| 摘要 |
<p>A pneumatic torque impulse wrench comprises a housing (10), a motor (15), a hydraulic impulse unit (20) including an inertia drive member (21) and intermittently coupling the motor (15) to an output shaft (18), a shut-off valve (23) controlling the pressure air supply to the motor (15), and an activating mechanism (25) arranged to shift the shut-off valve (23) from a fully open position to a closed position via one or more partly closed positions. An activating mechanism (25) for shifting the shut-off valve (23) comprises a retardation responsive inertia element (28) movably supported on the inertia drive member (21), and a trip element (24) displaceable by the inertia element (28) and arranged to initially support the shut-off valve (23) in a fully open position during a screw joint tightening process and in succeeding one or more partly open positions for obtaining a power reduction of the motor (15) when approaching a target torque level.</p> |
