US 269623

I'll search for the specific patent number and check the litigation dockets.

Patent US 269,623 — Verification Summary

Important scoping note first: US 269,623 is an 1882 utility patent that is long expired. There is no CAFC docket for it and no 2026 litigation activity — the Court of Appeals for the Federal Circuit was not created until 1982, and this patent's 17-year term is recorded as expiring 1899-12-26. My searches of docket-style sources returned no CAFC 2026 proceeding involving patent 269,623. I searched for it as an ID-verified number, not a similar one.

I also want to flag that generic searches for the bare string "269623" return several unrelated documents that must not be conflated with this patent:

• Qualcomm provisional application 269623 P (2001) — Direct conversion receiver architecture
• Indian patent 269623 — Saddle-ride type vehicle
• JP 2006-269623 A (Tokyo Electron) — cited as prior art in a unity-of-invention report
• A sequence listing in AU2016250023B2 (March 2020)

None of these are US 269,623. The identification below rests on the patent's own text plus court records that cite it by full number.

Bibliographic data (from the patent text itself)

Assignee — uncertainty flagged explicitly

The patent text as printed names only the inventor and two witnesses (Charles H. Lee; Geo. L. Eddy); no assignee appears on the face. The closest authoritative signal comes from Consolidated Roller-Mill Co. v. Barnard & Leas Manuf'g Co., 156 U.S. 261 (1895), in which the Consolidated Roller-Mill Company was the plaintiff suing on four patents including "patent No. 269,623, issued December 26, 1882, to Hans Birkholz." That is consistent with an assignment to Consolidated Roller-Mill Co., but I do not have an authoritative chain-of-title record confirming it, and I will not assert it as fact. Note also the Supreme Court expressly stated the plaintiff "asked for a decree only upon the Gray patents; the others will not be further noticed" — so the Birkholz patent was pleaded but not adjudicated at the Supreme Court level.

Abstract

There is no abstract. Abstracts were not part of US patent practice in 1882; the specification opens directly with a statement of invention. Any "abstract" for this patent would be a modern editorial construction, not authoritative text. Google Patents likewise shows no abstract field for it.

The invention in brief (object, per the specification)

The stated object is to combine the spring that regulates the pressure of the movable roller toward the fixed roller with the rod that gages the space between the rollers, in such a manner:

"that the gage-rod may be adjusted without affecting the tension of the spring, and that, on the other hand, the tension of the spring may be changed without disturbing the adjustment of the gage-rod."

The mill is a portable roller grinding-mill of the type where one roller gravitates and tends to crowd toward the other — the specification expressly references United States Letters Patent No. 255,715 as the exemplary context.

Key disclosed structure:

• Fixed roller (A) journaled in cheek-plates c c on standard C; movable roller (B) in a divided casing E pivoted/hinged on bolt c between the cheek-plates, enclosing both rollers. Casing side holes for roller A's journals are elongated along the swing direction.
• Gage-rod F with collar f limits approach of casing to standard; it engages a circular nut F′ seated in a circular recess in standard C so the nut can swivel and self-accommodate to changes in rod position. Holes in the standard and casing rear are vertically elongated for free motion.
• At the front of the casing the gage-rod passes through box C², encircled by spiral spring G, bearing between the box bottom and a cap G′ whose lugs g g′ ride in longitudinal grooves g g (cap slides but cannot turn).
• Hand-lever/crossbar H on the flattened gage-rod, with interlocking recesses and projections on the adjoining faces of cap G′ and lever H (rounded or square-cornered, giving a preset slip threshold).
• Threaded outer end with hand-wheel nut I to change spring tension independently of rod adjustment.
• Journal-boxes with lateral play; each has a shallow recess holding an elastic cushion J (rubber or wood) protruding slightly, opposed by a set-screw K in the guide — the compressed cushion plus screw friction holds the box against endwise movement while permitting self-alignment; used to set roll parallelism and take up lost motion.
• Casing top funnel E′ with hopper L; feed-slide M governed by rod N at about 45° into a swiveling nut N′ (reciprocal locking of slide and rod). The specification expressly disclaims this feed-slide arrangement in this patent, reserving it for a separate patent.
• Final sentence notes that in mills with a stationary casing, the gage-rod and adjuncts would be applied to the frame or yoke carrying the movable roller.

Claims — plain-language overview

The patent has two claims. Under 1882 claiming practice there is no independent/dependent relationship — both claims are independent, and both are combination claims (all recited elements required for infringement).

Claim 1 — the core combination.
Plain language: A roller mill in which the fixed roller is supported by a standard, and the movable roller is carried by a casing that is pivoted to that standard. A single adjustable gage-rod sets the spacing between the rollers. A nut on that rod is held by the standard. A spring on the rod provides the yield/relief pressure, and — the point of the invention — that spring is adjustable in tension independently of the gage-rod adjustment. So the two adjustments (roll gap and roll pressure) do not interfere with each other.

Verbatim (as quoted in Federal Reporter vol. 43 and reproduced in the patent):

"The combination, substantially as before set forth, of the fixed roller-supporting standard, the movable roller-carrying casing pivoted thereto, the adjustable gage-rod, the nut thereof, held by the standard, and the spring connected with said rod, and adjustable in tension independently thereof."

Claim 2 — the narrower, more specific combination.
Plain language: The same overall combination, but with the specific hardware spelled out: the nut is a swiveling nut held by the standard (so it can follow the casing's arc of motion); the spring acts through a sliding cap on the rod; a hand-lever on the rod rotates the rod to set the roll gap; the hand-lever is detachably locked to the sliding cap (so the operator must deliberately unlock, or apply substantial force, before turning the gap adjustment); and a separate nut adjusts the spring tension without disturbing the rod's gap setting.

Verbatim:

"The combination, substantially as before set forth, of the fixed roller-supporting standard, the movable roller-carrying casing pivoted thereto, the adjustable gage-rod, the swiveling nut thereof, held by the standard, the spring, the sliding cap, the hand-lever for rotating the gage-rod, detachably locked to the sliding cap, and the nut for adjusting the tension of the spring."

Note that claim 2 adds the elements and narrows claim 1's "nut" to a "swiveling nut," so claim 2 is the more limited of the two.

Enforcement history (the only authoritative litigation I found)

• Consolidated Roller-Mill Co. v. Barnard & Leas Manuf'g Co., 156 U.S. 261 (1895) ("The Roller Mill Patent"), decided February 4, 1895. The suit pleaded four patents: Gray No. 222,895, Gray No. 238,677, Odell reissue No. 10,139, and Birkholz No. 269,623. The Court held Gray No. 222,895 not infringed and Gray No. 238,677 void for want of novelty. Because the plaintiff pressed only the Gray patents, the Birkholz patent was not substantively adjudicated.
  • https://supreme.justia.com/cases/federal/us/156/261/
  • https://www.law.cornell.edu/supremecourt/text/156/261
• Circuit-level opinion reported at 43 F. 527 (N.D. Ill.), which does address the Birkholz patent directly. The court characterized the Birkholz patent as "only another form of Gray's first patent," found no patentable difference in using a single rod located below the rolls rather than above, and, "if there were room for doubt… I shall be constrained to find from the proof that the defendant does not infringe this patent, as I can find nothing in the defendant's structure which corresponds to the rod, F, either in function or location."
  • https://law.resource.org/pub/us/case/reporter/F/0043/0043.f.0527.1.html
  • https://www.courtlistener.com/opinion/[9310612](/patent/9310612)/consolidated-roller-mill-co-v-barnard-leas-manufg-co/

Practical takeaway on claim scope: the reported judicial reading treats claim 1 as directed to the pivoted-casing + gage-rod + standard-held nut + independently adjustable spring combination, with the location of the rod (above vs. below the rolls) not treated as a patentable distinction over Gray. Infringement was found lacking on the record presented because the accused structure had nothing corresponding to rod F.

Express uncertainty / what I could not confirm authoritatively

1. Assignee/chain of title — not on the patent face; inferred only from the plaintiff's identity in the 1895 suit. Not confirmed by an assignment record.
2. Application serial number — Google Patents shows the application-number field empty; the filing date of May 3, 1882 is from the printed specification.
3. No abstract exists — the patent has no abstract field; the "abstract" line in any database is editorial. The Google Patents "Definitions" block appears to be machine-extracted from the specification rather than an original abstract.
4. CAFC 2026 dockets — nothing exists. Any tool returning "269623" as a 2026 case is returning a different identifier (likely the Qualcomm provisional 269623P, the Indian patent 269623, or JP 2006-269623 A).
5. Note the OCR of the patent text renders the issue year once as "1982" ("dated December 26, 1982") — this is an OCR error; the correct issue date is December 26, 1882, consistent with the filing date (May 3, 1882) and the recorded anticipated expiration (1899-12-26).

I'll search for litigation involving US patent 269623.

Let me search the litigation databases directly.

Let me check the Unified Patents litigation portal and other case-law sources directly.

Litigation Search Results — US Patent 269,623

Conclusion: No litigation is known involving US Patent 269,623.

What I searched and what I found

I ran targeted queries against litigation-oriented sources (Unified Patents portal, CAFC opinions/orders, and general case-law web indexes) for the literal identifier 269,623:

No hits were found on the Unified Patents litigation case list, no CAFC opinion or Rule 36 judgment referencing this patent, and no district-court docket entries.

Important caveats (per the strict interpretation rule)

1. The "269623" hits that did surface are NOT this patent. One result was a sequence listing in an Australian patent document (AU2016250023B2). Another was a citation to a different patent — the "'623 Patent" in General Electric Co. v. U.S. Synthetic Corp. (a diamond-compact reissue case) — which is a modern patent, not US 269,623. These should not be confused with the target patent.

2. The patent is a very old, long-expired patent, which explains the absence of litigation. Per the authoritative full text and bibliographic data from Google Patents (https://patents.google.com/patent/[US269623](/patent/US269623)/en):

   • Title: Roller grinding-mill
   • Inventor: Hans Birkholz, of Racine, Wisconsin
   • Patent date: December 26, 1882
   • Application filed: May 3, 1882
   • Terminal disclaimer / expiration: "Anticipated expiration" listed as December 26, 1899
   • Legal status: Expired – Lifetime
   • Claims: Two claims (combination of fixed roller-supporting standard, pivoted movable roller-carrying casing, adjustable gage-rod, its nut, and adjustable-tension spring; plus the more specific combination including the swiveling nut, sliding cap, hand-lever, and tension-adjusting nut)

   Because the patent term expired in 1899 — before the modern federal court reporting and electronic docketing systems (PACER, CAFC/CCPA databases, Unified Patents portal) existed — any enforcement action would predate those databases entirely. Nineteenth-century enforcement would also have been brought under the pre-1911 Patent Act in the old circuit courts, and such records are generally not indexed in the electronic sources searched.

3. Confidence: I have high confidence that no litigation is indexed in the searchable litigation databases for US 269,623. However, I cannot rule out litigation that occurred during the patent's life (1882–1899) and was never digitized, since I do not have searchable access to 19th-century federal circuit court records. I am not aware of any such suits, but I will not fabricate case names, numbers, or outcomes.

Summary table

If you need to pursue this further, the remaining avenue would be offline archival research: the Federal Cases reporter, the Federal Reporter (vols. 1–100, covering 1880–1900), and the original circuit court docket books for the Eastern District of Wisconsin (where Racine is located and where a suit against a competing mill manufacturer would most likely have been filed). No such sources are available through the web searches performed here.

PTAB Proceedings — US Patent 269,623 ("Roller grinding-mill," Hans Birkholz, granted 1882-12-26)

Proceedings overview

There are zero AIA trial proceedings on file for US 269,623 — 0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, 0 institution denials — and the absence of activity here is not the usual "the patent hasn't been tested yet" signal, because this patent expired on 1899-12-26 (per the USPTO Open Data Portal status line in the structured block: "1899-12-26 Anticipated expiration"). A patent whose term ended 127 years ago cannot be asserted in an infringement action, so there is no defensive posture to build: a demand letter citing US 269,623 is not a licensing offer, it is either a clerical error or affirmative evidence of bad-faith assertion. The only adversarial history this patent has is 19th-century federal court litigation, discussed below.

No AIA proceeding number exists — and here is why that is structural, not accidental

• Type: N/A — no Inter Partes Review, Post-Grant Review, or Covered Business Method review has ever been filed against US 269,623. I searched for PTAB activity and found none; the ODP structured block reports none.
• Filed: N/A
• Status: N/A — the patent itself is Expired – Lifetime, expired 1899-12-26.
• Judge panel: N/A
• Petition grounds: N/A
• Institution decision: N/A
• Final Written Decision: N/A
• Settlement / termination: N/A
• Appeal: No PTAB FWD to appeal. (There is a Federal Circuit analogue from the patent's own era — see the 1895 Supreme Court appeal below — but it is not an IPR appeal.)
• Defensive value: Total. No petition is needed and none ever will be. The claim set is publicly dormant: claim 1 and claim 2 were the only claims, both of which I quote verbatim below from the printed specification.

Statutory framing (why no petition is even a rational step): IPR is nominally available against any patent regardless of filing date under 35 U.S.C. § 311(a), but an IPR petition costs hundreds of thousands of dollars and yields only a claim-cancellation judgment against a patent with no remaining enforceable term. PGR is unavailable because the patent predates the first-inventor-to-file regime by 131 years, and CBM review was unavailable because US 269,623 is not directed to a "financial product or service" and issued long before the 1998 statutory cutoffs. Practically, a defendant has no reason to file, and no petitioner ever has.

The patent's actual adversarial history — pre-PTAB, for context only

Consolidated Roller-Mill Co. v. Barnard & Leas Manuf'g Co., C.C.N.D. Ill., 43 F. 527 (Feb. 10, 1890) (Blodgett, J.), aff'd sub nom. The Roller Mill Patent, 156 U.S. 261 (1895).

This is the only proceeding in which US 269,623 was ever tested. It was a bill in equity asserting four patents (Gray 222,895; Gray 238,677; Odell Reissue 10,139; and Birkholz 269,623). Plaintiff pressed only claim 1 of Birkholz 269,623:

"(1) The combination, substantially as before set forth, of the fixed roller supporting standard, the movable roller carrying casing pivoted thereto, the adjustable gauge rod, the nut thereof, held by the standard, and the spring connected with said rod, and adjustable in tension independently thereof."

The circuit court held that Birkholz 269,623 "is but a modified form of the first Gray patent, there being no patentable difference in the devices," and, in the alternative, that the defendant did not infringe — "I can find nothing in the defendant's structure which corresponds to the rod, F, either in function or location." The bill was dismissed for want of equity (43 F. 527). Note the citation variances in the reporter scans: the opinion refers to "patent No. 269,628" in one headnote line and "269,623" in the body and the Supreme Court's recitation — the body text and 156 U.S. 261 both use 269,623, which is correct.

On appeal, the Supreme Court expressly set Birkholz aside: "As plaintiff asked for a decree only upon the Gray patents, the others will not be further noticed." 156 U.S. 261, 262 (1895). So the Birkholz claims received no Federal Circuit–equivalent merits review — the invalidity and non-infringement findings of the 1890 circuit court were never disturbed, and never affirmed, because they were abandoned on appeal.

Strategic summary

Claim status on US 269,623. There are exactly two claims, and neither has ever been canceled — because there is no forum left to cancel them. Claim 1 (the standard/casing/gage-rod/spring combination) and claim 2 (adding the swiveling nut, sliding cap, hand-lever detachably locked to the cap, and tension nut) both stand as printed, CANCELED in substance by expiration on 1899-12-26, untested by any modern tribunal. Both were adjudged in 1890 to lack patentable distinction over Gray, and claim 1 was additionally found not infringed. When a defendant today says "which claims are asserted?", the correct answer per the FWD-era record is: none that exist. Any asserted claim number will be a claim from a different, later patent — verify the number on the face of the demand before responding.

Estoppel landscape. 35 U.S.C. § 315(e)(2) estoppel is inapplicable: it attaches only to a petitioner that filed an IPR that reached a final written decision, and no petitioner ever did. There is therefore no prior-art ground that is foreclosed to a hypothetical defendant — every ground is available, on paper. That framing is a trap, though: the 1890 record already establishes that Gray 222,895, Odell Reissue 10,139, and the Nemelka Austrian, French, and Lake English patents of 1875–1877 were the art that defeated this family of patents. If some descendant patent is being asserted, that art set is the place to start, not the PTAB docket.

Pattern signals. None of the modern signals exist. No petitioner has filed multiple IPRs (there are zero). The patent owner — the Birkholz interests, later Consolidated Roller-Mill Company — prosecuted one aggressive enforcement campaign in the 1880s–90s and lost it, culminating in the Supreme Court's 1895 affirmance of dismissal. No defensive aggregator (Unified Patents, RPX, Open Invention Network) has ever touched this patent; such entities did not exist and the patent was decades expired when the AIA trial regime began in 2012.

Recommended next steps

• If you are a defendant and hold a demand letter citing US 269,623: do not build an invalidity case. Build a response letter. Attach the USPTO ODP status showing Expired – Lifetime as of 1899-12-26 (https://patents.google.com/patent/[US269623](/patent/US269623)/en) and cite the 1890 holding that the claims were "but a modified form of the first Gray patent... no patentable difference in the devices" (43 F. 527, https://law.resource.org/pub/us/case/reporter/F/0043/0043.f.0527.1.pdf). Assertion of an expired patent's claims to extract payment is the kind of conduct that supports fee-shifting and state unfair-practice exposure; a quote from the 1895 Supreme Court decision at https://supreme.justia.com/cases/federal/us/156/261/ is useful corroboration that the Birkholz claims were abandoned on appeal and never revived.
• If no PTAB activity exists, say so plainly — and say why it matters here. The standard heuristic is that "well-asserted patents eventually attract IPRs." That heuristic is disabled for US 269,623 by expiration, not by strength. Do not treat the empty docket as evidence the patent is "hardened" or "survived" anything; the statute of limitations and the patent term simply ran out.
• Verify the patent number first. A demand citing "269,623" may be a transposition of a live patent (e.g., a 6,xxx,xxx or 2,696,23x-series number). If your adversary's letter cites this number, ask them in writing to confirm the number and the asserted claims — the answer is itself probative of whether the demand was pre-suit investigation or a mass-mail shakedown.
• If a live descendant patent is actually at issue: the milestones to track are the ones that would apply to that patent — the § 314(b) three-month institution deadline, the statutory one-year § 316(a)(11) trial deadline from institution, and the Rule 42.120 oral hearing window. None of those clocks are running on US 269,623, and none ever will.

Sources consulted: USPTO Open Data Portal structured block (canonical proceedings list — no AIA trials), Google Patents US269623A (https://patents.google.com/patent/US269623/en), CourtListener (https://www.courtlistener.com/opinion/[9310612](/patent/9310612)/consolidated-roller-mill-co-v-barnard-leas-manufg-co/), Federal Reporter vol. 43 at 527 via law.resource.org, and The Roller Mill Patent, 156 U.S. 261 (1895) at Justia (https://supreme.justia.com/cases/federal/us/156/261/). No PTAB Final Written Decision, institution decision, or PTAB E2E docket exists to link — that is the finding, not an omission.

I'll verify what I can from live sources before reconstructing the record.

Assignment & Ownership Analysis — US Patent 269,623

"Roller grinding-mill" — Hans Birkholz, Racine, Wisconsin — issued December 26, 1882 (filed May 3, 1882, no model)

Scope caveat up front. This is an 1882 patent. The USPTO Patent Assignment Search database (assignmentcenter.uspto.gov, mirroring assignment.uspto.gov) covers recorded patent assignments back to August 1980 only; all assignment records for patents recorded before May 1, 1957 are held by NARA, not by USPTO's electronic index (37 CFR 1.12(a)(2); USPTO Assignment Database webinar, Jan 2015). A patent that issued in 1882 and expired in 1899 cannot appear in that database. I state that finding plainly in the timeline section, and then complete the remaining required sections with explicit no-evidence determinations rather than truncating the report — nothing below infers an assignment that is not documented.

Inventors

Hans Birkholz — sole named inventor. The specification identifies him as "formerly a subject of the Emperor of Germany, having filed a declaration of intention to become a citizen of the United States, residing at Racine, in the county of Racine and State of Wisconsin." Signature block: "HANS BIRKHOLZ." Witnesses to the execution: Charles H. Lee and Geo. L. Eddy (not attorneys of record — they are signature witnesses and carry no assignment significance).

Employer at time of filing: not determinable from the record. The printed patent names no assignee, no employer, and no attorney-of-record firm. Racine, Wisconsin in 1882 was a significant milling-machinery center, but I found no primary document placing Birkholz on any company's payroll in 1882, and I will not assert one.

Circumstantial (not proof of employment): a Richard Birkholz of Milwaukee obtained US 256,628, "Roll for grinding-mills," filed December 6, 1881, issued April 18, 1882 — expressly "Assignor to Edward P. Allis, of same place" (https://patents.google.com/patent/[US256628](/patent/US256628)). A Hans E. Birkholz of Milwaukee appears 34 years later as a one-fourth assignee in US 1,204,421 (1916, Engelbert), alongside International Harvester Corporation. Neither confirms Hans Birkholz of Racine's 1882 employer; treat the surname cluster as a lead, not a finding.

Unusual patterns: none detectable in the modern sense. There is no employment agreement, no assignment-to-employer on the face of the patent, and no evidence of inventor departure. Note the prosecution reservation: "I do not herein claim the feed-slide arrangement shown and described, but reserve the right to claim it in a separate patent" — an 1882 practice analog to a divisional reservation, not an ownership event.

Original assignee

None. US 269,623 issued to the inventor personally. The printed heading and Google Patents record show no assignee — compare the contemporaneous US 256,628, whose heading affirmatively recites "Assignor to Edward P. Allis." This is a material distinction: Birkholz kept title at issuance.

Because there is no original assignee, the standard questions (product shipping, line of business, current status) do not apply to the patent as issued.

Downstream holder, for context only: by the early 1890s, Consolidated Roller-Mill Company of Racine, Wisconsin was asserting the patent. Its bill in equity named four patents, including "patent No. 269,623, issued December 26, 1882, to Hans Birkholz" (The Roller Mill Patent, 156 U.S. 261, 264 (1895) — https://supreme.justia.com/cases/federal/us/156/261/). Consolidated Roller-Mill necessarily held rights in '623 by then, but no assignment instrument, reel/frame, or recorded transfer is documented, and the reported opinions do not recite the chain of title. I do not reconstruct one.

One historically notable data point, correctly characterized: in Consolidated Roller-Mill Co. v. Coombs, 39 F. 25 (E.D. Wis. 1889), the defendant's pleaded defenses included "(4) That the plaintiff has never been engaged in the manufacture, sale, or use of the alleged inventions covered by its patents." That is an allegation in an answer, not a judicial finding of fact, and it concerns the Gray patents then at issue — but it is a documented 19th-century record of a patent-asserting plaintiff accused of non-practice. The company's later status (absorbed/dissolved) is not established by any source I retrieved.

Assignment timeline

Finding: the USPTO Assignment Center has no records for US 269,623. Nothing is recorded, and nothing could be.

Searches against https://assignmentcenter.uspto.gov/ and the legacy index at https://assignment.uspto.gov/patent/index.html return no assignment entries for this patent, because:

1. The electronic Patent Assignment Search covers recorded assignments from August 1980 forward (USPTO, "What are Assignments?" webinar deck, 2015-01-20). US 269,623 expired 1899-12-26 (Google Patents legal events, https://patents.google.com/patent/[US269623](/patent/US269623)/en) — 81 years before database coverage begins.
2. Records for pre-1957 assignments are held by NARA, not by USPTO's searchable index, and are not reel/frame-numbered in the modern sense (37 CFR 1.12(a)(2); USPTO Official Gazette notice that pre-1955/1957 assignment copies are obtained from NARA).

Google Patents' legal-events panel for this patent lists only two events — publication 1882-12-26 and anticipated expiration 1899-12-26 — with no assignment events, consistent with the above.

Therefore there are no reel/frame entries, no conveyance types, no recorded assignors/assignees, and no correspondents of record to report for this patent. Per the assignment-record branch of this analysis, I stop the assignment timeline here rather than populate it with events that were never recorded.

Timeline diagram

The following diagrams documented ownership-relevant events, not recorded assignments. Every event is sourced; no transfer is depicted because none is of record. (Included so the deliverable is complete; treat as an annotated chronology, not a chain of title.)

timeline
    title Ownership-relevant events for US 269623
    1882 : Filed May 3 by Hans Birkholz of Racine WI
         : Issued Dec 26 to inventor with no assignee named
    1889 : Coombs defendant pleads plaintiff never practiced
    1894 : Asserted by Consolidated Roller Mill in equity
         : Claim 1 construed against Barnard and Leas
    1895 : High court appeal pressed only the Gray patents
    1899 : Patent term expires
    1980 : USPTO assignment database coverage begins
         : No assignment records exist for this patent

NPE / troll-pattern signals

All eight signals are assessed against the modern framework. They are structurally anachronistic for an 1882 patent: the assertion economics these signals detect (post-1995 long-lived portfolios, contingency-fee mass filing, IP-holding LLCs, defensive aggregators) did not exist, and the evidentiary substrate — recorded assignments with reel/frame and correspondents — did not exist either. Marks below reflect that.

1. Shell-entity transfer — unclear. No post-issuance assignment of record exists to examine (no database coverage pre-1980). The only adjacent evidence is the pleaded allegation in Consolidated Roller-Mill Co. v. Coombs, 39 F. 25 (E.D. Wis. 1889), that the plaintiff "never [was] engaged in the manufacture, sale, or use" of the patents it asserted. That is a pleading, not a finding, and it is not a recorded assignment. No name-suffix, registered-agent, or single-member-LLC evidence exists — such forms did not exist in 1882.

2. Known asserter in the chain — not present. No assignee in any documented record matches Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, or Spangenberg entities. Consolidated Roller-Mill Company (Racine, WI, active 1880s–1890s) predates all of them by roughly a century and appears on no RPX/Unified Patents high-frequency-plaintiff list.

3. Repeat correspondent across the chain — not present. There is no chain and therefore no correspondent of record. The only names on the instrument are the two signature witnesses, Charles H. Lee and Geo. L. Eddy, who are not recording correspondents and whose appearance is single-instance. No recurrence can be established.

4. Cascading transfers — not present. No transfers of record at all, chained or otherwise.

5. Pre-litigation transfer — unclear. Consolidated Roller-Mill Company asserted the patent by the early 1890s (bill in equity reaching the Supreme Court in 1894–95, 156 U.S. 261 (1895)), but no assignment is dated or documented, so no interval between transfer and suit can be computed.

6. Bankruptcy fire-sale — not present. No Chapter 7/11 proceeding, no 363 sale, no Kodak/Nortel/Polaroid/Sun-style divestiture is implicated. Those proceedings postdate this patent by 100+ years.

7. Privateering — unclear. No SEC filing, Patent Progress, or EFF coverage links any operating company to an assertion vehicle here. The only later Birkholz-surname data point — US 1,204,421 (1916), with International Harvester Corporation taking one-half and Hans E. Birkholz of Milwaukee one-fourth — involves a different patent, a different Birkholz, and a 34-year gap. Insufficient.

8. Defensive aggregator — not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. Those entities did not exist. The patent simply expired 1899-12-26.

Verdict

Insufficient data.

No assignment record exists for US 269,623, and none can: the patent issued December 26, 1882 with no assignee named on its face, and it expired 1899-12-26, eighty-one years before the USPTO electronic assignment database's August 1980 coverage window begins — pre-1957 records having been transferred to NARA under 37 CFR 1.12(a)(2). There are consequently no reel/frame entries, no conveyances, and no correspondents of record against which any NPE signal can be tested; Google Patents' legal-events panel for the patent likewise shows only issuance and expiration. The single defensible observation is a historical one, not an NPE finding: Consolidated Roller-Mill Company of Racine, Wisconsin was asserting the patent in equity by 1894 (The Roller Mill Patent, 156 U.S. 261, 264 (1895)), and in the related Coombs litigation the defendant pleaded that the plaintiff had never manufactured, sold, or used the patents it enforced — a pleading, not an adjudicated fact. That is a 19th-century patent-consolidation-and-assertion pattern, and it is not evidence of any modern NPE relationship.

Verify at: https://assignmentcenter.uspto.gov/ (and the legacy index at https://assignment.uspto.gov/patent/index.html) — search "269623"; expect zero results. Historic pre-1957 assignment records for this patent, if any exist, must be requested from the National Archives and Records Administration, not USPTO.

I'll start by searching for the patent itself and its cited references.

Now let me verify the identity and dates of the key references, starting with the patent cited in the specification itself.

Let me verify the specific reference patents and check whether USPTO records show any examiner-cited references.

Prior-Art Analysis — US 269,623 (Birkholz, "Roller grinding-mill")

Building on the verification summary above; not repeating its bibliographic findings except where needed for the § 102 mapping.

1. Structural finding: US 269,623 has no "References Cited" section

This is the single most important answer to the literal question "look at each patent citation for 269623":

The reason is chronological, not evidentiary: the practice of printing a "References Cited" block on the front page of a U.S. patent did not exist in 1882. The patent as printed (and as mirrored at https://patents.google.com/patent/[US269623](/patent/US269623)/en) contains only the specification, drawings, two claims, and the inventor/witness signatures. Google Patents shows a "Publications (1)" and "Family Applications (1)" block (the patent itself) and no "Patent Citations" or "Non-Patent Citations" block.

Explicit uncertainty. I could not retrieve the original 1882 file wrapper / PatentCenter prosecution record in this session. Therefore I can state with confidence only that no citations are printed on the patent; I cannot rule out that an Examiner's letter of rejection under R.S. §4886 cited references that were never printed. Compare the Gray prosecution, where the Commissioner's Aug. 14, 1879 rejection cited English patent No. 3,328 of 1877 (Lake, for Nemelka) — a reference that likewise does not appear on the face of Gray No. 222,895. So the de facto prior-art record for a patent of this era lives in the litigation and prosecution papers, not on the patent.

What this means for "each patent citation for 269623"

The references actually attributable to US 269,623 fall into three buckets:

1. Art cited by the applicant in his own specification — one reference (US 255,715).
2. Art cited by third parties in litigation — the Gray, Odell, and Nemelka/Lake references pleaded against the Consolidated Roller-Mill patent family.
3. Algorithmic "similar documents" — not citations at all.

2. Reference table for US 269,623

Sources: 156 U.S. 261 at https://supreme.justia.com/cases/federal/us/156/261/ (full text: https://storage.courtlistener.com/harvard_pdf/94092.pdf); 43 F. 527 (N.D. Ill.) at https://law.resource.org/pub/us/case/reporter/F/0043/0043.f.0527.1.html and https://www.courtlistener.com/opinion/[9310612](/patent/9310612)/consolidated-roller-mill-co-v-barnard-leas-manufg-co/; US 255,715 text at https://patents.google.com/patent/[US255715A](/patent/US255715A)/en.

3. § 102 framing — an explicit anachronism warning

35 U.S.C. § 102 did not exist in 1882. The governing statute was R.S. § 4886 (as amended by the Act of 1870), which barred an invention "known or used by others … and not patented or described in any printed publication in this or any foreign country, before his invention … or more than two years prior to his application." The familiar one-year grace period arrived only with the Act of March 3, 1897. So a retro-active § 102(b) analysis of this patent must use two years before May 3, 1882 = May 3, 1880 as the statutory-bar line, not one year. Applying that line:

• Before May 3, 1880 → statutory-bar art (both under old § 4886 and under modern pre-AIA § 102(b)): R2 (Dec. 23, 1879), R4 (Feb. 28, 1878), R5 (1875), R6 (1875), R7 (Nov. 12, 1878), R10.
• Between May 3, 1880 and May 3, 1882 → § 102(a)-type art only (i.e., art must predate Birkholz's invention to qualify): R3 (Mar. 8, 1881), R9.
• After May 3, 1882 → not art at all: R8 (June 20, 1882). Note there was no § 102(e) analogue in 1882, and a post-filing patent cannot be § 102(a) art. R8 is therefore excluded as prior art and belongs only in the infringement-pleading story.

4. Claim-by-claim anticipation mapping

Recall the two claims (quoted verbatim in §"Claims" above):

• Claim 1 = fixed roller-supporting standard + movable roller-carrying casing pivoted thereto + adjustable gage-rod + nut thereof held by the standard + spring connected with said rod and adjustable in tension independently thereof.
• Claim 2 = same + swiveling nut + spring + sliding cap + hand-lever detachably locked to the sliding cap + nut for adjusting spring tension.

R1 — US 255,715 (Birkholz, applicant's own earlier patent)

Full citation: US 255,715 A, "Roller grinding-mill," Hans Birkholz.
Date: before May 3, 1882 (within two years of the 269,623 filing on the number sequence — 252,755 issued Jan. 24, 1882; 260,669 issued July 4, 1882; exact date of 255,715 not confirmed this session).
Description: Nearly identical architecture to the patent at issue — stationary roll in a standard, second roll carried by a swinging casing pivoted on a bolt above the first roll, the casing's weight crowding the rolls together; a spring-loaded bolt J pivoting to the lower end of the casing, passing transversely through the standard, with nut l, washer, and spiral spring k seated in the standard ("By adjusting the nut the tension of the spring may be increased and the pressure between the rolls augmented"); a separate stop screw M with jam-nut N limiting the approach of the hopper-frame so the grinding surfaces cannot touch.
Anticipation: Potentially anticipatory of claim 1 — the combination of a pivoted casing/standard, a transverse adjusting rod with a nut held by the standard, and a spring whose tension is changed by a nut, is all disclosed. It is not anticipatory of claim 2: I found no swiveling nut, no sliding grooved cap, and no detachably locked hand-lever in R1.
Caveat: R1 is the applicant's own earlier patent. Because it is not "by others," it is best treated as an admission against the patentee and as a double-patenting / obviousness-type reference rather than true § 102 anticipatory art — but if its issue date is more than two years before May 3, 1882, the "patented … more than two years prior to his application" clause of R.S. § 4886 would reach it regardless of common inventorship.

R2 — US 222,895 (Gray) — the most dangerous reference

Full citation: US 222,895, William D. Gray, "Roller-Mill," issued Dec. 23, 1879 (application July 1879).
Description (from 156 U.S. 261): frame A; fixed roll B in stationary bearing; roll C journaled in swinging arm D pivoted on bolt E (on an eccentric sleeve F for vertical adjustment); rod G from the stationary bearing to the upper end of arm D; arm D's upper end formed as a spring chamber h containing spring H retained by washer i and wheel nut j (with jam nut k) — turning the wheel nut compresses the spring and crowds roll C toward roll B; nut l and jam nut m set the working position; a shoulder n and nut o at the rod's other end give the stop/separation function.
Anticipation: This is a four-element match to claim 1 — pivoted swinging support carrying the movable roll, a single transverse rod, a nut arrangement held at the fixed/standard end, and a spring whose tension is adjustable by a nut without disturbing the gap setting. The district court said so in terms: "The Birkholz patent seems to me to be only another form of Gray's first patent. I see nothing in his connecting his swinging frame by his rod, F, to essentially differentiate that device from the device shown in the first and second patents of Gray, except that he shows only one rod, and locates that below the rolls instead of above, which it does not seem to me is a patentable difference."
Claim 2: Gray's structure lacks a swiveling nut (Gray's nuts are on a rod anchored in the fixed bearing, and his rod is duplicated on each side of the machine) and lacks the sliding cap / grooved box / detachably locked hand-lever. So R2 anticipates claim 1 in the district court's view but does not squarely anticipate claim 2.
Status note: R2 was held valid but not infringed at 156 U.S. 261; it is a statutory-bar reference against 269,623 because it issued more than two years before the 269,623 filing.

R3 — US 238,677 (Gray)

Full citation: US 238,677, William D. Gray, issued Mar. 8, 1881.
Description: The eccentrics and through-shaft/rod K for working both rods G simultaneously, so the rolls can be thrown apart and back to their exact grinding position without re-adjustment (claims 2 and 3).
Anticipation: Directed to a different problem (simultaneous throw-out) than claim 1 or 2's "adjust spring tension without disturbing the gage adjustment." Weak anticipation value for 269,623. Its significance is doctrinal: the Supreme Court held R3 void for want of novelty over the Nemelka/Lake art (R4–R7), which signals how thin the roller-adjustment art was and how narrow any surviving claim in this family had to be.
Timing: Within two years of the 269,623 filing → § 102(a)-type art only.

R4–R7 — the Nemelka family (Lake English 3,328/1877; Austrian 1875 ×2; French 1875; U.S. 1878)

Description: Multiple forms, all containing provisions for vertical and horizontal roll adjustment. Per 156 U.S. 261 and 43 F. 527: a roll vertically adjustable by a set screw underneath, plus horizontal parallelism adjustment by a sliding bracket supporting a bearing on an eccentric journal operated by a lever; some forms "show, though somewhat imperfectly, a capability of yielding to spring pressure by means of an indiarubber buffer located at the lower end of a long-descending arm of the movable bearing"; "a spring to hold the movable roll to its grinding position and pressure, with means for regulating the pressure of the spring and the grinding distance by means of cams, screws, and nuts"; and the Gray-second-patent feature of throwing the rolls apart by cams connected to a common shaft.
Anticipation: The Nemelka patents are the strongest claim 1 anticipatory candidates on the specific point that matters — independent regulation of spring pressure and of grinding distance by nuts/screws. The district court expressly found all of Gray's adjustments present in them "by substantially the same instrumentality … although somewhat differently placed or modified."
Claim 2: No swiveling nut, no grooved sliding cap, no interlocking hand-lever. Not anticipatory of claim 2.
Timing: All pre-May 3, 1880 → statutory-bar art, and R4/R6 are foreign printed publications independently citable under §4886 / § 102(b).

R8 — Odell reissue No. 10,139

Full citation: Reissue patent No. 10,139, U. H. Odell, issued June 20, 1882.
Anticipation: none. It postdates the May 3, 1882 filing date of 269,623. It is in the record only because it was one of the four patents the Consolidated Roller-Mill Company pleaded; the Supreme Court expressly declined to reach it ("As plaintiff asked for a decree only upon the Gray patents, the others will not be further noticed").
Uncertainty: I could not confirm the number/date of Odell's original patent underlying RE 10,139. If that original issued before May 3, 1882, it would be § 102(a)-type art; I flag this as an open verification item.

R9 — Gray US 228,525 and Odell US 250,954

Raised in the companion litigation (Consolidated Roller-Mill Co. v. Coombs, reported at 39 F. and 43 F.) on the counter-shaft belt-tightening issue, not on roll-gap/spring-tension control. Anticipation of claims 1 or 2: none — different subject matter (multi-roll drive adjustment).

5. Bottom line

Most relevant prior art for US 269,623, in order of potency against claim 1:

1. US 222,895 (Gray, Dec. 23, 1879) — the court found Birkholz "only another form of Gray's first patent," differing only in using one rod instead of two and placing it below rather than above the rolls, which was held not to be a patentable difference. Statutory-bar art (issued >2 years pre-filing).
2. The Nemelka family (US Nov. 12, 1878; Lake/English 3,328 of 1877; Austrian and French 1875) — expressly found to contain a yield spring with "means for regulating the pressure of the spring and the grinding distance by means of cams, screws, and nuts," i.e., the very independence-of-adjustments idea Birkholz claimed. All statutory-bar art.
3. US 255,715 (Birkholz's own earlier patent) — structurally the closest thing to a point-for-point disclosure of claim 1's pivoted-casing + standard-held nut + spring combination, but not art "by others."
4. US 238,677 (Gray, Mar. 8, 1881) — different problem, and itself void for want of novelty.

Claim 2 has no anticipation found. The specific combination of (a) a swiveling gage-rod nut seated in the standard so the rod self-accommodates to the casing's arc, (b) a sliding cap with lugs riding in longitudinal grooves so the cap cannot rotate, and (c) a hand-lever detachably interlocked with that cap to force a deliberate unlock before the gap can be re-set, does not appear in any reference I located. Claim 2 is the narrower and the more defensible claim.

Practical historical outcome: the district court did not hold claim 1 invalid despite expressing doubt — it resolved the case on non-infringement, finding "nothing in the defendant's structure which corresponds to the rod, F, either in function or location." A claim-1 invalidity holding on R2/R4–R7 was never issued.

6. Two corrections / reinforcements to the earlier sections

• No contradiction found, but one emphasis to add: the earlier section listed the litigation prior art only glancingly. The Nemelka/Lake family is arguably more damaging to claim 1 than Gray itself, because the Nemelka patents disclose regulating spring pressure and grinding distance separately — precisely the stated object of the Birkholz patent. Gray instead discloses the structural combination.
• Reinforcing the identifier caution already flagged: the "Similar Documents" list on the Google Patents page (US 301,020; US 457,395; US 269,459; US 240,282; US 255,989; US 266,152; US 236,643; US 229,589; US 444,350; US 416,820; etc.) is a classifier-generated similarity list, not a citation list, and several entries (US 457,395 of 1891; US 301,020 of 1884; US 444,350 of 1891; US 416,820 of 1889) postdate even the issue of 269,623 and therefore cannot be prior art against it under any § 102 subsection. They should not be reported as citations for this patent.

Open verification items I could not close in this session: (i) the exact issue date of US 255,715; (ii) the U.S. patent number for the Nemelka patent of Nov. 12, 1878; (iii) the original patent underlying Odell reissue 10,139; (iv) whether the 1882 file wrapper for 269,623 contains any Examiner citations.

I'll ground this analysis in the prior-art record for this patent before constructing the § 103 combinations.

Now let me pull the specific prior-art references listed in the page's Prior Art / similar-documents section.

Obviousness Analysis — US 269,623 (Birkholz, "Roller grinding-mill")

0. Threshold issues before the § 103 analysis

(a) § 103 does not literally apply to this patent. US 269,623 was granted December 26, 1882 on an application filed May 3, 1882, under the Patent Act of 1870 (R.S. §§ 4886 et seq.). 35 U.S.C. § 103 was not enacted until July 19, 1952, and is not retroactive. The governing requirement was the judicial "invention" standard of Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248 (1850). The era-appropriate formulation appears repeatedly in the roller-mill cases themselves:

"there is nothing beyond mere mechanical skill required in applying these means … It does not call for the exercise of the inventive faculty." — Consolidated Roller-Mill Co. v. Coombs, 39 F. 25 (C.C.E.D. Mich. 1889)
"the improvements … involved only the exercise of mechanical skill, and did not rise to the dignity of invention, such as the law requires in order to justify a patent therefor." — Foos Mfg. Co. v. Springfield Engine & Thresher Co., 49 F. 643 (1892)

I therefore run the requested § 103 framework as an analytical lens, but I flag that the same evidence was, and remains, more naturally framed as pre-§ 103 want of invention. The substantive outcome is the same.

(b) Contradiction in the previously generated sections — flagged. The Litigation summary section states "No litigation is known involving US Patent 269,623" and asserts that 19th-century circuit records were "never digitized." That is directly contradicted by the Patent summary section, which correctly identifies Consolidated Roller-Mill Co. v. Barnard & Leas Manuf'g Co., 43 F. 527 (C.C.N.D. Ill. 1890), and The Roller Mill Patent, 156 U.S. 261 (1895). Both are fully digitized (https://law.resource.org/pub/us/case/reporter/F/0043/0043.f.0527.1.html; https://www.courtlistener.com/opinion/[9310612](/patent/9310612)/consolidated-roller-mill-co-v-barnard-leas-manufg-co/). I adopt the Patent summary section and reject the Litigation summary's conclusion. This matters materially here, because 43 F. 527 contains what is, in substance, a judicial obviousness holding on claim 1.

(c) Critical date / statutory bar — a real limitation on the reference set. R.S. § 4886 barred a patent where the invention "was patented or described in any printed publication … before his invention thereof, or more than two years prior to his application." Two consequences:

• Pre-May-1882 US patents and foreign patents are unambiguously prior art (Gray 222,895; Gray 238,677; Stevens 236,643; Steinmetz 248,118; the Nemelka/Lake family).
• The 1882-dated references (US 255,715; US 255,989; US 265,927) require an invention-date comparison tied to Birkholz's actual date of invention — not a simple filing-date comparison — and I cannot resolve that date from the available record. I use them as corroborating, not primary, references and say so below.

(d) Level of ordinary skill (PHOSITA c. 1882). A millwright or milling engineer with several years' experience building and adjusting roller grinding-mills and the preceding millstone art, familiar with the Gray, Nemelka/Lake, Odell, and Stevens structures then in commercial use. Note for motivation purposes: John Stevens' US 236,643 was issued to a resident of Neenah, Wisconsin — the same state and trade as Birkholz (Racine, Wisconsin), and both were addressed to the same milling market. The art was small, local, and highly aware of itself.

1. The reference set (from the page's Prior Art records plus the cases that construe them)

I did not verify the disclosures of the remaining Similar Documents on the page (US 301,020; US 240,282; US 255,989; US 269,459; US 440,157; US 444,350; US 457,395). I do not characterize them.

2. Claim 1 — element-by-element

"The combination … of the fixed roller-supporting standard, the movable roller-carrying casing pivoted thereto, the adjustable gage-rod, the nut thereof, held by the standard, and the spring connected with said rod and adjustable in tension independently thereof."

Conclusion on Claim 1: obvious. Two independent combinations suffice.

Combination A (primary): R1 Gray '895 + R4 Stevens '643.
Both are in the same field (roller/grinding mills for grain); both address the same problem (setting roll gap and roll pressure without one adjustment corrupting the other). Gray '895 already places a spring and a spring-tension nut (j) and a gap/position nut (l, with jam nut m) on the same rod G — that is Birkholz's entire claimed point, in a two-arm form. Stevens '643 supplies the missing teaching framed in functional terms identical to Birkholz's stated object: the spring stress "will not be disturbed by the mere act of changing the adjustment of the rolls," and shows the grip-adjusting member (hand-wheel sleeve F) structurally separated from the spring-compressing member (nuts h′). The only remaining difference is substituting a pivoted casing for Gray's swinging arms — supplied by R6 (US 255,715, Birkholz's own admitted starting point) and by the Nemelka swinging frames.

Combination B: R6 US 255,715 + R4 Stevens '643. US 255,715 already shows a pivoted casing enclosing the rolls, a transverse rod/nut held in the standard, and a spring on that rod whose tension the nut adjusts — i.e., nearly all of claim 1. Stevens '643 supplies the explicit teaching that the gap adjustment and the spring-stress adjustment should be independent, plus the hand-wheel/locking arrangement. Motivation: the two references are directed to the same portable-mill problem, and Stevens' express recognition of the problem Birkholz set out to solve is the classic "known problem, known solution" situation.

Combination C (corroborative): R2 Gray '238,677 + R3 Nemelka/Lake + R4. Gray '238,677 shows yielding bearings formed by coiled springs plus a hand-lever operating the roll-spacing eccentrics — two distinct actuators. Nemelka/Lake shows a swinging frame, a cam on the frame pivot for roll separation, and a spring "with means for regulating the pressure of the spring and the grinding distance by means of cams, screws and nuts." Adding Stevens' independence-of-adjustment teaching is a routine step.

Why a PHOSITA would combine (KSR-consistent rationales, all supported by 1882 record evidence):

1. Same field, same problem, same result — grain crushing between differential-speed chilled-iron rolls (39 F. 25 describes the art's transition from millstones).
2. Explicit problem recognition in the references themselves — Stevens states the exact result Birkholz claims as his object; Birkholz's specification itself concedes the starting structure (US 255,715).
3. Only a finite number of identified, predictable solutions to the dual-adjustment problem: (i) two separate rods (Gray '238,677; US 265,927's tempering rod F + distance rod G); (ii) one rod with two threaded members — one for gap, one for spring tension (Gray '895: nut l for position, wheel nut j for tension); (iii) one rod with a positive lock on the adjusting member (Stevens' dial lock g′ and nuts h′). Birkholz selected option (ii) with a lever. That selection is routine.
4. Design incentive arising from the machine's own operating environment — Birkholz's mill is a portable mill subject to vibration; the whole art was preoccupied with vibration-proofing adjustments (Gray's jam nuts k, m; US 255,715's jam nut N; Stevens' locking bolt g′; and Birkholz's own "reciprocal locking" feed-slide). Providing a positive interlock so the gap setting cannot drift while pressure is changed is the obvious response to a known nuisance.
5. Predictable result, no new cooperation of parts — each element performs exactly its old function: the rod gages, the spring presses, the nut tensions. Under both modern § 103 and the 19th-century aggregation doctrine (mere juxtaposition of old parts with no new cooperative result), this is not patentable subject matter.
6. Judicial confirmation. In 43 F. 527 the court stated: "The Birkholz patent seems to me to be only another form of Gray's first patent. I see nothing in his connecting his swinging frame by his rod, F, to essentially differentiate that device from the device shown in the first and second patents of Gray, except that he shows only one rod, and locates that below the rolls instead of above, which it does not seem to me is a patentable difference." That is a straightforward obviousness/mere-change conclusion on the very claim at issue. (Caveat stated plainly: the court then rested its decree on non-infringement, and the Supreme Court expressly declined to reach Birkholz — "as plaintiff asked for a decree only upon the Gray patents; the others will not be further noticed," 156 U.S. at 262.)

3. Claim 2 — element-by-element

Claim 2 adds the swiveling nut, the sliding cap, the hand-lever, the detachable lock between lever and cap, and the separate tension nut. Every added element is separately old:

Conclusion on Claim 2: obvious a fortiori. Claim 2 is narrower than claim 1 (it contains every claim-1 element plus five more). Since claim 1 is obvious, claim 2 can only survive if the additional elements supply patentable weight — and each is individually disclosed or plainly suggested by R1, R2, R4, R5, and R6, with the same functions they perform in Birkholz. The interlocking-lever feature is, at most, the substitution of a square-cornered tooth lock for Gray's jam nut or Stevens' positive locking bolt, with the predictable result of requiring deliberate force to change the gap setting.

4. Secondary considerations — none of record

• No unexpected result is asserted. Birkholz's specification states only the intended, predictable object (gap and tension independently adjustable). No comparative data, no criticality of parameters.
• No nexus-bearing commercial success is established in the accessible record. The 1895 litigation concerned the Gray patents, not Birkholz, and the lower court found the accused mill contained nothing corresponding to rod F "either in function or location."
• The one arguably novel sub-feature was disclaimed. Birkholz expressly reserved the feed-slide/rod-N arrangement "in a separate patent." It therefore cannot supply patentable weight, and its very existence shows the drafter knew how to separate subject matter.
• Claim breadth is self-limiting. Both claims close "substantially as before set forth," which by 1880s practice (39 F. 25; Sargent v. Lock Co., 114 U.S. 86) confined Birkholz to the described structure and effectively conceded that the inventive contribution lay in a specific arrangement of old parts.

5. Residual uncertainties I will not paper over

1. US 265,927 is used only as corroboration; its issuance date is unverified, and if it postdates May 3, 1882 without an earlier filing date it is not prior art at all.
2. US 255,715's availability turns on R.S. § 4886 and Birkholz's actual invention date, not merely on its 1882 grant. I use it primarily as Birkholz's own admission of the prior structure, which is legitimate regardless of statutory-bar mechanics.
3. US 255,715's named inventor did not appear in my search results; I do not attribute it to Gray, notwithstanding the stylistic similarity.
4. Reissue 10,139 (Odell) was pleaded in the 1895 suit but not adjudicated on the Birkholz point; I use it only for the hand-lever disclosure attributed to Odell's mill in Consolidated Roller-Mill Co. v. Wegman (22 F. 160).
5. Minor internal date inconsistency across the previously generated sections: one states "Today's date: 2026-09-30" and the other "Current Date: April 26, 2026." Immaterial to the analysis, but noted for the record.
6. I did not verify the content of six of the Similar Documents listed on the page (US 301,020; 240,282; 255,989; 269,459; 440,157; 444,350; 457,395). If any of them was fetched and used in the Prior Art section of this page, it should be added to the charts above; I cannot vouch for them.

6. Bottom line

Applying the § 103 framework to US 269,623 (and, more aptly, the pre-1952 "invention" standard that actually governed it), both claims are invalid as obvious over the roller-mill art of 1875–1881:

• Claim 1 is obvious over Gray US 222,895 in view of Stevens US 236,643, further in view of the pivoted-casing structure of US 255,715 (cited in Birkholz's own specification) or the Nemelka/Lake swinging frame. Gray already puts a spring-tension nut and a gap nut on one rod; Stevens expressly teaches that changing the roll adjustment must not disturb the spring stress.
• Claim 2 is obvious over the same set, with the swiveling nut supplied by Steinmetz US 248,118 or the Nemelka/Lake self-aligning attachments, the hand-lever by Gray US 238,677 or Odell reissue 10,139, and the positive lock by Gray's jam nut k or Stevens' locking bolt g′.

The claimed advance reduces to using one rod instead of two, with two separate threaded members on it, and locating it below rather than above the rolls — a change of number, location, and degree that the C.C.N.D. Ill. expressly held, in 43 F. 527, "does not seem to me … a patentable difference." The record contains no secondary consideration, no unexpected result, and no teaching away.