Ex Parte Perkinson et al

Patent Trial and Appeal Board

May 3, 2013

11370344 (P.T.A.B. May. 3, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte ROBERT H. PERKINSON, PETER J. DOWD, and
PAUL A. CARVALHO
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Appeal 2011-003813
Application 11/370,344
Technology Center 3700
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Before: JAMES P. CALVE, WILLIAM A. CAPP, and
JEREMY M. PLENZLER, Administrative Patent Judges.

PLENZLER, Administrative Patent Judge.

DECISION ON APPEAL

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Application 11/370,344

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STATEMENT OF CASE
Appellants seek our review under 35 U.S.C. § 134 of the Examiner’s
decision rejecting claims 1-11 under 35 U.S.C. § 103(a) as being
unpatentable over Covert (US 2,958,382; iss. Nov. 1, 1960), Carvalho (US
5,836,743; iss. Nov. 17, 1998), and Capewell (US 6,685,382 B2; iss. Feb. 3,
2004). We have jurisdiction under 35 U.S.C. § 6(b).
We REVERSE.

CLAIMED SUBJECT MATTER
Claim 1 is the sole independent claim and is reproduced below:
1. A propulsor system comprising:
a coarse pitch pressure circuit which supplies a coarse
pitch pressure;
a fine pitch pressure circuit which supplies a fine pitch
pressure;
a pitchlock pressure circuit which supplies a pitchlock
pressure;
a yoke assembly mounted along an axis of rotation, said
yoke assembly including a pitch change actuator piston which
separates a coarse pitch actuator chamber and a fine pitch
actuator chamber, said coarse pitch actuator chamber
pressurized by the coarse pitch pressure and said fine pitch
actuator chamber pressurized by the fine pitch pressure;
a pitchlock piston which separates a pitchlock piston
pitchlock pressure chamber and a pitchlock piston coarse pitch
pressure, said pitchlock piston pressure chamber pressurized by
the pitchlock pressure and said pitchlock piston coarse pitch
chamber pressurized by the course pitch pressure circuit;
a pitchlock ballscrew screw mounted along an axis of
rotation, said pitchlock ballscrew screw having an external
screw ball track groove, said pitchlock ballscrew screw axially
movable along said axis of rotation in response to axial
movement of said pitchlock piston;
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a pitchlock nut mounted about said ballscrew screw, said
pitchlock nut having an internal pitchlock nut thread;
a ballscrew ballnut mounted about said pitchlock
ballscrew screw and axially adjacent said pitchlock nut, said
ballscrew ballnut includes an internal ballnut track groove;
a ballscrew ballnut spring which biases said ballscrew
ballnut toward said pitchlock nut, said ballscrew ballnut spring
collapsible such that said pitchlock ballscrew screw is movable
between an operational position and a pitchlock position, said
internal pitchlock nut thread lockable with said external screw
ball track groove in said pitchlock position; and
a pitchlock solenoid valve in communication with the
pitchlock pressure circuit, said pitchlock solenoid valve
selectively operable to dump the pitchlock pressure such that
said pitchlock ballscrew screw moves toward said pitchlock
position.

OPINION
The Examiner finds that Covert teaches each of the features of claim 1
except the yoke assembly, the pitchlock solenoid valve, and the pitchlock
nut. Ans. 4-5. The Examiner cites Carvalho as teaching these additional
features and reasons that it would have been obvious “to modify the
invention of Covert by utilizing a single actuator assembly with a yoke
arrangement as taught by Carvalho for the purpose of simplifying the pitch
control system as well as reducing the size of the system.” Ans. 5.
Appellants explain that the Examiner’s proposed modification to
Covert would require using one of the pitch locking mechanisms from an
individual one of the propeller blades in Covert and rotating the pitch
locking mechanism ninety degrees. App. Br. 6. As Appellants point out,
this changes the rotational axis about which the pitch locking mechanism is
rotated during operation, as well as the orientation of the pitch locking
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mechanism relative to the axis of rotation. App. Br. 6-7; Reply Br. 2.
Appellants argue that the proposed modification would render Covert
unsatisfactory for its intended purpose. App. Br. 5-7; Reply Br. 2.
It is unclear why one skilled in the art would be inclined to change the
rotational axis of the pitch locking mechanism of Covert when the pitch
locking mechanism is specifically designed for operation within a propeller
blade. Covert relies on centrifugal force to hold each propeller blade locked
in a pitch position in the event of a hydraulic system failure. See Covert,
col. 4, l. 68 – col. 5, l. 4. Lock release plunger 60 is normally biased
outward by hydraulic pressure to allow pitch adjustment. Covert, col. 4, ll.
56-67. However, when the hydraulic system fails the lock release plunger
60 is no longer biased outward by hydraulic pressure and the centrifugal
force acting on the flyweights 64, 65 is transferred to the lock release
plunger 60, forcing the shoulder 43 into frictional engagement with the
member 45 and locking the pitch position of the propeller blade. Covert,
col. 4, l. 68 – col. 5, l. 4.
As explained by Appellants, the force applied to the flyweights is
altered due to the modified orientation of the flyweights relative to the axis
of rotation in the Examiner’s proposed modifications to Covert. App. Br. 6-
7; Reply Br. 2. The magnitude of the force is also significantly reduced in
Examiner’s proposed modified Covert due to the reduced distance between
the flyweights and the axis of rotation providing a velocity reduction for the
flyweights. Thus, we are not convinced that one skilled in the art would be
motivated to modify Covert as suggested by the Examiner as a simplification
of the pitch control actuator assembly (see Ans. 7) when the modification
would change the operation of Covert or would undertake to do so with a
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reasonable expectation of success. Neither are we persuaded that Covert
would function in the modified orientation proposed.
For these reasons, we do not sustain the rejection of claims 1-11.

DECISION
We REVERSE the Examiner’s decision to reject claims 1-11.

REVERSED

JRG