Suspension system for vehicles

Claim 2

A vehicle suspension system comprising a fluid reservoir, a fluid pump, a variable volume fluid suspension unit between sprung and unsprung portions of a vehicle, conduit means interconnecting said suspension unit, reservoir and pump, control means interposed in said conduit means and being operable in rEsponse to a first signal to increase pressure and to a second signal to decrease pressure in said suspension unit, means for operating said pump in response to said first and second signals, said control means being initially responsive to said first signal to communicate said reservoir with said suspension unit to equalize pressures in said suspension unit and said reservior when the pressure in the latter is higher than in said suspension unit and said pump being operable thereafter to receive air from said reservoir and deliver air to said suspension unit until said first signal is terminated, said control means being initially responsive to said second signal to communicate said suspension unit with said reservoir independently of said pump to equalize pressures in said suspension unit and reservoir when the pressure in said suspension unit is higher than the pressure in said reservoir and said pump being operable thereafter to receive air from said suspension unit and deliver it to said reservoir until said second signal is terminated.

Claim 3

The combination of claim 1 in which said control means includes a plurality of valves, each of said valves having an inlet and an outlet, said valve normally being closed and being responsive to a pressure at said inlet greater than at said outlet to open selected ones of said valves and being movable to an open position in response to one of said signals independantly of the pressure at said inlets and outlets.

Claim 4

The combination of claim 1 in which said control means include first, second, third, and fourth valve means, said valve means including an inlet and an outlet, said valve means normally being closed and being movable to an open position in response to a pressure at said inlet greater than at said outlet, said pump having an air intake means and an air discharge means connected to outlets of said first and fourth valve means, and suspension unit being in communication with the inlet of said first valve means and with the outlet of said third valve means and said reservoir being in communication with the inlet of said fourth valve means and with the outlet of said second valve means.

Claim 5

The combination of claim 3 in which said first and second valve means are responsive to said first signal to move to an open position and in which said third and fourth valve means are responsive to said second signal to move to an open position.

Claim 6

The combination of claim 4 in which said valve means include solenoid means for moving said valve means from a closed to an open position.

Claim 7

The combination of claim 1 and further comprising electrical means for driving said pump in response to said signals.

Claim 8

An air suspension system for a vehicle including a pump having an intake port for receiving air and a discharge port for delivering air, a reservoir, and a variable volume suspension unit adapted to be disposed between sprung and unsprung portions of a vehicle, in combination; first valve means controlling communication between said discharge port and said suspension unit and between said intake port and said reservoir and normally being closed, second valve emans controlling communication between said discharge port and said reservoir and between said intake port and said suspension unit normally being closed, actuating means responsive to a first signal of a change of spacing between said sprung and unsprung portions to open said first valve means to increase pressure in said suspension means and responsive to a second signal to open said second valve means to decrease pressure in said suspension means, said first valve means being responsive to a pressure in said suspension unit greater than in said reservoir to open said first valve means when said second valve means are open to communicate said suspension unit to said reservoir independently of said intake and discharge ports to equalize pressures in said reservoir and suspension units, and said second valve means being responsive to a pressure in said suspensiOn units less than in said reservoir to open said second valve means when said first valve means are open to equalize pressures in said reservoir and said suspension means.

Claim 9

An air suspension system for a vehicle including a pump having an intake port for receiving air and a discharge port for delivering air, a reservoir, and a variable volume suspension unit adapted to be disposed between sprung and unsprung portions of a vehicle, in combination; first valve means controlling communication between said discharge port and said suspension unit and between said intake port and said reservoir and normally being closed, second valve emans controlling communication between said discharge port and said reservoir and between said intake port and said suspension unit normally being closed, actuating means responsive to a first signal of a change of spacing between said sprung and unsprung portions to open said first valve means to increase pressure in said suspension means and responsive to a second signal to open said second valve means to decrease pressure in said suspension means, said first valve means being responsive to a pressure in said suspension unit greater than in said reservoir to open said first valve means when said second valve means are open to communicate said suspension unit to said reservoir independently of said intake and discharge ports to equalize pressures in said reservoir and suspension units, and said second valve means being responsive to a pressure in said suspensiOn units less than in said reservoir to open said second valve means when said first valve means are open to equalize pressures in said reservoir and said suspension means.

Claim 10

The combination of claim 7 including driving means for operating said pump, said driving means being operable in response to said first and second signals.

Claim 11

The combination of claim 7 in which said first valve means includes a pair of valves, one of said valves controlling communication between said discharge port and said suspension unit, the other of said valves controlling communication between said intake port and said reservoir and which said second valve means includes a pair of valves, one said valve controlling communication between said discharge port and said reservoir and the other of said valves controlling communication between said intake port and said suspension unit.

Claim 12

The combination of claim 9 in which said pairs of valves of said first and second valve means each have an inlet and an outlet and in which said valves are responsive to a pressure greater at said inlet than at said outlet to move to an open position.

Claim 13

The combination of claim 10 in which said one of said pair of valves of said first and second valve means have their said outlets in constant communication with each other and their said inlets connected to said air suspension unit and said reservoir, respectively, for equalization of pressure in said suspension unit and said reservoir when said other valve of said pair of valves of said first and second valve means is in an open position in response to said first or second signals.