BOHRHAMMER

摘要

A hammer drill is provided with a clutch whose movable part is firmly connected to an axially displaceable drum which supports a wobbling disc driving a percussive mechanism for striking a work tool. The axially fixed clutch part is rotated by driving motor and is backed-up by a housing of the drill. Retroacting forces from the percussive mechanism are transferred via the drum onto the movable clutch part so that the engagement of the clutch is reinforced at the moment when the compression generated by percussive mechanism is maximum. When pressure applied on work tool is relieved, a separating spring disengages the clutch and braking surfaces on the drum limit its axial displacement and brake the rotation of the wobbling disc.