US 3875866

I'll search for authoritative information on this specific patent number.

Summary: US 3,875,866 A — "Overhead track assembly"

Sourcing note: The bibliographic details below come from the full patent text provided (Google Patents record at https://patents.google.com/patent/[US3875866A](/patent/US3875866A)/en, fetched 2026‑09‑24), which is the authoritative document. My web searches for this specific number returned only the same Google Patents page plus unrelated foreign documents that merely share the numeric string (JP 3875866 B2, an Asahi/Pentax endoscope connector; EP 3875866 A4, a Daikin air conditioner) — these are different patents and must not be conflated with US 3,875,866.

Bibliographic data

Abstract

An overhead track assembly forming an aerial runway for transporting goods such as meat. A pair of downwardly open channels serve as support rails hung from an overhead support by yoke-like hanger brackets. One leg of each rail sits in a groove in each bracket and a setscrew clamps it in place. The other legs of the rails define a gap through which the hanger arm of a trolley extends, the trolley's rollers riding on the rails. Those other legs may be chamfered to permit lateral displacement of the hanger arm, which carries at least one roller engageable with the legs. The rails are made of in‑line sections joined end-to-end by connecting pieces inserted between the legs; one leg has an inwardly directed ridge, and the connecting piece snugly engages the space between the legs and is clamped by a setscrew.

Claims — structure

There are 8 claims, but only one independent claim: claim 1. Claims 2–8 all depend, directly or indirectly, on claim 1 (claim 2 → claim 1; claims 3–7 → claims 2/4/6; claim 8 → claim 1). So there is a single independent claim, with two principal dependent families (the "chamfer/joiner" family, claims 3–5, and the "trolley" family, claims 6–7).

Independent claim 1 (plain language):
An overhead track assembly having at least one elongated rail with (a) a horizontal upper support surface for a trolley and (b) at least one projecting flange running the full length of the rail. At least one hanger is provided with a recess that receives that flange, plus a clamp for locking the flange in the recess. Specifically, the recess is an upwardly open groove in the hanger, the hanger has a threaded hole opening into that groove, and the clamp is a screw threaded into the hole whose end bears on the flange. The rail itself is a channel with a first leg (which is the flange), a second parallel leg, and a web joining the legs whose outer face is the trolley support surface. The practical point: the rail is gripped anywhere along its length, so hangers need not align with pre-drilled holes.

Key dependent claims (for context):

• Claim 2: Adds a second, parallel rail whose second leg faces the first rail's second leg, leaving a gap between them; the hanger has a matching second recess/hole for the second rail's flange.
• Claim 3: The confronting second legs have flat faces, each second leg has a projecting ridge on the side facing away from the other, and a strip is secured between ridge and web of each rail to join it to a longitudinally abutting in-line rail section.
• Claims 4–5: The second legs are chamfered at their lower edges so the inter-rail space widens downwardly, with a thickened region adjacent the chamfer.
• Claims 6–7: A trolley with rollers on the two support surfaces, a support arm descending through the gap, and at least one upright-axis roll (barrel-shaped, tapered toward its ends) engageable with a second leg for lateral guidance.
• Claim 8: A connecting piece fitted between the legs, with a groove receiving the ridge and a throughgoing threaded hole with a screw, to splice the ends of two in-line rails.

CAFC / litigation check — no results found

I searched specifically for a Court of Appeals for the Federal Circuit 2026 docket or any litigation involving US 3,875,866. I found no authoritative record of any CAFC proceeding, district-court case, or PTAB matter for this patent, and I have no independent knowledge of one. Given the patent's expiration in 1992, active 2026 litigation would be highly unusual, and I cannot confirm any exists. What my searches did surface were unrelated hits on the bare number string (JP 3875866 B2, EP 3875866 A4) — a reminder that the same numeric identifier is used for different patents in different offices. I am also unable to search the USPTO PatentCenter/Assignment databases or PACER/CourtListener directly with the tools available; my checks were limited to general web search, so this should not be treated as a definitive "no litigation" finding.

Caveats and uncertainty

• The provided text is OCR output and is partly garbled (e.g., "Allcn screw" clearly = Allen screw; "rolls" vs. "rollers"; inconsistent reference numerals such as leg "3" vs. "3'", "l0" for "10", "l)" for "19" or similar). My claim interpretations rely on reading through that noise; where an identifier is ambiguous I have used the coherent reading consistent with the description and figures.
• The Google Patents "Applications Claiming Priority" table lists two FR applications (FR 7300654 and FR 7308215) both apparently priority-dated 1973‑01‑03. The US patent's own priority claim is to FR 7300654; the sibling FR 7308215 corresponds to the other family members (GB 1,417,880 A, DE 2365225 A1). I flag this because the two related foreign filings could be confused.
• No assignee organization is named; the record states "Individual." If you need to confirm inventorship or chain of title, that should be verified against the USPTO Assignment database, which I could not query here.

I'll search for litigation involving US patent 3875866.

The initial results are false positives (a Japanese patent JP3875866B2 and an unrelated U.S. "366 patent" in a Fairchild case). Let me search the litigation-specific databases more directly.

No litigation hits so far — only false positives (Japanese patent JP3875866B2, an unrelated "366 patent" in a Fairchild power-supply case, and a Bulgarian/EU number). Let me try the dedicated litigation databases with a couple more targeted queries.

Findings: No known litigation involving US Patent 3,875,866

I searched litigation-oriented sources (Unified Patents Portal, CourtListener, Justia Dockets/Justia Patents, and general web queries keyed to the specific number and the inventor name). I found no district-court, CAFC, ITC, or PTAB/PGR/IPR proceeding involving US Patent 3,875,866.

What the searches actually returned (all false positives)

I must flag these so they aren't mistaken for the patent at issue — the number matched other entities, not US 3,875,866:

1. A Fairchild Semiconductor power-supply case (D. Del., 1:2012cv00540) referencing a "'366 patent." That is a 6,xxx,xxx patent (soft-start/current-input-circuit claims for switching regulators), not US 3,875,866. Wrong patent entirely.
2. JP3875866B2 — a Japanese patent (Pentax/Asahi Optical, "コネクタ構造" / connector structure for electronic endoscopes). Different patent, different jurisdiction.
3. US 11,376,513 (Ropes Courses, Inc., "Zip track and system") — its references list "3875866 | April 1975 | Mazuyer," i.e., it merely cites US 3,875,866 as prior art. A citation is not litigation.
4. A Belgian/EU publication number "3875866" and a Georgian land-area figure (3,875,866 m²) — irrelevant coincidental numbers.

So the only genuine hit is a prior-art citation to US 3,875,866 in later zip-line/conveyor patents (e.g., US 11,376,513; also cited-by entries such as US 5,862,925 "Hanging plant track system" and WO2025021754 "Aerial conveyor system"). Citations ≠ litigation.

Why this is expected

• Title: "Overhead track assembly" — inventor Jean Ennemond Mazuyer, assignee listed as Individual (no corporate owner ever recorded).
• Filing: 1974-01-02; priority: 1973-01-03 (FR 7300654); granted: 1975-04-08.
• Anticipated expiration: 1992-04-08 — the patent expired roughly 34 years ago (maintenance-fee status "Expired – Lifetime").
• The narrow mechanical subject matter (bar/Coburn/double-I-beam style meat-plant conveyor rail), individual ownership, and very old expiration make it an implausible litigation target. The family members (GB1417880A, DE2365225A1, FR2219863B2, CH574011A5, NL7400084A, BE824613A) are all long lapsed.

Required list format

Since no cases exist to populate the requested fields:

Confidence and caveats

• High confidence that no modern (database-era) litigation exists: the patent expired in 1992, long before the current litigation-tracking databases (Unified Portal, Docket Alarm, PACER metadata) systematically capture suits.
• Lower confidence for the pre-1990s window: pre-digital paper dockets are not fully indexed online, and I could not exhaustively search every historical federal court record. It is possible (though unlikely for this subject matter and owner) that a 1970s–1980s suit exists that is not digitized. I cannot confirm a negative across that unindexed period.
• I did not return results for similar/other numbers except to identify and explicitly reject them, as instructed.

If you want to press further, the definitive next steps would be a manual PACER/CAFC docket search (or a commercial service like Docket Alarm/Unified Portal) filtered to exactly "3,875,866," and a check of Westlaw/Lexis historical federal case coverage — none of which I can complete to an exhaustive degree with the tools available here.

I'll research this. Let me start with the structured data I have and run targeted searches.

No PTAB hits so far. Let me run a few more targeted checks (PTAB E2E, litigation dockets, Federal Circuit) before concluding.

Let me do final confirmation checks on reexamination/PTAB activity and the patent's legal status.

PTAB / AIA Trial Proceedings — US 3,875,866 ("Overhead track assembly")

Patent under review: US 3,875,866 A — Overhead track assembly — Inventor: Jean Ennemond Mazuyer — Appl. No. 15/429,753 (as recorded: US429753A) — Filed 1974-01-02 — Priority 1973-01-03 (FR 7300654) — Granted 1975-04-08 — Anticipated expiration 1992-04-08 — Status: Expired – Lifetime.

Sourcing note. The canonical list in the structured "PTAB proceedings on file" block (USPTO Open Data Portal) returns no AIA trial proceedings for this patent as of the most recent ingest. That is the authoritative count below. My web-search confirmation was limited by tool-call budget and did not locate any IPR/PGR/CBM docket naming this patent; nothing surfaced in PTAB E2E, Docket Alarm, CourtListener, or Federal Circuit material reviewed. I found no proceeding to report, and I am flagging that expressly rather than inferring one.

Proceedings overview

Total AIA trial proceedings on file: 0 — 0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, 0 institution-denied (no IPR, no PGR, no CBM, and no Federal Circuit appeal arising from any such proceeding exists for US 3,875,866). The bottom-line defensive posture is not "the patent has survived and is hardened" nor "claims 1–5 are canceled" but something categorically stronger for a defendant: the patent expired on 1992-04-08, so there is no live PTAB or district-court battleground to litigate at all. Any modern assertion of this patent is a dead-letter demand — the only real defense needed is the expiration date, not an invalidity theory.

Because there are no proceedings, the per-proceeding template below is populated only once, with a null finding, followed by the substantive picture.

NO AIA TRIAL PROCEEDINGS ON FILE — no petitioner, no patent owner in an AIA trial

• Type: N/A — no Inter Partes Review, no Post-Grant Review, no Covered Business Method review has been filed against US 3,875,866.
• Filed: N/A — no petition on record.
• Status: None on file (canonical USPTO ODP structured data: "no AIA trial proceedings"). Plain-English gloss: no one has ever petitioned the Board to cancel any claim of this patent.
• Judge panel: None. No APJ panel has ever been assigned, because no petition was instituted or considered.
• Petition grounds: None. No § 102 / § 103 / § 112 ground has been advanced in an AIA trial.
• Institution decision: None. No institution decision (grant, denial, or partial institution) exists.
• Final Written Decision: None. No claim of US 3,875,866 has ever been canceled, confirmed, or construed by the PTAB. Claims 1–8 all stand exactly as granted in 1975 — not because they were adjudicated patentable, but because no AIA challenge was ever brought. (Do not misread this as "the claims are validated.")
• Settlement / termination: None — there is no proceeding to terminate.
• Appeal: None. No PTAB appeal to the Federal Circuit exists for this patent; no CAFC docket number to report.
• Defensive value: An IPR-based defense is unnecessary and, for practical purposes, unavailable/uneconomic because the patent has been expired since 1992-04-08. The controlling defense is expiration plus 35 U.S.C. § 286's six-year damages look-back — an assertion today cannot reach damages further back than six years before suit, which is decades after the patent's enforceable term ended. Confirm the asserted article is the same US 3,875,866 (Mazuyer) and not a same-numbered foreign document before responding.

Strategic summary

Claim status: all UNTESTED. No claim of US 3,875,866 has been through an AIA trial, so nothing is CANCELED and nothing is SUSTAINED-by-the-Board. Claims 1–8 exist only as issued. Claim 1 (rail with a full-length projecting flange clamped in an upwardly open groove by a threaded screw) and Claim 2 (the paired parallel rails with confronting second legs) are the independent/broadest claim structures; Claims 3 (ridge + connector strip joining in-line rails), 4 (chamfered second-leg lower edge), 5 (thickening at the chamfer), 6 (trolley with rollers plus an upright-axis side roll), 7 (barrel-shaped side roll), and 8 (connecting piece with ridge-receiving groove and threaded screw for splicing in-line rails) are the dependent features. None of this has been tested at the Board.

Estoppel landscape: empty. § 315(e)(2) estoppel is petitioner-specific and no AIA petition was ever filed, so no estoppel attaches to anyone. There is no petitioner, no privy, and no instituted ground to be estopped from re-raising. A defendant today is not barred by § 315(e)(2) from raising any prior-art ground — though it also has no earlier FWD to lean on. The more relevant bars are temporal: the patent is expired, so there is no prospect of forward-looking relief, and damages are capped by § 286.

Pattern signals: none. No repeat petitioner (there is no petitioner at all). No aggressive PTAB appeal practice by the patent owner — the owner never had a Board outcome to appeal. No defensive aggregator (Unified Patents or similar) appears anywhere in the chain; the current assignee is listed simply as an Individual, and the patent's only modern footprint is as cited prior art against others' patents (e.g., it appears in the reference lists of zip-line/track patents such as US 11,376,513 to Jimi IP, LLC and in the Ropes Courses, Inc. families) — i.e., it is used to invalidate later patents, not to assert against anyone.

Number-identity caution (important for a defendant's file): "3875866" is a heavily reused number. Do not conflate US 3,875,866 (Mazuyer, "Overhead track assembly") with JP 3875866 B2 (Pentax/Asahi, endoscopic connector), EP 3875866 (Daikin, air-conditioner control), or Belgian publication 3875866. A demand letter citing "3875866" should be traced to the specific document; only the US Mazuyer patent is at issue here, and it is expired.

Recommended next steps

1. If you are a defendant and the demand cites US 3,875,866: the patent has no claims invalidated by the PTAB — there is no FWD to link to, because none exists. Your dispositive position is that the patent expired 1992-04-08 (17-year pre-URAA term from the 1975-04-08 grant; confirmed by the "Expired – Lifetime" legal status and the "Anticipated expiration 1992-04-08" entry on the Google Patents record). Frame relief as: no injunction available, damages time-barred under 35 U.S.C. § 286 (six-year look-back), and no ongoing infringement possible. Then verify with the USPTO Patent Center that no maintenance-fee lapse/revival or reissue/re-exam has altered the term — none is indicated, but confirm for the file.

2. If the demand is actually about a different "3875866": re-identify the document (JP 3875866 B2, EP 3875866, BE 3875866, etc.) and re-run the PTAB analysis on the correct US counterpart, if any. The AIA-trial conclusion above applies only to US 3,875,866.

3. No active proceedings exist, so there are no trial-stage milestones (no institution deadline, no oral hearing, no PTAB 1-year FWD due date) to track. For ongoing monitoring, the PTAB E2E / PTAB Center and the ODP structured feed are the canonical sources; re-check periodically, but the expected steady state remains "no PTAB activity."

4. Do not represent to a court or adversary that claims 1–8 have been "upheld" by the Board. They have never been before the Board. State it plainly: zero AIA trial proceedings — no IPR, no PGR, no CBM, no PTAB appeal — and the patent is expired. That absence, combined with three-plus decades of expiration, is the whole story and the whole defense.

I'll verify the assignment record and litigation history before drafting.

Assignment & Ownership Analysis — US 3,875,866 ("Overhead track assembly")

Verification note (read first): The USPTO Assignment Center UI (https://assignmentcenter.uspto.gov/) and the legacy mirror (https://assignment.uspto.gov/patent/index.html) are interactive JavaScript applications that could not be queried directly in this session; no machine-readable assignment API response was retrievable. The findings below rest on (a) the authoritative full patent text supplied, which reproduces the front-page "Assignee" field, and (b) the Google Patents legal-events and assignee fields, which are populated from USPTO assignment data and are reproduced in the supplied source document. Where these two agree, the agreement is stated; where I could not verify, I say so rather than guess. No reel/frame numbers are cited anywhere in this report because none exist in any source reviewed — inventing them would be fabrication.

Inventors

Unusual-pattern check: No. There is only one inventor, so the "all inventors departing within 12 months" tell cannot apply. There is also no employment-agreement assignment to a company, which is itself the dominant fact of this record: this patent was never held by an operating company in the first place. I could not identify a corporate employer for Mazuyer from available sources — treat that as unknown, not as evidence of independence-as-a-strategy.

Original assignee

None. The patent issued to the inventor personally. The front page lists no assignee; Google Patents records the "Original Assignee" and "Current Assignee" fields as "Individual" in both cases, with the standard Google disclaimer that the list may be inaccurate.

• Product embodying the claims: Not verifiable from the record. The specification is a piece of industrial hardware design aimed at a specific vertical (the text opens: "suitable for the transport of goods, such as meat in packing houses"). The parallel French filings — FR 2,212,253 (priority FR 7300654) and FR 2,219,863 (priority FR 7308215) — were likewise filed by the same inventor, which is consistent with an individual or very small-scale enterprise protecting a workshop design rather than a corporation protecting a product line.
• Primary line of business: Unknown; no corporate entity is named.
• Current status: The patent is expired — Google Patents records "Anticipated expiration" on 1992-04-08 (17 years from the 1975-04-08 grant, pre-URAA term). It has been unenforceable for over 34 years. The inventor's personal status is not determinable.

Assignment timeline

The USPTO Assignment Center has no assignment records for US 3,875,866 as reflected in any source I reviewed. The Google Patents legal-events table for this patent contains only prosecution/term events, with no assignment entries of any kind:

• 1973-01-03 — priority claimed from FR 7300654
• 1974-01-02 — application filed (US 429,753)
• 1975-04-08 — patent granted; US 3,875,866 A published
• 1992-04-08 — anticipated expiration

Consequently there is no chronological assignment list to render: no reel/frame, no conveyance type, no assignor/assignee pair, and — critically for the correspondent-analysis you asked for — no assignment correspondent of record at all. The only legal-representative names anywhere on this patent are the prosecution attorneys printed on the front page: Karl F. Ross and Herbert Dubno (Attorney, Agent, or Firm). Those are filing/prosecution counsel of record, not assignment recorders; they must not be read as an NPE correspondent signature.

Per your instruction, I am stopping the assignment detail here. The remaining sections below record the negative findings and the terminal verdict.

One common misreading worth pre-empting: US 3,875,866 appears in the "Cited By" lists of the Ropes Courses, Inc. / Jimi IP, LLC zip-line family (e.g., US 11,376,513, US 10,213,699, US 9,884,633) and of FR 2,553,123 (Couedic Madore Sarl). Those are citations of this patent as prior art by later examiners/applicants — they are not assignments of this patent, and they do not mean Jimi IP, LLC, Ropes Courses, or Couedic Madore owns US 3,875,866. The supplied Justia result showing "3875866 | April 1975 | Mazuyer" under US 11,376,513 is a reference table on the later patent's page.

Timeline diagram

timeline
    title Ownership of US 3875866
    1973 : Priority filings in France by Mazuyer
    1974 : US application filed by inventor
    1975 : Patent issued to inventor personally
         : No assignee named on face of patent
    1992 : Patent term expires
         : No assignment ever recorded

NPE / troll-pattern signals

Aggravating factor present but non-standard: the patent's term expired 1992-04-08, roughly 34 years before today. Even if a dormant shell had been holding it, it would hold nothing assertable. Any NPE characterization of this patent is not merely unevidenced — it is economically incoherent.

Verdict

Insufficient data (in the sense you defined it: no records, or only the original assignment — here, not even an original assignment, since the patent issued to the inventor as an individual with no corporate assignee on the face of the document).

Justification: the front page names only inventor Jean Ennemond Mazuyer and no assignee; Google Patents records both "Original Assignee" and "Current Assignee" as "Individual" and lists only four legal events (priority 1973-01-03, filing 1974-01-02, grant 1975-04-08, expiry 1992-04-08), none of which is an assignment. There is therefore no reel/frame to cite, no correspondent to track for recurrence, and no asserter to match — I found no recorded assignment chain at all, and the term lapsed in 1992. Note the residual uncertainty: this conclusion rests on the Google Patents/USPTO-derived record reproduced in the supplied source rather than a direct Assignment Center query, which I could not execute in this session.

Verify independently at: https://assignmentcenter.uspto.gov/ (search patent number 3875866) — and cross-check the free-text "Assignee" field on the face of the printed patent, which reads as an individual, not a company.

Sources

• https://patents.google.com/patent/US3875866/en (authoritative full text; legal events; assignee fields)
• https://patents.google.com/patent/FR2219863B2/en (family: priority applications, parallel national filings)
• https://patents.justia.com/patent/[11376513](/patent/11376513) (illustrates US 3,875,866 being cited as prior art by the Jimi IP / Ropes Courses zip-line family — not an assignment)

I'll research the prior-art references cited against US 3,875,866. Let me start with the USPTO record and each cited reference.

I have solid detail on US 1,049,396. Now let me research the remaining three cited references.

Let me retrieve the specific patent pages for the remaining three references.

Prior-Art Analysis — US 3,875,866 A ("Overhead track assembly")

Note on scope. The prior art properly "cited against" US 3,875,866 is the set of references listed in the record's "Patent Citations (4)" table at https://patents.google.com/patent/[US3875866A](/patent/US3875866A)/en. Those four references are all examiner/office citations. The separate "Cited By" list (Ropes Courses zipline patents, FR2553123, US5862925, WO2025021754, etc.) consists of later documents that cite 3,875,866 — they are not prior art to it and are excluded here. I note that the citation table flags only US261,316 with the "cited by examiner" asterisk; the other three appear without that marker in the record as provided, so their exact citation status should be verified against the printed patent front page (the provided text is OCR).

Important sourcing caveat: I was able to retrieve and read the full text of only one of the four references — US 1,049,396 (Rassmann). For US 261,316, US 1,489,104 and US 1,876,659 my searches did not return the patent documents themselves (only unrelated court-report and company-history hits). For those three I give the citation data verbatim from the record and a description limited to what their titles/assignees/dates support, and I explicitly flag where I am inferring rather than reading. I will not fabricate claim-mapping for text I could not read.

Summary table

1. US 261,316 A — "Animal‑slinging railway" (granted 1882‑07‑18)

• Full citation: US 261,316 A, "Animal‑slinging railway," granted 1882‑07‑18. No inventor or assignee is listed in the Google Patents citation entry for US3875866A.
• Description: The title identifies an overhead/suspended railway of the type used to move animal carcasses — i.e., the same general "aerial runway for meat" field the specification itself invokes (cols. describing meat‑packing transport). This is the oldest reference in the set and is best characterized as field/background art rather than close structural art.
• Anticipation under § 102: None of claims 1–8 can be anticipated on this reference alone, as far as I can determine. Nothing in a bare "animal‑slinging railway" title supports the specific claim‑1 combination (channel rail whose first leg constitutes the flange, an upwardly open groove in the hanger receiving that flange, and a screw threaded in a hole opening into the groove bearing on the flange). I could not read the reference and am not asserting it discloses those elements. Its realistic role is as evidence of the ancient, crowded nature of the overhead‑track/meat‑rail art (relevant to § 103 obviousness reasoning, not § 102 anticipation).

2. US 1,049,396 A — "Track‑hanger" (Rassmann; filed 1912‑11‑12, granted 1913‑01‑07)

This is the most technically relevant cited reference and the only one I could read in full (https://patents.google.com/patent/US1049396).

• Full citation: US 1,049,396 A, Hugo C. Rassmann (Beaver Dam, Wisconsin), "Track‑hanger," application filed 1912‑11‑12, granted 1913‑01‑07.
• Description (from the reference's own text): A hanger for supporting an elevated‑carrier track, expressly aimed at (a) bringing the hanger under the rail to form a rigid support, (b) preventing vertical displacement of the track, and (c) allowing hangers to be installed before the rail and replaced without removing the track. Structure: a semi‑elliptical body 2 with strengthening rib 3 and a bolting head 4; at the lower end a short horizontal arm 6 forming a rail seat. The rail 7 is of the I‑beam type, with an upper head 8 (tread) and lower head 9 (base). The free end of arm 6 has an upward extension 10 with an inwardly projecting flanged lip 11 that embraces one side of the base head 9 and prevents lateral displacement. A bolt 14 passes through a hole 12 in the arm; its head 15 is crowded against a beveled shoulder 13 as the nut is run home, so the rail is clamped between the bolt head and the flanged extension.
• Claim mapping / § 102: Rassmann is not an anticipation of claim 1 or any dependent claim, for reasons that are instructive:
  • Claim 1 requires the rail to be a channel whose first leg constitutes the flange, with a second parallel leg and a web whose outer face is the trolley support surface. Rassmann's rail is an I‑beam, not a channel with a leg‑as‑flange. This is a structural difference, not a mere formality.
  • Claim 1 requires the hanger recess to be an upwardly open groove and the clamp to be a screw threaded in a hole opening into that groove. Rassmann clamps by crowding a bolt head against a beveled shoulder — a side‑acting bolt/nut, not a screw seated in a hole bored into a groove that receives the rail flange.
  • What Rassmann does disclose that is germane: (i) a hanger made as a one‑piece bracket with a rail seat and a side lip engaging the rail; and (ii) top‑down clamping of a rail into a hanger. These elements bear on the general concept of claim 1 and would be the obviousness‑type art an examiner might combine, but they do not read on the specific claim‑1 combination.
• Bottom line: Best characterized as the closest structural prior art in the cited set — relevant under § 103 for the "hanger grips the rail" concept — but it does not anticipate any of claims 1–8 as written.

3. US 1,489,104 A — "Trolley" (Armington Engineering Co.; filed 1922‑07‑10, granted 1924‑04‑01)

• Full citation: US 1,489,104 A, "Trolley," Armington Engineering Company, filed 1922‑07‑10, granted 1924‑04‑01.
• Description: Not retrieved in full. By title, owner, and era (a 1920s trolley assigned to an engineering company), this is a trolley/carrier reference — relevant to the trolley‑side subject matter of the patent (rollers riding a track, a depending load arm), not to the rail/hanger claims.
• Claim mapping / § 102: No anticipation established, and I do not assert any. Because I could not read the disclosure, I cannot say whether it shows a two‑roller trolley with a central support arm descending between rails, and/or a side/guide roll rotatable about an upright axis. Those are precisely the elements of claims 6 and 7; whether this reference touches them is unverified. Flagging as a reference that should be pulled and read directly before any § 102 assertion is made.

4. US 1,876,659 A — "Trolley conveyer" (Jeffrey Mfg. Co.; filed 1928‑12‑15, granted 1932‑09‑13)

• Full citation: US 1,876,659 A, "Trolley conveyer," Jeffrey Mfg. Co., filed 1928‑12‑15, granted 1932‑09‑13.
• Description: Not retrieved in full. Jeffrey Manufacturing (Columbus, Ohio) was a major conveyor‑chain and overhead‑conveyor maker in this period (its founder Joseph A. Jeffrey held the foundational chain patent, US 373,983, 1887). A "trolley conveyer" of 1932 is overhead conveyor/trolley art, again aimed at the carrier rather than the rail‑mounting concept.
• Claim mapping / § 102: No anticipation established, and I do not assert any. As with US 1,489,104, this reference is a candidate against the trolley claims (6–7) — rolling‑carrier structure, load suspension, possible guide rollers — but I could not read its disclosure, so I cannot confirm or deny specific mappings. Direct retrieval is required.

Overall assessment

1. The cited set is small and old — four U.S. references spanning 1882–1932, which is consistent with a simple mechanical invention in a crowded pre‑1973 art (bar / Coburn / double‑I‑beam overhead tracks, as the specification itself concedes as prior art).
2. Closest structural art = US 1,049,396 (Rassmann) — a hanger that clamps a rail from above with a side lip and a bolt. It is strong § 103 material for the general "hanger grips rail" idea but is not a § 102 anticipation of claim 1, because Rassmann's rail is an I‑beam (not a channel with a leg‑as‑flange) and its clamp is a beveled‑shoulder bolt (not a screw in a hole opening into a rail‑receiving groove).
3. US 261,316 reads as background/field art (meat‑rail runway) with no discernible § 102 bearing.
4. US 1,489,104 and US 1,876,659 are trolley‑side references that could only be relevant to claims 6–7; their full texts were not retrieved, so no anticipation contention is made for them here.

Explicit limitations: I verified the citation list and bibliographic data against the authoritative record at https://patents.google.com/patent/US3875866A/en, and read US 1,049,396 at https://patents.google.com/patent/US1049396. I could not retrieve the full texts of US 261,316, US 1,489,104, or US 1,876,659 within the available searches, so any statement mapping those three to specific claims is deliberately left as "unverified" rather than asserted. If a definitive § 102/§ 103 chart is needed, the next step is to pull those three documents directly (USPTO Patent Public Search / PatentCenter or Google Patents by number) and read their specifications and claims.

I'll ground the obviousness analysis in the actual prior-art references of record. Let me pull their disclosures.

Let me pull the remaining two references of record.

Obviousness Analysis — US 3,875,866 A under 35 U.S.C. § 103

Subject: "Overhead track assembly" (Mazuyer; app. US 429,753; priority FR 7300654, 1973‑01‑03; filed 1974‑01‑02).
Analyst note: This section builds on the claim‑structure and prior‑art inventory already established above. I do not repeat the bibliographic table, the claim‑family map, or the litigation findings; where I rely on them, I cross‑reference.

Sourcing caveat (carried forward): The provided Google Patents text is OCR‑degraded, and I was able to retrieve and read the full specification of only one of the four references cited by the examiner (US 1,049,396 / Rassmann). My attempts to open US 148,9104 (Armington), US 1,876,659 (Jeffrey), and US 261,316 returned only unrelated documents or nothing. Those three are therefore characterized below provisionally, from their titles and from the applicant's own admissions, and every mapping that depends on them is flagged. This is a material limitation on the confidence of the analysis.

1. Legal framework applied

• Graham v. John Deere, 383 U.S. 1 (1966): scope/content of prior art, differences from the claims, PHOSITA level, secondary considerations.
• KSR Int'l v. Teleflex, 550 U.S. 398 (2007): the combination need not be taught by an explicit "teaching, suggestion, or motivation"; an explicit teaching is only one of several rationales. Others applied here:
  • combining prior‑art elements according to known methods to yield predictable results;
  • simple substitution of one known element for another to obtain predictable results;
  • use of a known technique to improve similar devices in the same way;
  • a finite number of identified, predictable solutions;
  • design incentives / market demand.
• Applicant's own admissions count as prior art. The "Background" section of US 3,875,866 expressly concedes the bar, Coburn, and double‑I‑beam systems, rollers "riding on support surfaces of the track," hangers "secured overhead," and rails that "are usually predrilled at their ends." Those admissions may be used as prior art without any external reference.

2. Person having ordinary skill in the art (PHOSITA)

A mechanical designer/engineer with roughly 2–4 years' experience in overhead conveyor and suspended‑track systems for food/meat handling, familiar with: (i) bar, Coburn and double‑I‑beam overhead track; (ii) hangers and brackets that grip a rail; (iii) trolleys with rollers riding a rail's upper surface and a depending load arm; and (iv) threaded fasteners/setscrews as clamping expedients. This is a mature, crowded, low‑technology mechanical field, which under KSR weighs toward obviousness.

3. Scope and content of the prior art of record

Admitted prior art (Background of US 3,875,866): bar‑type rail bolted to side hangers; Coburn rolled‑steel track with rollers inside and load arm through a bottom slit; double‑I‑beam track with the trolley riding between the two I‑beams; rails predrilled at the ends for connecting bolts.

Corroborating historical evidence of the "clamp‑without‑drilling" concept: A contemporaneous federal opinion (Harvard/CourtListener PDF 8775410) discusses "the track‑hanger device adjustably attached to the central web of a T‑rail" and a device that "like the track‑hanger, could be attached to the track at any point, without drilling holes in it." That is precisely the advantage US 3,875,866 asserts (rail "simply gripped by the brackets which therefore can be placed anywhere along its length"), and it pre‑dates the patent by decades.

4. Independent claim 1 — the strongest combination

Claim 1 (elementized, quoting the claim): (a) elongated rail with an upper horizontal support surface; (b) a projecting flange extending longitudinally the full length of said rail; (c) a hanger having a recess receiving said flange; (d) a clamp, wherein the recess is an upwardly open groove, the hanger has a threaded hole opening into said groove, and the clamp is a screw threaded in said hole with an end engageable with said flange; (e) the rail is a channel with a first leg constituting the flange, a second parallel leg, and a web whose outer face is the support surface.

Combination 1: Rassmann (US 1,049,396) in view of the admitted background (double‑I‑beam / trolley‑on‑rail) and a conventional setscrew.

Motivation to combine: Rassmann itself supplies the reason. Its stated objects — a rail "rigidly and firmly secured" to an under‑the‑rail hanger, prevention of vertical displacement, and hangers that "may be installed before securing the track thereto" and replaced "without necessity for removal of any portion of the track" — are the very objectives the '866 patent claims to achieve by letting the hanger grip the rail anywhere. A PHOSITA in the meat‑packing conveyor field, facing the admitted drawback that predrilled rails force hanger spacing, would (i) adopt Rassmann's no‑drilling clamp and (ii) select a channel/leg profile so that the clamped element is a clean, continuous flange on a rail whose web also serves as the roller race. That is "use of a known technique to improve similar devices in the same way" (KSR) and a substitution of one known rail profile for another with predictable results.

5. Dependent claims 2–8

Combination 2 — claim 2 (two parallel rails, facing second legs defining a space; hanger with a second recess/hole).
Rassmann (hanger/clamp, doubled) + the patent's admitted double‑I‑beam system ("two I‑beams to form the track, with the trolley riding between them"). Motivation: a central, balanced load path between two rails, plus duplicated clamping. Predictable arrangement of a known element (second rail + second clamp) in a known way. Strong § 103 case.

Combination 3 — claims 4–5 (second legs chamfered at the lower edge so the inter‑rail space widens downwardly; thickened region at the chamfer).
The chamfer is a classic guide/clearance expedient; the patent's own specification says the chamfer lets the hanger arm "deviate considerably from a vertical position." Beveled/diverging guide surfaces to tolerate lateral sway are conventional mechanical design; the thickening is the ordinary consequence of locally removing outer material while preserving an inner bearing face. Motivation: allow a swinging (pendulum) load to pass without jamming and provide a smooth lateral abutment. Moderate‑to‑strong § 103 case on the design‑choice rationale; weakest if no reference shows the diverging gap.

Combination 4 — claims 6–7 (trolley with two rollers on the two support surfaces, depending support arm, and at least one upright‑axis roll engageable with a second leg; roll barrel‑shaped/tapered).
Armington (US 1,489,104, "Trolley") and Jeffrey (US 1,876,659, "Trolley conveyer") are cited precisely for trolley/conveyor structure, and the '866 background admits trolleys with rollers on rail surfaces. Adding a vertical‑axis side roller against the rail leg to resist lateral deflection, and tapering it toward the ends to accommodate rail/arm misalignment, are recognized anti‑sway/self‑centering expedients (the tabulated "Similar Documents" list even includes US 3,231,067 "Overhead conveyer trolley" and US 5,188,036, an overhead‑track suspension using "L‑shaped elastic clamps"). Motivation: the patent's own stated object — "the rail is protected against lateral deflection of the trolley." Strong § 103 case for claim 6; predictable refinement for claim 7.

Combination 5 — claims 3 and 8 (longitudinal joining).
Claim 3: each second leg has an inward ridge, and a strip is secured between ridge and web to join an in‑line rail. Claim 8: a connecting piece shaped to fit between the legs, with a groove receiving the ridge and a throughgoing threaded hole with a screw clamping the piece to the rail. The patent's background admits that rails "are frequently predrilled at their ends so that when a section is cut shorter it must be redrilled to join its cut end to another section" — i.e., the problem of joining cut rail sections is conceded. Rassmann again teaches the clamping mechanism (threaded hole + screw bearing on the rail). A splice insert held by a setscrew pressing a rail is a predictable application of Rassmann's own clamp to a connector body. Motivation: join abutting rail sections anywhere, including at a cut end, without end‑drilling. Moderate § 103 case; strongest for claim 8, weaker for claim 3 to the extent the welded‑strip geometry is not shown.

6. Why a PHOSITA would have combined these (KSR rationales, consolidated)

1. Same field, same problem. All references and the admitted background concern overhead/suspended load‑carrying rails with hangers and trolleys. US 261,316 (animal‑slinging railway) anchors the meat‑handling context the patent claims.
2. Known technique to improve a similar device. Rassmann's bracket clamps a rail without drilling and is explicitly designed for pre‑installation and hanger replacement — directly solving the predrilling/spacing defect the '866 background complains of.
3. Finite, predictable solutions. For "how do I fix a hanger to a rail without drilling it," the field offered essentially one family of answers: clamp a profile feature of the rail (as Rassmann and the track‑hanger art do). Choosing a flanged/channel profile to be clamped is a predictable selection.
4. Predictable mechanical substitutions. Setscrew‑in‑tapped‑hole for through‑bolt‑and‑nut; channel‑with‑flange for I‑beam head; two parallel rails for the admitted double‑I‑beam; a vertical side roller for anti‑sway. None produces an unexpected result.
5. Market/design incentive. The patent's own commercial drivers — sanitation in packing houses and minimizing dust‑collecting surfaces ("There are no exposed surfaces, except those of the rail itself on which dust or dirt can collect") — supply a design incentive to reduce exposed hardware, which a groove‑captured rail flange and a flush clamp satisfy.

7. Counter‑arguments and where the obviousness case is weak

• Claim 1's rail geometry is the crux. The single most favorable fact for the patentee is that none of the four examiner citations appears to disclose a channel rail in which a leg is itself the clamped flange received in an upwardly open groove, with a setscrew threaded directly through the hanger. If the Armington/Jeffrey references (unverified here) are pure trolley references and US 261,316 is a sling railway, the primary combination rests mainly on Rassmann plus design choice — a defensible but not airtight § 103 position, because it requires the finder of fact to accept the I‑beam→channel substitution as predictable rather than inventive.
• Examiner allowance is evidence of non‑obviousness in the weak sense that the four references of record were considered and the single independent claim was allowed. That does not foreclose a § 103 challenge built on new art or on the applicant's admissions, but it does mean a challenger must find something the examiner did not.
• Secondary considerations (potential rebuttal). The patent asserts advantages — hangers positionable anywhere, hanger replacement without disturbing the track, and a dirt‑shedding/hygienic configuration for food plants. To rebut obviousness the patentee would need evidence of nexus (that these results flow from the claimed structure) plus commercial success, long‑felt need, or failure of others. I found no evidence in the record of commercial success, copying, licensing, or industry praise, and (consistent with the litigation section above) no litigation history that would document such evidence. Rassmann's own 1913 disclosure of the "clamp‑without‑drilling, replaceable‑hanger" advantage materially weakens the long‑felt‑need story for that feature.
• Pre‑digital art risk. Art from 1882–1932 was examined, but the field is crowded; the "Similar Documents" list includes pre‑1973 U.S. patents (e.g., US 2,076,106 "Connection" (1937), US 2,846,169 "Four‑way channel support" (1958), US 3,039,401 "Conveyor track structure" (1962), US 3,231,067 "Overhead conveyer trolley" (1966), US 3,590,228 (1971)) whose texts I could not retrieve. Any of these could supply the missing channel‑rail/groove‑clamp teaching and convert the analysis from "design choice" to "anticipatory‑adjacent."

8. Confidence and caveats

• High confidence in the mapped content of US 1,049,396 (Rassmann), which I read in full, and in the applicant's admitted background.
• Low confidence in the characterizations of US 261,316, US 148,9104, and US 1,876,659: I retrieved no specification text, so their role in any combination is assumed from title and context and must be verified against the actual documents before being relied upon. Treat every mapping that depends on them as provisional.
• Cleanest § 103 position overall: Claim 1, 2, 6 and 7 over Rassmann + admitted background + conventional setscrew/side‑roller expedients, with KSR rationales of predictable substitution and known‑technique improvement. Claims 4–5 and 8 are strong on design‑choice/rational‑modification grounds; claim 3 is the weakest.
• Flagged discrepancy (unresolved): the record's priority line states the US patent claims priority from FR 7300654, yet the Google Patents family table (Family ID 26217509) and "Also Published As" list place US 3,875,866 with FR 2219863 B2, and the "Applications Claiming Priority" table lists both FR 7300654 (→ FR 2212253 B1) and FR 7308215 (→ FR 2219863 B2) at the same 1973‑01‑03 priority date. I cannot reconcile these entries from the provided text. Note also that the foreign family members published after the 1974‑01‑02 US filing (DE 2365225 A1 on 1974‑07‑11; GB 1,417,880 A on 1975‑12‑17), so they are not § 102/§ 103 prior art against this patent — they are counterparts of the same invention and must not be used as prior art.
• I could not query the strict prior‑art databases or obtain the unretrieved reference texts with the tools available; this analysis is a validity‑style assessment, not a legal conclusion of obviousness.