Portable hammer drill with rotating tool

A portable machine tool, such as a hammer drill, comprising housing means;

• a piston guided in said housing means for reciprocation in axial direction;
• a beater coaxial with said piston to be reciprocated by said piston during reciprocation of the latter, said housing means including a guide tube in which said piston and beater are guided for movement in axial direction, said piston and said beater having ends facing each other and being spaced in axial direction from each other, said facing ends defining in said guide tube an air pillow through which the striking energy produced by said piston during reciprocation thereof is transmitted to said beater;
• tool receiving means comprising a turning sleeve surrounding said beater and a holding bushing extending beyond said beater and fixedly connected to said turning sleeve for movement therewith, said turning sleeve surrounding said guide tube radially spaced therefrom, said holding bushing being formed with an axial bore therethrough having an open end facing said beater;
• a tool having a shaft extending through said bore towards said beater and having a free end for directly receiving the impact energy provided by the beater during reciprocation thereof, said tool shaft being guided in said bore for limited reciprocation in axial direction and held therein for rotation with said holding bushing;
• drive means in said housing means;
• first transmission means between said drive means and said piston for reciprocating the latter;
• and second transmission means between said drive means and said turning sleeve for rotating said turning sleeve, said second transmission means comprising a gear connected to that end of said turning sleeve which faces away from said holding bushing, and including an anti-friction bearing turnably supporting said turning sleeve at the region of said gear on said guide tube, and an O-ring surrounding said guide tube at that end of said anti-friction bearing which faces away from said gear for cushioning said bearing in axial direction.

A portable machine tool, such as a hammer drill, comprising housing means;

• a piston guided in said housing means for reciprocation in axial direction;
• a beater coaxial with said piston to be reciprocated by said piston during reciprocation of the latter;
• tool receiving means comprising a turning sleeve surrounding said beater and fixedly connected to said turning sleeve for movement therewith, said holding bushing being formed with an axial bore therethrough having an open end facing said beater, the outer diameter of the holding bushing being smaller than the outer diameter of said turning sleeve and a region of stepped transition being formed from said turning sleeve to said holding bushing;
• a tool having a shaft extending through said bore towards said beater and having a free end for directly receiving the impact energy provided by the beater during reciprocation thereof, said tool shaft being guided in said bore for limited reciprocation in axial direction and held therein for rotation with said holding bushing, said beater being provided at the end thereof facing said tool shaft with a coaxial beater bolt having a planar end face adapted to directly engage a corresponding end face on the free end of said shaft, the diameter of said beater bolt being slightly smaller than that of said bore through said holding bushing so that the beater bolt during its impact on said shaft end may move into said bore to be guided therein;
• catching means in said region of stepped transition from said turning sleeve to said holding bushing for catching the beater in its idle position in which the beater bolt extends into said bore;
• drive means in said housing means;
• first transmission means between said drive means and said piston for reciprocating the latter;
• and second transmission means between said drive means and said turning sleeve for rotating said turning sleeve.