Abstract: A hydraulic steering system for turning two mutually articulated vehicle-halves (13, 14) relative to one another with the aid of two hydraulic piston-cylinder devices (11, 12) includes a control valve (17) which will normally connect the piston-cylinder devices in a manner such that the devices operate as single-acting piston-cylinder devices. When abnormally high steering torque prevails, however, and the oil pressure rises correspondingly above a pre-determined value, the setting of the control valve is adjusted by these oil pressures so that the valve connects the piston-cylinder devices in a manner which causes the devices to operate as double-acting piston-cylinder devices.

Abstract: A loading machine equipped with a first and a second pump for supplying hydraulic oil to at least one hydraulic operated working component, such as a hydraulic piston-cylinder device or a hydraulic motor having a varying oil-pressure and flow requirement, wherein the pumps can be connected together for mutual coaction, when necessary. The second, larger pump is a fixed displacement pump. The first pump is provided with a pump regulator which is influenced by the load pressure prevailing in the hydraulic system and is intended to influence the first pump in a manner to maintain between the outlet of the pump and the load pressure on the pump regulator a pressure difference determined by the pump regulator, wherein the first pump is connected to the working component via a variable restriction. A control device is operative to connect the second and larger pump to the system solely when there is a need for a smooth increase in flow which cannot be achieved solely by the first pump.

Abstract: A linkage system for loading machines is mounted on two lift-arms (14) supporting a pallet-lifting fork or a bucket (22) at the ends of the lift-arms. The linkage system is so designed that when using a bucket (22) or pallet-lifting fork the linkage system will ensure that the bucket or lifting fork will take a substantially desired angular position as it is raised and lowered, without needing to make adjustments to the tilt-cylinder as the bucket or lifting fork is raised.