| 摘要 |
A hand-held power tool with improved means for inhibiting uncalled-for rotation of the output shaft that is relatively long-lived and self-compensating for wear. The tool comprises a housing, a braking member fixedly mounted in the housing and an output shaft mounted in the housing for rotation. The output shaft has an outer end portion projecting out from the housing for reception of an attachment for the tool. A ratchet wheel on the output shaft is adapted to be driven in one direction or the other. The ratchet wheel has a side face facing a first surface of a wear member (e.g., washer) and a plurality of recesses extending inward from the side face spaced at intervals. The wear member is keyed to the output shaft for conjoint rotation with the shaft. A plurality of engagement members, or more preferably coil compression springs and cylindrical pins, are received one in each recess and biased outward from the recesses, against the first surface of the wear member to bias a second surface of the wear member, opposite said first surface, against the braking member for holding the ratchet wheel against rotation in a direction opposite the driven direction of rotation.
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