Ex parte TATSUMI et al.

Board of Patent Appeals and Interferences

Feb 20, 1998

07758460 (B.P.A.I. Feb. 20, 1998)

Application for patent filed September 6, 1991,1
entitled "Motor-Driven Power Steering System For A Vehicle And
A Method For Controlling Same," which is a continuation of
Application 07/672,789, filed March 21, 1991, now abandoned,
which is a continuation of Application 07/265,674, filed
October 31, 1988, now abandoned, which claims the priority
benefit under 35 U.S.C. § 119 of PCT Application
PCT/JP/88/00238, filed March 4, 1988, and Japanese Application
49678/1987, filed March 4, 1987.
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THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered
today (1) was not written for publication in a law
journal and (2) is not binding precedent of the Board.
_______________
Paper No. 30
UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES

Ex parte TAKUMI TATSUMI
and MITSUHARU MORISHITA

Appeal No. 95-0744
Application 07/758,4601

ON BRIEF

Before KRASS, BARRETT, and FLEMING, Administrative Patent
Judges.
Appeal No. 95-0744
Application 07/758,460
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BARRETT, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal under 35 U.S.C. § 134 from
the final rejection of claims 19, 20, 23, and 24. Claims 4-8,
13-18, and 25-33 have been allowed, and claims 21 and 22 have
been objected to as depending on a rejected base claim.
Claims 1-3 and 9-12 have been cancelled.
We reverse.
The disclosed invention is directed to a method for
controlling a motor-driven power steering system as may be
understood from claim 19, reproduced below.
19. A control method for a motor-driven power
steering system of a vehicle, the system having a motor
connected to a steering gear by a clutch, the method
comprising:
testing the motor for mechanical restriction
with the clutch disengaged; and
engaging the clutch only if the testing
determines that the motor is not mechanically restricted.
The examiner relies on the following references:
Yabe et al. (Yabe) 4,786,866 November 22, 1988
(filed June 26, 1984)
O'Neil et al. (O'Neil) 0,174,137 March 12, 1986
(European Patent Application)
Appeal No. 95-0744
Application 07/758,460
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Yabe discloses a method and apparatus for confirming an
operating condition of a power steering device, the power
steering device including a steering mechanism driven by an
electric actuator constituted, for example, by an oil pump and
an electric motor or an electric motor alone. The motor is
temporarily operated with a quasi (test) current and an alarm
light is turned on. The motor current is measured to
determine the state of the power steering system. If the
current is above a certain value, such as 5 A, the test
current is interrupted and the alarm light is turned off and
presumably the system is operating normally, whereas if the
current is below the value the test signal and alarm light
remain on (figure 3). Alternatively, it can be determined
whether the steering system is operating properly by measuring
the variation in the oil pressure with a load sensor or by
measuring the load on the steering mechanism with a strain
gauge (col. 4, line 46, to col. 5, line 18).
O'Neil discloses a fail-safe mechanism for an electrical
power assisted steering system. A clutch is interposed
between the electric motor and the gear reduction assembly. A
control system monitors the operation of the system. When the
Appeal No. 95-0744
Application 07/758,460
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system is diagnosed to be operating improperly, the clutch is
disengaged and the motor is isolated from the steering shaft.
Claims 19, 20, 23, and 24 stand rejected under 35 U.S.C.
§ 103 as being unpatentable over O'Neil and Yabe.
The examiner's rejection is contained in the Examiner's
Answer (Paper No. 25) and appellants' position is contained in
the Brief (Paper No. 24).
Appeal No. 95-0744
Application 07/758,460
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OPINION
The claims stand or fall together (Brief, page 5).
The examiner admits that O'Neil does not teach testing
the motor with the clutch disengaged and then engaging the
clutch if the motor is determined to be operating properly
(Examiner's Answer, page 3). O'Neil appears to fall in the
same category as the discussed prior art where the clutch is
disconnected upon sensing of an extraordinarily large steering
torque or other conditions indicating that the motor has
failed or is mechanically restricted (specification, page 2).
The electric actuator of Yabe does not include a clutch and,
thus, in each embodiment, the electric actuator is tested in
its loaded state, i.e., with the electric motor operating the
oil pump to drive steering mechanism (figures 1 and 4) or
directly driving the steering mechanism (figure 5). Thus,
Yabe also does not teach testing the motor with the clutch
disengaged (it has no clutch) and then engaging the clutch if
the motor is determined to be operating properly.
The examiner finds that Yabe teaches the following
(Examiner's Answer, page 4):
Based on the magnitude of the monitored current, a
determination is made as to whether the electric motor is
Appeal No. 95-0744
Application 07/758,460
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operating properly. High current values would have
indicated mechanical restriction of the motor. . . . The
reference as a whole suggests that an abnormal load could
produce higher than normal currents flowing in the
electric motor.
Actually, Yabe determines whether the power steering system
(not just the electric motor itself) is operating properly
based on the magnitude of the monitored current. Yabe also
appears to work contrary to the examiner's understanding of
the reference. Yabe determines whether the steering system
produces sufficient load to assist the steering, as determined
by measuring the current through the electric motor (col. 4,
lines 5-31) or the oil pressure (col. 4, lines 46-58) or the
strain produced in the steering mechanism by the motor
(col. 5, lines 3-18; figure 5). For example, a high current
value in the electric motor indicates that the system is
working properly since the test current and the alarm light
are turned off if the motor current is larger than a set limit
of 5 A (figure 3, step 107): high current does not indicate a
mechanical restriction in the motor as stated by the examiner.
Perhaps the larger current indicates that the electric motor
is working normally to pump oil, whereas a low current would
indicate that the electric motor is doing less work because of
Appeal No. 95-0744
Application 07/758,460
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some malfunction, e.g., no oil in the system. Thus, we also
disagree with the examiner's statement that "Yabe et al.
suggest that abnormalities in motor current may result from
higher than normal loads, i.e. mechanical restriction caused
by the steering mechanism, and that such loads should be
considered in evaluating the operation of the electric motor"
(Examiner's Answer, page 4). While it is true that Yabe
senses an "abnormal load" as stated in the last sentence
quoted above, the abnormal load is a load which is
insufficient to assist the steering.
The examiner further finds (Examiner's Answer, page 4):
"Yabe et al. further discuss in column 5, lines 6-18 that the
load of the electric motor, i.e. steering mechanism, should be
considered to see if the load presented to the electric pump
is higher than a set value." The embodiment of figure 5
referred to at column 5, lines 6-18, determines whether the
steering system is operating normally by detecting the load on
the steering system with a strain gauge and, thus, appears to
determine mechanical restriction or motor failure by sensing
that the load provided to the steering mechanism is
insufficient. However, since the embodiment of figure 5 does
Appeal No. 95-0744
Application 07/758,460
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not detect the current through the electric motor as in the
embodiments of figures 1-4, it appears to be of little
relevance in the rejection. The steering system in figure 5
presumably operates normally if the load produced by the
electric motor, as measured by the strain gauge, is above a
certain amount, i.e., if the electric motor is producing
sufficient load to assist the steering.
Neither O'Neil nor Yabe discloses or suggests testing a
motor for mechanical restriction with the clutch engaged and
then engaging the clutch if the motor is determined to be
operating properly in either of the references. O'Neil
detects improper operation of the motor (page 8, lines 8-9),
but does not test the motor for restriction. Yabe does not
"suggest that abnormalities in motor current may result from
higher than normal loads, i.e. mechanical restriction caused
by the steering mechanism" (Examiner's Answer, page 4), as
stated by the examiner, because high motor currents are a sign
of normal operation. Therefore, we do not find any motivation
expressly or implicitly in the references to make the proposed
modification.
Appeal No. 95-0744
Application 07/758,460
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The reason, suggestion, or motivation for a modification
may come from what is known to the person of ordinary skill as
well as from a specific teaching in a reference.
See In re Oetiker, 977 F.2d 1443, 1447-48, 24 USPQ2d 1443,
1446-47 (Fed. Cir. 1992) (Nies, C.J., concurring). The
examiner attempts to analogize the problem/solution in this
case to isolating a portion of an electrical circuit for test
purposes. Appellants consider these methods to be from
nonanalogous art (Brief, pages 8-9). We agree with the
examiner that it is a fundamental engineering technique in
many fields (electrical, mechanical, and even chemical) to
isolate portions of a system for test purposes. However,
absent some indication in the references that there was a need
to test the motor for restriction before connecting it to the
power steering mechanism, it appears that the examiner is
using hindsight to work backwards towards appellants' solution
using appellants' disclosure as a guide. "The mere fact that
the prior art may be modified in the manner suggested by the
Examiner does not make the modification obvious unless the
prior art suggested the desirability of the modification."
In re Fritch, 972 F.2d 1260, 1266, 23 USPQ2d 1780, 1783-84
Appeal No. 95-0744
Application 07/758,460
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(Fed. Cir. 1982), citing In re Gordon, 733 F.2d 900. 902,
221 USPQ 1125, 1127 (Fed. Cir. 1984). It does not appear,
based on the references before us in this rejection, that the
prior art recognized the need to test a motor before
connecting it to the steering system. The references
apparently found it adequate to test the power steering system
with the motor connected to the steering gear. For these
reasons, we conclude that the examiner has failed to establish
a prima facie case of obviousness. The rejection of
claims 19, 20, 23, and 24 is reversed.
REVERSED
ERROL A. KRASS )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
LEE E. BARRETT ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
MICHAEL R. FLEMING )
Appeal No. 95-0744
Application 07/758,460
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Administrative Patent Judge )
Appeal No. 95-0744
Application 07/758,460
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