| 摘要 |
PURPOSE:To prevent slippage of a frictional power transmitting section of a transmission and to improve controllability of the transmission, by providing an automatic control mechanism for shifting the transmission to a speed reducing position automatically when occurrence of slippage at the frictional power transmitting section of the transmission is detected along with increasing of load, and enabling to make the automatic control mechanism operative or inoperative selectively according to the circumstances. CONSTITUTION:The speed of rotation of an engine output shaft 27 is kept within a prescribed limited range by affording output signals of a first detecting means 21 for detecting the operational conditions of a transmission, a second detecting means 22 for detecting the speed of rotation of an output shaft 12 of the transmission 7, and a third detecting means 23 for detecting the speed of rotation of the output shaft 27 of an engine E to an automatic control mechanism 29. In this state, if the speed of rotation of the output shaft 12 of the transmission 7 becomes lower than a specific range of speed preset in the first detecting means 21, transmission 7 is shifted to a speed reducing position automatically and in a reversible manner by the automatic control mechanism 29. Further, there is provided a switch S which is assembled in a handle 31 of a manually operated means 31 to be capable of switching the mechanism 29 into inoperative state simply by grasping the handle 31. |
