Method of and apparatus for producing partially bulked yarn
United States Patent [191 Kawasaki et al.  
 Filed:  
 Appl. No.: 427,491  
 METHOD OF AND APPARATUS FOR PRODUCING PARTIALLY BULKED YARN Inventors: Kentaro Kawasaki; Keizo Takizawa,  
 both of Osaka, Japan Assignee: Chori Company Limited, Osaka-shi,  
 .lapan Dec. 26, 1973 Field of Search 57/1 R, 34 R, 34 HS, 34 AT, 57/91,106,156,157 R, 157 TS, 157 MS Jacobs ct al.  
 [ Apr. 1, 1975 Neff 57/91 X Horvath 57/157 TS X Stoller ,1. 57/106 X Schroeder 57/91 X Sequin 57/91 X Nagel et a1 57/34 HS Braker 57/157 TS X Shah 57/34 AT Primary Examiner-Donald E. Watkins Attorney, Agent, or FirmWhittemore, Hulbert &amp;  
 &#39; Belknap Foreign Application Priority Data Dec. 28, 1972 Japan 48-2550 US. Cl. 57/34 HS, 57/91, 57/157 TS Int. Cl. D02g 3/34 ABSTRACT A method of and an apparatus for producing partially bulked yarn from a twisting heat setting untwisting type process by alternately imparting uniform tension and non-uniform tension to more than two pieces of filaments, characterized in that said filaments are additionally subjected to pre-twisting of after-twisting.  
 3 Claims, 8 Drawing Figures FATENTEUAPR H975 3,874,153  
 sum 1 n5 2 FIG &#39;I FIG, 2  
  I METHOD OF AND APPARATUS FOR PRODUCING PARTIALLY BULKED YARN BACKGROUND OF THE INVENTION The present invention relates to a method of and an apparatus for producing specific bulked yarn.  
  It is known to produce bulked yarn with varied bulkiness along its length by feeding more than two pieces of filaments to a single twisting spindle and then passing them through a series comprising steps of twisting, heat setting and untwisting while changing the tension between the filaments by suitable means capable of ad justing the feed tension.  
  In methods presently used, two (or more) pieces of filaments are first fed to the same twisting spindle of a false twister and then passed, while in a doubled state, through a series of steps comprising twisting, heat setting and untwisting. In the course of this process there is provided between the feed section and the suitable means for intermittently changing the tension between the two filaments so as to provide the respective filaments with different feed conditions. If the two filaments, differing in tension from each other, are supplied to the twisting spindle, the filament with the smaller tension is given sufficient twist while the filament with greater tension is afforded insufficient twist. As a result, the former receives sufficient crimping in the succeeding crimping step and is bulked, while the latter is provided insufficient crimping and little or no bulk. As these operations are performed intermittently, there is formed a partially bulked yarn, or a yarn with its bulkiness varied regularly along its length, such as shown in FIG. 1.  
  Such partially crimped yarn is generally lower in retractability and torque than the usual crimped yarn which has been prepared from an ordinary twisting heat setting untwisting process and which is uniformly crimped along its entire length.  
  The present invention removes such defects of the partially crimped yarn.  
 BRIEF SUMMARY OF THE INVENTION The present invention envisages an improved bulked yarn having alternate bulked portions and non-bulked portions, with the difference between the bulked and non-bulked portions being made more conspicuous. so that this yarn can be used in a fabric, with resultant excellent creping effect.  
  More particularly, the present invention proposes a method of obtaining an improved partially bulked yarn from a twisting heat setting untwisting process by imparting uniform tension and non-uniform tension to more than two pieces of filaments and further adding an extra twisting step, thereby making more conspicuous the difference between the bulked and the nonbulked portions. The extra twisting step may be incorporated before the partial bulking work (that is, it may be incorporated as a pro-twisting step), or after the partial bulking has been completed (that is, it may be adapted as an after-twisting&#34; step).  
  The present invention also features means for changing the tension of the filaments, said means comprising a roller provided around its periphery with a yarn guiding groove and designed to be capable of optionally controlling the working period, whereby it is possible to form the desired bulked and non-bulked portions at high speed.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a filament having the bulked and non-bulked portions;  
  FIG. 2 is a diagram showing the change of twist and the bulked portions of a partially bulked yarn;  
  FIG. 3 is a schematic drawing of an apparatus of the present invention;  
  FIGS. 4, 5 and 6 are schematic drawings showing the change of filament tension;  
  FIG. 7 is a perspective view of a grooved roller with a filament fitted in a groove 17 therein; and  
 FIG. 8 is a developed view of the grooved roller.  
 DETAILED DESCRIPTION OF THE INVENTION The grey yarn which is to be twisted in the twisting step of the present invention is a gyratory (or torqueimparted) crimped yarn obtained from a common twisting heat setting untwisting process. Every bulked portion is well crimped and each filament therein presents a finely crimped configuration, providing a well crimped yarn portion, while every nonbulked portion is insufficiently crimped and each filament therein is much the same as a non-processed filament, providing a roughly crimped yarn portion. If extra twist, even ifslight in degree, is given to such yarn, such twist is concentrated in the non-bulked portions which are in an easily twistable state, and as a result of this, the filaments in each of said non-bulked portion are further bundled up, thus making the difference between the bulked and non-bulked portions more conspicuous. As the torsional torque built up by such locally concentrated twist is balanced, such torque works exclusively on the bulked portions and produces a synergistic effect with the inherent crimping torque of the bulked portions, thereby developing a high retracting ability.  
  Thus, if even slight twist is given to the yarn, such twist is concentrated locally in the non-bulked portions.  
  This performance is further described with reference to FIG. 2.  
  FIG. 2 is a model drawing showing the change in the lengths of a bulked portion 1 and of a non-bulked por tion 2 according to the number of twists given. In&#39;the figure, references numeral 3 represents the case where the number of twist is zero, and 4 and 5 represent, respeetively, the cases where the number of twists has been gradually increased. It will be seen that as the number of twists increases, the length of the nonbulked portion 2 where the twist: is concentrated in proportionally increased as indicate-d by 2&#39; and 2&#34;, and the apparent number of twists in the non-bulked portion also increases.  
  Also, the apparent diameter ratio signifying the difference in bulkiness between the bulked and nonbulked portions is naturally changed, that is, increased proportionally to the number of twist given.  
  Table 1 below shows the results of actual measurements conducted on denier-36 polyester filaments and 40 denier-l7 nylon filaments obtained according to the present invention. The number of twist given is expressed by twist/meter.  
 Table 1 number length of length of apparent apparent material of bulked non-bulked diameter ratio number of twist portion portion between bulked twist in and non-bulked non-bulked portion portion polyester t/m t/m 75d-36f 70 88.9 11.1 1.7 6306 100 85.2 14.8 2.1 675.7 160 81.3 18.7 2.2 855.6 nylon 40d-17f 70 85.3 14.7 1.4 476.2 100 82.7 17.3 1.6 578.0 160 74.8 25.2 1.62 634.9 300 85.1 34.9 1.5 859.6  
  Referring to FIG. 3, plural pieces of grey yarn 6, 6 are first bundled up by a fixed guide 7, then passed through feed rollers 8, grooved roller 9, fixed guides 10, 10, heater 11, false twisting spindle l2 and delivery roller 13, and then wound up on the respective take-up mechanisms 14, 14&#39;. During this process, the grey yarns 6, 6&#39; are moved reciprocatingly while engaged in the groove in said grooved roller 9 and are then separated into the individual yarns 6, 6&#39; and further guided by the respective fixed guides 10, 10&#39;, so that tension of the yarns 6, 6&#39; is changed periodically with the rotation of the grooved roller 9.  
  The groove formed in the grooved roller 9 for guiding the yarns while engaging them therein is formed in a zigzag in the surface, as shown in FIGS. 7 and 8, so as to let the yarns therein traverse in accordance with rotation of the roller. The two yarns guided into the groove are caught in a parallelled state at a point 15 and more successively from the position of FIG. 4 to the position of FIG. 5 and then to the position of FIG. 6 with every rotation of the roller in the same direction as the direction of advancement of the yarns. Numeral 16 indicates a doubling point for the yarns.  
  In the situation of FIG. 4, both yarns 6, 6 are under the same tension and undergo normal false twisting in a parallelled state, but in the situations of FIGS. 5 and 6, since the point 15 moves to the right or to the left in accordance with rotation of the roller 9, there is created a difference in tension between the two yarns 6, 6. In this situation of FIG. 5, the tension of the yarn 6 becomes greater than that of the yarn 6, so that when twisting occurs by the false twisting spindle under this condition, the yarn 6 with the smaller tension is given sufficient twist while the yarn 6 with the greater tension resists twisting, and as a result, though the yarn 6 is afforded sufficient crimping, the yarn 6 is not given sufficient crimping. Then, when the situation is changed into that of FIG. 6, the tension relation between the two yarns is reversed, and hence behavior occurs which is just the opposite of the case of FIG. 5. As the operations of FIGS. 4, 5 and 6 are performed repetitively with the advancement of the yarns and with the rotation of the grooved roller 9, there is consequently obtained a partially bulked yarn. The thus obtained bulked yarn is given extra twist by a twisting machine which is not shown. Instead of giving such extra twisting after the aforedescribed process, the material yarns 6, 6 may be given a similar twist before passing through the aforedescribed process.  
  According to the present invention, as described above, twist is accumulated predominantly in the easily twistable non-bulked portions of the yarn having the bulked and non-bulked portions arranged alternately along its length, so that the difference between both portions is very conspicuous and the latent torque in the filaments is increased. Therefore, when a texture is made by using such yarn, there is obtained a crimped fabric having a prominent creping effect and good feeling.  
  It is also possible in the present invention to optionally change the number of the bulked portions in unit length and to increase the yarn processing speed by changing the rotational frequency of the grooved roller 9.  
  Evaluation of the fabrics made by using the partially crimped yarn obtained from the method of the present invention showed that the number of twist including additional twist, given to the yarns should be within the limit of 500 twist/meter; if such limit is exceeded the feeling of the fabric is impaired and the creping effect is diminshed, producing a flattened texture. For obtain&#39; ing the best results for both feeling and creping effect, the number of twists should be 50 to 200 twist/meter.  
 EXAMPLE Two pieces of grey yarns comprising denier24 polyester filaments twisted at twist/meter were fed to a false twisting process such as shown in FIG. 3 and processed under the following conditions: twisting spindle rotational frequency 95,000 turns/min; false twist number 100 twist/meter; heater temperature 220C; range of movement of point 15 in the grooved roller 10 mm; grooved roller rotational frequency 2,000 turns/- min; and yarn feed tension 14 grs. There was consequently obtained a partially bulked yarn having the following features: length of one unit of bulked and nonbulked portions 25 mm; rate of length of bulked portion to length of non-bulked portion 82 l8; apparent number of twist in non-bulked portion 835 twist/meter; and apparent diameter ratio between bulked and nonbulked portions 2.8.  
 What is claimed is:  
  1. A method of producing a partially bulked yarn comprising the steps of alternately giving uniform tension and non-uniform tension to more than two pieces of thermoplastic synthetic filaments, performing periodic changes of tension between said filaments. bundling said filaments, passing the bundled filaments through a heater and a false twisting spindle to form a partially bulked yarn having alternately arranged bulked and non-bulked portions, and then giving additional twist to said yarn at 50 to 500 twist/meter.  
  2. A method of producing a partially bulked yarn comprising the steps of giving twist to thermoplastic filaments at 50 to 500 twist/meter, alternately giving uniform tension and non-uniform tension to more than two pieces of the twisted thermoplastic synthetic filaments, performing periodic changes in tension between rollers, a filament guide roller having formed therearound a filament guide groove, fixed guides adapted to hold corresponding filaments emerging from said groove, a fixed guide for bundling said filaments, a  
 heater, a false twisting spindle, and twisting means.