US 3422674

I'll run the requested searches before summarizing.

Scope note on the search

I searched for the exact number 3422674 and US3422674 against patent databases and Federal Circuit materials. Findings and limitations:

• The authoritative source retrieved is the Google Patents full-text record for US3422674A (https://patents.google.com/patent/US3422674A/en), which is also the authoritative text supplied in this task. The search returned that record, not a substitute.
• No CAFC 2026 docket activity was found for this patent. Nothing in the search results ties US3422674 (or "3,422,674") to any Federal Circuit appeal, petition, or 2026 litigation. I cannot confirm the absence definitively — my searches did not hit the CAFC docket system directly — so treat "no litigation found" as a search result, not a certified clearance.
• Searches for the bare string surfaced other, unrelated documents with similar numbers, which I am flagging rather than merging: EP3422674A1 (DNS server/geolocation, 2017 priority), JP patent 3422674 (insulating coil/rotating electric machine, filed 1998), and U.S. application 16/364,674 (Schroeter et al., medical avatar patents). None of these is US3422674A and none is related to it.
• I did not obtain a live USPTO PatentCenter assignment-history record or fee/status page; bibliographic facts below come from the patent's own front-page data.

US 3,422,674 — bibliographic summary

Assignee caveat: the patent is not a corporate-assigned patent. It issued to the inventor personally. Whether any assignment was later recorded is something I could not verify from these searches, and the Searches did not return an assignment record. Do not assume a company owner.

Abstract (as printed)

"Apparatus is provided for continuously and simultaneously analyzing a sample of drilling fluid flowing through a mud ditch for the presence of oil content, gas content and electrical resistivity value. The detected amounts in which they are present are simultaneously logged on graphs for visual correlation which move at a rate corresponding with the depths from which the samples are taken."

Plain-language overview of the claims

There is one claim, and it is independent. Written in ordinary terms, it covers a single apparatus with five required elements acting together:

1. An open-ended housing placed in the flowing stream. A box open at both ends sits in the mud ditch so drilling fluid returning from the well flows through it continuously.
2. Gas analyzer + agitator. A motor-driven agitator rotates in the fluid inside the housing and mechanically strips entrained gas out of the mud; the liberated gas is collected and fed to a gas analyzer that continuously detects its presence.
3. Resistivity measuring means — with a specific structure. Not just "a resistivity sensor": the claim requires a tubular member through which at least a portion of the drilling fluid flows continuously, with electrodes carried in that tube to measure resistivity.
4. Fluorescence oil-detection means — with a specific structure. An ultraviolet light source aimed at the fluid plus solar cells that respond to the fluorescence the UV engenders, to detect oil in the fluid.
5. Recording means, coupled to all three detectors, doing three specific things. It must (a) simultaneously record gas content, electrical resistivity, and oil content; (b) provide a side-by-side display for visual correlation; and (c) be moved with the drilling of the well so the recordings correspond to drilling depth.

Practical reach. Because the claim recites the tube-and-electrode resistivity structure, the UV-plus-solar-cell fluorescence structure, the agitator, and the depth-advancing side-by-side recorder as a combination, infringement analysis would turn on practicing that whole combination — the claim is narrow in that each of the three measurement subsystems is tied to a particular implementation, and the depth-correlated simultaneous recorder is itself a claimed element. Notably, the "transparent ruler 37" described in the specification for reading across graphs is not recited in the claim. The specification also states the method is not limited to the specific embodiment, but no method claim was issued.

Prior art cited on the face of the patent

Forward citations (later patents citing it)

US4355997A (hydrogen sulfide in geothermal steam, R.F. Smith Corp., 1982); US4402910A (gas sampling system, Exlog Smith, 1983); FR2556465A1 (NL Industries, 1985, hydrocarbon detection tests); US4546640A (positive air gas detector, 1985); US5181419A (drilling mud sampling, Schlumberger, 1993); US6276190B1 (differential total-gas determination while drilling, Zamfes, 2001); and two Fuji Electric steam-measuring applications/publications (2011, 2016). These are citations, not indications of litigation or validity challenges.

Explicit uncertainties

• No CAFC or district-court record found for this patent, and I did not access the docket system directly enough to certify that none exists.
• No assignment history verified. The patent shows individual (not corporate) ownership, but later recordals are unconfirmed.
• Inventor's city is ambiguous in the printed record: the OCR/print renders it in a way that appears to be "Ojai, Calif." alongside a Bakersfield mailing address. I am not auto-correcting it; treat the residence city as uncertain.
• US Cl. 73–153 and Int. Cl. E21b 49/02 are printed class identifiers reflecting 1969 practice; CPC E21B49/005 is the modern mapping assigned by Google Patents, not something printed on the 1969 document.
• The full text sources contain OCR artifacts (e.g., "fluorescene," "continuosuly," "drillingfluid," ""ice drilling fluid"). These are transcription errors in the scanned text, not the patent's own wording; I have not relied on them for any substantive point.

I'll search for litigation records involving US patent 3,422,674.

Let me refine my searches to target litigation databases specifically.

Let me try a few more targeted searches on litigation-specific databases.

Litigation Search Results — US Patent 3,422,674

Bottom line: I found no evidence of any litigation involving US Patent 3,422,674 ("Continuous well logging apparatus," John D. Schroeter).

What I searched

I ran searches across litigation-focused and general patent sources, including Unified Patents' litigation resources, CourtListener/RECAP, Docket Alarm, Justia, CAFC opinion pages, and general web searches using the patent number in multiple formats ("3422674," "3,422,674," and paired with the title, inventor name, and subject matter). I did not have direct database-query access to PACER; my results are limited to what surfaced through web search.

Result: no matches

None of the results returned any complaint, docket entry, ITC investigation, PTAB proceeding, or CAFC appeal referencing US 3,422,674 (patent number 3,422,674 / 3422674 / 3,422,674) or naming John D. Schroeter as a party.

Every "674" hit in my searches was a different patent, and per your instruction I am not conflating them:

I flag these expressly because auto-correcting or substituting a similar number would produce a false positive, which is the exact error to avoid here.

Corroborating context

Two independent signals support a finding of no known litigation:

1. The Google Patents page for US3422674A contains no litigation/litigation-history section. It lists 3 cited prior-art patents, 7–8 forward citations, and similar documents, but no "Lawsuits" or "Litigation" data (Google Patents would normally populate this for asserted patents).
2. The patent's term would have expired January 21, 1986 (the record shows "Anticipated expiration — 1986-01-21," i.e., the 17-year term from the January 21, 1969 issuance). Any infringement suit would therefore have had to be filed on or before that date. The patent is and has long been in the public domain, which materially reduces the likelihood that a searchable litigation record exists.

Caveats and limitations

• I cannot rule out litigation with certainty. Pre-1986 district court dockets (especially those not digitized into CourtListener/RECAP and not covered by free web sources) are frequently absent from searchable databases. A PACER or a full commercial litigation database (e.g., Docket Navigator, Lex Machina) search would be needed to be definitive.
• I did not find any assignment, reissue, or reexamination record that would signal enforcement activity.
• No litigation, ITC Section 337 investigation, or PTAB/AIA proceeding involving this patent was identified.

If you need a definitive answer

Because this is a 1969 patent with a 1986 expiration, I recommend a targeted search of:

• PACER (all district courts, filings 1969–1986) for the patent number and for "Schroeter" as plaintiff.
• Docket Navigator or Lex Machina (patent module), which index older and non-digitized dockets more completely than free tools.
• USPTO Patent Assignment and Reexamination records to check for any transfer or post-issuance proceeding.

I could not complete these direct-database searches within my available tooling, so I am reporting my conclusion as "no litigation found," not "litigation confirmed to not exist."

Disclaimer: I am not your attorney, and this is not legal advice. This is a factual search summary based on publicly available web results as of the search date; verify against authoritative court records before relying on it.

I'll verify the canonical "no proceedings" signal against public sources before writing.

Let me run a few more targeted checks to be thorough.

Proceedings overview

Total AIA trial proceedings on US 3,422,674: zero. The USPTO Open Data Portal returns no petitions, no institution decisions, no Final Written Decisions, and no terminations — and my independent searches (Google Patents, general web, PTAB/patent-number queries in the form US3422674 and 3,422,674) surfaced no IPR, PGR, or CBM proceeding, no Board decision, and no Federal Circuit appeal. The only third-party documents that reference 3,422,674 are foreign publications citing it as prior art (e.g., BR8402408A, DK254584) — that is citation activity, not a PTAB proceeding. The defensive posture is therefore not "hardened by surviving IPRs" and not "claims canceled" — it is a third thing entirely: the patent expired on 1986-01-21 and is outside the AIA-trial regime in practice, so a demand letter citing it is a red flag on the sender, not a threat to you.

Proceedings overview — required per-proceeding entries

There are no proceedings to enumerate. Rather than invent proceeding numbers (expressly prohibited), here is the structural reason the list is empty, which is itself the substantive answer:

(none) — no petitioner v. John D. Schroeter

• Type: N/A — no IPR, PGR, or CBM petition has ever been filed against this patent.
• Filed: N/A
• Status: No PTAB activity on file. (Google Patents lists the patent's legal status only as "Expired - Lifetime," with an "Anticipated expiration" of 1986-01-21 — that is a patent-term event, not a PTAB status.)
• Judge panel: N/A
• Petition grounds: N/A
• Institution decision: N/A
• Final Written Decision: N/A
• Settlement / termination: N/A
• Appeal: N/A — no FWD to appeal; no CAFC docket located.
• Defensive value: Enormous, but not because of PTAB outcomes. The patent's 17-year term ran from the 1969-01-21 grant date and lapsed 1986-01-21 (consistent with the ODP "anticipated expiration" entry). There is no in-force claim to infringe, so no § 271 infringement theory can be predicated on this patent today, and no PTAB estoppel analysis is even reached.

Why no AIA trial could have been — or can now be — meaningfully filed

This is the analytical core for a defendant. Three independent gates are closed:

1. The statutory window. IPR became available 2012-09-16; PGR and CBM became available 2013-09-16. This patent was filed 1965-11-22 and granted 1969-01-21. By the time any AIA trial was legal, the patent had already been expired for roughly 26 years.
2. PGR is categorically unavailable. Post-grant review under 35 U.S.C. § 321 applies only to patents having at least one claim with an effective filing date on or after 2013-03-16 (AIA § 6(d)). This is a 1965-filing, pre-AIA patent. No PGR is possible, ever.
3. CBM is categorically unavailable. Covered business method review was limited to patents claiming a "financial product or service," and the program sunset 2020-09-16 — no CBM may be instituted after that date. Claim 1 of this patent is a physical mud-ditch logging apparatus (gas analyzer, agitator, resistivity electrodes, UV/solar-cell fluorescence detector, strip-chart recorder). It is not remotely a covered business method.

An IPR of an expired patent is not legally impossible — the Board has allowed such petitions where claim construction still matters (e.g., Sony Corp. v. Yissum Research Development Co., IPR2013-00219), and § 311(a) does not facially exclude expired patents. But the practical return is nil here: the § 286 six-year damages lookback from the patent's 1986-01-21 expiry means any recoverable-infringement window closed in 1992, and a petitioner would be paying IPR fees to invalidate a claim that already has no forward legal effect.

Strategic summary

Claims canceled vs. sustained vs. untested. The patent has one claim (claim 1, apparatus). It is neither canceled by the Board nor sustained by the Board — it was never tested at the PTAB at all. It simply expired. Any infringement demand built on claim 1 fails on the threshold fact of expiry, not on invalidity. For completeness, the only art of record is prosecution-cited: US 2,206,922 (Smith), US 2,704,658 (Gordon), and US 2,740,291 (Brown), all cited by the examiner in 1969 — none was tested in a post-grant forum.

Estoppel landscape — § 315(e)(2). There is no estoppel landscape, because no petition was ever filed. Section 315(e)(2) estoppel attaches only to a petitioner whose IPR reached a Final Written Decision; with zero proceedings, no party is estopped, and, symmetrically, no party has a pre-clusive ruling to rely on. That cuts both ways: you cannot point to a prior FWD invalidating claim 1, but you also do not need to — you have the expiry date. If a would-be plaintiff nevertheless asserts the patent, the correct defenses are not § 102/§ 103 grounds but (i) absence of an enforceable, in-force patent; (ii) 35 U.S.C. § 286's six-year damages bar; and (iii) if the assertor claims to own the patent by assignment, a § 256/§ 261 chain-of-title problem — note the ODP record lists the assignee as the inventor personally ("JOHN D SCHROETER"; original assignee "JOHN D SCHROETER"), with a USPTO Assignment record worth checking on USPTO Assignment if anyone claims standing.

Pattern signals. None of the usual PTAB markers are present: no repeat petitioner, no patent-owner appeal of a Board loss (there is no Board loss), no defensive aggregator such as Unified Patents in the chain. The patent's forward citation set is also thin — a handful of post-grant relatives (US 4,358,997; US 4,402,910; US 5,181,419; US 6,276,190) and foreign filings that cite it as background art. This is a classic "old, narrowly cited, long-expired" patent, not a litigation asset.

Recommended next steps

1. If you received a demand letter citing 3,422,674 — do not treat it as a live assertion. The patent expired 1986-01-21. Confirm the expiry yourself on Google Patents US3422674A (legal status "Expired - Lifetime"; anticipated expiration 1986-01-21) and against the USPTO record via Patent Center and the USPTO Open Data Portal. There is no in-force claim 1 to infringe.
2. Verify there is no continuation, reissue, or child application. The ODP family listing shows only US 509136 → US 3,422,674 (family ID 24025431) with no continuation-in-part or divisional members in the US. If a modern "owner" is asserting this number, ask for the reissue or continuation they actually mean — a 1969 apparatus patent cannot reach current logging tools.
3. Confirm the PTAB negative. Run the patent number through PTAB E2E / PTAB Center and the USPTO PTAB Decisions search yourself; and check CourtListener and the Federal Circuit docket for any appeal. My searches and the ODP ingest both come back empty, but the negative should be documented in your file before you respond to any letter.
4. If the assertion persists, respond on the expiry, not on validity. Quote the ODP entry verbatim: legal status "Expired - Lifetime," anticipated expiration 1986-01-21. A letter demanding royalties on an expired patent is a candidate for a state-law unfair-practice or fee-shifting response; preserve the letter.
5. Do not budget for AIA-trial defenses. There is nothing to file against and no § 315(e)(2) estoppel to exploit. The absence of PTAB activity here is not the "well-asserted patents eventually attract IPRs" signal — it is the much stronger signal that this patent's term ended four decades ago and no institution could revive it.

Confidence note: I have high confidence in the zero-proceedings finding (it is corroborated by both the ODP ingest block and independent searches) and in the 1986-01-21 expiration date. I did not locate any CAFC docket number, because I found no appeal to locate; if an appeal exists it is not indexed in the sources I can reach, and I will not fabricate one.

I'll verify the assignment record before drafting. Let me check the sources.

Inventors

Notes on unusual patterns:

• There is only one inventor, and he is also the sole original assignee (Google Patents lists "Current Assignee: JOHN D SCHROETER"; "Original Assignee: JOHN D SCHROETER"). This is an individually owned patent, not a corporate one — so the "inventors depart the assignee" heuristic cannot be applied. There was no corporate assignee for him to depart.
• No employment agreement or assignment-to-employer is evidenced anywhere in the file. He is listed with a personal street address in Bakersfield, consistent with an independent/sole-proprietor inventor or consultant rather than an employee of a major oilfield-services company (contrast: contemporaneous Schlumberger, Halliburton, or Baroid filings in class 73/153, which almost always name a corporate assignee on the front page).

Original assignee

• Entity on the issued patent: John D. Schroeter (natural person), address on file 3205 Jade Ave., Bakersfield, Calif. 93306.
• Product embodying the claims: Not determinable / no evidence found. A patent owned and prosecuted by an individual in 1965–69 could reflect either a working field prototype or an unconsummated design. The specification describes a mud-ditch skid-mounted unit (open-ended housing 12, gas collection chamber 15, agitator 20, resistivity tube 21 with electrodes 21a, UV source 24 with solar cells 25, three-pen recorder 27) in concrete, buildable terms, but nothing in the record shows it was manufactured or sold.
• Primary line of business: Not applicable — individual, not a company.
• Current status: The patent itself is expired. Google Patents legal events record an anticipated expiration of 1986-01-21 (17 years from the 1969-01-21 issue date) and status "Expired – Lifetime." Any business the inventor may have operated has no bearing on enforceability; the claims have been unenforceable for roughly four decades.

Assignment timeline

No recorded assignments found. I checked the USPTO Assignment Center entry point (https://assignmentcenter.uspto.gov/, mirrored at https://assignment.uspto.gov/patent/index.html) via indexed sources and cross-referenced the Google Patents legal-events and family data for US3422674A. Neither surface shows any pre-issuance assignment to a company, nor any post-issuance conveyance (Assignment, Security Agreement, Merger, Change of Name, License, Release, or Correction). The Google Patents "Family / Applications Claiming Priority" section lists the single application US509136 and nothing else.

Per the stated rule, I am stopping this section here: the Assignment Center has no records for this patent beyond the original individual ownership, and that is itself the finding. The original (and only) owner of record is the inventor, John D. Schroeter.

Two caveats, stated plainly rather than glossed:

• I could not drive the Assignment Center's interactive JavaScript search directly; the US3422674A Assignment-Center result page returns no assignee-change entries through indexed access, and Google Patents' legal-events timeline — which is populated from the same USPTO assignment data — likewise shows no conveyance events, only the filing, grant, and expiration. If a paper-era (pre-1980s) assignment was recorded and never digitized, it would not appear here; that is a records-completeness gap, not evidence of a transfer.
• There is no inventor name match to any modern NPE, holding company, or known high-frequency plaintiff. "Schroeter" appears nowhere in the assignee chains of the seven patents that cite US3422674 (US4355997, US4402910, US4546640, FR2556465, US5181419, US6276190, US20110239649/US9234507), which are attributable to R.F. Smith Corp., Exlog Smith, N.L. Industries, Stone, Schlumberger Technology Corp., Zamfes, and Fuji Electric respectively.

Timeline diagram

timeline
    title Ownership of US 3422674
    1965 : Filed by John D Schroeter individually
    1969 : Patent issued to Schroeter
    1986 : Patent expires with no recorded assignments

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. No assignment to any LLC at all, therefore no "IP / Holdings / Licensing" transferee, no registered-agent address, and no single-purpose entity in the chain. The only named owner is a natural person at a residential street address (3205 Jade Ave., Bakersfield, Calif.).

2. Known asserter in the chain — Not present. No assignee entity exists to compare against the Acacia / Marathon / IV / IPNav / Wi-LAN / Conversant / Vringo / Pendrell / Innovatio / MPHJ / Lumen View / Round Rock / Erich Spangenberg lists. Note also the timing: the patent expired 1986-01-21, roughly a quarter-century before the modern assertion economy (Acacia's and Marathon's assertion programs scale from the mid-2000s; MPHJ from 2012; the Unified Patents and RPX directories cover post-2012 activity). No such asserter could hold an enforceable interest here.

3. Repeat correspondent across the chain — Not present / not applicable. There is no chain. No prosecuting or recording attorney name appears in any assignment record, so there is no correspondent to test for recurrence. (The patent's own attorney of record appears only as illegible OCR in the printed patent — "M apaAZbu' w ATTORNEYS" — and is not a recorded-assignment correspondent.)

4. Cascading transfers — Not present. Zero recorded transfers; the "<24 months through chained LLCs" pattern requires at least two links.

5. Pre-litigation transfer — Not present. No transfer within six months of any suit, because there is no recorded transfer and no recorded litigation naming this patent.

6. Bankruptcy fire-sale — Not present. No corporate assignee ever existed to petition for Chapter 7 or 11, and no sale order, 363 sale, or assignment in bankruptcy appears in the record.

7. Privateering — Not present. Requires an operating-company assignor fronting an NPE; there is no operating-company assignor.

8. Defensive aggregator (anti-NPE) — Not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN; it simply terminated at the inventor and then at the statutory term.

Verdict

Insufficient data (no records, or only the original assignment).

There are no recorded assignments for US 3422674 — only the original individual ownership by inventor John D. Schroeter, per the patent front page and the Google Patents legal-events record, which shows no conveyance events between the 1965-11-22 filing and the 1986-01-21 anticipated expiration. Because the claims expired roughly four decades ago and were never assigned to a corporate or licensing entity, none of the NPE signal tests can be satisfied on the evidence; the "no assignments" outcome here is a genuine finding that the patent stayed with the inventor and lapsed rather than a data gap suggesting a hidden chain. This patent is not an NPE vehicle, and no assertion against it is possible today.

Verification links:

• USPTO Assignment Center (search by patent number 3422674): https://assignmentcenter.uspto.gov/
• USPTO legacy assignment index: https://assignment.uspto.gov/patent/index.html
• Google Patents legal events for US3422674A: https://patents.google.com/patent/US3422674A/en

Prior-Art Analysis — US 342,2674

1. The patent under review (baseline)

Sole claim (Claim 1), element breakdown — an apparatus comprising in combination:

1. An open-ended housing positioned in a stream of drilling fluid flowing from the well;
2. Analyzer means coupled to the housing for continuously detecting gas entrained in the fluid;
3. Agitator means in the housing for continuously expelling gas into the analyzer;
4. Measuring means in the housing for continuously measuring electrical resistivity, including a tubular member through which drilling fluid flows continuously and which incorporates electrodes;
5. Fluorescence indicating means in the housing for detecting oil, including a source of ultraviolet light directed at the fluid and solar cells responsive to the fluorescence;
6. Recording means coupled to all three detectors, simultaneously recording gas content, resistivity and oil content, providing a side-by-side display for visual correlation, said recording means being moved with the drilling of the well to correspond to the depth of drilling.

Note: I could not independently retrieve the full front-pages/specifications of US 2,206,922 and US 2,704,658 through live search within the available steps; the descriptions of those two below are drawn from the citation data in the patent itself plus partial search results and are flagged where confidence is limited. US 2,740,291 was retrieved and is quoted directly.

2. Cited references on the face of US 3,422,674

The patent lists exactly three references under "References Cited" (all examiner citations, all classified 73‑153):

The "X" annotation indicates the examiner regarded these as anticipating or particularly material to novelty — a strong signal that they were relied upon in a § 102 (or, in the alternative, a § 103) rejection during prosecution.

Reference A — US 2,206,922

• Full citation: US 2,206,922, "Means and method for locating oil bearing sands," 73‑153, issued July 1940. The printed patent front page names the inventor as Smith. (Indexed data on Google Patents associates the number US 2,206,922 A with an assignee/inventor Starr Thayer, priority 1938‑08‑08, publication 1940‑07‑09 — a discrepancy I report literally rather than resolve.)
• Dates: filed 1938, published/issued July 1940.
• Brief description: Concerned with locating oil-bearing sands during drilling. It falls in the same 73‑153 art as the patent (investigating drilling fluid / oil detection in well operation). It was cited with an X designation, indicating materiality to the novelty of the claimed oil-detection subject matter. Related contemporaneous art in this family (e.g., US 2,213,138, "Method and apparatus for detecting oil in well drilling," issued Aug. 27, 1940) teaches subjecting the returning drilling mud to a fluorescence-exciting ray to render otherwise invisible crude oil visible by fluorescence — the same physical principle claimed here. Confidence in the specific internal disclosure of 2,206,922 is moderate; the fluorescence-of-mud principle is well documented in this 1940 art cluster.
• Potentially anticipated claim(s): Claim 1 (element 5) — the fluorescence-based oil detection. Under § 102 this reference is most relevant to the oil/fluorescence element; it does not appear to disclose the full multi-analyzer combination plus depth-correlated simultaneous recorder, so it is unlikely standing alone to anticipate the entire claim. It is the prototypical § 103 base reference against element 5.

Reference B — US 2,704,658

• Full citation: US 2,704,658, titled (per the indexed record) "Mud agitator," 73‑153, issued March 1955 (Gordon).
• Dates: issued 3/1955.
• Brief description: A mud agitator — i.e., apparatus for agitating drilling fluid ("mud"). This maps directly onto the claimed agitator means in said housing for continuously expelling gas from said fluid (element 3). Its being cited with an X in class 73‑153 shows the examiner treated mud-agitating apparatus as anticipating/rendering obvious that sub-combination.
• Potentially anticipated claim(s): Claim 1 (element 3) — the agitator means for expelling gas from the drilling fluid. Alone it does not reach the gas-analyzer + recorder + resistivity + fluorescence combination, so § 102 anticipation of the whole claim is doubtful; it is the natural § 103 reference for the gas-expulsion/agitator element.

Reference C — US 2,740,291

• Full citation: US 2,740,291, "Device for obtaining samples of formation cuttings entrained in drilling fluids," Joel B. Brown, assignor to Addeco, Inc. (Shreveport, La.), filed Oct. 8, 1951, Ser. No. 250,363, patented Apr. 3, 1956, 9 claims, Cl. 73‑153. Source: https://patents.google.com/patent/[US2740291A](/patent/US2740291A)/en

• Dates: filed 10/08/1951; issued 04/03/1956.

• Brief description (quoted from the specification, high confidence): This reference describes a recorder/sampler for well drilling and states its desiderata in terms remarkably close to the patent at issue:

  "it is desirable to log or graphically record the resistivity, radio-activity, gas content and hardness of the earth formations traversed during the drilling operations in such manner that all characteristics can be simultaneously recorded and simultaneously compared to determine the type of formation found at any level… It is also desirable to obtain identified samples… The recorder and sampling device should operate in synchronism in order that the samples from a given level of the well may be compared with the recorded characteristics of the earth formation at the given level. The recorder and sampling device should be automatic in operation…"

  It further discloses driving the sampler/recorder in accordance with the descent of the drill (via a mechanical transmission from the Kelley block) so that samples and recordings are obtained from uniformly spaced levels — i.e., depth-correlated logging.

• Potentially anticipated claim(s): Claim 1 (element 6) — the recording means that simultaneously records multiple logged characteristics and is moved with the drilling of the well to correspond to the depth of drilling. Brown's synchronous, depth-correlated, simultaneous multi-channel recording disclosure is the closest prior art to the recording/correlation element of Claim 1 and is a strong § 102/§ 103 reference for that element. Brown does not disclose the claimed UV/solar-cell fluorescence oil detector, the resistivity electrode tube, or the mud-ditch housing, so it cannot alone anticipate the entire combination claim.

3. Overall § 102 / § 103 assessment

• Only one claim exists — Claim 1 — a single combination apparatus claim. Anticipation under 35 U.S.C. § 102 requires a single reference disclosing every element arranged as claimed.
• On the record, no single cited reference appears to disclose all six elements (open-ended mud-ditch housing + gas analyzer + agitator + electrode-tube resistivity + UV/solar-cell fluorescence + simultaneous depth-correlated side-by-side recorder). Each reference maps to a different element:
  • 2,206,922 → oil/fluorescence detection element (element 5);
  • 2,704,658 → agitator/gas-expulsion element (element 3);
  • 2,740,291 → simultaneous, depth-synchronized multi-characteristic recording element (element 6).
• Accordingly, the more likely basis on which these references were applied is a § 103 obviousness combination (mud agitator + oil-fluorescence detection + synchronous multi-channel recorder), with the X citations being the primary references. If any individual § 102 rejection was made, it would have had to be against a sub-combination or against a broader species of one element — not the full claim as written.
• The distinguishing/novel aspects most likely to have survived are the integration of all three analyses in a single open-ended housing in the mud ditch, and the solar-cell-based fluorescence detector ("sensitive to a wide spectrum of radiant energy as compared to present photo-detectors" — specification), plus the transparent-ruler side-by-side depth-correlated readout (element 6's "side-by-side display for visual correlation").

4. Downstream citations (for context, not prior art against 3,422,674)

The patent's "Cited By" list (third-party later art) — useful only as evidence of the field's development, not as § 102 art against this patent (they post-date the 11/22/1965 priority):

• US 4,355,997 (1982), US 4,402,910 (1983), US 4,546,640 (1985), FR 2,556,465 A1 (1985), US 5,181,419 (1993, Schlumberger), US 6,276,190 B1 (2001, Zamfes), US 2011/0239649 A1 / US 9,234,507 B2 (Fuji Electric, 2011/2016).

Caveats

• I was unable to fetch the full text of US 2,206,922 and US 2,704,658 in the available search steps; their element-level descriptions above are inferred from the patent's own citation data, the 73‑153 classification, the "X" materiality codes, and closely related contemporaneous art. Treat those two element mappings as probable, not confirmed.
• The inventor/assignee data for US 2,206,922 conflicts between the printed patent ("Smith") and Google Patents' indexed record ("Starr Thayer"); both are reported literally, per the no-auto-correction rule.
• No legal conclusion as to validity or infringement is intended; the above is a technical prior-art mapping keyed to the single claim of US 3,422,674.

I'll ground this analysis by verifying what each cited reference actually discloses before building the §103 combinations.

Let me verify the specific disclosures of the two remaining examiner-cited references.

1. Scope of the claim and the legal framework

Claim 1 (the sole claim) of US 3,422,674 recites, at a high level of generality, a combination of seven elements:

Every element is recited in means-plus-function / functional language, and each is expressed as a separate instrumentality performing its own independent function (detect gas; agitate; measure resistivity; detect fluorescence; record three traces). Under Graham v. John Deere and KSR v. Teleflex, the question is whether the claimed combination as a whole would have been obvious, with the level of ordinary skill set by the fact that surface mud logging was a mature rotary-drilling discipline by 1965.

2. Which references are actually available as § 103 prior art

The priority date is 22 Nov 1965. Critically, only three of the references on the page are prior art at all:

Note also a literal-reading discrepancy I am not correcting: the patent's own "References Cited" column prints the 1940 reference as "Smith," while the Google Patents citation table lists US 2,206,922 with "Starr Thayer" and the title "Means and method for locating oil bearing sands." I flag this rather than reconcile it.

3. Element-by-element mapping to the cited prior art

US 2,740,291 (Brown, 1956) — the "hub" reference. Verified from the specification text: it teaches the express desirability of

"log[ging] or graph[ing] the resistivity, radio-activity, gas content and hardness … in such manner that all characteristics can be simultaneously recorded and simultaneously compared to determine the type of formation found at any level,"

and that the recorder "should operate in synchronism in order that the samples from a given level of the well may be compared with the recorded characteristics … at the given level," with the recorder and sampling device "connected to the Kelley block … and driven in accordance with the descent of the drill." That maps almost verbatim onto claim elements (f) and (g), and it is far more than a mere "suggestion" — it is an affirmative statement of the objective the claim sets out to achieve.

US 2,206,922 (1940). I was unable to retrieve the full text within my search budget, so I rely on its Google Patents listing (title/date) and on the patentee's own citation of it as the oil-in-mud detection art. I will not fabricate its disclosure. What I can verify is that the same field and the same technique were notoriously well known by 1940: US 2,288,942 (Doan/Phillips) expressly discloses a portable, light-excluding housing through which a continuous stream of drilling fluid from the well is passed, with a source of ultraviolet radiation illuminating the fluid so that "the fluorescence which results when ultraviolet rays impinge upon any oil … may be observed"; and US 2,213,138 describes both the UV "dark box" examination and the option of running a continuous sample of the mud stream through the inspection apparatus. US 2,361,261 goes further and reads the fluorescence with a photoelectric cell and galvanometer. So element (e) minus the "solar cell" species was old and well documented.

US 2,704,658 (Gordon, 1955, "Mud agitator"). I could not retrieve the body of this reference either; on the face of the title it is the structural counterpart of element (c) — a rotating agitator operating on the drilling-mud stream. The gas-liberation function of agitation (mechanical breaking-out of entrained/"cut" gas from mud, followed by collection and analysis) is the standard, well-understood mud-logging operation, which is why the examiner cited it.

4. The combinations that render claim 1 obvious

Combination A (strongest): US 2,740,291 + US 2,206,922 + US 2,704,658

• US 2,740,291 supplies (a) the mud conduit/flow path, (f) the simultaneous multi-tract recorder with side-by-side display for comparison, and (g) the recorder driven in synchronism with drill descent (Kelley block). It also supplies the express motivation: it states that resistivity and gas content and other formation-indicative measurements should be recorded simultaneously and compared at each level of the well, automatically.
• US 2,206,922 (reinforced by the contemporaneous US 2,288,942 / US 2,213,138 / US 2,361,261) supplies (e) the UV-excited fluorescence detection of oil in drilling fluid flowing from the well.
• US 2,704,658 supplies (c) the agitator, whose recognized function in the mud-handling art is to liberate entrained gas from the mud so it can be collected and analyzed, satisfying (b) when coupled to a gas analyzer of the type US 2,740,291 already contemplates.

Motivation to combine, stated in the references themselves: US 2,740,291 supplies the why (simultaneous recording and comparison of resistivity and gas content, correlated to depth). All three references are in the same field of endeavor (surface handling/analysis of drilling fluid at a rotary rig), so they are analogous art and reasonably pertinent to the problem the patentee addressed. Under KSR, "if a technique has been used to improve one device, and a person of ordinary skill … would recognize that it would improve similar devices in the same way, using the technique is obvious."

Predictable result: the combination is a mere aggregation — each instrumentality performs exactly its own known function and yields its own known result, the only "new" feature being their co-location on one recorder. Aggregation of known instrumentalities without a new cooperative relationship is not patentable subject matter under § 103. That the patentee himself concedes in the Background that the viewing-box UV test, the gas tests, and the like were all individually known strengthens the "obvious to try"/predictable-result position.

Combination B: US 2,740,291 as primary + oil-fluorescence art + known in-line mud resistivity measurement

Even if US 2,206,922 is read narrowly as limited to oil-bearing-sand location, US 2,740,291 alone teaches that resistivity and gas content should be simultaneously recorded against depth. Adding a third known mud-logging channel — the electrical resistivity of the returning mud, measured by electrodes in contact with the flowing fluid — is, at most, the selection of a known measurement for a known slot in a known recorder, i.e., a predictable use of a known technique. The specific "tubular member through which a portion of the drilling fluid flows continuously, said tubular member incorporating electrodes" is a design choice for keeping the electrodes at a fixed spacing in a variable-level ditch, and the art of measuring the resistivity of a flowing fluid column between fixed electrodes is fundamental.

Where the § 103 case is weakest — be candid

1. "Solar cells" as the fluorescence detector (element (e)). None of the three cited references discloses a photovoltaic detector, and none was cited for it. The patentee touts this as the inventive improvement ("solar cells are sensitive to a wide spectrum of radiant energy as compared to present photo-detectors"). A rigorous obviousness challenge needs a secondary reference or evidence that substituting a photovoltaic (solar) cell for the photoelectric cell of, e.g., US 2,361,261 was a known design choice. Given the broad spectral response of photovoltaic cells was itself the known property being exploited, this is likely an obvious substitution of one known light-responsive element for another — but it is the element most in need of additional art.
2. The flow-through electrode tube of element (d). Not shown in the three cited references; in-line conductivity cells for fluids were, however, a crowded art by 1965.
3. "Continuously" in elements (b)–(d). US 2,740,291 samples intermittently (buckets), so the "continuously" limitations must be met from the continuous-flow teachings of the oil-detection art (US 2,288,942: "continuously examining the drilling fluid when it emerges from the well bore"; US 2,213,138: continuous flow-through option).

5. Secondary considerations

There is nothing of record on the face of the patent supporting non-obviousness: no evidence of unexpected results beyond the asserted broad-spectrum sensitivity of solar cells (which is an inherent property of the cell, not an unexpected result of the combination), no evidence of commercial success, no evidence that others tried and failed, and no evidence of a long-felt but unmet need that the three cited references somehow taught away from. The objective need the patent identifies — simultaneous, depth-correlated readings — is the very need US 2,740,291 already articulates.

6. Bottom line

• Claim 1 is not anticipated by any single cited reference.
• Claim 1 is, however, substantially vulnerable under § 103 over US 2,740,291 in view of US 2,206,922 and US 2,704,658, with US 2,740,291 doing the heavy lifting because it expressly discloses and motivates simultaneous recording of resistivity and gas content synchronized to drill depth (elements (f) and (g)) — the two elements that give the claim its asserted point of novelty.
• The residual weaknesses in the prima facie case are the recitations of "solar cells" and the tubular electrode resistivity cell, which would require supplementary art (e.g., 1950s–60s photovoltaic-detector art and in-line fluid conductivity-cell art) to close cleanly.
• The "Cited By" references on the page (US 4,355,997; US 4,402,910; US 4,546,640; FR 2,556,465; US 5,181,419; US 6,276,190) are inadmissible as prior art against this 1965 filing and cannot support an obviousness rejection; they are relevant only as evidence that the field continued to develop in the direction the patentee described.
• No § 103 rejection appears of record: the patent issued with three references cited and the single claim allowed.

Verification limitations: I confirmed the full text of US 2,740,291 and the corroborating fluorescence art (US 2,288,942, US 2,213,138, US 2,361,261) directly. I could not retrieve the bodies of US 2,206,922 or US 2,704,658 within my search budget, so my treatment of those two rests on their titles/dates as listed and on the state of the analogous art; any conclusion that turns on their precise disclosures should be re-checked against the full documents before being relied upon.