Abstract: A twin hammer impact tool includes a hammer spindle, an inner ring hammer sleeved on the hammer spindle, an outer ring hammer disposed around the inner ring hammer, and rolling beads. The inner ring hammer has bead grooves each having a ball half-shape, and angularly spaced-apart hammer projections. The inner ring hammer is reciprocally movable relative to the hammer spindle while rotating together with the hammer spindle. The outer ring hammer has guiding grooves. The bead grooves respectively face and open toward the guiding grooves. Each rolling bead is received within one of the bead grooves and one of the guiding grooves. An output hammer has angularly spaced engagement projections to engage the hammer projections.

Abstract: A twin hammer impact tool includes a hammer spindle, an inner ring hammer sleeved on the hammer spindle, an outer ring hammer disposed around the inner ring hammer, and rolling beads. The inner ring hammer has bead grooves each having a ball half-shape, and angularly spaced-apart hammer projections. The inner ring hammer is reciprocally movable relative to the hammer spindle while rotating together with the hammer spindle. The outer ring hammer has guiding grooves. The bead grooves respectively face and open toward the guiding grooves. Each rolling bead is received within one of the bead grooves and one of the guiding grooves. An output hammer has angularly spaced engagement projections to engage the hammer projections.

Abstract: A grease output device for an electrical grease gun has a body, a double-cam member and a driving member. The body has a holder and a seat mounted with the holder. The double-cam member connects to the body and has a driven unit and a driving unit. The driven unit has a driven gear and two cams misaligning with the driven gear. The driving gear has two rings mounted around the cams and two pistol rods connecting to the rings. The driving unit has a driving gear engaging with the driven gear. The driving member connects to the body to rotate the driving gear so the driven gear is rotated to push the rings. Hence, the grease can flow out of the body successively by the pistol two pistol rods moving back and forth alternatively.

Abstract: A grease output device for an electrical grease gun has a body, a double-cam member and a driving member. The body has a holder and a seat mounted with the holder. The double-cam member connects to the body and has a driven unit and a driving unit. The driven unit has a driven gear and two cams misaligning with the driven gear. The driving gear has two rings mounted around the cams and two pistol rods connecting to the rings. The driving unit has a driving gear engaging with the driven gear. The driving member connects to the body to rotate the driving gear so the driven gear is rotated to push the rings. Hence, the grease can flow out of the body successively by the pistol two pistol rods moving back and forth alternatively.

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.