Prosecution Insights
Last updated: April 17, 2026
Application No. 18/565,287

STIRLING ENGINE WITH NEAR ISOTHERMAL WORKING SPACES

Final Rejection §112
Filed
Nov 29, 2023
Examiner
HARRIS, WESLEY G
Art Unit
3783
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
unknown
OA Round
6 (Final)
73%
Grant Probability
Favorable
7-8
OA Rounds
2y 8m
To Grant
95%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allow Rate
509 granted / 697 resolved
+3.0% vs TC avg
Strong +22% interview lift
Without
With
+21.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
62 currently pending
Career history
759
Total Applications
across all art units

Statute-Specific Performance

§101
1.3%
-38.7% vs TC avg
§103
36.9%
-3.1% vs TC avg
§102
24.5%
-15.5% vs TC avg
§112
34.7%
-5.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 697 resolved cases

Office Action

§112
DETAILED ACTION The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . 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 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. Claim Objections Claim 19 is objected to because of the following informalities: lines 2-3 should be amended to -(a) a first piston cylinder assembly according to the piston cylinder assembly of claim 17; (b) a second piston cylinder assembly according to the piston cylinder assembly of claim 17;-. Lines 4-9 should be amended to - ( c) a first fluid flow path placing at least one through hole in [[a]] the head of the first piston cylinder assembly in fluid communication with at least one through hole in [[a]] the head of the second piston cylinder assembly; and ( d) a second fluid flow path placing at least one through hole in [[a]] the head of the second piston cylinder assembly in fluid communication with at least one through hole in [[a]] the head of the first piston cylinder assembly; -. Appropriate correction is required. Claim 22 is objected to because of the following informalities: lines 2-3 should be amended to - assembly being [[a]] the piston cylinder assembly according to claim 17;-. lines 2-3 should be amended to - (b) a first fluid flow path communicatively coupled between at least one through hole in [[a]] the head of the first piston cylinder assembly and at least one through hole in [[a]] the head of the second piston cylinder assembly; ( c) a second fluid flow path communicatively coupled between at least one through hole in [[a]] the head of the second piston cylinder assembly and at least one through hole in [[a]] the head of the third piston cylinder assembly; ( d) a third fluid flow path communicatively coupled between at least one through hole in [[a]] the head of the third piston cylinder assembly and at least one through hole in [[a]] the head of the fourth piston cylinder assembly; and ( e) a fourth fluid flow path communicatively coupled between at least one through hole in [[a]] the head of the fourth piston cylinder assembly and at least one through hole in [[a]] the head of the first piston cylinder assembly;-. Appropriate correction is required. Claim Rejections - 35 USC § 112 The following is a quotation of the first paragraph of 35 U.S.C. 112(a): (a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention. The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112: The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention. Claim 18 is rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. Regarding claim 18: The claim is rejected as new matter because of the limitation “wherein the internal surface of the head further comprises spiral-shaped fins that extend generally along a spiral path about the longitudinal axis…” in lines 1-8. This limitation refers to the embodiment shown in figure 12 while it depends on claim 17 which refers to the embodiment of figures 6-11. There is no indication in the original disclosure that these embodiments can be combined and further it’s not clear how they could be combined. For this reason, claim 18 is rejected as new matter. 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. Claims 17-24 are 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. Regarding claim 17: The term “approximate” in the line 22 of the claim are unclear. The term is ones of degree that suggest there is an acceptable range in regards to how equal the plow path of the lateral side of the head to the flow path of the central transverse valley. However the claims and specification fail to shed light on the range that acceptable suggests and for this reason the term and the claim is unclear. For the sake of examination, the office has assumed that the two flow paths should be equal. The applicant should amend the claim to clarify. Claims 18-24 are rejected due to their dependence on claim 17. Regarding claim 18: The term “approximate” in the line 4 of the claim are unclear. This term is unclear for the same reasons identified in the claim 17 rejection above. Regarding claim 19: The term “approximate” in the line 14 of the claim are unclear. This term is unclear for the same reasons identified in the claim 17 rejection above. The term “substantially” in the line 15 of the claim are unclear. This term is unclear for the same reasons identified for the term “approximate” in the claim 17 rejection above. Claims 20-21 are rejected due to their dependence on claim 19. Regarding claim 22: The term “approximate” in the line 20 of the claim are unclear. This term is unclear for the same reasons identified in the claim 17 rejection above. The term “substantially” in the line 21 of the claim are unclear. This term is unclear for the same reasons identified for the term “approximate” in the claim 17 rejection above. Claims 23-24 are rejected due to their dependence on claim 22. Allowable Subject Matter Claims 17 and 19-24 would be allowable if rewritten or amended to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action. Furthermore, the prior art of record does not teach “(d) a working fluid received in the internal bore between the piston crown and the head; wherein, on at least one lateral side of the head, the transverse valleys and transverse peaks follow a more tortuous path than the central transverse valley so as to increase a flow path length for the working fluid along the lateral side and to approximate a flow path length of the central transverse valley, such that flow path lengths for the working fluid through the central and lateral transverse valleys are more nearly equal during a longitudinal stroke of the piston, thereby providing more nearly uniform residence times and heat transfer characteristics across different flow regions of the head” as within the context of the claimed invention as disclosed and within the context of the other limitations present in claim 17. Therefore, the prior art of record cannot anticipate Applicant' s claimed invention by a single reference nor render Applicant' s claimed invention obvious by the combination of more than one reference. Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.” Response to Arguments Applicant’s arguments, see remarks, filed 12/12/25, with respect to non-final rejection filed 11/26/25 have been fully considered and are persuasive. Regarding the 35 USC 103 rejections of the claims: The applicant’s amendments to the claims have addressed the previous claim rejections and for this reason they are withdrawn. Regarding the 35 USC 112(b) and 112(a) rejections: The applicant’s amendments to the claims have addressed the previous claim rejections and for this reason they are withdrawn. The new set of rejections have been made based on the applicant’s amendments to the claims. Regarding the claim objections: The applicant’s amendments to the claims have addressed the previous claim objections and for this reason they are withdrawn. The new set of objections have been made based on the applicant’s amendments to the claims. 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 WESLEY HARRIS whose telephone number is (571)272-3665. The examiner can normally be reached M to F, 9am-5pm. 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 Tsai can be reached on (571) 270-5246. 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. /WESLEY G HARRIS/Examiner, Art Unit 3783
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Prosecution Timeline

Nov 29, 2023
Application Filed
Aug 02, 2024
Non-Final Rejection — §112
Oct 18, 2024
Response Filed
Jan 24, 2025
Final Rejection — §112
Mar 06, 2025
Response after Non-Final Action
Mar 21, 2025
Request for Continued Examination
Mar 24, 2025
Response after Non-Final Action
Mar 28, 2025
Non-Final Rejection — §112
May 16, 2025
Response Filed
Aug 08, 2025
Final Rejection — §112
Nov 04, 2025
Request for Continued Examination
Nov 13, 2025
Response after Non-Final Action
Nov 21, 2025
Non-Final Rejection — §112
Dec 12, 2025
Response Filed
Mar 19, 2026
Final Rejection — §112 (current)

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Prosecution Projections

7-8
Expected OA Rounds
73%
Grant Probability
95%
With Interview (+21.7%)
2y 8m
Median Time to Grant
High
PTA Risk
Based on 697 resolved cases by this examiner. Grant probability derived from career allow rate.

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