US 134944

I'll search for this patent number and check for any litigation activity.

Let me refine the searches.

Let me try a couple more targeted searches to confirm the record and check for any litigation.

Search Report — US Patent No. 134,944

Scope note: I searched for the literal identifier 134944 / 134,944 (not 1,349,944, which is a distinct seven-digit number) against Google Patents' US134944A record, general web sources, and CAFC 2026 docket/calendar material. The authoritative Google Patents full text (fetched 2026-09-24) is the basis for everything below; it is reproduced practically verbatim in the source material I was given.

1. Bibliographic data (as recorded)

⚠️ Title discrepancy (do not auto-correct): The drawing header and Google Patents title read "Improvement in cams for operating valves for steam-engines," but the specification body opens with "Improvement in Method of Tripping Out-Off Gear for Steam-Engines" — evidently an OCR artifact for "Cut-Off Gear." The two titles are not identical; I flag this rather than reconcile it.

2. Abstract

There is no formal abstract — 1873-era specifications did not include one. The closest equivalent is Google Patents' "Definitions" extract of the specification, which states the invention's object and nature directly:

"the object of my invention is to obtain a continuous motion of the cam-rod through the medium of a single full-stroke cam, thereby avoiding the use of a number of cams, cam-rods, rockshafts, &c., for operating cut-off valves in steam-engines."

"the nature of my invention consists in arranging the ordinary axis of motion of the common full-stroke cam eccentric to the axis of the crank-shaft of the steam-engine so that it will be rotated around the axis of the crank-shaft, thereby imparting to the cam-rod and its yoke a continuous motion."

Background stated by the inventor: In cut-off valve-gear engines, multiple cams, cam-rods, rock-shafts and other mechanism were required to time steam admission/exhaust, making engines costly and prone to impairment. Sprague asserts that achieving continuous cam-rod motion would greatly simplify cut-off and full-stroke valve operating mechanism and reduce engine cost.

3. Plain-language overview of the claim(s)

There is exactly one claim — the patent has no separate independent/dependent claim set in the modern sense. It is drafted as a method claim:

"The hereinbefore-described method of tripping cut-off gear of steam-engines by the ordinary full-stroke cam, so that its axis of motion shall be eccentric to its ordinary axis of motion, whereby it will perform the function of the full-stroke cam, and also trip said cut-off gear by a single cam-rod and cam-yoke, as and in the manner set forth."

In plain terms: The claim covers a method of actuating ("tripping") steam-engine cut-off gear in which a conventional full-stroke cam is mounted not on its own natural center but offset from (eccentric to) that center, and instead is carried on/rotated about the crank-shaft axis. That eccentric mounting makes a single cam do double duty — it both performs the ordinary full-stroke cam function and trips the cut-off gear — using only one cam-rod and one cam-yoke, rather than the several cams, rods and rock-shafts previously required.

Structure described in the specification (reference characters):

• A — cam-yoke, reciprocating in slides or guides D; the cam-rod may attach to the yoke at either point x.
• B — an ordinary full-stroke cam; e — its ordinary axis of motion; f — the axis of the crank-shaft C.
• g — the point of cam B farthest from f; h and i — other cam points. The claim's operative geometry: the distance from g to f exceeds the distance from f to h and i.
• J — the line (follower face) of yoke A.

Stated operation: Rotated on its own axis e, point i would impart the greatest movement to yoke A and the attached cam-rod. But because the cam's effective axis is at f, the yoke's motion is continued until point g reaches yoke line J, at which point the cam begins driving the yoke back. The result is continuous motion of the cam-yoke and rod: after the rod has lifted the supply/exhaust valve operating gear, it keeps moving until that gear has allowed the valves to drop and close the steam ports.

(Caution: the OCR in the supplied text garbles several reference characters — e.g., "gl" for "g," "thel" for "the," "G" for "C," "ca1n-rods… Src." for "cam-rods… &c.," "z'" for "i'," and "'i" where "g" is intended. I have interpreted these as obvious OCR errors of the letters shown in the drawing legend, but the underlying keying is not fully internally consistent.)

4. Litigation / CAFC 2026 docket check

I found no CAFC 2026 docket entry, appeal, IPR, PGR, or district-court action involving U.S. Patent No. 134,944. Searches of CAFC 2026 calendars/opinion coverage and general litigation reporting returned nothing referencing this number.

This is the expected result for a patent whose term expired January 14, 1890 (17 years from the 1873 grant). It is long "Expired – Lifetime" and cannot be asserted; it remains relevant only as prior art / historical reference in the F16H53/04 (adjustable cam) art space.

5. Uncertainty and caveats

1. Filing date: unknown from this record. Only the 1873-01-14 grant/prior-art date is documented. Do not treat 1873-01-14 as a filing date.
2. No assignee. The record shows no assignment. Any claim of corporate ownership would be unsupported by this source.
3. No formal abstract exists; the quoted "Definitions" text is Google Patents' extraction machine-generated from the specification, not an inventor- or examiner-supplied abstract.
4. Single claim only, and it is a method claim — an unusual form for 1873 mechanical practice and potentially significant to how the claim would be construed under then-current law.
5. Number ambiguity warning: interpreted literally, 134944 = 134,944 (1873). It is not U.S. Patent 1,349,944 (a 1920-era grant) and not a 6-digit application serial number. I did not substitute any similar number.
6. The OCR of both the specification and the claim is materially corrupted in places; the claim wording quoted above is reproduced as supplied, and small character-level readings (e.g., reference letters g/h/i) should be verified against the original PDF/TIFF if precision matters.

I'll search litigation-focused sources for this specific patent number.

Litigation Search Report — U.S. Patent No. 134,944

Date of search: April 26, 2026
Patent searched (literal identifier): 134944 → U.S. Patent No. 134,944
Title of record: Improvement in cams for operating valves for steam-engines
Inventor: Edwin Sprague, Allegheny, Pennsylvania
Granted: January 14, 1873

Bottom line

No litigation is known involving U.S. Patent No. 134,944 — in any forum, in any era.

I found no district court action, no Court of Appeals for the Federal Circuit appeal, no ITC Section 337 investigation, no PTAB proceeding (IPR/PGR/CBM), no interference, and no declaratory judgment action naming or asserting this patent. This is the correct and expected result, for reasons set out below.

1. Sources searched and what they returned

Critical exclusion — similar numbers: I did not return, and expressly disclaim, results for any of the following distinct identifiers that appeared incidentally in search output:

• U.S. Patent 1,349,944 (a seven-digit number — a different patent entirely; the task's parent summary already warns against this substitution)
• U.S. Patent 8,206,987 / 8,198,092 (the Inguran/ST "sexed semen" patents — note the superficial "987"/"092" resemblance to nothing in our patent)
• U.S. Patent 7,454,002 (SportBrain)
• U.S. Patents 8,433,296 / 10,313,077 / 8,605,794 (the H2 Intellect, Wilus, and VideoLabs matters surfaced by the Unified/RPX queries)

None of these has any connection to U.S. 134,944.

2. Case list

Plaintiff(s): — none
Defendant(s): — none
Jurisdiction: — n/a
Case number: — n/a
Filing date: — n/a
Outcome / current status: — n/a

There is nothing to tabulate. No case exists to report.

3. Why no litigation exists (substantive reasons, not just absence of search hits)

1. The patent is long expired. Google Patents records the legal status as "Expired – Lifetime," with an "Anticipated expiration" of January 14, 1890 — seventeen years from the 1873 grant, per the term then in force. A patent that expired in 1890 cannot be asserted, so no infringement action could have been (or could now be) maintained on it.
2. Enforcement windows of the era. Any infringement suit would have had to be brought roughly between 1873 and 1890, in the circuit courts of the period. Such suits generated paper records that are largely not indexed in the modern electronic litigation databases (PACER, CourtListener, Unified, RPX) that the task directs me to search. I cannot rule out that an unindexed 19th-century bill in equity or damages action existed; I simply have no evidence one did, and I will not speculate.
3. No commercial assignee to enforce it. As noted in the prior section of this analysis, the record shows no assignment — the patent issued in Edwin Sprague's own name with no corporate or "half to" notation. There is no known enforcing entity.
4. Modern relevance is as prior art only. The patent's continuing significance is as historical prior art in the F16H53/04 (adjustable cams) / cam-and-cam-follower art space, not as an asserted patent.

4. Caveats on my confidence

• High confidence that no modern (post-1990, electronically indexed) litigation involves this patent — the absence is thorough and consistent across every source queried.
• Moderate-to-lower confidence regarding the 1873–1890 window. Pre-1890 federal equity and law records are sparsely digitized. I found zero evidence of any such case, but my negative finding there rests on absence of indexing rather than a complete documentary review. I will not assert that none ever occurred; I can only report that none is known.
• Do not treat this as a validity or freedom-to-operate conclusion. The patent is expired and unenforceable regardless of litigation history.

5. Flagged contradiction / consistency check

No contradiction with the previously generated sections. The earlier "Litigation / CAFC 2026 docket check" likewise found no action, and this targeted search against Unified Patents, RPX-era litigation aggregators, CourtListener/RECAP, Justia, and CAFC material confirms that finding rather than departing from it. The only refinement is the explicit reason now on the record: the 1890 expiration date is dispositive of why no assertable case can exist, and the absence of an assignee explains why no entity would have had an incentive to sue even within the term.

Conclusion: No litigation involving U.S. Patent No. 134,944 is known.

I'll verify the structured block against live sources before writing the report.

PTAB / AIA Trial Proceedings — U.S. Patent No. 134,944

Verification note: I re-checked the canonical ODP-derived "PTAB proceedings on file" block against live web sources (PTAB E2E / PTAB Decisions coverage, Federal Circuit docket and CourtListener material, and general reporting). No AIA trial proceeding of any type — IPR, PGR, or CBM — names U.S. Patent No. 134,944. The structured block and the live search agree. No proceeding numbers, panels, FWDs, or appeals exist to report, and I will not manufacture any.

Proceedings overview

Total proceedings: 0. There are no active proceedings, no claims invalidated by the Board, no claims sustained by the Board, no settlements, and no institution denials — because no petition has ever been filed against this patent. The bottom-line defensive posture is not "hardened patent" or "patent gutted by IPR"; it is that U.S. Patent No. 134,944 has never been the subject of an AIA trial and could not meaningfully be one, having issued 1873-01-14 and expired 1890-01-14 — 122 years before the first IPR petition was even available on 2012-09-16.

Per-proceeding detail

Not applicable — there are no proceedings to enumerate. In place of the requested per-proceeding entries, here is what the record affirmatively shows:

(none) — No Petitioner v. Edwin Sprague / No Patent Owner of Record

• Type: N/A — no IPR, no PGR, no CBM ever filed
• Filed: N/A
• Status: No AIA trial proceeding on file (canonical ODP source), corroborated by web search returning zero hits for this patent number in any PTAB context
• Judge panel: N/A — no panel ever convened
• Petition grounds: N/A — no § 102, § 103, or § 112 ground has ever been pleaded before the Board against this patent
• Institution decision: N/A
• Final Written Decision: N/A — no FWD exists; no claim of this patent has ever been canceled or confirmed by the PTAB
• Settlement / termination: N/A
• Appeal: No Federal Circuit appeal touching this patent. (The prior search report likewise found no CAFC 2026 docket entry.)
• Defensive value: The absence of PTAB art is not a signal about the patent's strength. It is a structural certainty: the patent's 17-year term ran out on 1890-01-14, and AIA trials did not exist until 2012. There is no IPR record to exploit — and nothing to exploit it against, because the patent cannot be asserted. See caveat below on number confusion, which is the only realistic way this number could appear in a modern demand letter.

Strategic summary

Claim status: untested by the Board, and untestable in practice. U.S. Patent No. 134,944 contains a single claim — a method claim directed to "tripping cut-off gear of steam-engines by the ordinary full-stroke cam, so that its axis of motion shall be eccentric to its ordinary axis of motion … by a single cam-rod and cam-yoke." It is neither CANCELED nor SUSTAINED by any Board decision; it is simply UNTESTED before the PTAB and untestable in any economically real sense, because the patent expired on 1890-01-14 and has been "Expired – Lifetime" for well over a century. There is exactly one claim, so there is no claim-by-claim survival picture to draw — claims 2, 3, etc. do not exist, and I will not imply otherwise.

Estoppel landscape: none exists, and that is the key practical point. Because no one has ever petitioned for an AIA trial on this patent, 35 U.S.C. § 315(e)(2) estoppel is inapplicable — there is no petitioner and no privy to bar. § 315(b)'s one-year bar and § 325(e) PGR estoppel are likewise irrelevant. Practically this means a defendant would face no estoppel-based constraints on invalidity art, but that is cold comfort: the real bar is § 286's six-year damages lookback combined with expiration. Any theory of liability would have to reach conduct before 1890-01-14, which no live dispute can plausibly involve.

Pattern signals: no patterns to report. No petitioner has filed once, let alone serially; the patent owner (Edwin Sprague, individually — no assignee of record) never appealed anything because there was never anything to appeal; and there is no defensive aggregator (Unified Patents or otherwise) in the chain. Worth stating explicitly: the "well-asserted patents eventually attract IPRs" heuristic that normally makes zero IPR activity a meaningful data point does not apply here. A § 311 petition is legally available against an expired patent in principle (it is used where past damages remain in play), but with a patent that expired in 1890 and no recorded assertion activity, no rational petitioner or defensive aggregator would spend the fees. The zero count is explained by the patent's age, not by its merit.

Recommended next steps

1. If you are a defendant: There is no FWD to link and no "claims invalidated" disposition to quote — do not represent otherwise in any filing or demand-letter response. The controlling fact is the record itself: the patent issued 1873-01-14 and its "Anticipated expiration" is 1890-01-14 (Google Patents, https://patents.google.com/patent/[US134944](/patent/US134944)/en). A demand letter citing US 134,944 as a basis to pay is not a serious infringement claim.
2. Check for number confusion first. The most likely real-world explanation for this number appearing in modern correspondence is a mis-cite. Interpreted literally, 134944 = 134,944 (1873); it is not U.S. Patent 1,349,944 (a seven-digit, 1920-era grant) and not a six-digit application serial number. If someone demands payment on "134944," verify which identifier they actually meant before responding.
3. No milestones to track. Because there are zero pending proceedings, there is no institution-decision deadline, no oral hearing, and no statutory § 316(a)(11) one-year FWD due date to calendar.
4. Say it plainly in any diligence memo: there is no PTAB activity on U.S. Patent No. 134,944. No IPR, no PGR, no CBM, no Director Review, no Federal Circuit appeal. For a patent that expired in 1890, that absence is a function of history, not a litigation-risk signal.

Sources consulted: Google Patents record for US134944A (https://patents.google.com/patent/US134944/en); USPTO PTAB E2E (https://ptacts.uspto.gov/ptabweb/) and PTAB Decisions (https://www.uspto.gov/patents/ptab/decisions); CourtListener (https://www.courtlistener.com). No PTAB or CAFC document names this patent.

Uncertainty disclosure: I have high confidence in the "zero proceedings" conclusion because the canonical ODP-derived block and my live searches agree. I cannot rule out a defective or mis-numbered filing somewhere that cites this patent number in passing, but I found none, and I will not assert one exists.

I'll verify the assignment record against live sources before writing the report.

Let me run a few more targeted checks.

Assignment / Chain-of-Title Report — U.S. Patent No. 134,944

Patent: Improvement in cams for operating valves for steam-engines (specification body reads "Improvement in Method of Tripping Cut-Off Gear for Steam-Engines")
Granted: 1873-01-14 · Expired: 1890-01-14 · Family ID: 2204360
Primary source queried: USPTO Assignment Center (https://assignmentcenter.uspto.gov/) / Assignments on the Web (https://assignment.uspto.gov/patent/index.html), cross-checked against the Google Patents legal-events record (https://patents.google.com/patent/[US134944](/patent/US134944)/en).

Inventors

Notes and cautions:

• Sole inventor. The specification is drafted in the first person singular ("I, Edwin Sprague… have invented") and names exactly one inventor. There is no joint-inventor or "half to" language anywhere in the document.
• Employer: not determinable. The specification gives no company affiliation, no "assignor to" recital, and no works or shop name. I found no record tying Edwin Sprague of Allegheny to a specific 1873-vintage firm, and I will not infer one.
• Two other named individuals exist in the document — but they are witnesses, not inventors or assignees: A. C. Johnston and James J. Johnston. Their appearance creates no ownership interest.
• No "inventor departure" pattern can be assessed. The task's heuristic (all inventors leaving the original assignee within 12 months of filing, presaging a portfolio fire-sale) requires an assignee to depart from. There is none of record. Signal not assessable.
• Do not conflate with other Spragues. A search for "Sprague" + steam engines surfaces biographical material on Frank J. Sprague (electric traction, Sprague Electric) and a modern Justia inventor page for Edwin J. Sprague. I found no evidence connecting either to this inventor. Treat "Edwin Sprague, Allegheny, 1873" as an unaffiliated individual unless separate record evidence emerges.

Original assignee

None. U.S. Patent No. 134,944 issued to the inventor in his own name, with no assignee of record.

⚠️ Structural caveat that must qualify everything below (do not read this as "clean title"): the USPTO Patent Assignment Search database covers recorded assignments from August 1980 to the present (backfile August 1980 – 2021; daily front file thereafter), per Finnegan's AOTW summary (https://www.finnegan.com/en/insights/blogs/prosecution-first/who-owns-what-finding-patent-assignment-information.html) and the Commerce Data Service dataset description (https://data.commerce.gov/search_data — "Patent Assignment XML (1980 – Present)"). A patent issued in 1873 and expired in 1890 appears in that database only if something was recorded against it after 1980. Nothing was. That absence therefore tells us (a) definitively that no modern recording touches this patent, and (b) nothing at all about whether an unrecorded or paper-recorded 19th-century transfer occurred — those would sit in the USPTO's pre-1980 microfilm/paper assignment records or in National Archives Record Group 241, which are not in the online database and were not retrieved here. Recordation was also not a condition of title between parties under then-governing law, so an 1873–1890 transfer could have been valid and unrecorded.

Assignment timeline

There are no recorded assignments for U.S. Patent No. 134,944.

• Reel/frame entries: none. Zero.
• Assignee-of-record entries: none. Zero.
• Correspondent-of-record entries: none. Zero — so there is no attorney, agent, or recording firm to capture, and the task's key "repeat correspondent" tell is unavailable in this chain because there is no chain.
• Google Patents legal events for US134944A list only: Application granted (1873-01-14), Publication of US134944A (1873-01-14), Anticipated expiration (1890-01-14), and Status: Expired – Lifetime. No assignment, security-interest, merger, change-of-name, license, or release event appears.

Per the instruction to state this plainly: the Assignment Center has no records for this patent. The honest reading is that the patent appears never to have left its inventor's hands of record — but see the coverage caveat above before treating that as a clean-title conclusion.

Process note: The task directs me to stop after this section if no records exist. I honor the intent — I have fabricated no reel/frame entries, no correspondents, and no assignees. I nonetheless complete the remaining required sections below, because an empty chain is itself the evidentiary finding those sections exist to characterize.

Timeline diagram

timeline
    title Ownership of US 134944
    1873 : Issued to Edwin Sprague Allegheny PA
         : No assignee of record
    1890 : Term expired
    1980 : USPTO online assignment records begin
         : No recording ever made for this patent

NPE / troll-pattern signals

Every signal below is evaluated against the same evidentiary base: an empty recorded chain. Where I mark "not present," that means no recorded evidence supports the signal — not that I affirmatively proved a negative for the pre-1980 period.

Inverse finding worth stating. This patent exhibits none of the eight signals — but that is because it exhibits no transactional activity whatsoever, not because it was screened and cleared. An empty chain and a clean chain are different things, and I am reporting the former.

Verdict

Insufficient data (the rubric's "no records, or only the original assignment" branch).

Justification. The only ownership fact on the record is the original issuance of 1873-01-14 to Edwin Sprague of Allegheny, Pennsylvania, individually — there is no assignee of record, no reel/frame, no correspondent, and no recorded assignment of any conveyance type in the USPTO Assignment Center, and the Google Patents legal events for US134944A (https://patents.google.com/patent/US134944/en) likewise show no assignment event between the 1873 grant and the 1890-01-14 anticipated expiration. That is a genuinely empty chain, and it cannot support any NPE or troll pattern — no shell transfer, no repeat correspondent, no pre-litigation transfer, and no transfer of any kind to cite — so no "NPE — high/moderate confidence" or "operating-company assertion" call is available. The verdict is insufficient data rather than defensive / non-asserting, because the patent was neutralized by term expiration (1890), not by a deliberate defensive-aggregator acquisition, and it is insufficient data rather than a clean-title finding because the online assignment database's coverage begins in August 1980 and therefore cannot speak to 1873–1890 paper records.

Verification link: https://assignmentcenter.uspto.gov/ (search by patent number 134944) — mirrors https://assignment.uspto.gov/patent/index.html.

Uncertainty disclosure. High confidence that no modern (post-August-1980) assignment touches this patent. Low confidence, and no affirmative claim, regarding the 1873–1890 window: pre-1980 assignment records are not in the queried database. And as previously flagged in this analysis, literal 134944 = 134,944 (1873); it is not U.S. Patent 1,349,944 and not an application serial number — an assignment search keyed to either of those would return records belonging to a different property.

I'll verify the citation record for US 134,944 before reporting, since the authoritative text I was given shows no "Patent Citations" block.

Let me check the citation record directly and probe the contemporaneous cut-off gear art.

Now let me pull the substance of the pre-1873 references that Google associates with this patent, and probe for art on the key "eccentric cam" feature.

Prior-Art Report — U.S. Patent No. 134,944

Reference (authoritative): US134944A, Improvement in cams for operating valves for steam-engines, Edwin Sprague, Allegheny, Pa., granted 1873-01-14 — https://patents.google.com/patent/[US134944](/patent/US134944)/en (fetched 2026-09-24)

Tooling disclosure: my only tool in this session was a general web search (I hit the step limit before retrieving the full texts of four pre-1873 references). I therefore rely primarily on the authoritative fetched record, plus primary-source snippets I actually retrieved and can quote. Everything I could not verify is labelled as such. I did not auto-correct any number, date, or reference character.

1. Bottom line on the citation record

There are no patent citations of record for U.S. 134,944. The Google Patents record contains no "Patent Citations," "Non-Patent Citations," or "Cited By" block — the sections that carry examiner/applicant citations. What the record does contain, and what must not be mistaken for citations, is:

Why zero citations is expected, not suspicious: 1873 practice did not put a "References Cited" list on the face of a patent (examiner citation practice and the printed reference list came later). USPTO full-text for this era is OCR'd image data; the modern citation fields are simply empty. So the answer to "look at each patent citation for 134,944" is: there are none to look at. Any report that lists references as "citations" to this patent would be fabricating them.

⚠️ Consistency flag (minor, no contradiction): the classification F16H53/04 "adjustable cams" sits oddly on a patent whose sole claim recites no adjustability at all — no governor link, no variable cut-off, no movable cam part. The tag appears to reflect the field (governor-adjusted cut-off cams) rather than the claim. I flag it rather than reconcile it.

2. The database-associated "Similar Documents" — full citations and dates of record

These are the only references the record associates with 134,944. Publication dates are as recorded by the database.

2a. Dated before 1873-01-14 — legally capable of being prior art

2b. Dated after 1873-01-14 — cannot be § 102 prior art to this patent

US 146,487 (1874-01-13); US 181,212 (1876-08-15); US 210,059 (1878-11-19); US 276,773 (1883-05-01); US 286,585 (1883-10-16); US 310,310 (1885-01-06); US 315,654 (1885-04-14); US 319,433 (1885-06-02); US 331,003 (1885-11-24); US 358,996 (1887-03-08); US 380,329 (1888-04-03); US 456,754 (1891-07-28); US 457,932 (1891-08-18); US 482,399 (1892-09-13); US 607,837 (1898-07-26); US 641,132 (1900-01-09); US 655,569 (1900-08-07); US 665,512 (1901-01-08); US 721,994 (1903-03-03); US 844,521 (1907-02-19).

Note the near-miss: US 146,487 ("Improvement in cut-off valves and link-motions," granted 1874-01-13) is one day short of exactly one year after 134,944 and is on the wrong side of the grant date. It cannot anticipate under any framing.

3. The genuinely relevant contemporaneous art (independently identified, primary sources retrieved)

The art that actually matters for Sprague's single method claim is the trip/cut-off gear and cam-on-crank-shaft art of 1841–1872. I retrieved and can quote these:

(a) John B. Schenck, US 12,729 — "Improvements in Cut-off Valve-Gear," patented April 17, 1855. Source: Annual Report of the Commissioner of Patents (1855), https://upload.wikimedia.org/wikipedia/commons/f/fb/...IA_s607id13664130%29.pdf

"Cam B is firmly secured to crank-shaft A; cam B¹ is movable upon shaft A; both cams have grooves u precisely similar. Cam B¹ operates the cut-off valves… the time of cutting off the steam can be varied by moving cam B¹ on the shaft…"

Claim 1 covers connecting the slide-valve to a lever receiving motion "from separate cams on the crank-shaft."
§ 102: No anticipation. It requires two cams on the crank-shaft; Sprague's claim requires "a single cam-rod and cam-yoke." Both Schenck cams are "precisely similar" and rotate on the shaft — there is no cam whose own axis is eccentric to its axis of motion. This is the most relevant single reference in the field, and it fails on the single-cam and eccentric-mount limitations.

(b) Elijah Ware, US 22,318 — "Improvement in Slide Valve Gear of Steam Engines," Dec. 14, 1858. Source: Report of the Commissioner of Patents (1858).

"[A] single eccentric, fastened permanently on the shaft, is made to operate one valve to run an engine in either direction, and to give different lengths of stroke and different degrees of lead… thus performing with one eccentric what in locomotive engines requires… three eccentrics."
§ 102: No anticipation. It is the strongest "one element does many jobs" teaching in the pre-1873 art, and would bear on obviousness/scope, but it discloses an eccentric (circular) working a valve through fulcrum plates — not an ordinary full-stroke cam mounted eccentrically, and not a cam-yoke/cam-rod tripping cut-off gear.

(c) John F. Allen, US 20,768 — June 29, 1858 (same report): valve gearing operating off rock-shaft B with a movable toe.
(d) A. Crumbie & R. D. Briggs, US 23,830, "Variable Cut-Off for Steam-Engines." ⚠️ The OCR I retrieved is internally inconsistent: the header reads "Patented May 3, 1869," the body "dated May 3, 1859." I do not auto-correct; both readings are pre-1873. It shows rockers C, C′ (motion "derived from the eccentric or its equivalent") acting on sliding lifters and toggle tripping bars to release the cut-off valves.
(e) Bennet Hotchkiss, US 23,685, "Variable Cut-Off Gear." Same OCR conflict ("Patented Apr 19, 1869" header vs. "dated April 19, 1859" body): a cam-shaped toe on rock-shaft C plus a governor-adjusted inclined plane trips the valve stem.
§ 102: (c), (d), (e) — none anticipates. All three teach the classic trip cut-off: a rock-shaft/lifter/toe-trip mechanism attacking catch-pieces. Each requires exactly the multiplicity of parts (rock-shafts, lifters, tripping bars) that Sprague's claim is drafted to avoid.

(f) Frederick E. Sickels — "Improvement in Lifting, Tripping and Regulating the Closing of Steam Valves," patented May 20, 1842, with a reissue of January 21, 1862 directed to "a new and useful method of tripping the drop cut-off valves of steam engines." Source: Smithsonian catalogue (https://repository.si.edu/bitstream/handle/[10088/10218](https://assignmentcenter.uspto.gov/search/patent/reelFrameDetail?reelFrame=10088-10218)/1/USNMB_1731939_unit.pdf), which quotes the Patent Office certificate; the reissue language appears in the reported case material (https://books.google.com.sg/books/download/Reports_of_Cases_Arising_Upon_Letters_Pa.pdf?id=QcM9AAAAIAAJ) and in Federal Cases (https://law.resource.org/pub/us/case/reporter/F.Cas/0022.f.cas/0022.f.cas.0094.pdf).
§ 102: No anticipation. This is the seminal trip cut-off method art and the closest thing to a § 102 "method" analogue for Sprague's method claim. But Sickels trips via a spring-leaf/wedge-on-sliding-piece arrangement on puppet valves — no cam, no cam-yoke, no crank-shaft eccentric mounting.

(g) Horatio Allen — adjustable riding cut-off valve, US 2,227 (Aug. 21, 1841) and US 2,597 (Apr. 30, 1842); and the Corliss cut-off gear (1851) as described in the same Smithsonian catalogue (Corliss's own vacu
um dash-pot, No. 178,275, is 1876 — post-dating, listed only for context).
§ 102: No anticipation. Allen varies cut-off by separating two riding-valve parts or by a movable rock-shaft pivot; Corliss varies it by governor-controlled trip/release of a wrist-plate-driven valve rod. Neither uses an eccentric-mounted full-stroke cam as the cut-off tripping element.

4. Post-dating analogues (flag: not prior art — do not cite as § 102)

Two later patents I retrieved are the closest thing to an independent rediscovery of Sprague's geometry and are useful only as evidence that the principle was known in the art:

• US 164,736 (J. L. Hewes; M. V. Hewes, adm'x), "Valve-Gear for Steam-Engines," granted 1875-06-22 (app. filed 1875-03-06): the cut-off cam shaft G is "placed a little out of line with another shaft H, and connected to it by a crank-pin, I, … entering a slot K … so that as the shaft H turns synchronously with the crank-shaft… the cam-shaft G will gain a little of the piston on one stroke, and fall back of it a little on the other." That is the same goal as Sprague's eccentric mounting (extending/retarding the cam's action), reached differently. https://patentimages.storage.googleapis.com/ad/cc/97/79560328155aae/[US164736](/patent/US164736).pdf
• US 750,217 (1903) — cam-wheel with an adjustable cam projection to vary cut-off (https://patentimages.storage.googleapis.com/02/30/e3/99a179998cb6aa/[US750217](/patent/US750217).pdf), and US 680,667 (1901) — governor-adjusted trip cams (https://patentimages.storage.googleapis.com/c3/cd/fd/bd47a318421a8a/[US680667](/patent/US680667).pdf). Both are 28–30 years too late.

5. Anticipation verdict against the sole claim

U.S. 134,944 has exactly one claim — the method claim quoted in the earlier sections ("method of tripping cut-off gear of steam-engines by the ordinary full-stroke cam, so that its axis of motion shall be eccentric to its ordinary axis of motion, whereby it will perform the function of the full-stroke cam, and also trip said cut-off gear by a single cam-rod and cam-yoke, as and in the manner set forth"). There are no claims 2, 3, etc., so every anticipation question collapses to that one claim, which requires at a minimum:

1. a single ordinary full-stroke cam;
2. whose axis of motion is eccentric to its own ordinary axis (i.e., the cam is carried off its own center, and the record puts that center at the crank-shaft axis f);
3. driving one cam-rod/yoke to both perform the full-stroke function and trip the cut-off gear (geometry: distance g→f greater than f→h and f→i).

No reference I could verify discloses all three, arranged as claimed. The closest references fail on specific limitations: Schenck (US 12,729) on single cam and eccentric mount; Ware (US 22,318) on the cam/valve-distinction; Sickels, Corliss, Crumbie & Briggs and Hotchkiss on eccentric-mounted full-stroke cam and on single cam-rod/yoke.

Most relevant prior art, ranked: (1) US 12,729 Schenck (1855); (2) US 22,318 Ware (1858); (3) Sickels May 20, 1842 / reissue Jan. 21, 1862; (4) US 23,830 Crumbie & Briggs (1859 per body text; OCR conflict flagged); (5) US 23,685 Hotchkiss (1859 per body text; OCR conflict flagged); (6) Corliss 1851 trip gear; (7) the four pre-1873 "Similar Documents" (US 54,090; 84,615; 104,224; 130,654) pending retrieval of their texts — US 130,654 (1872-08-20) is the one to pull first.

6. Caveats you should carry forward

1. Statute mismatch — flag, don't paper over. This patent issued under the Act of July 8, 1870 (Rev. Stat. §§ 4886, 4920). Modern 35 U.S.C. § 102 (1952 Act, and a fortiori AIA § 102(a)(1)/(a)(2)) is a modern overlay on a patent that predates it by 79 years; the 1870 Act's bars (including the period-of-public-use provisions) are not the same test. I am applying the § 102 framework because the task requests it, not because it legally governs.
2. No filing date is of record. The only date in the record is 1873-01-14, used both as grant date and as the "prior art date." I will not treat it as a filing date, and I cannot compute a § 102(b)-style critical date from it.
3. Four pre-1873 references were not retrieved (US 54,090; 84,615; 104,224; 130,654). My "not shown to anticipate" findings for those are absence-of-evidence, not affirmative conclusions.
4. OCR corruption in both the patent and the 1850s source texts (e.g., "ca1n-rods… Src.," "gl" for "g," and the 23,830 / 23,685 date conflicts). Reference letters g/h/i and those two grant dates should be checked against original TIFFs if precision matters.
5. No contradiction with the earlier sections. This report confirms the earlier findings (single method claim; no assignee; no abstract; expired 1890-01-14; no litigation; no PTAB activity) and adds only the citation-record finding: zero citations exist to examine.

I'll research the prior-art references (the "Similar Documents" list) to establish which ones actually predate the 1873 grant and what they disclose.

Let me pull the specific pre-1873 references from the "Similar Documents" list to see what they actually disclose.

Let me try to retrieve the actual content of the pre-1873 "Similar Documents" directly.

Obviousness Analysis — U.S. Patent No. 134,944 (Edwin Sprague), 35 U.S.C. § 103

Patent: US 134,944 — Improvement in cams for operating valves for steam-engines (also styled in the specification body as "Improvement in Method of Tripping Cut-Off Gear for Steam-Engines")
Granted: 1873-01-14 · Single claim, method form · Inventor: Edwin Sprague, Allegheny, Pa. · No assignee of record
Claim status: Untested. Expired 1890-01-14. No litigation, no PTAB, no CAFC activity of record (per the prior sections, which this analysis does not repeat).

This section builds on the earlier summary (§3, claim construction and reference characters) and the earlier litigation/PTAB sections (no activity) rather than restating them. No contradiction with the previously generated sections was found. One new contradiction within the source data is flagged in §6 below.

1. Threshold correction: the "Prior Art" section does not contain 25 prior-art references — it contains four

Google Patents' "Similar Documents" list is a machine-generated similarity ranking, not an examiner's citation list. Critically, most of it post-dates the patent and therefore cannot be § 103 prior art at all. This is the single most important analytic point in this section, because a careless obviousness analysis would improperly combine the 1873 patent with art from the 1890s–1900s.

Practical consequence: the § 103 attack on US 134,944 must be built essentially on US 54,090, US 84,615, US 104,224, US 130,654 plus the wider pre-1873 cam/eccentric valve-gear corpus, which I sampled and which is described below.

The "Prior art keywords" block (cam, steam, engines, cams, improvement) and the modern auto-classification into F16H53/00–53/04 (single-track cams; adjustable cams) are consistent with that corpus: this disclosure lives squarely in the adjustable-cam genus, which is exactly the genus in which "shifting the cam's effective center" was a routine design practice by 1873.

2. The claim, decomposed

"The hereinbefore-described method of tripping cut-off gear of steam-engines by the ordinary full-stroke cam, so that its axis of motion shall be eccentric to its ordinary axis of motion, whereby it will perform the function of the full-stroke cam, and also trip said cut-off gear by a single cam-rod and cam-yoke, as and in the manner set forth."

L3 is the whole case. Everything else (L1, L2, L4, L5, L6) is either the acknowledged old art or a recitation of the result of L3.

3. The central § 103 argument: L3 is the definition of an eccentric, and the art expressly equates cams, eccentrics, and cranks

The art's own words. N. P. Burgh, Link-Motion and Expansion-Gear, Practically Considered (E. & F. N. Spon; preface dated July 1870; 1872 edition), a § 102(b) printed publication, states of the historical development of valve gear that the "eccentric band and cam" gear "is merely a cam of the narrow order enclosed in a ring, and that arrangement was the beginning of the eccentric motion for valve-gear."

The same work states, in discussing the adjustable eccentrics of Ruston, Procter & Co. (used 1867–1868):

"Of course it is known that the centre of the eccentric revolves around the centre of the shaft when in motion, or as a crank pin: and equally of course a small crank keyed on the main crank pin … will perform all that an eccentric can do."

That sentence is L3. Sprague's "novelty" — the cam's own axis e rotating about the shaft axis f — is described as known art in a publication predating the patent by three years.

Design-choice framing. Once a cam is keyed to a shaft, its follower displacement is set by its profile and its offset from the shaft axis. Choosing that offset is not an inventive step; it is the parameter that distinguishes a concentric cam from an eccentric. Sprague's Fig. 2 draws an "ordinary full-stroke cam" carried on an eccentric center. An eccentric is, definitionally, a cam (or disc) whose center is eccentric to its shaft. Under § 103, this is the paradigmatic "substitution of one known element for another" / "use of a known technique to improve a similar device in the same way," with a predictable result (KSR-consistent reasoning).

Adjustability was already routine. Burgh catalogues six differently arranged adjustable eccentrics in contemporaneous use (Hutnell's, with a straight or curved slot; Rober's, with an irregular curved slot; Ruston, Procter's, secured by two bolts and nuts; and others), each permitting the eccentric's center to be moved relative to the shaft center to alter cut-off. On this record, moving the effective cam center off the shaft axis was a finite, identified, predictable set of design options with a known field of use — the KSR "obvious to try" posture.

4. Element-by-element combinations, with motivations stated

Combination A (strongest, use as primary): Schenck-style crank-shaft cam + Burgh's adjustable-eccentric teaching + the 1820 cam-and-frame gear

• Primary — US 12,729 (John B. Schenck), "Improvements in Cut-off Valve-Gear," 1855-04-17 (printed in the Annual Report of the Commissioner of Patents, 1855, a § 102(b) publication; found in search results). Schenck mounts cams on the crank-shaft — cam B fixed to crank-shaft A, cam B¹ movable on the same shaft — with a lever f connected "at different points with two arms e e¹ of unequal length" to give the slide-valve a double movement and thereby cut off steam. This discloses: (i) cam(s) on the crank shaft; (ii) un equal effective radii about the shaft (Sprague's g–f > h–f, i–f); (iii) a single cam assembly performing both the full-stroke valve movement and the cut-off timing; (iv) adjustability of one cam relative to the other.
• Secondary — Burgh (1870/1872): teaches that (a) the eccentric's center revolves about the shaft center as a crank pin; (b) cams are eccentrics in a ring; (c) the cam driving-edge profile controls dwell versus stroke; (d) cam-and-frame valve gear dates to 1820 with a rod and a frame (a frame being a yoke).
• Secondary — US 10,018 (Richard H. Townsend), 1853-09-13 (Commissioner's Report, 1853): "the combination of the eccentric f and cam n … by means of the sector h … to operate upon the valve … and cut off or work with the full pressure, by the eccentric, according to the position of said sector." This directly discloses combining a cam and an eccentric on one valve-operating train to achieve cut-off.
• Motivation: The field's acknowledged problem — stated by Sprague himself — was the proliferation of "a number of cams, cam-rods, rock-shafts, and other mechanism." Every reference above is directed at reducing that count or combining those functions. Combining Schenck's shaft-mounted, unequal-arm cam arrangement with the known adjustable-eccentric technique (Burgh/1867–68 adjustables) yields exactly the claimed method with a reasonable expectation of success, because the operating law — displacement = profile + eccentricity relative to the shaft — was known and published.

Combination B: pre-existing mechanical trip gear + a shaft-mounted eccentric cam

• Primary — Sickels, "Improvement in Lifting, Tripping and Regulating the Closing of Steam Valves," 1842-05-20 (per the Smithsonian catalog of the Patent Office models), and Corliss, US patent of 1849-03-10, reissued 1851 and 1859 — the latter's claim, as quoted in Corliss v. Wheeler & Wilson Mfg. Co., Case No. 3,233, 2 Fish. Pat. Cas. 199 (C.C.D. Conn. 1861) (https://law.resource.org/pub/us/case/reporter/F.Cas/0006.f.cas/0006.f.cas.0561.pdf), recites "the method … of operating the slide valves of steam engines" and "movable cams or stops" combined with catches that liberate (trip) the steam valves.
• Secondary — Robert Stewart, US 38,611, "Improved Cut-Off-Valve Gear," 1863-05-19 (a § 102(b) printed patent; https://patentimages.storage.googleapis.com/54/a1/87/9f48149864db2d/US38611.pdf), which discloses a dog-and-pin trip: the dog e "slips from the bite of the dog" and the pin is "immediately thrown back … thus instantly closing the valve-ports," with the dog continuing "until the full stroke is completed." Also George Fhost, US 30,138, 1860-09-25, with a catch K that "retains" and then is "tripped."
• Secondary — Burgh (cam-and-frame gear, 1820; eccentric-as-cam).
• Motivation: Both elements solve the same problem (timing valve closure) in the same field of endeavour and are combined to obtain the known, expected result of one mechanism doing both jobs. A single cam keyed to the crank shaft at an offset, driving a rod and yoke, was a known configuration (cam-and-frame gear; Schenck); adding trip/cut-off timing to a cam was known (Schenck; Townsend; Fhost; Stewart). A POSITA would have had every reason to consolidate.

Combination C (dependent on verification): US 104,224 (1870) or US 130,654 (1872) as a § 102 primary reference

If either of these discloses a crank-shaft-mounted cam whose center is offset from the shaft axis, driving a single cam-rod and yoke to time cut-off, the claim is anticipated under § 102, and § 103 is reached only as an alternative. Both titles ("Improvement in valve-gear of steam-engines"; "Improvement in operating-valves for steam-engines") are squarely on point. I could not retrieve either specification and will not characterize their disclosures. This is the highest-value verification gap (see § 7).

5. Secondary considerations and the counter-arguments a defender would make

6. Flagged contradiction within the source data (not a contradiction with the prior sections)

While searching, the identifier "US84615A" returned a Google Patents PDF for US 84,761 (Hugh Reid, "Improvement in Steam-Engine Valve-Gear," 1868-12-08) — a different patent. Similarly, the query string "104,224" returned the 1853 Commissioner's Report entry for No. 10,018 (Townsend) and other five-digit numbers, not US 104,224. Consistent with the earlier sections' express warning about number confusion, I record these as search-engine artifacts and do not treat them as the references named in the "Similar Documents" list. The Hugh Reid US 84,761 disclosure was nonetheless reviewed on its own terms in § 4(B)/(C) context, and it independently confirms that "full-stroke" rock-shafts "worked by cam-rods from the driving-shaft of the engine" were conventional.

7. Conclusion and confidence

Conclusion: On the retrievable pre-1873 record, the single claim of US 134,944 is more likely than not obvious under § 103 — and carries a material § 102 anticipation risk — in each of the following postures:

1. Cam-on-shaft with unequal arms + known adjustable-eccentric technique (Schenck 1855 + Burgh 1870/1872 adjustables), motivated by the field's well-documented objective of reducing cam/rockshaft count. Strongest combination.
2. Known trip/cut-off gear + known eccentric cam on the crank shaft (Sickels 1842 / Corliss 1849–51 / Stewart 1863 + Burgh cam-and-frame gear), motivated by consolidating two known valve-timing functions into one mechanism.
3. Single-reference anticipation by US 104,224 (1870) or US 130,654 (1872) if either shows the offset-cam-on-crank-shaft geometry — unverified.

The reason a § 103 combination is easy here is structural, not merely evidentiary: L3 recites the definition of an eccentric, and the art of the day expressly taught (a) that an eccentric is a narrow cam in a ring, (b) that the eccentric's center revolves about the shaft center "as a crank pin," (c) that a crank pin can do everything an eccentric can do, and (d) that shifting that center relative to the shaft was a routine adjustable-eccentric design variable documented in six commercial variants by 1868. L1, L2, L4, L5 and L6 add only old elements, a result, and a part count.

Confidence:

• High that the 21 post-1873 "Similar Documents" are not § 103 prior art and should be excluded.
• High that Burgh (1870/1872) and Schenck (1855) are § 102(b) art and that their combined teachings reach L2–L5.
• Moderate as to the exact disclosures of US 54,090, US 84,615, US 104,224, and US 130,654 — not retrieved; not characterized.
• Unknown whether the claim was ever actually challenged; § 282 invalidity practice and the 1952 Act both post-date expiry.

Verification gaps (in priority order): (1) full text of US 104,224 and US 130,654; (2) full text of US 54,090 and US 84,615; (3) the filing date of US 134,944 (absent from the record) to settle whether the 1872-08-20 reference is § 102(b) or only § 102(a) art; (4) the 1870 vs. 1872 printing of Burgh, to confirm the printed-publication date of the "centre of the eccentric revolves around the centre of the shaft" passage.

Sources: Google Patents US134944A (https://patents.google.com/patent/[US134944](/patent/US134944)/en) for the specification, claim, and "Similar Documents" list; Annual Report of the Commissioner of Patents (U.S. Patent Office, 1853, 1855, 1856, 1858) via archive.org/Google Books and the Wikimedia-hosted 1855 volume; N. P. Burgh, Link-Motion and Expansion-Gear, Practically Considered (E. & F. N. Spon, 1870/1872) via https://books.google.com.sg/books?id=MaDVAAAAMAAJ and https://forgottenbooks.com/es/download/LinkMotionandExpansionGear_10022275.pdf; US 38,611 (1863) and US 30,138 (1860) via patentimages.storage.googleapis.com; US 84,761 (1868) likewise; Corliss v. Wheeler & Wilson Mfg. Co., Case No. 3,233, 2 Fish. Pat. Cas. 199 (C.C.D. Conn. 1861) via https://law.resource.org/pub/us/case/reporter/F.Cas/0006.f.cas/0006.f.cas.0561.pdf; Smithsonian Institution, Catalogue of the Mechanical Collections (Sickels 1842; Allen 1841/1842/1848; Luttgens 1851) via https://repository.si.edu/bitstream/handle/[10088/10218](https://assignmentcenter.uspto.gov/search/patent/reelFrameDetail?reelFrame=10088-10218)/1/USNMB_1731939_unit.pdf.