| 摘要 |
An open end reversible ratchet wrench has only two pawls, only one of which is engaged with the ratchet at any one time. In a first embodiment, two multitooth pawls are pivoted on a common pivot pin. The design and spacing of the pawl teeth and the location of the pivot pin make it possible to use pawls with at least three and no more than four pawl teeth. For every rotational position of the jaw, at least one pawl tooth is engagable with the ratchet irregardless of the position of the slot. The pawls are biased towards engagement with the ratchet. A reversing switch operates a cam to select clockwise rotation of the jaw, counterclockwise rotation thereof or a neutral mode in which the jaw rotates freely without ratcheting to facilitate easy removable of the wrench. The position of the reversing switch is latched by a detent ball cooperating with locking notches on the casing. In a second embodiment, the pawls are pivoted on separate pivot pins on opposite sides of the head and extend crosswise to engage the rachet on the opposite side of the head. The selection means includes a pulley and cables to move the pawls to and from engagement with the rachet. A retention collar on the pulley has three flat surfaces which cooperate with a flat spring to retain the pulley in a selected position. In a third embodiment, a pair of pawls reciprocate along guide paths parallel to the longitudinal axis of the wrench. A single control includes a linkage for moving the pawls to and from engagement with the ratchet.
|
