Prosecution Insights
Last updated: April 19, 2026
Application No. 18/386,819

HEAT EXCHANGER WITH STIFFENING TUBE CONNECTORS

Non-Final OA §102§103
Filed
Nov 03, 2023
Examiner
RUPPERT, ERIC S
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Hamilton Sundstrand Corporation
OA Round
1 (Non-Final)
59%
Grant Probability
Moderate
1-2
OA Rounds
2y 10m
To Grant
83%
With Interview

Examiner Intelligence

Grants 59% of resolved cases
59%
Career Allow Rate
437 granted / 739 resolved
-10.9% vs TC avg
Strong +24% interview lift
Without
With
+24.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
55 currently pending
Career history
794
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
48.5%
+8.5% vs TC avg
§102
21.1%
-18.9% vs TC avg
§112
27.3%
-12.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 739 resolved cases

Office Action

§102 §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 . Election/Restrictions Applicant’s election of Species A in the reply filed on 2/19/2026 is acknowledged. Because applicant did not distinctly and specifically point out the supposed errors in the restriction requirement, the election has been treated as an election without traverse (MPEP § 818.01(a)). Claim 6 is withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 2/19/2026. 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) 1-8 and 17-19 is/are rejected under 35 U.S.C. 102 (a) (1) as being anticipated by Kusuda (US20140251585A1). Regarding claim 1, Kusuda discloses a heat exchanger (see Fig. 3-5), comprising: an upstream header (manifold 524); a downstream header (manifold 534); a core (body 514) extending from an upstream end at the upstream header to a downstream end at the downstream header, wherein the core includes tubes arranged in a square matrix (see shape in Fig. 3-4) that defines rows of tubes (302/314, 546/544) arranged in a row direction and columns of the tubes arranged in a column direction that is normal to the row direction, each of the tubes defining an upstream end and a downstream end that are spaced apart from each other in a longitudinal direction (see tubes upstream and downstream of each node 302/314, 516/530), and an outer boundary of the core is defined by outer ones of the tubes, wherein each of the tubes is longitudinally divided into tube segments; and tube connectors (node 302/314, 516/530) extending between the tube segments and interconnecting longitudinally and diagonally adjacent ones of the tube segments to stiffen the core (see angle of truss elements in Fig. 4). Regarding claim 2, Kusuda discloses the limitations of claim 1, and Kusuda further discloses the tube connectors (node 302/314, 516/530) extend longitudinally from a connector upstream end to a connector downstream end, each having: upstream ports at the upstream end; downstream ports at the downstream end; and a longitudinal center having an outer shell, wherein the outer shell defines therein flow paths between the upstream ports and the downstream ports. Regarding claim 3, Kusuda discloses the limitations of claim 2, and Kusuda further discloses an outer boundary of the tube connectors (node 302/314, 516/530) converges at the longitudinal center and diverges toward the upstream and downstream ends. Regarding claim 4, Kusuda discloses the limitations of claim 3, and Kusuda further discloses the tube connectors (node 302/314, 516/530) include four of the upstream ports, four of the downstream ports, and four of the flow paths within the outer shell. Regarding claim 5, Kusuda discloses the limitations of claim 4, and Kusuda further discloses each of the tube connectors (node 302/314, 516/530) has a mixing chamber (see hollow interior thereof) defined within the outer shell, intermediate of the upstream ends and the downstream ends, and the flow paths are fluidly coupled to each other at the mixing chamber. Regarding claim 7, Kusuda discloses the limitations of claim 4, and Kusuda further discloses each of the tubes is longitudinally divided into an upstream segment, a downstream segment, and an intermediate segment therebetween; the tube connectors include a first upstream set of the tube connectors is that longitudinally between and connects the upstream segment and the intermediate segment of the tubes; and the tube connectors include a first downstream set of the tube connectors that is longitudinally between and connects the downstream segment and the intermediate segment of the tubes (See annotated Fig. 5 below) PNG media_image1.png 683 602 media_image1.png Greyscale Annotated Fig. 5 of Kusuda Regarding claim 8, Kusuda discloses the limitations of claim 7, and Kusuda further discloses the core has a rectangular cross section (see shape of Fig. 3), and the outer boundary defines rectangular outer core faces that define outer core corners of the core (corners of 300), including: first and second outer core faces that are opposite each other and extend longitudinally from the upstream header to the downstream header and along the row direction; and third and fourth outer core faces that are opposite each other and extend longitudinally from the upstream header to the downstream header and along the column direction that is normal to the row direction. Regarding claim 17, Kusuda discloses the limitations of claim 1, and Kusuda further discloses every other column of the tubes is offset along the column direction by a distance that is at least a diameter of the tubes (see Fig. 3-5). Regarding claim 18, Kusuda discloses the limitations of claim 1, and Kusuda further discloses the tubes have a circular or oval cross section (circular, elliptical - ¶[0032]). Regarding claim 19, Kusuda discloses the limitations of claim 1, and Kusuda further discloses the tubes are longitudinally divided so that adjacent ones of the tube connectors in the row direction and the column direction within each of the upstream, downstream and intermediate segments are longitudinally offset from each other (see longitudinal, sequential sets of nodes 302/314, 516/530). 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) 116 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kusuda (US20140251585A1) in view of Becene (US20200284532A1). Regarding claim 16, Kusuda teaches the limitations of claim 3, and Kusuda does not teach the upstream header forms an upstream header trunk that subdivides along the longitudinal direction into upstream header branches that are fluidly coupled to the upstream end of the tubes; and the downstream header forms a downstream header trunk that subdivides along the longitudinal direction into downstream header branches that are fluidly coupled to the downstream ends of the tubes. Becene teaches the upstream header (branched header Fig. 3 & “inlet and outlet headers” - ¶[0009]) forms an upstream header trunk that subdivides along the longitudinal direction into upstream header branches that are fluidly coupled to the upstream end of the tubes; and the downstream header forms a downstream header (branched header Fig. 3) trunk that subdivides along the longitudinal direction into downstream header branches that are fluidly coupled to the downstream ends of the tubes. Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Kusuda to include the headers of Becene, in order to provide improved thermal and mechanical properties (¶[0009]). Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kusuda (US20140251585A1) in view of Becker (US20220260316A1). Regarding claim 20, Kusuda teaches the limitations of claim 1, and Kusuda does not teach the core is formed by additive manufacturing. Becker teaches the core is formed by additive manufacturing (¶[0075]). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Kusuda to include the additive manufacturing of Becker, in order to provide a single piece build, reducing the need for secondary machining or joining processes (¶[0075]). Allowable Subject Matter Claims 9-15 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERIC S RUPPERT whose telephone number is (571)272-9911. The examiner can normally be reached Monday - Friday 8 am - 4 pm. 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, Len Tran can be reached at 571-272-1184. 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. /ERIC S RUPPERT/Primary Examiner, Art Unit 3763
Read full office action

Prosecution Timeline

Nov 03, 2023
Application Filed
Mar 19, 2026
Non-Final Rejection — §102, §103 (current)

Precedent Cases

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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
83%
With Interview (+24.1%)
2y 10m
Median Time to Grant
Low
PTA Risk
Based on 739 resolved cases by this examiner. Grant probability derived from career allow rate.

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