Patent ID: 7252154

Claim:
A percussion device having means for providing a stress pulse in a tool connected to the percussion device, wherein said means for providing a stress pulse include: an energy storing space, which is located in the body of the percussion device and limited by the body of the percussion device and a separate transmission element located movably in the axial direction of the tool with respect to the body of the percussion device, the energy storing space being filled with elastic and reversible, compressible energy storing material, wherein the energy storing material is liquid, means for bringing the energy storing material to stress state by increasing its pressure so that when the energy storing material is in a desired state of stress, the transmission element is in a position with respect to the body of the percussion device, from which position the transmission element can move with respect to the body of the percussion device towards the tool, and means for releasing the transmission element abruptly to move towards the tool, whereby the energy stored in the energy storing material is discharged as a stress pulse via the transmission element to the tool that is directly or indirectly in contact therewith.