Appeal No. 2003-1332 Page 5
Application No. 09/797,143
27) having a valve head (valve face 273) shaped to be received by the valve seat in
sealing relation wherein the poppet is movable relative to the nozzle portion between a
closed position in which the fluid conduit is blocked and an open position in which the
fluid conduit is at least partially unblocked.
Danis' invention relates to an improved method of making an engine valve and
more particularly to an improved process for forming poppet-type valves of the type
used in internal combustion engines employing a ductile low-carbon steel which
facilitates the formation by cold forging and/or extrusion relatively intricate valve
configurations followed by a subsequent preliminary machining and case hardening
treatment and thereafter a final machining operation resulting in a valve having
excellent performance characteristics and which is substantially simpler and more
economical to manufacture. Danis teaches (column 1, lines 20-24) that "[p]oppet-type
valves for use in internal combustion engines, and particularly intake poppet valves of
the type employed in automobile engines have heretofore been made employing
medium and high-carbon alloy steels by either cold or hot forging techniques." One
object of Danis' invention was to provide an improved process for forming poppet-type
engine valves employing a low-carbon steel which enables the use of simpler tooling
and further reduces wear on the tools providing greater die life with corresponding
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