US 4464997

I'll search for authoritative information on this patent number, including any litigation or docket activity.

Let me check for any litigation, PTAB, or CAFC activity involving this patent.

US 4,464,997 — Verification Summary

Important caveat on search results first: No authoritative USPTO PatentCenter or CAFC source surfaced in my searches. The pages returned were Google Patents, Justia, and the aggregator uspto.report, plus a cached Webb company credit report. I also found no CAFC docket activity in 2026 for this patent, and I flag below two identifiers that are frequently confused with it.

Bibliographic data (from the patent text you supplied + Google Patents record)

Abstract (verbatim)

"A conveyor comprising a track formed by a pair of longitudinally extending track members providing a pair of transversely spaced supporting surfaces and a pair of transversely spaced guide surfaces; and a trolley having a body on which supporting wheels and guide rollers are rotatably mounted. The trolley body includes a shield member that is disposed adjacent to the guide rollers, extends radially outwardly of the periphery thereof, and overlaps the guide track surfaces engaged thereby. A socket, formed in the trolley body and having one end closed by the shield member, movably supports a driving dog which has a stem portion projecting into the socket and engaged therein by rollers and wear plates carried by the trolley body. The shield member is located above the trolley and forms a cover that protects the moving parts of the trolley from contamination and decreases the possibility of a foreign object becoming wedged between the guide rollers and guide track surfaces."

Plain-language overview of the two independent claims

Claim 1 — the improved trolley (driving‑dog socket). This is a "Jepson‑style" improvement claim. The assumed prior art base is a conveyor trolley having (a) a body, (b) longitudinally separated pairs of transversely spaced supporting wheels, (c) a pair of longitudinally spaced guide rollers, and (d) a shield member on the body sitting outboard of the guide rollers, extending perpendicular to the rollers' axes, with portions projecting longitudinally and transversely beyond the rollers' peripheries. The improvement is three things: the trolley body is formed with a socket positioned longitudinally between the wheel pairs, centered transversely, running parallel to the guide‑roller axes, with an open end and an opposite end closed by the shield member; a driving dog whose stem portion extends into the socket from the open end; and means inside the socket supporting the stem so the dog can move between extended and retracted positions. In short: bury the driving dog's sliding stem in a body socket that the shield member caps off.

Claim 10 — the improvement in a conveyor combination (track + trolley), with a specific stem support. Framed "In a conveyor comprising a track formed by a pair of longitudinally extending track members having a pair of transversely spaced supporting surfaces; and a trolley having a body, longitudinally spaced pairs of wheels on the body engaging the supporting track surfaces, and a driving dog movable between extended and retracted positions." The improvement: the trolley body has an integrally formed socket located longitudinally between the wheel‑pair axes and centered transversely, extending parallel to the guide‑roller axes, with an open end and an opposite closed end; the driving dog's stem portion enters through the open end; and the supporting means is specifically recited as (i) wear plates spaced apart transversely of the socket and slidably engaged by the stem, and (ii) a plurality of rollers engaged by the stem, mounted between the wear plates on axle members extending transversely of the socket and spaced apart lengthwise. Claim 10 is the narrower, structurally-committed version — it ties the claim to the roller/wear-plate/axle subassembly rather than the generic "means" of claim 1.

Dependent claims (for context): 2, 3, 7, 8 depend on 1; 4 depends on 1/2/3; 5 on 3; 6 on 5; 9 on 8; 11 on 10; 12 on 10 or 11; 13 on 12. Notable limitations: roller(s) on a transverse axle with slot means on the stem (claim 3); wear plates attached to the axle member (claims 6, 11); open end of socket directed toward the supporting track surfaces with the dog biased to extended position by its own mass (claims 7, 12); and slot‑means/roller interaction defining the extended position (claim 13).

Foreign family (11 jurisdictions, same priority)

AU 556921B2, DE 3300991A1, GB 2113166B, FR 2519923B1, KR 890000417B1, CA 1200222A, ES 519042A0 / ES 8401407A1, BR 8300207A, MX 156028A, AR 231627A1. Notably, the CIP's parent Ser. No. 06/340,112 (1982‑01‑18) is listed as a related parent application.

Two identifier traps I want to flag explicitly (per your instruction to read IDs literally)

1. "US 4464997 P" appears in the priority data of EP 0872218 (a dental‑prosthesis patent). That is a US provisional application serial number, an entirely different identifier type from granted patent 4,464,997. It is not the same invention and should not be conflated.
2. Jervis B. Webb Co. v. Southern Systems, Inc., 742 F.2d 1388, 222 USPQ 943 (Fed. Cir. Aug. 16, 1984) is a real Webb CAFC case, but the asserted patent there was the '352 patent (U.S. 4,274,352), not 4,464,997. That litigation also predates the '997's issuance (Aug. 14, 1984), so it cannot involve this patent.

Uncertainty statement

• I did not obtain a live USPTO PatentCenter or CAFC docket record. The status "Expired – Lifetime" (anticipated expiration 2002‑01‑18) comes from the Google Patents record, which the USPTO's own data feeds; treat it as reliable but not independently re‑verified here.
• Because this patent expired in 2002, a 2026 CAFC docket entry asserting it is essentially impossible; the most plausible 2026 appearance would be as prior art cited in an IPR or district‑court proceeding involving a later patent. I found no such citation in my searches, and I cannot confirm one exists.
• The Google Patents "Prior art keywords" list (socket, trolley, stem portion, supporting, conveyor) and the prior‑art references (e.g., US 1,920,774 Webb; US 3,229,645 Webb; US 3,375,790; US 2,043,357; GB 987097; GB 1,263,299; US 3,412,129 is not listed — the listed ones are US 3,418,948, US 3,869,989, US 3,882,793, FR 1,516,520, CA 516,865, CA 756,365) are as your document shows; I did not independently re‑pull the examiner's citation record.
• One drafting quirk worth noting for any validity analysis: claim 10's recited socket "extend[s] substantially parallel to the axes of the guide rollers," yet the preamble of claim 10 does not positively recite guide rollers (only supporting wheels). That antecedent‑basis gap is a potential §112(b) attack vector, but I state it as an observation, not a legal conclusion.

Grounding sources: Google Patents record for US4464997A (https://patents.google.com/patent/US4464997A/en), Justia (https://patents.justia.com/patent/4464997), uspto.report (https://uspto.report/patent/grant/4,464,997), and the Webb/Southern Systems decision (https://law.justia.com/cases/federal/appellate-courts/F2/742/1388/[212979](/patent/212979)/).

I'll search litigation sources for US patent 4464997.

Let me check dedicated litigation databases directly.

Let me do a couple of final targeted checks on litigation databases and PTAB.

Summary: No litigation found for US Patent 4,464,997

I searched the sources you specified (Unified Patents litigation portal, PACER/CourtListener-style case records, and general litigation-indexed web sources) for the specific patent number 4,464,997. I found no litigation — no district court complaints, no declaratory judgment actions, no ITC investigations, and no PTAB proceedings (IPR/PGR/CBM) involving US 4,464,997.

This is therefore a "no known litigation" answer, not a case list. I cannot provide plaintiff, defendant, jurisdiction, case number, or outcome for a case that does not appear in the searched records.

What the searches did return (and why it isn't a hit)

Per your strict rule, I have not merged these into the patent; they are distinct identifiers that merely share digits.

Contextual notes (not litigation)

• Patent: US 4,464,997, "Conveyor trolley and track," inventor Clarence A. Dehne, assignee Jervis B. Webb Company. Filed 1982‑07‑26 as a continuation‑in‑part of Ser. No. 06/340,112 (filed 1982‑01‑18); granted 1984‑08‑14. Source: https://patents.google.com/patent/US4464997/en
• Status: Expired – Lifetime. The record shows fee payments at the 4‑, 8‑, and 12‑year intervals, with an anticipated expiration of 2002‑01‑18. The patent is therefore long expired, which is consistent with never having generated litigated assertions.
• Foreign counterparts (AU 556921B2, GB 2113166B, CA 1200222A, DE 3300991A1, FR 2519923B1, KR 890000417B1, ES 519042A0, BR 8300207A, MX 156028A, AR 231627A1) likewise show only prosecution/grant data, not litigation.

Confidence and limitations

• High confidence that the patent was never the subject of a publicly reported US patent infringement suit: it is a specialized mechanical "power and free" conveyor trolley patent from a single company (Jervis B. Webb, later part of Daifuku), expired since 2002, with no appearance in the litigation-tracked sources searched.
• Caveat: I could not access paywalled comprehensive dockets (e.g., Docket Navigator, Lex Machina, full PACER). My searches covered the Unified Patents portal, publicly indexed court documents, PTAB records, and Google/Justia/uspto.report patent pages. A docket-level negative can never be stated with absolute certainty, so I would characterize this as "no known or reported litigation" rather than a certified affirmative finding of none.
• If you need a belt-and-suspenders verification, the definitive checks would be an RPX/Docket Navigator patent-owner query by patent number and a PACER "Nature of Suit 830" party search filtered on "Jervis B. Webb" for the 1984–2002 enforcement window.

Bottom line: No litigation is known for US 4,464,997. I did not return results for similar numbers (e.g., the 60/044,997 provisional or the '499 patent from the naltrexone cases), per your instruction.

I'll verify the structured "no proceedings" default against public sources before finalizing.

Proceedings overview

Total AIA trial proceedings on US Patent 4,464,997: 0. The structured "PTAB proceedings on file" block supplied for this patent shows zero IPR, zero PGR, and zero CBM proceedings — no institution decisions, no Final Written Decisions, no settlements, no PTAB-to-CAFC appeals. Breakdown by status is therefore trivially: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0. My independent web search returned nothing to disturb that default; no PTAB decision, dispatch, or docket entry naming U.S. Patent No. 4,464,997 surfaced. Bottom line for a defendant: the absence of PTAB activity here is not exoneration — it is the fingerprint of a dead patent. The '997 patent's own legal events record shows "Anticipated expiration" on 2002-01-18 and current status "Expired - Lifetime" (Google Patents US4464997A). It expired roughly a decade before the AIA trial regime opened on 2012-09-16. Nobody IPRs a patent that has been free for the public to practice for nearly a quarter-century.

Proceedings

None. There are no proceedings to summarize. Per the operating constraint against fabrication, I am not supplying a proceeding number, panel, or disposition for a proceeding that does not exist. Anything that purports to be "IPR2014-XXXXX, Somebody v. Jervis B. Webb, on US 4,464,997" should be treated as fabricated unless the requester can produce the PTAB document from E2E.

Two structural points explain the empty set:

1. The AIA trial clock started after the patent died. IPR/PGR/CBM petitions first became available 2012-09-16. The '997 patent's 20-year term from its earliest U.S. filing date (1982-01-18, the Ser. No. 06/340,112 CIP parent) ran out on 2002-01-18. It was already expired by more than ten years when the first IPR was ever filed.

2. This patent is categorically ineligible for two of the three AIA trial types. PGR reaches only patents whose claims have an effective filing date on or after 2013-03-16 — impossible for a 1984 grant with a 1982 priority date. CBM reaches only "covered business method" patents in the financial-services field (the transitional program also sunset on 2020-09-16) — a power-and-free conveyor trolley with a driving-dog socket is not a CBM. Only IPR was theoretically available, and against an expired patent it offers a defendant essentially nothing that a motion to dismiss doesn't already provide.

One confusable item, flagged so you don't mis-cite it. A 1984 case, Jervis B. Webb Co. v. Southern Systems, Inc., 742 F.2d 1388 (Fed. Cir. 1984), Appeal No. 84-568, is widely retrievable and looks on point (CourtListener PDF; full text). It is not a PTAB proceeding, and it is not about the '997 patent. It is an Article III appeal from the W.D. Tenn. (Civil Action No. 80-2465-M) on U.S. Patent No. 3,451,352, a different Webb patent. The court affirmed invalidity for obviousness as to claims 1, 3, 4, 8, 9 and 11 and vacated as to claims 2, 5-7, 10 and 12 for lack of a declaratory-judgment case or controversy. It has zero estoppel or preclusive effect on the '997 patent.

Strategic summary

Claim status: 100% untested, 0% canceled, 100% expired. No claim of US 4,464,997 — independent claims 1 and 10, or dependents 2-9 and 11-13 — has ever been canceled or upheld in an AIA trial, because no AIA trial was ever filed. The claims have not been narrowed through post-grant proceedings. But for a defendant this is a distinction without a difference: every one of claims 1-13 was forfeited to the public on 2002-01-18 when the term ran from the 1982-01-18 priority date (Google Patents legal events). A claim that has expired is not "hardened" and not "vulnerable" — it is simply unenforceable going forward.

Estoppel landscape: no IPR estoppel exists, and none is needed. 35 U.S.C. § 315(e)(2) estops a petitioner and its privies from raising in litigation any ground they raised or reasonably could have raised in an IPR. Because no IPR was ever instituted against the '997 patent, no § 315(e)(2) estoppel attaches to any party — every prior-art ground is nominally "available." That is a trap for the unwary: there is no need to invest in an invalidity case at all. The prior-art universe the defendant would legitimately want (the twelve references cited on the face of the patent, including US 1,920,774 Webb, US 2,043,357 Strauss, US 3,229,645 Webb, US 3,375,790, US 3,418,948 Fromme, US 3,869,989 Redman Fisher, US 3,882,793 Nakanishi, GB 987,097, GB 1,263,299, FR 1,516,520, CA 516,865 and CA 756,365) is still fully usable — but the operative defense is expiration, not anticipation. The old district-court/CAFC precedent on Webb's sister patent (the '352) confirms that this family's broad "driving dog" claims historically fared badly against combination prior art, which is worth knowing if someone ever resurrects a related, unexpired Webb-family patent.

Pattern signals: none. No petitioner has filed on this patent, repeatedly or otherwise. No defensive aggregator (Unified Patents or similar) appears anywhere in the chain — the '997 patent's only online footprint in a defensive context is a citation in the prior-art listing of an unrelated later patent (US 11,376,513, Ropes Courses/Jimi IP). The patent owner, Jervis B. Webb Company (Farmington Hills, MI; now part of Daifuku North America), has not pursued PTAB appeals on this patent — there was nothing to appeal. Note the asymmetry with Webb's actual litigation posture: Webb did appeal PTAB-free in the 1980s and lost the '352 patent's claims on obviousness. That litigiousness is 40 years stale.

Recommended next steps

• If you are a defendant and someone is asserting US 4,464,997 against you today, lead with expiration, not with PTAB. The patent is expired — status "Expired - Lifetime," anticipated expiration 2002-01-18 (Google Patents). Under 35 U.S.C. § 286 the damages lookback is six years, i.e. 2020-09-30 forward on today's date; every day of that window postdates the expiry. There is no recoverable infringement period. Demand a written explanation of what damages theory survives that arithmetic, and treat an assertion letter citing claims 1-13 as sanction-relevant under Rule 11 if filed in suit.
• There is nothing to petition. Filing an IPR on an expired patent would be a fee-burning exercise: the patent owner cannot amend, and cancellation of expired claims buys a defendant nothing it doesn't already have. Do not search for a nonexistent prior IPR to piggyback on.
• Verify the record yourself before relying on this memo in a filing. The authoritative sources are the USPTO PTAB E2E system and the USPTO PTAB Decisions database; the ODP structured block used here reported no proceedings as of the most recent ingest. If you turn up any AIA trial naming "4,464,997" that the ODP has not indexed, send it to me — I could not find one, and per the ODP default I am treating the absence as accurate.
• Beware of AI-generated docket entries. Given this patent's clean online profile, it is exactly the kind of record a hallucination-prone research tool will "fill in" with a plausible IPR number and an invented panel. Everything in this memo above the line marked "0 proceedings" is what the record actually supports; the Webb/Southern Systems '352 case is real but is a different patent and a different tribunal.

Confidence note: I have high confidence in the zero-proceeding finding as reported by the ODP-derived structured block and corroborated by web search, and high confidence in the 2002-01-18 expiry (I am relying on the Google Patents legal-events entry rather than recomputing the URAA transitional term myself, though that entry is consistent with a 20-year term from the 1982-01-18 priority date). I have not personally inspected the PTAB E2E docket for this patent number; if the stakes warrant it, pull the E2E record directly.

I'll research the assignment record and ownership chain for US 4,464,997.

Let me verify the assignment records directly and check for post-issuance transfers.

Inventors

Clarence A. Dehne — sole named inventor. Residence on the face of related Webb filings is Orchard Lake / Farmington Hills, Michigan (see, e.g., US 3,377,962: "Clarence A. Dehne, Orchard Lake, Mich., assignor to Jervis B. Webb Company, a corporation of Michigan"; US D277,040 lists "Clarence A. Dehne (Farmington Hills, MI)").

Employer at time of filing: Jervis B. Webb Company, Farmington Hills, Michigan. This is determinable with high confidence, not inferred from the assignee name alone: (a) the application was filed with a contemporaneous "ASSIGNMENT OF ASSIGNORS INTEREST" from Dehne to Webb (Reel 004025/0272), and (b) Dehne is a career Webb engineer, naming Webb as assignee across a decades-long string of conveyor patents — US 3,229,645 (1966), US 3,377,962 (1968), US 3,543,689, US 4,222,481 (1980, with Martin Pachuta), US D277,040 (filed 1981), US 4,464,997 (1982), and US 4,616,570 (filed 1983‑10‑14 as the same subject-matter family).

Unusual-pattern check: Not present. There is no signal of inventor flight. Dehne kept assigning to Webb before and after this filing, spanning roughly 1965–1986. The "all inventors departed within 12 months of filing" precursor to a portfolio fire-sale is affirmatively contradicted here.

Additional note on the application itself: US 4,464,997 is a continuation-in-part of Ser. No. 06/340,112, filed 1982‑01‑18 (now abandoned), same inventor, same assignee. The CIP parent is a procedural event, not an assignment, but it is why the patent's "priority date" is listed as 1982‑01‑18 while the filing date is 1982‑07‑26.

Original assignee

Jervis B. Webb Company, a corporation of Michigan, Farmington Hills, MI (original assignee; confirmed in the assignment record and in the patent's front-page data at https://patents.google.com/patent/US4464997/en).

• Primary line of business: material handling systems — overhead and power-and-free chain conveyors, automated guided vehicles, automated storage and retrieval systems, and airport baggage handling systems. Founded 1919; credited with early rivetless chain conveyor work for Ford. Headquartered Farmington Hills, MI with plants in Harbor Springs and Boyne City, MI; Carlisle, SC; plus Canada, India and China.
• Did they ship a product embodying the claims? Yes, with high confidence. The specification itself frames the invention as an improvement to the trolleys Webb was already building and selling into "power and free conveyor" systems, and identifies the commercial context (power track mounted below the carrier track, load carriers of the type shown in Webb's own US 3,229,645 and US 3,375,790). Webb was a ~1,800-employee, ~US$301.5M-revenue operating manufacturer in the 2019 period. This is an operating-company patent, not a licensing asset.
• Current status: Operating, as a wholly-owned subsidiary of a public company. Jervis B. Webb Company's shares were purchased 100% by Daifuku Co., Ltd. (Osaka; Tokyo Stock Exchange code 6383) under a share purchase agreement dated 2007‑11‑15, closing December 2007 (https://www.daifuku.com/cn/local_news/2021/0616_01/; http://www.daifuku.com/dbps_data/_material_/DFK_Global/ir/library/_res/pdf/20071115e.pdf). Effective 2024‑01‑01, the entity was renamed Jervis B. Webb Company → Daifuku Airport America Corporation (https://www.daifuku.com/vn/company/news/2023/1229_01/). Rhode Island corporate records show the RI qualification "was changed from: Jervis B. Webb Company on 01‑08‑2024" and "Converted from Jervis B. Webb Company on 03‑20‑2020" (https://business.sos.ri.gov/CorpWeb/CorpSearch/CorpSummary.aspx?FEIN=001706229&SEARCH_TYPE=3). No bankruptcy, receivership, or dissolution of the original assignee is evidenced in any source located.

Assignment timeline

The Assignment Center / Google Patents legal-events record for US 4,464,997 contains exactly one recorded assignment, and it is the pre-issuance inventor-to-employer conveyance. There are no post-issuance assignments, no security interests, no merger records, and no change-of-name records filed against this patent number.

• 1982‑07‑16 (executed / effective date) / recorded 1982‑07‑26 — Reel 004025 / Frame 0272
  • Conveyance: Assignment — "ASSIGNMENT OF ASSIGNORS INTEREST."
  • Assignor: Dehne, Clarence A. (sole inventor)
  • Assignee: Jervis B. Webb Company, a corporation of Michigan ("JERVIS B WEBB COMPANY A CORP OF MI")
  • Correspondent: Not determinable from the records available to me. The indexed legal-event text stops at "…ASSIGNOR, DEHNE, CLARENCE A.;REEL/FRAME:004025/0272" and does not expose a correspondent attorney or firm. Obtaining the correspondent of record would require pulling the assignment image itself from the Assignment Center. I am not going to guess at a name here, and I flag this as an open item rather than a finding — an absent correspondent reference in the index is not evidence of a repeat-player attorney.
  • Context: Ordinary employee-inventor assignment to employer, executed ten days before recording and on the same day (1982‑07‑26) as the application filing. Textbook pre-issuance title-clearing, not an acquisition or transfer of a portfolio.

Two ownership-affecting corporate events exist that are NOT patent assignments and do not appear in this patent's legal-events record:

1. 2007 (~Nov 15 agreement; December 2007 close) — share purchase of Webb by Daifuku Co., Ltd. This was a purchase of 100% of Webb's shares, so title to Webb's patents remained inside the surviving corporation. No assignment recordal is legally required or expected, and indeed none appears. Do not mistake this blank for a gap in the record.
2. 2024‑01‑01 — change of name, Jervis B. Webb Company → Daifuku Airport America Corporation. A pure name change; the legal entity and its title to the patent are unchanged. No "Change of Name" assignment record appears against US 4,464,997 in the indexed legal events, which is consistent with the entity surviving under its new name.

Maintenance-fee and status events (not assignments, listed to complete the chronology): FEPP 1986‑12‑05; FPAY year 4 — 1987‑09‑14; FPAY year 8 — 1991‑12‑09; FEPP 1995‑12‑03; FPAY year 12 — 1996‑02‑14. Anticipated expiration 2002‑01‑18; status Expired – Lifetime. No 16-year maintenance-fee payment appears, consistent with expiry at the end of the statutory term rather than a lapse for non-payment.

Timeline diagram

timeline
    title Ownership of US 4464997
    1982 : Inventor assignment executed
         : Recorded reel 004025 frame 0272
         : CIP filed as Ser 06/401924
    1984 : Patent issued to Jervis B Webb Company
    2002 : Patent term expired
    2007 : Webb shares sold to Daifuku Co Ltd
    2024 : Webb renamed Daifuku Airport America

NPE / troll-pattern signals

Verdict

Insufficient data — taken literally as the rubric defines it: there are no records beyond the original assignment. This is the "only the original assignment" branch, not a finding of ambiguity about who owns the patent.

Justification: the sole recorded conveyance is Reel 004025/0272, executed 1982‑07‑16 and recorded 1982‑07‑26, an inventor-to-employer assignment of interest from Clarence A. Dehne to Jervis B. Webb Company — a pre-issuance, title-clearing transaction with zero NPE characteristics. Every subsequent ownership-relevant event (Daifuku's December 2007 share purchase of Webb, and the 2024‑01‑01 renaming to Daifuku Airport America Corporation) occurred at the corporate level inside a surviving operating entity, and none of them is an assignment recorded against this patent. The substantive conclusion that accompanies the "insufficient data" label is therefore no NPE chain of any kind: the patent was owned by its operating-company employer from 1982 until it expired on 2002‑01‑18, and it is now a lapsed, publicly readable document with no assertion history.

Verification link: USPTO Assignment Center — https://assignmentcenter.uspto.gov/ (search patent number 4464997); mirror index at https://assignment.uspto.gov/patent/index.html. Patent-level record: https://patents.google.com/patent/US4464997/en.

Open items / limitations, stated plainly:

• The correspondent of record on Reel 004025/0272 is not retrievable from the indexed data I could access. I did not fabricate one. If you need it, pull the assignment image from the Assignment Center; a 1982 Webb filing would most likely have been recorded by in-house or Detroit-area counsel, but that is a hypothesis, not a finding, and I am not entering it into the record.
• I could not visually confirm the Assignment Center's own display for this patent number (the search returned only the Google Patents / uspto.report legal-events text plus uspto.report's grant page at https://uspto.report/patent/grant/4,464,997). The record is unambiguous that only one assignment exists, but a belt-and-suspenders check of the Assignment Center UI is the definitive step.
• Contradiction check against the earlier sections: none found. The prior litigation analysis concluded "no known or reported litigation," which is consistent with — and here explained by — a single 1982 assignment to an operating manufacturer and an expiration in 2002. The earlier flag that EP 0 872 218 B1's "US 4464997 P" is provisional application 60/044,997 (a different identifier) also stands; it has no bearing on this assignment chain.

I'll verify the USPTO record for 4464997 and then research each cited prior-art reference individually.

Prior-Art Analysis — US 4,464,997 (Conveyor Trolley and Track)

0. Verification of the record (searched patent number 4464997 only)

The search for US 4,464,997 returned the expected grant record; I did not substitute any similar number. Confirmed from the Google Patents, Justia, and uspto.report pages (all three resolve to the same document):

Sources: https://patents.google.com/patent/US4464997/en ; https://patents.justia.com/patent/4464997 ; https://uspto.report/patent/grant/4,464,997

Critical framing point before the per-reference review. Both independent claims are drafted in Jepson/improvement format. The preamble of claim 1 recites the trolley body, wheel pairs, guide rollers, and the shield member ("a shield member formed on the body disposed outwardly of and adjacent to the guide rollers… having portions which project longitudinally and transversely outwardly of the peripheries of the guide rollers"). That preamble structure is therefore admitted prior art. The sole characterizing improvement of claim 1 is the socket closed by the shield member + driving‑dog stem + means supporting the stem. Claim 10 is the same characterization, narrowed to the wear‑plate/roller/axle stem‑support subassembly. This matters for § 102: a reference that shows only the admitted preamble (trolley + wheels + guide rollers + shield) cannot anticipate either independent claim.

---

1. The 12 references cited on the face of US 4,464,997

All twelve predate the earliest possible date (1982‑01‑18) and are therefore § 102(b)/§ 102(a)-eligible as printed publications. Dates below are the priority/issue dates as they appear in the '997 citation record; where a source contradicted the priority date I say so.

1.1 US 1,920,774 A — Webb, "Trolley for conveyer systems"

• Full citation: US 1,920,774 A; filed Nov. 2, 1931 (Ser. No. 572,806); patented Aug. 1, 1933; inventor Jervis B. Webb, Royal Oak, Mich.; 1 claim; class B65G 17/20. (Cited on the '997 face; same assignee family as the '997.)
• Description (verified): A load‑carrying conveyor trolley that eliminates flanged wheels by combining horizontal running wheels with vertical auxiliary rollers ("no danger… broken or chipped flanges"; "use therefore of flangeless wheels and vertical rollers assures quiet and easy operation"). The vertical rollers prevent lateral movement of the trolley on the trackway; the trolley head is engaged by a chain dog. Source: https://www.freepatentsonline.com/[1920774](/patent/1920774).html and the Google Patents text.
• § 102 relevance: This is the closest cited reference to the guide‑roller aspect of the preamble (perpendicular vertical guide rollers co‑operating with flangeless running wheels). It does not disclose a socket, a shield‑member‑closed end, or a stem‑supported driving dog.
• Potentially anticipates: No claim. At most it is § 103 background against the preamble of claims 1/10 (which is admitted prior art anyway).

1.2 US 2,043,357 A — Strauss, "Truck for air tramways"

• Full citation: US 2,043,357 A; priority 1931‑08‑12; published Jun. 9, 1936; Joseph B. Strauss.
• Description: Air‑tramway carriage/truck (a suspended‑vehicle trolley). I did not retrieve the full text in this pass; the title/assignee are confirmed, the internal disclosure is not independently verified here.
• § 102 relevance: General suspended‑trolley art; no indication of a dog‑socket or shield. Potentially anticipates: No claim (not verifiable as to the characterizing elements).

1.3 CA 516,865 A — M. King, "Conveyors"

• Full citation: CA 516,865 A; published Sep. 27, 1955; M. King (Donald).
• Description: Canadian conveyor patent; text not retrieved. Title/date only confirmed.
• § 102 relevance: Generic conveyor art. No anticipation of claims 1/10 on the record.

1.4 GB 987,097 A — Tissmetal Lionel Dupont Teste, "Improvements in conveyors"

• Full citation: GB 987,097 A; priority 1960‑06‑09; published Mar. 24, 1965.
• Description: Text not retrieved; classified as conveyor improvements. § 102: No anticipation of the socket/shield characterization.

1.5 US 3,229,645 A — Jervis B. Webb Co., "Power and free conveyors"

• Full citation: US 3,229,645 A; priority 1964‑03‑12; patented Jan. 18, 1966; assignee Webb Co., Jervis B.; inventor family of the '997's own assignee.
• Description (verified from the patent PDF and the Webb v. Southern opinion): A power‑and‑free conveyor with load carriers each having a forward trolley carrying a main one‑way driving dog 34 and a spring‑loaded holdback dog 40, and a rear trolley with a supplementary driving dog 42. The stop arrangement uses a stop plate that engages the holdback dog; pusher engagement is controlled by changing the spacing between power and load tracks. The specification of the '997 expressly incorporates this patent as an example of the load carriers to which its trolley applies.
• § 102 relevance: Directly relevant to the movable driving/holdback dog concepts underlying claims 1, 7 and 10. It shows dogs pivotally mounted on the trolley, not a dog stem sliding inside a body socket, and no shield‑closed socket.
• Potentially anticipates: No claim; strong § 103 reference as to the driving‑dog element. (Note: the '645 was one of the two references that was before the examiner in the separate Webb v. Southern case on the '352 patent — see § 3.)

1.6 US 3,418,948 A — Fromme Förderanlagen GmbH, "Chain driven conveyor system having driving members"

• Full citation: US 3,418,948 A; German priority Feb. 23, 1966; U.S. filing Feb. 20, 1967 (Ser. No. 617,258); patented Dec. 31, 1968; assignee Fromme Förderanlagen GmbH; class B61B 10/02.
• Description (verified): A chain‑driven conveyor in which the pusher/driving member is movable between retracted and extended positions (the "cam on the carrier" alternative referred to in later Webb patents, e.g., US 3,559,585, which cites "U.S. Pats. Nos. 3,418,948 and 3,418,949"). Source: https://www.freepatentsonline.com/3418948.html ; US 3,559,585 text.
• § 102 relevance: Relevant to the concept of a driving member movable between extended/retracted positions (claims 1, 7, 10, 12). It does not show a body socket closed by a shield member.
• Potentially anticipates: No claim.

1.7 US 3,375,790 A — Mechanical Handling Systems, Inc. (Bishop), "Articulated carrier for power and free conveyor systems"

• Full citation: US 3,375,790 A; filed Mar. 14, 1966 (Ser. No. 534,051); patented Apr. 2, 1968; inventor Leonard J. Bishop; assignee Mechanical Handling Systems, Inc., Warren, Mich.; 6 claims; class 104/172.
• Description (verified): An articulated multi‑trolley carrier for power‑and‑free systems. The leading trolley has a pusher dog 13 retractable by a pivoted lever 19 that engages an inclined surface on the preceding carrier's rear trolley, moving the dog out of the pusher path. The patent is expressly noted as being "self cleaning… can be used in corrosive or contaminating environments." The '997 specification cites this patent as an example of a suitable load carrier.
• § 102 relevance: Most relevant to the retractable driving dog limitation (claims 1, 3, 7, 10, 12) and, anthropomorphically, to the contamination‑resistance motivation. Still no shield‑closed socket.
• Potentially anticipates: No claim.

1.8 FR 1,516,520 A — Geo W. King Ltd., "Load transport trolley applicable to a transport installation"

• Full citation: FR 1,516,520 A; priority 1966‑03‑17; published Mar. 8, 1968.
• Description: French trolley patent; text not retrieved beyond title. § 102: No anticipation on the record.

1.9 CA 756,365 A — J. B. Orwin (Olaf), "Conveyors for conveying goods"

• Full citation: CA 756,365 A; published Apr. 11, 1967; J. B. Orwin.
• Description: Canadian conveyor patent; text not retrieved.
• § 102 relevance: Flag for follow‑up: the name Orwin is the same inventor surname attached to the "British Orwin patent" that was the most relevant prior art in Jervis B. Webb Co. v. Southern Systems, Inc. (see § 3). Whether CA 756,365 is a counterpart of GB 819,343 / GB 819,848 is not established here and I do not assert it. If it is, it would be highly material to the driving‑dog claims. I state this as an unresolved lead, not a finding.

1.10 GB 1,263,299 A — American Chain & Cable Co., "Improvements in trucks for use in accumulating tow truck conveyor systems"

• Full citation: GB 1,263,299 A; priority 1969‑07‑14; published Feb. 9, 1972.
• Description: Tow‑truck accumulating conveyor trucks; text not retrieved. § 102: No anticipation of the socket characterization on the record.

1.11 US 3,882,793 A — Nakanishi Metal Works Co., "Tow conveyor"

• Full citation: US 3,882,793 A; priority 1972‑07‑10; patented May 13, 1975; assignee Nakanishi Metal Works Co.
• Description: Tow conveyor (dog‑driven truck) art; full text not retrieved.
• § 102 relevance: Potentially relevant to dog/tow‑pin mounting and track construction; I could not verify whether any dog is mounted in a body socket. Potentially anticipates: No claim verified; treat as § 103 background only.

1.12 US 3,869,989 A — Redman Fisher Engineering Ltd., "Conveyor"

• Full citation: US 3,869,989 A; priority 1973‑03‑30; patented Mar. 11, 1975; assignee Redman Fisher Eng. Ltd.
• Description: Conveyor patent; full text not retrieved. § 102: No anticipation on the record.

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2. The two references expressly named in the '997 specification (same list)

The description of the '997 states: "Examples of such load carriers for overhead power and free conveyors may be found in U.S. Pat. Nos. 3,229,645 and 3,375,790 to which reference is made." Both are already counted above (items 1.5 and 1.7). Neither shows the characterizing socket of claims 1/10. They are, however, the two references the patentee itself adopted as the closest known load‑carrier art — useful for construing the preamble and for any § 103 combination.

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3. Relevant art not on the '997 face but in the same technical lineage (context, not § 102 against the '997)

These are not cited on the '997 and cannot, on their own, be § 102 art against a 1982‑priority case unless their dates qualify — but they are directly relevant background and clarify what the '997 was doing:

• US 3,451,352 / US 4,274,352 (Webb) — the driving‑dog patent litigated in Jervis B. Webb Co. v. Southern Systems, Inc., 742 F.2d 1388, 222 USPQ 943 (Fed. Cir. Aug. 16, 1984) (https://law.justia.com/cases/federal/appellate-courts/F2/742/1388/[212979](/patent/212979)/). The Federal Circuit held claims 1, 3, 4, 8, 9, 11 invalid for obviousness over, inter alia, U.S. 2,883,942 and the British Orwin patent (GB 819,343), with the examiner‑considered US 3,229,645 supplying the supplementary‑dog teaching. This is the same dog‑and‑pusher subject matter as claims 1/7/10/12 of the '997, and it shows the field was crowded with cam‑actuated, mass‑biased, retractable dog teachings.
• US 3,559,585 (Webb) — movable pusher/accumulation power‑and‑free art; expressly cites US 3,418,948 (item 1.6) and German 1,143,499 for cam‑actuated dogs.
• Later Webb patents citing the '997 as their prior art (forward citations, not anticipation): US 4,616,570 (1986), US 4,745,865 (1988, Dehne). These confirm the '997's socket/shield design was itself treated as background for a later generation of Webb trolleys.

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4. Bottom-line § 102 assessment

Most relevant prior art overall: For the driving‑dog aspect (claims 1, 3, 7, 8, 10, 12, 13), the closest cited references are US 3,229,645 (Webb), US 3,418,948 (Fromme) and US 3,375,790 (Mechanical Handling Systems) — all showing dogs movable between extended and retracted positions, with gravity/cam biasing. For the trolley/guide‑roller aspect (admitted preamble), the closest is US 1,920,774 (Webb).

No single cited reference appears to anticipate claim 1 or claim 10, because the distinguishing feature the '997 claims as its invention — a body socket, centered between the wheel pairs and capped by the shield member, into which the driving‑dog stem extends and is supported by rollers and wear plates — does not appear in any reference on the face of the patent. On this record the cited art is best characterized as § 103 background, not § 102 anticipation. This is consistent with the fact that the '997 issued with 13 claims and was never invalidated.

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5. Confidence and limitations

• High confidence in the bibliographic data and in the text of the four references I retrieved in full (US 1,920,774, US 3,229,645, US 3,418,948, US 3,375,790) and in the Webb v. Southern decision.
• Lower confidence / explicitly flagged: I did not retrieve the internal disclosures of US 2,043,357, CA 516,865, CA 756,365, GB 987,097, FR 1,516,520, GB 1,263,299, US 3,882,793, US 3,869,989. My § 102 conclusions for those eight rest on title, assignee, date and class only, and are stated as "no anticipation on the record," not as affirmative clearances. Each would need its full text pulled before any anticipation position is asserted against the '997.
• Open lead: the possible relationship between CA 756,365 (Orwin) and the British Orwin GB 819,343 reference that was decisive against Webb's '352 patent in Webb v. Southern is unverified; I flag it rather than assert it.
• The characterizations of claim 1 and claim 10 scopes, and the "admitted prior art / Jepson preamble" observation, follow directly from the claim text you supplied; the antecedent‑basis gap in claim 10 (its preamble recites wheels but its body recites "the axes of the guide rollers") was already noted in the previously generated section and is not contradicted here.

I'll verify the key references before building the § 103 combinations, focusing on the ones the Prior Art section flagged as un-retrieved or as lineage art.

Let me confirm the '942 reference's details and probe for art showing a sliding dog stem in a body socket with roller support.

Obviousness Analysis — US 4,464,997 under 35 U.S.C. § 103

Building on the Prior Art section: that section concluded no single reference anticipates claims 1 or 10 and characterized the cited art as "§ 103 background." This section takes that conclusion as the starting point and does the § 103 work. It also adds one reference the Prior Art section only flagged as lineage art — US 2,883,942 (the '942 patent) — which I retrieved in full and which materially changes the strength of the obviousness case. Two flags carry forward: the unresolved Orwin lead (CA 756,365 vs. GB 819,343), and the claim 10 antecedent-basis gap. No contradictions with the earlier sections found.

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1. Bottom line up front

Overall: the '997 is a structurally narrow improvement over a very crowded art. Independent claim 1 is the vulnerable claim, not because any reference shows the whole thing, but because each of its parts was old and the combination was a predictable design choice driven by a problem the art had already identified. Claim 10's roller/slot/wear-plate sub-assembly is the single link with no clear on-face disclosure, and it is where a validity defense should be fought.

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2. Threshold findings that drive the whole analysis

(a) Level of ordinary skill. In the one adjudicated case on this family the factfinder held a person of ordinary skill in this field "would have been a conveyor designer." Jervis B. Webb Co. v. Southern Systems, Inc., 742 F.2d 1388 (Fed. Cir. 1984) (casetext, CourtListener). That is a mechanical-arts, whole-trolley level of skill — not a specialist in guide-roller tribology. A skilled designer will be presumed to know how to mount a dog in a trolley body, how to bias one by gravity, and how to guide a reciprocating member with rollers in slots.

(b) Effective date. 1982-01-18 (CIP parent Ser. No. 06/340,112). Everything in the arsenal predates 1975 and therefore qualifies as § 102(b) printed publication art.

(c) The Jepson admission is the single most important fact. The preamble of claim 1 (and the parallel structure in claim 10's conveyor preamble) recites the trolley body, the wheel pairs, the guide rollers, and the shield member — "a shield member formed on the body disposed outwardly of and adjacent to the guide rollers, the shield member extending perpendicular to the axes of the guide rollers and having portions which project longitudinally and transversely outwardly of the peripheries of the guide rollers." Under the improvement-claim format, that structure is admitted prior art. The patentee cannot argue that the shield itself, or its overlap of the guide track surfaces, was inventive. The only thing claim 1 adds is: put a socket in the body between the wheels, center it, run it parallel to the guide-roller axes, cap its far end with the shield that is already there, and drop the driving dog's stem into it.

(d) "Means supporting the stem portion" is a means-plus-function limitation. Claim 1's third characterizing element is purely functional. Under § 112(f) it is limited to the corresponding structure in the specification (rollers 63/64 on axles 65/66, slots 67/71, wear plates 68/69) and equivalents. This narrows claim 1 for infringement but also makes it easier to read the '942's pin-and-stop mounting onto it as an equivalent — a two-edged sword the patent owner must live with.

(e) Claim 10's antecedent gap (carried forward from the Prior Art section). Claim 10's preamble recites supporting wheels but not guide rollers, yet its body recites a socket "extend[ing] substantially parallel to the axes of the guide rollers." Either (i) the claim is construed to require guide rollers (importing them by implication), which pulls in the '774/'997-preamble guide-roller art, or (ii) it is indefinite under § 112(b). Either way it does not help the patent owner.

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3. The prior-art arsenal, element-by-element

The '942 patent — the reference the Prior Art section did not retrieve

I pulled this one because the Prior Art section flagged the lineage. It is decisive for motivation purposes:

"lower sections of parts 8 and 9 are spaced apart so as to define an aperture or housing having side walls 13 and 14, respectively, through which a trolley advancing means or drive element, such as a chain 15, may extend… the pin members 10 and 11 provide pivots for a drive dog member 26 and a hold back dog member 27… These dog members are normally urged toward the trolley aperture by gravity, and their movement is limited by a stop pin 28 mounted in the side part 9 of the trolley… Each trolley has a guide shoe 34 extending beneath and beyond the aperture…"
— US 2,883,942 (PDF: patentimages)

That is, in 1950s Webb-family art: a trolley body with a recess between its wheel-carrying horns, a dog mounted in that recess on transverse pins, biased to its operative position by its own mass, with travel limited by a stop, and with a separate replaceable shoe at the mouth of the recess. The '997's claim 1 socket/stem/means is an obvious modernization of this — with the addition of a cover the '997 itself concedes was old.

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4. Ground 1 — Claim 1 (and dependent claims 7, 12)

Combination: '942 + '774, in view of the shield member admitted in the '997 preamble (optionally + '645 or '948).

Motivation to combine (the required "articulated reasoning"):

1. Same field, same problem, same family. Both are overhead/tow conveyor trolleys in which a dog on the trolley is engaged by a moving element. The '942 was before the examiner in the '352 prosecution; it is the same art the patentee itself was working in. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 417 (2007) ("if a technique has been used to improve one device… a court must ask whether the improvement is more than the predictable use of prior art elements according to their established functions").
2. The problem was known and the solution was a design need. The '997's stated problem is contamination, spray, foreign objects and sabotage in power-and-free conveyors with the power track below the track. That problem is recited as already recognized in the art — US 3,375,790 touts a carrier that is "self cleaning… can be used in corrosive or contaminating environments." Enclosing a dog recess that the '942 already provides, and capping it with a shield the preamble already provides, is a predictable answer to a known need.
3. No new mechanism is required. Claim 1 adds no new part. It takes the '942's body recess, keeps the dog inside it, and puts the admitted shield over the top. That is "the mere rearrangement of parts" / "change in shape" territory under § 103.
4. No teaching away. Nothing in '942, '774, '645, '790 or '948 criticizes enclosing a dog in a body recess. The '942's guide shoe 34, which extends "beneath and beyond the aperture," points toward body-mounted shrouding of the aperture mouth.

Dependent claims 7 and 12 (open end directed toward the supporting track surfaces; dog biased to the extended position by its mass): these are the most obviously anticipated-in-substance limitations in the patent. The '942 recites in terms that its "dog members are normally urged toward the trolley aperture by gravity" and that "the pusher 35, pusher tilting dogs 36 and reverse travel preventing dog 41 remain in upright position by virtue of the weight of portions thereof lower than the pivots" (US 3,882,793, Google Patents). Gravity-biasing of a conveyor dog is about as settled as an art can get, and Webb itself had litigated and lost on counterweighted-dog claims on the '352. Because claims 7 and 12 depend from claims 1 and 10, they cannot be independently valid if the parents fall, and their added limitations add nothing.

Anticipation caveat (consistent with the Prior Art section): I do not assert § 102 against claim 1. The '942's dog pivots; the '997 claims a stem in a socket. That difference is why this is a § 103 case with '942 as the primary reference, and it is also precisely the difference that KSR and In re Keller treat as a predictable mechanical variation rather than an inventive step.

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5. Ground 2 — Dependent claims 2, 3, 4, 5, 6, 8, 9 (the roller/slot/wear-plate support)

Combination: '942 + '774 + one of '948 / '645 (+ '237), in view of ordinary mechanical skill.

The specific structure is: rollers (63/64) on axle members (65/66) extending transversely through the socket and spaced lengthwise of it; slots (67/71) on the stem engaging the rollers; transversely spaced wear plates (68/69) on those axles, slidably engaged by the stem.

What the art supplies:

• Transverse axle members passed through the trolley body at the dog recess — directly taught by '942 (pin members 10, 11; stop pin 28 "mounted in the side part 9 of the trolley"; pins 71/75 and 78/80 in the Fig. 5 embodiment).
• Limit/stop structure interacting with a dog's travel — '942's stop pin 28. Claim 13's "slot means and rollers defining the extended position" is the same function by a different, well-known expedient.
• A separate, replaceable wear element mounted on the trolley body at the mouth of the recess — '942's guide shoe 34, "extending beneath and beyond the aperture to properly guide the chain." The '997's wear plates 68/69 are the same idea (take the sliding wear in a replaceable insert so the body bore needs no machining) expressed as a pair of plates on a transverse axle. Claim 6/11's "wear plates attached to the axle member" is a mounting-location choice with no asserted advantage.
• Rollers as a substitute for sliding contact — ubiquitous in the art. The '942 and '793 both use rollers on axles; '948/'645/'790 all use pinned, movable dogs.

Motivation to combine:

1. Substitution of a known equivalent. Converting sliding engagement to rolling contact (roller-in-slot rather than pin-in-slot or pin-in-bore) is a classic fatigue/wear-reduction substitution, and the '997 articulates no result beyond reduced friction and the ability to skip boring the socket. "[W]hen a patent 'simply arranges old elements with each performing the same function it had been known to perform' and yields no more than one would expect from such an arrangement, the combination is obvious." KSR, 550 U.S. at 417.
2. The stated advantage is a manufacturing convenience, not a technical result. The '997 spec says the wear-plate construction "makes it unnecessary to internally machine the socket 44." Eliminating a machining operation by inserting a wear liner is precisely the kind of "design incentive[]… motivated by the desire to… reduce manufacturing cost" that the case law treats as obviousness evidence.
3. Reasonable expectation of success is high. Every one of rollers-on-transverse-axles, slots-as-stops, and replaceable liners was individually known and used for the same purposes.

Where this ground is weakest — and it is the honest weak link: I found no reference, on the '997 face or off it, that shows a dog stem sliding in a socket on rollers captured in slots, with side wear plates. The '942's dog pivots; the '948/'645/'790 dogs pivot or are cammed; the '793 pusher pivots. A patent owner will argue that the "socket + sliding stem + roller/wear-plate cartridge" was a genuine structural departure that the art did not suggest, and that no reference even presents the problem (sliding-stem dog) the solution addresses. That is a real argument, and it is why the verdict below is "moderate," not "high," for these claims. But countering it is the KSR "predictable variation" and "known technique to improve a similar device" reasoning, plus the point that claim 1's "means" limitation was deliberately drafted in functional terms precisely to cover equivalents.

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6. Ground 3 — Claim 10 (and dependencies 11, 13)

Combination: '942 + '774 + '948 (or '645) + the admitted shield, with the '942 guide shoe / '237 wear-element teaching supplying the wear plates.

Claim 10 is claim 1 with the support means committed to structure: wear plates spaced transversely of the socket and slidably engaged by the stem, plus a plurality of rollers engaged by the stem mounted between the wear plates on axle members extending transversely of the socket and spaced apart lengthwise.

• The track + wheels preamble: '774/'645/'997 preamble.
• Integrally formed socket between the wheel-pair axes, centered, open end and closed end: '942 aperture/housing; integration of body casting is the '997's ordinary design choice (and the '997's own body is a casting with integral shield per its preamble).
• Stem in the socket; rollers engaging it on transverse axles; plates engaged by the stem: '942's transverse pins plus replaceable show; '237/'793's axle-mounted rollers on a trolley body.
• Open end toward the supporting track surfaces and mass-biasing (claim 12): '942 and '793, as above.

Motivation: identical to Grounds 1 and 2, and reinforced by the fact that claim 10's socket is recited as integrally formed — which is exactly what the '942's two-piece trolley body already was (the aperture is formed by the trolley body parts themselves, "lower sections of parts 8 and 9 are spaced apart so as to define an aperture or housing"). There is no patentable weight in saying the recess is cast into the body rather than defined between two bolted halves.

Note the practical irony: claim 10 is probably less likely to be invalidated than claim 1, because it is narrower. But it is also probably less likely to be infringed by anyone, because it is narrower. An expired claim that is hard to invalidate and harder to infringe is worth nothing to either side.

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7. The motivation-to-combine toolkit (rationales with record support)

Rationale #6 deserves emphasis. In Webb v. Southern, the Federal Circuit held that the British Orwin patent's own teaching of reversing the drive and driven elements "cannot form a basis for a holding of unobviousness." The same logic applies here: the art treated the mounting location of the dog (trolley vs. chain, body vs. recess) as a matter of design, not invention.

And the unresolved lead carried forward from the Prior Art section: CA 756,365 A (Orwin, 1967) is on the '997 face. If it turns out to be the Canadian counterpart of GB 819,343 — the reference the Southern Systems court found disclosed all the elements of the '352's broadest claim — then a genuinely anticipatory-or-near-anticipatory reference on the '997's own face becomes a live issue, and the motivation analysis gets even easier. I do not assert the relationship; it needs a document pull.

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8. Secondary considerations — the patent owner's rebuttal case (and why it likely fails)

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9. The patent owner's strongest counterarguments (stated fairly)

1. No reference shows the sliding-stem-in-a-socket. Every dog in the art pivots or is cammed; none slides linearly on rollers inside a body bore. If the patent owner can show that the sliding stem was itself a solution to a different problem the art had not identified (e.g., vertical space constraints under the power track, or the need for a dog that retracts axially rather than swinging), the nonobviousness argument gains traction.
2. No articulated motivation to combine '942 with '774. A challenger must supply a reason, not just a roster of parts. ACS Hosp. Sys. v. Montefiore Hosp., 732 F.2d 1572 (Fed. Cir. 1984) (teaching or suggestion supporting the combination required). Here the reason is the contamination problem stated in the '997's own background — a two-edged sword, since using the patent's own problem statement as the motivation risks hindsight. I acknowledge that risk: the challenger should ground the motivation in '790's pre-existing self-cleaning/corrosive-environment disclosure and in '942's guide shoe, not in the '997's prose.
3. Hindsight reconstruction. Picking '942 (a tow/grouping conveyor) and '774 (a 1933 trolley) and assembling them may be attacked as "pick[ing] and choos[ing] among isolated disclosures in the prior art." That is the standard defense, and it is the reason the claim-by-claim verdicts above are nuanced rather than uniform.
4. Claim 10's specificity. The narrower independent claim commits to the wear-plate-and-multiple-roller cartridge and is the best candidate for survival.

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10. Verdict

• Claims 1, 7, 12 — more likely than not obvious over US 2,883,942 in view of US 1,920,774, the shield being admitted prior art. The '942's body recess, gravity-biased dog, transverse pin mounting, stop pin and aperture-mouth guide shoe do the heavy lifting; the admitted shield supplies the "closed end."
• Claims 2, 3, 8, 13 — moderately vulnerable; the roller/slot support is a known expedient applied to a known problem, but there is no direct disclosure of a roller-supported sliding dog stem, and the challenger must carry the motivation burden with non-hindsight evidence.
• Claims 4, 5, 6, 9, 11 — moderately vulnerable; wear plates are the replaceable-liner equivalent of '942's guide shoe, and "attached to the axle member" (claims 6, 11) is a mounting detail with no asserted effect.
• Claim 10 — the patent owner's best claim; its committed structure is not shown in the located art, and its antecedent-basis gap argues for a construction either narrow (importing guide rollers and thus requiring the '774 art) or indefinite (§ 112(b)). Neither construction helps it much, but together they make claim 10 the last line of defense.

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11. Practical significance — and two things not to lose sight of

The § 103 analysis is now academic for enforcement purposes. US 4,464,997 expired on 2002-01-18 ("Expired – Lifetime," anticipated expiration; Google Patents legal events). Under 35 U.S.C. § 286 the damages lookback on today's date runs to 2020-09-30 — every day of which postdates expiry. No infringement theory survives that. Nothing in this obviousness analysis can or should be used to revive a damages claim, and no IPR would be worth filing (see the PTAB section).

Where this analysis does have value: (a) as prior-art characterization if someone ever asserts a later, unexpired member of this lineage; (b) as a defensive record if a patent owner asserts the '997's foreign counterparts in a jurisdiction where they remain enforceable — the same § 103 reasoning travels, and the '942/'774 combination is available art in all of them; and (c) as a caution about the family — Webb lost the '352 patent's broad dog claims on obviousness over essentially this art, and the '997 claims the same functional territory through a different structural doorway.

Limitations, stated plainly. I did not retrieve the internal disclosures of US 2,043,357, CA 516,865, CA 756,365, GB 987,097, FR 1,516,520, GB 1,263,299, or US 3,869,989 (inherited from the Prior Art section), and I did not verify the CA 756,365 ↔ GB 819,343 relationship. I verified the full text of US 2,883,942, US 1,920,774, US 3,229,645, US 3,418,948, US 3,375,790, US 3,882,793 and the Webb v. Southern opinion. My confidence is high in the claim 1/7/12 analysis, moderate in the claim 3/5/6/8/9 analysis, and low-to-moderate on claim 10 — and this is a paper § 103 assessment, not a legal opinion or a validity determination.