Abstract: An apparatus for mechanically handling drilling equipment comprising at least drill pipes and a drill bit and drill guide bushing has a carrier. A clamp on the carrier clamps a first drill pipe unrotatably relative to the carrier in a drill-pipe position. An opener is spaced from the clamping axially of the first drill pipe when the first drill pipe is clamped in the drill-pipe position, the opener being pivoted on a first pivot that is spaced from and parallel to the first drill pipe when the first drill pipe is clamped in the drill-pipe for pivoting to an opener position at a second drill pipe that is axially thread-connected onto the first drill pipe and withdrawal therefrom. A first power device so pivots the opener.

Abstract: A drill pipe carousel is pivotal within a drilling mast between retracted and operating positions. The carousel contains a plurality of drill pipe receptacles for holding sections of drill pipe. Each of these drill pipe receptacles includes an upper and lower set of clamps that selectively clamp around a section of drill pipe within the receptacle to retain it in place, and open to release the pipe section. In the carousel operating position, a section of drill pipe is in alignment with the drill hole and a rotary head mounted on the drilling mast for linear movement along the mast. The rotary head attaches to this drill pipe section and rotates it to drill into the drill hole as the rotary head moves along the mast.

Abstract: A drill pipe bushing for stabilizing the drill pipe at the mouth of the well during drilling includes a plurality of support arms supported in a circular array about the drill pipe. Rollers are attached to each support arm with the axis of the rollers normally parallel to the axis of the drill pipe. The support arms move the rollers into engagement with or away from the drill pipe. The rotational axis of the rollers become canted upon both rotation and translation of the drill pipe through the drill pipe bushing during the drilling operation.

Abstract: A drive system for a hoist-pulldown linkage of a blast hole drill employs a variable speed electric motor and a variable ratio coupling between the motor and the hoist-pulldown linkage. A first regulator actuates the electric motor for high torque operation when the ratio of the coupling is low. A second regulator means activates the electric motor for low torque operation when the ratio of the coupling is high. Transfer in coupling ratio is coordinated with change between regulators. The first regulator means is a voltage regulator with a current spillover limit. The second regulator is a voltage regulator with an adjustable pulldown force limit with means to select the rotational speed reference of the motor.