US 4921417

I'll search for the requested information on US patent 4921417.

Let me run a couple more targeted searches to check for any litigation, PTAB, or assignment records specific to this patent number.

US Patent 4,921,417 — Summary

Source: Google Patents, https://patents.google.com/patent/[US4921417](/patent/US4921417)/en (fetched via search; full text reviewed). No USPTO litigation or CAFC 2026 docket activity for this number was found (see "Litigation check" below).

Bibliographic data

Abstract (as published)

A molding apparatus for molding a clay pigeon includes a bypass tube having a tip disposed in a blow orifice communicating with a cavity of a metal mold in the form of the clay pigeon. The bypass tube has a diameter smaller than that of the blow orifice, and compressed air that leads molding material in the blow orifice passes through it in order to supply the molding material (a mixture of at least sand and hardening agent) to the cavity, whereby corners and details of the cavity are satisfactorily filled with the molding material.

Plain-language overview of the sole independent claim (claim 1)

Claim 1 is an apparatus claim covering a clay-pigeon molding machine with these elements:

1. A tank holding the molding material — a mixture of at least sand and a hardening agent.
2. A compressor supplying compressed air into a duct connected to the upper portion of the tank.
3. A mold with a cavity shaped like the clay pigeon.
4. A blow orifice connecting the mold to the lower portion of the tank, so material can be blown from the tank into the mold.
5. A bypass tube, the key novel element:
   • its front end sits inside the blow orifice, parallel to the orifice;
   • its rear end sits inside the duct, parallel to the duct;
   • its diameter is smaller than both the duct and the blow orifice;
   • a portion of the compressor's air is diverted through it to "lead" (assist/entrain) the blowing of molding material through the blow orifice.
6. A pressure-regulating valve and/or a flow-rate-regulating valve located along the bypass tube (the claim uses "and/or," making either valve alone sufficient).

Practical reading: the invention is a low-cost retrofit-style fix for "short shots" — poorly filled mold corners — in a sand-and-binder clay-pigeon blow-molding machine. By inserting a narrow air-injection tube that bypasses part of the compressed air directly into the throat of the blow orifice, the sand/agent mixture is entrained and driven more forcefully into the fine details (stepped rim, groove lines) of the cavity. The claimed valves let the operator tune the bypass airflow.

Supporting disclosure highlights (for context, not claim scope)

• The bypass tube example in the specification: 7 mm inner diameter inside a 30 mm duct; mold heated to about 280 °C; compressed air at 2–4 kg/cm² for 2–3 seconds; sinter about 10 seconds.
• The patent also describes the molded clay pigeon itself (steps 2/3/4, an inverted-triangle protective projection 5 on the rim, optional screw-propeller-like radial groove lines 6 at 3.0 mm depth × 1.5 mm width in a 3.5 mm wall). These product features are described but not claimed in this patent.
• Prior art cited on the face: US 571,958; US 3,125,780; US 3,469,411; US 3,788,790; US 4,276,015 (Rogers, "Method and apparatus for molding clay pigeons and the like," assigned-area art); US 4,623,150; JP S61-162538; JP S63-317399.

Litigation check (USPTO / CAFC 2026)

I searched for litigation, PTAB, and appellate records tied to this number. No CAFC 2026 docket, IPR/PGR, or district-court case involving US 4,921,417 was found. The only hits for the numeric string "4921417" were false positives:

• SU/RU 4921417/27 — a Soviet/Russian application number for RU 2,011,902 C1, "Motor-axial bearing" (Gioev, Prikhod'ko, Akhverdiev). Completely unrelated technology and jurisdiction; this is an application serial number, not a US patent.
• CourtListener API id 4921417 — an internal financial-disclosure record ID, unrelated.

This absence is consistent with the record: the patent's term expired 2007-10-05 and it is marked "Expired – Lifetime," so live 2026 infringement litigation would be unexpected. Its only recorded forward citations are ES 2,144,935 A1, US 2004/0094454 A1 (and its US 7,067,050 / 7,393,449 / 7,625,479 continuations), and USD 750,728 S1.

Uncertainty flags

• Assignee identity: Google Patents lists the current assignee as "Sato Manufacturing Co., Ltd.," while the citation table in US 4,276,015 renders it "Sato Factory Co., Ltd." I am reporting both literally rather than choosing; the distinction may be a transliteration/name-change issue that I cannot resolve from the sources retrieved.
• I could not independently verify an assignment history or fee/maintenance record beyond the legal-events entries in Google Patents (fourth, eighth, and twelfth-year maintenance fees paid; no later events).
• The claim text above is taken literally, including its original "a pressure regulating valve and/or a flow rate regulating valve" phrasing.

Key URLs: https://patents.google.com/patent/US4921417/en · https://patents.justia.com/patent/4921417 · https://patentimages.storage.googleapis.com/1a/e2/6b/717b679835010a/US4921417.pdf · https://patents.google.com/patent/US4276015 (citing reference)

I'll search for litigation involving US patent 4921417.

Let me run more targeted searches on litigation databases.

Let me try a few more targeted searches to confirm the absence of litigation.

Litigation Search: US Patent 4,921,417

Bottom Line

No litigation involving US Patent 4,921,417 was found. I searched litigation-focused sources (Unified Patents litigation portal, CourtListener/RECAP, and general web searches keyed to the exact number) and could not identify any federal district court case, ITC Section 337 investigation, or CAFC appeal in which the '417 patent was asserted or challenged.

Why This Result Is Consistent With the Patent's Profile

The '417 patent has characteristics that make litigation unlikely to be findable or to exist at all:

An expired 1990 mechanical patent in a small commercial field, held by a small entity, is not the kind of asset that typically generates recorded infringement litigation.

Important Caveat on Negative Results

I must be explicit about the limits of this conclusion:

• My searches did not return any authoritative litigation-database hit for this specific number. They also returned a large volume of false positives for the bare string "4921417," including a Russian patent application number (SU 4921417/27), a CourtListener financial-disclosure investment ID, and a trademark registration number — none of which relate to the U.S. patent.
• A truly exhaustive check would require direct queries of PACER, Docket Navigator, Lex Machina, or the Unified Patents litigation caselist filtered to patent number 4,921,417, and possibly a Westlaw/LexisKeyCite litigation history report. I cannot claim to have executed those database-native queries; I only performed general web searches.
• Because the patent expired in 2007, any past litigation would be at least ~19 years old and may not be well-indexed in free sources.

Suggested Verification Steps

If you need a definitive, citable negative or a complete history:

1. Unified Patents litigation portal – search the patent number directly in the caselist: https://portal.unifiedpatents.com/litigation/caselist
2. CourtListener / RECAP – run a docket search for "4,921,417" or "4921417" (party name "Sato Manufacturing").
3. PACER – Case Locator by party name "Sato Manufacturing Co."
4. Lex Machina / Docket Navigator – patent-number litigation report (most reliable for a certified negative).
5. USPTO Patent Center / Assignment records – to check for any recorded assignments that might hint at enforcement activity.

Conclusion: Based on the searches performed, there is no known litigation involving US Patent 4,921,417. I state this as a negative search result rather than a certified absence, and I flag the database limitations above so the conclusion is not overstated. Note also that I did not auto-correct the number — all results keyed to the literal "4921417" string that concerned unrelated registrations were excluded.

Proceedings overview

Total AIA trial proceedings on file for US 4,921,417: 0. No IPRs, no PGRs, no CBM reviews — so there is nothing to break down by "claims invalidated / claims sustained / settled / institution denied," and the defensive posture is not "hardened by surviving IPRs" (the patent never faced one) but rather "unreachable by AIA trial and long expired": the structured USPTO Open Data Portal block reports no AIA trial proceedings as of the most recent ingest, and my independent searches of PTAB materials surfaced no petition, institution decision, Final Written Decision, or appeal naming this patent. The patent expired years before the AIA's IPR provisions even took effect on 2012-09-16, so no economically rational petitioner ever had a reason to file.

No proceedings to enumerate

Because the count is zero, the per-proceeding template does not apply. What I can report instead:

• Type: N/A — no Inter Partes Review, Post-Grant Review, or Covered Business Method review identified.
• Filed: N/A.
• Status: N/A (no proceeding to gloss).
• Judge panel: None. No APJ panel has ever been assigned to this patent.
• Petition grounds: None of record.
• Institution decision: None of record.
• Final Written Decision: None. No claim of US 4,921,417 has ever been adjudicated by the Board. Claim 1 is the patent's only claim, and it remains UNTESTED at the PTAB.
• Settlement / termination: N/A.
• Appeal: No Federal Circuit appeal from any PTAB decision concerning this patent — there is no such decision to appeal. (A Federal Circuit appeal can only follow a Board decision, so its absence is confirmatory, not independent evidence.)
• Defensive value: Because there is no IPR record, a defendant gets no § 315(e)(2) estoppel shield for free, but also inherits no adverse FWD. The real defensive asset here is not an IPR — it is the patent's expiry, discussed below.

Verification performed / number-collision warning

I searched for AIA-trial material keyed to this patent and hit only false positives worth flagging so you don't propagate them into a brief:

• 4921417 is also a Soviet/Russian application number on RU 2,011,902 C1 (a motor-axle bearing patent, filed 1991-01-09, published 1994-04-30) — see RU2011902C1. Unrelated art, unrelated patent system.
• 4921417 appears as a CourtListener investment-record ID in a Judicial Financial Disclosure API entry — an internal database key, not a patent.
• p-4921417 is a Fisher Scientific catalog code for a protease — not a patent.
• IPR2016-01895 concerns U.S. Patent 7,697,492 (a "…'492 patent"), not 4,921,417. Only the last three digits collide. Cite it in a brief and you will be embarrassed.
• The '417 is cited as prior art by later patents (e.g., US 7,393,449, Marathon Ashland Petroleum LLC), and its own cited-by list on Google Patents is limited to unrelated records (ES2144935A1, US 2004/0094454 A1, USD750728S1). Being cited by other patents is not a proceeding against it.

Links I checked: the Google Patents record for US4921417A (Authoritative source in this prompt, showing "Expired – Lifetime" and no PTAB links beyond the citation tables), and Justia's parallel copy. If you need a belt-and-suspenders docket check, run the patent number through USPTO PTAB E2E and the USPTO PatentCenter "Proceedings" tab — but nothing in the public record I searched suggests either will return a hit.

Strategic summary

Claim status: claim 1 (the sole claim) is neither canceled nor sustained — it is simply untested, and now unenforceable-by-expiry. US 4,921,417 issued 1990-05-01 from application 07/287,541 (filed 1988-12-19, as a divisional of abandoned Ser. No. 104,259 filed 1987-10-05, priority 1987-10-05). It is a pre-AIA patent. Google Patents lists an "anticipated expiration" of 2007-10-05, which I take at face value but flag as anomalous — that date coincides with the priority date rather than either conventional terminal date. The defensible endpoints for a pre-URAA patent are 17 years from grant (2007-05-01) or 20 years from filing (2008-12-19); on any of those three dates the patent was dead by the end of 2008. The AIA's IPR regime did not exist until 2012-09-16, roughly four to five years after expiry. That single fact explains the empty docket better than any litigation-strategy story: there was no live monopoly to attack.

Estoppel landscape: no § 315(e)(2) estoppel exists, because no petitioner ever triggered it — but nothing is lost by that. With no IPR, no petitioner or privy is statutorily barred from raising prior-art or § 112 grounds in district court or the ITC; conversely, you have no FWD to point to that canceled anything. Your invalidity toolkit is therefore the full, mundane one: §§ 102/103 on patents and printed publications, plus §§ 101/112 defenses that are unavailable in an IPR anyway. Note that the eight references cited on the face of the patent (US 571,958; US 3,125,780; US 3,469,411 to Olin Mathieson; US 3,788,790 to Niitm Pri Ban; US 4,276,015 to Rogers, "Method and apparatus for molding clay pigeons and the like"; US 4,623,150 to Reagent Chemical; and JP 61-162538 and JP 63-317399) were all considered by the examiner — prosecution-history estoppel/§ 325(d) considerations that would have made an IPR on those references harder are moot here, and they remain fair game as art. Rogers in particular is the most on-point pre-issuance art for a "blow a sand-and-binder mix into a clay-pigeon mold" apparatus.

Pattern signals: none of the usual ones. There is no repeat petitioner (there is no petitioner at all), no PTAB appeal activity by Sato Manufacturing Co. Ltd. or any successor, and no defensive aggregator — no Unified Patents, RPX, or similar entity — in the chain. CBM review was categorically unavailable (this is a sand-molding apparatus, not a "covered business method" patent), and PGR was unavailable because the patent predates first-inventor-to-file (the only AIA trial type that could have reached §§ 101/112 was PGR, and pre-AIA patents are excluded from it). This is a quiet, single-claim, 1980s-era mechanical patent that aged out without ever being contested at the Board.

Recommended next steps

• If you have received a demand letter or complaint citing US 4,921,417, check the number itself before doing anything else. A patent that expired by 2008-12-19 at the outside cannot support an injunction, an ongoing royalty, or post-expiry damages for pre-expiry conduct you did not commit. If the number in the letter is right, the letter is very likely a citation error or a copy-paste from a prior-art table (the '417 shows up as prior art in later patents, which is a common way for its number to land in the wrong document). Verify against the Google Patents record and the Justia copy.
• If the number is wrong and a different patent is at issue, treat the numbers as distinct and re-run this analysis on the correct patent — do not assume the '417 analysis transfers. Confirm the correct patent's PTAB history via USPTO PatentCenter (Proceedings tab) and PTAB E2E, and its litigation history via CourtListener RECAP dockets.
• If the assertion is genuinely about the '417, your posture is simple and strong: (1) plead expiration and laches/§ 286 damages-bar as applicable; (2) if any pre-expiry conduct is alleged, maintain contemporaneous invalidity contentions under §§ 102/103/112 using the face-of-patent art — you are unconstrained by any IPR estoppel; and (3) note that IPR is not a useful tool here: the Board will institute on expired patents in theory, but with no possibility of injunctive relief and no claim-amendment runway, an IPR would be an expensive nullity for a defendant who has a straightforward expiry defense.
• Do not represent to a court or client that "the PTAB canceled claims" or "the patent survived IPRs." Neither happened. The accurate statement is: No AIA trial proceeding has ever been filed against US 4,921,417, and claim 1 has never been construed or adjudicated by the Board.

I'll verify the assignment record before reconstructing the chain.

Let me check for any post-issuance transfers, litigation, or entity-status records.

Let me check for sibling patents in the family and the assignee entity's status.

Ownership & Assignment Analysis — US 4,921,417

Patent: Molding apparatus for molding a clay pigeon
Application: US 07/287,541 (divisional of Ser. No. 104,259, filed 1987-10-05, now abandoned)
Filed: 1988-12-19 · Issued: 1990-05-01 · Anticipated expiration: 2007-10-05
Status: Expired – Lifetime

Methodology note / limitation. I could not execute a live query against the USPTO Assignment Center API in this session. The findings below rest on (a) the Google Patents legal-events record, which mirrors USPTO reassignment data, and (b) web searches for litigation, assignment, and NPE-directory hits. Where that distinction matters, I flag it rather than assert it.

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Inventors

• No unusual departures detectable. With a single inventor, the "all inventors exit within 12 months" fire-sale tell cannot apply in the usual multi-inventor form, and there is no inventor-to-inventor assignment trail (no AS-type legal events of any kind).
• The inventor surname (Sato) matches the assignee's corporate name, the classic inventor-founded operating company pattern — the opposite of an inventor assigning away to a stranger.

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Original assignee

Sato Manufacturing Co Ltd — named as both original and current assignee on the Google Patents record.

• Name variant flagged (not auto-corrected): Justia's assignee page for this same patent renders the owner as "Sato Factory Co., Ltd." Both are standard English renderings of a Japanese corporate name of the 佐藤製作所 Sato Seisakusho type. I cannot resolve from available records whether these are the same legal entity under two translation conventions or two distinct entities. Treat the assignee identity as Sato Manufacturing Co Ltd / Sato Factory Co., Ltd. pending a certified abstract of title.
• What they do: The patent itself establishes the line of business — the assignee designed and operated sand-based clay pigeon molding apparatus, i.e. a shooting-target manufacturer, not a patent-holding vehicle. The specification is written from the manufacturer's perspective throughout ("a preferable result was obtained by using a bypass tube 19 having an inner diameter of 7 mm for a molding apparatus provided with a duct 17 having an inner diameter of 30 mm as an example").
• Product embodying the claims: Yes, on the face of the record — the specification describes a production process with concrete operating parameters (mold heated to ~280 °C, 2–4 kg/cm² compressed air, 2–3 second supply, ~10 second sinter in-mold), which is the profile of a real production line, not a paper disclosure.
• Current status: not determinable with confidence. I found no bankruptcy filing, dissolution notice, acquisition, or SEC record (a Japanese private company would not file with the SEC). I explicitly checked and can exclude the "Sato Corporation" (Tokyo, founded 1940 by Yuji Sato; barcode/labeling and mechatronics, ~6,000 employees) that surfaces in name searches — that is a different company, not the assignee here. Do not conflate the two.
• The patent's own lifecycle is the strongest status evidence: maintenance fees were paid through the year-12 payment on 2001-10-15 and the patent ran to its full statutory term on 2007-10-05. An owner that pays three maintenance fees on a niche sporting-goods patent is maintaining a live commercial position.

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Assignment timeline

The USPTO assignment record for US 4,921,417 contains no post-issuance assignments.

The complete set of legal events on the Google Patents record is:

• No reel/frame numbers to report. There is no AS (assignment), no security agreement, no merger, no change-of-name, no license, no release, and no correction entry anywhere in the chain. No correspondent of record exists for this patent because no assignment was ever recorded against it.
• The "Applications Claiming Priority" and "Related Parent Applications" entries are not assignments. They reflect the Ser. No. 104,259 → 07/287,541 parent/divisional relationship, not a transfer of rights.
• Practical conclusion: the patent was filed by, issued to, maintained by, and expired with Sato Manufacturing Co Ltd as owner of record. There is no chain to reconstruct.

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Timeline diagram

timeline
    title Ownership of US 4921417
    1987 : Parent application filed by Sato
    1988 : Divisional filed 19 Dec
    1990 : Patent issued 1 May
    1993 : Maintenance fee year 4 paid
    1997 : Maintenance fee year 8 paid
    2001 : Maintenance fee year 12 paid
    2007 : Patent expired 5 Oct

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NPE / troll-pattern signals

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Verdict

Insufficient data — in substance, a never-asserted, single-owner, naturally expired operating-company patent.

There is no assignment record to reconstruct: the Google Patents legal-events tab for US 4,921,417 shows only a grant event (STCF, 1990-02-28) and three maintenance-fee payments (FPAY: 1993-11-01 year 4; 1997-09-25 year 8; 2001-10-15 year 12), with no AS-type reassignment entry at any point, and the patent reached its anticipated expiration on 2007-10-05 still in the name of Sato Manufacturing Co Ltd. That absence is itself the finding — it means the original assignee retained ownership to expiry. Signal 3 cannot be scored because there is no correspondent of record; signals 1, 2, 4, 5, 6, 7 and 8 are affirmatively not present. The only residual caveat is the unresolved "Sato Manufacturing Co Ltd" vs. "Sato Factory Co., Ltd." naming variant, which is a title-identity question, not an NPE question.

Verify at: USPTO Assignment Center (search patent number 4921417) · Google Patents legal events

I'll verify the cited references against live sources before mapping them to claim 1.

Let me verify the two remaining US citations and the two Japanese citations.

Prior-Art Analysis of the Cited References for US 4,921,417

Scope note. Per the task, I keyed every query to the literal string 4921417 and did not substitute similar numbers. The bibliographic frame and claim text come from the authoritative full text supplied with this task (Google Patents, https://patents.google.com/patent/US4921417/en). I then verified the eight face-of-patent citations against live patent sources. I was not able to execute a database-native query of USPTO Patent Center/PAIR in this session (tool limit reached), so the § 102 statements below rest on the citation record plus the reference texts I retrieved. Where a reference's substance could not be retrieved, I say so rather than fill the gap — consistent with the Operating Rules.

This section builds on the previously generated Patent summary (claim 1 element breakdown), Litigation summary / PTAB (no proceedings; expired 2007), Assignment history, and Obviousness sections, and does not repeat them.

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0. The claim structure that governs every § 102 question here

US 4,921,417 has exactly one claim — claim 1 — and no dependent claims. That makes § 102 binary: either a single reference discloses every element of claim 1 arranged as claimed, or it does not anticipate. There is no intermediate claim scope to fall back on.

The elements that must all appear in one reference for anticipation are:

Because element (e)+(f) is a structural-and-functional combination unique in the record, the single-reference anticipation question essentially reduces to whether any cited reference discloses an air-carrying tube seated inside the material-feed orifice. As shown below, none does.

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1. The eight citations, with verified full data

The "Citations (8)" table on the face of US 4,921,417 lists the following. Dates are reproduced literally from the record; where a search result refined the record, that is flagged.

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2. Governing law for the date analysis

The '417 is pre-AIA. Its effective filing date is that of parent Ser. No. 104,259, filed 1987-10-05 (the divisional 07/287,541 was filed 1988-12-19). The critical dates are therefore:

• § 102(b) one-year bar: printed publications / patented or public-use activity more than one year before the U.S. filing date → before 1986-10-05.
• § 102(a): knowledge or use by others, or patents/printed publications, before the applicant's date of invention.
• § 102(e): U.S. patents granted on applications filed before the applicant's date of invention. Pre-AIA § 102(e) reaches U.S. applications/patents only — not foreign (JP) national publications.

This date framework matters for two of the eight citations and is flagged where it bites.

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3. Reference-by-reference § 102 analysis

3.1 US 4,276,015 (Rogers) — no anticipation; the primary § 103 reference

Status: § 102(b) art (granted 1981-06-30, well before 1986-10-05).

Element mapping:

§ 102 conclusion: Rogers does not anticipate claim 1 — elements (a), (b), (e), (f) and (g) are absent in the reference as a whole. Rogers is nonetheless the most relevant single prior-art document of record, because it is same-field (clay pigeons), it expressly discloses a cavity "in the shape of a clay pigeon," and it puts a smaller-diameter elongate member inside the material delivery passage — the closest known structural analogue to claim element (e). This is § 103 material, not § 102.

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3.2 US 4,623,150 (Moehlman / Reagent Chemical) — no anticipation; material-element art only

Status: § 102(a)/(e) art, not § 102(b). Granted 1986-11-18, which is after the 1986-10-05 one-year-bar date computed from the 1987-10-05 priority date. It is available under pre-AIA § 102(a) (patented before the invention date) and § 102(e) (U.S. application filed 1982-06-18, i.e., before the earliest plausible invention date). It is not § 102(b) art. This is a point on which the previous Obviousness section treated it as ordinary prior art; the § 102(b) unavailability is worth noting.

Element mapping: this reference claims a composition/article and a compression-molding method, not a blow-molding apparatus with a tank, compressor, duct and bypass tube.

§ 102 conclusion: does not anticipate claim 1 — a single reference cannot anticipate an apparatus claim that it does not disclose as an apparatus. It is relevant only to the "at least sand and hardening agent" limitation, and only as § 103 material.

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3.3 US 3,469,411 (Olin Mathieson / Silva) — no anticipation

Status: § 102(b) art (1969-09-30).

§ 102 conclusion: does not anticipate. Its only pertinence is that molding a trap target in a die cavity was old — a § 103 context point, already used in the Obviousness section's Combination A.

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3.4 US 3,125,780 — no anticipation; low relevance

Status: § 102(b) art (1964-03-24).

Discloses an apparatus and method for molding thin-wall foamed plastic cups from prefoamed beads that are mechanically sized and charged into a molding cavity, then expanded by heat. It has a mold cavity and a charge-feed system, but:

• the charge is thermoplastic beads charged with a blowing agent (polystyrene/methylchloride/butane), not sand + hardening agent;
• filling is by expansion of the beads in the cavity, not by air-blow entrainment through a blow orifice;
• there is no bypass tube inside an orifice, no duct-to-tank-top compressor arrangement, and no regulating valves in a bypass line.

§ 102 conclusion: does not anticipate claim 1, or any element except the generic notion of a molding cavity fed with a divided/particulate charge. Its citation appears to be as general molding-apparatus background. Notably, its subject matter is closer to US 4,921,417's own material class (particulate charge + in-mold bonding) than to any other cited reference, which supports using it as a § 103 context reference, not a § 102 reference.

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3.5 US 3,788,790 (Balevsky et al. / Niitm Pri Ban) — no anticipation

Status: § 102(b) art (granted 1974-01-29).

This is the reference whose bibliographic data the search results refine, and I flag the discrepancy rather than reconcile it silently:

• The face-of-patent citation table shows the date 1971-02-20. The Google Patents record for US 3,788,790 shows: Appl. No. 227,882, filed Feb. 22, 1972; a foreign priority of Feb. 20, 1971 (Bulgaria 16865); granted Jan. 29, 1974; inventors Anguel Tonchev Balevsky, Ivan Dimov Nikolov, Dragan Iliev Nenov, Emil Nikolov Momchilov (Sofia, Bulgaria); assignee Niitm Pri Ban, Sofia, Bulgaria; 3 claims; U.S. Cl. 425/242, 164/119, 164/285; Int. Cl. B22d 27/14.
• So the "1971-02-20" on the face is the Bulgarian foreign priority date, not the U.S. filing date. The U.S. patent filing date is 1972-02-22. I have not auto-corrected the record; I report both literally.

Substance (correcting the "could not retrieve" flag in the prior Obviousness section — the specification is now retrieved): an apparatus for casting under pressure in which mold parts are connected to relatively telescoping chamber walls, at least one actuated by a fluid-responsive device (e.g., a hydraulic cylinder) to ensure tight closure of the mold against the counterpressure. The stated field is "casting high-volatility metals and other materials, e.g. synthetic resins, and substances which decompose at low pressures and at melting temperatures in a mold under counterpressure." It also cross-references commonly assigned US 3,532,154 and US 3,693,698 (casting utilizing fluid pressure differentials).

§ 102 conclusion: does not anticipate claim 1. It supports only the mature-art proposition that pressure-filling/closing a mold cavity is old, which is already conceded by the '417 specification itself ("molding apparatuses which utilize a mold and form the target by using pressure are known"). This is a § 103 background reference at best.

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3.6 US 571,958 — no anticipation; not retrievable

Status: § 102(b) art (1896-11-24 — the earliest reference of record).

I could not retrieve the specification text, and I will not characterize its disclosure beyond its title, "Flying target." A 19th-century "flying target" to that title is an article reference with no molding apparatus. On the face of the record it cannot disclose a tank, compressor, duct, blow orifice, bypass tube, or regulator.

§ 102 conclusion: does not anticipate claim 1. Its relevance — if any — is as evidence that frangible flying targets were ancient, which is atmospheric rather than probative. Explicit uncertainty flag: I have not read this reference.

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3.7 JP S61-162538 — no anticipation; apparent non-analogous reference

Status: printed publication 1986-07-23, i.e., before the 1986-10-05 one-year-bar date. It would therefore qualify as § 102(b) art if it were pertinent.

As rendered on the face of the record, the document is "Extensible sticky film composition of polyethylene base material" by BP Chemicals — a polymer-film composition. As literally recorded, it discloses nothing about clay pigeons, sand-and-binder molding, or blow-feeding apparatus.

§ 102 conclusion: does not anticipate any element of claim 1. I flag it as an apparent record anomaly (see § 8) rather than guessing what the intended citation was.

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3.8 JP S63-317399 — no anticipation; AND not prior art on its face

Status: publication 1988-12-26. This date post-dates both the '417's U.S. filing date (1988-12-19) and its priority date (1987-10-05). As rendered, the document is "Underlay for calligraphy" by Ido Mitsuhiro (filed 1987-06-19).

Two independent grounds for exclusion:

1. Subject matter: on its face unrelated to clay pigeons or molding apparatus — no element of claim 1 is disclosed.
2. Date/statutory status: a Japanese national publication dated after the U.S. filing date is not § 102(a) or § 102(b) art, and pre-AIA § 102(e) does not reach foreign national publications. On the record as it stands, this reference is not available as prior art against claim 1 at all.

§ 102 conclusion: does not anticipate, and should not be relied on as § 103 art either. Flagged as a record anomaly (§ 8).

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4. Consolidated § 102 verdict table

Only claim 1 exists, so "potentially anticipates" is answered for claim 1 only.

No reference of record anticipates claim 1 under 35 U.S.C. § 102. The closest is US 4,276,015, and it fails on at least five elements. The anticipatory gap in the cited set is the same gap identified in the prior Obviousness section: element (e)/(f), the air-carrying bypass tube seated in the blow orifice.

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5. Cross-reference and one correction to the earlier Obviousness section

The previously generated Obviousness section concluded claim 1 is vulnerable under § 103 via Rogers + US 4,623,150 + the core-blower art (US 2,820,998; US 3,540,520; EP 0 158 082) + GB 1,463,360. This § 102 analysis is consistent with it and sharpens two points:

1. Correction: US 3,788,790 is now retrievable in substance (see § 3.5). It is a counterpressure/die-casting machine with telescoping chamber walls closed by a hydraulic cylinder — i.e., it corroborates only the "pressure-driven mold filling is mature art" proposition, and it contains no air-in-the-material-path teaching at all. The earlier section listed it as a low-confidence alternative (Combination B) precisely because its text was unavailable; with the text now available, Combination B is weaker, not stronger, and should not be relied on.
2. Refinement: US 4,623,150 is § 102(a)/(e) art, not § 102(b) art, given its 1986-11-18 grant versus the 1986-10-05 one-year-bar date. This does not impair it as § 103 art, but any pleading should use the correct statutory subsection.

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6. Most relevant prior art, ranked

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7. Best "anticipation" case that could be argued — and why it fails

The only colorable § 102 argument from the cited set is from Rogers alone, on the theory that pin 28's placement "in" passage 23 with a diameter "considerably smaller" than the passage reads on element (e). It fails on four independent grounds:

1. Pin 28 is not a tube. It is a solid, internally heated metal pin whose function is to plug and unplug opening 41a by reciprocation — the opposite of conveying compressed air.
2. No air is conveyed through it. Claim element (f) requires that "a part of the compressed air from said compressor pass[] through said bypass tube to lead blowing of the molding material." Rogers has no compressor-driven air in the material path.
3. No "duct" for the rear end. Element (e) requires the rear end "disposed in the duct in parallel with said duct." Rogers has no duct connected to an upper portion of a material tank.
4. No tank of sand + hardening agent, and no regulating valves. Elements (a) and (g) are wholly absent.

Under Verdegaal Bros. v. Union Oil Co., 814 F.2d 628 (Fed. Cir. 1987), a single reference must disclose every element arranged as in the claim; Rogers does not.

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8. Uncertainty flags and record anomalies (required)

1. JP S63-317399 is not prior art by date AND appears non-analogous. Its publication date (1988-12-26) post-dates the '417's U.S. filing date (1988-12-19) and priority date (1987-10-05), and a Japanese national publication is not pre-AIA § 102(e) art. Its rendered subject matter ("Underlay for calligraphy," Ido Mitsuhiro) is unrelated to clay pigeons. I have not auto-corrected this identifier.
2. JP S61-162538 likewise appears non-analogous. Rendered as a BP Chemicals polyethylene film composition, with no apparent relationship to molding apparatus or sand/binder targets. I have not auto-corrected this identifier.
3. US 3,788,790 date discrepancy. The face-of-patent table shows "1971-02-20" (the Bulgarian foreign priority date). The actual U.S. filing date is 1972-02-22; grant 1974-01-29. Reported literally both ways, per the Operating Rules.
4. US 571,958 was not retrieved. I have not read it and cannot state its disclosure beyond its title.
5. JP S61-162538 and JP S63-317399 were not retrieved. The tool limit was reached before I could verify their texts. Everything I say about them derives from the face-of-patent rendering.
6. No database-native USPTO query executed. I could not complete a live Patent Center/PAIR or PTAB E2E query in this session; the citation set is taken from the authoritative full text supplied with the task.
7. Date inconsistency in the task wrapper (carried forward). The system prompt states today's date as 2026-09-29 while the task text states "Current Date: April 26, 2026." The prior sections flagged this same contradiction. It does not affect the pre-AIA § 102/§ 103 analysis, but I note it rather than silently choosing one.
8. Statutory posture. Per the prior Litigation and PTAB sections, US 4,921,417 expired (anticipated expiration 2007-10-05) with no litigation or AIA proceeding of record. This is therefore a retrospective validity assessment, not a prediction of a live proceeding.

Key URLs: https://patents.google.com/patent/US4921417/en · https://patents.google.com/patent/[US4276015A](/patent/US4276015A)/en · https://www.freepatentsonline.com/[4276015](/patent/4276015).html · https://patents.google.com/patent/US4623150 · https://patents.justia.com/patent/[4623150](/patent/4623150) · https://patentimages.storage.googleapis.com/94/38/70/8825b93d0f48a7/WO2001042731A1.pdf · https://patents.google.com/patent/US3469411 · https://patents.google.com/patent/[US3788790A](/patent/US3788790A)/ · https://patents.google.com/patent/US3125780

I'll research the cited prior-art references to ground the obviousness analysis.

Let me dig into the remaining cited references and the foundry blow-tube art.

Obviousness Analysis — US 4,921,417 under 35 U.S.C. § 103

Builds on the previously generated "Patent summary" and "Litigation summary." This section assumes the claim-1 construction already set out there (single independent apparatus claim; "and/or" in the last element) and does not repeat the bibliographic or litigation work.

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1. Framework and the person of ordinary skill

The application was filed 1988-12-19 (priority 1987-10-05), so pre-AIA § 103 governs, with the Graham v. John Deere Co., 383 U.S. 1 (1966) factors. The KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) reasoning on "predictable results," "obvious to try," and "design incentives" is still the operative articulation for the PHOSITA inquiry.

Level of ordinary skill. The claimed subject matter is elementary mechanical/pneumatic equipment: a hopper, a compressor, a hose/duct, a two-part mold, a nozzle/orifice, a small tube, and an air-line valve. A PHOSITA would be a mechanical engineer or tooling designer with a bachelor's degree and roughly 2–3 years' experience with sand-core/blow molding equipment and shop-pneumatics, or a skilled machine designer of equivalent experience. Notably, the specification itself uses the term "core sand … for molding a core" and a phenol-aldehyde thermosetting resin, i.e., the claim's "sand and hardening agent" is the standard foundry core-sand system. That fact anchors the relevant analogous art in the foundry core-blowing ("coreshooter") field, not just in clay-target manufacturing. Every element in claim 1 is a conventional, low-complexity mechanical/pneumatic item, which lowers the bar for "predictable" combinations.

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2. What the prior art of record actually teaches

I verified content where the sources permitted; where I could not, I say so rather than fill the gap.

Supplementary analogous art (located in my searches but not among the "Citations" on the face; used only to show what the sand-blowing field already knew):

• US 2,820,998 — a machine for forming shell molds from a mixture of sand and particulate thermosetting material; a "blow head" forces the mixture by air blast into the pattern cavity, and claim 5 recites "a flexible spreader valve secured within the sand tube adjacent the bottom thereof to cause the air blast to spread out to the interior surface of the tube to prevent the blast being confined to the center of the tube." This is a structural member placed inside the material-blowing conduit purely to manage the air blast (PDF).
• US 3,540,520 (issued c. 1970) — a core/mold blow reservoir with a blow plate having blow apertures "through which sand will be blown into the mold or core box"; a screen and tangential airflow "have been found to enhance air flow and provide more efficient fluidization and packing of the sand into the mold or core box" (PDF). This is motivation evidence: manipulating how air is introduced into the sand path to improve packing of sand into a mold was a known, written-about objective.
• EP 0 158 082 A2 (pub. 1985-10-16) — a "bottom-blow" blow box in which air is supplied to a peripheral gap/slot so that "the initial flow of air directed toward the exit tends to sweep … pre-settled sand through the exit" (PDF). Again: directing air in the sand path to drive material through the outlet was known.
• GB 1,463,360 (1977), "Abrading guns" (listed under Google's Similar Documents) — the classic sand-blast/eductor principle: a compressed-air jet through a nozzle draws and entrains particulate abrasive. This is the closest generic analogue to the claim's stated function "to lead the blowing of the molding material."
• ⚠️ EP 0 480 164 A1 (blow tube with transverse exit openings inserted into a cavity entrance bore) surfaced in my searches but published in 1992, i.e., after the '417 filing date. It is not available as prior art here and I expressly exclude it from the combinations below.

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3. Combination A (strongest): Rogers '015 + US 4,623,150 + the sand-blow architecture and air-management teachings of the core-blowing art

Element-by-element mapping

Motivation to combine (the KSR-required articulated reasoning)

1. Same problem, same field. The '417 specification concedes the problem verbatim: "in the prior art devices, it is difficult to cause sand to permeate into the corners and details of the mold … a problem in molding a clay pigeon of high quality due to poor filling of the mold with sand." Rogers is in the clay-pigeon field and addresses filling/quality of the molded pigeon (its stated objects include avoiding sprues, flashing and imperfections, and easy release). A PHOSIT seeking to improve fill of a clay-pigeon cavity would begin with Rogers.
2. Same materials and same physical technique. Rogers contemplates "chinaware and other types of ceramics or plastic materials"; the '417 charge is foundry core sand + thermosetting resin. Because the material system is the foundry core-sand system, the core-blowing art (US 2,820,998; US 3,540,520; EP 0 158 082) is reasonably pertinent art — it addresses the identical problem (getting a sand/binder mixture to fill the extremities of a mold) by the identical mechanism (air-blown sand).
3. The art already taught that how you introduce the air into the sand path controls fill quality. US 3,540,520 states the air-flow arrangement "enhance[s] air flow and provide[s] more efficient fluidization and packing of the sand into the mold"; EP 0 158 082 relies on air flow "toward the exit" to sweep and drive sand out. A PHOSIT designing a machine that under-fills would therefore be led, not taught away, to add an auxiliary air jet in the blow orifice to "lead" (entrain) the sand — exactly the claim's stated function.
4. Predictable result, finite solution set. Adding a smaller-diameter air tube into a nozzle/orifice to entrain a particulate stream is the textbook eductor/air-blast principle (GB 1,463,360). Using a standard pressure/flow regulator to trim that auxiliary air is routine tuning. KSR: "the combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results."
5. No teaching away in Rogers. Rogers' pin is deliberately sized smaller than the passage so material flows freely around it, and it is retracted during filling (FIG. 3). Nothing in Rogers discourages placing an element inside the feed passage; if anything, Rogers legitimizes routing auxiliary hardware (heaters, actuating rods) into and through the material passage.

Conclusion on Combination A: Claim 1 would have been obvious to a PHOSITA. The only element not expressly shown (the air-carrying bypass tube inside the orifice) is the predictable application of a known fluid-entrainment/air-management technique to a known clay-pigeon mold in which the same class of sand mixture was already blown under air pressure.

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4. Alternative combinations (cumulative/backup theories)

Combination B — Rogers '015 + US 3,788,790 + routine skill.
Rogers supplies the clay-pigeon cavity and the feed passage with a smaller-diameter member inside it; US 3,788,790 (if, as its title indicates, it discloses pressure-forcing of material into a mold) supplies pressure-driven mold filling. Difference: air-assist. Motivation: the admitted short-fill problem. Caveat: I could not verify US 3,788,790's substance, so this theory is weaker and should be corroborated before being relied on.

Combination C — "single reference + admitted prior art + routine skill" (KSR "obvious to try").
Take Rogers '015 as the whole apparatus context, add the admitted background ("molding apparatuses which utilize a mold and form the target by using pressure are known"), and add the ordinary artisan's knowledge that (a) air-through-a-smaller-tube entrains particulate and (b) air-line regulators are standard. The remaining differences reduce to a design choice in tube diameter, tube routing (rear end in the duct, front end in the orifice), and valve placement, none of which produce an unexpected result.

Combination D — Rogers '015 + US 4,623,150 for the material limitation.
Wholly conventional: selecting a sand/filler + resin binder charge for a molded frangible target is taught by US 4,623,150, and the "at least sand and hardening agent" limitation adds no inventive weight.

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5. Objective indicia (secondary considerations)

No evidence of record supports nonobviousness. The specification asserts improved corner/detail filling and easier painting, but:

• These are the expected results of the asserted (known) technique, not "unexpected results" relative to the closest art (US 3,540,520 and EP 0 158 082 already tout improved "packing of the sand" and driving sand "through the exit" via air management).
• There is no evidence of commercial success, long-felt need, failure of others, copying, or industry praise, and no nexus evidence tying any such fact to the claimed bypass tube. The patent's own framing ("can be implemented by the addition of a tube member to a basic configuration of an existing molding apparatus, which can be done inexpensively") affirmatively characterizes the advance as a cost-driven, routine retrofit — the classic KSR "design incentive / market force" situation.
• The single-claim scope with "and/or" further narrows the gap: a prior-art suggestion of either a pressure regulator or a flow regulator is sufficient.

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6. The best nonobviousness counterarguments (and my assessment)

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7. Bottom line

Claim 1 of US 4,921,417 is, in my assessment, vulnerable to a § 103 rejection — moderately strong to strong — based on the combination of Rogers (US 4,276,015) as the clay-pigeon-molding primary reference, the standard sand-blow machine architecture and air-management teachings of the core-blowing art (e.g., US 2,820,998; US 3,540,520; EP 0 158 082), the material limitation taught by US 4,623,150, and routine pneumatic design for the regulators.

The single claim's breadth (one independent claim; no dependent claims narrowing tube diameter, tube length, orifice geometry, pressure ranges, or control logic; and the disjunctive "and/or" valve requirement) materially reduces the nonobviousness argument. The patent's asserted advantage — better filling of fine mold detail — is precisely the result the sand-blowing art was already documented as pursuing by manipulating how air is introduced into the sand path. Under KSR, adding a small air tube through a nozzle/orifice to entrain particulate (the eductor principle) and trimming it with a standard regulator is the kind of predictable, finite-solution variation that is obvious as a matter of law.

Where I would hedge for litigation-grade certainty: a genuinely exhaustive § 103 opinion would need (i) the full text of the uncited analogous references cited above and of US 3,788,790, and (ii) confirmation whether any additional sand-blow air-assist art (e.g., coreshooter "venturi/sleeve" heads) predates 1987, because that art would move the case from "obvious combination" to nearly inescapable.

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8. Uncertainty flags and contradictions (as required by the operating rules)

1. Mislabeled / possibly non-analogous cited Japanese references (and one date problem). The record lists JP S61-162538 as "Extensible sticky film composition of polyethylene base material" (BP Chemicals) and JP S63-317399 as "Underlay for calligraphy" (Ido Mitsuhiro). Taken literally, neither relates to clay pigeons or molding apparatus, so neither contributes to the § 103 case. Worse, JP S63-317399's publication date (1988-12-26) post-dates the US filing date (1988-12-19) and the 1987-10-05 priority, so on the face of the record it would not even qualify as § 102(a)/(b) art (a foreign published application is not § 102(e) art in the pre-AIA regime). I have not auto-corrected these identifiers; I flag them as apparent record anomalies rather than substituting what the "real" citations might be.
2. Unverified references. I could not retrieve the specifications of US 3,788,790 or US 571,958, nor confirm JP S61-162538 / JP S63-317399 substantively. Anything I attribute to US 3,788,790 is inference from its title and should not be relied on.
3. Supplementary art is not "of record." US 2,820,998, US 3,540,520, EP 0 158 082 and GB 1,463,360 appeared in my searches as analogous art and/or Google's Similar Documents list; they are not among the eight "Citations" on the face of US 4,921,417 that the task instructed me to use. My primary combination therefore rests on the cited set (Rogers + US 4,623,150), with the core-blower references supplying the motivation evidence. If the analysis must be confined strictly to the eight cited references, the § 103 case becomes weaker but not defeated (Combination B/C), because Rogers alone places a smaller-diameter member inside the feed passage and the specification concedes the pressure-molding apparatus.
4. Excluded reference. EP 0 480 164 (blow tube with transverse exit openings) was retrieved but post-dates the '417; I deliberately did not use it. Anyone reusing this analysis should keep that exclusion.
5. Date inconsistency in the task wrapper. The system prompt states today's date as 2026-09-27 while the task text states "Current Date: April 26, 2026." This does not affect the § 103 analysis (pre-AIA law applies regardless), but I am flagging the contradiction as instructed rather than silently choosing one.
6. Statutory posture. The '417 is expired (anticipated expiration 2007-10-05) and, per the prior section, no litigation/PTAB challenge was located. This analysis is therefore a retrospective validity assessment, not a prediction of any live proceeding.

Key URLs used: https://patents.google.com/patent/[US4276015A](/patent/US4276015A)/en · https://www.freepatentsonline.com/[4276015](/patent/4276015).html · https://patents.google.com/patent/US4623150 · https://patentimages.storage.googleapis.com/94/38/70/8825b93d0f48a7/WO2001042731A1.pdf (search report identifying US 4,623,150 as target binder/filler chemistry) · https://patentimages.storage.googleapis.com/86/08/94/9239f70cf14616/US2820998.pdf · https://patentimages.storage.googleapis.com/69/6f/e0/b8893032af29f7/US3540520.pdf · http://data.epo.org/publication-server/rest/v1.0/publication-dates/19851016/patents/EP0158082NWA2/document.pdf · https://patents.google.com/patent/US4921417/en