| 摘要 |
<p>A reciprocating pneumatic motor for rock drills and the like wherein a freely-movable hammer piston repeatedly strikes the end of a drill rod, usually a rotating drill rod. Fluid under pressure enters a single, central inlet port in the wall of a cylinder which houses the piston with alternate cycling ports being incorporated into the piston itself. A muffler for receiving exhaust gas surrounds the cylinder and includes an annular wall of resilient material; annular spacers separating the wall from the cylinder, the spacers having openings through which the exhaust gas can pass; and an opening in the annular wall through which exhaust gas, after passing through the spacer openings, can pass to the atmosphere.</p> |
