Abstract: A compressor piston divides a first compartment into two compression chambers, while a hammer piston divides a second compartment into two drive chambers, each of the compression chambers being connected to a respective one of the drive chambers to form a closed fluid system wherein reciprocation of the compressor piston causes cyclic compression and expansion of the fluid in the compression chambers and thus in the drive chambers, to effect a cyclic impacting of the hammer piston with a bit adapter connected to the drill bit. A mud motor rotates a shaft to drive an oscillator which reciprocates the compressor piston. The oscillator can comprise roller elements in the compressor piston in engagement with canted grooves in the shaft. While drilling mud drives the motor and then passes downwardly to flush the drill bit and the borehole, the drilling mud is isolated from the closed fluid system.

Abstract: A compressor piston divides a first compartment into two compression chambers, while a hammer piston divides a second compartment into two drive chambers, each of the compression chambers being connected to a respective one of the drive chambers to form a closed fluid system wherein reciprocation of the compressor piston-causes cyclic compression and expansion of the fluid in the compression chambers and thus in the drive chambers, to effect a cyclic impacting of the hammer piston with a bit adapter connected to the drill bit. A mud motor rotates a shaft to drive an oscillator which reciprocates the compressor piston. The oscillator can comprise roller elements in the compressor piston in engagement with canted grooves in the shaft. While drilling mud drives the motor and then passes downwardly to flush the drill bit and the borehole, the drilling mud is isolated from the closed fluid system.

Abstract: A cluster drill includes a first plate portion and a second plate portion. The first plate portion extends parallel to the second plate portion and is rigidly affixed to the second plate portion. At least one first and second plate aperture is formed in the first and second plate, respectively. At least one modular retainer unit, to be mounted within the first and second plate apertures, retains a first and second portion of a rock drill apparatus. A cannister affixes the first plate portion relative to the second plate portion. The cannister may be either cylindrical or contain protuberances to accommodate the modular retainer unit. A drill bit lock restricts motion between the a drill bit and the second plate when desired.

Abstract: A quick detach bit apparatus includes a wear sleeve having a chuck threaded thereinto. A bit is mounted within the chuck. The bit and chuck are interconnected by mating, axially extending splines and grooves. The chuck includes a resiliently mounted segment urged into engagement with the bit. A quick release tool is accommodated in a passage between the bit and chuck. The tool is inserted into the passage and has a thickness sufficient to urge the segment out of engagement with the bit so that the bit is removed from the chuck.

Abstract: Disclosed is a new method of construction for multiple or gang down hole rock drills. A rigid mounting cylinder with alignment and securing means for the individual drills is provided. The cylinder further serves to attach the multiple drills to a single drill string which supplies air to the individual drills. The cylinder further facilitates rock chip removal by filling all but the peripheral annulus which forms the exit channel for exhaust air.

Abstract: This invention pertains to a hydraulic reciprocating device having a housing and a piston in the housing. The piston has a first and second surface, and a means for intermittently communicating the first surface of the piston with a hydraulic pressure source. Also provided is a means for continuously communicating the second surface of the piston with pressurized fluid such as pneumatic fluid. The piston moves in a first direction when the hydraulic pressure source communicates with the first surface of the piston and the piston moves in a second direction when the hydraulic pressure source does not communicate with the first surface of the piston.