Patent ID: 9050947
Filing Date: 2015-06-09
Classification: B60S

Abstract:
1. A hydraulic leveling system for a vehicle, comprising: at least one set of double acting hydraulic jacks, each jack having an extend side to which hydraulic fluid under pressure is admitted to extend the jack and from which hydraulic fluid exits to retract the cylinder and a retract side to which hydraulic fluid under pressure is admitted to retract the jack and from which hydraulic fluid exits to extend the cylinder; hydraulic fluid; a pump that pressurizes the hydraulic fluid; a reservoir from which the pump draws hydraulic fluid and to which hydraulic fluid is returned; valves in communication with the jacks, pump and reservoir that are selectively actuable to extend one or more of the jacks by applying hydraulic pump pressure to the extend side and relieve hydraulic pressure from the retract side of the one or more of the jacks and to retract one or more of the jacks by applying hydraulic pump pressure to the retract side and relieve hydraulic pressure from the extend side of the one or more of the jacks; a pressure sensor with a pressure set point that is actuated when the pressure set point is exceeded, in response to which the system generates a signal indicating retraction of the jacks; and a controller connected to the pump, valves and pressure sensor that operates so that after the pressure sensor set point is exceeded, the system turns off the pump and continues to hold open one or more of the valves to apply pressure from the pump to the retract side of the jacks and permit flow from the extend side of the jacks to be relieved for a delay period of time after which the controller checks whether the pressure sensor is still activated and if it is not still activated, turns the pump back on and continues to retract the jacks.