Abstract:
A clamping device for coupling a transport device, for example a cabin, gondola, or a chair, to the hauling or traction cable of a cableway system. The clamping device contains two clamping jaws that can be moved toward one another or apart for coupling the clamping device to and uncoupling it from the hauling or traction cable. Exchangeable jaws, via which the clamping jaws act on the hauling or traction cable, are fastened to the clamping jaws. A bearing surface on the clamping jaws for the exchangeable jaws is curved concavely, and a counter surface on the exchangeable jaws has a corresponding curvature.

Description:
BACKGROUND OF THE INVENTION  
     Field of the Invention  
       [0001]     The invention relates to a clamping device for coupling a transport device, for example a cabin, a gondola or a chair, to the hauling or traction cable of a cableway system. The clamping device has two clamping jaws which can be moved toward one another or apart for coupling the clamping device to and uncoupling it from the hauling or traction cable. The clamping device has exchangeable jaws, via which the clamping jaws act on the hauling or traction cable, being fastened to the clamping jaws.  
         [0002]     In clamping devices for coupling transport devices, for example cabins, gondolas, or chairs, to the hauling or traction cable of a cableway system, such as are known from Austrian patent AT 404 458 B for example, use is made of lever systems which act on the hauling or traction cable of the cableway system via clamping jaws. Owing to wear on the clamping jaws and on the cable, modification of the clamping device or replacement of the cable, it may be necessary either to remachine the clamping jaws or, if this is not possible, to replace them completely. In order to avoid this, it has already been proposed to mount exchangeable jaws, which bore against the clamping jaws via a plane bearing surface and were fastened there, on the clamping jaws. While this form of exchangeable jaws solved the problem of remachining or replacing the clamping jaws, the configuration nevertheless meant that there was a relatively great material requirement for the clamping jaws and the exchangeable jaws, and the seating of the exchangeable jaws on the clamping jaws was not entirely satisfactory either.  
       SUMMARY OF THE INVENTION  
       [0003]     It is accordingly an object of the invention to provide a clamping device for coupling a transport device which overcomes the above-mentioned disadvantages of the prior art devices of this general type.  
         [0004]     With the foregoing and other objects in view there is provided, in accordance with the invention, a clamping device for coupling a transport device to a hauling or traction cable of a cableway system. The clamping device contains two clamping jaws moveble toward one another or apart for coupling the clamping device to and uncoupling the clamping device from the hauling or traction cable. Exchangeable jaws, through which the clamping jaws act on the hauling or traction cable, are fastened to the clamping jaws. The clamping jaws have a bearing surface for receiving the exchangeable jaws, the bearing surface is curved concavely. The exchangeable jaws have a counter surface with a curvature corresponding to the bearing surface.  
         [0005]     Owing to the concavely curved bearing surface on the clamping jaws, or the associated and correspondingly convexly curved counter surface on the exchangeable jaws, both problems are solved at once. On the one hand, the exchangeable jaws have an substantially cylindrical cross-sectional shape, so that material can be saved on the exchangeable jaws in comparison with the prior art, and, on the other hand, very good seating of the exchangeable jaws on the clamping jaws is brought about by virtue of the arched curvature of the bearing surface and counter surface.  
         [0006]     In a preferred embodiment of the invention, the bearing surface and the counter surface are curved with a circular cylindrical shape. This embodiment results in surfaces that are easy to produce and, as mentioned, good seating.  
         [0007]     A further preferred embodiment of the invention is characterized in that the contact surface with which an exchangeable jaw acts on the hauling or traction cable has a shape that is substantially parallel to the counter surface.  
         [0008]     As the cable has a round cross section, the radius of curvature of which is greater than the radius of curvature of the contact surface in the central curvature region, a contact region which is formed of two strip-shaped contact surfaces spaced from one another is brought about on each exchangeable jaw, by virtue of which very good contact between cable and exchangeable jaws is achieved.  
         [0009]     In a development of the invention, provision can be made in this connection that the radius of curvature of the contact surface increases outward from the central region and in particular merges with a substantially plane region.  
         [0010]     Alternatively or additionally, provision can be made that the contact surface contains groove-shaped depressions or a slot-shaped depression in the central region. Contact regions, with which the exchangeable jaws bear against the cable in an accurately defined way, are produced above and below this slot or these grooves.  
         [0011]     In order to fasten the exchangeable jaws to the clamping jaws, provision can be made, as is known per se, that the exchangeable jaw contains two cheeks that extend laterally next to the clamping jaws.  
         [0012]     In a preferred development of the invention, provision can be made in this connection that the cheeks contain a shoulder on the sides facing one another, the distance between projections of the shoulder of the two cheeks being smaller than the distance between returns on the cheeks.  
         [0013]     By virtue of the shoulders or the projections, the contact region on the clamping jaws can be defined very accurately on the cheeks, which results in accurately calculable loading conditions on the exchangeable jaws.  
         [0014]     In this connection, it is preferred within the scope of the invention if the projection is disposed in the region next to the counter surface of the exchangeable jaw.  
         [0015]     This embodiment affords the advantage that shear forces acting on the exchangeable jaws in the longitudinal direction of the cable exert only very small bending forces on the cheeks, by virtue of which the loading in the critical transition region between counter surface and cheeks can be kept small, which further results in favorable dimensioning of the exchangeable jaws.  
         [0016]     In this connection, it is preferred within the scope of the invention if the width of the projection is approximately 15-50%, preferably 20-30%, of the width of the cheek.  
         [0017]     As is known per se from the prior art, the exchangeable jaws are connected to the clamping jaws via sleeves which are inserted through mounting bores in the cheeks and into corresponding bores in the clamping jaws and are screwed tight there. With this form of fastening, it is preferred within the scope of the invention if the projection extends as far as approximately into the region of a mounting bore or slightly into the region of the mounting bore, as in this way the fastening arrangements, that is the sleeves and the screws, are exposed to only very small loads when force transmission takes place from the exchangeable jaws to the clamping jaws.  
         [0018]     Other features which are considered as characteristic for the invention are set forth in the appended claims.  
         [0019]     Although the invention is illustrated and described herein as embodied in a clamping device for coupling a transport device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.  
         [0020]     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a diagrammatic, perspective view of a clamping device according to the invention;  
         [0022]      FIG. 2  is a diagrammatic, perspective view of a part of the clamping device from  FIG. 1  in a dismantled state; and  
         [0023]      FIG. 3  is a diagrammatic, perspective view of an exchangeable jaw. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is shown a clamping device which, as is known per se from Austrian patent AT 404 458 B, contains two clamping levers  1  and  2 , which are interconnected at a joint  3 . A roller  4 ,  5  is mounted on each clamping lever  1 ,  2 ; the rollers run partly along guide rails in the stations of a cableway. With a suitable course of these guide rails, the clamping levers  1 ,  2  can be pivoted in relation to one another by the rollers  4 ,  5 , by virtue of which clamping jaws  6 ,  7  can be moved toward one another or apart as the clamping jaw  6  is attached to the clamping lever  2  and the clamping jaw  7  is attached to the clamping lever  3 . In  FIG. 1 , the clamping device is illustrated in the closed position, in which a non-illustrated cable would be clamped firmly between the clamping jaws  6 ,  7 . If the clamping levers  1 ,  2  are pivoted by the rollers  4 ,  5 , moving apart, a spring  8  on the clamping lever  2  is compressed and thus still further prestressed by a toggle lever pair  9  which is mounted in an articulated manner on the clamping lever  1  and the other end of which is guided displaceably on the clamping lever  2  by a sleeve  10 . At the same time, the clamping jaws  6 ,  7  are opened and the non-illustrated cable would be released.  
         [0025]     As the clamping jaws  6 ,  7  are subject to wear in their contact region with the cable, this wear on the contact surfaces has to be compensated for at regular intervals. It can also occur that the cable diameter changes owing to replacement of the cable, whether because of maintenance or for other reasons. In this case as well, the clamping jaws  6 ,  7  can be adapted to the new cable diameter very easily with the aid of the invention.  
         [0026]     In order for it to be possible to carry this out in a simplified manner, exchangeable jaws  11  are mounted on the clamping jaws  6 ,  7 . The exchangeable jaws contain a central part  12  which has on its rear side a cylindrically curved counter surface  13  for a correspondingly curved bearing surface  14  on each clamping jaw  6 ,  7 . The contact surface  15  on that side of the central part  12  facing the cable has a shape which is substantially but not entirely parallel to the counter surface  13 . The contact surface  15  contains a central region on which a longitudinally extending slot  16  or grooves are provided. Contact regions with which the exchangeable jaws  11  bear flat against the cable in a defined way are located above and below this slot  16  or these grooves. This configuration of the contact surfaces results in very reliable clamping action.  
         [0027]     Alternatively, it would also be possible to configure the contact surface in the central region with a radius of curvature that is smaller than the radius of the cable. The radius of curvature then increases outward, that is at the top and at the bottom toward the longitudinal edges of the central region  12 , so that the exchangeable jaws  11  are applied against the cable only in these regions with a larger radius of curvature. Very reliable clamping action can also be achieved in this way.  
         [0028]     For fastening the exchangeable jaws  11  to the clamping jaws  6 ,  7 , the exchangeable jaws  11  contain cheeks  17 ,  18  which extend laterally next to the clamping jaws  6 ,  7 . A bore  19  is provided in each cheek, and a bore  20  is provided on each side of the clamping jaws  6 ,  7 . A sleeve  21  is inserted through the bore  19  in each cheek  17 ,  18  and into each bore  20  in the clamping jaws  6 ,  7  and is then screwed tight to the clamping jaws  6 ,  7  with a screw  22 . The exchangeable jaws  11  are therefore fixed to the clamping jaws  6 ,  7  only with the aid of these sleeves  21 , these sleeves not having to transmit any appreciable forces, as the exchangeable jaws  11  are held very well force-lockingly and form-lockingly by the concavely curved bearing surfaces  14  on the clamping jaws  6 ,  7  and the correspondingly convexly curved counter surfaces  13  on the exchangeable jaws  11  in the transverse direction to the longitudinal extent of the cable or of the exchangeable jaws  11  and by the frictional forces acting between these surfaces  13 ,  14 .  
         [0029]     In order to transmit the forces acting in the longitudinal direction of the cable as well positively from the exchangeable jaws  11  to the clamping jaws  6 ,  7 , the cheeks bear with their surfaces  23  facing the clamping jaws  6 ,  7  against the associated surfaces  24  of the clamping jaws  6 ,  7  with small play. In order to prevent undesirably high bending forces acting on the cheeks  17 ,  18 , or the transition region between the cheeks  17 ,  18  and the central part  12 , the inner surfaces  23  of the cheeks  17 ,  18  contain a shoulder  25 , the distance between projections  23 b of the shoulder  25  of the two cheeks  17 ,  18  being smaller than the distance between returns  23   a.  Consequently, the cheeks actually bear against the side surfaces  24  of the clamping jaws  6 ,  7  only with the regions  23   b  lying close to the counter surface  13 . The longitudinal forces to be transmitted from the clamping jaws  6 ,  7  via the cheeks  17 ,  18  to the central part  12  and on to the cable are therefore transmitted primarily as shear forces from the cheeks  17 ,  18  to the central part  12 , the bending forces acting on the cheeks  17 ,  18 , or on the transition region between the cheeks  17 ,  18  and the central part  12 , being relatively small owing to the short lever arm, which has a positive effect on loading and as a further result dimensioning of the exchangeable jaws  11 .  
         [0030]     By virtue of the substantially parallel shape of the contact surface  15  on that side of the central part  12  facing the cable and of the counter surface  13  facing the clamping jaws  6 ,  7 , the cross section of the central part of the exchangeable jaws  11  is substantially cylinder-wall-shaped, which results not only in a material saving in comparison with the known exchangeable jaws but also favorable loading and force-transmission conditions on the central part.  
         [0031]     By virtue of this, it is also possible to find cost-effective solutions in the selection of the material for the exchangeable jaws which also form optimum combinations with regard to the friction and wear conditions as far as the material pairings between the clamping jaws  6 ,  7  and the exchangeable jaws  11  on the one hand and the exchangeable jaws  11  and the cable on the other hand are concerned.  
         [0032]     This application claims the priority, under 35 U.S.C. §119, of Austrian patent application No. 1842/2004, filed Nov. 4, 2004; the entire disclosure of the prior application is herewith incorporated by reference.