Appeal No. 97-2486
Application No. 08/308,983
Stasz et al. 4,862,890 Sep. 5, 1989
(Stasz)
Eggers (EP) 0 518 230 Dec. 16, 1992
Claims 37-39 stand rejected under 35 U.S.C. § 103 as
being unpatentable over Eggers in view of Horton. The
examiner considers that it would have been obvious to form the
conductive bodies of the end effectors 18, 19 of Eggers (see
the embodiment of Fig. 6A) by an investment casting process3
in view of the teachings of Horton.
3According to the McGRAW-HILL ENCYCLOPEDIA OF SCIENCE AND
TECHNOLOGY, McGraw-Hill, Inc., New York, N.Y., 1971, Vol. 2,
p. 568:
In investment casting (lost-wax process) a wax or
frozen mercury pattern is made; it is then dipped
into a slurry of a refractory coating material such
as silica and into liquids including water, ethyl
alcohol, and acids. After the coating has dried,
the pattern assembly is placed in a flask and filled
with molding mixtures such as sand, water, and a
binder. After the mold has dried in air, the wax is
melted out by inverting and heating it between 200
and 300EF. Depending on the metal, the mold is then
heated between 1200 and 1900EF for burnout (to drive
off all gases) and for preheating, after which the
molten metal is poured into the mold. After
solidification of the casting, the mold is broken
away and the casting is removed. The process is
costly, but gives good surface finish and close
tolerances, is suitable for casting high-melting-
point alloys, and can be used for intricate shapes.
3
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