Abstract: A safety throttle is provided for a hand held pneumatic tool in which a pivotable intermediate member must be manually moved, by a prior secondary movement, into a slotted throttle lever before the later primary movement of the throttle lever will allow the intermediate member to activate a throttle valve to actuate the pneumatic tool.

Abstract: A rock drill having a hydraulic pressure reservoir formed by the drill housing, and an anvil rotation mechanism enclosed in the housing. A piston of substantial length and a mechanical hydro-operated valve means, provide favorable pulse duration and low impact velocity. The piston has only two sliding seal diameters which permits simplified valve and cylinder configuration. The friction surfaces of the fronthead drill assembly are lubricated and cooled by integration with the circulating hydraulic system. A floating seal cartridge between the piston and anvil, tends to rotate the piston with the anvil to minimize rotative scrubbing at impact.