Patent ID: 6053192
Filing Date: 2000-04-25
Classification: G05D,Y10T

Abstract:
An apparatus for regulating an output pressure of an operating fluid, comprising:a housing having a chamber and a pressure output port in fluid communication with an output portion of said chamber;a piston having an interior cavity and a first flow port which is in fluid communication with said interior cavity and an exterior of said piston, said piston having at least a portion thereof disposed within said chamber in moveable relation with said housing with said first flow port of said piston being disposed in fluid communication with said chamber;a first seal which extends between said piston and said chamber of said housing, on an opposite side of said first flow port through said piston from said output portion of said chamber;a biasing member extending between said piston and said housing such that a biasing force is exerted against said piston which increases as said piston is moved in a first direction and decreases as said piston is moved in a second direction;an operating member disposed within said interior cavity of said piston, said operating member having a second flow port which is disposed at a selected distance from a first end of said housing and which is in fluid communication with a supply operating fluid pressure;a second seal which is disposed between said operating member and said interior cavity of said piston, said second seal being moveable relative to one of said first and second flow ports to prevent flow of the operating fluid from said second flow port to said first flow port;a third seal which is disposed between said operating member and said interior cavity of said piston, for sealing said interior cavity of said piston on an opposite side of at least one of said first and second flow ports from said second seal;wherein said piston moves within said chamber of said housing to position said second seal relative to said first and second flow ports to pass the operating fluid between said first and second flow ports in response to said output pressure falling beneath a selected value, and said piston moves within said chamber of said housing to position said second seal relative to said first and second flow ports such that the flow of the operating fluid between said first and second flow ports is restricted in response to said output pressure exceeding said selected value; anda vent passage extending from said interior cavity of said piston, through one of said operating member and said piston, and across oppositely disposed sides of said second and third seals to vent said interior cavity of said piston across at least a portion of said operating member about which said second and third seals are disposed to equalize pressure therebetween.