Proportional Control of Vehicle-Mounted Lifting Arms Using Electronic Servomechanism-Operated Hydraulic Valves

A controller for electronically controlling hydraulically operated lifting arms. The controller allows a wide range of quicker movement and slower movement of the lifting arms under proportional control by the operator. An electronic servomechanism is mechanically coupled to a hydraulic valve handle to control the operation of the lifting arms. The servomechanism turns a shaft in response to a proportional controller. The valve handle controls the hydraulic valve stem, allowing the hydraulically operated lifting arms to raise, lower, grip, release, and perform auxiliary hydraulic operations.