Loader

In a loader including a frame supported on front and rear axles carrying front and rear sets of wheels, a hydraulically operated extension arm mounted to the frame for swinging vertically between lowered and raised positions, an extensible and retractable hydraulic cylinder coupled between said frame and said extension arm for selectively moving said arm between said lowered and raised positions, a first supply line coupled to a piston rod side of said hydraulic cylinder, a second supply line coupled to a piston side of said hydraulic cylinder, a pressurized hydraulic fluid source, a hydraulic fluid tank, at least one mechanically switchable control device coupled, on the one hand, to said first and second supply lines and coupled, on the other hand, to said fluid source and fluid tank and being selectively operable for controlling the flow of hydraulic fluid to and from said hydraulic cylinder, a load sensor located on said loader for monitoring a load condition on the loader and operable for creating an electrical load signal representing said load condition, and an electronic control unit coupled to said load sensor for receiving said electrical signal and comparing it with a critical load stored in memory in said electronic control unit and for generating a control signal representing a difference between said load signal and said critical load, the improvement comprising:

• an electrically operable variable restriction device being coupled between said first and second supply lines and including an electrical controller connected for receiving said control signal from said electronic control unit and being operable in response to said control signal for establishing a restricted flow path between said first and second supply lines when said sensed load approaches a value equal to said critical load.