Prosecution Insights
Last updated: April 19, 2026
Application No. 15/956,966

Welding Type Power Supply With Phase Shift Double Forward Converter

Final Rejection §103
Filed
Apr 19, 2018
Examiner
ROSARIO-APONTE, ALBA T
Art Unit
3761
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Illinois Tool Works Inc.
OA Round
5 (Final)
54%
Grant Probability
Moderate
6-7
OA Rounds
4y 1m
To Grant
81%
With Interview

Examiner Intelligence

Grants 54% of resolved cases
54%
Career Allow Rate
253 granted / 467 resolved
-15.8% vs TC avg
Strong +27% interview lift
Without
With
+27.0%
Interview Lift
resolved cases with interview
Typical timeline
4y 1m
Avg Prosecution
48 currently pending
Career history
515
Total Applications
across all art units

Statute-Specific Performance

§101
0.7%
-39.3% vs TC avg
§103
43.1%
+3.1% vs TC avg
§102
21.8%
-18.2% vs TC avg
§112
27.5%
-12.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 467 resolved cases

Office Action

§103
Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Drawings Figures 16-18 should be designated by a legend such as --Prior Art-- because only that which is old is illustrated (these figures were described in the specification page 1 for US8952293). See MPEP § 608.02(g). Corrected drawings in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. The replacement sheet(s) should be labeled “Replacement Sheet” in the page header (as per 37 CFR 1.84(c)) so as not to obstruct any portion of the drawing figures. If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance. Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claims 1-17, 21 and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Vogel (US 8,952,293). Regarding claim 1, Vogel teaches a method of providing welding type power comprising: receiving input power (from primary power supply 20; Col. 3, lines 54-56); pulse width modulating (abstract) a leading forward converter (24 or 26) having a first transformer (42) and a lagging forward converter (24 or 26; different from the leading forward converter) having a second transformer (62), such that the leading forward converter and the lagging forward converter operate as a pulse width modulated double forward converter to cooperatively provide a welding type output (abstract; title); phase shifting an output of the leading forward converter relative to an output of the lagging forward converter when at least one of a duty cycle, a current command and the welding type output exceeds a first threshold (abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27), wherein a leading edge (96, 124, 138, 150) of the leading forward converter is adjusted based on a time required for the second transformer to reset (abstract), and a trailing edge (98, 132, 140, 152) of the leading forward converter is adjusted relative to the leading edge to provide the phase shifting (abstract; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27); and operating the leading forward converter and the lagging forward converter in phase when at least one of the duty cycle, the current command and the welding type output is in a given range (Fig. 4, 6 and 7; Col. 4, lines 37-67; Col. 5, lines 1-3; Col. 5, lines 57-67; Col. 6, lines 1-48; Col. 8, lines 17-67; Col. 9, lines 1-27). Vogel fails to explicitly disclose phase shifting an output of the lagging forward converter relative to an output of the leading forward converter by adjusting the leading edge and trailing edge of the lagging forward converter. However, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified method of Vogel, by phase shifting the output of the lagging forward converter instead of the leading forward converter, since converter circuit 24 and 26 can be operated as either the leading or lagging converter circuit. POSITA would have known that phase shifting the output of the lagging forward converter instead of the leading forward converter would have a reasonable expectation of success and predictable results such as providing the proper welding output. Regarding claim 2, Vogel teaches the method as set forth above, further comprising phase shifting the output of the lagging forward converter relative to the output of the leading forward converter when at least one of the duty cycle, the current command, or the welding type output is less than a second threshold (abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27). Regarding claim 3, Vogel teaches the method as set forth above, further comprising phase shifting the output of the lagging forward converter relative to the output of the leading forward converter when at least one of the duty cycle, the current command, or the welding type output is less than a second threshold (abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27) and the welding type output is used for stick welding (Col. 3, lines 9-10). Regarding claim 4, Vogel teaches the method as set forth above, wherein phase shifting an output of the lagging forward converter relative to the output of the leading forward converter further comprises adjusting a trailing edge of the leading forward converter (abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27). Regarding claim 5, Vogel teaches the method as set forth above, wherein adjusting the trailing edge of the leading forward converter is done in response to a difference between an average current of the leading forward converter and an average current of the lagging forward converter (Col. 9, lines 61-67 and Col. 10, lines 1-17). Regarding claim 6, Vogel teaches the method as set forth above, further comprising phase shifting the output of the leading forward converter relative to the output of the lagging forward converter when at least one of the duty cycle, the current command, or the welding type output exceeds the first threshold, wherein a leading edge of the leading forward converter is adjusted and a trailing edge of the leading forward converter are adjusted to provide the phase shifting of the output of the leading forward converter, wherein phase shifting the output of the leading forward converter and phase shifting the output of the lagging forward converter are alternately performed (abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27). Regarding claim 7, Vogel teaches the method as set forth above, wherein phase shifting the output of the lagging forward converter provides sufficient time for the transformer core to reset (abstract). Regarding claim 8, Vogel teaches the method as set forth above, wherein the phase shifting the output of the lagging forward converter is responsive to an output load current (Col. 8, lines 17-37; Col. 9, lines 61-67 and Col. 10, lines 1-17). Regarding claim 9, Vogel teaches the method as set forth above, wherein phase shifting the output of the lagging forward converter responsive to the output load current is performed such that at least one of a control without discontinuities and a linear control is provided (Col. 8, lines 17-37; Col. 9, lines 61-67 and Col. 10, lines 1-17). Regarding claim 10, Vogel teaches the method as set forth above, wherein the pulse width modulating includes adjusting the duty cycle by an offset that is a function of at least one of the duty cycle, the current command and the welding type output (abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27). Regarding claim 11, Vogel teaches the method as set forth above, wherein the function of at least one of the duty cycle, the current command and the welding type output is at least one of: a multiple of the duty cycle; a multiple of the current command; a multiple of the welding type output; a value in a look up table; responsive to a time limit; responsive to a selected weld process; and responsive to a state of the welding arc (abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27). Regarding claim 12, Vogel teaches the method as set forth above, wherein the phase shifting an output of the lagging forward converter further comprises adjusting the first threshold in response to at least one of the duty cycle, the current command and the welding type output, wherein when at least one of the duty cycle, the current command and the welding type output exceeds the adjusted first threshold the phase shifting an output of the lagging forward converter is performed (the dynamic voltage/current requirements change, therefore the threshold is adjusted; abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27). Regarding claim 13, Vogel teaches the method as set forth above, wherein the adjusted first threshold is adjusted between at least one of: two discreet values; more than two discreet values; or a range of values (the dynamic voltage/current requirements change, therefore the threshold is adjusted; abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-2). Regarding claim 14, Vogel teaches the method as set forth above, wherein the first threshold is adjusted based on whether the leading forward converter and the lagging forward converter are in phase or out of phase (the dynamic voltage/current requirements change, therefore the threshold is adjusted; abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-2). Regarding claim 15, Vogel teaches the method as set forth above, wherein adjusting the first threshold increases the duty cycle to more than 50% for at least one of the leading forward converter or the lagging forward converter (Col. 5, lines 28-56). Regarding claim 16, Vogel teaches the method as set forth above, further comprising disabling the leading forward converter and enabling the lagging forward converter when at least one of the duty cycle, the current command and the welding type output is less than a second threshold (abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27) and the welding type output is used for stick welding (Col. 3, lines 9-10). Regarding claim 17, Vogel teaches the method as set forth above, further comprising alternately disabling the leading forward converter and enabling the lagging forward converter, and then enabling the leading forward converter and disabling the lagging forward converter, when at least one of the duty cycle, the current command and the welding type output is less than a second threshold, and in response to sensing a first bus voltage and sensing a second bus voltage (abstract; title; Fig. 5 and 8-10; Col. 5, lines 4-56; Col. 6, lines 49-67; Col. 7, lines 1-67; Col. 8, lines 1-67; Col. 9, lines 1-27) and the welding type output is used for stick welding (Col. 3, lines 9-10). Regarding claim 21, Vogel teaches the method as set forth above, wherein adjusting the first threshold increases the duty cycle to more than 50% before phase shifting is performed (Col. 5, lines 28-56). Regarding claim 22, Vogel teaches the method as set forth above, further comprising resetting the leading and lagging transformers every cycle without skipping a pulse (Col. 5, lines 28-56). Response to Arguments Drawings objections Examiner is persuaded by the arguments regarding Figure 4 (remarks page 7, lines 10-11. However, Examiner found the arguments regarding Figures 16-18 not persuasive, since Figure 16 is the same as Figure 1 of prior art US 8,952,296, Figure 17 is the same as Figure 2 of prior art US 8,952,296, and Figure 18 is the same as Figure 3 of prior art US 8,952,296. 112 rejections The 112b rejection on claim 13 is hereby withdrawn in view of the claims amendments filed on 02/23/2026. 103 rejections Applicant's arguments filed 02/23/2026 have been fully considered but they are not persuasive. Regarding the drawings, Applicant argues that “The disclosure of Vogel does not provide any motivation to a person of ordinary skill in the art to phase shift an output of the lagging forward converter relative to an output of the leading forward converter when at least one of a duty cycle, a current command and the welding type output exceeds a first threshold, wherein a leading edge of the lagging forward converter is adjusted based on a time required for the second transformer to reset, and a trailing edge of the lagging forward converter is adjusted relative to the leading edge to provide the phase shifting. In contrast, the present specification details multiple undesirable effects of the Vogel system. See e.g., Specification, 11 [0007], [0008]. There is no evidence presented that a person of ordinary skill in the art would understand these undesirable effects or how to overcome them by phase shifting the lagging forward converter relative to the leading forward converter.” on remarks page 8, lines 32-33, and page 9, lines 1-8. In response to Applicant’s arguments, Vogel fails to explicitly disclose phase shifting an output of the lagging forward converter relative to an output of the leading forward converter by adjusting the leading edge and trailing edge of the lagging forward converter. However, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified method of Vogel, by phase shifting the output of the lagging forward converter instead of the leading forward converter, since converter circuit 24 and 26 can be operated as either the leading or lagging converter circuit. POSITA would have known that phase shifting the output of the lagging forward converter instead of the leading forward converter would have a reasonable expectation of success and predictable results such as providing the proper welding output. For these reasons, the arguments are not persuasive. Regarding claims 2-17, 21 and 22, Applicant relies on the same arguments, therefore, the same response applies. Conclusion THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALBA T ROSARIO-APONTE whose telephone number is (571)272-9325. The examiner can normally be reached M to F; 8am-5pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Steven Crabb can be reached at 571-270-5095. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ALBA T ROSARIO-APONTE/Examiner, Art Unit 3761 03/19/2026 /STEVEN W CRABB/Supervisory Patent Examiner, Art Unit 3761
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Prosecution Timeline

Apr 19, 2018
Application Filed
Feb 10, 2021
Non-Final Rejection — §103
Aug 19, 2021
Response Filed
Nov 09, 2021
Final Rejection — §103
Apr 18, 2022
Request for Continued Examination
Apr 24, 2022
Response after Non-Final Action
May 09, 2022
Final Rejection — §103
Oct 13, 2022
Notice of Allowance
Oct 18, 2022
Applicant Interview (Telephonic)
Oct 18, 2022
Examiner Interview Summary
Jan 13, 2023
Response after Non-Final Action
Jan 13, 2023
Response after Non-Final Action
Nov 09, 2023
Response after Non-Final Action
Nov 15, 2023
Response after Non-Final Action
Dec 13, 2023
Response after Non-Final Action
Dec 13, 2023
Response after Non-Final Action
Dec 13, 2023
Response after Non-Final Action
Mar 19, 2024
Response after Non-Final Action
Mar 22, 2024
Response after Non-Final Action
Apr 22, 2024
Response after Non-Final Action
Apr 22, 2024
Response after Non-Final Action
Apr 29, 2024
Response after Non-Final Action
Jun 04, 2024
Response after Non-Final Action
Jul 03, 2024
Response after Non-Final Action
Jun 18, 2025
Response after Non-Final Action
Sep 15, 2025
Non-Final Rejection — §103
Feb 23, 2026
Response Filed
Mar 19, 2026
Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

6-7
Expected OA Rounds
54%
Grant Probability
81%
With Interview (+27.0%)
4y 1m
Median Time to Grant
High
PTA Risk
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