| 摘要 |
An hydraulic rock drill having an hydraulically reciprocable hammer piston arranged to pound an anvil carrying a drill string. A sleeve type shiftable valve periodically engaged by the piston to effect alternate application to and relief of pressurized hydraulic fluid from the piston cylinder to reciprocate the piston. A constant supply of pressurized hydraulic fluid to actuate the piston is provided by a surrounding reservoir. Hydraulic feed means responds to a predetermined displacement of the anvil relative to the housing to feed the housing relative to the work in accordance with the progress of the anvil. Hydraulic means serves to cushion rebounding actions of the anvil; and means is provided to apply cooling fluid to the sliding surfaces of the tool during its operation.
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