US 1861774

I'll research this patent number across the specified sources.

Let me run additional targeted searches for litigation and docket records.

US Patent 1,861,774 — Research Summary

Search scope note: Searches were run against Google Patents (which mirrors USPTO full-text/imaging data), general web, and CAFC-related sources. No CAFC 2026 docket, PTAB proceeding, or district-court litigation referencing U.S. Patent No. 1,861,774 was found. The only "1861774" hits outside the patent were unrelated identifiers (EP 1861774 A2, "System and Method for Managing Listings"; MGI:1861774, a mouse gene ID; SEC CIK 1861774, SoundThinking Inc.; and a 2023 WL reporter cite "2023 WL 1861774" from a PTAB decision in Palo Alto Networks v. Centripetal Networks, which is a Westlaw number, not this patent). These are noted only to show they were checked and excluded as non-matches.

Bibliographic Data

Abstract

The patent has no formal abstract — it predates mandatory abstracts in US practice. Based on the specification, the invention is a vibrating massage-and-exercise machine in which an electric motor drives a vertical shaft through selectable belt-and-pulley speed-changing gearing and a clutch; an eccentric mechanism at the top of the shaft converts rotation into oscillation of a pivoted rocker arm carrying interchangeable body applicators. All moving parts except the applicator ends and the amplitude-adjusting knob are enclosed in a casing.

Independent Claims — Plain Language

All three claims are independent (no claim depends on another). I read the claim text directly from the patent's own claim section.

Claim 1 — A massage and exercise machine built on a rigid frame: a base; several upright pillars adjustably supported on the base; a top plate carried on the pillars' upper ends; an applicator-supporting arm movably mounted on the top plate; a motor mounted on the pillars; a speed-changing mechanism positioned between the pillars and mounted on brackets carried by the pillars; translation means (connected to the speed changer and motor) that converts rotational motion into vibratory motion of the arm; and a casing that entirely surrounds both the pillars and the top plate. The core novelty is the integrated pillar-frame architecture enclosed by the housing.

Claim 2 — Everything in claim 1, plus: the casing is formed with an inwardly extending compartment for storing applicators, and a speed-changing control lever is located inside that compartment (so the operator opens the compartment door to change speed). Adds the storage/control-integration features to the enclosed frame.

Claim 3 — Everything in claim 2, plus: the casing has a door whose inner wall carries fixed applicator-supporting clamps, and the speed-changing control lever remains disposed within the compartment. Adds on-door applicator storage to the claim 2 combination.

Key Embodiment Detail (from the specification)

• Motor C on plate 15 clamped at 16 to the rear pair of pillars K; belt 19 from pulley 18 to large pulley 20 on idler shaft 21.
• Two alternate driven pulleys 25/26 with a feathered clutch disc 27 between them, selectively engageable to give two shaft speeds; belts 42/43 drive pulleys 44/45 keyed to vertical shaft E.
• Shift lever 36 in compartment N connected by rod 37 to finger 38 engaging groove 40 on the clutch — the claimed "speed changing control lever... disposed within said compartment."
• Eccentric mechanism F at the top of shaft E inside a depressed portion 55 of head plate J; spindle 68 movable diametrically across circular body 58 by hand grip 89 (adjusting mechanism G) to vary stroke amplitude without altering the complementary motion of the two ends of rocker arm A.
• Connecting rod 92 journaled at 93 to spindle 68 and at 94 to rocker arm A off the pivot axis 95; frictionless bearings throughout with lubricating passages.
• Applicators described: broad and narrow belt applicators 104/105, soft-rubber vacuum cup 106 with air valve 138, pad 107 on rod 109 with sliding grip sleeve 140, and bar applicator 110 for two-handed upper-body exercise. Upper casing 115 with removable plate 116 covers the eccentric mechanism; switch 119 controls the motor.

Uncertainty / Caveats

• No CAFC 2026 docket information found. To the extent one exists, I could not locate it; the term "1861774" in Federal Circuit–adjacent material traced only to a Westlaw citation number, not to this patent. Treat the litigation question as unresolved rather than affirmatively "no litigation."
• Inventor name rendering: Google Patents gives "Fritz A Anderson"; the printed patent's OCR is corrupted ("FRE'LZ A. ANDERSON"). I did not auto-correct the OCR; "Fritz A. Anderson" is the reading supported by the secondary source. The signed witness date of September 27, 1928 precedes the October 1, 1928 filing date, which is consistent.
• Assignee: Google Patents lists Burdick Corp as both original and current assignee. The specification's printed assignment statement (OCR-garbled) supports "Burdick Corporation, of Milton, Wisconsin, a corporation of Delaware."
• Do not confuse with U.S. Patent 1,830,380, also titled "Massage and exercise machine," filed April 30, 1928 (a related but distinct Anderson/Burdick-era document cited against other patents), nor with US 1,851,774, which appears as an OCR error in one drawing heading of this patent's own printed text.

I'll search for litigation records involving US patent 1861774.

Let me check the suggested litigation databases and search for the patent owner's enforcement history.

Result: No litigation found involving U.S. Patent No. 1861774

I searched the sources you specified (Unified Patents Portal litigation case list, Federal Circuit materials, PACER-adjacent dockets, and general web/reported-case searches) for the literal identifier 1861774 and for the patent's front‑page data. I found no district court case, ITC investigation, PTAB/post‑grant proceeding, or CAFC appeal in which U.S. Patent No. 1861774 is the patent‑in‑suit.

What I checked and what came back

I did not return or rely on similarly-numbered but distinct references that surfaced, e.g., EP 1861774 A2 ("System and method for managing listings"), U.S. App. No. 18/617,774 / SEC CIK 1861774, or Brazilian REsp nº 1861774 — none of these concern this patent.

Why the absence is expected

• Per the patent's own record (as fetched): US 1861774, "Massage and exercise machine," inventor Fritz A. Anderson, assignee Burdick Corp (Milton, Wisconsin), filed October 1, 1928 (App. No. US309561A), granted June 7, 1932, and "Anticipated expiration" June 7, 1949. The patent has been expired for over 75 years and is not enforceable today, so modern assertion is legally impossible.
• Database coverage limits: The commercial dockets (Unified Portal, Docket Navigator, PACER) generally reach back only to the 1990s–2000s, and reported decisions from the 1930s–1940s are not comprehensively indexed in those tools. The claims here (three claims, all directed to the base/pillars/top‑plate/casing/applicator‑compartment combination) would only have been assertable between 1932 and 1949.

Important caveat (intellectual honesty)

I found no evidence of litigation, but I want to be explicit about the limits of that statement:

• I cannot certify a negative for the 1932–1949 enforcement window. Vintage federal court opinions, Burdick Corp. enforcement actions, or unreported settlements from that era may exist in print sources (e.g., Federal Cases, West reporters, the Burdick corporate archives) that are not surfaced by the tools I searched. If a 1930s–40s suit against a competing vibrator maker exists, it would most likely be captioned Burdick Corp. v. [defendant], brought in the Eastern District of Wisconsin or the Seventh Circuit venue for a Milton, Wisconsin assignee — but I have no source confirming any such case, and I am not asserting one.
• Google Patents' litigation field for this record is empty, which is consistent with (but not proof of) no litigation.

Bottom line: Based on the searches performed, there is no known litigation involving U.S. Patent No. 1861774. If you are specifically interested in historical 1930s–1940s enforcement, that would require manual review of print reporters and the Burdick Corporation records, which is outside what these databases cover.

Proceedings overview

Zero AIA trial proceedings exist on U.S. Patent No. 1,861,774 — 0 active, 0 instituted, 0 claims canceled, 0 claims sustained, 0 settled, 0 denials — because no IPR, PGR, or CBM petition has ever been filed against this patent, and the defensive posture is not "hardened patent" but the opposite: the patent expired on 1949-06-07 and any assertion of it today is legally baseless. The structured "PTAB proceedings on file" block (USPTO Open Data Portal) returns no AIA trial proceedings, and independent web searches for any PTAB record tying "1861774" to this patent returned nothing but non-matches (detailed below). This is the correct and expected result — it is not a data gap.

No proceedings to report

Non-matches checked and excluded. Every web hit on the string "1861774" in a PTAB/CAFC context traces to something other than this patent and must not be mistaken for it:

• 2023 WL 1861774 — this is a Westlaw citation number, not a patent number. It corresponds to Palo Alto Networks, Inc. v. Centripetal Networks, LLC, No. IPR2021-01147 (P.T.A.B. Feb. 9, 2023), aff'd, Nos. 2023-1654, 2023-1655 (Fed. Cir. Oct. 31, 2024). The patents at issue there were U.S. 10,542,028 and 10,757,126 ("Rule-Based Network-Threat Detection"). See the Fed. Cir. opinion summary at https://fedcircuitblog.com/2024/10/31/opinions-orders-october-31-2024/ and the Board paper at https://www.docketalarm.com/cases/PTAB/IPR2021-01148/Palo_Alto_Networks_Inc._v._Centripetal_Networks_Inc/. Neither the proceeding nor the patents involve U.S. 1,861,774.
• MGI:1861774 — a mouse gene ID (Rbms1), per the Jackson/ModelOrg strain sheets. Not a patent.
• STJ Recurso Especial Nº 1861774 (RS) and TJ-DF 1861774 — Brazilian court case numbers. Not patents, not US.
• SEC CIK 1861774 — SoundThinking, Inc. Not this patent.
• EP 1861774 A2 — "System and Method for Managing Listings." A European publication number, unrelated.
• The line "The Anderson test was refined in Burdick v. …" that surfaces in a general search is a voting-rights case cite (Anderson–Burdick balancing test), not the Burdick Corporation. Pure lexical coincidence.

Why no AIA trial could exist here (statutory/structural limits)

This matters because it converts "no proceedings found" from an evidentiary gap into a legal conclusion. Applying the AIA trial statutes to this docket:

• Post-Grant Review (35 U.S.C. §§ 321–329) is available only for patents with an effective filing date on or after 2013-03-16 (AIA § 6(c)(2)(A)). U.S. 1,861,774 was filed 1928-10-01. PGR is categorically unavailable. Full stop.
• Covered Business Method review (AIA § 18) was limited to patents with claims covering a "financial product or service," and the program sunset on 2020-09-16. Even setting aside that this is a mechanical massage apparatus classified in A61H, the CBM door is closed.
• Inter Partes Review (35 U.S.C. §§ 311–319) is, as a matter of statute, not limited by filing date and can technically be brought against an expired patent in narrow circumstances. But there is no live claim scope to invalidate: the patent's term ran 17 years from issuance under pre-1995 law, i.e., issued 1932-06-07, expired 1949-06-07 (Google Patents lists the anticipated expiration as 1949-06-07). No petitioner has any incentive — and no accused infringer any exposure — that would generate a petition. Predictably, none was filed.
• Note the statutory IPR bars for completeness: 35 U.S.C. § 315(b) (one-year bar from service of an infringement complaint) and § 315(e)(2) (estoppel). These are academic here because no proceeding was ever instituted.

I found no PTAB decision, institution order, or Board paper naming U.S. 1,861,774 on PTAB E2E, the USPTO PTAB Decisions search, or CourtListener. If a proceeding surfaces after this analysis, treat it as new data and re-run — but there is no basis to expect one.

Strategic summary

All three claims — 1, 2, and 3, the patent's entire claim set — are UNTESTED by the PTAB, and this is irrelevant to the defensive analysis because all three claims are also unenforceable by expiration. Independent claim 1 (base + adjustably supported upright pillars + top plate + applicator-supporting arm + pillar-mounted motor + bracketed speed-changing mechanism between the pillars + rotational-to-vibratory translation + casing entirely surrounding the pillars and top plate), claim 2 (adds the inwardly extending applicator compartment with the speed-change lever inside it), and claim 3 (adds the door with applicator clamps on its inner wall) were never challenged, never narrowed, and never canceled. There is no FWD to cite, so do not construct any argument — offensive or defensive — that depends on PTAB claim-level outcomes. The claim text in the specification is the only authoritative claim scope, and it is what it was in 1932.

The estoppel landscape is empty, and the prior-art landscape is wide open in the only forum that matters. Because no IPR was instituted, no petitioner is subject to § 315(e)(2) estoppel, so there is no estoppel bar to overcome in district court. More importantly, a defendant's real defenses are statutory, not art-based: 35 U.S.C. § 271(a) infringement requires an unexpired patent, and this one lapsed on 1949-06-07. Prior art from 1928 and earlier is abundant and would have been lethal in the 1930s — the closest sibling is the same inventor's own U.S. 1,830,380 ("Massage and exercise machine," filed 1928-04-30, issued 1931-11-03, Anderson/Burdick, https://www.freepatentsonline.com/1830380.html), and a second sibling is U.S. 1,866,833 (filed 1928-11-20, issued 1932-07-12, https://patents.google.com/patent/[US1866833](/patent/US1866833)) — but if someone is waving this patent at you today, invalidity briefing is unnecessary. Your first exhibit should be the 1949 expiration date.

Pattern signals are absent by construction. No petitioner has filed once, let alone repeatedly; the patent owner (Burdick Corporation, now listed as Burdick Corp) has never pursued a PTAB appeal; no defensive aggregator (Unified Patents, RPX, Allied Security Trust) appears anywhere in the chain. The truism that "well-asserted patents eventually attract IPRs" does not apply here, and its non-application is not a signal of patent strength — it is a signal that no one has ever had a reason to assert a 1949-expired patent. Any present-day demand letter that cites U.S. 1,861,774 as a basis for payment is asserting a public-domain document.

Recommended next steps

• If you are a defendant / recipient of a demand: you do not need an IPR, and you should not file one — there is nothing to invalidate and no live claim to cancel. Do not wait for a PTAB record or an FWD that will never issue. Respond with the expiration fact: U.S. Patent No. 1,861,774 issued 1932-06-07 and expired 1949-06-07 (17-year pre-1995 term; Google Patents records the anticipated expiration at https://patents.google.com/patent/[US1861774](/patent/US1861774)/en). Frame the demand as meritless and evaluate remedies under 35 U.S.C. § 285 (exceptional case/fee shifting if suit is filed), Fed. R. Civ. P. 11, and applicable state unfair-competition/extortionate-demand-letter statutes. Preserve the letter and any follow-up correspondence.
• If you are asked to assess "PTAB risk" on this patent internally: the answer is that risk is nil, and the reason is statutory rather than evidentiary. Cite the three AIA gates above — PGR filing-date bar (2013-03-16), CBM sunset (2020-09-16), and the practical impossibility of a meaningful IPR against a 1949-expired patent. This is a stronger, cleaner answer than "we searched and found nothing."
• If you simply want to confirm the negative yourself: query the USPTO Patent Trial and Appeal Board E2E system and the USPTO PTAB Decisions database by patent number "1861774" and separately by "1,861,774"; run the same terms on CourtListener and the Federal Circuit docket. Expect zero results and ignore the Westlaw-citation and gene-ID noise described above.
• Trial-stage milestones (not applicable): there are no pending proceedings, so there is no institution-decision deadline, no oral hearing date, and no one-year § 316(a)(11) FWD due date to track.

Caveat. My conclusion is that no AIA trial proceeding on U.S. 1,861,774 exists; I did not and cannot rule out a filing made after the most recent USPTO ODP ingest. The structural analysis above, however, means such a filing would be legally anomalous rather than merely undiscovered, and the expiration date makes the point moot regardless.

I'll research the assignment/ownership chain for this patent. Let me run targeted searches.

Let me verify two specific factual points: (1) the historical coverage limit of the USPTO assignment database, and (2) the fate of the Burdick Corporation.

Let me check whether Burdick commercialized this machine and confirm Google Patents shows no recorded assignments.

Inventors

Unusual-pattern check — negative. There is no evidence of inventor flight preceding a portfolio sale:

• Anderson is a repeat Burdick inventor, not a one-off. He is the named inventor on US 1,830,380, "Massage and exercise machine," filed 1928-04-30, issued 1931-11-03, also assigned to Burdick Corp (freepatentsonline.com/1830380.html). Two massage-machine filings four months apart, both assigned to the same Milton, Wisconsin operating company, indicates a continuing in-house engineering relationship rather than a departing inventor.
• The purported identical assignor/assignee on both cases is the strongest available signal that Anderson was a Burdick employee or retained engineer. I could not independently confirm an employment agreement (no personnel records surfaced).
• Caveat: I did not attempt to build a full Anderson patent list; later patents listing an "Anderson" (e.g., US 3,096,410, 1963) are almost certainly a different individual and I do not attribute them here.

Original assignee

The Burdick Corporation, Milton, Wisconsin, a corporation of Delaware (Google Patents renders the current assignee simply as "Burdick Corp").

• Primary line of business: Electromedical apparatus for physical therapy and diagnostic cardiology. Burdick was founded in 1913 as the Burdick Cabinet Co. and by the 1930s–60s sold diathermy units (MF-490, MW-1/MW-200 microwave), muscle stimulators (MS-600, Z-12 Zoalite galvanic-faradic), ultrasound (UT-400), infrared lamps (Z-500), and direct-recording electrocardiographs — all advertised from "THE BURDICK CORPORATION, MILTON, WISCONSIN" (Physical Therapy journal advertisements, e.g. academic.oup.com/ptj/issue-pdf/44/2/22765998 and /46/4/22751466).
• Did they ship a product embodying the claims? Burdick demonstrably shipped vibrating/therapeutic massage hardware — e.g., a "Vintage Burdick electric therapeutic massager" (bell-shaped porcelain base, chrome motor housing) offered on the secondary market (liveauctioneers.com item 234851585). That unit is a massager, and whether it practices these specific claims (base + adjustable pillars + top plate + speed-changer bracketed between pillars + a casing that entirely surrounds the pillars and top plate + applicator compartment) cannot be confirmed; the claimed architecture is a floor-standing cabinet machine, and no surviving catalog cut of a Burdick cabinet exerciser was located. Treat "shipped the claimed embodiment" as probable but unverified.
• Current status: No longer an independent operating company; the legal entity was absorbed through a chain of M&A (see timeline). The brand survives under Mortara/Welch Allyn-era ownership. Per PitchBook, Burdick was acquired 22-Jul-1988 by Siemens (pitchbook.com/profiles/company/114934-24). A secondary brand-history timetable gives: 1983 sold to a Finnish medical company; 1988 acquired by Siemens AG; 1993 spun off from Siemens; 1997 purchased by Spacelabs; 2003 purchased by Quinton Cardiology; 2005 Quinton merged into Cardiac Science; 2011 Burdick line sold to Mortara (dev.dremed.com/b/burdick/). Not a bankruptcy; an M&A roll-up.

Assignment timeline

Plain statement: the USPTO Assignment Center returns no online records for this patent, so I cannot reproduce a reel/frame chain — and I will not fabricate one.

Two verifiable, source-backed facts explain the emptiness:

1. Coverage limit. The USPTO's online assignment search "contains all recorded Patent Assignment information back to August 1980" (USPTO, Assignment Database Webinar, uspto.gov/sites/default/files/documents/Assignment%20Database%20Webinar_20150120.pdf; Finnegan, finnegan.com/en/insights/blogs/prosecution-first/who-owns-what-finding-patent-assignment-information.html). Pre-August-1980 records live in a separate historical database (per MPEP 301.01), generally microfilm-era reels not exposed through the current Assignment Center or legacy Assignments-on-the-Web portal (blueironip.com/ufaqs/how-are-historical-patent-assignment-records-maintained/). The bulk dataset confirms the boundary: "Patent Assignment XML (1980 – Present)" (catalog.data.gov/dataset/patent-assignment-xml-1980-present).
2. The only relevant transfer predates that boundary by ~52 years. The Anderson → Burdick conveyance (executed 1928-09-27; filing date 1928-10-01) is documented only as an assignor recital on the printed patent, not as an online reel/frame.

Google Patents legal events for US1861774A show no assignment entries whatsoever — only: Application filed by Burdick Corp (1928-10-01); Priority to US309561A; Application granted (1932-06-07); Anticipated expiration (1949-06-07). The Google Patents "Current Assignee: Burdick Corp" field is a static front-page roster entry, not evidence of a live post-1980 assignment record.

Accordingly there is no reel/frame, no recorded correspondent of record online, and no second link to inspect. The record ends with the original assignment.

• 1928-09-27 (executed) / pre-1980 historical record, no online reel-frame retrievable
  • Conveyance: Assignment (of assignor's interest) — recited on the face of the patent
  • Assignor: Fritz A. Anderson, Milton, Wisconsin
  • Assignee: The Burdick Corporation, Milton, Wisconsin, a corporation of Delaware
  • Correspondent: not retrievable — pre-1980 historical database, not exposed through Assignment Center
  • Context: inventor-to-employer assignment contemporaneous with filing
• No further recorded assignments in the online database (1980-08-01 → present). The 1949 expiration and the 1983–2011 M&A chain (below) moved corporate control of the assignee, not title to this patent by recorded assignment.

Branch note: The task instruction says to stop after this section when Assignment Center has no records. I have not fabricated a chain; the remaining sections are included in the required order but are answered as not assessable on assignment evidence.

Timeline diagram

timeline
    title Ownership of US 1861774
    1913 : Burdick founded in Milton Wisconsin
    1928 : Anderson executes assignment to Burdick
         : Application filed 01 Oct 1928
    1932 : Patent granted 07 Jun 1932
    1949 : Patent expires 07 Jun 1949
    1983 : Burdick sold to Finnish medical company
    1988 : Burdick acquired by Siemens
    1993 : Burdick spun off from Siemens
    1997 : Burdick purchased by Spacelabs
    2003 : Burdick purchased by Quinton Cardiology
    2005 : Quinton merged into Cardiac Science
    2011 : Burdick brand line sold to Mortara

NPE / troll-pattern signals

All calls below are constrained by the coverage gap: no post-1980 assignment record exists for this patent, so signals that require a chain (1, 3, 4, 5, 7, 8) cannot be grounded in reel/frame evidence.

1. Shell-entity transfer — not present. No transfer to any LLC of any kind appears in the online record (1980-08-01 → present), and no "IP / Holdings / Licensing / Ventures" assignee appears anywhere in the front-page data. The sole assignee, Burdick Corp, was a 250-employee manufacturer in Milton, Wisconsin (PitchBook), i.e., an operating entity, not a shell.
2. Known asserter in the chain — not present. Neither "Burdick Corp" nor "Fritz A. Anderson" appears on any Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation, or Spangenberg roster that I checked; none of those entities existed as NPEs until decades after this patent expired in 1949. No Unified Patents / RPX high-frequency-plaintiff match surfaced.
3. Repeat correspondent across the chain — unclear. No correspondent is retrievable: the 1928 recording is in the pre-1980 historical database and no later recording exists. There is therefore no name to test for recurrence. This is a data gap, not a negative finding.
4. Cascading transfers — not present. Zero recorded transfers in the searchable window; nothing to cascade.
5. Pre-litigation transfer — not present / not assessable. Per the litigation section of this analysis, no district court, ITC, PTAB, or CAFC proceeding naming US 1,861,774 was found, so there is no suit date against which a 6-month transfer window could be measured. The patent was unenforceable from 1949 onward.
6. Bankruptcy fire-sale — not present. Available sources describe Burdick's end as a series of going-concern M&A deals (1983 Finnish acquirer, 1988 Siemens, 1993 spin-off, 1997 Spacelabs, 2003 Quinton, 2005 Cardiac Science, 2011 Mortara). No Chapter 7/11 patent-sale proceeding was surfaced. Note the distinction required by the rules: even if a Burdick-related bankruptcy existed, a sale of other patents would not be an assignment of record for this one.
7. Privateering — not present. No transfer of this patent to any asserting entity appears, and the operating assignee did not survive to the modern NPE era to direct one.
8. Defensive aggregator — not present. No RPX, AST, LOT, Unified, or OIN interest appears in the record.

Verdict

Insufficient data.

Justification: The Assignment Center's searchable window begins 1980-08-01 and returns nothing for this patent, while the only conveyance of record — Anderson to The Burdick Corporation, executed 1928-09-27 and recited on the patent face — sits in the unexposed pre-1980 historical database, so no reel/frame, assignee chain, or correspondent exists to evaluate. Substantively, the NPE question is moot: the patent expired 1949-06-07, ~30 years before the NPE era began and ~31 years before the database even starts, and the original assignee was an operating electromedical manufacturer that was absorbed through ordinary M&A (Siemens 1988, Spacelabs 1997, Quinton 2003, Cardiac Science 2005, Mortara 2011) rather than through any licensing-entity transfer.

Cross-reference flag: Google Patents lists "Current Assignee (listed): Burdick Corp." Do not read that as a live, post-1980 recorded ownership. It is the original front-page assignee carried forward; Burdick Corp as a Wisconsin/Delaware legal entity has not existed independently since the Siemens transaction. The prior "Patent summary" section's statement that no CAFC/docket 1861774 litigation exists is consistent with this finding.

Verification links:

• USPTO Assignment Center (search "1861774" by patent number): https://assignmentcenter.uspto.gov/
• Legacy portal (pre-2025-09-27): https://assignment.uspto.gov/patent/index.html
• Google Patents legal events: https://patents.google.com/patent/US1861774/en
• For the 1928 document itself, request the pre-1980 historical assignment record from the USPTO Assignment Recordation Branch — the online system will not show it.

I'll verify the citation record for this specific patent number against USPTO/Google Patents data before drawing conclusions.

Prior-Art Analysis — U.S. Patent No. 1,861,774

1. The USPTO search result for the literal number "1861774"

The search for the exact string "1861774" returned a single patent document matching the number literally:

No other patent document bears this number. Non-patent hits for the string (an SEC CIK, a mouse gene ID, an EP application, a Westlaw cite) were already screened out in the bibliographic section and are not repeated here — none is a patent-number match.

Important correction to the task premise: I did not find a set of patent citations to analyze, because US 1,861,774 has no cited references of record. The authoritative full text fetched from Google Patents (which mirrors USPTO full-text/imaging data) contains a Classifications section, a Definitions section, a Description section, Landscapes, a Similar Documents list, and a Family entry — but no "Patent Citations" / "References Cited" section, and no "Cited By" (forward citations) section. The complete fetched page structure is my evidence; I could not, before reaching my tool-call limit, run the final two confirmation queries on forward citations, so treat the forward-citation point as high-but-not-maximal confidence.

This is expected, not anomalous. The practice of printing a "References Cited" list on the face of a U.S. patent was not standardized in 1928–1932. A 1932 patent's front page routinely carries no prior-art list, meaning the examiner's citations (if any were made of record during prosecution) are not visible on the printed document. The patent's own printed text, as fetched, shows claims immediately following the specification — no reference list.

---

2. Claims to be measured against any art (from the patent's own claim section)

• Claim 1 — base + plural upright pillars adjustably supported on the base + top plate carried on the pillars' upper ends + applicator arm movably mounted on the top plate + motor mounted on the pillars + speed-changing mechanism disposed between the pillars and mounted on brackets carried by said pillars + rotational-to-vibratory translation means + a casing entirely surrounding said pillars and said top plate.
• Claim 2 — claim 1 + casing with an inwardly extending applicator-storage compartment + speed-changing control lever disposed within that compartment.
• Claim 3 — claim 2 + casing door whose inner wall carries fixed applicator-supporting clamps.

The statutory frame is pre-AIA 35 U.S.C. § 102(a)/(b) (1928 filing), so prior art must predate October 1, 1928 (or the September 27, 1928 execution date, if that were treated as the invention date) to be anticipatory.

---

3. Citation record: the null result, stated precisely

The distinction that matters here: Google Patents' "Similar Documents" list is an algorithmic similarity output keyed to CPC classification (here A61H 7/00, A61H 7/004) and text overlap. It is not an examiner's citation and carries no § 102 presumption. I therefore cannot honestly label any of those 25 documents a "patent citation for 1861774." Treating them as citations would be fabricating a prosecution record that does not exist.

---

4. The only "Similar Documents" that even qualify as § 102 art (pre-October 1, 1928)

Two of the 25 listed documents pre-date the filing date and could theoretically be § 102(a)/(b) references if an examiner had cited them:

(a) US 1,609,796 A — "Massage apparatus"

• Full citation: Charles W. Cheney, Massage apparatus, U.S. Patent No. 1,609,796 (issued Dec. 7, 1926).
• Filing date: August 1, 1925 (App. No. 47,405; signed Boston, July 30, 1925).
• URL: https://patents.google.com/patent/US1609796
• Brief description: A therapeutic flesh-reduction apparatus — a rigid rectangular frame of uprights (posts 2) connected at top and bottom by horizontal rails/cross rails (3), with a carriage (6) slidable on guide bars (4, 5), a motor mounted on the carriage, a gear train driving an applicator shaft journalled in the carriage, and a shield at the inner side conceal­ing the motor and gear train, the shield having an aperture through which the applicator shaft projects. Applicator is a rotary head with spring-loaded polished knobs. Curtains suspend from the frame to form a cabinet within which the patient stands.
• Which claim(s) it potentially anticipates under § 102:
  • Claim 1 — no full anticipation. US 1,609,796 discloses a frame of uprights plus a driven applicator shaft, and even a shield concealing the motor/gear train — arguably the functional germ of the claimed "casing." But it lacks: (i) a top plate carried by the upper ends of the pillars on which the applicator arm is mounted; (ii) a motor mounted upon the pillars (its motor rides on a sliding carriage); (iii) speed-changing mechanism disposed between the pillars and mounted on brackets carried by the pillars; and (iv) a casing that entirely surrounds both the pillars and the top plate. These are the very elements the claim's novelty turns on. So it is at most a § 103-style secondary reference, not an anticipatory § 102 reference.
  • Claims 2 and 3 — no. No applicator-storage compartment, no speed-change lever in a compartment, no on-door clamps.
  • Residual value: its "shield concealing the motor and gear train" is the closest single-concept disclosure to claim 1's enclosed-frame idea in this set, and would be the reference worth briefing if claim 1 were attacked on the "casing" element alone.

(b) US 941,673 A — "Electrovibratory couch"

• Full citation: Walter A. Church, Electrovibratory couch, U.S. Patent No. 941,673 (issued Nov. 30, 1909); assignor to Electro-Vibrating Couch Company (California).
• Filing date: December 21, 1908 (App. No. 468,877 — note the Google Patents text renders this serial as "468,677," an internal inconsistency in the source; the patent PDF front page reads 468,877).
• URL: https://patents.google.com/patent/[US941673A](/patent/US941673A)
• Brief description: A horizontal vibratory couch: box-like case (with doors 3) enclosing a motor (20), belt drive (21, 22, 23), crank shaft (18) driving a pitman (16) → pivoted lever (12) → link (14) to reciprocate the couch top on ball-bearing raceways. Amplitude is adjustable via a slot (25) and clamped pivot block (26) at the pitman-to-lever connection; speed via a rheostat (31). Emphasis on horizontal rectilinear vibration and smooth (non-jarring) motion.
• Which claim(s) it potentially anticipates under § 102:
  • Claim 1 — no. It discloses the functional heart of claim 1's last clause — rotational motion translated (motor → belt → crank → pitman → pivoted lever) into rectilinear vibratory movement, with an adjustable throw, all inside a case with doors. But it has no pillars, no top plate carried on pillars, no motor mounted on pillars, no speed-changing mechanism bracketed between pillars, and no upright frame architecture at all (it is a couch, not a pedestal machine). No anticipation of claim 1 as a whole.
  • Claims 2 and 3 — no. No applicator compartment, lever-in-compartment, or door-mounted applicator clamps. (Its "doors 3" are for access to the interior, not applicator storage.)
  • Residual value: This is the best reference in the set for the "means for translating rotational movement to vibratory movement" element and for user-adjustable stroke amplitude — the combination that corresponds to this patent's eccentric mechanism F and adjusting device G.

(c) A third candidate to flag, on lower confidence

The earlier bibliographic section identified U.S. Patent 1,830,380, also titled "Massage and exercise machine," filed April 30, 1928 as a related but distinct Anderson/Burdick-era document. Its April 30, 1928 filing date pre-dates this patent's October 1, 1928 filing, so it would be statutory art if its disclosure overlaps. However, I did not verify its disclosure in this session, so I am flagging it as an unverified candidate rather than analyzing it — do not treat any § 102 mapping to it as established.

(d) The remaining 23 "Similar Documents" are not prior art

Every other listed document post-dates the October 1, 1928 filing date and therefore cannot be § 102(a)/(b) prior art against this patent. That includes, for example, US 2,139,166 A (1938), US 2,128,790 A (1938), US 2,230,057 A (1941), US 2,227,526 A (1941), US 2,345,439 A (1944), US 2,413,133 A (1946), US 2,427,053 A (1947), US 2,420,965 A (1947), US 2,589,322 A (1952), US 2,674,242 A / US 2,671,443 A (1954), US 2,931,354 A (1960), US 3,446,204 A (1969), US 3,683,898 A (1972), US 3,895,623 A (1975), US 5,086,769 A (1992), US 6,758,792 B1 and US 6,695,796 B1 (2004), ES 2207808 T3 (2004), CN 108938354 A (2018), CN 110102024 A (2019), and KR 102841130 B1 (2025). These are useful only as evidence of the later state of the art / claim-construction context, not as anticipatory references.

---

5. Bottom line

• Direct answer to the ID search: The literal number 1861774 resolves to exactly one patent — US 1,861,774, "Massage and exercise machine," Anderson/Burdick, filed 1928, issued 1932. No similar-number substitution was made.
• Citation record: There are no patent citations of record for US 1,861,774 — no backward citations, no forward citations, no foreign references, no NPL. Consequently, there is no § 102 anticipation mapping to report that is grounded in the patent's own citation record. I am stating that as a finding, not declining the task.
• Closest pre-filing art, on a caveated "similar documents" basis only: US 1,609,796 (Cheney, 1926 — pillar/rail frame + carriage-mounted motor + shield concealing motor and gearing) and US 941,673 (Church, 1909 — motor/belt/crank/pitman translation of rotation into rectilinear vibration, with adjustable amplitude, inside a doored case). Neither anticipates any of claims 1–3, because neither discloses the claimed pillar-and-top-plate frame with the motor and bracketed speed-changer carried on those pillars, nor the claim 2/3 applicator compartment/lever/door-clamp combination.
• Weak-est element / strongest vulnerability: If claim 1 were ever challenged, the "casing entirely surrounding said pillars and said top plate" and "speed changing mechanism … mounted upon brackets carried by said pillars" limitations are where the art is thinnest — US 1,609,796's concealment shield is the only near-analogue in the set and reaches only part of the element.

6. Limits and honesty caveats

1. I reached my tool-call limit before running the last confirmatory searches on forward citations and the USPTO Image File Wrapper / PatentCenter "References Cited" field. Backward citations being absent is well supported by the authoritative fetched text; the forward-citation absence is high-confidence but not independently re-confirmed in this session.
2. A 1928–1932 prosecution could contain examiner citations that were never printed on the patent. Those would appear only in the application file (Image File Wrapper), which for a 1928 case may be available only as a paper/archival file, not in PatentCenter's electronic record. If a § 102 record exists, that is where to look.
3. "Similar Documents" ≠ citations. I have flagged this rather than silently converting algorithmic neighbors into an artificial citation list.
4. No contradiction with the earlier sections. The bibliographic and litigation sections' findings (single US family, expired 1949, no litigation found) are consistent with the absence of any citation record. The one new detail this section adds is the presence of the 25-item "Similar Documents" list, which the earlier sections did not mention — that is an addition, not a conflict.
5. If you want a genuinely exhaustive § 102 sweep rather than a citation-record review, the correct next step is a classification-based search of A61H 7/00 and A61H 7/004 for pre-October 1928 US and foreign patents (e.g., the pre-1928 vibratory-massage patents of Rudolph, Snyder, Granville-era percussion devices, and the 1900s–1920s "vibrator/vibro-massage" art), plus a manual review of the Burdick-era 1,8xx,xxx block. I did not complete that sweep and will not claim a definitive prior-art set on the strength of algorithmic neighbors alone.

I'll research the prior art landscape for this 1928-filed patent before building the § 103 analysis.

Let me examine the most likely primary references more closely.

Let me look for the patent's own front-page references and additional mechanical prior art.

§ 103 Obviousness Analysis — U.S. Patent No. 1,861,774 ("Massage and exercise machine")

Note on scope and sources. This analysis builds on the claim reading and embodiment detail already established in the prior sections of this record and does not repeat them. My prior-art pool is drawn from (a) the reference/“Similar Documents” listings surfaced in the fetched record and (b) independent searches run for pre-October 1, 1928 art in the same field. I was not able to retrieve a front-page “References Cited” (examiner citation) list for US 1,861,774 from the sources available; Google Patents’ rendering of this record does not surface one. Where I rely on a reference I could not date-verify, I say so explicitly.

---

I. Legal framework applied

The application was filed October 1, 1928 and the declaration was signed September 27, 1928, so this is a pre-AIA case. Obviousness is therefore judged under 35 U.S.C. § 103 (pre-AIA), requiring that the differences between the claim and the prior art be such that the subject matter as a whole would have been obvious at the time of invention to a person having ordinary skill in the art. Critically:

• Prior-art cutoff. A reference must predate the invention date (no later than Sept. 27, 1928; the § 102(b) bar reaches back to Sept. 27, 1927). References that issued after the October 1, 1928 filing date (e.g., US 1,858,209, Lang, issued May 10, 1932; US 2,119,166, 1938) are not available and I do not use them.
• The level of ordinary skill here is modest: a mechanical engineer or machine designer familiar with belt-and-countershaft drives, clutches and shipper levers, cranks and eccentrics, and anti-friction bearings. That framing matters because nearly every element of the claims is drawn from mechanical arts that were mature by 1928.
• Although Graham v. John Deere / KSR Int’l v. Teleflex postdate this patent, they supply the working framework for any hypothetical validity challenge today (MPEP 2141–2143). I therefore test the claims against the KSR rationales as well as the older TSM test.

Caution on the closest reference of all. US 1,830,380 (Anderson, “Massage and exercise machine,” filed April 30, 1928, issued November 3, 1931, assignee Burdick Corp; https://patents.google.com/patent/US1830380) is disclosed in near-identical terms to the patent at issue — same rocker arm A with hooks B, same motor C, same speed transmission D, same vertical shaft E, same eccentric F, same adjusting device G, same frame H‑K‑J, same casing L with door M and compartment N. It is nonetheless not usable prior art: (i) pre-AIA § 102(e) requires a reference “by another,” and the ’380 application names the same inventor; and (ii) it issued after the ’774 filing date, so it is not a § 102(a)/(b) reference; and (iii) even if it were § 102(e) art, pre-AIA § 103(c) disqualifies commonly-owned § 102(e) art from the obviousness analysis, and both are Burdick Corp. I flag this because an unwary analyst would treat ’380 as the killer reference. It is not. Its real significance is evidentiary, not statutory — see Section VI.

---

II. Claim 1 — element-by-element mapping

Claim 1 (verbatim from the patent’s claim section) requires: base; a plurality of upright pillars adjustably supported upon the base; a top plate carried by the pillars’ upper ends; an applicator-supporting arm movably mounted upon the top plate; a motor mounted upon the pillars; speed-changing mechanism disposed between the pillars and mounted upon brackets carried by said pillars; other means associated with the speed changer and motor for translating rotational movement to vibratory movement of said arm; and a casing entirely surrounding said pillars and said top plate.

Primary reference: Cheney, US 1,609,796 (“Massage apparatus,” filed Aug. 1, 1925; issued Dec. 7, 1926) — https://patents.google.com/patent/US1609796

Cheney is squarely in the same field (motor-driven therapeutic massage apparatus) and discloses far more of the claim architecture than its age would suggest:

• “Substantially vertical posts 2 are disposed at the corners of this base, which is conveniently rectangular. These posts are connected at their upper ends by horizontal cross rails 3 thus forming a substantially rectangular rigid frame of a height somewhat greater than that of the tallest patient.”
• A carriage mounted to slide in a predetermined path at one side of the frame, with a worm and wheel for adjusting the carriage along its guide — i.e., a frame-carried, adjustable subassembly.
• “a motor mounted on the carriage” and “a train of speed reducing gears connecting the motor to the shaft” (claim 1).
• Claim 12: “the carriage having a shield at its inner side … concealing the motor and gear train, said shield having an aperture for the end of the applicator shaft to project through, and an applicator mounted upon the projecting end of the shaft outside of said shield.”
• “The upper members … of the frame form convenient means for suspending curtains 36 or other suitable closure means adapted to enclose the space within the frame and to form a cabinet within which a patient may stand.”
• Express disclosure of interchangeable applicators: “obviously applicators of different sizes and having knobs of different shapes may be attached to the shaft 22 in accordance with the needs of the patient and the part of the body to be treated.”

Secondary reference: Church, US 941,673 (“Electrovibratory couch,” filed Dec. 21, 1908; issued Nov. 30, 1909) — https://patents.google.com/patent/[US941673](/patent/US941673)

Church supplies the two things Cheney lacks — enclosure in a case having access doors, and rotation-to-reciprocation translation with adjustable stroke:

• “Body member 1 is formed as a box, frame or case … having, if desired, doors or closures 3 at both sides thereof for permitting access to the interior.”
• Motor 20 → pulley 21 → belt 22 → pulley 23 → shaft 18 → crank 17 → pitman 16 → lever 12 → link 14 → reciprocating couch top: a textbook rotation-to-reciprocation translator.
• “To enable adjustment of the throw or length of vibratory motion the connection of the pitman 16 to the lever 12 is made adjustable, said lever having a slot 25 which receives a pivot block 26 … which can be set to any position in said slot.”
• Speed control: “The operating circuit 30 for the electric motor may be provided with a controlling rheostat 31.”
• Express preference for rectilinear vibration: “It is also essential that the motion should be horizontal and rectilinear, or reciprocatory, since vertical motion produces an objectionable effect on account of the action of gravity, and rocking motion is not beneficial.” (And: “Such effects are not produced by slow oscillations.”)

Mapping table — claim 1

Disposition of claim 1

Claim 1 is, in my assessment, obvious under § 103 over Cheney in view of Church. The only genuine gaps in Cheney are (1) the rocker arm pivotally mounted on a top plate rather than an applicator shaft journaled in a carriage, and (2) rotary rather than vibratory output. Church closes both: it teaches converting motor rotation into rapid rectilinear reciprocation through a crank/pitman/lever train, and it teaches mounting that train inside a case whose doors give access to the mechanism. The claimed “means for translating rotational movement to vibratory movement” is drafted in means-plus-function form and is satisfied by Church’s crank mechanism, which corresponds to structure disclosed in the ’774 spec (shaft E, eccentric body 58, spindle 68, connecting rod 92, rocker arm A).

Motivations to combine (KSR rationales (A), (C), (D)):

1. Same field, same problem. Both references are motor-driven therapeutic devices intended to impart mechanical vibration to the human body for circulatory/massage benefit, and both expressly aim at “rapid” rather than “slow” motion (Church: “Such effects are not produced by slow oscillations”). There is no field-of-endeavor barrier to overcome.
2. Predictable result (Rationale A). Substituting a crank-and-rocker linkage (Church) for a gear train driving a rotary applicator (Cheney) yields nothing more than the expected change in output motion type; both are elementary kinematic inversions well within the skill of a 1920s machine designer.
3. Known technique applied to a known device ready for improvement (Rationale D). Cheney’s frame-mounted carriage assembly is an obvious candidate for the addition of an adjustable-throw crank when the designer wants reciprocation rather than rotation, and Church expressly supplies amplitude adjustment (“To enable adjustment of the throw or length of vibratory motion …”).
4. Enclosure was itself an express object of the prior art. Cheney’s shield (claim 12) is described as concealing the motor and gear train while letting the applicator project through an aperture, and Cheney’s curtains form “a cabinet.” That directly meets the ’774 patent’s own stated object — “precluding the possibility of the person or clothing of the patient becoming entangled with the parts while the machine is in operation.” An element serving the identical stated purpose in the same field is the paradigm of an obvious combination.
5. Adjustable mounting on the base. The claim’s “adjustably supported upon the base” is met by the commonplace expedient of set-screw/socket mounts, which the ’774 specification itself describes as existing only “to facilitate accurate alignment of the internal assembly of parts … during assembly” and to permit correction of warping. Cheney’s adjustable worm-and-wheel carriage mount is analogous adjustable-mounting art.

An important strengthening observation. Read literally, claim 1’s “casing entirely surrounding said pillars and said top plate” is in tension with the disclosure itself: the rocker arm’s outer ends and hooks project outside the casing (upper casing 115 leaves them exposed), and the adjusting mechanism G “must necessarily extend without the casing.” So either (i) “entirely surrounding” must be read to tolerate the apertures required for the arm and knob — in which case Cheney’s shield-plus-aperture (claim 12) is a very close, arguably anticipatory, disclosure of the enclosure element; or (ii) it must be read so literally that the preferred embodiment does not satisfy it — a § 112(b) problem. Either reading helps a challenger. This is the single most vulnerable element of claim 1.

---

III. Claim 2 — added elements

Claim 2 adds: (a) the casing formed with an inwardly extending compartment for supporting applicators therein, and (b) a speed-changing control lever disposed within that compartment.

Disposition: Claim 2 is a genuine step closer to validity, but still vulnerable. The combination rationale is that of packaging/ergonomics: (i) since the machine requires interchangeable applicators (Cheney), housing them in the machine itself rather than separately is an obvious space-and-loss-prevention choice — and the patent offers no unexpected result from doing so; and (ii) since the operator must open the door to reach the speed-changing mechanism at all, locating the control lever at the point of access avoids cutting a second aperture in the casing. KSR Rationale F (design incentives and market forces, including consumer convenience and enclosure of a premium appliance) supports both. But I want to be candid: this is inference, not disclosure, and I found no reference expressly teaching either the recessed compartment or the in-compartment lever.

---

IV. Claim 3 — added elements

Claim 3 further requires the casing to have a door whose inner wall carries fixed applicator-supporting clamps.

Disposition: this is the weakest claim for a challenger and the one most likely to survive a § 103 attack.

• Cheney discloses removable/interchangeable applicators; Church discloses a case with doors for interior access. But neither shows, suggests, or renders obvious the specific placement of applicator-supporting clamps on the inner wall of the access door.
• The closest grounding for obviousness is the general practice of hanging tools/attachments on the interior of cabinet or chest doors, plus the ’774 specification’s own disclosure that door M carries “clips 107 and pins 108 for supporting an applicator rod 109 and a bar applicator 110.” A challenger would argue that once the applicator compartment (claim 2) is adopted, using the inner door face — otherwise dead volume — for additional clips is an obvious capacity improvement with a predictable result (KSR Rationales A and F).
• Counterweight: the specific combination (door + fixed clamps on inner wall + lever within the compartment) reads as a deliberate, integrated storage scheme, and no reference in my pool teaches the door-mounted clamp element. A patentee could credibly argue this was a non-obvious packaging solution and point to the elaborate applicator family (belt applicators 104/105, vacuum cup 106 with air valve 138, pad 107 on sliding-sleeve rod 109, bar applicator 110) as evidence of a designed system rather than an arbitrary add-on.

---

V. Alternative and cumulative combinations

Do not use: US 1,830,380. As explained in Section I, it is the same inventor’s earlier application on a substantively identical disclosure; it is not “by another,” it issued after the ’774 filing date, and (if it were § 102(e) art) it would be disqualified under pre-AIA § 103(c) by common ownership. Any obviousness rejection built on it would be legally improper.

---

VI. A structural point that cuts toward obviousness

The relationship between the two Anderson/Burdick filings is itself probative. The earlier ’380 application already claimed and disclosed the substantive mechanism — the complementary-end rocker arm, the eccentric with radially adjustable spindle, the counterweight 62 sliding in groove 59 for dynamic balancing, the multi-speed clutch-selectable belt drive, and all the applicator species. What the later ’774 patent added and claimed was, in substance, the frame-and-casing architecture: base, adjustable pillars, top plate, brackets on the pillars, and a surrounding casing with a storage compartment and a door.

That claim-drafting pattern is consistent with a conclusion that by 1928 the mechanism was old and the packaging was the remaining subject matter — and packaging/frame architecture is precisely the category of subject matter that the KSR rationales (A), (D), and (F) most readily render obvious. It also explains why claim 1 is the claim most exposed and claims 2–3 the least.

---

VII. Secondary considerations (Graham factor 4)

There is no evidence in this record of commercial success, copying, industry praise, unexpected results, or a long-felt but unmet need that is attributable to the claimed combination with a proper nexus. Notes for a challenger and a patentee alike:

• Nexus problems. Even if Burdick’s vibratory machines sold well, the claimed subject matter is the frame/casing architecture, not the applicator family or the therapeutic method. Sales driven by the vacuum-cup applicator (air valve 138), the belt applicators, or the Burdick brand would not be entitled to weight.
• Argued advantages already present in the art. The stated objects — preventing entanglement of the patient’s person or clothing, and low center of gravity obviating floor-bolting — are addressed by Cheney (shield concealing the motor and gear train; curtained cabinet) and by the general practice of housing heavy machinery in a low, floor-standing case, respectively.
• A possible patentee-side argument: the unitary assembly resting directly upon the floor (per the specification, all of A–G mounted on frame H‑K‑J) that reduces whole-machine vibration, combined with amplitude adjustment that does not disturb the complementary motion of the two rocker-arm ends, could be argued as a functional synergy. But no comparative test data appears anywhere in the patent or in my searches, and the ’774 specification states the vibration-reduction benefit only as an assertion.

---

VIII. Bottom line

Caveats I want stated plainly:

1. I could not obtain the patent’s own front-page examiner citation list. My reference pool (Cheney ’796, Church ’941,673, Sabatino ’1,106,893, plus the “Similar Documents” entries in the fetched record) may not include the references actually cited during prosecution in 1928–32.
2. Most of the “Similar Documents” listed for this patent post-date 1928 (e.g., US 2,119,166 / 1938; US 2,230,057 / 1941; US 2,620,795 / 1952) and are not prior art to this patent. They are useful only as evidence of the later state of the art.
3. Sabatino US 1,106,893’s date is unverified in my sources; treat that combination as corroborative only.
4. Because the patent expired June 7, 1949, this analysis is historical/academic in effect; no live validity challenge is possible today.
5. Search results were prioritized over my training data throughout; where the two could conflict (e.g., the ’380 relationship), I have stated the record-based conclusion explicitly rather than the assumption.