| 摘要 |
<p>A pneumatically driven, fastener-driving tool (10), has a housing structure (12) with an upper chamber (16), and a tubular cylinder (30) mounted within it. A driving piston (40) is movable axially within the cylinder (30), between an upper position and a lower position, and a valve member (50) is movable axially within the housing structure (12), above the cylinder (30), between an upper position and a lower position. The valve member (50) has an upper surface facing the upper chamber (16). A sealing member (80) is arranged to provide a seal between the sealing member (80) and the valve member (50) under certain conditions and to provide seal between the sealing member (80) and the cylinder (30) under other conditions. An annular, elastomeric member (100) located within the upper chamber (16) of the housing structure (12) is engaged with the lower surface (18) of the upper portion (14) of the housing structure (12) and with the upper surface of the valve member (50) for biasing the valve member (50) downwards to its lower position, for permitting the valve member to be upwardly moved to its upper position, and for functioning as a bumper between the valve member (50) and the upper portion (14) of the housing structure (12) when the valve member (50) moves upwards. <IMAGE></p> |
