Ex Parte Heydt et al

Board of Patent Appeals and Interferences

Jul 28, 2008

11014348 (B.P.A.I. Jul. 28, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
_____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________

Ex parte JEFFREY A. HEYDT,
JAMES W. DuLANEY JR., DAVID R. STREET,
NICHOLAS SWEZEY, and STUART KEVIN FRANCIS
_____________

Appeal 2008-2264
Application 11/014,348
Technology Center 2800
______________

Decided: July 28, 2008
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Before KENNETH W. HAIRSTON, ROBERT E. NAPPI,
and KARL D. EASTHOM, Administrative Patent Judges.

NAPPI, Administrative Patent Judge.

DECISION ON APPEAL

This is a decision on appeal under 35 U.S.C. § 134 of the rejection of
claims 1 through 6, 8, 10 through 16, and 19.
We reverse the Examiner’s rejections of these claims.

Appeal 2008-2264
Application 11/014,348

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INVENTION

The invention is directed to method of controlling a brushless dc
motor by applying a series of drive pulses from a first commutation state.
Each pulse is terminated when a maximum current is reached and re-applied
when the current decays. The change in commutation state of the motor is
determined in relation to the change in elapsed times between successive
pulses. See pages 2, 8, 9, and figure 71 of Appellants’ Specification. Claim
1 is representative of the invention and is reproduced below:
1. A method comprising applying a sequence of drive pulses to rotate
a brushless dc motor, wherein the sequence of drive pulses is switched
from a first commutation state to a second commutation state of the
motor at a time determined in relation to changes in elapsed time
between successive pulses in said sequence.

REFERENCE

Heydt US 6,577,088 B2 Jun. 10, 2003

REJECTION AT ISSUE
Claims 1 through 6, 8, 10 through 16, and 19 stand rejected under 35
U.S.C. § 102(b) as being anticipated by Heydt.2 The Examiner’s rejection is
on pages 3 through 4 of the Answer.

1 Appellants’ representatives admitted in the hearing of July, 17, 2008 that
figure 7 was poorly drafted and that not all of the traces (e.g. traces 226, 228,
230) clearly depict the change elapsed time interval. The Appellants are
encouraged to correct the drawing.
2 Appellants incorrectly list claims 1-5, 7, 8, and 10-16 as rejected in their
Brief on page 6, matching the incorrect listing on Form-326 of the
Examiner’s Office Action , mailed Feb. 24, 2006. We also note that the
Appeal 2008-2264
Application 11/014,348

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Throughout the opinion, we make reference to the Brief (received
January 16, 2007), Reply Brief (received July 25, 2007) and the Answer
(mailed May 25, 2007) for the respective details thereof.

ANALYSIS
Appellants contend, on pages 7 through 11 of the Brief, that the
Examiner’s rejection of claims 1 through 6, 8, 10 through 16, and 19 is in
error. Appellants reason that the rejection of each of independent claims 1,
11, and 19 is in error, as the claims recite “contemplate switching
commutation states at a time determined in relation to changes in elapsed
time between successive pulses.” Br. 7 (emphasis original). Appellants
assert that Heydt teaches determining when to switch commutation states by
application of sense pulses to the non-commutated states to determine motor
position. Br. 9.
The Examiner responds stating:
Heydt et al. show control of sequence and duration of the operation of
the switching transistors based on comparator 148 pulsating signal
outputs. In controller 134 a timer 217 initiates a pulse at a time t0
when voltage threshold level is reached. At that time comparator 148
outputs Is pulse 220, (shown in Fig. 5). The receipt of the Is pulse will
cause the controller 134 to stop the timer (time t1) and report the
elapsed time between t0 and t1 and instruct the spindle driver circuitry
136 to cease further application of the drive pulse, wherein switches
AH and BL 150, 156 are turned off. That represents claimed
switching from a first commutation state to a second commutation
state and time elapsed between successive pulses in the sequence.
Ans. 5.

Examiner identified that claim 8 is dependent upon allowable claim 7 and as
such the Examiner’s indication that claim 8 is rejected appears to be in error.
Appeal 2008-2264
Application 11/014,348

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Appellants’ arguments have convinced us of error in the Examiner’s
rejection of claims 1 through 6, 8, 10 through 16, and 19. Independent claim
1 recites “wherein the sequence of drive pulses is switched from a first
commutation state to a second commutation state of the motor at a time
determined in relation to changes in elapsed time between successive pulses
in said sequence.” Independent claims 11 and 19 recite similar limitations.
Thus, the scope of the independent claims includes that the commutation
state of the sequence of drive pulses is changed based upon a determination
in relation to the changes in time between successive commutation pulses.
We disagree with the Examiner’s rationale that Heydt’s teaching,
shown in figure 6 of measuring the rise time of voltage for the pulse Is,
shown as item 220, represents an elapsed time between pulses as claimed.
As discussed above the claims recite that the commutation is in relation to
the elapsed time between drive pulses. Heydt’s pulse, Is and the voltage it
creates Vm are part of a sense pulse. (Heydt, col. 7, ll. 16-20). Heydt
specifically teaches that the sense pulses are not of sufficient power to drive
the motor. (Heydt, col. 7, ll. 21-27). These sense pulses are used to
determine the motor position, which is consequently used to determine
commutation of the motor. (Heydt, col. 7, ll. 28-56). Thus, we do not find
that Heydt teaches that the commutation is determined in relation to the time
between drive pulses. Accordingly, we do not find that Heydt discloses all
of the limitations of the independent claims and we will not sustain the
Examiner’s rejection of claims 1 through 6, 8, 10 through 16, and 19.

Appeal 2008-2264
Application 11/014,348

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ORDER
The decision of the Examiner is reversed.

REVERSED

KIS

David K. Lucente
Seagate Technology L.L.C.
Intellectual Property - COL2LGL
389 Disc Drive
Longmont, CO 80503