US 3422610

I'll run the requested searches, then summarize against the authoritative patent text provided.

Let me run a few more targeted searches to check for any litigation or CAFC activity on this exact number.

Search results — scope and caveats first

Searches run: US patent 3422610 Corn topper; CAFC 2026 docket patent 3422610; "3,422,610" patent lawsuit OR litigation OR CAFC; USPTO PatentCenter 3422610 Wetherell corn topper assignee.

What I found (and did not find):

• No CAFC 2026 docket activity. Nothing in the search results links U.S. Patent No. 3,422,610 to any Federal Circuit appeal, PTAB proceeding, or 2026 litigation. This is consistent with the record: the patent's anticipated expiration was 1986-01-21 (Google Patents status: "Expired – Lifetime"). I could not directly query the CAFC docket or USPTO PatentCenter — I used open web search, so I cannot rule out a docket entry with certainty, but there is no evidence of any.
• Distractors returned by search (do NOT confuse with US 3,422,610):
  • DE 3422610 A1 — a German document with a coincidentally similar number, appearing in the search-hit list of JP2007537177A. Unrelated.
  • US 3,425,198 — a different U.S. "Corn-Topper" (harvester-mounted, snap-unit frame-pipe design). Unrelated but similar subject matter.
  • US 3,646,733 ("Side flail mower," Clapsaddle) — this one cites 3,422,610 as prior art ("3422610 | CORN TOPPER | 1969-01-21 | Wetherell"), confirming the patent's bibliographic data.
  • US 5,013,503 / US 3,762,982 / US 3,662,526 / FR 2,402,395 — these are the cited-by references, not the patent itself.

Authority note: The summary below is drawn from the authoritative full text supplied in the prompt (Google Patents, US3422610A, fetched 2026-10-01), which I treat as controlling over any conflicting search snippet.

US Patent 3,422,610 — "Corn topper"

Abstract (as printed in the patent)

"This invention relates to an attachment for a tractor which severs the tops from two rows of standing corn simultaneously. A horizontally extending arm carrying the cutters is supported by four members pivotally connected to each other in the form of a parallelogram, one of said members being fixed to the tractor and the arm being supported on the member parallel thereto. A hydraulic cylinder and piston combination is connected to move the parallelogram members relative to one another to raise and lower the arm while maintaining it in the horizontal position."

Plain-language overview of the independent claims

Claim 1 (narrower — parallelogram + hydraulic cylinder/piston)
A corn-top severing attachment combined with a vehicle. It has:

1. a mounting structure that attaches the device to the vehicle;
2. a horizontal arm carrying cutters that sever the tops of at least two rows of corn at once, supported only at its inner end (cantilevered) by that mounting structure, so the arm sticks out sideways from the vehicle;
3. the arm positioned so every cut is at the same height above the ground plane defined by the vehicle's ground-contact points;
4. height adjustment so all cuts can be made at any of several different heights above that plane;
5. the mounting structure being a four-member parallelogram linkage — one member fixed to the vehicle, the other three free to pivot — with the arm carried on the parallelogram member parallel to the fixed member (which is what keeps the arm level as it rises and falls); and
6. a hydraulic cylinder-and-piston acting between the linkage members (cylinder on one member, piston on another member directly connected to it), powered by fluid controlled and supplied from the vehicle.

Claim 2 (broader — parallelogram only, no hydraulic limitation)
A corn topping device combined with a vehicle, in which:

1. the supporting structure is a four-member pivoted parallelogram, one member fixed relative to the vehicle and the other three free to move;
2. it carries an arm whose cutters sever the tops of at least two rows simultaneously, the arm supported solely on the parallelogram member parallel to the fixed member;
3. in its normal operating position the arm extends laterally outward from the vehicle and holds the cutters so all cuts are at substantially the same height above the vehicle's ground plane, selectable among a plurality of heights.

Key distinction: Claim 2 is the broader claim (it does not require the hydraulic cylinder/piston or the "solely adjacent its inner end" language), while Claim 1 adds the hydraulic actuator and the specific cantilevered mounting. Both independent claims require the parallelogram level-maintaining linkage and simultaneous multi-row (at least two rows) topping.

Dependent-claim highlights (all depend from claim 2, except where noted): a shear-pin pivot that holds the arm in operating position against cornstalk forces but yields to immovable objects like trees (claims 3–9); road-travel positioning parallel to the vehicle's longitudinal axis (claims 7, 13); diverging guide fingers and guide rods with a threaded-burr/nut mounting (claims 10–11); sole support at the arm's inner end (claim 12); hydraulically powered raise/lower (claims 14–16); and hydraulically driven severing means, either a shear-type sickle or a rotary cutter (claims 17–19).

Uncertainty / confidence notes

• Assignee: I have no authoritative record of a corporate assignee. Both the original and current assignee fields indicate an individual (the inventor, Dean Wetherell). I cannot confirm whether any assignment was ever recorded at the USPTO, as I did not directly query the USPTO Assignment database.
• Inventor details: The only inventor of record is Dean Wetherell of Osage, Iowa 50461. No co-inventors are listed.
• Legal status: The patent is long expired (anticipated expiration 1986-01-21). Therefore, the absence of CAFC 2026 docket activity is expected; the patent cannot be asserted now.
• The claim text in the source OCR contains minor typographical artifacts (e.g., "a device is described" in claim 3, and a duplicated clause in claim 1); I have paraphrased substance rather than reproducing those artifacts.

I'll search for litigation involving US patent 3,422,610 across patent litigation sources.

Let me search more targeted litigation databases.

Let me check the Unified Patents portal and other litigation databases directly.

Litigation Search Results: US Patent 3,422,610 ("Corn Topper")

No litigation involving US Patent 3,422,610 was identified.

Search performed

I ran queries against publicly indexed litigation-related content, including the Unified Patents litigation/PTAB portal (portal.unifiedpatents.com), CourtListener, Docket Alarm, and general web/litigation aggregators, using the literal identifiers "3422610," "3,422,610," and the patent title/inventor ("Corn topper," "Dean Wetherell"). I also reviewed the patent's own front-page "References Cited" and "Cited By" records.

Results

Corroborating context from the patent record

The absence of litigation is consistent with the patent's bibliographic profile:

• Single individual owner. The patent issued to inventor Dean Wetherell (Osage, Iowa 50461) with "Individual" as both original and current assignee — no corporate assertion entity or large portfolio holder.
• Expired. Google Patents lists the status as "Expired – Lifetime," with an anticipated expiration date of 1986-01-21 (17 years from the 1969-01-21 grant under the law then in force). The patent has been off-term for roughly four decades.
• Field and vintage. It is a 1965-filed mechanical farm-implement (corn topper) patent classified in A01D47/00. Its citation trail is limited to three examiner-cited prior-art references (Dunn et al. US 2,729,044; Ackermann US 3,025,653; Fogels et al. US 3,325,982) and a handful of later-citing patents (e.g., US 3,646,733; US 3,662,526; US 3,769,782; FR 2402395; US 5,014,503) — none of which reflect or imply litigation activity.

Important caveats

1. Coverage limitations. District-court and CAFC dockets are not fully and freely indexed on the open web; older cases (particularly from the 1969–1986 term and small individual-owner suits) may not appear in the sources I could reach. My conclusion is limited to the sources searched.
2. Search-result contamination. Queries for the bare string "3422610" returned unrelated documents (e.g., German patent DE 3422610 A1 — a BASF amine-manufacturing application — and a French legal-notice URL), none of which relate to US 3,422,610. I did not treat those as hits.
3. No fabrication. I am not asserting that litigation definitively never occurred — only that none is known or discoverable through the sources searched.

Bottom line: Based on available information, there is no known litigation involving US Patent 3,422,610. If you need a negative-infringement/clearance grade searching, the definitive next step would be a paid full-text search of LexisNexis CourtLink, Docket Navigator, or Bloomberg Law Dockets, plus a manual review of the pre-1986 Federal Supplement/F.2d reporters and the USPTO assignment record for any recorded security interests or transfers.

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

Proceedings overview

Zero AIA trial proceedings are on file against US 3,422,610 — no IPRs, no PGRs, no CBMs (0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, 0 institution denials), which means the patent stands today exactly as it issued on 1969-01-21 with all 19 claims intact and completely untested — but the defensive posture this gives a defendant is not "the patent is hardened," it is "the patent is a museum piece": US 3,422,610 expired on 1986-01-21 (17 years from grant under the pre-URAA term rule, no maintenance fees due on a 1965 filing), 26 years before the AIA trial regime took effect on 2012-09-16. There is no live patent to assert, no claim to invalidate, and therefore nothing for the PTAB to have done.

No proceedings to itemize

The structured "PTAB proceedings on file" block drawn from the USPTO Open Data Portal returns an empty set, and that is confirmed by the patent's own bibliographic record. Because the task format calls for a per-proceeding entry, I am stating affirmatively rather than silently omitting:

• Proceedings list: none. No proceeding number exists to report, and I will not manufacture one.
• Web-search corroboration (2026-10-01): targeted searches for "US 3,422,610 / IPR / PTAB," "3,422,610" + petition, and the patent paired with the inventor's name returned no PTAB petition, institution decision, Final Written Decision, termination, or Federal Circuit appeal. Results were unrelated patents (e.g., the '610 patent of a different family in IPR2024-00303; an unrelated DE 3422610 A1 German document). Google Patents' own "Cited By" list shows only five later patent documents (e.g., US 3,646,733; US 5,014,503), not administrative challenges.
• Federal Circuit: no appeal docket number, opinion, or Rule 36 judgment attributable to US 3,422,610 was located. I cannot cite a docket because none surfaced — treat this as an absence of evidence, not proof of a null docket, though for a patent that expired in 1986 the latter is a foregone conclusion.

Strategic summary

Claim status: all 19 claims UNTESTED, and all 19 are expired. US 3,422,610 has two independent claims — claim 1 (parallelogram mount plus hydraulic cylinder/piston with the piston secured to one member and the cylinder to another member directly connected to the piston's member) and claim 2 (parallelogram support alone, with the arm supported on the member parallel to the fixed member) — with claims 3–19 depending from them (claim 3 from claim 2; claims 4–9 from claim 3; claim 10 and claims 12–14 and 17 from claim 2; claim 11 from claim 10; claims 15–16 from claim 14; claims 18–19 from claim 17). Not one of these claims was canceled, confirmed, or even construed in an AIA trial, because the patent entered the public domain on 1986-01-21 — more than a quarter-century before the first IPR was ever filed.

Estoppel landscape: there is none, and it does not matter. With zero petitioners there is no § 315(e)(2) estoppel running against anyone, and no prior-art ground is "used up." That sounds favorable to a challenger until you run the arithmetic: because the patent expired 1986-01-21, § 286's six-year damages lookback reaches back only to 1980-01-21, so any infringement theory depends on conduct from 1980–1986 (and on the patent being enforceable during that window). No sane petitioner files an IPR on an expired patent to defeat a claim that is already time-barred; and an IPR would be an odd vehicle anyway when the correct response to a demand letter is a one-line letter citing the expiration date and the public-domain status of the disclosure.

Pattern signals: none available, and none meaningful. There is no repeat petitioner, no patent-owner appeal history, no defensive aggregator (Unified Patents, RPX, et al.) in the chain — the patent's prosecution-era assignee is listed simply as "Individual," and no post-issuance transfers or litigation are reflected in the structured data. For a 1965-vintage agricultural implement patent filed by an individual inventor and granted in 1969, the absence of PTAB activity is not a strength signal at all. In the normal case I would treat "no IPRs" on a heavily asserted patent as a red flag about the petitioner bar or a quiet settlement. Here the explanation is simpler and dispositive: the patent was dead before the forum existed.

Recommended next steps

• If you are a defendant/recipient of a demand letter citing US 3,422,610: do not file an IPR, PGR, or CBM, and do not budget for invalidity contentions. The complete defense is the face of the patent: filed 1965-08-11, granted 1969-01-21, statutorily expired 1986-01-21. Any assertion of the patent today is baseless on its face. Confirm the expiration date against the USPTO Patent Center record (https://patentcenter.uspto.gov) and the Google Patents bibliographic entry (https://patents.google.com/patent/US3422610/en) before responding.
• If you are evaluating this patent as prior art (its actual remaining relevance — it is a § 102(b)/§ 102(a) printed publication as of its 1969-01-21 grant date, and its 1965 filing date makes it § 102(e) art against later filings), pivot to the prior-art analysis. The disclosure's core teaching — a laterally extending cutter arm carried on a four-bar parallelogram so the arm stays horizontal through raise/lower, with a hydraulic cylinder spanning two parallelogram members, plus a shear-pin-permitted horizontal pivot for obstacle breakaway and a road-travel lock position — is described at length in the specification and is worth citing against later corn-topping and side-mounted mower art. Note the five documents that cite it (US 3,646,733; US 3,662,526; US 3,769,782; FR 2,402,395 A1; US 5,014,503), which may help you trace the art lineage.
• If you are looking for proceedings against a similarly numbered but different patent: check that you are not conflating this patent with U.S. Patent No. 8,190,610 (Databricks v. R2 Solutions, IPR2024-00303) or with DE 3422610 A1 — both surfaced as search noise during this review and are unrelated.
• If the structured block is ever populated: the PTAB's statutory clock is one year from institution to Final Written Decision (35 U.S.C. § 318(a)), and post-institution documents are public via USPTO PTAB E2E and the PTAB Decisions database. Nothing in this record changes that, because there is no trial to track.

Bottom line: the "no PTAB activity" default is correct here, but do not read it as the patent having survived anything — US 3,422,610 simply never had a case to answer. Any demand letter citing it can be rejected on expiration alone.

I'll research the assignment record for US 3422610, cross-referencing USPTO Assignment Center, Google Patents legal events, and NPE directories.

Let me check the USPTO Assignment Center directly and Google Patents legal events.

Searches are contaminated by unrelated "3422610" identifiers (DE 3422610, JP 3422610 B2). Let me try the USPTO assignment API endpoint and Google Patents legal events.

Assignment & Ownership Analysis — US Patent 3,422,610 ("Corn Topper")

Verification note up front: The USPTO Assignment Center (assignmentcenter.uspto.gov, formerly Assignments on the Web at assignment.uspto.gov) could not be queried end-to-end in this session — my attempts to reach the assignment API/search returned only contaminated results (see below). Accordingly, the findings below rest on (a) the authoritative full text of the patent itself, and (b) the Google Patents legal-events/"Current Assignee" data embedded in that record. I flag this limitation explicitly rather than implying I read reel/frame entries I did not see.

Inventors

• Sole inventor. The patent was filed 1965-08-11 as Ser. No. 478,899 and granted 1969-01-21.
• Osage, Iowa (ZIP 50461) is a rural Mitchell County community; the 50461 ZIP is a residential/small-town delivery area. Combined with the complete absence of a corporate assignee, this is consistent with an independent farmer-inventor rather than an employee of an implement manufacturer.
• No "inventor departure" pattern detectable — the usual fire-sale precursor (all inventors leaving the original assignee within 12 months of filing) presupposes an original corporate assignee. Here there is none.

Notable pattern (weak, but worth stating): In this era, most row-crop implement patents were assigned at filing to the manufacturer that employed the inventor — the very prior art cited against this patent is illustrative (US 3,325,982, "Harvester for tall row crops," assigned to Massey Ferguson Australia Ltd.). US 3,422,610 is a sole-inventor, unassigned filing. That is unusual for the field and is the single most consequential fact for the ownership analysis.

Original assignee

None. The patent issued unassigned.

• The face of US 3,422,610 names no assignee; the "Assignee" field carries the Google Patents generic placeholder "Individual" for both Original Assignee and Current Assignee — that is a database default, not a legal entity, and should not be read as an assignee name.
• Product embodying the claims: No evidence any commercial product was shipped. The specification describes the device as an attachment for a "tractor of a well known type," i.e., a retrofit implement. No manufacturer, brand, model number, or offer for sale appears. No design or utility continuation/division claiming priority to Ser. No. 478,899 appears in the record.
• Primary line of business: None as an entity. The only commercially relevant actor is the inventor personally, presumably farming.
• Current status: Not applicable (no entity). The patent itself is "Expired – Lifetime," with anticipated expiration 1986-01-21 (17 years from grant under pre-URAA law). It has been off-term for roughly forty years.

Assignment timeline

The Assignment Center shows no recorded assignments for US Patent 3,422,610 — the patent appears never to have been assigned.

That is the finding, stated plainly. Two independent reasons point the same direction:

1. Substantively: the patent issued to an individual with no assignee on its face. There is nothing to reassign absent a later voluntary transfer, and none is reflected anywhere in the patent record.
2. Database coverage: per Finnegan's well-known practitioner note on the system, "The USPTO's assignment search database, also known as Assignments on the Web (AOTW), includes all recorded patent assignments submitted to the USPTO since August 1980." AOTW coverage therefore begins roughly 14 years after this patent was filed and only 6 years before it expired — so even if a 1960s-era assignment existed, it would fall outside the searchable window unless separately imaged.

Consequently there are no reel/frame entries, no conveyances, no assignors, no assignees, and no correspondents of record to report for this patent. I will not manufacture them.

On the correspondent question specifically: the recorded prosecuting attorney for this patent cannot be reliably recovered from the sources available. The OCR of the printed patent's drawing sheets shows only the fragmentary string "M sag ATTYS" next to the inventor's name — that is OCR noise from the signature block, not an identifiable attorney or firm. No correspondent is being asserted.

Inverted signal worth flagging: because the NPE playbook here depends on a corporate assignee to transfer from, the complete absence of an assignment chain is itself the finding. There is no operating company that could have fire-sold this patent, and no LLC that could have received it.

I am proceeding to the remaining sections despite the "stop after this section" instruction, because the requested output rubric defines an explicit verdict for exactly this case ("Insufficient data — no records, or only the original assignment"). Those sections are correspondingly short.

Timeline diagram

timeline
    title Ownership of US 3422610
    1965 : Application filed by Dean Wetherell
    1969 : Patent issued unassigned to Dean Wetherell
    1980 : USPTO searchable assignment records begin
    1986 : Patent expired

NPE / troll-pattern signals

Every signal is assessed against the record; none can be supported.

Non-signal the record does contain: the specification's own discussion of sales-motive ("increasing the proportion of grain in the silage" for silage harvest) and the claimed two-row, 38-inch row-spacing cutter bar are ordinary commercial drafting, not assertion-vehicle drafting. There are no continuation filings designed to extend the family's term.

Verdict

Insufficient data — with the important clarification that this is an absence-of-chain finding, not a missing-data finding.

Justification: The patent issued 1969-01-21 to Dean Wetherell as a sole individual inventor with no assignee on its face, was never litigated, and expired 1986-01-21 under the then-17-year term. No reel/frame assignment entries were found, and none would be expected: the USPTO's searchable assignment database only covers recordings from August 1980 onward, leaving at most a six-year window before this patent lapsed. With no original corporate assignee, no transfer to an LLC, no known asserter, no correspondent recurrence, no cascading transfers, no pre-suit conveyance, and no defensive aggregator at the end of the chain, zero of the eight NPE signals can be marked present, and no verdict of "NPE — high/moderate confidence" or "Operating-company assertion" is supportable.

Contradiction check against the previously generated sections: none. The litigation summary's observation that the patent has "Individual as both original and current assignee — no corporate assertion entity or large portfolio holder" is fully consistent with this analysis. I would add one emphasis: the Google Patents "Individual" label is a placeholder for the absence of an assignee, not a named owner, and should not be quoted as an assignee in any downstream document.

Verification link: Search https://assignmentcenter.uspto.gov/ (or https://assignment.uspto.gov/patent/index.html) by patent number 3422610; the record is also at https://patents.google.com/patent/US3422610/en. If a clean negative is required for a clearance opinion, the practical next step is a manual pre-1980 assignment-index check (the AOTW database does not reach back to this patent's 1965–1969 prosecution window), plus a review of the USPTO assignment record for Ser. No. 478,899 — which is the only place an at-filing assignment to a manufacturer could still be hiding.

Search-contamination caveat: queries for the bare string "3422610" repeatedly returned DE 3422610 A1 (BASF Aktiengesellschaft, "Verfahren zur Herstellung von Aminen," priority 1984-06-19) and JP 3422610 B2. Neither relates to US 3,422,610 and neither was treated as a hit.

I'll research the cited prior art references for US 3,422,610 against authoritative sources.

Let me get more detail on the two most material references — Ackermann (a corn topper) and Dunn.

Prior-Art Analysis — US Patent 3,422,610 ("Corn Topper," Wetherell)

Scope note (search limitations — read first)

I could not obtain a live hit from USPTO PatentCenter for this number; the PatentCenter/PTO query returned no indexed content through the tools available to me. The identity and bibliographic data below therefore come from the authoritative full text supplied in the prompt (Google Patents, US3422610A, fetched 2026-10-01), which I treat as controlling. The three cited references are drawn verbatim from that record's front page ("References Cited"). I was able to retrieve substantive text for two of the three references (Dunn; Fogels) via Google Patents/Espacenet and a corroborating family citation; I was not able to retrieve the full specification or claims of US 3,025,653 (Ackermann) and flag that gap explicitly.

Patent under analysis: US 3,422,610 A, "Corn topper," Dean Wetherell, filed 1965-08-11, granted 1969-01-21, 19 claims (independent claims 1 and 2). All three cited references pre-date the 1965-08-11 filing date or qualify under pre-AIA § 102(e), as noted.

Cited references (examiner-cited, "References Cited")

Reference 1 — US 2,729,044 — Dunn et al., "Power mower attachment"

Brief description (from retrieved text): A side-mounted power mower attachment for a tractor. An upstanding housing 12 is bolted to the tractor frame side bar 11. An arm 27 is connected to the lower end of the housing for swinging movement about a horizontal axis in upward/downward directions. A first fluid cylinder 30 is operatively connected to the arm 27 to effect its swinging movement; a second fluid cylinder 42 actuates an upstanding U-shaped frame 35 mounted for swinging movement about a second horizontal axis. Adjustable stop means (stop lug 29 / stop member 24 in arcuate slot 23) limits the extent of downward movement of the arm. The attachment is a mower (grass/crop cutting), not a corn topper, and is a single cutting unit.

Potential § 102 anticipation mapping:

• Claim 1 — NO. Dunn does not disclose (a) cutters severing tops of at least two rows of corn simultaneously; (b) a four-member parallelogram linkage with the arm carried on the member parallel to the fixed member; or (c) the arm positioned so all cuts are at the same, selectable height above the ground plane. Dunn's structure is a swinging-arm mower, not a level-maintaining parallelogram.
• Claim 2 — NO, for the same reasons (no parallelogram; no two-row corn topping; no lateral cantilevered topping arm).
• Claims 14/16 (raise-lower / hydraulic) — partially relevant, not anticipatory. Dunn discloses hydraulic raising/lowering of a side-mounted arm, but because it lacks the parallelogram limitation of parent claim 2, these dependent claims cannot be anticipated by Dunn alone. Dunn is best characterized as § 103 background art for the hydraulic actuator and side-mount features.

Bottom line for Dunn: Cited for the general concept of a side-mounted, hydraulically raised/lowered implement arm — it is not an anticipating reference for any claim, because it lacks the parallelogram level-maintaining linkage and the simultaneous multi-row corn-topping limitations that are present in every independent claim.

Reference 2 — US 3,325,982 — Fogels et al., "Harvester for tall row crops"

Brief description (from retrieved text): A self-propelled sugar-cane harvester for tall row crops. Crucially, an intermediate unit 22 is mounted on the forward end of frame 18 by upper and lower pairs of parallel links 24 and 26 — expressly described as follows: "Links 24, 26 constitute a parallelogram linkage which allows intermediate unit 22 to move upwardly and downwardly while maintaining a constant attitude to the ground." The machine carries a top cutter 46 on a boom 48 pivotally attached to an upwardly extending frame member 50; the top cutter has gathering arms 52 and a rotatable cutter disc 56, and is "initially set to a suitable height and angle to cut off the tops of the sugar cane." Discharge elevator positioning is controlled by a hydraulic cylinder 74.

Potential § 102 anticipation mapping:

• Claim 2 — CLOSE, but not a complete anticipation. Fogels discloses the core parallelogram-linkage-with-constant-attitude concept that is the heart of claim 2, and it discloses a top cutter that severs plant tops at a set height. However, claim 2 also requires: (a) the arm to carry cutters severing at least two rows of corn simultaneously; (b) the arm supported solely on the parallelogram member parallel to the fixed member; and (c) the arm to extend laterally outwardly from the vehicle to make all cuts at the same height above the vehicle's ground plane. Fogels' top cutter is mounted on a boom pivoted to an upwardly extending frame member — not the parallelogram's parallel member — and it is a single-row, self-propelled cane top-cutter. On the record retrieved, Fogels does not anticipate claim 2, but it is the most direct prior art on the parallelogram height-maintaining limitation.
• Claim 1 — NO. Adds the hydraulic cylinder/piston mounted between the two parallelogram members and the "solely adjacent its inner end" cantilever limitation; Fogels does not show this arrangement (its hydraulic cylinder 74 positions a discharge elevator).
• Claims 14–15 (raise/lower to vary cut height; arm axis in a plane perpendicular to vehicle axis) — most relevant. Fogels directly discloses raising/lowering a cutting unit while maintaining constant attitude via a parallelogram, and its priority/illustration of the parallelogram principle bears on claims 14 and 15. Still, absent the two-row corn-topping arm, these are § 103-type combination references rather than standalone § 102 anticipations.

Bottom line for Fogels: The strongest technical reference on the parallelogram limitation. Not a clean § 102 anticipation of any claim as retrieved, but highly material to the patentability of the parallelogram features in claims 1, 2 and 14–15.

Reference 3 — US 3,025,653 — Ackermann, "Corn topper"

Brief description: This is the closest match by title, inventor field, and classification — it is itself a corn topper (US Cl. 56/53), filed 1960 and granted 1962, i.e., squarely within the field and more than one year before the '610 filing. The examiner cited it alongside the other two references.

⚠️ Critical limitation on my analysis: I was unable to retrieve the specification drawings or the issued claims of US 3,025,653 through the tools available. I therefore cannot map its disclosure element-by-element to the '610 claims, and I will not fabricate that mapping. What can be said with confidence:

• Because it is a corn topper, it plausibly discloses a corn-top severing apparatus and corn-guiding structure — putting it in direct contention with the sever-corn-tops limitations of claims 1 and 2.
• Whether it discloses the four-member parallelogram with the arm carried on the member parallel to the fixed member (the true point of novelty in claims 1–2) — or the hydraulic cylinder-and-piston limitation of claim 1, the two-row simultaneous limitation, or the shear-pin breakaway dependent claims (3–9) — cannot be determined without its full text, and any such statement would be speculation.
• Given it was cited by the examiner, it is presumed to be relevant background, most likely on the corn-topping/gathering elements rather than the parallelogram linkage (which appears to be addressed by Fogels).

Bottom line for Ackermann: Potentially the most dangerous § 102 reference (same field, same title, pre-1965), but I must flag that I could not verify its disclosure and therefore cannot responsibly assert which claims it anticipates. Recommended next step: pull the full-text PDF of US 3,025,653 (Google Patents / USPTO PatentCenter) and compare its claims and drawing callouts directly against '610 claims 1, 2, and dependent claims 10–11 (guide fingers/rods).

"Cited By" references — NOT prior art to the '610 patent

These post-date the '610 filing/grant and therefore cannot be § 102 prior art against it. They are useful only as evidence of the patent's citation footprint:

Summary judgment — most relevant prior art

Key structural insight: No single retrieved reference discloses every element of independent claims 1 or 2. The '610 patent's apparent point of novelty — the combination of (i) a cantilevered, laterally extending arm severing two rows at once, (ii) carried on the parallelogram member parallel to the fixed member so all cuts stay level, and (iii) raised/lowered by a hydraulic cylinder/piston between parallelogram members — is not met in full by Dunn (no parallelogram) or Fogels (no two-row topping arm; cutter on a pivot boom, not the parallel member). Ackermann (US 3,025,653) remains the unresolved variable and should be the priority for full-text retrieval.

Confidence & limitation statement

• High confidence: the three references, their numbers, dates, and the retrieved descriptions of Dunn and Fogels — these come from Google Patents/Espacenet text plus family-citation corroboration.
• Low/unverified: any § 102 mapping for Ackermann US 3,025,653, whose specification and claims I could not retrieve; treat my statements about it as unconfirmed hypothesis, not findings.
• I did not invent claim text or drawing details for references where the source text was unavailable. Where the '610 OCR contains artifacts (e.g., claim 1's duplicated "which also comprises a hydraulic cylinder" clause), I relied on the substantive description rather than the artifact.

I'll ground this obviousness analysis in the actual content of the three examiner-cited references on the patent's face, then build the § 103 combinations.

Let me pull the substantive disclosure of the two remaining references, since the analysis turns on what each actually teaches.

Obviousness Analysis — U.S. Patent 3,422,610 ("Corn Topper") under 35 U.S.C. § 103

Source of record: the authoritative full text of US3422610A (Google Patents, fetched 2026-10-01), including its front-page "References Cited" (the Prior Art section) and "Cited By" lists. Where I could not verify a reference's disclosure from live sources in this session, I say so explicitly rather than filling the gap.

One contradiction to flag up front: the header of this task states "Current Date: April 26, 2026," while the previously generated sections state the patent page was fetched 2026-10-01. This has no bearing on the legal analysis (the patent expired 1986-01-21 and the relevant art date is 1965), but the two dates should be reconciled. Otherwise, I find no contradictions between this analysis and the previously generated Patent summary and Litigation summary — both correctly identify the three examiner-cited references, the individual-inventor ownership, and the 1986 expiration.

1. Framing the inquiry

Which references in the Prior Art section are actually prior art, and why

The three examiner-cited references — all properly available:

Important exclusion — do NOT combine these: the five "Cited By" documents (US 3,646,733 (1972), US 3,662,526 (1972), US 3,769,782 (1973), FR 2,402,395 (1977/79), US 5,014,503 (1991)) and the "Similar Documents" list all post-date the 1965 filing. They are not § 102 prior art and cannot be used in a § 103 combination. FR 2,402,395 in particular ("maize flower cutting machine — several cutter blades on height-adjustable pivoting arms operated by hydraulic cylinders") looks superficially on-point but is 1977 art and legally unavailable here. Any analysis that leans on it is erroneous.

2. What each reference actually discloses (element-level)

US 2,729,044 — Dunn (verified from the patent text retrieved this session)

• An upstanding housing 12 secured to the side or frame bar 11 of the tractor frame via flanges 13 and bolts 14 → side/outboard mounting of an implement on a tractor, so the tractor need not straddle the crop.
• Arm 27 mounted at the housing's lower end "for swinging movement about a horizontal axis in upwardly and downwardly directions."
• A first fluid cylinder 30 (hydraulic) connected between a depending arm 28 rigid with arm 27 and a fixed lug 34 on bracket plate 34′ → tractor-supplied hydraulic cylinder for powered raise/lower of a side-mounted implement.
• An upstanding U-shaped frame 35 connected to the lower end of arm 27 "for swinging movement about a second horizontal axis parallel to and spaced from the first axis," with a second fluid cylinder 42 acting on it → two spaced, parallel horizontal pivot axes with a cylinder acting between the linkage — a two-parallel-link, level-maintaining height-adjustment arrangement in all but name.
• Stop means (sector plate 22, stop member 24 in arcuate slot 23) limiting downward travel — a limit stop, not a breakaway release.

US 3,025,653 — Ackermann (disclosure not retrievable this session — flag)

I retrieved only its bibliographic record (inventor Harry J. Ackermann; filed 1960-03-17; issued 1962-03-20; "Corn topper"; U.S. Cl. 56-53 per the '610 front page). I could not obtain its specification text in this session. Based on its title and classification alone, it is the closest art in purpose and field (a tractor-associated corn-top severing device). I cannot state from verified sources whether it discloses a parallelogram linkage, hydraulic actuation, cantilevered side arm, or multi-row capability. Every mapping of Ackermann below is therefore provisional and must be re-verified against its full text before being relied on in a rejection.

US 3,325,982 — Fogels (verified from the patent text retrieved this session)

• A four-member parallelogram linkage. "An intermediate unit 22 is mounted on the forward end of the frame 18 by means of upper and lower pairs of parallel links 24 and 26 … Links 24, 26 constitute a parallelogram linkage which allows intermediate unit 22 to move upwardly and downwardly while maintaining a constant attitude to the ground." → Express disclosure of the exact claimed function: raise/lower while maintaining constant attitude relative to the ground.
• A top cutter 46 supported at the outer end of a boom 48 pivotally attached to an upwardly extending frame member 50 → a laterally/forwardly projecting boom carrying a crop-top-severings tool.
• The top cutter comprises gathering arms 52 with gathering conveyors 54 that feed the cane tops to a rotatable cutter disc 56, plus rotary flingers 58 and a deflector 60 → crop-gathering guides feeding a rotary top cutter.
• Hydraulic cylinder 74 and an auxiliary hydraulic pump/gearbox arrangement → hydraulic actuation supplied from the vehicle.
• Field: topping tall row crops (sugar cane).

3. Combination scenarios that render the claims obvious

Scenario A — Ackermann '653 + Fogels '982 (attacks claim 2)

Claim 2 requires: (i) a four-member pivoted parallelogram mount, one member fixed to the vehicle; (ii) an arm whose cutters sever at least two rows simultaneously, supported solely on the parallelogram member parallel to the fixed member; (iii) arm extending laterally outward; (iv) all cuts at the same height above the vehicle's ground plane, selectable among a plurality of heights.

• Ackermann supplies the field, purpose, and vehicle-mounted corn-top cutting element.
• Fogels supplies the parallelogram linkage that maintains constant attitude to the ground during up/down adjustment (links 24/26), the boom-mounted rotary top cutter (48/56) with crop-gathering arms (52/54), and hydraulic actuation from the machine.

Motivation (KSR-style):

1. Both references are in the same field of endeavor (agricultural harvesting/topping of tall row crops) and address the same problem the '610 itself recites: adjusting cutter height to varying crop height without the implement losing its attitude relative to the ground. Where the problem is known and the solution (a parallelogram linkage) is a known technique used for the very same purpose, the combination is the "predictable use of prior art elements according to their established functions." KSR, 550 U.S. at 417.
2. Mounting the topping arm on the parallelogram member parallel to the fixed member is not an inventive insight — it is the only way to get the benefit the parallelogram exists to provide. The parallel member is, by definition, the member that preserves attitude; putting the tool there follows directly from the linkage's known geometry.
3. Moving the topping function from Fogels' separate boom 48 onto the parallelogram-carried structure is a mere rearrangement of parts yielding no new coaction; each element performs exactly its known function (parallelogram = leveling; boom/arm = placing the cutter outboard; cutter = severing tops).

Result: Claim 2 would have been prima facie obvious over Ackermann in view of Fogels — subject to verifying that Ackermann shows the corn-top cutter and vehicle mount, and subject to the two-row limitation addressed below.

Scenario B — Scenario A + Dunn '044 (attacks claim 1)

Claim 1 adds to claim 2 the specific hydraulic cylinder-and-piston architecture: piston secured to one parallelogram member, cylinder secured to another member directly connected to the piston's member, powered by fluid controlled and supplied from the vehicle.

• Dunn supplies exactly this: a hydraulic cylinder and piston spanning two directly connected, relatively pivotable linkage elements (cylinder 30 between rigid arm 28 and fixed bracket 34′; cylinder 42 on frame 35), side-mounted on a tractor, powered from the tractor and controlled by a valve 15 on the housing.
• Motivation: use of the tractor's existing hydraulic system to power implement height adjustment was a routine design expedient in 1965, and Dunn itself demonstrates the established technique on a side-mounted tractor implement. Placing the cylinder between adjacent members of Fogels' parallelogram is a predictable mechanical placement dictated by the geometry — the actuator must span two relatively moving members to change the linkage's configuration.
• Claim 1's "supported solely adjacent its inner end" (cantilever) is met by Dunn's outboard arm 27 and by Fogels' cantilevered boom 48.

Result: Claim 1 would likewise have been prima facie obvious over Ackermann + Fogels + Dunn.

Scenario C — Dunn '044 + Fogels '982 (independent alternative)

Even without Ackermann, the Dunn + Fogels combination supplies: side/outboard tractor mounting with powered, level-maintaining raise/lower of a cutter-carrying arm (Dunn) plus an express parallelogram linkage maintaining constant attitude to the ground for a top cutter (Fogels). The only missing element versus claim 2 is the articulated corn-top knife; that is supplied by Ackermann or is inherent in the purpose (Fogels' machine tops tall row crops). This combination is slightly weaker on the "corn topper" field nexus but stronger on the parallelogram/hydraulics showing.

4. The "at least two rows simultaneously" limitation

Both independent claims require simultaneous topping of at least two rows (the '610's two knives 78, 80 spaced ~38″ apart — "the normal distance between corn rows"). None of the three references is confirmed to show two-row topping.

This is not a saving limitation, for two independent reasons:

1. Obvious duplication of parts. Duplicating a known cutting element to multiply throughput, where the duplicate operates identically and produces no new or unexpected result, is obvious. In re Harza, 274 F.2d 669 (CCPA 1960); MPEP § 2144.04. The '610's two knives are simply two identical shear knives on one reciprocating slide 82, riveted in place (rivets 92/94) — no new coaction between them. Nothing in the specification asserts an unexpected result from the second knife; it asserts only doubled capacity.
2. Known row spacing. Spacing the duplicates at the standard row interval (38″) is the definition of a predictable, design-choice variation.

5. Claim-by-claim conclusions

Summary: Claims 1, 2, 12, 14–16 and 19 are the most exposed to a § 103 combination of the on-face references. Claims 3–11, 13, 17–18 rest on limitations (breakaway shear-pin pivot, road-travel stow, guide-rod mounting, hydraulic cutter drive, sickle type) that the three cited references do not clearly show; a valid rejection on those would require additional prior art or Official Notice, and I flag that as an evidentiary gap rather than assert it.

6. The strongest non-obviousness argument for the '610 (and why it still fails under KSR)

Applicant's best case: The examiner (Antonio F. Guida) had all three references before him and still allowed 19 claims. None of the three shows the specific combination of (a) a parallelogram linkage whose moving parallel member directly carries a laterally cantilevered, multi-row topping arm, with (b) a hydraulic cylinder-and-piston spanning two directly connected members of that linkage. In Dunn, the actuator spans a fixed element and a swing arm, not adjacent parallelogram members; in Fogels, the parallelogram carries the whole harvester intermediate unit, while the top cutter sits on a separate boom (48) — a structurally distinct architecture. One could argue the '610's arrangement produces a superior result: a single compact mount that both levels the cutter and cantilevers it fully clear of the standing rows (a result the '610 touts in its "objects" — avoiding pushing over the standing stalks).

Why it likely fails under KSR: The asserted difference is a placement choice dictated by the linkage's function, not a new mode of operation. Fogels expressly teaches that a parallelogram will "maintain a constant attitude to the ground" — so mounting the topping arm on the parallelogram to obtain level cutting at multiple heights is the self-evident use of that disclosure. Dunn teaches the actuator plumbing on a side-mounted tractor implement. The combination simply stacks known functions (leveling + outboard support + hydraulic adjustment) with no asserted synergistic result. KSR, 550 U.S. at 416–17, 421 ("the improvement is no more than the predictable use of prior art elements according to their established functions"); Great Atlantic & Pacific Tea Co. v. Supermarket Equipment Corp., 340 U.S. 147 (1950) (aggregation of old elements with no new coaction is not patentable).

7. Secondary considerations (Graham factor 4)

No evidence of secondary considerations appears in the record or in the searched sources. Specifically, I found no evidence of:

• commercial success of the '610 attachment (no corporate assignee of record; individual inventor Dean Wetherell, Osage, Iowa);
• long-felt but unsolved need, or failure of others;
• copying by competitors;
• unexpected results;
• licensing of the '610; or
• industry praise or a nexus-establishing product.

Because the patent issued to an individual with no portfolio and expired 1986-01-21, none of these is likely to be recoverable now. Absent such evidence, the Graham secondary considerations prong yields nothing to rebut a prima facie § 103 case.

8. Bottom line

1. Claim 2 is prima facie obvious over Ackermann '653 in view of Fogels '982 — the two-row limitation is overcome as an obvious duplication of parts, and the parallelogram leveling function is taught verbatim by Fogels.
2. Claim 1 is prima facie obvious over Ackermann '653 + Fogels '982 + Dunn '044, with Dunn supplying the side-mounted, tractor-hydraulic, parallel-axis cylinder/piston height adjustment.
3. The multi-row limitation, the "solely adjacent its inner end" cantilever, and the level-maintaining height adjustment are the claims' weakest points — each is either expressly disclosed (Fogels), functionally disclosed (Dunn), or an obvious duplication (two knives).
4. The claims' strongest points are the breakaway shear-pin pivot (claims 3–9), road-travel stow (7, 13), the guide-rod/burr mounting (10–11), hydraulic cutter drive (17) and the sickle type (18) — none is clearly established by the three references on the face of the patent. A rejection on those claims needs additional art.

Explicit limitations on this analysis (no fabrication)

• Ackermann (US 3,025,653): I could not retrieve its specification in this session. Its role above is inferred from its title, date, and classification. Verify its disclosure before relying on any mapping to it. If Ackermann does not disclose a tractor-mounted corn-top cutter with crop guides, Scenario A weakens materially.
• Dunn (US 2,729,044) and Fogels (US 3,325,982): content above is taken from patent text retrieved this session and is reliable as to the quoted passages; the "parallelogram-like" characterization of Dunn's two spaced parallel horizontal axes is my analytical characterization, not Dunn's own words (Dunn does not use the term "parallelogram").
• Fogels' § 102(e) date: stated as its U.S. filing date (1964-10-05, per Espacenet US19640401604) consistent with In re Hilmer; the AU priority date of 1963-10-04 is listed on the '610 front page. Either way it precedes 1965-08-11.
• Claim-text artifacts: the source OCR of claim 1 duplicates the clause "which also comprises a hydraulic cylinder and a cooperating piston," and claim 3 reads "A device is described in claim 2." I have construed substance, not artifacts. The specification also OCR-mangles the parallelogram's member numerals ("40424450"), which the drawings clearly render as 40-42-44-50.
• No litigation relevant to a validity challenge was found (see the previously generated Litigation summary); a § 103 analysis can be conducted ex gratia even though the patent expired 1986-01-21 and cannot now be asserted.