Patent ID: 9657749
Date: 2017-05-23
CPC Classifications: B60G,F04B,F15B,F16K,Y10T

Claim:
1. A hydraulic suspension system comprising: a controller; a pump adapted to provide a source of pressurized fluid and a tank adapted to hold a reservoir of fluid, the tank in fluid communication with the pump; a suspension cylinder in selective fluid communication with the pump, the suspension cylinder defining a chamber therein adapted to receive pressurized fluid; a proportional pressure-reducing/-relief control valve interposed between the pump and the suspension cylinder and between the suspension cylinder and the tank, the control valve in electrical communication with the controller and in selective fluid communication with the pump, the tank, and the suspension cylinder, the control valve including a spool reciprocally movable over a range of travel between at least a pump flow position in which the pump and a control port of the control valve are in fluid communication with each other and a tank flow position in which the tank and the control port of the control valve are in fluid communication with each other, the control valve adapted such that the spool moves in response to a control signal received from the controller; a logic element interposed between the control valve and the suspension cylinder, the logic element in fluid communication with the control valve and in selective fluid communication with the suspension cylinder, the logic element including a poppet selectively movable between a through-flow position in which fluid can flow in either direction between the chamber of the suspension cylinder and the control port of the control valve and a blocked position in which fluid is prevented from flowing out of the chamber of the suspension cylinder, the poppet biased to the blocking position, the poppet adapted to move from the blocking position to the through-flow position when a pressure at a fluid region upstream of the poppet exceeds a predetermined crack pressure, the fluid region upstream of the logic element poppet being in fluid communication with the control port of the control valve.