| 摘要 |
PURPOSE:To improve operability by changing from a four-wheel mechanism to a two-wheel mechanism in case of running on road by connecting a pair of right and left braking pedals by connecting means, and changing from the two-wheel mechanism to the four-wheel mechanism by releasing the connection in case of plowed field word, and operating a front wheel speed increasing mechanism by operating one side braking pedal more than a fixed time. CONSTITUTION:A two-wheel drive mechanism 2 for transmitting power transmitted from a prime mover to right and left rear wheels 1 is disposed in the rear portion of a tractor, and a four-wheel drive mechanism 4 to which power is transmitted from the two-wheel drive mechanism 2 through a changeover mechanism 5 is disposed in the front portion thereof. A front wheel speed increasing mechanism 6 for increasing the peripheral speed of front wheels 3 more than the peripheral speed of rear wheels 1 and a speed increasing changeover mechanism 7 for switching transmission of the mechanism 6 are disposed in the front portion of the four-wheel drive mechanism 4. When a sensor 10 detects connection by connecting means 9 of both braking pedals 8, 8, the change-over mechanism 5 is switched to the two-wheel drive mechanism 2 side, and when it detects that connecting of the connecting means 9 is released, it is changed over to the four-wheel drive mechanism 4. When one side pedal 8 is operated more than a fixed time, the speed increasing changeover mechanism 7 is changed over to transmission by the front wheel speed increasing mechanism 6 according to output of a speed increasing sensor 11. |
