US3499615A - Snag shield for magnetic torque yarn tension device - Google Patents

Description

March 10, 1910 AQCk 'KIR CHER .'3',499.6

SNAG SHIELD FOR MAGNETIC TORQUE YARN TENSION DEVICE.

' Filed NwLs. 1967 l8 l I all INVENTOR lo AUGUST C. K/RCHER BV J 67M ATTORNEY United States Patent 3,499,615 SNAG SHIELD FOR MAGNETIC TORQUE YARN TENSION DEVICE August C. Kircher, Farmington, Conn., assignor to Allied Control Company, Incorporated, New York, N.Y., a corporation of New York Filed Nov. 8, 1967, Ser. No. 681,477 Int. Cl. B65h 59/16, 57/00 U.S. Cl. 242-155 5 Claims ABSTRACT OF THE DISCLOSURE An inverted cone-shaped yarn snag shield is suspended below the rotatable capstan of a magnetic torque yarn tension device to prevent yarn loops from snagging or becoming entangled on the base plate or supporting frame of the device. The base of the shield is substantially coterminous with the capstan such that the conical surface of the shield extends to and is flush with the periphery of the capstan. The apex of the cone-shaped shield is displaced to the rear (toward the. mounting frame) of the line of suspension of anyyarn loop that may form so that the yarn will ride-up the conical surface of the shield and be repositioned automatically to its proper running position about the peripheryof the capstan in response to tension being applied to the yarn when movement of the yarn is initiated. a

FIELD OF THE INVENTION This invention relates to yarn tension devices used in the textile industry to control the tension of traveling yarns. More particularly, this invention relates to a snag shield for such a device to prevent snagging or entanglement of yarn loops on the base or supporting frame of the device and to reposition automatically the yarn to the proper running position on the device when movement of the yarn is initiated.

BACKGROUND OF THE INVENTION Tension devices are used extensively in the textile industry to maintain traveling yarns under controlled tension. For example, in the beaming of a warp, hundreds of yarn packages or spools are mounted in a creel and simultaneously drawn to the spool of a beaming machine. Unless the tension of all the yarns is substantially uniform, a defective warp can result when looser yarns pile up and overlap tighter yarns. Accordingly, an individual tension device is utilized to control the tension of each yarn involved in a beaming Operation.

One type of tension device called an electromagnetic whor or magnetic torque yarn tension device has been found to be particularly advantageous by the textile industry because hundreds of the devices can be electrically controlled by a single simple adjustment to select a desired tension for a large number of traveling yarns. Such devices are described, for example, in U.S. Patents Nos. 2,705,362 and 2,738,937, which issued to R. H. Roughsedge on Apr. 5, 1955 and Mar. 20, 1956, respectively, and in U.S. Patent No. 3,034,744, which issued to J. E. Bancroft on May 15, 1962.

In the tension devices described in the above patents, the traveling yarn is fed through an inlet yarn guide, passed around the periphery of a rotatable wheel or capstan, and fed out through an outlet yarn guide. The yarn is trained about the capstan in a manner to cause the capstan to rotate in response to the travel of the yarn. A drag, or braking force, is applied to the capstan by magnetic or electromagnetic means, which results in tension being applied to the traveling yarn.

3,499,615 Patented Mar. 10, 1970 Although tension devices of the type described above have been used extensively by the textile industry for years, one difliculty With the device continues to plague the industry. This difficulty is caused by the yarn loops occasionally formed when an operative condition known as overrun occurs. Overrun is a condition where the capstan continues to turn for a short interval after the take-up spool for the traveling yarn is halted (i.e., the beaming operation is stopped). This condition can result from an improper amount and/or improper timing of the control voltage applied to the tension device during start up or shutdown of a textile operation. The overrun condition can also result from improper handling of the yarn by anoperator (i.e., jerking of the yarn during threading) while the textile operation is halted. The overrun condition causes the yarn to become disengaged from the periphery of the capstan and to extend in a loop below the mounting plate or frame which supports the rotatable capstan.

These yarn loops are the cause of considerable difliculty in that they frequently snag on the frame or base supporting the tension device and cause the yarn to break when the textile operation is resumed. Alternatively, the yarn will continue to run in the snagged condition resulting in an excessive tension being applied to the yarn. Furthermore, when the yarn continues to run in the snagged condition, it is subjected to scoring or abrasion by the rough yarn contact area and frequently is discolored by the metal removed from the frame or base upon which the yarn is snagged.

To cope with the difiiculties described above, it is now necessary to make a visual inspection of each tension device involved in a textile operation prior to initiation of the operation to determine that each yarn is properly positioned on its tension device and that no yarn loops are present. It will readily be appreciated that this is time consuming and costly because as many as 1200 to 1400 tension devices may be utilized on a single machine. Furthermore, this inspection must be repeated each time the textile operation is halted, and hence significantly increases the down-time of the operation. This, of course, results in increased costs. In the event that a yarn loop of the type described above is detected, the operator must remove the excess yarn causing the loop and reposition the yarn to its proper running position around the periphery of the capstan. Thus, each yarn must be handled individually by the operator, which further increases the down-time of the operation.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-described difficulties experienced with magnetic torque yarn tension devices.

It is a specific object of the invention to prevent yarn loops from snagging or becoming entangled on the base or framework supporting a yarn tension device of the type described above when movement of the yarn is initiated.

It is a further specific object of the invention to reposition automatically the yarn suspended in a loop to the correct running position about the periphery of the capstan of a yarn tension device of the type indicated above in response to movement of the yarn.

The foregoing and other objects are attained in an illustrative embodiment of the invention which comprises an inverted cone-shaped shield suspended below the rotatable capstan of a yarn tension device of the type described above. The base of the shield is substantially coterminous with the capstan such that the conical surface of the shield extends from its apex to and is substantially flush with the periphery of the capstan. The axis of the conical shield is at an angle with respect to the capstan (viz, the base of the cone) such that the apex of the cone-shaped shield is displaced to the rear (toward the supportingframe of the tension device) of the line of suspension of any yarn loop that may form.

A yarn loop caused by the overrun condition described above or by improper y'arn handling is, in and of itself, harmless and causes difliculties only when it snags or becomes entangled on the supporting frame of the yarn tension device. Thus, in accordance with an aspect of the present invention, yarn loops are prevented from snagging or becoming entangled on the base or framework supporting the tension device by the coneshaped shield, and any yarn loop which does form remains harmless.

In accordance with another important feature of the present invention, not only is a yarn loop prevented from snagging on the base of the tension device, but concomitantly in response to travel of the yarn, the yarn loop is eliminated and the yarn is automatically repositioned to the proper running position about the periphery of the capstan of the tension device. The displacement of the apex of the cone-shaped shield to the rear of the line of suspension of any yarn loop that forms ensures that the yarn will not locate itself on the back (toward mounting frame) of the cone-shaped shield, but instead of rideup the front (away from mounting frame) of the conical surface of the shield and onto the periphery of the capstan of the device when tension is applied as a result of movement of the yarn.

Advantageously, the provision of shields in accordance with the present invention on magnetic torque yarn tension devices of the type indicated above eliminates the need for a visual inspection of each of the devices for possible yarn loops each time a textile operation is halted, and also eliminates the need for individual handling of each yarn that may have formed into a yarn loop.

DESCRIPTION OF THE DRAWING The foregoing and other objects and features of the present invention will be more readily understood from the following detailed description of an illustrative embodiment thereof when read with reference to the accompanying drawing in which:

FIG. 1 is a perspective view of a magnetic torque yarn tension device of the type described above, on which has been installed a yarn snag shield in accordance with the principles of the invention and shows a typical yarn loop suspended from the device;

FIG. 2 is the same perspective view as FIG. 1 but shows the manner in which the yarn loop is eliminated and the manner in which the yarn rides-up the conical surface of the snag shield of this invention in response to tension applied to the yarn when movement of the yarn is initiated; and

FIG. 3 is the same perspective view as FIGS. 1 and 2 but shows the manner in which the yarn is repositioned to the proper running position about the periphery of the rotatable capstan of the yarn tension device by the yarn snag shield of the invention.

DETAILED DESCRIPTION An illustrative embodiment of a yarn snag shield 10 in accordance with the principles of the invention is shown in FIGS. 1 through 3 of the drawing suspended below base plate 11 of a magnetic torque yarn tension device 12. Tension device 12 may be a tension device of the type described in the above-identified United States patents of R. H. Roughsedge or J. E. Bancroft, or may be any device having a rotatable wheel or capstan such as capstan 13 of tension device 12 about which a yarn to be controlled is positioned.

As shown in the drawing, tension device 12 is secured to mounting rod 14 by bracket 15 and screw 16. Capstan 13 has a central shaft 17 about which it rotates. Shaft 17 is supported on suitable bearings (not shown) on base plate 11. Concentric with shaft 17 and secured to base plate 11 inside capstan 13 is-an electrornagnetic field member (not visible in drawing) which produces the magnetic flux that interacts with a rotor concentrically mounted on the inner surface of capstan 13, and thus not visible in the drawing, to produce a drag, or braking force, opposing rotation of capstan 13.

Yarn 18, the tension of which is to be controlled, is threaded through an inlet yarn guide 19, passed around the periphery of capstan 13 in a clockwise direction, and threaded out through an outlet yarn guide 20 in a direction from right to left as shown in the. drawing. When yarn 18 is in its proper running position. aroundcapstan 13, it follows the dotted path 18' shown in FIG. 1. However, when an overrun condition occurs, as described above, or when yarn 18,is improperly handled, it may form in a loop 18" suspended from tension device 12 as shown in FIG. 1. i

As shown in the drawing, snag shield 10, in accordance with the present invention, is an inverted coneshaped member suspended below base plate 11 and is substantially coterminous therewith at its base. Shield 10 may be fabricated of any suitable material, such as plastic or metal, and secured to base plate 11 ina manner well known in the art. The surface of shield'10 extends from the apex 10 to and is substantially flush with the surface of base plate 11, which in turn is flush with the periphery of capstan 13, thus providing an uninterrupted path for yarn loops such as 18" to traverse when sliding up the conical surface of shield 10 onto the periphery of capstan 13.

As illustrated in the drawing, capstan 13 is positioned in a cylindrical cavity in base plate 11 and thus shield 10 is made coterminous with base plate 11 to provide the uninterrupted path for the yarn loop 18 to traverse. In some types of yarn tension devices, the capstan is not positioned in a depression and, accordingly, in accordance with the principles of the present invention, shield 10 would be coterminous with the capstan and extend to be substantially flush with the periphery of the capstan. I

Yarn shield 10 is not a right-circular cone, as the apex of shield 10 is offset or displaced to the rear as viewed in the drawing, such that it is located behind the line of suspension of any yarn loop 18" that may form in yarn '18. This will prevent such yarn loops from locating behind the conical shield 10 when tension is applied to yarn 18 in response to movement of the yarn. Thus, shield 10 prevents yarn 18 from snagging on the lower side of base plate 11 when yarn movement is initiated.

FIGS. 2 and 3 illustrate the manner in which shield 10 automatically guides yarn 18, which has formed into a loop 18" to the proper running position around the periphery of capstan 13. As shown in FIG. 2, when movement of the left-hand end of yarn 18 is initiated, the slack yarn forming loop 18 is taken up and loop 18" rides up the surface of shield 10. As further slack in loop 18" is removed, loop 18" becomes smaller, and finally yarn 18 clears shield 10 on base plate 11 in the manner shown in FIG. 3. When all of the slack forming loop 18" is removed, yarn 18 will once again be positioned about the periphery of capstan 13 as illustrated by dotted line 18' in FIG. 1.

In the manner described above and illustrated in the drawing, shield 10 not only prevents a yarn loop from snagging on base plate 11, but also automatically repositions yarn 18 to the proper running position around the periphery ofcapstan 13 when movement of the yarn is initiated.

It is to be understood that the above-described embodiment is illustrative only of the principles of the present invention. Numerous other arrangements may be devised by those skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. In a yarn tension device comprising a support member, a capstan mounted on said support member for rotation about a vertical axis in response to longitudinal movement of a yarn trained about the periphery thereof and means for applying a force to said capstan to resist said rotation and thereby impart tension to said yarn, the invention comprising a yarn snag shield comprising an inverted cone-shaped member suspended below said capstan with the base of said member substantially coterminous with at least a portion of said capstan to prevent a yarn loop suspended from said tension device from snagging on said support member, said shield further including means for automatically repositioning said yarn loop to a position trained about the periphery of said capstan in response to the initiation of longitudinal movement of said yarn, said means for repositioning said yarn loop comprising the conical surface of said member.

2. The yarn snag shield defined in claim 1 wherein the apex of said inverted cone-shaped member is displaced to the rear of the line of suspension of said yarn loop suspended from said tension device whereby said yarn loop will ride-up the conical surface of said member and onto the periphery of said capstan in response to the initiation of longitudinal movement of said yarn.

3. In combination with a yarn tension device for controlling the tension of a moving yarn, means for preventing a yarn loop suspended from said device from snagging on the structure supporting said device and concomitantly automatically positioning said yarn loop to the correct running position on said device in response to the initiation of movement of said yarn, said tension device comprising:

a base plate,

a capstan positioned in a cylindrical cavity in the upper surface of said base plate and extending upwardly therefrom,

said yarn being trained about the periphery of the portion of said capstan extended above said base plate whereby said capstan rotates about a vertical axis in response to movement of said yarn,

and wherein said means for preventing a yarn loop from snagging and concomitantly automatically positioning said yarn loop comprises:

a yarn snag shield afiixed to the lower surface of said base plate and extending downwardly therefrom, said shield being substantially coterminous with said base plate.

4. The combination defined in claim 3 wherein said yarn snag shield comprises an inverted cone-shaped member affixed to the lower surface of said base plate, with the base of said cone-shaped member being substantially coterminous with said base plate and with the apex of said member extending downwardly.

5. The combination defined in claim 4 wherein said apex of said cone-shaped member is oifset behind the line of suspension of said yarn loop suspended from said tension device whereby said yarn loop will ride-up the conical surface of said member and onto the periphery 5/1888 Cumming 2421S5 5/ 1962 Bancroft.

STANLEY N. GILREATH, Primary Examiner

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