Cam-driven pump mechanism for a battery-powered grease gun

Abstract

A cam-driven pump mechanism for a battery-powered grease gun includes a cam driver and a cam-driven pump. The grease gun has a transition body having a grease channel and a casing having an inner chamber. The cam driver is mounted in the inner chamber. The cam-driven pump has a cylindrical cam, a sliding block, a follower and a piston. The cylindrical cam is rotatably mounted in the inner chamber, is rotated by the cam driver and has an eccentric annular groove. The sliding block is slidably mounted in the casing. The follower is securely attached to the sliding block and mounted slidably in the eccentric annular groove. The piston is mounted slidably in the grease channel and connects to the sliding block. Consequently, use of the cylindrical cam prevents localized friction on the sliding block and keeps the pump mechanism from wearing excessively.

1 . A cam-driven pump mechanism for a battery-powered grease gun having a body with a casing with an inner chamber and a discharge assembly with a transition body having a grease channel aligned and communicating with the inner chamber, and the cam-driven pump mechanism comprising: 
 a cam driver adapted to be mounted in the inner chamber; and    a cam-driven pump driven by the cam driver and the cam-driven pump comprising 
 a cylindrical cam adapted to be rotatably mounted in the inner chamber, rotated by the cam driver and having an outside surface and an eccentric annular groove formed in the outside surface;  
 a follower mounted slidably in and driven by the eccentric annular groove in the cylindrical cam;  
 a sliding block adapted to be mounted slidably in the inner chamber, attached securely to the follower and driven by the follower; and  
 a piston attached to the sliding block, adapted to be mounted slidably in the grease channel and driven up and down in the grease channel by the sliding block.  
   
   
   
       2 . The cam-driven pump mechanism as claimed in  claim 1 , wherein the cam driver comprises 
 a planetary gear assembly comprises 
 a gear housing adapted to be mounted in the casing; and  
 a set of planetary gears mounted in the gear housing and connected to the cylindrical cam; and  
   a motor attached to the gear housing and connected to and rotating the set of planetary gears to rotate the cylindrical cam.    
   
   
       3 . The cam-driven pump mechanism as claimed in  claim 2 , wherein 
 the cylindrical cam further has a rectangular drive shaft connected to the set of planetary gears;    the sliding block has a follower hole in which the follower is securely attached and a piston slot; and    the piston has an annular groove engaging with the piston slot.    
   
   
       4 . The cam-driven pump mechanism as claimed in  claim 3 , further comprising a bushing mounted around the follower and mounted slidably in the eccentric annular groove in the cylindrical cam.