Abstract:
A plate-link chain including plates having at least one ear, and rocker pressure members interconnecting the plates. The wear of chain guide tracks or guide rails during movement of the plate-link chain relative to the guide tracks or guide rails is reduced by removing the ears from the plates after the plate-link chain is assembled. The ear removal is effected by machining or grinding off the ears.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a plate-link chain that includes plates having at least one ear on an outer edge and rocker pressure members connecting the plates, as well as to a method for producing such a chain.  
         [0003]     2. Description of the Related Art  
         [0004]     Plate-link chains, as well as toothed plate-link chains, have ears as assembly aids, which are located on the outwardly-facing side of the chain when it is in the installation position. Plate-link chains, or toothed plate-link chains, are employed in continuously variable transmissions, known as CVT&#39;s, for example. Because of the ears, after rather long use there is increased guide track or guide rail wear on guide tracks or guide rails provided for guiding the chain or for limiting transverse oscillations of the chain.  
         [0005]     An object of the present invention is therefore to provide a plate-link chain, which can be a toothed plate-link chain, and a method for producing it, which reduces the wear of the guide tracks or guide rails.  
       SUMMARY OF THE INVENTION  
       [0006]     The object is achieved by a plate-link chain that includes plates having at least one outer ear, and rocker pressure members that connect the plates, wherein the ear is removed after the plate-link chain is assembled. The object is also achieved by a method for producing a plate-link chain that includes plates having at least one outer ear, and rocker pressure members interconnecting the plates, including the procedural steps of assembly of the plates and rocker pressure members and the removal of the ear. In that regard, the term plate-link chain also includes a toothed plate-link chain. As a rule, there are one or two ears arranged on each plate. But there can also be one or more ears arranged on only some of the plates. Thus, in accordance with the present invention the ears are removed only after the chain has been completely assembled.  
         [0007]     Preferably, it is provided that the ear be removed by machining. The machining preferably includes grinding, with special preference for wet and/or dry grinding. Metallic particles are preferably removed from the processing site during the processing, which is preferably accomplished magnetically and/or by means of a flowing medium, in particular a liquid or pressurized air.  
         [0008]     The machining depth is preferably determined so that that no heat treatment of the rocker members occurs, in particular no tempering, and the prior heat treatment of plates and rocker pressure members is not changed. Preferably there is provision for the plate-link chain to be stretched in a further processing step. The removal of the ear is preferably followed by a cleaning step, which is preferably performed by means of pressurized air and/or a cleaning fluid. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The structure, operation, and advantages of the present invention will become further apparent upon consideration of the following description, taken in conjunction with the accompanying drawings in which:  
         [0010]      FIG. 1  is a side view of a section of a known plate-link chain;  FIG. 2  is a top view of the plate-link chain shown in  FIG. 1 ;  
         [0011]      FIG. 3  is a side view similar to  FIG. 1  of another plate-link chain with plate links having ears and after assembly;  
         [0012]      FIG. 4  is a side view of the plate-link chain of  FIG. 3  after removal of the ears; and  
         [0013]      FIG. 5  is a flow chart showing the several steps of the method in accordance with the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]      FIG. 1  is a side view of a section of a known plate-link chain, and  
         [0015]      FIG. 2  shows a schematic top view of the plate-link chain shown in  FIG. 1 . Such a plate-link chain is assembled from plates  10 , which are arranged one after another in a predetermined pattern in a plurality of side-by-side rows relative to the longitudinal direction of the plate-link chain. In the illustrated example  41  rows are shown. The plates of at least some adjacent rows are offset from each other in the longitudinal direction of the plate-link chain, so that a group of pins or pairs of rocker pressure members  14  that extend through and interconnect the plates and that extend transversely of the plate-link chain, in each case extend through at least two plates that are arranged offset from each other in the longitudinal direction. More precisely, a pair of rocker pressure members  14   a  extends through plates  10 A and plates  10 B; a pair of rocker pressure members  14   b  extends through plates  10 B and plates  10 C; a pair of rocker pressure members  14   c  extends through plates  10 C and again plates  10 A, whereupon the arrangement repeats.  
         [0016]     The pair of rocker pressure members  14   a  extends through the plates  10 B in such a way that it is positioned at the front end of an opening  16  in the plates, which opening extends in the running direction of the plate-link chain (the direction shown by the arrow), whereas it is at the rear end of the openings of plates  10 A in the running direction of the plate-link chain. The arrangement is analogous for the other pairs of rocker pressure members. In that way the outer surface of the front rocker pressure member  14   1  of rocker pressure member pair  14   a  which lies forwardmost in the running direction is supported at the front end of opening  16  of plates  10 B, whereas the rear end of opening  16  of plates  10 A is supported on the outer surface of the rear rocker pressure member  142  of rocker pressure member pair  14   a . The openings and the rocker pressure members that contact the ends of the openings are so shaped that the rocker pressure members are nonrotatably held at the respective associated end faces of the openings. When the chain bends, the mutually facing surfaces  18   1  and  18   2  of the rocker pressure members of a rocker pressure member pair roll against each other, so that there is largely friction-free bending of the plate-link chain.  
         [0017]      FIG. 3  shows a side view similar to  FIG. 1  of a plate-link chain immediately after assembly. The plate-link chain shown in  FIG. 3  includes plates  10 , which have substantially flat upper surfaces, with only small concave or convex regions between the rocker members of a rocker member pair. The result is that in contrast to the chain illustrated in  FIG. 1 , when the assembled chain of  FIG. 3  is stretched it has an essentially straight and flat upper surface, as shown in  FIG. 4 . As an aid to chain assembly, during production plates  10   a ,  10   b ,  10   c  are each provided with two ears  20  having an ear height CH. Among other things, the ears  20  can serve to position the plates  10  relative to each other in the running direction of the chain during assembly of the chain, and also to enable introduction of the rocker pressure members  14  into the openings in plates  10 , for example. The ears  20  are produced, for example, when stamping the plates  10 . In accordance with the present invention, the ears are removed only after the chain is assembled, so that in side view the chain has the form shown in  FIG. 4 , i.e., without the ears  20 . The method for assembling the chain and removing the ears will be described below.  
         [0018]     The manufacturing process will be described on the basis of the flow chart shown in  FIG. 5 . The process begins at Step  101 , after the chain has been assembled. In Step  102  assembly ears  20  are ground off or cut off on a linear grinding machine. The chain is then in a stretched, pre-tensioned condition, in order to ensure alignment of the plates relative to each other. The grinding or cutting off operation on the linear grinding machine is done with as little residual dust as possible, i.e., with the chain cleaned, and with as little burr formation as possible in or on the chain. The low burr formation is achieved by strong suctioning of the dust particles, slow feeding while grinding (which results in a shallow cutting depth) and a powerful magnet by the grinding wheel to transport machined material away. When machining with coolant, provision is made for a high flow rate of rinsing or cooling agent, in order to reduce the heat treatment of the plate by the machining. A process of washing the chain follows in Step  103 , in particular if the grinding or cutting in Step  102  is done without the addition of cooling agents or lubricants. Otherwise Step  103  can be dispensed with. That is followed by stretching the chain in Step  104 , which is intended to press out the burr that has developed in the loop, and with the plates side-by-side. In addition, the stretching checks whether any prior damage to the plate contour could result in rejects. The process ends at Step  105 .  
         [0019]     Although particular embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit of the present invention. It is therefore intended to encompass within the appended claims all such changes and modifications that fall within the scope of the present invention.