US 281415

I'll run targeted searches for this exact patent number before summarizing.

Search results note

I could not query USPTO PatentCenter, the USPTO assignment database, or PACER/CAFC dockets directly with the tools available to me — I ran open web searches instead. I also note a date discrepancy: your prompt says April 26, 2026, while my session context says 2026‑09‑24. Nothing in the findings below turns on that.

US 281,415 — summary

Title caveat (do not auto-correct): Google Patents displays the title field for this record as "Eoy stone", which is an OCR corruption of "Roy Stone." The authoritative printed title on the specification is "HYDRAULIC EXCAVATING‑MACHINE." The document text is likewise OCR‑damaged elsewhere ("HYDRAULIC EXGAVATING MAGHINE," "ROY STONE, OF NEWV YORK, N.").

Corroboration: The Annual Report of the Commissioner of Patents for 1883 indexes "Stone, Roy, New York, N. Y. — Hydraulic excavating‑machine. 281,415, July 17" (HathiTrust, seq. 325). The same index entry shows Stone's related No. 271,538 ("Grapple," Jan. 30, 1883). Stone is also the named patentee on later U.S. patents, e.g. No. 788,611 (Overhead Shield for Tunneling, 1905).

CAFC / 2026 docket check — negative result

No CAFC or 2026 litigation docket exists for this patent. Two independent reasons:

1. US 281,415 expired in 1900, and the Court of Appeals for the Federal Circuit did not exist until 1982 (Federal Courts Improvement Act of 1982). There is no appealable controversy to docket.
2. Searches for "281415" combined with 2026 Federal Circuit terms returned only unrelated hits: an EU TED procurement notice 281415‑2026 (German joinery contract, Stadt Norderstedt) and a Panamanian trademark register entry REGISTRO: 281415 (SG Gaming, Inc., mark "KASCADA"). Neither involves this patent. Federal Circuit 2026 case summaries (Gibson Dunn June 2026 update; Oblon September 2026 newsletter) contain no reference to Stone or to a 1883 hydraulic excavating patent.

One caveat I want to flag rather than assert: a CourtListener document I retrieved shows later Board of Appeals decisions distinguishing "Stone or Gage" references in suction‑nozzle jet art. I cannot confirm that the "Stone" cited there is US 281,415; it is at least as likely to be one of Stone's later patents or a different patentee. Treat that as unresolved.

Independent claims — plain language

This patent has two claims, both independent (claim 2 does not depend from claim 1). Both are classic 1883‑era combination claims closed with "substantially as set forth," which pulls in the disclosed structure as a functional limitation.

Claim 1 — The combination of: (a) a straight induction tube whose inlet end flares outward; (b) a water‑supply pipe; (c) an inducing jet tube that passes around the lower end of the induction tube and discharges upward inside it to drive the suction current; and (d) a separate boring jet tube that plays on the material in front of the mouth. In substance: take a straight, flared‑mouth suction pipe and fit it with a wraparound upward‑firing eductor jet plus a forward‑firing digging jet, and the combination is the invention.

Claim 2 — The combination of: (a) the water‑supply tube together with one or more induction nozzles and boring nozzles; and (b) an induction tube having a flaring lower end. This is the multi‑nozzle variant (Fig. 2 shows two or more supply pipes with paired nozzle sets acting at opposite parts of the flared mouth), claimed as a combination without the "straight tube" and "passing around the lower end" limitations of claim 1.

What the specification disclaims (negative limitations, not claims but narrowing context): the inventor expressly stated he does not claim (i) an induction tube with a curved or hopper‑shaped end plus a jet tube (power lost forcing material around the curve); (ii) an ejector tube with an annular discharge (long narrow opening causes friction); (iii) an induction tube with a curved shoe larger than the tube and a jet tube inside it (jet strikes the shoe side instead of acting in line with the eduction tube); or (iv) an eduction tube with a flaring end and a swivel‑mounted jet tube moved by handles (liable to be misplaced). The stated advantage is that the jet nozzle is fixed in position so the tube and nozzle behave as one implement.

Stated objects/benefits: generate the required current in the induction tube; keep the nozzle from obstructing material passing up the tube; permit use in shallow water (nozzles can be hooked on the flared rim and positioned below water level); and aim the boring jet at the material to best advantage.

Prior art and forward citations:

• The specification expressly references the inventor's own earlier Letters Patent No. 224,809 (induction tube with upward jet nozzle and a front boring jet) as the starting point.
• Google Patents lists four forward citations: US 2,783,972 (Fur Grundwasserbauten AG, 1957); US 2,879,649 (Hartwell A. Elliott, 1959); US 3,161,438 (Milton J. Novak, 1964); US 3,451,149 (Munsch Research & Dev Corp., 1969). No backward citations are listed.

Uncertainty disclosure

• Assignee/inventor-of-record: High confidence there is no assignee on this patent, based on the grant text and the 1883 Commissioner's index. I did not query the USPTO assignment database directly, so I cannot rule out an unrecorded or separately recorded assignment.
• Whether the "Stone" reference in later Board of Appeals decisions is this patent: Low confidence — unresolved, as noted above.
• CAFC 2026 docket: High confidence the answer is negative; the 1900 expiry and the court's 1982 creation make 2026 appellate activity for this patent impossible, and no search hit contradicts that.

I'll search for litigation involving US Patent 281,415 specifically.

Let me check the litigation-specific databases directly.

Let me try a couple of final targeted queries on litigation databases.

Litigation Search Results: US Patent 281,415

Conclusion: No litigation is known involving US Patent 281,415.

I searched litigation-oriented sources (Unified Patents litigation portal, CourtListener, Docket Alarm, PACER-adjacent aggregators, and general web queries for the patent number paired with "litigation," "infringement," "lawsuit," and "court"). No case — district court, ITC, PTAB, or CAFC — was found in which US 281,415 was asserted, challenged, or otherwise at issue.

Why this result is expected — and why my search is reliable on this point

The patent itself establishes why no litigation exists:

• Title: "Eoy stone" (Google Patents' transcription of the OCR'd title; the specification identifies it as "HYDRAULIC EXCAVATING-MACHINE").
• Patentee: Roy Stone, of New York, N.Y. Application filed October 20, 1882; patent granted July 17, 1883.
• Legal status: Google Patents shows "Expired – Lifetime," with an anticipated expiration date of 1900-07-17. Under the law then in force (pre-1995 term rules), the patent term ran 17 years from grant. The patent has been off the books for roughly 126 years.
• Claims: Only two claims, directed to a combination of a straight induction-tube with a flaring inlet end, a water-supply pipe, an inducing jet-tube passing around the lower end of the induction-tube, and a boring jet tube (claim 1); and a similar combination (claim 2).

A patent that expired in 1900 cannot be asserted in any modern infringement action, and its term predates the existence of the Federal Circuit (1982), the ITC's modern Section 337 practice, and the PTAB (2012). Any enforcement would have had to occur in the 1880s–1890s.

Caveat on historical (19th-century) litigation

I want to be explicit about the limits of what I can verify. Pre-1900 federal circuit court decisions are sparsely digitized — CourtListener and similar free databases have acknowledged gaps in lower federal court opinions before roughly 1925 (one source I retrieved notes CourtListener's "lack of coverage of older federal and state cases" is its "most major" weakness compared to Westlaw/Lexis). It is therefore possible, though I have found no evidence, that Roy Stone enforced this patent against a competitor in the 1880s or 1890s in a circuit court proceeding that never produced a published opinion. I cannot rule that out with certainty, and I will not fabricate a case to fill the gap. Confirming the negative would require a manual Westlaw/Lexis historical-database search or the printed Federal Reporter/Circuit Court volumes for 1883–1900.

Namesake/identifier disambiguation (explicitly screened out)

The searches returned many hits on the string "415" or the number 281415, none of which relate to US 281,415. These are noted here only to show they were checked and excluded:

Bottom line

Presently, on the basis of the searches performed, there is no known litigation involving US Patent 281,415. The patent issued in 1883, expired circa 1900, and was legally unassertable thereafter. Any historical enforcement would predate modern litigation databases; I found no evidence of it, and I flag that pre-1925 federal trial-court coverage is incomplete in the free sources available to me.

Proceedings overview

Total AIA trial proceedings on file for US 281,415: 0. Breakdown by status: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0. The structured "PTAB proceedings on file" block (USPTO Open Data Portal) returns no AIA trial proceedings for this patent as of the most recent ingest, and my targeted web searches surfaced nothing to contradict that default — see "Search diligence" below. The bottom-line defensive posture is therefore not "hardened by PTAB" and not "claims canceled by PTAB"; it is stronger and simpler: this patent has been legally dead since 1900-07-17. Any demand letter citing US 281,415 is asserting an expired 1883 patent, and there is no IPR/PGR/CBM record to analyze because none can exist.

Why there are no proceedings (structural, not a data gap)

• The PTAB did not exist. AIA trials (IPR/PGR/CBM) were created by the Leahy‑Smith America Invents Act in 2011; the PTAB began receiving petitions in 2012-09-16. US 281,415 issued 1883-07-17 and, per the Google Patents record, reached its anticipated expiration 1900-07-17 ("Status: Expired - Lifetime"). A tribunal created 129 years after expiry has no jurisdiction-conferring controversy to decide, and IPR of an expired patent is in any event of marginal practical value (no amendment, no live exclusionary right).
• The Federal Circuit also did not exist. No CAFC appeal is possible either; the court was created in 1982. The only "appellate" artifacts are the 1883-era record itself.
• The record's own history is pre-AIA and intra-family. The specification states the invention is an improvement on the inventor's earlier Letters Patent No. 224,809 ("In Letters Patent No. 224,809, granted to me, there is an induction-tube in which a current is set up by water issuing from a jet-nozzle…"). That earlier Stone patent is a § 102/§ 103 analogue in the modern sense — the patent itself frames 224,809 as the starting art and disclaims several structures (hopper-ended induction tube + jet tube; ejector tube + annular discharge; curved shoe; swivel-mounted jet tube). No live modern patent claims priority to this 1883 filing in the record, and any such priority claim would be facially incredible.

No proceeding entries are listed below because none exist. I will not generate placeholder proceeding numbers. Per the task constraint ("Do not invent proceeding numbers"), fabricating an IPR number here would be the single most damaging error available.

Strategic summary

Claim status. US 281,415 as issued carries two claims, both combination claims: claim 1 — "The combination, with a straight induction-tube with a flaring inlet end, of a water-supply pipe, an inducing jet-tube passing around the lower end of the induction-tube, and a boring jet tube, substantially as set forth"; and claim 2 — "The combination, with the water-supply tube and one or more induction and boring nozzles, of an induction-tube having a flaring lower end, substantially as set forth." Neither claim was ever canceled or sustained by the PTAB, because no PTAB proceeding exists. Both claims nonetheless stand expired as of 1900-07-17 — the operative legal fact. There are no surviving enforceable claims, no untested claims, and no narrowing for IPR purposes. Treat every claim of this patent as EXPIRED, not merely "invalid."

Estoppel landscape. § 315(e)(2) estoppel is a null set: with zero petitioners there are zero estopped parties, and no IPR ground is "reasonably could have raised"-barred against anyone. That cuts against, not for, a defendant — there is nothing to inherit. Conversely, if you are defending modern dredging/suction-head patents, US 281,415 is fully available as prior art: it is an 1883-07-17 publication under AIA § 102(a)(1) and, for pre-AIA patents, an unquestionable § 102(b) reference more than a century before any critical date. Note the art-unit lineage — the ODP/CPC classification assigned to this patent is E02F3/925 ("Passive suction heads with no mechanical cutting means with jets"), which places it squarely in the modern suction-head art, and the record lists four forward-citing US patents (US 2783972, US 2879649, US 3161438, US 3451149; issued 1957–1969), i.e., later artisans treated it as citable prior art. Its disclosure of a jet nozzle curved around from the supply pipe so the water-supply pipe need not be attached to the induction tube, and of a separate boring-jet at the bend/return nozzle, is useful § 103 material against claims to flared-mouth eductor heads.

Pattern signals. No petitioner has filed anything, let alone multiple IPRs; no patent owner appeal activity (impossible pre-1982); no defensive aggregator (Unified Patents, RPX, etc.) in the chain — Unified was founded in 2012 and addresses assertable patents, and this patent was already 112 years expired. The absence of PTAB activity here is not the usual "well-asserted patents eventually attract IPRs" signal. It is a chronological impossibility, and the correct inference is the opposite of a litigation-tested patent: nobody has ever had to defend this patent because it lapsed 26 years before the Wright brothers flew at Kitty Hawk.

Data caveats for the file (flag, don't propagate). The Google Patents title field returns "Eoy stone," which is an OCR corruption of the inventor's name (Roy Stone, of New York, N.Y. — the record also shows "ROY STOL" and "ROY STONE" in the signature/witness block). The true title is "Hydraulic Excavating-Machine," application filed 1882-10-20, granted 1883-07-17. The duplicate entries "US281415D" / "US281415DA" are numbering-artifact duplicates of the same 1883 document, not separate patents. None of these are proceedings.

Search diligence. Queries for IPR/PGR/CBM petitions against US 281,415 or a "Roy Stone" hydraulic excavating machine, and for PTAB materials on the number, returned only unrelated modern hits (a Stone reference in IPR2020-01663 concerning U.S. 9,271,015; a Panamanian trademark registration number 281415 for "KASCADA"; and an unrelated numeric match in a Welsh water-quality dataset). Nothing resembling an AIA trial. I did not locate any Federal Circuit, CourtListener, or PTAB E2E docket for this patent number.

Recommended next steps

1. If you received a demand letter citing US 281,415: the response is a one-paragraph expiration letter, not a PTAB strategy. Quote the ODP record — "Anticipated expiration 1900-07-17," "Status: Expired - Lifetime" — and note that the patent's 17-year term under the then-governing law ran from the 1883-07-17 grant. An expired patent cannot be infringed; there is no live exclusionary right to license. Preserve the letter as evidence of bad-faith assertion.
2. Verify the number before you respond. Confirm the assertion is not a truncated or transcribed modern number. US 281,415 is a six-digit 1883 grant; a demand letter in 2026 almost certainly concerns a differently-numbered patent (e.g., a modern 8-digit number or a foreign registration) that has been garbled. Check the number as served in USPTO Patent Center (https://patentcenter.uspto.gov) and the E2E/ODP record before drafting. If the asserted number truly resolves to the 1883 Stone patent, the assertion is frivolous on its face.
3. If you are the one asserting: there is no FWD to link to and no disposition to quote, because no FWD exists. Do not draft around a phantom proceeding. See the canonical record at https://patents.google.com/patent/[US281415](/patent/US281415)/en and the PTAB's public decision portal at https://e2e.uspto.gov/ if you need to confirm the null result yourself; CourtListener (https://www.courtlistener.com) returns no appellate docket for this patent number.
4. If your real interest is invalidity of a modern dredging patent: use US 281,415 affirmatively. Ground it as (i) an 1883-07-17 printed publication under § 102(a)(1) and (ii) evidence of the state of the art in CPC E02F3/925. Its specific teachings — flared inlet end sized to admit peripheral jet nozzles; jet nozzles curved from the supply pipe to deliver an upward jet within the induction tube; a separate boring-jet at the bend/return nozzle aimed at the bank; nozzles strapped to the tube edge so the assembly "become[s] one implement, to be handled as a whole" — are all quotable from the specification and are the kind of structural detail that defeats a later "novel eductor head geometry" claim.

Bottom line for a defendant today: zero PTAB proceedings, zero § 315(e)(2) estoppel, and zero enforceability. The patent expired 1900-07-17; any infringement theory built on US 281,415 is baseless, and the only current legal utility of this document is as prior art against other people's patents.

I'll research this before writing. Note upfront: US 281,415 issued in 1883, which predates the modern reel/frame assignment recording system (established in the mid-20th century), so I need to verify what, if anything, exists in the Assignment Center.

Strong hit: the inventor is Roy Stone, the Civil War general and first head of the Office of Road Inquiry. Let me pin down two details before writing.

Analyst note on the assignment-record question

Two structural facts must be stated before anything else, because they determine what the Assignment Center can possibly contain:

1. US 281,415 issued 1883-07-17 — 69 years before the USPTO reel/frame recording system existed. The numeric reel/frame indexing convention that the Assignment Center (and its predecessor at assignment.uspto.gov) exposes only reaches back to roughly the mid-20th century. Pre-1950s conveyances were recorded in bound Liber volumes and are generally not retrievable by patent number in the modern database. Any "Reel NNNNNN/NNNN" citation for an 1883 patent would therefore be an artifact and should be treated with suspicion wherever it appears.
2. My available tooling is web search, not a live query against the Assignment Center application. I did not execute an authenticated/JS-driven search of assignmentcenter.uspto.gov. I searched for indexed records and for Google Patents legal events and found none. I am flagging this explicitly rather than implying I ran the query.

The Google Patents page fetched for this patent confirms the negative: its only legal-status entries are "Expired - Lifetime" and "Anticipated expiration" (1900-07-17). There is no "Assignee" field, no assignment event, and the "Family" entry (ID 2350625) shows a single US application with no assignee. (Also note: the page title renders as "Eoy stone" — an OCR corruption of Roy Stone — which degrades keyword searching.)

I am nonetheless delivering the full analysis rather than stopping at the timeline section, because your verdict taxonomy explicitly provides for the no-records case ("Insufficient data — no records, or only the original assignment"), and because the NPE question here is independently answerable from historical sources. No assignment has been invented below.

Inventors

Roy Stone, sole inventor. Residence on the patent: New York, N.Y. (later specifications in his portfolio give the borough of Manhattan, city, county, and State of New York). Application filed 1882-10-20; patent granted 1883-07-17.

• Employer at time of filing: none corporate — he was an independent civil engineer and marine-excavation inventor working on his own account. This is determinable with reasonable confidence and matters for the chain: at filing Stone was not a federal employee and not an employee-inventor of any company. His federal service came later — he headed the Office of Road Inquiry (the predecessor of the Federal Highway Administration) beginning in 1893 (FHWA history; Wikipedia). ⚠️ Source conflict: the Wikipedia infobox separately gives a Division of Public Roads tenure of "October 3, 1883 – October 13, 1899," which is inconsistent with the 1893 statutory creation of the ORI. The conflict is unresolved on the sources I retrieved, but it does not affect the filing-era conclusion, since both dates postdate the 1882 filing.
• Unusual pattern — the inverse of the "inventor departs original assignee" tell. There was no original assignee to depart from. The notable behavioral pattern is different: Stone freely licensed and then publicly dedicated his work. The U.S. Army Corps of Engineers recorded that Stone permitted the government to use his hydraulic excavator (cited in the source as Patent No. 224,309) "without charges for royalty" (Western Pennsylvania Historical Magazine, vol. 50 no. 1 (1967)); and in 1903 the New York Times reported, regarding his steel-wagon-way patents, that "his interest in such patent or patents is dedicated to the public, and that he expects no further advantage from the use of the system" (NYT, 1903-02-01). This is the opposite of an assertion posture.
• Portfolio context (same inventor, same field): US 271,538 (Grapple, granted 1883-01-30) and US 281,415 (Hydraulic excavating-machine, granted 1883-07-17) are listed consecutively under "Stone, Roy, New York, N. Y." in the Annual Report of the Commissioner of Patents for 1883 (HathiTrust). Stone continued to patent in this space at the end of his life: US 788,611, Overhead Shield for Tunnelling, filed 1903, granted 1905-05-02 (PDF). He died 1905-08-05.
• ⚠️ Unresolved OCR ambiguity in the specification I was given: the patent text states "In Letters Patent No. 224,809, granted to me…" while the Corps of Engineers passage is indexed as 224,309. At least one is an OCR error. I am not resolving it by assertion.
• The only named individuals besides Stone in the available text are signature witnesses GEO. T. PINCKNEY and WILLIAM G. MOTT. No solicitor or attorney of record is legible in the OCR.

Original assignee

None. The patent issued to Roy Stone as an individual, with no assignee named on its face, and no attorney/solicitor line legible. This is corroborated independently by the 1883 Commissioner's report, which annotates assignees where they exist — e.g., in the very same alphabetical listing, "Stone, Thomas, et al. (See Dunn, William J., assignor.)" — but lists Stone, Roy with no assignor/assignee annotation for either 271,538 or 281,415.

• Products / reduction to practice: No commercial product line. The subject matter was, however, genuinely reduced to practice and deployed — Stone's hydraulic excavator was used on Diamond Reef, New York Harbor, in 1878 under Army Corps of Engineers harbor work, where it was reported to be "removing the reef more rapidly and more economically than anyone had expected." His primary line of business was civil engineering and marine/harbor excavation, later federal road administration.
• Current status: dissolved by operation of law and mortality. The patent term expired 1900-07-17 (Google Patents "Anticipated expiration"), the inventor died 1905-08-05, and the asset has now been in the public domain for roughly 126 years. There is no successor entity holding it.
• The four later patents citing US 281,415 as prior art (1954–1969: Fur Grundwasserbauten AG; Hartwell A. Elliott; Milton J. Novak; Munsch Research & Dev Corp) are citations, not assignees — no ownership relationship exists.

Assignment timeline

The USPTO Assignment Center has no recorded post-issuance assignments for US 281,415. I state that plainly, and I am not fabricating reel/frame entries. The chronology below is the ownership-relevant chronology of the patent itself, sourced from the patent document, the 1883 Commissioner's report, and Google Patents legal events — not from assignment records.

• 1882-10-20 — Application filed by Roy Stone, New York, N.Y. (Serial and examiner data not legible in the OCR.) Conveyance: none. No assignee executed or recorded at filing.
• 1883-07-17 — US 281,415 granted to Roy Stone, individually. No assignment on record; the 1883 patentee listing carries no assignee annotation. (Compare the adjacent "Stone, Thomas, et al. (See Dunn, William J., assignor.)" entry, which shows the report did flag assignees when present.)
• 1900-07-17 — Anticipated expiration / "Expired - Lifetime" per Google Patents legal events. Rights-terminating event, not a conveyance.
• n/a — No assignment, security agreement, merger, change of name, license, release, or correction recorded at any point. No correspondent of record exists for this patent because no recording was ever filed.

Timeline diagram

Rendered as the patent's actual ownership chronology, since there are no assignment events to chain.

timeline
    title Ownership of US 281415
    1882 : Filed by Roy Stone of New York
    1883 : Patent issued to Roy Stone
         : No assignee named on its face
    1900 : Patent term expires
    1905 : Inventor Roy Stone dies

NPE / troll-pattern signals

Applied to a patent with a terminated term and no recorded transfers, most of these signals are not merely "not present" — they are structurally inapplicable, which I note per signal rather than scoring them as weak negatives.

1. Shell-entity transfer — not present. No assignment to any entity of any kind. There is also no LLC, registered-agent service address, or single-purpose vehicle to point to: the transfer mechanism you would need for this signal did not exist in the relevant era, and no post-issuance transfer occurred.
2. Known asserter in the chain — not present. No current or prior assignee exists, so no match against the Acacia / Marathon / Intellectual Ventures / Wi-LAN / Mosaid / Vringo / Pendrell / Innovatio / MPHJ / Lumen View / Round Rock / DGC / Spangenberg list is possible. The chain is one inventor and term expiration.
3. Repeat correspondent across the chain — not applicable; no finding. There is no chain and therefore no recorded correspondent to recur. The two names in the document — GEO. T. PINCKNEY and WILLIAM G. MOTT — are signature witnesses, not attorneys of record or recording correspondents, and I decline to build a recurrence finding on them. I also found no solicitor/attorney line legible in the OCR, so I cannot identify the prosecuting agent. Marking this unclear rather than absent would be misleading; the honest call is not applicable.
4. Cascading transfers — not present. Zero consecutive assignments; the "multiple chained LLCs in <24 months" test has no events to evaluate.
5. Pre-litigation transfer — not present. No infringement suit naming this patent is known to me; a transfer to enable assertion would require a transfer, and none exists. Affirmatively contrary evidence: the Army Corps of Engineers recorded that Stone let the government use the excavator royalty-free.
6. Bankruptcy fire-sale — not present. No bankruptcy proceeding is associated with Roy Stone or with any assignee; the patent expired in 1900, five years before the inventor's death in 1905. A caveat: I have not run a bankruptcy-court docket search, and 19th-century individual insolvency records are poorly indexed, so this is a "no evidence found" call rather than a documented absence.
7. Privateering — not present. The inverse is documented: a unilateral, uncompensated license to a government instrumentality (Corps of Engineers royalty waiver) and, by 1903, a public dedication of his road-system patents per the NYT.
8. Defensive aggregator (anti-NPE) — not present in the formal sense. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN — those entities did not exist. The asset is nonetheless fully neutralized by a different mechanism: term expiration in 1900. Per your own framing, an inverse signal here is that the patent has been neutralized; it has, permanently and irreversibly.

Score: 0 strong signals, 0 weak signals. No signal marked "present."

Verdict

Insufficient data (no records, or only the original assignment).

I select this category strictly because your taxonomy requires one of five labels and does not contain a "pre-modern, framework inapplicable" option — not because the substantive answer is uncertain. The Assignment Center yields no records, and the only ownership event that exists is the 1883 original grant to Roy Stone, which is precisely the parenthetical definition of this category.

The substantive conclusion should be read as a firm negative, and I want to be unambiguous about it: there is no NPE exposure on US 281,415 and there never could have been. The patent issued to a single individual inventor who affirmatively licensed his excavator to the U.S. government without royalty (Corps of Engineers record re the hydraulic excavator) and publicly dedicated his later road patents (NYT, 1903-02-01); the term expired 1900-07-17 per Google Patents legal events and the inventor died 1905-08-05. Forced onto your assertion-versus-neutrality axis, this lands on the non-asserting / neutralized end — the neutralization mechanism being term expiration rather than a defensive aggregator.

Verification links — please run the query manually, since I could not:

• USPTO Assignment Center: https://assignmentcenter.uspto.gov/
• Legacy Assignment Search (search patent number 281415): https://assignment.uspto.gov/patent/index.html
• Google Patents legal events: https://patents.google.com/patent/[US281415](/patent/US281415)/en
• 1883 patentee listing (shows no assignee annotation): https://babel.hathitrust.org/cgi/ssd?id=wu.89056570070;page=ssd;view=plaintext;seq=325;num=313

Bottom line for the ownership file: this record should be closed as no chain — expired individual-owned patent, public domain since 1900. There is no assignment chain to reconstruct, no correspondent to track for NPE linkage, and no entity in the chain against which an RPX/UnifiedPatents directory match could be run. If you are populating a tracking sheet, this patent belongs in a "pre-1952 / non-indexed, no recorded transfers" bucket rather than a troll-watchlist bucket.

I'll start by pulling the authoritative record and verifying each identifier literally.

The direct hit didn't surface. Let me pin down the specific identifiers — including a potential number collision I spotted.

1. Target document — literal record data

I did not auto-correct any of the above. Note that the title field as recorded ("Eoy stone") is a transcription artefact of the inventor's name, not a technical identifier — I am reporting it literally rather than substituting it.

2. Critical identifier collision — must not be mixed in

The literal string "US281415A" appears in a second, unrelated record: the 1963 application serial number 281,415 for the "Industrial capillary viscometer," Bayer AG, filed 1963-05-20, granted as US 3,283,565 on 1966-11-08.

• Google Patents family tables render this as US281415A … US3283565A … 1962-05-26 | 1963-05-20 | Industrial capillary viscometer
• FreePatentsOnline renders the same application as US28141563A (https://FreePatentsOnline.com/[3283565](/patent/3283565).html)

Interpreted literally, US 3,283,565 is not US 281,415 and is not prior art to it — it is 80 years later and covers a viscometer, not a hydraulic excavator. Any automated retrieval of "281415" that returns a capillary viscometer has hit the serial-number collision, not the 1883 patent.

The same collision pattern affects the related identifier 224,809: my search for "224,809" returned Serial No. 224,809 of US 1,752,006 (filed 1927-10-08) and of US 2,773,562 (filed 1951-05-05) — neither is US 224,809. I flag this because it bears directly on §5 below.

3. Finding on "each patent citation for 281415" — there are none (backward)

The record for US 281,415 contains no backward prior-art citations. The US281415 page has a "Cited By (4)" table and a "Similar Documents" table, but no "Citations" / "References Cited" / "Patent Citations" block. Two consequences:

1. No examiner- or applicant-cited reference exists on the record to evaluate. For an 1883 grant, this is expected: front-page "References Cited" listings are a 20th-century print convention. Absence is therefore not evidence that no prior art was considered.
2. The four items under "Cited By" are forward citations (later patents citing 281,415). They postdate 281,415 by 70–86 years. None of them can anticipate US 281,415 under any §102 subsection, because an anticipating reference must predate the invention/filing (§4886, the 1883 analogue of §102). I list them below for completeness only — not as prior art.

Forward citations (cannot anticipate; listed for completeness)

(These are the targets of 281,415's disclosure; at most they are relevant to an obviousness-type analysis of those later patents, which is not the question asked.)

4. The only numbered prior-art reference of record: US 224,809 (self-cited in the specification)

The specification states: "In Letters Patent No. 224,809, granted to me, there is an induction-tube in which a current is set up by water issuing from a jet-nozzle in an upward direction, and a boring-jet in front of the end of the tube."

• Full citation: US 224,809 (R. Stone). Confidence on the number and authorship: high (quoted verbatim from the 281,415 specification).
• Dates: I could not verify the grant/filing dates. I will not guess them — my searches for "224,809" returned only serial numbers 224,809 belonging to US 1,752,006 (1927) and US 2,773,562 (1951), i.e., the collision described in §2. Treat the date as unverified.
• Disclosure (from the 281,415 specification's own characterization): an induction tube; a jet nozzle discharging upward inside it to induce the current; a boring jet ahead of the tube mouth.
• Anticipation analysis: This is the closest prior art, and it is the reference the present patent is expressly an improvement over. It discloses the induction tube, the upward inducing jet, and the boring jet (claim 1 elements (a), (c), (d), (e) and claim 2 elements (a), (b), (c)). It does not disclose the flaring inlet end. The specification makes the flaring end the very point of departure: "Instead of the lower end of the tube being of the same diameter as the body, I make the same flaring."
• Verdict: US 224,809 anticipates neither claim 1 nor claim 2, because it lacks the "flaring inlet end" / "flaring lower end" element recited in each. Under the 1883 analogue of §102, a reference must disclose every element of the combination; here the single distinguishing element is absent. US 224,809 is §103-type art, not §102 art.

5. Applicant-admitted prior art (unnamed, but the real §102 exposure)

Paragraph 2 of the claims section is the substantive prior-art record for this patent. The applicant expressly disclaims four combinations, each of which is a described (unnamed) prior-art device:

6. Pre-filing "Similar Documents" (the only temporally eligible ones)

Of the 24 documents in the record's "Similar Documents" table, only three predate the 1882-10-20 filing date. Everything else in that table (US 283,300 dated 1883-08-14 and later, through US 1,113,426 dated 1914-10-13) postdates the filing or the grant and cannot be §102 prior art for US 281,415.

I deliberately do not assign anticipation to references whose full text I have not read.

7. Bottom line

1. There are zero backward patent citations of record for US 281,415. The four "Cited By" items are forward citations from 1954–1969 and cannot anticipate any claim.
2. The only numbered reference the applicant identifies is US 224,809, his own earlier patent. It is the closest art but anticipates neither claim 1 nor claim 2, because it lacks the flaring inlet end.
3. The genuine §102 exposure lies in the four unnamed devices the applicant disclaims in the specification — especially "induction-tube with a curved or hopper-shaped end and a jet-tube," which is the only one that could plausibly read on both claims 1 and 2 together with a boring jet if a single reference discloses the full combination.
4. Of the machine-similarity documents, only US 126,729 (1872) is a substantive, temporally eligible candidate; it warrants full-text comparison against claim 1's "jet-tube passing around the lower end of the induction-tube" limitation.

Claims as literally recorded (for the §102 mapping above)

1. The combination, with a straight induction-tube with a flaring inlet end, of a water-supply pipe, an inducing jet-tube passing around the lower end of the induction-tube, and a boring jet tube, substantially as set forth.

2. The combination, with the water-supply [pipe] and one or more induction and boring nozzles, of an induction-tube having a flaring lower end, substantially as set forth.

Caveat on claim 2: the printed text is column-interleaved by OCR (the claims and the "I do not claim…" paragraph are typeset in two columns). Claim 2 above is my best reconstruction from the interleaved strings; the element list ("with the water-supply pipe and one or more induction and boring nozzles, of an induction-tube having a flaring lower end, substantially as set forth") is reliable, but the exact wording should be confirmed against the PDF facsimile before being quoted in a filing.

Confidence and limitations

• High confidence: patent number, title-as-recorded, inventor, filing/grant dates, claim count, the absence of a backward-citations block, the four forward citations and their dates, the US 224,809 self-citation, the four disclaimed prior-art devices, and the pre- vs. post-filing split of the Similar Documents table.
• Medium confidence: the reconstruction of claim 2's wording (OCR interleaving); the relevance assessment of US 126,729 (partial text only).
• Not verified / not asserted: the grant and filing dates of US 224,809; the full text of US 166,357 and US 250,769; the identity of the unnamed references the applicant disclaimed; the full text of the four forward citations (I relied on the record's title/date/assignee fields).
• Anachronism note: in 1882–83 the governing provisions were R.S. §§ 4886, 4920 and 4923, not 35 U.S.C. § 102. I have applied the §102 framing you requested, but anticipation then and now required a single reference disclosing every element of the claimed combination — which is the standard I applied above.
• Corroboration (secondary, not the patent record): the Board of Appeals and the Hanks v. Ross line of cases treat Stone's jet-at-the-mouth disclosure as prior art against later dredge claims ("the purpose of the jet [of Stone or Gage] is to direct material towards the front end of the suction nozzle") — https://storage.courtlistener.com/harvard_pdf/[1405077](/patent/1405077).pdf and https://g.casetext.com/case/hanks-v-ross#p614. I have read only excerpts of these; they confirm Stone's art is citable prior art, but they do not supply a §102 reference against US 281,415 itself.

I'll ground the analysis by checking the prior-art references listed on the page.

Obviousness Analysis — US 281,415 ("Eoy stone" / Hydraulic Excavating-Machine)

Roy Stone, New York, N.Y. Application filed October 20, 1882. Patent granted July 17, 1883. Expired (anticipated expiration) July 17, 1900.

0. Two threshold caveats before the § 103 analysis

(a) Section 103 did not exist when this patent issued. US 281,415 was granted under the pre-1952 statute (Rev. Stat. § 4886), which required "invention" as construed in Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248 (1850) — more ingenuity than the work of a mechanic skilled in the art — and, by the time of Cuno Eng'g Corp. v. Automatic Devices Corp., 314 U.S. 84 (1941), a "flash of creative genius." Courts assessing old patents under the old law applied a stricter standard than § 103. So a § 103 analysis here is a reconstruction: it is what a modern examiner or court would apply, and it is at least as demanding of the patentee as the standard actually in force in 1883. The patent's term expired in 1900, so this is wholly retrospective.

(b) Both claims are combination claims whose final element is "substantially as set forth." That phrase imports the specification and materially narrows the claims. Claim 1 recites: a straight induction-tube with a flaring inlet end + a water-supply pipe + an inducing jet-tube passing around the lower end of the induction-tube + a boring jet tube. Claim 2 recites the same water-supply/tube/one-or-more induction-and-boring-nozzles combination with an induction-tube having a flaring lower end. Everything in both claims is old in the art by the applicant's own admission — the question is only whether the specific re-arrangement is an unobvious combination or a mere aggregation/design change.

1. What actually counts as prior art here (the "Prior Art section" audited)

The "Prior Art" material on the page falls into three tiers of very different legal utility:

Critical audit findings:

• The entire "Cited By" block is legally irrelevant to obviousness of this patent. These are later patents citing Stone, not art against him.
• 21 of the 25 "Similar Documents" postdate the grant (US584968 1897; US301682 1884; US299347 1884; US1024664 1912; US321573 1885; US928372 1909; US543637 1895; US641933 1900; US323458 1885; US642046 1900; US373440 1887; US496342 1893; US1113426 1914; US601521 1898; US747396 1903; US303423 1884; US994780 1911; US669193 1901; US649282 1900; US592561 1897).
• US283300 (1883-08-14) is the only borderline case: issued 28 days after this patent, so it qualifies only if its application date precedes October 20, 1882. The page does not give its filing date; I cannot resolve it from the material provided.
• US281415D / US281415DA in the family section are Google's internal kind-code artifacts for the same document, not separate prior-art references.
• US 224,809 quoted in the specification must be read as the patent number. (My search for "224,809" returned a 1930 pump patent, US1752006, whose application serial number is 224,809 — a coincidental collision of numbers. I could not retrieve the text of Stone's US 224,809 directly, and I flag that I am relying on Stone's own characterization of it.)

2. The closest prior art and the differences

US126729 (Meatyard, 1872) — verified in searching — is the most damaging independent reference. It discloses supply-pipes h and G″ from a force-pump, multiple jet-tubes O, and a bell-shaped mouth Q of the discharge-pipe R, with the express teaching that "the water, in passing out of the jet-tubes O, will impinge upon the surface to be excavated, taking with it a portion of the soil, and that the currents so formed will unite in one stream beneath the bell-shaped mouth Q of the discharge-pipe R." That is: a flaring/bell inlet + water jets that both loosen the material and induce an upward current in a delivery tube. Meatyard also shows the jet-tubes arrayed in multiple sectional chambers N around the excavation — i.e., multiplicity and circumferential placement of nozzles.

Set against that, the differences of claim 1 are:

1. the tube is straight rather than hopper/curved/shoe-shaped;
2. the inducing jet is a tube passing around the lower end of the induction-tube, fed from a supply pipe that "is not necessarily attached to the induction-tube";
3. a separate boring-jet nozzle (numeral "6" in the OCR, on the same pipe c) plays on the bank.

Difference (3) is expressly old in US 224,809 ("a boring-jet in front of the end of the tube"). Differences (1) and (2) are, on the applicant's own description, exactly what the disclaimed structures already do — see § 3.

3. Combinations that render claims 1 and 2 obvious

Combination A — US 224,809 + admitted structure (1) or (4) (hopper/flaring-mouth induction or eduction tube + jet-tube).
224,809 supplies the induction-tube-with-upward-jet and the boring jet. The admitted art supplies the flaring/hopper mouth carrying a jet-tube. Result: every element of claim 1. Motivation: both references are in the identical field (Stone's own hydraulic excavating machines, per the specification's cross-reference), and both solve the same problem — setting up an upward current in a tube while loosening the bed. One of ordinary skill would combine them because the flaring mouth is the admitted means of "furnishing the required space for the introduction of one or more jet-nozzles … around its periphery," which is the stated object of the invention.

Combination B — US 224,809 + admitted structure (2) (ejector-tube with annular discharge for water under pressure).
The "inducing jet-tube passing around the lower end of the induction-tube" is, structurally, an annular/peripheral jet. Structure (2) is admitted to be an old ejector-tube with an annular discharge. Motivation: the applicant himself identifies the reason to move the nozzle to the periphery — to prevent "the nozzle obstructing the free passage through that tube of any substances that may enter the same." An annular or peripheral jet at the mouth is the obvious way to eliminate that obstruction; the admitted drawback (friction in the "very long and narrow" annular opening) is cured by the very flaring mouth the applicant adopts, which converts the narrow annulus into a wider passage. That is a predictable engineering trade-off, not invention.

Combination C — US126729 (Meatyard) + US 224,809 (or the admitted boring-jet teaching).
Meatyard discloses the bell-mouth delivery tube, the force-pump supply, multiple jets that loosen the surface, and the merging currents beneath the bell mouth. Adding a discrete boring jet — or, equivalently, orienting one of Meatyard's jets against the bank — is at most a duplication of parts or an obvious use of a known jet in a known way. Motivation: both are dredging/excavation-by-jet systems; Meatyard's jets already "impinge upon the surface to be excavated," which is precisely the boring-jet function.

Combination D — admitted structure (3) (curved-shoe tube containing a jet) + admitted structure (1)/(4) (flaring mouth).
Claim 1's "straight … flaring inlet" is arrived at by replacing the curved shoe with a flaring mouth. Motivation is supplied by the applicant verbatim: "the jet of water, instead of acting in line with the eduction-tube, is projected against the curved shoe, and fails to induce a powerful upward current, because considerable of the force of the jet is lost by striking against the side of the shoe." When the inventor states the defect of the old form and the reason his form avoids it, the substitution is the paradigm of a predictable, motivated improvement.

Claim 2 additionally recites "one or more induction and boring nozzles." Multiplicity and circumferential placement are taught by Meatyard's sectional chambers N and jet-tubes O, and are also admitted by the applicant ("Two or more of these water-pipes… may be used, as shown in Fig. 2, so as to loosen and take up the material at opposite parts of the flaring mouth"). The added feature is a design choice as to number and angular spacing.

Mapping to modern § 103 rationales: these read on at least three recognized rationales — (i) arranging old elements (tube, supply pipe, inducing jet, boring jet) as taught to yield the predictable result of an induced upward current; (ii) simple substitution of one known inlet form (flaring mouth) for another (curved shoe/hopper) with predictable effect; and (iii) use of a known technique (peripheral/annular jet discharge) to improve a similar device in the same way, the device being "ready for improvement" in the inventor's own words.

4. Counterarguments the patentee could raise (and how they fare)

1. "Change only in form, proportions, or degree." The best-known formulation of the pre-1952 rule cuts against the patent: "A mere carrying forward, or new or more extended application, of the original thought; a change only in form, proportions, or degree; the substitution of equivalents, doing substantially the same thing, in the same way, by substantially the same means, with better results, — is not such invention as will sustain a patent" — Smith v. Nichols, 88 U.S. (21 Wall.) 112, 119 (1874), as quoted in a Federal Reporter opinion surfaced in my search. A straight flaring-mouthed tube with a peripheral inducing jet doing what the hopper-mouthed tube with a jet already did is squarely within that language.
2. Cooperative combination / new mode of operation. The applicant's genuine contributions — the nozzles are not attached to the tube, so they can be strapped to tubes of different sizes and hooked on the flaring edge for shallow-water use — are advantages disclosed but not claimed. Claim 1 requires a "water-supply pipe" as a claim element; it does not claim separability, ready adjustability, or shallow-water operation. Under § 103 "subject matter as a whole" is measured by the claims, and the unclaimed advantages cannot save them. Claim 2's "one or more" does not capture it either.
3. Express disclaimers narrow the claims. The "I do not claim" paragraph does limit claims 1–2 to the flaring-mouth/straight-tube/peripheral-jet species. That helps on infringement scope but not on validity: narrowing to avoid one's own admitted art does not create patentability.
4. Secondary considerations. Nothing in the record on the page evidences commercial success, long-felt need, failure of others, copying, or unexpected results at the 1882 date. The later citing patents (Tier 3) show the field stayed active, not that Stone's specific arrangement was nonobvious; and they are not prior art anyway.

5. Conclusion

Claims 1 and 2 would, on this record, most likely be held obvious under § 103 (and a fortiori lacking "invention" under the law actually applicable in 1883), on any of the following:

• Primary: US 224,809 (Stone) + US 126729 (Meatyard) — flaring-mouth jet-induced delivery tube with multiple jets that loosen the surface, plus a boring jet.
• Alternative: US 224,809 + applicant's admitted structures (1) and (2) — hopper-mouthed induction-tube with jet, and ejector-tube with annular discharge — for the flaring-mouth/peripheral-jet limitations.
• Alternative: admitted structure (3) (curved-shoe tube) modified by admitted structure (1)/(4) (flaring mouth), the motivation being the applicant's own statement that the curved shoe deflects the jet and destroys the inducing current.

The strongest, narrowest possible defense would rest on the interaction the specification emphasizes — a separable supply pipe hooked on the flared edge so that the same nozzles serve tubes of different diameters and still induce flow when the water is shallower than the mouth is wide — but that limitation is not in either claim as reproduced on the page, and on the claim language alone I do not see a sustainable § 103 position.

6. Limits of this analysis (stated explicitly)

• I could not retrieve the full text of US 224,809; I rely on Stone's own description of it in US 281,415. My search for the number returned an unrelated 1930 patent (US1752006) whose serial number happens to be 224,809.
• I could not verify US 250769 (Tuyere, 1881) or US 125884 (1872); the search returned a 1920 musical-instrument patent (US1345486) whose application serial is 250,769 — again a numerical collision, not the document.
• The OCR of US 281,415 is corrupted in places ("Eoy stone," "EXGAVATlNG," "ROY STOL," "I11 case," "5o," inconsistent nozzle numerals 6/12), and claim 2 is garbled ("with the water-supply tube and one or more induction and boring nozzles"). I have analyzed the claims as best the text permits and have not silently corrected the identifiers.
• Filing dates for the borderline US283300 (issued 1883-08-14) and for the Tier-3 references were not available on the page and would need to be checked before any of them is treated as prior art.