A drive controller for a hydraulic drive system, a three wheeled vehicle having a pair of transversely arranged in line of drive shaft assemblies and a single wheel drive shaft assembly each assembly including a drive unit having two separate drives and has for series operation secondary hydraulic feed lines between one of the drives of the single drive units and one of the drives of each transverse drive unit. A pressure release valve is provided in each secondary line which valve is fed through a non-return valve.

A drive system for a hydraulically driven vehicle which includes bidirectional hydraulic motors. Two front hydraulic motors are in parallel as are two rear hydraulic motors. One of the front hydraulic motors is in series with the rear hydraulic motor on the same side of the vehicle. The other front hydraulic motors is in series with the rear hydraulic motor in the other side of the vehicle. The rear hydraulic motors include mechanical brakes in combination. The front hydraulic motors are mounted as part of the spindles which pivot about king pins.

There is provided a traveling drive apparatus in a working vehicle having a traveling body with front wheels and rear wheels which are adapted to be controlledly driven respectively, characterized in that: the traveling body has mounted thereon an engine, a transmission and a hydraulic pump which are coupled to the engine and a first hydraulic motor that is adapted to be driven by the hydraulic pump whereas a left hand side wheel and a right hand side wheel on one of a front side and a rear side of the traveling body are adapted to be selectively coupled to either of an output side of the engine and an output side of the first hydraulic motor; and a left hand side wheel and a right hand side wheel of the other of the front side and the rear side are mounted on a suspension unit having a second hydraulic motor and a third hydraulic motor which are provided independently of each other and are adapted to be driven by the hydraulic pump and which are respectively coupled to the left hand side wheel and the right hand wheel of the other of the front side and the rear side of the traveling body.

An articulated loader has an articulated chassis and two A-frames. The points of the A-frames face each other. The articulated chassis includes a front portion and a rear portion. Likewise, there is a front or first A-frame and a rear or second A-frame. The A-frames are connected to the overall chassis at points close to but offset from the point of vehicle articulation via ball joints and via hydraulic suspension cylinders toward the wider portions of the "A"s. The vehicle is propelled along the ground by independently driven tracks. The invention includes a feature to limit the motion of the suspension system based on the load applied to the suspension cylinders, i.e., the pressure experienced by the head end of the suspension cylinders. This is accomplished via pilot operated check valves.

An articulated loader has an articulated chassis and two A-frames. The points of the A-frames face each other. The articulated chassis includes a front portion and a rear portion. Likewise, there is a front or first A-frame and a rear or second A-frame. The A-frames are connected to the overall chassis at points close to but offset from the point of vehicle articulation via ball joints and via hydraulic suspension cylinders toward the wider portions of the "A"s. The vehicle is propelled along the ground by tracks that are independently suspended. The A-frames are of approximate equal length along the axis of the vehicle and the ball joints are located as close as practical to the articulation joint. Thus, any vertical forces at the ball joints due to variations in tractive efforts for the vehicle tend to be equal and opposite in direction and to, therefore, minimize any chassis height variations.