| 摘要 |
An expandable bit screw holding screwdriver comprising: an elongated shank having a handle end and a blade end; and, a slide coaxially mounted on the shank, is disclosed. The blade end is formed by the tips of a pair of shank elements movable between a position whereat the elements diverge outwardly in their facing plane and a position whereat the elements diverge less and may become generally aligned. Intermediate the handle end and the blade end, the shank includes a helical path formed in its outer periphery. The slide includes longitudinally spaced, shaped apertures. Preferably, the shaped apertures have long and short axes that are angularly displaced with respect to one another about the longitudinal axis of the slide. Coaction between one aperture and the outer surface of the diverging shank elements, as the other aperture follows the helical path and causes the slide to rotate, move the shank elements between their two positions. The cross-sectional configuration of the shank elements, the helical path and the shaped apertures can take on a variety of shapes. In one form, the helical path is formed by a twist in the shank elements and the elements diverge outwardly from the twist in a direction such that the elements remain in contact in the region of twist regardless of the position of the slide along the longitudinal length of the shank. In an alternate form, the helical path is formed in a separate guide member and the shank elements extend coaxially outwardly from the guide member. Preferably, a stop mechanism prevents the slide from sliding off of the blade end.
|
