Appeal No. 1999-2399
Application 08/705,798
12a do not reduce the torsional flexibility of the beam
(Br7-8).
The Examiner finds that "[t]he second purpose of
brace 12a [in Kikuchi] is to reduce or prevent beam 12 from
being torsionally flexible, e.g. twisting or turning" (EA8)
because otherwise the transducer 11 would not fly properly.
We find nothing in Kikuchi to support this finding.
The Examiner further finds that since "braces 12a cannot
bend up or down as easily along a lateral direction, they are
torsionally stiff as required by the claims" (EA9).
We agree with the Examiner's conclusion, if not his
reasoning. The structural analysis of torsion is difficult
with anything other than cylindrical and cylindrical shell
members symmetrically located with respect to the torsional
axis. Nevertheless, for empirical reasons, we find that the
bent sections 12a inherently provide increased torsional
stiffness. The torsional stiffness around the longitudinal
axis is related to the cross-sectional area of the beam in the
transverse plane which resists the twisting. Consider two
cross-sectional areas: one through the flat portion of
beam 12 and one through the bent portion 12a as shown below.
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