| 摘要 |
The barrel (B) type cam in the gearbox has two guide paths (1a,1b) on its periphery. Each guide path has two chicanes (9a,11a,9b) so that as the barrel rotates the cam followers (3a,3b) move forks (5a,5b) to operate the gear change. Either of these cam followers (3a,3b) can be disengaged by the axial operation of a rod, in a disengaging assembly (A) so that the respective operating fork is maintained in a neutral position. The guide paths (1a,1b) on the periphery of the barrel (B) have chicanes (9a,11a,9b), which guide the cam followers (3a,3b) coupled to the forks (5a,5b) in an axial direction. The disengaging assembly placed between the barrel (B) and the forks (5a,5b) consists of modules housing spring loaded cam followers and a axial moving rod (17) containing recesses along its length. When these recesses come in line with the rear of the cam followers, the spring partially retracts the followers (3a,3b) out of the guide paths. Thus at the chicanes, where the grooves are stepped (13a,15a,13b), the cam follower has no axial movement but stays in a neutral position. |
