Mining Shovel Roller Saddle Block

Abstract

A mining shovel roller saddle block structure has first and second pairs of rollers which roll atop the shovel's dipper handles. Shafts mounted within the rollers are rotatably supported by block clamps fastened to shelves fixed atop the shovel's saddle blocks. Drop stops fixed to the shelves between the rollers extend over the dipper handles. Cables coupled between the block clamps and the drop stops retain the structure if it is dislodged by a collision with greenhorn protrusions on the dipper handles.

What is claimed is: 
     
         1 . A roller saddle block structure for a mining shovel, the structure comprising:
 first and second rollers rotatably mountable atop a first dipper handle of the mining shovel;   third and fourth rollers rotatably mountable atop a second dipper handle of the mining shovel;   a first shaft rotatably mounted within the first roller;   a second shaft rotatably mounted within the second roller;   a third shaft rotatably mounted within the third roller;   a fourth shaft rotatably mounted within the fourth roller;   a first block clamp rotatably supporting the first shaft, the first block clamp fastened to a first shelf fixable atop a first saddle block of the mining shovel;   a second block clamp rotatably supporting the second shaft, the second block clamp fastened to the first shelf;   a third block clamp rotatably supporting the third shaft, the third block clamp fastened to a second shelf fixable atop a second saddle block of the mining shovel; and   a fourth block clamp rotatably supporting the fourth shaft, the fourth block clamp fastened to the second shelf.   
     
     
         2 . A roller saddle block structure as defined in  claim 1 , further comprising:
 a first drop stop fixed to the first shelf between the first and second rollers to extend over the first dipper handle; and   a second drop stop fixed to the second shelf between the third and fourth rollers to extend over the second dipper handle.   
     
     
         3 . A roller saddle block structure as defined in  claim 2 , further comprising:
 a first cable coupled between the first block clamp and the first drop stop;   a second cable coupled between the second block clamp and the first drop stop;   a third cable coupled between the third block clamp and the second drop stop; and   a fourth cable coupled between the fourth block clamp and the second drop stop.   
     
     
         4 . A roller saddle block structure as defined in  claim 2 , further comprising:
 a first cable coupled through the first drop stop between the first block clamp and the second block clamp;   a second cable coupled through the second drop stop between the third block clamp and the fourth block clamp.   
     
     
         5 . A roller saddle block structure as defined in  claim 2 , further comprising:
 a fifth block clamp rotatably supporting the first shaft, the fifth block clamp fastened to the first shelf;   a sixth block clamp rotatably supporting the second shaft, the sixth block clamp fastened to the first shelf;   a seventh block clamp rotatably supporting the third shaft, the seventh block clamp fastened to the second shelf; and   an eighth block clamp rotatably supporting the fourth shaft, the eighth block clamp fastened to the second shelf.   
     
     
         6 . A roller saddle block structure as defined in  claim 5 , further comprising:
 a first cable coupled between the first block clamp and the first drop stop;   a second cable coupled between the second block clamp and the first drop stop;   a third cable coupled between the third block clamp and the second drop stop;   a fourth cable coupled between the fourth block clamp and the second drop stop   a fifth cable coupled between the fifth block clamp and the first drop stop;   a sixth cable coupled between the sixth block clamp and the first drop stop;   a seventh cable coupled between the seventh block clamp and the second drop stop; and   an eighth cable coupled between the eighth block clamp and the second drop stop.   
     
     
         7 . A roller saddle block structure as defined in  claim 5 , further comprising:
 a first cable coupled through the first drop stop between the first block clamp and the second block clamp;   a second cable coupled through the second drop stop between the third block clamp and the fourth block clamp;   a third cable coupled through the first drop stop between the fifth block clamp and the sixth block clamp; and   a fourth cable coupled through the second drop stop between the seventh block clamp and the eighth block clamp.   
     
     
         8 . A roller saddle block structure as defined in  claim 1 , further comprising:
 a flanged rim on the first roller for contacting an outward side of the first dipper handle;   a flanged rim on the second roller for contacting the outward side of the first dipper handle;   a flanged rim on the third roller for contacting an outward side of the second dipper handle; and   a flanged rim on the fourth roller for contacting the outward side of the second dipper handle.   
     
     
         9 . A method of reducing damage caused by collision of protrusions on a mining shovel's dipper handles with saddle blocks supporting the mining shovel's boom, the method comprising:
 rotatably supporting a first roller in a first support structure bolted to a first one of the saddle blocks for rotation of the first roller on a first one of the dipper handles;   rotatably supporting a second roller in a second support structure bolted to the first one of the saddle blocks for rotation of the second roller on the first one of the dipper handles;   rotatably supporting a third roller in a third support structure bolted to a second one of the saddle blocks for rotation of the third roller on a second one of the dipper handles;   rotatably supporting a fourth roller in a fourth support structure bolted to the second one of the saddle blocks for rotation of the fourth roller on the second one of the dipper handles;   coupling a first end of a first cable to the first support structure, extending the first cable through a first stop fixed to the first one of the saddle blocks and coupling a second end of the first cable to the second support structure; and   coupling a first end of a second cable to the third support structure, extending the second cable through a second stop fixed to the second one of the saddle blocks and coupling a second end of the second cable to the fourth support structure.