Appeal No. 2004-0929
Application No. 09/386,103
Dean’s disclosure would have fairly suggested, to one of
ordinary skill in the art, mounting a cooling fan on top of
Grandmont’s heat sink to provide cooling air which flows over the
heat sink’s radial cooling fins and thereby assists in heat
removal from the heat sink.
The appellants argue that a vacuum tube is too small for the
mounting of a fan on top of Grandmont’s heat sink to be
practical, and that Grandmont does not suggest that the heat sink
provides insufficient cooling for a vacuum tube (brief, page 21).
Grandmont’s heat sink, however, is not limited to vacuum tubes
but, rather, can be used with other electronic devices that
require heat dissipation (col. 2, lines 17-20).
The appellants argue that Grandmont’s heat transfer
mechanism of interest is conduction, not convection (brief,
page 21). Dean’s heat sink conducts heat from the central region
to the cooling fins and transfers the heat away from the fins by
convection (col. 6, lines 1-4 and 41-43). One of ordinary skill
in the art would have been led by Dean to use convection to
transfer heat away from Grandmont’s cooling fins to enhance the
effectiveness of the heat sink.
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