Valves for vehicle heating systems

Claim 1

A plastic valve for a motor vehicle heater system, comprising a housing, inlet and outlet ports formed coaxially in said housing, and a substantially planar closure member mounted in said housing for pivotal movement between an open position and a closed position about an axis parallel to said axis of said ports, said closure member being substantially quadrantal and extending in a plane perpendicular to said axis of said ports and having an aperture which communicates between said inlet and said outlet ports when the closure member is in said open position, said closure member having a predetermined substantially rigid thickness through a substantial portion of its area including that portion carrying said axis and forming said aperture and a thinner more flexible portion which covers said outlet port when the closure member is in said closed position, said flexible portion of said closure member being stiffened locally in the area of said thin flexible portion which covers said outlet port when said closure member is in the closed position with said flexible portion permitting flexing movement of the closure along the axis of said ports to insure sealing at low pressures between said ports and said closure member further having notches in its periphery, said notches traversing said outlet port as said closure member pivots from said open position to said closed position, with said notches acting as pressure relief means between said open and closed positions.