Appeal No. 1996-1897
Application 08/064,145
Mushardt FIG. 1), which “turbine blades” constitute “a power unit blade having a blade with a leading
edge, trailing edge, blade axis, blade base, blade tip and blade center” as specified in appealed claim
20.
We find that Mushardt states the following with respect to enclosing a workpiece (page 2, lines
82-108; emphasis supplied):
One feature of the invention resides in the provision of a cast fixture or jog which consists
of meltable material and serves to hold and clamp composite workpieces, particularly
workpieces including twin turbine blades and defining internal compartments. The improved
fixture comprises a plurality of spaced-apart components in the form of walls or the like
which define a space for a selected portion of a composite workpiece, and a connector (e.g.,
a connector consisting of two or more spaced-apart ribs or webs) which connects the
compartments to each other in such a way that the compartment is a least substantially
free of meltable material of the fixture. If the workpiece which is disposed in the space
defined by the components of the fixture has one or more undercut portions (e.g., in the
regions of the edges of turbine blades or in the regions where the blades are connected to
each other by portions of the inner and outer vane rings) which are adjacent to the
components , the mutual portions of the components and of the web or webs of the connector
are selected in such a way that each undercut portion is at least substantially free of meltable
material of the fixture.
Mushardt exemplifies this concept with the following embodiment (page 4, lines 38-103; emphasis
supplied):
FIGS. 1 to 6 show a fixture or jig 6 for holding a composite workpiece including two
spaced-apart (outer and inner) [turbine] blades 1, 2 . . . [which] are integrally connected with
an inner ring segment 3 and an outer ring segment 4 . . . [that] together define a compartment
12. The fixture 6 comprises two spaced apart components or walls 7 and 8 and a
connector including two spaced apart ribs or webs 9, 11 each of which is integral with
the components 7 and 8. The components 7 and 8 are outwardly adjacent to the blades 1
and 2 (see particularly FIGS. 2 and 4) so that the component 7 is adjacent to the convex
outside of the outer blade 1, and the component 8 is adjacent to the concave outer side of
the inner blade 2. The webs 9 and 11 extend into the compartment 12 but the remainder
of this compartment [12] is devoid of the material of the fixture 6. The compartment 12 is also
devoid of the material of the fixture 6 in the regions of the front and rear edges 13, 14 of the
blade 1 as well as in the regions of the front and rear edges 16, 17 of the blade 2 (FIGS. 2
and 4). . . . The workpiece is normally treated by one or more grinding wheels or by other
suitable tools, in the regions of its segments 3 and 4, i.e., the tool or tools remove material
from those portions of the workpiece which are not confined in the fixture 6. An advantage
of the feature that the compartment 12 extends all the way to the edges 13, 14 and 16, 17 of
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