| 摘要 |
<p>A motor driven hand tool such as a hammer drill incorporates an overload clutch, for minimising the idling torque transmitted to its handle should the working tool jam, comprising two disc-shaped drive parts (2, 3) mounted on a shaft 1, the drive part (3) having a cage (5) retaining balls (4), at different radial spacings relative to the centre of the shaft (1), which register with respective detent openings (14) on the drive part (2). In the event of a predetermined torque being exceeded, the balls (4) move out of the detent openings (14) to move the drive parts (2, 3) apart against the action of compression spring (9) uncoupling the clutch and thereby allowing the drive parts (2, 3) to rotate freely relative to each other subject only to the rolling friction of the balls which are also at different angular spacings so that they reengage the detent openings only once per revolution. <IMAGE></p> |
