BigPatents India

A transmission selector mechanism for controlling a gearbox which provides forward/reverse direction and high/low ratios using two coupling members (6â™, 53:7â™, 54) each axially slideable in both directions either side of the a respective neutral position to couple a selected one of a pair of gears (10, 12:11, 13) to an associated shaft (4, 5). The mechanism includes a driver operated forward/reverse selector member (50) and a driver operated high/low ratio selector member (52). The forward/reverse selector member (50) moves a first selector formation (64, 64b) which is engageable with a first coupling formation means (66) on a first cam (61) which moves one of the coupling members (7â™, 54). The high/low selector member (52) moving a second selector formation (63, 63b, 63c) which is engageable with a second coupling formation means (65) on a second cam (58) which moves the other coupling member (6â™, 53). One of the selector formations (63, 63b, 63c) engages both coupling formation means (65, 66) for simultaneous movement of both couplers (6â™, 7â™) when selecting certain direction/ratio changes.