Ex parte Eland et al.

Board of Patent Appeals and Interferences

Aug 28, 2000

08603696 (B.P.A.I. Aug. 28, 2000)

1
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(2) is not binding precedent of the Board.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. 25
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte MICHAEL P. ELAND and KEVIN L. MILLER
_____________
Appeal No. 1998-2498
Application No. 08/603,696
______________
ON BRIEF
_______________
Before KRASS, JERRY SMITH and BARRY, Administrative Patent Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of claims 1-12, all of the
pending claims.
The invention is directed to position sensors. In order to improve on prior art
systems, wherein the position of a magnetic reading head is determined by accurately
determining a switch trip position, but wherein the trigger position of the switch varied from
drive to drive due to component and assembly tolerances, the instant invention accurately
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determines once during manufacture the switching position and records that position in a
permanent memory. Since the switching position is known to the drive controller,
calibration of transducer position during an initialization procedure is easily enabled. Thus,
accurate transducer position is achieved without requiring absolute position accuracy of a
sensor switching point.
Representative independent claim 5 is reproduced as follows:
5. A method for calibrating a position sensor for an object, the method
comprising the following steps:
a. moving the object with a controller;
b. sensing when the sensor switches from a first state to a second
state, the position of the sensor relative to a reference position being
unknown;
c. measuring the position of the object relative to the reference
position with a precision calibration fixture when the sensor switches from
the first state to the second state; and
d. recording the position of the object in a memory device readable
by the controller, thereby enabling the position of the object relative to the
reference position to be accurately known.
The examiner relies on the following references:
Alsborg et al. (Alsborg) 5,491,595 Feb. 13, 1996
(Filed Sep. 09, 1992)
Fornoff et al. (Fornoff) GB 2,265,719 Oct. 06, 1993
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Claims 1-12 stand rejected under 35 U.S.C. § 103 as unpatentable over Alsborg in
view of Fornoff.
Reference is made to the briefs and answer for the respective positions of
appellants and the examiner.
OPINION
We reverse.
It is the examiner’s position that Alsborg discloses the claimed invention but for the
claimed memory for storing a numerical value indicative of the position of the object at a
reference position relative to a sensor. The examiner relies on Fornoff for the teaching of
storing a numerical value indicative of the position of the object at a reference position
relative to a sensor for the purpose of accurately determining the distance from the sensor
when switching occurs. The examiner then concludes that it would have been obvious to
use a memory to store a numerical value indicative of the position of the object at a
reference position relative to a sensor as taught by Fornoff on the system of Alsborg in
order to accurately determine the distance from the sensor when switching occurs.
Fornoff does, indeed, determine the reference position of an object and it does so
by sensing switching points as a magnetic element is passed back and forth over a
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Application No. 08/603,696
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Hall element, storing the switching points and determining the reference position by
averaging measured distance, while another Hall element measures the number of
revolutions of a drive motor in order to determine relative movement of the object about the
reference position. However, each of independent claims 1 and 9 requires the stored
numerical value, which is indicative of a position of the object relative to a reference
position when the sensor switches from a first to a second state, to have been previously
determined. Independent claim 5 recites the actual calibration wherein the position of the
object relative to the reference position is measured with a precision calibration fixture
when the sensor switches from the first to the second state and then the position is
recorded in a memory device, readable by the controller and enabling the position of the
object relative to the reference position to be accurately known.
While Fornoff counts rotations of the drive motor and this numerical value does
indicate location of the object relative to whatever was the counting starting point, when the
sensor switches, we find ourselves in agreement with appellants that these rotation counts
of Fornoff are not measurements of the object position relative to the reference position
“because the reference position is not known” [principal brief, page 9]. There simply is no
predetermined numerical value, indicative of an object position relative to a reference
position, as set forth in claims 1 and 9, in Fornoff. Similarly, Fornoff lacks any suggestion
of the calibration method set forth in instant claim 5 wherein the
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position of the object relative to the reference position is measured with a precision
calibration fixture when the sensor switches from the first to the second state and then the
position is recorded in a memory device. The relative position is not measured or
recorded by Fornoff because the reference position is simply not known at the time the
sensor switches states. While the relative position may be known after the fact, Fornoff
does not provide for the claimed numerical value “having been previously accurately
determined.” Alsborg does not remedy this deficiency of Fornoff.
Accordingly, the examiner’s decision rejecting claims 1-12 under 35 U.S.C.
§ 103 is reversed.
REVERSED
ERROL A. KRASS )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
JERRY SMITH ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
LANCE LEONARD BARRY )
Administrative Patent Judge )
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eak/vsh
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