US2990673A - Process and apparatus for producing core yarns - Google Patents

Description

July 4, 1961 E. M. ADKINS, JR 2,990,673

PROCESS AND APPARATUS FOR PRODUCING CORE YARNS Filed Jan. 6, 1954 IN V EN TOR. fuss/Ye M ADKIN JP.

United States Patent 2,990,673 PROCESS AND APPARATUS FOR PRODUCING CORE YARNS I Eugene M. Adkins, Jr., Burlington, NC, assignor to Celanese Corporation of America, New York, N.Y., a corporation of Delaware Filed Jan. 6, 1954, Ser. No. 402,453 Claims. (Cl. 57-'-36) This invention relates to composite yarns and relates more particularly to the production of the type of composite yarns known as core yarns.

Core yarns are textile structures which generally consist of a core material, usually a strong fine yarn formed of a plurality of continuous filaments or staple fibers, more or less hidden within an outer layer of staple fibers drafted and twisted around said core material. These core yarns have been produced by a process termed Belgian doubling in the art, which is carried out on a spinning frame, which frame comprises a plurality of pairs of drafting rolls, including a pair of front rolls, and a spinning bobbin mounted in a twisting and winding device such as a ring twister. A roving of staple fibers is led through the drafting rolls to the nip of the front rolls while the thread which is to constitute the core material is led directly to the nip of said front rolls, by-passing the other drafting rolls. The core material and the drafted roving are twisted together as they proceed from the nip of the front rolls to the spinning bobbin.

Core yarns produced by the Belgian doubling process described above have been generally unsatisfactory in that the outer staple fibers do not completely cover the core material, particularly when the core yarn is of medium or fine count. This defect is especially noticeable when the core material and the covering fibers are of different colors or shades. For example, this defect may be readily observed after the dyeing of the core yarn, since the receptivity of the core material for the dye is usually different from the dye receptivity of the fibers constituting the outer layers of the core yarn and union dyeing of the core material and the covering fibers is, in many cases, difficult or impractical. Thus, cross dyed effects ordinarily are encountered, whether intentionally or not, so that the incompletely covered dyed core material can be seen through the dyed outer fibers and the yarn has an undesirable fiecked or streaked appearance. This appearance has restricted the use of core yarns mainly to novelty applications and has precluded the use of such yarns to a large extent in woven and knitted fabrics, even though the core material has imparted higher tensile strength and other desirable physical properties to the yarns.

It is an important object of this invention to provide a method and apparatus for the production of core yarns free from the foregoing and other disadvantages.

A further object of this invention is the provision of a novel and useful method and apparatus for producing core yarns.

Other objects of this invention will be apparent from the following detailed description and claims.

According to one embodiment of this invention a core yarn is produced by feeding a pair of spaced rovings of staple fibers through the drafting rolls of a spinning frame to the balloon guide of the ring twisting device of said frame, while the yarn which is to constitute the center or core of the core yarn is fed at a predetermined speed between said spaced rovings to said balloon guide, and is combined with the drafted rovings. The resulting composite filamentary material is twisted, as it passes to the spinning bobbin, to produce the core yarn. Core yarns produced according to this invention comprise a central core substantially completely covered by staple fibers.

When dyed such core yarns present a pleasing, uniform unstreaked appearance.

The accompanying drawing is a simplified view, mamly in perspective, of the apparatus of this invention.

Referring now to the drawing, reference numerals 11, 12 and 13, 14 and 16, 17 designate successive pairs of drafting rolls of a spinning frame, while reference numetal 18 designates generally the ring twisting portion of said spinning frame. In one suitable embodiment the lower rolls 11, 13 and 16 are fluted, metallic, positively driven rolls, while the upper rolls 12, 14 and 17 are covered rolls, pressed against the lower rolls in any suitable manner, as by weights (not shown) and driven by frictional contact with said lower rolls, all in a manner well known to the art. The spinning frame is of the type commonly employed for the spinning of ordinary yarn, with the following exceptions: Mounted on the spinning frame, above and slightly behind the front drafting rolls 16, 17 is an independently driven feed roll 19 (which may be driven by any suitable means, as through gear 20) for supplying the yarn 21, which is to constitute the center, or core, of the core yarn, to said front drafting rolls. Riding on the feed roll 19, and pressed thereagainst in any suitable manner, as by means of a weight (not shown), is a top roll 22, covered with any suitable material such as cork or synthetic rubber, while above the nip of the rolls 19 and 22 there is mounted a guide 23 for receiving the yarn 21 from any suitable source. The covering, or cot 24, of the upper front roll 17 is provided with a narrow circumferential groove 26 of width and depth sufficient to accommodate the yarn 21 so that said yarn 21 may pass through said groove at a speed independent of the speed of said front roll 17. Behind the rear drafting rolls 11, 12 there are mounted a pair of spaced funnel-shaped guides or trumpets 27 and 28 for receiving a pair of spaced rovings 29 and 31 of staple fiber; these two trumpets 27, 28 replace the single trumpet usually employed on spinning frames. It is to be understood, of course, that a conventional spinning frame comprises a large number of identical spinning positions for spinning a correspondingly large number of yarns, and that the changes indicated above may be made at one, several, or all of said spinning positions, as desired. Advantageously, the roll 19 extends the entire length of the spinning frame while separate rolls 22 are provided for each spinning position. Thus, each roll 22 may be raised to stop the feed of the yarn 21 which is in contact therewith, without interfering with the feed of similar yarns at other spinning positions, so that it is easy to start up operation or to replace a broken yarn at any one spinning position without affecting the other spinning positions.

To start the operation of spinning the core yarn, the yarn 21 is threaded through the guide 23, the nip of the rotating rollers 19 and 22, the groove 26 in the upper front roll 17 and the balloon guide 32 and traveler 33 of the ring twister 18 and is wrapped onto an empty driven bobbin 34 mounted in said ling twister. Advantageously, the bobbin 34 is held stationary, as by a brake, when the yarn 21 is first wrapped thereon and then is allowed to rotate so as to wind the yarn on the bobbin. The rovings 29 and 31 are drawn from suitable separate sources through the guides 27 and 28, between the successive pairs of rotating drafting rolls 11, 12 and 13, 14 to the nip of the rotating front rolls 16, 17, said rovings being maintained in spaced condition. The drafted rovings emerging from the nip of the front rolls 16, 17 are then thrown, manually or by any suitable mechanical device, onto the yarn 21 travelling to the balloon guide '32, causing said drafted rovings to begin to twist around said yarn 21. Thereafter, the rate of feed of the yarn 21 is adjusted relative to the rate of feed of the drafted rovings in order to ensure that in'the resulting 'core yarn the central core is completely covered. This adjustment of the feed rates may be accomplished by maintaining the speeds of the drafting rolls 11, 12, 13, 14, 16, 17 constant while regulating the speed of the feed roll 19, which feed roll may be driven in any suitable manner, e.g. through a train of gears connected to the driven front roll 16.

The rate at which it is necessary to drive the feed roll 19 in order to obtain a core yarn in which the yarn 21 is substantially completely covered by the staple fibers of the rovings 29 and 31 will depend on such factors as the type, fineness and weight per unit length of the rovings 29 and 31 and similar parameters of the yarn 21. However, the correct rate can be determined in any instance in a simple manner by examining the core yarn being produced and varying the speed of the feed roll 19 accordingly. Examination of the core yarn to determine completeness of covering is particularly easy when the core material and the covering fibers are of different colors, e.g. when the rovings are made of pigmented fibers. When inspection of the core yarn shows that the central thread is not completely covered the speed of the feed roll 19 should be decreased, while when the amount of coverage is greater than that desired the speed of the feed roll 19 may be increased. After the ratio of the speed of feed roll 19 to the speed of front rolls 16 and 17 has been determined by preliminary trials for any given rovings and yarns and any given spinning conditions, this ratio is maintained constant during the spinning operation.

Because of the presence of the groove 26, the front roll 17 acts as a guide for directing the yarn 21 substantially into the plane of the drafted rovings without substantially affecting the speed of said yarn 21. Naturally, the groove must be larger when a thick yarn 21, such as a rubber yarn, is employed, than when a fine yarn such as fine nylon yarn, is used.

The process and apparatus of this invention may be used with a wide variety of textile fibers, and are particularly suitable for use with synthetic textile fibers, such as fibers of cellulose acetate or other cellulose esters and ethers; fibers of polyamides such as nylon; fibers of vinyl polymers such as polyvinyl alcohol or the polymers and copolymers of acrylonitrile, vinyl chloride and ethylene; fibers of polyesters such as polyethylene terephthalate; cellulose fibers such as viscose rayon or high tenacity fibers of saponified stretched cellulose acetate; or fibers made from rubber latex. It is desirable, for best results, to employ a yarn of continuous filaments as the central portion, or core, of the core yarn. Thus, excellent results have been obtained when the yarn making up the central core is composed of continuous filaments of cellulose acetate, saponified stretched cellulose acetate or nylon while the rovings are made up of staple fibers of cellulose acetate, each staple fiber having a denier of about 2 or 3 and an average length of about 2 inches, said rovings having a total denier of the order of about 900 to 5300 each, for example, and having a small amount of twist, e.g. a twist of 0.8 to 2.0 turns per inch. It has been found advantageous to employ a yarn of continuous filaments which has no initial twist or which has an initial twist in a direction which is the same as the direction in which the composite or core yarn is to be twisted. However, if desired, the initial twist of the yarn which is to constitute the central core may be in a direction opposite to the direction in which this yarn and the drafted rovings are to be twisted together.

As is well known, it is not possible, on a practical basis, to produce very fine yarns, i.e. yarns of high count, composed of those staple fibers which have relatively low tenacities, e.g. cellulose acetate. However, by the use of this invention there have been produced, on a practical scale, very fine core yarns comprising continuous filaments of cellulose acetate surrounded by staple fibers of the same material. These core yarns are much finer than those produced solely from staple fibers of cellulose acetate and have properties superior to those of such staple fiber yarns, but have the general appearance of the staple fiber yarns. Other specific examples of core yarns which may be produced according to this invention include core yarns composed of one or more continuous filaments of rubber surrounded by staple fibers of any desired material, e.g. cellulose acetate or viscose rayon; core yarns composed of spun or continuous filament yarns of polyethylene terephthalate surrounded by blends of cellulose acetate staple fibers and wool fibers; core yarns composed of continuous filaments of cellulose acetate surrounded by blends of nylon and cellulose acetate staple fibers; core yarns composed of continuous filaments of polyethylene terephthalate or nylon covered by staple fibers of polyvinyl alcohol; and core yarns composed of continuous filaments of stretched cellulose acetate, either saponified or not, covered by a blend of staple fibers of cotton and stretched saponified cellulose acetate.

Although this invention is particularly applicable to the spinning of yarn, it may also be employed for the production of cored rovings by introducing two spaced ends of sliver, having adenier of, for example, about 12,000 to 45,000 instead of one, into a conventional roving frame, while introducing a yarn, between said ends of sliver, through a circumferential groove cut into the top front roll of said roving frame.

It is to be understood, of course, that while the invention has been described using a ring and traveler for effecting the twisting of the yarn and the drafted fibers, this twisting operation may be carried out in any other suitable manner, e.g. by the use of a cap or a flyer, both of which are well known to the art. In addition, the drafting rolls of the spinning frame may be provided, if desired, with one or more of the aprons conventionally employed with such rolls.

The following example is given to illustrate this invention further.

Example A pair of rovings, each of 1300 denier, and each composed of pigmented black crimped staple fibers of cellulose acetate, said fibers having an average denier of about 2 and an average length of about 2 inches, are fed to the rear rolls of a ring-spining frame modified in accord ance with this invention, which spinning frame is provided with an apron, of conventional construction, for transporting the rovings to the front rolls from the drafting rolls just behind said front rolls. The rear rolls of the spinning frame are driven at 1.3 feet per minute, while the front rolls of said frame are driven at 33.8 feet per minute. A yarn of white continuous filaments of stretched saponified cellulose acetate of high tenacity, said yarn having a denier of 30, is fed to the groove in said front rolls at a speed of 32 feet per minute and is thrown onto the spinning bobbin of said frame, which bobbin is rotated at 9,000 revolutions per minute. The drafted rovings leaving the front rolls of the spinning frame are thrown onto the yarn of continuous filaments passing to the spinning bobbin. The resulting core yarn has a uniform black appearance, the white central thread being completely and uniformly covered by the black pigmented staple fibers.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of my invention,

Having described my invention, what I desire to secure by Letters Patent is:

l. A frame for the production of core yarns, said frame comprising a pair of guides for receiving a pair of spaced rovings of staple fiber, a plurality of rolls for receiving said rovings from said pair of guides and for drafting said rovings in spaced condition and for positively feeding said drafted rovings to a point, means for positively feeding a yarn to said point, and means for twisting the resulting composite of rovings and yarn to wrap said staple fibers around said yarn, the construction and arrangement being such that said rovings are maintained separate and then converge at said point.

2. Apparatus for the production of core yarns, said apparatus comprising a driven yarn package support for winding and twisting filamentary material fed thereto, a pair of spaced guides, each receiving a roving of staple fiber, a plurality of rolls for receiving said rovings from said pair of guides and for drafting said rovings in spaced condition, said rolls including a pair of cooperating front rolls for positively feeding said drafted rovings to said driven yarn package support, and means for positively feeding a yarn to said driven yarn package support at a linear speed lower than the linear speed of said front rolls, the construction and arrangement being such that said rovings are maintained separate and then converge from said front rolls to said yarn.

3. Apparatus as set forth in claim 2, wherein said front rolls have spaced operative portions for engaging said rovings, and means for guiding said yarn between said spaced operative portions.

4. Apparatus as set forth in claim 3, wherein said means for guiding said yarn comprises a circumferential groove, between said spaced portions, for receiving and guiding the yarn from said means for positively feeding said yarn.

5. Apparatus as set forth in claim 4, wherein said means for positively feeding said yarn comprises a pair of feed rolls mounted above said front rolls, and said front rolls include upper and lower rolls, said upper roll being grooved circumferentially between said spaced portions for receiving said yarn from said feeding rolls.

6. Process for the production of core yarns, which comprises rotating a yarn package support for winding and twisting filamentary material thereon, positively feeding a plurality of spaced rovings of staple fibers to said rotating package support at a predetermined linear speed, positively feeding a yarn at a lower predetermined linear speed to said yarn package support and between said rovings, said rovings converging to meet at said yarn, whereby the rotation of said yarn package support twists the resulting composite filamentary material to wrap said staple fibers around said yarn.

7. Process as set forth in claim 6 in which said yarn is a continuous filament yarn.

8. Process for the production of core yiarns which comprises rotating a yarn pacage support for winding and twisting filamentary material thereon, drafting a pair of spaced rovings of staple fibers, positively feeding the resulting drafted rovings to said yarn package support at a predetermined linear speed, positively feeding a yarn at a lower predetermined linear speed to said yarn packagesupport and between said rovings, said rovings converging to meet at said yarn, whereby the rotation of said yarn package support twists the resulting composite filamentary material to wrap said staple fibers around said yarn.

9. Process as set forth in claim 8 in which said drafted rovings are positively fed to said rotating yarn package support by engagement of said drafted rovings between spaced operative portions of a pair of driven front rolls, and said positively fed yarn passes around one of said front rolls in a groove in said roll without being engaged by the other of said front rolls.

10. Process as set forth in claim 8 and in which said yarn is a substantially inelastic continuous filament yarn.

11. Process as set forth in claim 8 and in which said yarn is a substantially inelastic stretched saponified cellulose acetate continuous filament yarn of high tenacity.

12. Apparatus for producing core yarns comprising: a ring spinning frame having a roving creel, drawing rolls, spindles and rings and travelers; a support for a supply of continuous filament yarns, a yarn feed roll for positively advancing a continuous filament yarn from such supply toward each pair of front drawing rolls; means for driving said yarn feed roll at a surface speed slightly less than the surface speed of said front drawing rolls; and yarn guide means for guiding the continuous filament yarns from said yarn feed rolls between said front drawing rolls in longitudinal alignment with the centerline of ribbons of staple fibers passing between said front drawing rolls.

13. Apparatus for producing a core yarn comprising: a ring spinning frame having a roving creel, drawing rolls, a spindle and a ring and traveler; a support for a supply of continuous filament yarn; a yarn feed roll for positively advancing a continuous filament yarn from such supply toward the front drawing rolls; means for driving said yarn feed roll at a surface speed slightly less than the surface speed of said front drawing rolls; and yarn guide means for guiding the continuous filament yarn from said yarn feed roll between said front drawing rolls in longitudinal alignment with the centerline of a ribbon of staple fibers passing between said front drawing rolls.

14. Apparatus for producing a core yarn comprising: a ring spinning frame having a roving creel, drawing rolls, a spindle and a ring and traveler; a support for a supply of continuous filament yarn; yarn feed means for positively advancing a continuous filament yarn from such supply toward the front drawing rolls; means for driving said yarn feed means at a rate to advance said continuous filament yarn at a speed slightly less than the surface speed of said front drawing rolls; and yarn guide means for guiding the continuous filament yarn from said yarn feed means between said front drawing rolls in longitudinal alignment with the centerline of the ribbon of staple fibers passing between said front drawing rolls.

15. Apparatus for producing core yarns comprising: a ring spinning frame having a roving creel, drawing rolls, spindles and rings and travelers; a support for a supply of continuous filament yarns, a yarn feed roll for positively advancing a continuous filament yarn from such supply toward each pair of front drawing rolls; means for driving said yarn feed roll at a surface speed slightly less than the surface speed of said front drawing rolls; and yarn guide means for guiding the continuous filament yarns from said yarn feed rolls between said front drawing rolls in longitudinal alignment with the centerline of staple fibers in ribbon form passing between said front drawing rolls.

References Cited in the file of this patent UNITED STATES PATENTS 128,618 Harris July 2, 1872 2,061,498 Bird Nov. 17, 1936 2,076,270 Harris Apr. 6, 1937 2,210,884 Chittenden et a1. Aug. 13, 1940 2,234,338 Franke Mar. 11, 1941 2,263,614 Cote Nov. 25, 1941 2,309,095 Bry Ian. 26, 1943 2,526,523 Weiss Oct. 17, 1950 FOREIGN PATENTS 13,939 Great Britain of 1896

Images