Abstract: A hydraulic reciprocating percussion tool, particularly adapted for drilling applications, comprises an elongated cylinder, opposed fronthead and backhead members and a central bore in the cylinder for supporting a reciprocating piston hammer. The piston hammer has reduced diameter end portions which have respective tubular sleeve valves disposed in sleeved relationship thereon and engageable with valve retainer members on the reduced diameter portions for effecting movement of the valves with the piston hammer. The head members include tubular sleevelike stem portions which cooperate with the respective valves to valve pressure fluid to and from opposed chambers in the cylinder to effect repeated impact blow delivering strokes to a shank member disposed in a chuck connected to the fronthead.

Abstract: A pressure-driven engine is provided therein with an intake valve and an exhaust valve the opening and closing operations of which are controlled by a combination of the urging force of the respective springs and the attractive force of the respective magnets. The engine automatically repeats reciprocating motion merely by supplying a pressure source such as steam or various kinds of compression gas. The reciprocating motion or the rotational motion converted from the reciprocating motion is utilized as a power.

Abstract: A hydraulic in-the-hole type percussion tool including an elongated piston-hammer which is disposed for delivering percussion blows to an impact receiving bit or shank member and is adapted to reset an elongated tubular sleeve type distributing valve disposed in the tool cylinder rearwardly of the piston-hammer. The distributing valve is moved in one direction by the piston-hammer and is urged in the opposite direction by pressure fluid which is transferred to a chamber to act on a pressure surface of the distributing valve when the piston-hammer uncovers a fluid transfer port. An in-line hydraulic accumulator is disposed between the percussion mechanism and a source of working fluid and includes an annular piston forming an accumulator chamber and biased by a series of conical washer type springs. The tool is adapted to use high pressure water or drilling mud as the working fluid and which is conducted to and from opposed expansible chambers formed in an inner cylinder member.

Abstract: A reciprocable device comprising a reciprocable member mounted for reciprocating movement within a chamber and a valve system for controlling the supply of fluid under pressure to the reciprocable member to bring about reciprocation of such member. A motor is enabled by the reciprocable member to operate the valve system whereby at least some of the force for driving the valve system is obtained from the motor and not from the reciprocable member.