Patent attributes
A hydraulic force control system is disclosed for controlling the clamping force applied to a load by the clamp arms of a clamping attachment of a load-lifting vehicle to prevent the arms from over- or under-clamping the load. The system includes a force control circuit interposed between the vehicle's conventional hydraulic circuit and clamp cylinders of the attachment that operate the arms. When a manual control valve in the conventional circuit is moved to operate the clamp arms, a load sense cylinder in the control circuit lifts a load carriage of the attachment, causing the pressure side of the sense cylinder to sense the weight on the load carriage. Carriage movement actuates a sequence valve in the control circuit to hydraulically connect the pressure sides of said sense and clamp cylinders so that clamping force applied to a load by the clamp arms is proportionate to the weight of the load.
