Patent ID: 7594451

Claim:
A transmission selector mechanism for controlling a gearbox which provides forward and reverse direction and high and low ratios using two coupling members ( 6 ′, 53 , 7 ′, 54 ) each axially slideable into position on either side of 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 comprising: a driver operated forward and reverse selector member ( 50 ) and a driver operated high and low ratio selector member ( 52 ), wherein the forward and reverse selector member ( 50 ) moves a first selector formation ( 64 , 64 b ) which is engageable with a first coupling formation means ( 66 ) on a first cam ( 60 ) which moves one ( 7 ′, 54 ) of the coupling members, wherein the high and low selector member ( 52 ) moves a second selector formation ( 63 , 63 b , 63 c ) which is engageable with a second coupling formation means ( 65 ) on a second cam ( 58 ) which moves the other coupling member ( 6 ′, 53 ), wherein one of the selector formations ( 63 , 63 b , 63 c ) engages both coupling formation means ( 66 , 65 ) for simultaneous movement of both couplers ( 6 ′, 53 : 7 ′, 54 ) when selecting both direction and ratio changes with one of the selector members ( 50 , 52 ); and wherein upon movement of one of the selector members ( 50 , 52 ), the coupling members ( 6 ′, 53 : 7 ′, 54 ) can be positioned in positions either on the same side or on opposite sides of their respective neutral positions.