Ex Parte Cripe

Board of Patent Appeals and Interferences

Aug 21, 2009

11352749 (B.P.A.I. Aug. 21, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte DAVID W. CRIPE
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Appeal 2009-003114
Application 11/352,749
Technology Center 2800
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Decided: August 21, 2009
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Before BRADLEY R. GARRIS, BEVERLY A. FRANKLIN, and
MARK NAGUMO, Administrative Patent Judges.

NAGUMO, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2009-003114
Application 11/352,749

A. Introduction1
David W. Cripe (“Cripe”) timely appeals2 under 35 U.S.C. § 134(a)
from the final rejection3 of claims 1-18. We have jurisdiction under
35 U.S.C. § 6. We REVERSE.
The subject matter on appeal relates to magnetoelastic torque sensors
that are said to be designed to attenuate the deleterious effects of magnetic
hysteresis on the output signal. The record indicates that torque sensors are
useful, for example, for measuring the torque in power steering systems in
automobiles.
Representative Claim 1 is reproduced from the Claims Appendix to
the Principal Brief on Appeal:
1. A magnetometer assembly comprising:
a first inner coil and a second inner coil disposed about a
common axis and separated axially;
a first outer coil disposed concentrically about the first
inner coil and a second outer coil disposed concentrically
about the second inner coil;
a first plurality of magnetically saturable wires disposed
parallel to the common axis between the first inner coil
and the first outer coil; and

1 Application 11/352,749, Demagnetization-Field Enhancing
Magnetometer, filed 13 February 2006, claiming the benefit under
35 U.S.C. § 119(e) of provisional application 60/707,927, filed 12 August
2005. The specification is referred to as the “749 Specification,” and is cited
as “Spec.” The real party in interest is listed as Continental Automotive
Systems U.S., Inc. (Reply Brief, filed 9 July 2008 (“Reply Br.”), 1.)
2 Appeal Brief, filed 21 April 2008 (“Br.”).
3 Office action mailed 21 November 2007 (“Final Rejection”; cited as
“FR”).
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Application 11/352,749

a second plurality of magnetically saturable wires
disposed parallel to the common axis between the second
inner coil and the second outer coil.
(Claims App., Br. 9; indentation added.)
The Examiner has maintained the following ground of rejection:4
Claims 1-18 stand rejected under 35 U.S.C. § 103(a) in
view of the combined teachings of Viola5 and
Cripe 403.6
The issue dispositive of this appeal is whether, as Cripe contends,
substitution of the magnetically saturable wires 28 taught by Cripe 403
would destroy a critical intended purpose of the magnetically saturable
foils 44 taught by Viola. (Br. 5.) According to Cripe, the purpose and mode
of operation of the torque sensor taught by Viola is to “provide a detector
that is not circumferentially limited in angular measurements.” (Id., citing
Viola, paras. 5-8.) In the Viola embodiment 40, illustrated in Figures 5-7,
on which the Examiner relies, this goal is accomplished by using continuous
foil element 44 that “is non-interrupted about the circumference of the
shaft 50.” (Br. 5.) Cripe argues that the magnetically saturable wires 28
taught by Cripe 403 cannot encircle the shaft as does the foil element 44, and
therefore are not a proper substitute for the foil element.

4 Examiner’s Answer mailed 12 May 2008. (“Ans.”).
5 Jeffrey L. Viola et al., Magnetoelastic Torque Sensor for Mitigating Non-
Axisymmetric Inhomogeneities in Emanating Fields, U.S. Patent Application
Publication US 2004/0007083 A1 (15 January 2004).
6 David W. Cripe, Magnetoelastic Torque Sensor, U.S. Patent Application
Publication US 2002/0162403 A1 (2002).
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The Examiner maintains that “[t]he use of wires from Cripe [403]
would not destroy the intended purpose of Viola since the main structure (as
shown in Figures 6 and 7) of a shaft along with the positions of the coils and
foil element does not change.” (Ans. 7-8.) The Examiner dismisses Cripe’s
arguments because “the circumferential angular coverage desired is not
currently claimed by the Appellant.” (Id.) Moreover, the Examiner
maintains that “[t]he wires as taught by Cripe would encircle the shaft of
Viola.” (Id.)
B. Findings of Fact
Findings of fact throughout this Opinion are supported by a
preponderance of the evidence of record.
The 749 Specification
1. According to the 749 Specification, magnetic torque sensors include a
force transducer element that produces a magnetic field in response to the
application of force. (Spec. 1, ¶ [0003].)
2. The 749 Specification teaches that magnetic field-based torque
sensors operate in part by passing an alternating current through a coil
causing periodic saturation of a core of magnetically saturable material.
(Spec. 1-2, ¶ [0004].)
3. Changes in the inductance of the coils due to the magnetic saturation
are said to result in the induction of a voltage to the coils that can be
measured to determine the amplitude and direction of force applied to the
force transducer element. (Spec. 1-2, ¶ [0004].)
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4. A magnetic hysteretic effect is said to be observed in which the zero-
torque magnetic field from the transducer does not return to zero amplitude
when the stimulating torque (force) is applied and then removed. (Spec. 2,
¶ [0005].)
5. An object of the disclosed invention is said to attenuate the effects of
magnetic hysteresis in the operation of the magnetometer. (Spec. 2,
¶ [0006].)
6. The 947 Specification teaches that this goal is accomplished by
“generating a counter-magnetic filed opposing that generated by the
transducer so that the net magnetic field within both the magnetically
saturable elements and the magnetoelastic transducer so that the magnetic
flux within the transducer is kept to a minimum of amplitude.” (Spec. 4,
¶ [0011].)
7. In the described torque sensors (not reproduced here: see Fig. 1 or
Fig. 4), a coil assembly surrounds a rotable shaft 14, which is disposed along
axis 20, and which supports a “ring” (i.e., a sheath) of magnetoelastic
material 16. (Spec. 5, ¶ [0018].)
8. An embodiment of the coil assembly recited in claim 1 is shown in
cross section in Figure 3, which is reproduced on the following page:
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Application 11/352,749

{749 Specification Figure 3 is shown below:}

{947 Specification Figure 3 is said to show a coil assembly}
9. Bobbin 24 supports, in a first axial region 26, first inner coil 36, first
outer coil 38; and in second axial region 28, second inner coil 40 and second
outer coil 42. (Spec. 5, ¶ [0019].)
10. The inner and outer coils are separated by a plurality of magnetically
saturable wires 44 having a very high length to diameter ratio that are
dispersed in equal angular segments about the bobbin 24 and concentrically
with axis 20. (Spec. 5, ¶ [0020].)
Viola
1. According to Viola, magnetic anomalies in the rotating shaft of a
torque sensor result in undesirable anomalous output signals. (Viola 1,
¶ [0005].)
2. In Viola’s words,
[w]hen the inhomogeneities in the magnetic field are sensed
by the magnetic field sensors configured in an
circumferentially limited angular expanse about the shaft, the
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Application 11/352,749

detector produces a deviation in the output signal that is
erroneously interpreted as a change in direction and/or
magnitude of the torque transmitted to the shaft.
(Viola 1, ¶ [0005].)
3. In the embodiment shown in Figures 1-3 (not reproduced here), Viola
describes a torque sensor 10 in which employs a plurality of coil pairs 14
that are wrapped in opposite directions around the same or another
magnetically saturable core element 18. (Viola 2, ¶¶ [0029]-[0033].
4. Viola teaches:
[b]y positioning coil pairs 14 circumferentially around the
rotatable shaft 12, effects of inhomogeneities in the magnetic
field emanating from the shaft 12 resulting from anomalies in
the magnetic alloy of the shaft 12 can be reduced. By
positioning the coil pairs 14 closely together, effects of the
inhomogeneities in the magnetic field emanating from the
shaft 12 can be substantially eliminated.
(Viola 2, ¶ [0033]; emphasis added.)
5. Viola describes torque sensor 40, which is illustrated in Figure 6,
which is reproduced on the following page:
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Application 11/352,749

{Viola Figure 6 is shown below}

{Viola Figure 6 is said to show a torque sensor in longitudinal cross section}
6. Torque sensor 40 comprises a rotatable shaft 50 with magnetic alloy
layer 50a, surrounded by bobbin 52, which has “grooves” 52a and 52b.
(Viola 3, ¶¶ [0035]-[0036].)
7. Grooves 52a and 52b support first and second coils 42a and 42b,
respectively. (Viola 3, ¶ [0036].)
8. Both coils 42a and 42b comprise inner coil winding 46, and
oppositely wound outer coil winding 48. (Viola 3, ¶ [0035].)
9. Moreover, each coil 42a, 42b has a foil core element 44, which is
supported between inner coil winding 46 and outer coil winding 48.
(Viola 3, ¶ [0035].)
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Application 11/352,749

10. The continuous character of foil core element 44 is also illustrated in
Figure 7, which is reproduced below:
{Viola Figure 7 is shown below}

{Viola Figure 7 is said to show a torque sensor in axial cross section}
11. In Viola’s words, “[t]he foil core element 44, which is the active
sensing component of the magnetic field sensing element, completely
encircles a rotatable shaft 50, thereby providing the circumferential angular
coverage desired of the sensing element.” (Viola 3, ¶ [0035]; emphasis
added.)
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Application 11/352,749

Cripe 403
12. According to Cripe 403, prior art magnetic field-based torque sensor
comprise “two or more sets of oppositely-oriented magnetic field sensors
located over each of the active regions of a rotatable magnetic shaft.”
(Cripe 403 1, ¶ [0006].)
13. Cripe 403 teaches that the outputs of the sensors, which are positioned
in an equiangular distribution around the shaft, are averaged to attenuate
signal resulting from the rotation of the shaft. (Cripe 403 1, ¶ [0007].)
14. In the words of Cripe 403, “[t]he amplitude of any remaining
rotational signal is nominally inversely proportional to the number of
discrete magnetic field sensors used. It is recognized that the cost and
complexity of such a system increases with the number of magnetic field
sensors, whereas reliability is reduced.” (Cripe 403 1, ¶ [0007].)
15. In other words, conventional efforts to get a larger signal result in
higher costs, complexity, and lower reliability.
16. Cripe 403 seeks to provide “a single magnetic filed sensor that
surrounds the shaft without variation in sensitivity along its circumference,
and no sensitivity to interfering, isotropic magnetic fields.” (Cripe 403 1,
¶ [0008].)
17. Moreover, Cripes 403 seeks to provide “a magnetometer that can
measure the magnetic field surrounding a rotating shaft without the
requirement of multiple discrete sensors.” (Cripe 403 1, ¶ [00010].)
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18. Cripe 403 illustrates an embodiment of the rotatable shaft 26 and
coils 22, 24, in Figure 3, reproduced right.
19. Coils 22, 24 are wrapped around bobbin 70,
which is closely spaced to rotatable
shaft 26. (Cripe 403 4, ¶ [0045].)
20. A plurality of sense wires or
strips 28 of magnetically saturable
material are mounted on rotatable
shaft 26 parallel to the axis of
rotation 30. (Cripe 403 2, ¶ [0026];
4, ¶ [0046].)
21. Unlike the coil arrangement
in the torque sensor described by
Viola or the coil arrangement in the
torque sensor described in the
749 Specification, the coil
arrangement described in Cripe 403
does not comprise coaxial inner and
outer coils separated by a saturable
magnetic material.
{Cripe 403 Figure 3 is said to show part of a torque sensor}
C. Discussion
As the Appellant, Cripe bears the procedural burden of showing
harmful error in the Examiner’s rejections. See, e.g., In re Kahn, 441 F.3d
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977, 985-86 (Fed. Cir. 2006) (“On appeal to the Board, an applicant can
overcome a rejection [under § 103] by showing insufficient evidence of
prima facie obviousness”) (citation and internal quote omitted).
Our reviewing court has found “a proposed modification inappropriate
for an obviousness inquiry when the modification rendered the prior art
reference inoperable for its intended purpose.” In re Fritch, 972 F.2d 1260,
1265-66 n.12 (Fed. Cir. 1992), citing In re Gordon, 733 F.2d 900, 902 (Fed.
Cir. 1984).
In the present case, Viola teaches that the foil core element 44 is the
“active sensing component of the magnetic field sensing element.” (Viola 3,
¶ [0035].) As shown in Viola Figure 7, reproduced supra, foil 44 completely
encircles rotatable shaft 50, “thereby providing the circumferential angular
coverage desired of the sensing element.” (Id.) The Examiner has failed to
come forward with a rationale based on the prior art to substitute a
discontinuous plurality of saturable magnetic wires or strips, as taught by
Cripe 403 for the continuous foil element. The Examiner’s finding that the
wires taught by Cripe 403 “would encircle the shaft of Viola” (Ans. 8) is not
supported by credible evidence. Nowhere does Cripe 403 teach or suggest
that the saturable wires should encircle the rotatable shaft. Moreover,
Cripe 403 teaches that the wires or strips are bonded to rotatable shaft 26
parallel to the axis of rotation 30 of the shaft. (Cripe 403 3, ¶ [0026].) The
Examiner has not explained why such a teaching would have suggested that
a magnetically saturable foil, not in contact with the shaft, but positioned
between inner and outer concentric coils that surround the shaft, should be
replaced by wires or strips.
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Application 11/352,749

The Examiner’s finding that the magnetic saturable wires 28
described by Cripe 403 are functionally equivalent to magnetically saturable
foil 44 is particularly unconvincing in light of the torque sensor shown in
Figures 1-3. In this torque sensor, wires of magnetic saturable material form
the core element of oppositely wound coils. When these coils are positioned
closely together, Viola teaches that “effects of the inhomogeneities in the
magnetic field emanating from the shaft 12 can be substantially eliminated.”
(Viola 2, ¶ [0033].) Thus Viola recognized the use of wire cores as saturable
magnetic elements, but in a geometrical assembly quite different from the
one shown in the torque sensor of Figures 5-11.
The Examiner’s additional arguments against the patentability of other
claims do not cure the deficiencies of the principal argument. Accordingly,
we REVERSE all of the rejections of record.
D. Order
We REVERSE the rejection of claims 1-18 under 35 U.S.C. § 103(a)
in view of the combined teachings of Viola and Cripe 403.
REVERSED

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