US 2008579

I'll search for this specific patent number across the requested sources.

Let me run additional targeted searches to verify and check for any litigation or CID records.

Report: US Patent 2,008,579 — "Screen"

1. Search hits and misses (what I could and could not confirm)

⚠️ Number-collision warning. A bare search for "2008579" returns EP 2008579 ("Process and apparatus for a wavelength tuned light source," The General Hospital Corporation, filed 2004-06-04, granted 2016-11-09, now lapsed — see pubchem.ncbi.nlm.nih.gov/patent/EP-2008579-A2 and the Irish/Belgian national registers). That is a completely different, unrelated patent in an unrelated field (optics/photonics). Per your instruction to interpret identifiers literally, I am confining this report strictly to US 2,008,579 / US2008579A, and flagging EP 2008579 only so it is not mistaken for the same document.

2. Bibliographic identification (US 2,008,579)

3. Abstract

Caveat: This patent issued in 1935, decades before abstracts became a formal requirement of US patent practice. There is therefore no patentee-authored abstract. The "Definitions" block on the Google Patents page is a machine-generated/auto-extracted summary, not the original disclosure. Two things follow: (a) any "abstract" given here is reconstructed, and (b) it should be labeled as such.

Reconstructed abstract (my synthesis, not the patentee's words): A suspended screen system for enclosing spaces such as hospital-bed cubicles, in which curtains hang from a trackwork of hollow metal tubing suspended in part from the ceiling and in part from a wall. The trackwork is assembled from a small number of standardized parts — straight tubular sections, short large-radius arcuate (curved) sections with adapter sleeves, and fittings (T, Y, and pronged fittings) that couple adjacent track sections while simultaneously suspending them from a common rod or tube. Because curtain hooks can pass freely through/over the suspension points, a single curtain can screen three sides of a space against a wall with no gap, and where cubicles are adjacent, a curtain on one track closes the third side of the neighboring cubicle — minimizing the amount of curtain material needed. The curtains terminate above the floor and below the ceiling for ventilation and sanitation, and all parts are preferably nickel- or chrome-plated.

4. Plain-language overview of the independent claims

All 18 claims are drafted in independent form (each begins "In a screen system, ..."). Grouped by theme:

A. Track geometry & overlapping/parallel tracks (the "no-gap" concept)

• Claim 1 — A system with a tubular track holding an arc-shaped fitting, plus a second tubular track ending near that fitting. A ceiling-hung support connects to both the arc fitting and the nearby track end, forming a continuous path so curtain hooks can run through.
• Claim 2 — A pair of tracks at least partly ceiling-suspended, one having an L-shaped section; one track ends in a short arc that is slightly spaced from, but runs alongside, part of the adjacent track. (This is the core anti-gap feature.)
• Claim 9 — A pair of generally L-shaped tracks spaced apart, with the free end of the base of one L positioned adjacent the angle (corner) of the next L. (Note: the OCR of this claim is truncated mid-sentence in the supplied text — I cannot verify its full scope from the available record.)
• Claim 10 — Multiple tracks where two have closely adjacent portions running in substantial parallelism, so their curtains hang side-by-side; plus overhead suspension.
• Claim 11 — Multiple separate tracks where one has an end portion running along a portion of the adjacent track, plus a common overhead suspension for both.
• Claim 15 — Multiple tracks where one has a curved portion and another runs alongside it in generally parallel relation.

B. The suspension fitting / bracket (tracks terminating near another track's middle)

• Claim 3 — Two adjacent tracks each with its own suspension bracket, each bracket being a fitting secured to the underside of its track and extending laterally and upwardly, with a receiver on the lateral portion for a vertical suspension member.
• Claim 4 — One track ends near the middle of another. A bracket is fixed to the underside of that intermediate portion, with a vertical part that interlocks with a fitting; the fitting has a lateral outlet receiving the terminal end of the adjacent track, and a vertical portion receiving a ceiling suspension member.
• Claim 12 — Similar to Claim 4: a terminal track end near an intermediate portion of an adjacent track; a fitting engages the terminal end and carries a bracket arm that engages the adjacent track; both are hung from the ceiling by common suspension means.
• Claim 16 — A pair of adjacent but separate tracks, each with a suspension bracket secured to the underside and extending laterally, plus a common overhead suspension supporting both brackets and tracks.
• Claim 17 — A ceiling suspension bracket with a part that extends under and interfits with an under-part of the track while leaving the track's top unobstructed; a securing member passes downward through the track into the bracket; suspension means attach to the bracket out of the track line (i.e., offset so hooks don't snag).

C. Wall/ceiling mounting bracket (plaster-preserving feature)

• Claim 5 — A wall or ceiling bracket with a flat plate; the plate is relieved (recessed) inwardly of its margin; the fastener hole passes through at that relieved area; and the bracket has a cup-like attachment member with the hole located inside the cup.
• Claim 6 — The disk-base version of Claim 5: a disk-like base with an open cup on one side; the wall-engaging side is relieved inward of the periphery; an aperture runs through and within the cup for the fastener; the cup is split to make it resilient; and a securing member draws the cup sides together to clamp.

(The stated purpose in the specification: by putting the screw far from the edge and engaging the wall only at the periphery, cracked or marred plaster is concealed under the base rather than spreading to the visible edge.)

D. Split-sleeve clamping fittings (the split-and-screw joint)

• Claim 7 — A support fitting with a sleeve-like opening to receive the track; the sleeve is split for resilience; a screw secures the track in the sleeve and draws the split parts together into a tight fit.
• Claim 13 — A fitting with a split sleeve-like receiving portion holding a suspension member; means to draw the parts together for a tight fit; plus means for supporting the track from the fitting.
• Claim 14 — A ceiling-dependent member and a fitting secured to it, with interfitting parts and means producing a radial clamping action between fitting and member.
• Claim 18 — The broadest version of this idea: track means plus a supporting fitting having a split, resilient sleeve-like receiving portion and means for contracting it.

E. Garbled claim

• Claim 8 — The OCR in the supplied text has run claim 8 into the tail of claim 7. The recoverable content describes a suspension bracket with a base, a laterally and upwardly extending arm with a supporting head shaped to the track surface, an aperture for a screw securing the track to the arm, and an upstanding lug that interfits with a part of a ceiling-suspended support. I am flagging this as uncertain — I cannot state Claim 8's exact boundaries from the available record.

5. CAFC 2026 docket check — explicit negative result

I found no CAFC 2026 docket, appeal, or order involving US 2,008,579. I want to be direct about two things:

1. This is the correct result, not a search failure. The patent's stated anticipated expiration is July 16, 1952. The Federal Circuit was not created until 1982 (Federal Courts Improvement Act of 1982). A patent that expired three decades before the court existed cannot be the subject of a 2026 CAFC appeal, an IPR, or a § 271 action. Indeed, the Google Patents "Cited By" list is only five items, the latest being a 2009 application, and none involve this patent as asserted subject matter.
2. Adjacent litigation I did locate (drapery/curtain hardware) involves H. L. Judd as a party but not this patent: Pleatmaster, Inc. v. J. L. Golding Mfg. Co. and H. L. Judd Co., 240 F.2d 894 (7th Cir. 1957), and H. L. Judd & Co. v. [Fowler] (1st Cir.). The very similar related patent referenced in the specification — the Vroom hook, US 1,857,293 (May 10, 1932) — is expressly disclaimed by Day as "not of my invention."

6. Uncertainty disclosures

• No patentee abstract exists for this 1935 patent; the Google "Definitions" text is auto-generated and is partly junk (see §3).
• The supplied full text is OCR-degraded. Reference numerals are rendered as letters throughout (e.g., "I3" for 13, "I5" for 15, "I9" for 19, "2!" for 21), and parts of the claim set (notably Claim 8, the tail of Claim 9, and the seam between Claims 9 and 10) are corrupted or truncated. My claim summaries above are reconstructions from that text and are reliable at the level of substance but not as verbatim quotations.
• Ownership lineage: Google lists the current assignee as H. L. Judd Co. Inc. / H. L. Judd Company Inc. I found a DOJ Antitrust Division competitive-impact statement and 1985 Federal Register materials describing Newell's 1981 acquisition of SDH, operated as "Judd Drapery Hardware." Whether that entity is the same corporate descendant of the 1931 assignee here is plausible but not confirmed by anything I retrieved. I would not state it as fact without the assignment record from USPTO Assignment Search.
• I did not have direct USPTO PatentCenter access; the bibliographic data above comes from the Google Patents record, which mirrors USPTO data but disclaims legal-status accuracy.

I'll search for litigation records involving US patent 2008579.

Let me run additional targeted searches to be thorough.

Let me run a few final verification searches.

Litigation Search: US Patent 2,008,579

Result: No litigation involving US Patent No. 2,008,579 was found.

I searched litigation-focused sources and general web/patent databases for the exact identifier 2,008,579 / US2008579. I found no district court case, CAFC appeal, ITC action, PTAB proceeding, or other adversarial proceeding in which this patent was asserted or challenged. Any case matching this number that turned up in searching was an unrelated matter in a different jurisdiction or numbering system (details below), and I did not count any of them.

Why this is the expected result

The patent's own record (Google Patents, fetched from https://patents.google.com/patent/US2008579/en) confirms:

Because the patent expired in 1952, any enforcement litigation would necessarily be ~75+ years old, pre-date modern docketing databases (PACER, Docket Navigator, Unified Patents portal, CourtListener's federal docket coverage for that era is essentially nonexistent), and would only appear — if at all — in old print reporters. Nothing for this patent number surfaced.

Unrelated hits that I did not count (same numeral, different subject)

Per the strict instruction to interpret identifiers literally and not auto-correct, these are distinct items, not the US patent:

• EP 2 008 579 – European patent, "Process and apparatus for a wavelength tuned light source," The General Hospital Corporation (Bouma et al.), filed 2004, granted 2016. Listed on the Austrian, Belgian, and Irish registers as lapsed/deemed void. This is an EP publication number, not the US patent.
• Brazilian STJ proceeding "RECURSO ESPECIAL Nº 2008579" – process 2022/0187279-1, Superior Tribunal de Justiça, distributed Aug. 31, 2022 (Relator Carlos Cini Marchionatti; Ministro Jorge Mussi, Quinta Turma). A Brazilian appellate docket number — no relation to the US patent.
• Tennessee state case no. 2008579 – East Memphis Neonatology v. Jacqueline McCorkle, Shelby County General Sessions, filed Aug. 14, 2019. A state collection-type case.
• Swedish SFS 2008:579 (Konkurrenslag / Competition Act) – a statute number cited in Swedish/Norwegian legal documents.
• Municipal file Nos. 4061-2008579/2023 – La Plata (Argentina) procurement records.

One adjacent historical item worth flagging (but it is not this patent)

Searching around the assignee/industry surfaced an old Ninth Circuit appeal brief (archive.org copy of gov.uscourts.ca9.05748) in which the H. L. Judd Company was funding the defense of a customer (LeSage & Company) and Judd employees William H. Edsall and Robert D. H. Vroom testified about a pin-hook patent dispute dating to the 1880s–1920s, and about Judd's consideration of "McGhee & Jinks" hooks and U.S. Patent No. 1,334,661. This case involves hook patents and predates the '579 patent entirely; the '579 patent number does not appear in it. I am not asserting it as litigation over US 2,008,579 — only noting it because it involves the same assignee (Judd) and the same product family (hospital/curtain hardware) and could otherwise be mistaken for a hit.

Separately, the '579 specification expressly disclaims ownership of the curtain hook shown in Figs. 3–4, identifying it as the subject of U.S. Patent No. 1,857,293 (Robert D. W. Vroom, May 10, 1932). That is a different patent; its litigation history, if any, is likewise not litigation over the '579 patent.

Caveats on completeness

• I could not run a full PACER or Docket Navigator query in this session, and the Unified Patents litigation portal (https://portal.unifiedpatents.com/litigation/caselist) returned no matching entry in the search results I retrieved. My conclusion rests on those search results, not on a subscription-database query.
• Given the patent expired in 1952 and predates electronic docketing, I would treat "no litigation found" as "no litigation found in the sources searched" rather than an absolute negative. If you need a definitive negative, the appropriate step is a manual Westlaw KeyCite / Lexis CourtLink history check on U.S. Patent 2,008,579 and a review of old print reporters (e.g., the Federal Reporter volumes covering 1935–1952), which is exactly the methodology the USPTO's own Central Reexamination Unit litigation search reports use.

Bottom line: No known litigation involves US Patent No. 2,008,579. All matches for the numeral "2008579" that surfaced are unrelated foreign patents, foreign/state docket numbers, or statutes.

I'll verify the absence of PTAB activity with a couple of targeted searches before writing up.

Proceedings overview

Total AIA trial proceedings on file: 0 — zero active, zero with claims invalidated, zero with claims sustained, zero settled, zero institution denials. US 2,008,579 ("Screen," Courtenay P. Day, assignor to H. L. Judd Company, Inc.) has never been the subject of an IPR, PGR, or CBM review, and the defensive posture this gives a defendant is not "hardened patent" but rather the opposite: the patent expired on 1952-07-16 and is nine decades past its term, so there is no valid infringement theory to defend against in the first place — any demand letter citing "US 2008579" or "US 2,008,579" is baseless on its face.

Supporting record:

Source of record: https://patents.google.com/patent/US2008579/en · PTAB E2E: https://ptacts.uspto.gov/ptabweb · CourtListener: https://www.courtlistener.com/

Per-proceeding detail

There are no proceedings to detail. No ### {PROCEEDING_NUMBER} — {Petitioner} v. {Patent Owner} entries can be generated, because no proceeding number exists. I have not invented petition numbers, panels, or dispositions, and the required fields (judge panel, institution decision, FWD claim-level verdict, settlement, appeal docket) are all empty by fact, not by omission.

Why the list is empty (and why that is a legal, not a records, conclusion)

1. PGR is unavailable by statute. Post-grant review under 35 U.S.C. §§ 321–329 reaches only patents with an effective filing date on or after 2013-03-16 (AIA § 3(n)(1)). This patent's effective filing date is 1931-01-06.
2. CBM is unavailable by subject matter and by sunset. AIA § 18 limited CBM review to "covered business method" patents — claims for performing data processing or other operations used in the practice, administration, or management of a financial product or service. This is a hospital-bed curtain-track patent. The CBM program also sunset for new petitions on 2018-09-16.
3. IPR is technically available for pre-AIA patents, but practically foreclosed here. IPR under §§ 311–319 carries no filing-date limit, but § 315(a)(1) and § 315(b) require the petitioner to have been sued for infringement (or to file within one year of service of a complaint). With the patent expired since 1952-07-16, no live infringement action can be brought — 35 U.S.C. § 286 caps damages at six years pre-suit, and the term itself ended 74 years ago. No accused infringer exists, so no statutory petitioner exists.
4. The patent's own prosecution is the entire public validity record. The only substantive examination was the 1931–1935 prosecution; the specification even notes that the curtain-hook detail is not the invention but is claimed in Vroom patent No. 1,857,293 (issued 1932-05-10). No ex parte reexamination, no reissue, no PTAB trial, and no Federal Circuit appeal of this patent is on file.

Strategic summary

Claim status across AIA proceedings: all 18 claims are UNTESTED — none CANCELED, none SUSTAINED. Claims 1 through 18 (including the independent track/suspension claims 1, 2, 3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18) have never been construed or adjudicated in a post-issuance proceeding. That framing matters, because "untested" here does not mean "vulnerable but unexplored" in the usual sense — it means no forum has jurisdiction over a live controversy about them, because the exclusive right granted in 1935 lapsed in 1952. There is no surviving claim set to narrow, and no reissue or certificate of correction of record that could revive anything.

Estoppel landscape: none, because there is no petitioner. 35 U.S.C. § 315(e)(2) estops a petitioner (and its privies) from raising in a civil action any ground raised or reasonably could have been raised in an IPR that reached a final written decision. With no IPR instituted and no FWD, no party is estopped by anything. That cuts the other way for a defendant, however: the doctrine you would normally use to keep the patent owner's infringer-art out of litigation is irrelevant when there is no litigation to defend. Any prior-art ground a defendant cares to raise (including the 1930s curtain-track art, forward-cited documents such as US2706306, or the Vroom '293 hook patent) is fully available and was never presented to the Office — but the stronger point is the expiry date, which disposes of the matter before validity is ever reached.

Pattern signals: none of the classic hallmarks are present. No repeat petitioner, no Unified Patents or other defensive aggregator in the chain, no PTAB appeal activity, no joinder. The patent's only measurable "activity" is downstream citation: five later documents cite it (US2589878 (1952), US2639041 (1953), US2706306 (1955), US20070261803A1 (2007), US20110203629A1 (2011)), plus a 1932 court/board-era cross-reference to Vroom '293. Those are forward citations evidencing the art's influence on hospital-curtain hardware, not evidence of assertion. As a portfolio matter, H. L. Judd Company's 1935 asset has been dead IP for three quarters of a century; the absence of PTAB activity is not a "troll hasn't been hit yet" signal — it is the predictable signature of a patent with no remaining term.

Recommended next steps

• If you received a demand letter citing US 2,008,579 (or "US2008579" / "2008579"): do not negotiate on validity or infringement. Confirm the front page: "Patented July 16, 1935" and "Anticipated expiration 1952-07-16" (https://patents.google.com/patent/US2008579/en). A pre-1995 patent had a 17-year term from grant, which ran out on 1952-07-16. There is no enforceable right to license, and no § 271 infringement is possible. Preserve the letter; an assertion of an expired patent can support fee-shifting under 35 U.S.C. § 285 (if in litigation), Rule 11 exposure, and state-law unfair-competition / deceptive-practice claims.
• There is no FWD, IPR certificate, or CAFC opinion to link or quote. The disposition you would ordinarily cite — "claims X–Y held unpatentable" — does not exist, and I will not manufacture one. The dispositive citation is the patent document itself, not a PTAB paper. PTAB E2E party/patent search (https://ptacts.uspto.gov/ptabweb) returns nothing for this patent, consistent with the ODP structured block.
• No trial-stage milestones to calendar. There is no institution-decision deadline, no oral hearing, and no statutory one-year FWD deadline running, because no petition is pending. The AIA § 6(c) one-year clock from institution never started.
• Plain statement of the negative finding: there is no PTAB activity on US 2,008,579. Ordinarily the absence of IPRs is itself a signal that a patent is either quietly settled or not worth asserting. Here the explanation is simpler and stronger — the patent expired 1952-07-16, and IPR/PGR/CBM review of it is foreclosed as a practical matter (no statutory petitioner under § 315(b)) and, for PGR and CBM, by statute outright.
• Caveat on scope of this search: this conclusion rests on the USPTO ODP structured list (canonical) plus targeted web searches on 2026-09-26, which surfaced no petition, FWD, or appeal for this patent number. I did not locate any older or recently-filed proceedings that the ODP has failed to index. If you are relying on this for litigation, commission a PTAB E2E "Patent Number" search and a CourtListener docket check under both "2,008,579" and the 1931–1952-era assignee variants (H. L. Judd Company, Inc.) before certifying the negative to a court.

I'll attempt to retrieve assignment records for this patent and context on the assignee chain.

Good context on the assignee. Let me probe the assignment record and the corporate succession.

Let me pin down the inventor's role and check for any indexed assignment/legal-event records.

Data-retrieval caveat (read first)

I was unable to execute a live query against USPTO Assignment Center in this session. My tool calls were capped before I could retrieve assignmentcenter.uspto.gov results, and none of the searches I did complete returned an Assignment Center entry (reel/frame, assignor, assignee, correspondent) for US 2,008,579. The Google Patents record I was given as the authoritative source (https://patents.google.com/patent/US2008579/en) lists no post-issuance legal events other than priority, grant, publication and anticipated expiration — no "Assigned to" events appear in its Legal Events table.

So the finding below is "no recorded assignment found in the sources retrieved," not an absolute negative. Treat every reel/frame reference as unavailable, and specifically do not accept any invented reel/frame from a downstream re-run of this prompt.

One flag against the prior sections: Google Patents displays both "H L JUDD Co Inc" and "H L JUDD COMPANY Inc" under Current Assignee. That is not evidence of a post-issuance transfer or a name-change recording. Both strings are the same Delaware corporation named on the face of the patent; the duplicate is a data-variant artifact of the Google Patents assignee normalizer. Do not count it as a link in the chain.

Inventors

Sole inventor: Courtenay P. Day, of New York, N.Y. (per the printed front page of US 2,008,579).

• Employer at filing: H. L. Judd Company, Inc. This is determinable, not inferred from naming: the patent's own front page reads "assignor to H. L. Judd Company, Inc., New York, N.Y., a corporation of Delaware," i.e., Day assigned the application to Judd at or before the 1931-01-06 filing date. An in-application assignment of this kind is the standard signature of an employee invention.
• Possible family/management tie (unresolved): Testimony in the H. L. Judd-related Ninth Circuit brief (gov.uscourts.ca9.05748, archive.org) refers to John Day as president of H. L. Judd Company, signing a 1914 royalty contract for the Ashmore pin, and identifies William H. Edsall and Robert D. H. Vroom as Judd officers/inventors. Whether Courtenay P. Day is related to John Day is not established by anything I retrieved — I am flagging it as an open question, not a finding.
• Departure pattern: Not determinable. There is no evidence Day left Judd, and no evidence he stayed. Note that the same-era Judd inventors stayed: Vroom retired from Judd in 1954 after 67 years with the company (NYT obituary, 1955-11-27), and Edsall was a Judd vice-president in the 1920s. The "all inventors departed within 12 months → portfolio fire-sale" pattern is not present on the record available.
• Prosecution oddity worth noting (not an assignment): the patent is stamped "Renewed January 20, 1933" — a two-year gap between the 1931-01-06 filing and the renewal, with grant on 1935-07-16. That is a ~4.5-year pendency handled under then-current renewal practice. It is a prosecution fact, not a conveyance, and should not be counted as an assignment link.

Original assignee

H. L. Judd Company, Inc. — named on the issued patent, corporation of Delaware, with its business address given as New York, N.Y.

• Primary line of business: manufacturer of upholstery hardware, drapery hardware, curtain poles, shade and carpet hardware, and wire goods. Corporate lineage (per Connecticut local histories and the RootsWeb New Haven County biographies): H. L. Judd & Company established 1874 in Brooklyn by Edward Morton Judd (whose 1856 metal curtain fixtures were an early US metal curtain-fixture business); incorporated 1884; acquired the Judd Manufacturing Company of Wallingford, Conn. in 1886; Brooklyn plant discontinued 1897; factories at Wallingford, Conn. and Chattanooga, Tenn. (the Chattanooga plant was a curtain-pole factory).
• Did it ship a product embodying the claims? Yes, on the record. The '579 claims are directed to trackwork and mounting hardware — tubular track, arcuate sections, split-sleeve fittings, ceiling/wall brackets, common suspension brackets (claims 1–8, 12–18) — and the specification states the system "is admirably adapted for hospital use, where it has met with considerable success." Judd was an operating curtain/drapery-hardware manufacturer with published catalogues (e.g., Catalogue of upholstery hardware: curtain poles, shade and carpet hardware, Catalogue No. 42, October 1, 1904, held by Winterthur) and 1940s trade advertising (e.g., "Judd Corner-Mitre Cornice," Industrial Design-era trade press). Judd also practiced what it patented: the specification expressly disclaims the Figs. 3–4 curtain hook, identifying it as the subject of US 1,857,293 (Robert D. W. Vroom, May 10, 1932) — a Judd house patent by a Judd vice-president. This is a classic operating-company, in-house-inventor portfolio.
• Enforcement posture while operating: Judd was an assertive/defensive participant in patent disputes in the 1920s–30s. In the Ninth Circuit brief, Judd was funding the defense of its customer LeSage & Company in a drapery/pin-hook patent case, with Judd employees Edsall and Vroom testifying; the brief also recounts Judd's 1914 exclusive-manufacturing royalty contract with Edith Bancroft Ashmore for the "Ashmore pin." This is operating-company assertion, not NPE behavior.
• Current status: Dissolved by absorption. In 1954 The Stanley Works of New Britain, Connecticut purchased H. L. Judd and Company, absorbing its manufacturing operations and approximately 600 workers, and renamed it Stanley-Judd Company. Stanley-Judd drapery products "remained strong through the 1970s" and "operations were shut down shortly thereafter"; the Wallingford factory was redeveloped in 1989 as Judd Square Condominiums (Connecticut Mills / connecticutmills.org, "H.L. Judd Co."). Corporate successor chain runs to Stanley Black & Decker. Critically, this patent had already expired on 1935-07-16 + 17 years = 1952-07-16, two years before the Stanley purchase — so the 1954 acquisition cannot have conveyed any live rights in the '579 patent.

Assignment timeline

Finding: USPTO Assignment Center returned no recorded assignment entries for US 2,008,579 in the sources I was able to retrieve, and Google Patents' Legal Events for this patent show none. There are therefore no reel/frame numbers to report, and I will not invent any. Per the instruction to say so plainly: this patent has no recorded post-issuance assignment that I could locate. The only conveyance is the pre-issuance assignment printed on the face of the patent, which is not a reel/frame recording (patent assignments of that era were recorded in Liber/Page books, not in the reel/frame image series, which begins in the mid-1950s):

• Executed on or before 1931-01-06 (filing date) / recorded — reel/frame: not available
  • Conveyance: Assignment (of the application, recited in the patent's front-page assignee clause: "assignor to H. L. Judd Company, Inc.")
  • Assignor: Courtenay P. Day
  • Assignee: H. L. Judd Company, Inc., New York, N.Y., a corporation of Delaware
  • Correspondent: Not determinable. The patent front page names no prosecuting attorney, and no assignment record was retrievable to expose a correspondent of record. I am not naming anyone.
  • Context: employment/invention assignment to the operating manufacturer — the normal in-house pattern, not a fire-sale or securitization.

For completeness, the one corporate event that could plausibly have carried this patent's (by-then-expired) rights, and which is not an Assignment Center recording:

• 1954 — The Stanley Works acquired H. L. Judd and Company, renamed it Stanley-Judd Company. Not a recorded assignment against US 2,008,579; a stock/asset acquisition of the operating company, occurring two years after this patent expired (1952-07-16). Patent rights in an expired patent are not an enforceable asset, so this event carries no NPE significance for the '579 patent.

Implication of the null result: with no post-issuance assignment and no corporate successor asserting the patent, the reasonable reading is that this patent died owned by its original assignee, H. L. Judd Company, Inc. (absorbed into Stanley Works in 1954, patent already expired).

Timeline diagram

timeline
    title Ownership of US 2008579
    1874 : H L Judd and Company founded in Brooklyn
    1884 : Judd incorporated in New York
    1886 : Buys Judd Manufacturing of Wallingford
    1931 : Application filed by Courtenay P Day
         : Rights assigned to H L Judd Company Inc
    1933 : Application renewed
    1935 : Patent US 2008579 granted to Judd
    1952 : Patent term expires
    1954 : Stanley Works absorbs H L Judd and Company
    1989 : Wallingford Judd plant redeveloped

NPE / troll-pattern signals

Because there are no recorded assignments at all, most of these signals are answerable only as "no evidence," which is materially different from "affirmatively absent." I have marked each accordingly.

1. Shell-entity transfer — Not present. No assignee with an "IP / Patents / Licensing / Holdings / Ventures" suffix appears anywhere in the record. The sole assignee is H. L. Judd Company, Inc., an operating manufacturer with factories in Wallingford, Conn. and Chattanooga, Tenn. and a published product catalogue (1904, and continuing into the 1940s). No single-purpose LLC, no registered-agent address, no Delaware/Texas licensing shell.

2. Known asserter in the chain — Not present. No match against the enumerated list (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities). The only entity in the chain is Judd, and Judd's own litigation history (funding its customer's defense in the Ninth Circuit pin-hook case; its 1914 Ashmore exclusive-manufacturing royalty deal) is operating-company patent activity, not NPE activity. No RPX or Unified Patents asserter-directory hit surfaced.

3. Repeat correspondent across the chain — Not present / not determinable. Zero retrievable corresponding-attorney entries, so there is no recurrence to measure. I am explicitly not treating the absence as exculpatory evidence — there is simply no correspondent data.

4. Cascading transfers — Not present. A single owner from 1931 filing to 1952 expiry is the opposite of the chained-LLC pattern (<24-month hops, shared correspondent address, common principals).

5. Pre-litigation transfer — Not present. No infringement suit naming this patent was found (see the prior litigation section), so there is no litigation date to measure a 6-month window against. The patent expired 1952-07-16, which caps the entire universe of possible assertion dates.

6. Bankruptcy fire-sale — Not present. No Chapter 7/11 of the assignee surfaced. The 1954 event is a solvent operating-company acquisition by The Stanley Works (~600 employees absorbed, factory continued producing under the Stanley-Judd name), not a distressed patent auction. Separately, it post-dates expiry by two years.

7. Privateering — Not present. No operating-company-to-NPE transfer, no SEC-disclosed patent-transfer-to-asserter arrangement, no Patent Progress/EFF coverage surfaced. Judd kept and practiced its own patents (cf. its house patent US 1,857,293 to Vroom and US 1,604,937 to Edsall).

8. Defensive aggregator — Not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. (This signal would have been an interesting inverse finding — neutralization — but it is simply not what happened.)

Verdict

Insufficient data — per the rubric's own definition ("no records, or only the original assignment"). The assignment record for US 2,008,579 reduces to the single face-of-patent assignment from Courtenay P. Day to H. L. Judd Company, Inc. at filing on 1931-01-06; no post-issuance assignment exists in Google Patents' Legal Events table, and my searches for an Assignment Center entry returned nothing, so no reel/frame, correspondent, or conveyance-type data is available to report.

That said, the substantive ownership picture is not actually murky, and it is worth stating plainly even though the rubric forces the "insufficient data" label: the patent was owned throughout its life by an operating curtain-and-upholstery-hardware manufacturer with factories in Connecticut and Tennessee that shipped products embodying the claims; it expired 1952-07-16; and its owner was absorbed by The Stanley Works in 1954, two years after expiry. No NPE signal is present on any evidence I retrieved, but with no reel/frame records available I will not upgrade that to "affirmatively exonerated," and the absence of a correspondent field means signal 3 is unassessable rather than negative.

Verification links (please re-run these directly, since I could not complete them here):

• Assignment Center search page: https://assignmentcenter.uspto.gov/
• Legacy indexed search: https://assignment.uspto.gov/patent/index.html
• Authoritative patent text/legal events: https://patents.google.com/patent/US2008579/en

Recommended next steps for a definitive record: (1) query Patent Assignment Search by patent number 2,008,579 and by assignor name "Judd" restricted to 1931–1954, checking the Liber/Page books that pre-date the reel/frame series; (2) pull the original application file wrapper for Serial No. 506,870 (including the 1933-01-20 renewal) to capture the recorded assignment document and any named correspondent; (3) confirm whether any Judd patent assets were itemized in the 1954 Stanley Works acquisition — though note that, by then, the '579 patent had no remaining term to convey.

I'll research this systematically — first confirming the '579 record, then hunting cited/related prior art for each claim.

The generic searches keep hitting EP 2008579 (a different, unrelated EP patent). Let me target the US patent's own citation record directly.

The cited references aren't appearing in the fetched record. Let me pull the patent's front page directly from alternative databases.

Prior-Art Analysis: US Patent 2,008,579 ("Screen")

1. Verification of the Target Document

Retrieved from https://patents.google.com/patent/[US2008579](/patent/US2008579)/en (the authoritative text supplied to me):

I kept this identifier literal and did not auto-correct it. As detailed in the earlier litigation section, the untouched numeral "2008579" also matches EP 2 008 579 (General Hospital Corp., wavelength-tuned light source), an Austrian/Belgian/Irish register entry — that is a different instrument and is excluded here.

2. The Critical Finding: The '579 Record Contains No Backward Citations

This is the single most important result of the search, and it changes how the rest of the question must be answered.

The record as retrieved contains no "Patent Citations" / "References Cited" block at all. The Google Patents HTML for US2008579A as fetched has:

• a Classifications block,
• a Definitions block (auto-generated and visibly OCR/noise-garbled — e.g. "Varicus," "sage," "7," "cubicles;" — not claim text and not to be relied on),
• "Cited By (5)" — i.e., forward citations (documents that cite '579),
• a "Similar Documents" block (algorithmic similarity, not examiner citations),
• and nothing else.

So, taken literally: there are zero examiner-cited or applicant-cited prior-art references on the face of US 2,008,579 as retrieved. The "patent citations for 2008579" that a reader would expect to analyze do not exist in this record.

Two honest possibilities, which I cannot distinguish from the material available to me (I hit my search-step limit before reaching the printed front page, FPO, or patentimages):

1. The 1935 printed patent genuinely listed few or no references (plausible for a narrow mechanical art — note the equally tiny forward-citation count of 5); or
2. The citation block exists on the printed front page but was not extracted into the HTML/OCR I was given.

Recommended verification step: pull the printed front page from USPTO Patent Public Search / Patent Center for 2,008,579, or the patentimages PDF, which is where the "References Cited" list, examiner name, and any "Renewed" annotations actually live.

3. The One Reference Named Inside the Specification

There is exactly one patent identifier mentioned in the '579 disclosure itself:

"The specific hook shown in Figs. 3 and 4 is illustrated merely as a hook adaptable to my screen system. The details of that hook are not of my invention, but are described and claimed in the patent of Robert D. W. Vroom, No. 1,857,293, May 10, 1932."

• US 1,857,293 A — "Curtain hook," Robert D. W. Vroom, H. L. Judd Company Inc.; filed Jan. 9, 1931 (Appl. 507,598); granted May 10, 1932. (https://patents.google.com/patent/[US1857293A](/patent/US1857293A)/en ; https://www.freepatentsonline.com/1857293.html)
• § 102 status against '579: not prior art on these facts. Its grant date (May 10, 1932) is after the '579 filing date (Jan. 6, 1931), and the '579 specification expressly disclaims it as the invention ("not of my invention"). It is a co-pending, commonly-owned companion patent, cited as attribution, not as anticipation. It could theoretically function as § 102(e) art (US patent granted on an application filed before the '579 invention date) only if the same inventive entity — it is not; different inventor — and only for what it enables. Note the '579's Fig. 3–4 subject matter is therefore outside claims 1–18 except insofar as a claim recites curtain hooks generically (claims 1, 4 recite "curtain hooks," but as functional environment, not structure).

4. The Five "Cited By" Documents — Legally Impossible to Anticipate '579

The user asked for § 102 mapping for each citation. For these five, the analysis is dispositive and short: all post-date the '579 filing, so none can be § 102(a)/(b)/(e)/(g) prior art. They are presented here because they are the only "citations" in the record, and because they show what the later art regarded '579 as teaching.

Which claims do they "potentially anticipate"? None — anticipation requires the reference to predate the invention/filing. At most they are § 103-adjacent "secondary evidence" of what the field later treated as routine (e.g., Sheetz's plural-track hanger suggests the '579 common-suspension-for-plural-tracks concept — claims 3, 10, 11, 16 — was unremarkable by 1954). That is a scope observation, not an anticipation mapping.

5. The Only Pre-1931 Documents in the Record: Google's "Similar Documents"

Google's Similar Documents list is algorithmic, not a citation list, and — I want to be blunt about this — its relevance signal is poor here: it includes a quilting-frame, a table-and-chairs combination, a disappearing bed, and a ventilator. I have not read the disclosures of these references in this session, so everything below is a candidate screen, keyed to title/subject/date, flagged as reachability: Low / Moderate. Under § 102 each would need to disclose all elements of a given claim in one reference; on titles alone, none can be shown to do so.

5a. Candidates that are § 102(b)-eligible (published > 1 year before Jan. 6, 1931)

All eight issue more than one year before the Jan. 6, 1931 filing → § 102(b) eligible on their face. The best three to actually pull and read are US 1,520,265, US 1,475,576, and US 1,524,724.

5b. Additional Judd-family art surfaced by my own searching (not in the record, but highly probative)

These I did retrieve with URLs, and they matter more than most of the list above:

6. Claim-by-Claim § 102 Screen (What to Attack, and With What)

The 18 claims fall into three structurally distinct groups. § 102 analysis should proceed group-wise:

Note on claim 6's "plaster-saving" limitation — the '579 specification argues a specific technical effect: "the securing screw 39 being so far removed from the edge, any cracks or marring of the plaster by such screw will not extend out as far as the edge." That is a result argument. For § 103, a bracket with a central fastener and relieved perimeter is a mechanical expedient; look for the closest bracket art in group C before conceding validity.

7. Contradictions / Flags Against the Earlier-Generated Section

• No contradiction found. The litigation section's stated dates (filed 1931-01-06; granted 1935-07-16; expired 1952-07-16; 5 forward citations) match the patent record verbatim.
• One correction of emphasis to carry forward: the litigation section correctly noted that the CA9 brief involving Judd (gov.uscourts.ca9.05748) is about hook patents (McGhee U.S. 1,334,661; Tonks/Whitehouse catalogues) and is not litigation over '579. My research reinforces this: that material is § 102 documentary/prior-publication evidence for a different patent family, and should not be folded into a '579 prior-art chart except to show Judd's practice and catalogue prior art in the same trade.
• Do not treat the "Definitions" block in the fetched record as claims. It is garbled extraction text (e.g., "Varicus," "sage," "cubicles").

8. Bottom Line

1. US 2,008,579's record, as retrieved, cites no prior art. There is no "References Cited" block — only 5 forward citations and an algorithmic "Similar Documents" list. If the task requires "the patent citations for 2008579," the honest answer is that this record contains none, and the printed front page should be pulled from USPTO to confirm or refute that.
2. The only patent named in the specification is US 1,857,293 (Vroom, 1932), expressly disclaimed as the invention and post-dating the '579 filing — not § 102 prior art against '579.
3. All five "Cited By" documents post-date '579 by 17–79 years — none can anticipate any of claims 1–18 under 35 U.S.C. § 102(a), (b), (e) or (g).
4. The only anticipation-eligible documents in this record are the 8 pre-1931 items in Google's "Similar Documents" list (US 757,175; 931,962; 983,957; 1,475,576; 1,493,119; 1,520,265; 1,524,724; 1,711,070). The three most worth reading are US 1,520,265, US 1,475,576, and US 1,524,724, aimed at claim group B, and US 1,711,070 for claim group A.
5. The single strongest external prior-art candidate I located is US 1,055,925 (Lathrop, H. L. Judd, granted 1913-03-11) — same assignee, same product family, split-resilient-socket concept — but its structure is inverted relative to '579's split coupling, so it is § 103 material, not a clean § 102 anticipation of claims 7/13/18.
6. Caveats I am not hiding: I did not read the disclosures of the "Similar Documents" references; I could not complete the query against USPTO Patent Center, FPO, or the patentimages front page before exhausting my search steps; and my § 102 designations rest on publication dates and titles. Every "reachability" rating above is a screening estimate, not a finding of anticipation.

I'll pull details on the prior-art candidates listed on the patent page before doing the §103 analysis.

Let me pull the remaining pre-1931 references from the "Similar Documents" list.

Obviousness Analysis — US 2,008,579 ("Screen"), 35 U.S.C. § 103

Building on prior sections. This section assumes the bibliographic findings, claim breakdown, and the "no litigation found" conclusion already given. It does not re-derive them. Two cross-references are load-bearing here and are restated only as needed: (i) the effective filing date is January 6, 1931 (App. No. 506,870), with the printed patent also reciting "Renewed January 20, 1933"; and (ii) the "Cited By" and "Similar Documents" lists on the Google Patents page are not the same thing as an examiner's citation list.

1. Threshold issue: what on this page is actually available as § 103 prior art

Critical methodological finding. The fetched page for US2008579 contains no backward "Patent Citations / References Cited" section. It contains only:

• "Cited By (5)" — forward citations (later documents citing '579), and
• "Similar Documents" — a machine-similarity list, not an examiner citation list. It is generated from classification/text overlap and contains documents from after the patent issued, as well as art in merely-adjacent fields.

This matters enormously. A § 103 rejection cannot be built on forward citations or on a similarity list. Each candidate must independently satisfy § 102(a)/(b)/(e) as of the critical date and be analogous art.

1.1 The "Cited By" five — all legally unusable as prior art

These can be used only as (a) evidence of the ordinary level of skill / what a PHOSITA would find predictable, or (b) evidence of the field's trajectory. They are not § 102 art. Note in particular that US2706306 ("Hanging bracket for plural tracks," 1954) is a later patent to a bracket supporting plural curtain tracks — i.e., by 1954 the very concept of a common bracket for multiple tracks had become routine enough to be claimed again. That cuts against non-obviousness of claims 3, 4, 12, 16.

1.2 "Similar Documents" — split by date

Everything else in the Similar Documents list is post-1931 and cannot be prior art: US2103642 (1937), US2107421 (1938), US2144753 (1939), US2175501 (1939), US2223282 (1940), US2240406 (1941), US2374165 (1945), US2459503 (1949), GB467567 (1937), US2650715 (1953), US2837307 (1958), US2903765 (1959), GB1346375 (1974), CN107374108B (2019).

Robustness to the renewal wrinkle. The printed patent recites renewal on January 20, 1933. I am not certain, and cannot state with high confidence, whether pre-1952 renewal practice could shift the § 102(b) critical date from January 6, 1930 to January 20, 1932. The analysis is insensitive to that question: the latest qualifying reference (US1711070, 1929-04-30) predates both candidate critical dates by more than a year. All eight documents above are § 102(b) art under either view. (Flagged as uncertain; verify against the assignment/renewal record if this ever needs to be briefed.)

1.3 Additional prior art usable here: the applicant's own admissions

The specification's background is an admission of the state of the art and is directly usable in a § 103 analysis:

• Cubicle screening had conventionally used "floor screens, which are supported by stands from the floor" or "suspended sliding curtains so arranged that three separate curtains are required."
• In such systems "it has been impossible to secure complete screening, for the reason that the curtains do not properly overlap, and the slightest breeze would cause the curtains to blow open and expose the interior of the screened space."

This is a self-identified, admitted problem — the strongest single motivation statement available against the "no-gap" claim family (§§ 1–2, 9–12, 15).

1.4 Reference the specification cites but disclaims

The hook of Figs. 3–4 is expressly disclaimed: "The details of that hook are not of my invention, but are described and claimed in the patent of Robert D. W. Vroom, No. 1,857,293, May 10, 1932." That patent issued after the 1931 filing date, so it is available as § 102 art only via § 102(e), and only if its application was filed before Day's invention date. In any event no claim of '579 recites hook structure, so the Vroom patent is irrelevant to every claim at issue. It is worth noting only because a careless searcher will treat the '579 drawing as disclosing the Vroom hook.

2. Level of ordinary skill in the art (Graham factor 1)

A PHOSITA as of January 1931 would be a mechanical designer or installation mechanic with roughly 2–5 years' experience in drapery/curtain hardware or hospital-equipment installation, holding at most a high-school or trade-school mechanical education. That person's knowledge base would include:

• tubular rod/track stock and the practice of cutting stock to length on site;
• sliding hangers/rollers running on a suspended track (including the Vroom-type roller hook and the older drapery pin-hook family);
• curved or corner-turning curtain rods (see the A47H2001/0205 "curved curtain rods" classification the patent itself carries);
• screw-and-slot adjustable brackets attached to window casings and walls (US1524724, US1475576, US1520265);
• split-collar / clamping-sleeve fastenings in general mechanical use;
• the practical problem of spalling plaster when screwing fittings into lath-and-plaster.

3. Graham/KSR framework applied

Governing rationales available under KSR: (1) combining prior-art elements according to known methods to yield predictable results; (2) simple substitution of one known element for another; (3) use of a known technique to improve a similar device in the same way; (4) applying a known technique to a known device ready for improvement to yield a predictable result; (5) "obvious to try" in a field of a finite number of identified, predictable solutions; (6) design incentives / market forces; (7) enablement of a design need or market pressure that produces a finite number of predictable variations.

4. Claim-by-claim combinations and motivations

4.1 Group A — Inter-track geometry (claims 1, 2, 9, 10, 11, 15)

Candid weakness of this grouping. On the page's face, no listed pre-1931 reference discloses two curtain tracks arranged with one terminating alongside the other's intermediate portion and a common suspension. The closest pre-1931 disclosures I could verify are lateral/parallel fittings (US1524724's slotted strips and angle clips) and canopy/drapery frames (US757175), neither of which is a suspended two-track curtain rail. A rejection on claims 1, 2, 10, 11 and 15 would therefore have to rest heavily on the applicant's own admission of the gap problem plus a KSR "finite number of predictable solutions / obvious to try" rationale, rather than on a clean element-by-element reference mapping. That is a defensible but not a strong prima facie case. Claims 9 and 12 (see below) are weaker for the patentee; claims 2 and 11 are stronger.

4.2 Group B — Suspension brackets (claims 3, 4, 12, 16, 17)

4.3 Group C — Wall/ceiling bracket (claims 5, 6)

Candid assessment of Group C. This is the patentee's best defensive ground. The relief geometry — a base engaging the wall only at its periphery while the screw sits centrally and the material in between is relieved — is a genuinely specific structural insight about how plaster spalls, and I have not verified any pre-1931 reference on the page (or elsewhere) that discloses it. A PHOSITA in 1931 might well have used a cover plate, but the relieved underside with peripheral-only engagement is a narrower thing. Claims 5 and 6 have the best survival prospects.

4.4 Group D — Split-sleeve clamping fittings (claims 7, 13, 14, 18)

Candid weakness of this grouping. The page's pre-1931 list does not include a verified reference disclosing a split sleeve with a contracting screw. My searches did not return the contents of US1520265, US1475576, or US1493119 (the tool-call budget was exhausted before those could be pulled). A rejection on Group D therefore currently rests on general mechanical knowledge and the split-collar expedient's notoriety, which is a legitimate but evidentiary-dependent route: the examiner would need either a specific reference or a judicial-notice-type showing. Flag: verify. Subclass A47H and the analogous clamp subclasses are where that reference will be found.

4.5 Claim 8

Claim 8 is garbled in the supplied text (the OCR runs it into the tail of claim 7) — the same defect already flagged in the claim-summary section. Recoverable content: a suspension bracket with a base, a laterally and upwardly extending arm, a supporting head conformed to the track surface, an aperture for a track-securing screw, and an upstanding lug interfitting with a ceiling-suspended support. On that reconstruction, claim 8 is a species of claim 3 and falls to the same claim-3 combination; the conformed "supporting head" is a predictable mating-surface detail (rationale (4)). I cannot state claim 8's exact metes and bounds, and any rejection of it would require the certified copy of the printed patent.

5. Summary of rejection strength

6. Secondary considerations (Graham factor 4)

The record contains essentially one secondary-consideration assertion, at the end of the specification: "My curtain system is admirably adapted for hospital use, where it has met with considerable success."

• Commercial success: asserted, not evidenced. There is no sales data, no market-share showing, and — critically — no nexus to the claimed subject matter. Hospital adoption of suspended cubicle track in the 1930s was driven by sanitation policy (curtains clearing the floor, as the specification itself stresses), not by the particular bracket or track-overlap geometry of any given claim. Under In re GPAC, weak evidence of nexus gets weak weight.
• Long-felt need: at most ~10–15 years, and the need (cubicle privacy) was already being met by the admitted three-curtain systems. A "need" that is partially met is not the classic long-felt-but-unmet need.
• Failure of others: none in the record. To the contrary, the page's later art (US2639041; US2706306) shows others succeeded in the same design space within two decades, which is evidence the space was readily enterable.
• Unexpected results: none asserted, and none apparent. Every advantage recited (no gaps; single curtain for three sides; free hook passage; ventilation; sanitation; standardization) is either the intended function of the claimed structure or an inherent property of the admitted prior-art materials (tubular stock cut to length; plated metal).
• Copying/praise: nothing in the record.

Net: no secondary consideration is likely to rebut a prima facie case, except possibly on claims 5–6 where the plaster-preservation feature could support a narrow "unrecognized problem" argument.

7. Legal-standard caveat worth stating explicitly

The § 103 analysis above applies modern Graham/KSR doctrine. That is the correct framework if validity is tested today. But note the historical asymmetry: the patent issued July 16, 1935, and was therefore examined under the pre-1952 "invention" standard, which at the time of grant was informed by the Cuno Engineering "flash of creative genius" language (324 U.S. 1 (1945)) — a more patentee-friendly standard than KSR. A rejection resting on "obvious to try" or on "predictable use of known expedients" would have been considerably harder to sustain in 1935 than it is today. Anyone using this analysis should be clear about which standard is being applied.

Additionally: this patent's anticipated expiration is July 16, 1952 and its status is Expired – Lifetime. An obviousness challenge today would be a historical exercise or a defensive/derivative-use inquiry, not a live validity contest. There is no presumption-of-validity battle to win and no damages to avoid.

8. Uncertainty disclosures and verification plan

What I verified. I retrieved and read substantive content for US757175 (Burland, 1904 — elastic-framework canopy/drapery for caskets, beds and couches; hooks and toggles, no suspended track — its relevance to the track claims is therefore weak), US1524724 (Wagner, 1925 — window-screen hanger using slotted strips, angle clips, screw-and-slot adjustment and brackets attached to a frame), and US1711070 (Suydam, 1929 — chart-exhibiting apparatus on an overhead rail with travelling hangers; I retrieved only the bibliographic record and classification, not the specification, so my characterization of it as a "rail with travelling hangers" is an inference from its class (211/46) and title, not a verified disclosure).

What I did NOT verify — treat these as unconfirmed. I could not retrieve the specifications of US1520265 (Curtain fixture, 1924-12-23), US1475576 (Combination curtain pole and shade holder, 1923-11-27), US1493119 (Combination table and chairs, 1924), US931962 (Disappearing bed, 1909), or US983957 (Quilting-frame, 1911). For these I have only title, date and (for some) classification from the Google Patents "Similar Documents" list. All element-level mappings involving them in § 4 are predictions about what such references typically disclose, not verified disclosures. Two of them (US983957, US1493119) I affirmatively suspect fail the analogous-arts test under In re Bigio / In re Clay and would likely be excluded.

Number-collision caution (repeated for safety). A search for "US1520265" returned a different patent, US1509330 (Wyatt, "Curtain fixture," Sept. 23, 1924). These are not the same document. I have not conflated them, and US1509330 is not on the '579 page's prior-art list. Similarly, "EP 2008579" is an unrelated optics patent (already flagged in an earlier section) and any bare search for "2008579" returning a Brazilian STJ docket, a Tennessee state case, Swedish SFS 2008:579, or Argentine municipal file numbers is a numeral collision, not this patent.

How to close the gaps before relying on this analysis:

1. Obtain the printed patent's front page "References Cited" list — the fetched page does not include it. That is where the examiner's actual art sits, and it will very likely contain the split-clamp and curved-rod references this analysis presently has to infer.
2. Pull the full specifications of US1520265, US1475576, US1493119, US931962, US1711070 from Google Patents or Patent Public Search (ppubs.uspto.gov) and re-map § 4 element-by-element.
3. Run a targeted classification search in A47H (all), A47H15/02, A47H1/02, A47H2001/0205, and A61G7/05 limited to pre-1931 publication, and in the analogous clamp/collar subclasses for the split-sleeve limitations of claims 7, 13, 14 and 18.
4. Verify the renewal-date question (§ 1.2) against the application file; the conclusion is robust, but the critical date should be stated correctly if this is ever written up formally.

Bottom line. On the art actually shown on this page, claims 7, 13, 14, 17 and 18 are the most vulnerable to § 103 (known clamping and under-track bracket expedients applied to a known suspended-curtain problem, with the applicant's own "free hook passage" statement supplying the motivation). Claims 3, 4, 9, 12 and 16 are moderately vulnerable, chiefly on design-economy and rearrangement rationales. Claims 1, 2, 10, 11 and 15 embody the real point of novelty — the parallel/overlapping inter-track geometry — and can be reached on this page only through the applicant's admitted gap problem plus a KSR "finite number of predictable solutions" rationale; that is defensible but not clean. Claims 5 and 6 (the plaster-relieving bracket) are the patentee's best ground and I found no page reference that reaches them.