Illinois Tool Works Inc.

Patent Trials and Appeals Board

Dec 21, 2020

2019006956 (P.T.A.B. Dec. 21, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
14/802,443 07/17/2015 Andrew J. Henry ITW 66070 1022
23721 7590 12/21/2020
GEORGE R. CORRIGAN
CORRIGAN LAW OFFICE
2168 COLLADAY POINT DRIVE
STOUGHTON, WI 53589
EXAMINER
ROSARIO-APONTE, ALBA T
ART UNIT PAPER NUMBER
3761
NOTIFICATION DATE DELIVERY MODE
12/21/2020 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
gcorrigan@new.rr.com
george.corrigan@corrigan.pro
kari.brekke@corrigan.pro
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte ANDREW J. HENRY

Appeal 2019-006956
Application 14/802,443
Technology Center 3700
____________

Before MICHAEL C. ASTORINO, BRUCE T. WIEDER, and
TARA L. HUTCHINGS, Administrative Patent Judges.

ASTORINO, Administrative Patent Judge.

DECISION ON APPEAL
Pursuant to 35 U.S.C. § 134(a), the Appellant1 appeals from the
Examiner’s decision to reject claims 1–13 under 35 U.S.C. § 103 as
unpatentable over Geissler2 and Liao3. We have jurisdiction under
35 U.S.C. § 6(b).
We REVERSE.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42. The Appellant identifies the real party in interest as
Illinois Tool Works Inc. Appeal Br. 3.
2 US 6,987,242 B2, issued Jan. 17, 2006.
3 US 2007/0075790 A1, published Apr. 5, 2007.
Appeal 2019-006956
Application 14/802,443

2

STATEMENT OF THE CASE
Subject Matter on Appeal
The Appellant’s invention “relates generally to the art of welding type
power supplies. More specifically, it relates to welding type power supplies
with pulse width modulated circuits.” Spec. ¶ 1.
Claims 1 and 8 are the independent claims on appeal. Claim 1,
reproduced below, is illustrative of the claimed subject matter.
1. A welding-type system comprising:
an input circuit disposed to receive input power and to
provide intermediate power;
a power circuit, having a power control input and at least
one switch responsive to the power control input, and wherein
the power circuit is disposed to receive intermediate power and
provide welding type output power;
a controller, having a set point input and a control output,
wherein the control output is connected to the power control
input, and wherein the control circuit includes a pwm module
responsive to the set point input and providing the control
output, wherein the pwm module includes a short duty cycle
linearizing module.

ANALYSIS
The Examiner rejects independent claims 1 and 8 based on the
combined teachings of Geissler and Liao. Final Act. 2–3, 4–5. The
Examiner finds Geissler teaches a welding-type system that includes
substantially all of the subject matter of claims 1 and 8, including a pulse
width modulation (“PWM”) module, except that Geissler fails to disclose
that the PWM module includes “a short duty cycle linearizing module.” Id.
at 2, 4–5. To remedy this deficiency, the Examiner finds:
Appeal 2019-006956
Application 14/802,443

3

Liao teaches a switching regulator system (Fig[s]. 7 and
8) comprising a clock oscillator system (600, 800) of a PWM
system, wherein the clock oscillator system includes a short
duty cycle linearizing module (amplifier circuit is capable of
short duty cycle linearization; p.0058; p.0031; claims 1, 11, 12,
16 and 17).
Id. at 3; see id. at 5. Thereafter, the Examiner determines that it would have
been obvious to one of ordinary skill in the art to have modified Geissler’s
PWM module with Liao’s teaching of a short duty cycle linearizing module
in order to have a stable welding arc. Id. at 3, 5.
The Appellant argues Liao fails to disclose “wherein the [PWM]
module includes a short duty cycle linearizing module,” as recited in
claims 1 and 8. See Appeal Br. 14; Reply Br. 2–3. The Appellant’s
argument is persuasive.
As pointed out by the Appellant, the Specification defines the term
“[s]hort duty cycle linearizing module . . . as ‘a module that is operable for
at least some shorter duty cycles [i.e., a duty cycle where the on time would
be less than the PWM minimum on time, without a frequency reduction (see
Spec. ¶¶ 42, 44),] and provides a [PWM] transfer function that is closer to
linear than the transfer function provided absent the short duty cycle
linearizing module.’”4 Appeal Br. 13–14 (quoting Spec. ¶ 47). In particular,
the Specification provides that for some welding applications, a PWM

4 The Specification defines the terms: “module” as “refer[ring] to software
and/or hardware that cooperates to perform one or more tasks, and can
include digital commands, control circuitry, power circuitry, networking
hardware, etc.” (Spec. ¶ 44); “PWM minimum on time” as “the time it takes
the switches being pulse width modulated to turn on and then off” (id. ¶ 10);
and “duty cycle” as “on time” and “the ratio of the time the switch is on
versus the total cycle time of the switching event” (id. ¶ 6).
Appeal 2019-006956
Application 14/802,443

4

control operating at the PWM minimum on time for a fixed frequency does
not provide a sufficiently low output. Spec. ¶¶ 10–11. Therefore, the
Specification discusses prior art approaches for reducing the minimum duty
cycle that are non-linearizing. A first type, “frequency reduction,” involves
increasing the total cycle time of the switching event (i.e., the period (T))
when operating the switch at a PWM minimum on time to allow for a
smaller duty cycle (i.e., ratio of the time the switch is on verses the total
cycle time of the switching event). See id. ¶¶ 12–14. A second type is to
skip pulses (“pulse skipping”). Id. ¶¶ 16 (“[Pulse skipping] produces a step
wise [PWM] transfer function and is not linear.”), 42 (“Pulse skipping does
not linearize the [PWM] transfer as linearizing the [PWM] transfer function
is used herein.”).
The Examiner finds that the claimed “short duty cycle linearizing
module” reads on Liao’s amplifier circuit. Ans. 9–10. The Examiner
supports this position by citing to Liao’s paragraph 58, which describes, with
added emphasis:
The invention circuit can also be modified to fix the
PWM switch-ON time while extending the duty cycle time. This
approach preferably achieves a fixed frequency (no cycle
skipping) very low duty cycle PWM operation to avoid similar
cycle-skipping audible noise––e.g., when cycles are skipped
and the voltage regulator does not turn ON such as in light
output load conditions.
We agree with Appellant that the phrase “fix the PWM switch-ON
time while extending the duty cycle time” is confusing because it uses the
term “duty cycle time,” which is generally understood as the time a PWM
switch is on (Spec. ¶ 6), to refer to the total cycle time or period of the PWM
operation (see id. ¶¶ 6, 8). See Reply Br. 2. By fixing the duty cycle for a
Appeal 2019-006956
Application 14/802,443

5

very low duty cycle PWM operation while extending the total cycle time,
Liao teaches frequency reduction, i.e., the prior art technique described in
the Specification that the claimed invention seeks to overcome. As
discussed above, the Specification describes frequency reduction (i.e.,
increasing the total cycle time or period of the PWM operation) as non-
linearizing. Spec. ¶¶ 12–14; Reply Br. 2. Therefore, we determine that the
Examiner’s finding that “short duty cycle linearizing module” reads on
Liao’s amplifier circuit is inadequately supported.
Thus, we do not sustain the Examiner’s rejection of independent
claims 1 and 8, and claims 2–7 and 9–13, which depend therefrom.

CONCLUSION
In summary:
Claims
Rejected
35 U.S.C. § References/Basis Affirmed Reversed
1–13 103 Geissler, Liao 1–13

REVERSED