Prosecution Insights
Last updated: April 19, 2026
Application No. 18/682,929

PISTON RING

Non-Final OA §102§103§112§DP
Filed
Jul 21, 2025
Examiner
PATEL, VISHAL A
Art Unit
3675
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Ntn Corporation
OA Round
1 (Non-Final)
59%
Grant Probability
Moderate
1-2
OA Rounds
3y 1m
To Grant
81%
With Interview

Examiner Intelligence

Grants 59% of resolved cases
59%
Career Allow Rate
483 granted / 820 resolved
+6.9% vs TC avg
Strong +22% interview lift
Without
With
+21.7%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
47 currently pending
Career history
867
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
36.8%
-3.2% vs TC avg
§102
33.0%
-7.0% vs TC avg
§112
25.7%
-14.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 820 resolved cases

Office Action

§102 §103 §112 §DP
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 . Double Patenting The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969). A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b). The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13. The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer. Claims 1-11 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims of U.S. Patent application 18278175. Although the claims at issue are not identical, they are not patentably distinct from each other because the claims of 18278175 teach limitations of claim 1-11 of the current application (applicant should compare claims of 18278175 to current application). 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. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claim 6 is 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. Claim 6, entire claim, how can a piston ring now have structure of compressor that is a hydrogen gas compressor? 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) 1-2 and 4-11 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Kanei et al (US 20210156371A1). Kanei discloses a piston ring (e.g. 11 and/or 12) used in a reciprocating compressor that compresses gas, wherein the piston ring is formed of a resin composition (e.g. paragraph 0044-0053) containing at least polyetheretherketone resin or thermoplastic polyimide resin as a main component (e.g. see paragraph 0052), the resin composition contains carbon material (e.g. CF and see paragraph 0044) in which the content of sulfur atom is 200 ppm or less (e.g. see paragraph 0049), the carbon material is at least one of carbon fiber, graphite, and coke powder (e.g. paragraph 0044-0045, carbonfiller, carbon fibers and graphite) and the resin composition contains total 5-35 vol% of the carbon material relative to the whole of the resin composition (e.g. paragraph 0044-0053). Regarding claim 2: Wherein the resin composition contains 5-25 vol% of polytetrafluoroethylene resin relative to the whole of the resin composition (e.g. paragraph 0044, which states portion greater than additive which is 5-40% by mass and paragraph 0052 which teaches combination thereof). Regarding claim 3: Wherein the carbon material includes at least the carbon fiber (e.g. carbon fiber stated in the reference). Regarding claim 4: Wherein the content of the sulfur atom in the piston ring is 250 ppm or less (see paragraph 0049). Regarding claim 5: Wherein the resin composition contains the polyetheretherketone resin as a main component, and the piston ring has an endothermic peak due to heat hysteresis in a range of 150-330 °C in a temperature increasing process of the differential scanning calorimetry (e.g. this is the case since the material stated in the claims is taught by Kanei). Regarding claim 6: Wherein the reciprocating compressor is configured as a hydrogen gas reciprocating compressor that compresses hydrogen gas (e.g. the piston ring is used in compressor that is capable of having hydrogen gas). Regarding claim 7: Kanei discloses a piston ring used in a reciprocating compressor that compresses gas, wherein the piston ring is formed of a resin composition containing thermoplastic polyimide resin or polyamideimide resin as a main component (e.g. paragraph 0050-0052) and the content of a sulfur atom in the piston ring is less than 5 ppm (e.g. paragraph 0049). Regarding claim 8: Wherein the content of the sulfur atom in the piston ring is measured by a triple quadrupole inductively coupled plasma mass spectrometry (e.g. again how one measures the amount of sulfur atom is not patentable weight in an apparatus of a piston ring). It is noted that the sulfur atom in Kanei is capable of being measured by plasma mass spectrometry. Regarding claim 9: Wherein the resin composition does not contain carbon material and sulfide (e.g. see paragraph 0052 and paragraph 0045, it is noted that the resin composition does not contain both carbon material and sulfide). Regarding claim 10: Wherein the resin composition contains at least one of polytetrafluoroethylene resin and aromatic polyester resin (see paragraph 0052). Regarding claim 11: Wherein the resin composition contains the polytetrafluoroethylene resin and the aromatic polyester resin, and the total compound rate of the polytetrafluoroethylene resin and the aromatic polyester resin is 5-50 vol% relative to the whole of the resin composition (e.g. paragraph 0044, which states portion greater than additive which is 5-40% by mass and paragraph 0052 which teaches combination thereof). 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) 3 is rejected under 35 U.S.C. 103 as being unpatentable over Kanei in view of Oga et al (JP2022058162A). Kanei discloses the invention as claimed above but fails to disclose the carbon fiber having the average fiber length of the carbon fiber is 20-200 micrometer. Oga discloses a piston ring (e.g. figures) used in a reciprocating compressor that compresses gas, wherein the piston ring is formed of a resin composition and carbon fibers (e.g. see PEEK resin) containing at least polyetheretherketone resin or thermoplastic polyimide resin as a main component (e.g. see above), the resin composition contains carbon material (e.g. Oga states the carbon fibers and the filler fibers is about 200 micrometer). It would have been obvious to one skilled in the art before the effective filing date of the claimed invention to have the size of the carbon fibers in Kanei to be between 20-200 micrometer as taught by Oga with reasonable expectation of success to provide effective wear resistance (see Oga “The length of the filler fiber contained in the resin forming the seal ring 1 is preferably 1000 μm or less. If the length of the filler fiber exceeds 1000 μm, shrinkage anisotropy during injection molding becomes strong, which is not preferable. Further, it is desirable that the average length of the filler fibers is about 200 μm. The filler fiber is not limited to the above length, and may be any shape and size that can exhibit the effect of wear resistance. Further, although carbon fiber is exemplified as the filler fiber, the present invention is not limited to carbon fiber, and may be, for example, glass fiber or CNF (cellulose nanofiber)”). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Applicant should review document US20200408302 which teach all the limitation of the claims, document US20200340582 teach all the limitations of the claims, reference JP2013155846 teach the limitation of the claims, US20020168506 teaches limitations of claim, paragraph 0049 and JPH02175793. Any inquiry concerning this communication or earlier communications from the examiner should be directed to VISHAL A PATEL whose telephone number is (571)272-7060. The examiner can normally be reached 7:00 am to 4:00pm. 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. /VISHAL A PATEL/Primary Examiner, Art Unit 3675
Read full office action

Prosecution Timeline

Jul 21, 2025
Application Filed
Jan 23, 2026
Non-Final Rejection — §102, §103, §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12601404
Internally clamping rectangular seal
2y 5m to grant Granted Apr 14, 2026
Patent 12590634
Piston Seal Ring Bypass
2y 5m to grant Granted Mar 31, 2026
Patent 12584556
SLIDING MEMBER
2y 5m to grant Granted Mar 24, 2026
Patent 12569962
HIGH PRESSURE LIQUID-JET SEAL ASSEMBLY CARRIAGE
2y 5m to grant Granted Mar 10, 2026
Patent 12560239
SLIDING COMPONENTS
2y 5m to grant Granted Feb 24, 2026
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
59%
Grant Probability
81%
With Interview (+21.7%)
3y 1m
Median Time to Grant
Low
PTA Risk
Based on 820 resolved cases by this examiner. Grant probability derived from career allow rate.

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