Patent ID: 7559733

Claim:
A refuse vehicle including a lifting arm mounted to the vehicle, said arm having a container holding and lifting apparatus, a refuse storage body including a packer that pushes refuse towards a rear door, said rear door upon being opened, and the body tilted, allows compacted refuse to be discharged, a hoist for tilting said body, a positive displacement pump with an associated valve system in fluid communication with a drive mechanism that operates the packer, the rear door, the hoist, and the lifting arm, said valve system including a plurality of closed-centered valves each with a spool mechanism having a pressure compensator to maintain a constant flow rate of fluid through each valve regardless of differential in pressure across each valve for any given position of the spool mechanism, and an electrical/electronic control system that controls the speed and direction of movement of the spool mechanisms, the highest load pressure amongst the valves being sensed to adjust an associated pump pressure compensator to that pressure plus a predetermined additional pressure, pressure compensated flow control through each said valve being maintained at a constant flow of hydraulic fluid proportional to spool mechanism position of a respective said valve regardless of pressures.