Prosecution Insights
Last updated: April 19, 2026
Application No. 18/250,558

PISTON RINGS AND METHODS OF MANUFACTURE

Final Rejection §103
Filed
Apr 26, 2023
Examiner
TALBOT, BRIAN K
Art Unit
1712
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Nanofilm Vacuum Coating (Shanghai) Co. Ltd.
OA Round
4 (Final)
59%
Grant Probability
Moderate
5-6
OA Rounds
3y 4m
To Grant
90%
With Interview

Examiner Intelligence

Grants 59% of resolved cases
59%
Career Allow Rate
680 granted / 1151 resolved
-5.9% vs TC avg
Strong +31% interview lift
Without
With
+31.2%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
58 currently pending
Career history
1209
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
62.0%
+22.0% vs TC avg
§102
12.3%
-27.7% vs TC avg
§112
21.6%
-18.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1151 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 . The response filed 10/6/25 has been considered and entered. Claims 1-26,28 and 33 have been canceled. Claims 39-44 have been withdrawn. Hence, claims 27,29-32 and 34-38 remain in the application for prosecution thereof. Considering the amendment filed 3/27/25, the 35 USC 103 rejections have been withdrawn, however, the following rejections have been necessitated by the amendment. The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim Rejections - 35 USC § 103 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 (i.e., changing from AIA to pre-AIA ) 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 27,29-32 and 34-38 are rejected under 35 U.S.C. 103 as being unpatentable over Nishimura et al. (2005/0005892) in combination with EP 3636795 or Rajagopalan et al. (2012/0178637) further in combination with Tsuji (2016/0178054) further in combination with Miyazaki et al. (5,582,414). Nishimura et al. (2005/0005892) teaches piston for internal combustion engine and coating a hard carbon thin film on the sliding section of the piston ring having less than 1% hydrogen (abstract and [0013]). Nishimura et al. (2005/0005892) teaches coating an upper lower and side surfaces of the piston ring with an amorphous carbon coating (a-c) ([0029],[0092] and Fig 4A and 4B). Nishimura et al. (2005/0005892) fails to teach the amorphous carbon coating to be tetrahedral amorphous coating (ta-C). Rajagopalan et al. (2012/0178637) teaches a low fuel injector for combustion engine whereby a piston or ring can be coated with a low friction carbon including amorphous carbon (a-c) and tetrahedral amorphous carbon (ta-C) (abstract and [0078]). Rajagopalan et al. (2012/0178637) teaches vickers hardness of 4500-6000 HV [0068]-[0070]. EP 3636795 teaches thick low stress tetrahedral amorphous carbon coatings for piston rings (abstract and [0037]) as well as the vickers hardness of the coating ta-C coating [0036]. Therefore, it would have been obvious for one skilled in the art before the effective filing date of the claimed invention to have modified Nishimura et al. (2005/0005892) process to include a ta-C coating as evidenced by Rajagopalan et al. (2012/0178637) or EP 3636795 with the expectation of achieving similar success. Nishimura et al. (2005/0005892) in combination with EP 3636795 or Rajagopalan et al. (2012/0178637) fails to teach the coating of more than one piston ring, spacing these piston rings from one another, rotating the piston rings during coating and coating beam being horizontal/orthogonal to the piston ring. Tsuji (2016/0178054) teaches coating a piston ring with a hard carbon coating using a jig (124) to allow for multiple piston rings to be coated simultaneously whereby the jig can be rotated while coating thereon (Figs. 7 and 9 and [0061]-[0066]). Therefore, it would have been obvious for one skilled in the art before the effective filing date of the claimed invention to have modified Nishimura et al. (2005/0005892) in combination with EP 3636795 or Rajagopalan et al. (2012/0178637) process to coat more than one piston ring by spacing them apart and rotating during coating as evidenced by Tsuji (2016/0178054) with the expectation of achieving similar success and faster production and reducing throughput. Nishimura et al. (2005/0005892) in combination with EP 3636795 or Rajagopalan et al. (2012/0178637) further in combination with Tsuji (2016/0178054) fails to teach a single source coating and not multiple sources. Wang et al. "The preparation and evaluation of graded multilayered ta-C films deposited by FCVA method" teaches coating ta-C by FCVA methods produce decrease stress level coatings with improved hardness, wettability and optical refractive indexes (abstract and paragraphs 3.1-3.6). Therefore, it would have been obvious for one skilled in the art before the effective filing date of the claimed invention to have modified Nishimura et al. (2005/0005892) in combination with EP 3636795 or Rajagopalan et al. (2012/0178637) further in combination with Tsuji (2016/0178054) process to include a single cathode arc coating source as evidenced by Wang et al. "The preparation and evaluation of graded multilayered ta-C films deposited by FCVA method" with the expectation of producing the coating with these characteristics on a high adhesion and density. It is noted that FCVA is a single source coating method which is directs coating beam orthogonal to the substrate and hence inherently teaches the claimed limitations. Regarding claim 28, EP 3636795 and Wang et al. "The preparation and evaluation of graded multilayered ta-C films deposited by FCVA method" teach filtered cathode vacuum arc process and the filtered FCVA [0028]-[0032] and Tsuji (2016/0178054) teaches cathode arc evaporation [0063]. Regarding claims 27 and 35, Miyazaki et al. (5,582,414) depicts that the angle is orthogonal to the substrates (12) in the coating vacuum chamber (10). Regarding claims 29,31,32 and 35, Tsuji (2016/0178054) teaches coating multiple piston rings and rotation thereof during coating. Regarding claims 30 and 31, the e-beam thickness of the coating beam would be in excess of the horizontal thickness so as to produce faster coatings and reduce the number of coating passes. Regarding claims 36 and 37, the claims recite up to 10 or 20 microns. Nishimura et al. (2005/0005892) teaches thickness of 0.5 microns [0102]-[0103], Rajagopalan et al. (2012/0178637) teaches a thickness of 0.01-10 microns [0078] and EP 3636795 teaches up to 1nm thickness [0033]. Regarding claims 34 and 38, Rajagopalan et al. (2012/0178637) teaches vickers hardness of 4500-6000 HV [0068]-[0070]. Response to Amendment Applicant's arguments filed 7/1/25 have been fully considered but they are not persuasive. Applicant argued the prior art teaches a single non-orthogonal coating beam as it teaches using less than 80 degrees and multiple coating beams. Wang et al. "The preparation and evaluation of graded multilayered ta-C films deposited by FCVA method" teaches this as detailed above. Any inquiry concerning this communication or earlier communications from the examiner should be directed to BRIAN K TALBOT whose telephone number is (571)272-1428. The examiner can normally be reached Monday -Friday 7-4PM. 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, MICHAEL CLEVELAND can be reached on 571-272-1418. 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. /BRIAN K TALBOT/ Primary Examiner, Art Unit 1712
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Prosecution Timeline

Apr 26, 2023
Application Filed
Jan 15, 2025
Non-Final Rejection — §103
Mar 27, 2025
Response Filed
Apr 10, 2025
Final Rejection — §103
May 07, 2025
Interview Requested
May 14, 2025
Applicant Interview (Telephonic)
May 14, 2025
Examiner Interview Summary
Jun 05, 2025
Response after Non-Final Action
Jul 01, 2025
Request for Continued Examination
Jul 03, 2025
Response after Non-Final Action
Jul 30, 2025
Non-Final Rejection — §103
Sep 17, 2025
Applicant Interview (Telephonic)
Sep 17, 2025
Examiner Interview Summary
Oct 06, 2025
Response Filed
Feb 17, 2026
Final Rejection — §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

5-6
Expected OA Rounds
59%
Grant Probability
90%
With Interview (+31.2%)
3y 4m
Median Time to Grant
High
PTA Risk
Based on 1151 resolved cases by this examiner. Grant probability derived from career allow rate.

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