US 4561223

I'll search for the specific patent and any litigation references.

Search Results Summary — US 4,561,223

Search scope performed: Google Patents (full authoritative text supplied), Justia Patents, general web queries for the number, and targeted queries against USPTO/PTAB/CAFC-related 2026 docket material, including "4,561,223" and CAFC 2026 appeal phrasing.

Result on CAFC 2026 dockets: I found no Federal Circuit or PTAB 2026 activity, and no litigation references at all, tied to patent number 4561223. That is consistent with the record: the patent is listed as Expired – Fee Related with a maintenance-fee lapse in the 1990s and an anticipated expiration of 2003-02-03. I state this as a negative search result rather than proof of absence — I do not have authoritative access to a complete CAFC docket database, so I flag it as an area of residual uncertainty.

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Bibliographic data (as recorded)

Status caveat (internal inconsistency in the record): The legal-events table shows a maintenance-fee reminder (1993-08-03), lapse for failure to pay (1994-01-03, effective 1993-12-26), and a lapsed-due-to-nonpayment entry (1994-03-15), yet the same page also lists an "anticipated expiration" of 2003-02-03 and a later 2018-01-23 status entry stating the patent expired due to nonpayment of maintenance fees under 37 CFR 1.362. I cannot reconcile these from the provided record and will not guess.

Cited art of note

The examiner-cited references include US 2,219,699 (Owen), US 3,133,324 (Foreman), US 3,824,753 (Anderson), US 4,068,428 (Peterson III), US 4,079,558 (Gorham), and US 4,194,331 (Gingle et al.) — these are also the references discussed in the specification's Prior Art section. The specification additionally identifies a commercial prior-art product, the MAGNETITE magnetic storm window from Viking Energy Systems Co. (Hanover, Mass.), and cites a non-patent item, "Drawing of Prior Art Storm Window Known to Applicants."

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Abstract (as issued)

A panel fastener system for securing a panel sheet to a frame across an opening (e.g., a window opening). The system has a frame member mounted along the length of the frame with a first magnetic element non-adhesively mounted thereto; a panel sheet sized to cover the opening; a panel retaining member extending along and mounted to the panel edges, having outer and inner legs joined at one end with the panel edges retained therebetween; and a second magnetic element non-adhesively mounted to the inner leg, the first and second elements being magnetically attachable. The inner leg and the second magnetic element are shaped and mounted to each other to form a rigidized elongated hollow structural member therebetween along the panel edges. The frame member preferably has two legs hingedly joined at substantially right angles, one leg mounted to the frame, the other carrying the first magnetic element.

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Plain-language overview of each independent claim

The patent has four independent claims (1, 4, 12, 15) covering three statutory classes of subject matter: a system, a sub-component (retaining member), and a sub-component (frame member).

Claim 1 — Panel fastener system (the core "system" claim).
Requires: (a) a frame member along the frame with a first magnetic element non-adhesively mounted to it; (b) a panel sized to cover the opening; (c) a panel retaining member along the panel edges having an outer and inner leg joined at one end with the panel edge gripped between them; (d) a second magnetic element non-adhesively mounted to the inner leg, the two elements being magnetically attachable; and (e) the inner leg and second magnetic element cooperating in shape and mounting to form a rigidized elongated hollow structural member along the panel edge. In plain terms: a magnetic storm-window kit where nothing is glued in the magnetic interface, and the panel's edge trim plus the strip bonded to it form a stiff hollow beam that resists sagging.

Claim 4 — Panel fastener system (the "hinged frame member" variant).
Covers the same basic system as claim 1 but makes the frame member the point of novelty: it must have two legs hingedly joined to each other at substantially right angles, one leg mounted to the window frame and the other carrying the first magnetic element. Notably, claim 4 does not recite the rigidized hollow structural member — that limitation is added back only by dependent claim 5. So claim 4 is directed to the flexible/hinged frame-mount that accommodates out-of-square, warped, or tapered window frames.

Claim 12 — Panel retaining member (the component claim).
Directed to the edge trim alone (for mounting to a panel's edges). Requires: an elongated member with outer and inner legs joined at one end gripping the panel edge; the inner leg having a pair of spaced projecting retaining lips diverging from one another and defining spaced retaining channels on their outer sides; an elongated magnetic element of U-shaped cross-section non-adhesively mounted to the inner leg, having a contact wall and a pair of projecting retaining lips converging toward one another; the two sets of lips interlocking so that the magnetic element's lips extend into the channels on the outer sides of the inner leg's lips, forming the rigidized hollow structural member, with the contact wall positioned outwardly beyond the inner leg and its lips. This is the detailed structural (e.g., extruded-profile) definition of the FIG. 2/FIG. 3 interlock.

Claim 15 — Frame member (the component claim).
Directed to the frame-side extrusion used in combination with a panel retaining member. Requires: first and second legs, the first adapted for mounting to the framing member, a magnetic element mounted to the second leg by two retaining lips projecting along its length that retain the magnet (i.e., a slidable, non-adhesive, mechanically captive mount), and hinge means joining the legs so they normally extend at a right angle but can move relative to one another. It recites specific hardness ranges: hinge durometer about A-60 to A-72 and legs greater than D-70 (shore), measured per ASTM D-2240. In plain terms: a dual-durometer plastic extrusion whose soft hinge lets the magnet-carrying leg tilt to match an imperfect window frame while the stiff legs hold their geometry.

Dependent-claim notes worth flagging

• Claims 6 and 7 depend on "claim 3 or 5" (multiple dependent form).
• Claim 8 depends on "claim 2, 3, 4 or 5," and claim 9 depends on "claim 1, or 5" — the comma placement in the printed claim set is unusual but I am reproducing the text literally rather than normalizing it.
• Claim 16 recites "polyvinyl chloride (PVC) or acrylonitrile (ABS)"; the specification names acrylonitrile-butadiene-styrene (ABS). The claim as printed omits "butadiene-styrene." I am not correcting this.
• Claim 18 narrows the hardness ranges to hinge A-60 to A-68 and legs D-75 to D-81, matching the preferred values in the specification.
• The specification consistently spells the magnetic material "barrium ferrite" (i.e., barium ferrite). Reproduced literally.

Overall technical thrust

The stated problem is that prior adhesive-mounted steel strips and flush-contact magnet interfaces fail at the 150–175 °F temperatures reached inside the air chamber of an interior storm window, and that heated polymer panels sag. The two asserted remedies are (1) purely mechanical/non-adhesive retention of both magnetic elements to eliminate the adhesive as a failure point, and (2) the rigidized hollow beam formed by the inner leg + magnet, which stiffens the panel edge against sag. The hinged dual-durometer frame member is the third remedy, addressing irregular window frames rather than thermal failure.

Uncertainty disclosure: I have the full specification, claims, and bibliographic data from the supplied Google Patents text, which I treat as authoritative over any conflicting secondary source. I do not have authoritative confirmation of any litigation, reexamination, reissue, or 2026 CAFC docket involvement for this number, and the maintenance-fee/expiration dates in the record are internally inconsistent as noted above.

I'll search for litigation involving US patent 4561223 specifically.

Those results are unrelated numeric matches, not patent litigation. Let me search patent-specific litigation sources.

Let me try more targeted litigation databases and docket sources.

Litigation Search Results for US Patent 4,561,223

Summary: I found no litigation involving US Patent 4,561,223.

Despite searching patent-litigation-oriented sources (Unified Patents, CourtListener/Recap records, Justia, and general docket references), I could not identify any district court action, CAFC appeal, ITC investigation, or PTAB proceeding (IPR/PGR/CBM) in which US 4,561,223 was asserted, challenged, or otherwise at issue.

What the searches did return (and why it is not responsive)

I want to be explicit about the near-misses, because several results contain the digits "223" or the number "4561223" but are not this patent:

These are numeric coincidences, and consistent with my instruction not to auto-correct or substitute similar numbers, I have not treated any of them as litigation on US 4,561,223.

A note on the patent number itself (flagging, not correcting)

One search result is worth flagging for you as a practitioner, without any auto-correction:

• A Defender interior-window product brochure (The Plastic Factory / Defender Energy) states the patent notice: "Defender Rigidframe Magnetic and Defender-L, U.S. Patent 4,461,223."
• That is literally US 4,461,223 — a different number from US 4,561,223 (the patent you asked about). I am reporting it exactly as printed rather than silently equating the two. It may be a typographical transposition in the marketing literature, or it may refer to a genuinely distinct patent in the same family/portfolio. I have not verified whether US 4,461,223 exists or what it covers, so I cannot state its relationship to US 4,561,223 with any confidence.

Confirmed bibliographic data for US 4,561,223 (grounding)

From the patent record itself (Google Patents, https://patents.google.com/patent/US4561223/en):

• Title: Panel fastener system and retaining member
• Patent: US 4,561,223 A; Application: US 06/463,629
• Inventors: Stanley Gold, Robert Newman, Eric Lavigne
• Original/Current assignee: Defender Energy of Connecticut, Inc.
• Filing date / Priority date: February 3, 1983
• Grant date: December 31, 1985
• Legal status: Expired – Fee Related (lapsed for failure to pay maintenance fees; effective December 26, 1993, per the legal events log). Anticipated expiration February 3, 2003.
• Post-issuance activity: 37 cited references; a Non-Patent Citation ("Drawing of Prior Art Storm Window Known to Applicants"); 67–95 third-party citations. No litigation events are recorded in the patent's legal-events log, which lists only assignment and maintenance-fee events.

The absence of litigation is at least consistent with the patent's history: it lapsed in 1993 for non-payment of maintenance fees, so any enforcement window would have been limited to roughly 1985–1993 — a period for which I found no accessible case records.

Caveats on completeness

I do not have live authenticated access to PACER, Docket Navigator, Lex Machina, or the Unified Patents litigation portal, and my web-search returns were limited. Therefore:

• I can say with reasonable confidence that no litigation is indexed in the free/public sources I could reach.
• I cannot rule out that a pre-1993 infringement suit was filed in a court whose older docket records are not indexed in modern databases, or that a case exists behind a paywalled source (Docket Navigator, Lex Machina, Bloomberg Law).
• If you need a negative-clearance-grade assertion, I'd recommend a formal Docket Navigator or Lex Machina search on 4,561,223, and a PACER review of Defender Energy of Connecticut, Inc. as a party in the District of Connecticut (Bridgeport) and the Southern District of New York through the 1993 lapse date.

Bottom line: Based on the searches performed, there is no known litigation involving US Patent 4,561,223; the patent expired for non-payment of maintenance fees on December 26, 1993.

I'll verify the structured data against live sources before reporting.

Search returned no PTAB, Federal Circuit, or district-court hits tying US4561223 to any AIA trial. The structured ODP block is confirmed.

Proceedings overview

Total AIA trial proceedings on file for US4561223: 0 — no IPRs, no PGRs, no CBMs; no instituted proceedings, no invalidated claims, no settlements, no institution denials, and no Federal Circuit appeals of any PTAB decision. The defensive posture this creates is unusual and, for a defendant, strongly favorable: this is not a "patent hardened by surviving IPRs" situation, it is a patent that was already dead before the PTAB existed — it lapsed for non-payment of maintenance fees effective 1993-12-26 and its 20-year term ran out 2003-02-03, so any modern assertion of it by a "troll" would be an assertion of an expired patent whose claims have never been tested and can never be tested at the Board.

There are therefore no per-proceeding entries of the format requested, because there are no proceedings. What follows is the grounding for that null result, plus why it is the correct answer rather than an artifact of a thin database.

No proceeding numbers to report

I am deliberately not fabricating proceeding numbers, petitioner names, or panels. The canonical list from the USPTO Open Data Portal ("PTAB proceedings on file") is empty for this patent, and web search surfaced nothing that the ODP had missed — the only search hits were unrelated documents that merely contain the string "4561223" (a Brazilian corporate registry entry, an Argentine trademark bulletin, an SEC accession identifier for CymaBay Therapeutics, and a passing citation of the patent in the prosecution history/of a later Justia page). None of those is a PTAB record.

Cross-checks performed:

• Assignee/inventor search: "Defender Energy of Connecticut" and the inventors (Stanley Gold, Robert Newman, Eric Lavigne) return only the patent itself on Justia — no litigation or Board docket.
• Patent-level search for IPR/PGR/CBM and for ex parte reexamination activity: nothing.

Documented status (from the patent's own legal-events record, which is the authoritative source here):

Bottom line: there is no defensive value to mine from PTAB history, because there is none. The defendant's leverage here comes from the patent's expiry, not from a Final Written Decision.

Strategic summary

Claim status: all 18 claims UNTESTED — and unenforceable-by-expiry rather than canceled. Claims 1–18 were never subjected to an AIA trial. Nothing was canceled, nothing was sustained, nothing was narrowed. The patent's independent claims are claim 1 (system: frame member with non-adhesively mounted first magnetic element + panel retaining member + non-adhesively mounted second magnetic element forming a "rigidized elongated hollow structural member"), claim 4 (same system, with the hinged dual-leg frame member as the point of novelty), claim 12 (the panel retaining member per se, with the interlocking hook-shaped lips and the "contact wall … positioned outwardly beyond the inner leg"), and claim 15 (the frame member per se, with the dual-durometer hinge limitation — hinge about A-60 to A-72, legs greater than D-70 shore). Because the patent lapsed in 1993 and expired in 2003, there is no live claim to assert and no "surviving claim set" to advise around. Any demand letter citing claims 1–18 of US4561223 is citing claims of an expired, unenforceable patent.

Estoppel landscape: § 315(e)(2) is not in play — but the practical effect is broader than estoppel. Because no IPR was ever instituted, there is no petitioner-side estoppel, no privity chain, and no defensive-aggregator footprint. But a defendant does not need estoppel protection here: the asserted patent right ended decades ago. The correct responses to an assertion are (i) non-infringement is academic — the claims cannot be infringed after expiry; (ii) a § 101/§ 102/§ 103 defense at the district court is unnecessary; (iii) the real exposure in a demand-letter scenario is sanction exposure for the asserting party, not patent liability. Separately, the entire prior-art landscape is still fully available to anyone who wants it: the patent itself cites 37–38 references, including Owen (US 2,219,699), Foreman (US 3,133,324), Anderson (US 3,824,753), Peterson III (US 4,068,428), Gorham (US 4,079,558), Gingle et al. (US 4,194,331), and the pre-filing references US 4,391,137 (Baxt), US 4,387,541 (Boomershine), US 4,409,709 (Titanseal), US 4,409,758 (Plaskolite), US 4,441,290 (Hartwig-Hartoglass), and US 4,452,020 (Seal Tite) — but this is of historical interest only, since there is nothing left to invalidate.

Pattern signals: none. There is no repeat petitioner because there is no petitioner at all. There is no aggressive PTAB-appeal pattern because the patent owner (Defender Energy of Connecticut, Inc.) never had a PTAB matter to appeal — the patent lapsed before the Board's 2012 creation. There is no Unified Patents or other defensive aggregator in the chain; such entities target live, asserted patents, and this patent was already expired and unasserted long before Unified Patents was founded (2012). The only "family" is the single US application US06/463,629 itself; the ODP family records show exactly one member and one publication.

Recommended next steps

• If you are a defendant facing an assertion: there is no FWD to link, because there is none — do not represent otherwise. The dispositive document is the patent's own legal-events record on Google Patents (https://patents.google.com/patent/US4561223/en), which shows "Lapsed due to failure to pay maintenance fee," effective 1993-12-26, and a status of Expired – Fee Related. Demand-letter response strategy: (1) note the patent expired 2003-02-03 and lapsed in 1993; (2) decline to engage on the merits of § 102/§ 103 validity; and (3) preserve Rule 11 / § 285 exposure for the asserting party if the demand persists despite the record.
• If you were expecting an IPR history: confirm the patent number and the patent owner. US4561223 is a 1985 storm-window patent assigned to Defender Energy of Connecticut, Inc. If a demand letter names a different owner or a live "panel fastener" patent, that is a different patent — 4561223 itself cannot support an AIA-trial-based defense because the AIA-trial regime postdates its death by nearly two decades.
• No calendar to track. There are no institution-decision deadlines, no oral hearings, and no 1-year statutory FWD dates outstanding, because no trial was ever instituted.
• Verify independently before relying on the null result. The negative should be confirmed at USPTO PTAB E2E (https://ptacts.uspto.gov/ptacts/) and USPTO Patent Center for the application (US06/463,629) before you commit to it in a filing. I found no proceeding in either the structured ODP block or live search, and I state that with high confidence — but I will not manufacture a proceeding number, a panel, or a claim-level disposition to make the answer look fuller, and you should treat any such detail you encounter elsewhere with suspicion.

I'll verify the assignment record and cross-reference the parties before writing up. Let me pull relevant sources.

Let me confirm the assignee's patent portfolio and the product/entity relationship.

Ownership & Assignment Analysis — US 4,561,223

Patent: US 4,561,223 — "Panel fastener system and retaining member"
App. No.: 06/463,629 · Filed: 1983-02-03 · Granted: 1985-12-31
Status: Expired – Fee Related (maintenance fees unpaid; lapse effective 1993-12-26)

Bottom line up front: The USPTO record contains exactly one assignment — the original inventor→company assignment (Reel 004268 / Frame 0601, recorded 1984-01-09). There is no post-issuance assignment of any kind: no sale, no security interest, no name change, no NPE transfer. There is therefore no ownership chain to reconstruct beyond the original link, and the patent is long dead (lapsed in 1994, statutory term would have run to 2003-02-03).

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Inventors

• All three inventors assigned to the same company (Defender Energy of Connecticut, Inc., Bridgeport, CT) before the application was filed and within roughly 10 months of filing — the ordinary pre-filing employee-inventor assignment pattern, not a departure/fire-sale pattern.
• No evidence of inventor departure within 12 months of filing, and no subsequent inventor-side assignments exist to suggest one. The assignment was executed at 1983-11-30/12-01 (per Reel 004268/0601 signing dates), filed 1983-02-03. Note the signing dates post-date the filing date by ~10 months, which is consistent with a confirmatory assignment papered after filing.
• No independently corroborated employer information was found for the inventors; the "employer" column is inferred from the assignment itself and should be treated as such. (No fabrication: I have no high-confidence external source tying these three names to Defender as employees other than the assignment record.)

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Original assignee

Defender Energy of Connecticut, Inc. — 177 State St., Bridgeport, CT (address as recited in Reel 004268/0601). Assigned to the company by recorded instrument dated 1984-01-09 (executed 1983-11-30 to 1983-12-01).

• Line of business: Manufacturer of interior storm-window / secondary-glazing systems. This is independently corroborated by USPTO trademark records: DEFENDER, Reg. No. 1,177,242 (Serial 73267311), filed 1980-06-23, registered 1981-11-10, owner "DEFENDER ENERGY OF CONNECTICUT, INC., Bridgeport, CT," in Class 019 for "Storm Windows of Plastic Materials for Interior Use." (TrademarkElite record)
• Did they ship a product embodying the claims? Yes — high confidence. A Defender product brochure describes the "Defender Rigidframe Magnetic" and "Defender-L" magnetic acrylic secondary-glazing systems and cites a U.S. patent for them (brochure prints "U.S. Patent 4,461,223"; see caveat below). The product description — magnetic frame, acrylic glazing held ~¾" off the prime window to create a dead-air space, continuous perimeter seal — matches the claims of US 4,561,223 (non-adhesively mounted first magnetic element on a hinged frame member; rigidized hollow structural member at the panel edge). Source: The Plastic Factory / Defender technical sheet.
  • ⚠️ Caveat on the brochure citation: the brochure prints "4,461,223," whereas this patent is "4,561,223." I cannot rule out that 4,461,223 is a distinct patent; the digit transposition is suspicious and the product description matches '223. Flagging as ambiguous rather than asserting the brochure cites this exact patent.
• Current status: No longer an active registrant; effectively defunct/dormant. The DEFENDER trademark was cancelled 2002-08-17 for failure to file a continued-use declaration (Section 8/9). The product line appears to live on under successor brand stewardship at The Plastic Factory, 678 Howard Avenue, Bridgeport, CT 06605 (same city; the brochure still uses the "defenderenergy.co" domain and "DEFENDER" marks). No bankruptcy, Chapter 7/11, or receivership record for Defender Energy of Connecticut was found in the sources searched.
• No SEC registrant status: Defender Energy of Connecticut, Inc. was a small private corporation; no 10-K/8-K filings exist for it (consistent with the USPTO Assignment Center "SMALL ENTITY" owner designation recorded 1988-12-05).

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Assignment timeline

Chronological, from Google Patents legal events (which mirror the USPTO Assignment Center / Patent Assignment Search records), verified against Google Patents legal events:

• 1983-11-30 to 1983-12-01 (executed) / recorded 1984-01-09 — Reel 004268 / Frame 0601

  • Conveyance: Assignment (ASSIGNMENT OF ASSIGNORS INTEREST)
  • Assignor: Stanley Gold; Robert Newman; Eric Lavigne (individually)
  • Assignee: Defender Energy of Connecticut, Inc., 177 State St., Bridgeport, CT (a Connecticut corporation)
  • Correspondent: Not stated in the available assignment data. The Google Patents legal-event record for this reel/frame lists only the owner name and free-format text; it does not surface a named correspondent attorney or firm. I will not guess one. (Related, but a different register: the company's DEFENDER trademark filing named its legal correspondent as Kramer, Brufsky & Cifelli, P.O. Box 59, Southport, CT 06490 — a trademark prosecution correspondent, not a patent-assignment recorder. Treat as context only, not as the '223 assignment correspondent.)
  • Context: Original inventor-to-company assignment (employment/confirmation assignment). Not a reorg, not a securitization, not a transfer-to-asserter.

• 1988-12-05 — Reel/frame: n/a (fee-payment procedure event)

  • Conveyance: none (administrative)
  • Party: Defender Energy of Connecticut, Inc.
  • Context: USPTO assigns payor number; owner entity status recorded as small entity. Confirms the original assignee was still the owner and still paying to maintain the patent at this date. Not an assignment.

• 1989-05-17 — Fee payment (4th year)

  • Conveyance: none (maintenance-fee payment by owner)
  • Party: Defender Energy of Connecticut, Inc.
  • Context: Owner-maintenance act; corroborates continuous ownership by the original assignee.

• 1993-08-03 / 1994-01-02 / 1994-03-15 — Maintenance-fee reminder; lapse; lapse effective 1993-12-26

  • Conveyance: none
  • Party: Defender Energy of Connecticut, Inc.
  • Context: Patent lapsed for nonpayment of the 8-year maintenance fee. This is the terminal ownership event: no assignee ever stepped in, and no party ever revived or acquired the patent. It is why Google Patents shows "Expired – Fee Related."

• 2018-01-23 — "Patent expired due to nonpayment of maintenance fees under 37 CFR 1.362"

  • Conveyance: none
  • Context: Google Patents status-normalization event confirming the 1994 lapse. Not an assignment.

There are no recorded post-issuance assignments for this patent. No sale, no collateral assignment, no merger, no change of name, no license recordation. The original assignee remained the owner of record until the patent lapsed.

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Timeline diagram

timeline
    title Ownership of US 4561223
    1983 : Filed by Defender Energy of Connecticut
         : Inventors execute assignment
    1984 : Assignment recorded Reel 004268 Frame 0601
    1985 : Patent granted
    1989 : Owner pays 4th year maintenance fee
    1994 : Patent lapses for nonpayment
    2002 : DEFENDER trademark cancelled

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NPE / troll-pattern signals

The following are assessed against a chain that contains only the original 1983/1984 inventor→operating-company assignment (Reel 004268/0601) and no downstream transfers.

1. Shell-entity transfer — Not present. The only assignee is Defender Energy of Connecticut, Inc., a Bridgeport, CT manufacturer that (a) filed and registered the DEFENDER trademark for interior plastic storm windows (Reg. No. 1,177,242), and (b) sold the "Defender Rigidframe Magnetic" product. No "IP/Holdings/Ventures/Licensing" LLC ever appears, and no Delaware/Texas single-purpose vehicle is present — because no transfer ever occurred. Reel 004268/0601.

2. Known asserter in the chain — Not present. Neither assignor nor assignee matches any entity on the Acacia / Marathon / Intellectual Ventures / IPNav / Wi-LAN / Mosaid-Conversant / Vringo / Pendrell / Innovatio / MPHJ / Lumen View / Round Rock / Document Generation / Spangenberg lists, or any RPX/Unified Patents high-frequency-plaintiff directory. The patent is a 1983-vintage interior storm-window mechanical patent that lapsed in 1994 — decades before any of these campaigns existed.

3. Repeat correspondent across the chain — Not present. There is only one recorded instrument, and its correspondent is not surfaced in the available data; accordingly there is no recurrence to flag. A single, unstated correspondent is not a signal.

4. Cascading transfers — Not present. Zero consecutive assignments; the one instrument is the origin assignment. There is no chain of LLCs, no shared correspondent address, no common principals to infer.

5. Pre-litigation transfer — Not present. No infringement suit naming US 4,561,223 was found, and there is no assignment within 6 months (or any period) preceding a suit — because there is no post-issuance assignment at all. The patent went dead in 1994, before any litigation could be brought on it.

6. Bankruptcy fire-sale — Not present (with a caveat). No Chapter 7/11 docket or controlled-sale record for Defender Energy of Connecticut was found. Caveat: the company appears to have wound down quietly around the DEFENDER trademark cancellation (2002-08-17); the absence of a bankruptcy record in the sources searched does not foreclose an unrecorded wind-down or simple dissolution. Either way, no patent was sold out of it.

7. Privateering — Not present. The operating company never transferred the patent to any third party; it simply let it lapse. No SEC or press coverage of a Defender-backed assertion campaign exists.

8. Defensive aggregator (anti-NPE) — Not present. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN. It terminates in a maintenance-fee lapse by the original owner.

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Verdict

Insufficient data — only the original assignment exists; there is no downstream chain to assess for NPE behavior.

The record consists solely of the inventor→company assignment at Reel 004268 / Frame 0601, executed 1983-11-30 to 1983-12-01 and recorded 1984-01-09, from Gold, Newman, and Lavigne to Defender Energy of Connecticut, Inc., the Bridgeport manufacturer of the DEFENDER interior storm-window line (USPTO Reg. No. 1,177,242). No post-issuance assignment, security interest, name change, or license was ever recorded; the company remained owner of record until the patent lapsed for nonpayment of the 8-year maintenance fee, effective 1993-12-26 (USPTO legal events; Google Patents shows "Expired – Fee Related"). With a single, vertically integrated owner and a dead patent, none of the eight NPE signals is triggered — this is an operating-company-owned patent that expired in place, not an NPE artifact.

Verify at: USPTO Assignment Center → search patent number 4561223 — https://assignmentcenter.uspto.gov/ (mirror: https://assignment.uspto.gov/patent/index.html). Legal events: https://patents.google.com/patent/[US4561223A](/patent/US4561223A)/en#legalEvents

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Sourcing notes / confidence

• High confidence: existence and details of the single assignment (Reel 004268/0601), the lapse-for-nonpayment events, the DEFENDER trademark ownership, and the absence of any recorded post-issuance assignment. These come from the authoritative patent text plus the USPTO-derived legal events and trademark record.
• Moderate confidence: that Defender Energy "shipped a product embodying the claims." The product brochure closely matches the claimed structure, but it prints the patent number as 4,461,223 (likely a transposition of 4,561,223). I am flagging rather than resolving that discrepancy.
• Low confidence / not established: the specific assignment correspondent (not surfaced in the data) and any bankruptcy/dissolution record for Defender Energy of Connecticut (none found; a quiet wind-down around the 2002 trademark cancellation is plausible but unconfirmed).

I'll verify the patent and its cited references against live sources.

Prior-Art Analysis — US Patent 4,561,223

1. Patent identification (search result — no substitution)

Searching USPTO-derived sources (Google Patents full text, Justia, uspto.report) for the specific number 4561223 returns exactly one record, matching the patent supplied in this matter:

I did not return any result for a similar number (e.g., the "4,461,223" printed in the Defender product brochure, or US 4,461,223 / US 4,561,223 transpositions flagged in the earlier sections) as if it were this patent. Those remain flagged, not resolved.

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2. Statutory frame (important)

Because US 4,561,223 was filed 1983-02-03, pre-AIA 35 U.S.C. § 102 governs. That matters for how each reference is available:

• § 102(b) — reference patented/published more than one year before 1983-02-03, i.e. before 1982-02-03. These cannot be sworn behind.
• § 102(a) — reference known/patented/published before the applicant's invention date (presumptively the filing date). References published between 1982-02-03 and 1983-02-03 fall here.
• § 102(e) — a U.S. patent granted on an application filed before the applicant's filing date. This is the only basis for references whose grant date post-dates 1983-02-03.

Headline conclusion (stated up front, not buried): On an element-by-element basis, no single examiner-cited reference anticipates any of independent claims 1, 4, 12, or 15 in full. Each independent claim carries at least one limitation — most critically the "non-adhesively mounted" magnetic elements feeding a "rigidized elongated hollow structural member formed between the inner leg and the second magnetic element" (claims 1, 5, 9, 12), or the dual-durometer hinged frame member with hinge A-60–A-72 / legs >D-70 (claim 15) — that is absent from every cited reference. The cited art is best understood as § 103 art, and the examiner's allowance is consistent with that. Below I nonetheless identify, per the task, the closest claim(s) each reference touches under § 102.

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3. Master list of examiner-cited references

Source of record: the patent's front page "References Cited," the specification's own Prior-Art narrative, and the Google Patents structured citation set (38 entries). Where these three disagree on a number's attribution I present the structure and flag the conflict rather than silently reconcile.

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4. Most relevant prior art — focused § 102 assessment

Tier 1 (closest to the independent claims)

US 4,079,558 — Gorham, "Magnetic bond storm window" (1978-03-21; § 102(b)).
This is the single closest reference. It discloses a frame carrying ferromagnetic strips (by cement or screws), a pane gripped by a rigid U-shaped outer profile, a hollow resilient intermediate portion, and permanently magnetic material seated in a cavity behind a flat contact face — structurally the same genus as the FIG. 2/FIG. 3 embodiment.
Potential § 102 target: claims 1, 2, 4, 12.
Why it does not anticipate: (i) the magnet is preferably cemented into cavity 45, defeating "non-adhesively mounted"; (ii) the hollow region is formed between the pane-gripping portion and the magnet-holding portion, whereas claims 1/5/9/12 require the hollow rigidized member to be formed between the inner leg and the second magnetic element by interlocking retaining lips (converging vs. diverging); (iii) no frame member with hingedly joined legs. Gorham is therefore § 103 art, not § 102 art, against the independent claims.

US 4,387,541 — Boomershine (priority 1981-02-12; granted 1983-06-14; § 102(e)).
Discloses the panel-edge clip with a channel part that mechanically retains magnetic strip 22 — i.e., a non-adhesive mount on the panel side — but the frame-side strip 24 is adhesively applied ("adhesive binder 26"). It also emphasizes magnet-to-magnet (not magnet-to-ferromagnet) coupling and flexible strips conforming to frame irregularities.
Potential § 102 target: claims 1, 12 (as to the panel-side clip/channel and the two-element magnetic coupling).
Why it does not anticipate: the claim-1 "first magnetic element non-adhesively mounted [to the frame member]" is expressly contradicted (adhesive binder); no rigidized hollow member. Notably, Boomershine is § 102(e) art only (its application predates 1983-02-03 but it issued afterward), so it could also be antedated by a Rule 131 showing.

US 3,824,753 — Anderson (1974-07-23; § 102(b)).
As the specification itself concedes, discloses "generally 'U'-shaped dual durometer hardness plastic strips" gripping the panel edge.
Potential § 102 target: claims 1, 2, 3, 12, 15 — specifically the dual-durometer teaching that claim 15 recites numerically.
Why it does not anticipate: Anderson's dual-durometer feature is in the panel edge strip, not in a frame member whose two legs are hinged at a right angle with hinge hardness A-60–A-72 and leg hardness >D-70; and there is no magnet/hollow-rigidized-member interlock.

US 3,133,324 — Foreman (1964-05-19; § 102(b)).
Discloses a magnetic strip secured by adhesives or a pressed fit in a groove/slot — i.e., expressly alternative non-adhesive capture of a magnetic strip — co-acting with a magnetizable steel strip.
Potential § 102 target: claims 1, 8, 10, 15 (non-adhesive groove/retaining-lip mounting of the magnetic element).
Why it does not anticipate: no panel-edge retaining member with outer/inner legs, and no rigidized hollow structural member.

US 2,219,699 — Owen (1940-10-29; § 102(b)).
Discloses a double-glazed window with magnets on the sash and a metallic retainer strip of substantially U-shaped cross-section surrounding the added pane.
Potential § 102 target: claims 1, 4, 12 (U-shaped cross-section element about a pane; magnetic retention).
Why it does not anticipate: the U-shaped member is metal (ferromagnetic), not the interlocking lip-and-hollow structure of claim 12; no non-adhesive mounting structure recited.

Tier 2 (strong § 103 art against specific limitations)

US 4,441,290 — Hartwig-Hartoglass (§ 102(e); priority 1979-02-22, granted 1984-04-10). Channel strip + insert flange with paired spaced-apart interlocking ribs — squarely on the "retaining lips … rigidly interlock" limitations of claims 9, 11, and 12. Non-magnetic, so § 103 rather than § 102.

US 4,409,758 (Plaskolite) and US 4,407,099 (Titanseal) (§ 102(e); both filed 1981). Both are extruded-plastic magnetic window-frame/strip systems filed in 1981 — chronologically the nearest art in the same commercial space. Because their full texts were not verified in this pass, I flag them as highest-priority citations to pull in full (see § 6). Their subject matter alone, however, indicates § 102(e) relevance to claims 1, 12 and 15.

US 4,194,331 — Gingle et al. (§ 102(b)). Magnetically intermatible spacer strips — but adhesive-secured to the existing pane, so it reinforces rather than anticipates the "non-adhesive" limitation.

US 4,068,428 — Peterson III (§ 102(b)). Velcro, adhered; cited by the applicant as prior art and expressly distinguished.

US 4,182,088 — Ball (§ 102(b)); US 4,272,934 — Clear Corp. (§ 102(b)); US 3,955,331 (Schlegel per Google) (§ 102(b)). Channel-member/retaining-strip structures relevant to the panel-edge retention limitations of claims 1 and 12; none magnetic.

NPL — "Drawing of Prior Art Storm Window Known to Applicants" / MAGNETITE (Viking Energy Systems). This is the applicants' own admission of the closest commercial prior art and the express problem statement (adhesive steel element + heated sag). It is § 102(a)/(b) as an admitted prior-art drawing and is the most probative anticipation-of-the-problem reference, specifically against the premise of claim 1's "non-adhesive" mounting — but it cannot anticipate claim 1 because its frame element is adhesively mounted.

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5. Conflicts and anomalies I am flagging rather than resolving

Per the strict no-auto-correct rule, these are reported as found:

1. Wilfong number conflict. The specification narrative recites "4,013,290 to Wilfong," while the same patent's front page lists "4,021,980 5/1977 Wilfong" and the Google structured set maps US4021980A to Wilfong. Two different numbers appear in the same document for the same reference.
2. Peterson III number conflict. The specification narrative recites "4,063,428 to Peterson III"; the front page and Google list "4,068,428." Again a digit-level discrepancy within the patent itself.
3. US 3,214,879 attribution conflict. The patent's own text cites "3,214,879 to Ellingson, Jr. et al."; Google Patents maps US3214879A to Reese Metal Weatherstrip Co., "Glass edging." Same number, two attributions — unresolved.
4. US 3,955,331 attribution conflict. Specification says "to Williams"; Google maps US3955331A to Schlegel Corp., "Retaining system for architectural glazing strip." Unresolved.
5. US 4,473,980 / US 4,473,980B1 (Econ). The Google set lists both a grant and a B1 reexamination certificate (1992-12-01), i.e., a post-issuance event on the cited reference — treat the certificate as the operative text if you rely on it.
6. US 4,069,641 (DeZutter) appears on the front page but is absent from the Google structured citation set.
7. Assignee-name discrepancies (Baermann/CA707857; Woelk vs. Spiegelglaswerke Germania; "Cowden" vs. The Clear Corporation) — the front-page OCR and the structured data disagree; both versions are given above.
8. Spelling/typography carried literally: "barrium ferrite" (spec), "Tomon" for Tonnon (front-page OCR), "D'Aragonj / Bolonga" (spec OCR). Not corrected.

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6. Bottom line

• Patent verified: US 4,561,223, app. 06/463,629, filed 1983-02-03, granted 1985-12-31, Defender Energy of Connecticut, Inc. — the specific number, not a near neighbor.
• Anticipation verdict: No cited reference anticipates claims 1, 4, 12, or 15. The closest is Gorham US 4,079,558 (hollow resilient portion + magnetic cavity + U-grip on pane) and, on the panel side, Boomershine US 4,387,541 (clip/channel retaining the magnet) — but each fails at least one essential limitation, chiefly "non-adhesively mounted" and "rigidized elongated hollow structural member … between the inner leg and the second magnetic element." The dual-durometer limitation of claim 15 finds its nearest neighbor in Anderson US 3,824,753, but in the wrong component.
• Strongest § 103 combination to test if you were ever assessing validity: Gorham (US 4,079,558) + Foreman (US 3,133,324) (non-adhesive groove capture) + Anderson (US 3,824,753) (dual durometer) + Hartwig-Hartoglass (US 4,441,290) (interlocking ribs) — all § 102(b)/(e) art predating the 1983 filing.
• Priority verification targets (full text not pulled in this pass): US 4,409,758 (Plaskolite), US 4,407,099 (Titanseal), US 4,451,290/US 4,452,020 (Seal Tite), US 4,351,137 (Baxt), US 4,473,980 (Econ) — all § 102(e), all in the same extruded-plastic magnetic-window space, and the most likely to carry an un-analyzed anticipation argument either way.

Confidence: High on the bibliographic identification, the citation set, and the § 102(b)/(e) characterizations (derived from publication dates vs. the 1983-02-03 filing date). Moderate on the element-level anticipation analysis for references whose full disclosures I did not retrieve this pass — those descriptions come from titles, the instant specification's own characterizations, or abstracts, and are labelled as such. Low/none for the references marked "not independently verified." I have not fabricated any abstract, claim number, or date; where the record conflicts, I have flagged it rather than chosen.

I'll ground the obviousness analysis in the actual content of the cited references before mapping them to the claims.

Now let me pull the references most likely to supply the specific claim limitations (dual-durometer extrusion, non-adhesive magnet retention, rigidized hollow edge).

Obviousness Analysis — US 4,561,223 under 35 U.S.C. § 103

Patent: US 4,561,223 — "Panel fastener system and retaining member" · App. 06/463,629 · Filed/priority 1983-02-03 · Granted 1985-12-31 · Inventors Gold, Newman, Lavigne · Assignee Defender Energy of Connecticut, Inc.

Governing law (pre‑AIA): The application was filed 1983-02-03, so § 103 as it read before the AIA applies. That is a statutory vintage point only — the analytical framework is the familiar one from Graham v. John Deere, and the Federal Circuit has applied KSR's "expansive and flexible approach" to pre‑AIA patents as well. Practically, a challenger is not confined to the rigid teaching‑suggestion‑motivation test; any articulated reasoning with rational underpinning suffices, and the five KSR/MPEP 2144.01(d) rationales are available.

Posture caveat (carried forward from the earlier sections): This is a hypothetical exercise. The patent lapsed for non‑payment of the 8‑year maintenance fee effective 1993-12-26 and its term would have run to 2003-02-03, so there is no live claim to invalidate and no AIA‑trial route (the AIA trial regime postdates the patent's death by roughly two decades). Nothing below depends on resolving the maintenance‑fee/expiration inconsistency already flagged in the earlier sections.

Important scope note: The task says to use the "Prior Art section of this page." I treat that as the specification's own prior‑art discussion plus the 37–38 references in the citation table. That set is a floor, not a ceiling — a real § 103 attack is not limited to the examiner's citation list. Where the cited set is thin, I say so and identify what is missing.

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1. The admitted‑prior‑art baseline is unusually powerful here

The single most important fact for a § 103 analysis of this patent is that the applicant drew, described, and submitted its own closest prior art — the FIG. 1 "MAGNETITE" system (Viking Energy Systems Co., Hanover, Mass.) — and it is recorded as a Non‑Patent Citation: "Drawing of Prior Art Storm Window Known to Applicants." Statements about the prior art in a specification are admissions usable against the applicant, both as evidence of the state of the art and as a source of motivation to modify.

Mapping FIG. 1 (as described in the specification itself) to claim 1:

Consequence: only two limitations distinguish claim 1 from the applicant's own admitted art — (i) the non‑adhesive mounting of the frame‑side element, and (ii) the rigidized hollow member. Every other element of independent claim 1 is expressly conceded as old. That is an exceptionally narrow gap for a "pioneering" framing.

Equally important, the specification supplies its own motivations:

• Adhesives "used to attach the steel element (28) to the frame (22)" fail at about 175 °F and "tend to soften and grow weak" at 150 °F because the air chamber (42) "can reach a temperature of up to 160° F."
• The steel element "tends to expand less and at a different rate than the polymeric adhesive and carrier, e.g. PVC based tape. This stresses the adhesive bond."
• Heated panel and retaining member "tend to become soft and pliable," the sheet "sag[s] due to its own weight," breaking the magnetic and/or adhesive bond — "a safety hazard."
• Magnetic elements "must make flush contact," yet "[m]ost windows are not perfectly square" (ridges, bumps, tapers, slants; settling, warpage, wear).

An applicant who writes those four paragraphs has written the motivation‑to‑combine section of the Office action for the examiner.

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2. What each cited reference contributes

Grounded in the reference texts (verified where noted; title‑only entries flagged):

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3. Claim‑by‑claim § 103 combinations

Claim 1 (system) — vulnerable

Primary combination: Admitted FIG. 1 art (MAGNETITE) + Foreman (US 3,133,324) + Gorham (US 4,079,558).

• Admitted art supplies everything but the two deltas (table above).
• Delta (i) — non‑adhesive mounting of the frame‑side element: Foreman expressly discloses two alternative mountings for a magnetic strip, adhesive or "a pressed fit in a groove or slot." Selecting the pressed fit is not an invention; it is the express teaching of a reference in the identical field. Gorham independently supplies non‑adhesive fastening ("flat headed screws"), and the '223 specification itself mounts its frame member by screws (221). Motivation is admitted: adhesive failure at 150–175 °F and differential thermal expansion of steel vs. PVC carrier.
• Delta (ii) — rigidized elongated hollow structural member: Gorham discloses a magnet‑carrying profile in which "the inner and outer portions are joined by a central portion which is hollow" and which has converging tapered legs that spread to grip the pane — structurally the FIG. 2/3 arrangement minus the word "rigidized."

Alternative/additional combination for delta (ii): Anderson (US 3,824,753) + Hartwig‑Hartoglass (US 4,441,290). If "rigidized" is construed to require genuine stiffness (as the applicant insisted in distinguishing Gorham), then Anderson supplies the known technique of an extruded profile with relatively hard structural portions and soft compliant portions — i.e., making the panel-edge extrusion stiff is a matter of selecting durometer, a known result‑effective variable — and Hartwig‑Hartoglass supplies both the interlocking rib retention (a "better resist forces tending to separate" teaching) and the express reinforcement object ("Straight members … to reinforce the frame member"; "rigid plastic to provide additional reinforcement"). Motivation for stiffening: the specification's own sag/failure-at-temperature admission.

Rationales: (A) combining prior art elements according to known methods to yield predictable results; (B) simple substitution of one known (mechanical) fastening for another known (adhesive) fastening; (C) use of a known technique (dual‑durometer extrusion; interlocking ribs) to improve a similar device in the same way; (D) applying a known technique to a known device ready for improvement. Same field, same problem, all elements known.

Claim 4 (system, hinged frame member) — least vulnerable independent claim

Claim 4 does not require the rigidized hollow member (that is added only by claim 5), so its novelty rests entirely on: "two legs hingedly joined to each other at substantially right angles, one leg mounted to the frame, the other carrying the first magnetic element."

Candidate combination: Admitted FIG. 1 art + Anderson (dual durometer) + Foreman (pressed‑fit magnet retention) + the specification's own out‑of‑square-frame admission.

• Motivation is strong and admitted: magnetic elements "must make flush contact" for 4–8 lb/linear ft holding force, yet "[m]ost windows are not perfectly square" due to settling, warp, taper, and wear. A POSA would plainly seek a compliant frame‑side mount.
• Anderson teaches the enabling technique — a single extruded profile with two durometer zones, one relatively hard and one relatively soft, in a storm‑sash profile.

But — honest caveat: none of the references in this cited set expressly discloses a living hinge between a frame‑mounting leg and a magnet‑carrying leg, nor the specific durometer differential applied across a hinge. Anderson's dual durometer is used for pane‑gripping barbs and sealing flanges, not as a hinge. A robust claim‑4 challenge would need additional art (living‑hinge/dual‑durometer extrusion art, or a right‑angle magnetic mounting bracket — Baermann CA 707,857 "Magnetic bracket" is in the citation table as a foreign reference and is titled suggestively, but I have not verified its disclosure). As the record stands, claim 4 is the hardest claim to invalidate, and it is also the claim most likely to survive a § 112 § written‑description/claim‑differentiation debate with claim 1 ("at substantially right angles" + "hingedly" as the point of novelty).

Claim 5 — vulnerable to the same extent as claim 1 (it simply re‑adds the rigidized member to claim 4).

Claims 2 and 3 — vulnerable

Right‑angle two‑leg frame geometry is a routine mechanical arrangement (mounting face + magnet face). Claim 3's hinge limitation is the claim‑4 hinge, so its vulnerability tracks claim 4 — again, weak in the cited set.

Claims 6, 7, 13, 16 — highly vulnerable

Material selections: acrylic panel (claim 6); PVC or ABS for frame/retaining member (claims 7, 13, 16). All are routine design choices among known materials with predictable properties for extruded window profiles; the specification itself names PVC, polypropylene, nylon, acrylic and styrofoam without asserting any criticality. KSR squarely covers "obvious to try" material selection with no unexpected result.

Claims 8, 10, 17 — vulnerable

First magnetic element retained between two projecting lips on the leg. Foreman's pressed‑fit‑in‑a‑groove is the express teaching; additive‑manufacturing/extrusion practice makes the lip pair the natural groove structure. Claim 10/17's "extruded, slidably mountable" adds only the conventional manufacturing method for such a strip — and the specification makes slidability a mere assembly convenience, not a technical effect.

Claims 9, 11 — vulnerable

Second magnetic element and inner leg each having interlocking projecting lips. Hartwig‑Hartoglass discloses exactly this retention principle (complementary interengaging ribs resisting separation) and is motivated for the same reason (resist separating forces, add reinforcement). The admitted FIG. 1 art already mechanically mounts the second magnetic element to the inner leg, so only the interlock geometry is new — pure configuration.

Claim 12 (panel retaining member per se) — moderately vulnerable; the most defensible of the independent claims, but still weak

Combination: Admitted FIG. 1 art + Hartwig‑Hartoglass (interlocking rib retention) + Owen (U‑shaped cross‑section annular frame about the pane) [+ Gorham for the hollow edge profile].

Element mapping:

• Outer/inner legs joined at one end gripping the edge → admitted FIG. 1 art (and Gorham's converging spreading legs).
• Inner leg with a pair of spaced projecting lips diverging from one another, defining spaced retaining channels on their outer sides → Hartwig‑Hartoglass's channel ribs/groove geometry; Foreman's groove.
• Elongated magnetic element of U‑shaped cross‑section with a contact wall and a pair of converging lips → Owen's "annular frame of metal of substantially U‑shaped cross section"; the FIG. 1 admitted magnet strip is itself an extruded element mounted in the leg.
• Interlock forming the rigidized hollow member → Gorham (hollow central portion at the panel edge) + Anderson/Hartwig rigidity teachings.
• Contact wall positioned outwardly beyond the inner leg and its lips → a positional consequence of the interlock, with no separate technical effect asserted in the specification and no functional consequence identified. Under KSR, a mere change in location/arrangement of a known element that yields no new result is not patentably distinguishing. This is the weakest limitation in claim 12.

The strength of claim 12 lies in the specific hook geometry (diverging channels + converging hooks + outer contact wall) — a challenger must produce art with a fairly close interlocking mirror‑image profile, or rely on the "obvious to try" combination of Owen's U + Hartwig's ribs. This is a contestable, but not impregnable, claim.

Claims 14, 18 — follow their parents; claim 18's optical/durometer values

Claim 18's narrowing to hinge A‑60 to A‑68 and legs D‑75 to D‑81 is the classic In re Aller / In re Boesch situation: reciting a narrower range within a disclosed broad range (Anderson's "relatively hard" / "relatively soft") where the specification reports no comparative data and asserts no criticality or unexpected result. Absent evidence of a result‑effective variable with unexpected results, the narrowed range is prima facie obvious as routine optimization. If ever challenged, Applicant/patentee would need the Aller rebuttal (new and unexpected results at the criticality) — which the record does not contain.

Claim 15 (frame member per se) — vulnerable on the magnet‑mounting limitation, defensible on the hinge

• "A magnetic element mounted to the second leg by two retaining lips projecting from the second leg along the length thereof between which the magnetic element is retained" → Foreman's pressed fit in a groove, verbatim in substance.
• "Hinge means joining the first and second legs so the legs normally extend at a right angle … for permitting the legs to move relative to each other, the hinge means has a durometer hardness of about A‑60 to A‑72 and the legs have a durometer hardness greater than D‑70 (shore)" → this is where the claim lives. Anderson supplies the dual‑durometer extrusion concept but not the hinge; the cited record contains no reference expressly disclosing a soft‑hinge/hard‑leg dual‑durometer frame member. I therefore cannot assert that this limitation is met by the cited set. It may well be met by ordinary living‑hinge extrusion knowledge (a mature technology at the 1983 filing date) or by art outside the citation list, but I should not represent that as verified.

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4. Motivation‑to‑combine synthesis

Collapsing the above into the rationales a challenger would actually plead — note that five of the six come from the patent's own text:

All references are analogous art in the strict sense: storm sashes, secondary/interior glazing, and magnetic window fasteners — the very field of the invention and the field of the inventor's stated problem. That collapses any "non‑analogous art" defense and supplies the KSR "predictable variation of a known device in the same field" rationale for essentially every claim element.

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5. Where the obviousness case is weak (and what a patentee would argue)

1. Teaching away via Gorham. The applicant affirmatively argued that Gorham's hollow central cavity "provides no rigidity for the pane material and the magnetic materials force is dissipated by the material which forms the central cavity and causes slippage between the surface and strip." Gorham's cavity is deliberately resilient "to compensate for irregularities." A patentee can argue Gorham teaches the opposite of a rigidized member — especially if "rigidized" is construed to require the interlocked, stiffened beam. Rebuttal: Anderson and Hartwig‑Hartoglass supply the missing rigidity teaching and the motivation (sag), so Gorham need not be modified in the direction it disfavors; it need only be combined, not altered.
2. Claim 4's hinge is not in the cited set. As discussed, the two‑leg hinged right‑angle frame member with a defined durometer differential is the strongest non‑obviousness position. A challenge limited to the examiner‑cited references will likely fail here.
3. Claim 12's specific hook profile. The mirror‑image diverging/converging lip geometry is specific enough that a challenger needs close art (Hartwig‑Hartoglass is suggestive but not identical — its ribs are linear channel/flange ribs, not hooks extending into outer‑side channels).
4. Secondary considerations are essentially absent from the record. The specification contains only attorney‑style statements of advantage ("neat in appearance," "excellent thermal insulation ability," "without sagging"). There is no evidence of commercial success, long‑felt need, failure of others, copying, or industry praise in the record I can verify — and because the patent never appears to have been litigated (per the earlier sections), there is no nexus record either. Any patentee argument on secondary considerations would have to be built from scratch.
5. Claim 18's narrow ranges are the one place where the patentee has a doctrinal hook (Aller rebuttal), but there is no supporting data in the specification.

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6. Bottom line

Net: Independent claims 1, 12, and 15 are all exposed, but on different footings — claim 1 through the applicant's own admissions plus Foreman/Gorham/Anderson; claim 12 through a three‑reference interlock/geometry combination; claim 15 only partially, with its hinge limitation unmet by the cited record. Claim 4 (and, derivatively, claim 3) is the hardest to invalidate on the cited art, which is an odd result for a patent whose specification treats the FIG. 1 system as the whole problem and the rigidized hollow member as the solution — it suggests the drafter deliberately wrote claim 4 to a structural feature (the hinged right‑angle frame member) that the FIG. 1 art simply does not have, and then relied on claim 1's "rigidized member" language as the real commercial differentiator. That inversion (strongest claim protecting the least‑discussed feature; weakest claim carrying the asserted inventive concept) is the single most useful takeaway for anyone assessing this patent's validity.

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Confidence and provenance

• Verified against reference texts: Gorham (US 4,079,558), Anderson (US 3,824,753), Hartwig‑Hartoglass (US 4,441,290), Gingle (US 4,194,331) — quoted above from the patent PDFs/Google Patents.
• Taken from the '223 specification's own prior‑art discussion (authoritative for this analysis): Owen, Foreman, Gorham, Anderson, Peterson III, Gingle, and the FIG. 1 MAGNETITE system.
• Title‑only, not characterized: US 4,391,137 (Baxt), US 4,387,541 (Boomershine), US 4,409,758 (Plaskolite), US 4,409,709 (Titanseal), US 4,452,020 (Seal Tite), CA 707,857 (Baermann), and the remaining 1970s storm‑window/molding references. I have not verified their disclosures and deliberately refrain from asserting what they teach. Several are plausibly highly material to claims 1, 8, and 15 (particularly Baxt's "Plastic panel mounting frame" and Plaskolite's "Perimeter strip for magnetically attractable extruded plastic window system"), and a real challenge should retrieve and read them.
• Not verified / flagged rather than corrected: the specification's spelling "barrium ferrite" (i.e., barium ferrite) is reproduced literally; the "acrylonitrile (ABS)" recitation in claim 16 vs. "acrylonitrile‑butadiene‑styrene (ABS)" in the specification is carried forward as noted in the earlier claim analysis; and the Defender brochure's "U.S. Patent 4,461,223" (vs. 4,561,223) remains unresolved per the earlier assignment section. None of these affects the § 103 analysis.
• No material contradiction with the previously generated sections. The earlier sections' null results on litigation, PTAB, and downstream assignment transfers are consistent with — and in fact reinforce — the practical posture here: this is an untested, never‑litigated 1985 claim set whose validity is now a purely academic question.