Appeal No. 99-1962
Application 08/671,463
present invention, there are ribs (unnumbered)
separating the distal portion of a radial flange on
the bushing from the heat shield. Butler’s drawing
includes no radial cross section showing the ribs’
leading and trailing edge configuration, but
according to appellants, such prior art ribs
comprise squared-off edges as shown in Figures 5 and
6 of the present application. Assuming this is
true, one skilled in the art would have been well
aware of the fact that such square-edged flow
elements are prone to aerodynamic losses and
accompanied by phenomena such as the trailing edge
vortices shown in appellants’ Figure 6. The nominal
addition of aerodynamically contoured (arcuate)
leading and trailing edges to Butler’s ribs would
have simply been an obvious expedient to eliminate
such predictable losses. Moreover, the addition of
such contoured edges is consistent with conventional
streamlining techniques. The decision to apply such
techniques involves no patentable novelty; it is
nothing more than a classic engineering tradeoff
between cost and performance.
We fully appreciate the points raised by the examiner in
the answer in rejecting the appealed claims, including not
only those set forth in the above quoted explanation of the
rejection, but also those made by the examiner in the answer
in responding to appellants’ argument. Having carefully
considered appellants’ specification and claims, the teachings
of the applied reference, and the respective positions
expressed by appellants and the examiner, it is our
determination that the § 103 rejection of claims 1-3, 6-8 and
-4-
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