Plastic valve core

Claim 1

A valve core adapted for incorporation within a valve stem or body having interior threads, said valve core comprising a unitary molded plastic cylindrical barrel having an axial bore extending therethrough, and an external threaded portion thereon, at a first or outer part of said barrel, adapted for threaded engagement with the interior threads of said valve body, said threaded portion including an oblong bridge adapted for ready engagement by a tool, the first end of said barrel at said bridge having an opening from said bore; means for providing that the second or inner part of said barrel is adapted by itself to effect the required static seal with respect to said valve body, said means including an inwardly tapered internal portion of said valve body; a broad planar annular surface area of contact defined between the inner and outer peripheries at the second or inner end of said barrel; a unitary elongated cylindrical valve pin with enlarged inner and outer ends, the inner end being cylindrical, said pin being disposed within said barrel in an axial relationship therewith, and said pin being slidably received within said bore; said valve pin having adjacent its second or inner end a conical portion whose greatest diameter is substantially equal to the bore diameter, and having a cylindrical portion immediately below the conical portion, the cylindrical portion having a diameter substantially equal to said greatest diameter; a cylindrical sealing washer surrounding said lower cylindrical portion of said valve pin and having a corresponding broad planar upper surface for contacting said broad planar annular surface area of contact defined at the inner end of said barrel, the outer diameter of said sealing washer being substantially equal to the diameter at the outer periphery of the inner end of said barrel, the lower surface of said sealing washer being adapted to engage the integral, cylindrical, enlarged inner end of said pin, said end having a fixed diameter substantially equal to the outer diameter of said washer, whereby said washer is compressible against said broad planar annular contact area in sealing relationship therewith by movement of said pin axially outwardly.