US 3254820 A
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Description (OCR text may contain errors)
June 7, 1966 w. E. HAWKINS 3,254,820
SHOCK ABSORBING SYSTEM FOR YARN DELIVERY APPARATUS Filed June 15, 1964 h INVENTOR BY 27M K United States Patent 3,254,820 SHOCK ABSORBING SYSTEM FOR YARN DELIVERY APPARATUS William Edward Hawkins, Seaford, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del.,
a corporation of Delaware Filed June 15, 1964, Ser. No. 375,186
2 Claims. (Cl. 226-172) This invention relates to apparatus for delivering a running length of yarn or tow composed of a plurality of yarns and more particularly to means for handling running lengths of yarns or tow at high speeds for delivery onto conveyor belts or into containers from which the lengths are readily removed.
Since a yarn delivery device must pull the yarn or tow from a source assisted only by gravity, difliculty is usually encountered in static generation, yarn breakage, wrap formation, tension variation and the like. These diificulties are particularly serious when processing a tow composed of a large number of synthetic filaments or yarn ends. One method of yarn delivery which avoids many of these difliculties is to feed the yarn or tow into a nip formed by two endless belts running in close proximity. From the nip, the yarn is guided into a suitable container or disposed of in any other desirable fashion.
Yarn delivery apparatus of this type (referred to in the art as a belt piddler) is disclosed in U.S. Patent 3,061,164 to Valerius, issued on October 30, 1962, and U.S. Patent 2,805,765 to Saum et al., issued on September 10, 1957. While the belt piddlers described in these references are suitable for relatively low speed operation and may even be operated for short periods at higher speeds, they are not suitable for continuous commercial operation at high speeds, i.e., of the order of 1,000 to 1,500 yards per minute. At such higher speeds, the prior art devices tend to create irregularities in the delivery of the yarn or tow which cannot be overcome by the mere use of positive biasing means acting on the nip formed by the two endless belts.
An object of this invention is to provide an improved belt piddler which is suitable for delivery of tow or rope into a container in a uniform manner at high speed. Other objects will become apparent from the description hereinafter.
The objects of this invention are accomplished by a yarn delivery device which comprises two endless belts each mounted in vertical, spatial proximity on driving means and tension rolls and having a pair of oppositely disposed compression rolls which are adapted to contactthe two endless belts in such a manner that a short nip is formed by the belts for gripping and advancing the yarn or tow. The tension rolls have means associated therewith which maintain the endless belts in a taut relationship and absorb the shock created by the high speed of operation. Similarly, at least one of the compression rolls is provided with means which not only biases the compression roll to maintain the nip but also absorbs the resultant shock.
The accomplishment of these objectives can be seen by reference to the figures given for illustrative purposes and to the description below:
FIGURE 1 is a front view of the belt piddler; and,
FIGURE 2 is a schematic front view of the preferred embodiment of this invention.
With reference to FIGURE 1, there are two endles belts, designated 1 and 2, which are mounted in such a manner as to come into close proximity and form a short nip during a part of their respective travel. Belt 1 is mounted on rollers 3 and 4 being driven by roller 3 and belt 2 is similarly mounted on rollers 5 and 6 being driven by roller 5. These belts are made to contact or 3,254,820 Patented June 7, 1966 almost contact each other by the placement of compression rollers 7 and 8. Idler rollers 9 and 10 serve to fix the angle at which belts 1 and 2 leave compression rollers 7 and 8. The angle at which the belts approach the compression rollers is, of course,-fixed by the placement of drive rollers 3 and 5 relative to compression rollers 7 and 8. The drive rollers and idler rollers 9 and 10 are positioned so that a relatively short nip is formed and.
so there is some angularity of the belts around compression rollers 7 and 8.
As illustrated in FIGURE 2, roller 6 is mounted on swingarm 11 which is pivoted at 12, pivot 12 being attached to a supporting frame, not shown. Air cylinder 13 is pivotally attached to swingarm 11 and the supporting frame. Compressed air may be introduced at connection 14 to force piston 15 downwardly, thereby applying tension to belt 2. Similarly, air pressure may be applied at connection 16 to lift roller 6 to facilitate placement or removal of belt 2. A shock absorber 17 is also pivotally attached to swingarm 11 and the supporting frame as illustrated. In a similar fashion, roller 4 is mounted on swingarm 18 with attached air cylinder 19 and shock absorber 20.
Compression roller 8 is mounted on swingarm 21 which is pivotally supported at 22. Air cylinder 24 is pivotally attached to extension 23 of swingarm 21 and to the supporting frame. Compressed air may be applied to air cylinder 24 to move roller 8 toward fixed roller 7 and thus from a nip between belts 1 and 2 at this point. A shock absorber 25 is pivotally attached to swingarm 21 and the supporting frame.
In operation, the yarn or tow is fed from a source (not shown) over roller 26 and then into the nip formed by endless belts 1 and 2 which act to forward it downwardly into a rotating can 28 or other suitable container in a uniform fashion so that it can be easily withdrawn at a later time.
The roller diameters may be varied as desired but for most purposes rollers 3, 4, 5 and 6 may suitably be about 6 inches in diameter and rollers 7, 8, 9 and 10 about 4 inches in diameter. Drive rollers 3 and 5 are preferably geared together so that no speed differential exists between the two. The belt width may vary somewhat depending on the type of yarn or tow being processed but a 6-inch belt width is usually satisfactory for processing tow having a denier in the order of 100,000. The placement of the tension rollers relative to the drive rollers may be varied in accordance with other conditions but these rollers may suitably be placed about 30 inches apart, center to center.
While the type of belt may be selected to suit the par- The shock absorbers employed are conventional, com-- mercially available fluid-type shock absorbers. Double action shock absorbers having a 1.5-inch bore and a 4-inch stroke are suitable for tension rollers 4 and 6. Shock absorber 25 is preferably a single-action shock absorber of 1.5-inch bore and 3-inch stroke. This shock absorber is provided with a check valve which permits free flow of liquid when roller 8 is moved toward roller 7 but closes when the roller is moved in the reverse direction causing the fluid to be forced through the needle valve of the shock absorber, thus retarding movement in this direction only. Preferably, all of the shock absorbers are equipped with adjustable needle valves so that the retarding action may be adjusted as desired..
The nip formed by the belts should be relatively short,
although contact of the belt and tow may be maintained for some distance as the tow passes between rollers 7 and 8 due to slight expansion of the filament bundle as the pressure is relieved. After leaving rollers7 and 8, the belts gradually separate due'to the angularity of the belts relative to the vertical path oflthe tow. The angularity should be substantially the same for both belts to facilitate release of the tow from both belt surfaces and prevent wraps on the belts. The angle of the belt relative to the vertical path of the tow as the belt passes downwardly from the compression roll may suitably be about 0.5
The pressure on the air cylinders may be adjusted in accordance with other processing conditions; however, a
' pressure of 60 to 80 psi. is usually suitable for cylinder 24 while a pressureof 35 to 60 psi. may be employed for air cylinders 16 and 19.
The yarn delivery. device of this invention is useful in handling running yarn ends or tows of any material, synthetic or natural.
The apparatus of this invention provides continuous piddling of yarn or tow at speeds of 1,000 to 1,500 yards per minute under commercial conditions with freedom from formation of wraps on the belt and with a satisfactory laydown of the tow in the container. By contrast, when the prior art devices are operated at this speed, the action of the tow becomes erratic with the irregular laydown in the containerand. occasional loops falling over the edgeof the container. In addition, frequent wraps on the belt are encountered so that commercial ope-ration is impractical.
Several critical improvements contribute to the superior operability of the apparatus of this invention. The combination of air cylinder 24 .and shock absorber 25 cooperate to provide smooth running of the tow between compression rollers 7 and .8 While air cylinders 19 and 24 and shock absorbers 13 and 20 promote smooth running of the belts on the rollers.
Since many different embodiments of the invention may bemade without departing from the spirit and scope thereof, it is to be understood that the invention is not limited by the specific illustrations except to the extent defined in the following claims.
What is claimed is:
1. A yarn delivery apparatus for handling running lengths of yarn or tow at high speeds which comprises drive means, tension rollers vertically disposed from said drive means, two endless belts located in spatial proximity and mounted upon said drive means and tension rollers, an air cylinder and a double action shock absorber operably connected to each of said tension rollers to maintain said endless belts in a taut relationship and to absorb the shock created, a'pair of oppositely disposed compression rollers contacting said endless belts to form a short nip in said endless belts for gripping and advancing said yarn or tow, and an air cylinder and a single action shock absorber associated with at least one of said compression rollers to bias said compression rollers in maintaining said nip and to absorb the resultant shock, whereby the yarn or tow is vertically delivered with regular laydown.
2. The yarn delivery apparatus of claim 1 wherein said drive means are geared together in such a manner that the surface speed of said two endless belts is equal.
References Cited by the Examiner UNITED STATES PATENTS 1,917,659 7/1933 Marshall 198165 2,805,765 9/1957 Saum 226-172 2,858,936 11/1958 Ogden 198-208 3,046,771 7/1962 Bailey -198-l65 X M. HENSON WOOD, JR., Primary Examiner.
ROBERT B. REEVES, Examiner.
R. A. SCHACHER, Assistant Examiner.