Appeal No. 2004-0713 Page 4
Application No. 09/900,256
obviousness is based on a single prior art reference, there must be a showing of a
suggestion or motivation to modify the teachings of that reference. See In re Kotzab,
217 F.3d 1365, 1370, 55 USPQ2d 1313, 1316-17 (Fed. Cir. 2000).
Claims 1 and 9, the independent claims on appeal, read as follows:
1. A power-assisted steering apparatus for turning steerable wheels of a
vehicle, the apparatus comprising:
a rack bar connectable with the steerable wheels of the vehicle, linear
movement of the rack bar turning the steerable wheels;
a hydraulic motor for, when actuated, moving the rack bar linearly;
a valve core rotatable to actuate the hydraulic motor; and
a one-piece, monolithic component having a pinion gear portion for
meshingly engaging the rack bar, a valve sleeve portion for cooperating with the
valve core for actuating the hydraulic motor, and a torsion bar portion having a
first end for connection with the valve core and a second end fixedly connected
to the valve sleeve portion, the torsion bar portion, in response to rotation of the
valve core to actuate the hydraulic motor, twisting relative to the valve sleeve
portion and relative to the pinion gear portion.
9. A power-assisted steering apparatus for turning steerable wheels of a
vehicle, the apparatus comprising:
a rack bar connectable with the steerable wheels of the vehicle, linear
movement of the rack bar turning the steerable wheels;
a hydraulic motor for, when actuated, moving the rack bar linearly;
a valve for controlling fluid flow to the hydraulic motor;
a rotatable tubular input shaft including a rotatable valve core, the valve
core having a plurality of axially extending grooves defining a first part of the
valve; and
a one-piece, monolithic component having a pinion gear portion for
meshingly engaging the rack bar, a valve sleeve portion forming a second part of
the valve for cooperating with the plurality of grooves of the valve core for
actuating the hydraulic motor, and a cylindrical torsion bar portion having a first
end connected with the valve core, a second end fixedly connected to the valve
sleeve portion, and an intermediate portion axially interposed between the first
end and the second end;
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