Appeal No. 1999-0405
Application No. 08/651,571
Appellants’ invention is directed to a molten metal
impeller (e.g., claims 1, 9, 14 and 20) and to a shaft for a
molten metal impeller (claim 19). In the paragraph bridging
pages 2 and 3 of their specification, appellants indicate that
historically, a bearing ring is cemented to both the shaft and
molten metal impeller. More particularly, appellants note
that a typical impeller (usually formed of graphite) has a
generally cylindrical portion which is machined to include a
notched periphery, with a bearing ring (often of silicon
carbide) cemented into the notch. Appellants observe that such
prior art designs have remained a frequent area of failure
because the joint is incompletely filled with cement and the
graphite to cement adherence is relatively poor.
To increase the useful operable life of a molten metal
pump and increase its overall reliability, appellants have
claim 1. Appellants should correct this oversight during any
further prosecution of this application before the examiner.
We also note that there does not appear to be any proper
antecedent basis for "said adhesive joint" in line 3 of claim
6.
2
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