Patent ID: 8672051

Claim:
An electric hammer comprising: a rear housing; a cylindrical barrel coupled to the rear housing, the cylindrical barrel having a rear part and a front part; a motor located in the rear part of the cylindrical barrel, a tool holder including at a tip end thereof a mount portion for a bit, the tool holder being coaxially and rotatably held in a front part of the cylindrical barrel; and able to move in a longitudinal direction a striking mechanism located in the rear part of the cylindrical barrel that strikes the bit by driving the motor a change ring disposed between the mount portion and the tool holder, the change ring being capable of rotating together with the tool holder and moving in a longitudinal direction and whose rotation and longitudinal movement are controllable from outside, a lock ring located between the change ring and the cylindrical barrel which engages the change ring at a rearward position of the change ring to restrict the rotation of the change ring a cylindrical front cover mounted on and covering a front part of the cylindrical barrel a cylindrical rear cover mounted on and covering the rear part of the cylindrical barrel, the cylindrical rear cover being assembled to the rear housing wherein a ridge is provided in one of an outer surface of the cylindrical barrel and an inner surface of the cylindrical front cover the ridge extending rearward from the front end of the cylindrical barrel, and a groove defined by one of the outer surface and the inner surface into which the ridge is fitted to substantially prevent rotation of the front cover with respect to the barrel the inner surface of the cylindrical front cover defining a latch portion between the mount portion and the ridge at a peripheral edge of the lock ring, wherein the latch portion is structured to restrict forward movement of the front cover.