Patent ID: 7762350

Claim:
Impulse generator for a rock breaking tool, the impulse generator ( 2 ) comprising a propulsion chamber ( 6 ) for receiving a pressurizable liquid volume ( 8 ), and an impulse piston ( 10 ) received in the propulsion chamber ( 6 ), wherein the impulse piston ( 10 ) is arranged for transfer of pressure peaks in the liquid volume ( 8 ) into impulses in the tool ( 12 ), and at least one propulsion mechanism ( 14 ) comprising a piston ( 16 , 22 , 30 , 34 ) arranged movable within the propulsion chamber ( 6 ) for volume reduction of the propulsion chamber ( 6 ) and thereby volume reduction of the pressurizable liquid contained in the propulsion chamber ( 6 ) so as to generate a pressure peak in said pressurizable liquid, whereby transfer of energy into impulses in the tool ( 12 ) is effected by the impulse piston ( 10 ) being driven forward by said pressure peak in said pressurizable liquid in the propulsion chamber ( 6 ).