Prosecution Insights
Last updated: April 19, 2026
Application No. 18/377,170

STATOR COOLING

Final Rejection §103§112
Filed
Oct 05, 2023
Examiner
MULLINS, BURTON S
Art Unit
2834
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
CUMMINS INC.
OA Round
2 (Final)
69%
Grant Probability
Favorable
3-4
OA Rounds
2y 11m
To Grant
70%
With Interview

Examiner Intelligence

Grants 69% — above average
69%
Career Allow Rate
899 granted / 1305 resolved
+0.9% vs TC avg
Minimal +1% lift
Without
With
+0.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
41 currently pending
Career history
1346
Total Applications
across all art units

Statute-Specific Performance

§101
1.2%
-38.8% vs TC avg
§103
43.4%
+3.4% vs TC avg
§102
24.8%
-15.2% vs TC avg
§112
28.3%
-11.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1305 resolved cases

Office Action

§103 §112
DETAILED ACTION 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. Claims 13 & 15-17 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. Claims 13 & 15-17 depend from canceled claim 11. For purposes of examination, they will be understood to depend from claim 1. Claim 16 is further indefinite because it is unclear how and/or in what sense the cooling passage comprises the claimed features when claim 1 states that the cooling passage is “in the stator yoke” and comprises a U-shaped annular trough extending circumferentially “around the outside of the stator yoke.” 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 1-9, 13 & 15-20 are rejected under 35 U.S.C. 103 as being unpatentable over Cherney (US 9,148,034) in view of Garety (US Pat.Pub.2023/0198320). Regarding claim 1, Cherney teaches a stator 14 for an electrical machine, the stator comprising: a stator yoke (i.e., stator 14); a plurality of stator teeth 40 extending radially inwards from the stator yoke, the stator teeth defining stator slots 42 for stator windings (coils) 22; a plurality of auxiliary teeth (not numbered) extending radially inwards from the stator yoke into the stator slots, wherein at least some of the auxiliary teeth comprise cooling channels (flow apertures) 50/52 (Fig.2), and a conduit (circumferential passageway) 54 arranged to carry coolant circumferentially around the stator and into the cooling channels 50/52 in the auxiliary teeth, the conduit comprising a cooling passage (Figs.1-2&6). PNG media_image1.png 553 476 media_image1.png Greyscale Cherney does not further teach the conduit/cooling passage 54 is “in the stator yoke” and comprises “a U-shaped annular trough extending circumferentially around the outside of the stator yoke.” But, Garety teaches a fluid cooled stator with a conduit/cooling passage (annulus groove) 28 in the stator yoke (i.e., on the outside of stator core 21) that comprises a U-shaped annular trough extending circumferentially around the outside of the stator yoke (¶[0022]- ¶[0023]; Fig.3). Cooling fluid flowing in axial grooves from the first and second ends of the stator core is collected in the annulus groove 28 and flows around the circumference of the stator core in the groove, thus providing cooling of the stator (¶[0001]; ¶[0016]; ¶[0023]). PNG media_image2.png 556 438 media_image2.png Greyscale It would have been obvious before the effective filing date to provide Cherney with a conduit/cooling passage in the stator yoke and comprising a U-shaped annular trough extending circumferentially around the outside of the stator yoke since Garety teaches this would have provided cooling of the stator. Regarding claim 2, Cherney’s stator windings comprise a plurality of pre-formed coils; each coil is arranged to be slid onto one of the stator teeth 40; 1 and each auxiliary tooth extends radially inwards from the stator yoke into a stator slot 42 between the coils of two adjacent stator teeth (Fig.2). Regarding claim 3, Cherney’s auxiliary teeth have a width in a tangential direction which decreases with increasing distance into the stator slot from the stator yoke (Fig.2). Regarding claim 4, each of Cherney’s auxiliary teeth substantially fills a gap between the stator windings 22 of two adjacent teeth (Fig.2). Regarding claim 5, Cherney’s stator windings 22 comprise pre-formed coils 2 of rectangular wire (Fig.2). Regarding claim 6, each of Cherney’s coils 22 comprises a plurality of turns of rectangular wire, and each turn comprises a single width of rectangular wire (Figs.1-2). Regarding claim 7, Cherney’s auxiliary teeth are arranged to conduct heat from the stator windings 22 to the stator yoke (inherent; Fig.2). Regarding claim 8, Cherney’s cooling channels 50/52 run axially through the auxiliary teeth (Fig.2). Regarding claim 9, Cherney’s cooling channels 50/52 are arranged to convey a liquid coolant (abstract), as are Garety’s (abstract). Regarding claim 13, Garety’s cooling passage (annulus groove) 28 is located at or towards the cent[er], axially, of the stator yoke (Fig.3). Regarding claim 15, Garety’s stator comprises a plurality of stacked stator laminations 7, and the cooling passage (annulus groove) 28 is formed by providing a group of stator laminations with an outside diameter which is less than that of other stator laminations (Fig.3). Regarding claim 16, Garety’s stator comprises a plurality of stacked stator laminations 7, and the cooling passage (annulus groove) 28 is formed by providing a ring of material (not numbered) between two groups of stator laminations, the ring of material having an outside diameter which is less than that of the laminations (Figs.3&6). Regarding claim 17, in the combination, Garety’s cooling passage (annulus groove) 28 is arranged to carry coolant circumferentially around the stator yoke (Fig.3) and Cherney’s cooling channels 50/52 are arranged to carry coolant axially through the auxiliary teeth (Figs.5-6). Regarding claim 18, in Cherney the stator comprises a plurality of stacked laminations 24 and the auxiliary teeth are formed from the same laminations as the stator yoke (Fig.2). Regarding claim 19, the grounds of rejection are the same as for claim 1 above. It is noted Cherney additionally teaches a rotor 12 and a cooling circuit (Fig.5) arranged to circulate coolant through the cooling channels 50/52 in the auxiliary teeth. Regarding method claim 20, the grounds of rejection is the same for corresponding apparatus claim 1 above since the method is inherent to the structure of the combination. Claims 1-9, 13 & 15-20 are rejected under 35 U.S.C. 103 as being unpatentable over Sadarangani et al. (EP 2136455) in view of Bradfield et al. (US 8,395,287). Regarding claim 1, Sadarangani teaches a stator 1 for an electrical machine, the stator comprising: a stator yoke 2; a plurality of stator teeth 4 extending radially inwards from the stator yoke, the stator teeth defining stator slots 8 for stator windings (coils) 6; a plurality of auxiliary (intermediate) teeth 16 extending radially inwards from the stator yoke into the stator slots, wherein at least some of the auxiliary teeth comprise cooling channels (cooling duct) 20 (¶[0023]; Fig.4); and a conduit arranged to carry coolant…into the cooling channels [20] in the auxiliary teeth [16] (i.e., cooling medium circulates in cooling ducts; ¶[0022]). PNG media_image3.png 380 451 media_image3.png Greyscale Sadarangani does not further teach a conduit arranged to carry coolant “circumferentially around the stator and into the cooling channels [20] in the auxiliary teeth [16]…the conduit comprising a cooling passage in the stator yoke, the cooling passage comprising a U-shaped annular trough extending circumferentially around the outside of the stator yoke.” But, Bradfield teaches a stator 26 with coolant channels for an electrical machine comprising conduits arranged to carry coolant circumferentially around the stator and comprising cooling passages (circumferential coolant channels) 40 in the stator yoke, the cooling passage comprising a U-shaped annular trough 40 extending circumferentially around the outside of the stator yoke (Figs.3&4B). The coolant channels, by being integral with the stator, transfer heat at a quicker rate (c.5:18-29). PNG media_image4.png 445 452 media_image4.png Greyscale PNG media_image5.png 216 453 media_image5.png Greyscale Thus, it would have been obvious before the effective filing date to provide Sadarangani with a conduit arranged to carry coolant circumferentially around the stator and into the cooling channels in the auxiliary teeth, the conduit comprising a cooling passage in the stator yoke, the cooling passage comprising a U-shaped annular trough extending circumferentially around the outside of the stator yoke since Bradfield teaches such a coolant channel would have transferred heat at a quicker rate. Regarding claim 2, Sadarangani’s stator windings (coils) 6 comprise a plurality of pre-formed coils; each coil is arranged to be slid onto one of the stator teeth 4; 3 and each auxiliary tooth 16 extends radially inwards from the stator yoke 2 into a stator slot 8 between the coils of two adjacent stator teeth (Fig.4). Regarding claim 3, Sadarangani’s auxiliary teeth 18 have a width in a tangential direction which decreases with increasing distance into the stator slot 8 from the stator yoke 2 (Fig.4). Regarding claim 4, in Sadarangani each auxiliary tooth 18 substantially fills a gap between the stator windings 6 of two adjacent teeth (Fig.4). Regarding claim 5, in Sadarangani the stator windings (coils) 6 comprise pre-formed coils 4 of rectangular wire (abstract; Fig.4). Regarding claim 6, in Sadarangani each coil 6 comprises a plurality of turns of rectangular wire, and each turn comprises a single width of rectangular wire (abstract; Fig.4). Regarding claim 7, in Sadarangani the auxiliary teeth 18 are arranged to conduct heat from the stator windings (coils) 6 to the stator yoke 2 (since intermediate teeth are one piece with yoke; ¶[0022]; Fig.4). Regarding claim 8, in Sadarangani the cooling channels 20 run axially through the auxiliary teeth 18 (Fig.4). Regarding claim 9, in Sadarangani the cooling channels 20 are arranged to convey a liquid coolant (¶[0023]). Bradfield’s channels also convey liquid coolant (c.4:3-15). Regarding claim 13, Bradfield’s cooling passages are located at or towards the center, axially, of the stator yoke (Fig.3). Regarding claim 15, Bradfield’s stator comprises a plurality of stacked stator laminations 28, and the cooling passage 40 is formed by providing a group of stator laminations with an outside diameter (R2) which is less than that of other stator laminations (i.e., laminations with radius R1; c.3:25-52; Figs.2-3). Regarding claim 16, Bradfield’s stator comprises a plurality of stacked stator laminations 28, and the cooling passage 40 is formed by providing a ring of material (i.e., stator laminations with radius R2) between two groups of stator laminations, the ring of material having an outside diameter which is less than that of the laminations (with radius R1; c.3:25-52; Figs.2-3). Regarding claim 17, in the combination, Bradfield’s cooling passage 40 is arranged to carry coolant circumferentially around the stator yoke (Figs.3&4B) and Sadarangani’s cooling ducts 20 are arranged to carry coolant axially through the auxiliary teeth (Fig.4). Regarding claim 18, Bradfield teaches the stator comprising a plurality of stacked laminations 28 (c.3:6-7) and Sadarangani teaches the auxiliary teeth 16 are formed from the same laminations as the stator yoke (¶[0022]). Regarding claim 19, the grounds of rejection are the same as for claim 1 above. It is further noted Sadarangani’s electrical machine comprises a rotor (not numbered; abstract), and a cooling circuit arranged to circulate coolant through…the cooling channels 20 in the auxiliary teeth 18 (i.e., cooling system circulates cooling medium through ducts; ¶[0023]). Regarding method claim 20, the grounds of rejection is the same for corresponding apparatus claim 1 above since the method is inherent to the structure of the combination. Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Cherney & Garety or Sadarangani & Bradfield as applied to claims 1, further in view of Adra (US Pat.Pub. 2006/0043801). None of the combinations further teach the conduit comprises a pipe and a plurality of ports. But, Adra teaches a liquid cooled electric machine comprising at least one annular pipe (inlet manifold) 70 (or outlet manifold 72) located outside of and axially adjacent to at least one end face of a stator yoke (stator) 38 (Fig.2); and a plurality of ports (not numbered, correspon-ding to tubes 74), each port having a first portion (not numbered) extending radially inwards from the annular pipe 70/72 toward a center of the stator yoke and a second portion (not numbered) extending axially from the first portion toward one of the cooling channels (formed by tubes 74; Figs.2&4). Adra’s annular pipe/inlet manifold 70 with plural ports directs the heat-transferring medium from cooling system 14 through tubes 74 and the outlet manifold 72 directs heat-transferring medium from the tubes 74 to the cooling system 14, to thereby remove heat from the windings and stator (¶[0027]). PNG media_image6.png 595 437 media_image6.png Greyscale PNG media_image7.png 414 465 media_image7.png Greyscale Thus, it would have been obvious before the effective filing date to provide Cherney or Sadarangani with at least one annular pipe and a plurality of ports since Adra teaches this would have been desirable to direct heat-transferring medium to and from a cooling system to the conduits to thereby remove heat from the windings and stator. Claims 21-22 are rejected Cherney & Garety or Sadarangani & Bradfield as applied to claims 1 and 19, further in view of Houle et al. (US 6,819,016). None of Cherney & Garety or Sadarangani & Bradfield further teach the U-shaped annular trough is “fitted with an annular pipe therein, the annular pipe comprising a port configured to receive the coolant and to flow the coolant through the cooling channels.” But, Houle teaches a liquid cooling arrangement for a stator (embodiments include external stator; c.4:52-57) comprising C-shaped channels 104 in a heat storing element 102 and an annular pipe (cooling tube) 106 therein, the cooling tube comprising a port (inlet) 110 configured to receive the coolant and to flow the coolant through the cooling channels (abstract; c.4:8-40; Figs.6-9). Houle teaches that prior art machines using laminations provided with apertures allowing flow of cooling liquid risked failure caused by leaks should the seal between adjacent laminations fail, whereas use of pipes (tubes) inserted in channels prevents this and allows heat to be extracted (c.1:25-34; c.2:45-50). PNG media_image8.png 655 450 media_image8.png Greyscale Thus, it would have been obvious to fit the U-shaped trough of Cherney & Garety or Sadarangani & Bradfield with an annular pipe therein, the annular pipe comprising a port configured to receive the coolant and to flow the coolant through the cooling channels, since Houle teaches a pipe would have been desirable to extract heat and simultaneously prevent leaks should the seal between adjacent laminations fail. Claim 23 is rejected under 35 U.S.C. 103 as being unpatentable over Cherney or Sadarangani, further in view of Adra. As noted above in the respective rejections of claim 1, Cherney and Sadarangani each teach the claimed features except for “at least one annular pipe located outside of and axially adjacent to at least one end face of the stator yoke; and a plurality of ports, each port having a first portion extending radially inwards from the annular pipe toward a center of the stator yoke and a second portion extending axially from the first portion toward one of the cooling channels in the auxiliary teeth.” But, Adra teaches a liquid cooled electric machine comprising at least one annular pipe (inlet manifold) 70 (or outlet manifold 72) located outside of and axially adjacent to at least one end face of a stator yoke (stator) 38 (Fig.2); and a plurality of ports (not numbered, corresponding to tubes 74), each port having a first portion (not numbered) extending radially inwards from the annular pipe 70/72 toward a center of the stator yoke and a second portion (not numbered) extending axially from the first portion toward one of the cooling channels (formed by tubes 74; Figs.2&4). Adra’s annular inlet manifold 70 with plural ports directs the heat-transferring medium from cooling system 14 through tubes 74 and the outlet manifold 72 directs heat-transferring medium from the tubes 74 to the cooling system 14, to thereby remove heat from the windings and stator (¶[0027]). Thus, it would have been obvious before the effective filing date to provide Cherney or Sadarangani with at least one annular pipe located outside of and axially adjacent to at least one end face of the stator yoke; and a plurality of ports, each port having a first portion extending radially inwards from the annular pipe toward a center of the stator yoke and a second portion extending axially from the first portion toward one of the cooling channels in the auxiliary teeth, since Adra teaches this would have been desirable to direct heat-transferring medium to and from a cooling system to the conduits to thereby remove heat from the windings and stator. Response to Arguments Applicant’s arguments with respect to independent claims 1, 19-20 & 23 have been considered but are moot in view of the new grounds of rejection. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. In particular, multiple references read on newly added claim features, including Lin et al. (CN 113746228) who teaches a cooling conduit arranged to carry coolant circumferentially around stator 20, the conduit comprising a cooling passage 31 in the stator yoke 21, the cooling passage comprising a U-shaped annular trough 31 extending circumferentially around the outside of the stator yoke (Fig.3). Krastchew (US 3,681,628) teaches a stator for an electrical machine including at least one annular pipe (inlet header) 12 located outside of and axially adjacent to at least one end face of the stator yoke 1; and a plurality of ports (hoses) 15, each port 15 having a first portion (not numbered) extending radially inwards from the annular pipe 12 toward a center of the stator yoke and a second portion (not numbered) extending axially from the first portion toward one of the cooling channels 7 (c.7:25-42; Fig.9). Lee (US 9,985,489) teaches circulation cooling of a generator stator bar with a conduit arranged to carry coolant into cooling channels 500, the conduit comprising at least one annular pipe (coolant supply ring) 200 located outside of and axially adjacent to at least one end face of the stator yoke (not shown, inherent); and a plurality of ports (coupling hoses) 11, 13, 14, each port having a first portion (e.g., hose portion 113; Fig.4) extending radially inwards from the annular pipe 200 toward a center of the stator yoke and a second portion (adjacent ports 111/112) extending axially from the first portion toward one of the cooling channels 500 (c.7:1-50; Figs.2,4&13). 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 BURTON S MULLINS whose telephone number is (571)272-2029. The examiner can normally be reached 9-5. 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, Tulsidas C Patel can be reached at 571-272-2098. 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. /BURTON S MULLINS/Primary Examiner, Art Unit 2834 1 These product-by-process features are not given patentable weight. Per MPEP 2113 (I), product-by-process claims are not limited to the manipulations of the recited steps, only the structure implied by the steps. "[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process." In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). 2 Ibid. 3 Ibid. 4 Ibid.
Read full office action

Prosecution Timeline

Oct 05, 2023
Application Filed
Sep 24, 2025
Non-Final Rejection — §103, §112
Dec 30, 2025
Response Filed
Mar 03, 2026
Final Rejection — §103, §112 (current)

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Prosecution Projections

3-4
Expected OA Rounds
69%
Grant Probability
70%
With Interview (+0.7%)
2y 11m
Median Time to Grant
Moderate
PTA Risk
Based on 1305 resolved cases by this examiner. Grant probability derived from career allow rate.

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