US 4693068

I'll search for authoritative information on this specific patent number before summarizing.

US Patent 4,693,068 — Summary

Note on sourcing: The authoritative full text supplied in the prompt (from https://patents.google.com/patent/[US4693068](/patent/US4693068)/en) is my primary source. My searches also returned the Justia mirror of the same document (https://patents.justia.com/patent/4693068). I was unable to retrieve anything from the USPTO Patent Public Search/Patent Center or from CAFC 2026 dockets — see "Litigation / Docket Check" below.

Bibliographic data

Abstract (verbatim)

"Device for regulating the tension of a thread through the different transformation operations to which said thread is subjected during its manufacture, said device being of the type forming an assembly comprising cups between which passes the thread, said cups being mounted on a hub and locked in position one against the other by way of a nut, and said hub being mounted on a rotary shaft which is common to all the positions of one face of the machine, device wherein: the cups are mounted in pairs on either side of a cylindrical track which is fast in rotation with said cups, said track having a diameter at least equal to the diameter of the circle of contact between the two cups, and said thread being, while thrown, in contact with the central cylindrical track, and after throwing, pushed back onto the side tracks constituted by each pair of cups in order to be placed in the normal working conditions after throwing; and the nuts holding each pair of cups one against the other enable a variation of their pressure, hence an adjustment of the tension which is communicated to the thread."

Claims structure

The patent has 4 claims; only claim 1 is independent. Claims 2–4 depend from it (2→1, 3→2, 4→1).

Independent Claim 1 — plain-language overview

A rotating "slackener" assembly built on one driven shaft, with two yarn-tensioning stations (rather than the prior single station):

• A rotary shaft carries first and second hubs that rotate with it, their inner ends facing each other (juxtaposed).
• A cylindrical track sits at/adjacent those inner ends, encircling the shaft, and is fixedly secured to at least one of the hubs, so it rotates with them.
• Two nuts — one threaded on the outer end of each hub — can be moved axially to change clamping pressure.
• Two pairs of cups straddle the cylindrical track (one pair on each side). Each pair projects radially outward from its hub, ends in free outer ends that form a lateral rim, and is clamped together by its nut to define a side track (a nip through which yarn passes).
• Diameter relationship: the cylindrical track's external diameter is at least equal to the diameter of the first side track and at least equal to the diameter of the second side track.
• Tension adjustment: sliding either nut axially changes cup pressure and therefore the tension imparted to yarn running in that side track.
• Mode of use: during "throwing" (stringing/threading-up), the yarn rides on the central cylindrical track; after throwing it is pushed back onto one of the side tracks for normal running.

This gives two capabilities: running two yarns in parallel (one per side track) or performing two successive slackening/tension adjustments on a single yarn (e.g., before and after a heat-treatment oven).

Dependent claims

• Claim 2 — Central track is a separate part interposed between the two hubs, fastened by a screw, and has two peripheral flanges to retain the yarn during throwing. (This is the FIG. 1 embodiment.)
• Claim 3 — Where the track is that separate part, its external diameter is greater than the diameter of each cup's lateral rim (track protrudes beyond the cups).
• Claim 4 — Alternative: the central track is integrally formed with one of the hubs, and its external diameter is less than the diameter of either lateral rim, so the cup rims retain the yarn and act as a ramp to guide the yarn onto the side tracks after throwing. (This is the FIG. 2 embodiment.)

Litigation / Docket Check

• My searches for CAFC 2026 docket activity involving 4,693,068 returned no results, and no USPTO litigation record surfaced. I cannot confirm a negative from an authoritative docket source (I could not reach Patent Center or the CAFC docket system), so I flag this as unverified rather than conclusive.
• Contextual point (not a substitute for a docket check): the patent lapsed on 1991-09-15 for failure to pay maintenance fees, so it has been unenforceable for over three decades. Any 2026 Federal Circuit appeal involving this patent would be highly unusual.
• Cited-by references in the record include US5345790 (Schouten), GB2325246/US6065711 (Sipra), WO2012174514/US9382645 (American Linc), and CN110735200 — these are later citations, not litigation.

Uncertainty flags

• I did not independently confirm the "I.C. ACBF" assignee name beyond the patent record, and the Google Patents rendering of the current-assignee field is truncated/oddly formatted ("I C ACBF"); the assignment record gives the address as Allée Charles Baron, 26000 Valence, France, effective 1986-06-02.
• All bibliographic values above come from the patent record and Justia mirror; I could not cross-verify against USPTO Patent Center directly.

I'll search litigation-focused sources for this specific patent number.

Initial searches returned irrelevant results (the number matched other records). Let me query litigation-specific databases directly.

Let me try a few more targeted litigation-database searches to confirm the negative.

Litigation Search — US Patent 4,693,068

Bottom line: No litigation involving US Patent 4,693,068 is known. I found no court case, docket entry, PTAB proceeding, ITC action, or reported decision in which this patent was asserted, challenged, or at issue.

Searches run

⚠️ False-positive warning (similar numbers — do NOT attribute to this patent)

Several results mentioned "the '306 patent," but the context shows they are unrelated to US 4,693,068:

• Penda Corp. v. United States / Penda v. U.S. Postal Service (Fed. Cl.) — a thermoformed plastic pallet patent referred to as "the '306 patent," asserted under 28 U.S.C. § 1498 against the Postal Service, with Cadillac Products as third-party defendant; the patent had 17 claims covering a twin-sheet pallet. This is a different patent whose number merely ends in "306."
• The CourtListener "low ball load cell" case (Schreyer v. Casco Products Corp. lineage) — unrelated subject matter.

These are precisely the "similar number" matches you asked me to exclude. They are not litigation on US 4,693,068.

Reasons this negative is credible (not merely "no results")

1. Subject matter. US 4,693,068 is a narrow mechanical textile-machine part ("thread slackening device" / yarn-tensioner for twisting frames) assigned to I.C. ACBF of Valence, France. Such parts are rarely the subject of reported US patent litigation.
2. Legal status. Per the patent record, maintenance-fee reminder mailed 1991-04-16; lapsed for failure to pay maintenance fees 1991-09-15; recorded lapsed 1991-11-19 (and Google Patents shows the patent expired for nonpayment under 37 CFR 1.362). The patent has thus been unenforceable since September 1991 — over 34 years. Asserting an expired-for-nonpayment patent is legally impossible, so any 2026 infringement suit on the US patent would be anomalous.
3. No litigation references in the patent record. The "Cited By" / "Citations" lists on the patent page contain only later patent documents (e.g., US5345790 Schouten; GB2325246/US6065711 Sipra; WO2012174514/US9382645 American Linc; CN110735200) — i.e., citations, not litigation.

Caveats on my search (stated explicitly)

• I could not directly reach the USPTO Patent Center/Patent Public Search, the CAFC docket system, or a PACER/CourtListener docket page for this specific patent; and my tool access terminated before I could run final confirming queries (CourtListener, Docket Alarm, and the Docket Navigator/Unified caselist).
• Accordingly, my conclusion is "no litigation known/found" rather than a certified negative. A definitive negative check would require a paid docket search (Docket Navigator, Lex Machina, or a PACER docket search by patent number) across all federal districts and the Court of Federal Claims, plus a PTAB/CBIP search — none of which I was able to complete here.

Recommended verification (if a certified clear is required): run a patent-number search in Docket Navigator / Lex Machina for 4,693,068, check PTAB for any IPR/PGR on it, and confirm no § 1498 (Court of Federal Claims) action — though given the 1991 lapse, any such hits would be highly surprising.

I'll verify the structured "no proceedings" result against PTAB-specific sources before reporting.

Searches so far returned only an unrelated optical "'068 patent" (IPR2018-01158) and generic IPR primers. Let me run targeted PTAB/CourtListener checks.

Proceedings overview

Zero AIA trial proceedings exist on US 4,693,068 — the USPTO Open Data Portal "PTAB proceedings on file" block for this patent is empty, and my independent searches across the PTAB/P-TACTS public filings, Federal Circuit and CourtListener indexes surfaced no IPR, PGR, or CBM naming this patent or a petitioner/patent-owner pairing involving I.C. ACBF. Because the count is zero, there is no "active / invalidated / sustained / settled / institution-denied" breakdown to give: no claim of this patent has ever been canceled by the Board, and no claim has ever been tested at the Board at all. The defensive posture this creates is unusual and stronger than the usual "untested patent" story: claims 1–4 are untested by the PTAB, but they are also unassertable in the ordinary sense, because the patent lapsed for nonpayment of maintenance fees on 1991-09-15 — roughly 21 years before the first AIA petition could even be filed (AIA trials became available 2012-09-16). There is no petitioner to be estopped, and no FWD to lean on; the defense here is expiration, not invalidation.

Proceedings on file

None. Stated plainly, per the structured ODP block:

"The USPTO ODP API returns no AIA trial proceedings for this patent as of the most recent ingest."

I found nothing to override that default. Per the instruction to flag anything the ODP hasn't indexed, here is what I ran and what came back:

⚠️ False positives to exclude (do NOT attribute to US 4,693,068)

• IPR2018-01158 ("the '068 patent" in the Patent Owner's Notice of Appeal at insight.rpxcorp.com). That proceeding concerns an optical multiplexer / dispersion-compensation '068 patent, with claims 1, 10, 12, and 14 construed and litigated. It is not US 4,693,068 (textile thread slackener), whose claim set is claims 1–4 covering cup pairs on a hub. The number merely shares a suffix.
• EPO Board of Appeal decision T 0807/54 (legacy.epo.org PDF) surfaced in my searches; it concerns a hydraulic wrench / ULC-type tool and a tensioning device (D9). Unrelated to this patent family — and in any event an EPO proceeding, not a PTAB one.
• "ACBF" hits were the African Capacity Building Foundation — a name collision, not the assignee I.C. ACBF of Valence, France.

Why the absence is structural, not merely "no one bothered"

The generic heuristic — "well-asserted patents eventually attract IPRs" — is worth only so much here, and I want to be explicit about why:

1. Timing. US 4,693,068 issued 1987-09-15 and lapsed 1991-09-15. AIA trials did not exist until 2012-09-16. For 21 of the 24 years between issue and the AIA, an IPR was legally impossible. The window in which an AIA petition could have been filed opened long after the patent was dead.
2. No economic incentive. By the time IPRs existed, the patent had been in the public domain for two decades and its enforceability had been over since 1991-09-15 (maintenance-fee reminder mailed 1991-04-16; lapse recorded 1991-11-19). No rational petitioner files an IPR on a patent whose last possible damages accrual closed in 1991.
3. Pre-AIA alternatives were also not used. The record on the patent page shows no ex parte reexamination, no inter partes reexamination (available 1999–2011), and no § 505/§ 146-type proceeding — the "Legal Events" tab lists only the assignment, the maintenance-fee reminder, the lapse, and the 2018 status update under 37 CFR 1.362. So this isn't a case of a pre-AIA challenge hiding outside the AIA-trial filter; there simply is no post-grant challenge of any kind of record.

Strategic summary

Claim status. No claim of US 4,693,068 has been canceled, confirmed, or even instituted upon by the PTAB. All four claims — independent claim 1 and dependent claims 2, 3, and 4 — are untested at the Board. The distinction I want to draw sharply: "untested" here does not mean "hardened." There is no Final Written Decision to cite for or against any claim, and no Board reasoning on the diameter relationships (claim 1's "at least equal to" both side-track diameters; claim 3's "greater than" the lateral rims; claim 4's "less than" the lateral rims) that would be the natural centers of gravity in any validity fight over this patent.

Estoppel landscape. There is no § 315(e)(2) estoppel of any kind, because there is no petitioner and no IPR. No party is barred from raising any prior-art ground, and any defendant today has the full universe of § 102/§ 103 art — including the nine references cited on the face of the patent (US2177039 Houck; US3359716 Deering Milliken; US3525205 Degli Antoni; US3830051 Palitex Project; FR2268884 Bourgeas Fougeirol; FR2430991 Asa; US4237683 Verdol; US4462557 Milliken Research; US4592195 Charbonnier) — available without restriction. In practical terms, however, validity is not the battleground a defendant should be planning for. The controlling facts are:

• The patent expired for nonpayment of maintenance fees on 1991-09-15 (37 CFR 1.362), recorded 1991-11-19. A lapsed patent cannot be infringed by post-lapse conduct. Any demand letter or complaint asserting claims 1–4 against present-day activity is facially defective regardless of what the PTAB has or hasn't done.
• No PTAB proceeding can cure that. A defendant does not need the Board to invalidate claims that were already unenforceable two decades before the Board's IPR jurisdiction existed. The absence of PTAB activity is therefore not a gap in the defensive record — it is a consequence of the patent's own history.

Pattern signals. None to report. There is no repeat petitioner (no petitioner at all), no patent-owner appeal history at the Federal Circuit flowing from a PTAB case, and no defensive aggregator (Unified Patents, RPX, Unified's "Open" programs, etc.) in the chain. The "Cited By" entries on the patent page — US5345790 (Schouten), GB2325246/US6065711 (Sipra), WO2012174514/US9382645 (American Linc), CN110735200 — are later patent documents citing this patent as background art, not proceedings. In particular, the Sipra and American Linc families cite the concept of an overfeed/tensioning assembly; they tell you the technology line survived, not that this patent was ever attacked.

Recommended next steps

If you are a defendant being asserted US 4,693,068:

1. Do not budget for an IPR. Filing an IPR to knock out claims that lapsed in 1991 would be a waste of the filing fee, and the Board would face a threshold question about whether any meaningful estoppel or claim-scope benefit could be obtained on a patent that has been unenforceable since 1991-09-15. There is no FWD to cite, so there is nothing to link to or quote.
2. Lead with the lapse date, not the invalidity case. The dispositive record is in the patent's own Legal Events: maintenance-fee reminder 1991-04-16; lapse for failure to pay 1991-09-15; recorded lapsed 1991-11-19; Google Patents states expiration for nonpayment under 37 CFR 1.362. Assert that the patent's enforceable term ended 1991-09-15, so no accused conduct post-dating that date can infringe claims 1–4. This is a dispositive-lapse / failure-to-state-a-claim posture, not an invalidity posture.
3. If the assertion concerns pre-1991 conduct (extraordinarily unlikely, and time-barred in any event under 35 U.S.C. § 286's six-year damages window), then — and only then — would you need a merits defense. In that hypothetical, no PTAB estoppel constrains you and all nine cited references remain available as § 102/§ 103 art.
4. Verify the clear with a paid docket check before relying on it in a brief. My searches did not reach a dedicated PTAB E2E/P-TACTS docket page or a CourtListener docket for this patent, and I could not obtain a certified negative. Confirm by running a patent-number search for 4,693,068 in PTAB P-TACTS / PTAB E2E (https://ptacts.uspto.gov/) and in CourtListener (https://www.courtlistener.com/) plus the Federal Circuit docket. My conclusion is "no PTAB activity found," not a certified negative.
5. Do not conflate the foreign family with US proceedings. The family includes EP0208628B1, DE3660671D1, FR2583028B1, and ES8705334A1. Those are national/regional counterparts, not PTAB papers — and I did not search for European oppositions at the EPO on EP0208628B1, which is outside the PTAB scope of this task. If your dispute is multi-jurisdictional, that is a separate check.

If a demand letter cites claims 1–4 of US 4,693,068 for current activity: the proceeding record gives you no FWD to brandish, but you do not need one. The patent has been in the public domain since 1991-09-15; any assertion of these claims against post-1991 conduct has a threshold defect independent of the PTAB, and the absence of any IPR — despite more than a decade of AIA-trial availability — is consistent with that reality rather than in tension with it.

I'll verify the assignment record against the USPTO Assignment Center and related sources before reconstructing the chain.

Let me check for any post-issuance assignments and the identity of the recording correspondent.

Ownership Chain Reconstruction — US Patent 4,693,068

Scope note / sourcing limits (stated up front): I could not open assignmentcenter.uspto.gov or assignment.uspto.gov directly with the tools available in this pass (search-only access). The assignment data below is taken from the USPTO assignment record as it is rendered on the patent's own legal-events listing (https://patents.google.com/patent/[US4693068](/patent/US4693068)/en) and cross-checked against the Justia mirror (https://patents.justia.com/patent/4693068) and the assignee index (https://patents.justia.com/assignee/i-c-acbf). That rendering exposes the reel/frame, conveyance type, assignor, assignee, execution date, and recording date, but not the correspondent-of-record (attorney) field — so I cannot make the correspondent-recurrence call this task asks for, and I flag that as an open item rather than a finding. Verify the correspondent by querying the Assignment Center by patent number and opening the full reel/frame image.

Inventors

Single inventor; no joint inventors.

Pattern check — "inventors departing the original assignee within 12 months": NOT PRESENT. This is the inverse case. Matas Gabalda is named as inventor on later patents belonging to the corporate successor, e.g. FR 2 695 631 (ICBT ROANNE as applicant, devising/délivrance 1994–1995) and FR 2 861 095 (RIETER ICBT as depositor, 2003 filing), per the INPI data reproductions surfaced in search (https://data.inpi.fr/export/patents?format=pdf&ids=%5B%22FR2695631%22%5D and ...%5B%22FR2861095%22%5D). He therefore stayed with the Valence/Roanne textile-machinery group for at least ~17 years after filing. There is no inventor-departure/fire-sale precursor signal here; the inventor's career tracks the assignee's succession (ACBF → ICBT → Rieter-ICBT).

Original assignee

• Entity: I.C. ACBF, Allée Charles Baron, 26000 Valence, France (assignment effective date 1986-06-02; recorded 1986-08-06). Google Patents' "current assignee" field renders the same entity truncated as "I C ACBF."

• Primary line of business: Textile machinery — twisting/cabling (retordage) and two-for-one (double-twist) machinery. A 1982 Textile Industries buyer's guide lists "ACBF, S.I. (ARCT, Inc.), B.P. 225, 26002 Valence, France" under Winding/twisting machines and accessories and Texturing machines and accessories. A Valence archives record describes "IC ACBF, fabricant de machines-outils pour l'industrie textile, située zone industrielle des Auréats" (1984) (https://www.memoire-drome.com/recherche-detail.html?p=5076&i=7&id=69433).

• Did they ship a product embodying the claims? Yes — with high confidence. The specification itself (FIGS. 3–4) depicts the claimed slackener installed on the assignee's own two-for-one twisting machine and on a twisting-plus-heat-treatment machine. A tension/slackening device of this kind is a machine accessory, and the claimed "pairs of cups on either side of a central cylindrical track" is exactly what the drawings show fitted to the assignee's frames. This is an operating-company industrial patent, not a paper asset.

• Current status: dissolved / absorbed. The Valence corporate line is well documented in French sources:

  • ACBF reached international prominence, then the ACBF-era operation closed in 1984; the business continued under ICBT (per Progressistes/PCF Drôme-Ardèche and France 3 Régions, both citing "fermer en 1984 … L'entreprise poursuit néanmoins ses activités sous l'étiquette ICBT"; see https://france3-regions.franceinfo.fr/auvergne-rhone-alpes/vallee-du-rhone/drome/valence-verdol-sas-fin-entreprise-centenaire-[1040507](/patent/1040507).html).
  • 2000: ICBT sold to the Swiss Rieter group → renamed Rieter-ICBT.
  • 2006: Rieter exited synthetic-yarn machinery and put the unit up for sale; bought by its managers → RITM.
  • 2010: redressement (judicial reorganization); taken over by the investment fund BavarIA under the name SwissTex.
  • 2012: liquidation judiciaire; assets bought by the Ardèche Reyes group, split into Reyes Intégration (production) and Verdol (R&D).
  • 2015: Verdol patents and drawings sold to a German competitor, reportedly Saurer; headcount down to 19 (France 3 Régions, above).

  Important caveat: this whole succession is documented for the French corporate entities. It does not appear anywhere in the US assignment record for US 4,693,068 (see below) — and it post-dates the US patent's 1991 lapse by up to two decades.

Assignment timeline

The USPTO assignment record for US 4,693,068 contains exactly ONE recorded assignment. That is the pre-issuance, pre-filing inventor-to-company assignment. There are no post-issuance assignments, no change-of-name records, no security interests, and no merger records for this US patent.

• 1986-06-02 (executed) / recorded 1986-08-06 — Reel 004586 / 0326
  • Conveyance: Assignment — "ASSIGNMENT OF ASSIGNORS INTEREST" (per the record text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:MATAS-GABALDA, CARLOS;REEL/FRAME:004586/0326, effective date 19860602)
  • Assignor: MATAS-GABALDA, CARLOS
  • Assignee: I.C. ACBF, Allée Charles Baron, 26000 Valence, France
  • Correspondent: Not exposed in the sources I could retrieve. The rendered record shows only the reel/frame (004586/0326) and no attorney/agent name. I cannot state the recording attorney, and I therefore cannot test the repeat-correspondent signal. For context only (not evidence of the US correspondent): the French patent attorney of record for later same-inventor/successor filings is CABINET LAURENT ET CHARRAS (3 Place de l'Hôtel de Ville, BP 203, 42005 Saint-Étienne / 50 chemin de la Bruyère, 69574 Dardilly), per INPI records — that is a French agent, not a US recording correspondent, and should not be conflated.
  • Context: Standard employee/inventor pre-filing assignment to the operating employer. Executed 1986-06-02, three days before the US application was filed (1986-06-05) and ~15 months before grant (1987-09-15). This is the ordinary "we own what our engineer invented" filing-hygiene step, not a transfer of an issued patent.

Per the task instruction: since the Assignment Center record consists solely of the original assignment, I stop the chain analysis here — but I continue below because the remaining checklist items are answerable as negatives, and the "no further assignments" fact is itself the finding.

Related non-assignment legal events (for completeness, from the same record):

• 1991-04-16 — maintenance-fee reminder mailed
• 1991-09-15 — lapse for failure to pay maintenance fees
• 1991-11-19 — recorded as lapsed (fee-related)
• 2018-01-30 — status note: expired for nonpayment under 37 CFR 1.362

Timeline diagram

timeline
    title Ownership of US 4693068
    1985 : FR priority application filed 11 Jun
    1986 : Inventor assignment executed 2 Jun
         : US application filed 5 Jun
         : Recorded reel 004586 frame 0326
    1987 : US patent issued 15 Sep to I C ACBF
    1991 : Lapsed for unpaid maintenance fee
    2000 : Successor firm ICBT sold to Rieter
    2012 : Successor placed in liquidation

(The 2000 and 2012 rows are corporate-successor context only — no US assignment was ever recorded for this patent, so ownership of the US patent remained with I.C. ACBF on the register until lapse.)

NPE / troll-pattern signals

Supplementary (non-rubric) observation: the decisive event in this patent's life is not an assignment at all — it is the 1991-09-15 lapse for non-payment of maintenance fees (recorded 1991-11-19). That is consistent with a small/mid-size European machinery maker not maintaining a narrow, single-embodiment US mechanical patent through the 1991–1995 fee window. It is an abandonment signal, not an NPE signal.

Verdict

Insufficient data (only the original assignment).

The entire US recorded chain is a single entry: Reel 004586/0326, executed 1986-06-02 and recorded 1986-08-06, conveying inventor Carlos Matas-Gabalda's rights to his employer I.C. ACBF — an assignment executed three days before the 1986-06-05 US filing, i.e. ordinary pre-filing corporate ownership hygiene, not a transfer of an issued patent. No post-issuance assignment, change of name, security interest, or merger was ever recorded against US 4,693,068, so there is no shell-entity, cascading-transfer, or pre-litigation-transfer link to evaluate; the French ACBF→ICBT→Rieter→RITM→SwissTex→Reyes succession and the 2012 liquidation judiciaire / 2015 French patent sale never reached this US register, and the patent itself became unenforceable on 1991-09-15 (lapse for non-payment, recorded 1991-11-19). The only unresolved item is the correspondent of record on Reel 004586/0326, which the sources I could reach do not expose.

Verification links:

• USPTO Patent Assignment Search (search by patent number 4693068): https://assignmentcenter.uspto.gov/ — or https://assignment.uspto.gov/patent/index.html
• Patent record / legal events: https://patents.google.com/patent/US4693068/en
• Assignee index: https://patents.justia.com/assignee/i-c-acbf

Recommended follow-up (to close the one gap): open Reel 004586 / Frame 0326 in the Assignment Center image viewer and transcribe the correspondent attorney/agent and its address; then title-run the same reel for that correspondent's other 1985–1990 recordings. If the correspondent is the US associate of a French conseil en propriété industrielle, that is ordinary foreign-filing practice and not an NPE signal.

I'll search the USPTO database and other sources for US 4,693,068 and each of its cited references.

Let me search the remaining cited references.

Prior-Art Analysis — US 4,693,068 ("Thread slackening device")

Scope note on method and sources. I searched by the exact number 4693068. Results returned the correct document — the Justia mirror (https://patents.justia.com/patent/[4693068](/patent/4693068)) and the Google Patents record — not any of the similarly numbered patents. I could not reach the USPTO Patent Public Search / Patent Center directly with the tools available, and no USPTO-hosted page for this patent was returned. The citation list below is taken verbatim from the authoritative full text supplied in the prompt (the Google Patents "Patent Citations (9)" table, in which an asterisk marks examiner-cited references). For several references I obtained an abstract or full text via search; where I could not retrieve the reference's own text, I say so explicitly rather than inferring disclosure. My tool budget was exhausted before I could pull full texts for FR 2 268 884, FR 2 430 991, US 4,237,683, US 4,462,557 and US 2,177,039.

1. Identification of the patent under analysis

The citations below are the nine references listed on the face of the patent as "Patent Citations (9)", all flagged examiner-cited (*).

2. The nine cited references — summary table

3. Reference-by-reference analysis

3.1 US 2,177,039 A — Houck, "Thread throwing machine and the like"

• Full citation: US 2,177,039 A; filed 1937-03-10; published 1939-10-24; inventor John C. Houck (GoodIP lists 11 applications for this inventor).
• Brief description: A very early silk-throwing/twisting-machine patent. Note the term "throwing" here means silk throwing (i.e., twisting/reeling silk), not the yarn-"throwing" (threading-up) operation discussed in US 4,693,068. It is pre-dated by decades and is a general mechanical thread-machine reference.
• §102 relevance: Does not anticipate any of claims 1–4. It cannot disclose the two juxtaposed hubs, the central cylindrical track fixed to a hub, the two nut-clamped pairs of cups straddling that track, or the reciting diameter relationships of claims 1/3/4. Caveat: I did not retrieve its full text; the conclusion rests on the title, date, and the absence of any indication in the record that it discloses a cup-type slackener.
• Why it appears: Likely cited as the oldest background to the "throwing" terminology.

3.2 US 3,359,716 A — Deering Milliken Research Corp., "Method and apparatus to equalize tension in two or more strands"

• Full citation: US 3,359,716 A; filed 1965-02-23; published 1967-12-26.
• Brief description: Relates to equalizing tension across two or more strands running simultaneously. The related Deering Milliken family art I retrieved (US 2,811,012, "Plying apparatus and method") shows capstan-type strand metering with individual tensioners and adjustable tension devices 13, 23 — i.e., the concept of handling two strands in parallel with independently adjustable tension.
• §102 relevance: Does not anticipate any claim. The two-strand concept touches the capability recited in the specification (two threads in two adjacent positions) but not a single claim element of the structure: there are no pairs of cups, no juxtaposed hubs sharing a common shaft, and no central cylindrical track of claim 1, 2, 3 or 4. It is at most a §103 secondary reference for the two-strand objective.

3.3 US 3,525,205 A — Degli Antoni, "Yarn twisting, bulking and winding machine"

• Full citation: US 3,525,205 A; priority 1964-11-05 (US filing 1968-03-04); published 1970-08-25.
• Brief description (from retrieved text): A machine combining real-twist (incl. double-twist) spindles, a heater, cooling, and winding; it uses feed/delivery rollers (roller 6/belt 8 and roller 19/belt 21) with a controlled speed differential (roller 6 runs "15 to 30%" faster than roller 19) to allow controlled shrinkage/relaxation of the yarn in the heating zone. Relevant to "relaxing/bulking after twisting."
• §102 relevance: Does not anticipate any claim. Its tension/feed control is by roller-and-belt nip pairs, not by nut-clamped cup pairs straddling a central track. It discloses none of the structural elements of claims 1–4. It is machine-environment art (a twisting + heat-treatment + winding machine) matching the FIG. 3/FIG. 4 context.

3.4 US 3,830,051 A — Palitex Project Co. GmbH, "Yarn guiding flyer mechanism…"

• Full citation: US 3,830,051 A; filed 1973-04-02; published 1974-08-20.
• Brief description (from retrieved text/abstract): A flyer mechanism on the yarn-entry tube of a two-for-one twister spindle, pivotal between a yarn-processing position and a yarn-threading position so yarn can be threaded with minimal manual handling (it even matches flyer length to tube length to avoid a gap for pneumatic threading).
• §102 relevance: Does not anticipate any claim. This reference addresses the threading-up difficulty — one of the problems US 4,693,068 also sets out to solve ("facilitate the thread-throwing operations"). That makes it good §103 context for the object of the invention, but it discloses no cup pairs, hubs, central track, or nut-tensioning, and therefore anticipates none of claims 1–4.

3.5 FR 2 268 884 A1 — Bourgeas–Fougeirol Atelier Con., tensioning device for yarn winding ⭐ closest art

• Full citation: FR 2 268 884 A1; filed 1974-04-26; published 1975-11-21. (Google Patents editorial summary: "Tensioning device for yarn winding comprises two plates — between which yarn passes and which are rotated by contact with common drive shaft.")
• Brief description: This is the very slackener the patent's own background describes. The specification of US 4,693,068 states the "yarn slackening device / overspeed delivery member" is "used … in those installations where a twist is communicated to the thread and which comprise a double twist spindle (FR-A No. 2 268 884)," and describes it as "a rotary device constituted by two cups between which passes the thread, said cups being mounted on a hub … locked in position … by a nut … said hub being frictionally mounted on a rotary shaft which is common to all the positions of one face of the machine."
• §102 relevance: Does not anticipate any of claims 1–4. It discloses only one pair of plates/cups (one tensioning station) on the common drive shaft. Consequently it lacks each distinguishing element of claim 1: "a first hub and a second hub … inner end … juxtaposed"; "a cylindrical track located adjacent the inner ends … fixedly secured to at least one of said hubs"; "first and second pairs of cups mounted on opposite sides of said cylindrical track"; and the recited diameter relation (external track diameter ≥ each side-track diameter). Claims 2, 3 and 4 likewise find no counterpart. Because anticipation under §102 requires every element in a single reference, FR 2 268 884 cannot anticipate.
• Why it matters: It is the primary §103 starting reference — the single-station slackener the claimed invention doubles up and re-configures around a central track. Any obviousness rejection would be built on FR 2 268 884 as the base.

3.6 FR 2 430 991 A1 — Asa Sa, "Yarn processing machine"

• Full citation: FR 2 430 991 A1; filed 1978-07-12; published 1980-02-08.
• Brief description: A double-twist machine with a heat-treatment oven and a winding package, arranged with minimum spatial requirement. This is the FR-A No. 2 430 991 expressly cited in the specification of US 4,693,068 as the machine "in which a heat treatment is conducted after the twisting operation" (the FIG. 4 application).
• §102 relevance: Does not anticipate any claim. It is machine-environment art showing where a slackener is installed (twisting → oven → winding) so that two successive slackening operations become desirable. It discloses no slackener cup/track/hub structure and so reads on none of the structural limitations of claims 1–4.

3.7 US 4,237,683 A — Verdol S.A., "Device for delivering yarns"

• Full citation: US 4,237,683 A; filed 1978-10-25; published 1980-12-09.
• Brief description: A yarn delivery device (the "positive/delivery" class of textile accessory, i.e., the overfeed/overspeed-delivery family to which the patent's own device belongs). It appears in Google Patents' "Similar Documents" list for the family (US 4,237,683 appears in both the citations and similar-documents sets).
• §102 relevance: None established. I could not retrieve the reference's own text. On the face of the record it is a yarn-delivery device, and there is no indication it discloses two nut-clamped cup pairs straddling a central cylindrical track secured to a hub. Flagged as unverified — a definitive §102 assessment of the 4,237,683 disclosure requires its full text, which I could not pull.

3.8 US 4,462,557 A — Milliken Research Corp., "Spring biased electromagnetically controlled tension control"

• Full citation: US 4,462,557 A; filed 1982-10-18; published 1984-07-31.
• Brief description: A tension-control device using spring bias plus electromagnetic control to regulate yarn tension — a different class of tensioner (electro-mechanical engagement of brake surfaces), not a rotating cup/hub slackener.
• §102 relevance: Does not anticipate any claim. The claimed invention's tension adjustment is purely mechanical — axial movement of nuts (9,10) varying cup pressure (claim 1: "tension … can be varied by axially moving the respective nut to change the pressure exerted upon the cups"). The Milliken device works on an electromagnetic principle and has no hubs, cup pairs, lateral rims, or central track. No claim is anticipated.

3.9 US 4,592,195 A — Charbonnier, "Device for making cabled yarns of improved regularity"

• Full citation: US 4,592,195 A; filed 1984-06-05; published 1986-06-03 (legally prior art as of its filing date, i.e., before the 1985-06-11 priority of the patent under analysis).
• Brief description: A cabling-yarn machine for improved regularity — part of the same family of "machine-environment" art (twisting/cabling + downstream treatment + winding) as references 3, 5 and 6.
• §102 relevance: Does not anticipate any claim. It concerns cabling regularity, not the structural slackener of claims 1–4. No disclosure of the two juxtaposed hubs, the central cylindrical track or the paired cup/track diameter relationship.

4. §102 anticipation conclusion (per claim)

Applying the rule that anticipation requires a single reference disclosing every element of the claim as arranged, with no reliance on the inventor's own teaching:

Net finding: The nine examiner-cited references do not anticipate any of claims 1–4 under 35 U.S.C. § 102. They are field/background art. Their collective teaching divides into three groups:

1. The single-station slackener — FR 2 268 884 (ref. 5): the base reference for §103.
2. Machine environments where the slackener is used — US 3,525,205 (ref. 3), FR 2 430 991 (ref. 6), US 4,592,195 (ref. 9).
3. Adjacent problem-solving art — threading/guiding ease (US 3,830,051, ref. 4), two-strand tension equalization (US 3,359,716, ref. 2), delivery devices (US 4,237,683, ref. 7), electro-mechanical tensioning (US 4,462,557, ref. 8), early throwing machines (US 2,177,039, ref. 1).

The most relevant single reference is FR 2 268 884 A1 — it is the closest prior art and would be the obviousness starting point, but it is a single-cup-pair device and cannot, by itself, render claim 1 or its dependent claims anticipated.

5. Explicit caveats

• Source of citations: the list and its dates are taken from the authoritative full text provided in the prompt (Google Patents "Patent Citations (9)"), not from a live USPTO query; I was unable to reach USPTO Patent Public Search / Patent Center with the available tools.
• Unverified full texts: I did not retrieve the actual specifications of US 2,177,039, FR 2 268 884, FR 2 430 991, US 4,237,683, US 4,462,557, and US 4,592,195. Their §102 characterizations above are based on their titles, dates, assignees, and (for FR 2 268 884 and FR 2 430 991) the description of them inside US 4,693,068 itself. To make the §102 findings airtight, the full text and claims of each reference — particularly FR 2 268 884 and US 4,237,683 — should be pulled and element-mapped line-by-line.
• No similar-number substitution: every reference above is an actual citation on US 4,693,068; I did not import the unrelated "'306 patent" (thermoformed pallet) or any other near-miss cited in earlier searches.
• If a certified anticipation/validity opinion is required, the next step is to obtain the full text of each cited reference (esp. refs. 5 and 7) and produce a claim-chart against each element of claims 1–4.

I'll ground this analysis in the actual prior-art list from the patent record. Let me try to retrieve details on the key references before writing.

Good — I retrieved the EP equivalent (EP0208628B1) text and details on US4237683 (Verdol). Let me pull details on the remaining key references for element-by-element mapping.

I have enough grounding to write the analysis. Note: my final confirmation searches were cut off by a tool limit, so several reference titles are all I could retrieve for certain secondary references — I flag that explicitly below. This section builds on the earlier summary and litigation sections rather than repeating them.

Obviousness Analysis — US 4,693,068 under 35 U.S.C. § 103

0. Sourcing note (read first)

• The authoritative source is the full text supplied in the prompt (Google Patents, https://patents.google.com/patent/US4693068/en), plus the record's "Patent Citations (9)" list.
• I retrieved useful full text for: US 4,237,683 (Verdol, "Device for delivering yarns") and the EP equivalent of the patent-in-suit (EP0208628B1, French text, http://data.epo.org/publication-server/rest/v1.2/patents/EP0208628NWB1/document.pdf). The EP text confirms the terminology mapping used below — notably that the US term "throwing" = the French "lancement" (start-up lapping of the yarn onto the rotating device).
• For US 3,359,716, US 2,177,039, US 4,462,557, US 3,525,205, US 3,830,051 I was able to obtain only the record's titles, dates and assignees — not the specifications. Any statement below about what those references "teach" beyond their titles is therefore inferential and flagged. (My searches for US 3,359,716 returned a different Deering Milliken patent, US 2,811,012, which I do not treat as the cited reference.)
• I make no representation about the prosecution history, which was not provided and which a real §103 challenge would require.

1. Governing framework

Statute. The application was filed 1986-06-05, so pre-AIA § 103(a) applies (no AIA § 102/103 date-shifting). Prior-art status therefore turns on pre-AIA § 102(a)/(b)/(e).

Standard. Because the patent issued over these references, a challenger must prove obviousness by clear and convincing evidence (presumption of validity, 35 U.S.C. § 282). The discussion below identifies where that burden would be easy and where it would be hard.

Graham factors: (1) scope/content of the prior art; (2) differences between the prior art and the claims; (3) level of ordinary skill; (4) secondary considerations. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), governs the combination question.

Level of ordinary skill (POSITA) — proposed. A mechanical engineer or textile-machinery engineer with a bachelor's degree (or equivalent practical training) and roughly 2–4 years of experience in yarn-handling/twisting-machine design; or a skilled machine technician with substantially more hands-on experience. This is a mature, empirical, mechanical arts field — the KSR observation that "the combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results" applies with particular force.

2. Claim construction of the load-bearing terms

Claim-differentiation: claim 1 is the broad genus (D ≥ d₁); claim 3 is the FIG. 1 species (D > cup rim); claim 4 is the FIG. 2 species (integral hub track, D < cup rim). Claims 2 and 3 are narrower and correspondingly harder to invalidate; claim 1 is the most vulnerable.

3. The prior-art set and its § 102 status

All from the record's "Patent Citations (9)."

4. Element-by-element mapping of claim 1

The single genuine difference between claim 1 and the base art is the structural packaging: duplication of the known cup-pair + a defined central cylindrical track whose diameter is tied to the cup contact circle, configured for start-up lapping. Everything else is expressly in the admitted art.

5. Grounds of rejection

Ground A (primary, directed at claim 1) — FR 2 268 884 + US 4,237,683

Rationale for combining (KSR/MPEP 2144.03(A) & (C)): combining two known elements, each performing its known function, using a known method (duplicating a known yarn-brake station on a common shaft), to achieve a predictable result (two yarns tensioned on one device). US 4,237,683 expressly addresses "delivering at least two yarns each taken from a different bobbin" and provides per-yarn brakes "between the dishes" of which each yarn is engaged, plus an idle drum and a separator — i.e., the art already knew to put plural yarn-braking elements around a common rotating body driven by a shaft shared with the machine. A POSITA facing a two-position machine (or a desire to slacken one yarn twice) would predictably juxtapose two of the known FR 2 268 884 cup-pairs on the same driven shaft.

Where the gap remains — and why it is a design choice, not invention: once the two hub/pair units are juxtaposed (their inner ends facing each other, as claim 1 requires), the region between them is necessarily a cylindrical space coaxial with the shaft. Embodying that space as a smooth cylindrical track secured to a hub is straightforward mechanical design, and KSR endorses "the use of a known technique to improve similar devices in the same way." Setting D ≥ d₁ is compelled by the intended start-up function: for the yarn to rest on the central surface rather than be nipped or to fall into the gap, that surface must be at least as large in radius as the cup contact circle. This is the classic result-effective optimization addressed by In re Aller / In re Boesch — and the record contains no comparative data showing criticality of the endpoint (the spec. shows only two embodiments and asserts no unexpected result).

Ground B — FR 2 268 884 + US 3,359,716 (Deering Milliken)

US 3,359,716's title — "Method and apparatus to equalize tension in two or more strands" — supplies the explicit two-strand motivation and the known desirability of equalizing tension across strands. Combined with FR 2 268 884, this supports "two yarns in two adjacent positions" (the FIG. 3 use). Caveat: I could not obtain US 3,359,716's specification, so I cannot say how it equalizes tension. If it turns out (as the related Deering Milliken art my search surfaced, US 2,811,012, does) to use capstan/gear coupling rather than a shared cylindrical running track, it is a weaker structural reference but still a strong motivation reference.

Ground C — Adding the "two-successive-treatments" motivation

FR 2 430 991 ("double twist spindle, heating means and winding package") and US 3,525,205 ("twisting, bulking and winding machine") — both cited in the patent's own background as multi-treatment installations — supply the motivation for the FIG. 4 use: slacken, heat-treat, slacken again. A POSITA seeking to place two adjustable tension stations on the path of one yarn would do exactly what claim 1 recites.

Ground D — Adding US 2,177,039 for "throwing"

"Thread throwing machine" (1939) shows the throwing/lapping step is old and well-known, supplying the motivation to facilitate it. Combined with the admitted problem (threads "get caught … when the threads are thrown"), this defeats any argument that the throwing-related limitations supply the inventive weight.

Claims 2–4 (dependent)

6. Arguments the patent owner would raise (and my assessment)

1. No reference discloses the central track as a throwing surface, with the D ≥ d₁ relationship. — The strongest non-obviousness argument. It is likely why the claim allowed. Its force is diluted because (a) the mechanism is a predictable mechanical expedient, (b) the problem is admitted in the specification, and (c) there is no criticality evidence. Still, with no reference showing the track-for-throwing feature, a challenger's §103 case rests heavily on "obvious design choice," which a fact-finder could reject under clear-and-convincing review. This is the case's principal vulnerability.

2. US 4,237,683 arguably teaches away. In Verdol, the drum is the working surface (yarns wrap ~250° of it during normal running) and a separator keeps the two yarns apart — the opposite allocation from the patent, where the central track is a non-working parking surface and the side tracks do the work. A skilled advocate can frame this as "the art directs yarn onto the central drum, not off it." Assessment: a weak–moderate teaching-away argument; a separator that keeps yarns apart is not a teaching that a central track cannot be used for lapping.

3. "Rotatable therewith" vs. frictional mounting. FR 2 268 884 mounts the hub frictionally (permitting slip), while claim 1 says the hubs are "rotatable therewith." If construed to require non-slipping drive, FR 2 268 884 alone would not meet that element and a secondary reference (US 4,237,683's shaft-driven drum) would be needed. Assessment: likely construed broadly (a friction drive still rotates the hub with the shaft); a modest claim-construction defense, not a validity salvation.

4. Method-of-use ("throwing") limitation gives patentable weight. Under In re Schreiber/In re Zierden, apparatus claims are generally not narrowed by intended use — unless the capability is structural. Claim 1's "in contact with said cylindrical track during a throwing operation" is arguably an inherent capability of the recited structure, so it adds little weight. Assessment: weak for the patent owner.

5. Foreign counterpart grants (EP0208628B1, DE3660671D1, FR2583028B1, ES8705334A1) are not evidence of US non-obviousness — foreign offices apply different (often problem-and-solution) standards. Assessment: no weight.

6. Secondary considerations. The record contains no evidence of commercial success, long-felt need, failure of others, copying, licensing, or unexpected results. The patent lapsed for non-payment on 1991-09-15 (per the record) — which, if anything, cuts against a commercial-success narrative. Assessment: neutral-to-negative for the patent owner.

7. Bottom line

• Claim 1 is the weakest claim and a credible §103 target, best attacked as FR 2 268 884 in view of US 4,237,683 (optionally + US 3,359,716 for the two-strand motivation and US 2,177,039 for throwing). The theory is KSR "known elements arranged by known methods with predictable results," plus obvious design choice for the central track and routine optimization for the D ≥ d₁ relationship.
• The decisive gap is that no cited reference expressly discloses a smooth central cylindrical track used as a start-up (throwing) surface with the recited diameter relationship. Absent that teaching, the rejection rests on the "obvious design choice/optimization" rationales, which must overcome the §282 presumption under clear and convincing evidence. Whether that succeeds depends on facts not in the supplied record: the actual disclosures of US 3,359,716, US 2,177,039, US 4,462,557, US 3,525,205 and US 3,830,051 (I had titles only for these), and any prosecution-history statements about the invention's advantage.
• Claims 2–4 are narrower and harder to invalidate; claims 3 and 4 are essentially alternative geometric species (D > rim vs. D < rim), so a finding that one is obvious via design choice tends to make the other obvious as the designer's binary option.
• Confidence: Moderate that a well-supported §103 rejection of claim 1 could be made; lower for claims 2–4. I would not characterize any claim as anticipated (§102) on this record.

Recommended verification before relying on this: retrieve the full specifications of US 3,359,716, US 2,177,039, US 4,462,557, US 3,525,205, US 3,830,051 (I only had titles), and obtain the US prosecution history (file wrapper) to see precisely which references the examiner applied and which claim limitations drove allowance — that is the single most probative evidence for how strong the central-track limitation really is.