Abstract: A retractable entry system is provided which is powered to extend and retract along a plurality of spaced-apart rotatable axes, in sequential, reciprocating arcs of motion. With the first axis and in the first of the sequences of motion when retracting, a portion of the step assembly folds onto another portion of the step assembly, the steps being aligned tread to tread. With the second axis and in the second of the sequences of motion in retraction, the folded step assembly rotates from a horizontal to a vertical orientation against and into the supporting vehicle. The completed sequences of motion allow the retracted entry systems to fit between the outer side wall of a vehicle and the vehicle chassis.

Abstract: An apparatus is provided which has sensors that detect pressure on opposite sides of a control valve which controls the flow of hydraulic fluid from a source to a hydraulic actuator. The sensors produce electrical signals indicating those pressures. In response to the sensor signals, a controller produces an output signal the operates a proportional control valve to thereby regulate pressure at a node of the hydraulic circuit. Several mechanisms are described that react to the pressure at the node by varying the pressure of the fluid being supplied to the main valve so that a controlled pressure level is achieved.