US 6148976

I'll search for this specific patent number across the requested sources.

Now let me check for any litigation or CAFC docket activity and USPTO status records.

US Patent 6,148,976 — Analyst Summary

Search note: I ran targeted queries against the patent record and open web/patent databases, but I did not obtain any results from a USPTO-internal database or a CAFC 2026 docket system. No CAFC 2026 docket entry, appeal, or litigation involving patent 6,148,976 surfaced in any search. I cannot confirm whether one exists; treat the absence of litigation findings as "not found," not as "confirmed none." The summary below is grounded in the authoritative full patent text provided.

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Bibliographic Data (authoritative, per record)

Prior art cited on the face of the patent: US 4,644,819 (Leggett & Platt, "High-low speed drive system for multiple spindle machines"); US 5,657,843 (Midwest Brake Bond, "Press drive with oil shear clutch/brake drives"); US 5,730,037 (Logan Clutch, "Multi-spindle machine control systems" — incorporated by reference). The application also cross-references U.S. App. Ser. No. 08/871,019 ("Multi-Spindle Machine Retrofit System," later US 6,050,162).

Forward citations: US 6,848,347 B1 (Logan Clutch, "Multi-spindle machine") and US 7,225,909 B1 (Logan Clutch, "PTO clutch assembly").

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Abstract (as issued)

A clutch arrangement for a multi-spindle machine includes a starting clutch 12 and a machine brake clutch 14 positioned on a starting clutch drive shaft 16. A high speed clutch 18 and a snubbing clutch 22 are positioned on a long worm drive shaft 20. All clutches are pneumatically operated by solenoid valves 40, 42, 44 and 46 and electrically actuated by electrical circuit 60. When the multi-spindle machine shifts from a high speed to a low speed, the invention activates the machine brake clutch 14 and snubbing clutch 22 for a predetermined time period to cause the drive train gears to slow down, allowing synchronous meshing with the low speed drive train and reducing machine cycle time.

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Plain-Language Overview of the Independent Claims

There are four independent claims — three apparatus claims (1, 15) and one method claim (13). Claims 1 and 15 are near-duplicates; claim 15 is drafted in "adapted to be positioned" language (a retro-fit-oriented form).

Claim 1 — Clutch arrangement (mounted form)

A clutch arrangement for a multiple-spindle machine that runs at either low or high speed and has a timing shaft. Four elements:

1. Starting clutch — surrounds the starting clutch drive shaft; when engaged, the machine runs at low speed.
2. Machine brake clutch — also surrounds the starting clutch drive shaft, spaced lengthwise from the starting clutch; when the starting clutch is disengaged, it can be engaged to slow the starting clutch drive shaft.
3. High speed clutch — surrounds the long worm drive shaft and is in selective operable connection with the starting clutch drive shaft; when engaged, the machine runs at high speed.
4. Snubbing clutch — also on the long worm drive shaft, spaced lengthwise from the high speed clutch; when the high speed clutch is disengaged, it can be engaged to slow the long worm drive shaft rotation.

The point: the brake clutch and snubbing clutch actively decelerate the drivetrain so the machine can drop from high to low speed quickly instead of coasting down on inertia.

Claim 13 — Method of operating the machine

The method counterpart of Claim 1, covering the same four clutches on the same two shafts. Steps: selectively operate the starting clutch to rotate the starting clutch drive shaft (low speed when engaged); selectively operate the machine brake clutch to slow that shaft when the starting clutch is disengaged; selectively operate the high speed clutch (selectively connected to the starting clutch drive shaft) to rotate the long worm drive shaft (high speed when engaged); and selectively operate the snubbing clutch to slow the long worm drive shaft when the high speed clutch is disengaged.

Claim 15 — Clutch arrangement (retro-fit / "adapted to be positioned" form)

Functionally identical to Claim 1, but each clutch is recited as "adapted to be positioned in generally surrounding relation with" the respective shaft. This is the retrofit claim format, consistent with the specification's statement that the system is "particularly suited for retrofitting a multi-spindle machine, but also is suited for incorporation in a newly manufactured multiple spindle machine." The specification specifically names the Davenport Model B five-spindle automatic screw machine as the preferred host machine.

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Key Dependent Claim Themes (for context)

• Pneumatic actuation (claims 2, 16) with one solenoid valve per clutch (claims 3, 17).
• Electrical control circuit (claims 4, 18) optionally microprocessor-controlled (claims 5, 19).
• Timing shaft limit switches + timer (claims 6, 20): a first limit switch triggers a timer that energizes the snubbing-clutch solenoid for a set period; a second limit switch energizes the high speed clutch solenoid.
• Encoder alternative (claims 7, 21): an absolute ten-bit Gray code encoder reports timing shaft position/velocity to the microprocessor, which handles snubbing/high-speed energization. (Specification cites Omron D4CC2024 limit switch and Omron H3CA solid-state timer as preferred components; encoder/controller details cross-referenced to US 5,730,037.)
• Multi-disc friction clutches (claim 8); adjustable torque capacity responsive to variable pressure (claims 9–10, 22).
• Stationary mounting brackets perpendicular to the shaft axes for the brake clutch (claim 11) and snubbing clutch (claim 12).

Preferred embodiment torque data (specification, not claim limitations): Starting/feed clutch — 8-disc, ~462 ft-lb at 80 psi; machine brake clutch — 6-disc, ~245 ft-lb at 80 psi; high speed clutch — 6-disc, torque curve "substantially identical" to the brake clutch; snubbing clutch — 2-disc, ~8 ft-lb at 40 psi rising to ~47 ft-lb at 70 psi.

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Uncertainty / Caveats

• No CAFC 2026 docket results were found. I could not verify any 2026 Federal Circuit activity for this patent. This may reflect genuinely no such docket, or a limitation in the search tools available to me. I am flagging this explicitly rather than asserting no litigation exists.
• USPTO "database" access: My results came from the patent text itself plus third-party patent aggregators (Google Patents, Justia, EveryPatent) and the assignee's own website — not a direct USPTO PatentCenter/Assignment query.
• The legal status "Expired – Lifetime" with an anticipated expiration of 2019-06-03 is as listed on the patent record; I did not independently verify maintenance-fee payment history or any terminal disclaimer/reissue/reexamination.
• Note a distinct, unrelated JP patent also numbered 6148976 (JP 6148976 B2, Mimaki Engineering, media cutting method) appeared in search results. It has no relationship to this US patent; I mention it only so the number is not conflated.

I'll research litigation involving US Patent 6148976.

Those hits are for an unrelated Japanese patent (JP6148976B2). Let me search litigation-specific sources for the US patent.

Litigation Search: US Patent 6,148,976

Bottom line: I found no evidence of any litigation involving US Patent 6,148,976. Based on the searches I was able to run, there do not appear to be any known infringement suits, declaratory-judgment actions, or PTAB/Court of Appeals proceedings asserting or challenging this patent.

I want to be explicit and honest about what these results do and do not establish, since you asked specifically not to auto-correct or substitute similar numbers, and not to invent case details.

What the search returned

No litigation-specific sources (Unified Patents litigation caselist, PACER, CAFC dockets, or news coverage) surfaced any case naming US 6,148,976. The relevant hits were all prosecution/ownership records, not court records:

Important false positive to flag: Searches for the bare digits "6148976" repeatedly returned JP6148976B2, a Japanese patent (No. 6148976) owned by Mimaki Engineering (株) for a "境界決定方法およびメディア切断方法" (boundary-determination / media-cutting method). That is an unrelated, different patent in a different jurisdiction and technology, and I am not treating it as US 6,148,976. You instructed me not to return results for similar numbers, so I'm calling it out only to explain the noise.

Procedural posture relevant to litigation likelihood

• The patent is recorded as Expired – Lifetime, with maintenance fees paid at the 4-, 8-, and 12-year intervals (FPAY events in 2004, 2008, 2011) and anticipated expiration on 2019-06-03. An expired patent cannot support an ongoing injunction, and damages would be time-barred for conduct long past.
• The only forward citations are two later Logan Clutch patents (US 6,848,347 and US 7,225,909), consistent with a small in-house portfolio rather than a patent that drew competitors' attention through litigation.
• Backward citations are US 4,644,819 (Leggett & Platt), US 5,657,843 (Midwest Brake Bond), and US 5,730,037 (Logan Clutch) — prior art of record, not litigation.

Confidence and caveats

• High confidence that no widely reported or database-visible litigation exists for US 6,148,976.
• The searches I ran did not directly return Unified Patents caselist, PACER, or CAFC docket pages for this patent; absence of hits in those general queries is not proof that no case has ever been filed. Federal district court suits involving a small privately held OEM like Logan Clutch (Westlake, Ohio) against an end-user or competitor could theoretically exist without broad web indexing.
• I therefore will not invent plaintiff/defendant names, jurisdictions, case numbers, filing dates, or outcomes. Providing those would require fabrication, which your instructions and mine prohibit.

Recommended next step for a definitive negative

To confirm the negative with docket-level certainty, I'd run a party-name search (not just the patent number) in:

• Unified Patents litigation portal — portal.unifiedpatents.com/litigation/caselist (search "Logan Clutch")
• PACER / CourtListener RECAP — party search "Logan Clutch Corporation"
• USPTO Patent Trial & Appeal Board — for any IPR/PGR/CBM
• CAFC docket search for "6148976" or "Logan Clutch"

If you'd like, I can draft the exact query strings for those databases, or once I have additional search budget, attempt targeted party-name lookups against CourtListener/Unified Patents to convert this "no evidence found" into a firmer negative.

I'll verify the ODP structured data against live sources before drafting.

Proceedings overview

Total AIA trial proceedings on file for US 6,148,976: 0 — the USPTO Open Data Portal structured block returns no IPR, PGR, or CBM proceeding for this patent as of the most recent ingest (checked 2026-09-12), so the breakdown is 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials, and there are no per-proceeding entries to enumerate below; the practical defensive posture for a defendant is therefore not "the patent is hardened," but rather "the patent has never been PTAB-tested and, more importantly, it is expired as of 2019-06-03 — there is no post-issuance validity record to borrow and no live infringement exposure for conduct after that date."

I ran targeted searches for IPR/PGR/CBM activity naming the '976 patent, naming the patent owner (Logan Clutch Corporation), and naming the patents in its citation/cited-by neighborhood; nothing surfaced. I could not query PTAB E2E or a commercial docket tool (Docket Navigator, Lex Machina) directly from this session, so treat the zero count as high-confidence but not court-certified — see verification steps in "Recommended next steps."

(no proceedings to enumerate)

Per the structured block, there is no {PROCEEDING_NUMBER} to populate. I am deliberately not inventing a proceeding number, panel, or FWD. For completeness, the template fields are resolved as follows:

• Type: N/A — no AIA petition filed.
• Filed: N/A.
• Status: N/A. (Note: this is distinct from the patent's legal status, which Google Patents records as "Expired - Lifetime," anticipated expiration 2019-06-03.)
• Judge panel: N/A — no panel ever assembled.
• Petition grounds: N/A.
• Institution decision: N/A.
• Final Written Decision: N/A — no FWD exists, and therefore no claim of the '976 patent has ever been canceled, confirmed, or held unpatentable by the Board. All 22 claims are untested, not sustained.
• Settlement / termination: N/A.
• Appeal: N/A — search of Federal Circuit materials surfaced no appeal involving this patent.
• Defensive value: the absence of a proceeding cuts both ways. It denies a defendant a ready-made invalidity record, but it also means no § 315(e)(2) estoppel constrains anyone and no Board finding of patentability exists to overcome.

Strategic summary

Claim status. All 22 claims are UNTESTED — none canceled, none sustained. Nothing has been narrowed. Structure, per the patent text itself (not per any FWD, because none exists): claim 1 (independent, clutch arrangement) with dependents 2–12; claim 13 (independent, method) with dependent 14; claim 15 (independent, kit-style "adapted to be positioned" arrangement) with dependents 16–22. The consequential point is that no Board decision has ever held claim 1 patentable or unpatentable, so a defendant cannot say "the patent has survived two IPRs and is hardened" and cannot say "claims 1–5 have been canceled." Both narratives are unavailable.

Estoppel landscape. Because no IPR/PGR/CBM was ever instituted, § 315(e)(2) estoppel never attached to any party or privy. Every prior-art basis remains open to a defendant — § 102 anticipation, § 103 obviousness, § 112 written description/enablement — subject only to ordinary district-court or ITC procedure. The trade-off is that invalidity must be proved by clear and convincing evidence in court rather than on the Board's preponderance standard, and there is no one-year statutory trial deadline forcing a decision.

The controlling fact is expiration, not validity. Per the bibliographic record, the '976 patent's anticipated expiration was 2019-06-03 (filing 1999-06-03; earliest priority 1998-06-09 by way of provisional 60/088,631). Legal events show maintenance fees paid at years 4, 8, and 12 and status "Expired - Lifetime," which is consistent with expiration by term rather than fee lapse — but confirm in Patent Center, since a fee lapse would change the date. Consequences for a defendant receiving a demand today (2026-09-12):

1. No injunctive relief is available on an expired patent.
2. § 286's six-year damages lookback is a dead end here. A complaint filed today could reach back only to 2020-09-12 — but the patent expired 2019-06-03, so there is no infringing activity in that window. Absent a much earlier-filed complaint, recoverable damages on this patent are effectively nil.
3. Assertion risk today almost certainly comes from a family member, not the '976. Logan Clutch's portfolio includes US 6,125,982 (threading clutch), US 6,050,162 (retrofit system), US 6,848,347, US 7,225,909, and later filings (2015 "Multi-spindle machine control system," 2019 "Clutch lubrication system," 2020 "Clutch assembly and system," 2023 "Modular drive apparatus"). Ascertain which patent number the demand actually identifies before building a defense — the era-2000 family members are also expired (e.g., US 6,848,347 filed 2000-02-04; US 7,225,909 filed 2003-11-26).

Pattern signals. No § 315(b) one-year clock is running, no serial petitioner exists, no defensive aggregator (Unified Patents, RPX) appears in the chain, and the patent owner is a small Ohio manufacturer of clutches, not an NPE. Notably, the two "Cited By" entries (US 6,848,347; US 7,225,909) are Logan's own later patents — consistent with a portfolio that has never attracted a third-party PTAB attack. The best invalidity anchors remain the examiner-cited art, principally US 4,644,819 (Leggett & Platt, 1987 — "High-low speed drive system for multiple spindle machines"), plus US 5,657,843 (Midwest Brake Bond) and US 5,730,037 (Logan Clutch); the 1985 priority date on US 4,644,819 also supports pre-AIA § 102(b) art positions and public-use/on-sale theories around the pre-1998 Davenport Model B machines.

Recommended next steps

• Do not litigate the '976 on validity-first premises. Lead with expiration and the § 286 damages window: if the demand identifies US 6,148,976 and no complaint predating 2019-06-03 exists, the demand letter has no damages theory left. Confirm the expiration date and any fee-lapse history in USPTO Patent Center: https://patentcenter.uspto.gov/.
• Verify the zero-proceeding finding yourself before relying on it in a brief. Run the patent number through PTAB E2E (https://ptab.uspto.gov/) using the "Patent Number" search field, cross-check the PTAB decisions/API feed, and run "6148976" through CourtListener (https://www.courtlistener.com/) to catch any Federal Circuit appeal or parallel district-court docket. The canonical Google Patents record is at https://patents.google.com/patent/US6148976/en.
• If, contrary to the record, an FWD or institution decision is found, it would be most-impactful-first (claims-invalidated proceedings at the top) and would change the estoppel analysis above materially — specifically, any instituted IPR would give the petitioner and its privies an § 315(e)(2) estoppel bar in the co-pending litigation.
• If instead an active proceeding turns up, calendar the statutory milestones: institution decision within six months of the petition's filing/accordance date, patent owner response, optional motion to amend, oral hearing, and the FWD due within one year of institution (extendable to 18 months for good cause under § 316(a)(11)).
• If no PTAB activity exists (the expected case), say so plainly and use the absence. Here the absence is a weak signal about validity and a strong signal about commercial relevance: well-asserted patents eventually attract IPRs, and this one apparently never did. That is consistent with a patent that was never a meaningful litigation weapon — which, combined with its 2019-06-03 expiration, makes an IPR-based defense unnecessary rather than merely unavailable. The residual caveat is that no IPR is a prerequisite to a district-court invalidity challenge, so if the patent owner does file, the full prior-art runway described above remains available on a clear-and-convincing standard.

I'll attempt to retrieve actual assignment records. Let me run several targeted searches.

Let me probe for assignment records, litigation, and any NPE-related activity.

Ownership & Assignment Analysis — US 6,148,976

Critical sourcing caveat (read first): I was unable to query the USPTO Assignment Center API directly with the tools available — assignmentcenter.uspto.gov and assignment.uspto.gov/patent are JavaScript single-page applications whose record data (reel/frame, correspondent) is not exposed to a plain web fetch. I ran targeted open-web queries against the patent number, the assignee, and the inventor, and no third-party index (Google Patents, Justia, patents-review.com, PlainPatent, or the assignee's own site) surfaced a single recorded assignment, reel/frame number, or correspondent of record for US 6,148,976. I therefore cannot report reel/frame entries, and I will not invent them. Everything below is limited to what the authoritative record and corroborating sources actually show. The reader should treat "no assignment found" as not found by me, not as confirmed none.

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Inventors

Pattern check — inventor attrition: No unusual departure pattern. Kalinsky is a career Logan Clutch engineer, not a departing founder. He is a named inventor on a continuous string of Logan Clutch filings spanning roughly two decades — e.g., US 5,730,037 (filed 1995, "Multi-Spindle Machine Control Systems"), the application here (filed 1999), US 6,518,769 ("Pick-up and back machining system for a multi-spindle machine"), US 6,626,072 (2003), the PTO clutch family (US 8,659,093 / US 8,839,933, 2011–2014), and the clutch-assembly filings of 2015–2016. He also recurs as a co-inventor with Scott W. Stevens, another long-tenured Logan Clutch inventor (Columbia Station, OH). A single-inventor patent from a ~20–50 employee family-owned OEM, with that same inventor still filing for the same assignee 17+ years later, is the opposite of the "all inventors exit within 12 months" fire-sale precursor.

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Original assignee

Logan Clutch Corporation, Westlake (Cleveland), Ohio. Original assignee and — per the record's own "Current Assignee" field — still the current assignee.

• Line of business: Original equipment manufacturer of hydraulically and pneumatically actuated industrial clutches, brakes, pump drives, and PTO clutches. SIC 3568 (Mechanical Power Transmission Equipment); NAICS 3336. Founded 1975 by William M. Logan; family-owned and operated, second generation.
• Does it ship product embodying the claims? Logan is a real, integrated manufacturer (sales, design, and manufacturing under one roof at 28855 Ranney Parkway). It explicitly lists US 6,148,976 as one of its own granted patents on its corporate site (loganclutch.com/patents-and-trademarks) and markets into the multi-spindle screw machine market — the exact application of this patent (the specification targets the Davenport Model B five-spindle automatic screw machine). This is strong evidence of an operating-company, product-backed patent, though I cannot independently confirm a specific catalog SKU that practices every claim limitation.
• Status as of 2026: Operating. Privately held, ~23–50 employees, estimated revenue ~$5–10M. No bankruptcy, no dissolution, no acquisition found. PitchBook lists it as private and "Generating Revenue." It took a 2020 PPP loan (per Salary.com), i.e., it weathered COVID as a going concern.

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Assignment timeline

The USPTO Assignment Center returned no records retrievable through my tools, and no secondary index exposed any recorded assignment for US 6,148,976. Accordingly I can report no reel/frame entries.

What the available evidence does establish:

• The record shows Original Assignee = Logan Clutch Corp and Current Assignee = Logan Clutch Corp — i.e., no change of ownership has been recorded or surfaced on the face of the patent record.
• The Google Patents legal-events table for this patent contains only grant and maintenance-fee events — STCF (2000-11-02, patent grant) and three FPAY fee payments (4-year, 8-year, 12-year) — with no assignment (AS) events. That is consistent with an owner that never transferred the patent after grant.
• All three maintenance fees were paid — year 4 (recorded 2004-05-17), year 8 (2008-05-21), year 12 (2011-12-29). The patent ran to its full 20-year term, anticipated expiration 2019-06-03, and is now Expired – Lifetime. A patent voluntarily carried to full term by a paying owner is a strong marker of retained strategic/commercial value to the original assignee, not an abandoned or dumped asset.

The only assignment I can infer — and I flag it as inferred, not recorded evidence — is the original inventor-to-assignee transfer (Robert M. Kalinsky → Logan Clutch Corporation), which necessarily underlies the grant to Logan Clutch as assignee. I have no execution date, no reel/frame, and no correspondent for it, so I am not listing it as a formal entry.

If a future query of Assignment Center returns records, the entries to look for are an original Kalinsky→Logan Clutch assignment from ~1999, and any post-2000 AS entries — but the legal-events table is already strong evidence that the latter do not exist.

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Timeline diagram

timeline
    title Ownership of US 6148976
    1998 : Provisional application filed
    1999 : Non-provisional application filed
    2000 : Patent issued to Logan Clutch Corp
    2004 : Four year maintenance fee paid
    2008 : Eight year maintenance fee paid
    2011 : Twelve year maintenance fee paid
    2019 : Patent expired full term

(Deliberately flat: the chain has a single owner throughout. No reassignment node exists to plot.)

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NPE / troll-pattern signals

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Verdict

Insufficient data — but with a strong operating-company overlay.

No recorded assignment beyond original ownership could be retrieved, which is the precise condition the rubric assigns to "Insufficient data (no records, or only the original assignment)." That said, every affirmative piece of evidence points the same direction: the patent was owned by Logan Clutch Corporation from grant to expiration, the Google Patents legal-events table shows only the 2000 grant (STCF) and maintenance fees paid at 4/8/12 years with no assignment events, and the patent ran to its full term ending 2019-06-03. The assignee is a 50-year-old family-owned Cleveland OEM that lists this patent on its own website and sells into the exact multi-spindle screw machine market the claims address. I found no NPE, no shell entity, no known asserter, no litigation, and no transfer of any kind.

Confidence and limits: I am highly confident there is no evidence of NPE activity. I am not able to certify that Assignment Center contains zero records, because I could not query it directly and no mirror exposed the data; a manual reel/frame verification is the one remaining gap. Correspondingly, I did not surface any CAFC 2026 docket entry or litigation for this patent — treat that as not found, not confirmed none.

Verify at:

• USPTO Assignment Center (search by patent number 6148976): https://assignmentcenter.uspto.gov/
• Assignment Search (mirror): https://assignment.uspto.gov/patent/index.html
• Google Patents legal events: https://patents.google.com/patent/US6148976/en
• Assignee's own patent listing (corroborates retained ownership): https://loganclutch.com/patents-and-trademarks

I'll run targeted searches on the specific cited references and the patent number itself.

Now let me check the closely related Logan Clutch family members that could bear on § 102(e), and confirm the US 4,644,819 record details.

Prior-Art Analysis — US 6,148,976

Scope note on the "USPTO database" search. I queried for the literal number 6148976 (and the bare digits "6148976"). What I could retrieve is the record mirrored by Google Patents (the authoritative full text supplied in the task prompt) plus secondary aggregator records (EveryPatent, FreePatentsOnline, Justia). I did not obtain a direct PatentCenter/Patent Assignment/Public-PAIR session view, and I could not pull the examiner's full Information Disclosure Statement or an examiner's search-strategy record. Two consequences: (a) the "prior art of record" I analyze below is the three references printed on the face of the patent as mirrored by the aggregator record; (b) I cannot rule out that additional 1.56/1.97 references were considered but not printed. I flag this rather than assert completeness.

Governing law. Priority is 1998‑06‑09 (provisional 60/088,631); the non‑provisional was filed 1999‑06‑03. The application was filed before 2013‑03‑16, so pre‑AIA 35 U.S.C. §§ 102/103 apply, including § 102(e) and the § 103(c) common-ownership carve‑out.

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1. References cited on the face of US 6,148,976

1.1 US 4,644,819 — the primary reference

Brief description. The patent discloses a multi‑spindle machine drive in which pneumatically operated disc clutches on a high speed shaft and a low speed shaft selectively couple the main drive shaft (expressly called "the large worm shaft") to one or the other, plus an optional pneumatically operated disc brake on the main drive shaft for independent braking. The specification states the low speed clutch "acts as a brake when engaged to rapidly decelerate the main drive shaft down to the speed of the low speed shaft," that the high/low clutch timing is "closely controlled so that the high speed pneumatic operated disc clutch is disengaged and the low speed pneumatic operated disc clutch is engaged practically instantaneously," and that the design is usable "for the retrofitting of existing machines." Its stated objects are cycle‑time reduction, elimination of a mechanical drag brake that "wore out too fast and had to be constantly adjusted," and improved tool‑slide position control. Sources: https://patents.google.com/patent/US4644819 and https://FreePatentsOnline.com/4644819.html

§ 102 mapping to US 6,148,976 claim 1:

• "a high speed clutch … in generally surrounding relation with a long worm drive shaft" → 4,644,819's high speed pneumatic disc clutch, but on the high speed shaft, not on the main/large worm shaft.
• "a snubbing clutch … in generally surrounding relation with the long worm drive shaft … to slow the rotation of the long worm drive shaft" → 4,644,819's pneumatic disc brake on the main drive shaft (and/or the low speed clutch's brake-like deceleration), which does act on the worm shaft.
• "a machine brake clutch … in generally surrounding relation with the starting clutch drive shaft" → no counterpart; 4,644,819's brake is on the main drive shaft, not on a starting-clutch/idler-sleeve shaft.
• "a starting clutch … in generally surrounding relation with a starting clutch drive shaft, … when engaged the machine is operable at the low speed" → 4,644,819's low speed clutch, but on the low speed shaft/idler gear sleeve, not on a "starting clutch drive shaft."
• "spaced longitudinally from…" limitations → not disclosed in the claimed pairing (4,644,819 affirmatively places its high and low speed clutches "in substantial radial alignment" inside the main housing — the opposite arrangement).

Conclusion for § 102: US 4,644,819 does not anticipate claim 1 (and therefore cannot anticipate dependent claims 2–12, all of which incorporate claim 1), nor claim 13 (method) or claim 15 (the "adapted to be positioned" form, which recites the identical four-element/two-shaft architecture). Its three-clutch topology (high speed clutch, low speed clutch, main-drive-shaft brake) on three different shafts does not read on the claimed four-clutch topology on two shafts. It is, however, the single most material reference and would be the natural primary reference for a § 103 attack on claims 1, 13 and 15, with the "snubbing clutch" and its longitudinal spacing being the features requiring a secondary teaching or a rationale (e.g., that using a dedicated, pressure-variable brake on the worm shaft to synchronize a high→low shift is an obvious design choice in view of 4,644,819's express cycle-time and drag-brake-wear motivations).

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1.2 US 5,657,843 — clutch/brake overlap timing

Brief description. A single‑speed press drive using a hydraulically actuated oil‑shear clutch on one side of a flywheel and a hydraulically actuated oil‑shear brake on the other. The brake is spring‑biased applied and the clutch biased disengaged; both are actuated from a single hydraulic pressure source, and the invention's point is precisely controlling the amount of overlap between brake release and clutch engagement (and tolerating "a dead zone" between them). Field: metal‑forming presses, not multi‑spindle screw machines. Sources: https://www.freepatentsonline.com/[5657843](/patent/5657843).html; https://patentimages.storage.googleapis.com/96/07/20/d2b543090bca8a/US5657843.pdf

§ 102 mapping to US 6,148,976:

• The only genuine points of contact are (i) a multi‑disc friction clutch/brake pair with coordinated actuation timing, and (ii) a normally‑applied brake / normally‑released clutch default state, which superficially resembles the 6,148,976 embodiment where de‑energized solenoid valve 42 routes air to the machine brake clutch 14 and its discs compress against cup 27 (spec., FIG. 2 discussion).
• It discloses no multi‑spindle machine, no timing shaft, no high/low drive trains, no starting clutch drive shaft, no long worm drive shaft, and no snubbing clutch. It is hydraulic, whereas 6,148,976 claim 2/16 requires pneumatic operation.

Conclusion for § 102: US 5,657,843 does not anticipate any claim of US 6,148,976 — not the independent claims and not any dependent claim (dependent claims inherit all limitations of claims 1/15 or claim 13). Its value is (a) as evidence that clutch/brake actuation‑overlap control was known, which is background for the claims 6/20 timer‑and‑limit‑switch theme, and (b) as a weak § 103 secondary reference. It cannot supply the pneumatics, the timing shaft, or the two‑shaft/four‑clutch architecture.

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1.3 US 5,730,037 — the control-system reference (commonly owned)

Brief description. A controller/control system for a multi‑spindle machine. Per the disclosed summary: at least two controllers at spaced locations, processors linked through a serial interface, sensors that shut down the main motor on fault detection, an administrative workstation with a database for production reports, and — critically here — claim 17, which recites a processor that "determines a position of said timing shaft from said encoder," a clutch pair in operative connection with the drive shaft and main motor "operative to change the speed of said drive shaft from a high speed to a relatively low speed and vice-versa," with the controller operative to shift the drive shaft high↔low and the shift points variable by operator inputs. Source: http://www.everypatent.com/comp/pat5730037.html

§ 102 mapping to US 6,148,976:

• Claim 7 / claim 21 ("an encoder … operative to communicate the position and rotational velocity of the timing shaft to the microprocessor, … the snubbing clutch solenoid valve is operative to be energized by the microprocessor for a selected time period") maps closely onto the 5,730,037 encoder‑/controller‑based shift‑point control, and 6,148,976 itself points to 5,730,037 for "further description of the encoder and controller."
• Claim 5 / claim 19 ("electrical circuit … operative to be controlled by a microprocessor") likewise maps onto the 5,730,037 controller.
• But 5,730,037 discloses a clutch pair (high/low) — two clutches — not the claimed four‑clutch arrangement with a discrete machine brake clutch on the starting clutch drive shaft and a discrete snubbing clutch spaced from the high speed clutch on the long worm drive shaft.

Conclusion for § 102: US 5,730,037 does not anticipate claims 1, 13 or 15 (and hence cannot anticipate any dependent claim, because every dependent claim incorporates one of those independent claims: 2–12 and 16–22 depend on 1 or 15; claim 14 depends on 13). It is, however, highly material § 103 art for the control‑side dependent claims — specifically claims 5, 6, 7, 19, 20 and 21 — and would be the obvious secondary reference when combined with US 4,644,819 to attack those claims. Practically, its incorporation by reference into the 6,148,976 specification also complicates any argument that the encoder/microprocessor subject matter was novel to Kalinsky.

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2. References NOT printed on the face of the patent that nevertheless bear on § 102

The task asks specifically about "each patent citation for 6148976." For completeness I note two same‑family items that a thorough § 102 study must address, while clearly labeling them as not part of the printed prior‑art citation list.

2.1 US 6,050,162 — "Multi-spindle machine retrofit system" (potential § 102(e) art, commonly owned)

• Full citation: US 6,050,162 A, Logan Clutch Corporation, inventor Kalinsky; App. Ser. No. 08/871,019, filed 1997‑06‑06; granted 2000‑04‑18. This is the "co‑pending patent application titled Multi-Spindle Machine Retrofit System" that 6,148,976's Background Art section incorporates by reference. Source: http://www.everypatent.com/comp/pat6050162.html
• Why it matters: Its application filing date (1997‑06‑06) precedes the 6,148,976 priority date (1998‑06‑09), so a granted claim could in principle be § 102(e) prior art. Its claims recite high speed clutch + feed clutch + brake clutch with an electrical control system, a timer counting down the brake‑engagement interval, limit‑switch or encoder determination of timing‑shaft rotational position, three solenoid valves, and "said timer is operative to send a signal to said controller which then sends signals to said solenoid valves."
• § 102 conclusion: It does not anticipate claims 1, 13 or 15 — it discloses a three‑clutch retrofit (no separate snubbing clutch on the long worm drive shaft, no starting‑clutch‑drive‑shaft brake clutch pairing). As to claims 6/20 and 21, the timer/limit‑switch/encoder themes overlap heavily, but the claims as a whole still require the four‑clutch architecture via their base claim.
• Important statutory caveat: Because US 6,050,162 and US 6,148,976 are commonly owned by Logan Clutch Corporation, § 103(c) (pre‑AIA) would disqualify the reference for obviousness purposes; the common ownership also gave the applicant options (e.g., 37 CFR 1.131‑type showings / terminal‑disclaimer practice) had the examiner raised it under § 102(e). The examiner did not list it on the face of 6,148,976.
• Contradiction to flag: One aggregator snapshot of US 6,050,162 lists a priority date of "1996‑06‑07", while the 6,148,976 specification and the US 6,848,347 specification both state Ser. No. 08/871,019 was filed Jun. 6, 1997. I am flagging this literally rather than silently choosing; the two are one year apart and the discrepancy matters for any § 102(e) date computation. On the face of the two Logan/Google records, 1997‑06‑06 is the better‑supported filing date.

2.2 US 6,125,982 — "Threading clutch for a multi-spindle machine" (same‑day sibling; NOT prior art)

• Full citation: US 6,125,982, Logan Clutch Corporation, inventor Kalinsky; App. Ser. No. 09/325,246, filed 1999‑06‑03; granted 2000‑10‑03. Claim 1 priority from provisional 60/088,632 filed 1998‑06‑09. Source: http://www.everypatent.com/comp/pat6125982.html
• Filed the same day as 6,148,976's application (09/325,247) and claiming the same‑date provisional benefit. Under pre‑AIA § 102(e)/(g) it is therefore not prior art to 6,148,976. Its significance here is evidentiary, not anticipatory: its background section is the source that expressly characterizes US 4,644,819 as describing "a high‑low speed drive system for multiple spindle machines employing selective engagement and disengagement of associated pneumatic operated disc clutches" — i.e., the same one‑sentence characterization in 6,148,976's Background Art.

2.3 Forward citations — not prior art

US 6,848,347 B1 (Logan Clutch, "Multi-spindle machine," priority 2000‑02‑04, granted 2005‑02‑01) and US 7,225,909 B1 (Logan Clutch, "PTO clutch assembly," priority 2003‑11‑26, granted 2007‑06‑05) cite 6,148,976; they post‑date it and are not prior art. Notably, US 6,848,347's specification in turn incorporates US 6,148,976 by reference — a further indication that 6,148,976 is a family anchor rather than an isolated filing. Source: https://patents.google.com/patent/[US6848347B1](/patent/US6848347B1)

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3. Summary table — § 102 exposure of US 6,148,976

Bottom line on § 102: On the record available to me, no cited reference anticipates any claim of US 6,148,976, and consistent with that, the patent issued with all 22 claims intact over this art. The closest any reference comes is US 4,644,819, and it fails on the claimed architecture — a discrete starting clutch and machine brake clutch paired on the starting clutch drive shaft, plus a discrete high speed clutch and snubbing clutch paired on the long worm drive shaft, with the two clutches on each shaft spaced longitudinally. The real exposure of this patent is under § 103, not § 102, and mainly against the control‑side dependent claims (5–7, 19–21) via US 4,644,819 in view of US 5,730,037.

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4. Contradictions and confidence flags

1. Internal inconsistency in the previously generated summary. It states "There are four independent claims — three apparatus claims (1, 15) and one method claim (13)." That enumerates only three independent claims (1, 13, 15). The claim text confirms three: claims 2–12 depend on 1; claim 14 depends on 13; claims 16–22 depend on 15. I treat three independent claims as correct and flag the prior section's count.
2. US 6,050,162 priority date discrepancy (aggregator "1996‑06‑07" vs. specification "Jun. 6, 1997"). Not resolved by the sources I retrieved; flagged, not auto‑corrected.
3. Inventor of US 4,644,819 ("Zugel") is taken from the reference table printed on US 6,125,982's front page; I did not read the US 4,644,819 front page directly in this session. Treat as secondary‑source.
4. Completeness of "prior art of record." My citation list is the aggregator‑mirrored list of three references. I did not obtain the underlying USPTO IDS/PTOL‑892. Additional considered‑but‑not‑printed references may exist.
5. "Expired – Lifetime" for 6,148,976 (anticipated expiration 2019‑06‑03; maintenance fees paid at years 4, 8 and 12) is as listed on the record; a lapsed/expired patent cannot be infringed prospectively, which is why no § 102/§ 103 challenge (IPR/CBM/reissue) is plausible now — any prior‑art analysis of this patent is historical/portfolio analysis rather than live‑dispute analysis.
6. No litigation found (consistent with the earlier litigation section); I did not identify any IPR/PGR/CBM, district‑court, or CAFC proceeding, and I am not asserting a confirmed negative.

I'll gather details on each prior-art reference of record so the §103 analysis is grounded in what each reference actually teaches.

Obviousness Analysis — US 6,148,976 under 35 U.S.C. § 103

Grounding note: This analysis uses the authoritative full patent text supplied for US 6,148,976 and the prior-art references identified in the "Prior Art" portion of that record. Details of the reference disclosures below come from search hits against FreePatentsOnline and Google Patents (URLs cited inline); where I could not verify a fact, I say so. Per the operating rules, identifiers are taken literally as written — including the claim typos "engaeable" (claim 1) and "engaseable" (claim 13), and "alone with snubbing clutch" (specification, describing FIG. 1).

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0. Flag on the previously generated sections

The earlier "Plain-Language Overview" states: "There are four independent claims — three apparatus claims (1, 15) and one method claim (13)." That sentence is internally inconsistent and the count is wrong. On the face of the patent there are three independent claims: claim 1 (apparatus, mounted form), claim 13 (method), and claim 15 (apparatus, "adapted to be positioned" retrofit form). Claims 2–12, 14, and 16–22 are dependent. I proceed on that basis. No other contradictions with the prior sections were identified.

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1. Legal framework and timing

• Governing law: The application was filed 1999-06-03 and claims benefit of provisional 60/088,631 filed 1998-06-09. Both dates precede 2013-03-16, so pre-AIA § 103(a) applies (Graham v. John Deere; KSR Int'l v. Teleflex, 550 U.S. 398 (2007)). KSR's rationales are equally usable as analysis tools regardless of which version of § 103 governs.
• Practical posture: The patent is recorded Expired – Lifetime, anticipated expiration 2019-06-03, with FPAY payments at years 4, 8 and 12. A § 103 analysis today is therefore retrospective — relevant to (a) whether the 1998–2000 family represented patentable subject matter at all, (b) whether the same subject matter could be asserted against later-filed improvements (e.g., the forward-cited US 6,848,347 and US 7,225,909, both Logan Clutch), and (c) defensive/invalidity analysis in a family dispute. It cannot support an injunction or ongoing damages.
• POSITA: A mechanical design engineer with ~3–5 years in cam-controlled automatic screw machines (Davenport-type multi-spindle machines) and power-transmission clutch/brake design, familiar with pneumatic multi-disc clutch/brake packs, solenoid valving, and cam/timing-shaft machine sequencing.

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2. Prior-art qualification

Everyone in the "Prior Art" section of the record is US patent art. Dates are taken from the record and the reference documents.

Consequence: The usable combination space is {4,644,819} ∪ {5,657,843, 5,730,037}. US 6,050,162 is off the table for § 103 — but this cuts both ways, because '162's substance (brake clutch + feed clutch + high speed clutch with a timer that applies the brake for a preset interval during the high→low shift) is the '976's closest conceptual relative and is not available to an examiner.

Note the specification's own admissions: the Background identifies US 4,644,819 as describing "a high-low speed drive system for multiple spindle machines employing selective engagement and disengagement of associated pneumatic operated disc clutches," and describes the co-pending application as already achieving cycle-time reduction with a control system. These are applicant statements about the state of the art that an examiner or challenger will use to frame the problem and the level of ordinary skill.

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3. What each reference actually teaches (element inventory)

US 4,644,819 — the primary reference

From the claims, abstract, and description (FreePatentsOnline; Google Patents):

• A high/low speed drive system for multiple spindle machines with a main housing, a main drive shaft "normally referred to as the large worm shaft," and high and low speed shafts.
• "Pneumatic operated disc clutches" that "when selectively engaged and disengaged drivingly connect one or the other of the high and low speed shafts to the main drive shaft." Claim 1 recites fluid-operated disc clutch means with clutch discs and clutch cages, and gear teeth on the cages meshing with each other and with a gear on the main drive shaft.
• Explicit braking/deceleration function: "the low speed pneumatic operated disc clutch acts as a brake when engaged to rapidly decelerate the main drive shaft down to the speed of the low speed shaft."
• Close timing of the shift: "the timing of both the high speed and low speed pneumatic operated disc clutches is closely controlled so that the high speed pneumatic operated disc clutch is disengaged and the low speed pneumatic operated disc clutch is engaged practically instantaneously."
• An optional dedicated brake on the worm shaft: claim 13 — "pneumatic operated disc brake means on said main drive shaft which provides for independent braking of said main drive shaft upon disengaging both said high and low speed shaft clutch means"; claim 11 — brake discs connected to the main drive shaft with a brake cage grounded to the main housing.
• Stated objects: "more rapid and precise changing of the main drive shaft speed from high idle speed to low machining speed and then back to high idle speed during each complete cycle of machine operation for increased machine production"; "more precise control over the end position of the tools relative to the work during rapid advance of the tools during idle"; "retrofitting of existing machines"; "simplified porting of air through lines on the same path to all of the clutches," with clutches "desirably located in close proximity."
• Not disclosed: a timing shaft; an electronic controller, timer, limit switch, or encoder; any clutch identified as a "starting/feed clutch" on a "starting clutch drive shaft"; two clutch elements on the same shaft spaced longitudinally (its high and low speed clutches are on separate shafts and instead are in "substantial radial alignment").

US 5,657,843 — the clutch/brake-coordination reference

(FreePatentsOnline; Google Patents):

• A press drive with an oil-shear brake assembly on one side of a flywheel and an oil-shear clutch assembly on the other, each being a multi-disc (multiple friction plate) pack.
• The point of the invention is controlled coordination between brake and clutch, including deliberate "overlap" between brake application and clutch engagement: the prior art's "inability to accurately control the amount of overlap between the operation of the brake unit and the operation of the clutch unit" is identified as the problem to be solved; "the separation of the two units provides the flexibility to design into the units the controlled coordination… to accurately provide specified amounts of overlap."
• Space/packaging motivation: separating the units and placing them on opposite sides of the flywheel "minimize[s] the amount of space required."
• Different actuation medium (hydraulic oil-shear, not pneumatic) and a different host machine (press, not multi-spindle screw machine) — the principal weakness as a § 103 partner.

US 5,730,037 — the control/encoder reference

(Google Patents; EveryPatent):

• A programmable controller for a multi-spindle machine with processor, display, operator inputs, and a plurality of sensors; sensors can shut down the main motor and display the fault.
• Claim 17 is directly on point: the processor "determines a position of said timing shaft from said encoder"; a "clutch pair is in operative connection with said drive shaft and said main motor… operative to change the speed of said drive shaft from a high speed to a relatively low speed and vice-versa," the clutch pair is in operative connection with the controller, "whereby said controller is operative to shift said drive shaft from high to low speed and vice-versa, and wherein said high and low speed shifts are variable by actuation of said operator inputs."
• Motivation language: "Shifting from high to low speed too early however may result in slower cycle times and production rates. The same result may occur if the shift from low to high speed is made too late… if the shift from high to low speed is made too late… damage to the machine, the tooling or the work pieces may result."

Important wrinkle: the '976 specification expressly directs the reader to this patent for the encoder/controller: "Further description of the encoder and controller is contained in U.S. Pat. No. 5,730,037 Mar. 24, 1998 the content of which is incorporated herein by reference." That incorporation does not neutralize the reference as prior art, but it does mean the '976 specification relies on '037's disclosure to support claims 7 and 21. In effect, the applicant is pointing at the prior art and saying "this is how you do the encoder embodiment."

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4. Independent claim 1 — element mapping and the combination

Claim 1 is an apparatus claim whose limitations are almost entirely structural-plus-capability ("selectively operative to…"). It does not require pneumatics, electronics, a timer, an encoder, a limit switch, a bracket, or any torque value. That narrowness helps the patent only if the arrangement itself is non-obvious.

Do any of the three references anticipate claim 1? No. US 4,644,819's architecture is three torque-control elements on three different members (high-speed-shaft clutch, low-speed-shaft clutch, main-drive-shaft brake). Nothing of record discloses two separately-actuatable clutch packs spaced longitudinally on a single worm shaft plus two more packs on the starting clutch drive shaft. Claim 1 therefore rises or falls on § 103, not § 102.

The combination and the motivation (KSR rationales)

Primary combination: 4,644,819 + 5,730,037 (optionally + 5,657,843).

(a) Same field, same problem, same express objective. 4,644,819's stated object — "more rapid and precise changing of the main drive shaft speed from high idle speed to low machining speed and then back to high idle speed during each complete cycle of machine operation for increased machine production" — is the '976's stated object ("lowers the cycle times for increasing production"). 5,730,037 addresses the identical machines and the identical shift-timing problem, and expressly warns that late high→low shifts damage the machine/tooling. A POSITA working on a Davenport-type machine would consult both as a matter of course; the '976 specification itself treats both as the relevant prior art.

(b) Combining prior-art elements per known methods, predictable results. Both '819 and '843 disclose clutch and brake packs mounted coaxially on drive members, with discs compressed against cups/drums and (in '819) cages grounded to the housing. Placing an existing pneumatic multi-disc brake pack coaxially on the worm shaft, and an existing pneumatic multi-disc clutch pack on the same shaft, is the assembly of known elements with no change in their respective functions. '819 supplies the express motivation via its "if desired" pneumatic disc brake on the main drive shaft — i.e., the reference itself suggests putting a grounded brake on the very shaft the '976 calls the long worm drive shaft.

(c) Substitution of one known braking element for another. '819 uses the low-speed clutch itself as the decelerator ("acts as a brake… to rapidly decelerate the main drive shaft down to the speed of the low speed shaft"). The '976 replaces that function with a dedicated grounded brake (snubbing clutch 22 on bracket 36). Substituting a known, purpose-built disc brake for a clutch being used as a brake is a classic predictable-result substitution, and '819 renders it doubly obvious by disclosing the substitute itself in claim 13.

(d) Known technique to improve a similar device in the same way (encoder/controller for '037; timed brake overlap for '843). '037 already teaches controlling the high/low shift electronically from timing-shaft position/velocity, with the shift points programmable by operator input — the '976's claims 5–7 and 19–21. '843 teaches that brake application may be deliberately overlapped with clutch release and that the overlap is controllable — precisely the '976's "activates the machine brake clutch 14 and snubbing clutch 22 for a predetermined time period to cause the drive train gears to slow down allowing synchronous meshing."

(e) "Obvious to try" over a finite set of solutions. Given '819's teaching that the high→low transition is the cycle-time bottleneck and that deceleration of the worm/main shaft is the lever, a POSITA faces a small, enumerated set of design choices: brake the worm shaft, brake the starting clutch drive shaft, or brake both. Trying the disclosed alternative (worm-shaft brake) and then a second brake on the upstream clutch shaft is the kind of finite, predictable variation KSR treats as obvious.

(f) Express design incentive for the second brake. The '976's machine brake clutch 14 exists because, in the '976's layout, the starting clutch drive shaft is the input to the high-speed path (via quick index drive gear 32/gear 30). '819 already teaches that the driving member of the high-speed path must be decelerated before low-speed engagement, and that the deceleration must occur "practically instantaneously." Applying braking to the upstream shaft of that path is a mechanical consequence of where the shaft is in the power flow — the sort of reason-driven rearrangement KSR credits.

Weakest link in the chain: the relocation of the high speed clutch onto the worm shaft (with the driven gear freewheeling until engaged) is not shown in '819 and is not an equivalence argument — it changes which member is directly coupled to the worm shaft. A challenger must argue this is a predictable design choice (mounting a clutch on the driven shaft so the driven gear freewheels when disengaged is standard in the clutch art, and the '976's own gear-30/cup-34 arrangement is described in exactly those conventional terms). A patent owner will argue this relocation is the heart of the invention and that neither reference suggests it. This is the pivot point of any real § 103 dispute over claim 1.

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5. Independent claims 13 and 15

Claim 13 (method). The steps are the operational counterpart of claim 1: engage the starting clutch (low speed), engage the machine brake to slow that shaft when the starting clutch is disengaged, engage the high speed clutch to rotate the worm shaft (high speed), and engage the snubbing clutch to slow the worm shaft when the high speed clutch is disengaged. If claim 1's arrangement is obvious, claim 13 is obvious: each recited step is the inherent or expected operation of the corresponding structure, and no step recites an unexpected order, timing, or parameter (the timer/limit-switch timing lives in claims 6 and 20, not claim 13). Under the familiar principle that a method claim reciting steps inherently performed by a known apparatus is unpatentable over that apparatus, claim 13 adds essentially nothing to the claim 1 analysis. Note the drafting defect "engaseable" in claim 13's brake-clutch limitation — a § 112(b) irritant, not a § 103 defense.

Claim 15 (apparatus, "adapted to be positioned"). Functionally identical to claim 1; the only difference is contemplated-installation format. Two points:

• A claim to a component "adapted to be positioned" on a shaft is measured against the same prior art; intended use does not patentably distinguish structure.
• Even taken as a retrofit claim, the objective of retrofitting is expressly in the prior art: '819 states the pneumatic disc clutches "can readily be used on both new multiple spindle machines and for the retrofitting of existing machines," and '976's own Background describes the retrofit context. Retrofitting to the prior-art arrangement would be an obvious commercial objective. (US 6,050,162's retrofit claims would have been the natural § 103 partner for claim 15 — but, as shown in § 2, it is not available as prior art. That unavailability is a meaningful gap in any challenge to claim 15, even though it changes nothing about claim 1.)

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6. Dependent claims — graded vulnerability

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7. Nonobviousness defenses to expect, and how they fare

1. "No reference teaches or suggests two clutch/brake packs on one shaft." Partially true of '819 alone. Rebuttal: '843 expressly arranges a clutch pack and a brake pack coaxially to minimize space, and '819 claims a brake grounded on the worm/main drive shaft; putting a second pack on the same shaft is packaging, and the '976 specification offers no unexpected result from the spacing itself (only from the timing of actuation, which is the subject of claims 6 and 20, not claim 1).

2. "The references are non-analogous / from different fields." Weak. '819 is the same field (multi-spindle machine high/low drives) and is a § 102(b) reference to the same problem. '843 is a clutch/brake drive — the same art of multi-disc fluid-actuated clutch/brake packs; reasonableexpectation of success in mating such packs to a machine drive is high. '037 is not merely analogous; it is the same machine type and is incorporated into the patent's own specification.

3. "Different actuation medium — '843 is hydraulic, the claims require pneumatic." A genuine but limited point for the claims that require pneumatics (2, 3, 14, 16, 17). Rebuttal: pneumatics come from '819; '843 is relied on only for the brake/clutch coordination and coaxial packaging teachings, which are medium-independent.

4. "Teaching away." '819 contains one line that a patent owner will quote: one object is to "eliminate the need for a conventional friction brake and its attendant problems." But the full context shows this is directed at the prior wrap-around drag brake whose friction coefficient drifted with heat; the same document discloses, and claims, an independent pneumatic disc brake on the main drive shaft as an optional feature. A disclosure of an element the reference itself offers as optional is not a teaching away.

5. Secondary considerations. None are in the record I retrieved, and any cycle-time or market-acceptance argument would need a nexus to the claimed arrangement rather than to unclaimed features (the pressure controllers, the timer, the specific 0.8→0.6 s improvement cited in the sibling threading-clutch patent US 6,598,982/6,125,982-family disclosure). Logan Clutch's dominance of the Davenport retrofit market might support an industry-recognition story, but I found no evidence of record (e.g., licensing, awards, copying) to support it, and I would not assert it.

6. "The primary reference was considered and the claims allowed." 4,644,819, 5,657,843 and 5,730,037 all appear on the face of US 6,148,976, so the examiner had them. That fact suggests the examiner viewed the specific four-clutch, two-shaft arrangement as non-obvious. I could not retrieve the file wrapper or any office action, so I cannot tell whether the allowance rested on the snubbing-clutch placement, the retro-fit claim format, or something else. This is the single biggest evidentiary gap in the analysis.

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8. Bottom line

• No single reference anticipates claims 1, 13 or 15. 4,644,819's three-element, three-shaft architecture does not read on the '976's four-element, two-shaft architecture.
• Claims 2–8, 11–14, 16–19 are strongly vulnerable to a 4,644,819 + 5,730,037 (+ 5,657,843) combination. Every one of those limitations is either disclosed in '819 or would have been obvious to derive from '819 plus '037, and the patent's own specification points to '037 for the encoder/controller embodiment.
• Claims 6, 7, 20 and 21 are the most exposed to KSR. '037 claim 17 is, for practical purposes, a programmed high/low shift keyed to timing-shaft position from an encoder, and the '976 claims a microprocessor-energized snubbing/high-speed solenoid based on that same input.
• Claims 9, 10 and 22 (variable-pressure torque capacity) are the most defensible, because the combination of record supplies only general pressure-modulation teachings and no individual per-clutch torque-capacity schedule. Note that the numeric torque tables in the specification are not in the claims, so they cannot rescue the claim scope.
• The true battleground is claim 1's arrangement: the relocation of the high speed clutch onto the long worm drive shaft (with a freewheeling driven gear) plus two grounded brakes on two different shafts, and the corresponding method and retrofit claims. A challenger needs a reference — beyond what is in this record — showing a clutch pack and a brake pack on a common driven shaft in a machine-tool drive, or specific motivation for the relocation. If US 6,050,162 were usable art it would close much of that gap, but as shown it is not prior art (identical inventive entity, same assignee, and post-filing publication).

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9. Gaps and confidence

• Not verified: the actual prosecution history (office actions, rejections, reasons for allowance) for application 09/325,247; I had no USPTO PatentCenter/file-wrapper access. My statement about what the examiner considered rests solely on the cited references printed on the patent face.
• Not verified to full certainty: the inventorship of US 5,730,037. The U.S. reference table reproduced in the US 6,050,162 record lists "Manning," which would make it a different inventive entity and therefore "by another" prior art; the '976 specification independently characterizes it as assigned to the same assignee (implying different inventors). If (contrary to the record) Kalinsky were the sole inventor of '037 as well, it could not be 102(a)/(e) art, and claims 5–7 and 19–21 would lose their strongest obviousness reference. This should be confirmed before relying on '037 in a validity challenge.
• Statutory detail stated from general knowledge, not from retrieved primary sources: the pre-AIPA/AIPA effective-date distinction for § 103(c) common ownership of 102(e) art (AIPA changes applying to applications filed on or after 1999-11-29). I flag it as such; it is moot here because the "by another" requirement fails independently for US 6,050,162.
• Secondary-considerations evidence: none located; I make no evidentiary assertions about commercial success, copying, or industry praise.
• Reference disclosures: drawn from FreePatentsOnline and Google Patents pages for US 4,644,819, US 5,657,843, US 5,730,037 and US 6,050,162 (URLs cited above), plus the authoritative full text of US 6,148,976. Quoted phrases are as they appear in those sources. Where I inferred a mapping (e.g., that '819's "main drive shaft (normally referred to as the large worm shaft)" corresponds to the '976's "long worm drive shaft"), I have flagged it as an inference rather than a quotation.