Patent ID: 7032713

Claim:
A battery operated grease gun comprising: a housing having a handle; a motor drive assembly mounted in the housing and comprising a motor having a drive shaft having an angular speed and torque; a battery pack electrically connected to the motor; a switch electrically connected between the motor and the battery pack; and an electronic pressure regulator having an adjustment knob and a control box having a adjustment shaft and a circuit electrically connected to the motor and the battery pack, and the adjustment shaft extending out of the housing to which the adjustment knob is attached; a gear housing mounted in the housing and having a top, a bottom, a top recess defined through the top of the gear housing, a bottom recess defined through the bottom of the gear housing, a countersunk through hole communicating with the top recess and the bottom recess and a bearing mounted in the countersunk through hole; a planetary gear assembly mounted in the bottom recess of the gear housing and coupled to the drive shaft of the motor to reduce angular speed and torque of the drive shaft; a pump assembly mounted in the housing and comprising a main body having a cylindrical skirt and a gear housing cap with a longitudinal through hole, the cylindrical skirt mounted outside the housing and having a grease passage with an outside opening, and the gear housing cap mounted in the housing and covering the gear housing; a discharge spout mounted and held in the outside opening of the grease passage; a sliding block slidably mounted in the top recess of the gear housing and having a transverse cam slot with a top and a bottom; a drive pin slidably mounted in the transverse cam slot to move the sliding block reciprocally and having a top faceted end and a bottom faceted end extending respectively out of the top and bottom of the transverse cam slot; an upper drive disk having an upper central shaft rotatably mounted in the through hole of the gear housing cap over the sliding block and having an upper faceted hole formed eccentrically in the upper drive disk and holding the top faceted end of the drive pin; and a lower drive disk mounted rotatably in the countersunk through hole under the sliding block, and having a bottom face, a lower faceted hole formed eccentrically in the lower drive disk and holding the bottom faceted end of the drive pin, and a lower central shaft mounted through the drive bearing in the countersunk through hole and has a proximal end formed integrally with and extending from the bottom face and a distal end that is faceted and coupled to the planetary gear assembly; a plunger attached to the sliding block and having an outside end attached to the sliding block and an inside end passing through and being held in the grease passage; and a cylindrical lubricant reservoir attached to the cylindrical skirt for lubricant will enter the grease passage.