| 摘要 |
PURPOSE:To increase safety in driving by shifting a shift position to one-step lower side by a control unit when right and left brake pedals are detected to be disconnected, in a traveling vehicle such as tractors, etc. where right and left brake pedals are free to be connected. CONSTITUTION:In the electronic speed changing unit of a tractor, a speed changing button provided on a control unit 5 is pressed to operate a shifter 8 by a specified hydraulic cylinder 7 according to an operating instruction from the control unit 6a of a CPU6 in a control box, thus shifting main and auxiliary transmission 3 and 4 into their desired shift positions. In this case, a brake connection sensor 17 for detecting the connected condition of right and left brake pedals 16, 16 is provided and its output signal is input into the CPU6 together with output signals from a vehicle speed setting unit 18 and a stroke sensor 19. When the right and left brake pedals 16, 16 are in disconnected condition shifting instruction to shift to one-step lower side is produced where the vehicle speed coincides with the set value. |
