US 1478152

I'll verify the patent record and check for any litigation or docket activity before summarizing.

Let me do a couple more targeted checks for the US patent and any docket/litigation record.

Verification notes first

Two cautions before the summary:

1. Searches for "1478152" without the US prefix return unrelated documents. The bare number 1478152 surfaced CN1478152A ("Coating device") and EP1478152A3 ("Mobile unit, data transmission/reception method…"). Neither is US 1,478,152. Per your strict rule, I have not merged these; they are different documents on different numbers/authorities.
2. No litigation, PTAB, or CAFC activity found. I ran searches aimed at USPTO records and CAFC 2026 dockets for this patent. Nothing connected to US 1,478,152 appeared. This is entirely expected: the patent is a 1923-issued, 17-year-term document that expired December 18, 1940, roughly 85 years before any 2026 docket could exist. I found no evidence of any suit ever having been filed on this patent, and I cannot confirm one way or the other from the sources available — treat "no litigation" as an absence of evidence, not a verified negative.

Everything below is taken from the authoritative full text you supplied (Google Patents, https://patents.google.com/patent/US1478152/en), cross-checked against my searches.

Bibliographic data — US 1,478,152

Discrepancy to flag (I am not auto-correcting it): the OCR'd front-page text of the printed patent reads "Filed Oct. 25. 1919" and again "Filed Oct. 26 1919," whereas the structured bibliographic metadata states 1919-10-23 and repeats 1919-10-23 for the priority date. These are inconsistent in the source itself; I am reporting both rather than resolving them.

Abstract: There is no formal abstract. US patents of this era did not carry one. What Google renders as an "Abstract" is in fact the patent's own Definitions block, whose operative sentences are its two stated objects: (a) novel means for supplying an accelerating quantity of fuel; and (b) a carburetor with cooperative means to supply fuel charges for ordinary running, for idling, and to supply a limited accelerating quantity of fuel for a richer mixture "as when starting or accelerating the speed of the motor."

Claims: count and structure

The patent has exactly one claim. It is independent. There are no dependent claims and no other claim set. This is the entire claim section as issued:

"In a carburetor, the combination of a constant level fuel chamber, a tube, an oscillating throttle valve in said tube having a stem extending into said constant level fuel chamber, an accelerating well eccentrically mounted upon the stem of the valve which extends into the constant level fuel chamber, said accelerating well having an inlet port adapted to maintain the liquid level therein the same as the liquid level in the constant level fuel chamber, said stem of the throttle valve having a passageway therein establishing communication between the accelerating well and said tube, said accelerating well being adapted to rotate with said valve so that when said valve is opened the inlet port of the accelerating well will be above the level of the liquid fuel in the constant level fuel chamber and the level of liquid fuel within the accelerating well will be considerably higher than the level of the fuel in the constant level fuel chamber, whereby the liquid in said accelerating well will feed its limited supply through the passageway of said valve stem to said tube."

Plain-language overview of the sole claim

It is a single combination claim for a purely mechanical acceleration-enrichment device. Reading it element by element:

1. A constant-level fuel chamber — the float bowl (reference 15), kept at a fixed level by a float-actuated needle valve (17/18).
2. A tube — the air/mixture conduit (19) through which engine suction draws air.
3. An oscillating throttle valve in the tube, with a stem reaching down into the fuel chamber — the ellipsoidal butterfly/plug valve (23) on stem 22, operated by lever 25.
4. An "accelerating well" mounted eccentrically on that valve stem, positioned down inside the float bowl — a small limited-capacity cup (43) fastened off-center to the stem (42), so that it swings as the throttle rotates.
5. The well has an inlet port that keeps its internal fuel level equal to the bowl's level — a calibrated inlet (44, with a removable calibrated plug 50) sized so inflow matches outflow, so at rest the well is simply a submerged, level-equalized reservoir.
6. A passageway in the valve stem connects the well to the tube — passage 45 running up the stem to an outlet port 46 discharging into the air tube.
7. The well rotates with the valve, so opening the throttle lifts the inlet port above the bowl fuel level, and the fuel level inside the well becomes considerably higher than the bowl level — this is the functional heart of the claim. Rotating the eccentric well acts like tipping a ladle: the well is lifted while still holding its measured charge of fuel, producing a temporary static head above the bowl level.
8. Result: the well feeds its limited supply through the stem passageway into the tube — a one-shot, self-limiting extra charge of fuel for acceleration, which (per the specification) is not replenished until the throttle again closes far enough to re-submerge the inlet port.

Bottom line on scope: the claim is narrowly drawn to the combination of (i) an oscillating throttle valve whose stem penetrates the float bowl, (ii) an eccentrically mounted well on that stem, (iii) an equalizing inlet port, and (iv) a fuel passage through the stem — with the eccentric rotation producing a transient head of fuel. The novelty is the mechanical "tilted well as acceleration pump" concept; it contains no electronic, vacuum-diaphragm, or pump-plunger limitations, and no separate pump element at all.

Embodiment context supporting the claim (from the specification)

• Fuel path for normal running: bowl → passage 20 → circumferential groove 21 → passage through stem 22 and valve 23 → branch port 31 on the convex face 28.
• Idling path: port 32 → recess 33 in adjustable air screw 34 → transverse openings 36 → by-pass 37 → restricted port 39 governed by screw 40.
• Convex valve face 28 is stated to speed up airflow over the ports at low engine speed; Figure 12 shows a modified valve (61/63) with greater convexity on the opposite face to constrict the passage below the valve and force air over the ports.
• Ports 31, 32, 44 and 46 are all fitted with interchangeable threaded "calibrating plugs" 50 having pre-sized orifices 52 — the stated purpose being to adapt one carburetor casting to different engines rather than making a special carburetor per engine type.
• Port 46 is specified as larger than ports 31 and 32 so the accelerating charge can flow freely and enrich the mixture long enough to accelerate the engine.

What I could not confirm

• No record of any assignment or corporate ownership. The sources list "Individual" for both original and current assignee. If Voegtle assigned the patent later, I did not find it.
• No litigation, interference, or post-issuance proceeding involving this patent. The one semi-related result my searches returned was a Jorgensen/Ericson interference narrative concerning unrelated carburetor patents (e.g., Ericson 1,915,851, Reissue 22,742, Shaff 2,365,910) — not US 1,478,152. I am noting it only to avoid implying it is connected.
• No USPTO PatentCenter or CAFC 2026 docket entries for this patent exist as far as I can determine, and given the 1940 expiration none would be expected.

I'll search for litigation involving US patent 1478152.

Let me run more targeted searches.

Litigation Search: US Patent 1,478,152

Bottom line: I found no litigation — none at all — involving US Patent 1,478,152.

What I searched

I ran multiple targeted queries, including:

• US patent 1478152 litigation
• "1478152" patent lawsuit defendant case
• "1478152" carburetor patent infringement suit
• patent 1,478,152 Voegtle lawsuit
• Voegtle carburetor patent litigation 1920s
• Charles J Voegtle carburetor patent assigned sued

No search returned a case — plaintiff, defendant, jurisdiction, docket number, or filing date — matching this patent number. The only returns were hits on unrelated patents (e.g., a Federal Circuit opinion about U.S. Patent Nos. 4,063,063 / 4,145/145 "PMR Services" case, which involves different patent numbers entirely and which I am deliberately not conflating with 1,478,152). One query returned zero results.

Why this is expected, not surprising

The patent record itself explains the absence of litigation:

The patent expired in December 1940 — over 85 years ago. U.S. patents have a maximum term of 20 years from filing (17 years from grant under the law applicable then), and the entire enforceable life of this patent ended in 1940. Publicly indexed litigation databases (Unified Patents, PACER/CM-ECF, CourtListener/RECAP, Darts-ip) are effectively comprehensive only from roughly the 2000s forward, and in the pre-1940 era exist as scanned print reporters rather than searchable dockets. So there are two layers here:

1. No modern litigation exists — the patent has been expired and unenforceable for decades, so no infringement action could be sustained.
2. Pre-1940 litigation, if any existed (e.g., a 1920s–1930s carburetor infringement suit), is not indexed in the sources I can reach, and I found no reported decision naming this patent.

What I cannot confirm

I will state this explicitly rather than fabricate: I cannot confirm that no suit was ever filed in the 1920s or 1930s. It is possible a suit was filed and settled, dismissed without written opinion, or reported only in a print volume not captured by my searches. What I can say with confidence is:

• No case was located in any searchable litigation source.
• No party, docket number, jurisdiction, or outcome can be reported because none was found.
• The patent's single claim was directed to the combination of a constant-level fuel chamber, an oscillating throttle valve, and an eccentrically mounted accelerating well on the valve stem that rotates with the valve to create a static fuel head on opening — i.e., an accelerator-pump substitute.

Recommended next steps for a definitive answer

If you need a negative-confirmation-level answer, the following manual routes would be required (all outside what my searches could reach):

• Print digest searches — Federal Reporter (F., F.2d), USPQ, and the Decennial Digest under "Patents" for 1919–1945, searching the patent number and "Voegtle."
• Westlaw / LexisNexis / Bloomberg Law full-text historical case databases, which include scanned pre-1940 opinions.
• Darts-ip (now part of Clarivate) litigation records, which include some historical U.S. filings.
• The National Archives — original equity case files for the District of New Jersey (the inventor's residence), if you suspect a local suit.

If you'd like, I can draft the search strings to run in Westlaw/Lexis historical libraries to close this out.

Proceedings overview

Total AIA trial proceedings on US 1,478,152: zero. The canonical structured block from the USPTO Open Data Portal lists no IPR, PGR, or CBM proceeding, and targeted web searches (Google Patents family/litigation data, open-web queries on the patent number, the title "Carburetor," and the inventor "Charles J. Voegtle") surfaced no PTAB filings, no PTAB Final Written Decisions, and no Federal Circuit appeals involving this patent. The breakdown is therefore 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials. The defensive posture is not "hardened by victory" and not "claims already canceled" — it is moot: the patent's entire term expired on 1940-12-18, so there is no live claim for any defendant to infringe and no AIA vehicle realistically available to reach the Board.

For completeness, the enumerated bases for AIA review each fail here:

Sources reviewed: US1478152A on Google Patents (structured family, legal-status, and "Cited By" data); USPTO PTAB Decisions / E2E for any Board paper bearing this patent number; open-web searches for "1478152" IPR, Voegtle carburetor PTAB, and the like.

Proceedings

None. There are no proceeding numbers to report, and I will not manufacture any. For the record, the relevant public trails I checked and what they showed:

No proceeding — no IPR/PGR/CBM docket entry

• Type: N/A
• Filed: N/A
• Status: N/A — the structured "PTAB proceedings on file" block is empty, and the ODP ingest reflects no AIA trial activity.
• Judge panel: None. No APJs have ever touched this patent in an AIA trial.
• Petition grounds: None. No § 102 / § 103 / § 112 grounds of any kind have been advanced at the Board.
• Institution decision: None issued. Nothing was instituted; nothing was denied.
• Final Written Decision: None. No claim of this patent has ever been canceled or sustained in an AIA trial. The patent as issued remains textually intact — which is unsurprising, because it has been expired for roughly 85 years.
• Settlement / termination: None.
• Appeal: None. No CAFC docket number exists for this patent; searches of Federal Circuit materials and CourtListener returned nothing tied to US 1,478,152 or to Voegtle as a patent owner or appellant.
• Defensive value: Zero litigation value and zero risk. If someone puts US 1,478,152 in front of you as an asserted patent, the response is not an IPR strategy — it is a one-paragraph letter citing the 1940-12-18 expiration and the resulting absence of any enforceable claim. Any demand letter citing this patent's claim is defective on its face; this is a fair candidate for a Rule 11 or state-bar letter rather than a validity challenge.

One factual note worth flagging because it cuts against the "claims 1–5" framing in the task template: this patent does not have multiple claims. The printed specification ends with a single claim ("I claim: In a carburetor, the combination of a constant level fuel chamber, a tube, an oscillating throttle valve…"), directed to the eccentrically-mounted accelerating well that rotates with the throttle valve so that opening the valve lifts the well's inlet port above the constant-level float-bowl level and creates a static head of fuel. There is no claim 2, much less a claim 5, so any assertion purporting to rest on "claims 1–5" of this patent is citing claims that do not exist.

Strategic summary

Claim status. The single claim of US 1,478,152 is UNTESTED at the PTAB — not canceled, not sustained, simply never challenged. But "untested" here does not mean "unresolved risk." The claim was granted on 1923-12-18 on a 1919-10-23 pre-AIA filing and expired on 1940-12-18. No claim of this patent is enforceable today, so there is no CANCELED / SUSTAINED split to report and no surviving-claim set to enumerate.

Estoppel landscape. § 315(e)(2) estoppel is inapplicable. Estoppel attaches to a petitioner who has been in an IPR that reached a final written decision; no one has ever petitioned, so no one is estopped, and correspondingly no prior-art ground is "used up." The practical consequence is the reverse of the usual estoppel story: a defendant today has every prior-art ground available in district court, unconstrained by § 315(e)(2) — but that freedom is academic, because the invalidity fight, like the infringement fight, is over before it starts. The 85-year gap between expiration and today also means that any 1919–1940 prior art, the file history, and the contemporaneous carburetor art (e.g., the 1921 Boyce reference, US 1,383,044, and the later accumulated art) remain untouched and fully usable if a district court needed them for some collateral purpose, such as a Walker Process or inequitable-conduct theory about the assertion itself.

Pattern signals. None of the usual patterns appear. There is no repeat petitioner, because there is no petitioner at all. The patent owner — originally an individual, Charles J. Voegtle of West Hoboken, New Jersey, with no assigned corporate owner — has never appealed anything to the Federal Circuit. No defensive aggregator (Unified Patents, RPX, etc.) has ever touched this patent, which is expected: aggregators exist to clear live patents, and this one has been in the public domain since before Pearl Harbor. The only public trace of third-party interest is a single forward citation, US 2,833,530 to General Motors ("Fluid mixing means," 1958), which is a citation, not a challenge.

Recommended next steps

If you are a defendant and a demand letter cites US 1,478,152: there is no FWD to link to, because none exists — do not tell anyone the claims were invalidated, because no tribunal ever did that. What you link and quote instead is the patent's own record and date arithmetic:

• US1478152A on Google Patents — the record shows Priority date 1919-10-23, Publication/grant 1923-12-18, and "1940-12-18 Anticipated expiration," legal status "Expired - Lifetime." That is the entire defensive case.
• The printed claim is a single claim (not claims 1–5). Confirm in the letter that the patent contains one claim, and that its 17-year pre-URAA term ran out on 1940-12-18. Nothing has revived it: the record shows no reissue, no extension, and no terminal disclaimer activity.
• Treat the assertion as a bad-faith demand. A patent that has been expired for 85 years cannot be infringed, and a letter threatening suit on it is strong material for a fee-shifting or disciplinary response.

If you were hoping for an IPR: do not file one. It would be a waste of the filing fee and, more importantly, an admission that you think the patent has life. There is no institution decision deadline to track, no oral hearing on the horizon, and no FWD due date — the trial-stage milestones in the task template presuppose a pending proceeding, and there is none.

Bottom line: the absence of PTAB activity on US 1,478,152 is not the "well-asserted patents eventually attract IPRs" signal. It is the opposite signal — this is a 1919/1923 patent that expired in 1940-12-18, has one claim, and has never been worth one minute of anyone's litigation budget. I state plainly that I found no PTAB proceedings and no Federal Circuit appeals, and I have not invented proceeding numbers to fill the template.

I'll verify the assignment record status before writing, since the authoritative text shows no post-issuance transfer entries.

Inventors

Charles J. Voegtle — sole named inventor. Residence of record: West Hoboken, Hudson County, New Jersey (per the specification's "To all whom it may concern" paragraph: "CHARLES J. VOEGTLE, OF WEST HOBOKEN, NEW JERSEY"). He is identified as a citizen of the United States.

• Employer at time of filing: not determinable. The specification names no corporate employer, and the patent issued with the inventor himself as the sole owner of record (Google Patents lists both "Original Assignee" and "Current Assignee" as Individual, which is its placeholder for "no assignable entity on the face of the patent"). A pre-AIA application filed and issued in the sole inventor's name, with no assignment recorded at issuance, points to an independent inventor rather than an employee-invention assignment.
• Unusual patterns: none observable. There is no evidence of a group of co-inventors departing a common corporate assignee, no continuity/divisional family, and no co-inventor group at all. The "fire-sale precursor" pattern you asked me to look for requires co-inventors exiting a shared corporate assignee; that fact pattern is structurally absent here.

Original assignee

There is no original assignee. US 1,478,152 issued to Charles J. Voegtle individually on 1923-12-18 (application US 332,579, filed 1919-10-23). The patent's own claim closes with "CHARLES J. VOEGTLE" as the claimant-signatory, and the Google Patents bibliographic record shows Individual as both original and current assignee.

• Product embodying the claims: No evidence located that Voegtle manufactured or sold a carburetor embodying this claim. The invention is a single-claim mechanical carburetor (an oscillating throttle valve carrying a rocking "accelerating well" on its stem), and I found no trace of a Voegtle carburetor product line, catalog, or trade press reference.
• Primary line of business: Not determinable from the record. West Hoboken, N.J. in 1919 was not an automotive-parts manufacturing center, which is weak contextual support (not proof) for an individual-inventor filing rather than a corporate one.
• Current status: The patent expired 1940-12-18 (Google Patents legal events: "Anticipated expiration"), i.e. the full 17-year term from the 1923 grant. The patent is long dead and cannot be asserted by anyone. No information on the inventor's later status, corporate or personal, surfaced in search.

Note: the only outward citation to this patent is US 2,833,530A ("Fluid mixing means," Gen Motors Corp, 1958-05-06, citing) — that is a later patent citing this one as prior art, not an ownership transfer.

Assignment timeline

The USPTO Assignment Center shows no recorded assignments for US 1,478,152, and none appears in the Google Patents legal-events record. I am not able to supply reel/frame entries, conveyances, assignors, assignees, or correspondents of record, because no such records exist to report. Per your instruction, I will not manufacture them.

Sources checked (2026-09-29):

• Google Patents legal events for US 1,478,152 A — the complete event list is: 1919-10-23 filed / priority to US 332,579 A; 1923-12-18 granted; 1923-12-18 published; 1940-12-18 anticipated expiration. Zero assignment, security-interest, merger, change-of-name, license, or release entries. Family size: 1 (US 332,579 A only). There is no Continuation/Divisional chain to trace.
• USPTO Assignment Center search page: https://assignmentcenter.uspto.gov/ (searched by patent number 1478152; no hits)
• USPTO legacy assignment index: https://assignment.uspto.gov/patent/index.html
• Google Patents record: https://patents.google.com/patent/US1478152/en

Important evidentiary caveat on a 1919 patent: the USPTO's assignment database is only comprehensively digitized from roughly the mid-1950s forward. For a patent that lapsed in 1940, the absence of a digital assignment hit is consistent with — but not conclusive proof of — a never-assigned patent. A paper-era assignment recorded in the 1920s could exist in the physical reel archives and simply never have been imaged. I cannot verify the paper reels through the tools available to me, so treat this as "no recorded assignments surfaced," not "provably never assigned."

Stop rule

Because the Assignment Center has no records for this patent, your operating rule directs me to stop after this section. I have therefore omitted the Timeline diagram, NPE / troll-pattern signals, and Verdict sections rather than populate them with speculation. As a non-substantive note: every one of the eight NPE signals would read not present or unclear here, since there is no post-issuance chain to evaluate, and the patent has been expired since 1940-12-18, which independently forecloses assertion by any party. Verdict by construction would fall to Insufficient data (no records, or only the original assignment) — the original assignment being, in this case, no assignment at all.

If you want the full diagram and signal-by-signal table rendered anyway for form completeness, say so and I will produce it with each entry marked accordingly.

I'll start by searching for the specific patent number and its citation records.

Let me look more specifically at the citation records for this patent.

Let me try to verify whether the patent's front page or USPTO record lists any examiner-cited references.

1. Patent identified (literal identifiers)

I did not auto‑correct any identifier; the numbers above are reproduced exactly as they appear in the source record.

2. Citation inventory — what actually exists on this record

This is the critical finding, and I want to state it plainly rather than manufacture a citation list:

US1478152 has no "References Cited" / prior‑art citation section in its record. The authoritative publication record (Google Patents mirror of the USPTO/EPO data) contains:

• No examiner‑cited prior art (no "References Cited" list at all),
• No applicant‑cited references,
• No foreign patent documents or non‑patent literature listed as cited art.

This is not unusual for a 1923‑granted U.S. patent: pre‑1970s U.S. patents generally do not carry a front‑page "References Cited" block, and the printed specification of US1478152 as published contains only the description, drawings reference and the single claim — no art list.

Consequently, there are zero references on the face of US1478152 that can be mapped to 35 U.S.C. § 102. I could not identify even one anticipatory reference of record, because none exists of record. Anyone who presents a § 102 chart for this patent based on "its citations" would be inventing the citations.

3. The one actual citation on the record (a forward citation)

The record contains exactly one citation relationship, and it runs the wrong direction to be prior art:

Brief description: US2833530A concerns a fluid‑mixing arrangement in an intake duct (venturi/aspirating structure with fuel passages communicating with the throat) for preparing combustible mixtures in internal‑combustion engines.

§ 102 analysis: Cannot anticipate any claim of US1478152. Under § 102(a)/(b) (pre‑AIA) and § 102(a)(1)/(a)(2) (AIA), a reference must predate the patent's effective filing date. US2833530A has a priority date of 1955‑06‑01 and a publication date of 1958‑05‑06, both roughly 36 years after US1478152's 1919‑10‑23 filing date. It is therefore not "prior art" against US1478152 at all; the relationship is the reverse (US1478152 is potential prior art against US2833530A). It is citation evidence of field lineage only.

4. Items on the record that are not prior‑art citations

The record also lists ~25 "Similar Documents." These are algorithmic similarity hits generated by the database; they are not citations of US1478152 and carry no § 102 weight by themselves. Listed for completeness (publication number – date – title):

US2568987A 1951‑09‑25 Carburetor · US2028585A 1936‑01‑21 Carburetor · US2036205A 1936‑04‑07 Carburetor · US2319773A 1943‑05‑18 Control device · US2635625A 1953‑04‑21 Fuel supply device · US3030085A 1962‑04‑17 Fuel circuits for air‑bled carburetor · US2676004A 1954‑04‑20 Carburetor · US2399637A 1946‑05‑07 Carburetor · US2957683A 1960‑10‑25 Carburetor nozzle · US1383044A 1921‑06‑28 Carbureter for internal‑combustion engines · US2209511A 1940‑07‑30 Carburetor · US1904634A 1933‑04‑18 Charge forming device · US2512085A 1950‑06‑20 Carburetor nozzle · US2626790A 1953‑01‑27 Carburetor · US1868831A 1932‑07‑26 Carburetor · US1838675A 1931‑12‑29 Carburetor · US2182580A 1939‑12‑05 Carburetor · US1771530A 1930‑07‑29 Carbureting device · US1562806A 1925‑11‑24 Carburetor · US2828952A 1958‑04‑01 Carburetor · US1856736A 1932‑05‑03 Charge forming device · US4178331A 1979‑12‑11 Two staged carburetor with reduction of fuel spillage · US1673136A 1928‑06‑12 Carburetor · US3545417A 1970‑12‑08 Carburetor · US2810560A 1957‑10‑22 Carburetor.

Note that most of these post‑date 1919, so even taken as art they could not anticipate. The only pre‑1919 item in the list is not present; US1383044A (1921‑06‑28) is the earliest listed and still postdates the 1919‑10‑23 filing.

Family data on the record is also minimal: a single member, US332579A itself.

5. Claim‑by‑claim § 102 mapping

US1478152 has one claim. For the record, its substance is a combination of:

1. a constant‑level fuel chamber;
2. a tube;
3. an oscillating throttle valve in the tube with a stem extending into the constant‑level chamber;
4. an accelerating well eccentrically mounted on that stem, having an inlet port that maintains the well's liquid level equal to that of the constant‑level chamber;
5. a passageway in the stem communicating between the accelerating well and the tube;
6. the well rotating with the valve so that opening the valve lifts the inlet port above the chamber level, raising the head of fuel in the well so that it feeds a limited accelerating supply through the stem passageway to the tube.

§ 102 conclusion for claim 1: No reference of record can be mapped to these elements, because US1478152 has no prior‑art references of record. Anticipation of claim 1 cannot be demonstrated from the patent's citation data.

6. Where genuine prior art would have to be sought (research leads, clearly labelled as not of record)

Because the printed record is empty of citations, any true § 102/§ 103 analysis must draw on contemporaneous carburetor art from before 1919‑10‑23, e.g. constant‑level float‑chamber + accelerating‑well / auxiliary‑well arrangements. The era's carburetor‑patent litigation (notably Stromberg Motor Devices Co. v. Zenith Carburetor Co., 254 F. 1) discusses pre‑1919 U.S. and British art including the Baverey patent No. 907,953 (Dec. 29, 1908), the Crossley British patent, the Banki patent, the Ahara auxiliary‑well patent, and Schumm No. 482,201 (1892). None of these is a citation of US1478152 — I am listing them only as search leads, and I have not verified them against this patent's file history.

7. Confidence and limits

• High confidence: the bibliographic data (number, dates, inventor, single claim, forward citation US2833530A) — taken directly from the authoritative publication record supplied to me.
• High confidence: that the published record carries no "References Cited" section. This is the standard format for a 1923 U.S. patent and matches the record text I was given.
• Lower confidence / unverified: whether the original USPTO paper file wrapper for application US332579A contains an examiner's "References Cited" annotation in the handwritten/typed file or in a contemporaneous Official Gazette listing. I could not retrieve a PatentCenter document‑level "references cited" list within my search budget, so I will not assert one exists. If you have PatentCenter access, the file wrapper for US332579A is the only place such art could surface.

Bottom line: For US1478152, there is no prior‑art citation list to analyze; the sole citation of record, US2833530A (GM, 1955/1958), is a forward citation and cannot anticipate any claim under 35 U.S.C. § 102.

I'll analyze this systematically. First, let me verify the prior-art status of the references listed on the patent page and probe for pre-1919 carburetor art in the same technical space.

Let me verify the dates and disclosures of the pre-1919 candidates I've surfaced, since §103 prior-art status turns entirely on dates relative to the 1919-10-23 filing.

Obviousness Analysis — US 1,478,152 (Voegtle, "Carburetor") under 35 U.S.C. § 103

0. Three framing caveats before the merits

(a) This patent predates § 103 by three decades. Application US 332,579 was filed 1919-10-23 and the patent issued 1923-12-18 — twenty-nine years before the Patent Act of 1952 codified § 103. The contemporaneous non-obviousness standard was the judge-made "invention" requirement culminating in the "flash of genius" formulation of Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84 (1941), with roots in Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248 (1850). Any § 103 analysis here is a modern, retroactive construct (Graham factors, KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007)), applied for analytical purposes only. I flag this because a strict Cuno standard would make this claim materially harder to invalidate than a modern KSR "obvious to try" analysis would.

(b) The prior art actually printed on the Google Patents page is essentially non-probative. This is the most important finding of this exercise, and it contradicts the natural reading of that page's "Cited By" and "Similar Documents" sections:

The single possible exception is US 1,383,044 (Weiland) — published 1921-06-28 (post-filing) but, per the search result, filed June 5, 1917, Serial No. 172,847, which predates Voegtle's filing. Under pre-AIA § 102(e) it is potentially prior art as of its 1917 filing date. I could not verify the filing dates of the other "Similar Documents" within my search budget; several (e.g., US 1,776,734, US 1,777,472) are 1920s filings and would need date-checking, but on the face of the page none is pre-1919.

Consequence: a genuine § 103 analysis of this claim cannot be built from this page. All substantive references below are ones I located independently, and I have marked verification level on each.

(c) Statutory cut-offs used. Pre-AIA § 102: printed publications/patents before the invention date (§ 102(a)); public use/on sale more than one year before filing, i.e., before 1918-10-23 (§ 102(b)); US patents on applications filed before the applicant's invention date (§ 102(e)).

1. The claim, decomposed into its elements

The patent has a single claim. Its limitations, as written:

The specification adds structure not in the claim but relevant to scope: an idling jet 32 with air-bleed screw 34 (idle quality), and calibrated metering plugs 50 with orifice 52 "of such size that flow of fuel into the accelerating well 43 is equal to the discharge through the port 46" — a flow-balance teaching.

Patentability-weight note: E5 and E7–E8 are functional/result language. Under MPEP § 2114 and § 2144, a result limitation is given patentable weight where it is tied to the recited structure and depends on it. Here the "level considerably higher" result is inseparable from the recited eccentric-mounting-plus-rotation structure, so it should be given weight — it cannot be dismissed as mere intended use.

2. Candidate prior art located (with verification status)

I also encountered Stromberg Motor Devices Co. v. Zenith Carburetor Co., reported in volume 254 F. (the excerpt pages fall in the 60s–70s; I am not certain of the first page or the exact year/circuit — treat the citation as unverified). It shows that carburetor-obviousness disputes were litigated on exactly this kind of incremental combination (Crossley measuring chamber + Banki constant-level reservoir + needle valve), and that examiners repeatedly rejected claims as requiring no invention.

3. The combinations, with motivation

Combination A — Cheeseman GB 29,834 + Crossley GB 24,584 (primary)

Cheeseman supplies E1–E3, E6 (hollow spindle; passages in the valve; rotation of throttle controls fuel), and even the double-convex valve of Voegtle's Figure 12 modification. Crossley supplies E4, E5, E8 (defined-capacity chamber filling to a level and discharging its measured charge under suction).

Motivation: both references sit in the same carburetor/vaporizer art, address the same problem (proportioning fuel across the throttle range), and the Smithsonian survey documents that combining inlet types with an accelerating cup was routine practice — Burchartz combined an accelerating cup with two inlets; Thurot combined an accelerating cup with throttle-controlled succession. A POSITA seeking to improve Cheeseman's throttle-controlled fuel feed would naturally add Crossley's measured charge.

Where it fails: neither reference teaches or suggests eccentric mounting of the well on the stem, nor — critically — rotation of the well with the throttle so that its own inlet port is lifted above the float level to generate a static head. Crossley's chamber is emptied by suction; Cheeseman's passages are fixed relative to the fuel feed. E4 and E7 are unmet.

Combination B — Weiland US 1,383,044 (§ 102(e)) + Thurot US 1,158,589 / Burchartz US 1,079,634

Weiland supplies E1–E3 and E6 (conduit through the tubular stem into the throttle valve body, plus automatic enrichening). Thurot/Burchartz supply E4/E5/E8 (accelerating cup with throttle-controlled succession).

Motivation: shortening the accelerating-charge delivery path by locating the reservoir on the throttle-shaft structure; avoiding additional castings; both references are directed to preventing the identical lean-out problem.

Where it fails: identical gap — no teaching of eccentric mounting or of tilting the well to raise its inlet above the float level. Weiland's enrichening is grade-responsive, not throttle-rotation-responsive.

Combination C — Heldt textbook (accelerating well) + Cheeseman (throttle-shaft fuel passage)

This is the strongest KSR-style attack, because the textbook excerpt establishes that the accelerating well was ordinary, well-known art with a known fill-to-float-level behavior and a known extra-charge delivery. KSR permits combination of a known technique with a known structure where the improvement is a "predictable variation."

Where it fails: Voegtle's mechanism is not the textbook U-tube well at all. The textbook well delivers its extra charge because suction acts on a larger area than the metering orifice (a pressure-driven mechanism). Voegtle's delivers because the reservoir is physically lifted (a gravity/static-head mechanism). These are different physical principles, and the prior art well teaches against relying on elevation — it is designed to be emptied by suction, precisely so that elevation is irrelevant. A POSITA following the textbook would have no reason to mount the well eccentrically on the throttle shaft so that its inlet port rises above the float level.

4. Assessment

Strongest § 103 case: There is a compelling case that all the individual elements were known: constant-level chamber (universal), hollow throttle stem with fuel passages (Cheeseman 1910; Weiland 1917), idling jet above the throttle (McCarthy US 995,074, 1911), accelerating well/cup filling to float level (Crossley 1893; Burchartz 1913; Thurot 1915; textbook well), and the double-convex valve (Cheeseman). The problem to be solved — mixture impoverishment on sudden throttle opening — was expressly recognized and widely addressed in the pre-1919 art. Under KSR, "a combination of familiar elements according to known methods" yielding predictable results is obvious, and the record here shows an art so crowded that a § 103 rejection would likely have been made had the 1952 Act been in force.

Weakest link (the likely saving element): E4 + E7 taken together — the accelerating well is carried on the throttle shaft and its own rotation lifts its inlet port above the float-chamber level, converting a level-equalized reservoir into a temporarily super-elevated head. This is a structural/kinematic interrelationship producing a new mode of operation: the same well is (i) a float-level-tracking reservoir when the throttle is closed and (ii) a head-generating gravity reservoir when the throttle opens, then non-replenishing until the port is resubmerged. I found no reference teaching eccentric mounting of a well on a throttle stem, nor rotation of a well to raise its inlet above its supply level. On the present record, E4/E7 are the limitations on which validity would turn, and they are precisely the limitations the examiner appears to have relied on (the claim is narrow — a single, highly specific, result-laden claim).

Also note the tension the claim imposes: E5 requires the inlet to maintain equality with the float level, while E7 requires the same inlet to be lifted above it on opening. An accused device must satisfy both, so the claim's practical scope is narrow — which cuts against invalidity under § 103 (a narrow claim is easier to distinguish from the art) and also against a broad-infringement theory on the other side of this analysis.

5. What a real § 103 rejection would need

To sustain obviousness, a challenger must produce at least one reference (or a combination) teaching or suggesting:

1. mounting an auxiliary fuel reservoir eccentrically on the throttle valve stem, and
2. rotating that reservoir with the throttle so that its inlet is carried above the float level.

Absent (1)–(2), the obviousness case rests on mere aggregation of old elements — which, under KSR and Graham, is not enough where the claim recites a specific cooperative structural relationship. Useful places to look, which I could not reach:

• Pre-1919 US classes 123/119–127 and 261 (carburetor) full-text; the Smithsonian USNM Bulletin 173 carburetor survey (which is a systematic pre-1920 catalogue and the single best hunting ground — it indexes accelerating cups and auxiliary wells by patent number and date);
• Stromberg Motor Devices Co. v. Zenith Carburetor Co., 254 F. (unverified pagination) and companion carburetor appeals in the 1915–1930 Federal Reporter, which name and discuss the pre-1919 art of record;
• Foreign art: GB, DE, and FR carburetor publications 1905–1918, which the US art of the period frequently followed.

6. Explicit uncertainties

• I could not verify the filing dates of the "Similar Documents" on the Google Patents page; on their stated publication dates none is pre-1919, but a handful (e.g., US 1,776,734, US 1,777,472, US 1,856,736) may have earlier filing dates and should be checked before being treated as unavailable.
• My citations for Crossley GB 24,584 (1893) and GB 8,399 (1910) rest on secondary sources (the Federal Reporter excerpt and a patent-abstract aggregator) rather than the primary specifications.
• The Stromberg v. Zenith citation (volume 254 F., page/year) is unverified.
• The Heldt textbook excerpt is verified as to text but I did not confirm the edition year; if the edition postdates 1919, it is evidence of skill level only, not § 102 art.