US 6005475

I'll verify the patent details against live sources before summarizing.

Let me run a couple of targeted checks for any litigation or CAFC activity.

US Patent 6,005,475 — Verification & Summary

Verification note on scope: I searched public web sources returning USPTO/Google Patents/Justia/uspto.report data for the exact number 6005475. I did not find any CAFC 2026 docket entry, PTAB proceeding, or district court case naming this patent. I do not have direct API access to USPTO Patent Center, PACER, or the Federal Circuit docket, so I cannot affirmatively rule out unreported activity — but no litigation hits surfaced in search. Given the patent expired in 2017 (below), litigation is unlikely.

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Bibliographic Data

Assignee discrepancy flagged: Google Patents lists "Original Assignee: Toyoda Jidoshokki Seisakusho KK" and "Current Assignee: Toyota Industries Corp." The recorded assignment (1997-09-02, REEL/FRAME 008711/0903) names KABUSHIKI KAISHA TOYODA JIDOSHOKKI SEISAKUSHO. uspto.report also lists the assignee as Kabushiki Kaisha Toyoda Jidoshokki Seisakusho. The two names are consistent with a corporate renaming rather than a transfer, but I have not verified that from a primary assignment document — treat the "current assignee" field as a database listing, not a legal conclusion.

Maintenance fees: paid at years 4 (2003), 8 (2007), and 12 (2011); no later fee data in the record provided.

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Abstract (as issued)

A communication system for a plurality of carriages that travel along a rail. A power cable extends along the rail. The cable is used to convey electric current that drives the movable bodies and is also used to carry information between the carriages. The carriages communicate with one another by superimposing communication signals on the current flowing through the cable to transmit information and by extracting communication signals from the current flowing through the cable to receive information. A control unit at a fixed station relays communication signals transmitted between different carriages. The control unit receives communication signals, which the carriages transmit, from the cable, amplifies the signals, and returns the signals to the cable. The recipient carriage receives an amplified communication signal from the cable.

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Plain-Language Overview of the Independent Claims

Claim 1 — Relay-by-fixed-station system (broadest concept).
A rail-mounted cable does double duty: it powers the carriages and carries their data. Carriages talk by injecting signals onto the cable current and by reading signals back off it. The key element is a fixed station that sits between carriages and boosts their signals — it picks signals off the cable, amplifies them, and puts them back on the cable. Structurally, the fixed station's antenna is wound around the cable and detects signals at a first predetermined frequency. Each carriage has its own antenna that is spaced from the cable by a set distance (i.e., non-contacting), used both to transmit its own signals and to receive the amplified ones.

Claim 6 — Fixed station with a directly-wound antenna coil.
Same overall architecture as claim 1, but narrowed on structure: the fixed station's antenna coil is directly wound about the cable, and the same coil both receives carriage signals and returns the amplified signals to the cable. The carriage-side antenna coil sits in the vicinity of, without contacting, the cable. This claim captures the core attenuation fix described in the spec — the fixed station couples tightly to the cable, so its retransmission is far stronger than a carriage's original transmission.

Claim 10 — Two-frequency architecture with a multi-coil carriage pickup.
The most detailed independent claim. It splits the fixed station into a transmission antenna coil (wound around the cable, injects a first predetermined frequency) and a separate reception antenna coil (wound around the cable, detects a second predetermined frequency), plus a controller that converts digital signals to AC at the first frequency and back. On the carriage side, there is a single pickup apparatus held a predetermined distance from the cable containing three coils: a feeder coil that generates induced EMF to power the carriage, a transmission coil that injects the information signal at the second frequency, and a receptor coil that detects the first frequency. A processor generates the info signal, decodes what it receives, and controls the carriage's movement based on the decoded signal.

Claim 13 — Split antennas on both ends.
Similar to claim 1, but with two separate cable-wound antennas at the fixed station (a first that detects carriage signals, a second that returns the amplified signals) and separate transmission and receptor antennas on each carriage, each spaced from the cable by its own respective predetermined distance.

Dependent claims

• 2 (on 1), 9 (on 6): two different frequencies, f1 up / f2 down, with conversion means at the fixed station.
• 3 (on 1): fixed station antenna is a coil wound directly about the cable.
• 4 (on 1), 7 (on 6): fixed station validates accuracy of received signals before relaying.
• 5 (on 4), 8 (on 7): fixed station demands re-transmission when the signal is bad.
• 11 (on 10): E-shaped pickup core with center projection carrying the feeder, transmission, and receptor coils.
• 12 (on 11): transmission coil positioned closer to the cable than the receptor coil.

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Notable Observations

1. Title says "method," but all 13 claims are apparatus/system claims. No method claim was issued. If you are assessing method coverage, this patent provides none on its face.
2. The problem being solved (from the spec): prior art (see FIG. 12) had carriages transmitting at frequency fO directly to each other. Because a carriage's antenna cannot be wound around the moving cable, signal attenuation was severe and worsened with rail length, causing erroneous reception and system shutdowns. The 6005475 fix is to route carriage-to-carriage traffic through a fixed station whose antenna is wound around the cable, so its retransmission is strong.
3. The spec's stated relay logic: f1 signals are received only by the control unit; the control unit sum-checks the data against check data D4 and, if invalid, demands re-transmission (to the identified carriage, or by polling carriages in order if the origin cannot be identified). Commands to carriages go back at f2.
4. This patent is cited in later art. Notably, JP4680924B2 (Auckland Uniservices) discusses US 6,005,475 as disclosing a system in which the HID/IPT track is "tuned to two frequencies simultaneously," and criticizes its limited bandwidth (<~50 kHz). It is also an X-category reference against JP2007511398A (Dürr track-guided transport system, WO2005037623).
5. Stated example parameters in the spec: ~200 V, 10 kHz drive current; communication signals at several hundred MHz, preferably 200–300 MHz.

Uncertainty statement: The bibliographic fields above are drawn from the Google Patents record and corroborated by Justia and uspto.report. I found no CAFC 2026 docket, PTAB filing, or litigation involving patent 6005475, and I am not asserting that none exists — only that none appeared in the searches performed.

I'll search for litigation involving US patent 6005475 across patent litigation databases.

Let me search specialized patent litigation sources.

Let me search more targeted litigation sources and the specific databases mentioned.

Search Results: Litigation Involving US Patent 6,005,475

Finding: No litigation involving US Patent 6,005,475 was identified.

Based on my searches of patent litigation resources (including Google Patents, USPTO records, and general litigation sources), I was unable to locate any district court action, Court of Appeals for the Federal Circuit (CAFC) appeal, ITC Section 337 investigation, or PTAB proceeding (IPR/PGR) in which US 6,005,475 was asserted or challenged.

Important caution on search hits: Several results referenced a "'547 patent," but these were different patents, not US 6,005,475. For example:

• The Baxter/DEKA v. Fresenius litigation (N.D. Cal., Case No. 4:07-cv-01359) involved a "'547 patent" directed to dialysis fluid membranes — an unrelated patent with a different number. I am flagging this explicitly per the strict instruction not to conflate similar patent numbers.

No source I retrieved connected US 6,005,475 to any case docket.

Patent Background (for verification of identity)

Why No Litigation Is Likely

• The patent expired on 2017-09-08 (20 years from filing), so it could not be asserted in any action filed after that date.
• It is a captive industrial/automotive-adjacent patent (conveyor carriage communication over power cables) owned by Toyota Industries — not a typical asset for NPE/patent-assertion campaigns that generate most visible litigation.
• Only two family members exist (US and JP), limiting cross-border enforcement.
• No "Litigation" or district-court docket references appeared in the Google Patents record or the "Cited By / Citing" lineages I retrieved.

Caveats

• My searches returned no docket-level confirmation either way (e.g., a Docket Alarm or Unified Patents portal record for this specific number). The absence of results here means "no litigation found," not an affirmative certification that none exists.
• To obtain a definitive negative confirmation, one would need to query a litigation-specific database (e.g., Docket Alarm, Unified Patents' litigation portal, LexMachina, or PACER) by the exact patent number 6,005,475 — I was not able to retrieve a direct responsive record from those tools.

Bottom line: No litigation involving US Patent 6,005,475 is known or was identified. If you require a certified "clear" result, a direct PACER/Docket Alarm-by-patent-number search should be run, as I could not surface a confirming docket record.

I'll verify the structured data with targeted searches before reporting.

Verification summary

I ran the structured ODP data against independent web searches (petition-number queries, petitioner-name queries on the Toyota Jidoshokki / Toyota Industries entities, and litigation-assertion queries). Every hit returned was for a different patent that happens to share the "475" shorthand — e.g., U.S. 7,766,475 (Neenah v. Schwendimann, IPR2020-00915) and U.S. 7,043,475 (the Twitter/Facebook IPR line) — none of which involve US 6,005,475. I found no petition, no institution decision, no FWD, and no CAFC appeal referencing this patent.

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Proceedings overview

Total AIA trial proceedings on US 6,005,475: zero (0). Breakdown: 0 active, 0 claims invalidated, 0 claims sustained on the merits, 0 settled, 0 institution denials. The USPTO ODP structured record reports no AIA trial proceedings for this patent as of the most recent ingest, and no web-accessible PTAB or Federal Circuit record contradicts that.

Bottom line for a defendant: There is no IPR-based shortcut and no IPR-based estoppel here. Every claim (1–13) is untested at the PTAB, so the patent stands exactly as issued on 1999-12-21, and a validity challenge would have to be built from scratch in district court — or filed as a first-instance petition. Equally, no petitioner has previously narrowed or killed any claim, so a demand letter cannot be answered by pointing to a canceled claim. The most useful facts in the record are the prior-art citations of record and the expiration date (see below), not any PTAB outcome.

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No proceedings to enumerate

There is no {PROCEEDING_NUMBER} to populate. To be explicit about what is absent rather than merely silent:

• Type: n/a — no IPR, PGR, or CBM was ever instituted or filed to the point of public docket.
• Filed: n/a
• Status: The structured block states verbatim: "The USPTO ODP API returns no AIA trial proceedings for this patent as of the most recent ingest." Plain-English gloss: no AIA trial activity on file.
• Judge panel: none assigned.
• Petition grounds: none on record.
• Institution decision: none.
• Final Written Decision: none. No claim of US 6,005,475 has ever been canceled by the Board. Claims 1–13 remain as issued.
• Settlement / termination: n/a.
• Appeal: no CAFC appeal of any PTAB decision exists, because no PTAB decision exists.
• Defensive value: n/a as a PTAB matter. For a defendant today the operative defensive assets are non-PTAB: the § 102(b)/§ 103 art already cited on the face of the patent and the patent's own expiration position.

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Strategic summary

Claim status. All thirteen claims — independent claims 1, 6, 10, and 13, plus dependents 2–5, 7–9, 11, and 12 — are UNTESTED at the PTAB. None are canceled; none are sustained in an AIA trial. The only claim-scope changes in this patent's history are prosecution-stage, not post-grant. Note that claim 10 is the apparatus claim with the most specific structure (fixed-station transmission/reception coils wound around the cable, plus a movable-body pickup with feeder/transmission/receptor coils), and claims 11–12 add the E-shaped core and the "transmission coil closer to the cable than the receptor coil" limitations — those are the narrowest, most structurally-bounded claims, and they are also the untested ones.

Estoppel landscape. There is no § 315(e)(2) estoppel attaching to this patent, because estoppel only arises from a petitioner's own instituted IPR that reaches a final written decision. No petitioner exists, so no prior-art ground is foreclosed. A defendant filing today has the full field available: the 19 references cited on the face of the patent (including US 3,714,419 to Philips; US 3,942,168, US 4,008,467, and US 4,032,911 to Westinghouse; US 5,619,078 to Boys; US 5,709,291 and JPH 05-207606 / JPH 05-344603 / JPH 06-153305 to Daifuku; US 5,531,350 to Daifuku; and US 5,562,339 / US 5,628,478 in the railway cab-signal space) plus any art the examiner never saw. Conversely, the patent owner is under no IPR-driven prosecution disclaimer, so claim-construction arguments made in any past IPR are not available to constrain it — but there is also no estoppel against the defendant.

Pattern signals. No petitioner has filed once, let alone multiple times. No patent-owner appeal aggressiveness is observable. There is no defensive aggregator (e.g., Unified Patents) anywhere in the chain. That overall absence is itself informative: this patent appears never to have been asserted in a way that drew a validity counter-punch. It was filed 1997-09-08, granted 1999-12-21, and per the structured ODP data reached anticipated expiration on 2017-09-08, with the last recorded maintenance fee payment being the 12-year payment on 2011-05-25. Its JP priority (JP 8-237732, 1996-09-09) corresponds to JP 3374668B2 and JP H10-84303A.

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Recommended next steps

• There is no FWD to link to or quote. I will not manufacture a citation to a PTAB E2E or CourtListener document for a proceeding that does not exist. The correct citation for this patent's status is the ODP record itself, surfaced via the Google Patents page: https://patents.google.com/patent/US6005475/en — and for PTAB dockets generally, https://ptacts.uspto.gov/ptabweb/ and the Board's decisions page at USPTO PTAB Decisions.
• Active proceedings: none, so there are no trial-stage milestones (no institution-deadline, no oral-hearing date, no statutory § 316(a)(11) one-year FWD due date) to track.
• If you are a defendant facing assertion: because the structured record shows an anticipated expiration of 2017-09-08, the first thing to confirm independently is whether the claim you are accused of infringing was actually live on the accused conduct dates. The '475 record lists one maintenance-fee lapse risk point: fees were paid at 4, 8, and 12 years, and the "Expired – Lifetime" status is consistent with expiration, but a lapsed-fee event mid-term would have terminated rights earlier and would be a far cheaper defense than any IPR. Verify via USPTO Patent Center rather than relying on the aggregator status string.
• If you are deciding whether to file an IPR: you are not barred by anyone's estoppel, and the Board has not construed a single term of this patent. But weigh the cost against the expiration posture — if the patent has already lapsed and you are not within the damages-recovery window, a petition is likely money better spent on a Rule 12 motion or a license-position analysis.
• Absence as signal: well-asserted, commercially meaningful patents eventually attract IPRs. This one did not. That is consistent with a narrow, era-specific monorail power-line-communication patent that was never enforced in a campaign — which reduces, but does not eliminate, the odds that a plaintiff will appear now.

Confidence statement: I have high confidence there are no AIA trial proceedings on US 6,005,475 — the canonical ODP block says so and my independent searches turned up nothing but same-number-different-patent collisions. If a recently filed petition exists and simply has not been indexed by ODP or surfaced by search, I could not see it, and I would flag that as the one residual uncertainty rather than assert it away.

Ownership Analysis — US Patent 6,005,475

Primary-source caveat up front: I was able to confirm the single original assignment record (reel/frame 008711/0903) that is surfaced in the patent's own legal-events data, but I was not able to pull a live, field-by-field response from assignmentcenter.uspto.gov during this session (the tool returned no responsive record for the exact number, and my search budget was exhausted before I could iterate). Everything below is therefore anchored to the reel/frame disclosed in the patent record itself, cross-checked against corporate-history sources. Where I could not confirm a field (notably the correspondent of record), I say so rather than guess. Treat this section as provisional pending a direct Assignment Center query.

Inventors

• Both inventors are Japanese-national employees of the assignee; the application claims priority to JP 8-237732 (filed 1996-09-09), and the US filing was executed 1997-09-02 and filed 1997-09-08 — a normal ~12-month Paris-route pipeline.
• No unusual departure pattern detected. Both inventors assigned to their employer within days of filing (execution date 1997-09-02, effective date 1997-09-02, recorded 1997-09-09). There is no evidence of a pre-issuance exodus, no separate inventor-side assignments, and no subsequent inventor-titled conveyances. Inventor behavior here is consistent with a captive corporate R&D lab, not with a portfolio being staged for sale.
• Not found: any record of either inventor appearing as an assignor on later patents sold into an NPE chain. (I could not confirm this exhaustively — flagged as unverified.)

Original assignee

• Entity named on the issued patent: Kabushiki Kaisha Toyoda Jidoshokki Seisakusho (the assignee of record in reel 008711/0903, and the assignee printed on the grant).
• Primary line of business: Industrial machinery / materials-handling — this is the Toyota group company founded in 1926 as an automatic-loom manufacturer (English trade name historically Toyoda Automatic Loom Works, Ltd.), now a major maker of forklifts, warehouse trucks, automated storage & retrieval systems, car air-conditioning compressors, and textile machinery. It is the parent-adjacent company in the Toyota group and itself the origin of Toyota Motor.
• Product embodying the claims: Yes — plausible and consistent with the record. The patent is directed to a communication protocol for the company's own monorail/ceiling-hung carriage conveyance systems (the specification's transport system 1), which is squarely within its AS/RS and material-handling product lines. This matters for the NPE analysis: the original assignee is an operating industrial manufacturer, not a holding company.
• Current status: Operating. The company changed its name in August 2001 to Kabushiki Kaisha Toyota Jidoshokki / Toyota Industries Corporation (English name; "TOYODA AUTOMATIC LOOM WORKS, LTD." → "TOYOTA INDUSTRIES CORPORATION"). This is a change of name, not a sale — the same legal entity. This is why Google Patents lists the "Current Assignee" as Toyota Industries Corp even though no transfer-of-ownership assignment for that change is surfaced. Toyota Industries remains an active, publicly listed operating company (TSE: 6201). No bankruptcy, no dissolution, no fire-sale.

Assignment timeline

Chronological list of every recorded assignment I could confirm:

• 1997-09-02 (executed) / recorded 1997-09-09 — Reel 008711/0903

  • Conveyance: Assignment (ASSIGNMENT OF ASSIGNOR'S INTEREST)
  • Assignor: Masaki Takasan; Yasuharu Odachi (joint inventors)
  • Assignee: KABUSHIKI KAISHA TOYODA JIDOSHOKKI SEISAKUSHO
  • Correspondent: Not retrieved. The reel/frame 008711/0903 record's correspondent-of-record field (attorney/firm who filed the recording) did not surface in any source I could reach. I am not going to name a firm by inference — the filing-year (1997) correspondent is most likely the prosecution firm on the application, but that is speculation and I am treating it as unknown.
  • Context: Initial employer assignment — inventors → their operating-company employer, standard captive-R&D conveyance; no consideration structure indicative of a sale.

• 2001-08 — No assignment record found. Entity renamed Toyoda Automatic Loom Works, Ltd. → Toyota Industries Corporation. Corporate-history sources confirm the August 2001 name change (toyota-industries.com Company History / Investors FAQ; Japanese securities filings state 2001年8月 社名変更). If USPTO holds a recorded Change of Name filing for this patent, I did not surface its reel/frame — flagged unclear / uncaptured. Practically, name changes are frequently not recorded against individual patents, and Google Patents simply normalizes the assignee string, which is the more likely explanation for the "Toyota Industries Corp" current-assignee label.

No post-issuance assignment (transfer, security interest, license, merger, or termination) was found for this patent. No assignment to any LLC, licensing entity, or aggregator appears anywhere in the record. The recorded chain is one link — inventors to employer — and it terminates at the original operating company.

Finding: If the Assignment Center truly has only reel 008711/0903 for this number, then the original assignee (now Toyota Industries Corporation) still owns US 6,005,475, subject only to the possible (unconfirmed) name-change recording. That is itself the answer to the ownership question.

Timeline diagram

timeline
    title Ownership of US 6005475
    1996 : JP priority application filed
    1997 : Inventors assign to Toyoda Jidoshokki
    1999 : US patent granted
    2001 : Assignee renamed Toyota Industries Corp
    2017 : Patent expired by term

NPE / troll-pattern signals

Verdict

Insufficient data — with an operating-company-ownership finding.

This is the "only the original assignment" case the rubric anticipates: the sole recorded conveyance is reel 008711/0903 (inventors Takasan and Odachi → Kabushiki Kaisha Toyoda Jidoshokki Seisakusho, executed 1997-09-02, recorded 1997-09-09). No post-issuance transfer to any LLC, NPE, or aggregator appears, so zero of the eight NPE signals is affirmatively present (one — repeat correspondent — is "unclear" only because the correspondent field could not be retrieved). The ownership reality is the inverse of an NPE chain: a single industrial manufacturer held this carriage-communication patent for its full life until anticipated expiration on 2017-09-08. If you need the name-change link and the correspondent field resolved to convert "provisional" into "certified," run a direct number search at the USPTO Assignment Center (https://assignmentcenter.uspto.gov/, search keyword "6005475") and pull reel 008711/0903's correspondent field directly.

Verification link: https://assignmentcenter.uspto.gov/ (patent no. 6005475) — and the Google Patents legal-events mirror at https://patents.google.com/patent/[US6005475A](/patent/US6005475A)/en

I'll verify the patent record and several of the cited references against live sources before building the prior-art analysis.

I have solid verification for several core references. Let me confirm details on the remaining key citations.

Prior-Art Analysis — US 6,005,475 ("Communication method and apparatus for conveyor carriages")

Note on continuity: This section builds on the previously generated summary, litigation, and PTAB sections. It does not repeat the claim-structure walkthrough; it references those claim numbers directly. One item from the earlier "Notable Observations" is developed here: the earlier summary flagged JP4680924B2 (Auckland Uniservices) as later art that criticizes the '475 disclosure — that is a citing document, not a cited reference, and is therefore out of scope for a § 102 mapping against the '475 claims. It is not listed among the 19 references of record and I have not treated it as prior art against the '475.

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0. USPTO record confirmation (patent number verified literally)

Searches for the exact string 6005475 returned the correct record and only the correct record:

• US 6,005,475 B1 / US6005475A — "Communication method and apparatus for conveyor carriages" — https://patents.google.com/patent/US6005475/en ; https://patents.justia.com/patent/6005475
• Application 08/925,346; filed 1997-09-08; granted 1999-12-21; assignee Kabushiki Kaisha Toyoda Jidoshokki Seisakusho; 13 claims.

Deliberate exclusion of similar numbers. Search hits such as US 6,008,547 (Dobler, "…" — an unrelated H04B seat-occupancy/transformer case surfaced only via a PCT search report), US 5,696,409 (Sparhawk), and US 7,766,475 / 7,043,475 (the Neenah and Twitter/Facebook lines flagged in the earlier PTAB section) are different patents. They are not prior art here and are not conflated below.

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1. Legal framework applied

The '475 application was filed 1997-09-08, before the AIA first-inventor-to-file changes (effective 2013-03-16). Pre-AIA 35 U.S.C. § 102 therefore governs. Two dates control the statutory-bar and prior-art analysis:

Reference categories used below:

• § 102(b) — patented/published before 1996-09-08 (more than one year before filing). Applies whether or not "by another."
• § 102(a) — patented/published before the applicant's invention date (≈ the 1996-09-09 priority date), by another.
• § 102(e) — U.S. patent granted on a U.S. application filed before the applicant's invention date, by another (some of these granted after the '475 priority date).

Anticipation standard applied: a single reference anticipates under § 102 only if it discloses every limitation of the claim, arranged as in the claim. Where a reference discloses only some limitations, I say so and flag it as § 103 material rather than § 102 anticipation. I do not upgrade partial disclosures into anticipations.

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2. The 19 references of record — consolidated table

Sourced from the "Patent Citations (19)" block of the Google Patents record for US6005475A. Dates shown are earliest priority/filing → publication/grant as listed in that record.

Verified against search results (spot checks): US 3,714,419 (Philips; Unified Patents lists grant 1973-01-29, Google lists 1973-01-30 — a 1-day listing discrepancy only; https://portal.unifiedpatents.com/patents/patent/US-[3714419](/patent/3714419)-A); US 4,032,911 (Westinghouse repeater confirms frequency-translation mode — https://patents.google.com/patent/US4032911); US 5,619,078 (Boys, "Primary inductive pathway" — https://patents.google.com/patent/[US5619078A](/patent/US5619078A)/en); JP H06-153305 (Daifuku "Feeder holder" — confirmed as the FIG. 9–10 background reference in the '475 spec itself).

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3. Reference-by-reference analysis

Group A — Power-line-carrier and repeater art (closest to the "relay by amplifying" and "converting means" limitations)

A1. US 4,032,911 A — Westinghouse Electric Corp. — "Signal repeater for power distribution line communication systems." Filed 1976-02-26; granted 1977-06-28. § 102(b).
Description: A repeater that detects a carrier communication signal on a power distribution line, processes it, and re-applies it to the line. Critically, the reference expressly contemplates a "frequency translation mode" in which the retransmitted carrier frequency differs from the detected frequency, and it uses signal receivers, signal generators, an amplifier, and control logic to decide which signal to couple to the line.
§ 102 mapping: This is the single most on-point reference for two specific limitations:

• Claims 1, 6, 13 — "a fixed station that relays communication signals … by amplifying communication signals received … from the cable," and (claim 13) separate first/second cable-coupled antennas returning the amplified signal.
• Claims 2 and 9 — "means for converting signals of the first signal type received from the cable to signals of the second signal type" (the repeater's frequency-translation mode).
  Honest limit: It does not disclose "a plurality of movable bodies that travel along a rail," a "cable extended along the rail" that both powers and carries data, or a movable-body antenna spaced from the cable. It is therefore not a full single-reference anticipation of claims 1/6/13, but it is the strongest § 102/§ 103 element for the relay/amplify-and-convert core, and would be the primary reference in any § 103 combination.

A2. US 3,942,168 A — Westinghouse — "Distribution network power line communication system." Filed 1975-01-31; granted 1976-03-02. § 102(b).
Description: Power-line carrier communication over a distribution network.
§ 102 mapping: Maps to the claim 1 preamble limitation of superimposed signals on power-line current. No movable body, no rail, no amplifier relay. § 103 material only.

A3. US 4,008,467 A — Westinghouse — "Power line carrier communication system having efficient carrier signal coupling of distribution secondary lines." Filed 1975-09-16; granted 1977-02-15. § 102(b).
Description: Coupling circuitry for injecting/extracting carrier signals onto power lines.
§ 102 mapping: Maps to the cable-coupled-antenna limitations of claims 1, 3, 6, 10, 13 (coupling a communication signal to the power conductor). It is a structural teaching that informs the claim-3/claim-6 "coil wound directly about the cable" limitation. § 103 material; no rail vehicle.

A4. US 4,335,381 A — Rovex Limited — "Remote control of electrical devices." Filed 1978-08-15; granted 1982-06-15. § 102(b).
Description: Remote control of electrical devices (typically via a signal path along a track/line supply).
§ 102 mapping: Maps loosely to the command-signal aspect of the '475 (controller 7a issues commands; carriage acts). No rail-carriage-to-carriage relay. § 103 background.

A5. US 3,714,419 A — Philips (US Philips Corp.) — "System for the transmission of information to a vehicle on rails." Filed 1970-06-30; granted 1973-01-29/30. § 102(b).
Description: Railway track-circuit signalling in which an unmodulated signalling signal is transmitted through the rails and additional information is superimposed as high-amplitude pulses with pulse-repetition periods coding the data; the vehicle picks up the signals from the rails and decodes/display the information.
§ 102 mapping: Maps to the "carrying information between the movable bodies / transmitting information to a vehicle on rails" concept and to the "superimposing communication signals on a current-carrying conductor" idea. However, the medium is the running rails / track circuit, not an inductive power cable, the vehicle only receives (no carriage-to-carriage transmission), and there is no fixed-station amplifier relay. It is relevant background for claim 1's rail-vehicle-information-transmission context, but it does not anticipate the relay/amplify or the power-cable-as-medium limitations. § 103 material.

Group B — Railway cab-signal pickup art (antenna/pickup adjacent to a conductor)

B1. US 5,622,339 A — Union Switch & Signal — "Plate antenna method using integral noise mitigation for railway cab signal." Filed 1994-07-15; granted 1997-04-22. § 102(e).
Description: Antenna arrangement for picking up railway cab signals, with integral noise mitigation.
§ 102 mapping: Maps to the movable-body antenna / receptor limitations (claims 1, 6, 10, 13) — an antenna on a moving rail vehicle picking up a coded signal from a wayside conductor. It does not disclose carriage transmission, power-cable medium, or the fixed-station amplifier relay. § 103 material for the pickup/antenna limitations.

B2. US 5,628,478 A — Harmon Industries — "Cab signal pickup system with motor noise reduction." Filed 1995-01-31; granted 1997-05-13. § 102(e).
Description: Cab-signal pickup with motor-noise reduction.
§ 102 mapping: Maps to the receptor coil on a self-propelled rail vehicle limitation, and is relevant to the noise/accuracy problem the '475 addresses. Same limits as B1 — no relay, no power-cable medium, no carriage-to-carriage communication. § 103 material.

Group C — Inductive power supply / pickup art (closest to the feeder coil and E-core pickup)

C1. JP H06-153305 A — Daifuku Co., Ltd. — "Feeder holder." Filed 1992-10-30; published 1994-05-31. § 102(b).
Description: The very system described in the '475's own Background (FIGS. 9–10): two cables held along a rail by a supporter; a pickup coil with an E-shaped core, a center projection, and a coil wound about the projection, opposed non-contacting to the cable, generating induced EMF to power the carriage.
§ 102 mapping: This is the closest art to the structural limitations of claims 10, 11, and 12 — specifically the "pickup apparatus … including a feeder coil" (claim 10), the "generally E-shaped cross-section having a center projection … coil wound thereabout" (claim 11), and cable-relative coil positioning (claim 12). The '475 spec admits this reference as the power-supply background. What it does not disclose is the triple-coil arrangement (feeder + transmission + receptor on one core) or any superimposed communication — so it does not anticipate claims 10–12 as a whole. It is, however, the single most likely § 103 primary reference for the pickup-core limitations.

C2. JP H05-207606 A — Daifuku — "Non-contact power supply for moving object." Filed 1992-01-24; published 1993-08-13. § 102(b).
§ 102 mapping: Maps to the claim-10 "feeder coil generates induced emf … to drive the movable body" limitation (claims 1, 10). Non-contact inductive power to a moving body. No communication overlay, no relay. § 103 material.

C3. JP H05-344603 A — Daifuku — "Non-contact feeding facilities for travelling body." Filed 1992-06-11; published 1993-12-24. § 102(b).
§ 102 mapping: Same class as C2 — inductive power to a travelling body. § 103 material for the feeder limitation of claim 10.

C4. US 5,467,718 A — Daifuku — "Magnetic levitation transport system with non-contact inductive power supply and battery charging." Filed 1992-07-20; granted 1995-11-21. § 102(b).
§ 102 mapping: Maps to the rail-traveling-body + non-contact inductive power combination (claim 10's feeder coil + rail). No communication, no relay. § 103 material.

C5. US 5,551,350 A — Daifuku — "Transporting system driven by linear motor having inductive power supply." Filed 1993-10-07; granted 1996-09-03. § 102(b) (granted 5 days before the § 102(b) bar date and 6 days before the '475 priority date — strong art on timing).
§ 102 mapping: Maps to the "movable bodies that travel along a rail" + inductive-power-supply framework (claims 1, 6, 10). No communication overlay; no fixed-station relay. § 103 material.

C6. US 5,619,078 A — Boys (Boys; assignee lineage University of Auckland) — "Primary inductive pathway." Filed 1992-05-10; granted 1997-04-08. § 102(e).
§ 102 mapping: Maps to the inductive-power pathway/pickup concept underlying claim 10's feeder coil. It is power art, not communication art; it does not disclose superimposed data or the relay. § 103 material. (As noted at the top, this is the art family that later criticized the '475 — but that criticism is not a § 102 issue against the '475.)

C7. US 5,709,291 A — Daifuku — "Device for contactless power supply to moving body." Filed 1992-05-22; granted 1998-01-20. § 102(e).
§ 102 mapping: Same class as C2/C6. § 103 material for the feeder-coil limitation of claim 10.

Group D — Peripheral / low-relevance references

D1. US 5,539,296 A — Kabushiki Kaisha Toyoda Jidoshokki Seisakusho — "Method and system of charging a propulsion battery of an electrically powered vehicle." Filed 1992-12-15; granted 1996-07-23. § 102(b). Same assignee as the '475.
§ 102 mapping: Same-assignee electric-vehicle power art. Relevant only as background for the carriage power-supply aspect; discloses no communication overlay, no relay, no carriage antennas. Not an anticipation of any claim; nominal § 103 background.

D2. JP H08-72709 A — Toyota Automatic Loom Works, Ltd. — "Travelling wheel supporting device for transportation device." Filed 1994-09-06; published 1996-03-19. § 102(b). (Toyota-group corporate family; assignee of record differs from the '475's Toyoda Jidoshokki.)
§ 102 mapping: Mechanical carriage/steering/wheel structure (see '475 FIGS. 6–7). No communication or relay limitations. Pure background; no anticipation of any claim.

D3. US 4,331,225 A — Bolger, John G. — "Power control system for electrically driven vehicle." Filed 1978-04-25; granted 1982-05-25. § 102(b).
§ 102 mapping: Electric-vehicle power control; at most background for the powered-carriage environment. § 103 background.

D4. US 4,986,187 A — Lionel Trains, Inc. — "Toy vehicle assembly with video display capability." Filed 1988-12-27; granted 1991-01-22. § 102(b).
§ 102 mapping: Hobby/model-railroad context. Only marginal relevance (signal control of a moving vehicle on a track). § 103 background at best.

D5. US 5,555,815 A — Young, Neil P. — "Model train horn control system." Filed 1994-10-13; granted 1996-09-17. § 102(e).
§ 102 mapping: Model-train control signalling. Marginal; no rail-carriage relay or power-cable communication. § 103 background at best.

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4. Ranked assessment — best potential-anticipation candidates

Ranked by how close each single reference comes to a full limitation-by-limitation disclosure of any claim:

Direct answer to "which claims does each reference potentially anticipate?"

• No cited reference, taken alone, discloses every limitation of any of independent claims 1, 6, 10, or 13. Each fails on at least one essential element: the cited art is bifurcated between (i) power-line-carrier/repeater art that has the relay/amplify-and-convert concept but no rail carriage or inductive cable (US 4,032,911, US 3,942,168, US 4,008,467), and (ii) rail-vehicle / inductive-power art that has the rail-travelling body, the power cable, and the pickup but no carriage-to-carriage superimposed communication and no amplifying relay (JP H06-153305 and the Group C references).
• § 102 anticipation is therefore weak across the board. The realistic attack is § 103: combine a power-line-carrier repeater (US 4,032,911 as primary) with a rail inductive-power/communication system (JP H06-153305; JP H05-207606) to reach claims 1/6/13; and combine JP H06-153305 (or another Group C reference) with a carriage/vehicle antenna reference (US 5,622,339 or US 5,628,478) for the claim 10-12 pickup-plus-antenna structure.
• Dependent claims 2, 4, 5, 7, 8, 9 (frequency conversion; accuracy determination; re-transmission demand) are not disclosed by any cited reference. US 4,032,911 touches conversion (claims 2/9) but says nothing about a carriage-side accuracy-check/re-request protocol (claims 4, 5, 7, 8). These limitations appear to be the '475's clearest point of novelty relative to the art of record.

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5. Caveats and residual uncertainty

1. Full-text verification of every reference was not possible. I directly verified the subject matter of US 3,714,419, US 4,032,911, US 5,619,078, and JP H06-153305 via live sources (URLs cited above). For the remaining references I relied on the title, assignee, dates, and classification supplied in the '475 record itself, which I treat as authoritative for this exercise. Characterizations of US 3,942,168, US 4,008,467, US 4,331,225, US 4,335,381, US 4,986,187, JP H05-207606, JP H05-344603, US 5,467,718, US 5,539,296, US 5,551,350, US 5,622,339, JP H08-72709, US 5,555,815, and US 5,628,478 are therefore based on their titles/assignees and should be confirmed against full text before being relied on as a § 102 position.
2. Date-listing discrepancies exist. For US 3,714,419 the Google record shows grant 1973-01-30 while Unified Patents shows 1973-01-29 (one day). Small listing differences of this kind do not change any § 102 category here.
3. I did not treat any "similar document" (e.g., US 5,938,151 A, "Communication systems employing power cables for conveyor carriages") as a cited reference. It appears in the "Similar Documents" list, not the "Patent Citations (19)." It is a same-field/same-family-context document that would warrant separate consideration as potential art (it is technically another Toyota-lineage filing), but it is not within the requested set.
4. "Potentially anticipates" is used in the conditional sense requested. I have mapped references to the claims whose limitations they most nearly meet, while stating plainly where full-limitation anticipation fails. No reference in the record supports a clean § 102 rejection of claims 1, 6, 10, or 13 standing alone.

Bottom line: Among the 19 references, US 4,032,911 (relay/amplify + frequency translation on a power line) and JP H06-153305 (E-core inductive feeder pickup — the '475's own admitted background) are the two most pertinent. Neither single-handedly anticipates the independent claims; the record supports a § 103 combination theory far better than any § 102 anticipation.

I'll ground the prior-art disclosures with targeted searches before building the § 103 combinations.

Let me gather the remaining key references.

Obviousness Analysis of U.S. Patent 6,005,475 under 35 U.S.C. § 103

Analyst's framing. This is a technical, Graham-factor analysis of the prior art of record. It assesses whether a prima facie case of obviousness could be made against each of claims 1–13; it is not a legal opinion and does not account for claim-construction positions a court might adopt or for evidence of secondary considerations that has not been produced. Per the earlier sections, no PTAB or district court has ever construed these terms or tested these claims, so no prior construction or validity ruling constrains the analysis below (see the PTAB challenges and Litigation summary sections, carried forward).

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1. Governing standard

Obviousness is measured against the four Graham v. John Deere factors: (1) scope and content of the prior art; (2) level of ordinary skill; (3) differences between the prior art and the claims; (4) secondary considerations. Under KSR Int'l v. Teleflex, a claim is obvious where it is the "predictable" use of prior-art elements according to their established functions, where a known technique is applied to improve a similar device in the same way, or where the combination was "obvious to try" with a reasonable expectation of success. Critically for this patent, the specification itself admits much of the architecture as prior art: FIGS. 10, 11(a), 11(b) and 12 and the accompanying text describe the assignee's own earlier cable-superimposition system (station-to-carriage, carriage antenna wound on a core spaced from the cable, direct station winding). That admitted art is § 102(b)-style prior art against these claims and is the natural starting point.

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2. Level of ordinary skill in the art (POSITA)

A POSITA here is an engineer (B.S.E.E. or equivalent) with 2–4 years in automated material-handling / monorail conveyor systems, familiar with (a) non-contact inductive power transfer to moving bodies from a rail-mounted power cable and the E-core pickup art (see the '475 spec's FIGS. 8–9), and (b) power-line-carrier (PLC) communication — coupling data onto a power conductor, repeaters, and frequency-translation to avoid feedback. This is a genuinely multi-disciplinary field, which matters: the examiner had to bridge the conveyor/IPT art (Daifuku, Toyota) and the PLC/repeater art (Westinghouse), and both are reasonably pertinent to the problem the '475 spec identifies (signal attenuation when a carriage injects data into a moving-cable system).

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3. Claim construction — the limitations that carry the weight

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4. Prior-art map (from the "Prior Art / Patent Citations" section of record)

I verified the disclosures of the English-language references directly; the Japanese references' content is largely characterized by the '475 specification itself (which is an admission) or by their titles/assignees as listed. I mark confidence accordingly.

Key observation for § 103: all three functional pillars of the '475 claims — (i) rail + power cable + non-contacting carriage pickup, (ii) superimposing data on the current in that cable, and (iii) a fixed amplifiying/repeating station coupled to the cable — appear separately and, in the case of (i) and (ii), together, in art of the same field that predates 1996.

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5. Obviousness of the independent claims

A. Claim 1 — the relay-by-fixed-station architecture

Pillar (i) — rail, power cable, non-contacting carriage pickup: JPH 06-153305 (and/or US 5,551,350 / US 5,467,718, US 5,619,078). Admitted prior art.

Pillar (ii) — superimposing communication signals on the current in the cable and extracting them: the '475 spec admits this as the assignee's earlier approach (FIG. 10: "Communication signals are superimposed on the alternating current flowing through the cables 53 by transmission antenna coils 64 provided on the fixed station 63"; carriage antenna 65 wound on core 66 spaced from the cables). This is also the entire subject of US 3,714,419 (information superimposed on a rail-circuit signal, picked up by on-board means) and the PLC references US 3,942,168 / US 4,032,911.

Pillar (iii) — a fixed station that receives the superimposed signal from the cable, amplifies, and returns it to the cable: US 3,942,168 discloses exactly this at the system level ("Signal amplifying repeaters are disposed in signal communication with the electrical distribution power lines, which ensure that the interrogation and response signals are at usable signal levels when they reach their intended destinations"), including repeaters that "merely amplify and retransmit the response signal back onto the primary conductor." US 4,032,911 supplies the mechanism in more detail (inductive pick-up of the line signal, amplification, re-application to the line).

Structural limitations:

• Fixed-station antenna "wound around the cable" that "detects … at a first predetermined frequency" and "returns the amplified signals to the cable." Directly read on US 4,032,911's non-metallic inductive couplers and, more plainly, on the '475 spec's own admitted FIG. 11(a) (station antenna coils "directly wound about the cables 53 at the fixed station 63"). A directly-wound, frequency-tuned coupling coil is a textbook PLC coupler — the patent's own background concedes the technique and its benefit ("decreases leakage flux and minimizes signal attenuation").
• Movable-body antenna "spaced from the cable by a predetermined distance." Admitted (FIG. 11(b)) and inherent in JPH 06-153305's non-contacting opposing pickup and US 5,551,350.

Why a POSITA would combine: the '475 spec itself states the problem — carriage-to-carriage signals suffer "flux leakage and signal attenuation" because the carriage antenna cannot be wound about the cable, and attenuation "increases … especially when using a long rail 51." Inserting an amplifying repeater into an attenuated power-line channel is the single most established remedy in the PLC art (US 3,942,168; US 4,032,911). The motivation is not merely "design choice" — it is the recognition of a known deficiency in a known system, remedied by a known technique. That is KSR Rationales C and D ("known technique to improve a similar device in the same way" / "applying a known technique to a known device ready for improvement to yield predictable results").

Claim 1 is, in my assessment, the most vulnerable claim on the face of this record. Its only non-trivial element relative to the admitted art is relocating the "key station" relay function so that it bridges two mobile units rather than a central terminal and a remote terminal — a difference of network topology that does not change the relay's function and is, at most, an obvious design variant (KSR: "predictable variations").

B. Claim 6 — same architecture, fixed antenna "directly wound"

Claim 6 is narrower than claim 1 in that it requires the fixed-station coil to be directly wound about the cable and to serve as both receive and transmit coil. Both features are in the admitted prior art (FIG. 11(a): coils 64 "directly wound about the cables 53"; and the spec's own description of the dual-purpose transmit/receive coupling). US 4,032,911 independently teaches non-metallic inductive coupling coupled to a repeater, and the optional single antenna coil transmitting and receiving is expressly noted as an alternative in the '475 spec's own "modifications" section. Claim 6 adds little nonobvious weight over claim 1; if anything it concedes the directly-wound coupling as the mechanism and therefore narrows toward the admitted art.

C. Claim 10 — two-frequency architecture with a three-coil E-core carriage pickup

This is the most structurally specific independent claim, and it is a combination of four separately known elements:

1. Fixed station with a transmission antenna coil and a separate reception antenna coil, both wound around the cable, at different frequencies, with a controller converting digital↔AC: the frequency-translation repeater of US 4,032,911 (receiver/generator pair, "the frequency of the signal generator would be different from the frequency detected by the associated signal receiver"; "modems and demodulators may be associated with the receivers and generators to apply the intelligence … to the retransmitted signals") and US 3,942,168 (addressable terminals, interrogation at one band, response at another).
2. High-frequency drive current through the cable (e.g., 10 kHz): US 5,619,078 (10–50 kHz primary, conveyer-rail geometry) and US 5,551,350 (induction wire lines).
3. A single pickup held a predetermined distance from the cable containing a feeder coil (EMF for drive) plus separate transmit and receptor coils: the admitted E-core pickup of FIGS. 8–9 gives the feeder coil and the E-core/projection; the additional antenna coil(s) wound on the same core are exactly the admitted FIG. 11(b) carriage antenna plus the admitted station-side antenna function relocated onto the carriage core. Combining power and data windings on one E-core is a simple substitution of known elements (KSR Rationale B) with a predictable result.
4. Processor that decodes received data and controls carriage movement: conventional; the '475 spec treats the CPU 22/motor 16 control loop as routine, and automated-warehouse cars (US 5,551,350) are command-controlled.

Motivation: running a repeater at a different frequency than the incoming signal is a classic anti-feedback/anti-oscillation measure — the very reason given in US 4,032,911 ("the repeater changes the frequency band … enabling the amplifier gain … to be selected without limitation due to undesirable feedback and oscillation") and US 3,942,168/3,942,170 ("the repeaters change the frequency band … so that the gain … may be selected without limitation due to feedback"). A POSITA building the FIG. 10/11 admitted system with a relay would adopt frequency translation for exactly that reason and with a reasonable expectation of success.

Claim 10 is more defensible than claims 1/6 because it requires the specific three-coil, one-core carriage pickup and the split station coils and the two-frequency conversion in one claim. But each sub-element is known and their aggregation produces only the expected aggregation of benefits.

D. Claim 13 — split antennas on both ends

Claim 13 = claim 1 with two cable-wound fixed-station antennas (one to receive, one to return amplified signals) and separate carriage transmission and receptor antennas each spaced from the cable. US 4,032,911 discloses distinct receiver and generator sections coupled to the line; the '475 spec itself states the alternative of "a single antenna coil that transmits and receives signals." Splitting one antenna into two is the kind of predictable structural variation (KSR) — done to separate f1 and f2 channels — that does not rise to patentable weight absent evidence of an unexpected result. Two collocated coils at the same station performing the two functions is essentially a design choice over one coil.

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6. Obviousness of the dependent claims

On claim 12 specifically: this is the one limitation with a plausible nonobviousness story — one could argue it reflects a recognition that only the uplink is attenuating, and that a POSITA would not have known which coil to move without that insight. But the spec supplies no data showing the placement produces an unexpected result beyond improved coupling, and "position the winding that needs better coupling nearer the coupling source" reads on KSR's "predictable variation of a known element." I would rate this the second-most defensible claim after claim 10, but not clearly nonobvious.

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7. Motivation-to-combine summary (KSR rationales)

• Rationale A — known elements combined for their established functions: rail + power cable + inductive pickup (Daifuku/Toyota art) + PLC repeater (Westinghouse art) → claimed system, yielding the predictable aggregate of propulsive power and reliable data.
• Rationale C/D — known technique to improve a similar device / apply to a known device ready for improvement: the '475 background frames attenuation as the problem; amplification/repeating and frequency translation are the settled remedies in the analogous PLC field.
• Rationale B — simple substitution: E-core pickup with data windings substituted for a data-free power pickup; single fixed antenna substituted for two (or vice versa).
• Rationale F — design incentives/market forces: longer rails and more carriages create a known incentive to extend communication range — precisely the spec's stated objective. Competitive pressure in automated warehousing (Daifuku, Toyota Jidoshokki) supplies the "market force" motive.
• Reasonably pertinent art: the conveyor/IPT art and the PLC/repeater art both address "communicating over a conductor that also carries power," and the cab-signal art (US 3,714,419, US 5,622,339, US 5,628,478) addresses "reading data from a rail conductor onto a moving vehicle with a non-contacting antenna."

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8. Secondary considerations (Graham factor 4)

No evidence of the classic objective indicia appears in the record: no litigation and no IPR, so there is no defendant-side evidence of copying, licensing demands, or industry praise; no long-felt-but-unsolved-need evidence is of record; the "problem" (attenuation over long rails) was identified by the applicant, and solving it with a repeater is not an unexpected result. A patent owner would need a nexus between any commercial success of Toyota's conveyor systems and the specific claimed relay architecture — a hard showing where the claimed advantage (stronger fixed-station retransmission because the coil is wound on the cable) is the expected consequence of the admitted directly-wound coupling. Absent such evidence, the secondary factors do little to rebut a prima facie case on claims 1–11.

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9. Counterarguments — why the examiner allowed, and what survives

1. The references were of record and the claims still issued (1999-12-21). The examiner had US 3,942,168, US 4,032,911, US 3,714,419, JPH 06-153305 and the Daifuku family before him. That is meaningful evidence that the specific combination — a relay between two mobile carriages using a directly cable-wound fixed-station coil with two-frequency conversion — was not viewed as squarely disclosed. A defendant's § 103 case must therefore supply the missing motivation and reasonable expectation of success, and here that is doable but not trivial.
2. The "between movables" topology is the genuine nub. US 3,942,168's repeaters primarily bridge a central terminal and remote terminals, or bypass a transformer; the '475 insight is that carriage-to-carriage traffic should be routed through the fixed station because the fixed station couples tightly to the cable. That is a real, if modest, insight — and it is the difference that could tip claims 10 and 12 (and possibly claim 1) toward nonobviousness in a litigated fight with a well-briefed POSITA and objective evidence.
3. Claim 10's aggregation is the strongest nonobviousness position on this record.
4. The title says "method" but all 13 claims are apparatus claims (carried forward from the patent summary). § 103 analysis therefore attaches to apparatus structures only; there is no method claim to attack or defend under § 103, and no method claim to invalidate on the alternative § 101/112 grounds the title might have invited.

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10. Conclusion

Would support a prima facie § 103 rejection: claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 11 — each is the predictable combination of (i) admitted/prior-art rail + power-cable + non-contacting pickup systems (JPH 06-153305; US 5,551,350; US 5,467,718; US 5,619,078), (ii) admitted/prior-art data superposition on that cable (US 3,714,419; the '475 spec's own FIG. 10), and (iii) the power-line-carrier amplifying/frequency-translating repeater (US 3,942,168; US 4,032,911), with ARQ (claims 5, 8) and E-core data-winding integration (claim 11) as known techniques applied to known structures.

Contestable but likely obvious: claims 12 (transmission coil nearer the cable — result-effective placement) and, less strongly, 13 (split fixed-station and carriage antennas — predictable partitioning).

Weakest obviousness case / most defensible: claim 10, which requires the complete two-frequency, split-station-coil, three-coil-E-core-pickup, processor-controlled aggregation. It is still an aggregation of known elements, but it is the claim on which a patent owner would most plausibly survive a § 103 challenge on this record.

Confidence statement. I have high confidence in the disclosures of US 3,942,168, US 4,032,911, US 3,714,419, US 5,619,078, US 5,551,350 and US 5,551,350's family, which I verified from primary text. I have moderate confidence in the content of US 4,008,467, US 4,331,225, US 4,335,381, US 4,988,187, US 5,622,339 and US 5,628,478, which I relied on by title/assignee from the face of the '475 patent rather than verified primary text. The Japanese references JPH 06-153305, JPH 05-207606 and JPH 05-344603 are characterized here primarily through the '475 specification's own admissions and FIG. 9, which is the appropriate and reliable source for an obviousness analysis (applicant admissions), but I did not retrieve the Japanese originals and do not overstate their contents. Where I have asserted a specific disclosure that I could not verify, I have flagged it. This analysis is a technical assessment, not a legal conclusion of invalidity.