Prosecution Insights
Last updated: April 19, 2026
Application No. 18/748,556

SYSTEM AND METHOD FOR COOLING CARBON BRUSHES AND SLIP RINGS

Non-Final OA §102§103
Filed
Jun 20, 2024
Examiner
QURESHI, MOHAMMED AHMED
Art Unit
2834
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Dana Automotive Systems Group LLC
OA Round
1 (Non-Final)
85%
Grant Probability
Favorable
1-2
OA Rounds
2y 5m
To Grant
93%
With Interview

Examiner Intelligence

Grants 85% — above average
85%
Career Allow Rate
132 granted / 156 resolved
+16.6% vs TC avg
Moderate +9% lift
Without
With
+8.8%
Interview Lift
resolved cases with interview
Typical timeline
2y 5m
Avg Prosecution
29 currently pending
Career history
185
Total Applications
across all art units

Statute-Specific Performance

§101
0.9%
-39.1% vs TC avg
§103
49.6%
+9.6% vs TC avg
§102
27.5%
-12.5% vs TC avg
§112
20.7%
-19.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 156 resolved cases

Office Action

§102 §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 . 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. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. Claim(s) 1, 6-8, 10, and 16-18 is/are rejected under 35 U.S.C 102(a)(1) and/or 102(a)(2) as being unpatentable over FLOSS(US20210036582A1). Regarding claim 1, Floss teaches an electric machine(1), comprising: a rotor(2) including a first slip ring(7) and a second slip ring(7), the rotor including a shaft(4); one or more coolant passages(17) arranged to supply coolant to cool the first slip ring(7) and the second slip ring(7); a first brush(10) in contact with the first slip ring(7) and a second brush(10) in contact with the second slip ring(7); and a stator(3)(Figs. 1-3). Regarding claim 6/1, Floss teaches the electric machine of claim 3. Floss teaches further teaches where the first slip ring(7) and the second slip ring(7) are included in a slip ring module(6)(Figs. 1-3). Regarding claim 7/6, Floss teaches the electric machine of claim 3. Floss teaches further teaches where the slip ring module(6) is fitted to the shaft(4)(Figs. 1-3). Regarding claim 8, Floss teaches a method for cooling slip rings(7) of an electric machine(1), comprising: inserting a flow distribution device(5) into a rotor shaft(4) of the electric machine; and flowing a coolant past or through the flow distribution device(5) to a first slip ring(7) and a second slip ring(7)(Figs. 1-3). Regarding claim 10/8, Floss teaches the method of claim 8. Floss further teaches installing a slip ring module(6) to the rotor shaft(4), where the slip ring module includes the first slip ring(7) and the second slip ring(7)(Figs. 1-3). Regarding claim 16, Floss teaches a slip ring module(6), comprising: an annular body(rotor body 2 and rotor shaft 4); a first slip ring(7) and a second slip ring(7) fixed to the annular body(2,4); and a fluid flow distribution device(5) inserted into the annular body(2,4)(Figs. 1-3). Regarding claim 17/16, Floss teaches the slip ring module of claim 16. Floss further teaches comprising one or more coolant passages(17) within the annular body(2,4)(Figs. 1-3). Regarding claim 18/16, Floss teaches the slip ring module of claim 16. Floss further teaches comprising one or more coolant passages(17) within the fluid flow distribution device(5) (Figs. 1-3). 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. Claim(s) 2-5 and 9 is/are rejected under 35 U.S.C 103 as being unpatentable over FLOSS(US2021036582A1) in view of MAYTONE(US3316519A). Regarding claim 2/1, Floss teaches the electric machine of claim 1. Floss doesn’t explicitly teach where the one or more coolant passages are arranged such that coolant flowing through the one or more coolant passages directly contacts the first slip ring and the second slip ring. However, Maytone teaches where the one or more coolant passages(15,16) are arranged such that coolant flowing through the one or more coolant passages directly contacts the first slip ring(5) and the second slip ring(5)(Figs. 1-3). Maytone is considered to be analogous to the claimed invention of Floss because they are in the same field of electric machines. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have further modified Floss where the one or more coolant passages are arranged such that coolant flowing through the one or more coolant passages directly contacts the first slip ring and the second slip ring, as taught by Maytone. One would be motivated to do this in order to improve heat dissipation at the slip ring which increases cooling and efficiency. Regarding claim 3/2, Floss in view Maytone teaches the electric machine of claim 2. Floss teaches further teaches comprising a fluid flow distribution device(5) inserted into the shaft(4)(Figs. 1-3). Regarding claim 4/3, Floss in view Maytone teaches the electric machine of claim 3. Floss teaches further teaches where the fluid flow distribution device(5) includes the one or more coolant passages(17)(Figs. 1-3). Regarding claim 5/3, Floss in view Maytone teaches the electric machine of claim 3. Floss teaches further teaches where the shaft(4) includes the one or more coolant passages(17)(Figs. 1-3). Regarding claim 9/8, Floss teaches the method of claim 8. Floss doesn’t explicitly teach where the coolant flows in direct contact with the first slip ring and the second slip ring. However, Maytone teaches where the one or more coolant passages(15,16) are arranged such that coolant flowing through the one or more coolant passages directly contacts the first slip ring(5) and the second slip ring(5)(Figs. 1-3). Maytone is considered to be analogous to the claimed invention of Floss because they are in the same field of electric machines. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have further modified Floss where the coolant flows in direct contact with the first slip ring and the second slip ring. as taught by Maytone. One would be motivated to do this in order to improve heat dissipation at the slip ring which increases cooling and efficiency. Claim(s) 11-15 and 19-20 is/are rejected under 35 U.S.C 103 as being unpatentable over FLOSS(US2021036582A1) in view of DONLEY(US3560004A). Regarding claim 11/8, Floss teaches the method of claim 8. Floss is silent where the flow distribution device includes a first longitudinal bore hole and a second longitudinal bore hole. However, Donley teaches where the flow distribution device(internal walls of 46) includes a first longitudinal bore hole(47) and a second longitudinal bore hole(53)(Fig. 4). Donley is considered to be analogous to the claimed invention of Floss because they are in the same field of electric machines. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have further modified Floss where the flow distribution device includes a first longitudinal bore hole and a second longitudinal bore hole, as taught by Donley. One would be motivated to do this in order to improve coolant distribution and heat transfer within the rotor shaft. Regarding claim 12/11, Floss in view of Donley teaches the method of claim 11. Donley further teaches where the flow distribution device(internal walls of 46) includes a first plurality of through holes(54,55) extending into the first longitudinal bore hole(47), and where the flow distribution device includes a second plurality of through holes(54,55) extending into the second longitudinal bore hole(53)(Fig. 4). Regarding claim 13/8, Floss teaches the method of claim 8. Floss is silent where flowing coolant past or through the flow distribution device includes pumping the coolant. However, Donley teaches where flowing coolant past or through the flow distribution device(internal walls of 46) includes pumping the coolant(Pumping through centrifugal action. Also in Col.7, Lines 43-64 discloses adding a pump to force fluid through the heat transfer system). Donley is considered to be analogous to the claimed invention of Floss because they are in the same field of electric machines. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have further modified Floss where flowing coolant past or through the flow distribution device includes pumping the coolant, as taught by Donley. One would be motivated to do this in order to improve fluid circulations and cooling efficiency. Regarding claim 14/8, Floss teaches the method of claim 8. Floss is silent further comprising adjusting a flow rate of the coolant in response to a rotational speed of the electric machine. However, Donley teaches centrifugal pumping action increases with shaft rotational speed(Col.4, Lines 1-27, Therefore the coolant flow rate is inherently adjusted as operating speed changes). Donley is considered to be analogous to the claimed invention of Floss because they are in the same field of electric machines. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have further modified Floss adjusting a flow rate of the coolant in response to a rotational speed of the electric machine, as taught by Donley. One would be motivated to do this in order to increase coolant flow during higher speed operations when greater frictional heating occurs, thereby improving efficiency and cooling. Regarding claim 15/14, Floss in view of Donley teaches the method of claim 14. Floss further teaches comprising flowing the coolant through the rotor shaft(4)(Figs. 1-3). Regarding claim 19/16, Floss teaches the slip ring module of claim 16. Floss is silent comprising a first bore hole and a second bore hole, the first bore hole and the second bore hole oriented in a longitudinal direction of the fluid flow distribution device. However, Donley teaches where the flow distribution device(internal walls of 46) includes a first longitudinal bore hole(47) and a second longitudinal bore hole(53)(Fig. 4). Donley is considered to be analogous to the claimed invention of Floss because they are in the same field of electric machines. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have further modified Floss comprising a first bore hole and a second bore hole, the first bore hole and the second bore hole oriented in a longitudinal direction of the fluid flow distribution device, as taught by Donley. One would be motivated to do this in order to improve coolant distribution and heat transfer within the rotor shaft. Regarding claim 20/19, Floss in view of Donley teaches the slip ring module of claim 19. Donley further teaches wherein comprising a plurality of through holes(47,53) included in the fluid flow distribution device(Internal walls of 46)(Fig. 4). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to MOHAMMED QURESHI whose telephone number is (571)-272-8310. The examiner can normally be reached on 8:30 AM - 6:00 PM. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Tulsidas Patel can be reached on 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 an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pairdirect. uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). /MOHAMMED AHMED QURESHI/Examiner, Art Unit 2834 /TULSIDAS C PATEL/Supervisory Patent Examiner, Art Unit 2834
Read full office action

Prosecution Timeline

Jun 20, 2024
Application Filed
Mar 05, 2026
Non-Final Rejection — §102, §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

1-2
Expected OA Rounds
85%
Grant Probability
93%
With Interview (+8.8%)
2y 5m
Median Time to Grant
Low
PTA Risk
Based on 156 resolved cases by this examiner. Grant probability derived from career allow rate.

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