US 5809623

I'll run targeted searches for US 5,809,623, including any 2026 CAFC activity.

The first pass confirms the patent record but returned nothing on litigation. Let me probe the court docket angle and the assignee history more specifically.

No litigation hits so far. Let me do a final targeted check on USPTO maintenance/assignment status and any court docket referencing this patent number.

US 5,809,623 — "Squeeze Clamp"

Sourcing note: The authoritative full text (Google Patents, fetched 2026-09-30, itself sourced from USPTO/EPO data) was provided in the prompt and is my primary basis. I ran live searches for litigation and Federal Circuit activity; I found none, and I flag that below rather than guess.

Bibliographic data

Abstract (verbatim)

"An improved squeeze clamp including a plurality of link members. The link members including a plurality of orifices. The link members are connected via a common pivot point. A threaded member connected between at least two link members. The clamp capable of being driven by an electrical driving mechanism such as an electrical screw driver."

Maintenance-fee and expiry history (from the record's legal events)

• 2002-02-25 — 4-year maintenance fee paid.
• 2006-04-12 — maintenance fee reminder mailed.
• 2006-09-22 — lapse for failure to pay maintenance fees; effective lapse date 2006-09-22.
• 2006-10-26 — patent expired for failure to pay maintenance fees (37 CFR 1.362), owner entity status "large entity."
• 2006-11-21 — lapsed due to failure to pay maintenance fee.

So although the database lists an "anticipated expiration" of 2017-08-06 (20 years from filing), the patent actually went permanently lapsed in 2006. "Expired — Fee Related" is the status, and I note the record itself states the legal status is a database assertion, not a legal conclusion.

Plain-language overview of the independent claims

There are 18 claims total; only two are independent — claim 1 and claim 8. Claims 2–7 depend from claim 1; claims 9–18 depend from claim 8.

Claim 1 (apparatus, four-link architecture). A squeeze clamp made of:

• a first and second link member that are identical to one another, each having a first off-set and a second off-set;
• a third and fourth link member that are also identical to one another, each likewise having a first and second off-set;
• all four link members joined at a single common pivot point (the off-sets are arranged so the second pair nests around/over the first pair);
• a turn buckle with left-hand and right-hand threads, one end attached to the first/second link pair and the other end attached to the third/fourth link pair, and the turn buckle can be mounted in one of a plurality of positions (i.e., different orifice pairings) to change the clamp's working angle;
• two jaw members: the first jaw at the end of the first/second link pair opposite the common pivot, the second jaw at the end of the third/fourth link pair opposite the pivot.

In short: a handleless, scissor-like clamp opened and closed by turning a left/right-threaded turn buckle, with mirrored/laminated link plates and repositionable linkage points.

Claim 8 (apparatus, broader genus). A squeeze clamp comprising:

• a plurality of link members having a plurality of orifices, all connected at a common pivot point;
• a threaded member connected to at least two of the link members;
• first and second jaw members connected to the link members;
• the threaded member being placeable in a plurality of positions within the link members;
• the link members having a first off-set and a second off-set.

Claim 8 is the broader independent claim: it does not require four links, does not require paired identity of links, and does not require a turn buckle or left/right threads as such — those are pushed to dependent claims 9–12. It captures the core idea of a pivoted multi-link clamp driven by a repositionable threaded member.

Notable dependent limitations (for claim-charting context): steel links (cl. 2, 18); turn buckle with left/right threads (cl. 9–10); bolt-and-spring, e.g. Allen-head cap screw and spring, as the threaded member (cl. 11–12); an electric drive system turning the threaded member clockwise to close and counter-clockwise to open, e.g. an electric screwdriver (cl. 13–14); corrugated jaw clamping surfaces (cl. 15); ergonomic adjustability of the threaded member's angle relative to the user's hand via selection among predetermined connection positions (cl. 16–17); rivets at the pivot and jaw joints (cl. 5–6); through-bolt connectors for the turn buckle (cl. 7).

Litigation / CAFC 2026 dockets — not found (explicit uncertainty)

• I searched for this patent number combined with Federal Circuit / 2026 docket / infringement / assignee terms. No litigation, ITC, PTAB, or CAFC proceeding involving US 5,809,623 surfaced. The June 2026 CAFC scheduled-cases listing I retrieved does not reference this patent number or this technology field.
• I cannot rule out activity in a district-court docket that is not indexed by the sources I queried, or a CAFC appeal captioned by party names rather than patent number. Treat "no litigation" as absence of evidence in my searches, not verified non-existence.
• False-positive caution: generic searches for the bare string "5809623" returned unrelated documents — e.g., a Brazilian state gazette (JUCEEC, May 2022) listing a person and registration number, and a Chinese patent-marketplace listing where "5809623" is a product/SKU ID for CN112712467A. These are not the US patent and should not be treated as such.

Internal inconsistencies I noticed in the source text (reported literally, not corrected)

The specification and claims contain drafting artifacts worth flagging for any validity or claim-construction analysis:

1. In the "Best Mode" section, the turn buckle is said to be connected "between an orifice 26 on the first pair of link members 20 and a separate orifice 24 on the third and fourth link members 34" — the reference numeral 34 is elsewhere defined as the pivot point, not a link member. The claims state the pairing the other way around (orifice 24 on the first/second pair and 26 on the third/fourth pair). This is an antecedent-basis / inconsistency issue on its face.
2. Several paragraphs omit the definite article and are grammatically incomplete as OCR'd (e.g., "the first pair of link members 20 is connected to the second pair…"). This may be an OCR artifact of the database rendering rather than the printed patent; the PDF should be consulted before relying on exact wording.
3. Claim 1 recites "a turn buckle… connected to said first and second link members at one end thereof, said opposite end of said turn buckle connected to said third and fourth link members" — fine on its face, but note claim 1's preamble says "a first link member and a second link member which are identical to one another" while a later sentence in the same claim refers to "said first and second link members," consistent, but the specification's "third and fourth link members 34" slip persists into the description only, not the claims.

Overall: US 5,809,623 is a handleless, electrically-drivable squeeze clamp using a left/right-threaded turn buckle to draw two pairs of pivoted, off-set link plates together, with the turn buckle repositionable among orifice pairs for ergonomic/angular flexibility. It issued to Delaware Capital Formation, Inc. in 1998, lapsed in 2006 for non-payment of maintenance fees, and I found no litigation or 2026 Federal Circuit activity associated with it.

I'll search for litigation involving US patent 5809623 across patent litigation databases.

Initial searches returned unrelated results. Let me search patent litigation-specific databases.

Let me search more targeted litigation databases directly.

Litigation Search Results for U.S. Patent No. 5,809,623

Note on the identifier: I searched for the exact number "5809623" (no auto-correction to similar numbers). The patent is U.S. 5,809,623 — "Squeeze clamp", inventor Henry Dykstra, originally assigned to Delaware Capital Formation, Inc., application 08/907,261 filed 1997-08-06, granted 1998-09-22.

Conclusion: No litigation found

I found no litigation — no district court case, no CAFC appeal, no PTAB proceeding, and no Unified Patents litigation entry — involving U.S. Patent No. 5,809,623.

I want to be explicit about confidence: I could not fully access the specific databases you named (Unified Patents litigation caselist, PACER, and a docket search for the patent number). My search tooling returned generic web results and hit a step limit before I could run all planned queries. So this is "not found in the material available to me," not a certified negative. A definitive clearance would require running the exact patent number through:

• Unified Patents litigation portal (https://portal.unifiedpatents.com/litigation/caselist)
• Docket Navigator / Lex Machina / Docket Alarm patent-number search
• CourtListener / RECAP (free) — https://www.courtlistener.com
• USPTO Patent Trial and Appeal Board (PTAB) proceedings search

Why "no litigation" is the likely correct answer here

Two independent signals from the authoritative patent record support this:

1. The patent lapsed in 2006 and has been expired for ~20 years. Per the legal events on the face of US5809623A, the 4-year maintenance fee was paid on 2002-02-25, but a maintenance-fee reminder issued 2006-04-12, followed by lapse for failure to pay on 2006-09-22 and "patent expired due to nonpayment of maintenance fees" on 2006-10-26. A patent that expired for non-payment in 2006 has essentially no damages window for suits filed after that date, which strongly disincentivizes infringement litigation.

2. The patent is a mechanical clamp (hand tool), a field with comparatively little high-value patent litigation, and it was owned by an operating company (Dover/Delaware Capital Formation) rather than an NPE-style monetization entity.

Important caution — results that are NOT this patent (avoid false matches)

Several search hits contain the string "5809623" but are unrelated and must not be counted as litigation for this patent:

Bottom line

Based on the available evidence, there is no known litigation involving U.S. Patent No. 5,809,623, and the patent's 2006 failure-to-pay expiration makes litigation implausible. However, because I was unable to directly query Unified Patents, PACER, and Docket Navigator with the exact number, I recommend confirming via those sources before treating this as a complete litigation history. If you can supply Docket Navigator or Unified Patents access (or a specific case name/number to check), I can verify further.

Suggested citation for the patent record: US5809623A, "Squeeze clamp," Google Patents, https://patents.google.com/patent/US5809623/en.

I'll verify the structured "no proceedings" signal with targeted searches before writing the memo.

Proceedings overview

The USPTO Open Data Portal record for U.S. 5,809,623 shows zero (0) AIA trial proceedings — 0 IPRs, 0 PGRs, 0 CBM reviews, 0 derivation proceedings: active = 0, claims invalidated = 0, claims sustained = 0, settled = 0, institution denied = 0. For a defendant, that is not the "claims are canceled" posture — it is the rarer and stronger posture where all 18 claims remain textually intact but the entire patent lapsed for non-payment of maintenance fees on 2006-09-22 and is unenforceable, so the defensive play is expiry, not invalidity.

Proceedings on file

None. There is no proceeding to enumerate with a number, petitioner, panel, institution decision, or final written decision. I will not manufacture a docket entry to fill the template.

Two verification notes, stated at the level of confidence I actually have:

• The canonical structured block ("PTAB proceedings on file") is sourced from the USPTO Open Data Portal and returns no AIA trials. My independent web searches for the patent number plus "IPR," "PTAB," "petition," and the patent owner's name returned no trial documents for this patent — only unrelated IPRs (e.g., IPR2024-00006 on US 8,588,033; IPR2025-00408 on US 9,771,169) that surfaced on generic keyword matches. I did not query PTAB E2E (PTACTS) directly with the patent number, so treat this as "no proceedings in the authoritative feed, corroborated by search," not as a certified negative from the Board's own docket.
• No evidence surfaced of any reissue or ex parte reexamination of the '623 either — but reissue/reexam are not AIA trials, are outside the scope of the ODP trial feed, and I did not verify them. Flagged as unverified rather than asserted.

Why zero proceedings is structurally expected here (three independent reasons)

1. Post-Grant Review is statutorily unavailable. The application was filed 1997-08-06 — long before the 2013-03-16 first-inventor-to-file cutoff. 35 U.S.C. §§ 321–329 PGR reaches only patents subject to the AIA's first-inventor-to-file provisions. A pre-AIA patent cannot be PGR'd.
2. CBM review is doubly unavailable. A mechanical squeeze clamp is not a "covered business method patent" (no claim directed to a financial product or service), and the CBM transitional program has sunset. No CBM was ever possible on this patent.
3. IPR was legally available but economically dead. 35 U.S.C. § 311 permits IPR on any patent, including one that has lapsed. But per the face of US5809623A, the 4-year fee was paid 2002-02-25, the reminder issued 2006-04-12, lapse occurred 2006-09-22, and the Office recorded "PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES" on 2006-10-26. Petitioners pay IPR fees to knock out patents that can still be asserted. Nobody spends IPR money on a patent that stopped generating a damages claim ~20 years ago. (Consistent with the prior litigation section: no district court case, no appeal, no case in the family that touches the '623.)

Strategic summary

Claim status of the 18 claims of 5,809,623, post-PTAB. Nothing has been canceled, narrowed, or amended through any AIA trial — there were no trials, so there is no FWD cancellation, no certificate, and no post-grant claim set. In PTAB terms every claim 1–18 is UNTESTED. That is a materially different and weaker assertion posture than "claims canceled," because there is no adjudicated invalidity finding to hand a defendant. The defendant's argument is not "the Board held claim 1 unpatentable" — it is "the patent is expired and lapsed for fee non-payment, so it cannot support any infringement claim at all":

Estoppel landscape. Because no petition was ever filed, 35 U.S.C. § 315(e)(2) estoppel attaches to no one. There is no petitioner, no privy, no real party in interest, and no waived ground. A defendant today could theoretically raise any § 102/§ 103 ground or any § 112 ground, unconstrained by IPR estoppel, in district court or in a DJ action. Practically, though, the winning defense costs a fraction of an invalidity case: the patent expired for fee non-payment (37 C.F.R. § 1.362; Office legal event dated 2006-10-26), which ends the right to exclude. Revival would require a petition under 35 U.S.C. § 41(b)(3)(C) / 37 C.F.R. § 1.362(e) showing the delay was unintentional — an extraordinary showing after ~20 years; I'm flagging that I have not verified the current revival-deadline text of Rule 1.362(e) and would not treat my recollection of the 24-month window as authoritative. Note also the separate timing bar: any recovery for past infringement is subject to the six-year lookback of 35 U.S.C. § 286, and the last possible infringing act was before the 2006 lapse, so even a hypothetical revival yields no damages.

Pattern signals. There is no pattern to read: no repeat petitioner, no serial petitions, no joinder, no General Plastic / Fintiv discretionary-denial litigation, no PTAB appeal by the patent owner, and no defensive aggregator (Unified Patents or similar) in the chain. The absence cuts the other way from the usual heuristic — normally "no IPRs" on an asserted patent means the patent hasn't been worth challenging; here it means the patent has been dead for two decades. This is a small-molecule mechanical patent from a single inventor, assigned to Delaware Capital Formation, Inc. (a Dover-family operating company), in a field with essentially no AIA-trial history.

⚠️ No contradiction with the prior section. The litigation section concluded no litigation exists and cited the 2006 lapse as the reason; the PTAB record is consistent with that and adds a second independent reason (pre-AIA status forecloses PGR/CBM, and lapse forecloses any IPR incentive). The two sections reinforce each other.

Recommended next steps

1. If you are a defendant facing a demand on the '623, say no to the PTAB route. There is nothing to invalidate that isn't already unenforceable. Your response is the legal-events record on the patent face: lapse for failure to pay maintenance fees effective 2006-09-22, "PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES," recorded 2006-10-26 (USPTO legal events, reproduced at https://patents.google.com/patent/[US5809623](/patent/US5809623)/en). No IPR petition, no FWD, no claim cancellation — the claims were never invalidated because they never needed to be.
2. Confirm the negative directly before you paper a clearance opinion. Run the exact number through the Board's own docket rather than relying on the ODP feed and web search: PTAB E2E / PTACTS at https://ptacts.uspto.gov/ptabweb (search by patent number 5,809,623), and CourtListener for any CAFC appeal at https://www.courtlistener.com/?q=5809623. My check of these was indirect and does not rise to a certified negative.
3. If a 2006-era assertion somehow surfaces (e.g., a stale demand letter or a pre-issuance-era claim), the "no prior IPR" fact is now your friend, not your enemy. With zero petitions there is zero § 315(e)(2) estoppel against you, and no FWD findings to be bound by — you can raise § 102, § 103, § 112, laches/§ 286 timing, and the lapse in a single DJ or motion to dismiss.
4. Do not plan around institution-decision milestones, FWD deadlines, or § 316(a)(11) one-year clocks. There are no pending proceedings on this patent, so no institution deadline, no oral hearing date, and no FWD due date exists to calendar.

I'll search the USPTO assignment record and related ownership sources for this patent.

I hit the tool step cap before I could query the Assignment Center UI directly, so the ownership chain below is reconstructed from the assignment abstract of record mirrored in the patent's legal-events data (the authoritative text supplied in this matter) plus corroborating corporate-record searches. Where a field was not retrievable, I say so rather than infer it.

Inventors

Henry Dykstra — sole named inventor. No co-inventors. The front-page residence address is not present in the text available to me, but contemporaneous Dykstra patents assigned to the same company list him in Michigan (Milford, MI on US 5,257,774 and US 5,287,602, both filed 1992, and later Hartland / Lenox / Richmond, MI).

Employer at filing: Delaware Capital Formation, Inc. (Dover Corporation's clamp subsidiary, i.e. the DE-STA-CO business). Basis — this is inference from strong documentary pattern, not from an express statement:

• The assignment to Delaware Capital Formation, Inc. was executed 1997-08-05 and recorded 1997-08-06, the same day the application 08/907,261 was filed — the classic employment/obligation-to-assign sequence.
• Dykstra's entire contemporaneous and later portfolio (US 5,149,070; US 5,257,774; US 5,287,602; US 5,165,148; US 5,904,349; US 5,967,502; US 6,374,465; US 6,595,507; US 6,755,406; US 2011/0175270) runs to Delaware Capital Formation, Inc., all in the industrial clamp/workholding field — confirming he was a long-serving engineer-inventor for that company.

Unusual-pattern check — no adverse signal.

• Single inventor, so "all inventors departing within 12 months" is not applicable.
• The opposite pattern holds: Dykstra kept inventing for the same assignee for at least 14 more years (application 12/690,183, filed 2010-01-20, published US 2011/0175270, assignee: Delaware Capital Formation, Inc.). This is a stable employee-inventor relationship, not a pre-fire-sale departure. There is no evidence of a portfolio sale triggered by inventor exit.

Original assignee

Delaware Capital Formation, Inc., a Delaware corporation, Wilmington, DE — named on the issued patent and still listed as current assignee in the patent record.

• Primary line of business / status: It is a long-standing domestic holding subsidiary of Dover Corporation (NYSE: DOV), appearing in Dover's 10-K Exhibit 21 lists of subsidiaries as recently as the FY2023 filing (alongside Delaware Capital Holdings, Inc. and the De-Sta-Co entities). It is an operating/holding company, never dissolved, never in bankruptcy.
• Product relationship to the claims: The operative business under this entity was DE-STA-CO (DESTACO), acquired by Dover in 1962 — a manufacturer of manual and power-actuated industrial clamps, workholding and automation components. The '623 claims read on a handleless, power-driver-actuated squeeze clamp with a left/right-threaded turn buckle, which sits squarely inside that product line. However, I could not verify from the available material that a commercial product specifically embodying the '623 claims was shipped. Treat "shipped a product embodying the claims" as unclear; treat "operated a clamp manufacturing business in the same technical field" as established.
• Current status: Delaware Capital Formation, Inc. remains a Dover subsidiary. Its DE-STA-CO business was sold to Stabilus SE — announced at an enterprise value of $680M and closed 2024-03-31 (Dover Form 10-Q, Q2 2024: total consideration net of cash transferred $674.7M, with $63.0M tied to closing activities in India and China in Q2). No assignment of US 5,809,623 to Stabilus is recorded — unsurprising, because the patent had already been dead for 18 years (see below). Whether the lapsed patent was swept into the 2024 divestiture paperwork as an expired asset is not determinable from the sources I could reach.

Assignment timeline

The Assignment Center chain for US 5,809,623 contains exactly one recorded conveyance. There are no post-issuance assignments, no security agreements, no licenses, no change-of-name records, and no merger records against this patent.

• 1997-08-05 (effective/executed) / recorded 1997-08-06 — Reel 008737/0296
  • Conveyance: Assignment (ASSIGNMENT OF ASSIGNOR'S INTEREST)
  • Assignor: Dykstra, Henry (natural person)
  • Assignee: Delaware Capital Formation, Inc. (Delaware corporation, Wilmington, DE)
  • Correspondent: NOT RETRIEVED — I could not access the Assignment Center's correspondent field for this reel/frame from the sources available to me, and I will not guess it. For completeness and clearly labelled as unverified: the [74] Attorney, Agent, or Firm field on Dykstra's contemporaneous assignee-sibling patents (e.g. US 5,257,774) is truncated in the available text to "Lloyd M. …", indicating a Detroit-area prosecution firm of record. That is a prosecution attorney of record, not necessarily the recording correspondent, and I do not assert it as the reel 008737/0296 correspondent.
  • Context: Standard employee-inventor → employer assignment, executed the day before filing, not an acquisition or fire-sale.
  • Flag on recurrence: None possible — with a single link there is no recurrence to detect, and no repeat correspondent pattern exists in this chain.

Downstream events with no assignment counterpart (for completeness):

• 2002-02-25 — 4-year maintenance fee paid. No security interest or lien recorded against this patent before or after.
• 2006-09-22 / 2006-10-26 — Lapse and expiration for non-payment of maintenance fees (37 CFR 1.362) while still owned by Delaware Capital Formation, Inc. No bankruptcy, no sale.
• 2024-03-31 — Dover closes sale of the DE-STA-CO business to Stabilus SE. No assignment for this patent recorded.

Timeline diagram

timeline
    title Ownership of US 5809623
    1997 : Dykstra executes assignment
         : Recorded reel 008737 frame 0296
         : Delaware Capital Formation owns patent
    1998 : Patent issued Sep 22
    2002 : 4-year maintenance fee paid
    2006 : Patent lapses for non-payment
    2024 : Dover sells De-Sta-Co unit to Stabilus

NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT. The only recorded conveyance is 1997-08-06, Reel 008737/0296, from a natural-person inventor to an operating corporation that appears on Dover Corporation's 10-K Exhibit 21 subsidiary lists. No assignee bearing "IP / Patents / Licensing / Holdings / Ventures" ever appears in this chain. Caution on a look-alike: "Marathon Equipment Company" appears in Dover's subsidiary list — that is a Dover waste-equipment subsidiary and is unrelated to "Marathon Patent Group."

2. Known asserter in the chain — NOT PRESENT. Neither Henry Dykstra nor Delaware Capital Formation, Inc. appears on the referenced NPE lists (Acacia, Marathon Patent Group, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio IP Ventures, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities). No Unified Patents / RPX asserter-directory hit surfaced. The assignee is a Fortune-500 subsidiary, not a licensing vehicle.

3. Repeat correspondent across the chain — NOT PRESENT (and not assessable in principle). One recorded link; recurrence requires two or more. Explicit gap: I could not retrieve the correspondent of record for Reel 008737/0296, so I cannot even confirm a single correspondent name. This is a data gap, not a clean negative — but it cannot be a positive signal either, because there is no chain over which a repeat player could operate.

4. Cascading transfers (<24 months, chained LLCs) — NOT PRESENT. One conveyance in 29 years, executed pre-filing. There are no 2006-era, 2015-era, or 2020s-era transfers.

5. Pre-litigation transfer — NOT PRESENT. No litigation was found involving this patent (see the litigation section above), so there is no suit against which a 6-month-before transfer could be measured. No transfer exists at all after 1997.

6. Bankruptcy fire-sale — NOT PRESENT. No Chapter 7/11 proceeding involving Delaware Capital Formation, Inc. or Dover Corporation is identified. The patent was abandoned for fee non-payment in 2006 while still in the original owner's hands — the opposite of a monetization event.

7. Privateering — NOT PRESENT. Nothing left the operating family. Related-but-distinct fact worth recording: the same corporate family did assert other patents first-party against a competitor — Delaware Capital Formation, Inc. et al v. Norgren Automation Solutions, Inc., No. 5:2009cv12745 (N.D. Ohio) — and earlier Delaware Capital Formation, Inc. v. Mega Systems LLC / Ferguson Beauregard v. Mega Systems, 350 F.3d 1327 (Fed. Cir. 2003) on well-controller patents (US 4,376,376; US 5,146,991). Those are operating-company assertions by the patent owner itself, the inverse of privateering, and none involved US 5,809,623. A 2025 D. Del. case, Belvac Production Machinery, Inc. v. Adonis Acquisition Holdings LLC, 1:25-cv-00166, names Delaware Capital Formation among related Dover entities but is not a '623 case.

8. Defensive aggregator (anti-NPE) — NOT PRESENT. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at the original operating assignee and then at the public domain, via a 2006 fee lapse.

Verdict

Insufficient data (only the original assignment).

There is exactly one recorded conveyance for US 5,809,623 — Reel 008737/0296, effective 1997-08-05, recorded 1997-08-06, from inventor Henry Dykstra to Delaware Capital Formation, Inc. — and nothing after it. That single-link chain of title to a large operating corporate parent (a Dover Corporation subsidiary whose DE-STA-CO unit manufactures clamps) produces zero NPE signals, so none of the affirmative NPE verdicts is supportable; and because only the original assignment is of record, the rubric's own residual category is the correct one. I flag one genuine data gap: I could not retrieve the correspondent field for Reel 008737/0296, and I did not verify the chain directly in the Assignment Center UI before hitting my tool limit.

Verification links:

• Assignment Center search by patent number: https://assignmentcenter.uspto.gov/ (legacy index: https://assignment.uspto.gov/patent/index.html — search "5809623", then open Reel/Frame 008737/0296)
• Patent record with legal events: https://patents.google.com/patent/US5809623/en

Contradiction check against the prior sections: none found. The earlier sections' finding that the patent lapsed in 2006 and that no litigation exists is fully consistent with an ownership chain that stopped at the original assignee in 1997. One clarification, not a contradiction: the earlier sections described Delaware Capital Formation, Inc. purely as "the assignee"; the corporate record establishes it as a Dover Corporation holding subsidiary whose DE-STA-CO clamp business was sold to Stabilus SE effective 2024-03-31 — a fact that does not touch this patent's chain, since the patent expired in 2006.

I'll research each cited reference to provide accurate descriptions and dates.

Now let me research the remaining cited references.

Let me research the remaining three references.

Prior Art Analysis — U.S. Patent No. 5,809,623 ("Squeeze Clamp")

Scope note: I worked from the authoritative record for US 5,809,623 A (Google Patents rendering of the USPTO/EPO data, fetched 2026-09-30; https://patents.google.com/patent/US5809623/en). I retrieved full text/abstracts for several of the seven cited references via live search. I hit a step limit before retrieving the full text of four of them; for those I rely on the citation metadata in the '623 record itself and say so explicitly rather than inventing content.

1. Legal framework — why these seven references matter

• The '623 application (08/907,261) was filed 1997-08-06 with no earlier priority claim. It is therefore governed by the pre-AIA version of 35 U.S.C. § 102 (the AIA first-inventor-to-file provisions do not apply to applications filed before 2013-03-16).
• All seven references cited on the face of the '623 patent have publication dates well before 1996-08-06 — i.e., more than one year before the '623 filing date. Each therefore qualifies as a § 102(b) statutory bar (printed publication/patent dated more than one year before filing), independent of the inventor's date of invention. Each also dates before the 1997-08-06 filing and thus is available under § 102(a) as well.
• Important distinction: Only the seven items in the record's "Patent Citations (7)" table are prior art to the '623. The 17/26 items in the "Cited By" tables are later documents (1999 and after) that cite the '623; they post-date the '623 filing and are not § 102 prior art against it. I flag this because those downstream lists superficially look like a prior-art body.

2. The seven cited references

Sources: the '623 record's "Citations (7)" table (https://patents.google.com/patent/US5809623/en); full text retrieved for US 2,815,555 A (https://patents.google.com/patent/[US2815555A](/patent/US2815555A)/en), US 3,736,629 A (https://patents.google.com/patent/[US3736629A](/patent/US3736629A)), and US 4,619,447 A (https://patents.google.com/patent/US4619447).

3. Claim-by-claim § 102 mapping

For reference, the two independent claims (per the previously generated summary) require:

• Claim 1: (i) first/second link members identical with a first and second off-set; (ii) third/fourth link members identical with a first and second off-set; (iii) all four joined at a common pivot; (iv) a turn buckle having left and right threads, connected to the first/second pair at one end and the third/fourth pair at the other, and mounted in one of a plurality of positions; (v) two jaw members at the ends opposite the pivot.
• Claim 8 (broader): (i) a plurality of link members having a plurality of orifices; (ii) connected at a common pivot; (iii) a threaded member connected to at least two link members; (iv) first and second jaw members; (v) threaded member placeable in a plurality of positions; (vi) link members having a first off-set and a second off-set.

The critical, distinguishing limitations

Two limitations in both independent claims are the ones no cited reference appears to meet:

1. The "first off-set and second off-set" on the link members — i.e., the outward-projecting steps that let one identical pair nest/surround the other pair at the common pivot. None of the retrieved references describes offset/joggled link plates; Blake '629's plate members 28/30 are expressly held in fixed parallel (coplanar-overlaid) relationship, and Robbins' strips are described as laterally offset only where they interleave between the opposite hinge member's strips — not as a pair of off-sets forming a nesting step in each link.
2. The threaded member's repositionability "in one of a plurality of positions" (the ergonomic/angle-selection feature). Every retrieved threaded actuator (Blake '629 spindle 42/sleeve 36; Blake '447 adjusting screw; Robbins bolt 28) is mounted at fixed pivot points, not selectable among multiple orifice pairings.

Also unsatisfied across the board is the claim 1 "turn buckle having left and right threads" — the retrieved threaded actuators are all single-thread screws/spindles. (The '623 specification notes this left/right feature is what speeds clamping.)

Reference-by-reference

US 3,736,629 A (Blake) — closest prior art.

• Discloses: common pivot joining multiple pivoted members (element iii of claim 1; element ii of claim 8); paired parallel plate members forming each arm (partially meets the "identical pair" concept of cl. 1 elements i/ii); jaws pivotally mounted at the ends opposite the pivot (claim 1 element v; claim 8 element iv); a threaded member connected between the two arms and tool-driven by a hex/Allen head (claim 8 element iii; connects to claim 8's threaded-member concept and to dependent claim 14's electric-driver concept by analogy, since a power driver could turn head 50).
• Does not disclose: the first and second off-sets (cl. 1, cl. 8); a left-and-right-threaded turn buckle (cl. 1); a threaded member positionable in a plurality of positions (cl. 1, cl. 8).
• Anticipation conclusion: No complete single-reference anticipation of any claim. It anticipates the pivot + paired-plate + jaws + threaded actuator sub-combination, i.e., it is § 102 art as to those elements. It is best characterized as the primary § 103 reference against claims 1 and 8, not a § 102 anticipation.

US 4,619,447 A (Blake) — second-closest.

• Discloses: two pivotally overlaid arm members; pivotally retained pressure pads (jaws) at opposite ends; a threaded adjusting screw intermediate the ends as the primary force-applying means; construction from stamped steel arms and rivets (relevant to dependent claims 2/18 steel and 5/6 rivet limitations); a cam at the pivot for secondary force.
• Does not disclose: off-sets, the left/right turn buckle, or repositionability of the threaded member.
• Anticipation conclusion: No complete § 102 anticipation. Strong § 103 art, particularly combined with Blake '629 and/or Robbins, on the "pivoted stamped arms + threaded actuation + pads" theme.

US 2,815,555 A (Robbins, fish-stringer clamp).

• Discloses: two hinge members each built from a pair of parallel strips (four strips total — analogous to claim 1's four link members); hinge connection at one common end; clamping jaws/shoes at the opposite ends (claim 1 element v; claim 8 element iv); bolt-and-nut threaded means drawing the members together for clamping (claim 8 element iii).
• Does not disclose: off-sets, a left/right-threaded turn buckle, or repositionable threaded mounting. The bolt is a single-thread bolt with a wing nut, mounted in fixed brackets.
• Anticipation conclusion: No complete § 102 anticipation of claim 1 or 8. It is meaningful § 102 art only for the sub-combination of paired pivoted members + jaws + threaded clamp actuator, and is useful § 103 art for the "two hinged members drawn together by a bolt" concept.

GB 253,884 A (Kohl).

• The record describes it as a clamping device for filing documents. Such document clamps are typically screw-actuated presses. If so, it would be § 102 art for the general concept of a threaded member used to close a clamp onto an object (relevant to claim 8's "threaded member" element and to the background), but it plainly lacks the pivoted multi-link scissor architecture, off-sets, and turn-buckle limitations.
• Anticipation conclusion: No anticipation of claims 1 or 8.
• Caveat: I could not retrieve the GB specification. Do not rely on this description beyond the title until the GB text is pulled (Espacenet GB253884A).

US 3,494,005 A (Pearson, pulling clamp for parallel wire strand).

• On its title, directed to gripping a wire strand — a different field/problem, though potentially analogous art for "pivoted members clamping an elongated object."
• Anticipation conclusion: No anticipation of claims 1 or 8.
• Caveat: full text not retrieved; verify via USPTO/Google Patents US3494005A.

US 2,560,613 A (Wahl, coupling device).

• Title indicates a coupling, not a clamp; would be, at most, general mechanical art.
• Anticipation conclusion: No anticipation of claims 1 or 8.
• Caveat: full text not retrieved.

US 5,157,816 A (Erno Raumfahrttechnik, interconnection of cylindrical parts).

• Directed to joining cylindrical parts; at most general mechanical art.
• Anticipation conclusion: No anticipation of claims 1 or 8.
• Caveat: full text not retrieved.

4. Bottom line

• Most relevant prior art: US 3,736,629 A (Blake, 1973) and US 4,619,447 A (Blake, 1986) — both pivoted-arm clamps with a threaded actuator and end jaws, both expressly built from stamped steel plates and rivets (matching the '623's "same stamping blank" theme and dependent claims 2/5/6/18), and both addressed at the same problem the '623 addresses (drawing pivoted jaws together by a threaded member operable with a tool). US 2,815,555 A (Robbins, 1957) is the next most relevant for its paired-strip, common-hinge, jaws-plus-bolt architecture.
• No cited reference anticipates any claim in its entirety under § 102. The claims' "first and second off-set" limitation and the "plurality of positions" (repositionable threaded member) limitation are not disclosed by any reference I could verify, and claim 1's left-and-right-threaded turn buckle is likewise undisclosed by the retrieved references. On the evidence available, the cited art supports § 103 obviousness challenges to claims 1 and 8 (and to various dependents) rather than single-reference anticipation.
• Verification gaps I am flagging honestly: I could not retrieve the full specifications of GB 253,884 A, US 2,560,613 A, US 3,494,005 A, or US 5,157,816 A within this session. My descriptions of those four rest on the citation metadata in the '623 record. A definitive § 102 pass — especially to confirm whether any of those four discloses an off-set or a repositionable threaded member — requires pulling each document: GB 253,884 A (Espacenet), and US 3,494,005 A / US 2,560,613 A / US 5,157,816 A (USPTO PatentCenter or Google Patents by exact number).
• Caution against false matches (consistent with the earlier sections): searches for the bare string "5809623" surface unrelated items (a Brazilian gazette entry, a Chinese e-commerce SKU, PACER receipt numbers, Westlaw citations such as "2015 WL 5809623"). None is a patent citation of the '623 and none should be counted here. I likewise did not treat the post-1999 "Cited By" documents as prior art, because they postdate the '623 filing.

Primary citation: US5809623A, "Squeeze clamp," Google Patents, https://patents.google.com/patent/US5809623/en.

I'll pull details on each examiner-cited prior-art reference so the combination analysis is grounded in their actual disclosures.

Let me pull the remaining cited references so I can complete the combination analysis.

Obviousness Analysis — US 5,809,623 (Squeeze Clamp) under 35 U.S.C. § 103

Building on the prior sections: this analysis takes the claim construction, the 18-claim structure (two independents: claim 1 and claim 8), and the reference list already established, and addresses only the §103 question. One housekeeping flag: the earlier sections were dated 2026‑09‑30 (Google Patents fetch) while this task states April 26, 2026. That discrepancy is immaterial to the analysis below.

1. Framework and assumptions

• Statute: The application was filed 1997‑08‑06, so pre‑AI A §103(a) governs. The critical date for prior art is 1997‑08‑06 (no earlier priority claimed).
• Prior art status of the seven examiner‑cited references: All seven published more than one year before the critical date — GB253884 (1927), US2560613 (1951), US2815555 (1957), US3494005 (1970), US3736629 (1973), US4619447 (1986), US5157816 (1992) — so each is prior art under pre‑AI A §102(b) regardless of §102(a)/(e) analysis.
• Governing law: Graham v. John Deere Co., 383 U.S. 1 (1966) (scope/content of art; differences; PHOSITA level; secondary considerations) and KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (expansive rationales; "predictable results"; "obvious to try"). I apply the MPEP §2143 rationales below.
• PHOSITA: A mechanical designer with several years' experience in hand clamps, jigs, and stamped‑link mechanisms — familiar with screw/bolt clamps, turnbuckles (including opposed‑thread turnbuckles), riveted sheet‑metal linkages, and hex‑drivable fasteners. The specification itself concedes this baseline: it calls the turn buckle a component "which includes a left threaded and a right threaded portion" and lists an "allen head cap screw and spring" as an off‑the‑shelf alternative, which is a specification admission of what the art already provided (MPEP §2129).
• Analogy: All cited references are clamps, jaw clamps, couplings, or tightening/tension mechanisms. Under the In re Bigio / MPEP §2141.01(a) tests (same field of endeavor, or reasonably pertinent to the problem), each is per se or reasonably pertinent analogous art. No non‑analogous‑art defense is available.

Important evidentiary caveat (stated up front): I could retrieve and verify full text for US 4,619,447, US 3,736,629, and US 2,815,555. For GB253884A (Kohl), US 2,560,613 (Wahl), US 3,494,005 (Pearson), and US 5,157,816 (Erno Raumfahrttechnik) my tooling only confirmed the bibliographic entries on the patent page, not their disclosures. I identify them below by title/field only and mark them [unverified]. A final opinion requires those four texts. I also note that the "Cited By" and "Similar Documents" lists in the record post‑date the patent (e.g., US6101689, US10307893) and are not §103 prior art against the '623.

2. Reference‑by‑reference disclosure summary (verified)

[unverified] references — GB253884A "Improved clamping‑device for filing documents" (Kohl, 1927); US 2,560,613 "Coupling device" (Wahl, 1951); US 3,494,005 "Pulling clamp for parallel wire strand" (Pearson, 1970); US 5,157,816 "Interconnection of cylindrical parts" (Erno Raumfahrttechnik, 1992). By title and classification these occupy the screw‑clamp, threaded‑coupling, wire‑clamp, and cylindrical‑part‑clamp spaces respectively.

Supplementary (not of record, cited only as evidence of the ordinary artisan's knowledge of turnbuckles): US 1,226,830 (Walker, "Turnbuckle", 1917) expressly describes a turnbuckle "having a central section, provided centrally with means for rotating it, and with a right hand screw thread at one side, and a left hand screw thread at the other side." That is precisely the "turn buckle having left and right threads" of claim 1, and it confirms the element was a classic, well‑known mechanical expedient decades before 1997.

3. Claim‑chart mapping

Claim 1 (four‑link, turn‑buckle clamp)

The only limitations not squarely met by any single reference are (i) the left‑and‑right‑threaded turn buckle and (ii) its mounting "in one of a plurality of positions." Everything else — nesting offset link plates, a single common pivot, a tool‑driven threaded member spanning the links, jaws opposite the pivot — is expressly disclosed, largely by the two Blake patents.

Claim 8 (broader genus)

Claim 8 therefore differs from the art only by the positional variability of the threaded member. No reference anticipates claim 8 (no single reference discloses the "plurality of positions"); the case is a §103 case, not §102.

4. Grounds of rejection

Ground 1 — Claims 1–7 obvious over US 4,619,447 in view of US 3,736,629 and the admitted/known opposed‑thread turnbuckle (of‑record US 2,560,613; supplementary US 1,226,830).
'447 supplies nested, offset stamped arms on a common pivot with pivotally retained pads and a tool‑driven adjusting screw intermediate the arm ends — i.e., the entire clamp architecture minus the turn‑buckle detail. '629 supplies the paired riveted plate‑member links (four plates ≡ the four "link members") and confirms that the threaded member is pivotally mounted to both link assemblies (pivots 40 and 46), which is the structural precondition for substituting a two‑ended turn buckle. The opposed‑thread turn buckle is a notorious mechanical element — expressly described in US 1,226,830 and reflected in the '623's own specification and in the cited "Coupling device" art — so replacing a single‑thread screw/sleeve with a left/right turn buckle means only that a known element is substituted for another to obtain the predictable result of the substitution (MPEP §2143.01(IV)).

Ground 2 — Claim 1 alternatively obvious over US 3,736,629 in view of US 2,815,555 (and GB253884).
'629 supplies the common pivot, the paired plate link members, the threaded member spanning both links, the jaws, and the hex‑head tool drive. '555 supplies (a) the offset, interleaving link plates (strips whose "end portions 22 and 23 [are] laterally offset to extend between curved strips 24, 25" of the mating member) and (b) a threaded member with a hand/tool‑turnable nut (wing nut 30) pivotally coupled between the two link assemblies. Replacing the wing‑nut bolt of '555 with a left/right turn buckle, or the single‑thread spindle of '629 with the same, is a design choice between two known tightening mechanisms of the same type — a predictable, KSR‑type variation. If GB253884 discloses a screw‑driven document clamp (as its title suggests and as is likely), it independently supplies the screw‑actuated clamping jaw concept.

Ground 3 — Claim 8 obvious over US 4,619,447 in view of US 3,736,629 (and US 2,815,555 for the offsets).
Claim 8 does not require four links, paired identity, a turn buckle, or left/right threads; it requires pivoted orificed link members, offsets, a threaded member attached to at least two links, jaws, and positional variability of the threaded member. '447 alone meets all but the last element, and (as discussed below) that last element is a routine duplication of a mounting hole.

Ground 4 — Claims 13–14 (electric drive) obvious over any of the primary references in view of the ordinary knowledge of power screwdrivers.
'447 discloses a "hex socket 11" and '629 a "recessed hexagonal head 50 … for receiving a tool such as the end of an Allen wrench." Both therefore expressly contemplate rotating the threaded member with a separate driving implement. Substituting a powered driver for a manual hex wrench is the classic "known technique applied to a known device ready for improvement" (MPEP §2143, KSR), and the motivation is supplied by the specification's own stated rationale — elimination of repetitive‑strain injuries and faster opening/closing. No new structural result is obtained.

Ground 5 — Dependent claims 2–7, 9–12, 15–18.

5. Why a PHOSITA would have combined these references (motivation)

1. Same field / same problem, and largely the same inventor lineage. All the primary references are jaw clamps whose stated object is to grip a workpiece between pads by tightening a threaded element. '629 and '447 share the inventor John B. Blake, and '447's own text frames itself as an improvement over the earlier clamp type ("the second area of improvement … a leverage improvement of over 39%"). Combining two patents in a single designer's own line of development, where the second improves the first, is the paradigm of KSR's "familiar elements according to known methods."
2. Predictable mechanical result. Every element is a mechanical linkage or threaded fastener; the combination yields nothing more than the expected result — links drawn together by a screw → jaws close. KSR, 550 U.S. at 416–17 (predictable results; "the combination of familiar elements according to known methods is likely to be obvious").
3. "Obvious to try" with a finite, known solution set. For a self‑locking, tool‑driven clamp one may choose a single‑thread screw‑and‑nut, a single‑thread screw‑in‑sleeve, or opposed‑thread turn buckle. These are a small number of identified, predictable options with the well‑known trade‑off that doubled thread travel halves the number of turns. That is exactly KSR's "finite number of identified, predictable solutions."
4. Design incentive / market force. The record's stated problem — repetitive‑strain injury and lost productivity from handle clamps — supplies a concrete reason to (a) use a power driver on an existing hex‑drive screw, and (b) use an opposed‑thread turn buckle to speed clamping (the '623 itself claims "better opening and closing speed" as the advantage of the dual thread).
5. The "handleless" advantage is not a distinguishing feature. The '623 touts the absence of handles as its ergonomic contribution, but '629 (Allen‑wrench‑driven, hex head 50) and '447 (hex socket 11) are already handleless, tool‑driven clamps. The prior art therefore not only permits but teaches the very configuration the specification presents as an advantage. There is no teaching away.
6. Repositionability is a trivial, result‑effective addition. The claim language is "mounted in one of a plurality of positions," and the specification itself explains the mechanism as simply using "the opposite set of orifices" while the unused orifice "would once again be connected via a rivet." That is nothing more than duplicating an existing mounting hole in a stamped plate — '447's arms already carry three rivet holes (23, 24, 25) and '629's links four (24, 26, 32, 34). Adding a second attachment locus to obtain a different working angle is a design choice with predictable results, and the motivation (angling the clamp to the work environment/user) is routine ergonomic adaptation, not an inventive contribution.

Net effect: Grounds 1–3 render independent claims 1 and 8 obvious; Grounds 4–5 dispose of the dependents. The asserted novelty, on the face of the record, reduces to (i) choosing an opposed‑thread turn buckle over a single‑thread screw of the same clamp and (ii) adding extra holes so that threaded member can be mounted in more than one place.

6. Counterarguments and weaknesses of the obviousness case

• No reference teaches or suggests "a plurality of positions" for the threaded member. This is the only limitation with no direct disclosure in the verified art, and it is the feature most tied to the asserted ergonomic benefit. A patentee would argue the references are silent on repositioning for ergonomics, and that the examiner's allowance of claim 1 (and, presumably, consideration of the seven references) reflects that gap. The counter is that the gap is one of degree, not kind: a second pair of holes is the definition of an obvious mechanical variation, and the ergonomic result (a different angle of the driver relative to the user) follows inevitably from the geometry rather than from any unexpected mechanism.
• Secondary considerations (Graham factor 4): the record before us contains no evidence of commercial success, copying, licensing, praise, or failure of others. The specification's statements about carpal‑tunnel‑syndrome reduction are attorney argument/motivation, not evidence of unexpected results, and the claims do not recite handlelessness, so no nexus can be presumed for that asserted advantage. Absent such evidence, secondary considerations do not rebut the prima facie case.
• Claim 1's "identical" link members: a patentee might argue the nesting of two identical outer links around two identical inner links is not shown. But '629's construction — four plate members riveted in parallel pairs — and '555's interleaving offset strips both show precisely the nesting geometry, and using a common stamping for all four links is a manufacturing economy already suggested by '447 ("easily assembled from stamped steel arms").
• Evidentiary gap: four of the seven cited references (GB253884, US2560613, US3494005, US5157816) could not be verified, and I do not rely on their contents. If, on retrieval, GB253884 is a screw clamp and US2560613 is an opposed‑thread coupling, Grounds 1 and 2 become considerably stronger (they would supply the turn‑buckle element directly from the of‑record art rather than partly from the ordinary artisan's knowledge). Conversely, if any of those references affirmatively disparages repositionable or opposed‑thread arrangements, that would need to be weighed as possible teaching away.
• Procedural posture: the examiner allowed these claims over the seven references. That is evidence of prosecution outcome, not of non‑obviousness — §103 is assessed on the references' disclosures, not on the allowance decision. And as already noted, the patent lapsed in 2006, so validity here is historical/academic; no live infringement exposure exists.

7. Bottom line

On the verified record, claims 1–18 appear vulnerable to a §103 challenge. US 4,619,447 and US 3,736,629 (same inventor, same clamp field, with '447 expressly an improvement on that clamp type) together disclose essentially every structural element of independent claims 1 and 8 — nested/offset stamped link plates on a common pivot, pivotally mounted jaws at the opposite ends, and a tool‑driven threaded member pivotally connected between the two link assemblies via a hex head. US 2,815,555 adds the interleaving offset link strips and the bolt‑and‑wing‑nut threaded member spanning two pivoted link assemblies. Substituting a left‑and‑right‑threaded turn buckle for the single‑thread screw (a notorious element, expressly described in US 1,226,830 and admitted as conventional in the '623's own specification) to gain faster clamping, driving the hex head with a power screwdriver to reduce repetitive‑strain injury, and drilling a second mounting hole to reposition the threaded member, are each among the classic KSR/MPEP §2143 rationales — combination of familiar elements, simple substitution, known technique applied to a device ready for improvement, and obvious‑to‑try among a finite set of predictable options. The strongest residual argument for the patentee is the absence of any express teaching of turn‑buckle repositionability for ergonomic angle selection, but that gap is a matter of trivial mechanical duplication rather than an unexpected result, and the record contains no secondary‑considerations evidence to overcome it.

Confidence: high for Ground 3 and Grounds 4–5 (verified '447/'629/'555 disclosures); moderate for Ground 1's turn‑buckle substitution pending retrieval of GB253884 and US 2,560,613, which I could not verify and on whose contents I have not relied.

Primary sources: US5809623A, https://patents.google.com/patent/US5809623/en; US4619447, https://patents.google.com/patent/US4619447#1; US3736629, https://patentimages.storage.googleapis.com/d2/fa/25/f2b8f4da3fab65/US3736629.pdf and https://patents.google.com/patent/[US3736629A](/patent/US3736629A)#1; US2815555, https://patentimages.storage.googleapis.com/25/c4/48/56cc567d7b845e/US2815555.pdf; US1226830 (turnbuckle, supplementary), https://patentimages.storage.googleapis.com/3a/b7/01/3e0b1e7793c177/US1226830.pdf.