Patent attributes
The machine tool includes a pneumatic percussion mechanism having a cup-shaped exciter cylinder (21) with an inner chamber (31) which is open in the direction of impact (26), and a free piston (22) which is movable in the inner chamber (31). A recess (32) and at least one ventilation opening (35), spaced at a distance from the recess (32) in the direction of impact (26), are provided in a shell-type wall (39) of the inner chamber (31). The free piston (22) includes a sealing element (53) which seals off the at least one ventilation opening (35) when the sealing element (53) is oppositely situated from the at least one ventilation opening (35), and which in the region of the recess (32) is separated at a distance from the shell-type wall (39) when the sealing element (53) is oppositely situated from the recess.