Balloon control ring for a textile machine

A balloon control ring for a textile machine for limiting a circulating yarn balloon, wherein the balloon control ring comprising a metallic hollow cylinder with a wear-resistant surface, is characterised in that the hollow cylinder (2, 23, 37) is formed from a sheet metal strip, the hollow cylinder (2, 23, 37) is held by the end portions (3, 4; 14, 15; 38, 39) of the sheet metal strip, and an edge strip (8, 9; 10, 11; 55, 56) is folded round at the two edges of the hollow cylinder (2, 23, 37), with the sheet metal thickness of the sheet metal strip being at most 0.6 mm.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of German patent application 10 2005 062 261.5, filed Dec. 24, 2005, and corresponding International PCT Patent Application No. PCT/EP2006/010460, herein incorporated by reference.

BACKGROUND OF THE INVENTION

The invention relates to a balloon control ring for a textile machine for limiting a circulating yarn balloon, and more particularly wherein the balloon control ring comprises a metallic hollow cylinder with a wear-resistant surface.

So-called balloon control rings are used on two-for-one twisters and ply twisters in order to restrict the circulating yarn balloon formed by the running yarn. At winding machines, the balloon behavior of the yarn drawn from the cop is also influenced by means of the balloon control ring and the yarn tension is kept low.

The use of balloon control rings allows a reduction in the spacing designated the spindle gauge from spindle centre to spindle centre. In this manner, more spindles can be arranged at a textile machine without lengthening the machine.

German Patent Publication DE 1510869 A shows a balloon control ring, the cylindrical shell of which is formed by a ring. The holding takes place by means of solid filler elements which surround the balloon control ring on the entire periphery. The filler elements are in each case fastened to one of two longitudinal profile carriers extending spaced apart. This holding is expensive. The ring has folded over portions to secure its position, which prevent falling from the filler elements. Rings of this type are produced by forming methods such as extrusion or by welding.

It is known, for example, from German Patent Publication DE 2941160 A1, to produce the balloon control ring from formed aluminium or nickel chromium sheet metal. A hollow body produced by extrusion provides the running yarn with a disruption-free circulating path.

A straight bead-welded tube made of rolled sheet metal which is provided with a weld seam at the joint edge and is then pressure-rolled presents an economical finished hollow body for balloon control rings. Designs of this type require relatively thick sheet metal to ensure the stability of the balloon control ring. A sheet metal thickness of this type is also necessary for manufacturing reasons in order to be able to produce the balloon control ring as a deep-drawn part or in order to be able to lay a weld seam.

It is known from German Patent Publication DE 1510844 A to use wear-reducing special steels for balloon control rings, which special steels are however too heavy and too expensive. To avoid this drawback, it is proposed to form solid balloon control rings from aluminium alloys or balloon control rings from foils made of any material and to provide the inner surfaces of the balloon control rings with a chemically applied deposit of a phosphor alloy based on chromium as well as nickel, the hardness of which is at least equal to the hardness of a normal anodising layer of a balloon control ring made of an aluminium alloy. Balloon control rings which comprise foil strips made of metal or plastics material, however, have inadequate dimensional stability.

SUMMARY OF THE INVENTION

The object of the invention is to form a balloon control ring with a low weight, which comprises a wear-resistant metallic hollow cylinder and wherein a high degree of dimensional stability of the hollow cylinder is ensured.

This object is achieved in a balloon control ring for a textile machine for limiting a circulating yarn balloon, wherein the balloon control ring comprises a metallic hollow cylinder with a wear-resistant surface, by forming the hollow cylinder from a sheet metal strip, the end portions of which hold the hollow cylinder, and by providing an edge strip folded round at the two edges of the hollow cylinder. Optimally, the sheet metal thickness of the sheet metal strip is at most 0.6 mm.

To produce the balloon control ring according to the invention, only a small quantity of easily processed material is required. Despite the low weight, good dimensional stability is provided.

This stability can be achieved if an edge strip is folded round at the two edges of the hollow cylinder, in each case, the width of the fold is preferably between 5 mm and 10 mm. The sheet metal thickness of the sheet metal strip, from which the hollow cylinder is produced, is advantageously between 0.3 mm and 0.6 mm. This sheet metal thickness represents an optimum between a low weight and dimensional stability. A further increase in the stability of the cylindrical shape of the hollow cylinder can be achieved by end portions of the sheet metal strips bent round outwardly at right angles and pressed against one another. If the balloon control ring is formed in such a way that the end portions contact a frame wall of the textile machine and an electrically conductive connection is produced by the contact, the undesired electrostatic charge of the balloon control ring, which is produced by friction of the running yarn on the hollow cylinder, is discharged.

The balloon control ring is preferably held by means of a holding element which presses the end portions against one another. If the holding element in this case comprises first level contact faces, with which it abuts the end portions and presses these against one another, as well as at least a second concave contact face, with which it abuts the outer face of the cylinder, and if the balloon control ring is fixed by means of connecting elements which cross the holding element and the end portions, a hollow cylinder according to the invention is additionally stabilised. The second contact face, with which the holding element abuts the outer face of the hollow cylinder, is adapted to the curvature of the hollow cylinder.

The balloon control ring is provided with a secure seat in the holding element by means of free ends of the end portions, which are turned over in such a way that they engage behind the holding element.

Advantageously, the holding element has positioning cams and holding magnets, with which it can be fixed on a frame wall of the textile machine. The positioning cams of the holding element engage in corresponding positioning bores of the frame wall of the textile machine and allow rapid and exact positioning. The holding magnets which are rigidly connected to the holding element ensure, together with the positioning cams, a secure seat of the balloon control ring. The magnetic connection if necessary, can be detached easily and without the use of a tool. The holding element preferably consists of plastics material. A design of the holding element from plastics material has little weight. The holding element can be produced particularly economically from plastics material, for example as an injection moulding.

If the hollow cylinder consists of a thin stainless nickel chromium steel, the wear resistance is high even without an additional surface treatment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1,2and3show a balloon control ring1for a textile machine with a hollow cylinder2. The hollow cylinder2is formed from a sheet metal strip. The length of the sheet metal strip is greater than the periphery of the hollow cylinder2. An edge strip8,9is folded round, in each case, at the upper and lower edge of the hollow cylinder2. The edge strip8,9may have a width b of 5 mm to 10 mm. An end portion3,4is formed in each case from the longitudinal portion of the sheet metal strip extending beyond the periphery at each of the two ends of the sheet metal strip. The two end portions3,4are of equal length, bent outwardly at right angles and pressed against one another. The end portions3,4are pressed together by a rivet5and also rigidly connected to an angled lug6of the frame wall7of the textile machine. The hollow cylinder2is thus held in a simple manner by the end portions3,4of the sheet metal strip which are bent outwardly. The thin sheet metal strip may consist of a nickel chromium metal sheet or of an aluminium sheet, on which a wear-reducing surface treatment has been carried out.

The balloon control ring1is economical to produce and easy to fit. Additional holders are not required. The balloon control ring1is stable for the stress occurring from the circulating yam. The balloon control ring1shown in the embodiment is formed from a sheet metal strip made of nickel chromium sheet metal, which is 0.4 mm thick. During production of the balloon control ring1, the two edge strips8,9of the metal strip are firstly folded round and the cylindrical form of the hollow cylinder2is then formed with a three-roller machine by means of a rolling process, the surface contour of the rollers being adapted to the contour of the folds. The folded-round edge strip8,9ensures a high degree of stability of the balloon control ring1.

FIGS. 4,5and6show a balloon control ring12which is held by a two-piece holding element13. The balloon control ring12shown in the embodiment is formed from a sheet metal strip from nickel chromium sheet metal which is 0.4 mm thick. An edge strip10,11is folded round at the upper and lower edge of the balloon control ring12. The edge strip10,11may have a width b of 5 mm to 10 mm. The end portions14,15outwardly bent round at right angles are pressed against one another between the two part pieces18,19of the holding element13. The hollow cylinder23is held by the end portions14,15of the sheet metal strip. The part pieces18,19have continuous bores16,17which are flush with one another, through which in each case a connecting element configured as a screw connection20engages. A simple screw connection comprises, for example, a screw with a nut. The part pieces18,19in each case abut, with a first level contact face21,22, the end portions14,15. The pressing power by which the end portions14,15are pressed against one another is produced by tightening the screw connections20. The part pieces18,19of the holding elements13with a concave second contact face24,25, in each case, abut the hollow cylinder23. The curvature of the concave contact faces24,25is adapted to the curvature of the hollow cylinder23. The hollow cylinder23and the holding element13have the same height. The length, on which the concave contact face24,25abuts the outer periphery of the hollow cylinder23is represented in each case by the angle α. In the view ofFIG. 4, the angle α=30°. Alternatively, the design of the holding element13can be selected such that the angle α adopts a value of between 20° and 45°. Due to the concave contact faces24,25, the hollow cylinder23, over its entire height, finds support which stabilises the cylindrical shape of the hollow cylinder23.

A level third contact face26,27has two positioning cams28,29. The positioning cams28,29, to position the holding element, engage in bores30,31of the frame wall32. At least one holding magnet33,34is introduced into the contact faces26,27, in each case. The holding magnets33,34adhere to the frame wall32and ensure a secure seat of the holding element13. The holding element13is an injection moulding made of plastics material.

The end portions14,15project slightly over the third contact faces26,27of the holding element13as shown enlarged for clarity inFIG. 6. This projection designated a is very small and is, for example, 0.1 mm. When the balloon control ring12is positioned on the frame wall32, the projection a of the end portions14,15ensures that the end portions14,15are in contact with the frame wall32and an electrically conductive connection is produced between the hollow cylinder23, and frame wall32. By means of this electrically conductive connection, the electrostatic charge, which is produced by the friction of the circulating yarn in the hollow cylinder23, is reliably discharged. An electrostatic charge is undesired as it encourages the disruptive depositing of dust and fibre fly on the inside of the hollow cylinder23.

FIGS. 7 and 8show a balloon control ring35with a one-piece holding element36. An edge strip55,56is folded round in each case at the upper and lower edge of the balloon control ring35. The edge strip55,56may have a width b of 5 mm to 10 mm. The end portions38,39bent round outwardly at right angles from the hollow cylinder37are inserted through the rectangular opening40, which crosses the holding element36. The holding element36has continuous bores41,42extending transversely to the end portions38,39. The screw connections43,44engage through the bores41,42. By tightening the screw connections43,44, a pressing power is produced by the level contact faces46of the holding element36and presses the end portions38,39against one another. The holding element36, with the concave contact face45abuts the hollow cylinder37and thereby stabilises the cylindrical form of the hollow cylinder37. The curvature of the concave contact face45is adapted to the curvature of the hollow cylinder37. The length of the end portions38,39is greater than the depth of the opening40. Once the end portions38,39have been inserted through the opening40, the ends47,48therefore project beyond the holding element36. The projecting free ends47,48are then turned over. The turned over free ends47,48then lie in a trough49of the holding element36. The turning over of the ends47,48brings about a secure seat of the hollow cylinder37on the holding element36and stabilises the balloon control ring35. A level contact face50of the holding element36remote from the hollow cylinder37has two positioning cams51,52. The positioning cams51,52engage, to position the holding element36, in bores of the frame wall32of the textile machine. Two holding magnets53,54are introduced into the level contact face50of the holding element36. The holding magnets53,54adhere on the frame wall32and ensure a reliable fixing of the holding element36. The holding element36, like the holding13shown inFIG. 4, is an injection moulding made of plastics material.

When the holding element36is fixed by means of the holding magnets53,54on the frame wall32, the turned over free ends47,48contact the frame wall32, as shown enlarged for clarity inFIG. 9. As a result, an electrically conductive connection, which prevents an electrostatic charge of the hollow cylinder37, exists between the hollow cylinder37and the frame wall32.