| 摘要 |
<p>A pneumatically operated fastener driving device (10) includes a pilot pressure operated main valve (44) movable from a normally closed position into an opened position allowing a supply of air under pressure to initiate and effect the movement of a fastener driving element (28) through a fastener drive stroke. A secondary valve member (90) is mounted so as to be movable between an open position permitting communication between a pilot pressure chamber (78) and an exhaust port (86) and a closed position preventing communication between the pilot pressure chamber (78) and the exhaust port (86). The secondary valve member (90) permits one full cycle of operation to be performed while a trigger member (136) remains actuated, thereby minimizing exposure of the fastener driving element (28) and thus damage thereto.</p> |
