US 8918258

I'll search for litigation and docket information on this specific patent, then compile the summary from the authoritative patent text provided.

US Patent 8,918,258 — Verification Summary

Important methodological note: I have no direct API access to USPTO PatentCenter or to a CAFC docket database. The results below come from the authoritative full patent text supplied to me plus open web searches. Where I cannot confirm something authoritatively, I say so explicitly. All identifiers were read literally; the search returned an unrelated Brazilian corporate registration file (jucisrs.rs.gov.br) containing the string "8918258" as a company registration number, and an unrelated UK patent (GB2224095B, application GB8918258A, "Autotensioner") — neither is the US patent at issue, and I have excluded them.

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Bibliographic Data

Two dates deserve a flag rather than a "correction." The face of the record lists a prior-art/priority date of 2012-09-28 but a filing date of 2012-10-23 — a gap of about three weeks. The specification's cross-reference cites provisional 61/707,381 as filed August 28, 2012. I am reporting these exactly as they appear; reconciling the 2012-09-28 priority date against the August 28, 2012 provisional is something I cannot do authoritatively from the material available.

Abstract (verbatim)

System and method for controlling a transmission in response to transient torque events are disclosed. The method includes commanding a maximum transmission output torque; comparing the commanded output torque to a feedback torque to determine if they are equal; and incrementally increasing the transmission output torque until equal. A machine and a powertrain include a controller configured to command a maximum negative transmission output torque in response to a transient torque event, and incrementally increase the transmission output torque until such time as the transmission output torque is equal to or within a preset range of the feedback torque.

Plain-Language Overview of the Independent Claims

The patent has three independent claims — claim 1 (method), claim 11 (powertrain), and claim 18 (machine) — all describing the same core control behavior from three statutory vantage points. (Claims 2–10 and 12–17, 19–20 are dependent.)

Claim 1 — Method (torque-controlled transmission). Covers a method of responding to a "transient torque event" that is caused by encountering an object and that produces a feedback torque. The steps are:

1. Command a maximum negative transmission output torque (i.e., drive the variator hard in the negative-torque direction as an immediate anti-lug response).
2. Compare that commanded torque to the actual feedback torque reaching the transmission.
3. Determine whether the commanded torque equals, or is within a predetermined range of, the feedback torque.
4. If not, sequentially incrementally increase the commanded output torque and repeat the comparison, looping until commanded torque matches the feedback torque (or falls within the range).

In plain terms: slam the variator to maximum negative torque, then "walk" the command back up in steps until it matches the real load, rather than relying on the operator to perceive the obstacle and back off.

Claim 11 — Powertrain. Same control logic, claimed as apparatus: an engine driving a transmission that drives ground-engaging members, plus a controller programmed to (a) respond to a transient torque event caused by encountering an object producing a feedback torque, (b) command maximum negative transmission output torque, (c) compare it to feedback torque from the ground-engaging members, and (d) incrementally increase output torque until it is equal to or within a preset range of the feedback torque.

Claim 18 — Machine. Same control logic again, claimed at the machine level: a frame supporting an engine connected to a transmission that selectively transforms engine speed/torque into output transmission speed/torque applied to ground-engaging members to propel the frame, plus a controller performing the identical command-compare-increment sequence.

Representative dependent-claim coverage:

• Claims 2–4: nature of the increments — equal increments (2), increments dependent on the commanded-vs-feedback torque difference (3), and decreasing increment size as the difference shrinks (4).
• Claims 5–6 and 9–10: stall detection with clutch disengagement (all clutches in 6 and 10) — this is the FIG. 6 fallback embodiment.
• Claims 7–8: the transmission is a CVT (7), and the command is executed by adjusting a variator swashplate angle (8).
• Claims 12–13, 15–16, 20: variator + transmission gears, controller commanding maximum negative variator output and incrementally increasing variator output.
• Claim 17: the transient event is an obstacle encounter with feedback torque transmitted via the ground-engaging coupling, with the controller adjusting output torque so engine underspeed is avoided.
• Claim 19: engine sensor signals imminent stall; controller disengages at least one clutch.

Prior Art Cited on the Face of the Patent (11 references)

US 6,385,970 B1 (Caterpillar, underspeed control for hydromechanical drive); US 6,595,885 B1 (Caterpillar, transmission control); US 2003/0228952 A1 (Nissan, toroidal CVT control); WO 2004/085190 A1 (Torotrak, CVT control); US 2005/0132702 A1 (Dorscht, CVT shredder drive); US 7,503,173 B2 (Parker-Hannifin, swashplate pump control); US 2009/0156360 A1 (Caterpillar, part-throttle optimization); US 7,822,532 B2 (Caterpillar, power-based underspeed control — note this is the issued counterpart of US 2009/0199814 A1 by Hoff et al., a common inventor); US 2009/0298635 A1 (Caterpillar, electric motor actuation of hydrostatic pump); US 2011/0087411 A1 (Fuller, electronic CVT controller); US 2011/0094214 A1 (Caterpillar, high-response hydraulic actuator).

Two patents cite it forward: US 10,174,704 B2 (Ford) and US 12,071,745 B1 (CNH Industrial America, "Load dependent range shift control").

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Litigation / CAFC 2026 Docket Check — No Results Found

I searched specifically for CAFC and district court activity tied to 8918258 / 8,918,258 and found no litigation, no IPR/PGR, and no Federal Circuit appeal involving this patent. The only hits were unrelated coincidences (a Brazilian state commercial-registry filing containing "8918258" and the unrelated UK GB application GB8918258A).

My conclusion, stated with appropriate caution: US 8,918,258 appears to be an unasserted Caterpillar patent. I cannot authoritatively confirm the absence of litigation, because I have no direct query access to PACER, the CAFC docket system, or the USPTO PTAB API — this rests on open-web search results and should be independently verified if a litigation-clearance or freedom-to-operate conclusion depends on it. Given the patent's stated expiration of 2033-04-03 and its continuation in force (8th-year maintenance fee paid in 2022), it remains a live asset despite the apparent lack of enforcement activity.

If it would be useful, I can next map this patent against the two forward-citing patents (Ford's 10,174,704 and CNH's 12,071,745) or against the related Caterpillar filings referenced in the specification (applications 13/484,632; 13/407,280; and 13/407,311).

I'll research litigation involving US patent 8918258 across patent litigation databases.

Let me run more targeted searches on litigation databases.

Let me search additional litigation-specific sources for this exact patent number.

Litigation Search Report — U.S. Patent No. 8,918,258

Bottom line

I found no record of any litigation involving U.S. Patent No. 8,918,258 ("System and method for avoiding engine underspeed and stall," Caterpillar Inc.). Based on the searches run, this patent appears to be unasserted.

What I searched and what I found

I ran targeted queries against publicly indexed patent-litigation and PTAB sources (including content surfaced from RPX/Unified Patents, Google Patents, PTAB/PTACTS documents, PACER-derived dockets via CourtListener/PacerMonitor, and general litigation coverage). Because I cannot directly authenticate into the Unified Patents portal or PACER, this report reflects what is publicly available/discoverable, not a certified PACER docket check.

No hits. Specifically:

• No district court case naming U.S. 8,918,258 as an asserted patent (Caterpillar as plaintiff or as defendant) was found.
• No CAFC appeal involving this patent was found.
• No PTAB proceeding (IPR/PGR/CBM) against this patent was found.
• The Google Patents record for US8918258B2 lists only two "Cited By" references (US 10,174,704 and US 12,071,745) and eleven cited references — no litigation section and no PTAB section, which is consistent with an unasserted patent.

Nothing responsive to the requested format (plaintiff / defendant / jurisdiction / case number / filing date / status) can be produced, because no such cases were identified.

Important caution — do not confuse these look-alike numbers

Several search results contain identifiers that resemble, but are not, U.S. 8,918,258. I flag these so they are not misread as litigation against this patent:

1. "the '891 patent" in the Google IPR petition (June 17, 2025) and in Bionics LLC v. MED-EL Elektromedizinische Geräte GmbH, IPR2019-01469 — These refer to different patents (a telecom/standard-essential-style patent and a hearing-implant patent, respectively). The shorthand "'891" is a claim-number style reference, not U.S. 8,918,258.
2. GB8918258A / GB2224095B ("Autotensioner") — This is a UK application number, unrelated to U.S. 8,918,258.
3. Registration No. 8918258 (JUCISRS, Brazil) — A Brazilian state business-registry entry, unrelated.
4. US 12,071,745 B1 ("Load dependent range shift control," CNH Industrial) — This merely cites the '258 patent; it is not litigation involving it.

Other relevant facts I did confirm about the '258 patent

• Owner: Caterpillar Inc. (assignee of record per USPTO assignment, reel/frame 029182/0178).
• Application: US 13/658,465, filed Oct. 23, 2012; priority to provisional US 61/707,381 (filed Aug. 28, 2012).
• Grant: Dec. 23, 2014 (US 2014/0095035 A1 published Apr. 3, 2014).
• Status: Active; adjusted expiration listed as Apr. 3, 2033; maintenance fees paid (4th year 2018; 8th year 2022). No indication of lapse, disclaimer, or reexam in the records reviewed.
• Inventors: Brian D. Hoff, Michael Barngrover, Mark E. Rettig.

Recommended next steps for a definitive clearance

If a certified negative is required (e.g., for a freedom-to-operate or diligence opinion), I recommend confirming directly against:

• PACER / CourtListener RECAP (full-text docket and document search) for "8,918,258" and "8918258";
• Unified Patents Portal litigation and PTAB charts (https://portal.unifiedpatents.com/litigation/caselist) — requires account access;
• USPTO Patent Center / PTAB API for any IPR/PGR against the patent;
• Lex Machina / Docket Navigator for complete district-court coverage, including cases that may have settled or been dismissed early.

Caveat: This report is based on publicly searchable records as of the search date and is not a substitute for a certified PACER/Unified Patents docket check. I did not find any litigation, but I cannot rule out a case that is not publicly indexed or that is sealed.

PTAB / AIA Trial Report — U.S. Patent No. 8,918,258

Patent: US 8,918,258 B2 — "System and method for avoiding engine underspeed and stall"
Owner of record: Caterpillar Inc. (assignment recorded 2012-10-24, Reel/Frame 029182/0178)
Application: 13/658,465 · filed 2012-10-23 · granted 2014-12-23 · adjusted expiration 2033-04-03
Claims: 20 total — independent claims 1 (method), 11 (powertrain), 18 (machine); dependents 2–10, 12–17, 19–20

Consistency note with the previously generated sections: the patent summary and litigation report in this prompt both concluded there was no IPR/PGR activity. My independent searches reach the same result. No contradiction to flag.

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Proceedings overview

Total AIA trial proceedings on file: zero (0). That is the count from the structured "PTAB proceedings on file" block (USPTO Open Data Portal — "no AIA trial proceedings for this patent as of the most recent ingest"), and it is corroborated by independent web searching: 0 IPRs, 0 PGRs, 0 CBMs; 0 institution decisions; 0 final written decisions; 0 appeals. There is no breakdown by status to give, because there is nothing in any status category — no active trial, no invalidated claims, no sustained claims, no settlements, no denials.

Defensive posture this yields: the patent is neither hardened nor softened by the Board. All 20 claims — including the three independents — are completely untested at the PTAB. A prospective defendant inherits the full statutory toolkit unencumbered by anyone else's estoppel, but also gains no free head start from an existing record. This is a clean-slate patent, not a hardened one: the "hardened" label would require a prior petitioner to have lost, and nobody has ever stepped up.

Proceedings list

No proceedings exist to enumerate. The required per-proceeding template (type / filed / status / panel / grounds / institution decision / FWD / settlement / appeal) is not populated because fabricating a docket entry would be the only way to fill it.

Look-alike results excluded (flagging these so they are not misread as activity against the '258 patent — all surfaced in my searches, all unrelated):

Sources checked: the Google Patents record (https://patents.google.com/patent/US8918258/en), which carries no "PTAB" and no "Litigation" section — a data point that is itself consistent with a never-challenged, never-asserted patent; the structured ODP block in this prompt; and open-web searches for the patent number paired with "IPR," "PTAB," and "final written decision." PTAB public documents are searchable at https://ptacts.uspto.gov/ptacts/ (PTAB E2E / public-information portal), and any Board decision would be retrievable via CourtListener at https://www.courtlistener.com/?q=8918258 or the Unified Patents litigation/PTAB portal at https://portal.unifiedpatents.com/litigation/caselist.

Confidence caveat, stated plainly: I have no authenticated API access to the USPTO ODP/PTAB API, PatentCenter, or PACER. My negative is built on the structured ODP block plus publicly indexed sources. For a clearance opinion, confirm directly against the PTAB API and PTAB E2E.

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Strategic summary

Claim status: 20 of 20 claims UNTESTED. None CANCELED. None SUSTAINED. There has been no certificate under 35 U.S.C. § 318(b), no cancellation, no confirmation, no substitute claim. Claims 1, 11, and 18 — the three independent claims that carry the commercial weight — stand exactly as issued on 2014-12-23. The only confirmed-fact defensive asset the patent lacks is any adverse Board record; the only defensive liability it lacks is any favorable Board record a defendant would have to overcome. Because there is no FWD, 35 U.S.C. § 315(e)(2) estoppel applies to no one. There is no petitioner, no real party in interest, and no privy who is foreclosed from raising anything. Any ground a defendant wants to run — §§ 102, 103, or 112 (§ 311(b) limits IPR to §§ 102/103 on patents and printed publications) — is available to them as a matter of first impression.

A structural point worth flagging: PGR is not available, and the window is long closed. The '258 patent's effective filing date (provisional 61/707,381 filed 2012-08-28; nonprovisional 13/658,465 filed 2012-10-23) predates the March 16, 2013 first-inventor-to-file transition. PGR under 35 U.S.C. § 321 therefore never applied to this patent, and in any event the nine-month post-grant window from 2014-12-23 would have shut on 2015-09-23. CBM review under AIA § 18 likewise is unavailable (not a business-method patent, and the CBM program sunset on 2020-09-16). IPR under §§ 311–319 is the only AIA trial vehicle, and it remains available at any time — subject only to the § 315(b) one-year bar from service of a complaint (inapplicable, since the patent has never been asserted) and § 315(a)(1) (no declaratory-judgment action has been filed). The pre-AIA status also matters substantively: any § 102 analysis proceeds under pre-AIA § 102(a)/(b)/(e)/(g), including pre-AIA § 102(b) on-sale and public-use art and pre-AIA § 103(a).

Pattern signals — all negative, and the absence is the signal. No petitioner has filed a single petition, let alone multiple petitions; there is no serial-challenger pattern to study; there is no defensive aggregator (Unified Patents, RPX, or similar) in the chain; and Caterpillar has never had to defend a PTAB appeal of this patent. Contrast that with Caterpillar's actual PTAB posture, which is highly active — but as a petitioner against others (the Wirtgen road-milling family, Miller International's coupler patents), and as a patent owner in the Wirtgen-driven IPRs on other Caterpillar patents. Caterpillar is plainly a sophisticated, well-lawyered, PTAB-experienced patent owner. That cuts both ways for a defendant: the owner knows the forums, but the owner has also had every opportunity — for over eleven years since grant, across multiple parallel campaigns where this patent would have fit naturally — and has not asserted the '258 patent or defended it at the Board. The likeliest explanations are that the claims are narrow and machine-specific (a control-loop claim capped by a "maximum negative transmission output torque" starting condition), or that Caterpillar practises the technology itself and prefers it as a defensive/freedom-to-operate asset rather than a licence-revenue one. Either way, the practical read for a defendant is that this is a sleeping patent, and the narrowness of claim 1 is the thing to prize open if it ever wakes up.

Practical prior-art note. Any future IPR would live in CPC B60W30/1884 ("Avoiding stall or overspeed of the engine"), B60W10/02 (driveline clutches), F16H61/472 (hydrostatic automatic regulation for target output torque), and B60Y2300/56 (engine stall prevention). The eleven references already on the face of the patent — notably US 6,385,970 and US 7,822,532, both Caterpillar underspeed-control patents, plus US 6,595,885, WO 2004/085190 (Torotrak), and US 2011/0087411 (Fuller) — are the starting point, and because the examiner already considered them, a petitioner would need art the Office "did not have before it or fully consider," which is the standard framing Caterpillar itself used as petitioner in IPR2015-00416.

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Recommended next steps

Because no PTAB activity exists, state that plainly — and treat it as a signal, not a gap. Zero IPRs on an eleven-year-old, in-force, large-entity Caterpillar patent is confirmatory evidence that the patent is unasserted. It does not, however, mean the patent is weak; it means it is untested.

1. Confirm the negative before relying on it. Query the USPTO PTAB API / ODP and PTAB E2E (https://ptacts.uspto.gov/ptacts/) directly for patent number 8918258, and run a CourtListener RECAP full-text search (https://www.courtlistener.com/?q="8,918,258") for any Board or district-court matter. A certified negative is required for FTO/diligence work.

2. If you are a defendant and receive a demand: there is no FWD to cite and no canceled claim to point at — the entire validity defence must be built from scratch. Note the one-year § 315(b) clock from service of a complaint; it is currently unstarted because nothing has been served.

3. If you are considering an IPR petition: target claims 1, 11, and 18 first, with dependents 2–10, 12–17, 19–20 as the fallback set. The strongest attack surface is the "maximum negative transmission output torque" / increment-until-match control sequence of claim 1 — a classic candidate for an obviousness combination of an underspeed/anti-stall control reference with a hydrostatic-variator displacement-control reference. Do not overlook the priority-date wrinkle, which the earlier sections in this analysis flagged but could not reconcile: the record shows a listed prior-art/priority date of 2012-09-28 while the cross-referenced provisional (61/707,381) is stated as filed 2012-08-28. For § 102 prior-art dating, brief the earliest defensible critical date (2012-08-28) and have art that predates it, so the petition survives a priority challenge.

4. Alternative vehicle if IPR estoppel exposure or claim-scope risk is a concern: ex parte reexamination under 35 U.S.C. §§ 301–307 is unavailable to no one here (it may be filed anonymously, carries no § 315(e) estoppel, and is limited to patents and printed publications). It is a slower but estoppel-free route, useful if the client does not want to appear as a petitioner.

5. Trial-stage milestones: none, because no trial exists. No institution-decision deadlines, no oral hearing dates, no § 316(a)(11) one-year FWD deadlines are pending. If a petition is ever filed, note that the § 314(b) institution deadline (six months from the patent owner's preliminary response or its due date) and then the statutory one-year FWD clock from institution will govern.

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Basis and limits: this report rests on the structured ODP "PTAB proceedings on file" block supplied in this prompt, the Google Patents record for US8918258B2, and open-web searches. It is not a substitute for an authenticated PTAB API/PTAB E2E/CourtListener query. Date format throughout: YYYY-MM-DD.

I'll verify whether any additional assignment records exist beyond the single one visible in the authoritative text, then compile the report.

Assignment & Ownership Chain Analysis — U.S. Patent No. 8,918,258

Primary source consulted: USPTO Patent Assignment Search / Assignment Center (https://assignmentcenter.uspto.gov/ and https://assignment.uspto.gov/patent/index.html) as reflected in the Google Patents legal-events record for US8918258B2, plus open-web cross-referencing. I do not have authenticated API access to the Assignment Center, so the reel/frame below is taken from the authoritative patent text supplied to me (which reproduces the USPTO-recorded legal event); every other link in the chain is a negative finding from search, not a certified docket read.

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Inventors

Departure pattern — not present. This is the notable negative. Continuity evidence:

• Brian D. Hoff has 46 Caterpillar-assigned patents through 2025-12-31 per Patent Leaderboard, with the most recent being US 11,333,140 (granted 2022-05-17, "Cooling block for multi-cylinder air compressor") — i.e., he was still filing under Caterpillar roughly a decade after the '258 filing. Source: https://www.patentleaderboard.com/caterpillar/brian-d-hoff/[827739](/patent/827739)
• Mark E. Rettig co-invented later Caterpillar grants including US 9,970,347 and US 9,969,402 (both 2018-05-15) — https://www.patentleaderboard.com/caterpillar/brian-d-hoff/827739 (same table).
• Michael Barngrover: I found no post-2014 Caterpillar filings attributable to him, but I also found no evidence of departure, transfer, or a competing employer. Absence of hits in a name-based search is weak evidence here, so I mark his status unclear rather than asserting a departure.

Why this matters for a fire-sale hypothesis: the classic precursor to a portfolio dump — all inventors exiting the original assignee within ~12 months of filing — is affirmatively contradicted for two of three inventors. There is no inventor-side signal of abandonment.

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Original assignee

Caterpillar Inc. (Delaware corporation; 100 N.E. Adams Street, Peoria, IL 61629-9620), per the USPTO assignment recorded at Reel 029182 / Frame 0178 and per the issued patent front page. Current assignee on the Google Patents record: Caterpillar Inc. — unchanged since issue.

• Primary line of business: manufacture and sale of construction, mining, energy and transportation machinery and engines. The patent is directed at the drivetrain control layer (hydrostatic/split-torque CVT variator control) of exactly those products.
• Did they ship a product embodying the claims? Yes, with high confidence on the vehicle-level reading, moderate confidence on claim-element-level mapping. The specification itself frames the embodiments around the wheel loader (FIG. 1) and the split-torque CVT with a hydrostatic variator pump/motor (FIGS. 3–4), which is Caterpillar's own production architecture for its large wheel loaders. Caterpillar's 10-K segment descriptions confirm ongoing manufacture of wheel loaders and integrated drivetrain systems (https://barchart.websol.barchart.com/?module=secFilings&popup=1&accession_num=0000018230-22-000223). Caveat: I did not perform a claim-chart-to-serial-number mapping, so "ships a product embodying the claims" is a contextual inference from the specification's own machine description, not a verified infringement/product analysis.
• Current status: Operating. Caterpillar is a public reporting company (CIK 18230), never filed for bankruptcy protection, and shows FY2023 worldwide sales and revenues of ~$67.1 billion in its own TTAB pleading (ttabvue-91294852-OPP-1.pdf). Not acquired, not dissolved, not in bankruptcy.

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Assignment timeline

One recorded assignment in the entire chain. The Google Patents legal-events table for US8918258B2 shows exactly three event types: (a) the assignment, (b) the grant event (STCF), and (c) two maintenance-fee payments (MAFP). There is no security agreement, merger, change of name, license recordation, release, correction, or post-issuance transfer.

• 2012-09-10 to 2012-10-11 (executed — earliest to latest signor) / recorded 2012-10-24 — Reel 029182/0178
  • Conveyance: Assignment — "ASSIGNMENT OF ASSIGNORS INTEREST" (per the Assignment Center abstract reproduced in the legal events table)
  • Assignor: Hoff, Brian D.; Barngrover, Michael; Rettig, Mark E. (signed jointly)
  • Assignee: Caterpillar Inc., Illinois
  • Correspondent: Not determinable from the sources I can reach. The Google Patents legal-event entry reproduces the reel/frame, the assignors, the assignee and the signing dates but does not expose the correspondent of record, and I could not retrieve the Assignment Center abstract page itself. I am not going to guess a name here; fabricating the correspondent would defeat the one diagnostic this task most depends on.
  • Context: Original employment/obligation assignment, recorded pre-issue (the application was filed 2012-10-23 and the assignment was recorded 2012-10-24, the day after filing). This is an ordinary in-bound inventor→employer transfer, not a reorg, fire-sale, securitization, or transfer-to-asserter.

Observations and flagged uncertainties on this single link:

1. Execution post-dates the provisional. The application claims priority to provisional 61/707,381, filed 2012-08-28, but the earliest signor executed on 2012-09-10 — after the provisional was filed. The recorded abstract does not identify a specific application serial number on its face, so whether this one instrument also assigned the provisional (versus only application 13/658,465) is unclear. For a strict chain-of-title review, this is the kind of gap worth confirming against the actual assignment document, since provisional rights would otherwise rest on an equitable obligation.
2. No evidence of any instrument touching the '258 patent after 2012-10-24. The legal status "Active, expires 2033-04-03" plus 4th-year (2018-05-09) and 8th-year (2022-05-18) maintenance payments paid by "LARGE ENTITY" is consistent with an uninterrupted Caterpillar ownership record — a small entity mispayment or an assignee change is not indicated.
3. Contradiction with the prior section, flagged as requested: the earlier Patent Summary flagged an unexplained gap between the listed prior-art/priority date 2012-09-28 and the filing date 2012-10-23, against a provisional filed 2012-08-28. The assignment record adds a third data point in the same neighborhood — inventor execution on 2012-09-10 — and does not resolve the discrepancy. I am reporting all three dates literally and not reconciling them.
4. Correspondent cross-reference (different chain, explicitly not a match): A separate, much older Hoff→Caterpillar assignment — Reel 014824/0863, executed 2003-12-17/18, recorded 2003-12-22, for US 7,462,970 — names correspondent Ryan C. Stockett, Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, 1300 I Street NW, Washington DC (https://www.plainsite.org/patents/assignment.html?id=[2780998](/patent/2780998)). This establishes that Caterpillar used Finnegan Henderson as recording counsel in that era, but it is not the correspondent on Reel 029182/0178 and I do not treat it as recurrence on this chain. It is useful only as a lead if the Assignment Center abstract for 029182/0178 needs to be chased.

Bottom line for this section: with only the original assignment on record and no successor-in-interest, the chain terminates at the original assignee. Under the task's own instruction, that is itself the finding: Caterpillar Inc. still owns the patent.

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Timeline diagram

timeline
    title Ownership of US 8918258
    2012 : Provisional 61707381 filed Aug 28
         : Application 13658465 filed Oct 23
         : Inventors assign to Caterpillar Inc
    2014 : Patent US 8918258 B2 issued
    2018 : 4th year maintenance fee paid
    2022 : 8th year maintenance fee paid
    2033 : Scheduled expiration Apr 3

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NPE / troll-pattern signals

Signal score: 0 present, 1 unclear, 7 absent.

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Verdict

Insufficient data — in the specific sense the rubric defines: only the original assignment is on record.

Justification: the complete recorded chain consists of a single conveyance at Reel 029182/0178, executed 2012-09-10 to 2012-10-11 and recorded 2012-10-24, from the three named inventors to Caterpillar Inc., and the Google Patents legal-events record for US8918258B2 contains no subsequent assignment of any kind — only the grant event and 4th-year (2018) and 8th-year (2022) maintenance-fee payments by a large entity. Because ownership never left the original operating assignee, none of the eight NPE signals can be evaluated meaningfully, and the correct output is not "no NPE" as an affirmative clearance but "insufficient data" arising from a one-link chain. The single genuinely diagnostic field — the correspondent of record on Reel 029182/0178 — is not exposed in any source I could reach, and I have deliberately left it blank rather than infer a name; recovering it from the Assignment Center abstract (or from the assignment document itself via Patent Center) is the one step that would convert this from a structural negative into a confirmed one.

Verification link: https://assignmentcenter.uspto.gov/ (search by patent number 8918258; alternate front end at https://assignment.uspto.gov/patent/index.html). Caveat: this analysis reflects publicly searchable records and the authoritative patent text; it is not a certified USPTO Assignment Center or PACER docket check, and I cannot rule out an unrecorded or unindexed instrument.

I'll research the specific prior-art references cited on the face of US 8,918,258. Let me run targeted searches on the USPTO records for the patent and its cited references.

Now let me research the remaining cited references.

Prior-Art Analysis — U.S. Patent No. 8,918,258 B2

Scope and method note

I queried the USPTO/Google Patents records for US 8,918,258 and its front-page citations. The patent itself is confirmed as US 8,918,258 B2, "System and method for avoiding engine underspeed and stall," Caterpillar Inc., inventors Hoff/Barngrover/Rettig, application 13/658,465, granted 2014-12-23 (authoritative full text supplied). The face of the patent lists 11 cited references, reproduced below.

Two honesty caveats before the analysis:

1. I hit a tool-call limit partway through gathering full-text detail. I obtained verified full text for the Caterpillar underspeed references (US 6,385,970; US 6,595,885; US 2009/0156360; US 7,822,532 / US 2009/0199814; and confirmation of the Nissan reference US 2003/0228952 A1). For the remaining five (WO 2004/085190 A1, US 2005/0132702 A1, US 7,503,173 B2, US 2009/0298635 A1, US 2011/0087411 A1, US 2011/0094214 A1), I rely on the citation data on the face of the '258 patent plus the reference titles; those descriptions are flagged as title-level only.

2. On the § 102 question specifically: all 11 are examiner-cited references. Based on the full text I reviewed, none of them appears to disclose, in a single reference, every element of independent claim 1/11/18 — in particular the specific ordered sequence of "command maximum negative output torque → compare to feedback torque → sequentially incrementally increase the commanded torque → repeat until equal." These references are therefore best characterized as § 103 obviousness art that individually anticipates narrower dependent claims or supplies elements of the independent claims, not as clean § 102 anticipators of the independent claims as a whole. I flag per reference where the anticipation exposure is strongest versus where it is only a sub-element. I cannot certify anything as a § 102 anticipation without a full element-by-element comparison against each reference's complete disclosure, which the available excerpts do not always permit.

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Summary table of cited references

(Dates are as listed in the patent's citation tables and as confirmed in the individual records I retrieved.)

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Reference-by-reference analysis

1. US 6,385,970 B1 — Caterpillar, "Underspeed control system for a hydromechanical drive system and method of operating same"

• Dates: CIP of Ser. No. 09/136,949 filed 1998-08-20; granted 2002-05-14.
• Disclosure (verified full text): A control system for a hydromechanical CVT. An engine-speed sensor and a travel-speed sensor feed an electronic controller that compares engine speed to an "underspeed value," generates an integral error signal, applies a proportional-plus-integral (PI) feedback controller with a travel-speed-based integral gain, and produces a command signal that controls the CVT transmission ratio to regulate engine load. Directional/high-speed clutches and a low-speed clutch are named.
• Relevance / potential § 102 exposure: This is the closest conceptual Caterpillar predecessor — engine underspeed detection feeding a CVT ratio command. It anticipates the general idea embodied in claims 7 (transmission is a CVT) and the underspeed-avoidance environment of claim 17, but it operates by regulating transmission ratio via PI control on engine speed — it does not teach commanding a maximum negative output torque and sequentially incrementally increasing it against a feedback torque as claim 1 requires. So it is strong § 103 art but not a § 102 anticipation of claims 1/11/18. Note this is a common-assignee (Caterpillar) reference.

2. US 6,595,885 B1 — Caterpillar, "Transmission control system and method"

• Dates: filed 2001-12-28; granted 2003-07-22.
• Disclosure (verified full text): A split-torque transmission combining a mechanical transmission (with at least one clutch) and a hydrostatic transmission (variable-displacement pump). An engine-speed sensor detects a severe underspeed; when engine speed drops below a stall limit, the control disengages at least one clutch and modifies pump displacement to let engine speed recover above the stall limit. It explicitly addresses a work pile encounter dropping groundspeed/engine speed and the risk of stall.
• Relevance / potential § 102 exposure: This reference is directly material to the FIG. 6 fallback claims — 5, 6, 9, 10, 14, 15, 19 — i.e., "detect an engine stall condition and disengage at least one clutch." US 6,595,885 discloses clutch disengagement under a stall-limit condition in a split-torque hydro-mechanical drivetrain. If the independent claims were construed narrowly, this reference supplies the clutch-disengagement element; as to the dependent clutch claims, its disclosure is close to anticipatory in substance (though claim 6/10 add "all clutches," and claim 5/9 pair disengagement with the incremental-increase method of claim 1, which US 6,595,885 does not show). Not a § 102 anticipation of claim 1/11/18.

3. US 2003/0228952 A1 — Nissan, "Toroidal continuously variable transmission control apparatus" (granted US 6,931,316 B2)

• Dates: 2002-06-05; published 2003-12-11; granted 2005-08-16.
• Disclosure (title-level + record confirmation): A Nissan toroidal CVT control apparatus; a related Nissan family (e.g., US 6,409,625) concerns hydraulically controlling power rollers/trunnions and limiting differential pressure to prevent sharp downshifts. This is speed-ratio / ratio-control art for a toroidal traction CVT.
• Relevance / potential § 102 exposure: Purely a variator/ratio control reference. It is background art for claim 8 (swashplate/variator adjustment) only in the general sense of controlling a CVT variator; it does not address engine underspeed, torque limiting, maximum negative output torque, or incremental torque stepping. No § 102 anticipation of any claim of the '258 patent; at most cumulative § 103 art for the CVT/variator environment.

4. WO 2004/085190 A1 — Torotrak, "Method of controlling a continuously variable transmission"

• Dates: 2003-03-27; published 2004-10-07.
• Disclosure (title-level only — full text not retrieved): Torotrak is the paradigmatic toroidal traction-drive CVT developer; this PCT document concerns a method of controlling a CVT, generally directed to ratio/torque control of toroidal variators.
• Relevance / potential § 102 exposure: General CVT-control background. Without the full text I cannot assign specific claims; on its title and art unit it does not appear directed to engine-underspeed torque-stepping. No identified § 102 anticipation; treat as § 103 environment art for the CVT claims (7, 8, 12, 13).

5. US 2005/0132702 A1 — Dorscht, "Continuously variable torque shredder drive"

• Dates: 2002-06-14; published 2005-06-23.
• Disclosure (title-level only — full text not retrieved): A continuously variable torque drive applied to a shredder (industrial machine), not a vehicle underspeed control.
• Relevance / potential § 102 exposure: Peripheral. It concerns CVT torque delivery in a non-vehicular context. No identified § 102 anticipation. Appears cited as general CVT-torque-control background.

6. US 7,503,173 B2 — Parker-Hannifin, "Control devices for swashplate type variable displacement piston pump"

• Dates: 2005-02-08; granted 2009-03-17.
• Disclosure (title-level only — full text not retrieved): Control devices/actuators for a swashplate-type variable-displacement piston pump — the hardware element that is the "variator pump 309" in the '258 patent's FIG. 4.
• Relevance / potential § 102 exposure: A component reference. It is material to the swashplate-actuation subject matter underlying claim 8 ("adjusting the angle of the swashplate") and the FIG. 4 actuator/ePRV description, but it teaches the mechanism, not the control method of claims 1/11/18. No § 102 anticipation of the independent claims; possible § 103 support regarding swashplate control hardware.

7. US 2009/0156360 A1 — Caterpillar, "Part-throttle performance optimization"

• Dates: filed 2007-12-13; published 2009-06-18. Inventors Barngrover, Sopko, Kuras, and Hoff.
• Disclosure (verified full text): A CVT anti-lugging system using an Engine Underspeed Algorithm (EUA) and "desired engine speed shaping." The EUA detects when actual engine speed falls below a speed standard by more than a gap value and then reduces the power/torque request to the drivetrain/implement/parasitic loads to avoid lugging. Speed shaping limits how rapidly the desired speed rises so the EUA does not over-correct.
• Critical overlap note: This reference shares at least one common inventor (Brian D. Hoff) and the same assignee (Caterpillar) with the '258 patent — relevant to any § 102(a)/102(e) date analysis and to possible double-patenting/obviousness-type-double-patenting considerations, though it is a different invention (speed shaping vs. torque stepping).
• Relevance / potential § 102 exposure: It discloses engine-underspeed detection and reduction of the drivetrain torque/power request — the generic underspeed-avoidance backdrop. But it does not disclose commanding maximum negative output torque and incrementally increasing that command back toward feedback equality. No § 102 anticipation of claims 1/11/18; it is best characterized as § 103 art establishing the state of Caterpillar's own underspeed-control art.

8. US 7,822,532 B2 — Caterpillar, "Power-based underspeed control" (pre-grant pub. US 2009/0199814 A1)

• Dates: filed 2008-02-08; granted 2010-10-26. Inventor Hoff et al.
• Disclosure (verified full text): An EUA operating in the power domain: receives a torque command, converts it to a power command, clips/reduces the power command on sensing underspeed, then converts the reduced (underspeed-processed) power command back to the torque domain and issues it. Includes PI/PID gain scheduling and a post-processing step that may "issue a command that is not realistically attainable… [to] allow the transmission to unload as much as possible, e.g., when a grader blade hits a rock or pile."
• Critical overlap note: Again a common-inventor / common-assignee (Caterpillar) reference. The post-processing language ("unload as much as possible… when a grader blade hits a rock or pile") is conceptually adjacent to the '258 patent's "command maximum negative torque" response to an obstacle.
• Relevance / potential § 102 exposure: The closest Caterpillar underspeed-control art to the '258 concept, and the reference most likely to be cited in a § 103 combination against claim 1. But it reduces a power command and converts between power/torque domains; it does not recite the specific ordered maximum-negative → compare-to-feedback → sequential incremental increase until equal loop. No clean § 102 anticipation of claims 1/11/18; strong § 103 material, and material to the dependent "difference-based increments" claims (3, 4) via its PI/PID processing.

9. US 2009/0298635 A1 — Caterpillar, "Electric motor actuation of a hydrostatic pump"

• Dates: filed 2008-06-02; published 2009-12-03.
• Disclosure (title-level only — full text not retrieved): Actuating a hydrostatic pump with an electric motor (as opposed to the hydraulic/ePRV actuation of the '258 FIG. 4). The '258 specification expressly contemplates "a different type of actuator… such as an electric actuator."
• Relevance / potential § 102 exposure: Component/alternative-actuator art, material only to the variator-actuation implementation underlying claim 8. No § 102 anticipation of the method/apparatus/machine claims.

10. US 2011/0087411 A1 — Fuller, "Electronic controller for a continuously variable transmission and a method of control of a continuously variable transmission"

• Dates: filed 2008-03-20; published 2011-04-14.
• Disclosure (title-level only — full text not retrieved): An electronic CVT controller and CVT control method (non-Caterpillar third-party artisan).
• Relevance / potential § 102 exposure: General electronic-CVT-control background, relevant to the "controller configured to control the transmission" element common to claims 11 and 18. Without the full text I cannot tie it to the torque-stepping loop. No identified § 102 anticipation; possible § 103 environment art.

11. US 2011/0094214 A1 — Caterpillar, "High response hydraulic actuator"

• Dates: filed 2009-10-26; published 2011-04-28.
• Disclosure (title-level only — full text not retrieved): A high-response hydraulic actuator — again the class of hardware used to move the swashplate/variator (FIG. 4's ePRV-driven dual-acting piston), and the "swift response" theme ties to the '258 patent's goal of quick transient-torque response.
• Relevance / potential § 102 exposure: Actuator hardware art, material to the FIG. 4 variator-actuation implementation and claim 8; does not disclose the control method of claim 1. No § 102 anticipation of the independent claims.

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Consolidated § 102 / § 103 assessment

Characterizing the art: These 11 references cluster into three groups:

1. Engine-underspeed / anti-stall control (the most material): US 6,385,970; US 6,595,885; US 2009/0156360; US 7,822,532. All four are Caterpillar references, and two (US 2009/0156360 and US 7,822,532) share inventor Hoff with the '258 patent. Collectively they establish: detect engine underspeed → reduce/adjust drivetrain torque or ratio → optionally disengage clutches. Individually and together they do not disclose the '258 patent's signature sequence (command maximum negative output torque, compare to feedback torque, then sequentially incrementally increase the command until it equals the feedback).

2. CVT / variator control & hardware: Nissan US 2003/0228952; Torotrak WO 2004/085190; Dorscht US 2005/0132702; Parker-Hannifin US 7,503,173; Caterpillar US 2009/0298635 and US 2011/0094214; Fuller US 2011/0087411. These supply the CVT/variator/swashplate environment and hardware underlying claims 7, 8, 12, 13.

3. Component-level: the swashplate-pump and hydraulic-actuator references (US 7,503,173; US 2011/0094214).

Anticipation conclusion (stated with appropriate caution):

• No cited reference, on the full text I was able to verify, discloses every element of independent claim 1, 11, or 18 — specifically the "maximum negative command → feedback comparison → sequential incremental increase until equal" loop. I therefore cannot identify a clean 35 U.S.C. § 102 anticipation of the independent claims from this art set.
• The strongest § 102-adjacent exposure is on the dependent clutch-disengagement claims (5, 6, 9, 10, 14, 15, 19) via US 6,595,885 B1 (clutch disengagement + pump-displacement modification when engine speed drops below a stall limit), which is close to anticipatory for the "detect stall / disengage at least one clutch" feature standing alone — but those claims also import the claim-1 incremental-increase method, which US 6,595,885 lacks.
• The strongest § 103 combination would likely be US 6,385,970 or US 7,822,532 (underspeed detection + CVT/ratio or power-domain torque reduction) in view of a CVT torque-control reference, for claims 1, 7, 11, 17, 18.
• The common-inventor / common-assignee relationships among US 2009/0156360, US 7,822,532 and the '258 patent are worth flagging for any § 102(a)/(e) date and obviousness-type double-patenting analysis.

What I could not verify: full text for WO 2004/085190 A1, US 2005/0132702 A1, US 7,503,173 B2, US 2009/0298635 A1, US 2011/0087411 A1, and US 2011/0094214 A1 (tool-call limit reached). Their descriptions above are title-level only and should be completed before any formal anticipation/validity opinion. I also note again the date discrepancy flagged in the earlier section — the record shows a 2012-09-28 priority date while the specification cross-references provisional 61/707,381 as filed 2012-08-28; for a § 102 date analysis this should be resolved against the certified USPTO record, not from the Google Patents face page.

Bottom line: On the verified text, these 11 examiner citations are a § 103 portfolio against the '258 claims — an underspeed-detection/anti-stall cluster (Caterpillar) plus CVT/swashplate hardware art — rather than a set of individual § 102 anticipators. The independent claims' distinctive "maximum-negative-then-incrementally-increase-to-feedback-equality" limitation appears not to be met by any single cited reference.

I'll ground this §103 analysis in the actual cited references. Let me pull the key ones.

Let me pull the remaining cited references that matter for the combination analysis.

Obviousness Analysis — U.S. Patent No. 8,918,258 B2 under 35 U.S.C. § 103

Builds on the Patent Summary and Litigation Summary already generated. I do not repeat the bibliographic record, the claim taxonomy, or the litigation findings; I take those as given and focus on the § 103 question.

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1. Scope, sources, and a methodological caveat (read first)

The task directs me to use "the results from the Prior Art section of this page" — i.e., the 11 references cited on the face of US 8,918,258. What I actually have:

Caveat, stated plainly: I did not retrieve full claim text and full specifications for four of the eleven references. Any assertion I make about those four is confined to what their titles and bibliographic records support, and I flag it as such. A rigorous invalidity opinion would require the full documents (and, ideally, the prosecution history, which I do not have).

I also note up front: this is a validity analysis (patent presumed valid under 35 U.S.C. § 282; invalidity must be proven by clear and convincing evidence). The examiner had these 11 references before him and still allowed the claims. That does not immunize the patent, but it shifts the burden and means any combination I propose must be genuinely more than a post hoc reconstruction from the claims.

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2. The legal framework I am applying

Under KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), and MPEP § 2143, a § 103 rejection needs (1) all claim elements in the prior art, and (2) an articulated reason to combine. The recognized rationales I rely on below are:

• (A) Combining known elements according to known methods to yield predictable results;
• (C) Use of a known technique to improve a similar device in the same way;
• (D) Applying a known technique to a known device ready for improvement;
• (F) "Obvious to try" — where there is a finite number of identified, predictable solutions, a POSITA pursues the known options with a reasonable expectation of success.

Also relevant: KSR's instruction that design incentives and market forces (here, the well-documented fuel-economy advantage of CVTs over torque-converter drives — recited in the '258 specification itself) can supply the motivation.

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3. The inventive core, reduced to elements

Claims 1, 11 and 18 are the same algorithm from three statutory vantage points. Reduced to elements:

1. E1 — Detection of a "transient torque event caused by encountering an object" that produces a feedback torque.
2. E2 — Commanding a maximum negative transmission output torque.
3. E3 — Comparing the commanded output torque to the feedback torque to the transmission.
4. E4 — Determining equality / within-a-range.
5. E5 — Sequentially incrementally increasing the commanded torque, looping on E3–E4, until matched.
6. Dependent — equal increments (2); difference-dependent increments (3); shrinking increments (4); stall detection → clutch disengagement (5–6, 9–10, 14, 19); CVT (7); swashplate-angle command (8, 13, 16); variator + gears (12, 15, 20); obstacle-encounter framing with underspeed avoidance (17).

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4. Where each cited reference lands

4.1 US 6,385,970 B1 — the underspeed-control backbone

Retrieved text: the apparatus "compare[s] the engine speed signal to an underspeed value and produce[s] an integral error signal… modify the integral error signal through a proportional plus integral feedback controller to produce an underspeed request signal," and "the command signal is used to control the transmission ratio of the continuously variable transmission so as to control the load on the engine." Background: "operation of the hydraulic elements produce loads on the engine that causes engine 'stalling' or 'lugging.'" (US6385970B1)

→ Supplies E1's problem context (transient loading → lug/stall), engine-underspeed sensing, and closed-loop CVT load control. It does not teach output-torque-domain command, "maximum negative," or stepwise incrementing.

4.2 US 7,822,532 B2 — the closest single reference, and the most dangerous one

Retrieved text is remarkable for this analysis:

• "in a CVT-driven machine… there is generally no torque converter, and the machine resistance will be able to lug down and stall the engine absent an external control mechanism… the transmission is actively controlled, e.g., via a software Engine Underspeed Algorithm (EUA)… to avoid lug/stall."
• "A typical EUA reduces the drivetrain transmission speed demand, in reaction to a difference between the actual engine speed and the desired engine speed."
• Critically, on post-processing: "issuing a command that is not realistically attainable by the system, but which allows the transmission to unload as much as possible, e.g., when a grader blade hits a rock or pile." (US 2009/0199814 A1; US7822532B2)

→ This discloses E1 almost verbatim ("grader blade hits a rock or pile") and strongly suggests E2: commanding a deliberately unattainable extreme to unload the transmission. What "maximum negative" adds is only the sign/direction of that extreme — and in a system that must unload an engine driving into an immovable object, the unloading direction is the negative/reverse-torque direction by simple mechanics.

4.3 US 6,595,885 B1 — the stall-fallback and the "encounter" framing

Retrieved text: the invention is "directed to a method for controlling a transmission in a work machine… At least one clutch… is disengaged and the displacement of the source of pressurized fluid is modified when the operational speed of the engine drops below a stall limit." And the problem statement: "An engine underspeed situation may occur… when the work machine encounters a heavy load, such as a work pile… If the drop in engine speed is rapid enough, the control system may not be able to adjust the transmission quickly enough to prevent the engine from stalling." (US6595885B1)

→ Supplies E1 (object encounter producing load), and dispositively supplies the clutch-disengagement fallback of claims 5–6, 9–10, 14, 19. Claim 6's "all clutches" is a routine design choice over "at least one clutch."

4.4 WO 2004/085190 A1 / EP 1606135 B1 (Torotrak) — the torque-controlled-variator control loop

Claim 1 and the description teach the variator "exert[ing] upon its input and output members torques which, for a given variator drive ratio, correspond directly to the control signal," and a method comprising "predicting a consequent engine speed change… and correcting the settings… based on a comparison of actual and predicted engine speeds." (WO2004085190A8)

→ Supplies the command → compare-to-an-actual-feedback-quantity → correct loop (E3–E4) in exactly the torque-controlled-variator regime the '258 patent operates in.

4.5 US 2011/0087411 A1 (Fuller; granted as US 8,924,111) — output-torque-domain variator command

Claim 1 recites a loop: "measure a speed ratio… compare the measured speed ratio with a target speed ratio; determine a transmission output torque request on the basis of the said comparison; convert the output torque request to a control pressure request, taking account of the speed ratio; differentiate… and apply the compensation value… and output the resulting compensated control pressure request to the hydraulic valve arrangement." (US20110087411A1)

→ Supplies E2's mechanism: the concept of commanding the variator in the output-torque domain and translating that into a hydraulic control pressure for a swashplate/roller actuator — the exact chain the '258 claim 8 recites (swashplate angle). It also teaches differentiating/compensating the pressure request — a known technique for making the loop respond faster.

4.6 The hardware/actuation references

• US 7,503,173 B2 (Parker-Hannifin) — swashplate-type variable-displacement pump controls → the physical actuator for claim 8.
• US 2011/0094214 A1 (Caterpillar) — "High response hydraulic actuator" → teaches the fast-responding actuation needed to slam the variator to an extreme command quickly (supports why a POSITA would build the E2 step).
• US 2009/0298635 A1 (Caterpillar) — electric motor actuation of a hydrostatic pump → alternative actuator.
• US 2003/0228952 A1 (Nissan) — toroidal CVT ratio control that "electronically feedback-controls a transmission ratio based on a deviation from a desired transmission ratio" and issues an abnormal-period command to shift the ratio toward the speed-reduction side when the deviation cannot be corrected → an independent teaching of deliberately commanding an extreme ratio command when normal feedback control is inadequate (closely analogous to E2).
• US 2005/0132702 A1 (Dorscht) — CVT torque shredder drive → context for transient, object-induced torque spikes.
• US 2009/0156360 A1 (Caterpillar) — part-throttle performance optimization → engine-speed setpoint management.

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5. Proposed § 103 combinations and the motivation to combine

Combination A (strongest): 6,385,970 + 7,822,532 + 6,595,885

All three are Caterpillar, all in CVT/hystat work-machine driveline control, all addressing the same problem (engine lug/stall under transient load), and each supplies a distinct, non-overlapping piece:

Motivation: (i) Same field, same problem, two of three same assignee — the classic Rationale (C)/(A) case; a POSITA designing a Caterpillar-class CVT loader controller would consult these. (ii) Art-recognized deficiency being cured: 7,822,532 expressly states that without an external control mechanism a CVT-driven machine "will be able to lug down and stall"; 6,595,885 states the control "may not be able to adjust the transmission quickly enough." A POSITA is therefore motivated to make the anti-lug response faster and more decisive. (iii) Predictable results: combining a known underspeed loop with a known "command the unattainable extreme to unload" step, in a known fast actuator, yields nothing beyond the expected summing of their functions.

Combination B: add WO 2004/085190 + US 2011/0087411

These supply the torque-controlled-variator flavor that Combination A lacks (A's loops are largely engine-speed-domain). WO 2004/085190 supplies command/compare/correct in a torque-controlled variator; Fuller supplies the explicit output-torque-request → control-pressure chain. Motivation: Torotrak's own documents frame torque-controlled transmissions as a recognized class requiring electronics "to regulate the engine and transmission in unison," and Fuller explicitly solves the hydraulic lag problem — i.e., a POSITA seeking a fast, decisive torque command has a documented reason to adopt the output-torque-domain command path of Fuller/WO '190.

Combination C: dependent claims

• Claim 8 (swashplate angle): US 7,503,173 (swashplate control) + US 2011/0094214 (high-response actuator) make the swashplate-angle implementation routine.
• Claim 7 (transmission is a CVT): inherent to every reference.
• Claims 3–4 (difference-dependent / shrinking increments): pure optimization of a known iterative loop — Rationale (D); also the "obvious to try" rationale (a finite set of increment schedules: fixed, proportional, decaying).
• Claim 17 (obstacle encounter, underspeed avoidance): US 6,595,885 alone.

Combination D (secondary): Dorscht + Nissan for the "extreme command" idea

US 2003/0228952 (Nissan) independently teaches issuing an abnormal-period command to drive the ratio to a speed-reduction extreme when normal feedback control cannot fix the deviation. Paired with Combustion A, this supplies corroboration that "when feedback control is inadequate, command an extreme" was a known technique across CVT platforms.

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6. Element-by-element conclusion

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7. The honest counter-case (where a strong nonobviousness argument lives)

I do not think a § 103 rejection over these 11 references is a foregone conclusion, and I would be doing the analysis a disservice to say otherwise. Three points:

1. The specific E5 strategy is not squarely taught. Every substantive reference I retrieved teaches continuous PI/PID correction on an error signal (6,385,970; 7,822,532; WO '190; Fuller). The '258 claims recite something structurally different: a deliberate initial over-command to the extreme, followed by monotonic one-directional stepwise increase until the command meets the measured feedback torque. A patentee would argue the prior art teaches proportional correction, not saturate-then-climb; that the references' controllers move in both directions while '258's climb is one-directional; and that nothing suggests deliberately overshooting to maximum negative torque first. That is a real, non-frivolous distinction.

2. Teaching away / different operating philosophy — weakly. One could argue a PI/PID designer would be led away from the crude step-search of '258 (which sacrifices control smoothness). This is a weak argument — the references do not criticize stepwise search, and mere disclosure of a preferred alternative is not teaching away (In re Fulton). I would not rely on it alone.

3. The examiner already considered all 11 references and allowed. Combined with the § 282 presumption and the clear-and-convincing standard, any rejection would have to be built on a motivation the examiner did not articulate, most plausibly the 7,822,532 "command the unattainable extreme to unload" teaching read together with 6,385,970/6,595,885. That is the single most productive line of attack and the one I would develop first — but it requires full text of 7,822,532's claim set (I have only the published application's description) to be sure the "unload" teaching is in the disclosure rather than buried in a dependent claim.

Secondary considerations: I have no evidence of unexpected results in the '258 specification, and — per the Litigation Summary already generated — no identified commercial-success or licensing evidence with nexus (the patent appears unasserted). Notably, the '258 specification itself concedes the motivation by touting CVT fuel-economy advantages over torque-converter drives and framing its own contribution as removing "lag time" and operator dependence — an admission that maps onto Rationale (C).

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8. Bottom line

• Most likely to be held obvious: claims 5, 6, 9, 10, 14, 19 (clutch-disengagement fallback — disclosed essentially in full by US 6,595,885), and claim 17.
• Provisionally obvious with a well-articulated motivation: claims 2–4, 7, 8, 12–13, 15–16, 20 (routine implementation/optimization over the combined art).
• Contested: independent claims 1, 11 and 18. The combination of US 6,385,970 + US 7,822,532 + US 6,595,885, with WO 2004/085190 and US 2011/0087411 supplying the torque-controlled-variator output-torque-command chain, renders most elements obvious; but the "command maximum negative, then sequentially step up to the feedback torque" sequence (E2+E5) is the point on which the patent most plausibly survives, absent a reference I have not fully read that discloses saturate-then-climb.

Confidence: moderate on the apparatus/machine claims and the dependent claims; low-to-moderate on independent claim 1's E5, because I lack full claim text for four cited references and the full text of 7,822,532's claims.

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Flags and contradictions (per standing instruction)

1. Unverified attribution, not a contradiction: the earlier Patent Summary states US 7,822,532 is "the issued counterpart of US 2009/0199814 A1 by Hoff et al., a common inventor." My search confirms US 7,822,532 ↔ US 2009/0199814 A1 ("Power-based underspeed control") but I could not verify the "Hoff et al." inventorship from the retrieved material. I flag it as unverified rather than adopting or rejecting it. If true, a common-inventor, same-assignee reference raises the "same inventive entity / obviousness-type double patenting" and § 102(e)/§ 103(c) questions, which are worth a separate look.
2. Date inconsistency (housekeeping): the current-task header states "Current Date: April 26, 2026," while the operating metadata I was given elsewhere states 2026-09-29. I flag the discrepancy; nothing in this analysis turns on it.
3. Abstract vs. claims wording: the '258 abstract recites "commanding a maximum transmission output torque," whereas every independent claim recites "maximum negative." This is an internal inconsistency worth noting for claim-construction purposes, and it matters to § 103 because the negative sign is the only thing the cited art may not literally show.