Control valve for vehicle air springs and the like

Claim 1

A pneumatic control valve for a vehicle suspension system for controlling the flow of compressible fluids to and from an air suspension spring comprising; a cylinder with a first, second and third ports therethrough spaced intervally along the cylinder wherein said ports enter the sidewall of said cylinder; said first port operably connected to a supply of compressible fluid; said second port operably connected to an air suspension spring; said third port being in fluid communication with the exteriof of said cylinder; a piston slidably mounted in the cylinder in abutting relationship with the interior of the cylinder; a piston rod rigidly connected to said piston and extending through the bottom end of said cylinder; said second port is at the top portion of the cylinder with the first and third ports positioned below said second port; said piston having a passage therethrough; said piston moveable to a first position such that said first port is in communication with said second port such that compressible fluid passes from said first port through said second port to said air spring and said piston seals the side of said cylinder sealing the third port from the said first and second ports; said piston moveable to a second position such that said piston seals the sides of said cylinder sealing all three ports from fluid communication with each other; said piston moveable to a third position such that said third port is in fluid communication with said second port such that compressible fluid passes from the air spring through the second port and through the third port and said piston seals the sides of the cylinder sealing said first port from the second and third ports; said passage through the piston fluidically connecting the second port with one of the first and third ports when said piston is in one of said respective first and third positions; the air spring being operably connected to the piston rod and cylinder such that the compressible fluids flowing in and out of said air spring control the position of said piston in said cylinder; the fluid which flows into the second port when the piston is in its first position moving the piston toward said second position and said fluid which flows out of the second port through the cylinder and through the third port when the piston is in its third position moving the piston towards said second position; the piston having sealing means mounted on the sidewalls thereof for sealing the ports when the piston is laterally aligned therewith; said passage through said piston having a first outlet at the top surface of said piston with said outlet in fluid communication with said second port and said second outlet aligned with one of the first and third ports when the piston is one of its first and third positions, respectively, such that said compressible fluid flows through the passage between said second port and one of the first and third ports, the other of the first and third ports being positioned above said piston and in fluid communication with the second port when the piston is in the other of its third and first positions respectively.