tension is removed and the yarns untwisted. In the process to be more particularly described for the purposes ofillustrating the principles of the invention a bundle of yarns is twisted and simultaneously wound about an incompressible mandrel which conveniently may be in the form of a. wire large enough to serve the purpose of a substantially rigid mandrel for winding the yarn and yet suilciently small and flexible to be conveniently coiled about a spool for convenience in further handling. In this form there is no tendency to tangle and great lengths can therefore be effectively and conveniently handled. The yarn thus twisted and coiled isv steeped as in previous processes, with this difference th'at` during the steeping operation it is so held on the wire mandrel as to prevent substantial shrinkage and as it is thereafter dried it stretches somewhat so that its final length is about 5% greater than before its original treatment.

'I'he degree of stretch or elongation can be controlled to some extent by varying the tightness of the twist and the degree of tension with which the yarn is wound about the wire mandrel.

The'degree and character of the curl produced can be considerably modii'ledoto suit requirements by ,varying the number of yarns ir. the bundle.- l

the degree oftwist and the diameter of the wire mandrel.

The optimum degree of twist and direction of twist can be determined by experiment-Tests made demonstrate that for most yarns the direction o'f. twist should be such as to reduce the twist which is imparted to the yarn in the doubling operation, that is to say the twist for curling should tend to untwist the yarn.

Certain definitel advantages such as relative uniformity of character and size oi' the curl ofthe several yarns in one'bundle are obtained by twisting the bundle once for each turn or wrap around the wire.

Actual practice of the invention has demonveniently obtained when the yarn is wound on a Wire mandrel with such tension as can readily be applied and the yarn steeped as herein described.

It is to be noted that the 5% gain in the length of the yarn when treated in accordance with the process of the present invention is to be contrasted with the 5% loss in length of the yarn treated by the process of the prior art and produces an effective gain in length of weavable yarn of about The new process, furthermore, produces a superior yarn in that when the yarn in maintained under tension as described the several fibres of the yarn shrink evenly thus avoiding the condition previously obtaining in which some fibres of the yarn shrink excessively and in use take more than their share of the tension and are readily broken.

Comparative abrasive wear tests of fabric woven from yarn curled by the new process and similar fabric woven from yarn of the vsame count curled by the process of the vprior art has shown the former to have far better wearing qualities. The yarn curled by the new process alsoshows a considerably superior covering of the pile due to the superior type of curl produced. In other words, the stretching of the yarn, thus producing a curled yarn of slightly less weight per thousand yards, is morev than compensated for by the superior character of the curl obtained.

It has been found that the curl can be set in a considerably shorter timeby the process herein described than when the yarn is curled by the process heretofore used. Furthermore, yarns which could not heretofore be satisfactorily curled by the commercialprocess are given a satisfactory permanent curl by the improved process. Mohair yarn can be curled by steeping for about one-third or one-half the time previously found necessary, for example' for 2 to 4 hours. The curl in cellulose acetate yarn can be set by steeping in boiling water for about fifteen minutes.

Ordinary wool yarn should be steeped about 2 to 4 hours.

Cotton and regenerated cellulose (as-viscos yarns are preferably'impregnated or at leastA vto fix the curl. c

wrapped rmly on the wire core causes a squeezing pressure on the fibre and at the same time causes, in effect, a stretching of the bre which tends to force out the iiuid in the minute cell pockets in the fibres of the yarn, thus collapsing them and causing the yarn quickly to assume a permanent curl or kink. The provision whereby the yarn is given the correct twist, that is to say the better direction and the best degree of twist, before steeping also contributes materially to the eiliciency of the steeping and reduces the time necessary. Whatever the reason for the results obtained, careful testshave demonstrated that the time of steeping is greatly reduced, the deterioration oi' the yarn is correspondingly reduced and a curled yarn of better physical properties is obtained by the process of this invention. Comparative tests havel shown a thirty to forty per cent greater tensile and elongation strength in yarn curled by thenew process as compared with the prior art process hereinabove described.

The entire lot of yarn as -wrapped on the wire can be introduced at one time into the steeping tank and treated for the desired period of time, or the yarn on the wire may be fed slowly through a steeping tank the length of wire in the tank and the speed of feed being such as to provide the desired treatment. `As the wire leaves the steeping tank it may be passed through a drying chamber and immediately unwound in a suitable machine, thus providing a continuous operation. It can even be unwound before drying to advantage in some variation of the process.

The method of twisting the yarn and wrapping it uniformly on the wire mandrel avoids tangling o! the yarn and resultant difilculties in untwisting.

The invention further provides apparatus for effectivelytwisting the bundle of yarns, winding the twisted bundle on the wire mandrel for treatment and after treatment unwinding and untwisting the same and rewinding the separated yarns on a suitable spool or spindle.

For the purposes of disclosure an apparatus embodying principles of the invention and` adapted for use in practicing the process will be described, for the purposes of which description reference should be had to the accompanying drawing forming a part hereof and in which- Figure 1 is a view partly in side elevation and partly in central longitudinal section showing the illustrative apparatus,

\ Fig. 2 is a plan view of the same, and l Fig. 3 is an enlarged detail view showing the wire core with a bundle of yarn twisted and wound thereon.

`lThe drawing is largely diagrammatic and intended only to illustrate principles of the apparatus without an attempt to provide an optimum mechanical construction.

'Y lustration comprises an unwinding cradle 5 for Itis believed that the principal reason thatr.

the set of the curl can be produced eectively by steeping for a shorter time is that the yarn is under tension in curled form and ineect the fibres are stretched during the shrinking. It is believed also that the tension caused by removing curled and treated yarn from the wire mandrel and -a winding cradle 6 for applying a fresh charge oi.' yarn to the wire for treatment;

A shaft I driven by the motor 8 supplies power to the machine. The cradle 5 is rotatably mounted in the pillow blocks 9 and Illvsecured to the main casing 'Il and is positively driven from the shaft '|by a chain gearing I2. A'yoke l5 s rotatably or iloatinglymounted in the cradle 5 in bearings which are co-axial with the bearsteeping as the yarn tends to shrink while ings of the cradle. The cradle, therefore, may

mandrel 25 with a fresh charge ofcurled yarn is wound. Both cradles rotate in the same direction and both yokes are weighted to prevent rotation thereof with the cradles. The wire mandrel is led from the spool I1 through

guides

26, 21, 23 and 29 to the spool 24 on which it is wound. The spool 24 is driven by the motor 30 through a suitable friction belt gearing which will maintain suilicient tension on the wire but which will yield to prevent excessive tension. As shown, a yieldable friction clutch 3| is provided for the Purpose of permitting adjustment of the tension.

the wire. Fig. 3, indicates the condition of the yarn a as twisted and wound on the wire 25. A reverse twist of the bundle is to say a twist of the bundle which will tend to untwist the yarn.

A traverse mechanism for controllingthe winding of the wirel with its load oi.' yarn on the spool 24 is conventionally indicated at 58. 'I'his traverse comprises a star wheel 59 which is engaged by a pin 60 projecting axially from-thespool 24. t

In the arrangement shown the cradle 6 is designed to give one twistl to the bundle of yarnA as it winds the twisted yarn once around the wire mandrel. This arrangement has been found to provide a satisfactory curl for the yarns with which experiments have been made. Obviously, however, any desired number of twists per wind may be obtained by a suitable gearing arrange-,

ment.

Various modifications of the apparatus shown I obviously may be made without departing from The wire mandrel 25 is fed in accurate timed relation to the speed of rotation of the cradles by means of a capstan drum positively driven from the shaft 1 and about which the 'wire is wrapped once or several times to maintain the required traction.

The cradle 5 unwinds the yarn from the wire and simultaneously untwists it.' As shown, the yarn passes from the point of unwinding tothe eccentric guide 35 and through the -tube 31 to exitat a point co-axial with the cradle and whence it passes through a traverse conventionally illustrated at 38 which lcan have one guidingl eye for each yarn, and thence to the spool 40 on which the several yarns are wound as is common practice in winding warp beams. The spool 43 is carried on the shaft 4| which is driven from the shaft 1 through belt gearing which Willvmaintain the desired tension on the yarn but will slip to prevent excessive tension. In the arrangement shown the tension of the belt 42 on the

pulleys

43 and 44 is such as to suitably drive the spool but permit slip when necessary to avoid excessive tension.` 'I'he traverse 38 isconventionally indicated as mounted on a pivot 45 about which it is given a rocking movement by a cam 46 on the shaft 1.

A fresh supply of yarn is twisted and wound upon the mandrel from which the curled and treated yarn has been removed.l For this purpose a charge of yarn is drawn from the spool 50 from -which it is guided to the winding cradle Suitable tension on the yarn is maintained by means of a brake 5| engaging a brake drum l to provide any desired twist. Obviously, it is a 52 secured to the shaft 53 on which the spool 50 is mounted. This form of support for the yarn to be curled is illustrative merely as obviously g the several separate yarns canbe Supported in any suitable manner, as b'y separate spools or spindles suitably arranged.

In order that the twisting of the yarn, if it be a bundle of yarns, may be confined to a reasonably short length a dividing pin 54 is positioned at a suitable distance from the end of the winding cradle 6. 'Ihe several yarns are separated by this pin into two groups and from the dividing pin they pass through a guide 55 and thence to the tubular element 55 which serves as the yarn guide of the cradle 6.

The yarn leaves the tube 55 through an eccentric guide 51 from which it is wrapped about the spirit of the invention.

The direction of twist shown is such as to untwist the yarn and this has been found preferable in curling most yarn, but obviously the direction of twist and the extent of twist may be varied to suit the particular yarn treated and the optimum conditions are readily ascertained by experiment. When analyzing the conditions of twist not only the twist of the yarn as a whole .but the effect on the twist of the strands making up the yarn should also be considered. In order to-obtain greater or less twist the yarn carrying spools can be mounted in rotatable cradles driven simple matter in view of the state of the art to devise gearing including for example planetary gearing for providing the necessary rotations and drive for the spools.

.If it is found desirable to adjust the speed of the drive of the wire automatically more accurately to accommodate the drive ofthe wire to the pitch of the previously wound yarn, a

. variable Speed drive may be substituted -for the capstan drive shown and the speed may be controlled in response to a feeler mechanism having a yarn guide closely adjacent the point of unwinding. Y

The wire may be made of any suitable material resistant to the action of moisture or any treating solution which may be used in the processing of the yarn, such for example as stainless steel.

wire at the If the wire is to be heated by an electric current during' the treatment or drying' of the yarn, the composition of the wire may be selected'with this purpose in mind. The wire should be sufiicientiy stiff to serve as a relatively rigid mandrel but as' flexible as is necessary for winding on the spools used.

The forgoing particular description lis illustrative merely and is not intended as defining the limits of the invention.

I claim:

1. 'I'he method of curling yarn which comprises winding the yarn under tension on an incompressible mandrel, treating the yarn at high temperature to set the curl and unwinding the yarn for use. f

2. The method o! curling yarn which comprises winding the yarn under tension on a flexible Wire. coiling the wire with the yarn thereon, and treating the yarn on the w'ire at a high temperature to set the curl.

3. The method of curling yarn which comis indicated, that' prises combining a number of yarns in a bundle, twisting and winding the bundle around an incompressible, substantially rigid core to form a curl in each yarn, the number of twists of the bundle being substantially equal to the number of turns about the core, and treating the yarn to set the curl.

4. The method of curling yarn which comprises twisting a number of yarns together, winding the twisted yarns under tension on an incompressible mandrel, treating vthe yarn to set the curl, unwinding the yarn from the mandrel and simultaneously untwisting the yarns.

5. The method of curling yarn which comprises twisting a number of yarns together, winding the twisted yarns on an incompressible mandrel,

steeping the yarn to set the curl, and unwinding the yarn from the mandrel and untwisting the same.

6. The method of curling yarn which comprises combining a number of yarns into a bundle,

twisting the bundle, winding the twisted bundle oi yarn under tension on'a wire, steeplng and drying the yarn while still wound on the wire and unwinding and untwisting the yarn.

7. The method of curling yarn which comprises combininga number of yarns into a bundle,

twisting the bundle of yarns and winding the same on an incompressible mandrel, treating the yarn while twisted and wound on the mandrel -3 further characterized by the direction of twist given to the yarn being opposite to the original direction o f twist of the yarn.

10. The method of curling yarn which cornprises combining a number of yarns into a bundle, twisting the bundle and winding the yarn on an incompressible mandrel under substantial ten-l sion, steeping, drying and unwinding the yarn from said mandrel and untwisting and separating the yarns. l

l1. The method of curling yarn which comprises combinlng a number of yarns into a bundle, twisting the bundle of yarns and winding the same on an incompressible mandrel, saturating the yarn with a solution of a resinuous material capable of providing a set in the yarn, removing the solvent and unwinding the yarn from the mandrel and untwisting the same.

ANDREW LANGSTAFF JOHNSTON. J n.