Draincock for automotive cooling system

Claim 1

A valve assembly for draining a fluid carrying vessel such as in an automotive cooling system, comprising a tubular integral body having external threads on a forward end, said body having a through bore, said through bore having internal threads at said rearward body end and a counterbore at said forward body end, said body including a radial end face at said forward end, a junction of said radial end face and said counterbore forming an annular valve seat, a valve stem having external threads in engagement with said internal body threads, said stem having an integral handle at a rearward end and an integral head at a forward end, said handle having a transverse width substantially greater than the diameter of said internal body threads, said stem having an axial passage extending from a point adjacent said head through a rearward face of said handle, said stem having a port on its periphery communicating with said axial passage to conduct fluid from a zone surrounding said head through said stem, said stem head having a conical tubular wall section along substantially its full length and increasing in diameter in a direction away from said handle, said conical tubular head being plastically deformed radially outwardly from an initial major diameter at least as small as said internal body threads to a major diameter sufficient to provide a conical sealing surface adapted to sealingly engage said seat.