Ex Parte Fukumura

Board of Patent Appeals and Interferences

Nov 10, 2009

10455430 (B.P.A.I. Nov. 10, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte KENICHI FUKUMURA
____________

Appeal 2009-004948
Application 10/455,430
Technology Center 3600
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Decided: November 10, 2009
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Before LINDA E. HORNER, JOHN C. KERINS, and
STEVEN D.A. McCARTHY, Administrative Patent Judges.

HORNER, Administrative Patent Judge

DECISION ON APPEAL
Appeal 2009-004948
Application 10/455,430

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Kenichi Fukumura (Appellant) seeks our review under 35 U.S.C.
§ 134 of the Examiner’s decision rejecting claims 11 and 20, which are all of
the pending claims. We have jurisdiction under 35 U.S.C. § 6(b) (2002).
We REVERSE.
Appellant’s claimed invention is a rack bar for a vehicle steering
device. Spec. 1:13-14. Claim 11, reproduced below, is representative of the
subject matter on appeal.
11. A rack bar comprising:
a rack teeth portion on a surface along the length of the
rack bar;
a ball screw portion on the surface along the length of the
rack bar, wherein the ball screw portion is axially offset from the
rack teeth portion along the length of the rack bar;
wherein an entirety of the surface of the rack bar,
including the rack teeth portion and the ball screw portion, is
quench surface hardened, wherein the depth of the quench
surface hardening of the entire circumference of the rack teeth
portion is uniform and is different from the depth of quench
surface hardening of the ball screw portion.
Appellant seeks review of the Examiner’s rejection of claims 11 and
20 under 35 U.S.C. § 103(a) as being unpatentable over U.S. Patent No.
6,454,042 B1 to Yoshida, issued September 24, 2002, and Marks’ Standard
Handbook for Mechanical Engineers, Eugene A. Avallone and Theodore
Baumeister, III, Eds., 10th ed., McGraw Hill (1996) (“Marks”).
The Examiner found that Yoshida discloses the claimed rack bar but
does not disclose a specific heat treatment. Ans. 3. The Examiner
concluded that it would have been obvious to quench surface harden the
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entire circumference of the rack teeth portion of Yoshida’s rack bar
uniformly and to a different quench surface hardening depth than that of the
ball screw portion of the rack bar for the desired purpose of preventing
cracking and distortion through proper design of the rack bar for uniform
heat treatment, as taught by Marks, and to tailor the properties of the steel in
each region of the rack bar to develop properties which optimize
performance, as taught by Marks. Ans. 4-5.
Appellant contends that while Marks provides evidence of certain
well-known general principles of heat treatment, these general principles
would not have led one having ordinary skill in the art to the claimed heat
treatment whereby the depth of the quench surface hardening of the entire
circumference of the rack teeth portion is uniform. App. Br. 7.
The issue presented by this appeal is:
Has Appellant shown the Examiner erred in concluding that the
claimed rack bar, having an entire circumference of a rack teeth portion
quench surface hardened to a uniform depth, would have been obvious in
light of Yoshida and Marks?
Independent claim 11 calls for a rack bar “wherein the depth of the
quench surface hardening of the entire circumference of the rack teeth
portion is uniform.”1 Appellant argues that because the rack teeth involve
sharp corners producing stress concentrations, and because Marks teaches to
heat treat a steel part based upon optimum mechanical properties, this
teaching would have led one to quench surface harden the rack teeth

1 Claim 20, the only other claim on appeal, depends from claim 11.
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themselves to a different depth than other circumferential portions of the
rack teeth portion which do not have such teeth or are otherwise relatively
smooth. App. Br. 6-7. Thus, Appellant argues that based on the teaching in
Marks, one would not have been led to quench surface harden “the entire
circumference of the rack teeth portion” to a uniform depth as claimed.
App. Br. 7. We agree with Appellant.
Marks teaches that one can heat and cool an entire machine part at
approximately the same rate during heat treating if the part is designed to
withstand such treatment. In particular, Marks teaches:
Care must be taken in the design of a machine part to prevent
cracking and distortion during heat treatment. With proper
design the entire piece may be heated and cooled at
approximately the same rate during the heat-treating operation.
A light section should never be joined to a heavy section.
Sharp reentrant angles should be avoided. Sharp corners and
inadequate fillets produce serious stress concentration, causing
the actual service stresses to build up to a point where they
amount to two to five times the normal working stress
calculated by the engineer in the original layout. The use of
generous fillets is especially desirable with all high-strength
alloy steels.
Marks, p. 6-21 (section entitled “Relation of Design to Heat Treatment”).
Yoshida’s rack bar includes a rack teeth portion 7 that is square with
rack teeth on one side. Yoshida, col. 6, ll. 49-53; fig. 5. See also Ans. 4-5.
Yoshida’s rack teeth present sharp corners which produce stress
concentrations. One having ordinary skill in the art, based on the teaching of
Marks, would not have been led to heat treat the entire rack teeth portion of
Yoshida’s rack bar at the same rate during heat treating. Thus, the combined
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teaching of Yoshida and Marks would not have led one having ordinary skill
in the art to a rack bar “wherein the depth of the quench surface hardening of
the entire circumference of the rack teeth portion is uniform” as claimed.
Accordingly, Appellant has shown the Examiner erred in concluding
that the claimed rack bar, having an entire circumference of a rack teeth
portion quench surface hardened to a uniform depth, would have been
obvious in light of Yoshida and Marks.
The decision of the Examiner to reject claims 11 and 20 is reversed.

REVERSED

Vsh

OBLON, SPIVAK, MCCLELLAND,
MAIER & NEUSTADT, L.L.P.
1940 DUKE STREET
ALEXANDRIA VA 22314