US 8909437

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

Let me check specifically for litigation/docket data on this patent number.

Search Results Summary — US 8,909,437

Scope note up front: I found the patent itself in USPTO/Google Patents/FreePatentsOnline records, but my searches of CAFC 2026 dockets and district-court litigation databases returned no case, appeal, or docket entry naming US 8,909,437. The "8909437" hits that surfaced were false positives (a 1989 PCT publication WO 89/09437, a German utility model DE 8909437 U1, and a Bush Library FOIA document control number). I'm flagging this as a genuine negative result rather than asserting the patent has never been litigated — I simply could not find authoritative litigation data through web search.

Bibliographic Data (confirmed against the patent front page)

Minor discrepancy worth noting literally: the Google Patents URL slug renders the title as "Payload Estimatation system" (an apparent typo in that database), while the patent front page and FreePatentsOnline show "Payload Estimation System." Treating the front page as authoritative.

Abstract (verbatim)

"A payload control system includes a sensor system and a force sensor system. A controller determines a calibration machine state, a calibration linkage force, and machine calibration parameters based at least in part upon the calibration machine state and the calibration linkage force. The controller also determines a loaded implement machine state, a loaded implement linkage force, and a mass of the payload based at least in part upon the machine calibration parameters, the loaded implement machine state, and the loaded implement linkage force."

Plain-Language Overview of the Independent Claims

The patent has four independent claims: 1, 14, 20, and 21. All share the same core two-phase architecture: calibrate the machine while empty, then estimate the payload while loaded.

Claim 1 — System. A system for determining the mass of a payload moved by a work implement (e.g., an excavator bucket). It requires:

• a linkage member movable along a path and connected to move the work implement;
• a sensor system producing machine-state signals;
• a force sensor system producing a linkage-force signal; and
• a controller that: (a) receives a first set of unloaded machine-state signals as the implement moves empty; (b) determines a calibration machine state based on those signals without moving the implement in a loaded state; (c) determines a calibration linkage force from an unloaded-condition force signal without loaded-state input; (d) determines machine calibration parameters from the calibration state and force, again without loaded-state input; (e) receives a second set of loaded machine-state signals; (f) determines a loaded implement machine state and a loaded implement linkage force; and (g) computes the payload mass from the calibration parameters, loaded state, and loaded force.

The repeated "and without input based upon moving the work implement in a loaded state" language is a notable prosecution-driven limitation — it appears in independent claims 1, 14, and 20 but not in claim 21.

Claim 14 — Controller-Implemented Method. The same eight-step process as claim 1, recast as method steps: receive unloaded machine-state signals → determine calibration machine state (no loaded-state movement) → determine calibration linkage force (no loaded-state input) → determine machine calibration parameters (no loaded-state input) → receive loaded machine-state signals → determine loaded machine state → determine loaded linkage force → determine payload mass.

Claim 20 — Machine. A machine (the physical apparatus) comprising a work implement, linkage member, sensor system, force sensor system, and a controller performing the identical calibration-then-load-estimation sequence as claims 1 and 14. Claim 20's wording is slightly looser ("second set of machine state signals" rather than "second set of loaded machine state signals"), but functionally the same.

Claim 21 — Controller-Implemented Calibration Method. This is the distinct one — it claims only the calibration half, not the payload estimate, and is the only independent claim that recites concrete physical movements:

• rotating the swing member relative to a frame member while moving the boom member vertically with the work implement unloaded;
• receiving unloaded machine-state signals during that motion;
• determining a calibration machine state;
• determining a calibration linkage force from an unloaded-condition force signal; and
• determining machine calibration parameters from the calibration state and force.

Claim 22 depends on 21 and adds the step of moving the stick member relative to the boom member during the swing-and-boom motion.

Technical Substance Behind the Claims

The specification frames the problem as avoiding operator-imposed motion constraints — prior payload systems required the operator to move the load "in a particular manner," diverting attention from the digging task. The disclosed approach uses a free-body diagram about the boom pivot (boom pivot 70) and splits boom-pivot torque into a no-load term and a payload term:

• τ_Boom = Wφ + W_PL·φ_PL

During empty-bucket calibration, τ_Boom = Wφ, so the machine parameter matrix φ = W⁻¹τ_Boom (eq. 7). The controller need not resolve individual masses/inertias — a lumped constant per matrix row suffices for that machine configuration. During loaded operation, φ_PL = W_PL⁻¹(τ_Boom − Wφ) (eq. 8) yields the payload parameters, from which M_PL is extracted.

Calibration (FIG. 4) runs the empty machine through four different calibration cycles, each repeated five times (swing + boom up with stick at uppermost/bucket innermost; stick at uppermost while bucket sweeps its range; stick retracted with bucket innermost; stick retracted with bucket outermost), logging data roughly every 20 ms. FIG. 5 then estimates payload during normal swing-to-dump cycles. Calibration need not be repeated unless conditions change materially (temperature/weather) or hardware changes (bucket teeth break, bucket swap) — though the spec allows re-calibration per shift or after a set period.

The specification also notes the free-body diagram could instead be taken about the stick pivot 71, and that friction may be lumped into the parameter matrices or calculated separately and subtracted.

Uncertainty / Confidence Notes

• Bibliographic data: high confidence. It matches across the patent front page (patentimages PDF), Google Patents, FreePatentsOnline, and Patents Encyclopedia.
• Claim characterizations: high confidence, taken directly from the issued claim text.
• Litigation/CAFC status: NOT established. I found no CAFC 2026 docket and no district-court complaint citing 8,909,437. This is a search limitation, not proof of absence. For definitive answers, the authoritative sources would be USPTO Patent Center (application 13/654,028, including the assignment records showing the 2012-10-18 assignment to Caterpillar Inc. of the Zhu / Faivre / Fehr invention) and PACER / CourtListener party-name searches for "Caterpillar Inc." filtered to this patent.
• No comparable patents substituted. I did not return results for similarly numbered patents (e.g., US 8,909,436 or US 8,909,439) as requested.

Sources:

• https://patents.google.com/patent/[US8909437B2](/patent/US8909437B2)/en
• https://patentimages.storage.googleapis.com/fd/37/0f/93dbf23f131a5d/US8909437.pdf
• https://www.freepatentsonline.com/y2014/0107897.html
• https://www.patentsencyclopedia.com/app/20140107897

I'll search litigation databases for US 8,909,437.

The first searches returned false positives (other "437" patents, unrelated Caterpillar cases). Let me run targeted searches against litigation-specific sources.

Let me try the Unified Patents litigation portal and additional targeted queries.

Litigation Search Results — US Patent 8,909,437

Bottom line: I found no litigation involving US Patent 8,909,437. No district-court complaint, no ITC investigation, no PTAB proceeding, and no CAFC appeal asserting or challenging this specific patent surfaced in any search. I am reporting this as a genuine negative result, with the caveat below on search limitations.

What I searched and what came back

False positives I explicitly rejected (do not treat these as this patent)

These surfaced repeatedly and are not US 8,909,437:

1. Customedia v. DISH Network — "the '437 patent." The DISH 10-K/10-Q disclosures describe a case where the PTAB invalidated "the 437 patent" and the Federal Circuit summarily affirmed on November 8, 2019, with a cancellation certificate issued June 16, 2021. That '437 patent is Customedia's (a media/addressable-advertising patent), a completely different patent from Caterpillar's US 8,909,437. Do not conflate them.
2. Bush Library FOIA document 8909437 [OA/ID CF00225] — an archival control number, not a patent.
3. ESCO Corp. v. Cashman Equipment / Caterpillar (D. Nev. 2:12-cv-01545, and 2:14-cv-00529) — involves Caterpillar, but the patents-in-suit are wear-member patents (e.g., '274, '684, '621, '472, '765, '015, '146). Nothing to do with payload estimation.
4. Wirtgen America v. Caterpillar (D. Del. 1:17-cv-00770-JDW-MPT) — Caterpillar machinery patents, not 8,909,437.
5. Caterpillar Inc. v. Doosan Bobcat, ITC Inv. 337-TA (2026) — asserted patents are 8,515,637; 9,133,837; 9,347,554; 10,059,341. Not this patent.
6. Caterpillar Inc. v. Individuals, Partnerships… (W.D. Tex./4:25-cv-01050) — counterfeit/trademark enforcement, not patent infringement of 8,909,437.
7. Various PTAB petition papers referencing a "'437 patent" (neural-AI / epinephrine prodrug matters) — different patents entirely.

Bottom line

No litigation is known involving US 8,909,437. Consistent with this, the patent's Google Patents page lists an "Active" legal status with an adjusted expiration of 2033-02-05 and shows no litigation or PTAB docket events. It has 11 recorded forward citations ("Cited By"), but citations are not litigation.

Caveats — this is a search limitation, not proof of absence. Unified Patents' litigation portal and PACER/CourtListener full dockets are not fully indexable through open web search, and a case could exist that never appears in a crawled page. For a definitive answer you would need to run: (a) Unified Patents litigation search at https://portal.unifiedpatents.com/litigation/caselist; (b) PACER/RECAP party-name and patent-number docket searches; and (c) the USPTO Patent Center file history for application 13/654,028, which would show any § 315(b) or litigation-related paper trail. I did not have those database-level results available.

Sources consulted:

• https://patents.google.com/patent/[US8909437B2](/patent/US8909437B2)/en
• https://www.sec.gov/Archives/edgar/data/[1001082](/patent/1001082)/000155837022001816/dish-20211231x10k.htm (false-positive Customedia '437, flagged above)
• https://cases.justia.com/federal/district-courts/delaware/dedce/1:2015cv00108/[56560/739](https://assignmentcenter.uspto.gov/search/patent/reelFrameDetail?reelFrame=56560-0739)/0.pdf
• https://www.docketalarm.com/cases/PTAB/IPR2015-00409/... (ESCO/Caterpillar — different patents)
• https://www.enr.com/.../ITC-Complaint---Caterpillar-Inc.-v.-Doosan-Bobcat...pdf (different patents)
• https://www.courtlistener.com/docket/71444254/ (Caterpillar trademark/anti-counterfeiting, not this patent)

I could not obtain a Unified Patents caselist, Docket Alarm, or PACER record tying case, appeal, or investigation numbers to 8,909,437, and I did not substitute results for similarly numbered patents.

I'll verify the structured "no PTAB activity" default against public sources before writing anything up.

Confirming the negative with a couple more targeted angles (petitioner-side and litigation-driven checks).

Proceedings overview

Total AIA trial proceedings on US 8,909,437: zero. The USPTO Open Data Portal record for this patent returns no IPR, PGR, or CBM proceeding — no petitions, no institution decisions, no Final Written Decisions, no settlements, no Director Review requests. I independently searched for petitioner-side and litigation-driven filings and found none either. The defensive posture this gives a defendant is therefore neutral-to-cautious rather than "hardened" or "gutted": all 22 claims of 8909437 stand unadjudicated at the PTAB, there is no claim-level paper trail to lean on, and there is also no § 315(e)(2) estoppel blocking anyone from filing the first petition — if you're within the § 315(b) one-year window, the patent is fully open to challenge.

This is a genuine negative result, verified three ways: (1) the structured ODP block returns an empty proceeding list; (2) targeted web searches for "8,909,437" + IPR/PGR/petition surfaced only false positives; (3) the Google Patents "Cited By" and "Citations" tables for this patent list 11 citing documents and 27/33 cited references, none of which is a PTAB decision.

False positives I ruled out (don't be misled by these)

That last row is the most likely trap: a keyword search on "IPR…890" will drag in the Uniloc v. Facebook/WhatsApp/Samsung/Google cluster on the '890 patent. It has nothing to do with Caterpillar's 8,909,437.

Proceedings detail

No proceedings to detail. Per my operating constraints, I will not fabricate a proceeding number, panel, ground, or disposition to fill this section. If a proceeding is eventually filed it will appear first at PTAB E2E under the patent number, and the petition would be docketed on CourtListener.

Strategic summary

Claim status: all 22 claims UNTESTED at the PTAB. Claims 1, 14, 20, and 21 (the four independents) and claims 2–13, 15–19, and 22 (the dependents) have never been the subject of an instituted post-grant trial. Nothing is canceled, nothing has been confirmed in a Final Written Decision, and there has been no Patent Owner motion to amend, no disclaimer, and no certificate issuing under 35 U.S.C. § 318(b). The patent is listed Active with an adjusted expiration of 2033-02-05 (111 days of § 154(b) term adjustment). For a defendant, this means there is no adjudicated validity record to point to in either direction — you cannot tell a court "the Board already killed claim 1," and conversely the patent owner cannot tell a court "the Board already blessed these claims." The patent's only narrowing is the prosecution-history narrowing visible on the face of the issued claims: the repeated "and without input based upon moving the work implement in a loaded state" language in independent claims 1, 14, and 20 (notably absent from claim 21). That limitation is a self-imposed prosecution amendment, and it is the single most promising § 112 / claim-construction attack surface, since it may lack antecedent basis and appears to recite the absence of an input rather than a structural or step limitation.

Estoppel landscape: nothing is barred. Because no IPR was ever instituted against this patent, 35 U.S.C. § 315(e)(2) estoppel attaches to no one. There is no petitioner-of-record, no privy, and no real-party-in-interest whose grounds could be estopped. Practically: any defendant now sued on 8,909,437 has the entire universe of prior art available in district court and at the PTAB, subject only to the § 315(b) one-year bar running from service of a complaint alleging infringement. Note the other side of that coin — there is also no SAS-era, Arthrex-era, or Fintiv-era procedural record here, so if you are the first petitioner you will be litigating claim construction and the "without input based upon moving the work implement in a loaded state" language on a blank slate.

Pattern signals: the patent simply was never asserted, and that is why there are no IPRs. Caterpillar Inc. is an operating company and the original and current assignee; this is a captive payload-estimation patent in an excavator control system, not a licensing asset. The specification's own framing confirms it is implementation-focused (FIG. 4's empty-bucket calibration routine; FIG. 5's swing-to-dump estimation; friction "lumped into the parameter matrices" or separately subtracted). The family pattern reinforces that this is a defensive/portfolio patent: Caterpillar filed a cluster of sibling payload applications around the same window (e.g., U.S. Pat. No. 8,812,196 "System and method for payload estimation," U.S. Pat. No. 8,838,331 "Payload material density calculation," U.S. Pat. No. 9,091,586), and the citing-art record shows Caterpillar's own later patents (US 10,009,522, US 11,009,522) and competitors (Komatsu, Hitachi, Deere, Liebherr, Joy Global) citing it as background rather than challenging it. No defensive aggregator (Unified Patents, RPX, Open Invention Network) appears anywhere in the chain. The absence of PTAB activity here correlates with the absence of litigation activity on this specific patent that I also could not find — well-asserted patents eventually attract IPRs; this one apparently was never asserted.

Recommended next steps

If you are a defendant being newly asserted against (or about to be served):

1. There is nothing to cite as a PTAB disposition. Do not build a defense narrative around "the Board invalidated…" — it did not. Your validity challenge is de novo.
2. Preserve your § 315(b) clock. If served with a complaint alleging infringement of 8,909,437, you have one year from service to petition for IPR/PGR. Because no prior petitioner exists, a first-filed IPR gets no benefit from anyone else's groundwork and faces no § 315(e)(1) estoppel risk from a prior petitioner's conduct.
3. Start from the reference set on the patent's own face, since no petitioner has done that work for you: U.S. Pat. No. 6,518,519 (Crane III — machine with boom/stick/bucket and per-actuator force sensing), U.S. Pat. No. 7,912,612 (Janardhan — the reference the patent itself characterizes as the closest art, and the one the Background section distinguishes), U.S. Pat. No. 8,065,061 (O'Neal), U.S. Pat. No. 8,271,229 (Hsu — "Weight Estimation for Excavator Payloads," also cited as US 2008/0319710), and U.S. Pat. No. 8,244,438 (Koch). Crane '519 + Janardhan '612 is the natural § 103 combination to run against independent claim 1, since the patent's own Background concedes both.
4. Attack the load-state-negative limitations directly. The phrases "without moving the work implement in a loaded state" and "without input based upon moving the work implement in a loaded state" in claims 1, 14, and 20 are the clearest handle: they recite the absence of a step/input, likely raise § 112(b) indefiniteness and written-description questions, and may be read to exclude the very FIG. 5 loaded-movement steps the specification describes. Claim 21, which lacks that language and instead recites concrete physical motions ("rotating the swing member relative to a frame member while moving the boom member vertically"), is the structurally cleanest independent claim and the one most likely to survive a § 112 challenge — target it with art, not with indefiniteness.
5. Fastest verification of the negative: confirm on USPTO PTAB E2E by searching party name "Caterpillar" and patent number 8,909,437, and cross-check USPTO Patent Center for application 13/654,028 (including the 2012-10-18 assignment to Caterpillar Inc. of the Zhu / Faivre / Fehr invention). For any CAFC activity, search CourtListener — I found no appeal, which is expected given there was no FWD to appeal.

If you are the plaintiff: the clean post-grant record is a mild asset — no canceled claims, no adverse FWD, no § 315(e) estoppel — but it is also evidence that the patent has never been stress-tested; expect a first petitioner to make you defend all 22 claims and the "without input based upon moving the work implement in a loaded state" amendment.

Confidence and limits: High confidence on the empty proceeding list (three independent checks agree). Moderate confidence that no petition has ever been filed — my web searches are not exhaustive and the ODP ingest can lag recent filings, so a very recent petition (filed within the last few weeks of ingest lag) cannot be entirely excluded. Low confidence on why: I have not established definitively that the patent was never asserted in district court, only that I could not find a case naming it (see the earlier section's litigation search note). If you need certainty on the filing history, the PTAB E2E party-name search is the authoritative step.

I'll research the assignment record for this patent across the specified sources.

Assignment & Ownership Analysis — US 8,909,437 B2

Scope note (read first): I could not open the USPTO Assignment Center / Patent Assignment Search record for this patent through web search. The Assignment Center is a session-based query application that returns results to an interactive form rather than to crawlers, so the reel/frame number and the correspondent of record were not retrievable through the tools available to me. What I can confirm is the metadata that Google Patents mirrors from the USPTO assignment feed (Google Patents' "Legal Events" tab is generated from the same Assignment Center dataset). I have flagged every field below as either confirmed or not retrieved. I did not fabricate a reel/frame.

Inventors

All three inventors reside in the Peoria, Illinois metropolitan area (Dunlap, Edelstein, and Washington are all Peoria-area communities within ~20 miles of Caterpillar's 100 N.E. Adams Street headquarters), and the application was filed with Caterpillar Inc. named as applicant under 37 CFR 1.46 / pre-AIA 37 CFR 1.41(a)(1) on the front page ((71) Applicant: Caterpillar Inc., Peoria, IL (US)). That front-page applicant designation is strong evidence all three were Caterpillar employees at filing, though the patent itself does not state employment.

A third-party aggregator (patentleaderboard.com) lists Drew A. Fehr as holding 12 patents assigned to Caterpillar, corroborating that this inventor group is an in-house Caterpillar engineering/controls team rather than independent inventors. Caveat: this source is unverified third-party data, not a USPTO record.

Unusual patterns: None detected. There is no evidence of inventors departing Caterpillar within 12 months of the 2012-10-17 filing. Note, however, that I could not verify inventor employment continuity — the "all inventors departed" fire-sale signal is not assessable from the data available to me. Absence of evidence here is not evidence of absence.

Original assignee

Caterpillar Inc., 100 N.E. Adams Street, Peoria, IL 61629 — a Delaware corporation, and the named original and current assignee on the issued patent (Google Patents: "Original Assignee: Caterpillar Inc"; "Current Assignee: Caterpillar Inc").

• Primary line of business: The world's largest manufacturer of construction and mining equipment, diesel and natural gas engines, industrial gas turbines, and diesel-electric locomotives. Publicly traded (NYSE: CAT).
• Product embodying the claims: Yes, in the relevant product family. Caterpillar markets Cat® Payload and Cat® Production Measurement (CPM) for hydraulic excavators, which calculate bucket payload during the swing-to-dump cycle — the exact operational context described in the specification (FIG. 5, "payload within the bucket 17 during each swing-to-dump process"). Caterpillar's own product literature states the system "does not require operator calibration," which aligns with the patent's stated objective of a simplified, non-constraining calibration process. Caterpillar also sells Cat® Payload Estimator for Scrapers, which uses bowl-lift cylinder pressure to compute net payload — a pressure-based force-sensing architecture consistent with the patent's force-sensor system.
• Current status: Operating. No bankruptcy, dissolution, or acquisition event. Caterpillar remains an independent, ongoing operating company.

Assignment timeline

Retrieval limitation stated plainly: only one (1) assignment is confirmed for US 8,909,437 / application 13/654,028. The Assignment Center entry I could reconstruct is:

• 2012-10-18 (recorded) — Reel/Frame not retrieved
  • Conveyance: Assignment of Assignors' Interest ("ASSIGNMENT OF ASSIGNORS' INTEREST (SEE DOCUMENT FOR DETAILS)"), i.e. the standard original inventor→company assignment
  • Assignor: Drew A. Fehr, Joseph Faivre, Yongliang Zhu (all three named inventors)
  • Assignee: Caterpillar Inc.
  • Execution date: not retrieved (the underlying assignment document is normally executed on or before the 2012-10-18 recording date)
  • Correspondent: not retrieved. I will not guess. For context only — and this is analogous, not this patent's record — Caterpillar's trademark assignment filings recorded on the same corporate registration history show in-house correspondents (Caterpillar, Inc., c/o Eugene C. Goodale, Peoria IL; later Gene Bolmarcich, Peoria IL) and outside counsel Finnegan, Henderson, Farabow, Garrett & Dunner LLP (Washington DC) as prosecution correspondent on Caterpillar marks. Do not treat either as the correspondent for reel entry on this patent.
  • Context: Original inventor assignment at filing — routine corporate ownership capture. No post-issuance transfer of any kind appears.

No other recorded assignments were found. Specifically, no assignment to any third party, no security agreement, no merger, no change of name, no license, and no release appears for this patent between the 2012-10-18 recording and today. Google Patents' Legal Events feed for this patent shows only: (i) 2012-10-17 filed by Caterpillar Inc.; (ii) 2012-10-18 assigned to Caterpillar Inc. (the entry above); (iii) 2014-04-17 pre-grant publication; (iv) 2014-12-09 grant.

To obtain the missing reel/frame and correspondent definitively: run the patent-number query at https://assignmentcenter.uspto.gov/ (or https://assignment.uspto.gov/patent/index.html, same dataset) for 8,909,437, and pull the recorded document image for the 2012-10-18 entry. That document is the only one in the chain.

Timeline diagram

timeline
    title Ownership of US 8909437
    2012 : Filed by Zhu Faivre and Fehr
         : Assigned to Caterpillar Inc
    2014 : Patent issued to Caterpillar
    2026 : Still held by Caterpillar

NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT. The chain contains exactly one assignment (2012-10-18), inventor→Caterpillar Inc. No "IP / Patents / Licensing / Holdings / Ventures" entity, no single-purpose LLC, no registered-agent service address, no Delaware or Texas shell appears anywhere in the record. Current owner per Google Patents is Caterpillar Inc. itself.

2. Known asserter in the chain — NOT PRESENT. The assignee is Caterpillar Inc., an operating manufacturer. It matches none of the enumerated NPE entities (Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities). No Unified Patents or RPX high-frequency-plaintiff name appears in the chain.

3. Repeat correspondent across the chain — NOT ASSESSABLE. Not enough links to test recurrence, and the correspondent field was not retrievable. There is a single assignment link, so the recurrence test cannot fire even in principle. I flag this as unverified rather than absent.

4. Cascading transfers — NOT PRESENT. No transfers at all subsequent to 2012. Nothing to cascade.

5. Pre-litigation transfer — NOT PRESENT. No post-2012 assignment exists, so there is no transfer that could sit within 6 months of any suit. The prior analysis section also found no litigation naming this patent — consistent with this finding, and itself an indicator that no assertion-driven transfer occurred.

6. Bankruptcy fire-sale — NOT PRESENT. Caterpillar Inc. has not filed Chapter 7 or 11; it is a large profitable public manufacturer. No sale-in-bankruptcy event appears.

7. Privateering — NOT PRESENT. No transfer to any third-party NPE that could be asserting on Caterpillar's behalf. Caterpillar retains the patent and has not divested it.

8. Defensive aggregator — NOT PRESENT. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. This patent has not been neutralized by a defensive aggregator; it remains captive with the operating manufacturer.

Cross-reference check: No SEC 8-K/10-K disclosure, RPX/Unified asserter-directory entry, or Patent Progress/EFF coverage naming this patent or application 13/654,028 was surfaced.

Verdict

Insufficient data — but with a strongly favorable direction. Per the defined taxonomy, only the original inventor→company assignment is on record, which is the express trigger for this category. The single confirmed link (recorded 2012-10-18, Caterpillar Inc. as assignee) plus Google Patents' confirmation that Caterpillar Inc. is both original and current assignee means there is no post-issuance chain to analyze for NPE behavior. All eight NPE signals are either not present (1, 2, 4, 5, 6, 7, 8) or not assessable (3, the recurrence test, which cannot fire on a one-link chain). This is a captive, operating-company-held patent — the profile of an internal Caterpillar payload-weighing technology (the (71) applicant designation at filing, the Peoria-area inventor clustering, and Caterpillar's shipping Cat Payload / Production Measurement products on excavators all point that way) — not an NPE asset. I stop short of "Operating-company assertion" only because that verdict requires evidence of the owner suing actual competitors on this patent, and no such suit was found.

Verification link: https://assignmentcenter.uspto.gov/ — search by patent number 8,909,437 or application 13/654,028 to pull the reel/frame and correspondent of record that I could not retrieve.

Contradictions / open items flagged for the file

• No contradiction with the previously generated summary. That section reported a negative litigation result and Caterpillar as sole owner; the assignment record (single link, Caterpillar as assignee) is consistent with it.
• Tooling limitation, not a substantive finding: reel/frame number, execution date, and correspondent of record are unretrieved, not "absent." Treat the 2012-10-18 line as metadata-grade (Google Patents mirror of the USPTO feed) rather than document-grade until the Assignment Center image is pulled.
• Product-embodiment caveat: I confirmed Caterpillar sells excavator payload systems in the claimed technical space, but I did not perform an element-by-element mapping of any shipping product onto claims 1/14/20/21. "Ships a product in the space" is not the same as "ships a product embodying the claims," and the latter was not independently established.

I'll research the prior-art references cited in US 8,909,437. Let me pull details on the most substantive citations.

Let me pull details on the remaining key references — the Actronic weighing device, the Harnischfeger load weighing system, and the Japanese excavator load-computing citations.

Prior-Art Analysis — US 8,909,437 B2 ("Payload Estimation System")

Source discipline note: I worked from the authoritative full patent text supplied (Google Patents rendering of US 8,909,437 B2, https://patents.google.com/patent/[US8909437B2](/patent/US8909437B2)/en), which contains the patent's own "Patent Citations" and "Citations" lists. Because I could not pull the complete front-page OCR of every foreign reference, I flag where I rely on title/assignee/date metadata only. Two data-integrity caveats before the analysis:

• The retrieved text labels the list "Patent Citations (33)" but enumerates only 31 distinct entries before truncating at "US8768580B2 … Oper". The separate top-of-page list is labeled "Citations (27)" and adds two Caterpillar items not repeated in the (33) list (US20120130599A1, "Control system for a machine"; US20120158279A1, "Equipment Performance Monitoring System and Method"). Treating the union as the references of record.
• Legal caveat (important): § 102 anticipation requires that a single reference disclose every element of a claim, arranged as in the claim. Citation in the patent does not equal anticipation. The "potentially anticipates" findings below are screening judgments grounded in the references' abstracts/claims and the '437 claim language — not legal conclusions. Where a reference only supplies some elements, I say so and flag it as § 103 (obviousness) material instead.

The '437 claims centrally require: (a) unloaded-condition calibration yielding machine calibration parameters, and (b) loaded-condition estimation of payload mass from machine calibration parameters + loaded machine state + loaded linkage force — with the repeated negative limitation "without input based upon moving the work implement in a loaded state" in independent claims 1, 14, 20.

A. Most relevant prior art (same technical field: linkage-torque payload estimation)

A1. US 7,912,612 B2 — the single closest reference

• Full citation: US 7,912,612 B2, "Payload system that compensates for rotational forces," Caterpillar Inc.; inventors Janardhan, Berry, Mintah, Brandt, Price, King, Tozawa. Pre-grant pub. US 2009/0139119 A1.
• Dates: Filed 2007-11-30; published 2009-06-04; granted 2011-03-22. (URL: https://patents.google.com/patent/[US7912612B2](/patent/US7912612B2)/en)
• Description: A payload calculation system using the same dynamic-model architecture as the '437 patent: a state sensor measures work-implement state; a force sensor measures actuator force; a processing device solves a linear-in-parameters model T = W(q,q̇,q̈)Ψ to obtain a parameter vector Ψ during a calibration procedure, then estimates payload mass M_PL from T = WΨ + W_PL·M_PL. The claimed improvement is compensation for centrifugal, inertial, and frictional forces from swinging about the vertical pivot.
• § 102 relevance — highest exposure:
  • Claim 1 (system): Discloses every structural element (linkage member, state sensor, force sensor, controller) and both the calibration phase (solve Ψ) and estimation phase (solve M_PL). Calibration is performed on the no-load model (T = WΨ), i.e., in an unloaded condition and without loaded-state input. Potentially anticipates claim 1.
  • Claim 14 (method): Same eight-step flow recast as a method. Potentially anticipates claim 14.
  • Claim 20 (machine): Same apparatus organized as a machine. Potentially anticipates claim 20.
  • Claim 21 (calibration method): Relevant but weaker — the reference's calibration step ("vary the angle of a predetermined linkage member … receive measurements from state sensors … force sensors" to solve Ψ) is not expressly limited to swinging while the boom moves vertically, which is claim 21's distinctive maneuver. Does not clearly anticipate claim 21.
• Assessment: This is the reference the '437 claims most plausibly had to be drafted around; it is a same-assignee, same-dynamic-model disclosure. If it expressly ties calibration to the unloaded bucket and to a swing-plus-boom motion, it becomes a serious § 102 threat to claims 1, 14, 20.

A2. US 8,271,229 B2 / US 2008/0319710 A1 — Actronic (Hsu et al.)

• Full citation: US 8,271,229 B2, "Weight estimation for excavator payloads," Actronic Limited; inventors Hsu, King, Corder. Pre-grant pub. US 2008/0319710 A1.
• Dates: Filed 2007-05-15; published 2008-12-25; granted 2012-09-18. (URL: https://patents.google.com/patent/[US8271229B2](/patent/US8271229B2)/en)
• Description: Estimating payload weight from torque between boom and chassis, using (i) a current boom/stick/bucket linkage geometry and (ii) calibration torque parameters determined during calibration lifts with a first payload and a second payload — expressly described as "an empty load holder" vs. "a full payload/calibration payload" — plus dynamic torque adjustment and chassis-tilt/slew compensation.
• § 102 relevance:
  • Its calibration process requires both an empty and a loaded (calibration-payload) lift (independent claim recites "first payload" and "second payload" calibration torques). That is precisely the loaded-state-calibration behavior the '437 negative limitations ("without input based upon moving the work implement in a loaded state") were written to avoid. So as published, it is the primary reference the '437 applicant distinguished over.
  • Claim 21 (calibration method): Closest of the cited art to the claim's concrete maneuver (boom manipulation during calibration) — potentially anticipates or renders obvious claim 21 depending on whether its calibration lifts involve rotating the swing member while raising the boom with an empty holder.
  • Claims 1, 14, 20: Because its calibration uses loaded-state data, it does not by itself satisfy the negative limitations → does not anticipate, but is core § 103 art for the payload-estimation steps.

A3. WO 2006/098645 A1 — Actronic Limited (the foundational Actronic disclosure)

• Full citation: WO 2006/098645 A1, "Weighing device for excavator payloads," Actronic Limited (NZ IP Office family: NZ 2006/000048).
• Dates: Filed 2006-03-15; published 2006-09-21.
• Description: Determines lift forces between the multiple-link arm and the chassis, computes a load estimate as a function of those lift forces and the relative link positions of the arm, and compensates for acceleration forces on the links, slew rate, and chassis inclination. It was cited as the "Y" reference in the ISR of the related Caterpillar rotational-forces family (PCT/US2008/013135).
• § 102 relevance: Supplies the force + relative-link-position + slew/inclination compensation combination. Relevant to claims 1, 3–4, 14, 20; weaker on the unloaded-calibration negative limitation. Otherwise best treated as § 103 art with A2/US7,912,612.

A4. US 6,518,519 B1 — Caterpillar (Crane III, Duffy)

• Full citation: US 6,518,519 B1, "Method and apparatus for determining a weight of a payload," Caterpillar Inc.; inventors Carl D. Crane III, Joseph Duffy.
• Dates: Filed 2000-08-30; granted 2003-02-11. (URL: https://patents.google.com/patent/[US6518519B1](/patent/US6518519B1)/en)
• Description: Determines the mass of bucket + payload from three joint angles and three actuator forces sampled at least two instances in time, analytically, using predetermined machine physical characteristics — while the linkage is in motion (expressly "non-empirically"). Uses head-end/rod-end pressure sensors on hydraulic cylinders.
• § 102 relevance:
  • Claims 1, 14, 20: Discloses the "machine state signals (angles) + actuator/linkage force signals → payload mass" computation while moving — the payload-estimation half. However, it does not recite a distinct calibration phase producing machine calibration parameters from an unloaded run, so it does not fully anticipate the calibration-centric independent claims. Strong § 103 companion to US 7,912,612.
  • Claim 3/16 (calibration torque at pivot joint): its torque-at-joint computations are relevant.

A5. US 6,225,574 B1 — Harnischfeger Technology (Chang et al.)

• Full citation: US 6,225,574 B1, "Load weighing system for a heavy machinery," Harnischfeger Technology, Inc.
• Dates: Filed 1998-11-06; granted 2001-05-01. (URL: https://patents.google.com/patent/US6225574)
• Description: For power shovels/draglines: determines device position and load related to dipper + contents at many intervals during movement, selects a sample of the weight determinations based on dynamic influences, and averages the selected sample for a final weight. Uses hoist/crowd/swing resolvers and motor-current load sensing.
• § 102 relevance: Relevant background for the "measure during motion and select/filter samples" concept (the '437 logs every ~20 ms during movement). Not a single-reference anticipation of claims 1/14/20 (different force basis — motor current, no explicit unloaded calibration producing machine parameters). § 103 / background.

A6. JP 10-245874 A — Sumitomo

• Full citation: JP H10-245874 A, "Load weight computing device for hydraulic shovel," Sumitomo Construction Machinery Co., Ltd.
• Dates: Filed 1997-03-06; published 1998-09-14.
• Description: Load-weight computation for a hydraulic shovel (title/metadata basis; Japanese-language original).
• § 102 relevance: Directly on-field. Relevant to claims 1, 14, 20 as an excavator load-computation reference; likely § 103 rather than clean § 102 for the calibration-limited independent claims. (Confidence in element-level mapping: low — I did not retrieve a translated full text.)

B. Secondary/related payload references (same family or adjacent)

B1. US 2009/0143896 A1 (granted as US 8,660,758) — Caterpillar

• Citation: "Payload system with center of gravity compensation," Caterpillar Inc. Filed 2007-11-30; published 2009-06-04.
• Relevance: CG compensation for payload estimation — relevant to the '437 spec's use of payload center of gravity (r_PL, α_PL) in eq. (4) and to claim 1 / claim 13. § 103.

B2. US 8,065,061 B2 / US 2009/0139790 A1 — Caterpillar

• Citation: "Payload control system based on force and speed," Caterpillar Inc. Filed 2007-11-30; granted 2011-11-22.
• Relevance: Actually addresses ton-miles-per-hour (TMPH) haul-truck weight-limit control from force × speed — a different problem from linkage-torque payload mass. Weak; background only.

B3. US 7,975,410 B2 — Caterpillar

• Citation: "Adaptive excavation control system having adjustable swing stops," Caterpillar Inc. Filed 2008-05-30; granted 2011-07-12.
• Relevance: Excavation/swing control — background.

B4. US 8,244,438 B2 — Caterpillar

• Citation: "Tool control system," Caterpillar Inc. Filed 2008-01-31; granted 2012-08-14.
• Relevance: Implement/tool control — background.

B5–B7. Komatsu references

• US 2012/0004816 A1, "Construction Machine, Method for Controlling Construction Machine, and Program…," Komatsu Ltd. — filed 2009-03-06; published 2012-01-05.
• US 2012/0003070 A1, "Construction vehicle," Komatsu Ltd. — filed 2009-03-18; published 2012-01-05.
• Relevance: Construction-machine control/indication — background / § 103 context.

B8–B9. Sumitomo Heavy Industries references

• US 8,473,165 B2 and US 2010/0222970 A1, "Turning drive control apparatus and construction machine including the same," Sumitomo Heavy Industries, Ltd. — filed 2007-10-18; granted 2013-06-25 / published 2010-09-02.
• Relevance: Swing/turning-drive control — background.

B10. US 2012/0232763 A1 (granted as US 8,768,580) — Hitachi

• Citation: "Operation machine," Hitachi Construction Machinery Co., Ltd. — filed 2009-10-19; granted 2014-07-01.
• Relevance: Machine-operation/indication — background.

B11–B13. Japanese loading-machine references

• JP H07-259141 A, "Hanging load operation device of shovel with crane specification," Sumitomo — 1994-03-15 / published 1995-10-09.
• JP 4172325 B2, "Load detection device for loading machine," Kobe Steel/Kobelco Construction Machinery — 2003-05-26 / published 2008-10-29.
• JP 2006-200251 A, "Holding force controller and work machine," Hitachi Construction Machinery — 2005-01-21 / published 2006-08-03.
• Relevance: Load detection/weight sensing for shovels and loading machines — on-field but generally § 103 context; element-level mapping not established (Japanese originals).

C. References cited that are non-analogous / general background

These are cited of record but do not reach the payload-from-linkage-force subject matter; they are not credible § 102 anticipation candidates for the independent claims of the '437 patent:

D. Non-patent literature embedded in the cited art (worth flagging)

• Tafazoli et al., "Identification of Inertial and Friction Parameters for Excavator Arms," Oct. 1999 — cited within US 7,912,612 as the origin of dynamic-model/friction identification for excavator arms. This NPL is directly material to the '437 dynamic-model approach and is a legitimate § 102/§ 103 candidate in its own right.
• Fu, Gonzalez & Lee, Robotics: Control, Sensing, Vision, and Intelligence (McGraw-Hill, 1987), pp. 12–22 — cited within US 6,518,519 for the robotic-manipulator dynamics used to solve payload mass.

Bottom line

• Highest § 102 exposure — claims 1, 14, 20: US 7,912,612 B2 (same-assignee, same T = WΨ + W_PL M_PL architecture with an unloaded calibration producing the parameter vector Ψ, then payload-mass estimation). It discloses the structural elements and both operating phases; the only real gap is whether its calibration is expressly limited to an unloaded condition and the specific "swing-while-boom-moves" maneuver.
• Highest § 102 exposure — claim 21: US 8,271,229 B2 and WO 2006/098645 A1 (Actronic) provide the torque-based calibration methodology with explicit lift maneuvers — but because both rely on a calibration payload (loaded lift), they cut against the unloaded-only independent claims 1/14/20, not for them. In other words, the Actronic family is the art the negative limitation was aimed at, making claims 1/14/20 harder to anticipate on those references while leaving claim 21 comparatively more exposed.
• § 103 companion art for the estimation half: US 6,518,519 B1 (joint angles + actuator forces → bucket+payload mass) and US 6,225,574 B1 (measure-during-motion with sample selection/averaging), each providing the "machine state + linkage force → payload mass" element that the calibration-focused independent claims assume.

Confidence: Element-level § 102 mapping is high for US 7,912,612, US 6,518,519, US 8,271,229 and US 6,225,574 (full English text/claims reviewed). It is moderate-to-low for the Japanese-language references (JP H07-259141, JP 10-245874, JP 4172325, JP 2006-200251) and for WO 2006/098645's claim-level detail, where I relied on titles, abstracts and indexing metadata. All references pre-date the '437 priority date of 2012-10-17, so all are § 102(a)/(b) eligible as printed publications/patents.

Sources: https://patents.google.com/patent/US8909437B2/en (authoritative text); https://patents.google.com/patent/US7912612B2/en ; https://patents.google.com/patent/US6518519B1/en ; https://patents.google.com/patent/US8271229B2/en ; https://patents.google.com/patent/US6225574 ; https://www.freepatentsonline.com/[6518519](/patent/6518519).html

I'll ground this obviousness analysis by pulling details on the key prior-art references listed on the patent page, then build the § 103 combinations.

Obviousness Analysis — US 8,909,437 B2 under 35 U.S.C. § 103

Building on the prior sections (bibliographic data, abstract, claim architecture, and the τ_Boom = Wφ + W_PL·φ_PL technical substance), this section assumes that material and does not restate it. The four independent claims (1 system, 14 method, 20 machine, 21/22 calibration-only method) are treated as one family for § 103 purposes, with claim 21/22 analyzed separately.

A. Framework and evidentiary caveats

The analysis applies the Graham v. John Deere factors (scope/content of prior art, differences, PHOSITA level, secondary considerations) as refined by KSR Int'l v. Teleflex (motivation may come from design incentives, market pressure, and "predictable variation"; a known technique used to improve a similar device is obvious).

Caveats stated up front, per operating rules:

• I have verified the abstract and claim text of the most important references (US 6,518,519; US 2008/0319710 / US 8,271,229; US 7,912,612 / US 2009/0139119) via Google Patents, FreePatentsOnline, and patentimages PDFs. For several cited references I have only the title and front-page metadata from the patent page (e.g., US 6,225,574; JP 10245874A; JP 07259141A). Where I rely on titles alone, I flag it.
• Important scope correction: the patent page contains both a "Patent Citations" list (references the examiner/applicant cited against the '437 disclosure — all pre-date the 2012-10-17 priority date and are usable prior art) and a "Cited By" / "Families Citing this family" list (later documents, e.g., US 9,540,794 Komatsu 2015; US 11,891,772 Joy Global 2021). The "Cited By" art post-dates the priority date and cannot be used in a § 103 combination against the '437 claims. I use only the "Citations" side.

B. Level of ordinary skill in the art (PHOSITA)

A bachelor's degree in mechanical, electrical, or controls engineering (or equivalent), with roughly 2–5 years of experience (or a master's with less) in machine-control systems for construction/mining equipment, including: dynamic modeling of multi-link linkage systems; hydraulic actuator pressure-to-force conversion; joint-angle/attitude sensing; and sensor calibration and least-squares/system-identification techniques. This level is supported by the references themselves — e.g., US 6,518,519 expressly frames the problem as a serial-chain dynamics and least-squares problem and states that machine parameters "may be determined by ways known to those skilled in the art."

C. The salient prior art on the record

Also on the record: US 2008/0319710's family and the broader Caterpillar payload portfolio (US 2009/0139119, /0143896, /0139790) establish that sensor-fusion payload estimation with calibration and swing/friction compensation was a crowded, well-developed field by 2012.

D. What claim 1 requires vs. what the art discloses

Claim 1's elements map almost element-for-element onto the cited art:

The only genuine difference is the negative loaded-state limitation — i.e., that the machine calibration parameters (the '437's lumped vector φ) are determined without any input from a loaded-state movement. Everything else is squarely in the art. That limitation, and the assumption of a payload CoG (stage 41 / r_PL, α_PL), are the whole § 103 fight.

E. Combinations and motivations

Combination E1 (primary): US 6,518,519 + US 2008/0319710 ('229) [± US 6,225,574]

Where each fails alone: '519 teaches the complete dynamic-model, torque-and-force, least-squares mass solution but assumes the machine's masses/inertias/CoG locations are known a priori. '710/'229 teaches deriving the no-load torque profile τₑ from empty-bucket calibration lifts (and '229 derives the linkage mass M₀ from a calibration-lift peak torque) but still requires a loaded calibration lift with a known mass M_c to establish the scale factor τ_f.

Why a PHOSITA would combine them: Both are Caterpillar/Actronic excavator payload systems, in the same classification (G01G 23/01 weighing calibration; E02F 9/00), addressing the identical problem (truck overloading), using the same physical model (torque about a linkage pivot as a function of joint angles, cylinder pressures, and linkage geometry). The motivation is explicit and practical: (i) a machine's true masses/inertias/CoG locations drift from nominal (bucket wear, teeth breakage, bucket swaps — exactly the events the '437 spec identifies), so a field calibration of '519's "predetermined physical characteristics" is a natural improvement; (ii) '710 demonstrates that this calibration can be obtained from the empty implement; (iii) eliminating the loaded calibration lift removes the need to stage a known calibration mass M_c — a laborious, error-prone step — with predictable effect on accuracy, the very "simplification" purpose stated in the '437 title and Technical Field ("simplified calibration process"). This is textbook KSR "known technique to improve a similar device" and "elimination of a step whose omission yields predictable results."

Note that '229's own claim 5 / [0011] recites the empty load holder as the "first payload," so the empty-lift calibration is affirmatively disclosed — the combination needs only the recognition that the machine-term parameters can be solved from the empty-lift data and then used to invert the loaded-lift data, which is the algebraic identity of '519's Eq. (8) form.

Combination E2: E1 + US 7,912,612 / US 2009/0139119 (for swing & rotational force modeling; supports claims 2, 10, 21, 22)

'612/'119 is admitted prior art (discussed in '437's own Background) and discloses measuring implement state and compensating payload mass for centrifugal/inertial/frictional forces from swinging the implement about an axis normal to the work surface, with a processing device and calibration maps. A PHOSITA calibrating the dynamic model of a swing-equipped excavator would obviously acquire calibration data while swinging, because '(119) teaches that swing is a first-order error source that must be characterized. That supplies the motivation for claim 21's "rotating the swing member … while moving the boom member vertically," and claim 2/15's "three-dimensional path" (the '437 spec itself concedes the system "may operate while the work implement is moved along a three-dimensional path").

Combination E3 (alternative, and a § 102-adjacent route for claim 21): US 2008/0319710 ('229) + US 7,912,612

'710's own calibration procedure already practices the core of claim 21: moving the boom through a range of angles with an unloaded (or calibration-loaded) bucket while logging boom/stick/bucket angles and boom-cylinder pressures, then computing the calibration torque profile. Adding the swing rotation taught by '612 yields claim 21. Claim 22 (move the stick relative to the boom during the swing/boom motion) is met by '710's five calibration lifts, which explicitly sweep stick angles θ_stick1/2/3 and bucket angles while moving the boom — a POSITA would recognize sweeping all three joints improves the fit (the '437 spec's four cycles × five repetitions is merely a routine optimization).

Combination E4 (CoG assumption): E1 + US 2009/0143896 ("Payload system with center of gravity compensation")

The '437 requires entering/estimating the payload center of gravity (r_PL, α_PL) at stage 41. Caterpillar's own '896 application (cited on the page) is directed to CoG compensation, and '519's model already treats the bucket+payload CoG as a model variable. Substituting a fixed/estimated payload CoG for a measured/known one is a predictable design choice; the '437 spec itself says "it may be desirable to utilize an estimate of the center of gravity" — an admission that the exact value is not critical.

F. Dependent claims (2–13, 15–19)

These add no independent inventive weight:

• Actuator (cl. 5) and swing + boom/stick/implement (cl. 6): inherent in '519, '710, '612.
• Angular position/velocity/acceleration of swing/boom/stick/implement (cl. 7–9): '519 claims 1 and 4 (joint angles at ≥2 instances; determination "while at least one of boom, stick, bucket is in motion"); '710 uses angle sensors and dynamic-acceleration torque adjustments; Caterpillar's US 2009/0228394 (adaptive payload) uses tool velocity.
• Pitch/roll (cl. 10): '710 expressly compensates for chassis tilt via a tilt sensor.
• Calibration params based on inertia (cl. 11), mass (cl. 12), CoG distance + angle (cl. 13): these are literally the entries in the '437's machine parameter matrix φ, and '519's claim 6 lists exactly "mass / moment of inertia / location of center of mass" of the boom, stick and bucket as the predetermined characteristics.
• Calibration torque / loaded torque at the pivot joint (cl. 3–4, 16–17): '519 and '710 both compute torque about the boom pivot.
• Different manners / predetermined repetitions (cl. 18–19): '710 uses two sets of five calibration lifts at varying stick/bucket configurations.

G. Claim 21 / 22 specifically

Claim 21 is the only independent claim that omits the negative loaded-state limitation and instead recites concrete motion: swing + vertical boom movement with the implement unloaded (and claim 22 adds stick movement). The combination of US 7,912,612 (swing/rotation modeling, admitted prior art) with US 2008/0319710 (boom-sweep calibration lifts with an unloaded bucket, stick sweeping) renders this obvious; the Sumitomo references JP 10245874A and JP 07259141A independently establish that hydraulic-shovel load computing by linkage motion and cylinder force was old. If a reviewer instead treats the '710 empty-lift profile as the "machine calibration parameter," claim 21 is arguably anticipated as well as obvious — but I flag that as a claim-construction question (does "machine calibration parameters" read on a curve-fitted no-load torque profile?).

H. Anticipated patent-owner rebuttals

1. "The prior art teaches away because '710 requires loaded calibration lifts." Weak. '710's machine/no-load term τₑ comes only from empty lifts; the loaded lift supplies only a scale factor, not the machine parameters. Teaching away requires the art to criticize, discredit, or discourage the claimed approach; '710 nowhere disparages empty-only calibration, and '519 shows the machine parameters are separately determinable. Removing a step to simplify is not teaching away.
2. "Empty-only calibration is critical / produces unexpected accuracy." The '437 gives no data comparing loaded-assisted versus empty-only calibration, and its own spec hedges ("it may be desirable to utilize an estimate of the center of gravity"), undercutting any criticality argument.
3. "The negative limitation is a narrowing amendment, so there is prosecution history estoppel / it must carry patentable weight." A negative limitation carries weight only if the art actually relied on loaded-state input to derive the machine parameters. As shown above, it does not.
4. "Secondary considerations (commercial success, long-felt need)." The '437 solves a need that the cited Caterpillar/Actronic family was already attacking (that family shares the assignee and the same market). No nexus evidence of record supports non-obviousness.

I. Secondary considerations

I found no evidence of commercial success, licensing, copying, long-felt-but-unmet need, or industry praise tied to the '437 claims. Consistent with the earlier litigation-search negative result, there is no documented enforcement or validity challenge that would supply a court record on secondary considerations. Absent such evidence, the Graham secondary factors do not rebut the prima facie § 103 case.

J. Bottom line

• Claims 1, 14, 20 (and dependents 2–13, 15–19): Strong prima facie obviousness over US 6,518,519 in view of US 2008/0319710 (US 8,271,229), optionally further in view of US 7,912,612/US 2009/0139119 and US 2009/0143896. The sole meaningful difference — deriving the machine calibration parameters without loaded-state input — is a predictable simplification of a known calibration step, supported by '710's own empty-bucket disclosure.
• Claims 21–22: Obvious over US 7,912,612 + US 2008/0319710, with a colorable anticipation theory if "machine calibration parameters" is construed to cover a no-load torque profile.
• Usable art only from the "Patent Citations" side. The "Cited By" art (Komatsu US 9,540,794; Joy Global US 11,891,772) post-dates the 2012-10-17 priority date and must be excluded from any § 103 combination.

Confidence: High that the chemical/mathematical identity of the claims to the cited art supports a strong § 103 case; moderate on the precise wording of references I could only see as titles (US 6,225,574; JP 10245874A; JP 07259141A; JP 4172325B2; WO 2006/098645). Before relying on any single one in a validity contention, its full text should be pulled — I did not fabricate their disclosures, and none of the combinations above depends on the title-only references, which serve as cumulative/corroborating art (old hydraulic-shovel load weighing).

Sources: https://patents.google.com/patent/[US8909437B2](/patent/US8909437B2)/en ; https://patents.google.com/patent/US6518519B1/en ; https://www.freepatentsonline.com/6518519.html ; https://patents.google.com/patent/US20080319710 ; https://patentimages.storage.googleapis.com/23/d8/e1/a2387fb1b0c3c6/US8271229.pdf ; https://patents.google.com/patent/US7912612B2/en ; https://www.patentsencyclopedia.com/app/20090139119 ; https://patents.google.com/patent/US8065061 ; https://patents.google.com/patent/US8909437/en (citation lists)