| 摘要 |
A reversible gearless drive mechanism for a socket wrench comprises a driven member having an upper centering support flange and a lower centering support race, between which is a cam-like area around the circumference defining three symmetrically opposite bi-directional ramps. The driven member is axially centered within a drive member defining a round cylindrical bore, between which each bidirectional ramp forms one right hand wedge and one left hand wedge. Between each two bi-directional ramps are two cylindrical rollers held apart into their respective left hand and right hand wedges by a leaf spring. The cammed circumference of the driven member does not contact the inner circumference of the bore for centering support permitting the use of larger diameter rollers relative to the diameter of the bore in which the mechanism is centered. The larger diameter rollers combined with the pressure of the leaf springs provide adequate friction drag to hold the driven member stationary while a thumb operated rotary selector switch overcomes a spring and pin detente to unwedge either the three left hand or the three right hand rollers to change the direction of drive. This permits a change in drive directions with only one available hand. The larger diameter rollers also provide a more positive lock for the drive and are more tolerant to small particles and imperfections caused from wear or contamination.
|
