Production of bulky and stretchable knitted cord
United States Patent 1191 Tsunekawa 1 Apr. 22, 1975 1 PRODUCTION OF BULKY AND STRETCHABLE KNITTED CORD 22 Filed: Mar. 22. 1973 211 App]. No.: 344,037  
 [30] Foreign Application Priority Data Mar. 28. 1972 Japan 47-31073 [52] US. Cl. 66/146; 66/152; 66/169 [51] Int. Cl.. D04b 9/100; D04b 15/44; D04b 15/88 [58] Field of Search 66/8. 169. 9 A. 125 R, 66/146.149,150. 151.152.153.147  
 [56] References Cited UNITED STATES PATENTS 1.518.378 2/1923 Adams 66/8 UX 1.947.958 2/1934 Wclch ct al.. 66/146 2.078.050 4/1937 Beniston 66/146 X 2.213.720 9/1940 Seim 66/1 R 2.264.069 1 H1944 Cloutier 66/146 X 2.656.690 10/1953 Buxbaum et a1. 66/8 2.856.764 10/1958 Carden 1 66/146 3.442.100 3/1967 Manger et a1. 66/153 3.448.594 6/1969 Macon... 66/147 3.51 1.062 3/1967 Nogucs 66/81 3.635.052 1/1972 Monncy 66/146 Primary E.\&#39;aminer--W. C. Reynolds Assistant ExuminerAndrew M. Falik [57] ABSTRACT At least one strand of yarn is supplied under tension to the knitting needles of a circular knitting machine and continuously knitted into a tubular knitted cord. which is led under tension away from the needles. these actions being carried out as at least one of the tensions in the supplied yarn and in the cord is abruptly periodically varied or reduced for an instant. This variation in tension can be accomplished by periodically varying either the tension in supplying the yarn and/or the tension with which the cord is drawn away from the needles. The cord is formed with nodules at intervals along its length. the nodules being made of relatively large yarn loops.  
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 PRODUCTION OF BULKY AND STRETCHABLE KNITTED CORD BACKGROUND OF THE INVENTION This invention relates generally to knitting and knitted yarns and more particularly&#39; a method and device for producing bulky, hollow and stretchable knitted cord.  
  Heretofore. the so-called Lillian braid has been known as one type of braid. of which an example is disclosed in U.S. Pat. No. 2.656.690 dated Oct. 27. I953 to M. Buxbaum Et Al: knitting device.&#34; This braid is made into a form of braided cord by knitting with maximum knit density by means of a conical-needlecylinder. the circular knitting machine having a plurality of knitting needles. with the object of eliminating stretch and shrinkage or elasticity as much as possible and without rendering the fabric into a hollow structure.  
 SUMMARY OF THE INVENTION It is an object of this invention to provide a method and device for producing bulky. hollow and stretchable knitted cord of high elasticity wherein loops are made to form knots or nodules of a suitable number and dimension by adjusting the knit density. thereby to fabricate knitting yarns of light weight per unit volume having various structural features and which are suitable as knitting yarns and weaving yarns.  
  Yarns thus produced in accordance with this invention have aesthetically pleasing appearance and texture. resilience. flexibility. soft and clinging feel. porous texture due to loops. and high thermal insulative property.  
  According to this invention in one aspect thereof. there is provided a method of producing yarns as described above which comprises forming a tubular braid or cord by means of a plurality of knitting needles of a circular knitting machine supplied with at least one strand of yarn. at least the tension of the yarn thus supplied or the tension of the cord led away from the needles being periodically reduced or varied. abruptly, for an instant, or both tensions being periodically reduced.  
  According to this invention in another aspect thereof. there is provided an apparatus for producing bulky. hollow and stretchable knitted yarn. comprising: a circular knitting machine having means for supplying under tension at least one strand of yarn. a circular knitting mechanism including a plurality of knitting needles and operating to knit said yarn into a tublular knitted braid or cord. and means for conducting under tension the cord thus knitted away from the needles; first and second tension-varying or reducing means optionally operable to vary periodically, abruptly. for an instant the tension in the yarn and in the knitted braid.  
  The nature. utility.&#39;and further features of this invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings. in which like parts are designated by like reference numerals and characters.  
 BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is a side elevation showing the essential parts of an exemplary embodiment of a priorart circular knitting machine suitable for use in practicing of this invention;  
  FIG. 2 is a vertical section taken along the plane indicated by line ll-lI in FIG. 1 as viewed in the arrow direction;  
  FIG. 3 is a horizontal section taken along the plane indicated by line lIIIII in FIG. 1 as viewed in the arrow direction;  
  FIG. 4A is a side elevation showing one example of a device for adjusting the tension of the yarn being supplied:  
 FIG. 4B is a side elevation showing a known adjusting device. similar to the device shown in FIG. 4A;  
  FIG. 5 is a side elevation showing a modified example of a device for adjusting the tension of the cord knitted yarn;  
  FIG. 6 is a front elevation orthogonal to the side elevation of FIG. 5;  
  FIG. 7 is an enlarged. fragmentary view showing a plain knitted structure;  
  FIG. 8 is an enlarged view in the longitudinal direction of a part of a bulky. hollow knitting yarn braided in accordance with this invention:  
  FIG. 9 is a fragmentary perspective view of the knitting yarn shown in FIG. 8;  
  FIG. 10 is a view similar to FIG. 8. showing an example of modification of the knitted yarn; and  
 FIG. 11. is a side view of the modified bulky yarn.  
 DETAILED DESCRIPTION Referring first to FIG. I, the knitting mechanism of a circular knitting machine illustrated therein. and generally designated by reference character N for producing bulky. hollow knitting yarn. has a stationary base plate 3 on which the principal operational parts of the knitting mechanism are supported. A pulley 5 is rotatably supported on the base plate 3 to be rotated continuously about a vertical axis by power transmitted from motive power means (not shown) through an endless belt 4. This pulley 5 is supported through a support part 6 by the base plate 3.  
  A rotary cylinder 7 is rigidly and coaxially fixed to the pulley 5 and is unitarily rotatable therewith. A cylindrical cam 8 fitted in the rotary cylinder 7 comprises an upper section 8a and a lower section 8b. which are fixed to the rotary cylinder 7 by screws 9a and 9b as shown in FIG. 2. These screws 9a and 9b pass through vertical slots 7a and 7!; formed in the rotary cylinder 7. Accordingly. the upper and lower cam sections 8a and 8b can be adjusted in their vertical positions by loosening the screws 9a and 9b. adjustably moving the sections 8a and 8b vertically, and retightening the screws 9a and 9b.  
  Between these upper and lower cam sections 8a and 812. there is formed a guide cam groove 10, in which are slidably fitted butts 11a of four latch needles 11. These latch needles have respective hooks Ilb and latches llc at their upper ends in the conventional manner and are held and guided vertically in the following manner. The stems of these latch needles 11 are slidably inserted through vertical guide grooves 12a formed in a latch needle supporting member 12 as shown in FIGS. I and 3.  
  This latch needle supporting member 12 is secured to and held on the stationary base plate 3 indirectly by a member 13 extending vertically within the cam 8 as shown in FIG. 2. Accordingly. even when the rotary cylinder 7 and the cylindrical cam 8 rotate about their axis, the supporting member 12 and the latch needles supported thereon do not rotate. and the cam grooves I of the cylindrical cam 8 impart a cam action to the butts Ila sliding therein. whereby the four latch needles II successively undergo repeated up-and-down reciprocation thereby to carry out the knitting of a yarn Y supplied to the knitting mechanism as indicated in FIG. 1.  
  The yarn Y is continuously supplied through a hole 140 in a yarn guide 14 supported to rotate together with the aforementioned pulley to the knitting mechanism described above. where the yarn Y is continuously knitted by the latch needles 11 into a knitted yarn or cord B of tubular form. which then passes through the interior hollow space of the cylindrical cam 8 and through a passageway (not shown) in the interior of the base plate 3 and is then taken out downward as indicated in FIG. 1.  
  Prior to its being supplied to the circular knitting mechanism N shown in FIG. I, the yarn Y is unwound from a yarn supplying bobbin 15 as shown in FIG. 4A and then passed through a supply yarn tension adjusting device T, as shown in FIG. 4A. for example. This device T, has a central bolt 17 having an enlargeddiameter shank with a hole 16 for yarn passage. a bolt head 18 at the lower end. and a nut 19 in screw engagement with the threaded upper end.  
  Around the enlarged-diameter shank of the belt 17, there are fitted two yarn-clamping plates 20 and 21. The upper yarn-clamping plate 20 is continually urged downward toward the lower yarn-clamping plate 21 by the elastic force of a coil spring 22 and is normally in contact with the lower yarn-clamping plate. Accordingly. as the yarn Y passes through this tension adjusting device T, it is clamped between the two clamping plates 20 and 21, whereby a yarn supply tension is imparted to the span of the yarn Y between the device T, and the circular knitting mechanism N. i  
  This supply tension is periodically variable by a rotating member 24 driven in rotation about a vertical axis by a motor M and having a laterally extending arm 24a adapted to enter at its outer extremity between the upper and lower clamping plates 20 and 21. When this arm 24a periodically forces itself between the two clamping plates, the upper plate 20 is lifted against the force of the spring 22 and separates from the lower plate 21 as shown in FIG. 4A. Consequently, the yarn tension is periodically and abruptly reduced for an instant. Thus. the yarn supply with the rotation of the rotating member 24.  
  In a known yarn supply tension adjusting device T illustrated in FIG. 4B, the two yarn-clamping plates 20 and 21 are continually in the clamping state. whereby a continually constant yarn supply tension is obtained.  
  As indicated in FIG. I. the bulky hollow yarn B is taken out from the knitting mechanism N by a positive take-up roller device T comprising, essentially. a pair of upper and lower rollers 27 and 28. The yarn knitted by the inventive machine is bulky because the knit cord itself is hollow. It will be understood that a hollow cord is necessarily more bulky than a single yarn. Moreover, the knit cord according to the present invention naturally affords bulkiness since it is formed with nodules at intervals. as will be explained in more detail. Of the rollers 27, 28, the lower roller 28 is fixed and has a shaft 28a which is supported to move only in rotation,  
 while the upper roller 27 is supported on a shaft 27a, which is rotatably supported by support parts 31 of truncated Vee shaped of elastic support members se cured to the lower side of the base plate 3 by way of brackets 29.  
  In this state. the cylindrical peripheral surface of the upper roller 27 is urged by the force of gravity toward the cylindrical peripheral surface of the lower roller 28. Accordingly. when the roller 27 is driven in the arrow direction, the bulky hollow yarn B is caused to travel downward as it is clamped between the two rollers, whereby the tension is reduced in the braided yarn B, as explained earlier.  
  In an example T, of the positive take-up roller device, as illustrated in FIGS. 5 and 6, and constituting a modification of FIG. 1, the braided yarn B is passed between upper and lower rollers 32 and 33. In this arrangement also the lower roller 33 is stationary, while the upper roller 32 is urged by the force of gravity toward the lower roller 33. At one part of the cylindrical surface of the lower roller 33, there are secured spacing pads 34 made of an elastic material. Accordingly, when the pads 34 arrive at their positions between the two rollers as indicated in FIGS. 5 and 6 as the roller 33 rotates, these pads lift the upper roller 32 relative to the lower roller 33, whereby a spacing is formed between the two rollers. permitting the yarn B to pass freely therethrough. Consequently. the tension in the yarn B is reduced to zero. but in the next instant. the spacing pads 34 rotate past the indicated positions, whereby the surface of the upper roller 32 is lowered again. to approach the surface of the lower roller 33. The yarn B is thereby clamped again between these rollers. and tension is again affected.  
  The knitting mechanism and related mechanisms of the above described organization according to the invention operates in the following manner. The yarn Y supplied from the yarn supplying bobbin 15. through the tension adjusting device T,, and toward the knitting mechanism N. is caused by the revolving yarn guide 14 to be fed as it revolves around the latch needles II. Since the latch needles 1] are moving successively up and down at the same time as a result of the action of the cam 8, they operate in the known manner to knit a hollow. knitted yarn B of Lillian form. as defined earlier. having a plain knit texture.  
  In this case, when the supply yarn tension adjusting device T, shown in FIG. 4A is set to function in a constant manner by not operating the rotating member 24 driven by the motor M. or the device T shown in FIG. 4B is used, thereby to maintain constant the tension in the yarn Y, a hollow yarn having a plain knit texture is obtained as indicated in FIG. 7.  
  In the case where the rotating member 24 of the device T, is rotated, the upper clamping plate 20 is periodically raised by the arm 24a of the rotating member 24, whereby the supply yarn tension is periodically reduced. When the tension in the yarn Y is reduced in this manner, the knitting loop formed by each needle 11 becomes larger than a loop formed under normal conditions. As a result. as indicated 11 FIGS. 8 and 9, relatively large loops Y! are formed in the resulting bulky, hollow yarn B at certain intervals along the yarn.  
  FIG. 10 illustrates an example of a bulky. hollow yarn wherein two large loops Y! in opposed positions and two small loops Ys in opposed positions are formed. This knit. shape can be obtained by suitable timing of the variation of the supply yarn tension and the movements of the needles 11, the loops YI being formed by smallergauge needles and the loops Ys by larger-gauge needles.  
 Bulky. hollow yarns B of the configurations described above and illustrated by H68. 8. 9 and 10 can be prov duced also by effecting a variation in the tension in the braid knit yarn by means of the take-up roller device T3.  
  Furthermore, by combining the variation in the tension on the supply yarn side and that on the knitted yarn side. it is possible to produce bulky. hollow yarns of various patterns wherein large loops and small loops are mixed in complicated arrangements.  
  An example of a knitted yarn is illustrated in FIG. ll wherein bulky yarn parts made up of large loops Y1 and bulky yarn parts made up of small loops Ys are alternately disposed along the yarn and respectively occupy certain lengths of the yarn. This configuration can be obtained by causing the period of the yarn tension variation on the supply yarn side or the drawing out side to be considerably long with respect to all parts.  
  In order to indicate more fully the nature and utility of this invention, the following specific examples of practice are set forth constituting preferred embodiments of this invention and results. it being understood that these examples are presented as being illustrative only and that theyare not intended to limit the scope of the invention.  
 EXAMPLE 1.  
 ply package and passed through a supplied yarn tension adjusting or reducing device under a tension in a range within which knitting was possible and could be readily accomplished and in a manner such as to suppress as much as possible fluctuations in the supplied yarn tension during the knitting.  
  The yarn thus adjusted in tension was supplied to the knitting needles. by which the yarn was knitted into a linear shape ofa row of four loops in hollow cylindrical formation, the latches being opened and closed by the already formed loops as new loops were successively formed. By means of positive take-up rollers, a tension comprising the knit material tension and the take-up tension in a well-balanced state was applied to the already knit loops thereby to pull the same. and continuous knitting was carried out with the knitting action maintained in a smooth state, whereby a bulky, hollow knitted braid was produced.  
  As a result. from the 50 Tex woolen single yarn of a strength of 184 grams (g.) and an elongation of 11.1 percent used as the starting yarn. a bulky braided yarn of 526.3 Tex of a strength of l K 460 g. an elongation of 20.9 percent, and an average bulkiness of 12.3 cm/g was obtained.  
 EXAMPLE 2.  
  Under the same knitting conditions in Example 1. 29.5 Tex two-ply yarn was knitted into a bulky braided cotton yarn of hollow tubular form according ,to this invention.  
  As a result. from this two-ply cotton yarn of a strength of l K. 110 g. and an elongation of 5.3 percent used as the starting yarn. a bulky braided yarn of 720.2  
 Tex. a strength of 6 K. 900 g.. an elongation of 21.2 percent. and an average bulkiness of 7.3 cm/ g. was obtained.  
 EXAMPLE 3.  
  By means of a cylindrical-type. circular knitting machine having a needle cylinder of O.l-inch diameter. a total of four needles. of which two were latch needles for knitting needle number 5 gauge and two were latch needles for 8 gauge (the needle organization being 1 :1 and a yarn feeding aperture at one position. a 29.528 Tex two ply cotton yarn was knitted into a bulky braided yarn of tubular form.  
  The purpose of using together latch needles for 5- inch gauge and for 8-inch gauge in this method was to make large and small loops in the yarn. thereby to form concavities and convexities on the lateral surface of the braided yarn whereby. with the same starting material. a bulky braided yarn having much greater variation in bulkiness can be obtained than a bulky yarn of uniform loops knitted by the same knitting needles. and having large and small loops of aesthetically pleasing appearance. texture and resilience.  
  As a result. from the 29.527 Tex. two-ply cotton yarn ofa strength of l K l 10 g. and an elongation of 5.3 percent used as the starting yarn. a bulky braided yarn of a count of cotton yarn of 703 Tex. a strength of 6 K 500 g.. an elongation of 22.5 percent. and an average bulkiness of 8.8 cm lg. was obtained.  
  A bulky. hollow braided yarn produced by this procedure is illustrated in FIG. 10.  
 EXAMPLE 4.  
  In a cylindrical-type. circular knitting machine having a device for varying the yarn supply speed and/or the supply yarn tension. a needle cylinder of 01-inch diameter. four latch needles for 8-inch gauge. and a yarn feeding aperture at one position. a cotton-fiber No. 20 two-folded yarn was pulled out from a supply package and supplied to the knitting needles with settings of the supply yarn tension and the take-up tension selected to facilitate knitting. at a knitting speed of 4 meters/min. as the yarn supplying speed was caused to fluctuate continuously and intermittently with a ratio of 1.00 1.1 l. at intervals of 0.65 second. thereby to knit a bulky braided yarn of tubular form.  
  As a result. from the 29.527 Tex, two-ply cotton yarn ofa strength of l K.l 10 g. and an elongation 0f5.3 percent used as the starting yarn. a bulky. braided. knotted or. nodular yarn. as shown in FIG. 11. of a count of 798.02 Tex. a strength of 6.550 Kg.. an elongation of 24.7 percent. an average bulkiness of 10.1 cm&#34;/g.. a nodule density of 23 nodules per meter of yarn length. and an apparent ratio of the diameters of the nodule parts and the parts without nodules of 1.3 was produced.  
 EXAMPLE 5.  
  In a cylindrical-type. circular knitting machine having a takeup tension variations device as illustrated in FlGS. 5 and 6, a needle cylinder of 0.1-inch diameter, four latch needles for 25-inch gauge. and a yarn feeding aperture at one position and having the effect ofa wave holder without a sinker. 29.527 Tex two-ply cotton yarn was pulled out from a supply package and supplied to the knitting needles with settings of the supply yarn tension and the take-up tension selected to facilitate knitting. at a knitting speed of 2.36 meters/min. as the take-up tension was caused to fluctuate with a ratio of l.0() 2.81. and the tension was caused to fluctuate to zero continuously and intermittently. at intervals of 0.5 second thereby to knit a bulky braid yarn of tubular form.  
  As a result. from the 29.527 Tex. two-ply cotton yarn of a strength of L1 l Kg and an elongation of 5.3 percent used as the starting yarn. a bulky. braided. knotted or nodular yarn of a count of 881.40 Tex. a strength of 4.100 Kg. an elongation of 26.5 percent. an average bulkiness of 8.3 cm/g.. a nodule density of 51 nodules per meter of yarn length. and an apparent ratio of the diameters of the nodule parts and the parts without nodules of 1.43 was produced.  
 I claim:  
  1. An apparatus for producing bulky. hollow knitted cord comprising: a circular knitting machine having means for supplying under a tension at least one strand of yarn. a circular knitting mechanism including a plurality of knitting needles and operating to knit the yarn into a tubular knitted cord and means for conducting the latter away from said needles under tension; a first tension-varying device optionally operable to vary periodically the tension in the yarn being supplied; and a second tension-varying device optionally operable to vary periodically the tension in the cord being conducted away from said needles. wherein said second tension-varying device includes a lower driving roller having spacing members forming therebetween a path for conducting the cord. and an upper driven roller resting on said lower roller so as to be movable away therefrom and operative to clamp the cord between said rollers to apply a tension to the cord. said upper roller being moved away from said lower roller and caused to rest on said members to decrease the tension of the cord when said members are brought between said rollers as said lower roller rotates.  
  2. In a method of producing a bulky and stretchable knitted cord. comprising the steps of supplying at least one strand of yarn under tension to a plurality of knitting needles ofa circular knitting machine. knitting the yarn into a tubular knitted cord by means of the needles. and conducting the cord away from the needles under tension: the improvement comprising the step of reducing the said tensions abruptly, for an instant. in a periodic manner. both in the yarn being supplied and in the cord being conducted away. in such a timed relationship with said knitting step that the knit cord is formed with nodules at intervals along its length, the nodules being made up of relatively large yarn loops.  
  3. In an apparatus for producing a bulky and stretchable knitted cord, comprising means for supplying under tension at least one strand of yarn. a circular knitting mechanism including a plurality of knitting needles and operating to knit the supplied yarn into a tubular knitted cord, and means for conducting the latter away from said needles under tension: the improvement comprising first tension reducing means acting on the yarn being supplied. second tension reducing means acting on the cord being conducted away from said needles. and means for operating said tension reducing means in such a manner that the respective tensions are reduced abruptly. for an instant. in a periodic manner. in such a timed relationship with the operation of said needles that the knitted cord is formed with nodules at intervals along its length. the nodules being made up of relatively large yarn loops.  
  4. The apparatus as defined in claim 3, wherein said first tension reducing means includes a pair of clamping plates for resiliently clamping therebetween the yarn being supplied. and a member periodically entering between said plates to separate them so as to reduce the yarn tension.