Patent ID: 7267198

Claim:
A portable electrical grease gun comprising a grease barrel, a handle, a crank link mechanism, a piston, a microswitch, a gearbox, a gear reduction mechanism and a D.C. motor, wherein: a) said gear reduction mechanism is disposed in said gearbox, two ends of the gear reduction mechanism being operably connected to an output shaft of said D.C. motor and a crank of said crank link mechanism, respectively; b) said piston is provided above said gearbox and reciprocates in a passage of the gearbox, one end of the piston being connected to said crank link mechanism; c) said gearbox is provided with an air release valve, a grease filling valve, a grease discharge valve, and a grease outlet pipe spaced apart on said gearbox and fluidly communicating with each other and the passage where the piston reciprocates via the gearbox; d) said handle is connected to the gearbox and is provided with a battery pack and an on-off button which is operably connected to said microswitch; and e) said grease barrel is connected to the gearbox and provides a supply of grease into the gearbox; and wherein said crank link mechanism comprises: the crank, a driving link with its first end pivotally connected to the crank, a transmission link with its first end pivotally connected to a second end of the driving link, and a driven link with its first end pivotally connected to a second end of the transmission link and a second end of the driven link being connected to the gearbox; and wherein said end of the piston is pivotally connected to said transmission link at a point between pivotal connections of the first end and the second end of the transmission link with the driving link and the driven link.