| 摘要 |
The selector rings of a countershaft gearbox are moved axially of the mainshaft to engage and disengage the gears 1, 2 by respective pairs of push-rods 15 and 16 which extend inwardly between the gears. The push-rods 15 and 16 bear on oppositely-inclined faces 22 of pairs of blocks 17 which slide in slots 18 parallel to the mainshaft and which engage respective selector rings at diametrically opposite locations. Actuation of one pair of rods 15 or 16 causes their blocks 17 and the engaged ring to move in one direction whereas actuation of the other pair causes movement in the opposite direction. The rods 15 and 16 slide within mounting blocks 19 inset between pairs of the gears 1-6, and are actuated by the cam surface of a longitudinally-driven rack 25. Alternatively, the push-rods 47 and 48 (Fig 8) are actuated by individual hydraulic rams 45,46. |
