Pneumatic pressure responsive valve assembly

A pneumatic pressure responsive valve assembly comprising:

• a housing;
• diaphragm piston means including a diaphragm member and a piston member, said diaphragm member having an outer periphery secured to said housing and an inner periphery secured to said piston member;
• two pneumatic chambers defined by said diaphragm piston means within said housing, one of said chambers selectively receiving both fluid pressures which are higher and lower than those within the other of said chambers during operation of said valve assembly;
• said diaphragm member having a curvature which expands in a first direction towards one of said chambers;
• a rounded portion formed on said housing corresponding to a concave configuration of said curvature of said diaphragm member and spaced from said curvature of said diaphragm when said valve assembly is in an inoperative state to thereby prevent said curvature of said diaphragm member from turning over, said rounded portion being connected to said housing via an extension of said housing, said extension being curved toward said first direction and fixedly securing, in cooperation with an opposed portion of said housing, said outer periphery of said diaphragm member and orienting said outer periphery in said first direction;
• and
• a valve member for cooperation with movement of said piston member, wherein said piston member has an extension curved toward said first direction and fixedly securing, in cooperation with an opposed portion of said piston, said inner periphery of said diaphragm member and orienting said inner periphery in said first direction, and wherein the ends of said diaphragm are oriented in planes substantially perpendicular to a plane oriented in said first direction.