Patent ID: 8424614

Claim:
A hydraulic hammer comprising: a housing with a cylinder bore and a guide sleeve for a working implement, a reciprocating hammer piston reciprocated in the cylinder bore, and a distribution valve for directing pressure fluid to the hammer piston, wherein said distribution valve comprises: a valve bore with a pressure fluid inlet communicating with the pressure fluid source and a pressure fluid outlet communicating with one drive side of the hammer piston, and a valve element sealingly guided in the valve bore for controlling a flow of pressure fluid between said inlet and said outlet, wherein said distribution valve includes: a primary seal means including an axially facing valve seat in said valve bore and a contact surface on said valve element for sealing contact with said valve seat, and a secondary seal means including a cylindrical envelope surface on said valve element for clearance sealing relative to said valve bore, and wherein said primary and secondary seal means are arranged in series to seal off pressure fluid communication between said inlet and said outlet.