Prosecution Insights
Last updated: April 19, 2026
Application No. 18/685,374

Proprotor Blade Retention System

Non-Final OA §102§112
Filed
Feb 21, 2024
Examiner
ZAMORA ALVAREZ, ERIC J
Art Unit
3745
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Archer Aviation, Inc.
OA Round
4 (Non-Final)
88%
Grant Probability
Favorable
4-5
OA Rounds
2y 5m
To Grant
99%
With Interview

Examiner Intelligence

Grants 88% — above average
88%
Career Allow Rate
458 granted / 519 resolved
+18.2% vs TC avg
Strong +22% interview lift
Without
With
+21.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 5m
Avg Prosecution
14 currently pending
Career history
533
Total Applications
across all art units

Statute-Specific Performance

§103
33.8%
-6.2% vs TC avg
§102
27.6%
-12.4% vs TC avg
§112
31.7%
-8.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 519 resolved cases

Office Action

§102 §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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 01/20/2026 has been entered. Applicant’s Submission of a Response Applicant’s submission of response was received on 01/20/2026. Presently claims 1-7, 9, and 12-15 are pending. Claims 8, 10, and 11 are canceled. Response to Arguments Applicant’s remarks and arguments with respect to the 35 U.S.C. 102 rejection for claim 1 have been fully considered and are persuasive. The prior art rejection for claim 1 has therein been withdrawn. However, the prior art rejections for claims 12, 14, and 15 are maintained (see claim rejections below). Claim Objections Claims 1, 9, and 14 are objected to because of the following informalities: Claim 1, line 3, change: “a first and a second proprotor blade pitch bearing…” Claim 1, line 5, change: “ Claim 1, line 15, change: “in a first and a second direction…” Claim 9, line 3, change: “pitch horn is [[either]] connected to, or is a part of,…” Claim 14: Limitations from the previously presented claim 14 (filed on 09/15/2025) in lines 2-3 appear to missing or are altered without being shown in the new claim set submitted on 01/20/2026. For example: “a proprotor” is missing in line 2 and “of the proprotor” is missing after “a proprotor blade root” in the newly amended claim 14. Claim 14, line 3, change: “a first and a second proprotor blade…” Claim 14, line 5, change: “and the second proprotor blade pitch bearing;” Appropriate correction is required. 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. Claims 5-7 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 pre-AIA the applicant regards as the invention. Claim 5 is indefinite because it is unclear whether the threaded split collar recited in line 2 of the retainer is the same split collar recited in line 10 of claim 1. Paragraph [0035] of the specification discloses and makes reference to split collar 107, which further comprises threads on the outside diameter. Further, throughout the specification, there is no other reference number distinguishing the split collar 107 from a different split collar. Therein, it is unclear how there can be two different split collars as recited in claim 5 (threaded split collar) and in claim 1 (split collar). Due to the ambiguity of the subject matter of claim 5 and the disclosure of the specification, it is unclear whether there are two different split collars or if the split collar referenced in each of the claims is the same. For these reasons, the metes and bounds of the claim cannot be determined, which renders the claim indefinite. Claim 6 is indefinite for the same reasons set forth in claim 5 above. It is unclear how there can be both a split collar and a threaded split collar. From the disclosure in [0035] of the specification, the split collar 107 comprises a threaded outer diameter, and therein it is unclear how there can be two distinguished collars as recited in the claim language. Claim 7 is further rejected for the same reasons set forth in claims 5 and 6. Dependent claims are also rejected due to their dependency of a rejected independent claim. Claim Rejections - 35 USC § 102 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. 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. Claims 12-13 and 15 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Cesare (U.S. 2,304,153). Regarding claim 12, Cesare discloses a proprotor system (Col. 1, lines 1-7) comprising: a proprotor blade (1) root (4); a blade pitch bearing (10, 11, as shown in Fig. 3); a split sleeve (5, Col. 2, lines 10-20) interposed between the proprotor blade root (4) and the blade pitch bearing (10,11 as shown in Fig. 3); wherein the split sleeve (5) is configured to transfer a force from the proprotor blade root (4) to a threaded split collar (a split collar 6, Col. 2, lines 10-20; split collar is configured to receive a force from the split sleeve since, as shown in Fig. 3, the split collar 5 is in contact and adjacent to sleeve 5, and therein the split sleeve 5 is configured to transfer a force from the split sleeve from the blade root 4; split collar 6 is threaded since a nut is on each side, as shown in Figs. 3 and 6-7, is used to fasten and secure the split collar 6 onto the blade as shown in Fig. 3). Further, the phrase “is configured to transfer a force from the proprotor blade root to a threaded split collar” merely represents an intended use or a manner in which a claimed apparatus is intended to be employed and does not differentiate the claimed apparatus from the prior art apparatus disclosed in Cesare. See MPEP 2114. MANNER OF OPERATING THE DEVICE DOES NOT DIFFERENTIATE APPARATUS CLAIM FROM THE PRIOR ART. Regarding claim 13, Cesare discloses wherein an outside diameter of the split collar (6) is larger than an inside diameter of the blade pitch bearing (as shown in Fig. 3, the outer diameter of the collar 6 is larger than an inside diameter of the bearing 10). Regarding claim 15, Cesare discloses an aircraft (aircraft, Col. 1, lines, 1-5) comprising: a proprotor (Col. 1, lines 1-7); a proprotor blade (1) root (4) of the proprotor; a split sleeve (5, Col. 2, lines 10-20) interposed between the proprotor blade root (4) and the blade pitch bearing (10,11 as shown in Fig. 3); wherein the split sleeve (5) is configured to transfer a force from the proprotor blade root (4) to a threaded split collar (a split collar 6, Col. 2, lines 10-20; split collar is configured to receive a force from the split sleeve since, as shown in Fig. 3, the split collar 5 is in contact and adjacent to sleeve 5, and therein the split sleeve 5 is configured to transfer a force from the split sleeve from the blade root 4; split collar 6 is threaded since a nut is on each side, as shown in Figs. 3 and 6-7, is used to fasten and secure the split collar 6 onto the blade as shown in Fig. 3). Further, the phrase “is configured to transfer a force from the proprotor blade root to a threaded split collar” merely represents an intended use or a manner in which a claimed apparatus is intended to be employed and does not differentiate the claimed apparatus from the prior art apparatus disclosed in Cesare. See MPEP 2114. MANNER OF OPERATING THE DEVICE DOES NOT DIFFERENTIATE APPARATUS CLAIM FROM THE PRIOR ART. Allowable Subject Matter Claims 1 and 14 are allowable over the prior art of record. Regarding claim 1, Cesare fails to disclose or suggest wherein the split-collar (6) is seated in the split collar groove on the split sleeve (5). Fig. 3 shows that the collar (6) is not seat in a groove on the split sleeve (5). Regarding claim 14, Cesare discloses an aircraft (aircraft, Col. 1, lines, 1-5) comprising: a proprotor (Col. 1, lines 1-7); a proprotor blade (1) root (4) of the proprotor; a first (10) and second (11) proprotor blade pitch bearing (as shown in Fig. 3); a bearing retention device (i.e., assembly comprising split collar 6, end cap fastener 13, and split sleeve 5 as shown in Fig. 3) configured to apply a preload force to the first proprotor blade pitch bearing (10) and the second proprotor blade pitch bearing (11, i.e., the preload force provided by the threaded end cap 13 into the housing maintains a compressive force (i.e., toward the right horizontal direction in Fig. 3) to maintain the bearings locked in position (i.e., bearing retention) and prevents the dislodging from the blade from the sleeve 5 due to centrifugal forces (i.e., which would direct the blades outward toward the left horizontal direction in Fig. 3), Col. 2, lines 21-32 and Col. 2, lines 13-20; the compressive force is caused by the abutment of the sleeve 5 which is tapered at location 7 against the shoulder 9 of the blade root, therein, in Fig. 3, the compressive force directions would be a first direction vertically down and a second direction vertically up caused by the abutment of the sleeve 5 against the root outer surfaces 4, Col. 2, lines 15-20); wherein the bearing retention device (i.e., assembly comprising split collar 6, end cap fastener 13, and split sleeve 5 as shown in Fig. 3) comprises: a split sleeve (5, Col. 2, lines 10-20) interposed between the proprotor blade root (4) and the first proprotor blade pitch bearing (10,11 as shown in Fig. 3). However, Cesare fails to disclose or suggest of a split-collar groove and the split-collar (6) seated in the split-collar groove; and a bearing preload nut engaged with the split-collar configured to apply preload to the first proprotor blade pitch bearing; wherein the preload force is configured to maintain the split sleeve in compression against the first proprotor blade pitch bearing and the second proprotor blade pitch bearing in a first and second direction; and wherein the first direction is opposite the second direction. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERIC J ZAMORA ALVAREZ whose telephone number is (571)272-7928. The examiner can normally be reached Monday-Friday 7:30 am- 5:00 pm EST alternating Fridays off. 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 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. /ERIC J ZAMORA ALVAREZ/Primary Examiner, Art Unit 3745 02/23/2026
Read full office action

Prosecution Timeline

Feb 21, 2024
Application Filed
Jan 23, 2025
Non-Final Rejection — §102, §112
May 27, 2025
Response Filed
Jun 11, 2025
Non-Final Rejection — §102, §112
Sep 10, 2025
Examiner Interview Summary
Sep 10, 2025
Applicant Interview (Telephonic)
Sep 15, 2025
Response Filed
Oct 14, 2025
Final Rejection — §102, §112
Jan 14, 2026
Examiner Interview Summary
Jan 14, 2026
Applicant Interview (Telephonic)
Jan 20, 2026
Request for Continued Examination
Feb 18, 2026
Response after Non-Final Action
Feb 23, 2026
Non-Final Rejection — §102, §112 (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

4-5
Expected OA Rounds
88%
Grant Probability
99%
With Interview (+21.9%)
2y 5m
Median Time to Grant
High
PTA Risk
Based on 519 resolved cases by this examiner. Grant probability derived from career allow rate.

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