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. Inner and outer barrel type cylinder members are provided to define passages for conducting working fluid to the opposed expansible chambers and to conduct spent working fluid from one of the expansible chambers to a passage in the impact receiving member.
A hydraulic accumulator for use in a drill string having a fluid passage for supply of fluid to a hydraulic drill string tool is provided. The accumulator comprises a body provided with connecting means for connecting the accumulator to the drill string and an expansion chamber in fluid communication the fluid passage when the accumulator is connected to the drill string by the connecting means. The expansion chamber is expandable between a first volume and a second volume which is larger than the first volume. Further, the expansion chamber is provided with means for moving the expansion chamber from the first to the second volume upon a fluid pressure increase in the fluid passage and for moving the expansion chamber from the second to the first volume upon a pressure decrease in the fluid passage.
A hydraulic reciprocating piston hammer percussion drill includes an elongated piston hammer having opposed reduced diameter shank portions and disposed in a cylinder for reciprocating movement in response to pressure fluid acting continuously on one transverse face of the piston hammer and in response to valving of pressure fluid alternately to an opposed piston face of the piston hammer by a tubular sleeve valve which is disposed in sleeved relationship around the piston hammer between a piston portion of the piston hammer and an impact blow receiving bit. The tubular sleeve valve is provided with ports which communicate with high pressure and fluid exhaust ports in the piston hammer to effect reciprocation of the sleeve valve and of the piston hammer to deliver repeated impact blows to the bit. The bit may be configured to have a major portion of a transverse face disposed at an acute angle with respect to a plane normal to the bit and drill axis to allow directional drilling when the bit receives impact blows without being rotated. Retractable or fixed stabilizer or guide shoe members may be mounted on the exterior of the drill cylinder to aid in centering the drill in the drillhole or allow lateral deflection of the drill to accomplish directional drilling.
A hydraulic percussion drill includes a piston hammer disposed in a cylinder for reciprocating movement in response to pressure fluid acting continuously on one transverse face of the piston hammer and in response to valving of pressure fluid alternately to an opposed piston face of the piston hammer by a tubular sleeve valve disposed around the piston hammer. The drill includes a percussion bit configured to have a face portion disposed at an acute angle with respect to a plane normal to the bit and the drill central axis. Cooperating spiral splines on the bit and a bit chuck provide for directional drilling using a method which includes causing the bit to receive impact blows without rotating the cylinder housing to initiate a deviated drillhole.
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. The sleeve valve disposed between the piston hammer and the fronthead operates to vent pressure fluid from the forward chamber and the sleeve valve disposed between the piston hammer and the backhead effects valving of pressure fluid to both opposed chambers in the drill. The provision of the opposed sleeve valves and a central passage in the hammer for conducting pressure fluid to the forward end of the drill provides for a reduced diameter cylinder for slim hole and in-the-hole drilling operations.
A hydraulic reciprocating piston hammer percussion drill includes an elongated piston hammer having opposed reduced diameter shank portions and disposed in a cylinder for reciprocating movement in response to pressure fluid acting continuously on one transverse face of the piston hammer and in response to valving of pressure fluid alternately to an opposed piston face of the piston hammer by a tubular sleeve valve which is disposed in sleeved relationship around the piston hammer between a piston portion of the piston hammer and an impact blow receiving bit. The tubular sleeve valve is provided with ports which communicate with high pressure and fluid exhaust ports in the piston hammer to effect reciprocation of the sleeve valve and of the piston hammer to deliver repeated impact blows to the bit. The bit may be configured to have a major portion of a transverse face disposed at an acute angle with respect to a plane normal to the bit and drill axis to allow directional drilling when the bit receives impact blows without being rotated. Retractable or fixed stabilizer or guide shoe members may be mounted on the exterior of the drill cylinder to aid in centering the drill in the drillhole or allow lateral deflection of the drill to accomplish directional drilling.
