Patent ID: 8235136

Claim:
A drilling and/or impact hammer, comprising: a pneumatic spring percussion mechanism having a drive piston that is capable of being moved back and forth, and having a percussion piston that is capable of being driven by the drive piston, a hollow space for accommodating an air spring being formed between the drive piston and the percussion piston; a no-load channel for connecting the hollow space to the surrounding environment of the pneumatic spring percussion mechanism and for ventilating the hollow space in a no-load operating state; a valve that is situated in the no-load channel for opening the no-load channel in the no-load operating state and for closing the no-load channel in a percussion operating state; an acquisition device for acquiring a control quantity that distinguishes percussion operation and no-load operation; the valve being capable of being opened and closed dependent on the control quantity, and for this purpose assuming a position corresponding to the control quantity; and a delay device via which the valve is capable of being controlled during closing in such a way that it reaches the position corresponding to the acquired control quantity with a time delay, and wherein the time delay is dimensioned such that it extends over a time span of several impact cycles, each comprising a back-and-forth movement of the drive piston.