| 摘要 |
A pneumatic percussion tool for rock breaking and other purposes having removably enclosed within an outer casing a pneumatic engine including a cylinder with a work head extending slidably from its lower end, a piston slidable in the cylinder impacting the work head on its downstroke. The piston serves also as a sliding valve into which compressed air is admitted through an air inlet tube fixed coaxially in the cylinder and on which the piston is slidable. The piston and cylinder are formed with such air ports and passages that the engine remains at rest until the work head applied with pressure to a work-piece is retracted into the cylinder displacing the piston valve which thereupon is reciprocated, causing the work head to deliver percussive blows while applied to the work-piece. At the final part of its upstroke, the piston enters a compression chamber or energy cell which thus decelerates the piston and commences its downstroke.
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