Ex parte Heimberg

Board of Patent Appeals and Interferences

Jun 23, 2000

08676907 (B.P.A.I. Jun. 23, 2000)

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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journal and (2) is not binding precedent of the Board.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. 19
UNITED STATES PATENT AND TRADEMARK OFFICE
________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
________________
Ex parte WOLFGANG HEIMBERG
________________
Appeal No. 1998-1503
Application No. 08/676,907
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ON BRIEF
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Before HAIRSTON, KRASS, and RUGGIERO, Administrative Patent
Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of
claims 2 and 3, the only claims pending in the application.
Appeal No. 1998-1503
Application No. 08/676,907
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The invention is directed to a circuit for driving an
excitation coil of an electromagnetically driven reciprocating
pump for use in a fuel injection device.
Independent claim 2 is reproduced as follows:
2. A reciprocating pump used as a fuel injection
device, comprising:
an excitation coil which is driven by an excitation
current;
an armature operatively associated with the excitation
coil for operating a fluid-displacement element of the pump;
and
an excitation circuit operative for supplying current
pulses to the excitation coil, the excitation circuit
comprising:
a power transistor in series with the excitation coil and
with a measuring resistor having a side connected to the
transistor;
a comparator having an output and two inputs, the output
being connected to a control input of the transistor;
one input of the comparator being responsive to a
selectively variable reference signal corresponding to a
predetermined target current in the excitation coil; and
the other input of the comparator being connected to the
side of the measuring resistor that is connected to the
transistor and thus being responsive to the actual current
through the excitation coil, so that the comparator compares
the actual current and the target current and operates to
drive the transistor to adjust the actual current to the
Appeal No. 1998-1503
Application No. 08/676,907
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target current, and to turn off the current through the
excitation coil when the actual current exceeds the target
current, so that the current through the excitation coil is
repeatedly switched off and on as long as the reference signal
prevails at the one input of the comparator,
whereby the excitation coil is controlled by both the
duration and amplitude of the reference signal to the
comparator.
The examiner relies on the following references:
Takahashi
4,377,144 Mar. 22, 1983
Suquet 4,944,281 Jul. 31, 1990
In addition, the examiner relies on admitted prior art [APA],
at page 1 of the specification, regarding the notoriety of
using reciprocating pumps to drive fuel injectors.
Claims 2 and 3 stand rejected under 35 U.S.C. § 103 as
unpatentable over Suquet in view of APA and Takahashi.
Reference is made to the briefs and answer for the
respective positions of appellant and the examiner.
OPINION
We reverse.
Appeal No. 1998-1503
Application No. 08/676,907
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We have reviewed the evidence before us, including, inter
alia, the arguments of appellant and the examiner and the
applied references and we conclude therefrom that although the
examiner has established a prima facie case of obviousness
with regard to the claimed subject matter, shifting the burden
to appellant, appellant has presented an argument against the
prima facie case which has not, in our view, been adequately
addressed by the examiner. Accordingly, while we find the
decision here to be a close call, we are constrained to find
for appellant.
More specifically, the examiner has applied Suquet to
show circuitry for regulating current in an inductive load.
That circuitry, shown in Suquet’s Figure 2A, for example,
includes the claimed transistor, comparator and measuring
resistor connected in a like manner to achieve a similar
result but for the claimed “selectively variable reference
signal” and the claimed “reciprocating pump.” The examiner
relies on Takahashi to show a variable reference voltage by
showing a two level reference voltage and argues that it would
have been obvious to employ such a variable reference signal
in the circuit of Suquet. We do not disagree and, in fact, in
Appeal No. 1998-1503
Application No. 08/676,907
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our view, even without Takahashi, it appears to us that the
skilled artisan would have recognized that the fixed reference
voltage, 6, of Suquet may be made variable when it is desired
to change the signal to which the measured signal is compared.
Thus, allowing the reference signal in Suquet to be variable
would have enabled the artisan to control the amplitude of the
current flowing in the inductive load. The examiner also
relies on APA in contending the obviousness of employing a
well known reciprocating pump for the inductive load, 1, of
Suquet, especially in view of Suquet’s disclosure (column 1,
lines 16-17) that the patented device is applicable to the
solenoid valves of fuel injectors.
The examiner’s reasoning, at first blush, appears
reasonable and the examiner’s explanation of the applicability
of the applied references and reasons for combining the
references establishes, in our view, a prima facie case of
obviousness.
At this point, the burden was shifted to appellant to rebut,
by persuasive argument and/or objective evidence, the prima
facie case of obviousness.
Appeal No. 1998-1503
Application No. 08/676,907
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Appellant has argued that neither Suquet nor Takahashi is
directed to a reciprocating pump, as claimed. Appellant
explains that while these two references are directed to
devices within the field of fuel injection, they are directed
to the opening and closing of a valve. We agree. The opening
and closing of a solenoid valve, as in Suquet and/or
Takahashi, is determinative of the duration of the time in
which the valve is open/closed. The examiner has pointed to
nothing within the teachings of Suquet or Takahashi that would
indicate that the excitation coil, or inductive load, is also
controlled, in addition to duration of a reference signal, by
the amplitude of the reference signal.
Appellant argues that the opening/closing of a valve in
Suquet and Takahashi allows fuel “already under pressure” to
flow into a combustion chamber. The examiner dismisses this
argument by contending that the argument is not directed to
claimed subject matter. While we agree with the examiner that
the claims say nothing about fuel “already under pressure,” we
believe appellant is merely attempting to draw a distinction
between the operation of a reciprocating pump, as claimed, and
the valve opening and closure taught by Suquet and Takahashi.
Appeal No. 1998-1503
Application No. 08/676,907
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That is, the instant claims are specifically directed to a
reciprocating pump used as a fuel injection device and that
pump comprises an excitation circuit for supplying current
pulses to an excitation coil and the excitation coil is
controlled by both the duration and amplitude of the reference
signal to the comparator. If we understand appellant’s
position, it is that the reciprocating pump would create the
pressure which the fuel is under when it flows into the
combustion chamber whereas the opening and closure of a
solenoid valve, as in Suquet and Takahashi, allows the fuel,
which is already under pressure, to flow into the combustion
chamber. Therefore, the reciprocating pump to which the
instant claims are directed would be upstream of the solenoid
valves to which Suquet and Takahashi are directed. As such,
appellant argues, it would not have been obvious to substitute
a solenoid operated pump for the solenoid valve in Suquet and
then substitute the valve-controlled circuit of Takahashi for
the valve-control circuit of Suquet and then modify those
circuits as required by claims 2 and 3. Appellant states, at
page 8 of the principal brief, “Such a substitution is neither
Appeal No. 1998-1503
Application No. 08/676,907
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logical nor plausible, given the different purposes and
operation of a solenoid valve vs. a solenoid pump.”
The examiner’s response is merely to state that the type
of inductive load is “immaterial” and that it would have been
obvious to substitute a reciprocating pump for the inductive
load, 1, of Suquet. While there may be some reason, of which
we are unaware, for substituting a reciprocal pump for the
inductive load of Suquet, the examiner’s rationale that it
would have been obvious to substitute a reciprocal pump for
the inductive load of Suquet merely because reciprocal pumps
were known is not sufficient in view of appellant’s argument
that the examiner’s substitution is illogical in view of the
different purposes and operation of a solenoid valve and a
reciprocating pump. The examiner has not sufficiently
responded to appellant’s apparently reasonable argument. As
such, weighing the evidence before us on this record, we are
constrained to find for appellant. That evidence indicates a
strong argument by appellant as to why reciprocating pumps are
different than solenoid valves and that it would not have been
obvious to substitute one for the other, versus the examiner’s
unsupported contention that it would have been obvious to
Appeal No. 1998-1503
Application No. 08/676,907
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substitute a reciprocating pump for the inductive load taught
by the prior art. The instant claims explicitly call for a
reciprocating pump used as a fuel injection device comprising
the remaining claimed elements. The examiner’s argument that
it would have been obvious to employ the circuitry of Suquet
and Takahashi with a reciprocating pump because of a mere
substitution of a pump for the inductive device shown by
Suquet is overcome by appellant’s argument that the different
purposes and operation of a reciprocating pump would not have
led the skilled artisan to make such a substitution.
The examiner’s decision rejecting claims 2 and 3 under
35 U.S.C. § 103 is reversed.
REVERSED
KENNETH W. HAIRSTON )
Administrative Patent Judge )
)
)
)
)
ERROL A. KRASS ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
Appeal No. 1998-1503
Application No. 08/676,907
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)
)
)
JOSEPH F. RUGGIERO )
Administrative Patent Judge )
ek/rwk
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