Appeal No. 2005-2154 Page 4
Application No. 10/145,341
surfaces 17, the baffle-piston being contained within a cylinder 2 attached to the nozzle
body 12 by stem 10. Pressure within the nozzle body 12 and cylinder 2 becomes
equalized and remains so as long as integral valve 2a remains closed. The interior
surfaces 17 of baffle-piston 1 are greater in projected or effective area than the effective
area of exterior surface 16. As a result, a net force is exerted to the left, as shown in
the drawings, on baffle-piston 1. This force, assisted by spring 14, retains baffle-piston
1 in a minimum opening position. When water pressure furnished to nozzle body 12
exceeds a predetermined operating pressure of the nozzle, such pressure is transmitted
through orifices 15 in the baffle-piston 1 into cylinder 2 where it acts upon valve 2a
causing valve ball 5 to unseat from valve seat 4 to relieve pressure in the cylinder 2,
thereby causing the baffle-piston 1 to move to the right and hence increasing the size of
annular opening 18. This in turn tends to reduce the pressure within the nozzle body
12.
Given the location, as seen in Figures 1 and 2 of McMillan, of the fluid passage 3
which serves as the entry port to valve 2a, it is apparent that the valve 2a is triggered
when the sensed pressure within the cylinder 2 exceeds a predetermined value. While
the sensed pressure in the cylinder 2 may bear some relation to the pressure acting on
the exterior surface 16 of the baffle-piston 1, the valve 2a does not actually sense the
pressure on the exterior surface 16. The issue in this appeal is whether such sensing of
the pressure in the cylinder is sufficient to meet the requirement in appellants’ claims 1,
17 and 19 that the pressure be relieved when the sensed pressure on a baffle forward
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Last modified: November 3, 2007