| 摘要 |
PCT No. PCT/EP87/00549 Sec. 371 Date Jul. 5, 1989 Sec. 102(e) Date Jul. 5, 1989 PCT Filed Sep. 28, 1987 PCT Pub. No. WO88/02453 PCT Pub. Date Apr. 7, 1988.A transmission ratio selector mechanism for a transmission having two ratio selector couplers both of which must be engaged to provide drive through the transmission. The selector mechanism includes a selector shaft which is rotatable about its longitudinal axis and also axially moveable parallel to its longitudinal axis. Rotation of the selector shaft is arranged to operate one of the couplers via a mechanical linkage including a twin-armed member and a pivoted lever while axial movement of the shaft operates the other coupler via a fluid pressure-operated actuator and an associated control valve mechanism. An interlock is provided to ensure that the fluid pressure-operated coupler is always engaged before the mechanically operated coupler. The interlock comprises a formation which is movable with the shaft and cooperates with a formation movable with the coupler which is to be engaged first. |
