Prosecution Insights
Last updated: April 19, 2026
Application No. 18/505,598

INDUCTION ROTOR ASSEMBLY

Final Rejection §103
Filed
Nov 09, 2023
Examiner
STEFANON, JUSTIN
Art Unit
2834
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
GM Global Technology Operations LLC
OA Round
2 (Final)
51%
Grant Probability
Moderate
3-4
OA Rounds
3y 8m
To Grant
99%
With Interview

Examiner Intelligence

Grants 51% of resolved cases
51%
Career Allow Rate
94 granted / 183 resolved
-16.6% vs TC avg
Strong +48% interview lift
Without
With
+47.7%
Interview Lift
resolved cases with interview
Typical timeline
3y 8m
Avg Prosecution
50 currently pending
Career history
233
Total Applications
across all art units

Statute-Specific Performance

§101
1.0%
-39.0% vs TC avg
§103
34.1%
-5.9% vs TC avg
§102
38.4%
-1.6% vs TC avg
§112
25.2%
-14.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 183 resolved cases

Office Action

§103
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 filed 11/21/2025 have been fully considered but they are not persuasive. While Buttner does disclose that the grooves 24 are individually axially oriented, Buttner further discloses the grooves arranged in a series (see Figs. 16 and 34). This series extends radially outward, i.e. perpendicular to the longitudinal/axial direction. As such, “the plurality of serrations on the serrated surface extend perpendicular to the longitudinal axis” as broadly claimed. Likewise, each individual groove of Buttner has a radial dimension in which it extends, even though the longitudinal dimension may be greater. Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claims 1-6, 9-10, 12, and 21 are rejected under 35 U.S.C. 103 as being unpatentable over BUTTNER (US 20130187512) in view of KARLEN (previously cited; US 4249098). Regarding claim 1, BUTTNER discloses an induction rotor assembly, comprising: a laminated stack (1) including a body having a first end and an opposing second end arranged along a longitudinal axis (11), wherein the body has an outer circumferential surface extending from the first end to the second end along the longitudinal axis (11), wherein the outer circumferential surface has a plurality of grooves (3) extending from the first end to the second end;(see Fig.1-2 and para. [0090]) PNG media_image1.png 281 281 media_image1.png Greyscale PNG media_image2.png 276 375 media_image2.png Greyscale a plurality of conductor bars (4), wherein each of the plurality of conductor bars (4) is disposed within each of the grooves (3), and wherein each of the plurality of conductor bars (4) includes a first conductor end extending axially beyond the first end of the laminated stack (1) and a second conductor end extending axially beyond the second end of the laminated stack (1) (see Fig. 1 and 2), and wherein the first conductor end and the second conductor end of each of the plurality of conductor bars (4) includes a first serrated surface (20) and a second serrated surface (21) all having a plurality of serrations (24) wherein the serrations extend perpendicular to a longitudinal axis (11) of the plurality of conductor bars (see Fig. 16 and 34 and para [0102] and [0112]); PNG media_image3.png 225 305 media_image3.png Greyscale PNG media_image4.png 213 124 media_image4.png Greyscale a first end ring (5) having a plurality of serrated surfaces opposing and mating with the serrated surface of each first conductor end to interlock each of the plurality of conductor bars (4) to the first end ring (5) (see Fig. 16); and a second end ring (5) having a plurality of serrated surfaces opposing and mating with the serrated surface of each second conductor end to interlock each of the plurality of conductor bars (4) to the second end ring (5) (see Fig. 16), and wherein the plurality of conductor bars (4) extend between the first end ring (5) and the second end ring (5) (see Fig. 2). However, BUTTNER fails to disclose a third serrated surface. KARLEN discloses a rotor conductor bar 1 with a serrated surface 8 on its end face having a plurality of serrations wherein the serrations extend perpendicular to a longitudinal axis of the conductor bar 1 (see Fig. 4 and col. 4, lines 43-54). PNG media_image5.png 221 383 media_image5.png Greyscale Karlen It 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 to provide the rotor of BUTTNER with a conductor bar with a third serrated surface (on its end face) having a plurality of serrations wherein the serrations extend perpendicular to a longitudinal axis of the conductor bar, similar to that of KARLEN. A person having ordinary skill in the art to which the claimed invention pertains would have been motivated to make such modification in order to provide an even more secure attachment to the end ring with a significant reduction in solder (or other adhesive) required, as taught by KARLEN (see col. 4, lines 43-54). Regarding claim 2, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 1, wherein BUTTNER discloses the body includes a plurality of laminated steel sheets (see para [0090]). Regarding claim 3, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 1, wherein BUTTNER discloses the plurality of conductor bars (4) is formed from at least one of copper or aluminum (both; see para [0090]). Regarding claim 4, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 1, wherein BUTTNER discloses at least one of the plurality of conductor bars (4) includes an interlock feature (7) disposed as part of at least one of the first conductor end or a second conductor end, wherein the interlock feature (7) is configured to provide mechanical bonding to at least one of the first end ring (5) or the second end ring (5). (The interlock feature 7 includes a hole or other opening in the first end and/or the second end punched into and extending through the conductor bar 4. See Fig. 31 and para [0031]) PNG media_image6.png 241 379 media_image6.png Greyscale Regarding claim 5, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 1, wherein BUTTNER discloses the first end ring (5) and the second end ring (5) are each cast in place over the first conductor end and a second conductor end, respectively, of each of the plurality of conductor bars (4)(“A die-casting method is applied at the next step for producing the short-circuit rotor. Short-circuit rings that are in contact with the copper bars at their end face are produced by that method and the still free space in slots 3 simultaneously filled with a molten material.” Para [0090]). Regarding claim 6, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 5, wherein BUTTNER discloses the first end ring (5) and the second end ring (5) include and are formed from aluminum (see para [0091]). Regarding claim 9, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 1, wherein BUTTNER discloses the plurality of serrations (24) on the serrated surface [each] extend parallel to the longitudinal axis (11)(see Fig. 17). PNG media_image7.png 248 353 media_image7.png Greyscale Regarding claim 10, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 9, wherein the BUTTNER discloses plurality of serrations (24) [each] extend a full longitudinal length of each of the plurality of conductor bars (4)(see Fig. 17), and at least two surfaces of each of the plurality of conductor bars (4) include the serrated surface (see Fig. 18). Regarding claim 21, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 9, wherein BUTTNER discloses the plurality of serrations (26) have a sawtooth profile (see Fig. 34). Regarding claim 12, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 1, wherein BUTTNER discloses each of the plurality of serrations (24) includes a series of repeating half circle indentations (see Fig. 36). PNG media_image8.png 192 105 media_image8.png Greyscale Claims 7 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over BUTTNER in view KARLEN and further in view of PORCHER (US 20210135524). Regarding claim 7, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 1. However, BUTTNER in view of KARLEN does not teach each serration of the serrated surface has a depth of between 0.1 and 0.5 millimeters. PORCHER discloses a rotor (1) with a laminated stack (2) and conductor bars (10) having a plurality of serrations (5), each serration having a depth of between 0.1 and 0.5 millimeters (“between 0.4 and 0.6 mm, for example of 0.5 mm.” Para [0051].) It 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 to provide the rotor of BUTTNER in view of KARLEN with each serration of the serrated surface has a depth of between 0.1 and 0.5 millimeters, similar to PORCHER A person having ordinary skill in the art to which the claimed invention pertains would have been motivated to make such modification in order to provide clamping of the bars within the slot firm enough that each bar is immobilized both axially in the direction of the axis of rotation of the rotor, and radially. The bars can thus without moving withstand the pressure of the injection of the aluminum into the laminations stack, as taught by PORCHER. (see para [0052]) Regarding claim 8, BUTTNER in view of KARLEN teaches the induction rotor assembly of claim 1. However, BUTTNER in view of KARLEN does not teach serrations of the serrated surface have a pitch between 0.5 and 1.5 millimeters. PORCHER discloses a rotor (1) with a laminated stack (2) and conductor bars (10) having a plurality of serrations (5), the serrations of the serrated surface have a pitch approximately 0.5 and 1.5 millimeters. (“bosses 5 may have an amplitude of between 0.2 and 0.4 mm, for example of 0.3 mm.” Para [0051].) PORCHER teaches that arrangements of different amplitudes/pitches can be used in a conductor bar with serrations, making the amplitudes/pitches result effective variables, in order to improve immobilization during assembly. (see para [0052]) Thus, it 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 to arrange the serrations of BUTTNER in view of KARLEN according to the claimed pitch between 0.5 and 1.5 millimeters. A person having ordinary skill in the art to which the claimed invention pertains would have been motivated to make such modification in order to provide clamping of the bars within the slot firm enough that each bar is immobilized both axially in the direction of the axis of rotation of the rotor, and radially. The bars can thus without moving withstand the pressure of the injection of the aluminum into the laminations stack, as taught by PORCHER (see para [0052]), and since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art See In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980) Claims 13-15 are rejected under 35 U.S.C. 103 as being unpatentable over BUTTNER in view of KARLEN and further in view of MEYER (US 20130291373). Regarding claim 13, BUTTNER discloses an induction rotor assembly, wherein the induction rotor assembly includes a laminated stack (1) including a body having a first end and an opposing second end arranged along a longitudinal axis (11), the body having an outer circumferential surface extending from the first end to the second end along the longitudinal axis (11), the outer circumferential surface having a plurality of grooves (3) extending from the first end to the second end (see Fig. 1 and 2 and para. [0090]); a plurality of conductor bars (4), wherein each of the plurality of conductor bars (4) is disposed within each of the grooves (3), and wherein each of the plurality of conductor bars (4) includes a first conductor end extending axially beyond the first end of the laminated stack (1) and a second conductor end extending axially beyond the second end of the laminated stack (1), wherein the first conductor end and the second conductor end of each of the plurality of conductor bars (4) includes first serrated surface (20) and a second serrated surface (21) all having a plurality of serrations (24) (see Fig. 16 and 34 and para [0102] and [0112]); a first end ring (5) having a plurality of serrated surfaces opposing and mating with the serrated surface of each first conductor end to interlock each of the plurality of conductor bars (4) to the first end ring (5) (see Fig. 16); and a second end ring (5) having a plurality of serrated surfaces opposing and mating with the serrated surface of each second conductor end to interlock each of the plurality of conductor bars (4) to the second end ring (5) (see Fig. 16), and wherein the plurality of conductor bars (4) extends between the first end ring (5) and the second end ring (5) (see Fig. 2). However, BUTTNER does not disclose a third serrated surface. Neither does BUTTNER disclose a vehicle motor and a stator with the rotor configured to rotate due to a rotating magnetic field created by the stator. KARLEN discloses a rotor conductor bar 1 with a serrated surface 8 on its end face having a plurality of serrations wherein the serrations extend perpendicular to a longitudinal axis of the conductor bar 1 (see Fig. 4 and col. 4, lines 43-54). It 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 to provide the rotor of BUTTNER with a conductor bar with a third serrated surface (on its end face) having a plurality of serrations wherein the serrations extend perpendicular to a longitudinal axis of the conductor bar, similar to that of KARLEN. A person having ordinary skill in the art to which the claimed invention pertains would have been motivated to make such modification in order to provide an even more secure attachment to the end ring with a significant reduction in solder (or other adhesive) required, as taught by KARLEN (see col. 4, lines 43-54). MEYER discloses an induction rotor assembly (4) with a plurality of conductor bars (8) with serrated surfaces (53,54) in a vehicle motor (1) and a stator (2) with the rotor configured to rotate due to a rotating magnetic field created by the stator (see para [0026]) It 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 to provide the rotor of BUTTNER in view of KARLEN in a vehicle motor with a stator with the rotor configured to rotate due to a rotating magnetic field created by the stator, similar to MEYER. A person having ordinary skill in the art to which the claimed invention pertains would have been motivated to make such modification in order to provide an electric motor for a vehicle with reduced friction, reduced inter-bar current, and reduced energy losses as taught by MEYER (see para [0015-0019]) Regarding claim 14, BUTTNER in view KARLEN and further in view of MEYER teaches the induction rotor assembly of claim 13, wherein BUTTNER discloses the plurality of conductor bars (4) is formed from at least one of copper or aluminum (both; see para [0090]). Regarding claim 15, BUTTNER in view KARLEN and further in view of MEYER teaches the induction rotor assembly of claim 13, wherein BUTTNER discloses at least one of the plurality of conductor bars (4) includes an interlock feature (7) disposed as part of at least one of the first conductor end or the second conductor end, wherein the interlock feature (7) is configured to provide mechanical bonding to at least one of the first end ring (5) or the second end ring (5) (The interlock feature 7 includes a hole or other opening in the first end and/or the second end punched into and extending through the conductor bar 4. See Fig. 31 and para [0031]). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US-20150303781-A1 Brandl discloses a conductor bar with three serrated surfaces (see Figs. 2-4). 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 JUSTIN STEFANON whose telephone number is (703)756-4648. The examiner can normally be reached Monday - Thursday and alternate Fridays 8AM - 5PM EDT. 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, Oluseye Iwarere can be reached at (571) 270-5112. 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. /JUSTIN STEFANON/Examiner, Art Unit 2834 /OLUSEYE IWARERE/Supervisory Patent Examiner, Art Unit 2834
Read full office action

Prosecution Timeline

Nov 09, 2023
Application Filed
Sep 08, 2025
Non-Final Rejection — §103
Nov 21, 2025
Response Filed
Mar 07, 2026
Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12494684
ROTOR OF AN ELECTRIC MACHINE
2y 5m to grant Granted Dec 09, 2025
Patent 12451742
METHOD AND APPARATUS FOR COOLING A ROTOR ASSEMBLY
2y 5m to grant Granted Oct 21, 2025
Patent 12316190
CASE STRUCTURE OF IN-WHEEL MOTOR
2y 5m to grant Granted May 27, 2025
Patent 9650015
BELT RETRACTOR FOR A VEHICLE SAFETY BELT
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Patent 9635986
SPINDLE AND ADAPTER FOR ROLL PAPER PRODUCT DISPENSERS
2y 5m to grant Granted May 02, 2017
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
51%
Grant Probability
99%
With Interview (+47.7%)
3y 8m
Median Time to Grant
Moderate
PTA Risk
Based on 183 resolved cases by this examiner. Grant probability derived from career allow rate.

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