ROTARY HAMMER

摘要

A rotary hammer and a power tool. The rotary hammer is operable in an idle mode and a hammer mode and comprises a housing 14 and a barrel 50 positioned in the housing and having a forward portion. A ram 78 is positioned within the barrel and is movable relative to the barrel between hammering positions and an idle position. In some aspects, a ram catcher assembly 110 is positioned along the axis adjacent the forward portion of the barrel to releasably hold the ram 78 in the idle position. The ram catcher 110 assembly includes a friction member 114 frictionally engageable with the ram and a damping member 118 at least partially surrounding the friction member. As the ram moves to the idle position with a force, the damping member absorbs at least a portion of the force and the friction member 114 applies friction to the ram. Also disclosed is a ventilated crank case, an air cooled damping member 116, a chuck configuration using a transverse pin 146, and an air cushion for the ram as its enters the idle position.