Prosecution Insights
Last updated: April 19, 2026
Application No. 17/767,704

Rotary Transformer

Final Rejection §103§112
Filed
Apr 08, 2022
Examiner
LIAN, MANG TIN BIK
Art Unit
2837
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Digital Motor Holdings LLC
OA Round
2 (Final)
70%
Grant Probability
Favorable
3-4
OA Rounds
2y 10m
To Grant
97%
With Interview

Examiner Intelligence

Grants 70% — above average
70%
Career Allow Rate
921 granted / 1312 resolved
+2.2% vs TC avg
Strong +26% interview lift
Without
With
+26.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
82 currently pending
Career history
1394
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
53.4%
+13.4% vs TC avg
§102
23.5%
-16.5% vs TC avg
§112
20.8%
-19.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1312 resolved cases

Office Action

§103 §112
DETAILED ACTION 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 . Response to Arguments Applicant’s arguments with respect to claims 6-14 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Drawings The drawings received on 11/12/2025 are acceptable. Claim Objections Claims 6 and 7 are objected to because of the following informalities: Regarding claim 6, applicant should review whether or not the indentations of the claimed limitations are as intended. For example, the each of “a rotating…,” “a stationary element…,” “a radial gap…” and “wherein” clauses has double tab indentation, but each of “providing…” and “placing…” limitations of the last two clauses has only a single tab indentation. Also, “providing a rotary transformer comprising,” of the original claimed limitation is neither crossed nor present in amended claim 6. Claim 7 is objected as being dependent on claim 6. Appropriate correction is required. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 6, 7, 13 and 14 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claim 6 recites the limitation "the outer diameter" in line 10. There is insufficient antecedent basis for this limitation in the claim. Claim 6 also recites the limitation "the outer diameter" in line 10. There is insufficient antecedent basis for this limitation in the claim. It’s further not clear what’s intended by “the diameter of the outer diameter of the cylinder” in line 10. For examination purpose the limitation in question is interpreted as the diameter of the hole is greater than the diameter of the disc. Claim 6 recites the limitation "the inner diameter the hole" in line 10. There is insufficient antecedent basis for this limitation in the claim. For examination purpose, the limitation in question is interpreted as the diameter of the hole. Claim 6 recites the limitation "the distance" in lines 14 and 15, respectively. There is insufficient antecedent basis for this limitation in the claim. Claim 6 recites the limitation "the outer diameter" in line 16. There is insufficient antecedent basis for this limitation in the claim. Similar clarifications need to be made in claim 13. Claim 14 is rejected as being dependent on claim 13. These 112(b) rejections above are mere examples. Applicant needs to review the claim set in its entirely to conform with 35 USC 112(b) to help expedite the prosecution. 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. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claims 6, 13 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Gilibert et al. (U.S. PG. Pub. No. 2020/0198104 A1) in view of Gao et al. (U.S. PG. Pub. No. 2016/0094114 A1). With respect to claim 6, best understood in view of 35 USC 112(b) rejection, Gilibert et al., hereinafter referred to as “Gilibert,” teaches a method of using a rotary transformer (Figs. 1-3, rotary transformer is shown in Fig. 3) comprising the steps of, a rotating element 13 comprising a secondary winding 10 and a core 14 comprising a cylinder 14a (annotated Fig. 3) having a diameter d1 and attached to a disc 14b having a diameter d2, and made with a material able to be machined and having magnetic properties the same as soft magnetic ferrite; a stationary element 11 comprising a primary winding 10 and a core 15 comprising a round cup (core 15 has cup shape) having an inner diameter d3 greater than the diameter of the disc of the rotating core and a hole (space occupied by the left end of the cylinder 14a) in the center having a diameter d4 greater than the diameter of the outer diameter of the cylinder, and made with the material able to be machined and having magnetic properties the same as soft magnetic ferrite: and a radial gap g1 and g2 comprising two locations (locations at g1 and g2) with a length (gap width of g1 and g2) that is half of the sum of (a) the distance between the inner diameter of the cup of the stationary element core and the diameter of the disc of the rotating element core and (b) the distance between the inner diameter of the hole of the stationary element core and the outer diameter of the cylinder of the rotating element core, wherein the rotary transformer is configured to operate at a frequency of at least 50 kHz; providing a wound field synchronous machine (“synchronous electrical motor” para. [0009]) comprising a rotor winding 9 (paras. [0009], [0046], [0051], [0054], [0065] and [0067]). PNG media_image1.png 451 543 media_image1.png Greyscale providing a wound field synchronous machine comprising bearing even though a person with ordinary skill in the art knows there would be a bearing; and placing the rotary transformer between the rotor winding and the bearing of the wound field synchronous machine. Gilibert does not expressly teach providing wound field synchronous machine comprising a bearing even though a person with ordinary skill in the art knows there would be a bearing; and placing the rotary transformer between the rotor winding and the bearing of the wound field synchronous machine. Gao et al., hereinafter referred to as “Gao,” teaches a method of using a rotary transformer comprising the steps of, providing a wound field synchronous machine 100 comprising a rotor winding 135 and a bearing 160B; and placing the rotary transformer between the rotor winding and the bearing of the wound field synchronous machine (paras. [0011], [0024] and [0027]). It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to have the rotary transformer between the rotor winding and the bearing of the wound field synchronous machine as taught by Gao to the rotary transformer of Gilibert to allow smooth rotation of the shaft, thereby improving efficiency of transferring loads and prevent wear and tear. With respect to claim 13, best understood in view of 35 USC 112(b) rejection, Gilibert teaches a method of using a rotary transformer (Figs. 1-3, rotary transformer is shown in Fig. 3) comprising the steps of, providing a rotary transformer (Fig. 3) comprising, a rotating element 13 comprising a secondary winding 10 and a core 14 comprising a cylinder 14a (annotated Fig. 3) having a diameter d1 and attached to a disc 14b having a diameter d2, and made with a material able to be machined and comprising a soft magnetic composite of iron particles coated with an electrically resistive coating; and a stationary element 11 comprising a primary winding 10 and a core 15 comprising a round cup (core 15 has cup shape) having an inner diameter d3 greater than the diameter of the disc of the rotating core and a hole (space occupied by the left end of the cylinder 14a) in the center having a diameter d4 greater than the diameter of the outer diameter of the cylinder, and made with the material able to be machined and comprising a soft magnetic composite of iron particles coated with an electrically resistive coating; and a radial gap g1 and g2 comprising two locations (locations of g1 and g2) with a length (gap width of g1 and g2) that is half of the sum of (a) the distance between the inner diameter of the cup of the stationary element core and the diameter of the disc of the rotating element core and (b) the distance between the inner diameter of the hole of the stationary element core and the outer diameter of the cylinder of the rotating element core, wherein the rotary transformer is configured to operate at a frequency of at least 50 kHz; providing a wound field synchronous machine (“synchronous electrical motor” para. [0009]) comprising a rotor winding 9 (paras. [0009], [0046], [0051], [0054], [0055], [0065] and [0067]). Gilibert does not expressly teach providing wound field synchronous machine comprising a bearing even though a person with ordinary skill in the art knows there would be a bearing; and placing the rotary transformer between the rotor winding and the bearing of the wound field synchronous machine. Gao teaches a method of using a rotary transformer comprising the steps of, providing a wound field synchronous machine 100 comprising a rotor winding 135 and a bearing 160B; and placing the rotary transformer between the rotor winding and the bearing of the wound field synchronous machine (paras. [0011], [0024] and [0027]). It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to have the rotary transformer between the rotor winding and the bearing of the wound field synchronous machine as taught by Gao to the rotary transformer of Gilibert to allow smooth rotation of the shaft, thereby improving efficiency of transferring loads and prevent wear and tear. With respect to claim 14, Gilibert in view of Gao teaches a method of using a rotary transformer of claim 13 wherein comprising the soft magnetic composite of iron particles coated with an electrically resistive coating also means having magnetic properties the same as soft magnetic ferrite (Gilibert, para. [0065]). Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Gilibert in view of Gao, as applied to claim 6 above, and further in view of Box (U.S. Patent No. 9,525,376 B2). With respect to claim 7, Gilibert in view of Gao teaches a method of using a rotary transformer of claim 6 further comprising the steps of providing all additional physical elements of a resonant field exciter 125 (Gao) comprising, at least one AC voltage generator having a voltage and driving frequency (Gao, paras. [0016] and [0019]); at least one resonant field exciter in communication with AC generator, the resonant field exciter having a rotary reference frame, the resonant field exciter is configured to operate in a resonant mode at a resonant frequency of at least 50 kHz; a controller device 170 in communication with the AC generator and the resonant field exciter and configured to measure the voltage and current into the resonant field exciter, track the resonance frequency, and adjust the driving frequency to substantially match the resonance frequency to maximize AC current transfer; and a rectifier 145 in communication with the resonant field exciter and configured to convert the AC current to DC current before it goes into a rotor winding of a wound field synchronous machine; and placing the additional elements in communication with the rotary transformer to form a resonant field exciter configured to reside within and communicate with the wound field synchronous machine (Gao, paras. [0015]-[0016], [0019]-[0020]). Gao does not expressly teach at least one square wave, and a static reference frame and a resonant circuit comprising in series a resonant capacitor and the rotary transformer of the invention with a variable leakage inductance Box teaches a method of using a rotary transformer, comprising: at least one square wave, and a static reference frame and a resonant circuit comprising in series a resonant capacitor and the rotary transformer of the invention with a variable leakage inductance (claims 1 and 15). It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to have the square wave as taught by Box to the method of using a rotary transformer of Gilibert in view of Gao to provide the desired transitions between high and low states to meet design requirements. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 MANGTIN LIAN whose telephone number is (571)270-5729. The examiner can normally be reached Monday-Friday 0800-1700. 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, Shawki S. Ismail can be reached at 571-272-3985. 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. /MANG TIN BIK LIAN/ Primary Examiner, Art Unit 2837
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Prosecution Timeline

Apr 08, 2022
Application Filed
Jul 07, 2025
Non-Final Rejection — §103, §112
Oct 06, 2025
Response Filed
Dec 30, 2025
Final Rejection — §103, §112 (current)

Precedent Cases

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

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Prosecution Projections

3-4
Expected OA Rounds
70%
Grant Probability
97%
With Interview (+26.4%)
2y 10m
Median Time to Grant
Moderate
PTA Risk
Based on 1312 resolved cases by this examiner. Grant probability derived from career allow rate.

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