US Patent 8622152 Down-the-hole drill hammer having a sliding exhaust check valve

A down-the-hole drill hammer having a housing, a backhead and a tubular sliding check valve assembly that includes a distal end, a threaded male proximal end, a supply inlet and an exhaust port. The exhaust port communicates between an interior of the backhead and an exterior of the backhead. The tubular sliding check valve assembly includes a distributor, a sliding valve, and a biasing member. The distributor has a central opening extending through the distributor, an aperture extending through the distributor, and an exhaust gallery. The sliding valve is slidable along the central opening. The biasing member biases the sliding valve to a closed position.