US 133556

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

US Patent 133,556 — Search Report and Summary

Scope of search performed: USPTO (via Google Patents mirror of the printed specification), Google Patents "Similar Documents" table, and open-web searches for a CAFC 2026 docket citing 133556. Searches were run on the literal string "133556"/"133,556." Results returned no CAFC docket, no litigation record, and no assignment record for this patent.

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1. Bibliographic data

Discrepancy flags (not auto-corrected):

• Body of specification: "JAMES L. ANDERSON." Signature: "JAMES LEWIS ANDERSON." The full name is inferable but is stated only in the signature.
• The front-matter city is OCR'd "BUOYRUS"; the specification body spells it "Bucyrus."

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2. Abstract

There is no abstract. US 133,556 issued in 1872, roughly eight decades before abstracts became a statutory requirement of US patent documents. The "Definitions" section on the Google Patents page is not an abstract — it is a verbatim transcription of the specification's opening figure descriptions and invention statement. Quoting it as the de facto summary:

"This invention relates to a new means for locking the switch-levers on railroads automatically and eti'ectively [sic]. The invention consists in providing the switch-lever with an up-and-down adjustable transverse bolt, which will drop into notches of the arcs between which the lever can be moved. The invention also consists in combining with the aforementioned key a projecting ear on the lever, a vertical drop-bolt for looking [sic] into it, and an ordinary key for raising the drop-bolt and liberating the lever when desired."

(OCR artifacts in the source — "eti'ectively," "looking" for "locking," "011'" for "off," and stray commas replacing letter references — are reproduced as found.)

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3. Structural elements disclosed

• A — the switch-lever, pivoted in a stationary frame B
• B — stationary frame
• C C / O O — two arcs rigidly connected to frame B, between which the lever is guided; their upper edges are notched at each position where the lever must be locked
• D — a transverse bolt fitted through lever A, adjustable up and down in a slot a of the lever
• E — a box or case fastened to the side of one arc, containing a drop-bolt b and a keyhole for a key (key not illustrated)
• c (OCR'd as "0") — a projecting ear formed on lever A

Operation: As the lever is swung into line with a set of arc notches, bolt D drops by gravity into the notches, automatically locking the lever to the arcs. When the lever reaches mid-span between the arches (or wherever the rails are in the normal position), it also aligns with case E and is moved toward it into the arc recess, so the ear c enters the box beneath bolt b. Bolt b then drops into a notch in the ear, "double locking" the lever. A key raises bolt b off the ear; release requires that bolt D also be raised out of its notch.

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4. Claims — plain-language overview

There are two claims, both drafted as independent claims under modern nomenclature (claim 2 does not refer back to claim 1). Note that the independent/dependent distinction is a present-day characterization; the 1872 claim format did not use it.

Claim 1 — the automatic gravity bolt (subcombination).
What is claimed is the transverse bolt D, fitted through the vertical slot of the lever A, for locking into the notched arcs. In plain terms: a sliding bolt carried in a vertical slot in the switch lever, which falls into notches cut in the stationary arcs to hold the lever in position.

• OCR variance to flag: the claim recites "notched arcs G G," while the specification body calls the arcs "O O" and "C C." I am reporting the identifiers literally rather than reconciling them.

Claim 2 — the combination lock (ear + drop-bolt + key).
What is claimed is the combination of lever A and bolt D with the ear c and drop-bolt b, operating as specified. In plain terms: the overall assembly in which the lever's projecting ear slides under a key-operated spring/gravity drop-bolt in a lock box, so the lever is secured both by the gravity bolt in the arc notches and by the keyed drop-bolt engaging the ear — a two-stage lock that can be released only by simultaneously lifting the keyed drop-bolt and the gravity bolt.

Claim-type note: both claims are mechanical apparatus claims; neither recites a method step or a means-plus-function limitation.

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5. Prior art / related documents (as listed by the source, not necessarily examiner citations)

Google Patents lists these as "Similar Documents," not confirmed prior-art references cited against the application:

• US 132,597 (1872-10-29) — Improvement in switch-locking devices
• US 113,112 (1871-03-28) — Improvement in railway-switch locks
• US 130,487 (1872-08-13) — Improvement in railroad switch-stands
• US 98,472 (1870-01-04) — Improved switch-stand for railways
• US 6,394 (1849-04-24) — Method of fastening railroad-switches

A separately returned document, US 7,176 (Slaight, 1850), is a keyed switch-lock with a guard plate — topically adjacent, but it is not listed by the source as linked to 133,556, and I will not assert a citation relationship that the source does not show.

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6. CAFC 2026 docket check

No results. I found no Court of Appeals for the Federal Circuit docket, opinion, or order in 2026 (or any year) involving US 133,556. Two independent reasons make such a docket implausible regardless: (a) the patent expired December 3, 1889; and (b) the Federal Circuit was not created until 1982, so any 1872-era appeal would have run through entirely different courts. I state affirmatively that I found no CAFC 2026 activity — not that none exists in some unindexed form.

Caution on bare-number searching: the literal string "133556" also matches unrelated documents — WO 2015/133556, WO 2016/133556, and PCT/CN2021/133556 — none of which are US 133,556. Anyone running a bare-number query should not conflate them.

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7. Explicit uncertainty statements

• Filing date: unknown. Not stated in any source I retrieved. Do not infer it from the 1872-12-03 grant date.
• Assignee: none recorded, which I read as an accurate negative rather than a search failure — assignee fields were commonly blank on 1870s US patents and the printed specification shows no assignment. I did not, however, search the USPTO Assignment database directly (the Google Patents front matter shows an Assignment link but no assignment data).
• Inventor name is stated two ways in the same document ("James L. Anderson" / "James Lewis Anderson"). I have not resolved which is authoritative.
• Claim 1 arc identifier conflict ("G G" in claim vs. "O O"/"C C" in description) is left unresolved.
• I did not independently verify the grant against the USPTO PatentCenter or the printed Official Gazette; the specification text and dates above are taken from the Google Patents transcript at https://patents.google.com/patent/[US133556](/patent/US133556)/en.

I'll search for litigation records involving US Patent 133,556.

Litigation search results — U.S. Patent No. 133,556

Bottom line: No litigation involving U.S. Patent No. 133,556 was found. I could not identify any plaintiff, defendant, jurisdiction, case number, filing date, or outcome, because no such case appears in the sources searched.

What was searched

Why this is the expected result — and the important caveat

The patent's own record forecloses modern litigation. Per the Google Patents record at https://patents.google.com/patent/US133556/en, US 133,556 ("Improvement in railroad-switch locks," James L. Anderson, Bucyrus, Ohio) issued December 3, 1872, with an "Anticipated expiration" of December 3, 1889 and a legal status of "Expired – Lifetime." The patent has been expired for roughly 137 years. An expired patent cannot be asserted in an infringement action, and the statutory term was long ago exhausted.

But the databases named in your instruction cannot see this era anyway. Unified Patents' litigation portal, PACER, and CourtListener/Recap are built from electronic dockets and modern reported opinions; PACER's coverage begins only in the late 1980s–1990s, and Unified Patents tracks post‑2010s docket activity. A case from 1872–1889 would be litigated in state courts or in the U.S. circuit courts (the pre‑1912 system), would be reported if at all in volumes such as Fed. Cas. or F. Rep., and would not appear in any of these modern systems. So my negative result is strong evidence that no litigation exists in the sources you named, but it is not proof that no suit was ever filed in the 1870s or 1880s. That question could only be answered by a manual search of West's Federal Cases (the Federal Reporter predecessor) and 19th‑century circuit court equity records — which I cannot complete through the tools available here.

Note on identifier discipline

Per your strict rule, I did not auto‑correct or substitute numbers. Several searches returned superficially similar but distinct identifiers, and I am deliberately not reporting them as litigation for US 133,556:

• U.S. 7,796,133 — VIZIO/NVIDIA unified shader PTAB and ITC matters (a different patent entirely)
• ITC Inv. No. 337‑TA‑556 and 337‑TA‑617 — investigations, not patents
• NO 133556 B (Ingvar Andersson, wall-element holder), WO 2016/133556, WO 2012/133556, HU 133556 — foreign documents sharing the numerals only
• "the '556 Patent" in Rovi/Comcast and Chandler‑Evans — short-form designations of unrelated patents (e.g., 6,728,967‑family, 2,414,322‑era carburetor patents)

Conclusion

No known litigation involves U.S. Patent No. 133,556. For any case to be reported, you would need: plaintiff, defendant, jurisdiction, case number, filing date, and status — I have none of these, and I will not fabricate them. If you need to rule out 19th‑century circuit court infringement actions with finality, the next step is an offline search of Federal Cases and the National Archives circuit court equity dockets for the Northern District of Ohio (1872–1889), which is outside what these databases cover.

Proceedings overview

Zero AIA trial proceedings. The USPTO Open Data Portal ("PTAB proceedings on file") returns no IPR, PGR, or CBM petition against US 133,556 as of the most recent ingest, and my web checks surfaced no older or recently-filed proceeding that ODP has missed. Breakdown by status is therefore: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0. The defensive posture for a defendant is not "hardened patent" and not "claims canceled" — it is "there is nothing to defend against on the merits of an AIA trial, because this patent has been expired since 1889-12-03." US 133,556 issued 1872-12-03, carries an "Anticipated expiration" of 1889-12-03 in the ODP record, and has a legal status of "Expired - Lifetime." Any assertion of claims 1 or 2 of this patent today would fail on its face before any PTAB or district-court invalidity question is reached.

No proceeding exists — US 133,556 (Anderson, "Improvement in railroad-switch locks")

• Type: Not applicable. IPR was created by the Leahy–Smith America Invents Act, Pub. L. 112-29, §§ 6(a), 311–319, and available only for petitions filed on or after 2012-09-16; PGR likewise 2012-09-16, and CBM review ran 2012-09-16 through 2020-09-16. No such vehicle was filed here.
• Filed: N/A — no petition on file.
• Status: N/A (no proceeding). The patent's own status is verbatim "Expired - Lifetime", with an anticipated expiration of 1889-12-03.
• Judge panel: N/A — no APJ panel ever assigned.
• Petition grounds: N/A. For context, the only claims that ever existed are claim 1 ("The transverse bolt D, fitted through the vertical slot of the lever A to lock in the notched arcs G G, as set forth.") and claim 2 ("The combination of the lever A and bolt D with the ear C and drop-bolt b, all operating as specified.").
• Institution decision: N/A.
• Final Written Decision: N/A — no FWD, so no claim-level verdict exists. I will not attribute a cancellation or a survivorship holding to any claim, because none was ever made.
• Settlement / termination: N/A.
• Appeal: N/A. No FWD means no CAFC appeal of an FWD; I found no Federal Circuit or CourtListener record of an appeal involving this patent.
• Defensive value: Total. The patent is in the public domain, so there is no live claim to infringe and no PTAB estoppel to worry about. If a demand letter cites "US 133,556," that is a strong tell that the sender has done no diligence — and if the letter cites claims 1 and/or 2 as live, the sender is citing claims from a patent that expired in the 19th century.

Strategic summary

Claim status. Untested, not cancelled. It is important not to misread "no IPR" as "claims survived IPR." Claims 1 and 2 of US 133,556 were never challenged at the PTAB because there is no PTAB jurisdiction that was ever exercised over a patent of this vintage — the AIA trial regime did not exist during the patent's life or for the following 123 years, and the patent had already been expired for 123 years when the first IPR was ever instituted. The claims are best characterized as expired and unenforceable for any post-1889 conduct, not as "sustained."

Estoppel landscape. There is none. 35 U.S.C. § 315(e)(2) estoppel attaches only to a petitioner that obtains an FWD; with zero proceedings there are zero estops, and no party is barred from raising any prior-art ground. That said, the estoppel question is academic. The prior-art landscape around this patent is dense: the Google Patents "Similar Documents" list includes US 11,3112 (1871-03-28, "Improvement in railway-switch locks"), US 130,487 (1872-08-13, "Improvement in railroad switch-stands"), US 132,597 (1872-10-29, "Improvement in switch-locking devices"), and US 124,118 (1872-02-27, "Improvement in railway switches"), among many others. Several of these predate the 1872-12-03 issuance of 133,556 and would be squarely available as § 102(a)/(b) art under the pre-AIA statute that governs — a useful hypothetical only, since enforceability fails long before validity is reached.

Pattern signals. None of the ordinary IPR-trial signals are present: no serial petitioner, no Unified Patents or other defensive aggregator in the chain, no PTAB appeal activity, no POP/Director Review. There is no family beyond the single US filing (Family ID 2202972; one application, US133556D, one country). The only forward citation trail in the ODP record is the standard "Similar Documents" cluster of 19th-century switch and switch-lock patents; none of it evidences a modern assertion campaign. Note also that the publication-number string "133556" is heavily reused across jurisdictions and years (e.g., WO 2012/133556, WO 2015/133556, Norwegian patent NO 133556B, Hungarian registration 133556, and TI's application Ser. No. 10/133,556 which issued as US 6,620,692) — none of these are the same patent, and any search hit of that kind should not be mistaken for an IPR docket.

Recommended next steps

• No PTAB activity exists, and none can exist for this patent. Say that plainly in any client memo, and treat the absence as dispositive rather than as a signal that IPRs are simply "not yet indexed."
• If you are a defendant and a demand letter cites US 133,556, do not brief invalidity. Point to the ODP record showing "Expired - Lifetime" / anticipated expiration 1889-12-03 (https://patents.google.com/patent/[US133556](/patent/US133556)/en) and to the 35 U.S.C. §§ 311–319 date scheme (AIA trial practice available only for petitions filed on or after 2012-09-16). There is no FWD to link because there is no FWD; the correct citation for the disposition is the patent's own expiration.
• If someone purports to quote an FWD verdict on this patent, treat it as fabricated unless they can produce a proceeding number that resolves in the PTAB's public systems — PTAB E2E (https://ptacts.uspto.gov/ptacts/) and the PTAB Decisions collection (https://www.uspto.gov/patents/ptab/decisions). I could not locate any such record, and the ODP structured data affirmatively returns none. Likewise, CourtListener (https://www.courtlistener.com/) shows no Federal Circuit appeal of an FWD on this patent.
• Do not confuse similarly numbered documents. "133,556" as a US patent number, as a WO publication number, as a Norwegian/Hungarian registration number, and as a Texas Instruments application serial number (10/133,556 → US 6,620,692) are unrelated. Verify by issue date (1872-12-03) and title ("Improvement in railroad-switch locks") before crediting any search result.

Confidence note: I have high confidence in the zero-proceeding conclusion, grounded in the structured ODP block plus the post-2012 availability of AIA trials against a patent that expired 1889-12-03. I did not locate any PTAB Final Written Decision, institution decision, settlement, or CAFC appeal for US 133,556, and I have not invented any proceeding numbers, panels, or claim-level outcomes to fill the template.

I'll verify the assignment record and inventor history before drawing conclusions.

Ownership analysis — US Patent 133,556 ("Improvement in Railroad-Switch Locks")

Scope note / method. I queried Google Patents (the full text you supplied, fetched 2026‑09‑26) and ran targeted web searches against the USPTO assignment infrastructure and 19th‑century patent records. I could not execute a live, credentialed query of the Assignment Center's underlying API — it is a JavaScript application and returned no direct record payload to my tooling. The findings below therefore rest on (a) the authoritative patent text, (b) the Google Patents legal‑events record, and (c) what is knowable about the coverage window of the USPTO assignment database. I have flagged that limitation rather than papering over it.

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Inventors

• The signature block reads "JAMES LEWIS ANDERSON", while the heading and the To all whom it may concern line read "JAMES L. ANDERSON." These are almost certainly the same person (the "Lewis" middle name would explain the initial), but the discrepancy is in the original text and I am recording it rather than silently reconciling it.
• Witnesses of record: J. G. Hall and S. R. Harris. Both are witnesses to the specification, not assignees or attorneys of record.
• Unusual patterns: none of the classic modern ones apply. There is no evidence of co‑inventor departure, no team of inventors, and no corporate context to measure departure against. The single‑inventor, individually‑owned model is entirely typical of 1872 practice — in that era most patents issued directly to the inventor, and employee‑invention assignment obligations were not yet the norm they became after the 1880s corporate R&D build‑out.
• Bucyrus, Ohio was a rail‑served Crawford County town in a period of heavy railroad construction, so an independent mechanic or railroad employee inventing a switch lock is contextually plausible. I could not verify any specific employer with high confidence and will not guess at one.

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Original assignee

None — the patent issued to the inventor as sole owner.

The front matter on US 133,556 contains no assignee designation. Contrast this with the convention of the era, in which an assigned patent was printed with "assignors to ___" language. For comparison, the Commissioner of Patents' annual lists from the same period show entries such as "Cram, Alonzo W., and William B. Dunbar, assignors to Alonzo W. Cram, Chicago, Ill. — Switch‑lock" (No. 116,416, June 27, 1871). US 133,556 carries no such notation, which is affirmative evidence that no assignment was made at or before issuance.

Consequently the requested fields cannot be populated:

• Entity on the issued patent: none (individual ownership: James L. Anderson).
• Did they ship a product embodying the claims? Not determinable. No corporate manufacturer is identified, and no commercial embodiment was located.
• Primary line of business: not applicable — the owner was a natural person, not an entity.
• Current status: the owner is a natural person who would have been an adult in 1872; presumed deceased. The patent itself expired 1889‑12‑03 per Google Patents' legal‑events entry ("Anticipated expiration"), which is the correct 17‑year term measured from the December 3, 1872 grant.

Terminology trap worth naming: Google Patents indexes this record as both US133556A and US133556D. The "D" suffix here is a Google Patents internal application/family identifier, not a design‑patent designation. US 133,556 is a utility patent (railroad switch lock). Do not carry US133556D into any downstream docket as a design patent.

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Assignment timeline

The USPTO Assignment Center contains no recorded assignment records for US Patent 133,556. There is no reel/frame, no conveyance type, no assignor, no assignee, and no correspondent of record for this patent to report.

Two independent reasons explain this, and the second is the methodologically important one:

1. The patent was never assigned, so far as the record shows. It issued to Anderson individually with no assignee designation, and Google Patents' legal‑events block lists only issuance (1872‑12‑03) and expiration (1889‑12‑03) — no reassignment events of any kind.
2. The USPTO assignment database physically cannot speak to this patent's era. The Assignments on the Web / Assignment Center database covers assignments recorded with the USPTO since August 1980. US 133,556 expired on 1889‑12‑03 — roughly 91 years before the coverage window opens. A null result from Assignment Center is therefore not probative evidence about 19th‑century chain of title; it is an artifact of database scope. Any assignment Anderson made in, say, 1874 would have been recorded at the Patent Office in a paper liber that is not in the electronic system.

If a definitive 19th‑century chain of title were required (e.g., for a historical or chain‑of‑title‑only purpose), the correct next step is a manual paper‑record search of the Patent Office's pre‑1980 assignment libers (or the "Digest of Assignments" volumes for the 1870s) held by the National Archives, not a query of Assignment Center. I have not performed that archival search.

Because there is no recorded transfer to analyze, the section below is limited to the patent's own lifecycle and carries no assignment content. I am continuing with the remaining required sections, since the signal calls and verdict remain meaningful (they are largely negative findings, which are themselves the answer).

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Timeline diagram

timeline
    title Ownership of US 133556
    1872 : Filed by James L Anderson of Bucyrus Ohio
         : Patent issued to Anderson as sole owner
         : No assignee named at issuance
    1889 : Patent term expires by law
    1980 : USPTO electronic assignment records begin
    2026 : No recorded assignments found for this patent

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NPE / troll-pattern signals

Every signal is assessed against the record above. A "not present" call here is weak evidence of absence in the modern sense — it is primarily a statement that no record exists on which to base the call. I have said so explicitly rather than scoring silence as innocence.

Separate observation, not a signal under your rubric: the Google Patents "Similar Documents" list surfaces a cluster of contemporaneous switch‑lock and switch‑stand patents — US 132,597 (Oct. 29, 1872, "Improvement in switch‑locking devices"), US 123,482 (Feb. 6, 1872), US 113,112 (Mar. 28, 1871, "Improvement in railway‑switch locks"), US 98472 (Jan. 4, 1870), US 130,487 (Aug. 13, 1872). This is dense, fast‑moving prior art in the very months around Anderson's filing, which matters for validity analysis of the 1872 claims — not for ownership. It is outside this brief but worth knowing if the file is ever revisited for patentability rather than title.

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Verdict

Insufficient data.

The record discloses no recorded assignments of US Patent 133,556 — not a single reel/frame, at any date, with any assignor, assignee, or correspondent. The patent issued on 1872‑12‑03 to James L. Anderson of Bucyrus, Crawford County, Ohio, as sole owner, with no assignee designation on its face; Google Patents' legal events show only issuance and the statutory expiration on 1889‑12‑03, with no reassignment events. Critically, the USPTO Assignment Center's coverage begins with assignments recorded since August 1980, so its silence about a patent that expired in 1889 is a database‑scope artifact rather than a finding of continuous individual ownership — the only definitive answer would come from a manual search of pre‑1980 paper assignment libers at the National Archives, which I have not performed. With no chain of title to evaluate, no signal under your rubric can be scored "present," and no NPE classification is supportable in either direction.

Verify directly:

• USPTO Assignment Center — https://assignmentcenter.uspto.gov/
• Assignments on the Web (legacy interface, same underlying records) — https://assignment.uspto.gov/patent/index.html
• Google Patents legal events for this patent — https://patents.google.com/patent/[US133556](/patent/US133556)/en

I'll run targeted searches on the literal identifier, then examine the citation record for US 133,556.

The initial searches returned only false positives on the bare numerals. Let me verify the citation record directly and check the individual "Similar Documents" references.

The searches keep returning unrelated 19th-century switch art. Let me pin down the individual "Similar Documents" references and check for any "Cited By" record.

Prior-Art Report — US Patent 133,556

Target: US 133,556, "Improvement in Railroad-Switch Locks," James L. Anderson, Bucyrus, Ohio. Granted December 3, 1872.
Source of record: https://patents.google.com/patent/[US133556](/patent/US133556)/en (Google Patents mirror of the printed specification; this is the authoritative text supplied in the case file).

Bottom line up front: US 133,556 has no "References Cited" record — examiner or otherwise — because in 1872 the USPTO did not print cited references on the face of issued patents. The only citation-like table available is an algorithmic "Similar Documents" list, which is not a citation record. Below I analyze every entry in that list anyway, gate each against the § 102 date requirement, and map each to the two claims — and I say plainly where I could not verify a disclosure.

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1. What the USPTO/Google Patents record actually contains

Three points of discipline before the analysis:

1. "Similar Documents" ≠ prior art citations. Google Patents generates that list by comparing classification, title, and text similarity across its corpus. It is not a § 102 record, it contains no relevance explanations, and — as shown below — it is polluted by documents issued decades after 133,556, which by definition cannot be § 102 references against it.

2. The absence of a citation list is a function of era, not of search failure. Printed US patents of 1872 carried no "References Cited" section. The USPTO's practice of printing cited references on the face of the patent is a 20th-century development (commonly dated to the late 1940s); I state that with moderate confidence and flag that I did not verify the specific commencement date in an authoritative USPTO source. The practical consequence is that for this patent, no examiner-citation record exists to retrieve, and any tool reporting otherwise would be conflating a similar numeral.

3. § 102 itself is a retrospective frame here. 35 U.S.C. § 102 did not exist in 1872. The operative novelty provision was § 24 of the Patent Act of July 8, 1870 (R.S. § 4886), which barred a patent where the invention was known or used by others before the inventor's invention, or patented or described in a printed publication before the invention or more than a defined period before the application. I apply § 102 below as an analytic lens only, at your instruction, and flag that the statutory text, the critical date rules, and the claim-construction conventions all differ from modern practice.

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2. The controlling problem: the critical date is unknown

US 133,556's filing date is not stated anywhere in the retrieved record (the front matter shows only the 1872-12-03 prior-art/publication date). A § 102 analysis needs a critical date; I do not have one.

I therefore use 1872-12-03 (the issue date) as a deliberately conservative anchor — conservative in the direction of including more references as date-qualified than would actually qualify. If Anderson's true filing date was earlier (which is likely, given 1870s pendency periods), the gate below would exclude still more references. Every date verdict in § 3 is therefore conditional on that anchor.

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3. Reference-by-reference analysis — the source's full "Similar Documents" list

Filing dates: the printed US patents of this era typically do not state an application filing date, and none was stated in the retrieved record for any entry below. I mark these "not stated in retrieved source" rather than inferring them. Descriptions are derived from the titles as listed by the source unless otherwise noted; I flag explicitly where I did not retrieve the specification.

3a. Date-qualified candidates (published on or before 1872-12-03)

3b. Categorically excluded — published after 1872-12-03

These cannot be § 102 prior art against 133,556 under any critical-date scenario, because they postdate the patent's own grant:

US 157,375 (1874-12-01) · US 196,284 (1877-10-23) · US 264,417 (1882-09-12) · US 289,633 (1883-12-04) · US 457,999 (1891-08-18) · US 537,807 (1895-04-16) · US 593,624 (1897-11-16) · US 608,832 (1898-08-09) · US 663,906 (1900-12-18) · US 682,265 (1901-09-10) · US 735,318 (1903-08-04) · US 765,517 (1904-07-19) · US 789,163 (1905-05-09) · US 799,558 (1905-09-12) · US 1,176,664 (1916-03-21)

Fifteen of the twenty-four "Similar Documents" entries are legally incapable of being prior art against this patent. Their presence in the list is itself proof that the list is a similarity ranking, not a citation record. (They are useful in one narrow way only: as evidence of the post-1872 state of the switch-lock art, which is § 103-style context and has no bearing on an 1872 patent.)

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4. § 102 element mapping against the claims of 133,556

Recall the two claims (plain language from the case file):

• Claim 1 — the transverse bolt D, fitted through the vertical slot of lever A, to lock in the notched arcs (recited as "G G" in the claim; "O O"/"C C" in the description — conflict flagged, unresolved).
• Claim 2 — the combination of lever A and bolt D with the ear c and the drop-bolt b, all operating as specified.

For anticipation, a single reference must disclose every element, arranged as claimed. Element-by-element:

Anticipation verdicts:

• US 132,597 (1872-10-29) — Date-qualified; disclosure unverified. The strongest candidate on the calendar, but I cannot say it anticipates claim 1 or claim 2 without its specification. Do not treat this as an established § 102 reference. It is a lead requiring retrieval.
• US 113,112 (1871-03-28) — Date-qualified; disclosure unverified. Nearest in title ("railway-switch locks" vs. 133,556's "railroad-switch locks"). But 1870s "switch lock" art covers both lever locks and point-rail locks, and identity of title is not identity of disclosure. Unresolved.
• US 130,487, US 124,118, US 123,482, US 98,472, US 66,443, US 63,663, US 8,557 — Date-qualified; no verified overlap with either claim. Nothing in these titles reaches a slotted-lever bolt or a keyed drop-bolt/ear combination.
• US 6,394 (1849) — Date-qualified; topically distant. Rail-fastening, per title.
• All fifteen post-1872 entries — Not prior art. Full stop.

Structural observation I can state with confidence: claim 1 is a subcombination claim (bolt + slotted lever + notched arcs), and claim 2 is a combination claim adding the ear and keyed drop-bolt. Claim 1 is the broader claim and therefore the easier one to anticipate; claim 2's ear-plus-keyed-drop-bolt subassembly is the narrower and more defensible element, and I found no reference at all — cited or otherwise — that discloses it.

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5. Candidates discovered in my own search that are not in the source's list

Because the source's list is not a citation record, I also ran independent queries. Two date-qualified documents surfaced that are substantively closer to claim 1's lever-and-notch concept than most of the "Similar Documents" list. I flag these as my search finds, not citations of record, and not verified as anticipatory:

• US 122,319 — James M. Hickman (Richmond, Ind.) & Henry Staufer (Cincinnati, Ohio), "Improvement in Operating Railway Switches," patented January 2, 1872. Discloses a switch-stand whose top has "a slotted semicircular frame, in which is inserted a horizontal arm or lever, L… secured rigidly to the shaft J," with a hinged lever and hook/pin. That is a lever/hinged-arm engagement with a notched arc — conceptually the same family as claim 1. But it shows the operating lever itself engaging the arc slots, not a separate transverse bolt D riding in a vertical slot a in the lever. On that reading it would not anticipate claim 1, and it says nothing about claim 2. Source: https://patentimages.storage.googleapis.com/1a/ec/71/3c37f2fae36c60/[US122319](/patent/US122319).pdf
• US 114,622 — Hiram Strait (Cincinnati, Ohio), "Improvement in Railway-Switches," patented May 9, 1871. Describes a lever N that "will rise and fall a few inches, so as to fasten in a guard, P… with two lever recesses in its top," usable "as a hand lock switch." Again a lever-drops-into-a-notch lock, but with the lever itself engaging stationary recesses rather than a bolt sliding in a lever slot. Not an anticipation of claim 1 as claimed; silent on claim 2. Source: https://patentimages.storage.googleapis.com/e9/00/9b/e29c1516171719/[US114622](/patent/US114622).pdf

These two are worth pulling in full if you need to test claim 1's scope. I could not complete verification of their full disclosures within this run.

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6. What a defensible 1872-era prior-art search would require

Nothing in the modern databases substitutes for this:

1. The printed annual volumes — Report of the Commissioner of Patents (Patent Office, 1849–1872) and its classified digests. The 1872 issue of 133,556 would fall in the Commissioner's Report for 1872.
2. Manual class/subclass search in the original examiner classes for switch-stands, switch-locks, and lever-locks — the retro-classification B61L 5/00 and 5/02 shown on the record is a modern assignment and was not the 1872 classification; searching only by B61L will miss the era's actual classification scheme.
3. Filing dates via the Patent Office's application records (National Archives, RG 241), since the printed documents omit them — this is the only way to fix the § 102 critical date and thus to know whether US 132,597 (granted 35 days before 133,556) is even chronologically capable of anticipating.
4. Contemporaneous non-patent literature — e.g., Scientific American and railroad-trade periodicals of 1865–1872 — which under R.S. § 4886 counted as printed publications.

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7. Explicit uncertainty statements

• I identified zero § 102 references for US 133,556 that I can substantiate. I did not retrieve the specification for any date-qualified reference in § 3a. Every "which claim does it anticipate" answer above is "unverified," not "no." This is an evidence limitation, not a finding of novelty.
• The § 102 date gate in § 3b is the only conclusion in this report I would defend as complete — fifteen listed documents postdate the patent and cannot be prior art to it.
• No filing date exists in the record, so no true critical date can be stated.
• US 130,487 appears in the "Similar Documents" list, but my search for it returned unrelated material — specifically US application serial No. 07/001,304 (the internal application number of US 4,764,430, a 1988 crosslinkable-coatings patent) coincidentally matching the numeral "130487." That is a false positive and is not US 130,487. Reported for identifier discipline; not counted as a reference.
• Arc identifier conflict carried forward: claim 1 recites notched arcs "G G"; the description uses "O O" and "C C." Unresolved, and not auto-corrected.
• Inventor name conflict carried forward: "JAMES L. ANDERSON" in the specification body vs. "JAMES LEWIS ANDERSON" in the signature. Unresolved.
• Historical-practice claim flagged: my statement that the USPTO did not print cited references on patents until the 20th century (commonly cited as the late 1940s) is offered at moderate confidence and was not verified in an authoritative USPTO source during this run.
• Date discrepancy noted: your task header states "Current Date: April 26, 2026"; the session metadata states 2026-09-27. I did not reconcile them and it does not affect any conclusion here.

No contradiction with the previously generated sections was found — the search results this round neither confirm nor disturb the earlier findings on the absent abstract, the 1889 expiration, the two claims, or the identifier conflicts.

I'll build on the prior-art table already established (the Google Patents "Similar Documents" list) and pull the substance of those references so the § 103 analysis is grounded in what they actually disclose.

The first pass surfaced mostly adjacent material rather than the five "Similar Documents" themselves. Let me target those identifiers directly.

Obviousness Analysis — U.S. Patent No. 133,556 (Anderson, "Improvement in Railroad-Switch Locks")

Builds on the previously generated bibliographic, structural, claim, prior-art, and litigation sections; those are not repeated here.

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0. Threshold flags before the analysis

Four items must be stated up front, because they bound everything that follows.

(a) Date contradiction between governing instructions. The current task states "Current Date: April 26, 2026," while the system header states 2026-09-27 and the previously generated section states the Google Patents page was fetched 2026-09-26. This does not affect the § 103 analysis (the patent expired 1889), but I am flagging it rather than silently harmonizing it.

(b) The "Prior Art section" of this page is a Similar Documents table, not a record of citations. As the earlier section correctly noted, the five documents listed (US 132,597; US 113,112; US 130,487; US 98,472; US 6,394) are machine-generated "similar document" neighbors. They are not confirmed examiner citations, and they are not an applicant's statement of the art. Likewise the page's "Prior art keywords" field — lever, bolt, railroad, switch, improvement — is automated keyword extraction from this patent's own text, not a prior-art statement. Do not treat that keyword row as an admission.

(c) Verification status of the five listed documents — I could not retrieve full specifications. I attempted targeted retrieval of US 132,597, US 113,112, US 98,472, and US 130,487 and did not obtain their specification texts within the search budget. Only their numbers, titles, and dates (as given in the table reproduced in the earlier section) are verified. Accordingly, the § 103 mappings below that depend on those references are explicitly conditional on the disclosures being what their titles and dates imply. Where I use a reference whose text I did retrieve, I say so and quote it.

(d) The critical date. The earlier section flagged that no filing date is of record — only the December 3, 1872 grant. For § 103 purposes the critical date is the date of invention, which is unknown. I therefore use December 3, 1872 as the outer boundary, which is the most favorable assumption for the patent: anything published on or after that date is excluded from the prior art. Under that boundary, all five listed documents qualify (1870-01-04 through 1872-10-29). Under that same boundary, several references that surfaced in searching and that look superficially relevant do not qualify as prior art and I exclude them: US 152,616 (1874), US 154,439 (1874), US 162,460 (granted 1875), US 218,110 (1879), US 273,450 (1883), US 357,109 (1887). Flagging this prevents the common error of citing later, better-drafted switches against this patent.

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1. Governing legal standard

35 U.S.C. § 103 did not exist in 1872. It was enacted by the Patent Act of 1952. Any § 103 analysis of this patent is therefore retrospective and hypothetical. Two frames are available and, importantly, they converge:

The 1872 frame was, if anything, harsher on this patent. The era's "double use" and "analogous use" doctrines held that transferring a known device to an analogous purpose, or mere change of location, was not invention. If a gravity detent bolt engaging a notch was already known for holding a movable member in a set position, moving it to a switch-lever quadrant is a textbook double use under 1870s law and equally obvious under KSR.

Two further doctrines matter for claim 2:

• Aggregation: where elements in a combination claim perform no coaction and produce only the sum of their separate results, the claim is void as an aggregation. Lincoln Eng'g Co. v. Stewart-Warner Corp., 303 U.S. 545, 549–52 (1938).
• Combination claims and old elements: a combination of individually old elements is not automatically anticipated — Aro Mfg. Co. v. Convertible Top Replacement Co., 365 U.S. 336, 344–45 (1961) — but the elements being old remains highly probative of § 103 obviousness.

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2. Person having ordinary skill in the art (PHOSITA), as of late 1872

A railroad machinist / switch-stand maker with several years' experience, familiar with:

• the standard switch stand: a lever rotating in a quadrant, semicircular, or slotted segment frame, with some means of holding the lever at the "normal" and "reverse" positions;
• gravity and spring detents — pins, stops, and bolts dropping or being sprung into notches and recesses to hold a sliding or swinging member;
• locks: keyed boxes and padlock staples applied to switch levers, their purpose being to prevent unauthorized or inadvertent throwing of the switch.

This is not a speculative level of skill. I retrieved contemporaneous text confirming each component:

• Lever in an arc-shaped frame with defined seating positions: US 122,319 (Hickman & Staufer, granted Jan. 2, 1872 — eleven months before 133,556) recites "the top of the switch-stand is provided with a slotted semicircular frame, in which is inserted a horizontal arm or lever, L, which is secured rigidly to the shaft J and serves to operate the same." That is a switch lever operating in a notched/slotted arc. (https://patentimages.storage.googleapis.com/1a/ec/71/3c37f2fae36c60/[US122319](/patent/US122319).pdf)
• Lever seated into one of two recesses in a fixed guard: US 114,622 (Strait, May 9, 1871) — a lever whose "outward end will rise and fall a few inches, so as to fasten in a guard just outside of the track, with two lever-recesses in its top, one for a full right and the other for a full left hand switch," described as a "hand lock switch," with "a spring … to hold the lever securely in its place." (https://patentimages.storage.googleapis.com/e9/00/9b/e29c1516171719/[US114622](/patent/US114622).pdf)
• Spring-pressed stop dropping into one of two recesses to lock a switch member, with guards against accidental movement: US 87,529 (Wharton, Mar. 2, 1869) — "There are two recesses, d e, … in which the stop, J, fits … The stop, J, is forced into the recesses by the spring, N"; and "The guards prevent the slide from being moved accidentally." (https://patentimages.storage.googleapis.com/2a/5d/83/fe816d66f72338/US87529.pdf)

I emphasize: these three are not in the page's Similar Documents list. I use them only as evidence of what a PHOSITA knew, which KSR permits. Where a rejection would rest on them as references, an examiner would have the burden of establishing them as prior art and of avoiding conclusory "common knowledge" assertions. K/S HIMPP v. Hear-Wear Techs., 751 F.3d 1362, 1366–67 (Fed. Cir. 2014).

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3. Claim scope, and the single most important observation in this analysis

Restating the two claims only as needed for the mapping (they were reproduced in full in the earlier section):

• Claim 1: "The transverse bolt D, fitted through the vertical slot of the lever A to lock in the notched arcs G G, as set forth." Claim 1 does not recite gravity, does not recite that the arcs are stationary or connected to frame B, and does not recite a key or lock.
• Claim 2: "The combination of the lever A and bolt D with the ear c and drop-bolt b, all operating as specified."

The observation: the specification describes — and the invention statement emphasizes — "an ordinary key for raising the drop-bolt and liberating the lever when desired," plus a keyhole in the box E. Neither the key, nor the keyhole, nor the box E, nor the locked/tamper-resistant character of the assembly appears in either claim. Claim 2 stops at the ear and the drop-bolt. The only feature that distinguishes the commercial point of the invention from a plain positional detent — that it is key-secured against unauthorized operation — is described but not claimed, and therefore cannot supply patentability to either claim.

This is not a § 112 objection; it is a claim-scope fact that materially widens obviousness exposure, because the art need only supply an ear-and-drop-bolt, not a keyed lock.

A second scope note carried forward: claim 1 recites "notched arcs G G" while the description uses arcs "O O" and "C C." Per the strict-identifier rule I do not reconcile these. The analysis assumes, but does not assert as verified, that "G G" and "O O"/"C C" denote the same pair of arcs in the drawing.

Third scope note: the two claims are not in dependent form — claim 2 does not incorporate claim 1. So claim 2 must independently contain every element of the combination it recites. It does recite bolt D, so the claim-1 bolt is carried in, but the arcs are not recited in claim 2.

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4. Claim 1 — combinations rendering the claim obvious

Claim 1 is the broad, thin claim: an element (bolt) mounted for reciprocation (through a slot) in a moving member (the lever) and engaging (dropping into) complementary features (notches) on a fixed member (the arcs). Two combinations and one single-reference theory are available.

Combination I-A — Switch-stand lever-in-notched-quadrant + detent bolt in a slot

Motivation to combine. Three independent rationales, any one sufficient under KSR:

1. Same field, same problem. All references are switch-operating mechanisms whose express object is to hold the switch in a thrown position. There is no field-boundary problem; this is not an analogous-art question at all. In re Bigio, 381 F.3d 1320, 1325–26 (Fed. Cir. 2004).
2. The notches are pre-existing structure, and their function is the asserted function. Where the primary reference already provides an arc with position features for a lever, using those features as the seat for a detent is the use for which they exist.
3. A slot as the mounting for a captive bolt is the known mechanical expedient. One of ordinary skill does not need teaching to be told that a bolt that must travel with a swinging lever and reciprocate with respect to it is carried in a slot in that lever.

Expectation of success: high and predictable. A bolt seated in a notch blocks the arc-relative motion of the lever by direct interference. Nothing in the combination is unpredictable.

Combination I-B — The two switch-lock references read together

US 113,112, "Improvement in railway-switch locks" (1871-03-28), and US 132,597, "Improvement in switch-locking devices" (1872-10-29) are, by title, both directed to locking a switch member, and both pre-date the grant. A combination of US 132,597 (primary, a switch-locking device) with US 113,112 (secondary, a railway-switch lock) is the most natural pairing an examiner would draw from this page's own neighbor table.

Critical caveat: because I could not retrieve either specification, I cannot state what either discloses, cannot state which element each supplies, and cannot state that either discloses a bolt through a slot engaging notched arcs. The conditional shape of this combination is: if the primary discloses a lever-locking bolt and the secondary a notched arc or equivalent, the combination is obvious for the reasons in I-A. I am flagging this as an unverified theory, not a conclusion. An examiner proposing this combination would bear the burden of showing the disclosures, and this analysis should not be cited as if that showing had been made.

Single-reference theory against claim 1

If US 130,487 or US 98,472 discloses a switch-stand lever whose locking position is defined by notches in a fixed segment, and a bolt movable in the lever to enter them, claim 1 is anticipated rather than obvious — and if the only difference is the recitation of a "slot," that is at most an obvious mounting detail. I cannot verify this from the retrieved material, and I decline to assert it.

Why claim 1 is highly vulnerable

Claim 1 is drafted with no structural context beyond the lever, the slot, the bolt, and the arcs. It omits the frame B, the rigidity of the arcs, gravity actuation, and the entire lock. Read in light of the specification under 1872 practice, it is a claim to the position-detent alone, and positional detents for switch levers were, on the retrieved contemporaneous evidence, old (Strait 1871: two lever-recesses in a guard with a spring holding the lever; Wharton 1869: stop J into recesses d, e). Claim 1 is, in my assessment, more likely than not invalid under § 103 on the combination of the art in the PHOSITA's possession as of 1872 — subject to the verification gaps in § 0(c).

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5. Claim 2 — combinations rendering the claim obvious

Claim 2 adds the projecting ear c on lever A and a drop-bolt b that drops into a notch of the ear. Functionally, an ear on the moving lever entering a fixed receptacle and being engaged by a downward-moving bolt is the universal lock-bolt/keeper construction.

Combination II-A — Claim 1 combination + a keyed switch-lever lock

Motivation to combine. The patents' own stated object controls: the specification says the invention is "for locking the switch-levers on railroads automatically and effectively," and the second aspect is a key-secured lock. The motivation is therefore expressly supplied by the applicant's own problem statement — the strongest form of motivation, because it is not imputed to the PHOSITA but stated by the inventor. An artisan seeking an effective, key-secured hold on a switch lever, aware of existing keyed switch locks (US 113,112; US 132,597), would combine that lock with the detent of claim 1 as a matter of ordinary design.

19th-century authority directly on the skill level. Brahn v. Ramapo Iron-Works, 35 F. 63, 64 (C.C.S.D.N.Y. 1888), addressing a switch-stand locking claim, held that substituting "a single padlock staple rotating with the shaft, for the three exactly similar but fixed padlock staples of the Lukens patent" would "show no substantial invention above ordinary mechanical skill, and be void." That is precisely the character of the step from the claim-1 detent to the claim-2 ear-plus-drop-bolt: the substitution of one known locking engagement for another on the same lever.

The aggregation problem, and its honest counterargument

Against claim 2: bolt D and bolt b each independently block the same lever from the same motion. Neither enables the other; each is a complete lock by itself. On that reading, claim 2 recites a mere aggregation of two redundant locks producing only the sum of their separate results — the classic invalidity. Lincoln Engineering, 303 U.S. at 549–52.

For claim 2: the claim says "all operating as specified," and the elements do coact in a physical sense — bolt b acts upon the ear c, which is a part of lever A, so the drop-bolt exerts its locking force through a claimed element of the combination, not independently of it. Redundancy is not the same as non-coaction. This is a genuinely arguable point and, in my view, claim 2 is meaningfully more defensible than claim 1 — though the defense is narrowness (a specific combination) rather than a showing of unexpected result.

A fourth possibility: claim 2 fails for a scope reason, not an art reason

Because the key and keyhole are not claimed (see § 3), any prior-art ear-and-drop-bolt lever lock — whether key-operated, handle-operated, or otherwise — practices claim 2 as written. Claim 2 therefore gives up the very narrowing that would distinguish it over a simple latch. If the art contains any lever lock with a lug entering a bolt housing, claim 2 falls under either § 102 or § 103.

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6. Consolidated motivation-to-combine record

For the record required by KSR, the specific rationales available here are:

1. Express problem statement in the patent itself (specification: automatic and effective locking of switch levers; keyed release). This alone satisfies the motivation requirement for claim 2's added elements.
2. Same field of endeavor and same problem across all candidate references — switch stands and switch locks. No analogous-art barrier, no field-of-invention dispute.
3. Predictable, mechanical result. Bolt-into-notch is direct interference locking; force is resisted structurally, not by friction or chemistry. No unpredictability to argue.
4. Design incentive / improvement of a known mechanism. Every switch stand in the art already has some means of holding the lever; improving the hold is the ordinary reason to modify a switch stand.
5. Known technique, known solution to a known problem. Slot-mounted captive bolt, spring/gravity detent into recess, and padlock/lock-box on a lever were each independently established.
6. "Obvious to try" is available but is not needed and I do not rely on it.

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7. Verification table — what I actually confirmed

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8. What would defeat this analysis (counterarguments to preserve)

• Verified disclosures of the five listed documents. My I-A and I-B mappings for those references are conditional. If US 130,487 or US 98,472 turns out to be directed to rail fastening or to a non-lever mechanism (as US 6,394's title suggests for that document), the primary reference for I-A disappears and must be replaced.
• An earlier invention date. If the filing date (not of record) is well before December 3, 1872, some candidates could drop out. My use of the grant date is deliberately pro-patent.
• Narrow construction under 1872 practice. Courts of the era read claims narrowly against a crowded art where validity was at stake — see Vermilya v. Pennsylvania Steel Co., 87 F. 481, 482 (C.C.E.D. Pa. 1898) ("the claim … cannot be broadly construed, but must, in view of the prior art, be restricted to the particular devices substantially as described"), and Johnson v. Forty-Second Street, M. & St. N. Ave. R.R., 33 F. 499, 501–02 (C.C.S.D.N.Y. 1888) (combination of old elements sustained where the assemblage was new and practically successful). Conversely, Brahn, 35 F. 63, and the Johnson court's own observation that "the separate elements of the combination were old" cut the other way. The outcomes in this art were fact-specific and split; a § 103 conclusion here is a probability judgment, not a certainty.
• Narrow reading of claim 1. If "fitted through the vertical slot of the lever A" is construed to require the specific slot-and-bolt relationship shown, the claim is narrower and the art must supply that relationship, not merely a detent. I do not think this saves claim 1, but it is the best available construction argument.
• Secondary considerations. I found no evidence of unexpected results, no licensing or commercial-success record, and no nexus evidence in the material retrieved. The earlier sections found no assignment record and no litigation, which also removes any source of presumed-validity or industry-acclaim evidence. Absence of secondary considerations is not a finding against the patent, but there is nothing here to weigh in its favor.

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9. Bottom line and confidence

• Claim 1 — more likely than not obvious under § 103 on the combination of a switch-stand lever operating in a notched quadrant/segment (US 130,487 and/or US 98,472, as listed) with a gravity- or spring-detent bolt and the slot-mounting expedient, corroborated by verified contemporaneous art (US 122,319; US 114,622; US 87,529). Confidence: moderate, because the primary references' texts are unverified.
• Claim 2 — likely obvious under § 103 as the claim-1 combination plus the standard ear/lug-and-drop-bolt keeper arrangement, with the motivation supplied by the patent's own statement of purpose; and independently vulnerable because the keyed-lock feature that gives the combination its only real novelty is not claimed. Confidence: moderate. The aggregation counterargument (each bolt locks independently) and the narrow-construction argument are the patent's best defenses.
• Faithful caveats: (i) the five "Similar Documents" are not examiner citations and I could not verify four of their disclosures; (ii) § 103 did not exist in 1872, and the contemporaneous "invention" standard, supplemented by the era's double-use doctrine, would if anything have been harsher; (iii) I have not verified the grant against USPTO PatentCenter or the Official Gazette, and the specification text is taken from https://patents.google.com/patent/[US133556](/patent/US133556)/en as set out in the earlier section.