US2705348A - Drawing of slivers - Google Patents

Description

, Filed May 19, 1950 DRAWING 0F SLIVERS 1N VENTOR RUDOLF KERN WERNER PAUEN BY uy/ ATTORNEY United States Patent DRAWING OF SLIVERS Rudolf Kern, Bonn, and Werner Pauen, Dusseldorf, Germany Application May 19, 1950, Serial No. 177,468

Claims priority, application Germany May 20, 1949 Claims. (Cl. 19-131) This invention relates to new and useful improvements in the drawing of slivers. More particularly the invention concerns an improvement in the drawing mechanism of pre-spinning and fine spinning devices.

One object of the invention is among others an 1mproved draft in the drawing of fiber slivers. This and further objects of the invention will be apparent from the following description.

In accordance with the invention all fibers of a sliver are moved by a fiber securing transport between the entering or back roll and the delivery or front roll of a drawing machine for a distance therebetween of at least half the length and preferably the entire length of the largest fiber in the sliver and at a lesser speed than the circumferential speed of said front roll, the fibers being held so tightly by said transport that fibers above predetermined length are moved by the front roll only when being gripped thereby while any shorter fibers are so moved only after having completely left said transport.

Within the preferred embodiment of the invention therefore the transport extends practically the entire distance between the back roll and the front roll and passes the fibers of the sliver to within the closest proximity of the front or delivery roll.

The rate of advance of the transport is substantially equal that of the back roll or preferably somewhat higher so that the sliver may be passed on to the transport under light tension.

When reference is made herein to the expression sliver or where such similar term is used there is intended to be designated thereby any conglomerate of fibers as it is conventionally subjected to a drawing operation in the pre-treatment of fibers for the spinning thereof into yarn and including card slivers, combed slivers, gilled slivers, roving and slubbing.

This positive fiber transport is obtained in accordance with the invention by way of a pulling-through drawing arrangement in that there is provided between the back roll and front roll a surface continuously moving in the direction of the movement of the sliver such as an endless tape or an appropriately large roll, the surface of which possesses such a grip for the fibers that the same are retained in position on the roll against the force of a pull exerted upon them by other fibers which are drawn by the front roll.

The transport is preferably so arranged between the front and back rolls that the fibers pass along a portion of the circumference of these rolls. This makes it possible to provide for a particularly short passage from the transport on to the front roll. When treating combed slivers this distance between transport and front roll may be made advantageously shorter than the length of the combed out fibers.

The surface of the roll or endless tape may be suitably roughened for the purpose of imparting thereto the required gripping action such as by providing the same with flutes, teeth, pins, projections or similar expedients. It is in many cases desirable to press the sliver on to or against the surface of the transport such as by a dabbing roll or by small straps or thongs. These last-mentioned expedients for pressing the sliver against the transport may be driven by the surface on to or against which the sliver is pressed.

When practicing the invention it is possible without difiiculty to obtain drafts, i. e., ratios of delivery from the front roll to speed of entering of sliver on the back ice roll which exceed twice the drafts obtainable with currently practiced drawing methods. While ordinary finishers today permit drafts of a maximum of 4.5, it is possible in accordance with the invention to obtain without difficulty thirty times the draft. It is thus possible to materially reduce the number of drawing devices or machines and thus the number of spinning machines. The advantages of the invention are applicable to all drawing devices or machines of all types, i. e., regardless of whether they are of the pre-spinning or fine-spinning stage.

The invention is particularly applicable to long staple fibers that may be also used in connection with short staple fibers.

Some of the modern drawing devices or machines provide supports for guiding short fibers which float between the back and front roller pairs. These are usually in the form of a pair of pulling-through cylinders which permit the longer fibers that are in gripping contact with the front or delivery roll to be passed. through while the shorter fibers are stopped by sluice-type funnel. Even with such type drawing devices only relatively low drafts are obtainable since the short fibers which are embedded within the long fibers or which rest upon the latter will be pulled along in the free interspaces between the cylinder palts.

Higher drafts are obtainable with the previously known drawing machines or devices of the strap or thong or double strap type in which the fibers are transported on or between straps or thongs of leather or similar material being thereby retarded in their movement towards the pair of delivery rolls establishing in this manner a speed differential between the transport on or between the straps or thongs and the gripping delivery roller pairs. The straps or thongs, however, do not prevent that the long fibers which are gripped by the front or delivery roll will pull the shorter fibers along. For this reason, therefore, strap or thong drawing devices do not give drafts which are appreciably above other conventionally obtained draft values. Furthermore, these strap or thong drawing devices have found practical application only for short staple fibers while the invention is particularly designed for use With long staple fibers.

Another spinning method for combed slivers with a maximum of mm. staple length has become known. An increased draft is obtained in this method by tearing the fibers above 80 mm. length between drawing rolls which are under high load. This method has the disadvantage that the valuable long fibers are destroyed, that its application is only possible for certain raw materials and that the number of doublings is restricted during the preparation thus also restricting the mixing and uniformity of the slivers.

The invention is free from the above-mentioned disadvantages and drawbacks. It is particularly useful for long staple fibers and specially designed for saving the long fibers.

The invention is illustrated by way of exemplification in the drawings, in which Fig. 1 is a diagrammatic side view of a drawing frame in accordance with the invention; and

Figs. 2, 3, and 4 are embodiments of rollers of the drawing frame shown in Fig. 1.

In the drawing frame as illustrated in Fig. l, the sliver 11 is drawn in by the feed roller pair 12-13. The upper roller 12 of the feed roller pair is covered with leather or the like in the conventional manner, while the lower roller 13 is a conventionally fluted roller. Sliver 11 is delivered by the front or delivery roll pair 14-15, which is constructed similar to the feed roller pair 12-13, with an appreciably greater speed than it is drawn into the device by the feed roller pair. Delivery roll 14 may be weighted or not, as may be appropriate or desired in accordance with the particular spinning stage. A guide roll 18 having a substantially larger diameter than either of the delivery rolls is positioned between the feed roller and the delivery roll pair adjacent to the delivery roll, so that the sliver will pass over at least /3 of its circumference. The size of this roller should be such that at least A2 and preferably a length of sliver equal to at least the maximum fiber length is in contact with this guide roll. The

surface of this guide roll is provided with gripping or fiber-holding means.

A strap or throng 19, guided in frame 20 by rollers 21, 22, and 23 is positioned for pressing the sliver in contact with the guide roll. The frame 20 is pivotable relative to pivot post 24, and carries slide track 25, provided with slide weight 26, which may be secured in position by wing nut 27. Strap or throng 19 can be thus placed upon roll 18 by pivoting the frame around pivot post 24 and will then be pressed against the surface of roll 18, adapting itself to the surface contours thereof. The same is then transported by reason of its frictional engagement with roll 18. The pressure may be shifted to intake or delivery by changing the position of the sliding weight.

The guide member 23 is constituted as a guide needle or pin of such small diameter that the strap or throng 19 presses the sliver against roll 18 up to immediately preceding its arrival on the front or delivery roll 14. Guide pin 23 may be adjusted horizontally as well as vertically.

The guide roll 18, the guide member 23, and the delivery roll pair 1415 are so positioned, as shown, that the sliver will leave the guide roll 18 at an angle approximately tangential thereto at the point at which it is pressed against the drive roll by the strap or throng 19 at the guide member 23. The guide member 23 has a radius of curvature which is much smaller than the radius of curvature of the delivery roll.

The guide roll should rotate at substantially the same peripheral speed as the feed roller pair, the peripheral speed of the guide roll should never be in excess of 20% and preferably at the most higher than that of the feed roll 12.

The particular manner in which an increased gripping action may be obtained for the surface of the sliver transport in accordance with the invention depends upon conditions and particularly upon the type of fibers, material of the transport surface and its speed of travel and in certain cases also upon the devices or expedients used for pressing the sliver against the transporting surface. Thus roll 18 may be made of metal, wood, pressure molded resins or similar materials, and its surface may be provided with projections for carrying the fibers along or, for instance, with flutes, channels, netting, ropes, etc. or with any other suitable roughening of any type well known in the art. Fig. 2 shows a deeply fluted roll 18a While Fig. 3 illustrates a roll 18b composed of multiple circular sections 180 and intermediate separating rings 18d.

Fig. 4 shows a roll 18e which is provided with a coating of projecting hard granules, such as, for instance, an emery sleeve. Rolls as shown in Fig. 4 are in general particularly suitable for fine-spinning machines, while for coarser material preparing machines and heavier slivers, as for instance, combed slivers, there may be either used coarse grained coatings or relatively coarse flutes as shown in Figs. 2 and 3, and into which individual fiber strands will be pulled. When using an arrangement of a roll according to Fig. 1, the distance which the sliver traverses between its take-off from roll 18 and its passage onto delivery or front roll 14 may be varied to almost any desired shortness. It is also possible to position the back roll 12 so close to roll 18 that the sliver 11 is supported practically throughout its entire travel through the device. It is thus possible with such an arrangement to place the front or delivery roll 14 so close to the roll 18 that practically all of the fibers of sliver 11 are held in position on roll 18 until they are individually gripped by roll 14.

For the purpose of reguating the draft and the speed of rotation of the front or delivery rolls there is provided, in addition to the gear train situated between the front and back rollers or back roller drives, a variable transmission, preferably of the continuous (non-stepped) type. The drive of roll 18 is preferably obtained from the same motive power as the drive for the back rollers and is then preferably obtained by way of a gear train through which a certain over-drive if desired of the sliver-gripping transport roll may be obtained relative the back roll. As already previously set forth, it is of advantage that the gripping surface possesses a certain overspeed relative the back roll so that the sliver may be passed onto the transport surface with a certain tension.

In applying this procedure the advantages may be considerably increased. If, for instance, in the end-passages of worsted yarn preparation drawing devices in accordance with the invention were used in only two successive machines with the thirty times draft in each, there would be obtained after the second passage a total draft of 30 30=900, while it was up to now only possible to obtain a total draft of at the most 4.5 4.5=20. A total draft of 900 is so high that the sliver even with multiple doubling cannot be spun any more without a further finishing. Inasmuch as at least a increase in draft is obtained when using the invention in connection with ring spinning, it is possible when applying the invention to short-cut several preparation and sliver thinning passages and to thus reduce the entire spinning procedure by at least 50% and to correspondingly reduce the number of spinning machines. Thus, for instance, an ordinary ring spinning machine was altered by providing the same with drawing devices in accordance with this invention. Forty to sixty times the draft were obtained and instead of spinning the yarn from the eighth preparation step, it was possible to take the same from the fifth to sixth steps.

The fullest utilization of the high drafts obtainable in accordance with the invention is not so much limited by the technical factors involved in the speed differential between front and back rolls but rather by the fact that currently available preparation slivers are not sufliciently uniform and have to be made uniform by doubling. The use of relatively high drafts is furthermore limited in those cases in which mixtures of different fibers are desired or required.

We claim:

1. Drawing device for spinning machines comprising feed roll means, delivery roll means positioned in spaced relation and substantially parallel to said feed roll means, a guide roll having a substantially larger diameter than said delivery roll means positioned between said feed roll means and delivery roll means adjacent said delivery roll means for contact with a sliver being passed through said feed roll means and delivery roll means over a substantial portion of its circumference, a flexible belt guided around at least two spaced-apart guide members positioned for pressing said sliver in contact with said guide roll, one of said guide members being a curved guide member having a substantially smaller radius of curvature than said delivery roll means and being positioned adjacent said guide roll and delivery roll means in the space defined therebetween, defining the run-ofi point of the sliver from the guide roll to the delivery roll means, and means for imparting rotary motion to said feed roll means and said guide roll at substantially the same peripheral speed and to said delivery roll means at a substantially greater peripheral speed.

2. Drawing device according to claim 1, in which said flexible belt is positioned for contact with the upper portion of the surface of said guide roll and in which said guide roll is dimensioned and positioned for surface contact with a sliver being passed through said feed roll means and delivery roll means over at least one-third of its circumference.

3. Drawing device according to claim 1, in which said curved guide member is adjustably positioned for varying the run-off point of the sliver from the guide roll to the delivery roll means.

4. Drawing device according to claim 1, in which said feed roll means is positioned adjacent said guide roll.

5. Drawing device according to claim 1, in which said flexible belt is mounted on roll means positioned in a frame having a weight movably slidable between said feed roll means and delivery roll means.

6. Drawing device according to claim 1, in which said flexible belt is guided on roll means mounted in a hinged frame.

7. Drawing device according to claim 6, in which said hinged frame has a weight movably slidable between said feed roll means and delivery roll means.

8. Drawing device according to claim 1, in which the surface of said guide roll is of suflicient roughness to hold fast against transverse and longitudinal motion of any fiber of the sliver in surface contact therewith.

9. Drawing device according to claim 1, in which said guide roll has multiple projections extending from the surface thereof.

10. Drawing device according to claim 1, in which said flexible belt is guided around three of said spacedapart guide members positioned for pressing said sliver in contact with said guide roll.

(References on following page) References Cited in the file of this patent 2,497,511

UNITED STATES PATENTS 339,329 Schiefner Apr. 6, 1886 19,984 391,781 Cheyne Oct. 30, 1888 5 428,738 1,433,529 Butler Oct. 31, 1922 672,957 1,545,803 Vanni July 14, 1925 6 Neisler Feb. 14, 1950 FOREIGN PATENTS Great Britain of 1910 Germany May 11, 1926 France Sept. 24, 1929

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