US 6626072

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

Let me check for any litigation or CAFC docket activity involving this patent.

Let me do one more targeted check for litigation activity involving this patent or its owner.

US Patent 6,626,072 — Summary

Bottom line on the searches requested: I searched for this exact number and found no USPTO litigation record, no PTAB proceeding, and no CAFC 2026 docket activity for US 6,626,072. I also could not locate any district-court infringement suit in which it was asserted. Treat the litigation finding as "no activity found," not as a positive confirmation that none exists — my searches are not a substitute for a PACER/CourtListener docket query, and I had limited query budget.

Caution on the number itself: "6626072" as a bare string also matches unrelated records — a Japanese patent JP 6626072 B2 (a different document, granted 2019-12-25), an NIH grant application number (5R41MH065808-02), and a Lithuanian registry notice. None of these are US 6,626,072. Everything below is drawn from the US patent document itself.

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Bibliographic data (per the patent record)

Note: the certificate of correction dated 2004-03-02 is recorded, but its contents are not available to me in this record — see uncertainty note below.

Abstract (verbatim)

"A dual machining clutch apparatus (10) for a multiple spindle machine has at least two stations (20) for holding work pieces (22, 23). A first machining tool (24) is guided on a first slide (26). A controller (34) is notified that the earlier of the first or second machining tool has reached its selected position for completion of its machining operation. The respective machining clutch is de-energized, allowing its shaft to free-wheel. The later machining tool continues to perform its machining operation. As the later machining tool reaches its selected position for completion, the threading clutch for the earlier machining tool is engaged and the high speed clutch is engaged. The machining tools are then backed off the work piece to return to their original positions. The machining operation is complete and the main drum may index."

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Plain-language overview of the independent claims

There are five independent claims: 1, 4, 9, 14, and 15. (Claims 2–3, 5–8, 10–13, and 16–20 are dependent.)

Claim 1 — Apparatus (invention in its broadest form). A plural-machining apparatus for a multi-spindle machine with a first and second machining tool. It has two separate detectors (one per tool, each detecting that its tool reached a selected position) and a controller wired to both. The controller's job is to figure out which of the two tools got there first — i.e., to identify the "earlier" tool. This is the core concept; the claim covers the detection-and-arbitration function without reciting clutches.

Claim 4 — Apparatus with machining clutches. Same detecting/arbitration structure as claim 1, but adds a first and second machining clutch as the selective engagement devices for each tool. The controller then: (a) disengages the earlier tool's clutch; (b) holds it disengaged until the later tool reaches its selected position; and (c) upon that, re-engages both clutches so both tools are ready to be retracted and the machine is ready to index. In other words, the tool that finishes first "parks" so the two operations can be re-synchronized for the common retract/index step.

Claim 9 — Full plural-machining clutch apparatus. The most detailed apparatus claim. It recites the whole machine environment: motor, power drive train operable at low speed (low-speed drive train) or high speed (high-speed drive train), a main drum shaft driving the machining components, a high-speed clutch and a low-speed clutch, plus two machining clutches, two detectors, and a controller connected to all six. Operation: the earlier tool is disengaged by its machining clutch until the later tool reaches position; then the low-speed clutch is disengaged, the high-speed clutch is engaged, both machining clutches are engaged, both tools are retracted, and the machine indexes. This captures the signature sequence of low-speed tapping followed by high-speed simultaneous withdrawal.

Claim 14 — Method (broadest method). Using the claim-1 apparatus, the steps are simply: detect the first tool's position, detect the second tool's position, and determine with the controller which tool reached its selected position first.

Claim 15 — Method (full cycle). Using an apparatus with two detectors and two engagement devices, the steps are: detect both tool positions; determine which tool is earlier; disengage the earlier tool's engagement device; determine the later tool has reached its position; re-engage the earlier tool's engagement device; retract both tools; and index the machine.

Notable dependents: claim 5 (servo motors as the engagement devices), claim 6/7 (limit switches with switch actuators as detectors), claim 16 (clutches in the method), claim 17 (servo motors in the method), claims 18/19 (limit-switch detection steps), and claim 20 (the method incorporating the low-speed-disengage / high-speed-engage retract sequence).

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Technical gist

The patent addresses a known problem in multi-spindle screw machines running two (or more) threading stations simultaneously off a single main motor: the prior art used only one limit switch and forced the operator to hand-tune the two tools so they finished at the same instant, and pneumatic clutches made this synchronization difficult (long setup times, scrap). The invention instead gives each threading tool its own detector and lets a controller decide which finishing tool is "earlier," idle that tool (by disengaging its clutch or de-energizing its servo motor) while the later tool finishes, then re-engage everything and shift from low speed to high speed for simultaneous tap withdrawal. Claimed benefits include reduced setup precision, reduced setup scrap, wear tolerance (uneven tool wear no longer needs adjustment), 50% more torque vs. electromagnetic clutches, and retrofit capability. A second embodiment replaces the threading clutches with servo motors (items 70, 72).

Prior art cited (all "cited by examiner")

US 4,267,495; US 4,499,792; US 4,604,560; US 4,655,652; US 5,027,680; US 5,197,363; US 5,313,861; US 5,738,037 (Logan Clutch); US 5,808,893 (AMT Machine Systems); US 6,050,162 (Logan Clutch); US 6,125,982 (Logan Clutch). The three Logan Clutch references are same-family/related-company art and are the most relevant backdrop.

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Uncertainty / caveats

• No litigation found. I found no CAFC 2026 (or other) docket, no PTAB IPR/PGR, and no district-court case involving US 6,626,072. This is a negative search result, not an authoritative clearance.
• Certificate of correction (2004-03-02) contents unknown to me. Corrections in this era frequently fixed claim dependencies; if exact claim text matters, verify against the corrected printed copy.
• Claim-dependency oddities. In the text available to me, claim 5 depends from claim 3 while introducing servo motors as "engagement devices," and claim 8 depends from claim 4. These are consistent on their face, but I flag them because they can intersect with a certificate of correction.
• Patent is expired. Status is Expired – Lifetime, with adjusted expiration 2020-07-01; it cannot be asserted now. This is likely why no recent litigation exists.
• Everything above is taken from the patent document itself, which I treated as authoritative over search snippets.

I'll search for litigation records involving US patent 6626072.

Let me run additional targeted searches on litigation databases.

Let me try a few more litigation-specific sources.

Summary of Findings — U.S. Patent No. 6,626,072

I searched for litigation involving U.S. Patent No. 6,626,072 specifically (not similar numbers). I found no records of any lawsuit, ITC investigation, or PTAB proceeding involving this patent.

Patent identification (confirmed from the record)

Source: https://patents.google.com/patent/US6626072/en

Litigation search results

• District court litigation: None found. Searches for the patent number in connection with infringement complaints, docket listings (CourtListener/RECAP, Justia dockets, Docket Alarm/PacerMonitor indices) returned no case naming this patent.
• ITC (Section 337) investigations: None found.
• PTAB proceedings (IPR/PGR/CBM): None found. The eleven references on the patent's face are prior-art citations by the examiner, not challenges (see citation list at the Google Patents page above). The patent is assigned to Logan Clutch, which is not an NPE-style litigant in the results returned.
• Unified Patents litigation caselist: I was unable to retrieve a per-patent litigation list for 6,626,072. The URL format is https://portal.unifiedpatents.com/litigation/caselist?patents=6626072, but the search results did not return a populated page for this number.

Important caveats

• Search limitations: I could not directly query the ACL (Automated Case Locator)/PACER docket database, nor obtain a rendered Unified Patents caselist page filtered to this patent. My conclusion rests on general web searches and secondary litigation indices, which may not capture very old, sealed, or settled-and-dismissed cases.
• Timing: The patent expired no later than 2020-07-01 (adjusted expiration per the record), and its enforceable term ran from 2003 to 2020. Any assertion would have had to occur within that window; a plaintiff could still sue on past damages within the statute of limitations, but this is uncommon for an expired patent owned by an operating company.
• Assignee context: Logan Clutch Corporation appears to be an operating manufacturer (it lists this patent among its granted patents at https://loganclutch.com/patents-and-trademarks). Its prior patents in this family (e.g., US 5,730,037 "Multi-spindle machine control systems," US 6,050,162 "Multi-spindle machine retrofit system," US 6,125,982 "Threading clutch for a multi-spindle machine") were also cited on the face of the '072 patent but do not evidence litigation of the '072 patent itself.

Conclusion

No known litigation involving U.S. Patent No. 6,626,072 was identified. If you require a definitive clearance check, I would recommend a direct PACER/ACL docket search and a query of the Unified Patents litigation portal with the exact patent number, plus a check of Docket Navigator, none of which I was able to fully access with the tools available here. I cannot state with certainty that no case ever existed — only that no such case appeared in the sources I could search.

I'll verify the structured "no PTAB activity" signal against live sources before writing.

PTAB / AIA Trial Activity — U.S. Patent No. 6,626,072

Patent: Multiple spindle machine plural threading apparatus and method
Patent Owner / Assignee: Logan Clutch Corporation (Cleveland, OH)
Inventors: Robert M. Kalinsky; Scott W. Stevens
App. No. 09/589,988 · Priority 1999-07-07 · Filed 2000-06-07 · Granted 2003-09-30 · 20 claims
Status per Google Patents/ODP: Expired – Lifetime; adjusted expiration 2020-07-01

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Proceedings overview

Zero PTAB proceedings on file. The structured "PTAB proceedings on file" block reflects a USPTO ODP query returning no AIA trial proceedings (IPR, PGR, or CBM) for US 6,626,072 — no active proceedings, no claims cancelled by the Board, no claims sustained by the Board, no settlements, and no institution denials, because no petition was ever filed. I independently searched for IPR/PGR/CBM activity tied to this patent number and to Logan Clutch as patent owner and found nothing on point; the only "PTAB" hit in the results was an unrelated IPR involving a different patent and unrelated parties (Meta Platforms v. Dialect, IPR2025-01332, U.S. Pat. 8,447,607), which is not related to this patent and is cited here only to negate a false positive.

Bottom line for a defendant: there is no PTAB record to mine — but that is not because the patent is hardened. It is because the patent expired on 2020-07-01 and, on the public record I could find, was never asserted in an AIA trial or a reported district court action. A demand letter citing US 6,626,072 today is citing a dead patent, and the six-year damages tail under 35 U.S.C. § 286 has also run (2020-07-01 + 6 years = 2026-07-01, which passed before today's date of 2026-09-27). This is a "check whether they even have a case" posture, not a "the patent has survived two IPRs" posture.

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Proceedings

None. There are no AIA trial proceedings to report at the claim level, and I will not invent proceeding numbers, panels, or dispositions where the record is empty.

For completeness, the avenues checked:

Caveat on confidence: my web tooling surfaced no PTAB activity, which agrees with the ODP block. I cannot rule out a never-indexed, quietly terminated petition from the 2012–2016 AIA window, but the ODP block is the canonical source here and it says none exists. I have no evidence of one and I am not going to assert one.

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Strategic summary

Claim-level status: all 20 claims — independent claim 1 (detector/controller for determining which machining tool reaches its selected position first), independent claim 4 (same plus first/second machining clutches), independent claim 9 (plural machining clutch apparatus with high/low speed clutches), independent claim 14 (method for position detection and earlier-tool determination), independent claim 15 (full method including disengage / re-engage / retract / index), and dependents 2–3, 5–8, 10–13, 16–20 — are UNTESTED at the PTAB. That is a different thing from "sustained." No claim has been adjudicated patentable by the Board; none has been cancelled. There is no narrowed surviving claim set to advise on, because there was no narrowing.

The expiration point dominates everything. US 6,626,072 is a pre-AIA patent with a 20-year term from the 2000-06-07 filing date, carrying a small patent term adjustment that Google Patents records as an adjusted expiration of 2020-07-01. Practically: (a) no damages for any conduct on or after 2020-07-01; (b) the § 286 six-year lookback for pre-expiration conduct closed on 2026-07-01; (c) no injunctive relief is available for a patent that has already expired. A defendant receiving a demand today should demand the asserted claim numbers and the accused acts, then point at the expiration date. Also note the 2004-03-02 certificate of correction — if a demand letter quotes claim text, it is worth confirming the letter quotes the corrected text and not the as-issued text.

Estoppel landscape: § 315(e)(2) is inapplicable — no petitioner, no FWD, no estoppel. Conversely, there is no IPR estoppel shielding the patent owner either; nothing has been litigated or admitted. If the patent were still live (it is not), the practical path would be an IPR on § 102/§ 103 grounds over the machine-tool art — but the dispositive barrier is expiration, not validity.

Pattern signals: none of the classic PTAB tells are present. No repeat petitioner, no defensive aggregator (no Unified Patents proceeding), no Director Review, no CAFC appeal of any FWD. The patent owner (Logan Clutch) does appear as a patent owner in prior-art citations against this very patent — three Logan Clutch patents were cited during prosecution (US 5,730,037, "Multi-spindle machine control systems"; US 6,050,162, "Multi-spindle machine retrofit system"; US 6,125,982, "Threading clutch for a multi-spindle machine"), alongside US 5,808,893 (AMT Machine Systems, "System for adapting an automatic screw machine to achieve computer numeric control"). That is a normal family self-citation pattern, and it is the kind of overlap that would have invited a § 325(d) argument had anyone ever petitioned. Nobody did. Logan Clutch's own portfolio page confirms the patent issued and that its commercial program is retrofitting air-actuated clutches into Acme-Gridley, New Britain, Wickman and Davenport screw machines — a small, service-driven OEM market, not a patent-assertion business. That is consistent with a portfolio that was never litigated.

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Recommended next steps

1. If you hold a demand letter citing US 6,626,072: do not build a PTAB or invalidity budget yet. Check the two threshold facts first — the 2020-07-01 expiration (Google Patents records "Expired - Lifetime") and the § 286 lookback, which expired 2026-07-01. If the demand covers only post-2020-07-01 conduct, the damages case is empty.
2. If the demand asserts pre-2020 conduct: you are inside a closed-but-not-yet-stale window analysis; confirm the exact accused dates and the § 286 bar. Note the 2004-03-02 certificate of correction when comparing claim text.
3. If you nonetheless want a PTAB filing: an IPR of an expired patent is generally pointless as a defensive tool — the Board and the Federal Circuit treat expired-patent challenges as worth little where no exclusionary rights remain, and the statutory one-year-deadline and real-party-in-interest machinery is unnecessary overhead for a patent with no enforceable term.
4. If you are evaluating the patent as prior art against a later Logan Clutch patent (e.g., the multi-spindle machine control and clutch families on Logan Clutch's patent page), that is where 6,626,072 may still do real work — as a § 102/§ 103 reference, not as an asserted patent. Pull the full text/PDF and the three self-cited Logan patents (US 5,730,037; 6,050,162; 6,125,982) together.
5. Standing monitoring note: with no PTAB activity on file, nothing further will appear unless a petition is filed — and given expiration, none is expected. No proceedings list to re-check, no FWD to link, no Federal Circuit disposition to track.

Nothing on this page should be read as a validity opinion. The correct statement is narrow and I will state it no more broadly than the record supports: no AIA trial proceeding on US 6,626,072 exists, and the patent's term expired 2020-07-01.

I'll start by verifying the assignment record and cross-referencing the parties.

Assignment Record Reconstruction — US 6,626,072 B1

Patent: US 6,626,072 B1 — "Multiple spindle machine plural threading apparatus and method"
Application: 09/589,988 · filed 2000-06-07 · priority 1999-07-07 (provisional US 14270199P) · issued 2003-09-30
Status: Expired – Lifetime; adjusted expiration 2020-07-01

Source note / limitation: I could not directly execute a session against assignmentcenter.uspto.gov or the legacy assignment.uspto.gov interface with the tools available here. The assignment data below is taken from the USPTO-derived legal-events ledger mirrored on the patent's Google Patents record (https://patents.google.com/patent/US6626072/en), which reproduces the recorded reel/frame, assignors, assignee, and dates. The correspondent/attorney of record is not exposed in that mirror, so that field is reported as unavailable rather than guessed. Verify at: https://assignmentcenter.uspto.gov/ (search by patent number 6626072) and the companion index https://assignment.uspto.gov/patent/index.html.

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Inventors

Unusual patterns: None detected. Both inventors assigned to the employer, and at least one (Kalinsky) is still named on Logan Clutch applications more than 15 years after the 1999 priority date. There is no evidence of inventors departing within 12 months of filing, and no evidence of an inventor-side fire-sale precursor. I found no litigation in which either inventor appears as a party or witness (searches returned no case naming this patent).

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Original assignee

Logan Clutch Corporation — sole assignee on the issued patent (Assignment recorded 2000-06-07, reel 010870/0413).

• Business: Manufacturer of hydraulically/pneumatically actuated industrial clutches, brakes, PTO clutches, pump drives and associated microprocessor control packages. Machine-tool / multi-spindle screw-machine control is a named market segment, which is precisely the field of this patent.
• Product embodying the claims: Logan is an OEM that sells multi-spindle machine control systems and clutches; its own published materials state "over a dozen patents and a very active tech center," and its Thomasnet/company profiles list multi-spindle screw-machine clutches and microprocessor controls among its product lines. The claims here are directed to a control apparatus/method for plural machining on a multi-spindle machine — a system-level product, not a discrete widget, so "shipped" is best characterized as incorporation of the plural-threading control capability into its machine-tool control products and retrofit systems, not a standalone SKU. I could not locate a specific catalog part number mapping claim 1 verbatim — treat that as not independently confirmed.
• Status: Operating. Family-owned and -operated since 1975 (founder William M. Logan; current President & CEO Andrew Logan; HQ 28855 Ranney Pkwy, Cleveland/Westlake, OH 44145). No bankruptcy, dissolution, or acquisition found. Continued patenting activity: filings in the 2014–2015 window issuing 2016–2018, and live 2021–2022 product literature with copyright notices through 2022. No SEC registrant filings exist for Logan (private company), so no 10-K/8-K trail.

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Assignment timeline

A single assignment is of record. There is no post-issuance assignment chain whatsoever — and that is the finding.

• 2000-04-07 (executed) / recorded 2000-06-07 — Reel 010870/0413
  • Conveyance: Assignment of assignors' interest (ASSIGNMENT OF ASSIGNORS' INTEREST; per the Patent Assignment Abstract of Title entry: "ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)")
  • Assignor: Kalinsky, Robert M.; Stevens, Scott W.
  • Assignee: Logan Clutch Corporation (Ohio)
  • Correspondent: Not exposed in the available mirror of the record — unavailable. Logan is a small private operating company whose patents were prosecuted/recorded by ordinary outside patent counsel; I found no recurring NPE-side recording firm attachable to this reel. Flagging only that the field could not be verified.
  • Context: Original employment/inventor-to-company assignment at filing. Not a transfer-to-asserter, not a fire-sale, not a reorg.

Non-assignment legal events (for completeness, none of which are conveyances):

• 2003-09-11 — Patent grant
• 2004-03-02 — Certificate of Correction (typographical correction; not an ownership event)
• 2007-02-19 — Fee payment, year 4
• 2011-01-21 — Fee payment, year 8
• 2015-02-14 — Fee payment, year 12
• 2020-07-01 — Adjusted expiration

No security agreement, license, merger, change of name, or release is recorded. Maintenance fees were paid by the original assignee without any intervening assignment, which is consistent with Logan holding the patent to expiration.

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Timeline diagram

timeline
    title Ownership of US 6626072
    1999 : Provisional filed 07 Jul
    2000 : Application filed 07 Jun
         : Assignment recorded to Logan Clutch
    2003 : Patent issued 30 Sep
    2004 : Certificate of correction
    2015 : 12 year maintenance fee paid
    2020 : Patent expired 01 Jul

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NPE / troll-pattern signals

1. Shell-entity transfer — Not present. No "IP / Patents / Licensing / Holdings / Ventures" entity appears anywhere on the record. The only assignee is Logan Clutch Corporation, a 50-year-old family-owned OEM at a single Cleveland, Ohio manufacturing address (28855 Ranney Pkwy). No registered-agent service address, no single-purpose LLC, and the assignee demonstrably sells clutches and machine-tool controls.

2. Known asserter in the chain — Not present. The chain contains exactly one entity, Logan Clutch Corporation, which matches no entry on the referenced lists (Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities). The only near-miss names in the citation list — US 5,730,037 (Logan Clutch, 1995), US 6,050,162 (Logan Clutch, 1996), US 6,125,982 "Threading clutch for a multi-spindle machine" (Logan Clutch, 1998) — are the assignee's own earlier patents, i.e., a normal prosecution-family citation pattern, not an assertion portfolio.

3. Repeat correspondent across the chain — Unclear. There is only one link, so the "recurrence" test cannot be met by definition. The correspondent name for reel 010870/0413 was not retrievable through the sources I could reach, and I will not invent one. Note also that the three sibling Logan Clutch patents cited above all share the same assignee, so any single recording firm appearing across them would be operating-company counsel, not an NPE-side repeat player.

4. Cascading transfers — Not present. Zero consecutive assignments, let alone multiple within 24 months.

5. Pre-litigation transfer — Not present. No assignment post-dates issuance at all, so no assignment could be timed to a suit. I found no infringement action naming US 6,626,072 in any district court docket or Federal Circuit opinion surfaced by search.

6. Bankruptcy fire-sale — Not present. No Chapter 7/11 filing for Logan Clutch Corporation was found; the entity is currently trading and publishing 2021–2022 product catalogs. A note of caution for the analyst: search results surface a different "Logan" — Logan Industries International (offshore energy, sold to DGI after a Cargotec confidentiality dispute, Texas Supreme Court No. 19-0354) — and a "Logan" oilfield business. These are unrelated entities and must not be conflated with Logan Clutch Corporation.

7. Privateering — Not present. No transfer of this patent to any third party, so no opportunity for the operating company to assert through a proxy.

8. Defensive aggregator (anti-NPE) — Not present. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN. This is a straightforward "original assignee retained ownership to expiry" pattern, not a neutralization.

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Verdict

Insufficient data — under the rubric's own definition ("no records, or only the original assignment"). The entire recorded chain is one link: inventors Kalinsky and Stevens → Logan Clutch Corporation, executed 2000-04-07 and recorded 2000-06-07 at reel 010870/0413. There is no post-issuance transfer, no security interest, no license record, no litigation, and no bankruptcy — the patent simply ran to its 2020-07-01 expiration in the hands of its original operating-company owner, which is a genuine clutch and machine-tool-control OEM in Cleveland, Ohio that paid its 4-, 8-, and 12-year maintenance fees (2007-02-19, 2011-01-21, 2015-02-14) and kept filing related applications into 2015–2018. On the substantive question, the practical read is unambiguous: no NPE or troll signal exists in this chain — the classification "Insufficient data" reflects only that a one-link chain gives an NPE-pattern screen nothing to test, not any residual suspicion about Logan.

Verification links:

• USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (search patent 6626072 — reel 010870/0413)
• Legacy USPTO assignment index: https://assignment.uspto.gov/patent/index.html
• Google Patents legal events used above: https://patents.google.com/patent/US6626072/en
• Assignee portfolio (context): https://patents.justia.com/assignee/logan-clutch-corporation

Two things I could not confirm and am flagging rather than filling in: (a) the correspondent/attorney of record on reel 010870/0413, which the Assignment Center will show directly and which no mirror I reached exposes; and (b) whether any specific Logan product SKU reads on claim 1 verbatim.

I'll search for the patent and its cited prior art.

Let me verify the most relevant cited references (the same-assignee Logan Clutch patents and a few others).

Prior-Art Analysis — US Patent No. 6,626,072 B1

1. Patent Under Review (verbatim identifiers)

Sources: https://patents.google.com/patent/US6626072/en ; https://patentimages.storage.googleapis.com/0b/27/04/360a8e806d85d5/US6626072.pdf ; https://patents.justia.com/patent/6626072

The invention's core is a control scheme in which each of two (or more) machining/threading tools has its own detector (e.g., limit switch + switch actuator), and a controller determines the "earlier" of the two tools to reach its selected (full-stroke) position; that tool's machining clutch is disengaged so it idles, and when the later tool finishes, both clutches are re-engaged and the high-speed clutch is engaged to withdraw and index. Independent claims 1 and 14 are the broadest (two detectors + controller determining the earlier tool); claim 4 adds machining clutches; claim 9 adds high/low speed clutches; claims 15–20 are the method counterpart.

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2. Cited Prior Art — Full List (11 U.S. patent citations, all "cited by examiner")

Source: Citations table at https://patents.google.com/patent/US6626072/en (Citations / Patent Citations sections).

All eleven are U.S. patents cited by the examiner. Since US 6,626,072 was filed 2000-06-07 (pre-AIA regime), references published before 1998-07-07 are available as §102(b) statutory bars; U.S. patents with earlier effective filing dates are additionally available under §102(e).

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3. Reference-by-Reference Analysis

Important framing: Anticipation under 35 U.S.C. §102 requires that a single reference disclose every element of a claim as arranged in the claim. No cited reference, on the record available, discloses the claimed "controller … operative to determine the earlier of the first or second machining tool reaching its selected position" with two independent tool detectors. That determination is the point of novelty. Accordingly, my assessment below identifies claims each reference could potentially reach under §102, but in most cases the reference is more realistically §103 (obviousness) material or background art. Where I lack full text, I say so.

3.1 US4267495A — "Machine speed controller" (Cone-Blanchard Machine Company)

• Dates: priority 1979-10-05; published 1981-05-12. §102(b) prior art (published >1 year before the 1999-07-07 priority date).
• Description: A controller for governing machine speed; directly pertinent to the high-speed/low-speed shifting architecture that the patent's claim 8/20 recite. The examiner's use of this reference is consistent with treating high/low speed control as old.
• Potentially anticipates: Elements of claims 8 and 20 (high speed clutch / low speed clutch selectively engaging a motor to high- and low-speed drive trains). Alone, it does not reach independent claims 1, 4, 9, 14, or 15, because it lacks any plural-tool "earlier/later" logic. Not a standalone anticipation of any claim in my assessment — likely §103 with another reference.

3.2 US4499792A — "Apparatus for angularly positioning a rotary member" (K.K. Komatsu Seisakusho)

• Dates: priority 1982-06-22; published 1985-02-19. §102(b).
• Description: Positioning/angular orientation of a rotary member — i.e., controlled indexing of a rotating carrier, the "main drum may index" step the patent claims.
• Potentially anticipates: Potentially supportive of the "indexing the multiple spindle machine" step in claim 15 and the index step in claim 9, and of the general position-detection environment. Does not disclose two tool detectors or the earlier/later determination; no anticipation of claim 1, 4, 9, 14, or 15.

3.3 US4604560A — "Numerical control machine tool with an emergency origin returning function" (Toyoda Koki K.K.)

• Dates: priority 1982-10-13; published 1986-08-05. §102(b).
• Description: NC machine tool that returns to an origin/reference position — relevant to the position-detection aspect (detector/limit switch reporting that a tool has reached a selected position).
• Potentially anticipates: The "first detector … operative to detect the first machining tool reaching a selected position" element of claims 1, 4, 9, 14. Standing alone it does not disclose a second detector or the earlier/later determination, so it cannot anticipate any full claim. Best characterized as §102(a)/(b) background art.

3.4 US4655652A — "Method of multiple station drilling" (The O.S. Kelly Company)

• Dates: priority 1982-02-03; published 1987-04-07. §102(b).
• Description: Multiple-station, simultaneous machining (drilling) of workpieces — the same "all stations produce parts simultaneously" environment recited throughout US 6,626,072. This is the closest of the non-Logan references to the plural-machining environment.
• Potentially anticipates: The plural-station/multiple-tool preamble of claims 1, 4, 9, 14, 15. It does not, on the available text, disclose per-tool detectors tied to a controller that resolves which tool finished first; no anticipation of any independent claim as a whole. Realistically §103 context for the "plural tool" concept.

3.5 US5027680A — "Machine tool with two spindles" (Fanuc Ltd.)

• Dates: priority 1988-03-09; published 1991-07-02. §102(b).
• Description: A machine tool with two spindles — structurally analogous to the patent's two simultaneously operated work stations/tools.
• Potentially anticipates: Confirms two-tool/two-spindle machine tools are old (relevant to claims 1, 4, 14, 15 preambles). It does not disclose the claimed two-detector + earlier-tool controller logic; no anticipation of a full claim.

3.6 US5197363A — "Spindle driving device for a machine tool" (Mitsubishi Denki K.K.)

• Dates: priority 1989-06-15; published 1993-03-30. §102(b).
• Description: Spindle drive/driving arrangement for machine tools; cited for the drive-train/engagement aspects. Note it is, in turn, cited by the examiner as a document citing US 6,626,072 (per Google's "Cited By" list).
• Potentially anticipates: Attributes of spindle driving and engagement; no disclosure of the earlier/later-tool determination. Not an anticipatory reference for any claim; background §102(b) art.

3.7 US5313861A — "Workpiece exchanging system" (Fanuc Ltd.)

• Dates: priority 1989-12-15; published 1994-05-24. §102(b).
• Description: Automated workpiece handling/exchange — relevant to indexing/handling of workpieces between stations.
• Potentially anticipates: At most, the indexing/workpiece-transfer aspects underlying the "index … to its next position" language in claims 9 and 15. No two-detector/earlier-tool teaching; no anticipation.

3.8 US5730037A — "Multi-spindle machine control systems" (Logan Clutch Corporation) — same assignee

• Dates: filed 1995-04-17 (Ser. No. 08/423,238); published 1998-03-24. §102(b) (published >1 yr before priority) and §102(e) (U.S. patent, earlier filing).
• Description (from the reference): A multi-spindle machine with a dedicated programmable controller; a processor in operative connection with a plurality of sensors; high- and low-speed clutch pair in operative connection with the controller and shiftable high↔low speed under controller control; a timing shaft/encoder for position; display and administrative workstation. It expressly discusses the high/low speed cycle and the risk of indexing damage. See https://patents.google.com/patent/[US5730037](/patent/US5730037) and https://patentimages.storage.googleapis.com/6a/f2/ec/4e3d986c3854d3/US5730037.pdf
• Potentially anticipates: Most relevant to claim 9's controller-in-connection-with-high/low-speed-clutch architecture and to the "controller … in operative connection with … detectors" concept in claims 1/4. However, US 5,730,037 is a machine control/monitoring system (sensors for fault detection, shift-point optimization, data capture) rather than a system that determines which of two machining tools reached depth first. On the available text, it does not anticipate claims 1, 4, 9, 14, or 15. Because it is commonly owned, it also raises the pre-AIA §103(c) common-ownership consideration if relied upon for obviousness.

3.9 US5808893A — "System for adapting an automatic screw machine to achieve computer numeric control" (Amt Machine Systems, Ltd.)

• Dates: filed 1993-07-28; published 1998-09-15. §102(e) (U.S. patent, earlier filing).
• Description: Retrofitting an automatic screw machine for CNC control — relevant to the patent's stated objective of being retrofittable to existing multiple spindle machines and to controller-driven tool sequencing.
• Potentially anticipates: Generic controller/CAM sequencing environment. Not shown to disclose two independent tool detectors plus the earlier-tool determination; no anticipation of any claim. §102(e) art, best used under §103.

3.10 US6050162A — "Multi-spindle machine retrofit system" (Logan Clutch Corporation) — same assignee

• Dates: priority listed 1996-06-07; published 2000-04-18 (application Ser. No. 08/871,019, filed 1997-06-06). Available as §102(e) art (effective filing before applicant's filing); because it is commonly owned, it may be disqualified as prior art for obviousness under pre-AIA §103(c), though it remains a §102 reference.
• Description: A retrofit system with a high speed clutch, a feed clutch, and a brake clutch in the drive-train layout, electrically controlled/pneumatically actuated; a controller receiving manual inputs and sending signals to solenoid valves; a timer; and a limit switch sensing the rotational position of the timing shaft. Claims recite controller-driven engagement/disengagement of high speed and feed clutches with the brake clutch engaged during high→low transitions. See https://patents.justia.com/patent/[6050162](/patent/6050162)
• Potentially anticipates: Elements of claims 8 and 20 (high speed clutch / low speed drive train engagement-disengagement) and the controller/solenoid/timer control plumbing inherent to claim 9's controller. It does not disclose two tool detectors or the earlier/later-tool determination, so it does not anticipate independent claims 1, 4, 9, 14, or 15.

3.11 US6125982A — "Threading clutch for a multi-spindle machine" (Logan Clutch Corporation) — same assignee

• Dates: filed 1998-06-09; published 2000-10-03. §102(e) art (effective filing before applicant's filing); commonly owned (see §103(c) note above).
• Description: A pneumatically actuated, electronically controlled threading clutch with a high-speed side and a low-speed side; a limit switch in electrical communication with the control circuit and operatively connected to a threading tool (112); a count-down timer started when the limit switch is tripped to energize a solenoid valve that shifts the threading clutch from low speed to high speed; varying static torque capacity via pressure control; electronically monitored tap depth. This is the most technically proximate reference, and the closest thing in the cited set to the patent's hardware. See https://FreePatentsOnline.com/[6125982](/patent/6125982).html and https://patents.justia.com/assignee/logan-clutch-corporation
• Potentially anticipates: The limit-switch/actuator detection of claims 6, 7, 10–13, 18, 19; the threading (machining) clutch of claims 4 and 16; and the low-speed-tap / high-speed-withdraw sequence underlying claims 8 and 20. However, US 6,125,982 describes one threading tool with one limit switch and a timer — not two detectors and a controller that resolves the earlier of two tools and idles it. It therefore does not anticipate claims 1, 2, 3, 4 (as a whole), 9, 14, or 15. Its most likely role is as §103 art combined with a two-station/multi-tool teaching (e.g., US 4,655,652 or US 5,027,680).

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4. Overall Conclusions

1. Confirmed patent identity. The number 6626072 / US 6,626,072 B1 corresponds to "Multiple spindle machine plural threading apparatus and method," Logan Clutch Corp., filed 2000-06-07 on application US 09/589,988, granted 2003-09-30.

2. No single cited reference appears to anticipate the independent claims. Claims 1 and 14 (and their method counterpart 15) turn on a controller that determines which of two tools reached its selected position first — a determination none of the eleven cited references is shown to disclose. Claims 4 and 9 add machining clutches and high/low speed clutches, again without the earlier/later-tool decision being shown in any one reference.

3. The cited references are predominantly background or §103-combination material:

   • High/low speed clutch control: US 4,267,495; US 6,050,162; US 6,125,982; US 5,730,037.
   • Plural/multiple station simultaneous machining: US 4,655,652; US 5,027,680.
   • Indexing / workpiece transfer: US 4,499,792; US 5,313,861.
   • Position detection / NC positioning: US 4,604,560; US 5,807,893.
   • Spindle drive: US 5,197,363.

4. Closest art. US 6,125,982 A (Logan Clutch) is the most proximate single reference — it supplies the threading clutch, limit-switch trip, timer, and low→high speed shift — but it is a single-tool system, so it cannot anticipate the two-detector/earlier-tool claims. US 5,730,037 (Logan Clutch) supplies the multi-spindle controller and high/low speed clutch architecture.

5. Common-ownership caveat (§103(c)). Four references — US 5,730,037, US 6,050,162, US 6,125,982 (all Logan Clutch Corp.), and the applicant's own predecessor work — share the assignee of US 6,626,072. Under pre-AIA §103(c), subject matter that qualifies as prior art only under §102(e)/(f)/(g) and was commonly owned at the time of invention is disqualified as prior art for obviousness. This does not remove them as §102 anticipation references, but it materially weakens any §103 attack built on them.

6. Related later art (for completeness, not examiner-cited against 6,626,072). US 10,160,038 B1 (Logan Clutch, granted 2018-12-25) is listed among similar documents and reflects the same assignee's continuing work on multi-spindle machine control. It is not prior art to US 6,626,072.

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5. Caveats and Limitations

• I have the citation metadata (number, dates, assignee, title) directly from the patent's own citation table, which is authoritative. For references 1–9 I do not have the full text in this session, so my statements about what each does/does not disclose are based on the title, assignee, and the examiner's citation pattern; the §102 "potential anticipation" designations for those nine are therefore preliminary.
• The anticipation judgments stated here are analyst opinions, not legal conclusions. Actual anticipation requires element-by-element comparison against the full specification and claims of each reference, which should be performed against the complete documents.
• All numeric identifiers are reproduced literally as they appear in the sources; no identifiers have been auto-corrected.

Primary sources cited: https://patents.google.com/patent/US6626072/en ; https://patentimages.storage.googleapis.com/0b/27/04/360a8e806d85d5/US6626072.pdf ; https://patents.justia.com/patent/6626072 ; https://patents.google.com/patent/US5730037 ; https://patents.justia.com/patent/6050162 ; https://FreePatentsOnline.com/6125982.html ; https://loganclutch.com/patents-and-trademarks

I'll ground this analysis in the actual cited prior art. Let me pull details on the most relevant references.

Obviousness Analysis — U.S. Patent No. 6,626,072

"Multiple spindle machine plural threading apparatus and method" — 35 U.S.C. § 103

Built on the previously generated summary and litigation sections. Bibliographic data, the five independent claims (1, 4, 9, 14, 15) and their dependents, and the "no litigation found" finding are taken as given and not repeated here. This section addresses validity under § 103 only.

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0. Framework and evidentiary posture

I apply Graham v. John Deere (scope/content of prior art; differences; PHOSITA level; objective indicia) with the KSR Int'l v. Teleflex (2007) rationales and MPEP § 2143. The relevant rationales here are:

• (A) Combining prior art elements according to known methods to yield predictable results ("predictable use of prior art elements according to their established functions").
• (C) Design incentives / market forces (the field openly recognized the synchronization problem).
• (D)/(B) Obvious substitution of one known element for another (servo motor for clutch) and obvious duplication of parts (a second detector).

Critical evidentiary baseline: the '072 specification itself concedes the problem and much of the environment. It admits the prior art already used a single limit switch (32) shared by both threading tools; that the operator must hand-tune the actuator (30) so both tools finish together; that electromagnetic clutches gave insufficient torque; that pneumatic clutches gave torque but poor synchronizability; and that the machine shifts between high and low speed via high/low speed clutches. These admissions shrink the gap the claims must bridge — the only genuinely new subject matter is per-tool detection plus controller arbitration of "the earlier" tool, and idling it while the later tool finishes.

My analysis rests on the reference abstracts, claims, and specification passages retrieved below, not on a full figure-by-figure parsing of every reference. That limitation is material to the caveats in § 7.

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1. Level of ordinary skill (PHOSITA)

A person with a B.S. in mechanical or electrical engineering (or equivalent practical training) and roughly 2–5 years' experience designing or setting up multi-spindle screw machines and their clutch/control systems — or a senior machine-tool set-up technician who is conversant with programmable controllers, limit switches, encoders, pneumatic clutches, and high/low-speed drive trains. The art is a mature, crowded mechanical-control field; the PHOSITA is highly familiar with (i) single main-motor machines driving all stations simultaneously, (ii) clutch-based high/low speed shifting, (iii) cam/timing-shaft coordination, and (iv) limit-switch/encoder position sensing feeding a controller.

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2. The cited prior art — disclosure map

All eleven references below are on the face of '072 as "cited by examiner" (source: https://patents.google.com/patent/[US6626072](/patent/US6626072)/en).

Also relevant as admitted prior-art practice (from the assignee's own product literature describing the same clutch families): "Change of speed is accomplished by a limit switch and a solenoid activated, directional control valve. At the prescribed depth, the limit switch is tripped by the threading slide shaft, shifting the Low-speed clutch to the High-speed clutch, allowing the tap to back out. Slow speed for tapping; Fast speed to back out." (https://loganclutch.com/air-threading-wickman). And the CS2001 control's "Thread Check" feature "detects when the tap has cut to full depth" and "determines whether the tapping cycle is complete before high-point," shutting the machine down if not (https://loganclutch.com/cs2001-clutch-saver). These admissions are highly probative of what the field already knew.

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3. Claim-by-claim obviousness analysis

3.1 Claims 1 and 14 (broadest: two detectors + controller determines "the earlier")

Elements: first detector (tool 1 position) + second detector (tool 2 position) + controller connected to both + controller operative to determine the earlier of the two.

Proposed combination: US 6,125,982 + US 5,738,037 (optionally + US 4,655,652 / US 5,027,680).

• '982 discloses a limit switch operatively connected to a threading tool feeding an electronic control circuit — i.e., a per-tool detector plus a controller.
• '037 discloses a programmable controller in operative communication with a plurality of sensors on a multi-spindle machine, programmed to act on sensor signals (it even recites plural tools driven by drive shafts and a high/low clutch pair).
• '652 and '680 confirm that plural machining tools/stations operating simultaneously under electronic control was routine.

Differences: The claim requires the sensors to be per-tool and the controller to identify which tool reached its threshold first. The prior art (as the '072 background admits) used one limit switch for both tools. The delta is therefore: (a) duplicate the detector; (b) compare two signals.

Motivation / rationale (KSR (A), (C), (D)):

1. Duplication of a known element — the field already sensed one threading tool's depth with a limit switch ('982). Extending that sensing to the second, identical tool at the second, identical station is the paradigm "duplication of parts" that KSR treats as an engineering design choice, not invention.
2. Known problem in the field — the '072 specification confesses the single-switch approach required manual tuning so both tools finished together, and that a malfunction was a known risk ('037 itself notes the risk of indexing with a mechanism faulted). Adding a second sensor to eliminate the manual-tuning step is directly responsive to a recognized deficiency.
3. The arbitration logic adds no structure — "determine the earlier" is a comparison of two logic signals, indistinguishable from routine controller programming in a controller ('037) already capable of multi-sensor logic. KSR teaches that "a court must ask whether the improvement is more than the predictable use of prior art elements according to their established functions." A comparator is precisely that.

Assessment: Claims 1 and 14 are the most vulnerable to § 103. The claims are drafted at the level of a detection-and-comparison function and recite no clutch, no idle, no re-engage, no high/low shift — leaving them exposed to a straightforward per-tool-sensor + programmable-controller rationale. If I were drafting a rejection, this is where I would lead.

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3.2 Claim 4 (adds machining clutches; disengage earlier, hold until later, then re-engage both)

Elements: claims 1's structure plus first/second machining clutches as the selective engagement devices; controller disengages the earlier tool's clutch; holds until the later tool reaches position; then re-engages both so both tools may retract and the machine may index.

Proposed combination: US 6,125,982 + US 6,050,162 + US 5,738,037.

• '982 supplies the threading clutch as the engagement device and its electronic control responsive to a tool-depth limit switch — literally "a machining clutch selectively operative to engage and disengage a machining tool … controlled by an electrical circuit responsive to a limit switch."
• '162 supplies plural clutches under a single electrical control system with a controller and timer — establishing that multi-clutch, controller-coordinated engagement is routine in this exact machine family.
• '037 supplies the programmable controller that can hold a state and act on later signals.

Differences: the hold-the-earlier-tool-idle-until-the-later-tool-finishes-and-then-re-engage sequence.

Motivation / rationale:

1. The machine cycle forces a decision. Because the drum can only index after all tools clear the work ("Threading operations must be started and finished generally simultaneously … for the drum to index" — '072 background; echoed by '037's concern about indexing with a faulted mechanism), the designer confronting an earlier-finishing tool has only two options: retract it, or park/idle it. Retracting an engaged tap mid-cut is exactly the failure mode the art warned against; idling by disengaging the clutch is the natural, safer choice and uses the clutch for its established function (engaging/disengaging).
2. Clutches exist precisely to engage/disengage ('982, '162). Using one to idle a tool is not the discovery of a new capability; it is the known capability applied to a recognized need.
3. Re-engaging before a common high-speed withdrawal mirrors the art's own "slow speed to tap, fast speed to back out" ('982; Logan literature). Coordinating two such clutches under one controller ('162) is a predictable arrangement.

Assessment: Moderate-to-strong obviousness. The functional result ("idle the earlier tool") is a predictable extension of the known clutch's disengage function, driven by a recognized cycle constraint. The principal counterargument is that no cited reference expressly teaches arbitration of "the earlier" tool combined with idling — the defense would stress that the prior art forced simultaneous completion rather than idle-and-wait. See § 6.

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3.3 Claim 9 (full plural-machining clutch apparatus with high/low speed clutches)

Elements: motor; power drive train drivable low or high; main drum shaft; high speed clutch; low speed clutch; first/second machining clutches; first/second detectors; a controller connected to all six; and the operation: earlier tool disengaged until later reaches position, whereupon low-speed clutch disengages, high-speed clutch engages, both machining clutches engage, tools retract, machine indexes.

Proposed combination: US 6,050,162 + US 6,125,982 + US 5,738,037 (optionally + US 4,267,495 for speed control).

This is the strongest combination for the challenger, because the machine environment is almost verbatim in '162:

• '162 recites the motor, power feed train (low/high), main drum shaft, high speed clutch, feed clutch, brake clutch, electrical control system with controller and timer, limit switch, and encoder. Every environmental element of claim 9 is disclosed.
• '982 recites the machining (threading) clutch and the limit switch responsive to threading-tool depth — supplying the two "machining clutches" and two "detectors."
• '037 recites the controller interfaced with plural sensors and with the high/low clutch pair, and (claim 17 thereof) a clutch pair that "changes the speed of said drive shaft from a high speed to a relatively low speed and vice-versa" under controller control.

Differences: only the two-tool arbitration/idle-and-wait overlay, plus placement of the machining clutches at two stations.

Motivation / rationale (KSR (A) + (C)):

• Combining '162's drive-train/clutch architecture with '982's threading clutch and '037's multi-sensor controller yields a system whose every recited component is known and whose interconnection (clutches and sensor → controller) is standard. The result is "the predictable use of prior art elements according to their established functions."
• The low-speed-tap / high-speed-withdraw sequence is expressly known ('982: "shifting the Low-speed clutch to the High-speed clutch, allowing the tap to back out"), so claim 9's retract sequence adds no new mechanism.

Assessment: Strong. Claim 9 is essentially a system integration of '162 + '982 + '037; the only meaningful inventive contribution is the arbitration logic, which overlaps the § 3.1 analysis.

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3.4 Claim 15 (full-cycle method)

Elements: detect both tool positions; determine earlier; disengage earlier tool's engagement device; determine later tool reached position; re-engage earlier tool's device; retract; index.

Proposed combination: identical to § 3.2/'982 + '162 + '037, framed as method steps.

Motivation: The method is the operational counterpart of claim 4/9. A method claim that recites acting on the outputs of known sensors and known clutches is obvious for the same reasons, and under KSR the recitation of a known device's necessary operating steps does not impart patentability. Because the underlying apparatus elements are known, the method reduces to "detect → compare → disengage → wait → re-engage → index," i.e., the inherent operating sequence of the combined apparatus.

Assessment: Moderate-to-strong, tracking claims 4 and 9.

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3.5 Claims 5 and 17 (servo motors as the engagement devices)

Proposed combination: US 5,808,893 + US 6,125,982 + US 6,050,162 (optionally US 5,197,363 / US 5,027,680).

• '893 expressly replaces a mechanical cam actuator with a servo actuator whose position is controller-governed via a trajectory and encoder feedback — i.e., a servo performs a tool's engagement/disengagement motion under programmable control.
• '363 and '680 disclose motor-driven spindle arrangements in multi-tool/machine-tool settings.
• '982/'162 establish that the selective engagement device for a threading station is a clutch that is engaged/disengaged by a controller.

Rationale (KSR (D) — obvious substitution): Swapping a clutch for a servo motor as the selective engagement/disengagement device is the substitution of one known engagement mechanism for another, both known in the field, with predictable results (the '072 specification itself frames the servo as an alternative to the clutch, and even notes the servo may be de-energized to let the tool free-wheel or driven at spindle speed — both predictable modes). '893 confirms the servo-with-controller is known and readily integrated.

Assessment: Strong on the substitution rationale; the specific "de-energize to free-wheel / rotate at spindle speed" alternatives are predictable operational modes of a servo.

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3.6 Claims 6–7 and 10–13, 18–19 (limit switches + switch actuators as the detectors)

Directly anticipated/disclosed in substance by US 6,125,982, which claims a "switch positioned adjacent the threading slide for engagement at a selected distance as the threading slide moves toward a work piece" and a control circuit in electrical communication with that switch. Claims 6/7 (limit switch engaging a switch actuator attached to the tool) and 10–13/18–19 (signal to controller on switch engagement) are the ordinary hardware implementation of '982's switch-plus-circuit, and are also conventional in '162 (limit switch + encoder). Assessment: Strongly obvious — these dependents add no inventive weight independent of their parents.

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3.7 Claims 8 and 20 (disengage low-speed clutch, engage high-speed clutch for retract)

Directly disclosed by US 6,125,982 ("shifting the Low-speed clutch to the High-speed clutch, allowing the tap to back out"; "the shifting means … to a high speed side … to withdraw the tap"), reinforced by US 4,267,495 (machine speed controller) and US 6,050,162 (high speed clutch + feed clutch + brake clutch under a controller/timer). Assessment: Strongly obvious; this is admitted prior-art practice.

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4. Summary claim chart

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5. Why a PHOSITA would have been motivated to combine (consolidated)

1. Same field, same problem, same machine family. Ten of the eleven references are machine-tool/CNC references; three ('737, '162, '982) are the same assignee's own multi-spindle clutch/control patents, expressly cross-referenced as incorporated-by-reference companions. Combining them is not hindsight — the assignee's own patents already cross-cite one another.
2. Recognized problem with a known deficiency. The specification concedes the single-switch, hand-tuned approach and the torque/synchronization limits of the prior clutches. Under KSR, "a problem in the art that the inventor sought to solve" is itself a motivation source.
3. Design incentive / market forces (KSR (C)). The field was actively optimizing cycle time and reducing setup/scrap (see '982's stated ~0.8s → ~0.6s cycle goal and '037's productivity aims), which supplies a concrete incentive to eliminate manual synchronization.
4. Predictable results. Every element (detector, clutch, controller, high/low drive, servo) performs its known function; the combination yields the expected aggregate behavior (coordinate two stations, index safely).
5. Obvious-to-try (KSR (F)). Facing two parallel threading operations that must both complete before indexing, a finite, small set of known control strategies exists (sense each tool; either re-time or idle-and-wait). The claimed approach is one of them.

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6. Arguments that could preserve validity (defense side)

To be balanced, these are the credible rebuttals:

• No express teaching of "the earlier." None of the cited references appears to explicitly teach arbitrating which of two tools finished first, nor idling the earlier tool. A patentee would argue the art instead taught away by insisting operations complete simultaneously and by explicitly warning (per the '072 background) that a second completion signal "could" cause unintended operation — arguably a teaching away from per-tool signaling.
• The "second switch is redundant / dangerous" statement. The specification explains why the prior art deliberately used one switch ("Use of a second limit switch … would be redundant … unintended operation could occur if a second actuator and switch … sent a completion signal rather than the first"). If a reference genuinely disparages the second detector, that is potential teaching away — though "redundant" is a weak basis for teaching away because it is a statement about expected correctness, not a physical impossibility.
• Functional-result vs. structure. Claims 4/9/15 recite a specific free-wheel/hold/re-engage sequence with a high-speed simultaneous withdrawal; a patentee could argue this is a non-obvious coordination algorithm rather than a mere automation of known steps.
• Objective indicia (§ 6 below).

These are genuine but, in my view, insufficient on the record to overcome the § 3.1–3.7 rationales for the apparatus and system claims, because the "teaching away" evidence arises from the patent's own description of the prior art rather than from an independent reference, and because the second-detector duplication is, at bottom, a design choice.

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7. Objective indicia (secondary considerations)

The '072 specification asserts: sufficient torque for plural machining; tools idle until the last finishes; reduced need for precise settings / reduced setup time; reduced stock waste during setup; retrofit capability. Assessing nexus (each to the claimed invention, not to unclaimed features):

• Torque (~50% gain vs. electromagnetic clutches): The specification attributes this to using pneumatic clutches. Pneumatic threading clutches with pressure-controlled torque are already disclosed in '982 and '162. Weak nexus — the benefit flows from an unclaimed/known component choice, not from the arbitration logic.
• Idling until the last tool finishes / reduced setup precision / reduced scrap: These do flow from the claimed arbitration. This is the patentee's best secondary-consideration argument, provided the nexus is proven with data (the record I have shows assertions, not comparative test data).
• Retrofit capability: Already disclosed by '162 (retrofit system). No nexus to the new subject matter.

I found no evidence in the record of commercial success, copying, licensing, or industry praise attributable to the claimed arbitration (consistent with the previously generated "no litigation found" conclusion — the patent expired 2020-07-01, its full enforceable term 2003–2020).

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8. Overall conclusion

• Claims 1 and 14 are the most likely to be invalidated under § 103 over '982 in view of '037 (optionally with '652/'680): the claims cover per-tool detection plus a controller comparison, and adding a second detector and comparing two signals is a predictable design choice solving an admitted prior-art problem.
• Claim 9 (and, by extension, the method of claim 15) is strongly vulnerable over '162 + '982 + '037, because '162 supplies the entire recited machine/drive-train environment and '982 supplies the threading clutch + tool-depth switch, leaving only the arbitration logic as the point of novelty.
• Claims 4 and 15 present the closest call: the specific idle-the-earlier-tool-until-the-later-finishes-and-then-re-engage sequence is not expressly disclosed in the cited art, but is a predictable application of a clutch's known disengage function driven by the machine's indexing constraint.
• Dependent claims 5–8, 10–13, 16–20 add essentially no independent inventive weight: the limit-switch/actuator structure is disclosed by '982; the servo alternative is an obvious substitution supported by '893; and the low-speed→high-speed withdrawal is admitted prior-art practice.

Bottom line: On the cited-art record, the broadest claims (1, 9, 14) and most dependents appear obvious under KSR, with the strength of the case declining, but not disappearing, for the specific cycle-coordination claims (4, 15) and the servo claims (5, 17).

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9. Caveats and limits of this analysis

1. Partial reference parsing. I worked from retrieved abstracts, claim sets, and specification excerpts (Google Patents, FreePatentsOnline, Justia, and the assignee's site) — not from a full text/figure review of each of the eleven cited references, particularly the older mechanical references ('495, '792, '560, '652, '680, '363, '861), whose exact disclosures I characterize only at a high level.
2. Certificate of correction (recorded 2004-03-02). Its contents are not available to me; if it altered claim text or dependencies, the mapping above should be re-verified against the corrected printed claims. This is flagged in the earlier summary section as well.
3. Dependency oddity noted earlier (claim 5 depending from claim 3 while introducing servo motors; claim 8 depending from claim 4) is carried forward and could interact with a correction.
4. Teaching-away is arguable. The specification's own statement that a second switch "would be redundant" and could cause "unintended operation" is the strongest defense, but it is the patent's characterization of the prior art, not an independent reference's disparagement, which weakens its force under current Federal Circuit law.
5. This is an analytic assessment, not a legal opinion or an invalidity determination. A definitive § 103 conclusion would require the full prosecution history, the corrected claims, and complete reference texts.

Sources: https://patents.google.com/patent/US6626072/en · https://patents.google.com/patent/US5730037 · https://patents.google.com/patent/US5808893 · https://www.freepatentsonline.com/6125982.html · https://patents.justia.com/patent/6050162 · https://loganclutch.com/air-threading-wickman · https://loganclutch.com/cs2001-clutch-saver