Appeal No. 2006-1430
Application No. 10/005,484
toward the gas flow tube 92 to close the valve by spring 115, by other high
pressure air 113’, or both (col. 10, l. 24 to col. 11, l. 6). An adjustment nut,
depicted at 123’, on threaded bolt 123 provides a means for defining the
height of the stroke of drive piston 100 as it nears the top 109 of the drive
chamber 101 (col. 13, ll. 22-26).
Appellants argue, in effect, that the drive and metering pistons of
Evans are not constructed and arranged to provide all metering positions
from fully closed to fully open because the burst of air pressure 113 quickly
moves the drive piston 100 to the top of the drive chamber 101 and the
spring 115 and/or air pressure 113’ quickly moves the piston back to the
bottom of the drive chamber. Consequently, according to Appellants,
Evans’ pistons only provide fully opened and fully closed metering
positions; “[t]here is no provision in Evans for controlling the degree to
which the valve is open” (Br. 7).
Appellants’ argument is unsound for two reasons. First, Evans’
adjustment nut and bolt 123 provide a means for controlling the degree to
which the valve is open, as it defines the height of the stroke of the drive
piston 100 and, hence, the attached metering piston 94. Second, while
Evans discloses an arrangement wherein the air pressure 113 and the
opposing force provided by the spring 115 and/or the air pressure 113’ are
balanced relative to one another so that the drive piston 100 is quickly
moved from the bottom of the drive chamber (the fully closed position) to
the top of its stroke, Evans’ valve also is fully capable, without modification,
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Last modified: September 9, 2013