Appeal No. 2006-2338 Page 5
Application No. 10/326,449
We find explicit motivation in the Taylor reference itself to combine its
teaching with the common inverted L-shaped overflow system that would have led
one of ordinary skill in the art to the claimed invention. In particular, as noted by
the examiner on page 3 of the Answer, Taylor teaches that it was known in the
prior art to use an expandable plug, such as a dollar plug with an expandable
rubber “accordion” washer, to seal an overflow drain port during pressure testing.
Taylor, col. 1, lines 15-36. We find, thus, that Taylor teaches using the same
expandable plug for the same purpose of sealing an overflow drain port during leak
testing as in the claimed invention. One having ordinary skill in the art at the time
the invention was made, possessed with the teaching of Taylor and the knowledge
that L-shaped overflow systems were common in the art, would have been led to
apply an expandable plug to an L-shaped overflow system to seal the overflow port
during testing, because the L-shaped overflow system is just another type of
commonly-used drain overflow system, on which leak testing must be performed.
As such, it would have been obvious to one having ordinary skill in the art at the
time the invention was made to have used such an expandable plug on a common
inverted L-shaped overflow drain system in order to perform leak testing as taught
by Taylor.
The appellant also argues that there is no motivation to use an expandable
plug as claimed to seal the overflow drain port, because Taylor discourages the use
of expandable plugs for this purpose due to their tendency to blow out under
pressure. Brief, p. 9. Even if Taylor discourages the use of expandable plugs for
the purpose of pressure testing, it still does not remove the fact that expandable
plugs had been used in the prior art for this purpose. See In re Gurley, 27 F.3d
551, 553, 31 USPQ2d 1130, 1132 (Fed. Cir. 1994) (“A known or obvious
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