Ratchet wrench.

摘要

A powered ratchet wrench (10) is constructed of several components. A throttle lever (20) controls air flow to a rotary air motor (30). The rotary output of the motor is transmitted to a hammer assembly (40) of an impact clutch mechanism. A spring (50) biasses an anvil shaft (60) into association with the hammer assembly (40). The anvil can be directly driven by the motor through the hammer assembly or can be driven intermittently by a series of rotational impacts from the hammer assembly. The rotation of the anvil shaft causes the reversible ratchet mechanism (70) to rotate in the desired direction, thus tightening or removing a threaded fastener. Only a small reaction force is transmitted by the tool to the operator once the fastener is tightened.