Abstract:
A mining bit puller having a striking pad is disclosed. The puller has a plate with two forks at a front end and a striking pad at a back end. In one embodiment, the forks are generally wedge shaped, and the puller includes a handle extending at an angle from the top of the bit puller plate. During mining tool bit changeout operations, the pad may be struck with a hammer or other tool in order to force the forks between a collar of the tool bit and its mounting block to pull the tool bit out of the block.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to mining bit extractors, and more particularly relates to a puller having a striking pad.  
       BACKGROUND INFORMATION  
       [0002]     Mining tools include generally conical tool bits which are removably installed in mounting blocks attached to rotating drums. When the tool bits become worn, they are pulled from their blocks and replaced. Puller tools are used to extract the tool bits. One type of puller has wedge-shaped forks which slide between a collar of the tool bit and the mounting block to force the bit out of the block. In order to insert the forks, it is often necessary to strike the back of the puller. However, in conventional pullers, striking of the puller with a hammer or other tool can cause flying metal shards.  
       SUMMARY OF THE INVENTION  
       [0003]     The present invention provides a mining bit puller having a striking pad. The puller has a plate with two forks at a front end and a striking pad at a back end. During mining tool bit changeout operations, the pad may be struck with a hammer or other tool in order to force the forks between a collar of the tool bit and its mounting block to pull the tool bit out of the block.  
         [0004]     An aspect of the present invention is to provide a mining bit puller for extracting mining tool bits. The puller comprises a bit puller plate including two forks at a front end of the plate and a striking pad at a back end of the plate. In one embodiment, the forks are generally wedge shaped, and the puller includes a handle extending at an angle from the top of the bit puller plate.  
         [0005]     Another aspect of the present invention is to provide a mining bit puller for extracting mining tool bits, wherein the puller comprises a bit puller plate including two forks at a front end of the plate, and a back end of the plate is structured and arranged to receive a striking pad.  
         [0006]     A further aspect of the present invention is to provide a striking pad for a mining bit puller, wherein the striking pad comprises a striking surface, and means for connecting the striking pad to the puller.  
         [0007]     These and other aspects of the present invention will be more apparent from the following description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is an isometric view of a mining bit puller including a striking pad in accordance with an embodiment of the present invention.  
         [0009]      FIG. 2  is a side view of the mining bit puller of  FIG. 1 .  
         [0010]      FIG. 3  is a rear view of the mining bit puller of  FIG. 1 .  
         [0011]      FIG. 4  is a top view of a bit puller plate with a portion of the plate and a striking pad shown in section in accordance with an embodiment of the present invention.  
         [0012]      FIG. 5  is a side view of the bit puller plate of  FIG. 4  with a portion of the plate and the striking pad shown in section.  
         [0013]      FIG. 6  is a rear view of a bit puller plate including an annular recess and threaded hole in accordance with an embodiment of the present invention.  
         [0014]      FIG. 7  is a side view of a puller striking pad in accordance with an embodiment of the present invention.  
         [0015]      FIG. 8  is an isometric view showing the rear of a bit puller plate including a rectangular striking pad in accordance with another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0016]      FIGS. 1-3  illustrate a mining bit puller  10  having a bit puller plate  20  in accordance with an embodiment of the present invention. The bit puller plate  20  includes a mid section  22 , a front end having two generally wedge-shaped forks  24   a  and  24   b , and a back end  26 . The forks  24   a  and  24   b  are structured and arranged to be inserted between a mining tool bit and its mounting block in order to remove the tool bit from its block. A handle  28  extends at an angle A from the top of the bit puller plate  20 . For example, the handle  28  may be oriented at an angle A of less than 90 degrees with respect to a plane defined by the bit puller plate  20 , e.g., from about 40 or 50 degrees to about 70 or 80 degrees. A hand grip  29  is provided at the end of the handle  28 . The bit puller plate  20  and the handle  28  may be made of any suitable material such as steel. The bit puller plate  20  and handle  28  may be welded together. The hand grip  29  may be made of any suitable material such as rubber or plastic.  
         [0017]     In accordance with the present invention, a striking pad  30  is provided at the back end  26  of the bit puller plate  20 . The striking pad  30  is preferably made of a resilient material such as polymers, plastics, elastomers, rubber, soft metals, leather, wood products, natural fibers or the like. When the puller  10  is used for extracting mining tool bits (not shown), the wedge-shaped forks  24   a  and  24   b  may be forced between a collar of the tool bit and its mounting block by striking the pad  30  with a hammer or other suitable tool. The striking pad  30  thus should be made of a material capable of withstanding repeated striking forces.  
         [0018]     The striking pad  30  may be fastened to the back end  26  of the bit puller plate  20  by any suitable means such as mechanical fasteners, press fittings, welding, adhesives and the like.  FIGS. 4-7  illustrate embodiments of the present invention in which the striking pad  30  is fastened to the back end  26  of the bit puller plate  20  by mechanical fastening. In this embodiment, the striking pad  30  has a circular cross section and includes a circular extension  32  extending in an axial direction from the striking pad  30 . The extended portion  32  is received in an annular recess  27  in the back  26  of the bit puller plate  20 .  
         [0019]     As shown in  FIG. 4 , the body of the striking pad  30  has an axial length L 1  which is greater than an axial length L 2  of the extended portion  32 . For example, the axial length L 1  may be from about 0.5 to about 10 times greater than the axial length L 2  of the extended portion  32 . The axial length L 1  is typically from about 0.25 to about 1.5 inches, while the axial length L 2  of the extended portion  32  is typically from zero to about 0.75 inch.  
         [0020]     As shown in  FIG. 4 , the body of the striking pad  30  has a diameter D 1  which is greater than a diameter D 2  of the extended portion  32 . For example, the diameter D 1  may be from about 0.1 to about 5 times greater than the diameter D 2  of the extended portion  32 . The diameter D 1  may typically be from about 0.5 to about 2 or 3 inches, while the diameter D 2  may typically be from about 0.5 to about 2 inches.  
         [0021]     As shown most clearly in  FIGS. 4, 5  and  7 , the striking pad  30  includes a threaded bolt  36  which may be attached to a metal plate  34  at least partially embedded in the striking pad  30 . The metal plate  34  may be integrally formed with the threaded shaft  36 , e.g., the plate  34  may comprise a bolt head.  
         [0022]     As shown most clearly in  FIGS. 4-6 , the bit puller plate  20  includes an annular recess  27  with a threaded hole  25  at the center thereof. The extended portion  32  of the striking pad  30  fits within the annular recess  27  of the bit puller plate  20 . The threaded shaft  36  of the striking pad  30  may be threaded into the hole  25  of the bit puller plate  20 . Although the striking pad  30  is mechanically fastened to the bit puller plate  20  in the embodiment shown in  FIGS. 4-7 , any other suitable means of attachment may be used in accordance with the present invention.  
         [0023]      FIG. 8  illustrates the rear of a bit puller plate  40  in accordance with another embodiment of the present invention. The embodiment shown in  FIG. 8  is similar to the previous embodiments, except a generally rectangular striking pad  42  is used instead of a circular striking pad. The rectangular striking pad  42  may be attached to the back end  26  of the bit puller plate  40  by any suitable means such as adhesives, press fittings, mechanical fasteners, welding and the like. The rectangular striking pad  42  may include an extended portion (not shown) which is received in a corresponding recess (not shown) in the back end  26  of the bit puller plate  40 . For example, the rectangular striking pad  42  may have a rectangular extension or, alternatively, a circular extension similar to the circular extension  32  shown in  FIGS. 4, 5  and  7 . In addition to rectangular and circular cross sections, any other suitable shape of striking pad may be used in accordance with the present invention.  
         [0024]     Although the pullers shown in the figures have generally wedge shaped forks  24   a  and  24   b , other fork shapes may be used in accordance with the present invention. For example, the forks may be substantially flat instead of wedge shaped. Furthermore, although the pullers illustrated in the figures include a handle  28  extending at an angle from the top of the bit puller plate  20 , other handle arrangements may be used in accordance with the present invention. For example, a handle may extend from the back end of the bit puller plate. In this case, the striking pad may be mounted at the end of the handle at the back end of the bit puller plate.  
         [0025]     Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims.