Prosecution Insights
Last updated: October 04, 2026
Application No. 18/283,151

Compression Ring

Final Rejection §103
Filed
Aug 30, 2024
Priority
Sep 08, 2022 — nonprovisional of PCTJP2022033776
Examiner
PATEL, VISHAL A
Art Unit
3675
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Tpr Co. Ltd.
OA Round
4 (Final)
59%
Grant Probability
Moderate
5-6
OA Rounds
12m
Est. Remaining
82%
With Interview

Examiner Intelligence

Grants 59% of resolved cases
59%
Career Allowance Rate
491 granted / 832 resolved
+7.0% vs TC avg
Strong +22% interview lift
Without
With
+22.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
52 currently pending
Career history
884
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
39.2%
-0.8% vs TC avg
§102
31.3%
-8.7% vs TC avg
§112
25.9%
-14.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 832 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 . Response to Arguments Applicants’ arguments filed 9/8/2026 have been fully considered but they are not persuasive and/or moot in view of new rejections. Applicants’ argument that the reference of Tamaki does not teach the material of the ring and the coating recited in amended claim 1 is not persuasive since the material of the ring and the coating is well known and old, see rejections below. Applicants’ argument that the reference of Nango does not teach the material of the ring and the coating recited in amended claim 1 is not persuasive since the material of the ring and the coating is well known and old, see rejections below. 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) 1 is rejected under 35 U.S.C. 103 as being unpatentable over Tamaki (JP2021001612A) in view of Kawano et al (US20190360585A1). Tamaki discloses a compression ring (figure 3) to be used in a spark-ignition engine using hydrogen gas fuel and to be fitted to a piston ring groove of a piston installed in a cylinder (e.g. intended use the compression ring of Tamaki is capable of being used in the environment as claimed), wherein an outer periphery shape of the compression ring is a barrel shape (e.g. barrel shape having 131) or an eccentric barrel shape (e.g. figure 3), an abrasion value T of the outer periphery of the compression ring is less than or equal to 10 (e.g. again since the structure of barrel shape is provided Tamaki this limitation is met), wherein the abrasion value T is determined by an abrasion resistance test performed with a reciprocating friction tester under the abrasion resistance test conditions to evaluate an outer peripheral sliding surface of the compression ring (e.g. the compression ring of Tamaki is capable of being tested as defined hereto), TW1 is an amount of abrasion of the outer peripheral sliding surface in the test with dropping of 1 mL/hour of a bearing oil and 0.5 mL/hour of distilled water (e.g. again the compression ring of Tamaki is capable in condition defined hereto), TO1 (um) is as an amount of abrasion of the outer peripheral sliding surface in the test with dropping of only 1 mL/hour of the bearing oil and no distilled water (e.g. again the compression ring of Tamaki is capable in condition defined hereto), and T (um) = TW1 - TO1 (e.g. it is inherent that when one skilled in the art performs first abrasion test where an element is subjected to mixture of oil and water and a second abrasion test where the same element is subjected to only oil, the following T is going to be defined ); and A/T > 100 is satisfied, wherein A(HVO.1) is a surface Vickers hardness of the outer peripheral sliding surface (e.g. the structure of the barrel shape is defined so A/T is going to be as stated and furthermore it is noted that applicant has not provided any particular hardness structure such as material of ring or coating or etc), an abrasion index M of the outer periphery of the compression ring is less than or equal to 0.09 (e.g. M is also going to be defined since the only structure claimed is the barrel shaped which is taught by Tamaki), wherein Ft (N) is defined as a tension of the compression ring (e.g. as seen in figures 1-3 to Tamaki, the compression ring is capable of being in tension by fluid from cylinder assembly shown in figure 1), S13 (mm) is defined as a length (e.g. S11, figure 3) in an axis direction of the outer peripheral sliding surface of the compression ring (e.g. see S11 in figure 3 of Tamaki), and in a case where the piston is disposed so that the outer periphery of the compression ring abuts with a cylinder bore (e.g. the compression ring of Tamaki is capable of contacting a cylinder, see figure 1), D (mm) is defined as an inner diameter of the cylinder bore (e.g. figure 1 shows that a cylinder has an inner diameter where the compression ring is capable of contacting), a11 (mm) is defined as a distance (e.g. a11, figure 3 of Tamaki) in a radius direction between an upper connection point of the compression ring and an inner wall of the cylinder bore (e.g. figure 1 and 3), a12 (mm) is defined as a distance (e.g. a12, figure 3 of Tamaki) in a radius direction between a lower connection point of the compression ring and the inner wall of the cylinder bore (see figures 1 and 3), and Fd = Ft/D, head h = (a11 + a12)/2 (e.g. this is taught by Tamaki, see a11 and a12 in figure 3), outer periphery inclination OSt = h/(S13/2), and the abrasion index M = T x Fd x Ost (e.g. this is also possible since the structure of compression ring with a particular barrel shape is taught, a11, a12 and s11, see figure 3), wherein the abrasion resistance test conditions are as follows: - Stroke: 50 mm - Load: 100 N - Speed: 600 cycles/min - Temperature control of upper test piece: room temperature - Temperature control of lower test piece: room temperature - Bearing oil: Shell Tetra Oil 2SP, Shell Lubricants Japan K.K. - Dropping conditions of bearing oil: dropping once every one minute and controlling the total amount of dropping to 1 mL/hour - Dropping conditions of distilled water: dropping once every one minute and controlling the total amount of dropping to 0.5 mL/hour - Test time: 60 minutes - The test is performed after the trial run is performed under the following conditions. - Load: 20 N - Speed: 100 cycles/min - Temperature of upper test piece before test: room temperature - Temperature of lower test piece before test: room temperature - Bearing oil: Shell Tetra Oil 2SP, Shell Lubricants Japan K.K. - Dropping conditions of bearing oil: dropping once every one minute and controlling the total amount of dropping to 0.08 mL/5 min, and - Test time: 5 minutes (The italicized limitations recite product-by-process limitations. Even 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 associated methods, only the end result. See MPEP 2113. Since Tamaki teaches a compression ring with a barrel shape, the end result is the same regardless of the method used to test the product). PNG media_image1.png 412 575 media_image1.png Greyscale Tamaki discloses the invention as claimed above but fails to disclose the piston ring is high-alloy or low-alloy steel and a coating of the compression ring includes at least one selected from the group consisting of PVD coating and DLC coating. Takiguchi discloses piston rings made of steel (e.g. paragraph 0051, steel) with an outer surface that is coated with DLC coating or PVD coating (e.g. paragraph 0029) with a thickness that is 0.5 mm or less (e.g. paragraph 0029).. It would have been obvious to one skilled in the art before the effective filing date of the claimed invention to have the piston ring of Tamaki be made of alloy steel and a coating (e.g. ) thereon as taught by Takiguchi, with reasonable expectation of success to reduce wear (e.g. see entire document and especially paragraph 0029) and provide sufficient strength to the piston ring (e.g. inherent due to steel and applicant has not stated any particular steel). Claim(s) 1 is rejected under 35 U.S.C. 103 as being unpatentable over Tamaki (JP2021001612A) in view of JP5833276B1. Tamaki discloses the invention as claimed above but fails to disclose the piston ring is high-alloy or low-alloy steel and a coating of the compression ring includes at least one selected from the group consisting of PVD coating, DLC coating, hard chrome plating coating and nitride coating. JP5833276 discloses piston rings made of steel (see description of 10) with a coating including at least one of a DLC coating and PVD coating. (e.g. (6-5) DLC (amorphous carbon) coating by an ion plating method using only carbon. (6-6) A DLC (amorphous carbon) film formed by an ion plating method containing one or more elements of silicon, oxygen, hydrogen, tungsten, and titanium in addition to carbon. (6-7) Either (6-5) or (6-6) DLC film is applied to the outer periphery of any one of the hard films of the above-mentioned nitride films (6-1) to (6-4). A coating composed of a coating. Moreover, among the above-mentioned hard coatings 11a and 12a, each surface hardness from (6-1) to (6-7) is HV1000 or more, and each from (6-1) to (6-6). The thickness of the coating is 3 μm, and the thickness of the multilayer of (6-7) is 3 μm or more., see JP5833276). It would have been obvious to one skilled in the art before the effective filing date of the claimed invention to have the piston ring of Tamaki be made of alloy steel and a coating thereon as taught by JP5833276, with reasonable expectation of success to reduce wear (e.g. coatings PVD layer or DLC layer, see paragraph 0052 of Chiba) and provide sufficient durability to the piston ring (e.g. since the ring is made of steel). Claim(s) 1 is rejected under 35 U.S.C. 103 as being unpatentable over Nango (US202110164568A1) in view of Ikeya et al (WO. 2020095807A1). Nango discloses a compression ring (figures 3 and 4) to be used in a spark-ignition engine using hydrogen gas fuel and to be fitted to a piston ring groove of a piston installed in a cylinder (e.g. intended use the compression ring of Nango is capable of being used in the environment as claimed), wherein an outer periphery shape of the compression ring is a barrel shape (e.g. barrel shape having 131) or an eccentric barrel shape (e.g. figures 3 and 4), an abrasion value T of the outer periphery of the compression ring is less than or equal to 10 (e.g. again since the structure of barrel shape is provided Nango this limitation is met), wherein the abrasion value T is determined by an abrasion resistance test performed with a reciprocating friction tester under the abrasion resistance test conditions to evaluate an outer peripheral sliding surface of the compression ring (e.g. the compression ring of Nango is capable of being tested as defined hereto), TW1 is an amount of abrasion of the outer peripheral sliding surface in the test with dropping of 1 mL/hour of a bearing oil and 0.5 mL/hour of distilled water (e.g. again the compression ring of Nango is capable in condition defined hereto), TO1 (um) is as an amount of abrasion of the outer peripheral sliding surface in the test with dropping of only 1 mL/hour of the bearing oil and no distilled water (e.g. again the compression ring of Nango is capable in condition defined hereto), and T (um) = TW1 - TO1 (e.g. it is inherent that when one skilled in the art performs first abrasion test where an element is subjected to mixture of oil and water and a second abrasion test where the same element is subjected to only oil, the following T is going to be defined ), and A/T > 100 is satisfied, wherein A(HVO.1) is a surface Vickers hardness of the outer peripheral sliding surface (e.g. the structure of the barrel shape is defined so A/T is going to be as stated and furthermore it is noted that applicant has not provided any particular hardness structure such as material of ring or coating or etc), an abrasion index M of the outer periphery of the compression ring is less than or equal to 0.09 (e.g. M is also going to be defined since the only structure claimed is the barrel shaped which is taught by Nango), wherein Ft (N) is defined as a tension of the compression ring (e.g. as seen in figures 1-4 to Nango and the compression ring is capable of being in tension by fluid from cylinder assembly shown in figure 1), S13 (mm) is defined as a length (e.g. S11, figures 3 and 4) in an axis direction of the outer peripheral sliding surface of the compression ring (e.g. see S11 in figures 3-4 of Nango), and in a case where the piston is disposed so that the outer periphery of the compression ring abuts with a cylinder bore (e.g. the compression ring of Nango is capable of contacting a cylinder, see figure 1), D (mm) is defined as an inner diameter of the cylinder bore (e.g. figure 1 shows that a cylinder has an inner diameter where the compression ring is capable of contacting), a11 (mm) is defined as a distance (e.g. a11, figures 3-4 of Nango) in a radius direction between an upper connection point of the compression ring and an inner wall of the cylinder bore (e.g. figure 1 and 3), a12 (mm) is defined as a distance (e.g. a12, figures 3-4 of Nango) in a radius direction between a lower connection point of the compression ring and the inner wall of the cylinder bore (see figures 1 and 3), and Fd = Ft/D, head h = (a11 + a12)/2 (e.g. this is taught by Nango, see a11 and a12 in figure 3), outer periphery inclination OSt = h/(S13/2), and the abrasion index M = T x Fd x Ost (e.g. this is also possible since the structure of compression ring with a particular barrel shape is taught, a11, a12 and s11, see figure 3), wherein the abrasion resistance test conditions are as follows: - Stroke: 50 mm - Load: 100 N - Speed: 600 cycles/min - Temperature control of upper test piece: room temperature - Temperature control of lower test piece: room temperature - Bearing oil: Shell Tetra Oil 2SP, Shell Lubricants Japan K.K. - Dropping conditions of bearing oil: dropping once every one minute and controlling the total amount of dropping to 1 mL/hour - Dropping conditions of distilled water: dropping once every one minute and controlling the total amount of dropping to 0.5 mL/hour - Test time: 60 minutes - The test is performed after the trial run is performed under the following conditions. - Load: 20 N - Speed: 100 cycles/min - Temperature of upper test piece before test: room temperature - Temperature of lower test piece before test: room temperature - Bearing oil: Shell Tetra Oil 2SP, Shell Lubricants Japan K.K. - Dropping conditions of bearing oil: dropping once every one minute and controlling the total amount of dropping to 0.08 mL/5 min, and - Test time: 5 minutes (The italicized limitations recite product-by-process limitations. Even 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 associated methods, only the end result. See MPEP 2113. Since Nango teaches a compression ring with a barrel shape in figures 3-4, the end result is the same regardless of the method used to test the product). PNG media_image2.png 460 565 media_image2.png Greyscale PNG media_image3.png 500 544 media_image3.png Greyscale Nango discloses the invention as claimed above but fails to disclose the piston ring is high-alloy or low-alloy steel and a coating of the compression ring includes at least one selected from the group consisting of PVD coating and DLC coating. Sytsma discloses piston rings made of stainless steel or alloy steel with an outer surface (e.g. see “A steel material equivalent to SUS440 (JIS standard) which is martensitic stainless steel is used for the first pressure ring exposed to a harsh environment. On the other hand, a stainless steel material containing about 9 to 14% by mass of Cr is used for the second pressure ring having a small heat load and pressure load.”) having a coating selected from one of PVD coating and DLC coating (e.g. see hydrogen free DLC coating as stated in example 2-7) with thickness of 0.5mm or less (see description of hard carbon film having thickness of 0.5 micro meter or more). It would have been obvious to one skilled in the art before the effective filing date of the claimed invention to have the piston ring of Nango be made of alloy steel and a coating thereon as taught by Ikeya, with reasonable expectation of success to reduce wear (e.g. coatings that are PVD layer or DLC layer, see Ikeya) and provide sufficient durability to the piston ring (e.g. inherent due to steel or stainless steel, see Ikeya). Conclusion 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 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
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Prosecution Timeline

Show 5 earlier events
Sep 11, 2025
Examiner Interview Summary
Oct 21, 2025
Response Filed
Nov 05, 2025
Final Rejection mailed — §103
Jan 22, 2026
Request for Continued Examination
Feb 03, 2026
Response after Non-Final Action
Jul 02, 2026
Non-Final Rejection mailed — §103
Sep 08, 2026
Response Filed
Sep 21, 2026
Final Rejection mailed — §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
82%
With Interview (+22.5%)
3y 1m (~12m remaining)
Median Time to Grant
High
PTA Risk
Based on 832 resolved cases by this examiner. Grant probability derived from career allowance rate.

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