Abstract: Disk brake apparatus mounted on a differential gear shaft extending from each side wall of a transmission case. A cam plate and balls coact to press a brake disk mounted on the differential gear shaft against a friction surface. Each of the balls is in direct or indirect point-to-point contact with the outer side wall of the transmission case to reduce the sliding resistance involved.

Abstract: Construction for uniting by welding a brake case cover, a rear wheel axle case and a terminal speed reduction unit case which are all made of sheet metal. The rear wheel axle case has at its opposite ends precisely circular tubular portions fitting in the brake case cover and in the terminal speed reduction unit case to connect them together. The united parts are joined together by automatic welding. The rear wheel axle case has a flat tubular intermediate portion for mounting a fender or the like thereon. The flat tubular portion has a smaller sectional area than the opposite end tubular portions so as to be substantially flexible and to thereby absorb concentric loads on the weld joints.

Abstract: Front wheel drive assembly comprising a tubular front wheel axle housing and rotatably supporting a differential yoke shaft having a bevel pinion at its outer end, a gear case fixedly mounted on the outer end of the front wheel axle and having a pin portion projecting from a cap of the case, an upright bevel pinion shaft housed in and rotatably supported by the gear case and having a bevel pinion meshing with the bevel pinion, the bevel pinion shaft having another bevel gear below the bevel pinion thereon, a front wheel hub shaft fixed to the disk of the front wheel and having a terminal reduction bevel gear, and a case housing the bevel gear on the hub shaft and rotatably supporting the hub shaft substantially coaxially with the yoke shaft, the bevel gear on the hub shaft meshing at its lower portion with the bevel gear on the bevel pinion shaft.

Abstract: Hydraulic double clutch comprising a tractor-driving clutch unit and a power takeoff clutch unit accommodated in a clutch housing serving also as an oil tank. Hydraulic pumps disposed in the housing have gears respectively meshing with a gear on the drive disk assembly of the double clutch to force the working oil into the clutch units through individual oil passages and to push the pistons of the units. Each of the oil passages is provided with a poppet valve at an intermediate portion thereof. The poppet valves are opened or closed to disengage or engage the clutch units independently of each other for interruption or transmission of the torque of engine. Each of the valves is automatically opened when the pressure on the piston builds up to excess and is therefore serviceable also as a pressure control valve. The valve is operable to bring the clutch unit into substantially semi-engaged state.