Abstract: A transmission for a tractor in which a main shaft to receive engine power, a travelling speed change shaft and a PTO speed change shaft are disposed in parallel with one another. A first travelling speed change means of a hydraulic clutch type is disposed on the travelling speed change shaft and provided with clutch means for backward travelling and first-stage forward travelling. A second travelling speed change means of a hydraulic clutch type is connected to and disposed rearwardly of the main shaft and provided with clutch means for second-stage, third-stage and fourth-stage forward travelling. The second hydraulic clutch type travelling speed change means is so constructed that, in response to power input from the main shaft, the clutch function thereof is performed prior to the speed change function thereof.

Abstract: A gear transmission comprising a driving transmission shaft, a driven transmission shaft, a gear shaft between the two transmission shafts, three speed change gears of different diameters mounted on the gear shaft, an auxiliary speed change shaft carrying three gears of different diameters respectively in mesh with the speed change gears, and two clutch members provided between one or the other of the transmission shafts and the gear shaft. Each clutch member provides two speeds by switching between a position to connect one of the transmission shafts to the gear shaft and a position to connect the transmission shaft to one of the speed change gears. Thus the gear transmission provides a total of four speeds.

Abstract: A transmission mechanism for vehicles comprising main clutch means having a primary clutch and a secondary clutch, primary and secondary propeller shafts for primary and secondary transmissions adapted to be intermittently rotated by the operation of said main clutch means, a first transmission system adapted to transmit the transmission power of said primary propeller shaft, a second transmission system adapted to transmit the transmission power of said secondary propeller shaft, and a reduction gearing for interlocking said secondary propeller shaft with said second transmission system. Further disposed is a transmission unit having a uni-directional clutch adapted to permit engine power to be transmitted only in the direction from said secondary propeller shaft to said primary propeller shaft.

Abstract: Hydraulic control system including a bypass provided in an intermediate portion of an oil passage extending from a position control valve to a hydraulic actuator for raising and lowering a working implement. A draft control valve disposed in the bypass controls the pressure of oil flowing into the bypass, in response to the displacement of a member for sensing the draft force of the working implement.