US Patent 7117670 Control device

A control device, in particular for working machines, such as wheel loaders, excavators or similar devices, includes at least one working tool (12), particularly a working shovel that can be actuated by at least one hydraulic working cylinder (10). The device has a control block for controlling the hydraulic fluid paths between the working cylinder (10), a hydraulic fluid supply (P) and a tank (T). The device also has at least one hydraulic accumulator (22) and a shut-off or stop valve (32). The shut-off valve has a controllable valve member (34) and is located between the working cylinder (10) and the accumulator (22). The valve member is connected in the transmission position for connecting the accumulator (22) in order to damp the motion of the working cylinder (10). A selector valve (26) that can be controlled by the control block (20) is connected in the feed line (24), blocking the line (24) in the non-actuated state. The shut-off valve (32) is connected in a secondary line (30) that is connected to the feed line (24), The shut-off valve is impinged in the open direction by accumulator pressure, and is decompressed in the closed direction. This permits increased safety to be achieved for working machines, and prevents an excess load from being placed on the damping accumulator.