Appeal No. 97-0990 Page 8
Application No. 08/105,093
with the sealing surfaces such that the first wall exerts a first
sealing force against the first sealing surface and the second
wall exerts a second sealing force against the second sealing
surface, and (3) a third seal element extending circumferentially
about the axis A and having a surface extending radially to
engage the front of the first seal element. The seal is adapted
by the second seal element means to block the leakage of fluid
from the first region by urging the sidewalls against the sealing
surfaces. The seal is also adapted by the opening between the
two sidewalls to allow pressurized fluid from the second region
to exert a sealing force against the sidewalls to augment the
sealing force from the second seal element means under operative
conditions at which the pressure of the second region
substantially exceeds the pressure of the first region and the
third seal element positions the first seal element in the axial
direction to resist the pressure force from the second region.
The examiner determined (final rejection, pp.4-5) that
[i]t would have been obvious to one of ordinary skill in the
art to substitute the seal assembly of Smetana for the o-
ring seal of Voitik in order to provide a seal with the
ability to respond to fluid pressure in order to provide a
better seal.
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Last modified: November 3, 2007