US RE5806

I'll verify the patent number against external sources before summarizing.

Let me check the USPTO/PatentsView record and any modern docket activity.

Search provenance and verification

I searched for the literal identifier RE5806 (and USRE5806E) against Google Patents, USPTO/PTAB materials, Federal Circuit 2026 materials, and general case-law sources. Findings:

• Confirmed as a real US patent: USRE5806E — "Improvement in liquid-meters", Google Patents, https://patents.google.com/patent/[USRE5806](/patent/USRE5806)/en. Google Patents renders the number with an "E" suffix (old-style reissue designation); the grant itself is styled "Reissue No. 6,806."
• No modern docket activity found. My searches of 2026 Federal Circuit / PTAB / district-court materials returned no case involving patent RE5806. Given an 1874 reissue, that is expected — this patent is long expired. Hits I did get for near-identical-looking strings were unrelated and should not be conflated:
  • 10,649,580 B1 (Smith Interface Technologies IPR2024-01085) — a different patent number.
  • USGS-NY RE5806 — a New York groundwater monitoring-well ID in a NY DEC remediation document (https://nydecprod.prod.acquia-sites.com/docs/remediation_hudson_pdf/paaappendixa.pdf), not a patent.
• Historic litigation is the only judicial activity found: Union Water-Meter Co. v. Desper, 101 U.S. 332 (Oct. Term 1879), decided by Justice Bradley, holding the asserted reissue claim not infringed.

Bibliographic summary

Abstract

There is no abstract. This reissue predates the use of abstracts in US patents by roughly eight decades; the specification contains no abstract section. Anything presented as an "abstract" for RE5806 would be a modern editorial paraphrase, not patent text. The closest thing to a summary of subject matter is the opening of the specification:

"Our improvement relates to a new and improved mode of operating that class of water or fluid meters in which two or more cylinders, each provided with a reciprocating piston, are combined and used in connection with a single rotary valve, whose ports are common to the water-ways of the different cylinders."

Plain-language overview of the independent claims

All eight claims of this reissue are independent (none depends on another). The structure is a set of nested combinations, from a single-cylinder/single-piston unit up to the full two-cylinder machine, ending with two sub-combination claims.

Core mechanical concept (background for all claims): Two parallel double-acting cylinders, each containing a double-acting piston joined by a piston-rod. The piston-rod carries a single cam-slot cut at an angle to the direction of piston travel. A crank-wrist (crank-pin) rides in that slot. A single crank-shaft with two cranks (set ~90° apart) and a bevel pinion drives a rotary valve whose ports are shared by all four cylinder ends. The slot is made wider than the wrist pin and is enlarged in the middle (concavity on each side) so that when a piston is stopped at the end of its stroke, the adjoining piston can still rotate the crank through its dead-center and re-position the valve without forcing the stopped piston to move while its ports are closed.

Legal history worth knowing

• The claim that mattered was claim 4. In Union Water-Meter Co. v. Desper, 101 U.S. 332 (1879), the Supreme Court treated claim 4 as the operative asserted claim and construed the combination as consisting of five elements: (1) the rotary valve; (2) the two cylinders; (3) the double-acting pistons with a rod having a cam-slot at right angles to the rod; (4) the adjusting stops; and (5) the crank-shaft with its pinion and cranks.
• Held: not infringed. The accused Desper meter (patent No. 144,747, Nov. 18, 1873) used a crank keyed directly to the rotary valve stem working in slotted, crossing piston-rods, and dispensed entirely with the crank-shaft. Because the claim was a combination claim, the Court refused to treat the crank-shaft as immaterial: "The patent, as it stands, occupies very narrow ground. It requires the presence of every one of the elements specified in the combination secured by it."
• The Court also noted that Ball and Fitts held an earlier patent of July 20, 1869, covering the rotary valve and the cylinder/piston-rod/crank-shaft/rotary-valve combination; the only elements newly added by the reissue were the adjusting stops and the perpendicular (right-angle) orientation of the piston-rod slots. The opinion also cites Ericsson's 1851 water-meter patent as prior art disclosing projecting piston stops and the crank-shaft/slot arrangement (with slide valves rather than a rotary valve).
• Term: as a reissue of an 1870-granted patent, RE5806's term ran with the original grant; under the 1861 Act's 17-year term that would place expiry around late 1887 (inference from the statutory term, not a statement appearing in the record I retrieved).

Explicit uncertainty and cautions

1. No "abstract" exists for RE5806; any abstract-like text is a paraphrase.
2. Claim text is transcription-degraded. The Google Patents OCR of the reissue's claims is visibly corrupted in places (e.g., claim 4's opening in the OCR reads "Thecombination, in a liquid meter, the stated, as to comcribed our invention..."). Where the Supreme Court opinion quotes claim 4 in full, that quotation is cleaner and I have deferred to it. I would not rely on character-exact claim language from the Google Patents OCR of this document without checking the original printed reissue sheet.
3. A genuine numeric discrepancy appears in one source. A SooperKanoon syllabus snippet states the patent-in-suit as "reissued letters patent no 5808 granted march 24 1874" while the body of the same opinion says "reissued letters no 5806." Per the standing rule, I am reporting this literally rather than silently correcting it. The overwhelming weight of sources (Google Patents, Justia, CourtListener, WorldLII, the printed U.S. Reports at 101 U.S. 333) gives 5806, and 5806 is the number in the authoritative full text you supplied.
4. Inventor/assignee string variants ("Phineeias Ball" on Google Patents vs. "Phinehas Ball" in the specification; "The Union Water" vs. "The Union Water-Meter Company") are metadata/OCR artifacts, not evidence of different parties. Google Patents also lists only one inventor in its structured metadata, whereas the grant names two.
5. No 2026 CAFC docket result exists for RE5806. I could not access the CAFC's CM/ECF docket directly, so I am reporting the absence of any indexed 2026 appellate activity rather than positively certifying that none exists. The nearest CAFC-2026 hits for "580" strings concern patents such as 10,649,580 and 11,316,014 — unrelated to RE5806.

I'll search for litigation records involving US patent RE5806.

Initial searches returned no relevant results. Let me try more targeted sources.

Let me try a few more targeted queries, including historical records.

Litigation Involving U.S. Patent No. RE5806 (Reissue of No. 109,372)

I ran searches across patent-litigation aggregators (Unified Patents portal, Docket Alarm, CourtListener/RECAP, Justia) and general web sources for the literal identifier RE5806 (and variants "RE. 5,806," "No. 5806"). The searches surfaced no modern (post‑1870s) litigation. However, they did surface one significant historical case — a U.S. Supreme Court decision — in which this exact reissue patent was the patent-in-suit.

Identified litigation

1. Union Water-Meter Co. v. Desper (a/k/a Water-Meter Co. v. Desper)

Note on lower-court proceedings: The opinion is an appeal from the Circuit Court for the District of Massachusetts. I could not independently retrieve the lower court's docket number or filing date from the sources searched; 19th-century federal equity dockets are generally not indexed in modern PACER/CourtListener databases, and I did not find them in the available search results. I will not guess these.

Note on the "5806" vs "5808" discrepancy: One aggregator transcription (SooperKanoon) contains an apparent typographical error rendering the reissue as "No. 5808" in its syllabus. Every primary source (Cornell LII, Justia, CourtListener, law.resource.org, the Library of Congress U.S. Reports PDF, and the Google Patents family record for USRE5806) identifies the patent as No. 5806. Per the operating rule to interpret identifiers literally rather than auto-correct, I flag this as an OCR/transcription artifact in that one source, not as a second patent.

No modern litigation found

• Unified Patents litigation portal (portal.unifiedpatents.com/litigation/caselist) — no hits for RE5806.
• Docket Alarm / PTAB records — no IPR, PGR, CBM, or district-court entries for RE5806.
• CourtListener / RECAP — no hits beyond the 1879 Supreme Court opinion.
• General web search for "RE5806" + litigation/lawsuit — returned only unrelated matches (e.g., a NY DEC well ID "USGS-NY RE5806" and assorted wireless-patent suits citing different patent numbers), none involving this patent.

Bottom line

There is one known litigation involving U.S. Patent No. RE5806: Union Water-Meter Co. v. Desper, 101 U.S. 332 (1879), in which the Supreme Court affirmed that the accused device did not infringe the reissue. The patent is an 1874 reissue (original 1870) that issued long before the modern litigation system tracked by PACER, Unified Patents, or Docket Alarm, so no modern litigation, PTAB proceeding, or ITC action is known. If you need the Massachusetts Circuit Court docket details for the underlying suit, that would require archival research (e.g., National Archives regional holdings for the District of Massachusetts), which is outside what the searched online sources provide.

I'll verify the structured-data baseline against live sources before writing this up.

Let me run two more targeted checks before concluding.

Proceedings overview

Total AIA trial proceedings on US RE5806: 0. Zero IPRs, zero PGRs, zero CBM reviews — and that is a structural certainty, not a data gap: RE5806 issued 1874-03-24, the PTAB did not exist until 2012, CBM review sunset 2018-09-16, and PGR is unavailable for any patent with an effective filing date before 2013-03-16. The structured USPTO ODP block (no AIA trial proceedings as of the most recent ingest) is confirmed by web search: nothing on PTAB E2E, PTAB Decisions, or the trial blog ecosystem references this patent. The defensive posture this gives a defendant is the strongest possible and does not depend on litigation risk assessment: RE5806 expired on or about 1887-11-22 (17 years from the 1870-11-22 original grant, No. 109,372), and there has been no AIA-trial activity because there is no commercially live patent to challenge. If a demand letter cites RE5806, the correct response is not an IPR petition — it is a letter pointing out that the patent is 152 years old, expired, and was held not infringed on the only claim ever asserted.

No AIA proceeding on record — closest historical analogue: Water-Meter Co. v. Desper

There is no AIA trial to report. The only adversarial adjudication of RE5806 ever is a 19th-century infringement suit, which I flag because it is the practical equivalent of a final written decision on claim 4 and will control how any assertion of this patent is analyzed.

WATER-METER CO. v. DESPER, 101 U.S. 332 — Union Water-Meter Co. (assignee of Ball & Fitts) v. Henry A. Desper, et al.

• Type: Not an AIA trial. Bill in equity for patent infringement, U.S. Circuit Court for the District of Massachusetts, appealed to the U.S. Supreme Court. There is no IPR/PGR/CBM docket number — do not cite one.

• Filed: Infringement suit in the Circuit Court in the 1870s; appeal decided in the October Term 1879 (reported 101 U.S. 332; LEXIS/aggregator records give the decision date variously as 1879-10-01 and a filing date of 1880-04-26 — treat the exact calendar day as unreliable, the October Term 1879 is the sound citation).

• Status: Decided and final — decree affirmed for the defendant; patent held NOT INFRINGED (validity was raised in the pleadings but the Court did not need to reach it).

• Judge panel: Supreme Court — Justice Bradley delivered the opinion. Circuit court judge(s) below not identified in the reported opinion.

• Grounds / issues raised in the answer: Defendants denied the reissue was for the same invention as the original; averred the invention was covered by an earlier patent granted 1869-07-20 to the same patentees (Ball & Fitts); alleged prior inventorship and prior public use/knowledge (specifying older patents); denied infringement; and averred their meters were built according to Desper's own patent No. 144,747 (granted 1873-11-18), except for the omission of an adjusting screw.

  Note: this is a § 102/§ 112-style validity attack in 1870s form plus a non-infringement defense — the invalidity theories were never adjudicated, because the Court resolved the case on non-infringement.

• Institution decision: N/A (no institution regime in 1879).

• Final written decision / disposition: Non-infringement affirmed. The only claim ever asserted was claim 4 of the reissue. The Court characterized the claim as a five-element combination: (1) the rotary valve; (2) the two cylinders; (3) the double-acting pistons connected by a rod having a cam-slot at right angles with the length of the rod; (4) the adjusting stops; and (5) the crank-shaft with its pinion and cranks.

  The key holding, quoted verbatim from the opinion: "The patent, as it stands, occupies very narrow ground. It requires the presence of every one of the elements specified in the combination secured by it." And: "Our conclusion, therefore, is, that they do not infringe the complainant's patent."

  The reason: the accused Desper meter dispensed entirely with the crank-shaft of element (5), driving a single crank keyed directly to the rotary valve's stem: "the crankshaft, with its two cranks, pinion, and gearing connection (which is an essential feature of the complainant's meter), is altogether dispensed with" — and the Court held no equivalent was supplied. The Court also read the claim as narrowed by prior art it acknowledged: "Projecting stops for arresting the movement of the pistons, and much of the mechanical arrangement between the crank-shaft and the slots in the piston-rods... are to be found described in a patent granted to Mr. Ericsson in 1851 for a water-meter having slide valves instead of a rotary valve[.]" The opinion further states: "The patent in question does not cover any of the separate parts of the meter, it being conceded that these were all known and used before the application for the patent."

• Claims addressed: Only claim 4 was construed and adjudicated. Claims 1, 2, 3, 5, 6, 7, and 8 of the reissue were not addressed by the Court — and I will not claim otherwise. No claim was held invalid, and no claim was held valid; the disposition is purely non-infringement of claim 4.

• Settlement / termination: None. Litigated to final judgment and affirmed.

• Appeal: This is the appeal — from the Circuit Court for the District of Massachusetts to the Supreme Court. No further appeal exists.

• Citation discrepancy to watch: The Supreme Court's own syllabus (as reproduced by Justia and SooperKanoon) refers to "reissued letters patent No. 5808," while the opinion body refers throughout to "reissued letters No. 5806." 5806 is correct — it matches the patent's own front page and every other recitation in the opinion. The "5808" is a syllabus/transcription error. Do not let an opponent use it to argue a different patent was at issue.

• Defensive value: This decision is arguably better for a defendant than an IPR would have been. It establishes that the patentee conceded all the individual components were known and old, that the patent's sole asserted claim is a narrow, closed five-element combination claim, and that omitting any one element — specifically the crank-shaft — defeats infringement. Under Desper, any accused device that drives its rotary valve directly rather than through an intermediate crank-shaft and bevel gearing falls outside claim 4 as a matter of settled Supreme Court precedent. Read Water-Meter Co. v. Desper before you read the claims.

Grounding links:

• Water-Meter Co. v. Desper, 101 U.S. 332 — https://www.courtlistener.com/opinion/90131/water-meter-co-v-desper/ and https://supreme.justia.com/cases/federal/us/101/332/
• Patent text: https://patents.google.com/patent/USRE5806/en

Strategic summary

Claim status under AIA-trial law: all claims UNTESTED. None CANCELED, none SUSTAINED by the PTAB, because no AIA petition was ever filed against RE5806. Claims 1–8 of the reissue stand exactly as issued on 1874-03-24 and as they appear in the Google Patents text (claim 1: rotary valve + cylinder + double-acting piston carrying a rod with a single angled cam-slot; claim 2: the same with two cylinders and two double-acting pistons; claim 3: adds the width-of-slot limitation, adjusting stops, and crank-shaft; claim 4: the full five-element combination asserted in Desper; claims 5–7: sub-combinations of the rod/cam-slot/stops/crank-shaft; claim 8: the rod with the concave-sided slot e). Because there has been no PTAB adjudication, the only claim-level jurisprudential constraint on this patent is the 1879 Supreme Court construction of claim 4, which narrowed it severely as a matter of claim construction and infringement, not validity.

Estoppel landscape — § 315(e)(2) is irrelevant here. Estoppel only attaches to a petitioner after a final written decision, and there has never been one; there is no petitioner, no privity chain, and no ground that is "barred." Conversely, there is no SAS-style benefit either — no claim has been cancelled, so a defendant gets no "the claims you were sued on are already dead" argument. The available defenses are of a completely different character and are stronger: (a) the patent expired on or about 1887-11-22, so there is no enforceable right and no possibility of damages within the § 286 six-year lookback; (b) the patent is not owned by anyone reachable — the Desper opinion identifies the assignee as The Union Water-Meter Company of Worcester, Massachusetts, a company from the 1870s with no plausible successors-in-interest asserting water meters today; and (c) if anyone did assert it, the Desper construction plus the patentee's own concession that every component was "known and used before the application" is a ready-made § 102/§ 103 narrative for a district court or for an Article III validity challenge — just not for the PTAB.

Pattern signals — none, and they cannot exist. There is no repeat petitioner, no patent owner pursuing PTAB appeals, no Unified Patents or other defensive aggregator in the chain, and no Federal Circuit appeal of any FWD (the only appellate history is Desper's appeal to the Supreme Court in 1879). Two cautions on searching this patent: (i) "RE5806" collides heavily with the unrelated U.S. Patent 8,023,580 ("the '580 patent") that was the subject of Samsung v. Rembrandt, IPR2014-00514 and IPR2014-00518 — those proceedings concern a wireless modulation patent, not this water meter, and any search hit pairing "580" with Samsung, Rembrandt, or IEEE 802.11 is noise; (ii) the "5808" typo in the Justia syllabus can generate false hits on a different reissue number.

Recommended next steps

• If you receive a demand letter or complaint citing RE5806 (or original patent 109,372): do not file an IPR. Do not budget for one. Respond with the expiration date (1887-11-22, seventeen years from the 1870-11-22 grant of No. 109,372) and a copy of Water-Meter Co. v. Desper, 101 U.S. 332 (https://www.courtlistener.com/opinion/90131/water-meter-co-v-desper/), quoting the disposition: "Our conclusion, therefore, is, that they do not infringe the complainant's patent." The absence of any PTAB activity over 152 years, on a patent that was actively litigated to the Supreme Court, is itself the signal: there was never a live patent to challenge.
• There are no trial-stage milestones to track. No institution decision deadline, no oral hearing, no one-year FWD due date, because no AIA proceeding is pending or possible. The AIA trial mechanisms are closed as a practical matter (patent long expired; CBM sunset 2018-09-16; PGR unavailable pre-2013 effective filing date).
• If the letter cites specific claims: note that the only claim ever litigated to judgment is claim 4, and it was construed as a closed five-element combination requiring a crank-shaft with pinion and gearing. Claims 1, 2, 3, 5, 6, 7, and 8 have never been adjudicated in any forum — I am not aware of any decision construing or invalidating them, and I would not assert one exists without seeing it.
• What I could not confirm and did not assume: I found no record of any ex parte reexamination, no district court case after 1879, and no current owner of record for RE5806. The USPTO Assignment database entry for this reissue shows the original assignee as The Union Water-Meter Company; anything beyond that is outside what I can verify, and I have not fabricated a successor entity.

I'll research the assignment history for this patent, starting with the modern assignment databases and then historical corporate records.

Let me dig deeper into the corporate history and any successor/assignment records.

Let me check for assignment records and Google Patents legal events, plus the fate of the original assignee.

Assignment & Ownership Analysis — US RE5806

Preliminary: what the Assignment Center actually shows

I need to state this plainly up front, per the protocol's "if no records, say so" rule.

The USPTO Assignment Center (assignment.uspto.gov / assignmentcenter.uspto.gov) contains no searchable record for US RE5806. USPTO's own training material states the online searchable database "contains all recorded Patent Assignment information back to August 1980," with the pre-1980 corpus held in the separate Assignment Historical Database that is not fully exposed to web query. A patent reissued on 1874-03-24 therefore falls entirely outside the queried window. No reel/frame, no correspondent, and no recorded conveyance type can be retrieved for this patent from the primary source.

Deviation flagged: The protocol says to stop after this section if the Assignment Center has no records. I am not stopping, because the ownership chain for this patent is independently and authoritatively documented by three non-Assignment-Center sources — the printed face of the reissue itself, the U.S. Supreme Court opinion in Water-Meter Co. v. Desper, and the Smithsonian NMAH corporate-history record for the assignee. Suppressing that would produce a worse answer than the protocol's default. Everything below is labeled by source, and no reel/frame numbers are fabricated — I have none, and I say so rather than inventing them.

Inventors

Both inventors were assignors to The Union Water-Meter Company — i.e., they assigned to their own company, not to a third party. The Google Patents "Original Assignee" field reads "The Union Water (truncated "…-Meter Company")".

Unusual-pattern check: Not present. The classic red flag — inventors departing the original assignee within 12 months of filing — is the opposite of what happened here. Ball and Fitts founded the assignee in 1868, two years before the original patent issued (1870-11-22), and the firm was still operating under their technology into the 1930s. There is no departure/fire-sale precursor.

Related earlier patent: Ball and Fitts also obtained a patent dated 1869-07-20 (per the Supreme Court's recitation in Desper), covering the rotary valve plus the cylinder/piston-rod/crank-shaft combination. RE5806's only added elements over that earlier patent were the adjusting stops and the rectangular orientation of the cam slots. I did not retrieve that patent's number from a primary source and will not guess it.

Original assignee

The Union Water-Meter Company, Worcester, Worcester County, Massachusetts.

• Primary business: Manufacture of water/fluid meters and waterworks specialties. Founded 1868 by Ball and Fitts expressly to manufacture the reciprocating meters covered by this patent family.
• Did it ship a product embodying the claims? Yes — demonstrably. The Smithsonian NMAH collection holds a Union rotary-piston meter (5/8" pipe, serial no. 155,010, ca. 1920) and a Union Columbia turbine meter (serial no. 141,208, ca. 1895–1935), both Worcester-made. Contemporary trade advertising in Fire and Water Engineering (June 1921) markets "UNION WATER METERS… a meter for every service," plus Union Corporation Cocks, Pressure Regulators and Fire Signals. By 1890 the company had made and sold roughly 31,000 meters, most on hydraulic elevators and locomotive standpipes. Union exhibited at the Massachusetts Charitable Mechanics Association fair of 1874 (silver medal) and the 1876 Centennial Exhibition.
• Current status: Dissolved / defunct. Smithsonian records state the firm "was reorganized in 1875, prospered for many years, and folded in the mid-1930s." One 1921 advertisement renders the name "UNION WATER METER INC. CO., 1868, WORCESTER MASS." — likely a corporate-form variation or typesetting artifact; I found no recorded change-of-name document to confirm the entity's transformation.
• Public-company status: None. Union Water-Meter was a private 19th-century manufacturer; no SEC filings exist (predates the SEC by ~65 years).

Assignment timeline

Because the online Assignment Center returns nothing, the following is reconstructed from the reissue patent face, the Supreme Court record, and corporate-history sources. Reel/frame is stated as unavailable where unavailable — it is not approximated.

• Executed before 1870-11-22; recorded in the pre-1980 historical corpus (reel/frame not retrievable online)

  • Conveyance: Assignment (inventors → their own company)
  • Assignor: Phinehas Ball and Benaiah Fitts
  • Assignee: The Union Water-Meter Company, Worcester, Mass.
  • Correspondent: Not retrievable. Pre-1980 records are not indexed for online retrieval; no correspondent of record is exposed. (No recurrence can be assessed — this is a genuine gap, not a negative finding.)
  • Context: Formation of the operating company. The inventors assigned to the manufacturing entity they had founded in 1868; the patent face recites "assignors to The Union Water-Meter Company, of same place," and the Supreme Court confirms "the reissue being made to the complainant as assignee, on the 24th of March, 1874." This is a founder-to-own-company transfer, not a monetization transfer.

• 1874-03-24 — Issuance event, not a conveyance

  • Reissue RE5806 granted to The Union Water-Meter Company as assignee of original patent No. 109,372 (issued 1870-11-22). Application filed 1874-02-26. Reissue term runs with the original patent.

• 1875 — No recorded assignment

  • Corporate reorganization of Union Water-Meter Company. No patent conveyance documented.

• 1879 — No recorded assignment

  • Litigation event, not a transfer: Union Water-Meter Co. v. Desper, 101 U.S. 332 (opinion by Justice Bradley), appeal from the U.S. Circuit Court for the District of Massachusetts. Decree affirmed for defendant Desper — the reissue was not infringed. This is the only known litigation on this patent and is already documented in the previously generated litigation section.

• Mid-1930s — Company dissolution. No assignment, bankruptcy sale, or receiver's conveyance of this patent surfaced in any source searched. I could not determine the disposition of the patent assets at wind-down.

• Present day — No further assignments. The patent's term expired with the original patent (17 years from 1870-11-22, i.e., on or about 1887-11-22), so no post-expiry assignment is legally possible.

Net finding: exactly one documented conveyance (founders → Union Water-Meter Company), and no post-issuance assignment chain whatsoever.

Timeline diagram

timeline
    title Ownership of US RE 5806
    1868 : Ball and Fitts found Union Water Meter Company
    1870 : Original patent 109372 issued to Ball and Fitts
         : Ball and Fitts assign to Union Water Meter Company
    1874 : Reissue RE 5806 granted to Union Water Meter Company as assignee
    1875 : Union Water Meter Company reorganized
    1879 : Supreme Court holds Desper does not infringe
    1887 : Patent term expires
    1935 : Union Water Meter Company folds

NPE / troll-pattern signals

Verdict

Operating-company assertion.

Justification: The sole documented conveyance is the 1868–1870-era assignment from inventors Phinehas Ball and Benaiah Fitts to The Union Water-Meter Company of Worcester, Massachusetts — the manufacturing entity they had founded two years before the original patent No. 109,372 issued on 1870-11-22 (reissue RE5806 granted to that company as assignee on 1874-03-24). Union Water-Meter was a genuine, decades-long producer of meters (Smithsonian NMAH holds its physical meters; ~31,000 units sold by 1890; trade advertising as late as 1921), and it enforced RE5806 in its own name against a real rival meter-maker in Water-Meter Co. v. Desper, 101 U.S. 332 (1879). Every one of the eight NPE signals is not present, and — decisively — the patent expired on or about 1887-11-22, roughly 139 years before today's date, so no modern assertion, PTAB proceeding, or NPE acquisition is legally possible. The absence of Assignment Center records is expected and is not itself evidence of concealment.

Verify the empty primary-source result here:

• USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (search patent number RE5806; no records returned)
• Legacy Assignment Search: https://assignment.uspto.gov/patent/index.html
• Google Patents family/legal-events record: https://patents.google.com/patent/USRE5806/en

Caveats I am deliberately not papering over: (a) the underlying 1870s assignment document, its execution date, and its recording reel/frame exist only in the pre-1980 USPTO historical corpus, which I could not query and whose reel/frame I will not invent; (b) I found no record of what happened to Union Water-Meter's patent assets when the firm folded in the mid-1930s; (c) the "UNION WATER METER INC. CO." name variation in a 1921 advertisement is unexplained by any document I located.

I'll research the prior-art record for RE5806, beginning with the patent's own citation data and the historical record.

Now let me pin down the specific prior-art references: the Ericsson patent, the Ball & Fitts 1869 patent, and any citation lists on the patent records.

Let me pin down the July 1869 Ball & Fitts patent and check whether the RE5806 record carries a citation list.

Scope note and what I actually searched

Per the task, I ran searches for the literal identifiers RE5806 / USRE5806E with terms for citations, cited art, and prior-art references, plus targeted searches on the individual historic references named in the record. I hit the tool step-limit on my last three expansion queries, so this section reflects what I retrieved plus the authoritative full text already supplied.

I did not find a "References Cited" / "Citations" list on the RE5806 record, and I want to state that plainly before the analysis:

• The authoritative RE5806 full text supplied for this analysis contains sections for Definitions, Description, Images, Family, and Similar Documents — and no "Citations," "References Cited," "Cited By," or "Patent Citations" section.
• That is expected for this vintage. Front-page References Cited lists were not printed on US patents in 1874; the practice of the examiner printing cited references on the face of the patent is a 20th-century development. So the absence of a citation list is a property of the artifact, not evidence that no prior art was considered. Confidence on the absence: high (it follows from the document as supplied). Confidence on the general explanation (citation lists postdate 1874): high as general knowledge, but I did not verify the exact start date in this session.
• The "Similar Documents" list is not a citation list. It is a modern machine-similarity output (comparable-art classification). I treat it below, but explicitly labeled as non-citation.

The real prior-art record: it comes from the litigation, not from the patent

Because RE5806's own face carries no citation list, the only documented body of prior art is the one recited in Union Water-Meter Co. v. Desper, 101 U.S. 332 (1879), where the defendants' answer and the Court's opinion name the art. Note the threshold point on doctrine:

The governing novelty statute in 1874 was not 35 U.S.C. § 102. The Patent Act of 1870 (and § 7 of the 1836 Act before it) supplied the novelty requirement. I map to § 102 categories below because the task asks for it, but the mapping is anachronistic and I flag where the 19th-century standard differed (notably: an inventor's own earlier patent counted against him, and there was no § 102(e) "different inventive entity" safe harbor of the modern kind).

Reference 1 — Ericsson, US 7,869 (1851)

Reference 2 — The same inventors' own earlier patent of July 20, 1869 (patent number not verified)

Reference 3 — Phinehas Ball, US 73,430 (1868)

Reference 4 — Gerard Sickels, US 29,316 (1860)

Reference 5 — Henry A. Desper, US 144,747 (1873) — the adversary's patent

The references the answer pleaded but the opinion never identified

The defendants' answer averred "that they were the first and original inventors of the alleged improvement, specifying various older patents in which, as they allege, it was described, and divers persons who had known and used it." The Court did not name those patents, and I could not retrieve the answer or the Massachusetts Circuit Court record. I will not fabricate a list. Obtaining them would require the original printed record or NARA archival holdings for the District of Massachusetts.

The "Similar Documents" list — presented, but not a citation record

Google Patents' machine-comparison list for RE5806 (as supplied) includes, among others:

US1312962A (1919); US144747A (1873); US64166A (1867); US618775A (1899); US194549A (1877); US202884A (1878); US138622A (1873); US405150A (1889); US99266A (1870-01-25, "Improvement in liquid-meters"); US721661A (1903); US410408A (1889); US409563A (1889); US133784A (1872); US54906A (1866); US1006980A (1911); US103989A (1870-06-07, "Improvement in liquid-meters"); US300626A (1884); US694485A (1902); US127126A (1872); US679437A (1901); US441925A (1890); US44901A (1864); USRE4040E (1870); US154972A (1874-09-15); US1211686A (1917).

Two of these are worth a flag on date alone, not on citation status:

• US 99,266 (Jan 25, 1870) and US 103,989 (June 7, 1870) — both titled "Improvement in liquid-meters," both predating the original US 109,372 (Nov 22, 1870). On their face these are the correct vintage to be § 102(b)-type printed publications against the original, and they share RE5806's title. I have not retrieved their disclosures and therefore make no anticipation finding. They are similarity outputs, not cited art; I flag them only as the highest-value next search targets.
• Most of the rest postdate the original patent (1872–1919) and are, at best, context for how the art developed; several (e.g., US 127,126, 1872) postdate even the 1874 reissue filing.

For completeness, the same machine list attached to the original US 109,372 differs and includes US213944A, US144747A, US13320A ("Water-meter"), US141394A, US87448A, US118392A ("Improvement in piston-valves for fluid-meters and motors"), US64166A and US53373A. Same caution: similarity, not citation.

Consolidated claim-by-claim anticipation table

Explicit uncertainty and cautions

1. There is no patent citation list for RE5806. Neither the supplied authoritative full text nor my searches surface "References Cited" data. Anything presenting such a list for this patent is editorial reconstruction.
2. The 1869 Ball & Fitts patent number is unverified. I have its date (20 July 1869), its inventors, and the Court's description of its subject matter — nothing more. I deliberately did not infer a number. This is the single most important gap, because that reference is the strongest validity threat to Claims 1 and 2.
3. The "various older patents" pleaded by the defendants are unnamed in the opinion and could not be retrieved. Do not treat my Ericsson/Sickels/Ball-1868 entries as that list; they are separately sourced.
4. § 102 is the wrong statute for an 1874 patent. The 1870 Patent Act governed. My § 102 labels are a requested convenience and should not be quoted as if contemporaneous.
5. The Ericsson reference is cited by name and year in the opinion, not by number. I matched it to US 7,869 on the strength of the 1851 date, the "water-meter with slide valves" description, and the "stops + joint having sufficient play + crank-shaft" claim language in the retrieved text — an identification I regard as strong but circumstantial; the Court itself never states the number.
6. The Sickels and Ball-1868 patents are not shown to have been cited. I labeled them as search-surfaced context, not as of-record art.
7. Consistency with the earlier sections: nothing here contradicts the prior findings. The "5806 vs 5808" discrepancy (SooperKanoon's syllabus) is unaffected — the opinion I relied on consistently says 5806, and my searches again returned 5806 across Cornell LII, Justia, CourtListener, WorldLII, law.resource.org, the LOC U.S. Reports PDF (usrep101332), and vLex (25 L.Ed. 1024).
8. Tool limitation: I exhausted my search-step budget before I could retrieve the disclosures of US 99,266 / US 103,989 or confirm whether the Google Patents RE5806 page renders any "Cited By" annex. Those two items are the highest-value unresolved threads.

I'll ground the prior-art references before analyzing. Note: this is an 1874 reissue, so I need to check dates carefully — much of the "Similar Documents" list on the Google Patents page post-dates it.

Key find: Ericsson's 1851 water-meter patent is US Patent No. 7,869. Let me pull its full text plus Desper's patent and the earlier Ball & Fitts 1869 patent.

Obviousness Analysis of U.S. Patent No. RE5806 under 35 U.S.C. § 103

(Builds on the earlier sections; I do not restate the claim table, bibliographic data, or the Union Water-Meter v. Desper discussion, except where they feed directly into the validity analysis.)

1. Threshold problems with the question as framed

1.1 The statute is anachronistic. RE5806 was granted March 24, 1874. 35 U.S.C. § 103 was enacted in 1952 as a codification of the "invention" requirement of Hotchkiss v. Greenwood, 52 U.S. 248 (1851). In 1874 the governing provision was § 24 of the Patent Act of 1870, which denied a patent where the thing claimed had been "patented or described in some printed publication prior to his supposed invention or discovery thereof." I therefore apply the modern Graham v. John Deere, 383 U.S. 1 (1966) framework retrospectively, as a structured way of asking the 1874 question: did the difference between the claims and the prior art require more ingenuity than that of an ordinary skilled mechanic?

1.2 The critical date controls which of the page's "Similar Documents" are even available. This is the single most important point and it is usually gotten wrong for this patent. Google Patents lists the prior-art date as 1874-02-26 (the reissue filing date). That date is wrong for the claims as issued. The reissue specification and claims are, on their face, the same disclosure as original patent No. 109,372 (Nov. 22, 1870) — and the original 109,372's own text states that "the slots in the connecting-rods, in which crank-pins move … in connection with stops at the end of the cylinders … constitute the peculiar features of this invention" (https://patentimages.storage.googleapis.com/4f/af/0e/a64aad84b50ab4/[US109372](/patent/US109372).pdf). The reissue claims therefore carry the 1870 effective date, not 1874.

Consequence: the overwhelming majority of the "Similar Documents" list is not prior art at all. The following all post-date November 22, 1870 and are unavailable:

Note in particular that Desper's own patent No. 144,747 cannot be used to invalidate the claims it was held not to infringe. Whatever else is true, the Desper reference is a 1873 document and the claims date from 1870.

Available art is limited to the pre-1870 entries: US64166A (1867-04-23), US44901A (1864-11-01), US54906A (1866-05-22), US99266A (1870-01-25, "Improvement in liquid-meters"), US103989A (1870-06-07, same title), USRE4040E (1870-06-21), plus two references identified in the record but not in the page's Similar Documents list:

• John Ericsson, U.S. Patent No. 7,869 (1851) — the reference the Supreme Court itself identified. Google Patents URL: https://patents.google.com/patent/US7869. (The printed copy shows the number as "7,860" in the OCR page header of the PDF at https://patentimages.storage.googleapis.com/4e/2d/7a/45d0e89b3d6b40/US7869.pdf; I flag this rather than silently correcting it.)
• The earlier Ball & Fitts patent of July 20, 1869, repeatedly referred to in the record but whose number I could not verify.

1.3 The fork in the road. If the reissue claims are not entitled to the 1870 date (the same-invention defense Desper pleaded, 101 U.S. at 333), then the reissue is invalid as containing new matter under the reissue statute — and, on that alternative footing, Desper 144,747 and Morley US137,559 (filed Nov. 4, 1872) become available. Either way the claims are exposed. The analysis below uses the 1870 date, i.e., the most favorable assumption for the patentee, and still finds the claims obvious.

1.4 Date inconsistency in the instructions. The task states "Current Date: April 26, 2026"; the systems context supplied to me gives 2026-09-27, which is also the fetch date of the full text. I note the discrepancy rather than resolving it; nothing in the analysis turns on it.

2. Person having ordinary skill in the art (PHOSITA), c. 1870

A competent mechanic, millwright, or patent-office model maker with several years' experience in reciprocating hydraulic machinery — pumps, water motors, and positive-displacement fluid meters — familiar with (i) crank-and-slot (Scotch-yoke) motion conversion, (ii) slide and rotary valve gearing, (iii) bevel and spur gear trains for driving registers and valves, and (iv) the accuracy problem created by lost motion and wear in crank pins, journals, and bearings.

3. Claim-element mapping

4. The combinations that render the claims obvious

Ground 1 (primary): Ericsson US 7,869 alone or in view of any rotary-valve meter — claims 3, 5, 7, 8, and 4

Ericsson's 1851 meter discloses every element of claim 3 and claim 4 except the rotary valve, and it discloses them for the identical purpose: accurate measurement. Ericsson states the problem in terms that RE5806's specification reproduces almost word for word: "it is necessary after the piston has completed its stroke that it should remain at rest until the valve shall have been shifted … The motion of the valve to effect this change is obtained from the crank shaft which is then impelled, during the repose of one piston, by the descending motion of the other piston, the play given to the connection of each piston with the crank pin admitting of the rest of one piston at the end of each stroke." RE5806's stated object is the same: "in no case allowing the one double-acting piston to force the other to move while its valve-ports are closed," "obtained through the agency of the widened slot."

Ericsson also independently supplies the reason for making the stops adjustable, which is the only element the Supreme Court identified as newly added in 1870 ("My invention … consists in determining the range of motion of the pistons by means of stops … instead of doing this by the cranks, … for the least wear of either the crank pin, or the journals of the shaft, or the boxes in which these work, or the slightest change in the position of the cylinders … would of necessity vary the amount of water discharged at each stroke"). And RE5806's own specification says the adjustment "is effected by interposing a greater or less number of washers" (https://patents.google.com/patent/[USRE5806](/patent/USRE5806)/en) — i.e., the patentee's adjusting stop is Ericsson's washer (y). Claim 5 (rod + slot wider than the wrist + adjusting stops) reads directly on Ericsson.

Claim 7 (rod with a single crank and crank-pin) is squarely disclosed by Ericsson's yoke-slot-and-crank-pin, and claim 8's "concavity on each side at or near its middle" is a slot-profile refinement of Ericsson's oversized slot, which the patentee's own specification concedes is an alternative to "a slot … made of an equal width throughout its length."

Ground 2 (strongest doctrinal combination, and the one that maps exactly onto the record): Ball & Fitts, July 20, 1869 + Ericsson US 7,869 — claims 1, 2, 3, 4, 6

The Supreme Court held that "the rotary valve, and the combination of the cylinders, piston-rods, crank-shaft, and rotary valve were the subjects of a previous patent granted to Ball and Fitts on the 20th of July, 1869. The only additional elements in the present patent are the adjusting stops and the rectangular position of the slots in the piston-rods" (101 U.S. at 334). That judicial finding is, in substance, an unchallenged admission of the entire § 103 case: the 1869 patent supplies the rotary valve, the cylinders, the piston rods, and the crank-shaft combination (claims 1, 2 and the bulk of claims 3, 4); Ericsson supplies the two "additional elements" — piston-rod slots of a width greater than the crank pin, disposed at right angles to the path of motion, and end stops that fix the stroke for accurate measurement.

Claim 6's "each of the pistons may be independently adjusted without interfering with the motion of the other" is the inherent and expected result of Ericsson's two crank pins set "at right angles" with per-cylinder stop washers: adjusting one cylinder's stroke has no effect on the other's, because each rod engages its own pin in its own slot.

Ground 3: Ericsson US 7,869 + any pre-1870 rotary-valve liquid meter (candidate: US99266A and/or US103989A, both titled "Improvement in liquid-meters," 1870) — claims 1 and 2

Claims 1 and 2 recite no stops and no widened slot. They are the barest combination of (rotary valve + cylinder(s) + double-acting piston(s) + angled single cam-slot + crank-shaft). Claims 1 and 2 are therefore the weakest claims, not the strongest: on the record's own account the rotary-valve architecture itself was old, and the Court noted "the patent in question does not cover any of the separate parts of the meter, it being conceded that these were all known and used before the application for the patent" (101 U.S. at 333).

5. Motivation to combine (the KSR / Graham inquiry)

1. Same field, same problem, same solution. All references are positive-displacement fluid meters or their close hydraulic analogues. Ericsson articulates precisely the problem RE5806 claims to solve (accurate discrete measurement; valve reversal across dead-center during one piston's repose) and proposes precisely RE5806's mechanism (slot play wider than the pin). KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 417–21 (2007) (a known technique addressing a known problem, in the same field, is obvious).
2. The patentee's own specification supplies the motivation to substitute the valve. RE5806 states the "rotary valve itself may be of any suitable construction," that the eduction ports "are not shown in the drawings, nor is such deemed necessary," and that the valve "may be of any suitable construction so long as it is necessary ports through the channels … supply the liquid to and discharge it from the cylinders when measured." A patentee's express disclaimer of any criticality in a component is an invitation under § 103 to substitute the known alternative.
3. Substitution of a rotary valve for a slide valve is a predictable, art-recognized substitution. Both were standard porting devices for reciprocating hydraulic machines; the substitution changes no principle of operation, only the port-sealing geometry.
4. Making fixed stops adjustable is the definition of an obvious improvement. Ericsson used a washer and a shoulder; RE5806's adjustment is by adding or removing washers. A screw-threaded, lockable version of the same washer stack is a routine mechanical expedient, and the motivation is supplied by Ericsson's own accuracy rationale (wear and cylinder misalignment "would of necessity vary the amount of water discharged at each stroke").
5. The 90° crank offset and the widened slot are mutually reinforcing, and both were known. Ericsson: pins "at right angles so that when one passes the dead point the other will be at the full length of its leverage." RE5806: cranks "set at an angle of ninety degrees to the other, or thereabout." Identical.
6. No unexpected results are asserted for the differences. The stated advantages (uniform motion, re-enforcement of the crank at the point where the cam-slot exerts least power) are the same advantages Ericsson attributes to the same structure.
7. The claimed "concavity" is a predictable design choice. RE5806's specification frames the cupped slot as an alternative to a slot "of an equal width throughout its length," chosen to trade dead-center clearance against earlier re-engagement — a timing/geometry trade-off within the routine skill of a mechanic, with no data showing criticality.

6. The best (still weak) non-obviousness arguments

• Claim 8's cupped slot (concavity on each side near the middle). The strongest candidate for survival, because it is the most specific geometry and Ericsson's slot is described only as "wider than the pin." But the specification's own framing as an alternative to a uniformly widened slot, and the absence of any asserted unexpected result, make this a change in degree, not in kind.
• Secondary considerations. There is a plausible long-felt-need/commercial-success story (large-scale municipal water metering; litigation by the Union Water-Meter Company), but the record I retrieved contains no evidence of nexus to the claimed differences (stops and slot geometry) rather than to the admittedly old rotary-valve architecture. Under Graham, that evidence would have to be developed; I cannot supply it from the sources searched.
• Narrow claim-7 wording. The OCR-corrupted phrasing of claim 7 (noted in the earlier sections) might, at the margin, make a reference-reading argument awkward — but its substance (rod + single crank + crank pin) reads directly on Ericsson's yoke.

7. Bottom line

On the assumption most favorable to the patentee (1870 effective date, so that Desper 144,747 and Morley 137,559 are unavailable), claims 1–8 are all vulnerable under § 103:

• Claims 1 and 2 — obvious over the 1869 Ball & Fitts rotary-valve meter in view of Ericsson US 7,869 (or over any pre-1870 rotary-valve liquid meter, e.g., US99266A / US103989A, in view of Ericsson).
• Claims 3, 4, 5 and 7 — obvious over Ericsson US 7,869, which discloses the angled single slot, the slot wider than the crank-wrist permitting dead-center passage, the 90°-offset two-crank shaft driving the valve during one piston's repose, and end stops (washers/shoulders) for measurement accuracy — with the rotary valve supplied by the 1869 Ball & Fitts patent or ordinary knowledge.
• Claim 6 — obvious over the same combination; independent adjustability is inherent in per-cylinder stops with two 90°-offset crank pins and separate slots.
• Claim 8 — obvious as a slot-profile refinement, absent evidence of criticality.

The Court's observation that "the patent, as it stands, occupies very narrow ground" was made in the infringement context, but it is equally an invalidity observation: the patentee conceded every separate part was known, and the Court itself identified only two elements as new over the patentees' own 1869 patent — both of which appear in Ericsson's 1851 meter.

8. Explicit uncertainties

1. I could not retrieve the full text of US144747A (Desper) or the Ball & Fitts July 20, 1869 patent number (search budget exhausted); the 1869 patent is described only through the Supreme Court's characterization, which is second-hand but authoritative.
2. I could not verify the contents of US99266A, US103989A, US64166A, US44901A, US54906A, or USRE4040E. Ground 3 accordingly rests on titles and dates, not on verified disclosures, and is stated as a candidate ground.
3. The Ericsson patent number appears as 7,869 in the Google Patents URL and as "7,860" in the OCR page header of the printed copy; both readings are reported above rather than one being silently preferred.
4. As flagged previously, the SooperKanoon syllabus renders the reissue as "No. 5808" while its own body and every primary source give 5806; I report it literally and do not treat it as a second patent.
5. My § 103 analysis is a retrospective application of a 1952 statute; the contemporaneous standard was Hotchkiss's "invention" inquiry, and a 19th-century court might have reached a different result on the cupped-slot claim in particular.