Patent ID: 8622152

Claim:
A down-the-hole drill hammer comprising: a housing; a backhead at a proximal end of the housing, the backhead including: a distal end, a threaded male proximal end, a supply inlet for receiving a supply of working fluid to an interior of the backhead, and an exhaust port for communicating between the interior of the backhead and an exterior of the backhead; and a tubular sliding check valve assembly within the housing proximate to the backhead, the sliding check valve assembly including: a distributor having: a central opening, an aperture extending through the distributor and offset from the central opening for allowing the passage of working fluid through the distributor, and an exhaust gallery for communicating between the central opening and the exhaust port, and a sliding valve slidable along the central opening and movable between a closed position and an open position, the sliding valve including: a closed proximal end, an open distal end, and an opening about a midsection of the sliding valve, and a biasing member biasing the sliding valve, wherein, in the closed position, the proximal end of the sliding valve sealingly engages the supply inlet and a distal end of the sliding valve sealingly engages an inlet opening of the exhaust gallery, and wherein, in the open position, the sliding valve is offset from the supply inlet, the openings of the sliding valve are in communication with the exhaust gallery, and the supply inlet is in communication with the aperture extending through the distributor.