Appeal No. 2001-0573
Application No. 08/638,245
Claims 1 through 9 and 14 through 17 stand rejected under
35 U.S.C. § 103(a) as being unpatentable over Applicants'
Admitted Prior Art (AAPA) in view of Scales.1
Claims 1, 2, 5, 6 and 14 stand rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Scott in view of Scales.
1While the examiner has not specifically identified
exactly what is considered to be Applicants' Admitted Prior
Art (AAPA), after having reviewed the application file, we are
of the opinion that the AAPA is merely a prior art cutter or
steel-toothed cone like that described on page 2 and in lines
4-26 on page 3 of the specification and as generally shown in
Figure 1 of the application drawings, wherein selected
surfaces of each tooth have typically been hardfaced with a
wear resistant material (e.g., particles of tungsten carbide
dispersed in a steel or cobalt binder matrix) and the cutter
thereafter carburized to create a desired case depth, and then
hardened and tempered. What the AAPA does not include is any
recognition of the particular problem appellants have found in
such prior art steel-toothed cutters, i.e., that the
carburizing treatment tends to form an excess of carbon along
the relatively sharp corners defined by the intersection of
the tooth flanks and the ends of the teeth in the region near
the base or root of each tooth and that such undesirable
concentration of carbides at such locations tends to make the
teeth more brittle and more subject to fracture than the
remainder of the tooth surface, thus leading to cracking and
breakage of the teeth, especially with the increased wear
resistance of the hardfacing deposits thereon and the longer
service life of the cutter.
3
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