US 1538730

I'll check live sources for this specific patent number and any 2026 CAFC docket activity before summarizing.

US 1,538,730 — Record Verification and Summary

Search note up front: I searched for US 1,538,730 specifically (both the granted number and the application's serial No. 730,783) and for any Court of Appeals for the Federal Circuit 2026 docket activity naming this patent or its inventors. I found no 2026 CAFC docket entry, no litigation, and no post-issuance administrative proceeding (IPR/PGR/reissue) involving this patent. I could not query the CAFC docket system directly, so this is a negative finding from available search results rather than an exhaustive registry check. Given the record below, that result is expected: the patent issued in 1925 and expired in 1942, roughly 84 years before any 2026 appeal could exist. If you have a specific CAFC appeal number you believe maps to 1,538,730, send it and I will pull the docket — but nothing in the live sources supports a 2026 appellate connection.

Bibliographic data (from the granted patent front page and Google Patents)

Abstract

There is no formal abstract. This patent predates the 1947+ practice of a printed claim-abstract; the printed document goes from the specification directly to "What we claim…". Google Patents therefore shows no abstract field. For convenience, the gist is:

A drop-forming device in which pins are inserted through apertures in the perforated bottom of a liquid container. Each pin has a shank narrower than the aperture, leaving an annular flow passage, and a blunt (flat, right-angle-cut) lower end. Liquid flows from the container through the annular passage, down the pin shank, and forms a drop of predetermined size at the blunt tip, which then detaches and drips free.

Plain-language overview of the independent claims

There are three claims, all independent (no dependent claims). All three use the transitional phrase "consisting of," which in modern claim construction (per Norian Corp. v. Stryker, Fed. Cir.) is a closed-ended transition — a notable drafting quirk for a 1925 mechanical claim and a real limiting consideration if the claim were ever construed today.

Claim 1 — A drop-forming device comprising (i) a liquid container with an opening in its bottom, and (ii) a pin passing through that opening, the pin diameter being predetermined so liquid passes through at a predetermined rate, where the pin's lower end is cut off at substantially a right angle to present a drop-forming surface of predetermined area. In plain terms: a container, a hole, and a blunt-cut pin in the hole whose flat tip controls drop size.

Claim 2 — The same device, but narrowed to a cylindrical pin passing through the opening of predetermined diameter at a predetermined flow rate, with the lower end cut to form a flat horizontal drop-forming surface. Claim 2 is essentially Claim 1 with (a) the pin shape limited to cylindrical and (b) the cut surface limited to flat and horizontal.

Claim 3 — A drop-forming device comprising a container with a pair of openings in its bottom, and a U-shaped member whose legs project downwardly through those openings, the legs' diameter leaving a predetermined annular space. Claim 3 reads on the wire-forming embodiment described in the specification, where a piece of wire is bent into a U so that its two legs act as two pins, held centered in two adjacent apertures — the loop (bridge piece) setting the pin spacing and centering them.

Note the claim/spec correspondence: the specification's "bridge piece d" and the U-shaped wire are the antecedent basis for Claim 3's U-shaped member; Figs. 1–2 show a vessel a, bottom apertures b, pins c, and bridge piece d.

Legal status and downstream citation interest

• Expired — 17-year term ran from May 19, 1925, to May 19, 1942. The patent is long since dedicated to the public; it cannot be enforced, so there is no live infringement or validity controversy to reach the CAFC.
• Cited by roughly 15–17 later US patents. The most contemporarily interesting lineage is the Dippin' Dots / cryogenic pellet-forming family — e.g., US 5,664,422 (Jones, 1997), US 6,000,229 and US 6,223,542 (Dippin' Dots, 1999/2001), US 7,464,564 (2008), US 7,316,122 (2008) — which cite this 1925 patent in the context of converting liquid feed into discrete frozen beads. Also cited by US 2,923,148 (Iowa State College Research Foundation, 1960) and US 3,242,237 (Sun Oil Co., 1966).
• Related family/companion art by the same four inventors:
  • US 1,534,729 — "Process for the Manufacture of Colloidal Substances in the Form of Small Balls or Grains," filed March 13, 1924 (Ser. No. 699,127), issued April 21, 1925. Same inventive entity, one month earlier — this is the process counterpart to the 1,538,730 apparatus.
  • A German counterpart appears in the literature as Patent No. 434443 (A.-G. für chemische Produkte vorm. H. Scheidemandel, A. Obersohn, W. Wachtel, Berlin, and Dr. D. Sakom, Wiesbaden), dated 16 March 1923.
  • A Polish registration is indexed as "Przyrząd do wytwarzania równomiernych kropel" (apparatus for producing uniform drops), filed 4 June 1924, granted 3 February 1926, naming the same four inventors plus the A.-G. entity.

Explicit uncertainties and ID-handling notes

1. Inventor name variants. The OCR of the granted PDF renders the second inventor as "WILHELM WAGHTEL" (and elsewhere "Haehlel"), while the Google Patents bibliographic metadata and other sources give "Wilhelm Wachtel." I have not auto-corrected the patent number or any identifier; the spelling variance is in the source documents themselves. The name is most likely Wachtel, but I flag the OCR variants rather than silently normalizing them.
2. Assignee discrepancy. Google Patents reports "Individual," but the German-language counterpart record (German Patent 434443) names a corporate applicant, Aktiengesellschaft für chemische Produkte vormals H. Scheidemandel, alongside the individual inventors. That is a different national document, not US 1,538,730, so it does not establish a US assignment. I do not have authoritative US assignment-record data (no USPTO Assignment abstract of title was retrieved), so the US chain of title is unknown to me.
3. No abstract exists — stated above; anyone expecting a formal abstract field for a 1925 patent will not find one.
4. Examples with lost numerals. The specification's Examples I–II read as "about 40%" glue "at a temperature of ___ C." and a "20% solution of gelatine at 60° C." — the glue temperature numeral is corrupted in the OCR and I will not guess it.
5. "Rotary filters" use (Example IV) — the specification contemplates uniform water distribution onto a filtering layer, i.e., a non-pelletizing application of the same hardware.
6. No evidence of 2026 CAFC activity, as noted at the top. I cannot rule out a docket I could not see, but nothing supports it, and the patent's 1942 expiration makes live appellate litigation implausible.

Sources: granted patent text and bibliographic data at https://patents.google.com/patent/US1538730/en; printed PDF https://patentimages.storage.googleapis.com/d6/33/59/844ce59873b858/US1538730.pdf; companion patent US 1,534,729 at https://patents.google.com/patent/US1534729; citation/citing-patent data via https://patents.google.com/patent/[US6223542B1](/patent/US6223542B1)/en.

I'll search for litigation involving US patent 1538730 across the sources you specified.

Let me run additional targeted searches to confirm.

Summary Finding

No litigation involving U.S. Patent No. 1,538,730 is known. I found no district court case, ITC investigation, CAFC appeal, PTAB proceeding (IPR/PGR/CBM), or other adversarial proceeding in which US 1,538,730 was asserted, challenged, or otherwise at issue.

Patent Identified (for disambiguation)

Because the bare number "1538730" matches a large number of unrelated documents, I want to be explicit about which patent I searched for and confirm I did not dilute the query with similar numbers:

• US 1,538,730 A — "Device for converting liquids into uniform drops"
• Inventors: Albert Obersohn (Berlin-Charlottenburg), Wilhelm Wachtel, Daniel Sakom, Paul Askenasy
• Application No. US 730,783; filed 1924-08-07; granted/publication 1925-05-19
• Assignee: Individual (unassigned)
• Claims: 3
• CPC: C09H9/04 (Drying of glue or gelatine in the form of granules, e.g. beads)
• Legal status per source: Expired – Lifetime, with anticipated expiration recorded as 1942-05-19
• Source: https://patents.google.com/patent/US1538730/en

Searches Performed and What They Returned

I ran multiple targeted queries and then filtered strictly for U.S. Patent 1,538,730. Results:

1. "US patent 1538730 litigation" / "1538730 patent infringement lawsuit" — No litigation. Hits were false positives on the bare number: CN 1538730 A (Broadband Public Telephone System) and EP 1538730 A4 (Drive Device, Aisin), plus KR 10-1538730 (a Korean concrete box girder patent) and CN 101538730. None are US 1,538,730.
2. "1,538,730" / "US1538730" lawsuit / defendant / court — No litigation. Hits were the Google Patents page itself and prior-art citations.
3. Unified Patents portal queries — The portal indexed the patent only as a document record / prior-art citation, not as a litigation or PTAB case entry. No case list entry.
4. Case-law and docket-adjacent results — The "730 patent" hits returned (e.g., Whirlpool's 6,971,730; Proxense's 8,352,730; design patent USD1,030,730) are different patents entirely and were excluded.

Evidence of Use as Prior Art (not litigation)

US 1,538,730 does appear in the patent record as cited prior art, which is not litigation but is worth noting for context — it shows the reference remains part of the art-of-record in later drying/droplet-forming technology:

• Cited in US 6,223,542 B1 — "Cryogenic processor for liquid feed preparation of a free-flowing frozen product…" (Dippin' Dots, Inc.), listed as: US1538730A | 1924-08-07 | 1925-05-19 | Obersohn Albert | Device for converting liquids into uniform drops (https://patents.google.com/patent/[US6223542B1](/patent/US6223542B1)/en)
• Cited in US 7,316,122 — "Tray for producing particulate food products," listed among U.S. Patent Documents as 1538730 | May 1925 | Obersohn et al. (https://patents.justia.com/patent/[7316122](/patent/7316122))
• Cited in a later Headwater/Raleigh patent family (e.g., US 9,204,374 / related applications) — note the citation there reads "CN 1538730 A 10/2004," which is a different document; I flag this so it is not mistaken for a US citation.

Confidence and Limitations (stated explicitly)

• High confidence that no litigation is recorded in the accessible sources. The patent issued in 1925 and expired on its original 17-year term in 1942, which alone makes modern assertion impossible and makes historical enforcement highly unlikely.
• Limitations I must flag:
  • I do not have authenticated, live access to PACER, CourtListener/RECAP, Docket Alarm, Unified Patents Portal litigation caselists, or Westlaw/LexisNexis. My queries surface indexed/public web content; these databases are paywalled or not fully crawlable. A conclusively exhaustive negative would require direct database queries.
  • Pre-1940s federal litigation coverage is incomplete in every public database. A 1920s–1940s infringement suit, if one existed, could simply be unindexed. I cannot affirmatively rule that out with certainty, only state that nothing appears in the sources I could reach.
  • Some fragments of the patent text returned by the source are OCR-corrupted (e.g., truncated claim language, garbled inventor names), so any legal analysis built on the literal text of claims 1–3 should be re-verified against the original PDF of US 1,538,730.

Bottom line: Based on searches of the patent-litigation sources you identified, there is no known litigation involving US Patent 1,538,730 — the record shows the patent only as a prior-art citation in later patents. I recommend confirming with a direct PACER/Docket Alarm query if a definitive negative is required, given historical coverage gaps.

Proceedings overview

Zero AIA trial proceedings on file for US 1,538,730. The canonical count from the USPTO Open Data Portal block is 0 — no IPRs, no PGRs, no CBMs — so the breakdown is 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials, and the defensive posture is not "hardened by surviving IPRs" but something more fundamental: the patent expired on 1942-05-19, roughly 70 years before the first AIA trial was ever filed. Any demand letter citing claims 1–3 of this patent is not a licensing opportunity; it is either a records error, a confusion with a different patent number, or outright fraud. The live significance of US 1,538,730 today is as prior art, not as an asserted patent.

Verified search of USPTO PTAB materials and public dockets surfaced no IPR/PGR/CBM petition naming US 1,538,730.

No proceedings to report

Because the structured source lists no proceedings, there is no proceeding number, petitioner, panel, ground, institution decision, FWD, settlement, or appeal to describe for this patent. The section template above is deliberately reported as empty rather than populated with inference. Per the operating rules, I will not invent proceeding numbers, and I found none to report.

Two categories of near-miss search hits are not this patent and should not be confused with it:

Strategic summary

Claim status. US 1,538,730 issued 1925-05-19 with three claims: claim 1 (container with a bottom opening plus a pin of predetermined diameter cut off at substantially a right angle to present a drop-forming surface of predetermined area), claim 2 (same, with a cylindrical pin cut to form a flat horizontal drop-forming surface), and claim 3 (container with a pair of bottom openings and a U-shaped member whose legs project downwardly to leave a predetermined annular space). Google Patents records the anticipated expiration as 1942-05-19 (17 years from grant, no extensions of record) and the status as "Expired - Lifetime." Consequently all of claims 1–3 are expired and unenforceable — not "canceled by IPR," not "sustained," simply lapsed. There is nothing left to infringe and no live claim for any tribunal to cancel or sustain.

Estoppel landscape. § 315(e)(2) estoppel is inapplicable: it only attaches to a petitioner that obtained an institution decision, and no petition was ever instituted or even filed. There is likewise no IPR/PGR estoppel, no claim-construction record, and no FWD findings to leverage. Practically, a defendant's freedom here does not come from IPR estoppel but from the expiration of the patent right itself plus, if the patent were ever somehow asserted, an affirmative unenforceability/laches/expiration defense and the fact that a 1924–1925 disclosure is quintessential § 102(b) prior art against anything filed after May 1925.

Pattern signals. None of the usual patterns exist: no repeat petitioner, no patent-owner PTAB appeal practice, no defensive aggregator (Unified Patents or similar) involvement. The absence of PTAB activity is emphatically not the usual "well-asserted patents eventually attract IPRs" signal — the reason there are no IPRs is that the patent's term ended in 1942, decades before the AIA created IPR/CBM/PGR on 2012-09-16. Note also that the Google Patents "Cited By" list shows this reference being cited by the Dippin' Dots cryogenic-drop patents (e.g., US 5,664,422; US 6,000,229; US 6,223,542; US 7,316,122) — i.e., its modern role is as the seminal prior art in drip-formation technology, which is exactly how it should be treated.

Recommended next steps

• If you have received a demand citing US 1,538,730: do not treat it as a merits question. The patent expired 1942-05-19 and claims 1–3 are unenforceable as a matter of law. Confirm the number against USPTO PatentCenter and Google Patents US1538730A, then push back in writing. If the assertion is being made in litigation, an expiration-based dispositive motion plus a fee/sanctions review of the demand is the appropriate escalation.
• If you are trying to invalidate a modern patent (e.g., a Dippin' Dots-style cryogenic dropper patent) using this reference: US 1,538,730 is available as printed publication prior art with a 1925-05-19 publication date and a 1924-08-07 filing date, and it is the type of art that has historically been cited in that space. Verify per-claim application of the pin-in-aperture architecture against the modern claims before relying on it.
• If you are an examiner or analyst verifying citation chains: the PTAB E2E system (e2e.uspto.gov) and the PTAB decisions page will both return no AIA trial documents for this patent number; the PTACTS hits under the "153..." string belong to unrelated modern patents, as catalogued above.
• Escalation / watch items: there are no pending trial-stage milestones to monitor — no institution deadline, no oral hearing, no statutory one-year FWD due date — because no trial exists. If counsel believes otherwise, the burden is on them to produce a proceeding number and a PTACTS link; absent that, the assertion is unsupported.

Confidence and limits: I have high confidence in the "no PTAB activity" conclusion, corroborated by the ODP block and by targeted searching of PTAB/PTACTS materials, and high confidence in the expiration analysis (1924-08-07 filed, 1925-05-19 granted, 1942-05-19 anticipated expiration). I did not locate any pre-AIA interference, reissue, or reexamination record for this patent, and I make no claim one way or the other about such historical proceedings beyond what the structured data shows — the ODP block records none.

I'll verify the assignment record before writing anything.

Two useful leads surfaced — a German co-applicant and possible pre-1955 paper records. Let me check both.

Inventors

Four joint inventors, all resident in Germany at filing. The US application (Ser. No. 730,783, filed 1924-08-07) names no assignee; the inventors appear on the face of the patent as the owners:

Employer at filing (determinable for only part of the group, and from foreign records rather than from the US file): The parallel German, Hungarian and Polish records for this same invention name the applicants as the individuals together with Aktiengesellschaft für chemische Produkte vormals H. Scheidemandel, Berlin. Dr. Hermann Stadlinger, a director of that company, described the commercialization of the invention — "Leimperlen" and "Gelatineperlen" (glue and gelatine pearls) — in a June 1924 lecture to the Verein Deutscher Chemiker. The strongest single documentary link is a later US case: US 1,951,260 (filed 1931) records "Daniel Sakom, Wiesbaden, Germany, assignor to firm: Aktiengesellschaft für Chemische Produkte vormals H. Scheidemandel, Berlin, Germany" — confirming Sakom's ongoing relationship with the Scheidemandel company. Askenasy, based in Karlsruhe, is identified only as a professor and is the least likely to have been a Scheidemandel employee.

Unusual-pattern check: The signal you asked me to watch for — all inventors departing the original assignee within 12 months of filing, ahead of a fire-sale — is not present and not assessable here, because there was no US assignee from which anyone could depart. The three German-resident industrial inventors and one academic inventor simply filed in their own names in the US while the Berlin company appeared as co-applicant on the foreign counterparts. No 1924–25 departure pattern exists in the record.

Original assignee

There is none. The patent issued on 1925-05-19 to the four individuals. Google Patents' bibliographic record lists both "Original Assignee" and "Current Assignee" as Individual, and the legal-events record contains only four entries — application filed (1924-08-07), priority to US 730,783, application granted (1925-05-19), anticipated expiration (1942-05-19). No conveyance to a company was ever recorded against the US patent.

The de facto commercial backer was not the patent owner. The technology was developed for and commercialized by Aktiengesellschaft für chemische Produkte vormals H. Scheidemandel, Berlin NW 7, Dorotheenstrasse 35 — a manufacturer of animal glues, gelatine, feed and fertilizers, founded 1895-11-18 in Landshut, relocated to Berlin in 1904. It shipped an actual product embodying the claims: pearl-form glue and gelatine produced by dripping glue/gelatine liquor through apertures fitted with the pins claimed here (the same apparatus family is covered by the German counterpart DRP 434,443, filed 1923-03-16, and by sibling US 1,534,729, "Process for the manufacture of colloidal substances in the form of small balls or grains," filed 1924-03-13 by the same four inventors).

Current status of that sponsor: no longer an independent operating company. It merged in 1937 with Schneidemandel Motorrad-Werke AG (the German National Library records the successor as "Scheidemandel-Motard-Werke, Berlin"), was renamed Schneidemandel AG from 1970, moved to Wiesbaden (1980) and Eberbach in Baden (1987), and was integrated into the Sotess-Gruppe in 1999 — a corporate reorganisation, not a bankruptcy sale of the kind in your signal #6.

Patent status: expired at the end of its term on 1942-05-19 (17 years from grant under the law then in force). It has been in the public domain for over 80 years.

Assignment timeline

There are no recorded assignments for US 1,538,730, and none are retrievable from the source you specified.

This is a structural limitation of the database, not merely an absence of activity, and it is worth stating precisely:

• USPTO Assignment Center / Assignment Search contains no reel/frame records for this patent. The electronic index is searchable by patent number and returns nothing for 1,538,730.
• Why: per TMEP § 503.08, US patent and trademark assignment documents recorded before 1955 were entered in bound volumes and cited as "liber and page," not reel/frame; microfilm reel/frame indexing began in 1955. MPEP § 301.01 likewise directs pre-May 1, 1957 patent assignment copy requests to NARA rather than the USPTO (pre-1955 trademark records were transferred to NARA in 1990, and pre-1957 patent records are held there too). This patent was filed in 1924 and expired in 1942 — every conceivable conveyance is pre-1955 and therefore, at best, in NARA's bound volumes and not in the Assignment Center index I was asked to search.
• Consequently no correspondent of record can be identified — there is no cover sheet, no recording attorney, and no reel/frame. Signal #3 (repeat correspondent) is untestable by construction, not merely unproven.

Because the Assignment Center holds no records for this patent, I am stopping here per the instruction you gave, rather than generating an Assignment-timeline diagram, an NPE-signal table, and a verdict that would rest entirely on absent data. For completeness on the one rubric item that is still answerable: the verdict category that applies is Insufficient data — no records exist beyond the original grant to four individual inventors.

Verification: search patent number 1538730 at https://assignmentcenter.uspto.gov/ or https://assignment.uspto.gov/patent/index.html (both return no records for this number); bibliographic and legal-events confirmation at https://patents.google.com/patent/US1538730/en. For any pre-1955 paper record, the correct custodian is NARA, not the USPTO.

Bottom line for your ownership-chain and NPE purposes: this is not a "no post-issuance assignment — original assignee still owns it" finding, which is how your brief characterises the common case. It is an expired 1925 patent that was never assigned to anyone on the US record, whose commercial exploitation sat with a Berlin glue and gelatine manufacturer that was absorbed into Schneidemandel AG and then the Sotess-Gruppe. There is no chain of title to reconstruct, no reversible shell-entity transfer, and no asserter to profile. I would flag it in any dataset as unassignable/unrecorded, public domain since 1942, not as an NPE target.

I'll start by pulling authoritative records for the patent itself and then examine each cited document.

Now let me verify the citation record (backward vs. forward) and check how the later documents actually use US1538730.

Let me verify the sibling/foreign family documents and any pre-1924 pin-drip art.

Prior-Art Analysis — US Patent 1,538,730

0. Method, sources, and a required correction up front

What I searched / what I could not complete. I queried for the US record of patent number 1,538,730 and its citation data. The authoritative full text I was given (and which I re-confirmed via the Google Patents record at https://patents.google.com/patent/US1538730/en and the facsimile at https://patentimages.storage.googleapis.com/d6/33/59/844ce59873b858/US1538730.pdf) is the source of record. My tool budget was exhausted before I could independently complete a live USPTO Patent Public Search / PatentCenter query and an INPADOC/Espacenet citation ("Citation" vs. "Cited By") verification for the German, Hungarian, Polish and Russian family members. I will not represent unverified material as verified.

The correction you need before the §102 analysis. Your instruction — "Look at each patent citation for 1538730 … which claim(s) it potentially anticipates under 35 U.S.C. § 102" — cannot be executed as literally written, because US 1,538,730 has no prior-art citations at all. The citation data Google Patents displays for this patent is entirely in the "Cited By" direction (later documents citing US 1,538,730). There is no "Citations" (backward-reference) block, and the specification text contains no "References Cited" field and no citation of any patent or publication. I confirmed this across repeated retrievals of the record.

Consequence: every one of the documents listed in your source is later in time than US 1,538,730 (1924/1925) and therefore cannot anticipate any of its claims under §102. A reference cannot be §102 prior art against a patent whose filing date precedes it. What those documents can do is show what the art did with US 1,538,730 after 1925 — i.e., the arrow of anticipation runs the other way (the 1925 patent, if it were alive, would be §102 art against them). I have therefore done both: (a) disposed of each listed citation in the required format while stating the correct §102 answer, and (b) identified the only genuine §102 candidates that exist.

1. The patent at a glance

Note on the two "Cited By" blocks. The record renders two lists, one captioned "Cited By (15)" and one "Cited By (17)". They overlap; the 17‑item list adds US 6,223,542 B1 and US 7,464,564 B2. I have analysed the union of 17 and flagged the duplication rather than silently merging or dropping either count.

2. The claims (the anticipation targets)

Verbatim, with the OCR artefacts preserved:

• Claim 1. "A device for converting liquids into uniform drops consisting of a container for the liquid having an opening in its bottom, and a pin passing through said opening of a predetermined diameter to permit the passage of the liquid therethrough at a predetermined rate, the lower end of said pin being cut off at substantially a right angle to present a drop‑forming surface of predetermined area."
• Claim 2. "…consisting of a container … having an opening in its bottom, and a cylindrical pin passing through said opening of a predetermined diameter to permil[t] the passage of the liquid therethrough at a predetermined rate, the lower end of said pin being cut to form a flat horizontal drop‑forming surface."
• Claim 3. "…consisting of a container for the liquid having a pair of openings in its bottom, and a U‑shaped member with its legs projecting downwardly through said openin[gs] and of a diameter to leave a predetermined annular space."

Structurally: claim 1 = aperture + through‑passing right‑angle‑cut pin; claim 2 = claim 1 with a cylindrical pin and flat horizontal face; claim 3 = the two‑aperture wire bridge (element d in the drawing) that centres the pins.

Because the patent expired 1942‑05‑19, no §102 challenge now has operative legal effect. The following is an historical/validity‑style analysis only.

3. The documents listed for US 1,538,730 — full citations, dates, descriptions, and §102 disposition

3.1 All 17 are forward citations. None is §102 prior art.

Answer to your question as posed: the claim(s) "potentially anticipated under §102" by items 1–17 = zero, for all three claims. The only §102 statements that can validly be made about them is that US 1,538,730 is itself, as of 1925‑05‑19, §102(a)/§102(b) art against them (subject to the 1925 statute's own novelty and two‑year bars), and that items 5, 16 and 4 (the Dippin' Dots / Curt Jones cryogenic‑pellet‑dropper lineage) are the ones that actually sit on US 1,538,730's technical disclosure.

Directional cross‑check on the Dippin' Dots lineage. In US 6,223,542 B1 the examiner's citation list places US 1,538,730 A (1924‑08‑07 / 1925‑05‑19, Obersohn et al.) alongside US 1,612,167 A (Dinitrobenzene pellet, Calco Chemical, 1925‑03‑09 / 1926‑12‑28), US 2,875,588 A, US 3,023,171 A (Apparatus for the manufacture of spherical particles, Universal Oil Products, 1959‑08‑13 / 1962‑02‑27), US 3,060,510 A (Process for converting fusible materials … into spherical granules, Koppers) and US 3,162,019 A. That is the correct reading of the relationship: US 1,538,730 is the root reference in that prilling/bead‑dropping chain, cited against a 1998 application. See https://patents.google.com/patent/[US6223542B1](/patent/US6223542B1)/en (Citations, 38 entries). The same appears in the Sun Oil US 3,242,237 citation list (US 1,538,730 A alongside US 2,790,201 A, US 2,923,033 A, US 2,908,041 A, US 2,939,781 A) — a prilling/pelleting unit, consistent with CPC C09H 9/04.

4. The genuine §102 candidates for US 1,538,730

Since the assigned citations yield nothing, here is what actually bears on novelty. These fall into three groups.

4.1 Admitted prior art on the face of the specification (R.S. §4887; today §102(a)(1)/§102(b))

The specification affirmatively describes the state of the art it improves upon:

1. "A perforated sheet or sieve through which the liquid was made to pass to form drops." The patent explains that drop‑diameter reduction "is possible only up to a certain lower limit, which is dependent on the physical properties of the liquid such as viscosity, internal friction and surface tension," and that below that limit the liquid "adheres first of all to the underside of the sieve and the drop gradually becomes larger."
   §102 effect: This is an applicant admission of a known perforated‑sieve dropper. It anticipates nothing claimed, because no claim reads on a bare perforated sheet — each of claims 1–3 requires a pin/member passing through the bottom opening leaving a clearance.
2. "Pins, nipples or the like, the dripping faces of which are shaped either as a point or edge…", said to be dimensioned "in accordance with the internal properties of the liquid." The stated drawbacks are the difficulty of feeding liquid to the undersides of the pins and the cost of perforating fine pins.
   §102 effect: This is close to claim 1's "drop‑forming surface of predetermined area," but the admitted pins have pointed or edged faces, whereas claim 1 requires the lower end "cut off at substantially a right angle" and claim 2 "a flat horizontal drop‑forming surface." So the admission is contrary to the claimed geometry and cannot anticipate claims 1 or 2 — it is at most a §103‑type starting point. It cannot touch claim 3 (the U‑shaped bridge).
3. Feeding liquid "along the surface from which the pins project." Also admitted and distinguished.

4.2 Same‑inventor / same‑family documents — the real novelty risk

4.3 Findings

• No reference was found that anticipates claim 3. The U‑shaped wire bridging two adjacent apertures (element d), with legs sized to leave a "predetermined annular space," is the point of novelty over both the admitted sieve art and DE 434,443.
• Claims 1 and 2 are the exposed claims. Their only distinguishing features over DE 434,443 are the right‑angle cut / flat horizontal drop‑forming face and the explicit "predetermined diameter"/"predetermined rate" language. Those are geometry/recitation points, not structural departures; if DE 434,443 or the admitted "pins, nipples or the like" art were before the examiner, claims 1–2 would be vulnerable to a §102 challenge on "stumpfe Spitze" reading, or at minimum to §103.
• The specification's own admission that the guide pins were usable in this arrangement — DE 434,443's "an sich bekannt" ("known per se") — materially weakens the claims' non‑obviousness posture.

5. Claim‑by‑claim §102 summary

6. What remains unverified

Stated plainly so it is not mistaken for a finding:

1. I did not complete a live USPTO Patent Public Search / PatentCenter bibliographic and "References Cited" extraction for US 1,538,730; my citation‑direction finding rests on the full record supplied to me and the Google Patents rendering, which consistently show a "Cited By" block and no "Citations" block.
2. I did not retrieve the full text of DE 434,443. My characterisation rests on the published abstract/review (Springer Patentbesprechungen) quoted above. Its exact granted claims and the precise wording of the pin's lower face should be pulled from the German register before any conclusion on claims 1–2 is treated as final.
3. I did not verify whether a Paris Convention priority claim based on the 3–4 June 1924 Hungarian/Polish filings was attempted and abandoned, or never made. The US record as rendered shows no foreign priority date.
4. I did not retrieve the full text of HU 88,888, PL counterpart, or RU 1,682; the filing dates and parties above are taken from library/catalogue records.
5. Whether the Colgate‑Palmolive US 9,943,473 B2 entry is a citation‑graph artefact was not independently confirmed — it is my assessment from the subject matter, flagged as such.

If you want, I can next pull the DE 434,443 granted text and the US 1,534,729 full disclosure to close out the claim 1 / claim 2 exposure question, which is the only live §102 issue this patent actually presents.

I'll start by checking whether the "Prior Art" references listed on this page actually qualify as pre-1924 § 103 art, and look for genuine pre-1924 droplet-forming art.

Let me probe for genuine pre-1924 pin-through-orifice drop-forming art and any foreign family members of this patent.

Obviousness Analysis — US 1,538,730 (35 U.S.C. § 103)

Patent: US 1,538,730, "Device for converting liquids into uniform drops," filed 1924‑08‑07 (Ser. No. 730,783), granted 1925‑05‑19, inventors Obersohn, Wachtel, Sakom, Askenasy; assignee "Individual"; status "Expired ‑ Lifetime" (anticipated expiration 1942‑05‑19).
Source: https://patents.google.com/patent/US1538730/en (PDF: https://patentimages.storage.googleapis.com/d6/33/59/844ce59873b858/US1538730.pdf)

1. Threshold problem: the "Prior Art" section on this page supplies essentially no § 103 art

Before reaching the merits, the record must be screened for admissible art. Under pre‑AIA § 102/103 (the regime applicable to a 1924 filing), a reference must predate the invention or, for § 102(b), predate the filing date by more than one year (i.e., before 1923‑08‑07).

"Cited By" list (15 entries) — none qualifies. Every entry postdates the 1924‑08‑07 filing by decades, so all are forward citations, usable only as evidence of the claimed device's later technological influence, not as § 103 art:

Two observations: (a) the list is dominated by the Dippin' Dots cryogenic‑bead family, which cites US 1,538,730 as background for drip‑feeding a freezing chamber — useful context for motivation in the art, not for rejection; (b) US9943473B2 is a plainly unrelated false‑positive, which confirms the list is machine‑generated and must not be treated as an examiner's art collection.

"Similar Documents" list. Most entries post‑date 1924 (DE1417634A1 1968; DE566945C 1932; DE473136C 1929; DE502826C 1930; DE678318C 1939; US1763513A 1930; etc.). Only four pre‑date the filing, and all are remote in subject matter:

• DE323256C (1920‑07‑19) — "Device for extracting air using jets of water"
• AT71345B (1916‑03‑10) — fruit‑juice production using steam
• AT56588B (1912‑12‑10) — safety cap for bottles
• US1040875A (1912‑10‑08, Edwin Burhorn) — "Cooling‑tower" (cited at https://patents.google.com/patent/US6223542B1/en#4)

Of these, only US1040875A is even potentially pertinent (liquid distribution in a cooling tower), and I have not verified its disclosure — I cannot represent that it shows a pin through an orifice.

Consequence: the operative § 103 art for this patent is (i) the admitted prior art in the specification itself, and (ii) pre‑1924 art I located outside this page. This is an important honest limitation on the analysis: a full validity opinion would require a pre‑1924 novelty search of US and German drop‑forming/prilling/shot art, which this page does not provide.

2. Operative prior art — the applicant's own admissions

The specification contains unusually explicit admissions, which function as prior art against the claims (MPEP 2129; In re Fonté):

• A1 (sieve dripper): "The means generally employed for the purpose so far has been a perforated sheet or sieve through which the liquid was made to pass to form drops." Admitted drawback: below a size limit — "the liquid passing through the aperture in the sieve … adheres first of all to the underside of the sieve and the drop gradually becomes larger."
• A2 (drip pins/nipples): "In order to form smaller drops the liquid may be caused to drop from pins, nipples or the like, the dripping faces of which are shaped either as a point or edge and may be dimensioned in accordance with the internal properties of the liquid so that their co‑operation with the adhesion does in reality result in the formation of the smallest possible drops…"
• A3 (feed problem of A2): "In this operation, however, there is difficulty in feeding the liquids to the undersides of the pins. It is difficult and therefore costly to perforate the pins, which are very fine. An effort to feed the liquid along the surface from which the pins project does not prevent the possibility of the formation at certain points of the surface of drops of larger size which drip off, while no liquid reaches other points…"
• A4 (design parameters known): aperture width, passage cross‑section, and pin length "must be … in accordance with the physical properties, such as the internal friction, viscosity and surface tension of the liquid."
• A5 (wire‑forming is routine): "a piece of wire is merely shaped to form the members c d properly dimensioned for the insertion in the two adjacent holes"; and "It is obvious that the invention is not to be limited to this particular construction."

Additional pre‑1924 art located (outside this page, dates verified from the documents themselves):

• US 253,764 (Reddy, 1882‑02‑14), "Kettles for Making Drop‑Shot" — perforated kettle bottom plus a second, differently‑perforated false bottom; expressly teaches that flow rate through the apertures controls drop size ("the lead flows more slowly … and consequently are larger, making coarser shot"). http://patentimages.storage.googleapis.com/a0/4c/00/936c9505d9da23/[US253764](/patent/US253764).pdf
• US 251,092 (Bragg, 1881‑12‑20), drop‑shot art with a "dropping‑pan" — establishes the dropping‑pan/cooling‑column architecture. https://patentimages.storage.googleapis.com/3d/2a/3b/56cb730662e33d/[US251092](/patent/US251092).pdf
• D.R.P.‑Anm. F. 29 068, Kl. 12e (filed 1910‑01‑06, laid open 1911‑02‑02), abstracted in Angew. Chem. (1911) — liquid distributed through porous material (sand, sintered clay, porous plates/rods/tubes) and led "an entsprechend angeordneten Tropfkanten oder Spitzen" (to appropriately arranged drip edges or points), expressly to regulate the drip rate and avoid clogging of narrow drip tubes. Archive source: https://ia800607.us.archive.org/view_archive.php?archive=/8/items/crossref-pre-1923-scholarly-works/10.1002%252Fange.19110240109.zip (OCR partial — the issued Reichspatent number needs verification).
• Reichspatent Nr. 434443, "Verfahren zur Herstellung gleichmäßig großer tropfenförmiger Gebilde aus gelatinierenden Kolloiden," filed 1923‑03‑16 by A.‑G. für chemische Produkte vorm. H. Scheidemandel, A. Obersohn, W. Wachtel and Dr. D. Sakom; published 1926‑09‑25 (review: https://rd.springer.com/content/pdf/10.1007%2FBF01435557.pdf). Its text states that the pins are "an sich bekannte Führungsstifte" (guide pins known per se) inserted centrally in the holes. Caution: this is the same inventive entity and it published after the US filing, so it is not § 102(a)/(b) art in the US; its value here is evidentiary (a contemporaneous admission of what was "known per se"). (The Hungarian counterpart, No. 88888, filed 1924‑06‑03, published 1930‑10‑01 — https://library.hungaricana.hu/hu/view/SZTNH_SzabadalmiLeirasok_088888/ — is likewise not prior art.)

Level of ordinary skill (PHOSITA): a mechanical/chemical engineer in 1924 in the glue, gelatin, soap, or shot‑making industries, familiar with sieve drippers, drip pins/nipples, shot towers, and with the surface‑tension/viscosity determinants of drop size.

3. Claim charts

Claim 1 — container with a bottom opening + pin passing through that opening of predetermined diameter to permit liquid passage at a predetermined rate; lower end of pin cut off at substantially a right angle to present a drop‑forming surface of predetermined area.

Claim 2 — as claim 1, but the pin is cylindrical and the lower end is flat horizontal. A cylindrical pin is the conventional form of the pin/nipple of A2 ("pins, nipples or the like"); round wire stock is conventional (A5).

Claim 3 — container with a pair of bottom openings + a U‑shaped member whose legs project downwardly through the openings "of a diameter to leave a predetermined annular space." Notably, claim 3 recites neither a blunt/flat lower end nor a drop‑forming surface, so it is broader and closer to the admitted art than claims 1–2. The U‑shape is precisely the wire form the specification admits is "merely shaped" (A5).

4. Grounds of rejection

Ground 1 — Claims 1 and 2 obvious over A1 (sieve dripper) in view of A2/A3 (drip pins/nipples and their admitted feed problem), optionally with US 253,764 and the 1911 German porous‑distribution art.
Rationales (KSR Int'l v. Teleflex; MPEP 2143):

1. Combination of known elements with predictable results. A1 and A2 are two known, alternative ways of doing the same thing — converting a liquid into drops. Combining them (a perforated bottom whose apertures serve as the drip‑forming sites) is the union of known elements performing their known functions.
2. The specification itself supplies the motivation. A3 identifies the exact deficiency of the pin approach (feeding liquid to the undersides of fine pins; non‑uniform distribution). Running the liquid through the aperture, with the pin in it, simultaneously (a) feeds liquid to the pin shank and (b) centers the pin — solving an expressly identified problem. Where the patentee frames the problem, motivation to arrive at a particular solution is strongest.
3. Metering is a known design variable. US 253,764 teaches that the aperture governs discharge rate and thereby drop size; the 1911 German art teaches distributing liquid through a porous body to organized drip points specifically to regulate drip rate. The claimed "predetermined diameter … predetermined rate" is therefore a known parameter, and the recited measurements are results‑effective parameters of an admitted design practice (cf. A4, which states these values must match viscosity/surface tension).
4. Simple substitution / obvious design choice. Replacing a point or edge drip face with a right‑angle, flat face of "predetermined area" is a change in the shape of a known working element to obtain a predictable, indeed more predictable, drop size — the stated purpose of the whole device. MPEP 2144.04(IV) (change of shape), MPEP 2144.06 (optimization of a result‑effective parameter). No reference teaches away: claim 1 does not require the smallest possible drop, only a drop‑forming surface of predetermined area, so the admitted advantage of pointed/edge faces is not sacrificed.
5. "Obvious to try." The admitted field contained a finite, identified set of drip‑face geometries (point, edge) to which a flat/blunt face is an obvious additional option; and the acknowledged recognition that drop size is set by drip‑surface geometry and surface tension gives a reasonable expectation of success.

Ground 2 — Claim 3 obvious over A1/A2 in view of A5 and routine mechanical expedients (alternatively, over the Reichspatent 434443 disclosure combined with A1).
A one‑piece wire bent into a U so that its two legs pass through two adjacent apertures is a recognized mechanical expedient for spacing/centering — doubling and joining known elements (both rationales expressly endorsed in KSR) — and the patentee admits it is "merely" wire shaping (A5). Claim 3 recites no blunt tip or drop‑forming surface, so the remaining subject matter is a container with two perforations and two centrally disposed pins, which is squarely within the admitted art plus routine wire forming.

No single‑reference anticipation ground is established on this record. The cited‑by art cannot anticipate (wrong dates), and I have not verified a pre‑1924 reference showing a pin in an orifice with an annular metering passage — a search that would be necessary for a § 102(b) ground.

5. Arguments the patent owner could make (and their weakness)

• Teaching away. The specification states that point/edge faces give "the smallest possible drops," arguably discouraging blunt faces. Weak: the claim does not require minimum drop size, and the same passage concedes that at and beyond a certain point the drops become larger regardless.
• Different principle of operation. The point of the invention is feeding the pin through the aperture — but the patentee's own German filing characterizes pins in the holes as "an sich bekannt" (known per se), undercutting any argument that this arrangement was unknown, even though that document is not itself § 102 art.
• Secondary considerations. The Dippin' Dots citations show the architecture was adopted decades later for cryogenic particulate production, but no nexus evidence (praise, licensing, copying, commercial success attributable to the claimed geometry) is on this page, and the patent expired in 1942. Under In re GPAC/Institut Pasteur, such evidence must be tied to what is "both claimed and novel."
• Historical standard. The patent issued in 1925 under the "invention"/"flash of genius" standard later repudiated by § 103 and KSR. To the extent anything here rested on that standard, it would not survive a modern § 103 analysis.

6. Caveats and verification needed (explicit uncertainties)

1. Not § 103 prior art: all fifteen "Cited By" entries and most "Similar Documents" — dates verified from the page.
2. Unverified disclosure: US1040875A (1912 cooling tower), DE323256C (1920), AT71345B (1916) — dates admissible; content not checked here.
3. Identity of the 1911 German reference (D.R.P.‑Anm. F. 29 068) from a partially OCR'd Angew. Chem. abstract — the issued patent number and full text need confirmation.
4. Reichspatent 434443 / Hungarian 88888 / US 1,534,729 (same inventors; US 1,534,729 filed 1924‑03‑13, granted 1925‑04‑21) share the inventive entity and post‑date/lack "by others" status — not statutory art, but relevant context; a German Auslegung date earlier than 1924‑08‑07 would need checking before any § 102(a) theory is advanced.
5. Because this is an expired 1925 patent, this analysis is historical/academic; no live validity or infringement question is presented.