| 摘要 |
<p>A vehicle such as a tractor has a main change-speed gear with an associated clutch and also has a gear, represented by its selector rod (34), which can be shifted under load between a normal position and an under-speed position which produces increased tractive effort by reducing the speed by about 20%. This load change gear can be operated by the same lever as operates the main change speed gear. In order to prevent simultaneous operation of the main gear and the load change gear, with corresponding interference with the synchronisation of the main gear, an interlock device 26 is provided. A bellows (44) is connected into the hydraulic circuit for the clutch and, when the clutch pedal is depressed, the bellows (44) holds a plunger (48) in locking engagement with one of two grooves (38, 40) in the selector rod (34). In other embodiments a mechanical linkage between the clutch pedal and the interlock device is provided.</p> |
