YARN TENSIONING DEVICE

Abstract: A yarn tensioning device (10) having a yarn tensioning element mounted on a seat (16) within a housing (11) through which the yarn travels. A cap (25) is mounted in the outlet of the housing and has a smaller opening than the size of the tensioning elements (34) to prevent replacement or addition of elements and is secured in the housing to prevent removal. The cap has a tapered inner surface (28) and two sequential frusto-conical outer surfaces (29) forming a juncture therebetween. The annular peripheral surface (33) of the cap is relieved. The tensioning element (34) is elongated and shaped to preclude rotation during operation and particularly when yarn travel stops during operation of the associated equipment.

Description: The present invention relates to a yarn tensioning device comprising a housing having a yarn inlet and a yarn outlet for travel of yarn through said housing, said housing having an annular seat formed in the yarn inlet, a yarn tensioning element in said housing engagable on said seat for applying tension to a yarn traveling between the seat and the tensioning element and a cap mounted in said yarn outlet and having a yarn passageway therethrough. Yarn tensioning devices of this type, such as disclosed and claimed in my prior U.S. Patents RE.30,920, RE.31,024 and RE.31,041 have proven to be highly successful in providing reliable uniform tensioning of yarn in various types of yarn and thread processing equipment, such as in textile winders, warpers, weaving looms, knitting machines and the like and in other types of equipment in textile and other fields that involve processing or handling of traveling strand material. Previous devices of this general type have been provided with removable caps or retaining elements that allow removal and replacement of the tensioning elements, which has been considered advantageous in allowing the change of elements for operation with yarns of different size or running characteristics. However, this has led to improper substitution and addition of elements with resulting non-uniform and/or imperfect tensioning. When using a cap on the housing of a tensioning device of this type such as disclosed in US-Patent 4 030 684 and terminating in a radial shoulder, it is sometimes difficult to initially thread the yarn through the housing and cap as a threading rod may be obstructed by the inner surface of the cap and threading by air can also be disrupted by the shape of the inner surface of the cap. This is particularly a problem where the cap is formed with a small passageway for the purpose mentioned above of preventing removal or insertion of tensioning elements. It was also known as disclosed in DE-U-8115620 to arrange a yarn tensioning device at the entrance of a hollow two-for-one twisting spindle. This yarn tensioning device has two frusto-conical annular seats formed by two rings which are engagable by two tensioning elements. For pneumatic threading of a yarn the tensioning elements are manually moved aside. It is the object of the present invention to alleviate the problem of threading and to provide improved handling of the yarn. This object is achieved by said cap being formed with the frusto-conical inner annular surface tapering from said housing to said passageway and in that said cap has an outer annular surface extending from said passageway, said outer surface being formed with two sequentially adjacent frusto-conical surface portions of progressively greater taper forming a yarn contacting annular juncture therebetween. By the frusto-conical inner annular surface tapering from the housing to the passageway, a threading rod will be guided along the surface into the passageway and an air threading blast will also be directed toward the passageway. The frusto-conical inner annular surface of the cap further can provide enhanced yarn behaviour in certain yarns as the yarns pass through the device and contact this inner annular surface. Enhanced behaviour of some yarn is also obtained by the feature that the cap is formed with two sequentially adjacent frusto-conical surface portions of progressively greater taper forming a yarn contacting annular juncture therebetween. Thus, as the yarn passes over the surface and contacts this juncture, improved behaviour of the yarn is obtained, particularly with high torque yarn where this action results in a relaxation of the yarn. Improved handling of the yarn is further facilitated by another feature of the present invention wherein the cap is formed with a relieved peripheral outer annular surface that eliminates yarn contact with an otherwise sharp outer edge of the cap. The problem of improper substitution and addition of elements with resulting non-uniform and/or imperfect tensioning is overcome by the further improvement of the present invention according to which said cap is fixed against removal in the yarn outlet and has its yarn passageway therethrough smaller than said tensioning element to prevent removal or replacement of said tensioning element. In this regard, it has been determined that a selected size of tensioning element is normally suitable for use with a wide range of yarn types and characteristics and with a wide range of types of equipment, such that changing of tensioning elements or removing or adding elements is not necessary, and when such changes are made, it can result in problems when not done with expertise in selection of the elements to be used. Brief Description of the Drawings Fig. 1 is a side elevation of a yarn tensioning device according to the preferred embodiment of the present invention; Fig. 2 is a vertical sectional view of the yarn tensioning device of Fig. 1; Fig. 3 is an enlarged vertical sectional view of the cap of the yarn tensioning device of Fig. 1; Fig. 4 is a view similar to Fig. 2 showing a different type of tensioning element in the yarn tensioning device; Fig. 5 is a view similar to Fig. 2 showing a conventional cap and retaining element; and Fig. 6 is a view similar to Fig. 5 showing a different type of yarn tensioning element within the device. Detailed Description of the Preferred Embodiments Referring first to Figs. 1, 2 and 3, a yarn tensioning device 10 according to a preferred embodiment of the present invention is shown having a generally cylindrical housing 11 formed with a yarn inlet 12 and a yarn outlet 13. Mounted in the inlet 12 is an insert 14 having a central yarn passage 15 extending therethrough and a seat 16 formed at the inner end of the yarn passage 15 within the housing 11. A yarn tensioning element 17 (Fig. 4) is contained within the housing 11 and engages on the seat 16 of the insert 14 for applying tensioning weight to a yarn traveling through the housing 11 and between the insert seat 16 and tensioning element 17. The housing 11 is formed with an enlarged end 18 at the outlet 13. This enlarged end 18 forms an annular flange 19 defining an annular recess 20 therewithin. The device 10 is mounted on a convenient structure in relation to the equipment with which the device is being used by the use of a mounting bracket 21 having a cylindrical portion 22 surrounding the housing 11 and abutting the enlarged end 18. The mounting bracket 21 has a flat plate- like projection 23 extending from the cylindrical portion 22 and having a slot 24 formed therein through which a mounting element can be inserted for mounting of the bracket 21 and attached tensioning device 10 to the desired supporting structure. Mounted in the yarn outlet 13 of the housing 11 is a cap 25 that is fixed against removal from the housing 11 and has a generally cylindrical yarn passageway therethrough, which is smaller than the tensioning element 17 to prevent removal or replacement of the tensioning element. The cap 25 has an annular shoulder that is inserted in the aforementioned housing recess 20, with the shoulder 27 being inclined outwardly into the recess 20 for substantially non-removable seating therein. The outward inclination of the shoulder 27 is preferably at an angle of approximately 4 degrees. With this arrangement, particularly when the components are made of plastic material, and dimensioned for tight fit, once the shoulder 27 of the cap 25 is inserted in the housing recess 20, it is substantially impossible to remove the cap, thus assuring that the tensioning element 17 initially selected for proper operation cannot be changed thereafter. Therefore, an inexperienced or inattentive operator cannot change the size or form of tensioning element or add additional elements, which could change the performance of the device. In this regard, it has been discovered that a selected size or shape of tensioning element is capable of substantially optimum tensioning application over a relatively wide range of yarn sizes and characteristics and in a variety of equipment. As illustrated in Figs. 1-4, and as best seen in the enlargement of Fig. 3, the cap 25 is formed with a frusto-conical inner annular surface 28 tapering from the housing 11 to the cylindrical yarn passageway 26. Preferably, the frusto-conical inner surface 28 tapes at an angle of approximately 30 degrees to a vertical center line through the device. This conical configuration and the relatively small taper facilitates the initial threading of yarn through the device when using a threading rod which will be easily deflected along the conical surface 28 into and through the yarn passageway 26. Also, the gentle taper also facilitates the direction of air to and through the yarn passageway 26 when threading with an air device. In addition, the conical shape can provide improved yarn behavior during tensioning. For example, when running high torque yarn this surface can provide a relaxing of the twist. This is a particular advantage during warping of open-end yarn and during intermittent non-uniform motion that is characteristic of weaving. This frusto-conical shape does not provide an advantage in all applications, but it does provide a significant advantage in selected applications, and it has not been found to be disadvantageous in any application. As further illustrated in Figs. 1-4, and particularly in the enlargement of Fig. 3, the cap 25 has an outer annular surface 29 extending from the yarn passageway 26. This outer surface is formed with two sequentially adjacent frusto-conical surface portions 30 and 31 of progressively greater taper forming a yarn contacting annular juncture 32 therebetween. Preferably the taper of the inner portion 30 is approximately 30 degrees from the general center line of the device and the taper of the outer portion 31 is approximately 60 degrees from the general center line of the device. This double taper with a distinct annular juncture therebetween has been found to be advantageous in reducing friction of the yarn running over the surface of the cap, particularly in comparison with a generally round surface, which, with some types of yarn causes undesirable spreading. By eliminating the rolling or rotating of the tensioning element, the tensioning element will drop quickly against the seat stopping the yarn travel quicker than when a spherical element rolls onto the seat. For example, fiberglass and open (non-twisted) filament yarn tend to spread on a curved surface of a tensioning device whereas with the double angled and junctured surfaces of the present invention, friction is reduced and spreading is minimized. To further facilitate uniform, smooth handling of yarn traveling through the device 10, the cap 25 is formed with a relieved peripheral outer annular surface 33, which is preferably relieved at an angle of approximately 30 degrees. This avoids undesirable sharp contact with a yarn that is guided in a direction that results in some contact with the outer peripheral edge of the cap 25. As illustrated in Fig. 4, the above-described cap 25 can be used in a device 10 that contains a conventional spherical tensioning element 17. However, enhanced results have been obtained with some types of yarn and with some types of equipment by using, according to the present invention, a tensioning element 34 (Figs. 1, 2 and 5) or 35 (Fig. 6), that is sufficiently non-spherical to preclude substantial rotation of the element during traveling of the yarn therepast. In some applications with some types of yarn, a free-rolling spherical element has the disadvantage of creating yarn picks and winding of the yarn on the element when the yarn travel is stopped during the intermittent action of the equipment. This is particularly a problem in quick stopping of high speed operations, such as with shuttleless loom weaving or high speed warping. Open filament yarn and fine filament yarns are particularly susceptible to this problem. In some applications, this is not a problem, such as in most winding operations, but as indicated there are selected applications where this feature is advantageous. Preferably, the yarn tensioning elements 34,35 are elongated in a direction away from the seat 16 so as to be maintained in position in the housing 11, and they have partially spherical surface portions 36 that are engagable on the seat 16 for uniform yarn engagement around the circumference of the seat 16. In the form of the tensioning element 34 illustrated in Figs. 1, 2 and 5, the tensioning element 34 is in the form of two spherical elements 37 and 38 secured together as at 39 by welding or other securing means. In this form, the tensioning element 34 can easily be manufactured from existing spherical elements and can be a combination of different size individual elements, such as using a larger element on top, which can be an advantage in some applications where additional weight is desired. In this manner the bottom spherical component can shift on the seat while the top component remains somewhat stationary and applies uniform weight. Also, a small spherical component at the bottom permits deeper seating with greater friction than is the case with a larger component at the bottom. An alternate form of yarn tensioning element 35 is illustrated in Fig. 6, where the element is seen to have semi-spherical portions 36 at both ends and a cylindrical center portion 40 therebetween. In this form the tensioning element 35 would be specially formed rather than combined from existing spherical components, but having semi-spherical end portions 36 allows the tensioning element 35 to be inserted with either end at the seat 16. It is apparent that the foregoing individual features of the present invention are preferably used in combination, but they may also be used individually or in sub-combinations to advantage in particular applications, as will be recognized by one skilled in the art. As illustrated in Figs. 5 and 6, the tensioning element of the present invention in the forms of the secured spherical elements 37,38 and in the form of the element 35 with the cylindrical center portion 40, may be incorporated in an otherwise conventional yarn tensioning device 41 having similar housing 42, insert 43 and mounting bracket 44 elements as described with regard to the embodiments of Figs. 1-4, but with the housing 42 being conventionally constructed with a side projection 45 in which a tensioning element retaining finger 46 is positioned for pivoting into and out of position above the housing 42 to retain the tensioning element 35 within the housing 42 during operation and movable out of position to allow removal or replacement of the tensioning element 35. Also, in the form of Figs. 5 and 6, a conventional cap 47 is used without the features described above for the cap 25 of the embodiments of Figs. 1-4. It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of a broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiment, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto.

Claims: A yarn tensioning device comprising a housing (11) having a yarn inlet (12) and a yarn outlet (13) for travel of yarn through said housing, said housing having an annular seat (16) formed in said yarn inlet, a yarn tensioning element (17,34,35) in said housing engagable on said seat for applying tension to a yarn traveling between said seat and said tensioning element and a cap (25) mounted in said yarn outlet (13) and having a yarn passageway (26) therethrough, characterized by said cap (25) being formed with a frusto-conical inner annular surface (28) tapering from said housing (11) to said passageway (26) and in that said cap has an outer annular surface (29) extending from said passageway (26), said outer surface being formed with two sequentially adjacent frusto-conical surface portions (30, 31) of progressively greater taper forming a yarn contacting annular juncture (12) therebetween. A yarn tensioning device according to claim 1 and characterized further in that said frusto-conical inner surface (28) tapers at an angle of approximately 30°. A yarn tensioning device according to claim 1 and characterized further in that the tapers of said surface portions (30, 31) being approximately 30° and 60°. A yarn tensioning device according to anyone of the claims 1 to 3 and characterized further in that said cap (25) is formed with a relieved peripheral outer annular surface (33). A yarn tensioning device according to claim 4 and characterized further in that the relief of said peripheral surface (33) is approximately 30°. A yarn tensioning device according to anyone of claims 1 to 5 and characterized further in that said cap (25) is fixed against removal in the yarn outlet and has its yarn passageway (26) therethrough smaller than said tensioning element (17,34, 35) to prevent removal or replacement of said tensioning element.

Inventors: ZOLLINGER, OTTO
Applicants: OTTO ZOLLINGER, INC.
Application year: 1989
Main classification: B65H59
IPC codes: B65H59