Abstract:
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.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    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 
       [0002]    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. 
         [0003]    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. 
         [0004]    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. 
         [0005]    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. 
         [0006]    It 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. 
         [0007]    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. 
         [0008]    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 
       [0009]    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. 
         [0010]    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. 
         [0011]    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. 
         [0012]    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. 
         [0013]    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. 
         [0014]    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. 
         [0015]    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. 
         [0016]    If the hollow cylinder consists of a thin stainless nickel chromium steel, the wear resistance is high even without an additional surface treatment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0017]    Further details of the invention can be inferred from the embodiments described with the aid of the figures, in which: 
           [0018]      FIG. 1  shows a sectional plan view of a balloon control ring, 
           [0019]      FIG. 2  shows a lateral view of the balloon control ring of  FIG. 1 , 
           [0020]      FIG. 3  shows a front view of the balloon control ring of  FIG. 1 , partially in section, 
           [0021]      FIG. 4  shows a balloon control ring with a two-piece holding element along the section B-B in plan view, 
           [0022]      FIG. 5  shows the balloon control ring of  FIG. 4  in the view A, 
           [0023]      FIG. 6  shows the detail Y from  FIG. 4 , 
           [0024]      FIG. 7  shows a balloon control ring with a one-piece holding element along the section D-D in a plan view, 
           [0025]      FIG. 8  shows the balloon control ring of  FIG. 7  in the view C, 
           [0026]      FIG. 9  shows the detail X from  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]      FIGS. 1 ,  2  and  3  show a balloon control ring  1  for a textile machine with a hollow cylinder  2 . The hollow cylinder  2  is formed from a sheet metal strip. The length of the sheet metal strip is greater than the periphery of the hollow cylinder  2 . An edge strip  8 ,  9  is folded round, in each case, at the upper and lower edge of the hollow cylinder  2 . The edge strip  8 ,  9  may have a width b of 5 mm to 10 mm. An end portion  3 ,  4  is 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 portions  3 ,  4  are of equal length, bent outwardly at right angles and pressed against one another. The end portions  3 ,  4  are pressed together by a rivet  5  and also rigidly connected to an angled lug  6  of the frame wall  7  of the textile machine. The hollow cylinder  2  is thus held in a simple manner by the end portions  3 ,  4  of 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. 
         [0028]    The balloon control ring  1  is economical to produce and easy to fit. Additional holders are not required. The balloon control ring  1  is stable for the stress occurring from the circulating yam. The balloon control ring  1  shown 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 ring  1 , the two edge strips  8 ,  9  of the metal strip are firstly folded round and the cylindrical form of the hollow cylinder  2  is 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 strip  8 ,  9  ensures a high degree of stability of the balloon control ring  1 . 
         [0029]      FIGS. 4 ,  5  and  6  show a balloon control ring  12  which is held by a two-piece holding element  13 . The balloon control ring  12  shown in the embodiment is formed from a sheet metal strip from nickel chromium sheet metal which is 0.4 mm thick. An edge strip  10 ,  11  is folded round at the upper and lower edge of the balloon control ring  12 . The edge strip  10 ,  11  may have a width b of 5 mm to 10 mm. The end portions  14 ,  15  outwardly bent round at right angles are pressed against one another between the two part pieces  18 ,  19  of the holding element  13 . The hollow cylinder  23  is held by the end portions  14 ,  15  of the sheet metal strip. The part pieces  18 ,  19  have continuous bores  16 ,  17  which are flush with one another, through which in each case a connecting element configured as a screw connection  20  engages. A simple screw connection comprises, for example, a screw with a nut. The part pieces  18 ,  19  in each case abut, with a first level contact face  21 ,  22 , the end portions  14 ,  15 . The pressing power by which the end portions  14 ,  15  are pressed against one another is produced by tightening the screw connections  20 . The part pieces  18 ,  19  of the holding elements  13  with a concave second contact face  24 ,  25 , in each case, abut the hollow cylinder  23 . The curvature of the concave contact faces  24 ,  25  is adapted to the curvature of the hollow cylinder  23 . The hollow cylinder  23  and the holding element  13  have the same height. The length, on which the concave contact face  24 ,  25  abuts the outer periphery of the hollow cylinder  23  is represented in each case by the angle α. In the view of  FIG. 4 , the angle α=30°. Alternatively, the design of the holding element  13  can be selected such that the angle α adopts a value of between 20° and 45°. Due to the concave contact faces  24 ,  25 , the hollow cylinder  23 , over its entire height, finds support which stabilises the cylindrical shape of the hollow cylinder  23 . 
         [0030]    A level third contact face  26 ,  27  has two positioning cams  28 ,  29 . The positioning cams  28 ,  29 , to position the holding element, engage in bores  30 ,  31  of the frame wall  32 . At least one holding magnet  33 ,  34  is introduced into the contact faces  26 ,  27 , in each case. The holding magnets  33 ,  34  adhere to the frame wall  32  and ensure a secure seat of the holding element  13 . The holding element  13  is an injection moulding made of plastics material. 
         [0031]    The end portions  14 ,  15  project slightly over the third contact faces  26 ,  27  of the holding element  13  as shown enlarged for clarity in  FIG. 6 . This projection designated a is very small and is, for example, 0.1 mm. When the balloon control ring  12  is positioned on the frame wall  32 , the projection a of the end portions  14 ,  15  ensures that the end portions  14 ,  15  are in contact with the frame wall  32  and an electrically conductive connection is produced between the hollow cylinder  23 , and frame wall  32 . By means of this electrically conductive connection, the electrostatic charge, which is produced by the friction of the circulating yarn in the hollow cylinder  23 , 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 cylinder  23 . 
         [0032]      FIGS. 7 and 8  show a balloon control ring  35  with a one-piece holding element  36 . An edge strip  55 ,  56  is folded round in each case at the upper and lower edge of the balloon control ring  35 . The edge strip  55 ,  56  may have a width b of 5 mm to 10 mm. The end portions  38 ,  39  bent round outwardly at right angles from the hollow cylinder  37  are inserted through the rectangular opening  40 , which crosses the holding element  36 . The holding element  36  has continuous bores  41 ,  42  extending transversely to the end portions  38 ,  39 . The screw connections  43 ,  44  engage through the bores  41 ,  42 . By tightening the screw connections  43 ,  44 , a pressing power is produced by the level contact faces  46  of the holding element  36  and presses the end portions  38 ,  39  against one another. The holding element  36 , with the concave contact face  45  abuts the hollow cylinder  37  and thereby stabilises the cylindrical form of the hollow cylinder  37 . The curvature of the concave contact face  45  is adapted to the curvature of the hollow cylinder  37 . The length of the end portions  38 ,  39  is greater than the depth of the opening  40 . Once the end portions  38 ,  39  have been inserted through the opening  40 , the ends  47 ,  48  therefore project beyond the holding element  36 . The projecting free ends  47 ,  48  are then turned over. The turned over free ends  47 ,  48  then lie in a trough  49  of the holding element  36 . The turning over of the ends  47 ,  48  brings about a secure seat of the hollow cylinder  37  on the holding element  36  and stabilises the balloon control ring  35 . A level contact face  50  of the holding element  36  remote from the hollow cylinder  37  has two positioning cams  51 ,  52 . The positioning cams  51 ,  52  engage, to position the holding element  36 , in bores of the frame wall  32  of the textile machine. Two holding magnets  53 ,  54  are introduced into the level contact face  50  of the holding element  36 . The holding magnets  53 ,  54  adhere on the frame wall  32  and ensure a reliable fixing of the holding element  36 . The holding element  36 , like the holding  13  shown in  FIG. 4 , is an injection moulding made of plastics material. 
         [0033]    When the holding element  36  is fixed by means of the holding magnets  53 ,  54  on the frame wall  32 , the turned over free ends  47 ,  48  contact the frame wall  32 , as shown enlarged for clarity in  FIG. 9 . As a result, an electrically conductive connection, which prevents an electrostatic charge of the hollow cylinder  37 , exists between the hollow cylinder  37  and the frame wall  32 .