Appeal No. 1998-0863
Application 08/502,831
In view of this disclosure, we consider that one of ordinary
skill in the art would have appreciated that the housing 22 of
Krichton’s heater (including the top portion 26) would remain
relatively cool, thereby allowing the housing to be formed of
materials, such as thermoplastic, which are less heat-
resistant than sheet metal. This is particularly brought out
by Krichton’s disclosure concerning handle 90, which is
located on the top 26 of the heater. As described in col. 3,
lines 8 to 18, the handle is preferably molded of plastic and
is normally held down against the top surface of top panel 26
by springs 94. This disclosure of a molded plastic part
maintained in direct contact with the top 26 of Krichton’s
heater would have suggested to one of ordinary skill that top
26 would not be so hot as to adversely affect molded plastic.
Accordingly, we agree with the examiner that it would
have been obvious to modify the Krichton heater by making the
top (cap) out of a molded thermoplastic material, as claimed.
Taking Krichton’s disclosure, as discussed above, in light of
(a) the well-known advantages of plastic over sheet metal,
e.g., plastic is moldable, does not rust, and need not be
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