US 1235446

I'll run several targeted searches for the exact identifier before summarizing.

Sourcing note

The live searches did not return any authority-specific record for this number. A search for 1235446 combined with "Dastoli"/"trap door" returned zero hits, and the USPTO/CAFC-oriented query surfaced only unrelated modern matters (e.g., Fed. Cir. Nos. 2025‑1306/1307/1473, an appeal from IPRs on U.S. Pat. No. 10,894,503). I therefore relied on the authoritative full text supplied (https://patents.google.com/patent/[US1235446](/patent/US1235446)/en). Where the record is internally inconsistent, I flag it rather than correcting it.

US 1235446 — bibliographic summary

Uncertainties I will not paper over:

1. No abstract exists. This is a 1915‑filed/1917‑issued grant; the document has a specification and a single claim only. Any "abstract" for this patent would be a modern construction, not patent text. (Flagged as an uncertainty rather than fabricated.)
2. Internal number discrepancy. The OCR'd drawing-sheet headers read "1,285,446. Patented July 31, 1917," while the bibliographic metadata and page title give US1235446A. I am not auto-correcting either; the authoritative identifier I was given is 1235446.
3. Associated application identifiers. The record lists priority to/from "US1388215A" (also titled "Trap-door"), while the specification states Serial No. 13,882, filed 1915‑03‑12. These do not map cleanly onto one another; treat the family linkage as uncertain.
4. Classification mismatch. E05F5/12 ("preventing the closing of a wing before another wing has been closed") does not describe this disclosure; it appears to be a modern reclassification artifact.
5. No litigation found. Nothing ties this patent to any CAFC 2026 docket — unsurprising given expiration in 1934. My searches found no such docket; absence of a hit is not proof of non‑existence, but I have no basis to assert any proceeding.

Plain-language overview of the claims

The patent contains exactly one claim, which is independent (a single‑claim, combination‑type claim in the style of the era). There are no dependent claims.

Claim 1 — combination of five cooperating elements:

1. Frame. A rectangular metal frame of side and end beams, each beam being an L/angle section: an inner vertical flange plus a horizontal flange projecting outwardly from the upper edge of the vertical flange.
2. Bearings in the frame. The end vertical flanges carry horizontally aligned bearing openings located near the junction of the side and end flanges.
3. Pintle rods. Continuous horizontal pintle rods whose ends sit in those alined openings.
4. Bracket supports. Rigid bent supporting brackets running from the pintle rods out to the outside of the frame; one part is rigidly fixed to the side vertical flanges and to the underside of the side horizontal flanges, and the bracket's inner end has an eye that receives and supports the pintle rod.
5. Door sections and straps (the functional core). Two door sections meet at the center of the opening; their rear edges project beyond the plane of the pintle rods and lie close against the inner vertical side flanges when closed. Metal straps are fastened at both ends to the lower face of each door section and embrace the pintle rods between their ends. The pintle rods sit adjacent the inner vertical flanges so that (a) the doors can swing on them, and (b) when the doors are open, their rear edges are supported between the pintle rods and the vertical flanges.

Practical reading: the claimed point of novelty is the way the hinge is anchored — an off‑set bracket bolted to the outside/lower faces of angle‑iron framing that carries the pintle in an eye, plus wrap‑around straps on the door underside, so that when the doors are lifted open their back edges tuck behind the pintle rods and rest against the frame webs rather than cantilevering into the opening. The specification states this gives a firm hinge support, an essentially unobstructed opening, and resistance to "rough handling."

Unclaimed subject matter disclosed but not claimed (worth noting for completeness, since it is not part of the claim): the spring‑loaded latch with beveled bolt head 21 entering frame opening 22, shoulder 23, spring 24, slot‑and‑stud guide 25/26, handle arm 28, and retaining pin/nail 29 in perforation 30; and the overlapping contiguous door edges 16/17.

Legal significance: with expiration on 1934‑07‑31, this disclosure is public domain and cited only as prior art / background (as in the three "cited by" documents listed above).

I'll search for litigation involving US patent 1235446.

Initial searches returned no relevant hits. Let me search patent litigation databases specifically.

Let me run a few more targeted checks on litigation-specific databases.

Litigation Search: U.S. Patent No. 1,235,446

Result: No litigation found. I located no district court, ITC, PTAB, or CAFC proceeding involving U.S. Patent 1,235,446.

Per your instruction not to auto-correct or substitute similar numbers, I searched the literal identifier 1235446 / 1,235,446 and discarded results that matched other identifiers (e.g., the 1235446 hits returned were a Mississippi LLC business ID and a Florida FEI number; a CN 1235446 A Chinese publication appeared in an EPO family listing for EP 0940944; and various unrelated dockets and PTAB proceedings matched only on generic terms).

Patent identification (as listed on the source page)

Specific case data requested

For each of the requested fields — plaintiff(s), defendant(s), jurisdiction, case number, filing date, and outcome/status — there is nothing to report. No case could be identified, so no fields can be populated.

Searches performed

• General web search on the patent number plus "litigation" / "infringement lawsuit" / "case docket."
• Searches aimed at the Unified Patents litigation/PTAB case lists (portal.unifiedpatents.com), Docket Alarm PTAB and district court records, CourtListener/RECAP, and PACER-oriented result sets.
• Inventor-name search (Dastoli) combined with the patent subject matter.

None returned a case citing or asserting this patent.

Important caveats (please read before relying on this)

1. Why the absence is expected. This is a 1915-filed, 1917-granted patent that expired in 1934. The litigation databases you named are largely oriented to the post-2011 AIA era (Unified Patents' portal is predominantly IPR/PGR and modern district court cases). Any enforcement suits from roughly 1917–1934 would generally not appear in these systems, and PACER's district court coverage is not complete for that era.
2. A negative result here is not proof that no action ever existed. Historical infringement suits from the 1910s–1930s are documented, when at all, in period sources such as the Federal Reporter, the U.S. Patent Quarterly, and the Official Gazette — not in modern docket databases. Confirming a true negative would require a Westlaw/Lexis KeyCite and CourtLink litigation-history search on the patent, plus a search of historical Federal Reporter volumes.
3. Source discrepancy, reported literally. The Google Patents page for US 1,235,446A simultaneously lists the application as "US1388215" and lists US1388215 as a separate "Trap-door" priority application with the same 1915-03-12 filing date. The patent's own specification recites "Serial No. 13,882." I am not resolving or correcting this inconsistency; I am flagging it as it appears.
4. No assignee to trace. The patent is listed with an individual inventor/assignee, so there is no corporate entity whose litigation docket could be cross-checked for enforcement history.

Bottom line

Based on the sources available to me, no litigation is known involving U.S. Patent 1,235,446. If you need a definitive negative for litigation-history purposes (e.g., for an IDS or a reexamination-style litigation search report), I recommend a paid Westlaw KeyCite/CourtLink and Lexis search plus a historical Federal Reporter check, since the free portals you listed do not reach the 1917–1934 window in which this patent could have been enforced.

I'll verify the structured data against public sources before concluding.

Proceedings overview

Total AIA trial proceedings on file: 0. The USPTO Open Data Portal structured block reports no AIA trial proceedings for US 1235446, and web searches of PTAB dockets, PTAB E2E/PTACTS, and CourtListener surfaced no IPR, PGR, or CBM naming this patent — no active proceedings, none with claims invalidated, none with claims sustained, none settled, and no institution denials. The defensive posture is dictated not by any PTAB outcome but by the patent's own status: US 1235446 issued 1917-07-31 on an application filed 1915-03-12, and the structured record shows "Expired - Lifetime" with an anticipated expiration of 1934-07-31. There is no live patent to assert, so there is no PTAB history to litigate over — and, as a matter of law, no AIA trial could have existed against it.

Proceedings detail

No proceeding entries follow, because there are none to report. Two points explain why this is a structural certainty rather than a gap in the data:

1. The AIA trial regime postdates this patent by roughly a century. Inter partes review, post-grant review, and covered business method review were created by the Leahy–Smith America Invents Act (2011) and became available in 2012. As the PTAB's own public materials explain, IPR, PGR, and CBM are the Board's AIA trial types, supplementing its older ex parte appeal, interference, and reexamination dockets (see USPTO PTAB overview, https://prod-web-alb-tg.uspto.gov/sites/default/files/documents/20210824-PTAB-Stadium_Tour_presentation__short_version_edited-IQ_808095-Updated_for_Aug_2021-IQ_819421-Final.pdf). US 1235446 expired in 1934 — 78 years before the first IPR was ever filed.
2. Even setting timing aside, PGR and CBM are categorically unavailable. PGR reaches only patents with an effective filing date on or after 2013-03-16; this patent's filing date is 1915-03-12. CBM requires a covered business method patent, i.e., one claiming a method or apparatus for a financial product or service — this patent claims a metal trap-door hinge and latch, which is not remotely a "covered business method."

I did not find any older Board proceeding (interference, reexamination, or ex parte appeal) touching this patent either, and I want to be explicit about the limits of that statement: pre-AIA interference and reexamination records from the 1910s–1930s are not comprehensively digitized in searchable form, so I cannot rule out a paper-era proceeding that never made it into a modern database. What I can say with high confidence is that no AIA trial proceeding has ever been instituted or even petitioned against US 1235446.

On the identifiers in the record (flagged, not corrected)

The Google Patents family record at https://patents.google.com/patent/US1235446/en contains an internally inconsistent pairing worth noting before anyone builds a docket off it: the "Application number" table lists US1388215 as the priority/family application for US 1235446, while US 1,388,215 is itself a separate granted patent ("Trap-door," filed 1915-03-12). Prior-art keywords for the family are "door, trap, pintle, flanges, vertical," and the family ID is 3303269. I am reporting these exactly as the source states them and not auto-correcting them, per the operating rules — but a defendant's counsel should not cite "US1388215" as this patent's application number without independently confirming it, since the serial number in the specification text reads "Serial No. 13,882."

Not PTAB activity (avoid a false hit)

The "Cited By" list in the structured data — US2725003 (Lyons, sheet metal closures for hatchways, 1955-11-29), US3480316 (Westover, safety door fastener, 1969-11-25), and US4452476 (Stole, security device, 1984-06-05) — are later patents that cite US 1235446 as prior art. They are not PTAB proceedings, not petitions, and not party to any challenge. Likewise, the "Similar Documents" list (e.g., US2791348 canopy lid hinge, US1573231 hinge) is a machine-similarity artifact with no adversarial significance.

Strategic summary

Claim status: an academic question. US 1235446 contains exactly one claim — a single combination claim (the specification refers to "the claim hereto appended," singular), covering the combination of a rectangular L-beam frame, horizontally alined bearing openings in the end vertical flanges, continuous horizontal pintle rods in those openings, rigid bent supporting brackets secured to the side vertical flange and the underside of the side horizontal flange with an eye receiving the pintle rod, door sections meeting at the opening's center with rear edges projecting beyond the plane of the pintle rods, and metal straps secured to the door undersides embracing the pintle rods. Because no IPR was ever filed, that claim was never canceled, never narrowed, and never sustained by the Board — it is untested at the PTAB, not "hardened." It is nonetheless expired: the structured record shows the patent reaching anticipated expiration in 1934-07-31. Cancellation by the Board is functionally irrelevant when the statutory term has already run and the patent is unenforceable for the sole independent reason that its term ended 92 years ago.

Estoppel landscape: empty, and it doesn't matter. Because no petitioner ever filed an IPR or PGR against this patent, no § 315(e)(2) estoppel attaches to anyone. There is no petitioner, no privity chain, and therefore no bar on any prior-art ground — but there is also no reason to invoke one. Practically, § 315(e)(1) estoppel (Board proceedings) and § 315(e)(2) estoppel (district court / ITC) only constrain a party that petitioned; a defendant who never filed is free to raise all invalidity grounds, including § 112 and § 101 defenses that are unavailable in an IPR under § 311(b) (which limits IPR to § 102 and § 103 grounds on patents and printed publications, as the PTAB overview confirms). The far cleaner defense is temporal: the patent expired in 1934 and cannot be infringed today.

Pattern signals: none. No repeat petitioner, because there is no petitioner. No patent-owner appeal practice at the Federal Circuit, because there is no Board decision to appeal. No defensive aggregator — nothing in the record (family ID 3303269; assignee listed as "Individual" / original assignee "Individual"; inventor Thomas Dastoli of Utica, Oneida County, New York) indicates any Unified Patents, RPX, or other aggregator involvement. The "Individual" assignee entries are the ordinary consequence of a 1915-era individual inventor grant, not a sign of a non-practicing-entity campaign.

Recommended next steps

If you have received a demand letter citing US 1235446, treat demand-letter provenance as the real issue, not validity. There is no PTAB proceeding to link you to, and there never could be one for this expiration year. The response is not an IPR petition; it is a records check and a cease-and-desist letter telling the sender that:

1. The patent expired. Per the structured record at https://patents.google.com/patent/US1235446/en, the anticipated expiration is 1934-07-31 and the legal status is "Expired - Lifetime." A patent whose term ended in 1934 cannot support an infringement claim in 2026. There is no "FWD to link to" and no disposition to quote — because no FWD exists.
2. Threats premised on this patent are baseless on their face, and if the sender is asserting infringement of an expired patent to extract a license payment, that is a fact pattern worth documenting for fee-shifting under 35 U.S.C. § 285 and, depending on the conduct, state unfair-competition exposure. Note that § 285 fee-shifting tied to litigation positions is generally for litigation misconduct; conduct in pre-suit demand letters is better addressed through state law.
3. Confirm you have the right patent number. Demand-letter campaigns occasionally paste a number that does not match the asserted technology. This patent's subject matter is a metal trap door with an L-beam frame, pintle-rod hinges, and a spring latch — an industrial hardware patent, not software. If the letter describes anything else, the number is being used loosely and the demand should be challenged on identification grounds as well.

If you are a defendant elsewhere and were hoping to use this patent's PTAB history as precedent (e.g., to argue the Board has previously construed a "pintle rod" or "L-beam frame" limitation): there is no such precedent. You cannot cite an FWD or an institution decision for US 1235446, because none was ever issued. Any claim-construction citation on these terms must come from other patents or from district court decisions.

Bottom line for a defendant: the absence of PTAB activity here is not the usual "nobody has bothered to challenge it yet" signal. The ordinary inference — that a well-asserted, live patent eventually attracts IPRs — does not apply, because this patent could not be challenged in an AIA trial during any period in which it was enforceable, and it has been expired since 1934. Do not spend IPR budget on US 1235446. Spend five minutes verifying the patent number on the demand letter and send a documented expiry rebuttal.

I'll start by verifying the patent's identity and checking for any recorded assignment activity.

No results. Let me check the USPTO assignment databases and Google Patents legal events directly.

Inventors

Notes on unusual patterns: none detectable. The declarations are witnessed by two individuals — Rocco M. La Bella and Billy Sinisgalli — who appear to be local witnesses of signing rather than attorneys of record (no firm, no address, no registration number is given for them in the printed patent). There is no sign of a corporate inventor group, no co-inventor set, and therefore no "inventor-drain" pattern to test. The usual tell for a pre-fire-sale portfolio — all inventors leaving an assigned company within 12 months — is inapplicable because there was never a company assignee to leave.

Original assignee

None — the patent issued to Thomas Dastoli as an individual. Both the "Original Assignee" and "Current Assignee" fields on the Google Patents record read "Individual," and the record carries the boilerplate disclaimer that these listings may be inaccurate.

• The patent is a paper/mechanical patent for a hinged, angle-iron-framed trap door for a trap-door opening — a small hardware article, not a platform technology.
• Primary line of business of the assignee: N/A (natural person). No product-shipping entity is identified in the patent, and no corporate successor appears anywhere in the record.
• Current status: expired. Filed 1915-03-12 (Serial No. 13,882), granted 1917-07-31, and anticipated expiration 1934-07-31 — i.e. the 17-year term then in force. Google Patents lists legal status as "Expired – Lifetime." The claimed subject matter has been in the public domain for roughly 92 years.

One literal-reading caution: the Google Patents "Family" tables render the priority filing as "US1388215A." This should not be read as a separate related patent. US 1,235,446's own specification states "Serial No. 13,882," and the only family entry is the filing itself — the "US1388215A" label is a Google Patents artifact for that single application. There is one application, one publication, and no continuation/division/reissue in the record.

Assignment timeline

The USPTO Assignment Center has no records for this patent, and no assignment appears anywhere in the disclosed record. Stating this plainly, as instructed:

• The Google Patents legal-events block for US 1,235,446 contains only four lifecycle entries and zero assignment events: (1) application filed by "Individual," (2) priority to US1388215 / application filed by Individual, (3) application granted 1917-07-31, (4) anticipated expiration 1934-07-31. No reel/frame, no conveyance type, no assignor/assignee, and no correspondent of record is exposed.
• The "Priority Applications," "Applications Claiming Priority," and "Family Applications" tables each list only the original application. A transfer to a third party would normally leave at least a name change in the "Current Assignee" field; that field still reads "Individual."
• Coverage caveat on the primary source: the USPTO Assignment Center database of record is oriented toward electronically recorded assignments, effectively the 1980-present era. A grant that expired in 1934 would not appear there even if a paper assignment had once been recorded at the old Patent Office — those pre-1980 paper records are largely outside the searchable online index. So the finding is: no assignment is recorded in the accessible sources, and there is no modern chain at all.
• I was unable to retrieve a live Reel/Frame, correspondent name, or recorded date because no such record exists to retrieve; searches of the Assignment Center, Google Patents legal events, and general web sources returned nothing for this number beyond the patent document itself.

Because there are no recorded assignments, I am stopping here, per the instruction not to continue past this section. I did not fabricate a Reel/Frame, a correspondent, or an LLC chain. The only additional factual items, offered as closure rather than as an assignment analysis:

Timeline diagram (patent life — not an ownership chain):

timeline
    title Timeline of US 1235446
    1915 : Filed by Thomas Dastoli
         : Filed at Utica New York
    1917 : Patent granted
    1934 : Expired by term
         : Public domain since

Verdict: Insufficient data.

Reasoning: the record contains no post-issuance assignment of any kind — no reel/frame, no transfer to any LLC, no correspondent — so the NPE framework (shell-entity transfer, cascading transfers, pre-litigation transfer, privateering, defensive aggregation) has nothing to attach to. The five other requested signal categories also fail on the evidence: no asserter name appears, no litigation is associated with the number, and the patent expired 1934-07-31 and has been unenforceable for over nine decades, which makes modern NPE assertion categorically impossible. Applying Delaware/Texas LLC or RPX/Unified Patents analysis to a 1917 trap-door patent would be an anachronistic fabrication, so I decline to assert one.

Verify at the USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (patent number search), with the same underlying records at https://assignment.uspto.gov/patent/index.html — search "1235446," which returns only the original grant and no assignment entries.

I'll run targeted searches on the literal number before analyzing.

Let me run a few more targeted checks before drawing conclusions.

Prior-Art Analysis for U.S. Patent 1235446 ("Trap-door")

1. USPTO / database search on the literal number

I searched the literal strings 1235446, US1235446, and US1235446A (with and without "trap door"/"Dastoli"). Results:

• No USPTO full-text record was retrievable through live web search for a trap-door patent numbered 1235446. My prior searches (documented in the previously generated sections) returned only unrelated matches on the same digit string — a Mississippi LLC registration, a Florida FEI number, the chemical CAS 1285446-04-9, and the Chinese publication CN 1235446 A (an unrelated elliptic-curve-cryptography document in the EP 0940944 family). Per the no-auto-correction rule I do not substitute any of those for this patent.
• The only live web hit that actually identifies US1235446A is a forward-citation entry in Google Patents for US2725003A, reading: "US1235446A (en) — 1915-03-12 — 1917-07-31 — Thomas Dastoli — Trap-door." (https://patents.google.com/patent/US2725003A/en)
• Accordingly, I rely on the authoritative full text supplied (https://patents.google.com/patent/[US1235446](/patent/US1235446)/en).

2. The critical finding: this patent cites no prior-art references

Before listing references, the decisive point must be stated plainly:

U.S. Patent 1235446, as published, contains no "References Cited" / "Citations" list. The fetched record moves directly from the classification data to the specification ("Definitions"/description), then to Cited By and Similar Documents. There is no examiner-applied or applicant-supplied backward-citation set.

This is consistent with its era. The application was filed 1915-03-12 and granted 1917-07-31 — decades before the modern "References Cited" front-page convention and before the 1952 Act. The specification discusses no prior patents or publications; it recites only the object of the invention and the description of parts. So, strictly construed, the patent citations "for 1235446" consist only of later documents that cite it, not documents it cites. I flag this rather than manufacture a citation list that the record does not contain.

3. Documents that cite US1235446 (forward citations — not § 102 prior art)

The record's only citation block is "Cited By (3)." All three postdate 1235446 and therefore cannot anticipate or render obvious it under 35 U.S.C. § 102 (or under any pre-1952 equivalent, since a later document is definitionally not "prior"):

Anticipation analysis for F1–F3: none. An anticipating reference must predate the invention/publication and disclose every element of the sole claim (see § 5). Each of F1–F3 is dated 33–67 years after the 1917 grant, so none is available as prior art against US1235446. They are relevant only as evidence that later workers in the hatchway/closure field looked back to this disclosure.

4. Related/family document

• US 1388215 A, "Trap-door," priority/filing date 1915-03-12, publication date as listed alongside 1235446 in the header pairing. Same title, same filing date, same era. The page simultaneously treats US1388215 as the priority application for US1235446 and as a standalone "Trap-door" document, while the specification itself recites "Serial No. 13,882."

Prior-art effect: none. A same-filing-date, same-title document associated with the same application/serial cannot be § 102 prior art to the very patent claiming priority to it (same date, same subject matter). Flagged discrepancy (not resolved): the numbers US1388215 / "Serial No. 13,882" / US1235446 do not map cleanly onto one another, and the OCR'd drawing-sheet headers read "1,285,446." Per the no-auto-correction rule, I report these literally and treat 1235446 as the governing identifier.

5. Candidate prior art from the "Similar Documents" list (unverified — not citations of record)

The record's "Similar Documents" are an algorithmic similarity list, not examiner citations. Those published before the 1915-03-12 filing date are the only ones that could even theoretically serve as § 102 prior art. For completeness (with the caveat that I could not review their full texts, so I make no positive anticipation finding):

(Documents dated 1915-06-29 or later — e.g., US1144564, US1307996, US1334442, US1528752, US1573231, US1872590, US2791348 — postdate the filing date and are excluded on their face; their application dates would need checking, but the listed publication dates bar them.)

Which claim(s) any of these might anticipate: the patent has exactly one claim, so the only possible anticipation target is Claim 1. To anticipate Claim 1, a single reference would have to disclose all of the following, in combination:

1. a rectangular metal frame of side and end beams, each with an inner vertical flange and a horizontal flange projecting outwardly from the upper edge of that vertical flange;
2. horizontally alined bearing openings in the end vertical flanges, near the side/end flange junction;
3. continuous horizontal pintle rods with their ends mounted in those alined openings;
4. rigid bent supporting brackets extending from the pintle rods to the outside of the frame, rigidly secured to the side vertical flanges and to the underside of the side horizontal flanges, with an eye at the inner end receiving/supporting the pintle rod;
5. two door sections meeting at the center of the opening, with rear edges projecting beyond the plane of the pintle rods and lying close against the inner vertical side flanges when closed; and
6. metal straps secured at both ends to the lower face of each door section and embracing the pintle rods between their ends, the pintle rods lying adjacent the inner vertical flanges so the doors swing and the rear edges are supported between the rods and the flanges when open.

On the titles/classifications alone, the gate/hinge/latch references above are in the same general mechanical field (swinging closures on pintle hinges), and one or more could conceivably disclose isolated elements — e.g., a pintle-and-eye hinge, or a frame flange. None, as far as I can verify, is directed to the specific angle-iron frame + off-set eyed bracket + wrap-around under-door strap combination that defines Claim 1. I therefore make no positive § 102 anticipation finding against Claim 1 on the present record.

6. Legal-standard caveat

Because the filing date is 1915-03-12, the governing novelty statute is the pre-1952 law (Rev. Stat. § 4886), not the modern § 102(a)/(b). The substantive test — a reference "patented or described in a printed publication" before the applicant's invention, with a two-year bar for public use/sale before filing — is what any historical prior-art challenge would have applied. Applying § 102(a)/(b) labels here is an analytical convenience, not the law in force.

7. Bottom line and recommended verification

1. US1235446A cites no prior-art references. The published patent and its Google Patents record contain no "References Cited"/"Citations" list. Any statement that it "cites" specific prior art would be fabricated; I will not make one.
2. The only citations of record attached to this number are forward citations — US2725003A, US3480316A, US4452476A — and none is § 102 prior art because all postdate the patent.
3. The "Similar Documents" list yields ~18 pre-1915 patents (listed in § 5) that are candidates only, unverified, and unsupported by any examiner citation; none can be confirmed to anticipate the single claim without full-text review.
4. To close this out definitively, a researcher should pull the examiner's file wrapper / original Patent Office record for the 1915 application (Serial No. 13,882) and run the pre-1915 references in § 5 through USPTO Patent Public Search and a full-text prior-art database — the free web record simply does not contain a citation set to analyze, which is a limitation of the record, not a negative finding that no art exists.

Note on identifiers: I have not corrected or substituted any number. The 1235446 / US1388215 / "Serial No. 13,882" / OCR "1,285,446" discrepancies already flagged in the earlier sections remain unresolved and are reported as they appear.

I'll pull the prior-art references listed on the page and verify what each one actually discloses before building the § 103 analysis.

Obviousness Analysis — US 1235446 ("Trap-door") under 35 U.S.C. § 103

Builds on the previously generated bibliographic, claim-overview, and litigation sections. Those sections are treated as authoritative here; I do not repeat them. One contradiction with my own earlier work is flagged in § 7 below.

1. Scope of the "Prior Art" section of this page — read this before the analysis

The Google Patents page (https://patents.google.com/patent/US1235446/en) organizes its art in three buckets, and only one of them can supply § 103 prior art:

Two further caveats:

• The page shows no examiner-cited art at all. The page legend reads "* Cited by examiner, † Cited by third party," but no asterisk or dagger is visible on the three Cited By rows in the fetched text. So I cannot tell from this record whether any of those three was examiner-cited, and in any event none is prior art. No anticipatory reference was cited against this patent on the face of the record I have.
• The Similar Documents list is a near-neighbor artifact, not a search report. Similarity ranking is not a relevance or patentability determination. I verified the actual disclosures of only a subset by live search; for the rest I have title and date only and will say so rather than assume content. See § 4.

Pre-filing (qualifying) references from the Similar Documents list, by date: US117691A (1871‑08‑01), US162011A (1875‑04‑13), US177102A (1876‑05‑09), US219024A (1879‑08‑26), US322239A (1885‑07‑14), US334797A (1886‑01‑26), US468769A (1892‑02‑09), US568688A (1896‑09‑29), US626753A (1899‑06‑13), US669208A (1901‑03‑05), US755551A (1904‑03‑22), US791223A (1905‑05‑30), US793485A (1905‑06‑27), US975361A (1910‑11‑08), US977457A (1910‑12‑06), US987469A (1911‑03‑21), US1114510A (1914‑10‑20), US1122849A (1914‑12‑29). Non-qualifying (post-filing): US1144564A (1915‑06‑29), US1307996A (1919), US1334442A (1920), US1528752A (1925), US1573231A (1926), US1872590A (1932), and the three Cited By documents.

2. Governing legal standard

Because the application was filed 1915‑03‑12, pre‑AIA § 103 applies as a matter of statutory vintage. Any modern validity analysis nevertheless proceeds under Graham v. John Deere Co., 383 U.S. 1 (1966) (scope/content of art; differences; PHOSITA level; secondary considerations) and KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (expansive, flexible motivation; "obvious to try"; predictable results). The historical "flash of genius" gloss of Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84 (1941) has been superseded and should not be applied.

PHOSITA definition I apply: a mechanic or millwright of ordinary skill in the 1910–1915 metal-door and gate-hardware art, familiar with angle-iron framing, strap/eye hinges, and spring-bolt latches — no more.

Analogy: all of the qualifying references except the "Truck" and "Portable booth" entries are drawn from the same field of endeavor (swinging closures and their hinges/latches) or are reasonably pertinent to the problem Dastoli faced (anchoring a hinge to a metal frame without intruding into the opening). They are therefore analogous art under In re Bigio / In re Clay.

Anticipation posture: Claim 1 is a single independent combination claim. No single reference in the list discloses angle-iron frame + alined end-flange bearing openings + continuous pintle rods + frame-mounted bent eyes + door-mounted wrap-around straps. § 102 anticipation is not sustainable on this record; the case is a § 103 case.

3. Claim 1 decomposed into limitations

Limitations D and F together create a dual-bearing hinge (eye fixed to the frame and strap fixed to the door, both on the same pintle). Limitation F's last clause (open-position back-edge support) is the functional crux.

4. Reference disclosures (verified vs. title-only)

Verified by live search:

• US791223A — N. & G. Soesbe, "Gate," filed 1905‑01‑21, granted 1905‑05‑30 (https://patents.google.com/patent/US791223A/en). Discloses a pintle-rod 5 clamped to a post; upper and lower hinge members each "constructed of a single piece of metal, such as strap-iron, the material being centrally bent to form an eye 11 to receive the pintle," with sides riveted together ahead of the pintle, angularly bent U-shaped side bends 13 to seat the inner end bar, terminal parallel portions embracing the adjacent rail and bolted, and inwardly extending flanges 17/18 arranged on the upper/lower face of a gate rail. This is the single most on-point structural reference: bent strap-metal + eye + riveted faces + flanges engaging rail faces.
  Caution flag: the PDF's OCR header on the same document reads both "No. 791,223" and "No. 791,228," with the same application (Serial No. 242,124, filed Jan. 21, 1905) — an internal OCR inconsistency. I cite it literally as the page lists it (US791223A) and am not auto-correcting either number.
• US117691A — Nathaniel Sehner, "Improvement in Spring-Hinges," 1871‑08‑01 (https://patents.google.com/patent/US117691A/en). Discloses a plate A with arm A1 and pintle A2 "formed at the outer enlarged end" of the arm — i.e., a frame/post-mounted plate offsetting the pintle, with flanges (a, a′) along a recess — and a cooperating part B screwed to the shutter with a socket riding the pintle. Directly relevant to limitations C/D (offset frame-mounted pintle carrier) and F (socket embracing pintle).
• US793023A — H. A. Paquette, "Hinge," 1905‑06‑20 (https://patentimages.storage.googleapis.com/4e/06/ed/09a6e32c915dcf/[US793023](/patent/US793023).pdf). Discloses a pintle integral with the butt of one hinge section and a "knuckle or walls 8 … cylindrical bore … corresponding in diameter to the pintle, over which it is adapted to slide," plus a slotted sleeve 10 slipped over the pintle. Relevant to a door-mounted sleeve/strap embracing the pintle (limitation F).
• US1114510A — Emanuel H. Owens, "Mine-car-door fastener," filed 1914‑08‑18, granted 1914‑10‑20 (https://patents.google.com/patent/[US1114510](/patent/US1114510)#1). Discloses a heavy metal end door/gate 7 swinging on a hinge 8, with bearing straps 10 on the car sills, a crank rod 11 with angular ends and rings 13, upright pins 14 with eyes 15/16, and gravitating catch-weights 18 on pendants 17. Relevant as industrial-metal-closure context and positive-locking art — but note its hinge is at the upper edge and its locking is crank/gravity, not spring-bolt.
• US975361A — Johnson, "Latch," 1910‑11‑08 (confirmed only indirectly, via a citation table in US7726706 listing "975,361 A * 11/1910 Johnson" in a latch-mechanism context). Relevant to the unclaimed spring-bolt latch.

Title/date only (content NOT verified — I make no disclosure assertions for these): US162011A (fasteners for doors and shutters), US177102A (door/window fasteners), US219024A, US334797A, US468769A, US793485A (farm/fence/swinging gates), US568688A, US322239A, US626753A (portable booth), US669208A (tilting gate), US755551A (folding door), US977457A (end-gate), US987469A (gate-fastener), US1122849A (truck). The gate-family entries are topically plausible analogous art for limitations A–C (hinged closures in frames); the "Truck" and "Portable booth" entries are the weakest on analogy.

5. Proposed § 103 combinations

Combination 1 (primary): US791223A in view of US117691A and/or US793023A, applied to an angle-iron trap-door frame

• US791223A supplies limitations D (a rigid bent metal member with a formed eye receiving a pintle, flanked by angular bends and rail-embracing faces, secured by rivets/bolts through face-engaging flanges) and much of F (a metal strap-like member embracing a rail/pintle region and fastened at its ends).
• US117691A and US793023A supply the complementary half of the dual bearing: a pintle carrier offset from its mounting plate (Sehner's arm A1/A2) and a door-side sleeve/knuckle that slides over and embraces the pintle (Paquette).
• Angle-iron (L-beam) framing with an inner vertical web and an outer horizontal flange at the top edge — limitation A — is elementary structural-steel construction practice of the period; the page's own keyword set (flanges, vertical) and the specification's statement that the L-beam frame "can be quickly and snugly placed in the aperture … without the aid of exterior attachments" frame it as conventional shop practice, not as the asserted novelty.
• Motivation: Dastoli's stated problem — "affording a firm support at the hinges so that the metal trap doors will stand a relatively large amount of use and abuse" — is precisely the problem Soesbe addressed for a heavy swinging gate ("a simple, inexpensive, and efficient one of great strength and durability," hinge "capable of reinforcing and securely bracing the same"). Both are heavy swinging closures hinged on a strap-and-pintle axis. A PHOSITA seeking to hang a metal door in an angle-iron frame, where a mortised butt hinge has nowhere to seat, would predictably look to the strap-hinge/gate-hinge art and bend a strap-metal bracket to lie against the two faces of the angle iron, carrying the pintle in a formed eye. KSR: predictable result, known technique, same field.
• No change in principle of operation: the Soesbe bracket performs the same eye-on-pintle function when riveted to an L-beam rather than bolted to a wooden rail. In re Ratti / MPEP 2143.3 does not bar the combination.

Combination 2: US1114510A (Owens) in view of US791223A and US975361A

• Owens supplies the all-metal door/gate-in-a-metal-body, hinge-mounted, positive-lock, high-abuse industrial closure context, plus bearings/seats (10) and aligning eye/pin couplings (15/16) that a PHOSITA would recognize as a bearing-and-pintle arrangement.
• US791223A + US975361A supply the strap-eye hinge and the spring-bolt latch, respectively.
• Motivation: same field (mine-car/hatch-type heavy metal closures), same problem (keeping a heavy metal leaf securely hinged and locked under abuse). A PHOSITA optimizing Owens' swinging end gate for a floor opening would adopt the more robust strap-and-pintle hinge of Soesbe and the spring latch of Johnson.
• Weakness: this combination proves the environment and the latch well, but it contributes little to limitations A, D (underside-of-horizontal-flange fastening), or the open-position back-edge support of F.

Combination 3 (latch-only, for completeness): US975361A / US987469A / US177102A / US162011A / US1114510A

These can render the spring-bolt latch (beveled head, shoulder, spring, slot-and-stud guide, handle, retaining pin) obvious — but that subject matter is unclaimed (see the earlier claim-overview section). It cannot support a § 103 rejection of claim 1, which does not recite the latch.

6. Where a § 103 case on this record is weak — the limitations that resist

A rigorous rejection must account for every element. On the art actually listed on this page, these are the pressure points:

1. Limitation A's specific orientation — horizontal flange projecting outwardly from the upper edge of the inner vertical flange. No listed reference is shown to disclose that frame profile. It must be carried as conventional angle-iron framing, and the record contains no structural-steel reference to do so. This is the kind of gap that a "conventional practice" assertion can fill, but it is an assertion, not evidence.
2. Limitation D's fastener locations — the bracket secured to the exterior face of the side vertical flange and the underside of the side horizontal flange, with the eye spaced from the adjacent vertical flange. Soesbe's flanges 17/18 sit on rail faces, not on the two orthogonal faces of an L-beam, and Soesbe's pintle is fixed to the post while the eye is on the gate — the inverse of Dastoli's frame-side eye. Carrying this across requires the reference to be modified rather than merely combined.
3. Limitation F's open-position clause — "the rear edges of the door sections between the pintle rods and said vertical flanges when the door sections are in open position." No listed reference is shown to teach any open-position back-edge support, let alone the claimed geometry (rear edges projecting beyond the pintle plane and being wedged between pintle and frame web). This is the asserted point of novelty and the hardest limitation to meet. It is a positional/functional limitation that the combination must be shown to inherently produce or that the art must teach; a bare "obvious to try" argument is unlikely to suffice for this element alone.
4. Bodily-incorporation tension. Because D and F both mount on the same pintle, grafting Soesbe's gate-side eye onto a frame-side bracket risks double-eyeing the pintle; the combination must be re-designed (frame-side eye + door-side strap), which is a stronger change than a mere substitution and invites a "change in principle of operation" argument (In re Ratti).
5. Non-analogous outliers. US1122849A ("Truck") and US626753A ("Portable booth") are weak on analogy and should not be relied on for hinge structure.
6. A negative is not a finding. The four large pre-1915 US patents I could not verify (US162011, US177102, US219024, US322239, US334797, US468769, US568688, US669208, US755551, US793485, US977457, US987469) may well be the strongest art here or may be irrelevant; I decline to characterize them from their titles.

7. Secondary considerations (Graham factor 4) and a contradiction to flag

• Record is silent on commercial success, long-felt need, failure of others, copying, and licensing. The patent shows an individual assignee and, per the litigation section, no enforcement history — so there is no nexus evidence and no presumption of validity already litigated.
• The three Cited By documents (1955/1969/1984) show continued work in hatchway sheet-metal closures, safety door fasteners, and security devices. They are not secondary-consideration evidence (no nexus, and they post-date expiration by decades).
• Contradiction flagged (per the instruction to flag rather than silently reconcile): my earlier bibliographic section described the page as listing a "Cited By (3)" set and noted the OCR drawing-header discrepancy ("1,285,446" vs. "1,235,446"). Consistent with that, the live search above returned a document whose OCR shows both "No. 791,223" and "No. 791,228" with the same Serial No. 242,124. I am reporting both readings and correcting neither, per the strict rule. If either number is being relied on as a formal citation, verify against the printed patent copy.

8. Bottom line

• Anticipation (§ 102): Not sustainable on the art listed on this page. No single reference discloses the full combination of claim 1.
• Obviousness (§ 103): A colorable but incomplete case can be made on the page's own list, principally US791223A (Soesbe, 1905) as primary, in view of US117691A (Sehner, 1871) and/or US793023A (Paquette, 1905), with US1114510A (Owens, 1914) and US975361A (Johnson, 1910) supplying the heavy-metal-closure and latch context, and L-beam frame construction taken as conventional practice. Motivation is strong on the shared problem (robust hinging of a heavy swinging metal leaf where a butt hinge cannot seat) and the shared field (gate/door hinges), and no reference's principle of operation is destroyed by the combination.
• The rejection would likely fail on limitations D and F — specifically the underside-of-horizontal-flange fastening, the frame-side eye spaced from the vertical flange, and above all the open-position support of the door's rear edges between the pintle rods and the inner vertical flanges, for which the listed art shows no teaching. Those elements, not the hinge generally, are what a challenger would have to find new art for.
• Practical note: the patent expired 1934‑07‑31 (anticipated). This analysis is therefore academic unless invoked in a validity/background context; there is no identified litigation or PTAB proceeding in which it would matter (see the litigation section, which I incorporate rather than repeat).

Confidence: High on the reference dates and on the Soesbe/Sehner/Paquette/Owens disclosures (directly verified). Low on any inference about the unverified title-only references and on the classification/identifier oddities, which I have flagged rather than resolved.