Office Action Predictor
Last updated: April 16, 2026
Application No. 18/927,055

LIQUID HYDROGEN PUMP IMPELLOR ASSEMBLY

Non-Final OA §112
Filed
Oct 25, 2024
Examiner
CLARK, RYAN C
Art Unit
3745
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Rolls-Royce PLC
OA Round
3 (Non-Final)
87%
Grant Probability
Favorable
3-4
OA Rounds
1y 10m
To Grant
91%
With Interview

Examiner Intelligence

Grants 87% — above average
87%
Career Allow Rate
231 granted / 265 resolved
+17.2% vs TC avg
Minimal +4% lift
Without
With
+4.2%
Interview Lift
resolved cases with interview
Fast prosecutor
1y 10m
Avg Prosecution
37 currently pending
Career history
302
Total Applications
across all art units

Statute-Specific Performance

§101
2.7%
-37.3% vs TC avg
§103
38.6%
-1.4% vs TC avg
§102
30.7%
-9.3% vs TC avg
§112
26.3%
-13.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 265 resolved cases

Office Action

§112
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 . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 12/18/2025 has been entered. Response to Arguments Applicant’s arguments with respect to claims 3 and 10 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. 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. Claims 3, 10, and 13 are 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. Claim 3 recites, “The impellor assembly according to claim 2, wherein the coefficient of thermal expansion of the first material is higher than that of the second material, and wherein the coefficient of thermal expansion of the first material is within 25% of two times the coefficient of thermal expansion of the second material.” The Examiner respectfully notes the immediate Specification only has definite support for “two times that of the second material” (Pg.2: 27-30 and Pg.8:27-30) as substantially and approximately are undefined in the immediate disclose (see Non-Final Rejection 04/23/2025 Pg.2-3, Final Rejection 09/23/2025 Pg.4-5). Additionally, there appears to be no recitation or indication of “the coefficient of thermal expansion of the first material is within 25% of two times the coefficient of thermal expansion of the second material” in the immediate Specification, or the original claims; and therefore was not described in the specification in such a way as to reasonably convey to one skilled in the art. Claim 10 recites, “The impellor assembly according to claim 9, wherein the bearing arrangement comprises a bearing mounted to a bearing race, the bearing race comprising a material, the coefficient of thermal expansion of the bearing race material being within 15% of the coefficient of thermal expansion of the material of the shaft.” The Examiner respectfully notes the immediate Specification only has definite support for “a material having the same coefficient of thermal expansion as the material of the shaft” (Pg. 3:13-17) as substantially and approximately are undefined in the immediate disclose (see Non-Final Rejection 04/23/2025 Pg.3, Final Rejection 09/23/2025 Pg.5). Additionally, there appears to be no recitation or indication of “the coefficient of thermal expansion of the bearing race material being within 15% of the coefficient of thermal expansion of the material of the shaft” in the immediate Specification, or the original claims; and therefore was not described in the specification in such a way as to reasonably convey to one skilled in the art. Claim 13 is rejected based on its dependency. Allowable Subject Matter Claims 1-2, 4-9, 11-12, and 14-20 are allowed. PNG media_image1.png 364 506 media_image1.png Greyscale Regarding claim 1, Kunzelmann (DE 10 2016 119 233 A1) discloses an impellor assembly (Fig. 1) for a liquid hydrogen pump (the Examiner notes that the impeller disclosed in Kunzelmann would be fully capable of being used in a liquid hydrogen pump and there for is “for a liquid hydrogen pump”), the assembly comprising: a shaft (2); one or more impellors (4) mounted to the shaft; a fastener (5) configured to engage with the shaft at a first engagement point (10,11) and with the one or more impellor at a second engagement point (near 5 on the impeller, it is affixed to the shaft through the head and the threads) to axially clamp the one or more impellor to the shaft (Fig. 1), and axially unconstrained length (6, 8) of the fastener being defined by an axial distance between the first and second engagement points (Fig. 1) wherein; an axial extent (6) of a clamped portion of the one or more impellors corresponds to the axially unconstrained length of the fastener (Fig. 1); and the fastener and the impellor comprise a material (aluminum, [0025]) having a first coefficient of thermal expansion and the shaft comprises a material (steel, [0025]) having a second coefficient of thermal expansion wherein the first and second coefficients of thermal expansion are different ([0025], “both materials have different coefficients of expansion.” However; Kunzelmann nor any of the prior art of record disclose, teach, or suggest; “and wherein the axial distance is within 20% of the axial extent” and Kunzelmann is completely silent on the ratio between the length of the fastener and the length of the impeller portion. Claims 2, 4-9, 11-12, and 14-20 are allowable based on their dependencies. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to RYAN C CLARK whose telephone number is (571)272-2871. The examiner can normally be reached Monday - Thursday 0730-1730, Alternate Fridays 0730-1630. 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, Courtney D Heinle can be reached at (571)-270-3508. 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. /RYAN C CLARK/Examiner, Art Unit 3745
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Prosecution Timeline

Oct 25, 2024
Application Filed
Apr 18, 2025
Non-Final Rejection — §112
Jul 14, 2025
Response Filed
Sep 18, 2025
Final Rejection — §112
Oct 30, 2025
Interview Requested
Nov 21, 2025
Response after Non-Final Action
Dec 18, 2025
Request for Continued Examination
Jan 19, 2026
Response after Non-Final Action
Jan 29, 2026
Non-Final Rejection — §112
Apr 01, 2026
Response Filed

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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
87%
Grant Probability
91%
With Interview (+4.2%)
1y 10m
Median Time to Grant
High
PTA Risk
Based on 265 resolved cases by this examiner. Grant probability derived from career allow rate.

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