it is forced to execute a periodic linear movement an air cushion formed by a pneumatic chamber 15 between the exciter 11 and the striker 12 couples a movement of the striker 12 to the movement of the exciter 11 the striker 12 can strike a rear end of the drill chisel 4 directly or else indirectly via an essentially stationary intermediate striker 16 and can transmit part of its pulse to the drill chisel 4 the striking mechanism 6 and preferably the other drive components are arranged inside a machine housing 17 the drive shaft 7 is coupled to the motor 5 via a gear 18 and a slip clutch 19 the slip clutch 19 is actuated when the torque that is present on the drive shaft 7 exceeds a threshold value for example when the drill chisel 4 is blocked the slip clutch 19 shown by way of example has a hollow gear wheel 20 on the drive side and a bevel gear 21 on the driven side fig2 the slip clutch 19 is inserted into the hollow gear wheel 20 and couples the hollow gear wheel 20 to a shaft 22 of the bevel gear 21 the drive side 20 has an annular running surface 23 that is arranged coaxially to the shaft 22 the running surface 23 has cams 24 projecting radially inwards as seen in the direction of rotation 25 the cams 24 have a front flank 27 as well as a rear flank 26 the.