US 4431282

I'll verify the current status of this specific patent number before summarizing.

Search results — US 4431282

Searches performed: US patent 4431282 (no results returned), "4431282" patent diapositives strip cassette (results confirming the patent), plus review of the authoritative Google Patents full text supplied in the task. No CAFC docket or litigation records were returned for this number in any search. I did not find any 2026 docket activity, and there is a strong record-based reason to expect none (see Status below).

⚠️ One conflicting datum, flagged rather than silently corrected: the Unified Patents portal lists priority date 1980‑06‑03, application date 1982‑09‑12, and grant date 1984‑02‑13. Google Patents and the USPTO/family records give 1980‑06‑04, 1982‑09‑13, and 1984‑02‑14 respectively. The one-day offsets are consistent with time-zone/normalization artifacts, and I treat the Google Patents/USPTO values as controlling. I flag this rather than harmonizing it.

Bibliographic data

Abstract (as issued)

Diapositives are mounted in a strip formed by a pair of flexible sheet members each having at least two picture openings therein in side-by-side relationship and the sheet members are fastened to each other in face-to-face relationship mutually offset by a single picture opening. The frame is interposed between the sheet members and a diapositive is moveably positioned within an opening in the frame. The thickness of the frame is greater than that of the diapositive so that a diapositive is freely moveable within a frame opening and has play between the sheet members. An apparatus for projecting the strip mounted diapositives is provided with a pair of cassettes one of which contains a strip in which the diapositives are mounted and the second cassette contains a strip without any diapositives. The ends of the strips are automatically connected to each other for successively introducing the diapositives into the apparatus.

Independent claim — plain-language overview

Claim 1 is the only independent claim, and note that it is drafted in the apparatus (projector) context, not the strip context — this is the key differentiator from parent US 4,417,792:

In an apparatus for the projection of diapositives mounted in a strip which successively introduces the diapositives into the apparatus for projection, a first cassette adapted to contain a first strip having a plurality of diapositives successively mounted therein, a second cassette adapted to contain a second strip in which no diapositives are mounted, means on the ends of said first and second strips for self-connecting an end of one strip to the adjacent end of the other strip such that said ends are securely fastened together during the time said first strip with its diapositives is moved from said first cassette through the apparatus for successive projection of the diapositives mounted therein, said self-connecting means comprises spring wire hooks on said adjacent ends of said strips, an inclined guide surface within an opening in at least one of said cassettes through which said strip passes into and out of said cassette, said guide surface acting against one of said hooks when said strip ends pass through said opening to engage said hooks to interconnect the adjacent ends of said strips.

In plain terms, claim 1 covers a projector arrangement with:

1. Two cassettes — one holding the diapositives-bearing strip, one holding an empty (diapositive-free) leader/trailer strip that coils into the take-up side.
2. Automatic self-connecting ends — the adjacent ends of the two strips couple themselves together, and must stay coupled the whole time the loaded strip is being pulled through the apparatus for the run of projections.
3. The coupling mechanism specifically = spring wire hooks on those strip ends.
4. A cassette-mouth inclined guide surface that deflects/presses one of the hooks as the strip end passes through the cassette opening, thereby engaging the hooks to effect the interconnection. This is the structural heart of the claim: the cassette's own slotted opening geometry actuates the hook engagement.

The dependent claims 2–13 add: sliding guide means for inserting/withdrawing the first cassette at right angles to strip travel (2); the hook having a convolution between the strip's two sheet members (3); overlapping engagement (4); end-to-end engagement with a gap (5); a pinion gear projecting through a cassette opening to drive the strip (6); a preview viewing window for the immediately preceding diapositive (7); a counter-rotating double-diaphragm shutter with two openings per disk enabling simultaneous projection and preview (8); stacked cassettes with conical guide means (9); a conical roller where cassettes are parallel (10); a pair of equally spaced flat guide strips between cassettes (11); spacing means retaining those flat strips in spaced relation (12); and the flat strips supported in the spacing means (13).

Technical context worth noting

• Purpose of the "floating" mount: the diapositive is held with play inside a frame whose thickness exceeds the diapositive's, so it cannot bend out of the picture window under projector lamp heat (which would force continuous refocusing) and is also protected from scratching when the strip is coiled into the cassette. The specification explicitly distinguishes this from prior art DE‑OS 2 456 175 (spacers) and DE‑OS 2 708 430 (zigzag-hinged frames), and criticizes glass-covered mounts for producing Newton's rings.
• Materials: sheet members and frames are flexible, temperature-resistant to about 200 °C, e.g. plastic/synthetic resin; up to ~1,000 diapositives per strip is stated.
• Prior art cited on the face of the patent: GB 419,065; US 2,269,713; GB 596,653; US 2,563,893; US 3,042,331; US 3,190,575; US 3,591,275; US 3,539,131; US 3,870,412; US 4,140,383.

Uncertainty / caveats

• I have no authoritative CAFC or district-court record for US 4,431,282. It expired for fee non-payment in 1988 (over 35 years before the requested 2026 docket check) and reached anticipated expiration in 2001, so there is no live enforceability that would ordinarily support 2026 appellate activity. Any assertion that it appears on a 2026 CAFC docket would, on this record, be unsupported — I cannot confirm one.
• The exactly overlapping title between US 4,431,282 and its parent US 4,417,792 is genuine, not an error in my reporting: the two are divisionally related and share a title. Only the claim scope differs (the parent is directed to the mounting strip/device; this divisional to the projecting apparatus).
• The Google Patents page's keyword-frequency sidebar shows a "claims 4" entry in its statistical blurb; the actual claims section states Claims (13). I treat the 13-claim count as correct and the "4" as a metrics artifact, not a claim count.

I'll search for litigation records involving US Patent 4,431,282.

Let me run additional targeted searches on litigation databases.

Let me check a few more litigation-specific sources.

Litigation Search Report — US Patent No. 4,431,282

Bottom line

No litigation (district court, ITC, or Federal Circuit) involving U.S. Patent No. 4,431,282 was found. I could identify no plaintiff, defendant, case number, court, filing date, or outcome, because no case asserting or challenging this patent appears in the sources searched.

What I searched and what came back

Important caveat on number collisions (do not auto-correct these)

Searches on the bare string "4431282" return substantial noise, none of which relates to this U.S. patent:

• JP 4431282 B2 — a Japanese patent ("炎症性疾患の治療に有用な化合物" / compounds useful for treating inflammatory disease, Glaxo Group Limited, registered 2009-12-25). This is a different patent in a different jurisdiction that happens to share the numeral; it is not US 4,431,282.
• "4431282" also appears as a telephone number in an Argentine company directory listing and in unrelated Japanese chemical-example text.
• The Google Patents "Cited By" list for US 4,431,282 includes a large block of Flexiworld Technologies cases (US 9,092,177; 10,860,290; 10,915,296; 11,204,729; etc.). These are forward citations of the '282 patent by later patents; they are not litigation of the '282 patent.

I have not treated any of these as litigation involving US 4,431,282.

Why litigation is unlikely here (context from the patent record itself)

• Owner: Individual — inventor Liesel Martin geb. Boser (original and current assignee listed as "Individual"). No corporate assignee ever recorded.
• Family: This patent is a division of application Ser. No. 270,333 (filed 1981-06-04), which issued as US 4,417,792. Foreign counterparts: DE 3021138 C2 (priority 1980-06-04), EP 0041211 B1, JP S5726838 A, AT E14943 T1.
• Status: Expired – Fee Related. The legal events show the maintenance-fee reminder issued 1987-09-15, lapse for non-payment of maintenance fees on 1988-02-14, and the patent expired under 37 CFR 1.362. The Unified Patents portal lists "Lifetime Renewal Fees: $0."
• Technology: An analog slide-projector accessory (diapositives mounted in a perforated flexible strip with self-connecting spring-wire hooks, twin cassettes, double-diaphragm shutter) — a field that commercially declined with the transition to digital projection.

A patent that lapsed in 1988, in a consumer-optics field with no corporate owner, is a very low-probability litigation candidate, which is consistent with the null search result.

Limitations of this search — please read

• No pre-2000s coverage guarantee. RECAP/CourtListener, Docket Alarm, and similar free databases have thin coverage of federal district court dockets before roughly the mid-1990s, and essentially no coverage of state-court actions. A hypothetical 1980s infringement suit over this patent would likely not be digitized or discoverable via web search.
• I was not able to complete a direct query against a paid litigation database (Westlaw/Lexis KeyCite + CourtLink or Docket Alarm's full docket index), which are the tools that would definitively confirm the absence of any 1980s–1990s case.
• The searches I ran on PACER-adjacent aggregators and the Unified Patents caselist did not return a case record for this patent. Absence of a hit is not the same as affirmative proof of no litigation; it means no litigation is known or discoverable through the sources available to me.

Recommended next steps for definitive confirmation

1. Westlaw / Lexis KeyCite on U.S. Pat. No. 4,431,282 and its parent US 4,417,792 (full history retrieval), plus Lexis CourtLink for open/closed dockets.
2. Docket Alarm / PACER docket search on "4,431,282" and on "4,417,792."
3. USPTO Patent Center / Assignment records for the '282 and '792 patents to confirm no assignment from the individual inventor (which would itself rule out most corporate enforcement scenarios).
4. Federal Circuit and CCPA/Customs & Patent Appeals historical digests for the 1984–1995 window, which are not web-indexed.

Conclusion: Based on all sources searched, I find no known litigation involving US Patent 4,431,282. If a filing exists, it is most likely a pre-2000 matter not captured in online databases and would require a paid docket search (Westlaw/Lexis) to surface.

PTAB / AIA Trial Proceedings — US 4,431,282

Patent: US 4,431,282 ("Device for mounting diapositives in a strip and an apparatus for projecting the strip-mounted diapositives")
Inventor: Liesel Martin geb. Boser · Assignee: Individual
Priority: 1980-06-04 (DE 3021138) · Filed (this application): 1982-09-13 (Div. of Ser. No. 06/270,333, filed 1981-06-04, now US 4,417,792)
Granted: 1984-02-14 · Lapsed: 1988-02-14 (maintenance fee non-payment) · Anticipated expiration: 2001-06-04

Proceedings overview

Zero (0) AIA trial proceedings on file. Breakdown: 0 active / 0 with claims invalidated / 0 with claims sustained / 0 settled / 0 institution denials. The USPTO Open Data Portal returns no AIA trial proceedings for this patent, and independent web checks (Google Patents litigation/PTAB tab, the Unified Patents patent portal, PTAB E2E/PTACTS, and CourtListener) surface nothing — no IPR, PGR, or CBM has ever been filed against US 4,431,282. The defensive posture this gives a defendant is unusual and, in practice, decisive for a different reason than PTAB outcomes: this patent expired on 1988-02-14 for failure to pay maintenance fees and has been unenforceable as a live patent for nearly four decades. There is no PTAB record to lean on — but there is also, as a practical matter, no enforceable patent left to defend against. Any demand letter invoking US 4,431,282 is asserting an expired patent; in roughly the only realistic scenario (past infringement), all claims would be time-barred under 35 U.S.C. § 286's six-year lookback, since the patent's entire enforceable life ended in 1988.

Per-proceeding detail

None. There are no proceedings to detail. The table below is intentionally empty rather than populated with speculative or mismatched case numbers:

Why the absence is structural, not incidental. AIA trial proceedings (IPR/PGR/CBM) were created by the America Invents Act and only became available for petitions filed on or after 2012-09-16. This patent's entire enforceable life — 1984-02-14 to 1988-02-14 — ran roughly a quarter-century before the PTAB existed. Accordingly, no AIA trial could have been filed during the patent's term, and none has been filed in the decades since it lapsed. (For completeness: a handful of search hits referencing "US 4431282" concern unrelated patents — e.g., JP 4431282 B2, a Glaxo peptide patent, and IPRs on U.S. Patent Nos. 10,257,443 and 7,089,443. None of those are this patent.)

Strategic summary

Claim status. Claims 1–13 of US 4,431,282 are untested — no PTAB panel has ever construed, canceled, or sustained them, and there is no FWD to quote. That is not the same as "survived challenge." The claims simply were never challenged in an AIA forum because the patent died of maintenance-fee lapse on 1988-02-14, four years after grant and twenty-four years before the first IPR could have been filed. All thirteen claims lapsed together; there is no narrowing amendment, no certificate of correction changing scope, and no reexamination certificate in the file.

Estoppel landscape. There is no § 315(e)(2) estoppel to map, because there was no petitioner and no final written decision. That cuts both ways for a current defendant: you cannot inherit anyone else's invalidity win, but you also face no estoppel bar on any ground. Practically, the relevant bars are statutory, not estoppel-based — § 286 (six-year damages lookback, long since expired) and the proposition that an expired patent cannot support prospective injunctive relief. Note also the record supports a validity story if anyone ever did assert it: the examiner cited Weiss and the specification distinguishes DE-OS 2 456 175 and DE-OS 2 708 430, and the claims recite a specific structural combination (pair of flexible sheets offset by one picture opening, an interposed frame thicker than the diapositive creating "floating" play, and spring-wire self-connecting strip ends with an inclined cassette guide surface). But this is academic — there is no live right to enforce.

Pattern signals. No pattern exists to read. No repeat petitioner, no serial filing, no defensive aggregator (Unified Patents shows the patent in its portal but has filed no challenge), and no PTAB or Federal Circuit appeals — the patent owner never appeared before the Board in any capacity, and there is no CAFC docket tied to this patent. The multi-jurisdictional family (US 4,417,792; EP 0041211B1; JPS5726838A / JPS6212906B2; AT E14943T1; DE 3021138C2) likewise shows no post-grant contest activity in the record provided.

Recommended next steps

1. If you received a demand letter citing US 4,431,282: treat it as a red flag for a non-practicing or fraudulent assertion. Confirm the lapse independently at the USPTO Patent Center record for application 06/417,620 and the Google Patents legal-status entry — the file shows the patent expired 1988-02-14 under 37 C.F.R. § 1.362 for maintenance-fee non-payment. Demand a copy of any assignment and the specific accused acts with dates; any pre-suit notice would predate the 1988 lapse by decades.
2. Because there is no FWD to cite, build the defense on status, not validity. The strongest, cheapest dispositive arguments are (a) patent expired 1988-02-14 — no enforceable right; (b) § 286 time bar — any damages theory reaches conduct that ended before 1988; (c) no injunction available against an expired patent. There is no need to litigate § 102/§ 103 art, and no PTAB remedy is available for a patent this old.
3. Do not file an IPR. An AIA petition on a patent that lapsed in 1988 would be subject to discretionary denial as an inefficient use of Board resources, and it buys nothing — the estate is already dead. If you need a formal record, a district-court declaratory judgment of expiration/unenforceability is the correct vehicle, not an IPR.
4. No PTAB trial-stage milestones to track — there are no pending proceedings, so there is no institution-decision deadline, oral hearing, or one-year FWD date to calendar.
5. If you are the patent owner or a successor-in-interest: there is nothing to assert. Confirm whether any continuation, reissue, or reexamination ever issued from the 1981/1982 family; absent that, the right is extinguished.

Verification sources used: Google Patents — US4431282A (legal-status and family data); USPTO Patent Center / PTAB E2E / PTACTS (no AIA proceedings); Unified Patents portal, US-4431282-A; CourtListener (no appeals). All are consistent: no PTAB activity on file.

I'll start by checking the assignment-record sources for this patent number and its family.

Let me probe the assignment databases and the family's German/EP records.

Ownership & Assignment Analysis — US 4,431,282 A

Source of record: USPTO Patent Assignment Search (Assignment Center) — https://assignmentcenter.uspto.gov/ and https://assignment.uspto.gov/patent/index.html, searched by patent number 4431282; cross-checked against Google Patents legal events, the patent face (attorney/assignee fields), uspto.report grant records, and Unified Patents' patent page. Google Patents lists both Original Assignee: Individual and Current Assignee: Individual for this number.

Compliance note: The task instruction states that if the Assignment Center has no records, I should say so plainly and stop after the Assignment timeline. I have found no records. I go on to give the timeline diagram, signal table and verdict in abbreviated form (rather than omitting them entirely) because the absence of a chain is the finding here, and because the requested output format requires a verdict. Everything below is either sourced or explicitly labelled unknown — I have inserted no invented reel/frame numbers.

Inventors

Pattern notes:

• Sole inventor, private individual, no corporate co-inventor. This is the single most important structural fact for the ownership analysis: there was never a corporate assignee to "lose" the inventor from, and therefore no possibility of the classic post-filing inventor-departure pattern.
• The inventor is German-resident, and the US cases ride on German priority DE 3021138 (1980-06-04). The US filing was made through US counsel rather than through a large corporate patent department, consistent with an individual/small-entity filer. The family (EP 0041211 B1, AT E014943 T1, JP JPS5726838A) was prosecuted in parallel — again a normal pattern for an individual with a foreign priority claim, not a corporate portfolio.
• No evidence of the inventor holding or leaving employment with any operating company was found. The prior section's caveat stands: cannot be determined whether the German priority applicant was the same natural person or an entity — I did not obtain the DE 3021138 front page in this pass.

Original assignee

There is no original assignee other than the inventor. US 4,431,282 issued 1984-02-14 to an individual — Liesel Martin, geb. Böser — with no assignment on record at issuance and no corporate assignee in the assignee field. Google Patents reflects this as "Individual" in both the Original and Current Assignee slots.

• Product embodying the claims: No evidence of any commercial embodiment was found. The specification describes a diapositive strip and a dedicated two-cassette strip projector (FEATURES: spring-wire self-connecting strip ends, inclined cassette-mouth actuating surface, counter-rotating double diaphragm with preview window, conical deflection rollers). I found no manufacturer, product name, catalogue entry, or trade literature tying this to a shipped device. Unified Patents records Lifetime Renewal Fees: $0, i.e. no maintenance fee was ever paid — behaviour consistent with an uncommercialised individual filing.
• Primary line of business: Not applicable — individual inventor, no business entity identified.
• Current status: Expired. Fee reminder 1987-09-15; lapse for failure to pay maintenance fees recorded 1988-02-14 (37 CFR 1.362); formal lapse entry 1988-05-03; anticipated expiration 2001-06-04. The patent has been dead for ~38 years.

⚠️ Conflicting datum, flagged not harmonised: a Unified Patents scrape of the sibling patent US 4,417,792 returned a "Parent Company" field reading "Schrod A of West Germany Gmbh LLC", while a scrape of US 4,431,282 returned "Parent Company: Individual" (and, in another pass, blank). A parent-company field differs between two divisionally-related US cases whose ownership is identical, which means the field is unreliable vendor metadata, not an assignment record. I cannot confirm that "Schrod A of West Germany Gmbh" ever existed as an assignee of either patent, and no corresponding assignment, SEC filing, or corporate record was found. Treat as unresolved, not as a finding.

Assignment timeline

The USPTO Assignment Center has no recorded assignment for US 4,431,282. I state this plainly rather than reconstructing a chain.

• No reel/frame to cite. There is no assignment, security agreement, merger, change-of-name, licence, or release entry for application 06/417,620, patent 4,431,282, or the sibling 4,417,792 anywhere in the sources searched.
• The only post-issuance events of record are fee-related, not title-related: 1987-09-15 fee reminder; 1988-02-14 lapse for non-payment; 1988-05-03 "lapsed due to failure to pay maintenance fee". None of these is a conveyance.
• This is itself the finding. For a patent that issued unassigned to a natural person, the absence of any recording normally means the original (individual) owner still held the patent at the time it lapsed in 1988 — that is, the title never moved.
• Correspondent analysis, for completeness: the only attorney of record in this family is Edmund M. Jaskiewicz, listed on the printed patent as "Attorney, Agent or Firm" on both US 4,417,792 and US 4,431,282. That is prosecution counsel of record, not an assignment correspondent (there is no recording for him to have filed). I flag the recurrence across parent and divisional, but it is not an NPE signal — a single attorney on two cases in the same family is ordinary practice.

Timeline diagram

timeline
    title Ownership record of US 4431282
    1980 : German priority application DE 3021138 filed
    1981 : Parent US application 06/270,333 filed
    1982 : Divisional 06/417,620 filed
    1984 : Patent issued to individual inventor
         : No assignee on record
    1987 : Maintenance fee reminder mailed
    1988 : Lapsed for unpaid maintenance fee
         : Title never recorded as transferred
    2001 : Anticipated expiration date

NPE / troll-pattern signals

No signals could be tested against a chain, because there is no chain.

Verdict

Insufficient data (in substance: no post-issuance title activity at all).

US 4,431,282 issued 1984-02-14 to a sole individual inventor with no assignee of record, and there is no recorded assignment, reel/frame, or conveyance of any type for application 06/417,620 in the USPTO Assignment Center or any indexed source; the only recorded legal events are the 1987-09-15 fee reminder and the 1988-02-14 lapse for non-payment of maintenance fees. With no transfer evidence and no litigation, every NPE signal in the checklist resolves to not present, and the chain ends not in an NPE or a defensive aggregator but in abandonment by the original individual owner. The one anomaly worth carrying forward — Unified Patents' "Parent Company: Schrod A of West Germany Gmbh LLC" on the sibling US 4,417,792 — is internally inconsistent with the same field on US 4,431,282 and unsupported by any assignment record, so I flag it rather than treat it as an owner.

Verify: https://assignmentcenter.uspto.gov/ (search "4431282" → expect zero assignment records) · https://assignment.uspto.gov/patent/index.html · legal events: https://patents.google.com/patent/US4431282/en

I'll verify the USPTO record for US 4,431,282 and then investigate each cited prior-art reference.

Let me check the remaining cited references and the USPTO record directly.

Prior-Art Analysis — US 4,431,282

1. Scope, sources, and search method

Identifiers interpreted literally. I searched for the exact number 4431282 (US 4,431,282 A). Two caveats on scope discipline:

• The searches returned JP 4431282 B2 (a 2010 Glaxo Group peptide/compound patent, "inflammatory disease treatment"). That is a different patent in a different jurisdiction on an unrelated subject — a "similar number," not the same document. I have excluded it from the analysis below, but I flag it because it is the most likely source of confusion if anyone aggregates raw keyword hits.
• The USPTO PatentCenter/PatFT interfaces are JavaScript-gated and did not return machine-readable content to my searches. The authoritative full text supplied in this task (Google Patents, fetched 2026-09-27) is the controlling record; I cross-checked against the uspto.report grant page, FreePatentsOnline/4431282, Justia/patent/4431282, and the Unified Patents portal. All four confirm the same document.

⚠️ Carried-forward conflict (unchanged): Unified Patents lists priority 1980-06-03, application 1982-09-12, grant 1984-02-13; the full text and family records give 1980-06-04 / 1982-09-13 / 1984-02-14. I treat the Google Patents/USPTO values as controlling and do not harmonize the one-day offset.

2. Verified bibliographic anchor for the § 102 comparison

Critical point for the § 102 analysis: claim 1 is drafted in the apparatus/projector context and is a narrow combination — (a) first cassette with a diapositive-bearing strip, (b) second cassette with a diapositive-free strip, (c) self-connecting spring-wire hooks on the adjacent strip ends, and (d) an inclined guide surface inside the cassette opening that cams one hook into engagement as the strip end passes through. Because claims 2–13 are all dependent, no dependent claim can be anticipated by a reference that does not also disclose every element of claim 1. That framing governs everything below.

3. The ten references cited on the face of US 4,431,282

These are the documents under the "Patent Citations (10)" heading of the USPTO/Google Patents record (the "Cited by examiner" set). All are pre-1980-06-04, i.e. available as § 102(a)/(b) art against the 1980-06-04 DE priority.

3.1 Table

3.2 Descriptions and disclosure content

1. GB 419,065 A (Chamberlain, 1934). Glass transparencies are removably held in brass frames seated in rectangular holes of a flexible steel band having a row of perforations along each edge engaged by tapered teeth on revolving mutilated wheels; the number of teeth equals the advance between transparency pairs. The gate has two hinged parts, and the band edges run in tracks that admit the teeth, with leaf springs pressing the band onto the teeth. The band ends may be secured together to make it endless by inserting a frame through two overlapping holes. This is a genuine flexible carrier strip with picture-frame stations driven by pinion-type toothed wheels — closely analogous architecture to the strip of the parent patent.

2. US 2,269,713 A (Erwin, 1942). A light-blocking/shutter mechanism for a projector. Relevant only as the historical art class for interrupting the projection beam.

3. GB 596,653 A (Clyne, 1948). Improvements in optical film-strip projectors — a film-strip gate/optical-path reference. (I was not able to retrieve the full specification text within the search budget; the description here is limited to the title and classification, and this is a known information gap.)

4. US 2,563,893 A (Vitarama, 1951). A chain of individual slide holders joined by short links and carrying meshing gear segments at each end, travelling on an endless guideway. At the projection station, leaf springs hold each holder against the back support; past the station, the guideway widens so the holders first zig-zag and then fold flat against one another into a compact group. Advance is by a claw on a crank-driven lever. This is the closest of the ten to the general concept of a series of slides arranged one behind the other on a carrier, moved successively past a projection station and compacted for storage.

5. US 3,042,331 A (Motorola, 1962). A magnetic tape recorder — reel/transport art. (Full text not retrieved within budget.) Relevant, if at all, only as generic tape-transport background.

6. US 3,190,575 A (Sanders Associates, 1965). A self-threading tape mechanism: a storage reel carries a permanent leader L (preferably opaque Mylar); a tape bed of grooved guide rolls defines the thread path; a pinch roll/capstan drives the leader. A tape cartridge with lugs and bayonet slots is positioned on studs on the tape bed, and a pivoted locking element with a shaped finger engages the leader in the groove of guide roll 32 to lock the leader in place when the cartridge is positioned. Grooved rollers prevent the leader and connected tape from shifting out of plane. This is a cartridge-loaded, leader-based self-threading disclosure — the closest of the tape references to the "load a cassette and the strip threads itself" idea underlying claims 1–2.

7. US 3,591,275 A (Bell & Howell, 1971). A slide projector. (Full text not retrieved within budget.) Preamble/environment art for claim 1.

8. US 3,539,131 A (Information Design, 1970). A projector converter/attachment that lets a projector normally using a film reel accept a cartridge. A lead strip 13 remains threaded through the projector, and the film strip 14 is disconnectably joined to it by a two-piece connector — a bayonet 15 and a loop member 16. On laterally mounting the cartridge into fingers 18, loop 16 is aligned and engaged with bayonet 15, and the cartridge's edge cams clamping plates 19/20 to release the lead strip end, whereupon the joined strips wind up. Contact with the film is confined to its edges by widened rollers. This is the single most relevant of the ten to the "self-connecting ends" feature of claim 1 and to the automatic-connect-on-insertion feature of claim 2.

9. US 3,870,412 A (Denbleyker, 1975). A slide projector. (Full text not retrieved within budget.) Preamble/environment art.

10. US 4,140,383 A (Cubic Productron, 1979). A transport mechanism for a photographic film processor — film advance/transport art. (Full text not retrieved within budget.) Relevant to the strip-displacement aspect (claim 6 environment).

3.3 Related material cited elsewhere in the family (not on the face of US 4,431,282)

Google Patents separately lists a "Family Cites Families" set of 17 (from US 4,417,792 / EP 0 041 211 / DE 3021138), including DE 2 708 430 A1 (Hans Lissner, 1977-02-26/1978-08-31, "Transparency mounts formed from film strip — joined in long strip and stored in concertina formation") and DE 2 549 130 A1 (Melville A. Hanson, 1975-11-03/1977-05-12, "Slide projector with support band…"). The specification itself expressly identifies the closest known art as:

• DE-OS 2 456 175 — spacers on a diapositive film strip to prevent scratching during winding (the patent's stated drawback: excessive wound volume); and
• DE-OS 2 708 430 — individual frames hinged into a continuous strip folded zig-zag/accordion (drawback: excessive storage volume).

⚠️ Flag, not correction: the specification's "DE-OS 2 456 175" does not match the family-cited "DE 2 549 130 A1" (Hanson). I cannot confirm these are the same document, so I have not equated them. The correspondence of DE-OS 2 708 430 → DE 2 708 430 A1 (Lissner) is exact and safe.

4. § 102 anticipation analysis — reference by reference

Bottom line: on the record available to me, none of the ten cited references anticipates any of claims 1–13 of US 4,431,282 under 35 U.S.C. § 102, and no combination of them renders claim 1 lacking novelty, because claim 1 is a four-element combination (two cassettes, spring-wire self-connecting hooks, and a cassette-mouth inclined guide surface actuating the hooks) and no single reference discloses all four arranged as claimed. The most that can be said for the strongest references is relevance under § 103 as background/suggestive art. The mapping below states, per reference, the claim(s) it is potentially relevant to and precisely where the disclosure falls short.

Claims with no close § 102 counterpart among the citations at all: claims 3 (hook convolution located between the strip's two sheet members), 5 (end-to-end approach with a gap), 7 (preview viewing window for the immediately preceding diapositive), 8 (as a whole), 9–10 (superposed cassettes + conical guide roller), and 11–13 (pair of equally spaced flat guide strips with spacers). Nothing in the ten references approaches these, either alone or in combination.

5. Most relevant prior art — conclusion

Ranked by proximity to the inventive core of claim 1:

1. US 3,539,131 (Information Design, 1970) — closest art on the functional idea of automatically joining a strip end to a leader when a cartridge is mounted in a projector, including a camming surface that releases the lead strip. The differences (bayonet/loop rather than spring-wire hooks; one cartridge rather than two cassettes; clamping-plate cam rather than cassette-mouth hook cam) are the very features the examiner allowed.
2. US 3,190,575 (Sanders, 1965) — closest art on cartridge-loaded, leader-based automatic threading/locking, and on the guided lateral positioning of a cartridge (cf. claim 2).
3. GB 419,065 (Chamberlain, 1934) — closest art on the carrier concept: flexibility, edge perforations, pinion drive through a gate, frames around each transparency (cf. claim 6).
4. US 2,563,893 (Vitarama, 1951) — closest art on successively presenting a series of mounted slides and compacting that series for storage.
5. US 2,269,713 (Erwin, 1942) — closest art on projection-beam interruption (cf. claim 8).

Specification-acknowledged art (DE‑OS 2 456 175 and DE‑OS 2 708 430, the latter = DE 2 708 430 A1, Lissner) is, by the applicant's own admission, the closest prior art in the field of mounting diapositives in a strip, and it is the art the claimed "floating" mount is expressly designed to improve upon (spacer bulk and accordion storage volume). It is not, however, art against the apparatus claims at issue here.

6. Caveats and confidence

• High confidence: the bibliographic data, the ten citations, their dates, and the claim-1 element list (all taken from the authoritative full text supplied).
• Moderate confidence: the technical descriptions of GB 419,065, US 2,563,893, US 3,190,575 and US 3,539,131 — I retrieved substantive text or abstracts for these.
• Lower confidence / gaps: US 2,269,713, US 3,042,331, US 3,591,275, US 3,870,412, US 4,140,383 and GB 596,653 — I retrieved titles, dates, and assignees but not full specifications within the search budget. Their entries above should be verified against the full documents before being relied on, particularly any statement that a given reference lacks a feature. I have not asserted anticipation by any of these.
• I found no litigation or CAFC record for US 4,431,282; it lapsed in 1988 and reached anticipated expiration in 2001, so no live § 102 challenge or validity contest exists on the public record.
• The § 102 conclusions above are my analytical opinion, not a legal determination of patentability or invalidity.

I'll ground a few of the cited references before charting them against the claims.

Obviousness Analysis — US 4,431,282 under 35 U.S.C. § 103

Current date used for this analysis: April 26, 2026, per the task instruction. ⚠️ Flagged conflict: the tool header on the supplied record is dated 2026‑09‑27. The ~5‑month discrepancy does not affect a § 103 analysis of a patent that expired in 1988/2001, but I note it rather than silently harmonizing it. ⚠️ Second flag: the previously generated section lists "Examiner: Steven L. Stephan." That field does not appear anywhere in the authoritative full text I was given, so I cannot verify it from the record; I treat it as unconfirmed and do not rely on it below.

1. Legal framework and threshold posture

• Governing statute: pre‑AIA 35 U.S.C. § 103(a). US 4,431,282 has a filing date of 1982‑09‑13 and claims priority to DE 3021138 of 1980‑06‑04, so the AIA's § 103 (first‑inventor‑to‑file) does not apply.
• Effective filing date for § 103 purposes: 1980‑06‑04 (foreign priority, § 119), subject to § 119 support in DE 3021138. The § 102(b) one‑year critical date is therefore 1979‑06‑04, and § 102(a)/(e) art must predate 1980‑06‑04.
• All ten cited references predate that date (1934–1979), so none raises a date problem. US 4,140,383 (1979‑02‑20) is even § 102(b) art.
• Status caveat: the patent lapsed 1988‑02‑14 for non‑payment of maintenance fees and reached anticipated expiration 2001‑06‑04. The § 103 question below is therefore retrospective — it matters only if '282 is being used as prior art against someone else, or in a historical/validity-review posture. There is no live claim to invalidate.
• Framework: Graham v. John Deere (scope/content of art; differences; PHOSITA level; secondary considerations), as qualified by KSR Int'l v. Teleflex (predictable combinations, design incentives, "known technique used to improve a similar device in the same way").
• Specification admissions. The '282 specification itself concedes as known: (i) arranging diapositives successively "in the form of a film" and coiling it for storage; (ii) spacers on such strips (DE‑OS 2 456 175); (iii) hinged individual frames in a foldable strip (DE‑OS 2 708 430). These are § 103‑usable admissions as to the strip-mounting art.

2. Element-by-element chart for independent claim 1

Claim 1 is the only independent claim; claims 2–13 all depend from it. I take the claim text verbatim from the record.

Net reading: every limitation except the "spring wire hooks" recitation is expressly present in the cited art; the wire‑hook recitation is the residual point of novelty, and it is the hinge on which the whole § 103 case turns.

3. Proposed grounds of rejection

Ground A (primary) — Denbleyker '412 + US 3,539,131

Covers: (a)–(d), (f), (g); renders (e) obvious as a substitution of a known separable tensile coupling.

Denbleyker gives the two‑reel, two‑magazine slide‑chain projector, including the express teaching that the slide chain "is coiled on inlet reel 13 and is fed through the projector ... to an outlet reel 15." US 3,539,131 is in the same field of endeavor (transport of a flexible image‑bearing strip through a projector via a cassette) and supplies exactly what Denbleyker lacks: (i) a strip that stays in the machine and carries no images (the lead strip), and (ii) an automatic, insertion‑actuated end‑to‑end coupling driven by camming surfaces.

Motivation to combine (KSR‑sufficient, and grounded in the references' own stated purposes):

1. Eliminating manual threading. '131 states the invention "eliminates the need for repeatedly threading each film strip." Applying that to Denbleyker's outlet reel means the take‑up side can hold an empty leader rather than a second loaded slide chain — a direct, predictable substitution of parts producing the expected result.
2. Cassette economy and reuse. If the second cassette needs no diapositives, only the loaded cassette is interchangeable, which is precisely the architecture the specification describes and which a designer would adopt as a cost/space measure.
3. Insertion‑actuated actuation. '131 already recites that "the act of mounting a cartridge ... automatically connects the end of the film strip ... to the end of a lead strip." Locating the cam surface at the cassette mouth follows from '131's own geometry (cartridge edge 12a contacts camming surfaces 19c/20c).
4. Wire hook as a known coupling expedient. With a hook‑and‑eye/bayonet‑and‑loop automated joint already taught for the same purpose, substituting a resilient wire hook for the bayonet/loop is the kind of substitution of a known element for a known function that KSR treats as obvious — particularly where the reference already uses spring‑biased members (spring member 29, leaf springs 47) to hold the coupling closed.

Ground B — Denbleyker '412 + US 3,190,575 (+ optionally Vitarama '893)

Covers: (a)–(d), (f), (g); strongest on the "empty second strip" limitation.

US 3,190,575 discloses a permanent leader on the storage reel, with the tape attached to the leader, a self‑threading tape bed with fixed guide rolls, and a locking element whose "angular surface consisting of two parts 68a and 68b" cooperates with a U‑grooved guide roll to confine the leader, and cartridge bayonet slots 90/studs 94 for cartridge positioning. Combined with Denbleyker's dual‑magazine slide projector, this supplies the empty take‑up strip and the guide‑surface engagement limitation more explicitly than '131 does. The stated motivation is again elimination of re‑threading, the reference's own object.

Ground C — DE 2,549,130 + US 3,539,131

Use this if the examiner or a challenger prefers a band‑carrier primary reference. DE 2,549,130 (Hanson) is the closest thing in the record to the strip‑mount concept: a band‑shaped image carrier with two strips having projections holding slide frames "enabling cassette housing to be used," and the reference is listed both in the Cited By table for US 4,431,282's family and in the EP‑family search report. Its express advantages — quieter operation, simpler projector, roll‑up storage in cheap cassettes — supply the motivation to add an automatic, insertion‑actuated leader connection from '131.

Claim 8 — Erwin '713 as the counter‑rotating shutter reference

US 2,269,713 ("Shutter for projection apparatus," 1942) is the on‑point reference of record for claim 8's two counter‑rotating apertured disks. Combined with any of Grounds A–C, claim 8 is a straightforward mechanical aggregation: dual‑aperture shutters and preview windows were separately known, and the claim adds no asserted cooperating function beyond simultaneous projection and preview.

4. Dependent claims 2–13

5. Counterarguments a patent owner would raise (and how they fare)

1. "Spring wire hook" is not disclosed — the case is hindsight. Strongest argument. The examiner allowed claim 1 over all ten references, which is consistent with the hook‑plus‑cassette‑cam combination being the point of novelty. Reconstructing that combination from a bayonet/loop connector plus cam surfaces requires a hindsight step — unless a wire hook is shown elsewhere in the field.
2. New function / change in principle. The specification stresses that the connecting wires must be thin and resilient because they are coiled with the strip, and that a convolution in the wire prevents hook rotation during connect/disconnect. If coiling a rigid two‑piece connector is inoperable, converting it into a resilient wire hook is arguably a change in the principle of operation, not mere substitution — a KSR/"new function" talking point worth testing.
3. Non‑analogous art. '575 and '131 are magnetic‑tape/film handling, not slide projection. Rebuttal: the field of endeavor is the transport of a flexible image/record‑bearing strip through an apparatus via a removable cassette, and the problem addressed (automatic coupling on cassette insertion) is the same. This is reasonably pertinent art under either prong of the analogous‑arts test, but it is contestable.
4. Secondary considerations. None are in the supplied record. No commercial‑success, licensing, copying, or long‑felt‑need evidence appears in the file. The specification's asserted advantages (uniform heating, no refocusing, no Newton's rings, ~1,000 slides per strip) are attorney/spec self‑serving statements, not objective evidence with a nexus. I also note, as a caution rather than proof, that the patent lapsed for fee non‑payment in 1988 — weak, non‑dispositive evidence of limited commercial uptake.

Bottom line: On this record, claim 1 is likely obvious under Ground A or B only if a wire‑hook coupling is treated as an obvious mechanical substitution for the bayonet/loop and camming couplings of '131/'575. If that substitution is rejected as hindsight‑driven, claim 1 stands — and claim 3 would almost certainly stand independently, since nothing cited shows a conductor sandwiched between offset sheet members of a strip. Claims 2, 4–6, 8 (in part), and 9–13 are individually vulnerable; claim 7 is weaker on the record as supplied.

6. Verification gaps and residual uncertainty

• I retrieved and quoted the US 3,539,131, US 3,190,575, US 2,563,893, US 3,870,412, and DE 2,549,130 disclosures directly; the mappings above are grounded in that text. Contrast: the previously generated summary's characterization of the remaining cited references (GB 419,065; US 2,269,713; GB 596,653; US 3,042,331; US 4,140,383) rests on titles/abstracts only, and I have not independently read those five specifications. My statement regarding claim 8's reliance on Erwin '713 is therefore based on its title and era, not on verified text. Treat it as a hypothesis to confirm.
• My search for US 3,591,275 (Bell & Howell) hit the tool‑call limit and returned a search‑cap message rather than results. I cannot confirm its disclosure content, so it is not relied on above.
• The best candidate for the literal "spring wire hook" limitation (a resilient hook coupling with a convolution, coilable with the strip) does not appear in the prior art of record as supplied. I searched within the record only; I have not performed a full third‑party prior‑art search for spring‑wire hook couplings in the filmstrip/slide‑strip art. Until that is done, a definitive § 103 conclusion on claim 1 cannot be stated with high confidence.
• No litigation or post‑issuance validity challenge to US 4,431,282 was located; consistent with the 1988 lapse and 2001 expiration.