Abstract:
The invention provides a clamp assembly for holding a set of seal elements to a rail, the assembly including an arm sub-assembly and a locking mechanism. The arm sub-assembly includes first and second arms which are pivotally attached by a pin. The first arm includes an elongate first link portion and a first engagement portion extending substantially transversely to the first link portion. The first engagement portion includes a first contact part which is adapted to engage a selected one of the set of seal elements. In addition, the second arm includes a second link portion and a second engagement portion extending substantially transversely to the second link portion. Also, the second engagement portion includes a second contact part adapted to engage another one of the set of seal elements.

Description:
CROSS-REFERENCE TO OTHER APPLICATIONS 
       [0001]    This application claims the benefit of priority of U.S. Provisional Patent Application No. 61/021,445 filed Jan. 16, 2008, which is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates in general to clamp assemblies and more specifically to a fixed length clamp assembly for a rail. 
       BACKGROUND OF THE INVENTION 
       [0003]    In the prior art, resilient rail seal elements are positioned on both sides of a rail in order to provide a relatively uninterrupted travel path for surface road traffic across the rail, to define a gap adjacent to the rail and to minimize fouling of the ballast by various materials. The rail seal elements need to be held in position, i.e., tightly held against the sides of the rail respectively. 
         [0004]    Such prior art devices are generally adjustable, so that they may be used in various situations, and with rail seal elements having different configurations (i.e., different shapes and/or dimensions). However, the load applied to the rail seal elements by the known devices should be within an optimal range. For example, a clamping device which imposes a relatively small load would not succeed in holding the rail seal elements sufficiently tightly against the rail, resulting in unsatisfactory performance. Foreign material may then get between the rail seal elements and the rail, to push the rail seal elements out of position, or the rail seal elements may become disengaged from the rail and therefore interfere with traffic on or across the rails. 
         [0005]    Also, it is possible for the prior art device to impose a load on the rail seal element(s) which is greater than the optimum range, thereby causing distortion, damage to or breakdown of the rail seal elements and/or the clamping device. 
         [0006]    From the foregoing, it can be seen that the prior art devices have some disadvantages, and such disadvantages involve allowing for input or judgment of the installer as to the appropriate load. There is therefore a significant possibility that the prior art device will be improperly installed, especially if the installer is inexperienced or if working conditions are difficult. 
         [0007]    Therefore, there is a need for an improved clamp assembly to hold rail seal elements against the rail. 
       SUMMARY OF THE INVENTION 
       [0008]    In a broad aspect, the invention provides a clamp assembly for holding a set of seal elements to a rail, the assembly including an arm sub-assembly and a locking mechanism. The arm sub-assembly includes first and second arms which are pivotally attached by a pin. The first arm includes an elongate first link portion and a first engagement portion extending substantially transversely to the first link portion. The first engagement portion includes a first contact part which is adapted to engage a selected one of the set of seal elements. In addition, the second arm includes a second link portion and a second engagement portion extending substantially transversely to the second link portion. Also, the second engagement portion includes a second contact part adapted to engage another one of the set of seal elements. 
         [0009]    The arm sub-assembly is movable between an assembled position and an unassembled position. In the assembled position, the first and second engagement portions hold the set of rail seal elements against the rail and the locking mechanism is engaged to hold the first and second arms substantially fixed relative to each other. In the unassembled position, the locking mechanism is disengaged, allowing the first and second arms to pivot relative to each other about the pin. 
         [0010]    In another aspect of the invention, the locking mechanism can be a tube that is positioned at least partially around the arm sub-assembly. 
         [0011]    In another aspect of the invention, the tube has a slot extending a predetermined distance from the first end toward the second end, and terminating at a stop portion. The slot permits movement of a part of the first engagement portion therein, to allow movement of the arm sub-assembly between the assembled and unassembled positions. 
         [0012]    In yet a further aspect of the invention, an end of the tube is adapted to enable urging of the tube in a longitudinal direction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The invention will be better understood with reference to the attached drawings, in which: 
           [0014]      FIG. 1  is a side view of an embodiment of a fixed length clamp assembly of the invention, in an assembled position; 
           [0015]      FIG. 2  is a top view of the clamp assembly of  FIG. 1  in the assembled position, with a portion of a tube thereof cut away; 
           [0016]      FIG. 3  is a side view of the clamp assembly of  FIG. 1  in the assembled position, engaged with rail seal elements on the sides of a rail; 
           [0017]      FIG. 4  is a side view of the embodiment of the clamp assembly of  FIG. 1 , in an unassembled position; and 
           [0018]      FIG. 5  is a side view of an embodiment of the clamp assembly wherein an end of the tube has been adapted to enable urging of the tube in a longitudinal direction. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Turning to  FIGS. 1 and 2 , an embodiment of a fixed length clamp assembly  20  of the invention is shown in an assembled position. As illustrated, the fixed length clamp assembly  20  includes a locking mechanism, such as a tube  22 , and an arm sub-assembly  23  at least partially positioned therein. The arm sub-assembly  23  includes a first arm  24  and a second arm  26  which are pivotally attached by a pin  27 . As shown in  FIG. 1 , the first arm  24  includes a first arm link portion  28 , and the second arm  26  includes a second arm link portion  30 . Preferably, the first arm  24  also comprises a first arm engagement portion  31 , extending substantially transversely from the first arm link portion  28 , and a first arm contact part  42 . The second arm  26  comprises a second arm engagement portion  32  extending substantially transversely from the second arm link portion  30 , and a second arm contact part  44 . The tube  22  extends between a first end  34  and a second end  36 , and includes a slot  38  extending a predetermined distance from the first end  34  towards the second end  36 , to terminate at a stop portion  40 . The slot  38  permits movement of a part, or portion  41  of the first arm engagement portion  31  therein as the arm sub-assembly  23  is moved between the assembled and the unassembled positions, as will also be described. In the assembled position, the first arm link portion  28  and second arm link portion  30  are substantially aligned and the tube  22  is positioned such that the second end of the tube  36  is abutting or nearly touching the second arm engagement portion  32 . The tube  22  reduces or prevents pivoting of the first and second arms  24  and  26  at the pin  27  such that the first arm link portion  28  and second arm link portion  30  are held in a substantially fixed position relative to each other in the assembled position. 
         [0020]      FIG. 3  illustrates an embodiment of the clamp assembly in the assembled position interacting with rail seal elements  11  and  12 . The first and second rail seal elements  11  and  12  are made of a suitably resilient material and are specifically configured for use on predetermined sides  13  and  14  respectively of a rail  10 . The first and second rail seal elements  11  and  12  have parts  15  and  16  at which the first and second arm contact parts  42  and  44  of the first and second arms  24  and  26  are intended to engage the first and second rail seal elements  11  and  12  to hold them in place against the rail  10 . 
         [0021]    It will be appreciated that the first and second arms  24  and  26  are formed and sized so that, when the arm sub-assembly  23  is in the assembled position, the first and second arm contact parts  42  and  44  are spaced apart from each other by a fixed distance “D”, thereby providing a fixed length clamp assembly. This results in lateral loading of the first and second rail seal elements  11  and  12  that can be determined in advance for a known type of rail seal element and type of rail. 
         [0022]    The arm sub-assembly  23  is movable between the assembled position, in which the first and second engagement portions  31  and  32  hold the first and second rail seal elements  11  and  12  against the rail  10 , and the unassembled position, in which the second arm  26  is pivotal about the pin  27  relative to the first arm  24 . 
         [0023]      FIG. 4  illustrates an schematic diagram of the clamp assembly in the unassembled position. When the arm sub-assembly  23  is moved relative to the tube  22  by at least a predetermined distance in the direction of arrow “A”, the first arm link portion  28  extends sufficiently beyond the second end  36  such that the pin  27  is positioned outside the tube  22 , thereby permitting the second arm  26  to pivot about the pin  27 . 
         [0024]    Such relative movement can be achieved by movement of the tube  22  in the direction of arrow “B” relative to the arm sub-assembly  23 , e.g. by urging the second end  36  of the tube  22 . Movement of the arm sub-assembly  23  in the direction indicated by arrow “A” is assisted by the configuration of the slot  38 , into which the part  41  of the first arm engagement portion  31  is receivable. Movement of the part  41  in the direction indicated by arrow “A” relative to the tube  22  is limited by the stop portion  40 , when the part  41  of the first arm engagement portion  31  engages the stop portion  40 . 
         [0025]      FIG. 5  illustrates an embodiment of the clamp assembly in the assembled position wherein an end of the tube  22  has been adapted to enable urging of the tube in a longitudinal direction. The first end  34  of the tube  22  includes a cap  50  that extends beyond the edge of the first end  34 . The cap  50  enables a device to catch the first end  34  and urge it in a longitudinal direction away from the second arm  26 . For example, a rod could be used to lever the tube  22  by placing an end of the rod against the cap and using the first arm  24  as a fulcrum. 
         [0026]    In use, the arm sub-assembly  23  is movable from the unassembled position to the assembled position by first aligning the first and second arm link portions  28  and  30 , and then moving the arm sub-assembly  23  relative to the tube  22  in the direction indicated by arrow “B” in  FIG. 4 . Such relative movement can be achieved by movement of the tube  22 , e.g. by urging the first end  34  of the tube  22 , toward the pin  27 . Preferably, the arm sub-assembly  23  is so moved until it is in the assembled position, as shown in  FIG. 1 . It will be understood that, as the arm sub-assembly  23  is moving to the assembled position, the second arm link portion  30  passes through the second end  36  and into the tube  22 . 
         [0027]    One procedure for mounting the clamp assembly on the rail and the rail seal elements  11  and  12  is as follows. The clamp assembly  20  in the unassembled position is inserted into and pushed through ballast (not shown) underneath the rail  10  and the rail seal elements  11  and  12 . As shown in  FIG. 3 , this is generally done in the direction indicated by arrow “C” relative to the rail  10  and rail seal elements  11  and  12 . The clamp assembly  20  is pushed into the ballast with the second arm  26  leading and then moved underneath the rail  10  until the assembly  20  is substantially transverse to the rail and the first and second arm contact parts  42  and  44  are substantially outside the rail seal elements. 
         [0028]    At this point, the first and second arm engagement portions  31  and  32  are then rotated upwardly, so that the first and second arm link portions  28  and  30  are substantially aligned, the first and second arm engagement portions  31  and  32  are substantially vertical, and the respective first and second arm contact parts  42  and  44  are generally positioned to engage the parts  15  and  16  of the rail seal elements  11  and  12 . 
         [0029]    In order to lock the clamp assembly in the assembled position, the first end  34  is urged in the direction of arrow C. As noted above, this can conveniently be done with any suitable tool. This causes the tube  22  to move in the direction of arrow C, and pushes the second end  36  of the tube  22  against a corner part  48  of the second arm engagement portion  32 . The first and second arm engagement portions  31  and  32  are thus forced to engage the rail seal elements  11  and  12 . When the tube  22  is moved as far as possible in direction C, the clamp assembly  20  is in the assembled position. As the clamp has a fixed length, the force being applied to the rail seal elements is known and therefore pre-determined. 
         [0030]    In order to cause the first and second arms to release the rail seal elements, the second end  36  of the tube  22  is urged or pried in the direction of first arm  24 . The fixed length clamp assembly  20  can then be put into the unassembled position and removed, if desired. 
         [0031]    From the foregoing, it can be seen that the fixed length clamp assembly is for use where the outer surfaces of the rail seals are spaced apart by a known distance, within a relatively small tolerance. The clamp assembly of the invention therefore enables a known load to be imposed on the rail seal elements, i.e., a load which is within the optimal range therefor, with minimal scope for input from the installer. 
         [0032]    It will be appreciated by those skilled in the art that the invention can take many forms, and that such forms are within the scope of the invention as described herein. Therefore, the spirit and scope of the invention should not be limited to the descriptions of the preferred versions contained herein.