US 1303490

I'll verify against live sources before summarizing.

US Patent 1,303,490 — Verification Summary

Scope note on searching. My available tooling is general web search, not direct authenticated access to USPTO PatentCenter/PAIR or the CAFC docket system. I therefore cannot claim a complete docket sweep. What I can report: searches keyed to 1303490, "1,303,490", "US1303490", and 1303490 + CAFC/2026 docket returned no litigation, IPR, or Federal Circuit appeal involving this patent. No 2026 CAFC activity exists for it, which is expected given its status (below). I am flagging this as "not found" rather than "confirmed absent."

Number-collision warning (literal IDs, no auto-correction). A bare search for 1303490 surfaces at least three unrelated documents that must not be conflated with this patent:

• EP 1303490 (publication of application 01949475.6) — F. Hoffmann-La Roche AG, "N-oxides as prodrugs of 4-phenyl-pyridine NK1 receptor antagonists," filed 2001-07-09, granted 2008.
• PT 1303490 E and ES 2309075 T3 — national-phase translations of that same Roche EP case.
• Trademark no. 1303490 — BOLLORE ENERGY (Bolloré SE), cited in an EU ADR domain decision.

None of these is US 1,303,490.

Bibliographic data (from the authoritative patent text)

Discrepancy to flag explicitly (not auto-corrected): the OCR'd printed heading of the specification reads "APPLICATION FILED MAR. 23, 1912," while the specification body reads "Mar. 23, 1917" and the Google Patents metadata says 1917-03-23. The serial number 156,815 is consistent with a 1917 filing. I treat 1917-03-23 as correct, but the drawing-sheet line reading 1912 is a genuine, unresolved inconsistency in the source text.

Abstract

There is no abstract. This patent issued in 1919, well before abstracts were required on US patents. The functional substitute is the specification's statement of objects: (1) an exceedingly simple and effective construction whereby leakage is absolutely prevented and wear of the part readily compensated; (2) a packing readily removable from around the piston rod or shaft; and (3) a packing holder/container fitting the existing stuffing box, containing sectional wooden rings tightened around the rod by springs, arranged so that on the pressure stroke fluid entering the container acts on the packing to tighten it further against the rod.

The disclosed invention (plain language)

A two-piece sleeve container (joined by screws c) drops snugly into a conventional stuffing box a. Its bore is slightly larger than piston rod b and is cut with a series of parallel annular grooves d, d¹, d². Each groove holds a packing ring f split into two halves; the preferred material is a lubricating wood such as lignum vitae, chosen for its beneficial effect on the rod surface and its ability to self-adjust to a tight fit. Each ring's normal inner diameter is slightly smaller than the rod, so the rod expands the rings, and split spring rings g of approximately the ring width compress them back onto the rod. Joint sealing is handled by lead (or other pliable) rings h with diametrically opposite flaps h'; each h lies flat against one side of a packing ring and its flaps bend over and through circumferential grooves f' cut at the abutting ends of the two ring halves, where the spring rings g press them tightly over the joints. A lead gasket i between the rear of the container and the inner end of the stuffing box seals on tightening of gland c. Figures: Fig. 1 longitudinal section in the stuffing box; Fig. 2 enlarged end view of the container; Fig. 3 section on line 3–3 of Fig. 2; Fig. 4 end view of a sectional packing ring; Fig. 5 the opposite end of that ring.

Independent claims — plain-language overview

All three claims are independent; there are no dependent claims. Claim 1's text as printed in the source is truncated at its preamble (it begins mid-sentence at "larger in diameter than that of the said piston rod…"), so its opening limitation must be inferred from claims 2–3 and the specification; I note this rather than reconstructing it as if verbatim.

Claim 1 — A packing container for a stuffing box and piston rod, having: a sleeve whose bore is slightly larger in diameter than the rod and is formed with a number of parallel annular grooves; a two-half split ring in each groove; a spring encircling each packing ring to close it tightly on the rod; and, for each packing ring, a flapped ring with diametrically opposite flaps that bears flatly against one side of the packing ring and whose flaps close the crevices at the abutting ends of the two half-sections. Core idea: multiple ganged split rings, each spring-loaded, each with its own flap seal at the split.

Claim 2 — Same combination, with these express limitations: the sleeve is made of two sections removably joined and adapted to snugly fit the stuffing box; the bore is slightly larger than the rod and grooved; a two-half packing ring sits in each groove with its inner diameter slightly smaller than the rod (so it must be expanded onto the rod); a spring ring encircles the two halves; and for each packing ring an auxiliary flapped ring bears flatly against one side and closes the crevices at the abutting ends. Core idea: claim 1's structure plus the removability feature and the deliberate interference fit. Caveat: the printed claim says the ring's inner diameter is "slightly smaller than the diameter of said piston ring," which appears to be an error for "piston rod" (the specification consistently says piston rod). I flag it as an apparent defect in the printed claim text.

Claim 3 — Same combination, with the circumferential grooves expressly recited: the sleeve is a two-piece removable sleeve with parallel annular grooves; each groove holds a two-section packing ring having circumferential grooves at the adjoining ends of its sections; a spring encircles each ring's two sections; and a diametrically-flapped ring bears against one side of each packing ring with its flaps engaging those circumferential grooves and closing the crevices between the abutting ends. Core idea: the most structurally specific version — the flap-to-groove interlock at the split is a positive claim element.

Claim laddering. The three claims differ mainly in how much of the joint-sealing mechanism is recited: Claim 1 recites flapped rings generically; Claim 2 adds the removable two-section sleeve and the interference-fit dimension; Claim 3 adds the circumferential end grooves that the flaps engage. That progression is useful if the validity of any one claim is later tested by pre-1917 rod-packing art — the source lists dozens of similar documents (e.g., US 574,353; US 450,518; US 738,043; US 990,587; US 1,034,953; US 1,007,283; US 866,062).

Points of uncertainty

• Claim 1's preamble is missing in the available text; I did not fabricate it.
• "Piston ring" vs. "piston rod" in claim 2 appears to be a typographical error, but I have reported the claim as printed.
• Filing-year inconsistency (1912 in the drawing heading vs. 1917 elsewhere) is unresolved.
• No litigation or CAFC 2026 docket entry was found, but I could not query the courts' systems directly — treat this as an absence of evidence from open-web searching, not a certified negative.
• The patent has been expired since 1936, so any 2026 enforcement activity would be legally impossible regardless of docket results.

I'll search litigation databases for this specific patent number.

Let me search the litigation portals directly.

Litigation Search: US Patent 1,303,490

Bottom line: No litigation is known or discoverable involving US Patent 1,303,490.

What I searched

I queried for the specific number as literally instructed (1303490, US1303490, 1,303,490) combined with litigation-oriented terms (litigation, infringement, lawsuit, PACER, docket, Unified Patents caselist), and I attempted to reach the sources you named (portal.unifiedpatents.com litigation caselist, PACER/CAFC-oriented results).

Result

No case, docket entry, complaint, PTAB/IPR proceeding, or CAFC appeal was found naming US Patent 1,303,490. I cannot provide plaintiff, defendant, jurisdiction, case number, filing date, or outcome, because no such case appears in the sources retrieved. I will not fabricate case details.

Important caution — number collisions (do not confuse these with US 1,303,490)

Every search return for "1303490" was a different right, in a different office or register. These are not US Patent 1,303,490 and must not be conflated with it:

None of these is the US patent at issue. I am flagging them precisely because a literal number search surfaces them and they could be mistaken for the patent you asked about.

Contextual note on the patent itself (from the authoritative full text)

US Patent 1,303,490, "Packing for piston-rods or other fluid-engines," inventor Thomas M. Mallon (Philadelphia, PA), assignor of one-half to Edward A. Mallon (Brooklyn, NY):

• Application filed March 23, 1917 (Serial No. 156,815; application No. US15681517A)
• Patent granted May 13, 1919
• Anticipated expiration May 13, 1936; legal status listed as "Expired – Lifetime"
• Claims 1–3 cover a two-section sleeve packing container with annular grooves, split lignum vitae packing rings, spring rings, and lead auxiliary rings with diametrically opposite flaps sealing the ring joints

A patent whose term expired in 1936 (and which predates modern patent litigation reporting entirely) is an unlikely litigation candidate, which is consistent with the absence of any discoverable case. This is context, however, not proof of litigation — the operative finding is simply that no litigation was found.

Conclusion

• Known litigation involving US Patent 1,303,490: none found.
• If you have a specific docket number, court, or party name you believe is associated with this patent, provide it and I can target the search more precisely; the number standing alone returns no litigation records.

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

Proceedings overview

Total AIA trial proceedings on file for US 1,303,490: zero — no IPRs, no PGRs, no CBMs, none active, none settled, none with a final written decision, and none with an institution denial. The bottom-line defensive posture is therefore not "hardened patent" and not "claims canceled" — it is "the patent is expired, publicly dedicated, and has never been tested at the PTAB." A demand letter asserting this patent in 2026 is facially frivolous, but you cannot point to any PTAB cancellation to defeat it; you defeat it with the expiration date on the face of the patent instead.

Sourcing note: the structured "PTAB proceedings on file" block (USPTO Open Data Portal, most recent ingest) returns an empty set, and my independent web searches surfaced nothing to the contrary. The Google Patents record for US 1,303,490 (https://patents.google.com/patent/US1303490/en) shows legal status "Expired - Lifetime" with an anticipated expiration of 1936-05-13.

No AIA trial proceedings on file — verification and near-miss disambiguation

There is no {PROCEEDING_NUMBER} to report, and I will not manufacture one. What I can document is what I ruled out, because web searches on a seven-digit patent number produce a lot of false positives:

• Near-miss confusion risk (do not cite these as this patent): U.S. Patent 6,067,349 (IPR2021-00573), U.S. Patent 8,861,349 (Red Hat v. Competitive Access Systems, IPR2024 docket), U.S. Patent 11,292,349 (Samsung v. Mojo Mobility, IPR2023-01090), and U.S. Patent 9,535,490 (IPR2018-01261/-01344) all appear in PTAB records and all contain the digit string "349." None of them is US 1,303,490. Likewise, EP 1,303,490 B1 (F. Hoffmann-La Roche, NK1-receptor prodrugs) is a wholly unrelated European pharmaceutical patent that dominates search results.

• Procedural impossibility for two of the three AIA trial types, on this record:

  • PGR requires the challenged patent to be subject to the first-inventor-to-file provisions. US 1,303,490 was filed 1917-03-23 and granted 1919-05-13 — it is a pre-AIA patent and is categorically outside PGR eligibility.
  • CBM was limited to covered business method patents (financial products/services) and, in any event, sunset on 2020-09-16 under § 18 of the AIA. Not available.
  • IPR (§ 311) has no patent-age bar and technically could have been filed against this patent after 2012-09-16 — nothing has been. There is also no practical petitioner: the patent expired long before the AIA existed.

• Related-but-different proceeding type on the same inventor name: Mallon v. William C. Gregg & Co. (3d Cir. era decision, available via CourtListener) involved a Mallon patent on an endless-chain cane rake — a different patent and a district court appeal, not a PTAB proceeding. Do not conflate it with 1,303,490's inventor Thomas M. Mallon.

• Judge panel: none — no proceeding.

• Petition grounds: none.

• Institution decision: none.

• Final Written Decision: none. Therefore no claim of US 1,303,490 has ever been canceled, and none has ever been sustained, by the PTAB. Both statements matter; the claims are untested at the Board.

• Settlement / termination: none.

• Appeal: none. No CAFC docket exists for this patent.

• Defensive value: An assertion of US 1,303,490 today is answered by the § 154 term. Under the law in force when it granted, the term was 17 years from grant: 1919-05-13 + 17 years = 1936-05-13, which is exactly the "Anticipated expiration" date the USPTO record shows. Combined with the 6-year damages lookback of 35 U.S.C. § 286, there is no period of enforceable, compensable conduct left. Any pre-suit demand built on claims 1, 2, or 3 is not merely weak — it is unsupported by an enforceable right.

Strategic summary

Claim status: there is no PTAB narrowing to rely on. US 1,303,490 issued with three claims. Claim 2 and claim 3 are recited cleanly in the printed specification: claim 2 covers the combination with a stuffing box and piston rod of the two-section sleeve container with annular grooves, a split packing ring in each groove whose inner diameter is slightly smaller than the rod, a spring ring, and a flapped auxiliary ring; claim 3 recites the same combination with the circumferential grooves at the adjoining ends of the ring sections receiving the auxiliary ring flaps. Claim 1 as OCR'd is truncated (it opens "larger in diameter than that of the said pi ton rod…", with the preamble lost in the scan), so I will not characterize its exact scope beyond noting it claims the rings-and-springs combination. To be explicit about the task's framing: no claims are CANCELED; none are SUSTAINED; all three are UNTESTED by the PTAB. The patent's effective end is a matter of statutory term, not adjudication.

Estoppel landscape: § 315(e)(2) estoppel is a non-issue here. Estoppel attaches only to a petitioner (and its privies) in an IPR that results in a final written decision under § 318(a). Because no IPR was ever filed, no party is estopped from raising any prior-art ground — every § 102 and § 103 reference is theoretically available to a defendant or a would-be petitioner. That is cold comfort in the other direction, however: it also means there is no adjudicated invalidity judgment to invoke defensively. If you are on the receiving end of an assertion, your invalidity case would have to be built from scratch in district court (or a DJ action), on a 1910s-era mechanical packing art — a technically easy but unnecessary exercise, since the expiration date resolves the matter faster and cheaper than any invalidity theory.

Pattern signals: none. No petitioner has filed even once against this patent, let alone serially; the patent owner has never appealed anything to the Federal Circuit; there is no defensive aggregator (Unified Patents or similar) in the chain; and there is no litigation family. The current assignee of record is Edward A. Mallon (assignee of one-half), with inventor Thomas M. Mallon of Philadelphia, Pennsylvania — an assignee arrangement from 1919 with no modern corporate owner identified. The complete absence of PTAB activity here is not the "well-asserted patents eventually attract IPRs" signal. It is the opposite: this is an artifact patent whose enforceability window closed in 1936, decades before the AIA created the PTAB trial regime (2012-09-16) or the pre-AIA inter partes reexamination regime (1999-11-29). No rational petitioner ever had an economic reason to file.

One literal-reading caution. The drawing sheet caption as OCR'd from the printed patent reads "APPLICATION FILED MAR. 23, 1912," while the specification states "Application filed March 23, 1917. Serial No. 156,815," and the USPTO record gives the filing date as 1917-03-23. I flag this rather than silently harmonizing it, per the instruction to interpret identifiers literally. The discrepancy does not change the analysis: either date yields a 17-year term expiring well before the AIA existed.

Recommended next steps

• If you are a defendant and you have received a demand citing US 1,303,490, lead with expiration, not invalidity. There is no FWD to link to — no PTAB decision exists for this patent — so the dispositive document is the patent itself: https://patents.google.com/patent/US1303490/en, showing publication 1919-05-13, filing 1917-03-23, and legal status "Expired - Lifetime" with anticipated expiration 1936-05-13. Pair that with 35 U.S.C. § 286 (no damages for conduct more than six years before suit) and § 282's presumption-of-validity framework, which is irrelevant when there is no enforceable term left.
• Preserve the record of the assertion. If a modern entity is sending letters on a 1919 patent, the letters themselves (not any PTAB outcome) are the evidence that matters — for a declaratory-judgment action, a Rule 11 motion, or state-law unfair-competition / patent-troll claims. Note that a DJ plaintiff must still establish an actual controversy; a demand letter plus the patent's expired status generally supports one, but this is worth a short analysis rather than an assumption.
• There are no trial-stage milestones to track. No institution decision deadline, no oral hearing, no statutory one-year § 316(a)(11) FWD deadline, and no § 315(b) one-year bar clock is running, because no petition exists. If you are evaluating filing an IPR yourself, understand that an IPR against an expired patent is legally permissible under § 311 but serves an unusual purpose (claim-scope confirmation or estoppel positioning), and here it would be a pointless expenditure against a patent with no remaining term.
• Do not represent to a court or an adversary that "the claims have been canceled" or that the patent "survived" an IPR. Neither is true, and both would be fabrications. The accurate statement is: US 1,303,490 expired no later than 1936-05-13, has never been the subject of any AIA trial proceeding, and no PTAB or Federal Circuit decision construes any of its claims.

Verification of the null result. The USPTO ODP structured block is the canonical source and reports no AIA trials. My web searches of PTAB E2E material, PTAB petition documents, and CourtListener returned only unrelated patents sharing the "349" number string and an unrelated EP 1,303,490. I could not find any proceeding I can name — and I will not invent a proceeding number, panel, or disposition to fill the template. If you need a belt-and-suspenders confirmation, run the patent number directly in PTAB E2E at https://ptacts.uspto.gov/ and the PTAB decisions archive at https://www.uspto.gov/patents/ptab/decisions, and a CourtListener search at https://www.courtlistener.com/?q=%221303490%22; I expect all three to return zero for this patent.

I'll check the USPTO assignment records and related sources before reconstructing the chain.

Inventors

• Only one inventor is named. The two other natural persons on the document — Edw. J. Wardle and John W. Kingsmill — are attested witnesses, not inventors, and must not be listed as such.
• Employer: no corporate employer is named anywhere in the specification, on the face of the patent, or in any record I could retrieve. The claims' environment (steam-engine cylinders, stuffing boxes, piston rods b, gland c) places the inventor in the mechanical/steam-engine field, but that is a field inference, not an employer finding. I will not name a company.
• Departure pattern: inapplicable/unavailable. The "all inventors depart the original assignee within 12 months" tell cannot be evaluated for a 1917 filing, because there is no assignee entity to depart from (see below) and no personnel records survive in any indexed source.

Name-collision warning (literal ID discipline). Targeted searching on the inventor's surname surfaces Mallon v. William C. Gregg & Co. (courtlistener.com, Harvard PDF 8773861) — a cane-car-dumping / endless-chain rake case about a patent to Mallon. That is a different Mallon and a different patent. It is not Thomas M. Mallon, not Philadelphia, not a packing, and not US 1,303,490. I am flagging it because it is the first thing a "Mallon + patent + litigation" search returns and it would be an easy false attribution. It should not be used as evidence of any litigation over this patent.

Original assignee

There is no corporate original assignee. This is the single most important structural fact in the whole ownership analysis, and it changes how every downstream NPE test must be scored.

• The face of the patent reads: "THOMAS M. MALLON, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO EDWARD A. MALLON, OF BROOKLYN, NEW YORK."
• Google Patents accordingly lists the original assignee and the current assignee as EDWARD A. MALLON — i.e., an individual co-owner holding an undivided one-half interest, not a company.
• Line of business: none assignable. There is no company to have one.
• Product embodying the claims: no evidence of any commercial product, licensee, or manufacture found. The specification recites that the sleeve is "adapted to snugly fit in the stuffing box and now used" and that the gasket seals "on tightening the gland c" — i.e., the invention is described as a retrofit part for existing engines. That is descriptive of intended use, not proof of a shipped product. Unclear / not found.
• Current status: no corporate status to report. Both named individuals are long deceased; no successor entity appears in any record.
• Related-half-interest implication: the patent was owned 50/50 by two individuals sharing a surname (Thomas M. Mallon and Edward A. Mallon). That is the classic early-20th-century inventor + partner/financier co-ownership pattern, not an employer-employee assignment. It means there is no "operating assignee" to pass the patent to an NPE later.

Assignment timeline

Finding: the USPTO Assignment Center / Patent Assignment Search returned no post-issuance assignment records for US 1,303,490, and I retrieved no reel/frame entry of any kind for it.

I must be precise about what that does and does not mean:

1. What I searched. Queries keyed to 1303490, US1303490, "1,303,490", and Mallon + 1,303,490 + assignment, aimed at the Assignment Center (assignmentcenter.uspto.gov) and its indexed mirror (assignment.uspto.gov/patent/index.html). My tooling is general web search — I could not perform an authenticated, in-database query against assignmentcenter.uspto.gov itself, which is a dynamic application. So this is an absence-of-evidence finding, not a certified negative, exactly as I flagged for the litigation sweep in the prior section.
2. Coverage caveat that matters specifically here. The electronic Patent Assignment Search is not a reliable index for recordings made in 1917–1919. Records of that era live on microfilm and are only patchily represented in the online database. Even if a 1917 assignment document exists on film, the online tooling may not surface it, and no reel/frame number was returned to me. I therefore cannot populate the standard reel NN/NNNN fields for this patent — and I will not invent them.
3. The one transfer that is affirmatively documented is the pre-issuance half-interest assignment recited on the printed patent itself ("assignor of one-half to Edward A. Mallon, of Brooklyn, New York"). Execution date and recording date are not stated in the material available to me. It cannot be dated from the face of the patent, and I have no correspondent of record for it. Treat it as an undocumented-in-detail origin conveyance, not a reel/frame-cited event.
4. No subsequent events of any kind were found — no Assignment, Security Agreement, Merger, Change of Name, License, Release, or Correction recorded after issuance; no correspondent of record to capture; no correspondent recurrence to flag across the chain.

Accordingly, per the operating rule for this task: the Assignment Center has no discoverable records for this patent, so I stop the reel-by-reel enumeration here. There is nothing to list chronologically beyond the single origin conveyance above.

Cross-references attempted, with results:

• Google Patents legal events: shows only filing (1917-03-23), grant (1919-05-13), anticipated expiration (1936-05-13), status "Expired – Lifetime," family ID 3371025, single US member. No assignment events listed.
• SEC filings (10-K / 8-K): not applicable — no public company appears anywhere in this chain. Nothing to look up.
• PEDS / ODP: not applicable / no assignment content — these are prosecution-data systems for an application closed in 1919.
• RPX and Unified Patents asserter directories: searched; no match for either 1,303,490, the patent family, or either Mallon.

Timeline diagram

timeline
    title Ownership of US 1303490
    1917 : Application filed by Thomas M Mallon
    1919 : Patent issued
         : Half interest held by Edward A Mallon
    1936 : Patent term expired

NPE / troll-pattern signals

Scored against the record as it stands. Because the chain contains no post-issuance assignments at all, most of these tests fail on the threshold requirement of "a transfer to point to."

One honest near-miss worth recording (deliberately not scored as a signal). The threshold event in this chain — inventor grants an undivided one-half interest to a same-surname individual in a different city — superficially resembles an early monetization/financing arrangement. I am not treating it as an NPE signal: half-interest co-ownership among individuals was routine practice in 1917, there is no evidence of licensing activity, no assertion, no assignment to an asserting entity, and no correspondent or reel/frame, and "could be a financing arrangement" is precisely the kind of inference the task instructs me not to make. Recording it here only so the reasoning is auditable.

Verdict

Insufficient data — the chain consists of only the original conveyance (the one-half interest to Edward A. Mallon recited on the face of the patent), with no discoverable recorded post-issuance assignment and no reel/frame or correspondent to cite.

That collapse into "insufficient data" is not an NPE indicator, and the distinction matters: every one of the eight troll-pattern tests fails at the threshold for want of a transfer, not for want of evidence about a transfer. The patent issued 1919-05-13, carried a 17-year term, and expired 1936-05-13 with essentially no assertion or commercialization history. Even setting aside the 110-year age of the asset, a patent whose term lapsed in 1936 is legally incapable of being asserted in 2026, so there is no live NPE question to answer. Moderate/high-confidence NPE calls would require at least one recorded shell-entity or repeat-correspondent entry, and none exists or can be sourced.

Verification link: USPTO Assignment Center — search by patent number 1303490; mirror index at assignment.uspto.gov/patent/index.html. Note the microfilm-era coverage caveat in the Assignment timeline section: a null result there for a 1917–1919 recording is weaker evidence than a null result for a modern patent, and I have flagged it as such rather than treating it as a confirmed absence of any 1917 recording.

Standing caveats carried forward from the prior sections: (a) the printed heading's "MAR. 23, 1912" conflicts with the 1917 filing date used throughout — if the 1912 date were correct, the timing of the half-interest conveyance relative to filing would shift, and that inconsistency remains unresolved; (b) claim 1's preamble is missing from the available text; (c) claim 2 recites "piston ring" where "piston rod" is presumably intended. None of these affects the ownership conclusion.

I'll run targeted searches to verify what citation data actually exists for this patent number before I answer.

Direct answer first: there are no patent citations of record for US 1,303,490

I searched for citation data on this specific number (1303490, US1303490, US1303490A, "1,303,490" + citations/references/prior art) and the finding is negative in a specific and important way:

The record for US 1,303,490 contains no "References Cited" list and no "Cited By" list. What exists on Google Patents is a "Similar Documents" table, which is an algorithmic text-similarity output generated by Google — it is not a list of examiner citations, not a list of references cited against the patent, and not prior art of record. I can confirm one asymmetrical data point: the Google Patents page for US 2,064,235 lists US1303490A among its Similar Documents, while US1303490A's own page shows no forward-citation ("Cited By") block. That is consistent with the citation index simply not being populated for this 1919 document.

Why this is expected, and not a search failure: US 1,303,490 issued 13 May 1919. Front-page "References Cited" listings were not a feature of US patents until decades later, and the printed specification text supplied here (authoritative) contains no such section — it runs from "What I claim…" straight into the claims and the signature block. So the honest answer to "look at each patent citation for 1303490" is: there are none to look at. I will not manufacture a citation table.

I also note the prior sections already flagged the number collisions (EP 1303490 / Roche; PT 1303490 E; ES 2309075 T3; trademark 1303490 / BOLLORÉ ENERGY). Those are not this patent and I won't repeat them.

Contradictions I must flag before proceeding

1. Date conflict between the task header and my operating context. The task states "Current Date: April 26, 2026"; my session metadata and the source fetch stamp say 2026-09-30. I am treating the discrepancy as unresolved and will not silently pick one.
2. "Search the USPTO database" overstates my tooling. I have general web search, not authenticated USPTO PatentCenter / Patent Public Search / Global Dossier query access. My results are what the open web surfaces, which is why the finding is "not found in retrieved sources," not "certified absent from the register." This is the same limitation flagged in the two earlier sections — no contradiction, just continuity.
3. Filing-date inconsistency (carried over, unresolved). Earlier sections flagged that the OCR'd drawing heading reads "APPLICATION FILED MAR. 23, 1912" while the specification body reads "March 23, 1917, Serial No. 156,815" and Google metadata says 1917-03-23. Nothing in this round of searching resolves it. It matters here because it sets the § 102 bar date.

Substitute analysis: the closest available art set

Since no citation-of-record list exists, the only defensible approach is to evaluate the "Similar Documents" set as candidate analogous art, with an explicit caveat: I did not retrieve or read the full text of these references in this session. Everything below is derived from the reference titles, dates, and the shared classification (F16J 15/26–15/28: stuffing boxes for rigid/metal sealing rings). Treat the element-overlap column as hypotheses requiring full-text verification, not as findings.

Legal framing. For a 1917 filing, the controlling anticipation provision was the pre-1952 statute (R.S. § 4886, carried into the 1870/1897 Act framework; recodified as 35 U.S.C. § 102 only in 1952). Functionally the analysis maps onto today's pre-AIA § 102(a)/(b): references published more than one year before 23 March 1917 — i.e., before 23 March 1916 — are § 102(b) candidates; publications between 23 March 1916 and 23 March 1917 would be § 102(a) candidates only. Non-obviousness (§ 103) did not exist as a statutory ground in 1919, so the correct framing for this patent's era is anticipation, not obviousness.

Critical trap in the "Similar Documents" list

Two entries post-date the patent and are therefore not prior art at all, despite appearing in the similarity table:

Anyone treating Google's "Similar Documents" as a prior-art list will wrongly import these. Flagging explicitly.

Candidate pre-1916 art (the § 102(b) set)

All of the following published more than one year before the 23 March 1917 filing, so each is a facial § 102(b) candidate. Dates are the publication dates as listed in the source; I have not independently verified each against the register.

An additional lead not in the similarity table

While searching I encountered a second-hand reference to US 1,028,758, described in the background of US 4,289,317 as a prior-art device "where the pressure of fluid acts to force the packing ring against the shaft." That is precisely the pressure-assisted-tightening principle the specification of US 1,303,490 asserts ("when during a pressure stroke steam… leaks through into the container, it will… act on the springs… assisting the latter in tightening the packing rings"). Important caveat — and this is a conclusion, not a hedge: that pressure-actuation feature appears only in the specification's statement of objects and in the description. It is not recited in any of claims 1, 2, or 3. Consequently US 1,028,758 (or any other pressure-actuated reference) cannot anticipate the claims as written, even if it fully discloses the principle; it would at most bear on the disclosure, not the claims. I did not verify US 1,028,758's bibliographic data or text, so treat the citation itself as a lead to confirm.

Claim-by-claim anticipation assessment

I'll be blunt about the epistemic status. I cannot responsibly assert that any single reference anticipates any specific claim, because I have not read the references, and for that I need each reference's own full text — which my tooling did not return. What I can do is map the claim limitations and identify which references are the ones to pull first.

The limitations that must be met, claim by claim

Reading of the claim ladder. The single most invention-defining limitation across all three claims is the last structural one — the flapped auxiliary ring whose flaps close the crevices at the split joints of a two-half packing ring. That is the element I would expect to be the hardest to anticipate, and correspondingly it is the element I most need full texts to check. The strongest candidates for the surrounding hardware (grooved multi-ring carrier sleeve + spring-closed split rings) are US 1,034,953 (1912), US 990,587 (1911), and US 1,007,283 (1911) — the closest in time to the one-year bar and squarely in the metallic rod-packing subclass. The best candidate for the removable two-section container limitation uniquely recited in claims 2 and 3 is US 654,881 (1900, "Stuffing-box"), with US 866,062 (1907) as the alternative. For a title-level knockout candidate, pull US 695,195 (1902) first.

Preamble caveat. Claim 1's printed text is truncated at its preamble — it begins mid-sentence at "larger in diameter than that of the said piston rod." Any anticipation analysis of claim 1 must be built on the inferred preamble, and I'm carrying that forward as a documented defect rather than reconstructing it silently. This is consistent with the earlier summary; no contradiction.

Printing defect in claim 2, carried forward. Claim 2 recites the ring's inner diameter as "slightly smaller than the diameter of said piston ring," which the specification's consistent usage indicates should be "piston rod." I am reporting the claim as printed. This matters for § 102 because a reference discloses the limitation only if it teaches the interference fit against the rod — the literal claim text is almost certainly erroneous, but I flag rather than fix it.

What I'd need to close this out

To convert the hypotheses above into actual § 102 conclusions I would need, for each candidate: (a) the full printed specification and claims, (b) the drawing sheets, and (c) confirmation of publication date against the register. My searches for those full texts on this number returned no citation-quality data. If you can supply the reference PDFs, or if you want me to focus on a shortlist — my recommended order is US 1,034,953 → US 990,587 → US 695,195 → US 654,881 → US 1,007,283 → US 1,028,758 — I can run the element-by-element comparison properly.

Bottom line

• USPTO record for 1303490: resolves to US 1,303,490 A, Mallon, filing 1917-03-23, issue 1919-05-13, expired 1936-05-13. No conflicting hits for that number were found in the retrieved sources.
• Patent citations of record: none. No "References Cited," no "Cited By." The patent predates citation listings; the specification text has no such section.
• Best available substitute: Google's "Similar Documents" set, of which 23 entries are pre-1916 and thus facial § 102(b) candidates, and 2 entries (US 1,635,482; US 1,958,221) are post-dated and are not prior art.
• Anticipation conclusions: none asserted. Element-level mapping and a prioritized pull list are provided instead; asserting anticipatory effect without reading the references would be fabrication.
• Unresolved contradictions: 1912 vs 1917 filing heading; 2026-04-26 vs 2026-09-30 "current date"; and the practical limit that I cannot query USPTO systems directly.

I'll pull the actual content of the key prior-art references listed in the "Similar Documents" section so the § 103 analysis is grounded rather than generic.

Good — I have US 990,587 and US 574,353 detailed. Let me pull the remaining key references.

Obviousness Analysis — US 1,303,490 under 35 U.S.C. § 103

Note on scope, and how this builds on the prior sections. The earlier sections established the bibliographic record, the claim set (three independent claims; claim 1's preamble truncated in the source; "piston ring" typo in claim 2), the 1912/1917 filing-date discrepancy, and the absence of litigation. I do not repeat those here. This section takes the claim limitations as already construed and asks only whether they would have been obvious over the prior art, using the "Similar Documents" list on the Google Patents page as the operative prior-art universe, as instructed.

1. Legal frame (and one unavoidable caveat)

• Which § 103 applies. The application was filed 1917-03-23 and issued 1919-05-13. Section 103 was not enacted until the Patent Act of 1952 (and substantially rewritten in 2011). Any § 103 analysis of this patent is therefore retrospective, applying the Graham v. John Deere factors (scope/content of prior art; differences from the claims; PHOSITA level; objective indicia) to a 1917 fact pattern.
• Standard-of-invention sensitivity. A 1917-era court would have tested this under the then-prevailing "invention" standard, later hardened into the "flash of genius" test of Cuno Engineering v. Automatic Devices (1941), which KSR Int'l v. Teleflex (2007) expressly repudiated. The analysis below applies the modern, flexible KSR/TSM approach. Reasonable readers should note that the same claims might well have survived a 1917 or 1940s court that no modern court would now sustain. That is a feature of the exercise, not a defect in it.
• PHOSITA. A mechanical engineer or skilled engine-erector with several years' experience designing steam-engine stuffing boxes and rod packings; familiar with metallic, semi-metallic, and fibrous packings, split rings, gland loading, and pressure-assisted (self-setting) packing; capable of routine machining (grooving a sleeve, cutting rings in halves, making flaps).

2. Prior-art universe, screened

From the Google "Similar Documents" list, two entries post-date the 1917 filing and are therefore not prior art — they are merely cited as similar:

All remaining listed documents pre-date the filing. Full text verified by me in this session (via search/patentimages):

Supplementary art found by search that is not in the Google list but is squarely on point (I flag this so it is not mistaken for a listed reference):

Unverified listed references. I retrieved only titles/dates for: US 450,518 (Stuffing-box, 1891); US 249,560 (1881); US 583,451 (Rod-packing, 1897); US 387,900 (1888); US 595,675 (1897); US 654,881 (Stuffing-box, 1900); US 332,856 (1885); US 967,235 (Packing, 1910); US 660,399 (Propeller-shaft bearing, 1900); US 846,668 (Metallic piston-packing, 1907); US 745,908 (Piston-rod packing, 1903); US 390,225 (1888); US 671,681 (Metallic rod-packing, 1901); US 695,195 (1902); US 1,034,953 (Rod-packing, 1912); US 1,007,283 (Metallic piston-rod packing, 1911); US 603,588 (1898); US 401,984 (Rod-packing, 1889); US 775,194 (Metallic packing, 1904). I do not attribute any specific disclosure to these; any reliance on them should be verified against full text.

Mismatch to flag. My search keyed to US 738,043 (Rod-packing, 1903-09-01) returned the full text of US 731,304 (Howe, Rod-packing, filed 1903-02-25, issued 1903-06-16) — a different patent. Howe's disclosure (self-setting contractible metal rings responding to cylinder pressure; segmented rings arranged to "break joint"; ring sections retained by dowel pins) is useful analogous art, but I do not attribute it to US 738,043. Howe is also not in the Google list.

3. Claim element breakdown

Limitations below are keyed to the source text. Claim 1's preamble is missing from the source; the bracketed preamble is inferred from claims 2–3 and flagged as such.

4. Element-by-element mapping to the art

5. The combinations, and why the artisan would make them

Combination A (against claim 1): Potts '587 as primary + Clark '107 as secondary.
Potts supplies the sleeve container, the two-half ring, the joint-spanning pieces, and pressure-assisted closure; Clark supplies the spring encircling a sectional ring to hold it tight on the rod and the plural-ring cage in one housing. Both are rod-packings for steam engines; both address the identical problem (fluid escaping along the rod and through the ring splits); both use sectional rings that must be collapsed onto the rod. The motivation is essentially self-evident: a worker adopting Clark's spring-closed sectional rings inside Potts' sleeve would immediately confront the fact that a spring-closed split ring has two open joints, and the reference that already solves exactly that problem — Potts' pieces 12 covering the section joints, Cook's overlapping bevel, Cook's anti-coincidence lugs — is in the same field. Putting the split ring's own covering plate on a flat annular washer with two diametrically opposed flaps (one per joint) is a mechanical design choice requiring no invention, and the result (leak paths closed, wear taken up by the spring) is entirely predictable.

Combination B (against claim 2): A + Garlock '353.
Claim 2 adds removability of the sleeve and the interference fit. Removability is expressly taught by Garlock ("the part F being secured to the stuffing-box by ordinary stud-bolts a, is removable therefrom"), and the two-section sleeve is Garlock's/ Potts' assembly expedient. The interference fit ("inner diameter… slightly smaller than the piston rod") is inherent in any spring-collapsed packing ring and is the stated purpose of Clark's springs ("a constant tight fit of the ring to the piston-rod"). The substitution of a spring ring for Potts' soft packing as the means pressing the joint cover is an obvious substitution of equivalents — both perform the identical function (radially clamping the ring/cover onto the rod/sleeve) by identical means (radial compression).

Combination C (against claim 3): Potts '587 (+ Clark '107) with the groove interlock emphasized.
Claim 3's extra limitation — circumferential grooves at the adjoining ends of the ring sections engaged by the flaps — reads almost directly onto Potts: recesses/pockets 11 in the contiguous edges of sections 9/10, into which the end portions of the segmental pieces 12 extend. The only difference is that Mallon puts the grooves and flaps on the packing ring halves rather than on the sleeve halves. Merely relocating a known joint-covering/groove arrangement from the sleeve to the ring it encloses — where both are the split elements whose joint must be sealed — is an obvious design variant with no new result.

Combination D (alternative primary): Bryant '445 or Clark '107 + Potts.
Bryant '445 already discloses a shell/casing insert, a split conical ring, a spring, and pressure-actuated clamping — i.e., most of claim 1's architecture. Substituting/adding Potts' joint-covering pieces to seal the split is the same motivation as in Combination A.

Why combine at all — KSR rationales.

1. Same field, same problem, same solution mechanism. All references are stuffing-box/rod-packing art; the Google classification F16J 15/28 (stuffing boxes with rigid, metal sealing rings) captures the family.
2. The leak path at a ring split is intrinsic to the structure, so sealing it is a recognized design objective — not a leap. Cook '512 states the joint-coincidence problem expressly ("a straight passage for steam").
3. Predictable, enumerated solutions. KSR: where the art identifies a finite number of identified, predictable solutions, a PHOSITA has good reason to pursue them.
4. Substitution of known equivalents (spring ring for packing, ring-mounted joint cover for sleeve-mounted joint cover) with no unexpected result.
5. Crowded art. The Google page lists ~25 "similar documents," nearly all pre-1917 rod packings — a mature, well-trodden field that supports the "ordinary innovation" characterization.

6. Where the claims might survive (the honest counterweight)

• The specific geometry of the auxiliary ring. No verified reference shows a single flat annular plate carrying exactly two diametrically opposed down-turned flaps that bend over both joints of a two-half packing ring. Potts' pieces 12 are plural segmental inserts; Cook's seal is an overlapping bevel plus lugs, not a flapped washer. A patentee could argue that the claimed element is a distinct structural species, and that the particular combination — flap-and-groove closing pressed by a spring ring rather than by gland pressure or soft packing — is not literally shown.
• Claim 1 does not require the grooves (3a) and claim 2 recites the interference fit expressly; only claim 3 requires the flap/groove interlock. So a validity challenge is strongest against claim 1 (broadest) and weakest against claim 3 (most structure).
• The pre-1917 standard-of-invention issue discussed in §1 cuts in the patentee's favor if an old-law lens is applied.
• Material evidence. The lignum-vitae preference and its "beneficial effect on the rod" are not claimed in any of claims 1–3, so no non-obviousness argument can be built on the material (and a material-substitution argument would fail anyway; note the presence in the same list of US 660,399, Propeller-shaft bearing, reflecting the known use of lignum vitae as a self-lubricating bearing material).

7. Objective indicia (secondary considerations)

None are available. The prior sections established that the patent expired in 1936 and that no litigation, license, commercial-success, long-felt-need, copying, or failure-of-others evidence was found. Under Graham, objective indicia are considered only when present and connected to the claimed invention; here the record supplies none. The specification's assertion of "absolutely" preventing leakage is uncorroborated attorney/ inventor argument, not evidence.

8. Conclusion

Bottom line: Applying modern § 103 standards, claims 1–3 of US 1,303,490 would most probably be held invalid as obvious over Potts & Weaver US 990,587 in view of Clark US 557,107, further in view of Garlock US 574,353 (claim 2) and Cook US 808,512 (claim 3) — with Bryant US 563,445 available as an alternative primary reference. Claim 3 is the most defensible, turning on whether relocating the known joint-sealing groove-and-cover arrangement from the sleeve to the packing ring is inventive — a proposition I doubt, but one where a genuine factual dispute exists.

Caveats limiting the confidence of this opinion: (i) I could not verify the full text of roughly two-thirds of the listed references; the analysis rests primarily on Potts '587, Garlock '353, Clark '107, Cook '512, and Bryant '445, all of which I did verify; (ii) claim 1's preamble is missing from the source and was inferred; (iii) the 1912 vs. 1917 filing-date inconsistency in the printed specification, if 1912 were correct, would not change the analysis (all cited art still antedates either date) but would shift the critical date; and (iv) § 103 post-dates this patent, so any real-world conclusion is necessarily retrospective.