US 660675

I'll search for this specific patent number as requested.

Scope and search notes (read first)

Two of the requested steps could not be completed as literally stated, and I want to be explicit about that rather than fill the gap:

• No USPTO PatentCenter / CAFC docket API was available to me. I could only run general web searches. I searched for the number in combination with "patent," "CAFC 2026 docket," "appeal," and the inventor/title. I found no CAFC 2026 docket entry — or any litigation — involving US 660675. That is also the expected result for structural reasons: this patent's Google Patents record shows an anticipated expiration of 1917‑10‑30 (it carried an 1899/1900-era term of 17 years). A patent that expired in 1917 cannot generate a 2026 Federal Circuit appeal. I am stating this as a reasoned conclusion from the record provided, not as a claim to have exhaustively queried every docket.
• The bare number "660675" produces false-positive hits that are not this patent and should not be conflated with it:
  • A Dallas, Texas mailing address / ZIP "+4" code: "PO BOX 660675 #37585, Dallas, TX 75266-0675" (appears in IPR petitions and a TTAB appeal brief for Bulletproof Property Management / Langlotz Patent & Trademark Works).
  • AU 660675 B2 — an Australian patent titled "Method for regulating enzyme activities by noble gases" (unrelated subject matter, different country, different document).
  • A Texas-history digitization hit for a different 1900 patent, "Rotary Reciprocating Engine" by Win D. Williams (issued May 8, 1900) — a different inventor, different title, different document.

The bibliographic and claim content below is taken from the authoritative full text of US 660675A supplied in the patent record (Google Patents, fetched 2026‑09‑24), which controls over the search results per the instructions.

Bibliographic summary — US 660,675 (US660675A)

Abstract

US 660,675 has no formal abstract — abstracts were not a feature of US patents until the 20th century. The patent's own summary statement (rendered on Google Patents as a "Definitions" entry) reads:

"This invention relates to improvements in rotary engines, and possesses the useful and novel features hereinafter described and claimed."

and its stated object:

"The object of my invention is to provide a successful rotary engine that may be operated by any of the well-known powers—such as steam, compressed air, gas, or gasolene—and in which the force is applied directly to the piston-wheel at or near the outer circumference."

Structural synopsis (from the specification): A base A and semicylindrical casing B form a chamber housing a piston-wheel O on shaft D, whose axis is eccentric to the chamber center. The wheel periphery carries a series of cams E, which control an admission valve G normally spring-pressed (spring c) against the cams. Pistons/flanges F are mounted on the wheel adjacent the high points of the cams, are bifurcated (extending on each side of the wheel), and are radially adjustable via set-screws a. An air-tight chamber H is formed in the base, occupying roughly one-third of the wheel circumference, extending from above inlet passage e to exhaust passage d, with adjustable side walls J set by set-screws b. Power enters port f; when valve port i registers with passage e, pressure enters chamber H and acts successively on the flanges F, rotating the wheel. As each cam's rising surface lifts valve G, admission is momentarily cut off while chamber H exhausts through d; as the next cam's lower surface approaches, spring c lets the valve drop and re-register. The specification stresses that valve G "forms a wall closing the end of the air-tight chamber H and receives all the back pressure," and that the cams/wheel contact other parts only while passing through chamber H, so "friction is reduced to a minimum."

Independent claims — plain-language overview

The patent closes with "Having described my invention, I claim." followed by what the record presents as three numbered claims (I read all three as independent combination claims; none depends from another). ⚠️ OCR caveat: the claim text as rendered in the captured record is partially garbled for claims 2 and 3, with words run together and at least one truncated fragment. I flag exactly where below; the paraphrases are reliable in substance, but the literal wording for claims 2–3 cannot be certified from this capture alone.

Claim 1 — the core rotary-engine combination.
A rotary engine combining: (a) a piston-wheel having cams; (b) an inlet valve controlled by those cams; (c) an air-tight chamber within the casing; and (d) pistons or flanges carried by the piston-wheel that receive the pressure as they enter the air-tight chamber. Two additional limitations: the pistons/flanges project over the sides of the piston-wheel (the bifurcated/overhanging geometry), and there are means for adjusting the pistons or flanges (the set-screws a). Wording is clean in the record.

Claim 2 — casing + chamber combination with sealing and adjustment.
Combining a casing and an air-tight chamber formed therein with: a piston-wheel; cams on the wheel; an inlet valve operated by the cams to admit pressure to the air-tight chamber; and pistons/flanges carried by the wheel having extensions projecting on each side of the piston-wheel, where the pistons and wheel are adapted to form air-tight inclosures for the chamber, and the pistons receive pressure from the admission-valve as they enter the chamber; plus means for adjusting the positions of said pis… ⚠️ The record truncates at "said pis" — contextually "said pistons" (or "pistons/flanges"). Substantively this is claim 1 recast with the sealing/air-tight-inclosure and side-extension limitations made explicit and tied to the casing-and-chamber environment.

Claim 3 — the valve-as-end-wall combination.
⚠️ The opening of this claim is garbled in the capture; it begins mid-phrase ("…tight chamber and forming a wall for one end of the air-tight chamber"). Reconstructed from context and the specification's stated key feature, it reads as a combination with a casing and an air-tight chamber, an inlet valve at the air-tight chamber that forms a wall for one end of the air-tight chamber, cams on the piston-wheel controlling the valve's position, and pistons carried on the wheel that receive pressure as they enter the air-chamber, the pistons having bifurcations or extensions projecting on each side of the wheel, plus means for adjusting said pistons. This claim is distinctive because it recites the inventor's self-described "important feature" — valve G forming an inclosing wall for the end of chamber H to take the back pressure.

Common thread across all three: eccentric piston-wheel + cam-actuated inlet valve + sealed working chamber + radially adjustable, side-overhanging pistons/flanges. The adjustability limitations (set-screws a for pistons; set-screws b for chamber side walls J) and the valve-as-wall feature are the notable points of novelty the inventor emphasized.

Uncertainty / limitations of this summary

• Claims 2 and 3 as literally worded are not fully certifiable from the captured text; the OCR/photocopy is degraded at exactly the points noted. My claim 2 and claim 3 paraphrases are contextual reconstructions. If you need verbatim claim language, pull the original patent PDF from the USPTO or Google Patents document images rather than the OCR text.
• I could not verify the bibliographic fields against PatentCenter directly, and no CAFC 2026 docket exists for this number on the evidence found (and none is expected given the 1917 expiration).
• If your underlying intent was a different 660675 — e.g., AU 660675 B2 (noble-gas enzyme regulation, the only other patent document with that number that surfaced) — that is a separate, unrelated document, and I did not summarize it here. Say the word and I'll pull it up.

I'll search for litigation involving US patent 660675 across patent litigation databases.

Let me search the litigation-specific portals and verify against the patent's specific number.

Let me do a few final targeted checks against litigation databases and any historical case law.

Litigation Search Results — US Patent 660,675

Conclusion: No litigation is known involving US Patent 6,606,75 / 660,675.

I searched patent‑litigation resources (including Unified Patents' litigation portal, PACER/CAFC‑oriented sources, CourtListener, and general web indexes) for the specific number 660675. I found no record of any lawsuit, PTAB/ITC proceeding, or CAFC appeal in which US Patent 660,675 was asserted or challenged.

Why this result is expected

The authoritative patent record (Google Patents, US660675A) shows this is a very old patent that cannot support modern litigation:

Because the patent expired in 1917, any cause of action for infringement of its claims would have been time‑barred more than a century ago. There is no mailbox‑eligible, enforceable term remaining, and no post‑issuance proceedings (IPR/PGR/CBM) are legally possible for a pre‑AIA 1900 patent.

Important caveat on false positives

My searches surfaced many hits containing the string "675" or "660675," but none refer to US Patent 660,675. Do not treat these as litigation involving this patent:

• Canady v. Erbe Elektromedizin (D.D.C.; e.g., 1998 summary‑judgment opinions, appeal at CourtListener/Harvard PDF 2290761) — concerns Canady's '675 patent (a different, modern patent, on endoscopic handles/probes), not US 660,675.
• Applera v. MJ Research opinions from the District of Connecticut (ctd.uscourts.gov PDFs; e.g., 021204.JBA_.AppleraMJ.pdf, 030404.JBA_.MJApplera.pdf) — concern the '675 patent in PCR thermal‑cycler litigation, again a different patent.
• Bulletproof Property Management, LLC v. Tesla, Inc., Case No. 1:25‑cv‑00665 (W.D. Tex.), and related IPR papers — involve unrelated patents; the "660675" appearing there is a post‑office‑box zip+4 (P.O. Box 660675 #37585, Dallas, TX 75266), not a patent number.
• AU 660675 B2 ("Method for regulating enzyme activities by noble gases") — an Australian patent with a coincidentally similar number, unrelated to US 660,675.
• Various non‑patent uses of "660675" (a CE certificate number, a Chinese securities code, a customs lot number, a credit‑report file) — all irrelevant.

If you need certainty beyond my search

I cannot rule out a hypothetical 1900–1917‑era infringement or interference action that never made it into modern digitized databases; such antique records are generally not indexed in current litigation portals. If you want to pursue that unlikely possibility, the appropriate checks would be:

• Historical USPTO records / National Archives for late‑19th/early‑20th‑century interference proceedings involving App. No. 491,700.
• Federal court records predating 1917 in the Southern District of Ohio (Dayton) — not accessible through PACER, which is not retroactive to that era.
• The USPTO Patent Assignment / Global Dossier records (already reflected above as "Individual" assignee, no assignment history).

Bottom line: Based on all available and searchable sources, there is no known litigation — district court, ITC, PTAB, or CAFC — involving US Patent 660,675.

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

Proceedings overview

Total AIA trial proceedings on US 660675: 0. Not active — 0; claims invalidated — 0; claims sustained — 0; settled — 0; institution denied — 0. The USPTO Open Data Portal structured block returns no AIA trial proceedings, and targeted web searching surfaced no IPR, PGR, CBM, derivation, or reexamination record for this patent. The bottom line for a defendant is not "the patent is hardened" or "the claims are canceled" — it is that no AIA proceeding exists or can meaningfully exist, because US 660675 issued on 1900-10-30 and expired 1917-10-30 (Google Patents US660675). Any demand letter citing this patent as a live right is legally incoherent, and the "Expired – Lifetime" status in the structured data is an INPADOC-style retrospective label, not a signal of current enforceability.

Why there are no proceedings to itemize

The requested per-proceeding format has no entries. Rather than fabricate docket numbers, here is the affirmative basis for the null result, plus the two adjacent records that a careless search will misattribute to this patent.

Eligibility analysis (why the docket is necessarily empty)

• Filing / grant / expiry. Application US491700A filed 1900-02-12; Patent No. 660,675 granted 1900-10-30; anticipated expiration 1917-10-30 (17-years-from-grant term under the law then in force; pre-1980 there were no maintenance fees to lapse). The patent has been in the public domain for 109 years.
• Post-Grant Review is categorically unavailable. PGR (35 U.S.C. §§ 321–329) reaches only patents with an effective filing date on or after 2013-03-16. A 1900 effective filing date is ~113 years too early.
• CBM review is categorically unavailable. Covered Business Method review (AIA § 18) sunset on 2020-09-16 and, in any event, was limited to financial-services business-method claims — inapplicable to a mechanical rotary engine under F01C.
• IPR is technically available in the abstract but practically dead. IPR (35 U.S.C. §§ 311–319) has no patent-eligibility cutoff and the Board has instituted IPRs on expired patents. But an IPR on a patent that expired in 1917 would confer no possible benefit: there is no live infringement exposure to defeat, no damages period to shorten (35 U.S.C. § 286 caps recovery at six years pre-suit, and the patent lapsed a century before), and no § 315(e) estoppel benefit for the petitioner's real litigation against real, unexpired patents. No rational petitioner files one.
• No PTAB, CAFC, or district-court activity located. No Federal Circuit or CourtListener entry, no PTAB E2E record, no reissue or reexamination certificate appear for this patent. Caveat, stated honestly: pre-2012 and pre-digitization records for 1900-era patents are incomplete, so this is a high-confidence negative, not a certified clean bill.

Do NOT conflate these — common false positives from searching "660675"

Strategic summary

Claim status: all claims UNTESTED — and untestable. Claims 1, 2, and 3 of US 660675 (as printed: claim 1 – piston-wheel with cams, cam-controlled inlet valve, air-tight chamber, projecting/adjustable flanges; claim 2 – the same combination with the valve forming an inclosing wall and adjustable side walls J; claim 3 – valve forming a wall at one end of the air-tight chamber with bifurcated pistons) were never canceled, confirmed, or construed by the PTAB — no proceeding exists. That is not "sustained"; it is moot. There is no live claim scope to infringe, so there is no "surviving claims" list to give you.

Estoppel landscape: none, in either direction. Because no IPR/PGR was ever filed, § 315(e)(2) estoppel never attached to anyone, and there is no petitioner-privity web to trace. Symmetrically, prosecution-history or IPR-based estoppel arguments against the claims are unavailable — there is no IPR record to mine. If someone asserts 660675 against you, your affirmative defense is not an IPR ground; it is expiry plus § 286 (no infringement is even theoretically possible, and no damages can accrue on a right that lapsed 1917-10-30), and, if needed, patent misuse / Rule 11 exposure against the asserting party for citing a 1917-expired patent in a demand letter.

Pattern signals: none. No repeat petitioner, no PTAB appeal history, no defensive aggregator (Unified Patents, RPX, or similar) in the chain — Unified's IPR focus is post-2012 patents in active NPE campaigns, and this patent predates the AIA by 112 years. The patent's real modern footprint is as prior art: the F01C21/08 / F01C21/0818 / F01C21/0836 classifications (rotary pistons; vane construction; vane tracking by cams/rollers) put it squarely in the thicket that modern rotary-engine filings — Wankel-adjacent designs, vane-type expanders/compressors, and rotary/compressor claims generally — must distinguish over. Its disclosed cam-actuated inlet valve, its air-tight chamber spanning roughly one third of the cam-wheel circumference, and its adjustable bifurcated flanges are concrete § 102 anticipatory material for anything claiming that architecture.

Recommended next steps

If you are a defendant facing an assertion of US 660675:

1. Do not build an IPR strategy — there is nothing to file on and no benefit to filing. The governing document is the printed patent itself, which states on its face: filed 1900-02-12, granted 1900-10-30, and (per Google Patents) anticipated expiration 1917-10-30 with status "Expired – Lifetime."
2. Respond with a § 286 / expiry-based non-infringement position: no act after 1917-10-30 can infringe, and § 286 bars recovery for any act more than six years before suit. Preserve Rule 11 / § 285 arguments against the asserting party.
3. Demand the asserting party state, in writing, the claim numbers, the issuance date, and the expiration date it contends is in force. A demand letter that cannot survive that question is itself the evidence.
4. If the assertion is instead an invalidity citation against a modern patent you own, treat 660675 as usable § 102 art (a 1900 printed publication) and verify whether your target's claims recite cam-actuated inlet valving, circumferential air-tight chamber segments, or adjustable projecting vanes — those are this reference's core disclosures.

If your interest is defensive prior-art landscaping rather than this specific assertion: pull the full F01C21/08 sub-class and look at 660675's neighbors (US 665,970; US 663,972; US 609,049; US 631,169; US 716,503; US RE12,631) — that cluster of 1898–1907 US rotary-engine patents is a compact, high-yield § 102 archive for rotary-piston and vane-tracking claims.

On the null result itself: the absence of PTAB activity here is not the usual weak signal (well-asserted patents eventually attract IPRs). It is a structural certainty — a patent that expired in 1917 cannot attract an AIA trial. Do not read the empty docket as "the claims are strong." Read it as "the claims are gone."

Assignment / Ownership Analysis — US Patent 660,675

Primary-source caveat up front: The USPTO Patent Assignment Center / Patent Assignment Search covers assignment records for patents granted from roughly August 1980 forward (the online database's coverage window; older records exist only on microfilm/paper at the USPTO and in the National Archives, and are indexed neither in Assignment Center nor in Google Patents' legal-events table). US 660,675 issued 1900‑10‑30 and expired 1917‑10‑30, so it falls entirely outside the electronic assignment record. This is a coverage limitation, not evidence that an assignment never occurred. All statements below are therefore bounded by that limitation, and I flag explicitly where I am not able to determine a fact.

Inventors

Notes:

• The specification is a single-inventor instrument ("I, CHARLES I. WILLIAMS, a citizen of the United States, residing at Dayton…"), so the "all inventors leave within 12 months" fire-sale precursor pattern cannot apply — there is only one inventor.
• The patent's face shows no corporate assignee and no "assignor to" notation, which under 1900 practice strongly indicates Williams filed without an assignment obligation to an employer (i.e., an independent inventor, not a company engineer under a pre-filing assignment covenant). I state this as an inference from the instrument's face only, not as a documented finding.
• My searches for Williams' employment, his assignee(s), or any Dayton-based engine manufacturer connected to him returned nothing usable. I could not determine whether he worked for a Dayton manufacturer at the time of filing. I will not guess.
• The specification carries the notation "(No model.)", i.e., no physical model was filed with the application under the then-applicable practice. There is no co-inventor, no joint-ownership split, and no evidence of a second Williams engine patent in the same family in the record supplied.

Original assignee

• Named on the issued patent: none other than the inventor himself. Google Patents renders both Original Assignee = "Individual" and Current Assignee = "Individual" (i.e., no assignee of record distinct from the inventor).
• Primary line of business: Not applicable — the patent was held by an individual, not an entity.
• Shipped a product embodying the claims? Not established. The patent is drafted as a workshop/inventor engine ("a successful rotary engine… operated by steam, compressed air, gas, or gasolene"), with hand-fitted features such as set-screw-adjustable pistons F and set-screw-adjustable chamber side walls J (claim 2's "means for adjusting the positions of said pistons"; col. describing set-screws a and set-screws b). Adjustable-by-set-screw construction is characteristic of an experimental or small-batch machine, but that is an inference from claim drafting, not commercial evidence, and I found no catalogue, trade-press item, or company record showing manufacture or sale.
• Current status: The patent expired by its own term on 1917‑10‑30 (Expired – Lifetime per the legal-status listing). It is long since in the public domain. Any entity that might have succeeded to ownership has, for practical purposes, no enforceable right remaining.

Assignment timeline

There are no recorded assignments for US 660,675 in the sources available to me.

• USPTO Assignment Center / Patent Assignment Search — no retrievable record. The database's coverage begins around August 1980; a patent that issued in 1900 and expired in 1917 predates the electronic record by eight decades.
• Google Patents legal events for US660675A list only the prosecution chain, with no assignment, security-interest, merger, change-of-name, license, or release events:

• Reel/frame: none available to cite. I am deliberately not inventing a reel/frame number; no such record was surfaced.
• Correspondent of record: none available. The only attorneys/agents named anywhere on the instrument are the witnesses to the inventor's signature — "JOHN W. KALBFUS" and "R. J. McCARTY" — which in 1900 practice are simply subscribing witnesses, not prosecuting attorneys and not assignment-recordation correspondents. I flag this so neither name is later mistaken for a repeat-player filing attorney.

Reading: There is no chain to diagram beyond the patent's own dates. Per the framing above, the absence of post-issuance records most plausibly means the patent remained with the inventor (or his personal heirs/devisees) and was never the subject of a recorded transfer before it lapsed — but because electronic records do not reach back to the relevant period, this is the default inference, not a verified fact.

Timeline diagram

Only patent-life events are supportable; I have not added any assignment nodes because none are documented.

timeline
    title Ownership of US 660675
    1900 : Application filed by Charles I Williams
         : Issued to Williams as individual
    1917 : Patent term expires
         : No recorded assignments found

NPE / troll-pattern signals

Every signal is assessed against the constraint that no electronic assignment records exist for this patent. "Not present" below means "no evidence of the signal in any available source," and I note where the honest answer is "cannot be assessed."

1. Shell-entity transfer — Not present. No assignee entity of any kind appears in the record; the patent's original and current assignee fields both read "Individual." No "IP / Holdings / Ventures" successor, no registered-agent address, no single-member LLC. (Cannot be conclusively excluded for the 1900–1917 window given the record gap, but there is no affirmative evidence whatsoever.)

2. Known asserter in the chain — Not present. No Acacia, Marathon, IV, IPNav, Wi‑LAN, Mosaid/Conversant, Vringo, Pendrell, Round Rock, MPHJ, Lumen View, or Spangenberg entity appears anywhere in this patent's history. Assignee of record is an individual. No Unified Patents or RPX high-frequency-plaintiff match.

3. Repeat correspondent across the chain — Not present / Not applicable. There is no chain, therefore no recurrence. The only names on the instrument (Kalbfus, McCarty) are signature witnesses, not recordation correspondents, and each appears exactly once. I did not find either name on any NPE assertion list.

4. Cascading transfers — Not present. Zero recorded transfers, so no <24-month LLC relay, no shared correspondent address, no common principals.

5. Pre-litigation transfer — Not present / moot. There is no infringement suit. Consistent with the previously generated litigation section, US 660,675 has no known litigation in district court, the ITC, PTAB, or the CAFC. With no suit, there is no six-month transfer window to test.

6. Bankruptcy fire-sale — Not present. No assignee entity exists to file Chapter 7/11; no Kodak/Nortel/Polaroid-style sale record exists for this patent. The inventor's own estate status is not documented in any source I could reach.

7. Privateering — Not present. No operating company, no NPE transferee, no SEC 10‑K/8‑K disclosure, and no Patent Progress / EFF coverage connecting this patent to a proxy-assertion arrangement.

8. Defensive aggregator (anti-NPE) — Not present. The patent was never acquired by RPX, AST, LOT Network, Unified Patents, or OIN. It lapsed naturally in 1917 rather than being neutralized by purchase.

Cross-reference consistency: This section is fully consistent with the earlier litigation summary (no suits, expired 1917). No contradiction to flag.

Verdict

Insufficient data — no assignment records exist for this patent.

There is exactly one supportable ownership fact: US 660,675 issued 1900‑10‑30 to Charles I. Williams of Dayton, Ohio as an individual, with no corporate assignee on the instrument, and it expired 1917‑10‑30 (Google Patents legal events; USPTO "Expired – Lifetime" status). Because the USPTO Assignment Center's electronic coverage begins around August 1980 and Google Patents shows no assignment events of any kind, there are no reel/frame entries to analyze and therefore no basis to find a single NPE signal, weak or strong — all eight are either not present or unassessable, and the "no records / only the original inventor-held patent" case maps squarely onto the Insufficient data option, not onto any NPE category.

Verify at: https://assignment.uspto.gov/patent/index.html (search "660675" — expect no post‑1980 records) and https://patents.google.com/patent/[US660675](/patent/US660675)/en (legal events table reproduced above).

I'll search for the specific patent number 660675 and its cited prior art references.

Let me search more specifically for citation data on this patent and verify the USPTO record.

Let me run additional targeted searches to determine whether any citation data exists for this patent.

Summary Answer

I could not identify any patent citation for US 660,675 — because, on the authoritative record, this patent has none. Verified against the full text and bibliographic record of US660675A on Google Patents (https://patents.google.com/patent/[US660675](/patent/US660675)/en), there is:

• No "References Cited" / "Patent Citations" section (no examiner-cited or applicant-cited prior art).
• No "Cited By" / forward-citation section (no later patent in the digitized corpus cites US 660,675).
• No citation of any prior patent or publication anywhere in the specification. The description refers only to the accompanying drawings and to no earlier patent, publication, or known device.

The only reference-type list appearing on the record is a Google-generated "Similar Documents" list. I address that below, and I flag it explicitly: it is not a citation list and must not be treated as such.

My web searches for citation data on this specific number ("660675", "US 660,675", Williams rotary engine 1900 cited references, USPTO PatentCenter/App. 491,700) returned no citation record and no relevant hit; the only "rotary engine" documents surfaced were unrelated patents of other numbers (e.g. the WO 2005/047655 search report, US 4,148,292, EP 0103985) whose "675"/"660675" appearances are coincidental. I was also cut off by a search-step limit before completing further queries, so I state that as a limitation.

Verified Bibliographic Record for the Requested Number

This is consistent with the litigation section already produced; nothing here contradicts it.

Why No Citations Exist — and Why That Is the Correct Answer

1. Pre-1947 USPTO printing practice. The practice of printing a "References Cited" list on the face of a granted U.S. patent began only in the mid-20th century (with the modern first-page format). Papers in the file wrapper of an 1900 application were not printed on the granted patent. For patents of this era, citation metadata is therefore absent by design, not merely unindexed.
2. The specification itself cites nothing. The full text of US 660,675 contains no reference to any earlier patent or printed publication — only to "the accompanying drawings" and the lettered parts.
3. Digitization limits. Google Patents and USPTO full-text for the 1842–1905 "similar document" cohort carry no citation links into or out of US 660,675. Absence of "Cited By" for a 1900 patent is normal, since forward citations are only captured where they exist.
4. The examiner's references, if any, survive only in the original file wrapper (App. No. 491,700), which is not in the online citation databases. See the retrieval path below.

I will not invent citations. Supplying specific prior-art references and §102 anticipation mappings for US 660,675 would require fabricating both the references and their disclosures, because the record contains none.

"Similar Documents" List — NOT Citations (Flagged Explicitly)

Google Patents renders a machine-generated "Similar Documents" list for US 660,675. It reflects textual/classification similarity, not a citation relationship, and none of it is examiner- or applicant-supplied art. It cannot support a §102 statement. I reproduce it for completeness with that caveat.

Item I — Pre-dating the 1900-02-12 filing (the only items that could even theoretically be §102(a)-type art):

Item II — Post-dating the filing (incapable of §102(a) anticipation of this filing; listed only for completeness): US 663,972 A (1900-12-18, Steam-engine); US 665,970 A (1901-01-15, Rotary engine); US 710,769 A (1902-10-07, Motor); US 716,503 A (1902-12-23, Rotary engine); US 727,861 A (1903-05-12, Rotary engine); US 790,969 A (1905-05-30, Reversing-valve for engines); US 793,664 A (1905-07-04, Rotary engine); US RE 12,631 E (1907-04-09, Rotary engine).

Important: I have only the truncated titles and dates from the similarity list. I have not verified the disclosure of any of these documents. Accordingly I cannot and do not assert that any of them anticipates any claim of US 660,675. Any such mapping would be unsupported. Note also that US 663,972 A (granted 1900-12-18) is a borderline case: its grant post-dates the Feb. 12, 1900 filing, but I do not have its filing date, so it cannot be classified without the underlying record.

For reference, the claims that any candidate art would have to meet are:

• Claim 1 — piston-wheel with cams; inlet-valve controlled by the cams; air-tight chamber within the casing; pistons/flanges on the piston-wheel projecting over the sides of the wheel and receiving pressure on entering the chamber; means for adjusting the pistons/flanges.
• Claim 2 — casing + air-tight chamber; piston-wheel; cams; inlet-valve operated by the cams; bifurcated pistons/flanges projecting on each side of the wheel; pistons and wheel forming air-tight inclosures; adjusting means.
• Claim 3 — casing; a valve forming a wall for one end of the air-tight chamber; cams on the piston-wheel controlling that valve's position; pistons with bifurcations/extensions on each side of the wheel; adjusting means.

Statutory Caveat on "35 U.S.C. § 102" for This Patent

Because US 660,675 was filed 1900-02-12 (and expired 1917-10-30), the modern framework is anachronistic:

• AIA § 102 (post-March 16, 2013) does not govern this application at all.
• A 1900 filing was examined under the pre-1952 statutes (Revised Statutes, as amended by the Acts of 1870/1897), i.e. novelty/anticipation against the state of the art before the invention, plus the statutory public-use/on-sale bars in force at the time.
• Even the pre-AIA 35 U.S.C. § 102(a)/(b) framework (1952–2013) did not exist in 1900. Applying it is at best a post-hoc analogy.
• A reference can only be anticipatory here if it pre-dates the applicant's invention or the 1900-02-12 filing (subject to the statutory bars of the era). Everything dated after Feb. 12, 1900 (Item II above) is therefore excluded from a §102(a)-type analysis on its face, absent an earlier effective filing date.

What Would Actually Be Required to Establish the Prior Art for US 660,675

Since the granted patent prints no references, the only reliable sources are archival:

1. The original file wrapper for App. No. 491,700 (Series of 1900) — the examiner's references, if any, would appear in the Office actions. Obtainable via USPTO PatentCenter/Assignment records or the National Archives (Record Group 241, Patent Office records).
2. The Official Gazette of the U.S. Patent Office, vol. for Oct. 30, 1900, for the notice of allowance/claim printing.
3. Historical US classification schedules (Class 123/418-era equivalents) and the antique rotary-engine art published before 1900 — a genuine §102-style search, not a citation lookup.
4. Interference/priority records, 1900–1917, if any (not in digitized litigation databases), per the litigation section.

Bottom Line

• US Patent 660,675 by Charles I. Williams (filed 1900-02-12, granted 1900-10-30) has no recorded prior-art citations — none printed on the patent, none cited in the specification, and none available in the online citation databases.
• Therefore no §102 anticipation mapping can be provided from the citation record, because that record is empty. Any specific reference I named as anticipating a claim would be fabricated, and I am not doing so.
• The "Similar Documents" list is not a citation list; its 17 pre-1900 entries are merely search candidates for a genuine historical novelty search, and their disclosures remain unverified.
• Establishing the actual prior art for this patent requires the original file wrapper for App. No. 491,700 and a physical/archival search of pre-1900 rotary-engine art — not a citation lookup.
• Search limitation: I exhausted my allotted search steps before completing additional targeted queries; the conclusions above rest on the authoritative Google Patents full text already provided plus the searches completed.

I'll ground this analysis in the actual prior-art references listed on the patent page, verifying dates and content where I can.

Excellent — US4776A (Miller, 1846) and US621721A (Spence, 1899) returned substantive text. Let me pull the remaining similar-document references.

Obviousness Analysis — US Patent 660,675 ("Rotary engine," Charles I. Williams, filed 1900‑02‑12, granted 1900‑10‑30)

0. Two threshold caveats before the § 103 analysis

Caveat A — § 103 does not legally apply to this patent. US 660,675 was filed February 12, 1900. 35 U.S.C. § 103 was enacted by the Act of July 19, 1952 and applies only to applications filed on or after January 1, 1953. A 1900 filing is governed by the Patent Act of 1870/1897 as amended (Rev. Stat. §§ 4886, 4892, 4920), under which the dispositive question was want of invention — the Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248 (1851) standard ("more ingenuity and skill … than were possessed by an ordinary mechanic acquainted with the business"). I am performing the requested § 103 analysis by analogy to that "invention" requirement. The substantive reasoning largely carries over; the statutory labels do not.

Caveat B — the "Similar Documents" list is not an examiner's prior‑art citation list. Google Patents' "Similar Documents" table is machine‑generated similarity output. The fetched record for US660675A contains no "References Cited" section and no examiner citations, so none of these documents were relied on by the Patent Office (there was no such reliance of record). Every entry therefore has to be independently date‑screened against the 1900‑02‑12 filing date — or, more precisely under the 1870 Act, against Williams' date of invention (first‑to‑invent), which is his burden to prove.

1. The claims as literally presented

The OCR of the claim section is damaged. Claim 1 and most of claim 2 are legible; claim 2's tail runs into claim 3, and claim 3's opening words are missing. I will not repair the text. As it reads:

• Claim 1: piston‑wheel having cams; inlet‑valve controlled by said cams; air‑tight chamber within the casing; pistons or flanges carried by the piston‑wheel receiving pressure as they enter the chamber; said pistons or flanges projecting over the sides of the piston‑wheels; means for adjusting the pistons/flanges.
• Claim 2: as claim 1, plus the pistons "having extensions which project on each side of the piston‑wheel," the pistons and wheel "adapted to form air‑tight inclosures for said chamber," and means for adjusting the pistons' positions.
• Claim 3 (partially reconstructed from OCR): a valve "…tight chamber and forming a wall for one end of the air‑tight chamber"; cams on the piston‑wheel controlling the position of said valve; pistons receiving pressure as they enter the chamber; pistons having bifurcations or extensions projecting on each side of the wheel; means for adjusting said pistons.
• Specification admission material to obviousness: "The pistons F may also be made non‑adjustable." The applicant expressly treats the claimed adjustment means as optional. Also: "the number of [cams] may be varied according to the size of the wheel" — pure design choice.

Note the claim drafting is highly functional ("adapted to form air‑tight inclosures," "projecting over the sides," "means for adjusting") and alternative‑form ("pistons or flanges"). Functionally‑drafted, result‑oriented claim language is the most § 103‑exposed kind.

2. The prior‑art universe, date‑screened

From the page's prior‑art/similar‑documents section (dates as listed, not independently re‑verified except where noted):

Group I — unambiguously predates the 1900‑02‑12 filing (available on the face of the list):

Group II — post‑dates the filing on the face of the list; usable only if the reference's own filing date antedates Williams' invention date, and only with caution under pre‑1952 law: US663972A (1900‑12‑18), US665970A (1901‑01‑15), US710769A (1902‑10‑07), US716503A (1902‑12‑23), US727861A (1903‑05‑12), US793664A (1905‑07‑04), US790969A (1905‑05‑30), USRE12631E (1907‑04‑09 — a reissue, so the original patent's date would control and would need checking).

Under Rev. Stat. § 4886 the bar was "patented or described in any printed publication … before his invention thereof." A US patent not yet granted was not "patented," so Group II is very likely unavailable — this is a material difference from modern § 102(e). Only US663972A and US665970A are close enough in time to be worth a filing‑date check.

3. The two references whose text I could actually retrieve

US4776A — James Miller, Philadelphia, "Rotary Engine," patented Sept 26, 1846. Substantive text obtained. Miller discloses:

• a "cylindric revolver R … having at its axis a hollow shaft … and at its circumference at equal distances, three cams attached, O, O, O, serving as pistons for the steam to act against" → a rotary piston member whose cams function as the pressure‑receiving pistons;
• "In the convex slope, near the vertex of each cam, is an aperture or passage n, connecting with the hollow of the shaft, designed for the escape of air … and for the escape of steam as soon as the aperture in its movement passes the valve" → rotary‑timed exhaust;
• "The use of a valve or gate in the cylindric space between the cams is necessary to receive the backward force of the steam. To secure this object fully, and avoid at the same time an excessive pressure of the valve…" → the valve closes one end of the working space and absorbs the back pressure; and
• "The forward slope which operating lifts the valve" → the valve is actuated/positioned by the cams.

Miller is essentially a 54‑year‑old anticipation of the conceptual core of Williams' claim 3 — including the very feature Williams calls, in his specification, "an important feature of my invention."

US621721A — John Spence, Erie, Pa., filed Dec 9, 1898, granted Mar 21, 1899. Substantive text obtained. Spence discloses:

• "a rotary eccentric piston type" with "the shaft B, carrying the rotary disk C" in casing A — eccentric rotor, as in Williams;
• "the Wings D which are spring‑actuated, the springs E being provided to force the wings outward to receive the impact of the steam" → pistons/flanges receiving the pressure;
• "Each end of the wings is grooved, as at F, to receive a packing‑strip G, and each packing‑strip has pins G' … and a spring H is provided to throw the strip out from the wing toward the cylinder‑head K" → laterally‑extending sealing elements on the pistons, pressed against the side walls;
• "Seated in the faces of the disk are the semicircular rings M, and a spring or springs M are provided … These sectional rings are designed to be thrown out against the cylinder‑heads to form a steam‑tight contact" → the wheel itself is laterally sealed to the chamber side walls (Spence's analogue of Williams' "air‑tight inclosures");
• "the portion of the chamber surrounding the rotary disk is enlarged, as at A', in which enlarged portion the wings are disposed when receiving the impact of the steam, and at one end of this space is an exhaust‑port R, while at its opposite end is a duct S, having branching ducts S¹ and S²" → a working chamber occupying a portion of the circumference, bounded at one end by an inlet duct and at the other by an exhaust port — structurally the analogue of Williams' chamber H "extend[ing] from a suitable point above or beyond the inlet‑passage e to the exhaust‑passage d";
• "the rocking shoe or cut‑off valve J … The valve is rocked by means of eccentric connection with the main shaft" → admission valve whose timing is derived mechanically from rotation of the main shaft.

Additional item surfaced in searching, outside the list (flagged): Scientific American, v.81, no.10, Sept 2, 1899, p.148, "An Improvement in Rotary Engines" (Hay & Depuy, Garland, Tex.) — a rotary engine with a fixed abutment and a sliding valve with registering ports, a rotary cut‑off valve secured to the main shaft, and cylinder‑head grooves that fill with condensate to form a water seal against leakage. Published ~5 months before the filing date; a § 102(a)-style printed publication.

4. Element chart — claim 1 vs. Miller in view of Spence

Claim 2 adds only the "extensions which project on each side" and "adapted to form air‑tight inclosures" — Spence's strips G and rings M are the sealing‑against‑side‑walls teaching. Claim 3's "valve … forming a wall for one end of the air‑tight chamber" is squarely Miller's "valve or gate … necessary to receive the backward force of the steam," read with Miller's cam‑lifted valve.

The only element I cannot map from these two references is the set‑screw piston adjustment (spec: "set‑screws a"). Two responses: (i) the applicant's own specification states the pistons "may also be made non‑adjustable," so the feature is conceded to be optional and carries no patentable weight; and (ii) radial vane/wing adjusters were a commonplace in this class — e.g., the search surfaced a rotary engine (identified as US625446, "a piston‑wheel … loose pistons or wings mounted radially in the piston‑wheel … plugs mounted in the outer cams and rollers carried by the plugs; said plugs being provided with means for turning them and holding them to their adjustment") whose number and date I have not verified and which is not in this page's list. Treat that citation as unconfirmed.

5. Combinations that would render the claims obvious, and the motivation to combine

Combination 1 (claims 1 and 3): US4776A + US621721A. Motivation: both are rotary piston engines in the same class (CPC F01C), addressing the same two recognized problems Miller articulates — sealing the working space and preventing "excessive pressure of the valve" — and Spence articulates — leakage past the wings at the cylinder heads. Miller supplies the cam‑wheel/cam‑driven valve/valve‑as‑chamber‑wall teaching; Spence supplies the eccentric rotor in a part‑circumferential chamber between an inlet duct and an exhaust port, pressure‑receiving vanes, and lateral seals against the side walls. A person of ordinary skill in 1900, seeking a low‑friction rotary engine, would apply Spence's eccentric chamber arrangement and side‑sealing vanes to Miller's cam‑actuated valve wheel as a matter of ordinary mechanical adaptation — the components are functionally independent and their interaction is predictable. Result: a rotary engine with the claimed elements and the claimed result (low friction because the parts touch only while traversing the sealed chamber — Williams' own stated advantage).

Combination 2 (claim 3, strongest): US4776A alone, alone is nearly dispositive. Miller already discloses cams‑as‑pistons, cam‑timed valve actuation, and a valve forming the end wall of the working space and absorbing back pressure. Claim 3's remaining additions — bifurcated side extensions and set‑screw adjustment — are not shown by Miller, but the first is a known sealing expedient (Spence's strips G, ring M; the head‑groove water seal reported in the Sept 1899 Scientific American item) and the second is disclaimed as optional by the applicant.

Combination 3 (claims 1–3): US549484A (1895‑11‑12 "Rotary engine") or US609049A (1898‑08‑16 "Rotary engine") or US341395A (1886‑05‑04 "Rotary engine") or US631169A (1899‑08‑15 "Rotary steam‑engine") as primary, + US621721A + US312126A. These four are the closest-in-time rotary engines in the list, and US312126A ("Steam oscillating valve," 1885‑02‑10) is a dedicated valve reference that speaks directly to the "inlet‑valve" sub‑combination — supporting the view that the valve element was an independently developed, well‑known art area that could be substituted into a rotary engine as a design option. I could not retrieve the text of US549484A, US609049A, US341395A, US312126A, or US631169A, so I state this as a combination hypothesis to be charted, not a conclusion.

KSR-type rationale, stated explicitly:

1. Same field of endeavor / same problem — all references are rotary engines or rotary‑engine valves; the field was so crowded that rotary engines appear in the list from 1842 (US2764A) and 1843/1846 onward.
2. Known substitutability of the timing element — the art already knew at least three ways to time admission to a rotary engine's working space: cam‑lifted valve (Miller, 1846), eccentric‑driven rocking valve (Spence, 1899), and rotary cut‑off valve secured to the main shaft (Hay & Depuy, Sept 1899). Substituting one known rotary‑engine valve actuator for another is precisely the "combination of familiar elements according to known methods" that yields a predictable result.
3. Design choice, not invention — the number and spacing of cams is expressly stated in Williams' specification to be variable "according to the size of the wheel."
4. Result‑oriented limitation — "adapted to form air‑tight inclosures" and "projecting over the sides" state a desired result; Spence teaches the structures that achieve it. Where the claim recites the result and the art recites the way of achieving it, the claim is obvious.
5. Classification evidence of routine combination — the patent itself is classified in F01C21/08 and, in particular, F01C21/0836 — "Vane tracking; control therefor by mechanical means comprising guiding means, e.g. cams, rollers." That a separate CPC subdivision exists for cam‑guided vanes confirms this combination was a recognized, recurring design pattern in the art, not an unlikely leap.

6. Counterarguments the applicant could press (and why they are weak on this record)

• Graham factor 4 — long‑felt need / failure of others. The list shows rotary‑engine patents spanning 1842–1899 with no evidence of commercial success; the inventor's own stated object is "to provide a successful rotary engine," implying the art had failed. That could be argued as nonobviousness evidence. But (i) there is no evidence in this record of a nexus between any secondary consideration and the claimed structure; (ii) Williams' engine itself apparently achieved no commercial success (by 1917 the patent simply expired); and (iii) the inventor's own disclaimer of piston adjustability removes the only arguably novel structural element from the claim's criticality.
• The claim's "air‑tight chamber." Williams stresses it as producing minimum friction. But the chamber is defined functionally as the region where the valve, wheel, and flanges cooperate — a result, not a structure.

7. What must be retrieved before relying on this analysis

I want to be explicit about the limits of what I verified:

1. Unretrieved: US549484A, US609049A, US341395A, US312126A, US631169A, US612969A, US602059A, US398143A, US416147A, US476868A, US206380A, US40278A, US2764A, US44901A. I have only their listed dates and titles, not their disclosures. Full‑text retrieval is required before any of them can be charted as anticipating or suggesting.
2. Unverified dates: all Group I dates come from the Google Patents similarity table; I verified US4776A (1846‑09‑26) and US621721A (filed 1898‑12‑09 / granted 1899‑03‑21) against their own specification text. The rest should be confirmed against the printed patents.
3. Group II: check filing dates for US663972A and US665970A. Also check whether USRE12631E's original patent predates 1900‑02‑12. Under the 1870 Act, the remaining Group II items are almost certainly unavailable.
4. US625446: number and date unverified and not in this page's list — do not rely on it without confirmation.
5. Claim text: claim 3's opening is missing from the OCR; my element breakdown of claim 3 is a reconstruction and should be confirmed against the printed patent.

8. Bottom line

On the material I can actually read, claims 1, 2, and 3 of US 660,675 are prima facie obvious over US4776A (Miller, 1846) in view of US621721A (Spence, 1899) — the two references supply every claimed element except the set‑screw piston adjuster, which the applicant's own specification concedes is optional ("The pistons F may also be made non‑adjustable"). Claim 3 is the weakest, because it centers on the valve "forming a wall for one end of the air‑tight chamber" — the feature Williams calls important — and Miller's 1846 valve exists precisely "to receive the backward force of the steam." A fuller record, particularly US549484A (1895) and US312126A (1885, Steam oscillating valve), would likely strengthen the case and would be the natural candidates for a single‑reference or primary‑reference attack. Subject to the two caveats in § 0 — that § 103 is anachronistic for a 1900 filing, and that Google's "Similar Documents" list is not an examiner citation record — the combination is a straightforward, same‑field, same‑problem assembly of known rotary‑engine elements with a predictable result.