Appeal No. 2003-0400 Page 5
Application No. 09/272,772
suggestion to one of ordinary skill in the art to replace the two pumps with a single
pump of the type disclosed by Volz. We do not agree with this analysis.
From our perspective, it is not clear from Schmidt that one of ordinary skill in the
art would have been instructed by the above-quoted language to replace the two
pumps, each connected to the braking circuit of diagonal front and rear brakes, with a
single stepped piston pump with one of its chambers connected to a front brake circuit
and the other to a diagonal rear brake circuit. In fact, we are of the opinion that Volz
supports the interpretation advanced by the appellant, that is, that each of the two
return feed pumps disclosed in the cited ‘741 patent be replaced by a stepped piston
pump. The stepped pump shown in Figure 5 of Volz, upon which the examiner has
relied, both of the pumping chambers (60 and 60a) are connected through one-way
valves (62) to pump to a single outlet (unnumbered). As is explained on pages 16 and
17 of the Volz translation, an advantage of a double-acting pump is that it results in a
“relatively small pulsation in the pressure [outlet] coupling, because the quantity of
pressurizing agent conveyed per working cycle is subdivided into two conveying
strokes” (translation, page 2). One of ordinary skill in the art thus would be taught by
Volz that each of the Schmidt pumps be replaced by a double-acting (stepped) pump,
in order to smooth the pulsations that result from a single-acting pump, rather than each
be used to replace two existing pumps.
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