US Patent 6928894 Compensated actuator with optimized power

An actuator combining mechanical and hydraulic forces includes a cylindrical body and a piston that can slide relative to the cylindrical body. The piston and the cylindrical body are connected by a mechanical system for transmitting mechanical power that constitutes a device that permanently controls the position of the actuator, a permanent locking device, and a safety device. The device for transmitting hydraulic power constitutes a load compensator device. The two power transmitting devices operate in parallel. Position control using the drive system at reduced power can be synchronized in a simple way for a plurality of actuators.