Reciprocating Saw with Reinforced Offset Saw Blade Holder

Abstract

An improved offset saw blade mounting assembly for use on a reciprocating power saw tool includes a shim member that is used to fill a central slot of the tool drive shaft. The shim member fills the slot and serves to reinforce the drive shaft and thereby reduce the likelihood of the drive shaft failing. The shim member is part of an insert that is received within an interior bore of the offset mounting assembly. A finger guard is also provided that substantially closes off any opening which may occur between the mounting assembly and the power tool.

What is claimed is: 
     
         1 . A reciprocating saw, comprising:
 a body, a drive shaft mounted within the body for reciprocating movement along a first axis, the drive shaft including a free end extending out of said body and past a front end portion thereof, the drive shaft free end including a slot extending axially rearwardly therein and defining two drive shaft halves separated by the slot,   a saw blade mounting block, the mounting block having a body portion which fits over said drive shaft, the mounting block body portion including an interior, axial bore that receives at least a portion of said drive shaft therein, said mounting block further including a saw blade support portion formed with said mounting block body portion, the saw blade support portion supporting a saw blade along a second axis spaced apart from the first axis, said mounting block body portion further including a retainer for retaining said mounting block body portion in place over said drive shaft,   said mounting block body portion axial bore including an insert received therein, the insert including a plate-shaped shim member extending in and completely filling said drive shaft slot in order to reduce the likelihood of damage to said drive shaft during operation of said saw.   
     
     
         2 . The reciprocating saw of  claim 1 , wherein said shim member and said insert are formed separate from said mounting block. 
     
     
         3 . The reciprocating saw of  claim 1 , wherein said shim member is dimensioned to match like dimensions of said drive shaft slot. 
     
     
         4 . The reciprocating saw of  claim 1 , wherein said insert includes a tubular body portion that contains said shim member therein, part of the insert tubular body portion extending over at least a portion of said drive shaft. 
     
     
         5 . The reciprocating saw of  claim 4 , wherein said insert tubular body portion includes an outer shoulder that contacts an opposing surface of said mounting block. 
     
     
         6 . The reciprocating saw of  claim 1 , wherein said mounting block axial bore includes an interior counterbore, and at least a portion of said insert is received within said counterbore. 
     
     
         7 . The reciprocating saw of  claim 1 , wherein said insert has a face that lies flush with a face of said mounting block. 
     
     
         8 . The reciprocating saw of  claim 1 , further including a guide assembly attached to the body front end portion, the guide assembly defining a guide channel in which said mounting block and said saw blade move in reciprocating movement in response to movement of said drive shaft. 
     
     
         9 . The reciprocating saw of  claim 8 , wherein said guide assembly includes a baseplate and two spaced-apart guide arms disposed at angles to the baseplate, and extending outwardly from said baseplate and the guide arms cooperatively defining said guide channel, said guide arms having a width which extends over an area between said body front end portion and a rear edge of said mounting block, and said guide assembly further includes a rearwardly-facing guard plate at least partially closing off an area between said guide arms and said saw body to guard against the ingress of an operator's fingers or clothing therein during operation of said saw. 
     
     
         10 . The reciprocating saw of  claim 9 , wherein the guard plate has a U-shaped configuration defining a guard plate backbone portion which is connected to two leg portions. 
     
     
         11 . The reciprocating saw of  claim 9 , wherein said baseplate is disposed along one side of said saw body front end portion, and said guide arms extend outwardly from one side of said baseplate across said saw body front end portion toward an opposite side of said saw body front end portion, and a handle extends outwardly away from an opposite side of said baseplate, said baseplate further including a fastener that extends between said baseplate and said body front end portion to resist movement of said guide assembly about said tool, the fastener including a reinforcing collar interposed between said baseplate and said fastener. 
     
     
         12 . A reciprocating saw, comprising:
 a saw body, a drive shaft mounted within the saw body for reciprocating movement, the drive shaft including a free end extending out of said saw body and past a front end portion thereof, the drive shaft free end including a slot extending axially rearwardly therein and defining two shaft halves separated by the slot,   a saw blade mounting block, the mounting block including an axial bore that receives an insert therein, said mounting block further including a saw blade support portion spaced apart from the said drive shaft and which supports a saw blade spaced apart from said drive shaft, said mounting block body portion further including a retainer for retaining said mounting block in place on said drive shaft,   an insert received in the mounting block bore, the insert including a plate-shaped shim member extending into and completely filling said drive shaft slot,   a guide assembly attached to said body front end portion, the guide assembly defining a guide channel which at least partially surrounds said mounting block, said guide assembly including a baseplate and two guide arms disposed at angles to the baseplate, said baseplate and the guide arms cooperatively defining said guide channel, and said guide assembly further including a rear-facing guard plate that interconnects said guide arms together to guard against the ingress of an operator's fingers or clothing therein during operation of said saw.   
     
     
         13 . The reciprocating saw of  claim 12 , wherein said mounting block includes a counterbore and said insert is received within the mounting block counterbore. 
     
     
         14 . The reciprocating saw of  claim 13 , wherein said insert includes a face that lies flush with a face of said mounting block. 
     
     
         15 . The reciprocating saw of  claim 12 , wherein said insert includes a tubular portion and said shim member extends within the insert tubular portion and at least part of said insert tubular portion fits over said drive shaft. 
     
     
         16 . The reciprocating saw of  claim 15 , wherein said insert tubular portion includes a shoulder that contacts a surface of said mounting block.