Patent ID: 7478489

Claim:
A control system for a loader on a construction apparatus including a frame and a hydraulic pump, the loader including a boom, a bucket, and a hydraulic cylinder including at least three chambers, the cylinder operably coupled between the boom and the frame, the control system including: a variable input configured to accept an operator instruction to float the bucket, the variable input configured to output a signal corresponding to the operator instruction; a control valve; an accumulator adapted to receive and store pressurized hydraulic fluid from at least one of three chambers of the hydraulic cylinder when the boom is lowered and supply pressurized hydraulic fluid to at least one of the three chambers of the hydraulic cylinder when the bucket is raised; a plurality of pressure sensors adapted to measure a hydraulic pressure in each of the three chambers of the hydraulic cylinder and output a plurality of corresponding signals; and a controller configured to receive the signal from the variable input and control the control valve and the hydraulic pump to float the bucket based on the signal from the variable input, the controller further configured to determine a first force applied to one of the chambers of the cylinder by the accumulator and control the pump and the plurality of control valves to supply pressurized hydraulic fluid to another chamber of the cylinder to overcome the first force when the float instruction is received by the variable input.