Abstract: A pneumatic motor for rock drills and the like having a reciprocating piston with valves at its opposite ends for valving motive air to the piston head from both ends of the cylinder. Large receivers are provided near the respective valves to accommodate availability of air on demand from the valves and to dampen pressure fluctuations. One of the receivers is connected to an external source of fluid under pressure; while the two receivers are interconnected by tubing external to the pneumatic motor itself. This permits the cylinder for the piston to comprise a simple tube provided with exhaust ports only. Additionally, exhaust air and oil from an air motor, which rotates the rock drill, are directed into the area between the lower end of the reciprocating piston and a striking bar for the drill rod to lubricate the reciprocating parts.

Abstract: A drill motor rigid enclosure is provided for a rock drill motor. The drill motor is encompassed within the enclosure such that viration, torque, and thrust produced by the motor is isolated from the rigid enclosure, therefore noise reduction of the drill motor is achieved.

Abstract: A dual bushing centralizer is provided for a rock drill. The one bushing is provided for stabilizing the rock bit and a second bushing is provided which stabilizes the drill rod. An elastomeric stinger encapsulates both bushings and also provides a noise reduction seal around the drilled hole.

Abstract: A pneumatic motor for rock drills and the like having a reciprocating piston with valves at its opposite ends for valving motive air to the piston head from both ends of the cylinder. Large receivers are provided near the respective valves to accommodate availability of air on demand from the valves and to dampen pressure fluctuations. One of the receivers is connected to an external source of fluid under pressure; while the two receivers are interconnected by tubing external to the pneumatic motor itself. This permits the cylinder for the piston to comprise a simple tube provided with exhaust ports only. Additionally, exhaust air and oil from an air motor, which rotates the rock drill, are directed into the area between the lower end of the reciprocating piston and a striking bar for the drill rod to lubricate the reciprocating parts.

Abstract: This invention relates to improvements in working member assemblies and is described hereinbelow with particular reference to a novel striking bar assembly for use in open front type rock drills.

Abstract: A drilling apparatus including improved means for drill string manipulation for effecting an improved method of drill steel breakout and disassembly.This is a continuation, division, of application Ser. No. 712,622, filed Aug. 9, 1976.

Abstract: This invention relates generally to improved means for securing a working member within a rotary tool and is described hereinbelow with particular reference to a percussively actuatable striking bar secured by the novel securing means hereof within a percussive rock drilling apparatus.

Abstract: A drilling apparatus adapted to have a drill string releasably secured thereto and including improved means for selectively locking such a drill string against axial rotation.

Abstract: Improved clamping or gripping means particularly for gripping an elongated formed member.

Abstract: An improved fluid operated rock drill apparatus having all fluid connections thereto secured to the yoke of the drill assembly by a unitary connector means. The yoke is centrally located so that the high pressure fluid being directed to the rock drill hammer piston flows through a path of reduced length resulting in a more efficient operation.

Abstract: A fluid operated reciprocating piston rock drill wherein the piston has a stem portion closely slidably received in a guide bushing and the cylinder of the rock drill provides clearance space around the head of the piston.

Abstract: A drill steel of the type employed in rock drilling and more particularly a drill steel having improved stress distribution and relief means.

Abstract: A rock hammer and more particularly a rock hammer having thereon improved means for securing a cutting or breaking bit assembly thereto.

Abstract: An automatic control system for an adjustable, power operated drill string centralizer.