Prosecution Insights
Last updated: April 19, 2026
Application No. 18/706,742

Magnetic Core

Non-Final OA §102§103§112
Filed
May 01, 2024
Examiner
HAWKINS, DOMINIC E
Art Unit
2858
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Enoda Ltd.
OA Round
1 (Non-Final)
87%
Grant Probability
Favorable
1-2
OA Rounds
2y 4m
To Grant
99%
With Interview

Examiner Intelligence

Grants 87% — above average
87%
Career Allow Rate
625 granted / 720 resolved
+18.8% vs TC avg
Moderate +12% lift
Without
With
+12.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 4m
Avg Prosecution
28 currently pending
Career history
748
Total Applications
across all art units

Statute-Specific Performance

§101
1.5%
-38.5% vs TC avg
§103
59.2%
+19.2% vs TC avg
§102
25.4%
-14.6% vs TC avg
§112
10.6%
-29.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 720 resolved cases

Office Action

§102 §103 §112
Detailed Action The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claims 1, 2, 5, 7-11, 14, and 16-26 of U.S. Application 18/706,742 filed on December 18, 2024 are presented for examination. Priority Receipt is acknowledged of certified copies of papers submitted under 35 U.S.C. 119(a)-(d), which papers have been placed of record in the file. Claim Objections Claims 8 and 24-26 are objected to because of the following informalities: Please amend the claim phrases “each is limb” to “each limb is”. 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 10 ,11, 14, and 16-26 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. Regarding claim 10, the phrase “wherein: each limb comprises a first group of strips, a second group of strips, and a third group of strips, wherein the first group of strips is arranged between the second group of strips and the third group of strips;” is indefinite for the reason below. The Examiner cannot interpret if the term includes the forming the three sets of strips are the same as the group of strips or another group of strips. The Examiner will interpret the phrase being the same set of strips. Appropriate correction is required. Claims 11, 14, and 16-26 are also rejected as they depend on claim 10. Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. Claims 1, 2, 5, 7-9, and 22-26 are rejected under 35 U.S.C. 102(a1) as being unpatentable over Wallumrod et al (EP2814045). PNG media_image1.png 593 368 media_image1.png Greyscale Prior Art: Wallumrod Regarding claim 1, Wallumrod discloses a magnetic core (10) suitable for an electromagnetic device (shown in figs 1-25), the core comprising; three arc-shaped (par 11 discloses C shaped) limbs (50, 51, and 52) wherein the each limbs are arranged around a central axis (A), and each limb has a first end (31) and a second end (30), wherein the first ends of the limbs are mutually connected at a first position (41) along the central axis, and the second end of the limbs are mutually connected at a second position (40) along the central axis, and wherein each limb comprises a plurality of bent electrical steel strips (par 11 discloses laminated sheets of ferromagnetic material and par 41 discloses steel) ; wherein each one of the plurality of bent electrical steel strips comprises a first group of strips (35), a second group of strips (21), and a third group of strips (31), (shown in fig 14) wherein the first group of strips is arranged between the second group of strips and the third group of strips (shown in fig 14); wherein the first group of strips has a first thickness, the second group of strips has a second thickness, the third group of strips has a third thickness (shown in fig 14 where the sections have different thickness), and the first thickness is greater than both the second thickness and the third thickness (as shown in fig 14 as being thicker as shown); and wherein the first group of strips has a first width, the second group of strips has a second width, the third group of strips has a third width, and the first width is greater than both the second width and the third width (shown in figs 11-14 as the first group is greater than both the second and third group). Regarding claim 2, Wallumrod discloses wherein each the limbs are arranged equally- spaced around the central axis (as shown in figs 1-15 as equally spaced). Regarding claim 5, Wallumrod discloses wherein the second thickness is equal to the third thickness (shown in figs 1-15 as being the same thickness as shown). Regarding claim 7, Wallumrod discloses wherein the second width is equal to the third width (shown in figs 1-15 as being the same width as shown). Regarding claim 8, Wallumrod discloses wherein each is limb arranged to receive a respective primary winding and a respective secondary winding (par 52 discloses having LV and HV windings). Regarding claim 9, Wallumrod discloses an electromagnetic device comprising: the core of any of claim 1; a respective primary winding arranged around each limb; and a respective secondary winding arranged around each limb (par 51 discloses LV and HV 60-62 are arranged on each limb). Regarding claim 22, Wallumrod discloses wherein the second thickness is equal to the third thickness (shown in figs 1-15 as being the same thickness as shown). Regarding claim 23, Wallumrod discloses wherein the second width is equal to the third width (shown in figs 1-15 as being the same width as shown). Regarding claim 24, Wallumrod discloses wherein each is limb arranged to receive a respective primary winding and a respective secondary winding (par 52 discloses having LV and HV windings). Regarding claim 25, Wallumrod discloses wherein each is limb arranged to receive a respective primary winding and a respective secondary winding (par 52 discloses having LV and HV windings). Regarding claim 26, Wallumrod discloses wherein each is limb arranged to receive a respective primary winding and a respective secondary winding (par 52 discloses having LV and HV windings). 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 of this title, 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. In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. Claims 10, 11, 14, 16-18, 20, and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Wallumrod et al (EP2814045) in view of Vollrath et al (USPGPub 20110109412). Regarding claim 10, Wallumrod discloses a method of manufacturing a magnetic core (10) suitable for an electromagnetic device (shown in figs 1-25), the method comprising: forming three sets of strips (35, 21, and 31) from one or more sheets of electrical steel(par 11 discloses laminated sheets of ferromagnetic material and par 41 discloses steel), wherein each set of strips comprises a plurality of strips, and arranging each of the three sets of strips into a respective stack (shown in figs 10-14) ;bending each stack into an arc-shaped limb (par 11 discloses C shaped), each limb having a first end (31) and a second end (30), wherein: each limb comprises a first group of strips (35), a second group of strips (21), and a third group of strips (31), wherein the first group of strips is arranged between the second group of strips and the third group of strips (shown in fig 14);the first group of strips has a first thickness, the second group of strips has a second thickness, the third group of strips has a third thickness (shown in fig 14 where the sections have different thickness), and the first thickness is greater than both the second thickness and the third thickness (as shown in fig 14 as being thicker as shown); and the first group of strips has a first width, the second group of strips has a second width, the third group of strips has a third width, and the first width is greater than both the second width and the third width (shown in figs 11-14 as the first group is greater than both the second and third group).;positioning each limb around a central axis (A);mutually connecting the first ends of the limbs at a first position (41) along the central axis; and mutually connecting the second ends (30) of the limbs at a second position along the central axis (shown in figs 1-15 as connecting at multiple points).Wallumrod does not fully disclose the one or more sheets of electrical steel comprise an insulating surface layer. However, Vollrath discloses the one or more sheets of electrical steel comprise an insulating surface layer (par 43 discloses the core is coated with a resin). It would have been obvious to one of ordinary skill in art before the effective filing date of the claimed invention to combine Wallumrod in view of Vollrath in order to properly hold the core together without electrical interference. Regarding claim 11, Wallumrod discloses between the steps of bending each stack into an arc-shaped limb and mutually connecting the second ends of the limbs at the second position along the central axis (par 11 discloses producing C-shaped frame section), for each limb: applying a primary winding around the limb; and applying a secondary winding around the limb (par 51 discloses LV and HV 60-62 are arranged on each limb). Regarding claim 14, Wallumrod discloses wherein the second thickness is equal to the third thickness (as shown in figs 10-15 as the thickness are even). Regarding claim 16, Wallumrod discloses wherein the second width is equal to the third width (as shown in figs 10-15 as the widths are even). Regarding claim 17, Wallumrod discloses between the steps of bending each stack into an arc-shaped limb and mutually connecting the first ends of the limbs at a first position along the central axis, for each limb: machining the first end to form a first edge for alignment with the central axis at the first position, the first edge having an inclusive angle of 120 degrees; and machining the second end to form a second edge for alignment with the central axis at the second position, the second edge having an inclusive angle of 120 degrees (claim 10 discloses having 120 degree orientation to each other). Regarding claim 18, Wallumrod discloses wherein positioning each limb around the central axis comprises positioning each limbs equally-spaced around the central axis (shown in figs 10-15 as equally spaced apart). Regarding claim 20, Wallumrod does not fully disclose wherein mutually connecting the first ends of the limbs and mutually connecting the second ends of the limbs comprises using an adhesive. However, Vollrath discloses wherein mutually connecting the first ends of the limbs and mutually connecting the second ends of the limbs comprises using an adhesive (claims 6 and 7 discloses an adhesive material to secure leg sections). It would have been obvious to one of ordinary skill in art before the effective filing date of the claimed invention to combine Wallumrod in view of Vollrath in order to properly hold the core together without electrical interference. Regarding claim 21, Wallumrod discloses prior to positioning each limb around a central axis, annealing each limb (par 41 discloses using cold rolled and hot rolled in the frame. Therefore, there is annealing in each limb). Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Wallumrod et al (EP2814045) in view of Vollrath et al (USPGPub 20110109412) in further view of Ishii et al (USPGPub 20200294702). Regarding claim 19, Wallumrod in view of Vollrath discloses wherein the insulating surface layer comprises a curable varnish, the method comprising, prior to positioning each limb around a central axis, curing the varnish in each limb. However, Ishii discloses wherein the insulating surface layer comprises a curable varnish, the method comprising, prior to positioning each limb around a central axis, curing the varnish in each limb (abstract and par 34 discloses a curable resin). It would have been obvious to one of ordinary skill in art before the effective filing date of the claimed invention to combine Wallumrod in view of Vollrath in further view of Ishii in order to have an excellent magnetic characteristic without press forming (Ishii par 34). Prior Art The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Kobayashi et al (USPGPub 20190295768): discloses a magnetic core with 3 sections. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to DOMINIC E HAWKINS whose telephone number is (571)272-2647. The examiner can normally be reached Monday-Friday 7:30am-5:00pm EST. 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, Judy Nguyen can be reached at (571) 272-2258. 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. /DOMINIC E HAWKINS/Primary Examiner, Art Unit 2858
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Prosecution Timeline

May 01, 2024
Application Filed
Jan 17, 2026
Non-Final Rejection — §102, §103, §112 (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

1-2
Expected OA Rounds
87%
Grant Probability
99%
With Interview (+12.1%)
2y 4m
Median Time to Grant
Low
PTA Risk
Based on 720 resolved cases by this examiner. Grant probability derived from career allow rate.

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