US2972798A - Crimping - Google Patents

Description

Feb. 28, 1961 R. K, STANLEY E-r AL 2,972,798

CRIMPING Filed Jan. 25, 1957 1 O /8 25 2 9 i ihr-25 25 /7 .ffl /7 /7 gffg# 5 milf 36/6 576 36 V 9 3435 gel @I2 6 6 I v /2 'U1 2C n" 42 36'6 gl: /3 3%/3 l' 26 la?" qu 6 f; 23 /6 1|; -l 212 1|@ 24 4'- V 4 4 22# 2z* 8 l 28 e' 8 '1| 7 I "23 ll 3 INVENTORS ROBERT l( STANLEY IRA 6 CHWA R TZ ATrRNEY acity and other desirable characteristics.

United States Patent CRIMPING Filed Jan. 2s, 1951, ser. No. 635,845 s claims. (c1. zs-rz) This invention relates to crimping of filamentary articles of polymeric organic composition, usually in the form of continuous multifilament, hereinafter referred to simply as textile strands, for manufacture into fabrics of woven, knit, or other construction useful for textile or industrial applications.

Fabrics made up of rectilinear smooth-surfaced textile strands, especially those composed of material having hydrophobic characteristics, are unpleasantly slick to the touch, usually highly translucent, and lacking in bulk and covering power. Although these defects can be alleviated by conversion of the filaments into a continuoustructure of staple fibers or by other physical or chemical treatment, subjection of the strand to a crimping operation precludes necessity for the complex and time-consuming steps of staple formation and gives products exhibiting high ten- As here (and usually) understood, crimping denotes the more or less permanent deviation of a strand, whether filament by filament or as a group of filaments, as from the substantial rectilinearity of its customary as-produced configuration. The deviation or crimp may be either periodic or aperiodic, depending upon the method employed, as is well known in the art. It generally is accepted that synthetic filaments of almost any composition can be crimped somehow or other, although for obvious reasons the various thermoplastic compositions have proved especially ameuable to crimping. Depending upon the process employed, the resulting crimp configuration may exhibit undesirable regularity or extreme irregularity, the crimp frequency may be insufficient, or the crimp may be characterized by annoying residual torque or helical liveiiness in the strand; barr and other irregularities may result in fabric s composed.

A primary object of the present invention is improvement in characteristics of twist-crimped textile strands and of fabrics composed of them. An object is certain compound or multiplie crimping of textile strands to overcome undesirably regular crimp characteristics. A particular object is elimination of residual torque from strands having a helical crimp. Other objects of this invention, together with means and methods for attaining the various objects, will be apparent from the following description and the accompanying diagrams.

Fig. 1 is a schematic or block diagram indicating practice of the present invention as an adjunct to existing practice. Fig. 2A is a front elevation (partially cut away), Fig. 2B a side elevation, and Fig. 2C a horizontal section (taken at 2C-2C of Fig. 2B) of a form of apparatus for practicing the present invention. Fig. 3A is a side elevation of a multifilament textile strand before crimping; Fig. 3B is a view of this strand after performance of a first crimping operation upon it; and Fig. 3C is a like vicw of the same strand after further crimping according to this invention.

In general, the objects of the present invention are accomplished in a textile strand by supermposing an irregular crimp configuration upon an existing crimp con- 21,972,798 Patented Feb. 28, 1981 guration characterized by undesirable regularity of direction, frequency, or the like. The invention contemplates performance of this by continuously feeding a regularly crimped textile strand into a confining chamber, thereby modifying the crimp configuration of the strand, and withdrawing the strand with modified crimp configuration from the confining chamber, especially without necessity for externally appliedv heat. Particularly comprehended in the filamentary materials upon which this process is highly effective are textile strands that exhibit a helical liveliness, inasmuch as the present crimping operation is effective -to inhibit that livelness while also imparting additonal desired characteristics to the strand.

Fig. 1 shows (diagrammatically) uncrimper strand 10 entering first crimper 1 to emerge as crimped strand 20; this crimped strand then enters second crimper 2, in which further crimping is accomplished according to the present invention, strand 30 being the resultant.

Figs. 2A, 2B, and 2C show in front elevation, side elevation, and sectional plan, respectively, one form of stutter-crimper" capable of satisfying the requirements for the second crimper of Fig. 1. This crimper, which is of a general type well known in the art, has as its principal supporting parts base or bottom plate 11 and top plate 12 extending horizontally, front plate or facade 13 extending vertically from the bottom plate to and above the top plate, and back plate 23 joining the bottom and top plates at the rear. Also prominent are pair 0f stuffer rolls 4, 4', located side by side in front of the facade between the two horizontal plates, and crimping tube 5 extending from above the nip of the stuffer rolls to a level well above the top of the facade. Four wingnuts 6, threaded on studs 36 extending from the facade, retain washers 16 against the front of the tube to hold it in place against the front of the facade, with the saddleshaped lower end of the tube (shown in broken lines) closely approaching the roll nip.

The top of the tube is closed by cover 15 pivotally affixed by depending ear 18 to pin 29 on the exterior wall of the tube, and the cover is urged downwardly "ice against the top of the tube by springs 25, 25 affixed at 17' and at the upper end to the cover by pins 19, 19'. located near the top of the tube opposite the front of the cover. Drive motor 9 is mounted on the top plate, and shaft 34 extends rearward from the motor and through journal 35 upstanding from the back plate. The motor shaft carries drive pulley 32, about which drive belt 26 passes. The drive belt also passes about pulley 24 on shaft 22, which extends rearward from feed roll 4 affixed to the shaft. As shown in Fig. 2C, gear 28 on shaft 22 meshes with like gear 28' on shaft 22', which extends rearward from feed roll 4' mounted on it. The strand itself is omitted from this latter view for simplicity of the. representation.

Initially crimped strand 20 passes upward from the source of supply (not shown) located below the illustrated apparatus, passes over feed block 7 secured to the facade by screw 38 and under overlying clip 8 attached by screw 37 into the side of the block, both located just below the roll nip to form an entering or infeeding guide, and the strand then passes through the nip of the counterrotating stufier rolls and into the close-fitting lower end of the crimping tube. Part of the tube is cut away in Fig. 2A to reveal the accumulation of yarn stuffed up through the bore of the tube. The cover provides back pressure effective to impede exit of crimped strand 30 from the tube. Thus, the strand (filling the tube) bends back and forth and from side to side as it is stuffed into the bottom end of the tube, these various deviations from the original configuration of the strand being emphasized under the applied back pressure to the extent of becoming a relatively permanent crimp.

The actual crimping occurs essentially as is customary in this general type of crimper, other forms of which are disclosed in the following U.S. patents, inter alia: 2,311,174 -to I. V. Hitt; 2,715,309 to N. Rosenstein et al.; 2,734,228 to W. D. Hay; and in U.S. patent application, Serial No. 624,613, filed November 27, 1956, by Ralph W. List and Ira Schwartz, in which passage of the crimped yarn accumulation through an open-ended crimping tube is impeded by a unidirectionally rotatable gear or similar element intercepting the bore of the tube at least partially.

Any of the following well-known crimping devices and l procedures may be employed to impart the initial crimp, i.e., to convert simple multiflament strand 10 to singly crimped multiflament strand 20: the devices and procedures illustrated in U.S. Patents 2,111,209 and 2,216,810 to H. Dreyfus; 2,089,198, 2,089,199, 2,089,200 and 2,- 111,211 to D. Finlayson et al.; 2,089,239 to W. Whitehead; 2,463,619 to A. Kunzle; and 2,463,620 and 2,655,- 781 to G. Heberle'in. The immediate products of these crimping techniques and apparatus exhibit undesirable recurrence or regularity of crimp, which can be alleviated according to the present invention while retaining many of the benefits of that initial crimp or even enhancing them and endowing the strand with further desirable characteristics.

An especially undesirable feature of twist-crimped strands is the residual torque or helical liveliness exhibited by them as a result of the twisting (or false-twisting) to which they were subjected, usually accompanied by setting and followed by purported elimination of the twist. The unbalance of such lively strands conventionally is balanced by plying (strands of opposite twists) or by other well-known techniques to prevent unwanted distortion of garments and other articles so composed. The present invention is especially adapted to elimination or minimization of that liveliness, usually at the same time imparting a closer but more nearly random crimp to the component filaments, two results that in many respects appear contrary and either of which was unpredictable.

Fig 3A represents the lateral appearance of strand 10 of continuous filaments, the filaments lying in substantial rectilinear alignment, as produced by any of the many well-known methods. Fig. 3B represents corresponding strand 20 having an initial crimp, preferably imparted to it by one of the regular false twisting methods; while it has become shorter than the uncrimped strand, no attempt is made in the drawing to suggest the change in length imparted by the crimping. Noticeable are both a periodic or recurrent undulation of the strand as a hole and a shorter wavy crimp in the individual filaments, this configuration being indicative of the previously mentioned helical liveliness.

Fig. 3C shows strand 30, which corresponds to previous strand 20 after a second crimping, as indicated above. The outline is more uniform, the crimp spacing closer but less regular, and the interlament spacing greater, with the result that this strand is bulkier or loftier. Little or no trace remains of the phased multilament undulation visible in strand 20, and the helical liveliness is likewise absent. In general, twist-crimped strands subsequently stuffer-crimped according to this invention exhibit a greater degree of recovery to the crimped length after removal of extensional force than characterized the initially twist-crimped strands (or, for that matter, conventional stutfer-crimped specimens); this is the more surprising inasmuch as the high crimp-elasticity of twist-crimped (i.e., strand-extensibility without actual stretching of the component filaments) is greatly reduced as expected, by the stuffing step.

These striking transformations in the strand are carried over into fabric composed thereof, to endow it with characteristics considerably different from those of fabrics composed of regular twist-crimped strands (inherently unbalanced) or of the uncrimped multifilament (notably slick and translucent). In loftiness and covering power such fabric is fully the equivalent of or superior to that produced from continuous-filament strands subjected to the complex and expensive procedure of hot stuffer-crimping, one feature of the present invention being the freedom of the prescribed stuffer-crimping step from the necessity of applying heat from the outside; of course, heat may be applied if desired, although it actually may be deleterious to the initial or preceding crimp. The many procedural advantages and product-wise benefits of this invention will become fully apparent to those undertaking to practice it in its entirety.

The claimed invention:

1. Process of treating a twist-crimped textile strand of continuous filaments to alter its configuration of crimp, increase its crimp-recovery, and substantially eliminate its helical liveliness, comprising subjecting it on the run to a stutfer-crimping operation.

2. Crimped strand produced by the process of claim 1 and exhibiting, as compared with the strand before being so treated, increased crimp-recovery, substantial lack of helical liveliness, and decreased crimp-elasticity.

3. Process of treating a textile strand of continuous filaments comprising the steps of twist-crimping such a strand to give it a regular helical crimp, and crimping said twist-crimped strand to modify the regular helical crimp by superimposing thereon a haphazard crimp with a random distribution of crimp angle.

References Cited in the file of this patent UNITED STATES PATENTS 2,647,285 Pfau Aug. 4, 1953 2,715,309 Rosenstein et al Aug. 16, 1955 2,865,080 Hentschel Dec. 23, 1958 FOREIGN PATENTS 595,634 Great Britain Dec. 1l, 1947 682,263 Great Britain Nov. 5, 1952 OTHER REFERENCES Du Pont Technical Information Bulletin N-56, page 23, February 1956, E. I. Du Pont De Nemours & Co., Wilmington, Del. (Copy in Division 21, U.S. Patent Office.)

R. W. Moncrief, Artificial Fibers, page 409; John Wiley & Sons, Inc.; New York, N.Y.; 1954. (Copy in Division 21, U.S. Patent Omce.)

UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,972,798 February 28, 1961 Robert K. Stanley et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below'.

Column l, line 52, for "multiplie" read multiple column 2, line l5, for "uncrmper" read uncrmped column 3, line 49, for "false twisting" read false-twisting line 54, for "hole" read whole column 4, line 9,

Signed and sealed this 18th day of July 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Pate-nts UNITED STATES PATENT oEEIeE CERTIFICATION OF CORRECTION Patent No., 2,972,798 February 28, l9l

Robert K. Stanley et al.

It is hereby certified that error appears n the above numbered patent requiring Correction and that the said Letters Patent should read as Corrected below'.

Column l, line 52, for "multiplie" read multiple column 2, line l5, for "uncrmper" read uncrmped column 3, line 49, for "false twisting" read false-twisting line 54, for "hole" read whole column 4, line 9, after "twist-crimped insert strands signed and sealed this 18th day of July- 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

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