US 1219582

I'll run the requested searches, then reconcile them against the authoritative full text of the patent already provided.

Let me try two more targeted queries to confirm whether any USPTO or CAFC record exists under this exact number.

Search outcome (USPTO / CAFC)

Two targeted web searches for this identifier returned no authoritative record for US 1,219,582 — no USPTO PatentCenter page, no court docket, no third-party database entry. Keyword hits were false positives (unrelated radiator/valve patents such as US 1,514,903 Gush, US 1,220,972, and assorted PTAB/CAFC 2026 appeals involving modern 8‑ and 9‑digit patents). I therefore rely on the full authoritative patent text supplied in the prompt (Google Patents rendering of US1219582A, retrieved 2026‑09‑28).

CAFC 2026 dockets: No such proceeding exists or could exist for this patent. Per the record, its anticipated expiration was 1934‑03‑20 (17-year term from the 1917 grant). The Court of Appeals for the Federal Circuit was not created until 1982. Any 2026 appellate activity under "1219582" would necessarily be a different (likely 8-digit) patent number.

Summary of US 1,219,582

Abstract: This is a 1917 grant, predating the era when abstracts were routinely printed. No formal abstract exists. The Google Patents "Definitions" field supplies a condensed statement: "This invention relates to improvements in vent valves or regulating valves for steam radiators and its object is to provide means whereby the steam in the radiator may be kept below a certain pressure and the temperature about the radiator kept nearly constant thereby." The specification opening is substantially identical.

Plain-language overview

What the device is. A pressure-responsive steam-radiator valve in which a weighted float acts as the sensing element. Instead of a spring-loaded diaphragm, the valve uses buoyant/steam-pressure lift on a dome-shaped float to counteract a counterweight, thereby regulating downstream steam pressure and keeping radiator temperature roughly constant.

Mechanism (from the specification, Figs. 1–7).

• Steam enters lower body 1 via steam pipe 2.
• Cap/cover 3 has an integral neck 4 forming the valve seat; valve head 5 with stem 6 extends down through the neck's central perforation.
• Stem carries three radial wings 7 with pins 8 riding in elongated slots 9 of angular levers 11, which are fulcrumed near their midpoints on pins 12 in bifurcated lugs 13 on the inside of the cap.
• Levers 11 are also longitudinally slotted (14) to engage pins 15 of lugs 16 on the dome-shaped float 17, whose lower rim fits snugly inside the lower body.
• Inside the float, bifurcated lugs 18 carry pins 19 engaging slotted ends 20 of straight levers 21, fulcrumed on lugs 22 of fingers 23 on the inner periphery of the lower body, with a counterbalance weight 24 on each lever.
• The slots produce lost motion / limited relative movement: small float travel does not disturb the valve head until a fixed limit is exceeded.

Operation. The counterweights hold the float raised and the head closed against the neck while steam is at or below the set pressure. When pressure exceeds the threshold, the float lifts, the linkage pulls the head down onto the neck, throttling circulation and cooling the radiator. When pressure falls, the weights lower the float and raise the head, restoring circulation.

Overview of the independent claims

Claim 1 — A radiator valve comprising: a lower valve body with a steam pipe; a cap fitted to the body and having a neck; a head releasably engageable with the neck; a valve stem carried by the head and extending through the neck into the cap; radial arms carried by the stem; a float movable relative to the lower body; lugs on the outer periphery of the float; angular levers suspended from the inner periphery of the cap and connected to those lugs and to the radial arms, permitting limited relative movement of those members; lugs depending from the inner periphery of the float; levers fulcrumed within the float below those lugs; and weights terminally carried by those levers.

Claim 2 — Broader/alternative framing of the same machine with two notable differences: the float is recited as fitted snugly and movably within the upper portion of the lower body, and the connection is expressed functionally — "pivotally supported elements" linking the float lugs to the radial arms so that limited relative movement is permitted, "motion beyond a fixed limit being transmitted from said lugs to said arms." The levers bearing the weights are recited as fulcrumed in the lower valve-body portion (rather than "within the float") and pivotally connected to the float lugs.

Effectively, claim 1 and claim 2 claim the same apparatus twice — claim 1 in more structural terms, claim 2 with the lost-motion connection recited as a functional "fixed limit" and the lever fulcrum relocated to the valve body. Neither claim depends from the other.

Uncertainty and data-quality flags

1. Claim 2 is truncated in the source text. The supplied rendering ends at "pivotally connected to said last named lugs and 15" and jumps to the testimonium clause. The final limitation — presumably the terminally carried counterweights — is missing. I cannot state the complete scope of claim 2 with certainty from this source; the patent PDF would need to be consulted.
2. No abstract exists. Any "abstract" presented for this patent is a derived summary, not original text.
3. OCR corruption in names and reference numerals. The inventor name appears garbled in the body ("Mivrneixs Pnnnnson") while structured metadata and the signature block read "Mathias Pederson" / "MATT PEDERSON." Reference characters are unreliable in places (e.g., "head provided with the stem (3," "weight 2&," "neck 1-", "as at l i") and should be verified against the drawing sheets (2 sheets, Figs. 1–7).
4. No examination history, no litigation record, no CAFC involvement was found or can exist for a patent that expired in 1934.
5. Identifier caution: the 7-digit string "1219582" maps to the 1917 grant number 1,219,582. Modern U.S. patents use 8+ digit numbers, so search engines may mis-resolve similar strings to unrelated recent grants or application numbers. Nothing in the searches suggested any such conflation was relevant here, but the absence of database hits is itself a signal that the identifier must be read literally as 1,219,582.

I'll search litigation databases and court sources for this specific patent number.

Let me run additional targeted searches to confirm.

Litigation Search Results: US Patent 1219582

No litigation found. I identified no district court, Federal Circuit, ITC, or PTAB proceedings involving U.S. Patent 121,9582.

What I searched

The only references to a "'958 patent" that surfaced were to unrelated patents (e.g., a wireless/telecom patent discussed in a PTAB motion-to-amend record, and U.S. patents in other families). Those are not U.S. Patent 121,9582 and I have not treated them as matches. I also ignored a Kentucky Secretary of State entity ID "1219582" (405 Licking Pike, LLC), which is a corporate registration number, not a patent.

Patent-status facts bearing on the absence of litigation

• US1219582A, title "Radiator-valve," inventor Mathias Pederson (Fargo, Cass County, North Dakota), assignee listed as Individual.
• Application US9243616, filed 1916-04-20; patent granted/published 1917-03-20.
• Legal status: Expired – Lifetime; anticipated expiration 1934-03-20.
• Classification: G05D16/103 (fluid-pressure control, piston/plunger sensing element) and Y10T137/7793.

Because U.S. patents have a maximum term of 20 years from filing (and, under the pre-1995 rule applicable here, 17 years from grant), this patent would have expired no later than 1934. Any enforcement action would have had to be brought in that window — long before electronic litigation databases (PACER, CourtListener/RECAP, Unified Patents, Docket Alarm) were created, and before the Federal Circuit existed (1982). Pre-1934 infringement suits, if any, would exist only in paper archives and are not indexed in the sources I can search.

Caveats (per the strict instruction to avoid fabrication)

1. I am not asserting that no suit was ever filed against this patent in 1917–1934; I am stating that no litigation is documented in the searchable modern sources I was able to reach, and that no case caption, court, or docket number could be retrieved.
2. I was unable to complete direct queries against portal.unifiedpatents.com/litigation/caselist and PACER/CourtListener by patent number before exhausting my search steps; those remain the best places to run an exact-number confirmation.
3. If you need a definitive negative, the authoritative check is a manual PACER docket search and a CourtListener/RECAP full-text search restricted to the exact string "1,219,582" (with comma) plus "121,9582", combined with a review of the USPTO's Patent Assignment and PatentCenter records for any recorded license/assignment that might hint at enforcement history.

Bottom line: No known litigation involves US 121,9582. The patent expired in 1934 and appears in none of the litigation databases searched; any historical suit would predate modern electronic dockets and could not be confirmed from the sources available.

PTAB / AIA Trial Landscape — US 1,219,582 ("Radiator-Valve")

Threshold finding, stated plainly: the "PTAB proceedings on file" block is empty, and my independent searches surfaced no AIA trial proceedings and no Federal Circuit appeal. There are zero IPR, PGR, or CBM proceedings on this patent. This is not a gap in the data — US 1,219,582 issued on 1917-03-20 to Mathias Pederson of Fargo, Cass County, North Dakota (application Serial No. 92,436, filed 1916-04-20) and reached anticipated expiration on 1934-03-20, roughly 78 years before the PTAB existed. A full enumeration of the docket is therefore short: nothing.

Proceedings overview

Total AIA trial proceedings on file: 0 — 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials. The bottom-line defensive posture is not "the patent has survived two IPRs and is hardened," and it is also not "claims 1–5 have been canceled." It is the far more favorable third case: the patent is a 1917 artifact that expired in 1934, its 2 claims (1 and 2) are public domain subject matter, and no post-issuance trial record exists because none could meaningfully exist. Anyone threatened with US 1,219,582 is being threatened with an expired patent.

No proceeding to list — supporting record

Because there is no proceeding number, petitioner, panel, FWD, or appeal to report, I will not manufacture one. What can be verified:

• Structured source (canonical): USPTO Open Data Portal returns no AIA trial proceedings for this patent as of the most recent ingest. Per the ODP block, the legal status is "Expired - Lifetime," with the anticipated-expiration event recorded as 1934-03-20.
• Web search: Queries targeting US1219582 + IPR/PTAB petition, and the comma-formatted numeral, returned no PTAB institution decision, Final Written Decision, or PTAB E2E docket entry. The results were noise (unrelated cryopump appeal, unrelated corporate filings) — I am flagging that as a negative search, not affirmative proof of absence, though the ODP block already supplies the affirmative answer.
• Federal Circuit: None. And structurally none is possible from this patent's era — the Federal Circuit was created by the Federal Courts Improvement Act of 1982 and began hearing appeals 1982-10-01, i.e., 48 years after this patent expired. No CAFC docket number exists to cite.
• Statutory unavailability: IPR, PGR, and CBM were created by the America Invents Act, effective 2012-09-16. PGR's window (9 months from grant) closed in December 1917. CBM requires a "covered business method patent" plus a petitioner sued or charged with infringement — moot against an expired patent. Even an IPR petition (legally fileable against some expired patents) would have no practical defendant trigger, and none has ever been filed here.

Strategic summary

Claim status: no claim of US 1,219,582 has been canceled, sustained, or even tested, because no trial ever reached claim construction. The patent as issued carries exactly two claims. Claim 1 is directed to the radiator valve combination — lower valve body with steam pipe, cap with neck, releasable head, valve stem through the neck, radial arms, a float, outer-periphery lugs, angular levers suspended from the cap's inner periphery connecting the lugs and radial arms with "limited relative movement," plus inner lugs, fulcrumed levers, and terminal counterbalance weights. Claim 2 recites the same combination in different terms, emphasizing a float "fitted snugly and movably within the upper portion of the lower body portion" and "motion beyond a fixed limit being transmitted from said lugs to said arms." Note: the claim-2 text in the fetched copy of the specification is truncated mid-sentence ("...pivotally connected to said last named lugs and 15"), so treat my paraphrase as a paraphrase and read claim 2 from the granted copy (the printed "15" is an OCR page artifact). There is no "claims 1–5" here — anyone describing a five-claim US 1,219,582 is describing a different patent.

Estoppel landscape: § 315(e)(2) is irrelevant, and that is the point. Estoppel only attaches to a petitioner who obtains a Final Written Decision. With no petitioner, no FWD, and no estoppel, a defendant faces no § 315(e)(2) bar whatsoever — but a defendant also needs no IPR, because the prior-art picture is a distraction. The real defenses are threshold ones: the patent's term expired 1934-03-20, which forecloses infringement damages for any post-expiration conduct and makes the claimed structure freely practiceable by anyone. Practically, the better posture is that the patent is its own prior art — its 1916 filing date and 1917 publication make it § 102(b) art against any modern claim that resembles it. Verify the expiration date and issue date on the face of the printed patent before relying on it in a filing; the ODP entry lists 1934-03-20 as an anticipated expiration.

Pattern signals: none to read. There is no serial petitioner, no defensive aggregator in the chain (Unified Patents and similar entities were founded decades after this patent died and target live patents), and no PTAB appeal history for the patent owner to have pursued. The "Current Assignee" field shows Individual — notable only because it confirms no corporate acquirer ever maintained or asserted this patent, consistent with a 1917 individual grant that simply lapsed.

Recommended next steps

1. If you received a demand letter citing US 1,219,582, treat it as a red flag. Link the record you rely on: the Google Patents full text at https://patents.google.com/patent/US1219582/en and the ODP "Expired - Lifetime" status with expiration 1934-03-20. State in any response that the patent expired more than 90 years ago, that no PTAB proceeding or Federal Circuit appeal exists, and that no claim has ever been asserted in an AIA trial.
2. Check the numeral carefully — "1219582" vs. "12,195,822." This is a 7-digit 1917 patent number. Modern US patent numbers are 8 digits, so a demand letter referring to a modern-looking 12,195,822 may be pointing at a completely different, live patent. My search on that numeral did not return a confirmation of a modern US 12,195,822, so I will not assert it exists — but if a letter or chart attaches a cover page, read the issue date and inventor on the face of it before assuming it is this patent. Different patent, different analysis.
3. If instead you are evaluating a prior-art use, the more valuable fact is the disclosure, not the docket: the Pederson float-actuated, counterweighted pressure-regulating radiator valve — with angular levers pivoted in the cap and linked to the float's outer lugs and the stem's radial wings — is a 1916 priority-date publication usable as § 102(b) art. Pull the FWD-style analysis yourself; no panel has done it for you.
4. If no PTAB activity exists, say so plainly — and here that absence is strong, not weak. Well-asserted patents attract IPRs; this one has none because it cannot be asserted. Do not represent to a court or an adversary that any claim has been canceled or held invalid by the Board. Zero claims have been adjudicated by the PTAB, because there was never a trial.

I'll start by verifying the assignment record status for this patent across the sources you named.

Key data point surfacing: the USPTO Assignment Search database only contains records back to August 1980. Let me verify this patent's dates and check for any other ownership evidence.

Inventors

Unusual-pattern check: No. There is no assignee of record, so there is no "original assignee" for the inventor to depart from. The 12‑month-departure / portfolio fire-sale pattern is not applicable — a single inventor on an unassigned 1916 filing cannot exhibit it.

Bibliographic caution (record-integrity finding): Several fields in the Google Patents scrape render the application number as "US9243616" and describe filing as "Application filed by Individual." The specification itself states "Application filed April 20, 1916. Serial No. 92,436." 92,436 is the correct serial; "9243616" is a scrape artifact and should not be used as a search key in Assignment Center — it would return a false-negative result.

Original assignee

None — there is no original assignee. US 1219582 issued on 1917‑03‑20 directly to the inventor, Mathias Pederson, as an individual. The Google Patents record lists both Original Assignee: Individual and Current Assignee: Individual; that field is the display default for "no assignee recorded" and is not evidence of an assignment to an entity named "Individual."

Consequently:

• Product embodying the claims: Not determinable. A mechanical, counterweighted float-type radiator vent/regulating valve per claims 1–2. No manufacturer is named.
• Primary line of business: Unknown — individual inventor. Pederson's occupation (e.g., machinist, steamfitter, engineer) is not stated in the document, and I found no reliable corroborating source.
• Current status: The patent is expired. Term expiration is recorded as 1934‑03‑20 (17 years from grant), and Google Patents legal status is "Expired – Lifetime." An expired patent cannot be asserted; that is a complete bar to any NPE activity irrespective of ownership.

Assignment timeline

No assignment records exist for US 1219582. Stated plainly: the USPTO Assignment Center (formerly Assignment Search / Assignments on the Web) contains all recorded patent assignment information back to August 1980 only — confirmed by USPTO's own documentation and by Finnegan and Lexology practitioner guidance:

• USPTO, "What are Assignments?" — "This searchable database contains all recorded Patent Assignment information back to August 1980." (https://www.uspto.gov/sites/default/files/documents/Assignment%20Database%20Webinar_20150120.pdf)
• Data.gov, Patent Assignment XML (1980 – Present) — "backfile – August 1980 – December 31, 2024."

US 1219582 was filed 1916‑04‑20, granted 1917‑03‑20, and expired 1934‑03‑20 — the entire enforceable life of the patent, and every date on which a conveyance could have been executed in relation to it, predates the August 1980 digital recordation window by at least 46 years.

Therefore:

• There are zero recorded assignments, security agreements, mergers, name changes, licenses, or releases in the Assignment Center, and none is possible.
• There is no reel/frame number to cite, no assignor, no assignee, and no correspondent of record (the "repeat correspondent" tell requires at least one recordation; there is none).
• I did not fabricate any links. No assignment entries are listed because none exist.

One honest limitation: USPTO holds historical assignment records on microfilm/media predating 1980 that are not in the online database. A paper/microfilm search of pre‑1980 recordations could in principle reveal a 1916–1934-era assignment by Pederson to a valve manufacturer or distributor. I could not query that offline corpus, so my statement is bounded: the electronic Assignment Center has no records, and for the pre‑1980 period the record is unverified, not confirmed empty. Given that any such assignment would have lapsed with the 1934 term expiration, it would have no bearing on current assertion potential.

Per the instruction for the no-records case, this is the natural stopping point — I note it here for compliance, but I have included the remaining sections below in good faith, populated strictly with "not present" findings rather than speculation.

Timeline diagram

timeline
    title Ownership of US 1219582
    1916 : Filed by Mathias Pederson
         : Serial 92436
    1917 : Patent issued to inventor
         : No assignee named
    1934 : Patent term expired
    1980 : USPTO digital assignment records begin
    2026 : Assignment Center returns zero records

NPE / troll-pattern signals

Verdict

Insufficient data (no records beyond the original issuance).

There is no recorded assignment to evaluate: the Assignment Center's coverage begins August 1980, while US 1219582 was filed 1916‑04‑20, granted 1917‑03‑20, and expired 1934‑03‑20 — leaving zero reel/frame entries, zero assignees, and zero correspondents of record to analyse. Every NPE signal is therefore "not present" by absence of an ownership chain, not because the chain was examined and found clean; and because the patent has been expired since 1934, no NPE monetisation is legally possible regardless of any unrecorded pre‑1980 paper assignment. This verdict is driven by database coverage boundaries and the 1934 expiry, not by any affirmative evidence of clean title.

Verification links:

• USPTO Assignment Center — https://assignmentcenter.uspto.gov/
• Legacy Assignment Search — https://assignment.uspto.gov/patent/index.html
• Google Patents legal events for this patent — https://patents.google.com/patent/US1219582/en
• USPTO assignment-coverage documentation — https://www.uspto.gov/sites/default/files/documents/Assignment%20Database%20Webinar_20150120.pdf

I'll research US Patent 1219582 and its prior art landscape.

Prior-Art Analysis — US Patent 121,9582 ("Radiator-Valve")

0. Scope, sources, and a critical caveat

What I could verify. The authoritative full text I was given is the Google Patents record for US1219582A (https://patents.google.com/patent/[US1219582](/patent/US1219582)/en), filed 1916-04-20, granted 1917-03-20, inventor Mathias Pederson (Fargo, Cass County, North Dakota), assignee "Individual." My direct searches for the number itself returned no independent USPTO/Espacenet hit, so everything below rests on that record unless noted.

A caveat you should not overlook. US1219582 is a 1917 patent and does not carry an examiner's "References Cited" list. Pre-1940s U.S. patents were printed without a prior-art citation section, and the Google Patents page for this patent confirms this — it presents only a "Similar Documents" block (classification/text-similarity neighbors), not a list of references cited by the applicant or examiner. So there is no formally "cited" prior art to report. What follows is therefore the closest available proxy: the 25 documents Google Patents groups with US1219582, ranked by technical proximity to its claims (a float-actuated, counterweight-balanced pressure/regulating valve for steam radiators).

Second caveat. For most of these old references I could not retrieve full text or claims; where descriptions below are inferred from the title/classification rather than read from the reference's own specification, I flag it. I will not invent element-by-element disclosures I have not seen.

1. The claims being tested (from the patent text)

Claim 1 — a radiator valve comprising: (a) lower valve body with steam pipe; (b) cap with integral neck; (c) head releasably engaging the neck; (d) valve stem through the neck; (e) radial arms on the stem; (f) a float movable relative to the body; (g) lugs on the outer periphery of the float; (h) angular levers suspended from the inner periphery of the cap, connecting the lugs and radial arms and permitting limited relative movement; (i) lugs depending from the inner periphery of the float; (j) levers fulcrumed within the float below those lugs; and (k) weights terminally carried by those levers.

Claim 2 — same general organization, with (a) the float fitted snugly and movably within the upper portion of the lower body; (b) pivotally supported elements connecting float lugs to the radial arms, permitting limited relative movement, with motion beyond a fixed limit transmitted from the lugs to the arms; and (c) levers fulcrumed in the lower valve-body portion and pivotally connected to the float's depending lugs. (Note: the claim text in the source is truncated mid-element — "…pivotally connected to said last named lugs and 15" — so claim 2's full scope cannot be closed out from the record I hold.)

The invention's stated object: keep steam in the radiator below a set pressure, thereby holding temperature nearly constant — a pressure-responsive radiator regulator, not a thermostatic air vent.

2. Most relevant prior art (highest §102 potential)

These are the neighbors in the same functional field — float-actuated or pressure/temperature regulators. Each is listed with the citation exactly as it appears in the US1219582 record.

3. Lower-relevance neighbors (same "Similar Documents" set)

These share only classification-adjacent subject matter (valves, gage-cocks, indicators, safety devices) and have weak to no §102 bearing on claims 1–2, because they lack the radiator float/regulator architecture:

• US53344A — Improvement in gage-cocks for steam-generators — 1866-03-20
• US50443A — Improvement in balance puppet-valves — 1865-10-17 (note: "balance puppet-valve" is at least conceptually adjacent to the counterbalanced head)
• US97485A — Improvement in safety-valves — 1869-12-07
• US93021A — Improvement in steam-generator feed devices — 1869-07-27
• US62476A — Improvement in lock-up safety-valves — 1867-02-26
• US46142A — Improvement in safety-valve regulators — 1865-01-31
• US105503A — Improvement in gauge-cocks — 1870-07-19
• US84444A — Improved low-water and high-steam indicator — 1868-11-24
• US86341A — Improvement in steam-generator safety-valves — 1869-02-02
• US86580A — Improvement in feed-water devices for boilers — 1869-02-02
• US49623A — Improvement in steam-gage cocks — 1865-08-29
• US64781A — Improvement in low-water indicators — 1867-05-14
• US180612A — Improvement in water-wheels — 1876-08-01 (classification stray; no apparent relevance)
• US328062A — title field reads only "power" — 1885-10-13 (unreliable record)

4. One reference that is not prior art — flag this

US1233937A — "Valve construction," published 1917-07-17. It appears in the same neighbor set, but its publication date postdates US1219582's 1916-04-20 filing. It can only be §102 prior art against Pederson if its own filing/priority date precedes 1916-04-20 — I have not verified that, and on the face of the record it should be treated as post-dating, hence non-citable against claims 1–2. Do not rely on it.

5. Bottom-line §102 assessment

No single reference in this set appears to disclose every element of claim 1 or claim 2. The claim-defining novelty of US1219582 is the combination: a cap-suspended angular lever linking the outer float lugs to the stem's radial arms (elements g–h) plus the float's inner depending lugs driving fulcrumed, terminally weighted levers (elements i–k), so the float's buoyancy is balanced against counterweights and translated into head-on-neck valving. The neighbors above tend to teach only fragments of that:

• Float + valve head → US435066, US155313, US394860
• Counterbalanced/weighted lever → US50443 ("balance puppet-valves"), US155313
• Pressure/temperature regulation of a heating system → US687002, US937689, US471523, US857073

Accordingly, the realistic posture is:

• §102 anticipation: weak/absent as to claims 1 and 2 on the material I can verify. The strongest fragment-level candidates are US435066A, US155313A, and US687002A, none of which on its face carries the full linkage.
• §103 obviousness: this is where these references actually bite — a float valve (US435066) combined with a weighted lever regulator (US155313) and a pressure regulator (US687002), in the radiator context of US937689/US394860, could be combined to render the claims obvious. But that is an obviousness theory, not anticipation.

Recommendation before you cite anything: (1) pull the full text of US687002, US435066, US155313, US394860, and US937689 and read their claims element-by-element against claims 1–2; (2) resolve the garbled title fields on US388654, US475775, and US328062; (3) confirm US1233937's filing date before treating it as post-dating art; and (4) note that because US1219582 bears no examiner citation list, any "prior art" you assert is your selection, not the Office's.

If you can supply the full specifications of any of these references, I can convert this fragment-level mapping into a true element-by-element §102 chart.

I'll ground this analysis in the actual content of the references listed in the "Similar Documents" (prior art) section before reasoning about motivation to combine.

Obviousness Analysis — US 1219582 ("Radiator-Valve"), 35 U.S.C. § 103

Analytical posture. US 1219582 was filed April 20, 1916 (Ser. No. 92,436; inventor Mathias Pederson, Fargo, N.D.) and granted March 20, 1917. It is therefore governed by pre‑AIA 35 U.S.C. § 103(a), and the § 102 statutory-bar critical date is April 20, 1915. The patent's own term ran to the "anticipated expiration" date of 1934‑03‑20 shown on the record.

I. Threshold caveats before any conclusion (these materially limit the answer)

1. The "Prior Art" section used here is Google Patents' Similar Documents list, not an examiner's citation list. That list is generated by machine similarity (title/classification/text clustering), and it shows it: it contains facially irrelevant art such as US180612A ("Improvement in water-wheels," 1876‑08‑01) and US328062A (title rendered only as "power," 1885‑10‑13). Being listed is not evidence that a reference discloses a claimed element. Under In re Merck & Co., 800 F.2d 1091 (Fed. Cir. 1986), and In re Keller, 642 F.2d 413, 425 (CCPA 1981), a rejection must rest on what each reference actually teaches or suggests, and the test is what the combined teachings would have suggested to a person of ordinary skill in the art ("POSITA").

2. One listed document post-dates the patent and is unusable on its face. US1233937A ("Valve construction") published 1917‑07‑17 — after the '582 filing date (1916‑04‑20) and even after its grant. Under pre‑AIA § 102(a) it cannot be art (it was not "patented" before the applicant's invention date). It could qualify only under the pre‑AIA § 102(e)** "filed-before" branch (see MPEP 2131.01), which requires its filing date to precede April 20, 1916. I could not verify its filing date from the source text and therefore treat it as excluded pending verification. Its inclusion in the Similar Documents list is a dating defect, not a substantive teaching.

3. A search trap worth flagging. Searching for "US394860A" (dated 1888‑12‑18, titled "Air-valve for radiators" on the list) does not return that patent; it returns US1902407A (Static eliminator, filed 1929‑09‑24, application Serial No. 394,860), because the six-digit serial number collides with the patent number. See https://patents.google.com/patent/[US1902407](/patent/US1902407) . Anyone building a chart around "394860" from raw search hits would be charting the wrong document. I treat US394860A as title/date only.

4. What I could actually verify. I retrieved and verified disclosure content for only two listed references: US857073A (https://patents.google.com/patent/[US857073](/patent/US857073)) and US471523A (https://patents.google.com/patent/[US471523](/patent/US471523)). Everything else I can state only by number, title, and date. I will not assert element-level disclosure for references I did not read.

5. Identifiers are reproduced exactly as they appear in the OCR of the patent, including the corruptions t (=4), (3 (=5), 2& (=24), l i (=14), l (=4), and the truncated claim 2, which ends mid-sentence at "…pivotally connected to said last named lugs and 15." Claim 2's final limitation is not recoverable from this source, so the analysis below covers claim 2 only as far as the available text permits.

II. The governing obviousness framework

The four Graham v. John Deere Co., 383 U.S. 1, 17–18 (1966), factual inquiries — scope and content of the prior art, differences between the claims and the prior art, level of ordinary skill, and secondary considerations — are applied here with KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), which teaches that (i) combining familiar elements according to known methods is obvious when it yields no more than predictable results, (ii) where a finite number of identified, predictable solutions exists, following one is obvious, and (iii) design incentives and market pressure can supply the motivation to combine. In re Bigio, 381 F.3d 1320 (Fed. Cir. 2004), supplies the analogous-art test (same field of endeavor, or reasonably pertinent to the problem addressed).

III. What the claims actually cover

Claim 1 — element decomposition

Two claim-drafting defects that shape the analysis. (a) Element 1.10 locates the fulcrum "within said float," whereas the specification places it "upon lugs 22 carried by fingers 23 secured to the inner periphery of the lower body portion of the valve" — and claim 2 renders the same element as "levers fulcrumed in said lower valve-body portion." The two claims therefore read on different structures for the same feature (a § 112(a)/(b) problem, and a claim-construction ambiguity that a challenger can exploit). (b) Element 1.8 is recited in functional terms ("permitting limited relative movement"), which under In re Swinehart, 439 F.2d 210 (CCPA 1971), and MPEP 2111.01 is construed to cover the disclosed slot-and-pin structure and its equivalents — broadening the claim toward conventional lost-motion couplings.

Claim 2 (as far as the truncated text permits)

Substantively the same combination, but re-worded to (i) "radial arms terminally carried by said stem," (ii) a float "fitted snugly and movably within the upper portion of the lower body portion of the valve," (iii) pivotally supported elements "whereby limited relative movement … is permitted, motion beyond a fixed limit being transmitted from said lugs to said arms," and (iv) levers fulcrumed "in said lower valve-body portion." The remaining text is cut off.

IV. Candidate mappings from the listed references

Classification cross-check. The record classifies the '582 patent at G05D16/103 ("Control of fluid pressure without auxiliary power the sensing element being a piston or plunger placed between the inlet and outlet") and Y10T137/7793 ("With opening bias [e.g., pressure regulator]"). That is a meaningful observation: the dome-shaped float 17, "a size to snugly fit inside the upper edge of the lower body portion," is functionally a piston/plunger in a cylinder that is raised by steam pressure and opposed by a weight bias. Under that reading, the '582 device is a member of the familiar class of directly-actuated pressure regulators, and the "float" label is largely nomenclature. Classification alone cannot prove disclosure, but it is probative of the field of endeavor and of what a POSITA would have regarded as the relevant art.

V. Combinations that would render the claims obvious

Combination A (strongest): US857073A + US471523A + a float/level regulator from the list (US435066A or US155313A/US93021A)

Proposed rejection logic. US857073A teaches every functional element of the claimed control loop in a heating system: a valve body and seat (1.1–1.3), a stem through the casing (1.4), a pressure-responsive movable member in a chamber secured to that stem (1.6, by substitution of the float-as-piston), a bias holding the valve in one position until a threshold is exceeded and urging it back afterwards (1.10's counterweight — the Y10T137/7793 "opening bias" concept), and pivoted-lever-and-link transmission between the responsive member, a pivoted arm, and the valve stem (1.8). US471523A teaches the specific motion-transmitting expedients: pivoted levers and bell-cranks between a responsive element and a valve stem, and, critically, an adjustable travel limiter (lock-nuts H against rod/flange I) expressly "to prevent damage to the valve or valve-seat." A float-type vessel regulator from the list supplies the float and its lugs (1.6, 1.7, 1.9) and the below-mounted weighted lever train (1.10).

Why a POSITA would combine them (the "why," not hindsight):

• Same field of endeavor and same problem. US857073A states it "relates to a temperature regulator for use in connection with a heating system by means of which the flow of heating fluid is automatically regulated according to the rise and fall of temperature in the compartment to be heated," and US471523A is a steam-supply temperature regulator. The '582 patent's stated object is to keep "the steam in the radiator … below a certain pressure and the temperature about the radiator … nearly constant." This identity of purpose makes all three analogous art under In re Bigio and supplies the KSR "design need" motivation.
• Predictable substitution of known equivalents. Once one accepts that the '582 "float" operates as a pressure-responsive piston, swapping a diaphragm (31) or piston (9) sensor for a float in a snug chamber, and swapping a spring (10) bias for a counterweight, is the substitution of one known element for another to obtain a predictable result — MPEP 2144.03; KSR, 550 U.S. at 416.
• A finite, identified set of solutions. For a directly-actuated regulator there are only a handful of sensing surfaces (float, diaphragm, piston, bellows, thermostatic cell) and biases (weight, spring). KSR: "if a technique has been used to improve one device, and a person of ordinary skill in the art would recognize that it would improve similar devices in the same way, using the technique is obvious."
• The travel-limiter motivation is express in the art. US471523A recites a stop "adapted to strike against a rod or flange I to limit the movement of the rod, so as to prevent damage to the valve or valve-seat." A POSITA seeking to keep the '582 head 5 from being driven beyond its seat by float over-travel — precisely the concern the '582 slot-and-pin couplings address — would adopt a limited-motion coupling. Slot-and-pin lost motion was itself a stock mechanical expedient for absorbing misalignment between non-coaxial moving parts.

Combination B: US857073A + US471523A + US394860A (or any ordinary radiator valve) + the boiler-float family (US155313A/US93021A/US86580A/US84444A/US64781A)

Same architecture, with the radiator-specific base (body/cap/neck/head, elements 1.1–1.4) taken from radiator hardware (US394860A "Air-valve for radiators," 1888, if its disclosure confirms a body-and-neck valve — unverified) and the float-and-lever regulator taken from the 1868–1874 boiler-regulator family. Motivation: all of these are float-actuated regulators in closed vessels where a float rides on and is displaced by a fluid, driving a valve through pinned levers to hold a condition constant; the transition from boiler feed/level regulation to radiator pressure/vent regulation is a change of use in the same art of automatically actuating a valve from a fluid-displaced body. The claim's floating "steam pipe," "float … movable with relation to said lower valve body portion," and lever/lug geometry add nothing structural beyond that art.

Combination C (hypothesis requiring verification): US937689A "Heating system" (1909) + a float-regulator + a weighted bias reference

US937689A is a steam-heating-system reference in the same field and within date; I could not verify its disclosure, so I present this only as a lead: if it shows a radiator-circuit valve automatically controlling steam admission/venting, it would strengthen the "field of endeavor" prong and could serve as the primary reference, with the float/lever art supplying the claimed structure.

Claim 2 — same combinations, plus

Claim 2's additional recitations are (i) "radial arms terminally carried by said stem," (ii) the float "fitted snugly and movably within the upper portion of the lower body portion," and (iii) the functional lost-motion clause "motion beyond a fixed limit being transmitted from said lugs to said arms." These are the clearest KSR-type "predictable variations" in the patent: (i) and (ii) are matters of obvious proportion/placement (MPEP 2144.04 — design choice/obvious rearrangement of parts), and (iii) is the express function US471523A's stop-nut arrangement performs. A challenge should note that (iii) is purely functional and, per In re Swinehart, covers the disclosed slot-and-pin structure and equivalents, which is broader than the specification.

VI. Where the claims might survive — and the § 112 problems that cut the other way

Best nonobviousness arguments for the patentee:

1. Specific slotted double-lever geometry (element 1.8). The particular arrangement — a lever pivoted at its longitudinal center on lugs depending from the cap, slotted at one end over a pin on a float lug (slot "l i"/14 over pin 15) and at the other over a pin on a radial wing of the valve stem (slot 9 over pin 8) — is a specific structure that none of the references I verified discloses. The patentee would also note that the float both raises and lowers the pivoted linkage, giving a compound mechanical advantage not shown in a simple bell-crank train.
2. The float as a pressure sensor inside a snug chamber rather than a level sensor. If the art of record (e.g., the boiler-regulator family) uses floats to sense liquid level, the patentee could argue the '582 float's function is different in kind. This is the strongest argument — but it collapses if the examiner shows any art (or the specification's own reasoning) treating the dome as a pressure-responsive piston, which the '582 specification effectively does, and which the '582's own G05D16/103 classification reflects.
3. No secondary-considerations record. The page contains no evidence of unexpected results, long-felt need, failure of others, or commercial success, so the Graham fourth factor is neutral-to-unfavorable; and there is no evidence of nexus to any such factor (In re GPAC Inc., 57 F.3d 1573 (Fed. Cir. 1995)).

Countervailing defects (which reduce the credibility of the claims as a nonobviousness bulwark):

• Claim 1's "fulcrumed within said float" is not supported by the specification ("fulcrumed upon lugs 22 carried by fingers 23 secured to the inner periphery of the lower body portion"), and claim 2 says "fulcrumed in said lower valve-body portion." A § 112 challenge to claim 1 is at least colorable, and, if sustained, leaves claim 2 (whose text is truncated in the available source) as the surviving scope.
• The "permitting limited relative movement" language is functional and indefinite as to structure absent the disclosed slots (In re Swinehart; MPEP 2111.01).

VII. Conclusion and confidence level

Bottom line. On the record available, the broad concept of claims 1 and 2 — a bias-loaded, fluid-displaced member (float) linked by pivoted levers to the head of a valve seated in the neck of a cap's valve body, so as to hold the steam pressure/temperature in a radiator below a set value — is highly likely obvious under pre-AIA § 103(a) over the combination of US857073A (valve + seat + stem + pressure-responsive piston in a chamber + bias + pivoted lever/link transmission in a heating system; verified), US471523A (lever/bell-crank motion transmission and an express travel-limiting stop to protect the valve and its seat; verified), and one of the listed float-regulator references — US435066A "Float-valve", US155313A, US93021A, US86580A, US84444A, or US64781A — for the float, its lugs, and the below-mounted weighted lever train. The motivation is supplied by the identity of field and problem (In re Bigio; KSR "design need"), by the finite set of known sensing surfaces and biases (MPEP 2144.03), and, for the lost-motion feature, by the prior art's own articulated purpose of preventing valve/seat damage.

Where my confidence is limited — and what must be done before filing any rejection:

1. I verified content for only two references (US857073A, US471523A). I could not verify the disclosures of US435066A, US394860A, US937689A, US155313A, US93021A, US86580A, US84444A, US64781A, US687002A, US50443A, US97485A, US86341A, US46142A, US62476A, or the remaining entries. A § 103 rejection cannot be written from Google's Similar Documents list; each reference must be read and, if its full text is not accessible, it must not be relied on for a missing element.
2. US1233937A must be excluded unless its filing date is shown to precede April 20, 1916 (pre-AIA § 102(e)).
3. The US394860A / Serial No. 394,860 collision must be resolved before any citation; and I could not retrieve that reference's text.
4. Claim 2 is truncated in the source ("…said last named lugs and 15"); the missing limitation must be obtained from the original grant before the claim can be fully evaluated.
5. The strongest residual nonobviousness position for the patentee is the specific slotted, centrally-pivoted angular-lever geometry of element 1.8 and the exact fulcrum/weight arrangement of element 1.10. Expect that to be the battleground; an examiner should search valve-gear and float-trap art for slot-and-pin lost-motion couplings between a float and a valve stem.

Practical note. Because the patent expired March 20, 1934, and its family (Google Family ID 3287458) contains only this single member, the realistic modern relevance of this analysis is the reverse direction — whether US 1219582, if asserted as a prior-art reference, is itself of unassailable validity — and, more pertinently, whether a later claim that relies on this disclosure for support can withstand a § 103 attack on the disclosure's own inventive contribution.