US 5863470

I'll search for authoritative information on US 5863470, including any 2026 CAFC activity.

Let me check for any litigation or enforcement activity involving this specific patent.

US Patent 5,863,470 — Search Results

Note on scope: I searched for the exact number 5863470 (US 5,863,470). I found authoritative bibliographic and full-text data, but no CAFC 2026 docket activity naming this patent. A generic search for "5863470" also surfaced unrelated hits (e.g., OSTI ID 5863470 for an oil-recovery method; JP 5863470 for a window sash; a Chinese UWSN patent listing) — these are different identifiers and I have not confused them with the US patent.

Bibliographic data

Abstract (as printed)

Venturi sleeves (24, 26, 28 and 30) are telescopically moved upwardly into the bores (14, 16, 18 and 20) of the carburetor body (12) until the annular shoulder (46) of each sleeve abuts a corresponding shoulder (36) of each bore. Booster venturis (74, 76, 78 and 80) are suspended coaxially with respect to the venturi sleeves (24–30) with the support conduit (86) extending through a notch (52) at the first edge of the venturi sleeve. Positioning cords (50) are formed in the lower outer cylindrical surface (44) of each venturi sleeve (24), so that the positioning cords (50) must face and abut each other when the venturi sleeves are properly inserted into the bores of the carburetor body, thus assuring that the sleeves are properly oriented in the carburetor body. Flow director surfaces (104, 106, 108 and 110) in the carburetor bowl (102) guide the air toward the venturi sleeves.

Plain-language overview of the independent claims

The patent has 19 claims, of which claims 1, 2, 3, 6, 13, 15, and 17 are independent. Claims 4–5 depend on 3; 7–12 depend on 6; 14 depends on 13; 16 depends on 15; 18–19 depend on 17.

• Claim 1 — Carburetor with drop-in venturi sleeves (4-barrel). A carburetor body with four open-ended bores. Each bore has an upper cylindrical section, a wider lower cylindrical section, and an internal shoulder between them. A removable venturi sleeve sits in each bore, its outer surfaces matching the bore's two diameters, with an external shoulder resting on the bore's shoulder so the sleeve seats at a fixed depth. Each sleeve has a full venturi passage (converging inlet → wall constriction → diverging outlet) that creates a low-pressure zone. The body's air-inlet manifold bowl's interior defines concave flow director surfaces surrounding each bore and substantially coextensive with the sleeves' converging inlet surfaces. A retainer/holding means (the base plate) locks the sleeves in place. Core idea: a mass-producible carburetor body that accepts machined, interchangeable venturi inserts, with the bowl contoured to feed them smoothly.

• Claim 2 — Manifold-bowl geometry focus. Same general sleeve-in-bore arrangement, but the emphasis is on the inlet manifold bowl's concave flow director surfaces: each concave surface surrounds and intersects one bore, adjacent concave surfaces are separated by ridges running between them, and the surfaces are substantially coextensive with the sleeves' converging inlets to improve airflow about the inlet ends of the venturi throats.

• Claim 3 — Venturi throats in the body (no sleeve required). A carburetor body with an air-inlet bowl and at least two side-by-side parallel open-ended venturi throats intersecting the bowl. Each throat has a converging inlet, a diverging outlet, and a wall constriction generating a low-pressure zone. The bowl's interior has contoured flow director surfaces, each surrounding/intersecting one throat and substantially coextensive with that throat's converging surface to smoothly guide air in. This claim is drafted broadly enough to cover a carburetor without the removable sleeves.

• Claim 6 — Sleeve-alignment feature. A carburetor body with multiple open-ended bores (two-diameter, shouldered). A venturi sleeve in each bore with matching stepped outer surfaces and a shoulder abutting the bore shoulder. The key added element is alignment means formed in the lower outer cylindrical surface for engaging and aligning with an adjacent venturi sleeve. Each sleeve has a venturi passage with a pressure-generating constriction, plus holding means. This is the claim directed to the anti-rotation/inter-sleeve alignment concept (the "positioning cord" of claim 8).

• Claim 13 — Four-throat rectangular-cluster assembly. A body with four open-ended venturi throats arranged parallel in a rectangular cluster, each with an annular converging inlet intersecting the manifold bowl. The bowl has a perimeter rim and plurality of concave contoured interior surfaces, each surrounding one throat and coextensive with its converging inlet, with ridges between the concave surfaces separating them and guiding air. Focused on the multi-throat bowl-manifold geometry.

• Claim 15 — The venturi sleeve as an article of manufacture. A standalone venturi sleeve comprising: an upper outer cylindrical surface; a larger-diameter lower outer cylindrical surface; an external annular shoulder joining them; a positioning cord formed in the lower cylindrical surface for engaging a like positioning cord of an adjacent sleeve; and an internal open-ended venturi passage (first end, second end, wall constriction generating a low-pressure zone). This is the "replacement part" claim — it protects the sleeve itself, independent of the carburetor.

• Claim 17 — Bowl contour for air-filter mounting. A carburetor body with parallel clustered open-ended venturi throats, each with an annular converging inlet. The bowl has contoured interior air-flow director surfaces and a perimeter rim for supporting an air filter. The contoured surfaces extend between the rim and each throat, defining concave air-guide surfaces, each converging on one throat, surrounding it, and coextensive with its converging inlet — so air follows the concave guide surfaces into the throats "substantially without an abrupt change of direction." Directed to the airflow/anti-turbulence geometry.

Representative dependent claims worth noting:

• Claim 8 — the "alignment means" of claim 6 is specifically a positioning cord formed in the lower outer cylindrical surface, sized to abut the positioning cord of an adjacent sleeve.
• Claim 11 — adds a booster venturi whose support conduit passes through a side opening in the sleeve, with a ring nozzle suspended in the passage and fuel conduit means.
• Claim 12 / Claim 14 — the booster's venturi constriction and the sleeve's wall constriction are axially offset to form overlapping zones of reduced air pressure.
• Claim 16 — adds the side opening in the sleeve for receiving the booster's support conduit.
• Claim 18 — the body defines parallel bores, and the venturi sleeves inserted into them form the throats.

Prosecution / prior art context

• Prior art cited by examiner (8–9 references): DE 1008052 B; US 4,235,828 (Howes); US 4,250,856 (Abbey); US 4,387,685 / 4,387,685 B1 (Abbey, variable venturi); US 4,808,007 (Komax); JP S63-9665 (Nippon Carbureter); US 4,966,735 (Lorusso, non-leaking venturi carburetor); US 5,667,730 (Barfield, float bowl attachment).
• Non-patent citations: HP Books, Weber Carburetors (Pat Braden, 1988); Performance Racing Industry Magazine, p. 28 (undated).
• Later citations/continuations: The '470 patent is a common parent of US 5,807,512 ('512, replaceable booster venturis — CIP) and US 6,120,007 ('007, color-coded interchangeable components — CIP), both naming Barry Grant.

CAFC 2026 docket search — result

I did not find any Federal Circuit 2026 appeal, oral argument, or decision docketed under US 5,863,470. My searches returned only unrelated 2026 CAFC opinions/orders (e.g., AudienceScience v. Google, FedEx v. Qualcomm, Apple v. SpaceTime3D, VDPP v. Volkswagen), none of which concern the '470 patent.

One 2026 district-court matter did appear and may be worth independent verification: Holley Performance Products Inc. v. Aces Fuel Injection, Inc., No. 1:26-cv-00059 (E.D. Tenn., filed March 6, 2026) (per RPX Insight). Holley is the current recorded assignee of the '470 patent, but the search snippet did not disclose which patents are asserted in that case. I cannot confirm the '470 patent is at issue, and I am flagging this as an open item rather than a finding.

Uncertainty / caveats

• The patent is expired (anticipated expiration Feb. 14, 2017), so it cannot be asserted for ongoing infringement today.
• The phrase "positioning cord" appears literally throughout the specification and claims (also described as a "flattened cord"). I have not altered it to "chord," consistent with the instruction to interpret identifiers literally; note that the term is unusual and may be an artifact of the original drafting.
• Assignee history is long and finance-driven (Branch Banking & Trust → High Performance Industries → Demon Fuel Systems → Holley Performance Products, with numerous security interests/releases through Wells Fargo, Wilmington Trust, LBC, Hawthorn, GE Capital, Cerberus, UBS, AEA, and 2021 releases). I relied on the Google Patents assignment record for these; individual reel/frame accuracy was not independently verified.
• I have no authoritative information confirming any current litigation or CAFC appeal involving this specific patent number.

I'll research litigation involving US patent 5863470. Let me run several targeted searches.

The initial searches returned mostly unrelated noise (a different "‘347 patent" owned by Cascades/Sony, a Japanese JP5863470, and an OSTI ID). Let me target litigation databases and carburetor-industry disputes directly.

The forum chatter is unreliable and conflates several different patents (e.g., the 2004 Holley v. Barry Grant case concerned U.S. 6,286,817, a fuel-bowl level indicator). Let me check authoritative litigation databases for the specific number.

Bottom line

I was unable to identify any litigation asserting or otherwise involving U.S. Patent No. 5,863,470. To the extent I found any related activity, it does not involve the '470 patent. I want to be explicit about the limits of this answer: I was not able to complete a docket-level search of PACER, CourtListener, or the Unified Patents litigation portal for this specific number before my search budget was exhausted, so this is "not found," not a certified negative.

What I searched and what came back

Targeted searches on the patent number returned almost entirely false positives, which I flag because they are easy to mistake for '470 litigation:

The one carburetor-industry case I found — and why it does not count

There was real litigation between the '470 patent's inventor and its eventual assignee:

• Holley Performance Products, Inc. v. Barry Grant, Inc., U.S. District Court for the Northern District of Illinois (2004) — Holley filed for a declaratory judgment of non-infringement and invalidity; Grant's motion to dismiss was granted (Judge Conlon) for lack of a justiciable controversy.
• Barry Grant, Inc. v. Holley Performance Products, Inc., filed October 19, 2004, U.S. District Court for the Northern District of Georgia (Grant's affirmative infringement suit).

Critically, the patent at issue in that dispute was U.S. Patent No. 6,286,817 — an automotive carburetor fuel bowl with a fuel level indicator — not 5,863,470. I am therefore not reporting it as litigation involving the '470 patent. Note also that Barry Grant is the named inventor of the '470 patent; so the same parties are connected, which is exactly the kind of overlap that generates erroneous secondary-source claims.

I saw substantial online forum discussion (vintage-mustang.com, hotrodders.com, camaros.net, competitionplus.com) describing "Holley sued Barry Grant for copying the carburetor design," but that material is unsourced hobbyist commentary, conflates multiple patents and products (the "Claw" line, the Demon line), and I could not corroborate any of it against a docket. I would not rely on it.

Context that bears on the (non-)result

Per the patent record itself, US 5,863,470:

• Was filed 1997-02-14, priority 1996-02-13, granted 1999-01-26, inventor Barry Grant, original assignee Individual.
• Is "Expired – Lifetime" with an anticipated expiration of 2017-02-14. Enforcement incentives were near zero after that date.
• Has a family that includes US 5,807,512 (replaceable booster venturis), US 6,120,007 (color-coded interchangeable components), US 5,809,972, and US 7,255,331.
• Shows a long chain of security-interest and assignment records (Branch Banking & Trust → High Performance Industries → Demon Fuel Systems → Holley Performance Products), plus later lender security interests (Wells Fargo, Wilmington Trust, LBC, Hawthorn, GE Capital, Cerberus, UBS, AEA). These are collateral/ownership filings, not litigation. If you are reviewing a corporate IP schedule, do not let these reassignments be misread as lawsuit activity.

What I recommend to confirm a true negative

To convert this from "not found" into an authoritative answer, the following should be run directly (I could not complete these):

1. PACER Case Locator — search "5,863,470" and "5:863,470" across all district courts; also search party "Barry Grant, Inc." and "Demon Fuel Systems, Inc." with Nature of Suit 830.
2. CourtListener / RECAP free docket search for the patent number.
3. Unified Patents Litigation Portal (portal.unifiedpatents.com/litigation) — patent-level case list for US-5863470.
4. Lex Machina / Docket Navigator — patent-number search; these also capture ITC Section 337 actions.
5. USPTO Patent Assignment and Patent Trial & Appeal Board records — no IPR/PGR appears for '470 (it predates the AIA, and I found none), but confirm via PTAB API.

Caveat

I could not verify the litigation history of this patent to a level I would be comfortable certifying in a legal proceeding. My answer is: no litigation involving US 5,863,470 was identified in the sources I could reach; the closest related dispute (Holley v. Barry Grant, 2004) concerned U.S. 6,286,817 and is not '470 litigation. Please treat this as preliminary pending a PACER/Unified Patents docket pull.

I'll verify the canonical list against web sources before writing anything up.

Let me run a few more targeted checks before concluding.

One final check on litigation/appeal history and the expiration timeline.

Proceedings overview

Total AIA trial proceedings on file for US 5,863,470: 0. There are no IPRs, no PGRs, and no CBM reviews — active, terminated, settled, or otherwise. The patent has never been tested at the PTAB, so there is no claims-invalidated / claims-sustained breakdown to report: all 19 claims stand as issued, though they now face the more fundamental problem that the patent expired on 2017-02-14. For a defendant today, the defensive posture is unusual: you are not facing a hardened patent, and you are not facing a cancelled one — you are facing an expired, never-adjudicated patent, which means the venue with the most leverage (PTAB) is effectively closed to you and your defense runs through § 102/§ 103 in district court, § 112, laches/§ 286 damages limits, or straight non-infringement.

No proceeding to report

The "PTAB proceedings on file" block is the canonical USPTO Open Data Portal list and it returns zero AIA trial proceedings for US 5,863,470. I ran independent web checks (Google Patents, Justia, FreePatentsOnline, Unified Patents' patent portal, and general PTAB/IPR searches) and found no IPR, PGR, or CBM docket naming this patent as the challenged patent. I found no Final Written Decision, no institution decision, no termination, and no Federal Circuit appeal arising from a PTAB proceeding on the '470 patent. I am not going to manufacture a proceeding number to fill this section — there is nothing to fill.

Two structural reasons reinforce the "no activity" finding, and they are worth flagging because they are the why:

• The patent expired before the AIA trial regime could realistically be brought to bear on it. The application was filed 1997-02-14 and the patent issued 1999-01-26, giving a 20-year term ending 2017-02-14 — which the Google Patents record itself confirms with a "2017-02-14 — Anticipated expiration" legal event and a status of "Expired - Lifetime." IPRs on expired patents are possible only in narrow circumstances (typically to clear past damages in a live litigation), and none appears on file.
• The patent's statutory window for the other AIA vehicles is closed. With an effective priority date of 1996-02-13 (provisional Ser. No. 60/011,550), the '470 patent is not eligible for post-grant review (limited to claims with effective filing dates on or after 2013-03-16) and is not a covered business method patent. IPR under § 311 was the only available AIA tool — and nobody used it.

Strategic summary

The claim landscape for the '470 patent is therefore trivially simple: no claims are cancelled, and no claims are PTAB-sustained. Claims 1–19 stand as issued and were never challenged. That is not the same as "the patent has survived two IPRs and is hardened" — an untested claim is an unknown quantity, not a strong one. The claims break into four independent families: claim 1 (four-bore body with stepped bores, shoulders, replaceable venturi sleeves, and coextensive concave bowl flow directors), claim 6 (same sleeve/shoulder architecture plus an "alignment means" — the positioning cord of claim 8), claim 15 (the venturi sleeve itself, as an article of manufacture, with upper/lower cylindrical surfaces, shoulder, and positioning cord), and claims 3/13/17 (the bowl-side flow-director inventions, which do not require a replaceable sleeve at all except in claim 18). Because no IPR was ever filed, there is also no estoppel on the table — § 315(e)(2) estoppel attaches only to petitioners who filed and were instituted on, and there are none. Every prior-art ground, including art that was before the examiner (DE 1008052B, US 4,235,828, US 4,250,856, US 4,387,685, JPS639665, US 4,808,007, US 4,966,735, US 5,667,730) and art that was not, remains fully available to a district-court defendant or an IPR petitioner.

The pattern signals point away from a serial PTAB challenger. The '470 patent is one of three Barry Grant carburetor patents from the same 1996–1998 family — the sibling filings US 5,807,512 ("Carburetor with replaceable booster venturis") and US 6,120,007 ("Carburetor with color-coded interchangeable components") are both continuation-in-parts of this application, and US 6,120,007 is itself cited against the '470 patent record. Ownership has passed through a long chain (Barry S. Grant → High Performance Industries, Inc. → Demon Fuel Systems, Inc. → merged into Holley Performance Products, Inc. in 2014), leaving Holley as the current assignee of record via a series of security-interest filings. There is no defensive aggregator (Unified Patents or similar) anywhere in the chain, and no evidence of aggressive Patent Owner PTAB appeals — consistent with the absence of any proceeding to appeal. Note that the well-known Holley/Demon dispute of the early 2000s that bubbled up in enthusiast forums was a design/trade-dress fight, not a PTAB campaign, and predates the AIA anyway; I flag it only to head off any inference that it generated IPR paper. It did not.

Recommended next steps

• If you are a defendant being asserted against today: the single most important fact is that this patent expired 2017-02-14. For any alleged infringement after that date there is no case — an expired patent cannot be infringed. Your damages exposure is capped at the six-year lookback under 35 U.S.C. § 286 (i.e., to conduct before 2020-09-27 only if suit was filed on or around today's date), and if you can show the patent owner knew of your product and sat on it, laches-type and equitable defenses may further compress the window. Demand a claim-by-claim, date-by-date damages chart and check the last date of the accused conduct against the expiration date.
• Do not expect a PTAB shortcut. With the patent expired, an IPR would be an expensive way to attack claims that are already legally unenforceable going forward. The realistic defenses are non-infringement (particularly around the "concave flow director surfaces... substantially coextensive with the annular converging inlet surfaces" limitations of claims 1–5, 13, and 17, and the shoulder/alignment architecture of claims 6–12) and invalidity in the district court, where there is no BRI squeeze and where you can raise § 112 written-description/enablement (a real vulnerability for the coined "coextensive" language, which appears in no cited reference).
• Build the invalidity case from scratch. There is no FWD to lean on and no estoppel to worry about. Start from the nine references of record plus Non-Patent Citations ("HP Books, Weber Carburetors, Pat Braden, 1988"; "Performance Racing Industry Magazine, p. 28, Twisted Wedge Aluminum Cylinder Heads"). The Weber literature is the most promising starting point, because multiple-venturi carburetors with removable/replaceable venturi inserts and bowl-to-throat transition shaping were well known in the pre-1996 racing-carburetor art.
• If you are the patent owner (Holley) or its counsel: the absence of any IPR is itself the signal you should internalize. Well-asserted patents in a crowded aftermarket — and this one sits squarely in the high-performance carburetor aftermarket — eventually attract IPRs from competitors and defensive aggregators. That none was ever filed against a patent family with this commercial footprint most likely reflects the expiration date (nobody files an IPR against a patent with no forward life), not the strength of the claims. Do not represent claims 1–19 to a counterparty as "survived IPR" or "PTAB-validated." They were never tested, and representing otherwise would be materially misleading.
• Verify against the primary sources before relying on this. Confirm the zero-proceeding finding at USPTO Patent Center for application 08/801,721 and PTAB E2E, and confirm the expiration and assignment chain on the Google Patents record for US 5,863,470. The AIA-trial ODP block supplied in this prompt is consistent with what I found, but it is an ingest snapshot — if a proceeding was filed in the last few weeks it may not yet be indexed, and I found no web evidence of any.

I'll verify the assignment record and ownership history against live sources before reconstructing the chain.

Now let me dig into the correspondent-of-record data and the bankruptcy/acquisition details.

US 5,863,470 — Assignment Record Reconstruction

Method note (read first): I could not query assignmentcenter.uspto.gov or assignment.uspto.gov directly — I have no browser session for those portals, only general web search. The reel/frame data below is transcribed from the USPTO legal-events record as mirrored on Google Patents (the authoritative full text supplied for this analysis), which reproduces reel/frame, conveyance type, assignor, assignee, and effective date. It does not reproduce the correspondent-of-record (recording attorney/firm) field. I therefore cannot report correspondents, and I will not invent them. That omission is itself material to signal #3 below, which I have marked insufficient data rather than guessed.

Also resolving an item the prior section left open: the 2026 suit Holley Performance Products Inc. v. Aces Fuel Injection, Inc., 1:26-cv-00059 (E.D. Tenn., filed 03/06/2026), asserts Holley's EFI throttle-body patents — the complaint analysis (Ex Parte / PACER-derived) charts independent claim 9 of a '515 patent and independent claim 1 of a '083 patent, both of which claim "a throttle body having an upper inlet and a lower outlet." Neither is US 5,863,470. The docket also carries a copyright count (17 U.S.C. § 501) alongside the patent count (NOS 830). The '470 is not in that case. No contradiction with the prior section, but it closes the loop.

Inventors

Unusual pattern — inventor retained personal title. The patent as issued lists the original assignee as "Individual," not a corporation. There is no recorded pre-issuance assignment from Grant to Barry Grant Inc. on this patent. The first recorded instrument touching the '470 is a security agreement Grant gave personally to Branch Banking and Trust Company (reel 022162/0214, executed 2008-12-23, recorded 2009-01-28). So a patent covering the flagship product of Grant's own operating company sat on Grant's personal balance sheet for roughly a decade.

That is not the "inventors departed within 12 months" pattern, but it is the related warning sign: personal-owner IP over a leveraged operating business is a classic precondition for a distress transfer, and that is exactly what happened (see timeline and signal #6).

Original assignee

• Entity on the issued patent: Barry S. Grant, individually (Google Patents renders the original assignee field as "Individual"). No corporate assignee appears on the face of the patent.
• Commercializing entity: Barry Grant Inc. (d/b/a Demon Carburetion), Dahlonega, Georgia — five product lines: Demon Carburetors, BG Fuel Systems, Triple-D Induction, Nitrous Works, Rush Performance Filters. Yes, an operating product line embodied these claims: the four-barrel Demon carburetor bodies with replaceable venturi sleeves and contoured bowl flow-director surfaces. Multiple independent contemporaneous sources (Dragzine, FordMuscle, BangShift, Engine Builder) confirm the Demon brand shipped from Dahlonega in the late 1990s and 2000s. I could not pin the specific SKU/part number to a claim chart.
• Primary line of business: aftermarket high-performance carburetion and fuel systems for racing/street performance.
• Current status:
  • Barry Grant Inc. — filed Chapter 11 in October 2009; announced cessation of operations and conversion to Chapter 7 liquidation on February 18, 2011 after 26 years. In Grant's own words: "Reluctantly now we must convert to chapter 7 liquidation after 26 years of business… We have even lost our home." Dissolved/liquidated.
  • Barry S. Grant, individual — no longer an owner of record after 2011-07-06.
  • Current owner of record: Holley Performance Products Inc., now Holley Inc. (NYSE: HLLY), Bowling Green, Kentucky — a public operating company, ~1,400 employees, ~$600M+ revenue scale, with the Demon brand still in its portfolio (explicitly listed as a Holley-owned brand by reseller EFISystemPro). Operating.

Assignment timeline

Chronological. Reel/frame and dates are as recorded; "executed" dates are the record's Effective date field.

1. 2008-12-23 (executed) / recorded 2009-01-28 — Reel 022162/0214

   • Conveyance: Security Agreement
   • Assignor: Grant, Barry S. (individually)
   • Assignee: Branch Banking and Trust Company (Georgia)
   • Correspondent: not retrievable from available sources.
   • Context: Securitization — Grant pledges his personal IP, ~10 months before his operating company files Chapter 11.

2. 2011-07-06 (executed) / recorded 2011-07-08 — Reel 026565/0001

   • Conveyance: Assignment of Assignors' Interest
   • Assignor: Grant, Barry S.
   • Assignee: High Performance Industries, Inc. (Kentucky)
   • Correspondent: not retrievable.
   • Context: Distress transfer. Executed ~4.5 months after Barry Grant Inc.'s Feb 18, 2011 Chapter 7 conversion, and ~1.5 months before the July 2011 press release announcing the Demon/BG brand revival "run by a fresh team." The buyer is the entity that resurrected the brands.

3. 2011-12-13 (executed) / recorded 2011-12-13 — Reel 027371/0471

   • Conveyance: Assignment of Assignors' Interest
   • Assignor: High Performance Industries, Inc.
   • Assignee: Demon Fuel Systems, Inc. (Kentucky)
   • Correspondent: not retrievable.
   • Context: Internal reorganization — IP moved from the holding entity into the revived brand-name operating entity within ~5 months.

4. 2011-12-28 (executed) / recorded 2012-01-04 — Reel 027480/0708

   • Conveyance: Security Agreement
   • Assignor: Demon Fuel Systems, Inc.
   • Assignee: Wells Fargo Capital Finance, Inc. (California)
   • Correspondent: not retrievable.
   • Context: Securitization — working-capital financing of the revived brand.

5. 2011-12-28 (executed) / recorded 2012-01-06 — Reel 027490/0852

   • Conveyance: Security Agreement
   • Assignor: Demon Fuel Systems, Inc.
   • Assignee: Wilmington Trust, National Association (Minnesota)
   • Correspondent: not retrievable.
   • Context: Securitization — second lien layered within 48 hours of Wells Fargo.

6. 2012-06-07 (executed) / recorded 2012-06-08 — Reel 028342/0295

   • Conveyance: Security Agreement
   • Assignor: Demon Fuel Systems, Inc.
   • Assignee: LBC Credit Partners II, L.P., as agent (Pennsylvania)
   • Correspondent: not retrievable.
   • Context: Securitization — refinancing; sixth month of the revived entity's life.

7. 2012-06-08 (executed) / recorded 2012-06-16 — Reel 028388/0916

   • Conveyance: Termination and Release of Security Interest
   • Releasing party (record's ASSIGNOR field): Wilmington Trust, N.A., as successor-by-merger to Wilmington Trust FSB
   • Owners of record benefiting: Demon Fuel Systems, Inc.; Holley Performance Products, Inc.; Sniper Motorsports, Inc.
   • Correspondent: not retrievable.
   • Context: Securitization housekeeping. Note the tell: the same Wilmington Trust lien encumbered Holley and Sniper Motorsports IP alongside Demon — i.e., the three names were already a cross-collateralized family two years before the 2014 merger.

8. 2012-06-07 (executed) / recorded 2012-06-29 — Reel 028487/0941

   • Conveyance: Security Agreement
   • Assignor: Demon Fuel Systems, Inc.
   • Assignee: Hawthorn Finco, LLC (New York)
   • Correspondent: not retrievable.
   • Context: Securitization — third concurrent lender in the June 2012 package.

9. 2013-10-24 (executed) / recorded 2013-10-25 — Reel 031496/0062

   • Conveyance: Security Agreement
   • Assignors: Holley Performance Products Inc.; Demon Fuel Systems, Inc.; QFT Holdings, Inc.; and others
   • Assignee: General Electric Capital Corporation, as agent (Colorado)
   • Correspondent: not retrievable.
   • Context: Securitization / consolidation — an integrated credit facility across the Holley family of brands.

10. 2013-10-24 (executed) / recorded 2013-10-30 — Reels 031513/0841 (LBC), 031512/0872 (Hawthorn), 031508/0928 (Wells Fargo Bank, N.A., as agent)

    • Conveyance: Release by Secured Party ×3
    • Owners of record benefiting: Demon Fuel Systems, Inc.
    • Correspondent: not retrievable.
    • Context: Securitization housekeeping — the three 2011–2012 liens cleared as the GE facility came on.

11. 2014-04-10 (executed) / recorded 2014-05-06 — Reel 032826/0413

    • Conveyance: Merger
    • Assignor: Demon Fuel Systems, Inc.
    • Assignee: Holley Performance Products Inc. (Kentucky)
    • Correspondent: not retrievable.
    • Context: Acquisition by merger — Holley absorbs the Demon entity outright. This is the last true change of ownership in the chain.

12. 2015-09-22 (executed and recorded) — Reel 036664/0148

    • Conveyance: Patent Security Agreement
    • Assignors: Holley Performance Products Inc.; QFT Holdings, Inc.; Holley Performance Systems, Inc.; and others
    • Assignee: Cerberus Business Finance, LLC, as Collateral Agent
    • Correspondent: not retrievable.
    • Context: Securitization — LBO-style debt, consistent with Holley's pre-SPAC capital structure.

13. 2015-09-22 (executed) / recorded 2015-09-24 — Reel 036686/0964

    • Conveyance: Release of Security Interest in Patent Collateral
    • Releasing party: General Electric Capital Corporation
    • Owners benefiting: Holley Performance Products Inc.; Holley Performance Systems, Inc.; Demon Fuel Systems, Inc.; QFT Holdings, Inc.
    • Correspondent: not retrievable.
    • Context: Securitization housekeeping — GE facility retired as Cerberus facility funded.

14. 2018-10-26 (executed) / recorded 2018-11-05 — Reel 047419/0953

    • Conveyance: Release by Secured Party
    • Releasing party: Cerberus Business Finance, LLC
    • Owners benefiting: Holley Performance Products Inc.; Powerteq LLC; MSD LLC; QFT Holdings, Inc.; Holley Performance Systems, Inc.; Accel Performance Group LLC
    • Correspondent: not retrievable.
    • Context: Securitization housekeeping — Cerberus facility retired at the 2018 UBS refinancing.

15. 2018-10-26 (executed) / recorded 2018-11-06 — Reel 047429/0343

    • Conveyance: Security Interest
    • Assignors: Flowmaster, Inc.; APR, LLC; Accel Performance Group LLC; and others (incl. Holley Performance Products Inc.)
    • Assignee: UBS AG, Stamford Branch, as Collateral Agent (Connecticut)
    • Correspondent: not retrievable.
    • Context: Securitization — first-lien refinancing across the entire Holley platform.

16. 2018-10-26 (executed) / recorded 2018-11-18 — Reel 048475/0125

    • Conveyance: Corrective Assignment (deletes patent numbers previously recorded at reel 047429/frame 0343; assignor confirms the security interest)
    • Assignee: UBS AG, Stamford Branch
    • Correspondent: not retrievable.
    • Context: Correction only — a scrivener's fix to the UBS collateral schedule, not a change of ownership.

17. 2018-10-26 (executed) / recorded 2018-11-18 — Reel 048147/0510

    • Conveyance: Security Interest
    • Assignors: Flowmaster, Inc.; APR, LLC; Accel Performance Group LLC; and others (incl. High Performance Industries, Inc.)
    • Assignee: AEA Debt Management LP, Second Lien Collateral Agent (Connecticut)
    • Correspondent: not retrievable.
    • Context: Securitization — second lien stacked on the same closing date.

18. 2021-11-18 (executed) / recorded 2021-11-24 — Reel 058944/0279

    • Conveyance: Release by Secured Party
    • Releasing party: AEA Debt Management LP, as Second Lien Collateral Agent
    • Owners benefiting: High Performance Industries, Inc.; Holley Performance Systems, Inc.; Holley Performance Products Inc.; Racepak LLC; Powerteq LLC; MSD LLC; Accel Performance Group LLC; APR, LLC; Flowmaster, Inc.
    • Correspondent: not retrievable.
    • Context: Securitization housekeeping — second lien cleared.

19. 2021-11-18 (executed) / recorded 2021-11-24 — Reel 058948/0926

    • Conveyance: Release by Secured Party
    • Releasing party: UBS AG, Stamford Branch, as First Lien Collateral Agent
    • Owners benefiting: same nine-entity list as above
    • Correspondent: not retrievable.
    • Context: Securitization housekeeping — first lien cleared at the post-SPAC recapitalization. Holley Inc. has remained the last owner of record since 2014-04-10.

Directional note on reels 028388/0916, 031508–031513, 036686/0964, 047419/0953, 058944/0279, 058948/0926: these are release records. The record's "owner name" is the debtor/patent owner and the ASSIGNOR field names the secured party releasing, which is the reverse of an ordinary assignment entry. I have read them that way.

Timeline diagram

timeline
    title Ownership of US 5863470
    1996 : Filed by Barry Grant as individual
    1999 : Patent issued Jan 26
    2008 : Security interest to Branch Banking and Trust
    2009 : Barry Grant Inc files Chapter 11
    2011 : Barry Grant Inc converts to Chapter 7
         : Assigned to High Performance Industries
         : Reassigned to Demon Fuel Systems
    2012 : Three security agreements on the revived brand
         : Wilmington Trust lien released
    2013 : Loans consolidated under GE Capital
    2014 : Demon merges into Holley Performance Products
    2015 : Cerberus takes security interest
    2017 : Patent term expires Feb 14
    2018 : UBS and AEA take security interests
    2021 : All security interests released
    2026 : Holley sues Aces on other patents

NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT. Every post-2008 holder of record is an operating entity or a lender. High Performance Industries, Inc. (reel 026565/0001) and Demon Fuel Systems, Inc. (reel 027371/0471) were the vehicles used to relaunch the Demon Carburetion and BG Fuel Systems product lines — contemporaneous trade press (Engine Builder, BangShift, Moore Good Ink, July 2011) reports a physical relaunch at SEMA 2011 with product shipping, and Demon-brand carburetors remain in Holley's catalog today. No assignee carries an "IP / Patents / Licensing / Ventures" suffix. The one name that reads generic ("High Performance Industries") is rebutted by the product evidence, so under the stated rule I do not treat naming as a finding. Holley is a public registrant (NYSE: HLLY).

2. Known asserter in the chain — NOT PRESENT. I checked the entire chain against the supplied list (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities): no match on any assignee in any of the 19 entries. The current and sole owner since 2014-04-10 is Holley Performance Products Inc., a competitor-manufacturer.

3. Repeat correspondent across the chain — INSUFFICIENT DATA. This is the one signal I cannot evaluate. The correspondent-of-record field is not exposed in the Google Patents legal-events mirror I had to rely on, and I have no Assignment Center session. Recording counsel for reels 022162/0214, 026565/0001, 027371/0471 and the 2011–2013 security packages would be the single highest-value next check — particularly whether the pre- and post-bankruptcy conveyances (2011-07-06 and 2011-12-13) share counsel, which would confirm whether the brand revival was a coordinated single-plan restructuring rather than an arm's-length purchase. Recommend direct pull from assignmentcenter.uspto.gov before drawing any conclusion here.

4. Cascading transfers — PRESENT (narrow, and explained). Two consecutive assignments within ~5 months: Grant → High Performance Industries (executed 2011-07-06, reel 026565/0001) → Demon Fuel Systems (executed 2011-12-13, reel 027371/0471). The literal <24-month criterion is met, but the pattern is corporate reorganization, not obfuscation: both assignees are Kentucky entities, the second is the brand-name operating company publicly announced in July 2011, and the chain terminates in a real product business rather than a licensing shell. No shared registered-agent address evidence, no single-purpose LLCs, no common-principal flag available from the data I hold. I mark it present-but-benign.

5. Pre-litigation transfer — NOT PRESENT / NOT APPLICABLE. The only litigation touching this owner is 1:26-cv-00059 (filed 2026-03-06), and it asserts Holley's EFI throttle-body patents (the '515 and '083 per the complaint analysis), not the '470. Separately, the '470 expired at end of statutory term on 2017-02-14 (fee years 4/8/12 paid 2002-06-19, 2006-06-08, 2011-01-18), so it is unassertable today regardless of ownership. No transfer sits within 6 months of any suit naming this patent.

6. Bankruptcy fire-sale — UNCLEAR (distress context confirmed; estate route not confirmed). On the business facts the signal is live and well-documented: Barry Grant Inc. filed Chapter 11 in October 2009 and converted to Chapter 7 liquidation on February 18, 2011 (Dragzine, FordMuscle, Grassroots Motorsports, LX Forums, all quoting Grant's statement). The '470 moved to a new owner on 2011-07-06, ~4.5 months later. On the record facts, however, the assignor was Grant personally (reel 026565/0001, ASSIGNOR: GRANT, BARRY S.), and the patent never appears to have been held by Barry Grant Inc. — the original assignee field reads "Individual." So I cannot confirm the patent passed through the bankruptcy estate or was sold in the proceedings; it may have been conveyed outside the estate. I mark this unclear rather than assert a fire-sale I cannot document. The related personal security interest to Branch Banking and Trust (reel 022162/0214, executed 2008-12-23) is documented and predates the Chapter 11 filing by ~10 months.

7. Privateering — NOT PRESENT. No operating-company-to-NPE transfer exists in this chain. The 2014 transaction was an outright merger of Demon Fuel Systems into Holley (reel 032826/0413) — a product-line acquisition by a competitor, with Holley continuing to make and sell Demon-branded product. No NPE asserts on Holley's behalf, and Holley is the plaintiff itself in the 2026 action.

8. Defensive aggregator — NOT PRESENT. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at a litigating operating company.

Verdict

Operating-company assertion.

The chain terminates at Holley Performance Products Inc. via a documented merger effective 2014-04-10, recorded 2014-05-06 at reel 032826/0413 — a public registrant (NYSE: HLLY) that manufactures and sells carburetion and EFI products under the Demon brand this patent helped launch, and that is presently suing a competitor in Holley Performance Products Inc. v. Aces Fuel Injection, Inc., 1:26-cv-00059 (E.D. Tenn.). Zero NPE signals are affirmatively present: no shell assignee, no listed asserter, no privateering, no defensive-aggregator termination, and no pre-litigation transfer. The one genuinely notable feature of this record is the opposite of a troll footprint — 19 recorded instruments over 13 years, dominated by first- and second-lien pledges and releases from six separate lenders (Branch Banking and Trust 022162/0214; Wells Fargo 027480/0708; Wilmington Trust 027490/0852 and release 028388/0916; LBC 028342/0295; Hawthorn 028487/0941; GE Capital 031496/0062; Cerberus 036664/0148; UBS 047429/0343 and 048475/0125; AEA 048147/0510; 2021 releases 058944/0279 and 058948/0926). NPEs do not typically pledge their patents as collateral for syndicated operating credit. The only residual caveat is the 2011 distress transfer out of the collapsed Barry Grant business (signal #6, marked unclear) and the unverified correspondent field (signal #3, insufficient data) — both worth a direct Assignment Center pull, neither sufficient to change the verdict.

Verification links:

• USPTO Assignment Center — https://assignmentcenter.uspto.gov/
• USPTO Patent Assignment Search (legacy) — https://assignment.uspto.gov/patent/index.html#/patent/search?q=[5863470](/patent/5863470)
• Google Patents legal events for the '470 (source of the reel/frame data above) — https://patents.google.com/patent/US5863470/en
• RPX Insight docket for 1:26-cv-00059 — https://litigation.rpxcorp.com/litigation/tnedce-[123355](/patent/123355)-holley-performance-products-v-aces-fuel-injection

Open items I could not close

1. Correspondent of record for every reel above — not retrievable with the tools available; requires direct Assignment Center access.
2. Whether the '470 passed through the Barry Grant Inc. Chapter 7 estate or was conveyed personally outside it — the record shows Grant individually as assignor, but the underlying bankruptcy schedules/sale motion were not located.
3. Exact Demon part numbers practicing the claims, for a product-to-claim mapping.

I'll research the cited prior-art references against US 5,863,470. Let me run several searches in parallel.

Scope, sources, and two caveats before the analysis

Patent confirmed. The reference in this task is US 5,863,470 A, "Carburetor with a replaceable venturi sleeves," App. 08/801,721, invented by Barry Grant, filed Feb. 14, 1997, issued Jan. 26, 1999, claiming benefit of provisional 60/011,550 (Feb. 13, 1996). The full text above corroborates the earlier-generated summary; I found no contradiction with that prior section, and I am building on it rather than repeating it.

Caveat 1 — date discrepancy. The task header states "Current Date: April 26, 2026," while the document metadata says "Today's date: 2026-09-27." I cannot reconcile these; I flag it rather than pick one. It does not change the substantive prior-art analysis, because this patent expired (anticipated expiration Feb. 14, 2017).

Caveat 2 — search coverage. The prior-art list below is taken from the "Patent Citations" / "Citations" tables in the authoritative full text (9 patent citations + 3 non-patent citations). I was able to retrieve the substance of US 4,235,828, US 4,250,856, US 4,387,685, US 4,966,735, and US 5,667,730 through live search. I could not retrieve readable text/figures for DE 1008052 B, JP S63-9665, or US 4,808,007 before my search budget was exhausted. For those three I mark their content as unverified and do not invent details.

Also note one cross-reference worth keeping straight: the full text lists both "Citations (8)" and "Patent Citations (9)." The ninth entry is US 4,387,685 B1, the reexamination certificate for the Abbey '685 patent — not a separate invention. The earlier-generated section correctly flagged the B1.

Legal frame (pre-AIA § 102)

App. 08/801,721 was filed Feb. 14, 1997 — pre-AIA applies (the first-inventor-to-file provisions govern applications filed on or after Mar. 16, 2013). With a provisional priority date of Feb. 13, 1996:

• § 102(b) statutory bar — printed publications/patents more than one year before the U.S. filing date (critical date ≈ Feb. 13, 1995, using the provisional date). Every cited reference except US 5,667,730 predates this and is available as § 102(b) art as to the subject matter it discloses.
• § 102(a) — art before the invention date (also covers the same references).
• § 102(e) — U.S. patents granted on applications filed before the applicant's date. US 5,667,730 (filed Sept. 13, 1995) qualifies only here; it is not a § 102(b) reference.

A key structural point for everything below: to anticipate any of the '470 claims, a single reference must disclose every limitation. The '470 claims are built from two independent inventive clusters, and no single cited reference appears to supply both:

1. Sleeve cluster — removable venturi sleeve with a stepped two-diameter outer surface (upper 42 / lower 44) joined by an external annular shoulder 46 seating on bore shoulder 36, plus a "positioning cord" 50 in the lower cylindrical surface facing an adjacent sleeve, plus side slot 52 (claims 1, 6, 8, 15, 16).
2. Bowl cluster — manifold bowl concave flow-director surfaces (104–110) surrounding each bore, coextensive with the sleeves' converging inlet 62, separated by ridges (105–111) (claims 1, 2, 3, 4, 5, 13, 17, 18, 19).

The nine patent citations

1. US 4,966,735 — Lorusso, "Non-leaking venturi carburetor"

• Full citation: M. Lorusso, US 4,966,735 A. Filed 1989-04-12; issued 1990-10-30.
• Status: § 102(b) art.
• Description (verified): A carburetor body with cylindrical bores into which "precisely and removably fitted liners" are installed; the liners' inner surfaces are contoured as a venturi (inlet → throat → diverging outlet). Fuel is discharged peripherally through ports near the throat; no booster venturi is used. The specification expressly states the carburetor "is readily modified by removing the liners and installing a new set of liners which may have different dimensions for the venturi and a different port pattern." It even discusses "losses due to turbulences as the air enters the venturis."
• Potential § 102 impact — this is the single closest reference to the sleeve concept:
  • Claim 15 (sleeve as article): Discloses a removable venturi liner with an internal venturi passage and constriction. Fails to disclose the larger-diameter lower outer cylindrical surface, the external annular shoulder joining the two outer surfaces, and the positioning cord. No full anticipation.
  • Claim 1 / Claim 6: Discloses removable venturi sleeve in a bore (the independent-claim preamble), but does not disclose the two-diameter stepped bore with internal shoulder, the sleeve's mating stepped outer surfaces/shoulder, or alignment means. No anticipation.
  • Claim 3: Lorusso's focus is the liner/fuel-port geometry, not bowl concave flow-director surfaces coextensive with the converging inlet. No anticipation.
  • Net: Best characterized as the primary § 103 starting reference for the "replaceable venturi liner" idea, and strong § 102 art only for a hypothetical broad claim to "a carburetor body with a removable venturi-contoured liner." It does not anticipate any issued independent claim.

2. US 4,235,828 — Howes, "Fuel economizer employing improved turbulent mixing of fuel and air"

• Full citation: L. D. Howes, US 4,235,828 A. Filed 1979-06-20; issued 1980-11-25. (Class F02M 23.)
• Status: § 102(b) art.
• Description (verified): A carburetor (illustrated on a VW Solex 28 PICT-1) fitted with a "sleeve 24 for inserting in the venturi 23" — i.e., a venturi-shaped insert with a neck-down section 25. "Through the slotted sides of which projects the fuel pipe 21," the jet opening terminating axially in the center of the sleeve's venturi. The sleeve reduces the venturi area to increase velocity/turbulence.
• Potential § 102 impact:
  • Claim 15/16: Discloses a removable venturi insert/sleeve (claim 15 preamble) and a side opening through which a fuel-delivery conduit projects (claim 16's "side opening for receiving a support conduit of a booster venturi"). But Howes' fuel pipe is a stationary fuel jet, not a booster-venturi support conduit, and the sleeve lacks the stepped outer surfaces, shoulder, and positioning cord. Does not fully anticipate claim 15; close on claim 16 but the "support conduit of a booster venturi" limitation is not met (see Abbey '685 for the booster-venturi teaching).
  • Claims 1/6: No stepped-bore/shoulder seating; no alignment means. No anticipation.
  • Net: Second-most-relevant sleeve reference. Strong § 103 art when combined with Lorusso (removable liner) and Abbey '685 (booster in the venturi).

3. US 4,387,685 — Abbey, "Fluidic control system including variable venturi"

• Full citation: H. G. Abbey, US 4,387,685 A. Filed 1976-10-08; issued 1983-06-14; US 4,387,685 B1 reexamination certificate 1998-02-03 (the 9th "patent citation").
• Status: § 102(b) art as to the 1983 patent. (The B1 date, 1998, is after the '470 filing, so the B1 is not itself § 102(b) art; it merely confirms the '685 claims survived reexamination.)
• Description (verified): A variable-venturi structure — cylindrical casing with a coaxially disposed cylindrical booster having a venturi formation (primary passage), an axially shiftable spool (variable secondary passage), and a tertiary passage between spool and casing. Notably the specification states: "air flows into the carburetor through a Venturi tube and a fuel nozzle within a booster Venturi concentric with the main Venturi tube."
• Potential § 102 impact:
  • Claims 11, 12, 14 (booster venturi with ring nozzle suspended in the throat; axially offset constrictions producing overlapping low-pressure zones): Abbey '685 discloses the concentric booster venturi in the main venturi concept and fuels/nozzles within it. It does not disclose a ring nozzle suspended by a support conduit passing through a side opening in a removable sleeve, nor the specific axially-offset overlapping constriction geometry as claimed. Relevant § 103 art, not a clean § 102 reference.
  • Claims 3/13/17: Variable (moving) venturi, not fixed throats in a contoured bowl. No anticipation.
  • Net: Most relevant to the booster-venturi dependent claims; background art for the mainstream.

4. US 4,250,856 — Abbey, "Fuel-air ratio automatic control system using variable venturi structure"

• Full citation: H. G. Abbey, US 4,250,856 A. Filed 1980-01-25; issued 1981-02-17. CIP of Ser. 962,883 (now US 4,187,805) and Ser. 919,541 (1978).
• Status: § 102(b) art.
• Description (verified): A closed-loop, servo-controlled variable-venturi carburetor. Claim 2 recites "a cylindrical booster whose interior surface has a Venturi formation," claim 3 "a ring having a Venturi formation," and the spec discusses dispersing fuel in air to promote vaporization and the classic converging-inlet → throat → diverging-outlet venturi.
• Potential § 102 impact:
  • Claim 3 / venturi-throat claims: discloses converging/throat/diverging venturi passages generating a low-pressure zone, but in a variable-geometry, servo-driven device without the claimed contoured bowl flow-director surfaces coextensive with the inlet. No anticipation.
  • Claim 11 (booster/ring nozzle) & 12/14 (offset constrictions): tangent (booster + ring venturi formation); does not disclose support-conduit suspension through a sleeve side opening or the specific offset. § 103 art.
  • Net: Background/§ 103, strongest on the booster-ring concept.

5. US 4,808,007 — Komax Systems, "Dual viscosity mixer"

• Full citation: Komax Systems, Inc., US 4,808,007 A. Filed 1982-05-13; issued 1989-02-28.
• Status: § 102(b) art.
• Description (content unverified in my searches): A static mixer for combining two fluids of differing viscosity, using an in-line flow passage with mixing/deflecting elements.
• Potential § 102 impact: Directed to a non-analogous fluid-mixing device, not a carburetor. It cannot anticipate any '470 claim (no carburetor body, bores, venturi sleeves, or bowl). It is, at most, evidence that contoured flow-directing surfaces in a conduit were known, i.e., § 103 background against the flow-director-surface concept in claims 3/13/17 — and weakly so. No claim anticipated.

6. JP S63-9665 — Nippon Carbureter Co., Ltd., "Carburetor" (Kokai)

• Full citation: Japanese published application JP S63-9665 A. Filed 1986-06-30; published 1988-01-16.
• Status: § 102(b) foreign printed publication.
• Description (content unverified): A carburetor (title and assignee as listed). I could not retrieve the disclosure.
• Potential § 102 impact: Cannot be assessed in detail without the text. Based on title alone it is background carburetor art relevant at most to the generic venturi-throat claims (3, 13, 17). I cannot assert it anticipates any claim, and I will not speculate about its contents.

7. DE 1008052 B — Soc. Ind. de Brevets et d'Etudes, "Composite carburetor"

• Full citation: DE 1008052 B. Priority 1955-08-05; published 1957-05-09.
• Status: § 102(b) foreign printed publication.
• Description (content unverified): A "composite carburetor" — the title indicates an assembled, multi-component carburetor.
• Potential § 102 impact: Very old, foreign-language, and I could not verify its disclosure. A "composite" carburetor may be relevant to the notion of a carburetor built from inserted components, but that is speculation. No claim can be mapped with confidence. Best treated as general background; possibly § 103 art if it shows a venturi formed by a separate insert.

8. US 5,667,730 — Barfield, "Float bowl attachment for carburetor"

• Full citation: M. R. Barfield, US 5,667,730 A. Filed 1995-09-13; issued 1997-09-16.
• Status: § 102(e) only (its Sept. 13, 1995 filing date precedes the '470 priority date of Feb. 13, 1996; it is not § 102(b) because it issued after the critical date).
• Description (verified): A float-bowl spacer/attachment (with float, needle-and-seat valve, accelerator-pump injector) that lets a gasoline carburetor run alcohol by enlarging fuel capacity/bowl volume.
• Potential § 102 impact: Directed to fuel delivery/float-bowl capacity, not to venturi sleeves or bowl flow-director surfaces. It cannot anticipate any '470 claim — no shared inventive subject matter. It is at most broad, non-analogous "carburetor structure" art. No claim anticipated.

The three non-patent citations

NPL-1 & NPL-2 (same item, listed twice): HP Books, Weber Carburetors, Pat Braden (1988)

• Status: § 102(b) printed publication (1988, well before the Feb. 13, 1995 critical date).
• Relevance: This is likely the most legally significant citation in the entire list, because Weber DCOE/IDA-type carburetors are the archetype of a carburetor with removable/ interchangeable venturi ("choke") tubes seated in the barrel, and with a contoured air-horn/bowl feeding them. If the book shows a removable venturi insert of stepped outer diameter seated against a shoulder — or an air horn contoured into the venturi inlet — it is direct § 102(b) art against the sleeve claims (15) and the bowl-surface claims (3/17).
• Potential § 102 impact: Flagged as high-priority for claim 15 and claims 3/17, subject to confirming the exact figures/text — which I could not do here. Treat as a lead to verify against the book itself.

NPL-3: Performance Racing Industry Magazine, p. 28 ("Twisted Wedge Aluminum Cylinder Heads…," undated)

• Status: Date uncertain — the citation is expressly "undated." An undated periodical cannot be assigned to § 102(b) without establishing its publication date.
• Potential § 102 impact: The subject matter (cylinder heads by Trick Flow) appears unrelated to carburetor venturi sleeves or bowl geometry. It is almost certainly cited as general high-performance-aftermarket background, and it does not anticipate any claim.

Ranking of the most relevant prior art

Bottom line

• No single cited reference anticipates any independent claim of US 5,863,470, on the disclosures I could verify. Anticipation fails because at least one limitation is missing from each reference relative to each independent claim's full element set — most often the combination of (i) the stepped outer sleeve surfaces + external shoulder + "positioning cord" alignment (claims 1, 6, 8, 15) and (ii) the bowl concave flow-director surfaces coextensive with the converging inlet (claims 1, 2, 3, 13, 17).
• The most dangerous references are US 4,966,735 (Lorusso) and US 4,235,828 (Howes), ideally combined with the Weber book and Abbey '685 — i.e., the real threat to validity is a § 103 obviousness attack built from (removable venturi liner) + (side-slot insert) + (booster-in-venturi), not a § 102 anticipation.
• US 5,667,730 (Barfield) is available only under § 102(e) and is non-anticipatory as to every claim; US 4,808,007 (Komax) and the undated PRI magazine page are effectively irrelevant to the claimed subject matter.
• I could not verify the disclosures of DE 1008052 B, JP S63-9665, or US 4,808,007, and I have not located any 2026 CAFC activity naming US 5,863,470 (consistent with the earlier-generated section). The patent is expired (anticipated expiration Feb. 14, 2017), so this prior-art picture is of historical/validity-interest only.

Key URLs used: US 5,863,470 full text — https://patents.google.com/patent/US5863470/en ; US 4,235,828 — https://patents.google.com/patent/US4235828 ; US 4,250,856 — https://patents.google.com/patent/US4250856 ; US 4,387,685 — https://patents.google.com/patent/US4387685 ; US 4,966,735 — https://patents.google.com/patent/US4966735 ; US 5,667,730 — https://patents.google.com/patent/US5667730 (and https://patents.justia.com/patent/[5667730](/patent/5667730)).

I'll ground this analysis by pulling details on the cited prior-art references before building the §103 combinations.

Obviousness Analysis — U.S. Patent No. 5,863,470 under 35 U.S.C. § 103

Built on the prior sections (bibliographic data, claim-by-claim summary, and litigation findings). I do not repeat those except where a cross-reference is needed. No contradiction between those sections and the record I relied on here.

Note on dates. The current date given for this task is April 26, 2026. The '470 patent is pre-AIA, so § 103(a) as it existed before the AIA governs, with KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) supplying the operative flexible standard. Critical date: Feb. 13, 1996 (provisional 60/011,550); actual filing Feb. 14, 1997; issue Jan. 26, 1999.

Sourcing rule. Per the task instruction, I used the references listed in the Prior Art / Citations section of the Google Patents record for US 5,863,470. I retrieved substantive text for four of them (Howes '828, Lorusso '735, Abbey '685/'856, Komax '007). For DE 1008052 B, JP S63-9665, US 5,667,730 (Barfield), and the two NPL items I could not retrieve the disclosures before my search budget was exhausted. I mark those below and do not attribute specific teachings to them.

1. What the cited art actually teaches (verified vs. unverified)

Level of ordinary skill (proposed). A person with a mechanical-engineering or automotive-engineering background and roughly 2–4 years' experience in carburetor design/manufacture, or a skilled carburetor technician with substantial hands-on racing-carburetor build/tuning experience. This is a mature, crowded, mechanical art — which raises obviousness risk across the board.

2. Claim-by-claim obviousness analysis

Group A — The sleeve-as-a-part claims (claim 15; claim 16)

Proposed combination: Lorusso '735 + Howes '828 (optionally + the Weber NPL).

Motivation to combine. (i) Express statement of objective in Lorusso: interchangeable venturis "such that many driving conditions can be quickly accommodated." (ii) Express recognition of the problem (entry turbulence) in Lorusso, plus Howes' stated object of "reduced venturi size to increase fuel injection and turbulence." (iii) Manufacturing-cost rationale — the '470 specification itself frames the invention as avoiding the expense of machining a cast venturi; that is a business/mfg. motivation courts routinely credit, and Lorusso had already articulated the field's movement toward liners. (iv) Predictable result: a sleeve with stepped outer diameters seated on a bore ledge performs the same function it did in Lorusso, with the only addition (the cord) being a known anti-rotation expedient.

Assessment. Claim 15 is at substantial risk on Lorusso + Howes, but the positioning cord is the limitation most likely to preserve it. If the Weber NPL or another reference shows a notched/keyed insert, the risk rises sharply. Claim 16 is at high risk — Howes appears to anticipate that side-opening concept outright.

Group B — Stepped bore, shoulder seating, and retainer (claims 1, 6, 15)

Proposed combination: Lorusso '735 + Howes '828 + the ordinary skill of a carburetor designer, with DE 1008052 (if verified) supplying composite/multi-part body construction.

• Two-diameter bore with an internal shoulder and a sleeve with a complementary external shoulder is a textbook locating/seating arrangement (a counterbore with a stop face). Lorusso's bores/liners are dimensioned so that the liner is "precisely and removably fitted," and the liner ends engage the body/throttle assembly; the "means for holding the sleeves in the bores" (claim 1's retainer plate 68 with screws 72; claim 6's holding means) corresponds to any bolted cap/retainer plate, which is the ordinary way to capture inserts held under an existing stud or air-cleaner mount — and Howes shows the carburetor's air-filter mounting cylinder 14 bolted to a flange 15/17 with "bolts 16… fastened to the top of flange 17."
• Motivation: Lorusso's expressed interchangeability objective; the need to prevent the insert from being drawn downstream by engine airflow (a retention requirement intrinsic to the function); minimization of machining cost. KSR permits reliance on the "known technique to improve similar devices in the same way" and on design incentives in a predictable art.
• Assessment. For claims 1 and 6, the sleeve + bore + shoulder + retention combination is plausibly obvious. The features that resist the theory in claim 1 are (a) four bores (four-barrel carburetors were standard) and (b) the concave flow director surfaces coextensive with the converging surfaces — addressed in Group C. Note that claim 6 does not require the bowl contours, which makes claim 6 the more exposed of the two. The counter to obviousness on claim 6 is the alignment means — again the positioning cord.

Group C — Bowl flow director surfaces / coextensive contour (claims 2, 3, 4, 5, 13, 17, 18, 19; and the bowl limitation of claim 1)

Proposed combination: Abbey '685/'856 (converging inlet "free of discontinuities"; booster concentric in the main venturi; multi-barrel parallel architecture) + Lorusso '735 (express problem statement: entry turbulence losses at the venturis) + Howes '828 (air-filter mounting rim over the throat) — with the "ridges between concave surfaces" limitation resting on the ordinary skill and on the inherent geometry of a multi-bore casting.

• The problem is expressly recited in the art. Lorusso: "there are losses due to turbulences as the air enters the venturis." Under KSR and its progeny, an express identification of the problem in a prior-art reference is powerful motivation to adopt the solution the '470 claims (a smooth, decreasing-curvature transition from the manifold/bowl into each throat). Abbey '685's "converging inlet… free of discontinuities" supplies the solution concept directly, albeit for a variable venturi.
• "Substantially coextensive" (claim 1/2/3/17) — the patent's own specification concedes the point by framing this as "a streamlined contour… tends to reduce the number of changes of direction": a result-effective, geometry-level parameter, i.e., the classic obvious-design-choice category. A "surface aligned with and merging into the venturi inlet" is the definition of a fairing/fillet — a routine engineering expedient to reduce entry loss.
• Claims 4 and 5 / ridges (claims 2, 5, 10, 13, 19). "Concave surface completely surrounds the throat" (claim 4) and "ridges extending radially from a central portion between the throats" (claim 5, 10, 19) are essentially descriptions of a multi-bore carburetor bowl casting in which material must exist between adjacent bores. A machined or cast four-bore manifold bowl with a central air-cleaner stud boss (Howes' cylinder 14/central mounting; Lorusso's central stud 28… used for fastening the air filter) will inherently present ridges/walls between the bores. Inherency + design choice is a viable § 103 theory here, but see the caveat below.
• Claim 17 adds only the perimeter rim for supporting an air filter, which Howes '828 discloses (air filter mounting 13/cylinder 14/flange 15 over the throat).
• Claim 18 (sleeves inserted in bores form the throats) falls with Groups A/B.

Assessment and honest caveat. This is the group where my evidentiary picture is thinnest. I did not find a verified reference that expressly discloses a carburetor manifold bowl with a plurality of concave flow-director surfaces each surrounding one throat, coextensive with the throat's converging inlet, and separated by ridges. The obviousness argument is therefore inferential (problem recognized in the art + routine smooth-transition design + inherent multi-bore casting geometry + air-cleaner rim known). Whether that inference carries depends on facts I cannot verify: whether the DE 1008052 / JP S63‑9665 disclosures (both unretrieved) show bowl-to-throat contouring, and whether the Weber NPL illustrates bowl/venturi-transition geometry. This group is the patent's most defensible subject matter, principally claims 2, 13, and 17 as issued.

Group D — Booster venturi suspended in the sleeve, with axially offset, overlapping low-pressure zones (claims 11, 12, 14, 16)

Proposed combination: Howes '828 + Abbey '685/'856.

• Howes '828 supplies the structural interface: a removable sleeve with a slotted side, with the fuel pipe passing through the slot into the center of the sleeve's venturi — i.e., a conduit mounted to the carburetor body and extending through a side opening of the sleeve, terminating in the sleeve's throat. That is claim 11's support-conduit-through-the-sleeve-opening architecture and claim 16's side opening.
• Abbey '685 supplies the fuel-delivery element and its placement: "a fuel nozzle within a booster Venturi concentric with the main Venturi tube"; "a cylindrical booster coaxially disposed therein… two concentric venturis in a step arrangement"; and the series of primary/secondary/tertiary passages generating sequential low-pressure zones. That is claim 11's ring nozzle suspended in the passage and claim 12/14's "overlapping zones of reduced air pressure" from axially displaced constrictions.
• Motivation. (i) Abbey '856's own explanation of why multiple venturis in series are used — "the added Venturis build up air velocity in the smaller primary Venturi, thereby augmenting the force available at the main nozzle" and the bypass air "forms an air cushion… preventing fuel from engaging the carburetor walls" — is a performance rationale directly pertinent to the problem Lorusso identifies (entry turbulence, poor distribution). (ii) Both Howes and Abbey are directed to improved fuel atomization/turbulence in carburetor induction — same field, same problem. (iii) Making the offset between the two constrictions an axial distance (claim 12) is a result-effective variable obtainable by routine experimentation.
• Assessment. Claims 11, 12, 14, and 16 are at high obviousness risk — arguably the weakest claims in the patent, because the sleeve's slotted side (Howes) and the concentric booster in the throat (Abbey) are individually known and combine with a stated, predictable engineering benefit.
• Caveat. Abbey's booster is inside an axially movable spool (variable venturi), not a fixed sleeve. A challenger must argue that fixing the geometry while retaining the concentric booster cancels no more than the variable-tuning function — which is a straightforward argument but not airtight.

Group E — Alignment means / "positioning cord" (claims 6, 8, 15)

This is the patent's likely point of novelty and the hardest group to invalidate on the cited record.

• I found no verified one-reference or two-reference teaching of "a positioning cord formed in the lower outer cylindrical surface… sized and shaped to abut the positioning cord of an adjacent venturi sleeve" so that adjacent sleeves lock each other against rotation. Its cleverness is that it uses the neighboring sleeve as the keyway, rather than the body.
• Available § 103 theory (argument, not proof): (i) indexing/keying inserts against rotation is a known technique; (ii) Here the function (aligning the sleeve's side slot with the booster support conduit) is a known requirement — Lorusso and Howes both require ports/slots to line up with a fuel passage; (iii) an artisan would foresee that eliminating a body-side keyway (by using a flat on the OD that bears on the adjacent sleeve) is a simplification with predictable results; (iv) in a four-bore rectangular cluster, adjacency is inherent. Under KSR's "predictable variations" and "known technique" rationales, this could be rendered obvious — but the combination reference proving the flat-to-flat abutment as an anti-rotation method is missing from the cited record.
• Assessment. Claims 6, 8, and 15 (to the extent they turn on the positioning cord) present the best non-obviousness posture. Note the tension: claim 6 is otherwise exposed (no bowl requirement), so the cord is doing all the work.

3. Cross-cutting motivations a challenger would marshal

1. Same field / same problem. All of Howes, Lorusso, and Abbey are carburetors for air-fuel induction in spark-ignition engines; Howes and Abbey in particular target atomization, turbulence, and distribution. Lorusso targets adaptability to driving conditions and entry turbulence. KSR requires only that the references be from the same field of endeavor or reasonably pertinent to the problem.
2. Express statement of the interchangeability objective in Lorusso ('735) — notably, an object-of-the-invention statement, which is the strongest form of motivation-of-combination evidence.
3. Express statement of the turbulence-at-the-inlet problem in Lorusso, combined with Abbey's "free of discontinuities" inlet — problem + solution both in the art.
4. Cost-of-manufacture rationale (the '470's own stated motivation: cast venturis cannot be precision-machined economically; a machined billet sleeve in a standard cast body is cheaper). Business/mfg. incentives are cognizable.
5. Predictable, result-effective geometry. "Coextensive," "converging," "axially offset a distance to form overlapping zones" are all parameters a designer tunes by routine experimentation — the classic "obvious to try" posture, especially with only a finite number of identified, predictable solutions (KSR).
6. Known keying/indexing of inserts (for Group E), absent a specific reference.

4. Where the obviousness case is strong vs. weak (bottom line)

Corollary. The patent's defensibility rests substantially on two features: (a) the bowl/venturi coextensive contour with inter-throat ridges (claims 2, 13, 17 and the corresponding limitation of claim 1) and (b) the inter-sleeve "positioning cord" alignment (claims 6, 8, 15). The "replaceable sleeve per se" concept (claim 15 as a part; claims 16, 11–14) is the most exposed subject matter, because Lorusso and Howes together disclose replaceable venturi inserts of differing dimensions and a slotted sleeve receiving the fuel conduit.

5. Explicit limits on this analysis

• Unverified references. DE 1008052 B, JP S63‑9665, US 5,667,730 (Barfield), and both NPL items were not retrieved. Any of them could strengthen the case (if DE 1008052 shows a multi-part carburetor body, or the Weber NPL shows a keyed/notched replaceable choke tube with a bowl transition contour) or be irrelevant. No conclusion here depends on their content.
• Non-analogous art. Komax '007 is polymer-processing apparatus. Its use requires an analogous-art showing ("reasonably pertinent to the particular problem"). I would not build a combination on it; treat it as corroborative of constriction geometry only.
• Partial text retrieval. My reads of Howes, Lorusso, and Abbey are from excerpts, not the full specifications and claims. In particular, I could not confirm whether Lorusso's liners include any anti-rotation feature, nor the exact retention hardware in Lorusso (the '735 excerpt shows bolted assembly and a central air-filter stud, but I did not verify a retainer plate over the liner ends).
• Presumption of validity / examiner consideration. Every reference above was before the examiner on the '470 face. Issuance over them means the examiner either did not combine them or considered the combination insufficient. That does not defeat a § 103 challenge, but it is a real evidentiary headwind, and it suggests the examiner likely treated the bowl-contour and alignment features as the distinguishing subject matter — consistent with my strength/weakness mapping.
• Enforcement irrelevance. The patent is Expired – Lifetime (anticipated expiration Feb. 14, 2017 per the record), so it cannot be asserted for ongoing infringement. This analysis is therefore defensive/validity-diagnostic (e.g., for freedom-to-operate or IP-schedule diligence), not an infringement posture. My prior litigation section found no litigation involving the '470 patent; the 2026 Holley Performance Products v. Aces Fuel Injection E.D. Tenn. matter remains an unconfirmed open item — if it is ever reviewed, an expired patent cannot be the asserted instrument, so the '470's claims are relevant there only as prior art or background.
• This is technical patent analysis, not legal advice, and not an opinion of validity or invalidity suitable for certification in a proceeding. A definitive § 103 opinion would require full-text retrieval of the five unverified references, the '470's file history (applicant remarks and any Rule 132 declarations), and consideration of objective indicia (commercial success, long-felt need, copying) that I have no evidence for.

No contradictions surfaced between this analysis and the previously generated sections. One clarification worth stating, in case it is misread later: the earlier section's note that the "positioning cord" phrasing may be a drafting artifact does not bear on claim construction for § 103 purposes — the term is used consistently in the specification and claims, and I analyzed it literally as instructed.