| 摘要 |
The invention relates to an anti-roll back device (5) of particular applicability to motor vehicles but which can be applied to any rotating member where in ordinary useage the rotatable member is required to be rotated in one direction and prevented from rotating in the opposite direction but which has the further capability of being activated to permit the rotation in the opposite direction as and when it is required. This objective is met by a construction comprising engagement means for association with a rotatable member, said engagement means being a loop (13) or noose of a flexible material formed from or faced with a friction material, the loop or noose being adapted to pass around said rotatable member (7) from an anchor point (12) to a rotatable spindle (9) and to which the free end of the loop or noose is secured, said spindle being adapted for location in relation to said rotatable member such that rotation of said spindle in one direction puts said loop or noose in a first condition where the loop or noose is caused to slacken to allow free rotation of the rotatable member and rotation of said spindle in the opposite directon puts said loop or noose in a second condition, and in which second condition immediately the said rotatable member attempts to rotate in the opposite direction the said loop or noose can self tighten on said rotatable member to prevent that opposite rotation and there being means (22-32) selectively activatable to rotate said spindle in the required direction. |
