Appeal No. 1997-1731
Application No. 08/377,924
have is that the applied references, by themselves, would not
have motivated one having ordinary skill in the art to modify
the Siard or Briggs ‘526 patents, as proposed. As we see it,
each of Teutsch and Briggs ‘775 would have simply been
perceived by one of ordinary skill as distinct alternatives
for effecting uniformity in an article being extruded. More
specifically, as recognized by the examiner (answer, page 6),
Teutsch instructs those versed in the art as to the benefit of
helical grooves of decreasing depth in combination with
conical surfaces that coact with one another to effect a
conical passage that increases from its inlet to its outlet. 2
On the other hand, Briggs ‘775 informs those skilled in the
art as to the practice of interfacing tapered passages alone
to effect a lesser downstream diameter and achieve laminar
flow and reduced turbulence (column 7, lines 19 through 26).
Based upon the aforementioned disclosures, it is clear to us
that the proposed combination of teachings can only be
2In appellant’s specification (page 3), it is indicated
that “[s]o far as presently known” die apparatus have not
employed helical or spiral grooves on the conical surfaces of
die elements. The applied patent to Teutsch teaches such a
die apparatus.
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