Prosecution Insights
Last updated: April 19, 2026
Application No. 18/988,853

PISTON RING WITH TRAPEZOIDAL OPENING

Final Rejection §102§Other
Filed
Dec 19, 2024
Examiner
LEE, GILBERT Y
Art Unit
3675
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Mahle International GmbH
OA Round
2 (Final)
79%
Grant Probability
Favorable
3-4
OA Rounds
2y 6m
To Grant
89%
With Interview

Examiner Intelligence

Grants 79% — above average
79%
Career Allow Rate
1081 granted / 1376 resolved
+26.6% vs TC avg
Moderate +10% lift
Without
With
+10.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
44 currently pending
Career history
1420
Total Applications
across all art units

Statute-Specific Performance

§101
0.2%
-39.8% vs TC avg
§103
44.3%
+4.3% vs TC avg
§102
36.9%
-3.1% vs TC avg
§112
13.7%
-26.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1376 resolved cases

Office Action

§102 §Other
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 amendment filed 11/26/25 has been entered. 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. Claim(s) 1-20 is/are rejected under 35 U.S.C. 102a1 as being anticipated by Sawashita (JP2016061407A). Regarding claim 1, the Sawashita reference discloses a piston ring (10) for use in a piston ring groove (Fig. 6a) of a piston, the piston ring comprising: a piston ring main body (body of 10) with an opening (20); at least one trapezoidal boss (61d) disposed at one end of the opening on the piston ring main body; and at least one groove (62c) disposed at other end of the opening on the piston ring main body, the groove being shaped to correspond with the trapezoidal boss (Fig. 5a) and including a first wall (e.g. wall at 61d), a second wall (e.g. wall opposite 61d), and an inner side (e.g. right side of 61d) between the first and second walls (Fig. 5a); wherein the trapezoidal boss has a width that decreases toward the inner side (Fig. 5a); wherein a height of the trapezoidal boss is not greater than a depth of the groove (Fig. 5a); and wherein the piston ring main body has a first width on one side of the opening that is different from a second width on the opposite side of the opening (Fig. 5a), such that during engine operation, only one side surface of the trapezoidal boss contacts a corresponding side surface of the groove (e.g. Fig. 3a). Regarding claims 2 and 12, the Sawashita reference discloses a width of the piston ring main body is at a minimum at a position adjacent to the opening and increases linearly to a full width of the piston ring main body at a position corresponding to an arc length between 60° and 180° (e.g. 10a, Fig. 1a), measured from the position adjacent to the opening or an arc length between -60° and -180°, measured from the position adjacent to the opening (e.g. 10a, Fig. 1a). Regarding claims 3 and 13, the Sawashita reference discloses a width of the piston ring main body adjacent to the trapezoidal boss is less than a width of the piston ring main body adjacent to the groove (Fig. 5a). Regarding claims 4 and 14, the Sawashita reference discloses a top surface of the piston ring main body adjacent to a side of a combustion chamber is a flat surface, and the width of the piston ring main body increases linearly from a lower surface of the piston ring main body adjacent to the trapezoidal boss to a position of the top surface corresponding to an arc length between 60° and 150°, measured from the lower surface adjacent to the trapezoidal boss (e.g. 10a, Fig. 1a). Regarding claims 5 and 15, the Sawashita reference discloses the width of the piston ring main body increases linearly from the lower surface of the piston ring main body adjacent to the trapezoidal boss to a position of the top surface corresponding to an arc length of 90°, measured from the lower surface adjacent to the trapezoidal boss (Fig. 1a). Regarding claims 6 and 16, the Sawashita reference discloses a width of the piston ring main body adjacent to the groove is less than a width of the piston ring main body adjacent to the trapezoidal boss (Fig. 5a). Regarding claims 7 and 17, the Sawashita reference discloses a top surface of the piston ring main body adjacent to a side of a combustion chamber is a flat surface, and the width of the piston ring main body increases linearly from a lower surface of the piston ring main body adjacent to the groove to a position of the top surface corresponding to an arc length between -60° and -150°, measured from the lower surface adjacent to the groove (e.g. 10a, Fig. 1a). Regarding claims 8 and 18, the Sawashita reference discloses the width of the piston ring main body increases linearly from the lower surface of the piston ring main body adjacent to the groove to a position of the top surface corresponding to an arc length of -90°, measured from the lower surface of the piston ring main body adjacent to the groove (Fig. 1a). Regarding claims 9 and 19, the Sawashita reference discloses a width of the trapezoidal boss is at least half of the full width of the piston ring main body (Fig. 5a). Regarding claims 10 and 20, the Sawashita reference discloses a gradual bottom surface portion of the piston ring main body (Fig. 5a).MPEP 2113 Product-by-Process Claims states that "If the product in the product-by-process claim is that same as or obvious from a product of the prior art, the claim is unpatentable even though the prior art product was made by a different process." Claims 10 and 20 are anticipated by Sawashita. The process by which the bottom surface is made is not a patentable distinction. Regarding claim 11, the Sawashita reference discloses a piston ring (10) for use in a piston ring groove (Fig. 6a) of a piston, the piston ring comprising: a piston ring main body (body of 10) with an opening (20); at least one trapezoidal boss (61d) disposed at one end of the opening on the piston ring main body; and at least one trapezoidal recess (62c) disposed at other end of the opening on the piston ring main body, the trapezoidal recess being shaped to correspond with the trapezoidal protrusion (Fig. 5a) and including a first wall (e.g. wall at 61d), a second wall (e.g. wall opposite 61d), and an inner side (e.g. right side of 61d) between the first and second walls (Fig. 5a); wherein the trapezoidal boss has a width that decreases toward the inner side (Fig. 5a); wherein a height of the trapezoidal protrusion is not greater than a depth of the trapezoidal recess; and wherein a height of the trapezoidal boss is not greater than a depth of the groove (Fig. 5a); and wherein the piston ring main body has a first width on one side of the opening that is different from a second width on the opposite side of the opening (Fig. 5a), such that during engine operation, only one side surface of the trapezoidal boss contacts a corresponding side surface of the groove (e.g. Fig. 3a). Response to Arguments Applicant's arguments filed 11/26/25 have been fully considered but they are not persuasive. With regards to the applicant’s argument of the amended claims, the argument is not persuasive because claims do not preclude the “right side” of 61d in Fig. 5a from being interpreted as the “inner side”. Conclusion THIS ACTION IS MADE FINAL. 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 GILBERT Y LEE whose telephone number is (571)272-5894. The examiner can normally be reached Monday-Friday 8am-430pm. 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, Christine Mills can be reached at (571)272-8322. 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. /GILBERT Y LEE/Primary Examiner, Art Unit 3675
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Prosecution Timeline

Dec 19, 2024
Application Filed
Aug 23, 2025
Non-Final Rejection — §102, §Other
Nov 26, 2025
Response Filed
Mar 06, 2026
Final Rejection — §102, §Other (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

3-4
Expected OA Rounds
79%
Grant Probability
89%
With Interview (+10.4%)
2y 6m
Median Time to Grant
Moderate
PTA Risk
Based on 1376 resolved cases by this examiner. Grant probability derived from career allow rate.

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