US 221329

I'll run targeted searches for this exact number across patent and litigation sources, then summarize from the authoritative text I have.

US Patent 221,329 — Search & Analysis Report

Search scope executed: Google Patents/patentimages (authoritative full text + OCR of the original), USPTO-linked records within the Google Patents family/legal-status data, CourtListener/CAFC opinion feeds, and general web for litigation or appellate references to the string "221329."

Important identification caveat (applying the literal-ID rule): The string "221329" also appears in 2026 documents for entirely different identifiers — e.g. ANDA No. 221329 in Neurelis, Inc. v. Strides Pharma Global PTE Ltd., D. Del. 1:26-cv-00947, and AT 221329 T (an Austrian publication number in a WO search report). Those are not US Patent 221,329 and are excluded below. They are the only "221329" hits in 2026 dockets I found, and neither concerns this patent.

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Core bibliographic data

Abstract

This patent has no formal abstract (abstracts were not used in 1879). The statutory-equivalent statement of invention is:

"The invention consists in an animal-trap formed of a base-board rabbeted at the front and sides, and provided with side pieces, an inclined top having a hole for bait-rod, a bait-rod, and a spring connected with the bait-rod by a lever."

Stated object: "to furnish a strong, efficient, and durable trap for rats and other vermin."

Claims — plain language

The patent contains exactly one claim, which is the sole independent claim; there are no dependent claims. Verbatim:

"An animal-trap consisting of the base-board A, rabbeted at front and on the sides, the side pieces, B B, the inclined top C having hole a (a′), the bait-rod b (b′) c (c′), the levers d g (d′ g′), and the spring E, as shown and described."

Plain-language reading: The claim is a single omnibus "consisting of" claim to the whole assembled trap, defined by the cooperation of six named elements:

1. Base-board A — rabbeted along the front and both sides, leaving a raised central platform against which the sides mount; the front edge terminates in a sharp edge k that does the holding.
2. Two side pieces B B — nailed to the sides of the raised portion; they block the animal from reaching the bait laterally and, with brace D, leave light gaps so the bait is visible from the front.
3. Inclined top C — rests between the side pieces, rear end attached to the rear of the base-board, additionally supported by brace D; carries a bait hole a.
4. Bait-rod / staple b with bait-hook c — secured across the hole a, with the bait hook suspended from it.
5. Levers d and g — the spring hook/lever d swings on staple f in the front edge of the top; the smaller lever g is held by staple h. These form the trigger linkage; the specification states the extra small lever g makes the set "more unstable" (i.e., more sensitive/free-tripping) than direct connection of d to c, and alternatively the trap may be built without levers g and d and allow c to connect directly.
6. Coiled spring E — ends passed through the base and bent under it; its square loop runs along the sides and front of the base, driving the animal down onto sharp edge k.

Because the claim is in "consisting of" (closed) form and bottomed on "as shown and described," its scope is effectively limited to the illustrated combination — a characteristic 19th-century omnibus claim, not a modern element-by-element claim set. My plain-language breakdown above is my own construction; the claim language itself is the controlling text.

Documented citation history (for prior-art/comparison purposes)

• US 2005/0274057 A1 and US 7,543,407 B2 (Mcculloch, "Humane leg hold trap," 2004-06-09 priority) list US 221,329 as prior art — appearing in their U.S. patent-documents table as "221,329 A * 11/1879 Lewthwaite."
• Google Patents lists numerous "similar documents" (e.g., US 218,532; US 528,671; US 1,080,623), which are related art listings, not family members or legal relatives.

Litigation / CAFC 2026 status

• No CAFC 2026 docket and no district-court action involving US Patent 221,329 was found. Its 17-year term expired in 1896, so no live cause of action is plausible.
• No reissue, reexamination, or post-grant proceeding for this patent was found in the record.
• The only 2026 "221329" dockets located are the unrelated Strides ANDA No. 221329 matter (asserting entirely different patents, e.g. the '414, '664, '852, '061, '400 patents) — explicitly not this patent.
• The Conibear trap-validity appeal surfaced in my search concerns different patents and is not a citation to or proceeding on US 221,329.

Stated uncertainties

1. No assignee data exists for this patent — do not infer one.
2. Filing date conflict: June 12 vs. June 13, 1879, between the two authoritative renderings.
3. Inventor-name OCR variances ("Waiter"/"Walter"; "LEVVTHWAITE"/"LEWTHWAITE"; "WV.") are scan artifacts; the correct name appears to be George Walter Lewthwaite, but I present the variants literally.
4. Reference numerals differ between the Google Patents text (a, b, c, d, g, f, h, k) and the scanned original which primes them (a′, b′, c′, d′, g′, f′, h′, k′); both refer to the same elements.
5. The "Expired – Lifetime" legal status is Google's own disclaimer-backed assumption and carries no legal weight.

I'll search for litigation records involving US patent 221329.

Let me run additional targeted searches to be thorough.

Litigation Search Results: US Patent 221,329

Bottom line: I found no litigation — none in modern patent-litigation databases, and none in any other accessible source.

What I searched

Important false positive to flag (not litigation over this patent)

A search for "221329" surfaces Neurelis, Inc. v. Strides Pharma Global PTE Limited, D. Del. Case No. 1:26-cv-00947 (complaint filed 07/31/26) — but the "221329" there is FDA ANDA No. 221329, an abbreviated new drug application number, not U.S. Patent No. 221,329. The patents asserted in that case are the '664, '852, '061, '400, and '786 patents (Neurelis' diazepam nasal spray family). That case is not litigation involving US 221,329 and should not be reported as such.

I also saw unrelated "221" / "221,329"-adjacent hits (e.g., U.S. Patent 8,856,221 "the '221 patent" in IPR2015-01181; a '221 application in IPR2023-00070). None involve US 221,329.

Requested case table

Why this is the expected result (and the limits of the negative finding)

1. The patent has been expired since November 4, 1896. The Google Patents record for US221329A shows status "Expired – Lifetime" with an anticipated expiration date of 1896-11-04, derived from the 17-year term of the 1879 grant (patented Nov. 4, 1879; application filed June 12/13, 1879 — the two sources disagree on June 12 vs. June 13, and I'm not auto-correcting either). It has been unenforceable for roughly 130 years, so no infringement action could have been maintained in the modern era.
2. The patent is a one-claim, wooden rat trap. Claim 1 covers "[a]n animal-trap consisting of the base-board A, rabbeted at front and on the sides, the side pieces, B B, the inclined top C having hole a′, the bait-rod b′ c′, the levers d′ g′, and the spring E, as shown and described." It is cited in the historical literature (e.g., Springer's Evolution: Education and Outreach, "Exploring Mouse Trap History," citing Lewthwaite, Patent No. 221,329) as a curiosity of trap evolution, not as an asserted patent.
3. Anyone litigating this patent would have litigated it between 1879 and 1896, in the circuit courts. Those pleadings are largely not digitized into PACER, CourtListener, or the Unified Patents litigation caselist, and no free source I searched indexes them. I therefore cannot affirmatively rule out 19th-century infringement suits that were never digitized — I can only report that no record of any such suit is discoverable in any of the sources searched.

Caveats

• I could not directly execute a query against the Unified Patents portal search endpoint (my tools retrieve indexed web content); the negative result is based on indexed content of that portal and of CourtListener/PACER-derived material, not a live API query.
• The Google Patents "Cited By (1)/(2)" entry for US20050274057A1 / US7543407B2 (McCulloch, "Humane leg hold trap," filed 2004-06-09) is a citation relationship, not litigation against US 221,329.
• If you need a belt-and-suspenders confirmation, the remaining checks would be a paid Docket Navigator or LexMachina query on "221329" restricted to patent cases, plus a manual NARA/Federal Archives circuit-court search for 1879–1896 — neither of which I can perform here.

Conclusion: No known litigation involves US Patent 221,329.

I'll verify the structured ODP result against public PTAB/CAFC sources before concluding.

Proceedings overview

Total AIA trial proceedings on US Patent 221,329: 0 — the USPTO Open Data Portal structured block in this prompt returns no AIA trial proceedings, and independent web verification (PTAB E2E/PTACTS, PTAB decision compilations, CourtListener/CAFC, and general web) surfaced no petition, no institution decision, no Final Written Decision, no termination, and no Federal Circuit appeal referencing this patent; there is no "breakdown by status" to report because there is nothing to break down. Bottom-line defensive posture: the patent is not "hardened" by surviving IPRs — it is simply untested and untestable in any practical sense. It expired in 1896, and AIA trials before the Board are the wrong instrument for it.

No proceedings to enumerate

Because the canonical list is empty, I cannot supply per-proceeding entries (petitioner, panel, grounds, FWD disposition, settlement, appeal) without fabricating them. Where the requested sub-fields would normally appear, the literal answer is:

• Proceedings overview count: 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials.
• Claim-level outcomes: none exist. Claim 1 (the sole claim — this patent has exactly one omnibus "consisting of" claim, no dependents) has never been construed or adjudicated by the Board.
• Estoppel created: none. 35 U.S.C. § 315(e)(2) is triggered only by a petitioner's IPR that "results in a final written decision" — no FWD, no estoppel, no bar on anyone.
• Reissue / reexamination / interference / derivation: likewise none found. The only post-issuance record event in the file is the 1896-11-04 anticipated expiration (Google's own disclaimer-backed "Expired – Lifetime" status).

What the "221,329" search hits actually are (literal-ID rule)

Consistent with the identification caveat already flagged in the earlier section, every fresh "221329" hit is a different identifier, and none is a PTAB proceeding:

• ANDA No. 221329 — Strides' ANDA in Neurelis, Inc. v. Strides Pharma Global PTE Ltd., D. Del. 1:26-cv-00947 (asserting the '414, '664, '852, '061, '400, '786 and '611 patents on VALTOCOR/diazepam nasal spray). (complaint PDF) Different patent universe, different technology, different tribunal.
• AT 221329 T — an Austrian patent publication in a WO search report. Unrelated.
• US 2005/0274057 A1 / US 7,543,407 B2 (Mcculloch, "Humane leg hold trap") — these are prior-art citations of US 221,329 in later patents, not challenges to it, and neither generated a PTAB filing on the '329 patent.
• Distinguish also the older trap litigation/appellate activity noted in the prior section (e.g., Conibear-type trap validity appeals): those concern different patents and are not cited to, or derivative of, US 221,329.

Why no AIA trial exists (the structural explanation, not just an absence)

1. IPR was the only theoretically available vehicle, and it is a dead letter in practice. Under 35 U.S.C. § 311(c) an IPR petition may be filed after the later of 9 months post-grant or termination of any PGR; for a patent granted 1879-11-04 that window opened in 1879 and never closed. Importantly, expiration alone does not strip Board jurisdiction — the Board may review expired patents because they can still be asserted for past infringement. Apple Inc. v. Gesture Tech. Partners, LLC (Fed. Cir. 2023) (reporter cite: reported in F.4th; verify the exact volume/page before filing anything relying on it); Sony Corp. v. Iancu, 924 F.3d 1235, 1239–41 (Fed. Cir. 2019). So the absence of an IPR is not a jurisdictional statement — it is a statement that no rational petitioner would spend $40K+ challenging a patent whose entire enforceable term ended 1896.
2. PGR was never available. Post-grant review reaches only patents subject to the first-inventor-to-file provisions (effective filing date on or after 2013-03-16). A 1879 filing date is categorically outside it.
3. CBM was never available, and is sunset regardless. The transitional CBM program required a patent claiming a method/apparatus for a financial product or service and expressly excluded patents for technological inventions; a mechanical vermin trap is a technological invention, not a financial-product patent. New CBM petitions also became unavailable after 2018-09-16 (AIA § 18(a)(2) sunset).
4. No live assertion to respond to. Given the 17-year term ending 1896-11-04 and the six-year damages lookback of 35 U.S.C. § 286, there is no recoverable past-infringement window and no prospective injunction. That is the reason no IPR, PGR, or CBM was filed — the same reason none ever will be.

Strategic summary

Claim status: 100% UNTESTED — 0 cancelled, 0 confirmed. Claim 1 (the only claim) has never been before the Board in any AIA proceeding. There are no "surviving claims" to list because none were ever narrowed through IPR/reexam; the claim stands exactly as it issued on 1879-11-04, closed-form ("consisting of"), bottomed on "as shown and described," and limited to the illustrated combination (base-board A rabbeted front and sides, side pieces B B, inclined top C with hole a, bait-rod b c, levers d g, spring E). Anyone asserting it today would be asserting a claim whose construction would turn on a 147-year-old drawing sheet — a fight no one has had to have, because the term is over.

Estoppel landscape: empty. Because there is no IPR FWD, no § 315(e)(1) or (e)(2) estoppel attaches to any party or privy, and no prior-art ground has been "spent." In the abstract, a hypothetical challenger retains every § 102/§ 103 ground and every prior-art reference — including the pre-1879 trap art (e.g., US 218,532, issued 1879-08-12, and the many "similar documents" listed in the file) and the specification's own admission that the trap "is set … in the usual manner." But estoppel is beside the point: there is no case in which to raise anything, and no FWD to link to.

Pattern signals: none. No repeat petitioner, no serial filings, no patent-owner appeal practice, and no defensive aggregator (Unified Patents or similar) in the chain — no aggregator IPR on this number exists. The only recurring "signal" in the file is documentary, not adversarial: the '329 patent is cited as prior art by the Mcculloch humane leg-hold trap family (US 2005/0274057 A1; US 7,543,407 B2). That confirms the patent's role is historical/antecedent art, not an assertion asset.

One flagged non-contradiction: I found nothing contradicting the previously generated sections. The ODP "no proceedings" position and the earlier "no CAFC 2026 docket / no district-court action" finding are mutually consistent, and my searches confirmed the only 2026 "221329" dockets are the unrelated Neurelis v. Strides ANDA matter.

Recommended next steps

• If you have received a demand letter citing US 221,329: do not build an IPR strategy. There is no PTAB record to attack or rely on, and the patent's own expiration (1896-11-04), its 17-year term, and the § 286 six-year damages lookback mean no enforceable infringement liability can exist. Document the expiration date and the single-claim structure and treat any assertion as facially baseless.
• If you nonetheless need a record-based invalidity position (e.g., a declaratory-judgment or sanctions posture), the correct instruments are not AIA trials. An ex parte reexamination under 35 U.S.C. § 302 remains technically available for expired patents (the Office has long conducted them; no amendments or new claims are permitted for expired patents, see MPEP §§ 2249–2250), and invalidity can be litigated in court. But because there is no live controversy, even these routes are almost certainly moot — say so plainly rather than paying for them.
• Trial-stage milestones: none applicable. With zero instituted proceedings, there is no institution-decision deadline, no oral hearing, and no statutory one-year FWD due date to calendar.
• Where I looked, plainly stated: USPTO Open Data Portal structured block (canonical, returns none); PTAB E2E / PTACTS petition search (https://ptacts.uspto.gov/ptacts/ — no petition on this number); USPTO PTAB decisions compilations; CourtListener and CAFC docket sources (https://www.courtlistener.com/ — no appeal); Google Patents record for US221329A. The absence is itself the signal: a patent that expired in 1896 with one omnibus claim will never attract an IPR, and nothing here suggests otherwise.

I'll verify the assignment record and ownership chain with targeted searches before finalizing.

Ownership & Assignment Reconstruction — US Patent 221,329

Scope note: I searched USPTO Assignment Center (successor to EPAS/ETAS at assignment.uspto.gov / assignments.uspto.gov, per USPTO's own notice: "On February 2, 2026 all older web URLs, assignments.uspto.gov and assignment.uspto.gov will no longer be available" — https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1558624](/patent/1558624)/download-documents), Google Patents legal events, and general web/court sources. Result: no assignment records of any kind exist for US 221,329.

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Inventors

• Sole inventor. The specification and claim are executed by one natural person; no joint inventors appear. Witnesses Charles E. Ellsworth and John Thorpe are attesting witnesses only and are not inventors or assignees (1879 specifications routinely carried two local witnesses; there is no evidence either held rights).
• No employer-of-record. The patent carries no "assignor to" line, no corporate designation, and no shop or works name. This is the decisive ownership fact: absent a naming of an assigning company, the inventor personally held whatever rights existed from the outset.
• The "inventors departing the original assignee within 12 months" pattern is inapplicable — there was no original assignee to depart from, and no assignment or termination instrument is of record within any window after the 1879-06-12/13 filing.
• Minor geographic discrepancy (flagged, not resolved): the specification recites "county of Washington" (OCR "NVashington"); modern gazetteers place the hamlet of Fort Miller in the Town of Northumberland in Saratoga County, adjacent to the Washington County line. This is a locating quirk in a 19th-century record and carries no ownership significance.

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Original assignee

None. US 221,329 issued to an unassigned individual inventor.

• The front-page attribution reads "GEORGE W. LEWTHWAITE, OF FORT MILLER, NEW YORK" with no assignee line — consistent with 1879 practice, under which patents issued to the inventor personally until assignment was separately recorded.
• Primary line of business / product in commerce: Indeterminable from the patent record. I found no trade catalog, no manufacturer's mark, no "Lewthwaite" trap company, and no commercial-notice evidence that a trap embodying claim 1 was ever mass-produced or sold. I will not assert that none was made — the record is silent in both directions. What is affirmatively true is that no corporate entity was named as owner, so there is no operating company to characterize as operating, acquired, dissolved, or in bankruptcy.
• Current status: The named owner was a natural person whose rights were extinguished, at the latest, by the anticipated expiration on 1896-11-04 (17-year term; Google Patents legal-status "Expired – Lifetime," which Google itself disclaims as an assumption). There is no successor entity, because there was never a predecessor entity.

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Assignment timeline

The USPTO's Assignment Center returns no records for US 221,329. There is no assignment chain to reconstruct.

Corroborating evidence that this is a real absence and not a lookup failure:

1. Google Patents "Legal Events" for US221329 lists only two events, neither of which is an assignment: 1879-11-04 Application granted / Publication of US221329A, and 1896-11-04 Anticipated expiration. A patent with recorded assignments shows Assignment events in this same feed. This one shows none.
2. No reel/frame, no conveyance type, no assignor, no assignee, and therefore no correspondent of record exists to report. I will not invent a correspondent, and I flag explicitly that the "repeat-player attorney" tell that drives NPE reconstruction is unavailable here for a structural reason: with no recorded conveyance, no attorney filed a recording, so there is no correspondent field to mine.
3. Indexing caveat, stated as a caveat and not as an assignment: pre-1900 transfers were hand-entered in the USPTO's assignment liber volumes, and a meaningful share of 19th-century assignments are not retrievable in the modern electronic index by patent number. So the correct statement is: no assignment is of record and retrievable; absence of a modern hit is not affirmative proof that no deed was ever executed in 1879. Either way, no evidence exists on which to list an assignment, and any rights would have died with the 1896 term.

Other sources cross-referenced with null results: PEDS/ODP-equivalent bibliographic data (no assignee field populated), SEC EDGAR (no entity to search — no corporate assignor or assignee ever appears), and RPX / Unified Patents asserter directories (no entry for this patent number).

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Timeline diagram

timeline
    title Ownership of US 221329
    1879 : Filed by George W Lewthwaite
         : Issued to inventor unassigned
    1896 : Term expires with no recorded transfer

No ownership-change events are plotted because none exist. The two plotted events are the only events in the record.

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NPE / troll-pattern signals

Identification hygiene carried forward from the prior section: the string "221329" in 2026 documents resolves to ANDA No. 221329 in Neurelis, Inc. v. Strides Pharma Global PTE Ltd., D. Del. 1:26-cv-00947 (asserting the '414/'664/'852/'061/'400 patents), and to AT 221329 T, an Austrian publication number. Neither is US Patent 221,329, and neither has any bearing on the signals above.

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Verdict

Insufficient data.

Applying the rubric literally, this patent has no assignment records whatsoever — it issued to an unassigned individual inventor and expired 1896-11-04 with no recorded conveyance, so there is no reel/frame, no assignee, and no correspondent to build an NPE chain from. The rubric's "Insufficient data" catch-all is the only honest fit; the more substantive point is that NPE analysis is inapposite to this asset — every one of the eight signals fails for the same root cause (a single natural-person owner and a term that ended 130 years ago), not because the evidence is thin. Had I found even one assignment, I would report its reel/frame and correspondent as required; I found none, and I decline to fabricate one.

Verify independently at the USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (search by patent number 221329); the legacy landing page https://assignment.uspto.gov/patent/index.html surfaced the same underlying records before its retirement. The only event history in the record is Google Patents' legal-events feed for US221329A: https://patents.google.com/patent/US221329/en.

Compliance note on output order: the task instructions provide for stopping after the Assignment timeline when no records exist. Because the requested output format specifies all sections "in this exact order" and requires a single verdict selection, I completed the remaining sections while making the absence of records explicit at each step rather than omitting them.

I'll run targeted searches on the specific number and on the references that appear in the 221,329 record.

Two quick follow-ups to test whether any pre-June-1879 art discloses the claimed combination.

Prior-Art Analysis — US Patent 221,329 (G. W. Lewthwaite, "Improvement in animal-traps")

Scope note (literal-ID rule): Every search below was run against the exact string 221329 / 221,329. Similar-number hits that surfaced were reviewed only to exclude them and are not reported as this patent: US 1,327,229 (C. A. S. Erickson, animal-trap, 1920), the string "1,327,229" inside that OCR, US 8,856,221 (the "'221 patent" in IPR2015-01181), US 11/146,821 (McCulloch's application number), ANDA No. 221329 (Neurelis v. Strides, D. Del. 1:26-cv-00947), and AT 221329 T (Austrian publication). None is US Patent 221,329.

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1. USPTO record retrieval for 221329

Source: https://patents.google.com/patent/[US221329](/patent/US221329)/en and the scanned original at https://patentimages.storage.googleapis.com/49/7a/c1/480f525442e901/US221329.pdf

This is the single most important finding for your question: 1879 practice did not print prior-art lists on the face of a patent, and this patent's own text names no reference. The specification never says "I am aware that…," never disclaims an earlier patent, and never identifies a "heretofore known" device. Verified against both the Google Patents full text and the patentimages OCR — neither contains a citation table. There is no examiner-cited or applicant-cited prior art of record for US 221,329 itself.

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2. Citations that do exist for 221329 — and why none of them is prior art

Google Patents reports "Cited By (1)/(2)" for US221329A and a "Similar Documents" list. Both were examined literally.

2a. "Cited By" — these are forward citations (they cite 221,329; 221,329 does not cite them)

The relevance of McCulloch is only this: its printed face lists 221,329 as prior art to McCulloch. The examiner's list reads verbatim:

221,329 A * 11/1879 Lewthwaite ...... 43/81

in the U.S. Patent Documents block of US 7,543,407 (asterisk = cited by examiner). Source: https://patentimages.storage.googleapis.com/b1/79/17/cf53a0925946ed/US7543407.pdf

So the relationship is inverted: 221,329 is prior art to McCulloch; McCulloch is not prior art to 221,329. Any table that lists US2005/0274057 or US7,543,407 as "prior art for 221,329" is reading the arrow backwards. This is also confirmed by the Google Patents page structure — the entries appear under "Cited By," not "Patent citations."

2b. "Similar Documents" — a machine-similarity list, not a citation list

Google expressly labels these "similar documents," distinct from its citation and family fields; they are not art of record and carry no citation relationship to 221,329. Applying the date test to each (cut-off: 221,329's filing of June 12/13, 1879, or at most its grant of Nov 4, 1879):

Postdate the filing — temporally incapable of being §102 art: US 243,953 (1881-07-05); US 326,513 (1885-09-15); US 384,415 (1888-06-12); US 409,212 (1889-08-20); US 411,039 (1889-09-17); US 446,119 (1891-02-10); US 450,545 (1891-04-14); US 462,343 (1891-11-03); US 481,707 (1892-08-30); US 499,079 (1893-06-06); US 528,671 (1894-11-06); US 551,412 (1895-12-17); US 571,773 (1896-11-24); US 640,244 (1900-01-02); US 659,932 (1900-10-16); US 715,829 (1902-12-16); US 734,413 (1903-07-21); US 1,017,605 (1912-02-13); US 1,046,799 (1912-12-10); US 1,080,623 (1913-12-09); US 1,160,872 (1915-11-16); US 1,226,517 (1917-05-15); US 1,290,697 (1919-01-07).

Predate the filing — the only two candidates worth analyzing: US 91,427 (1869-06-15) and US 218,532 (1879-08-12).

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3. The two date-qualifying references — §102 analysis on the single claim

The claim is one omnibus closed claim:

"An animal-trap consisting of the base-board A, rabbeted at front and on the sides, the side pieces, B B, the inclined top C having hole a′, the bait-rod b′ c′, the levers d′ g′, and the spring E, as shown and described."

Two consequences drive the §102 result:

1. Anticipation requires a single reference disclosing every recited element in the claimed cooperation — here: rabbeted base-board A + side pieces B B + inclined top C with bait hole + bait-rod/hook b′ c′ + two levers d′ g′ with their staples + coil spring E whose loop runs along the sides and front and drives the animal onto sharp edge k′.
2. Because the claim is in "consisting of" form (and is further bottomed on "as shown and described"), a prior-art device containing additional unrecited structure would not literally anticipate a closed claim of this type. Applied to 1879 subject matter, this makes anticipation extremely difficult — the claim is effectively limited to the illustrated combination.

(Rev. Stat. §4886 note / temporal law.) 221,329 was granted in 1879, so 35 U.S.C. §102 was not the operative text; the governing provision was Rev. Stat. §4886 (Act of July 8, 1870, §24), the direct ancestor of pre-AIA §102(a)/(b), which barred patenting where the invention had been "patented or described in any printed publication … before his invention." Modern §102(e) (prior-filed, later-published applications) was not enacted until 1952 and cannot be applied to 1879 facts; §103 likewise did not exist. I therefore apply §102 conceptually, and flag that both anticipations below fail.

Reference A — US 218,532 A (Hooker)

Reference B — US 91,427 (Flanders)

Candidate reference not of record (disclosed for completeness, not relied on)

US 179,788 (Hayden), July 11, 1876 — a pre-1879 animal-trap patent that surfaced as category "X" art in the international search report for WO 03/009683 A1 (a spring-biased-closure trap case). It predates 221,329 and would be §102-eligible on date, but it is not a citation of record in 221,329, and I did not retrieve its specification, so I cannot describe its disclosure or opine on anticipation. Similarly, other pre-1879 trap patents surfaced incidentally in searching (US 53,164, Melone, 1866-03-13; US 89,300, Fenn, 1869-04-27; US 91,744, Henert, 1869-06-22) — none is a citation of record for 221,329, and none was retrieved in full. I am not representing any of these as anticipating art.

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4. Consolidated §102 answer table

Anticipation conclusion: no reference of record anticipates the sole claim of US 221,329, and no reference in the entire retrieved record has been shown to disclose the claimed combination.

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5. Explicit uncertainty flags

1. No prior art exists "of record" for this patent in the modern sense. If your workflow expects a "References Cited" block, one does not exist and should not be populated with forward citations or similar-document lists.
2. The McCulloch citations run the wrong way. This is the most likely source of error in a downstream prior-art table — the arrow must read 221,329 → McCulloch, not McCulloch → 221,329.
3. Date conflict in the primary document (filed June 12 vs. June 13, 1879) remains unresolved; both dates are before Aug 12, 1879, so the Hooker analysis is unaffected either way.
4. I could not query USPTO PatentCenter or the USPTO full-text search API directly, nor paid databases (Docket Navigator, LexMachina). My retrieval is of Google Patents' mirror of the USPTO record plus Espacenet and patentimages. A PatentCenter "References Cited" confirmation would be belt-and-suspenders, but for a one-page 1879 patent with no citation table I have no reason to expect one.
5. 1879 law, not §102, governs. I applied Rev. Stat. §4886 and modern §102 principles comparatively, and flagged the modern doctrines (§102(e), §103) that cannot be retrofitted to this grant.
6. US 179,788 and the other pre-1879 traps noted in §3 are candidates I surfaced but did not verify; treat them as leads, not findings, until their specifications are pulled.

I'll ground this analysis by pulling the actual disclosures of the only references on this page that can even qualify as prior art, then triage the rest.

Now let me pin down the Conibear trap validity appeal that surfaced (a directly on-point obviousness-in-trap-art precedent), so I can cite it accurately rather than guess.

Obviousness Analysis — US 221,329 (Lewthwaite), 35 U.S.C. § 103

Note: this section builds on the claim construction and reference triage already in the Patent Summary and Litigation Summary above; I do not restate the bibliographic core. Two flag-worthy items first.

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0. Threshold: two corrections before any § 103 analysis is performed

(a) § 103 did not exist in 1879. US 221,329 issued November 4, 1879 and expired November 4, 1896. Obviousness as a statutory test arrived with the Patent Act of 1952, Pub. L. 82-593, 35 U.S.C. § 103, effective January 1, 1953 — 57 years after this patent died. The law actually applicable to it was Rev. Stat. § 4886 (novelty bars) plus the judge-made "invention" requirement of Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248 (1850), later hardened into the "flash of creative genius" test of Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84 (1941). That standard was substantially more patentee-friendly than modern § 103. So a finding of "obvious under § 103" is not a statement that this claim was invalid when it lived. Everything below is a retrospective hypothetical applying Graham v. John Deere Co., 383 U.S. 1 (1966), and KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), to a 19th-century grant.

(b) Date inconsistency in this record. The task header states "Current Date: April 26, 2026," while the previously generated sections and the Google Patents fetch stamp both say 2026-09-30. I flag rather than resolve it; nothing in the analysis turns on it.

Practical consequence: no § 282 presumption of validity attaches (35 U.S.C. § 282), no infringement or IPR is possible, and there is no challenger with a burden of proof. This is a pure paper exercise.

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1. Triage of the "Prior Art" section of the page — the single most important finding

The Google Patents page does not present a § 102 prior-art search report. It presents three things, only one of which can cite any prior art:

Date triage of the 25 "Similar Documents":

Ineligible (all post-date the Nov. 4, 1879 grant): US 243,953 (1881); US 326,513 (1885); US 384,415 (1888); US 409,212 (1889); US 411,039 (1889); US 446,119 (1891); US 450,545 (1891); US 462,343 (1891); US 481,707 (1892); US 499,079 (1893); US 528,671 (1894); US 551,412 (1895); US 571,773 (1896); US 640,244 (1900); US 659,932 (1900); US 715,829 (1902); US 734,413 (1903); US 1,017,605 (1912); US 1,046,799 (1912); US 1,080,623 (1913); US 1,160,872 (1915); US 1,226,517 (1917); US 1,290,697 (1919).

Bottom line: the entire § 103 prior-art universe available from this page is two references — US 91,427 and US 218,532. This is the honest answer, and it is the answer most likely to be gotten wrong by treating Google's "similar documents" as an examiner's citation list.

On US 218,532's contingent status. Hooker filed March 6, 1879 — roughly three months before Lewthwaite's June 12/13, 1879 filing (that one-day conflict is already flagged above) — and issued August 12, 1879, before Lewthwaite's November 4 grant. Whether it is prior art turns on Lewthwaite's actual date of invention, which is not of record:

• If Lewthwaite invented after March 6, 1879 → US 218,532 is prior art as of its filing date under pre-AIA § 102(e). This is the more likely case given the three-month gap.
• If Lewthwaite invented before March 6, 1879 → it is not § 102(a) art, and § 102(e) also fails.
• Under the law actually in force in 1879 (Rev. Stat. § 4886), there is genuine doubt whether an intervening patent issued after the applicant's invention but before his filing was a statutory bar at all. I flag this rather than resolve it; the 1879 statute's "known or used" and two-year clauses were not coextensive with modern § 102(e).

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2. The claim as the unit of analysis

The single omnibus claim's elements were itemized in the Patent Summary. For § 103 mapping I use those groups as E1 base-board A (rabbeted front and sides, raised central platform, sharp front edge k), E2 side pieces B B, E3 inclined top C with bait hole a, E4 bait-rod b with hook c, E5 levers d and g, E6 coiled spring E with square loop along sides and front.

Two constructional points that drive the whole analysis:

• The claim is in closed "consisting of" form but terminates "as shown and described." A modern examiner would likely treat that terminal phrase as indefinite under § 112(b) (19th-century omnibus format; see MPEP § 2173.05(s) on reference to figures/description — noted as a practice observation I have not re-verified against the current MPEP). For § 103 purposes I construe the claim as importing the illustrated embodiment, which makes it narrower but better defined: brace D, staples f/h, and sharp edge k come in.
• Because it imports the illustrated structure, the specification is the map of what must be found in the art — which makes the patentee's own admissions unusually powerful (§ 5 below).

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3. What each eligible reference actually discloses

US 91,427 — A. C. Flanders, Owatonna, Minnesota, June 15, 1869 (Google Patents; Espacenet claims). Notably, Flanders uses the same reference letters A, B, C as Lewthwaite:

• "A is a base-board, which supports an upright board, B, and an inclined wooden strip, C." → base + upright + incline, the exact structural triad of E1/E2/E3.
• "D is the bait-hook, extending through a slot in the upright plate B, where it is pivoted … its rear end being formed into a loop, d." → bait hook on a pivoted member (cf. E4).
• "E is a rod, pivoted to the incline C, and extending down slightly below the loop d, so that by depressing the latter a little, the lower end of the rod may be inserted into the loop … The upper end of the rod is bent down … to form a catch for setting the trap." → a pivoted catch directly engaging the bait hook.
• "F is a lever, or arm, pivoted between lugs f f, attached to the upper side of the incline C … capable of being bent back … or of being, by the operation of a spring, S, thrown forward." → a spring-loaded lever pivoted on the incline, with "a hook, e, which engages with the rod E, to set the trap."
• Stated advantages: the arrangement gives "great velocity at the commencement of its movement, so as to insure the catching of the animal, and great power toward the end … so as to insure the killing," and once fired, "the draught upon the cord … only serves to lock the spring-arm down, and prevent the escape."

So Flanders teaches a two-link, pivoted, spring-loaded trigger train mounted on an incline — functionally the c-d-g chain of E4/E5 — plus the base/upright/incline trio. Its catching mechanism (slip-noose) and its spring-arm type differ.

US 218,532 — William G. Hooker, Abingdon, Illinois, filed March 6, 1879, issued August 12, 1879 (Google Patents). A single-piece wire trap: loop/eye b, a sharpened spur c, a coiled spring d, a bow g, and "a trigger having an abutment and an extension up into the bow." Field: "catching small animals, such as rats, gophers, and minks … by setting the trap in the holes and runways frequented by such animals." Classification A01M23/24 (spring traps). Supplies E6's coiled spring and a sharp animal-engaging point; supplies nothing of the housing.

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4. Primary combination: US 91,427 in view of US 218,532

Gap analysis after Flanders:

Motivation to combine (why a PHOSITA would):

1. Same field and same problem. Both are A01M23/24 spring traps for the same vermin (rats/vermin); Hooker expressly names rats, Flanders' trap is an all-purpose vermin trap.
2. Same stated goal. Flanders wants "velocity at the commencement … to insure the catching" and "power toward the end … to insure the killing," and a self-locking action. Lewthwaite's object is identical in substance ("strong, efficient, and durable … for rats"), and its claimed advantage (spring presses the animal "down upon the sharp edge k … so that he cannot get away") is the same result.
3. Predictable substitution. Swapping a spring-arm for a coil spring as the energy store of a trap is the paradigm of a predictable mechanical substitution — one known element for another, each performing its known function (KSR, 550 U.S. at 415–17).
4. Finite solution set. The trap art offered a small, enumerated menu of trap motors (spring-arm, coil, bow, jaw) and catches (noose, hook, jaw); the claimed arrangement is one of them, giving a reasonable expectation of success — the "obvious to try" rationale.

KSR rationales that map cleanly onto the residual gaps:

• Combination of familiar elements according to known methods yielding predictable results (KSR, 550 U.S. at 416) — Flanders' base/upright/incline + Hooker's coil spring.
• Mere duplication of parts — one upright board B → two side pieces B B. Duplication of a known part carries no patentable weight absent a new or unexpected result. (I cite In re Harza, 274 F.2d 669 (CCPA 1960) for this proposition, with moderate confidence in the citation; the same proposition appears in MPEP § 2144.04.)
• Obvious design choice / change in shape or proportion — rabbeting the front and sides to leave a raised central platform and a thin front lip (k) is a standard board-joinery step; its residue is simply the sharp edge the patentee relies on. MPEP §§ 2144.04, 2144.05.
• Known technique to improve a similar device in the same way (KSR) — adding lateral walls to block approach and light-admitting gaps so the bait shows from the front is a spatial arrangement whose function follows directly from the geometry. That the patentee recognized the light-admitting benefit of the B–D spacing is an appreciation of an inherent property of the old structure, not a new structure.
• The "more unstable" trigger is mere optimization. The specification concedes lever g "mak[es] the holding of the spring more unstable than if the hook and lever d were directly connected with c." Tuning trigger sensitivity by inserting one more pivot in a latch train is optimizing a known parameter, where the result (quicker tripping) is the expected result of the change.

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5. The patentee's own specification as admitted prior art — the sharpest § 103 tool here

Two sentences in the Lewthwaite specification are, in modern practice, effectively admissions usable for § 103 (the principle that an applicant's statement that a feature is conventional constitutes admitted prior art; cf. In re Nomiya, 509 F.2d 566 (CCPA 1975) — cited with moderate confidence):

1. "The trap is set — the spring raised and held in the usual manner, by the engagement of the hook c, hook and lever d, and lever g, as shown in the drawings." The setting/holding function is admitted to be "usual."
2. "or the strap can be made without the lever g and the lever d, and allowed to connect with c."

Point (2) is decisive against any non-obviousness argument resting on the two-lever linkage: the patentee himself discloses the one-link version and the two-link version as interchangeable. That forecloses the contention that lever g is a critical or unexpected element, and it establishes as of the filing that the number of links in the trigger train was regarded as a matter of design choice. Where the patentee's own disclosure supplies the alternative, KSR's "predictable variation" rationale applies with particular force.

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6. Where the § 103 case is genuinely weak — stated fairly

I do not think this is a clean case, and the negative side deserves equal space:

1. No reference discloses the claimed housing as an integrated whole. Neither Flanders nor Hooker shows a rabbeted base + two side boards + inclined top carrying a bait hole, where the side walls simultaneously (i) block lateral access and (ii) leave gaps admitting light to the bait. That dual-function arrangement is a specific stated design insight, and the page contains no reference that teaches it. KSR would not necessarily rescue a combination where the primary reference's incline is a lower support strip rather than an enclosing top.
2. Sharp edge k under the spring loop is not disclosed. Hooker's spur is a sharpened wire end on a one-piece wire trap — a different mechanism. Flanders has no counterpart. The claimed "press the animal down onto the sharp edge of the base" cooperation is the element the § 103 case handles most weakly, and it is arguably the functional heart of the contribution.
3. Appellate trap-art precedent counsels caution. In Woodstream Corp. v. Herter's, Inc., 446 F.2d 1143 (8th Cir. 1971) (CourtListener; Justia), the Eighth Circuit reversed a district court's obviousness invalidation of the Conibear and Lehn traps, holding that "defendants' case offers no explanation how, without hindsight, one having skill in the art would ascertain the mechanical elements he should draw from scores of existing traps, antique traps or traps disclosed in the Patent Office," and that the plaintiff prevailed on § 282 plus secondary considerations (commercial success, long-felt need, failure of others). Its factual findings rest on exactly the kind of record my analysis lacks. Caveat: Woodstream is pre-KSR and its reasoning turns on the defendants' evidentiary failure and the presumption of validity, not on any intrinsic merit in trap art; KSR's "expansive and flexible" approach (and Graham's own "better mousetrap … long path to tread" admonition, quoted but distinguished there) would substantially blunt it today.
4. No expert evidence and no secondary considerations. Nothing in this record shows commercial success, long-felt but unsolved need, failure of others, copying, or unexpected results for the Lewthwaite trap. Conversely, nothing shows the art was saturated with equivalents either. My analysis is a document-based screening opinion, not a validity determination.
5. The prior-art base is artificially thin because the page's list is a similarity list, not a search report. A genuine pre-1879 § 103 analysis would also canvass the large contemporaneous body of break-back/snap and noose trap art (classification A01M23/30 was applied to this very patent), none of which I can responsibly characterize without retrieval.

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7. Conclusion and confidence

Combinations that would render claim 1 obvious (ranked):

Overall (retrospective, modern § 103/KSR lens): claim 1 would more likely than not be held obvious over US 91,427 in view of US 218,532, with the d/g linkage and the "more unstable" sensitivity being design choices and the coil spring being a predictable substitution. Under the law actually in force in 1879–1896 (Rev. Stat. § 4886 plus the Hotchkiss "invention" standard), the claim was probably valid, and the two standards should not be conflated.

Confidence: HIGH that only US 91,427 and US 218,532 of the listed documents are even eligible prior art · MODERATE that the combination renders claim 1 obvious · LOW-MODERATE as to how any tribunal would weigh the missing housing/sharp-edge teaching absent expert and objective evidence.

What would change this answer: (i) the actual drawings of US 221,329 (absent from the text I have), to confirm the housing geometry and the square-loop spring; (ii) Lewthwaite's invention date, to settle US 218,532's eligibility; (iii) the patent's original face "References Cited," which the OCR excerpt does not show; (iv) retrieval of pre-1879 break-back trap art, which would likely strengthen the obviousness case materially.

One research lead, flagged as unverified and not relied upon: the Nebraska State Historical Society mouse-trap study surfaced in search identifies "Family, Abingdon Trap Co., Abingdon, Ill." and "Catchemaltee, Animal Trap Co., Abingdon, Ill." as commercial traps — Abingdon being Hooker's town and the town associated with the Abingdon Trap Company. If Hooker-type coil-spring traps were in commercial use in the late 1870s, that would be relevant § 103 objective evidence about the state of the art. I have not verified any connection between Hooker's 1879 patent and those products, and it says nothing about Lewthwaite's trap.