| 摘要 |
An anti-roll back device for vehicles is of the general type where a loop or noose is caused to tighten on a drive shaft or a brakedrum on the drive shaft when the drive shaft attempts to make unwanted reverse rotation. To improve on this construction, we propose a construction where the loop or noose extends around a cranked member pivotally mounted in closely spaced relationship to the drive shaft or brake drum, and an arrangement to pivot the cranked member between a first position where the loop or noose can engage the drive shaft or brake drum and prevent the opposite rotation, and a second position to render the loop or noose inoperative during any period where the drive shaft or brake drum is positively required to be rotated in the reverse direction and there being further structure to hold the crank in its second position until the drive shaft or brake drum has ceased rotating in the reverse direction. |
