Abstract: A hydraulic installation with means for storing energy produced by the prime mover during a rest period of the installation. Energy is stored by a fluid accumulator by suitable positioning of control valves during the reset period. Control of the valves is effected by a logic circuit responsive to pressure in the accumulator, pressure in the main feed conduit leading to the driven device, and the position of a feed conduit control valve.

Abstract: In a method of subordinating the orientation of a grab on a Public Works machine to the angle of rotation of the turret three directions are chosen, the first two being determined by the desired orientation of the grab in the loading and unloading zones, respectively, and the third passing through the axis of rotation of the turret 2, the angle of rotation of the turret starting from the third direction is measured and compared with the angle between a straight line, passing through the point of intersection of the first two directions and the axis of rotation of the turret, makes and the third direction, the desired angle of the grab with respect to the boom in the loading or unloading zones is determined and the angle that the grab actually makes with the boom is measured and compared with the appropriate desired angle, the results of this comparison being used to control rotation of the grab to reduce the difference to zero.