US2953289A - Yarn handling - Google Patents

Description

p 1960 w. o. YOUNG, JR

YARN HANDLING Filed Sept. 16, 1954 INVENTCR WILLMM Oll ER YOUNQ,JR.

ATTORNEY United States, Patent YARN HANDLING William Oliver Young, Jr., Camden, S.C., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Sept. 16, 1954, Ser. No. 456,388

9 Claims. (Cl. 2267) This invention relates to apparatus for preventing filament wraps on guiding or delivery rolls used in the processing of textile yarn or tow and to an improved method of guiding and advancing a running yarn or tow of filaments. The invention'is especially directed to delivery rolls capable of advancing yarn and tow under substantial tension and releasing them to fall freely on to a suitable collecting surface without wrap formation.

Whenever a yarn or tow consisting of many fine filaments is processed and conducted by means of rolls, the tendency of the filaments to adhere to the rolls, strip back, and ultimately wrap therearound is every present. The condition becomes an even greater problem when the tow leaves the rolls in a state of very low tension as in the .case of free falling or piddling on to a collecting belt or other surface. Various proposals for reducing wraps such as air wipers, doctor blades and the like have met with some success in improving continuity of operation, but these have not been altogether satisfactory solutions to the problem since the tendency to wrap is still present and the corrective measure merely attempts to prevent a strip back from growing to serious proportions.

It is, therefore, an object of this invention to provide a novel yarn, strand or tow guiding or advancing appartus. Another object of this invention is to provide an improved method of handling running yarns and tows of filaments without encountering filament wraps. Other objects will be apparent from the description of the invention that follows.

In the figures:

Figure 1 is a side section view taken on line 1-1 of Figure 2, showing one of the rolls in section, and

Figure 2 is a front section taken on line 22 of Figure 1, including, for convenience, a showing of a pair of rolls in nip formation by dotted lines since they are to the left of line 2--2.

The objects of this invention are accomplished by the use of guiding or delivery rolls for running yarns, strands, tows and the like provided over their entire filamentcontacting surfaces with closely spaced, minute passages for air or other gaseous fluid, such as nitrogen, carbon dioxide or dry steam, to be forced outwardly from Within and thus prevent any tendency for the filaments to wrap therearound. The very minute size and very close spacing of the gaseous fluid passages coupled with an internal pressure of from about 50 to about 100 pounds per square inch (gauge) causes an untensioned filament to float on the fluid layer surrounding the roll without any adherence to the roll surface. essentially a surface phenomenon and my little disturbance can be observed at over /4 inch or so away from the roll. Of course, when the rolls are being used to form a nip and filamentary material is passed therebetween, one roll being pressed against the other, floating.

will not occur, but should a filament become broken or untensioned beyond the nip, the floating effect will prevent it from wrapping.

The effective gas flow is.

The process thus comprises feeding filamentary ma terial to a rotating member which has a foraminous shell and a porous working surface, through which shell a fluid under pressure passes from the interior through the pores to the outside surface and into the atmosphere. A rotating surface emits the high velocity fluid which exerts a localized radial repulsing force against the filamentary material at all times. This force is effective, depending upon the pressures used and pressure drops occurring, usually within A inch or so away from the roll, and acts on the filamentary material at all times that the material is within such distances from the working surface. This effectively prevents wraps.

With reference to the drawings, 1 is a frame suitably mounted on a support (not shown). Within this frame are located shafts for driving and supporting two (see Figure 2) external tow delivery rolls 2, of the type previously mentioned, forming a nip 41 through which tow 42 passes. One of these shafts 3 is fixedly supported in suitable bearings mounted on the inside surfaces of the front and back walls of the frame while shaft 4 is mounted on a subframe 5 for movement toward and away from the fixed roll shaft 3. The subframe comprises a plate 6 carrying two pillow bearing blocks 7 supporting shaft 4. To the upper end of plate 6 are fastened two mounts 8 for suspending plate 6 from pivot shaft 9 which is fastened to the mounts by means of set screws in tapped holes 10. The two blocks 7 and mounts 8 may be seen in Figure 1. Shaft 9 is supported in two bearings 11 fastened to the inside front and back walls of the frame II. To the bottom of plate 6 is welded a plate support .12 carrying a bracket 13 to which is attached the end of the piston rod from an air cylinder 14 which exerts a constant pressure tending to keep roll 2 on shaft 4 against roll 2 on shaft 3. Air cylinder 14 is hingeably mounted to bracket 15 fastened to the side wall of frame 1. I

The delivery roll shafts 3 and 4 are driven at the same speed by means of sprockets and a chain 17 as shown in the figures. Shaft 16 with a sprocket is the driver, it being driven preferably from a motor through a PIV or other variable drive to give the desired speed control. In addition to passing around the sprockets on shafts 3 and 4, the chain 17 passes around an idler sprocket on shaft 19 so mounted as to maintain substantially constant tension on the chain regardless of the position of the movable shaft 4. Shaft 19 is rotatably supported in two end pillow block bearings 20 fixed to plate 21 which is swingable about the center of shaft 22 which, in turn, is supported by a bracket 23 with two bearings 24 to the wall of frame 1. At the opposite end of plate 21 is a bracket 25 and to this is pinned a clevis fastened to the end of the piston shaft of air cylinder 26 which is attached to the bottom of frame 1 by means of bracket 27.

As shown in Figure l by the cross-sectional view of the roll 2 mounted on shaft 4, the delivery rolls 2 are constructed of a foraminous cylindrical shell 30, for instance, of sintered metal such as microporous stainless steel or microporous bronze which provide an infinite number of very fine passages for air or the like. cross-sectional area of each passage preferably is of the same order of magnitude as the cross-sectional area of an individual filament, for instance, about to about 500 square microns (about 10 to about 25 microns diameter if the openings were circular). The foraminous cylindrical shells are concentrically supported near the end of the shafts 3 and 4 by two end flanges 31 and 32, which flanges are keyed to the shafts to insure rotation therewith. Thrust collars 33 serve to space the rolls from the frame and together with cap screws 34 and two gaskets 35 for each roll provide sufficient end pressure to insure an air tight fit between the ends of the foraminous shell and the Patented Sept; 20, 1960 The flanges. The shafts 3 and 4 are axially drilled from end to end, and connecting with the resultant passageway 37 are a plurality of radial holes 36 between the end flanges 31 and 32. At the roll end of the shaft, the axial drilling is blanked off by cap screw 34, providing for the introduction of a gaseous fluid such as air into the spaces between the shells 30 and the shafts. For protection of the foraminous cylindrical shells when no yarn or tow is therebtween, the outer diameter of the end flanges is made very slightly larger in diameter, e.g. 0.008 inch, thus preventing the shell surfaces for contacting each other.

At the end of shafts 3 and 4 opposite to the location of the rolls, there is provided a gas-tight chamber. The cap plate 38 of this chamber is tapped for a pipe connection 39 communicating with a source of air or other gaseous medium at the desired pressure. The connection to the fixed roll shaft 3 may be rigid, but to the movable roll shaft 4 a flexible connection is required. When air is supplied at 70 or 80 pounds per square inch gauge pressure, this pressure is substantially maintained at the chamber within the tow delivery rolls and a pressure drop of substantially this amount takes place in traversing the microporous shell.

While yarns and filament bundles of any size may be effectively guided or advanced by the apparatus of this invention, this specific arrangement just described is especially suited to the handling of very large tows or filament bundles having a total denier of 100,000 and more comprised of 20,000 or more filaments. By properly setting the roll pressure and surface speed of the rolls, very effective uniform advancement of the filament bundle is accomplished without slip. In view of the very fine miscroscopic openings in the rolls, it is desirable to filter the air or other gaseous medium used carefully to avoid stoppage of the fine openings. Gas pressures of at least 50 pounds per square inch gauge are necessary and pressures as high as 100 pounds per square inch are satisfactory. Air pressures of about 70 to about 80 pounds per square inch gauge are preferred.

Even though a tow of filaments is fed vertically down into the bite of the rolls at a tension of 50 or more pounds and drops vertically down from between the rolls at a very low tension (due only to the weight of the tow between the nip and the point of collection), there is not the slightest tendency for filaments to wrap around either of the rolls. A uniform outwardly moving layer of gas envelops the foraminous cylindrical part of the roll for a distance of about inch except at the bite and, even here, air may be emitted when the surface is sufliciently clear of filaments to permit the passage of the gas. The actual consumption of air or other gas is surprisingly small and yet an untensioned filament bundle wet or dry cannot be made to adhere to the roll surface.

While the need for wrap-preventing guide rolls of the type herein described is not as great as for delivery or feed rolls, such guide rolls may be used at times advantageously. Single guide rolls are generally used at any one position since the object is largely a matter of changing direction of the running yarn or the like and in such use, the roll may be yarn driven or mechanically driven as desired. Thus, while the figures relate to the use of the rolls of this invention in pairs, a single roll can be used with advantage as a directional guide roll or in reducing frictional contact in the advancing of filaments. Obviously, the use of this type roll for guiding permits many changes and simplification of the design.

The process and apparatus of this invention may be applied to any of the synthetic or natural filament or fiber bundles. For example, regenerated cellulose tows, cellulose acetate and other cellulose derivative tows, polyamide filament bundles, polyester filament bundles, polyacrylonitrile filament bundles, as well as slivers, tops and the like of cotton, wool, linen and similar materials may be handled in accordance with this invention.

Any departure from the above description which conforms to the present invention is intended to be included within the scope of the claims.

I claim:

1. The process of feeding filamentary material over and beyond a rotatable member which comprises feeding said material to said rotating member, simultaneously passing a gaseous fluid under uniform pressure into the interior of said member, and forcing said fluid through a multiplicity of randomly spaced minute passages which are distributed over the entire peripheral surface of said member to form a continuous gaseous layer about said member, said gaseous layer exerting a continuous uniform radial repulsing force against the filamentary material thereby preventing the material from wrapping around said member.

2. The process of claim 1 wherein said pressure is about 50 to pounds per square inch gage and the cross-sectional area of said passages is from about 100 to 500 square microns.

3. The process of claim 1 wherein said filamentary material is in the form of a tow.

4. The process of transferring and delivering tow comprised of fine filamentary strands which comprises passing said filamentary strands through a nip formed by two rotatable members positioned in side-by-side relationship, forming a continuous gaseous layer about each of said members by passing a gaseous fluid under uniform pressure into the interior of each of said rotatable members and forcing said fiuid through a multiplicity of randomly spaced minute passages which are distributed over the entire peripheral surface of said members, said gaseous layer exerting a continuous uniform radial repulsing force against said filamentary strands thereby preventing said strands from wrapping about said members.

5. Apparatus adapted to transfer and deliver tow comprised of fine filamentary strands which comprises a roll rotatably mounted on a shaft, said roll having a hollow chamber therein and a smooth peripheral surface containing a multiplicity of randomly spaced minute passages in communication with said hollow chamber, said passages being distributed over the entire peripheral surface of said roll, means for delivering a gaseous fluid under pressure to said hollow chamber whereby said fluid passes outward? 1y through said passages forming a continuous gaseous layer about said surface, and means for passing said tow over the surface of said roll.

6. The apparatus of claim 5 in which the average di ameter of the passages is from about 10 microns to 25 microns.

7. Apparatus adapted to transfer and deliver tow comprised of fine filamentary strands which comprises two rolls rotatably mounted in side-by-side relationship to form a nip, means for spacing said rolls apart to permit the passage of said filamentary strands therebetween, each of said rolls having a hollow chamber therein and a smooth peripheral surface, said peripheral surface containing a multiplicity of randomly spaced minute passages in communication with said hollow chamber, said passages being distributed over the entire peripheral surface of each of said rolls, means for supplying a gaseous fluid under pressure to said hollow chamber whereby said fluid passes outwardly through said passages forming a continuous gaseous layer about said surfaces, and means for passing said tow through the nip formed by said rolls.

8. The apparatus of claim 7 in which the passages have an average diameter between 10 microns and 25 microns.

9. The apparatus of claim 7 in which one of the rolls is pivotally mounted.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS 1 6 Nazel Feb. 16, 1915 Ruby Apr. 24, 1917 Meyer May 31, 1927 Knebusch et al Sept. 26, 1939 McDermott Aug. 17, 1948 Slayter Jan. 3, 1956

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