Appeal No. 2002-0538
Application 09/220,468
outer shroud of the compressor section substantially adjacent to
one row of rotating blades and in fluid communication with the
turbine section for extracting air from the tip clearance of the
blades to be routed to the turbine section to increase stability
of the engine. Although Uehling does not specify the nature of
the interface between the compressor 14 and the pipe 24, it is
not disputed that this interface must include at least one
opening in the shroud (housing 12). Uehling’s Figure 3, which
shows bypass pipe 24 communicating with the compressor 14 through
the shroud at a position adjacent the tip clearance area of a row
of rotating blades, belies the appellant’s argument that “Uehling
does not teach that the bleed air is extracted through an opening
that is substantially adjacent to a row of rotating blades” (main
brief, page 7). Although patent drawings are not working
drawings, things shown clearly therein are not to be disregarded,
even if unexplained by the specification. In re Mraz, 455 F.2d
1069, 1072, 173 USPQ 25, 27 (CCPA 1972). Due to its position,
Uehling’s opening(s) would necessarily extract air from the tip
clearance area of the rotating blades, and the resulting
reduction in tip clearance leakage would inherently increase the
stability of the engine to the same extent that the extraction of
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