US 6669037

I'll search for litigation and docket information on this specific patent number, while relying on the authoritative patent text provided.

US Patent 6,669,037 — Verification Note

I was able to confirm the patent itself against the authoritative full text of the Google Patents record for US6669037B1 (fetched 2026‑09‑29) plus one corroborating secondary source (the USPTO Official Gazette text for the related patent US 6,935,523 B2, mirrored at the Indiana University virtual disk library: https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/[5705037](/patent/5705037)/FID2835/OG/html/1297-5/us06935523-20050830.html).

On the requested database searches: My web searches returned no results for any US district court litigation, ITC proceeding, PTAB trial, or Court of Appeals for the Federal Circuit (CAFC) 2026 docket involving patent 6,669,037. I also found no assignment or enforcement activity beyond the original 2002 assignment. I cannot rule out the existence of such a docket — searches were web‑based, not a direct query of PACER, the CAFC docket system, or USPTO Patent Center — so treat that as "not found," not "does not exist." If you need a definitive litigation check, a direct PACER/CAFC CM/ECF query would be required.

Bibliographic Data (from the authoritative record)

Related family member: US 6,935,523 B2 (application 10/421,524, filed April 22, 2003, granted August 30, 2005) is a continuation‑in‑part of this application and is noted as subject to a terminal disclaimer.

Discrepancy flagged (not corrected): The Official Gazette text for US 6,935,523 states it "claims priority of provisional application 60/349,940, filed on Jan. 18, 2001," while the US 6,669,037 record states the priority date as January 18, 2002 (consistent with the title‑page priority date "2002‑01‑18"). Per operating rules I have not auto‑corrected either value; the year "2001" in the OG text appears anomalous but I cannot authoritatively resolve it.

Abstract (as issued)

"Modular display racks, which are easily configurable, have interchangeable components, and are capable of being packaged and shipped in small containers, are described. Preferred methods for using modular display racks are also disclosed."

Plain‑Language Overview of the Independent Claims

Claim 1 — The core modular rack.
A display rack built from two halves. The upper rack portion has at least two "ladder racks," each carrying at least one receiving channel made of a base, two sides, and an open receiving slot. A lateral support bar slides down between the two sides and into the open slot of each ladder rack's channel, thereby coupling the ladders together in a detent‑like, removable way. The lower base portion has at least two base bars, each with two ends and a center load‑bearing piece sitting between those ends; at least one part of that load‑bearing piece runs perpendicular to a part of the base bar (i.e., load is carried on a differently‑oriented surface). In short: ladders joined by drop‑in bars, and base bars with a perpendicular central support pad.

Claim 9 — The expandable end‑ladder configuration (structural).
A rack with first and second end ladder racks on first and second end stabilizer bars. The two end ladders are joined when a first lateral support bar's two male tabs each engage a slot in a receiving channel on each ladder. The two stabilizer bars are joined when a cross‑bar telescopes over a joining bracket on the side edge of each stabilizer bar. The rack is expandable by inserting a center ladder rack between the end ladders and a center stabilizer bar between the end stabilizer bars; when expanded, the lateral support bar sits between an end ladder and the center ladder, and a second lateral support bar sits between the other end ladder and the center ladder. This is the claim that captures the "grow from two towers to three" concept.

Claim 15 — The method of installation.
A four‑step assembly method: (a) couple a removable cross‑bar with two open ends onto two joining brackets attached to two different stabilizer bars; (b) fasten a ladder rack to each stabilizer bar at the center load‑bearing piece; (c) removably couple the two ladders to one another via a lateral support bar engaging a receiving channel on each ladder; and (d) the receiving channels each have two sides and a base, with the lateral support bar resting on the base between the two sides while engaging both channels. (Claims 16–18 add tabs on the bar ends, the non‑coplanar three‑edge slot geometry, and telescoping/fastener details.)

Claim 19 — The "kit of removable components" claim.
Frames the rack as a set of interchangeable parts: a first and second ladder rack each with a bracket; a first and second base bar, each having an edge and a load‑bearing piece for holding a ladder upright, where the base‑bar edge and the load‑bearing‑piece edge are generally perpendicular; a lateral bar bridging the two ladder racks via their brackets; and a cross bar bridging the two base bars via brackets on the load‑bearing pieces — the whole assembly being reconfigurable by engaging or disengaging the removable components. This is the broadest "modularity" claim, drafted to cover the component set rather than one fixed geometry.

Key Technical Points Supporting the Claims

• The "U‑shape bracket" (claim 4/11/13/20): a steel channel with two sides and a base; the base terminates short of the rear attachment face, forming the receiving channel/slot that the lateral bar's engagement tip (male tab) drops into — the detent‑like joint.
• The joining bracket (claim 9/15/18): an extended L‑shaped bracket (tall side + short side) welded at the axial end of the center load‑bearing piece, with nuts welded on as bolt‑gripping points; the cross‑bar telescopes over it and is bolted through cross‑bar holes. The short side reduces friction during telescoping.
• Modularity claim from the specification: a triple‑tower rack reduces to a double by removing the center ladder, two pairs of lateral support bars, the center stabilizer bar, and one cross‑bar; it expands to four towers by adding those components — eliminating pre‑welded multi‑tower inventory.
• Named prior art cited on the face: US 3,212,648; 3,512,654; 3,602,374; 3,730,108; 3,871,784; 3,937,329; D327,993; 5,779,065; 5,653,349; 5,660,637; 6,129,224; 5,894,945; 5,887,731; 6,029,833; 6,240,687; US 2003/0034320 A1; and US 6,561,366 B2.

Uncertainty / Caveats

• Litigation and CAFC 2026 activity: no authoritative information found. Nothing in my searches indicates an appeal, IPR, or 2026 Federal Circuit docket for this patent. This is a negative search result, not a confirmed absence.
• Priority‑year discrepancy (2001 vs. 2002 for provisional 60/349,940) noted above and left unresolved.
• Assignee address variants: the Google Patents record lists "LA Display Fixture Inc" without a city in the header, while the assignment and OG text give Los Angeles/California. I have used the assignment record's "Los Angeles, California."
• The patent has been expired since December 30, 2015, so any 2026 enforcement activity would have to concern the live continuation‑in‑part US 6,935,523 B2 or other family members, not US 6,669,037 itself.

I'll search for litigation involving US patent 6669037.

Let me search more specifically for the patent owner and litigation databases.

Let me check the Unified Patents litigation portal and do a few more targeted checks.

Bottom line

I found no litigation involving U.S. Patent No. 6,669,037 (the Ahn "Modular display rack system" patent). Based on the sources I could search, the patent appears never to have been asserted in a U.S. district court, the ITC, the Federal Circuit, or challenged at the PTAB. I want to be explicit that this is a negative finding from limited searching, not a certified clearance.

What I searched

The only litigation-adjacent activity reflected in the patent's own record is a continuation-in-part relationship, not a dispute:

• US 10/421,524 → US 6,935,523 B2 ("Modular display rack system," Ahn, assigned to LA Display Fixture, Inc.), filed 2003-04-22, granted 2005-08-30, and subject to a terminal disclaimer. Google Patents lists 6,669,037 as Cited By for this family member.

⚠️ Common false positive — do not conflate

A frequently returned hit for a "6,6xx,037" query is U.S. Patent No. 6,699,037, the Align Technology patent challenged by ClearCorrect Operating, LLC in an IPR petition (announced December 1, 2015). Per the strict instruction to interpret identifiers literally, 6,699,037 ≠ 6,669,037 — different patent, different owner (Align Technology, not LA Display Fixture), different technology (orthodontic aligners). It is not litigation against US 6,669,037 and I have excluded it.

I also saw several unrelated cases refer to an "'037 patent" (e.g., an Aptiv v. Microchip '037 patent in D. Del., and Wilus/HP '037 patent references). Those are different patents entirely and are likewise excluded.

Related status facts from the patent's own record

• Assignee/owner of record: LA Display Fixture, Inc. (assignment recorded 2002-07-08; assignor Chong Youn Ahn). No subsequent assignment to a litigation-oriented entity (i.e., no apparent NPE acquisition) appears in the record.
• No reexamination or PTAB proceeding appears in the record.
• Terminated early: maintenance fee lapse. REMI mailed 2015-08-07; LAPS 2015-12-30; "Patent expired due to nonpayment of maintenance fees" recorded 2016-01-22/2016-01-25; FP effective 2015-12-30. The stated anticipated expiration is 2022-04-04.
• Because the patent lapsed in late 2015, any enforcement window would have been limited to roughly 2003–2015 — and nothing in the record suggests it was used.

Caveats on my confidence

1. My searching was search-engine based; I could not run a direct docket query against PACER/CourtListener's RECAP archive, Docket Navigator, Lex Machina, or the Unified Patents portal.unifiedpatents.com/litigation/caselist interface, which may require interactive access I don't have here.
2. A negative search result is not proof of absence. Small, closed, or settled suits — particularly state-court or non-published cases, and pre-2015 filings not well indexed — could exist without surfacing.
3. The patent is a consumer/retail display-fixture patent expired since 2015, which makes litigation exposure and indexing both low.

If you need a defensible clearance statement, I'd recommend running the number directly through Docket Navigator, Lex Machina, or the Unified Patents litigation portal, and pulling the full patent family (including US 6,935,523) to check for any co-pending assertion.

I'll verify the structured "no proceedings" default against live sources before finalizing.

Two searches returned only false positives (different patents with the digits "6669037" embedded in larger numbers, e.g., US 11,673,903). Let me run a couple of tighter checks.

Proceedings overview

Zero AIA trial proceedings are on file for US 6,669,037. The structured "PTAB proceedings on file" block is populated from the USPTO Open Data Portal and returned no IPR, PGR, or CBM for this patent; my independent web checks surfaced no petition, institution decision, Final Written Decision, or Federal Circuit appeal naming this patent. The breakdown is therefore 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials — but the bottom line for a defendant is not "the patent has survived two IPRs and is hardened." It is the opposite: this patent lapsed for nonpayment of maintenance fees on 2015-12-30 and expired before anyone ever bothered to challenge it, so the defensive posture is "expired and unenforceable for any post-2015-12-30 conduct," with no PTAB record to lean on or worry about.

Proceeding-level detail

There are no proceedings to profile. Rather than manufacture the per-proceeding sections, here is the verification trail and an explicit flag on the near-miss identifiers my searches returned:

False positives flagged (do not confuse these with a proceeding on 6,669,037):

• US 6,699,037 (Align Technology) — ClearCorrect IPR petition reported 2015-12-01. Different patent (7-digit, different owner, dental aligners). Align press release
• US 11,673,903 (Inpria/Entegris), IPR2025-00267 — a digit-substring match only. Different patent entirely.
• US 9,460,037 (Aptiv v. Microchip, E.D. Pa.) — same substring trap, different patent.

No petitioner, panel, grounds, institution date, FWD, settlement, or appeal docket number exists to report for US 6,669,037, and I will not invent one.

Strategic summary

Claim status: all 20 claims UNTESTED at the PTAB — but the enforcement horizon has closed. No claim of US 6,669,037 has been canceled, confirmed, or even construed in an AIA trial. Claims 1–20 (including independent claims 1, 9, 15, and 19 and their dependents) therefore stand in their as-issued form. That would normally be a caution flag for a defendant. Here it is not, because the patent is dead: Google Patents' legal-events record shows a "Lapse for failure to pay maintenance fees" coded 2015-12-30, "PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362" recorded 2016-01-22 and 2016-01-25, and a final "Lapsed due to failure to pay maintenance fee" with an effective date of 2015-12-30. Maintenance fees had been paid at the 4-year (2007-05-24) and 8-year (2011-06-02) intervals; the 12-year fee was not. The 2022-04-04 "anticipated expiration" entry in the same record is the nominal 20-year term and is superseded by the 2015 lapse. US6669037B1 on Google Patents

Estoppel landscape: none, and largely academic. Because no IPR was ever instituted, no petitioner is carrying § 315(e)(2) estoppel, and no prior-art ground has been "used up." The 16 references cited during prosecution (e.g., US 5,779,065 to Trion; US 6,129,224 to Ohra Regalanlagen; US 3,870,784; US 6,240,687) remain fully available to anyone who wants to mount a § 102/§ 103 invalidity theory in a declaratory-judgment or defensive posture, subject only to the ordinary § 282 burden. Practically, though, an IPR on an expired patent is a poor investment: institution is legally possible (the Board has instituted on expired patents, construed under Phillips), but there is no ongoing infringement to enjoin and the damages tail is closing, so the cost-benefit rarely justifies the filing fee. Note also that the AIA vehicles other than IPR were never available here — PGR requires an effective filing date on or after 2013-03-16 (this patent claims priority to provisional 60/349,940, filed 2002-01-18), and CBM requires a claim covering a financial product or service (a display rack does not), and the CBM program sunset on 2020-09-16 anyway.

Pattern signals: none — and that is itself the signal. No serial petitioner, no defensive aggregator (no Unified Patents petition), no patent-owner appeal activity. US 6,669,037 was IPR-eligible from 2012-09-16 and remained in force until 2015-12-30, a window of over three years during which not one third party filed. That absence is consistent with a low-value, non-asserted patent in a narrow furniture niche. For context, the patent has a continuation-in-part sibling, US 6,935,523 (from application 10/421,524, filed 2003-04-22, same inventor/assignee, subject to a terminal disclaimer), which claims a different structure (base bar pivotally attached via a pivot pin) — it is a separate patent with a separate validity and term profile and should be cleared independently before you rely on this analysis. US 6,935,523 grant record

Recommended next steps

• Attack the timeline first, not the merits. If you are holding a demand letter citing US 6,669,037, identify the accused conduct dates. Conduct occurring after 2015-12-30 cannot infringe, because the patent rights ended when the 12-year maintenance fee went unpaid. Even for pre-expiry conduct, 35 U.S.C. § 286 bars recovery for infringement more than six years before the complaint was filed — and infringement stopped no later than 2015-12-30 — so a suit filed after 2021-12-30 recovers nothing. (Laches is unavailable post-SCA Hygiene, but § 286 is a hard statutory bar.)
• Verify the lapse before you rely on it. Fee lapses can be cured by a petition to accept an unintentionally delayed payment under 37 CFR 1.378 with the surcharge, and the PTAB record can be corrected by a later event. Pull the current fee/status history for US 6,669,037 through Patent Center / the USPTO Open Data Portal and confirm no reinstatement petition was granted after the 2016-02-16 lapse entry.
• Confirm the PTAB docket yourself, since absence of evidence is the whole point. I checked the canonical ODP block plus live web sources and found nothing. You can independently confirm at USPTO PTAB Center and the PTAB Open Data API; there is no Federal Circuit or CourtListener docket for this patent to link because no FWD was ever issued and thus no appeal could arise. The absence of any PTAB activity on a patent that was IPR-eligible for three-plus years is a strong signal of low assertion value — but here the dispositive defense is expiry, not procedural history.
• Check the sibling and the prior-art estate. Separately clear US 6,935,523 and any other Ahn/LA Display Fixture continuations for their own status and term; a demand letter citing "the '037 family" may be reaching for the still-different C-I-P claims.

Caveat on every date above: the 2015-12-30 lapse and 2016-01-22/25/2016-02-16 confirmations are taken verbatim from the Google Patents legal-events table in the authoritative record provided, and Google expressly disclaims that its legal status is "an assumption ... not a legal conclusion." Treat these as strong leads, not as a certified USPTO status printout.

I'll research the assignment chain, correspondent of record, and assignee status.

Let me dig for the correspondent of record and any additional recorded assignments.

Assignment & Ownership Analysis — US 6,669,037

⚠️ Sourcing note up front: I was able to confirm bibliographic and assignment summary data, but I could not retrieve the raw USPTO Assignment Center record itself (the reel/frame record's correspondent field, attorney/agent name, and full assignor/assignee addresses). Google Patents reproduces the reel/frame and conveyance, but not the correspondent. Live searches for the reel number returned nothing relevant, and my tool budget was exhausted before I could reach an Assignment Center lookup. The Correspondent line below is therefore "unverified / not retrieved," not "none recorded." Treat that gap as the main limitation of this report.

Inventors

Pattern check — co-inventor departures: Not applicable / not present. This is a single-inventor patent. There is no co-inventor cohort that could "depart within 12 months of filing." Note the structural point instead: the inventor and the assignee principal appear to be the same person, which is the classic small-operating-company pattern (founder assigns to his own company) rather than a fire-sale precursor.

One caveat: Ahn's residence is given inconsistently across sources (Redondo Beach vs. Los Angeles). Both are consistent with a southern-California retail-fixture operator and do not indicate a transfer of rights.

Original assignee

LA Display Fixture, Inc., Los Angeles, California (assignment recorded 2002-07-08; assignor Ahn; executed 2002-06-28; reel/frame 013071/0258 — Reel 013071, Frame 0258).

• Primary line of business: wholesale store fixtures — display racks, mannequins, showcases, hangers. SIC/industry listing: "Wholesale – Store Fixtures" (D&B). Addresses of record in directory data: 1227 S San Pedro St., Ste. 1, Los Angeles, CA 90015 (Fashion District; ladisplay.com) and a second listing at 2025 S Central Ave, Los Angeles, CA 90011.
• Did they ship a product embodying the claims? Likely yes, but I could not independently confirm the specific SKU. The specification is written from the manufacturer's perspective ("from a rack manufacturer's standpoint… simpler inventory, easier to package and ship via UPS® and Federal Express®"), the assignee is a fixture wholesaler, and the inventor is the company principal. That is strong circumstantial evidence of commercial embodiment, but I have no photographic, catalog, or retail listing tied to claim 1's specific channel/base-bar geometry. Stated as "probable," not confirmed.
• Current status: Appears to be operating. Directory listings are current (phone 213-748-2638; ladisplay.com; a live map listing with business hours). D&B shows two different records with conflicting scale figures — one at 1227 S San Pedro (~$1.9M revenue, 12 employees) and one at 2025 S Central Ave ($140K revenue, ~2 employees). No evidence of acquisition, dissolution, or bankruptcy was found. Entity is a California corporation, not a Delaware/Texas single-purpose LLC — relevant to the shell-entity analysis below.

Assignment timeline

Exactly one recorded assignment exists for this patent in every source I could reach.

• 2002-06-28 (executed) / recorded 2002-07-08 — Reel 013071/0258
  • Conveyance: Assignment — "ASSIGNMENT OF ASSIGNORS INTEREST" (USPTO code AS)
  • Assignor: Ahn, Chong Youn (sole inventor)
  • Assignee: LA Display Fixture, Inc. (Los Angeles, California)
  • Correspondent: ⚠️ Not retrieved. The reel/frame, execution date, recording date, and effectiveness date (2002-06-28) are confirmed; the correspondent attorney/firm of record is not present in any source I could access. This is the one field the task specifically asked me to capture and I cannot honestly supply it. Per the operating rules, I will not guess a firm name.
  • Context: Founder-to-own-company assignment at filing time (inventor assigns to the small operating business he runs), i.e., a routine original-assignee recording, not an acquisition. Note it was executed after the April 4, 2002 filing and recorded ~3 months post-filing — common for small filers using a short-form assignment rather than the application-data-sheet route.

After that: no further recorded assignments. No security agreement, no release, no change of name, no merger, no license recordation, and no transfer to any LLC or holding entity appears in the Google Patents Legal Events table (which shows only AS 2002, FPAY 2007, FPAY 2011, REMI 2015-08-07, LAPS 2015-12-30, STCH 2016-01-22/2016-01-25, FP effective 2015-12-30). The title therefore never left LA Display Fixture, Inc.

Family cross-reference (same owner, not a transfer): The continuation-in-part US 6,935,523 B2 (application 10/421,524, filed 2003-04-22, granted 2005-08-30) is also assigned to LA Display Fixture, Inc. and names the same sole inventor (USPTO Official Gazette text, mirrored at the Indiana University virtual disk library: https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/[5705037](/patent/5705037)/FID2835/OG/html/1297-5/us06935523-20050830.html). The prior "Patent summary" section flagged a priority-year discrepancy on this CIP (OG says provisional 60/349,940 filed Jan. 18, 2001; this patent's record says Jan. 18, 2002). That discrepancy is unresolved and does not affect the assignment chain — the CIP's assignment is to the same operating company either way.

Link for verification: https://assignmentcenter.uspto.gov/ (search patent number 6669037; equivalent index at https://assignment.uspto.gov/patent/index.html). The record should return a single hit, reel 013071 frame 0258.

Timeline diagram

timeline
    title Ownership of US 6669037
    2002 : Provisional 60349940 filed Jan 18
         : Application 10117572 filed Apr 4
         : Ahn assigns to LA Display Fixture
         : Recorded Jul 8 reel 013071 frame 0258
    2003 : Patent US6669037 granted Dec 30
         : CIP filed Apr 22
    2005 : CIP US6935523 granted Aug 30
    2015 : 12 year fee not paid Dec 30
    2016 : Patent lapsed Jan 22

NPE / troll-pattern signals

One clarifying note on signal 8 / expiry: This patent was a hard-blocking right against competitors' modular racks for ~12 years (granted 2003-12-30 to lapse 2015-12-30), yet nothing in the record shows it was ever asserted. Expiry here is fee lapse by a small operating company, not neutralization by a defensive aggregator — those are different findings and I am not conflating them.

Verdict

Insufficient data — in the literal sense defined by the rubric: the chain consists of nothing but the original assignment, and the one field that could carry a signal (the correspondent of record on reel 013071/0258) could not be retrieved.

Two qualifications so this isn't misread as an alarm:

1. This is a clean, non-NPE chain, not a murky one. Every affirmative NPE signal is not present: a single 2002 founder-to-company assignment (reel 013071/0258, executed 2002-06-28, recorded 2002-07-08), no subsequent transfers, no shell LLC, no known asserter, no bankruptcy, no defensive aggregator, and — per the prior litigation section — no assertion ever filed. The ownership never moved off the operating company.
2. The "insufficient data" call is driven solely by the missing correspondent field, not by ambiguity about who owns the patent. Ownership is unambiguous: LA Display Fixture, Inc. is the sole owner of record from 2002-07-08 through lapse (effective 2015-12-30).

Recommended next step for a defensible statement: run patent 6,669,037 and application 10/117,572 directly through https://assignmentcenter.uspto.gov/ to capture the correspondent attorney/firm on reel 013071/0258, and confirm there is no second (e.g., security-agreement) record that Google Patents' Legal Events table might have omitted. Given that the patent expired 2015-12-30 for nonpayment of maintenance fees and no assignment ever departed the original assignee, the probability that this step changes the verdict is low.

I'll verify the patent number and gather details on its cited prior art.

Let me gather details on additional cited references.

Prior-Art Analysis — US 6,669,037 B1 ("Modular display rack system")

1. Exact-number verification (no auto-correction)

I searched for the literal string 6669037. The only record returned is:

Excluded look-alikes (per the strict no-auto-correct rule): US 6,699,037 (Align Technology, orthodontic aligners — the ClearCorrect IPR patent) and other "'037 patents" surfaced by search engines are different numbers and different patents. They are not this patent and are not used below.

Search-method caveat: verification was done via the Google Patents record (which mirrors USPTO bibliographic/data) plus a corroborating USPTO Official Gazette transcription for the family member US 6,935,523. I did not run an interactive USPTO Patent Center / Patent Application Locator query, so treat this as web-sourced confirmation of the exact number, not a certified database extract.

2. What the 17 cited references are (and are not)

US 6,669,037 lists 17 "Patent Citations" on its face (16 in the "Citations" table + US 6,561,366 B2). These are examiner-considered references under 35 U.S.C. § 102(a)/(b)/(e), not adjudicated anticipations.

Overall conclusion up front (flagged explicitly): On the record available, no single cited reference appears to disclose every element of any independent claim (1, 9, 15, or 19) in a single structure, which is what § 102 anticipation requires. The citations are, for the most part, element-level art — U-shaped/receiving brackets, telescoping joints, modular knock-down frames, and keyhole/slot fastening — that would more properly support a § 103 obviousness combination than a § 102 rejection. Below I map, element-by-element, which claims each reference could potentially anticipate if its disclosure were read most broadly, and I flag where that reading is a stretch. If a reference's full text was not retrievable in this session, I say so.

3. Reference-by-reference analysis

Group A — Cantilever / bracket-and-slot racks (closest to the "receiving channel" limitation)

1. US 3,212,648 A — "Cantilever rack"

• Inventor: Baker et al.; Assignee: Palmer-Shile Co.
• Priority/filed: 1963-11-18; Published: 1965-10-19
• Description (verified from full text): Tapered columns with inclined rectangular apertures; load arms carry channel-shaped (U-shaped) brackets that fit around the column; rectangular pins pass through aligned apertures in the bracket and column, wedging the bracket against the column. Several columns may be interconnected.
• § 102 exposure: § 102(b) (published >35 years pre-filing). Potentially relevant to claim 4/20 (U-shape bracket with base and two sides) and to the broad "channel + removable engagement" concept of claim 1 — but the bracket embraces the column rather than receiving a drop-in bar, so it does not anticipate the lateral-support-bar-in-open-slot limitation. Best characterized as § 103 art against claims 1/4.

2. US 3,602,374 A — "Cantilever rack"

• Assignee: Westeel Rosco Ltd.
• Priority/filed: 1969-04-04; Published: 1971-08-31
• Description: Cantilever rack of the column-and-arm type with releasable arm-to-column engagement (background art in the same family as the Palmer-Shile citation).
• § 102 exposure: § 102(b). Same weakness as US 3,212,648 — arm/bracket-to-upright engagement, not a ladder-to-ladder drop-in lateral bar. Element-level art for claim 1 (base bar + load-bearing structure) at most; likely § 103.

3. US 6,129,224 A — "Cantilever type shelf"

• Inventor: Christian Mingers; Assignee: Ohra Regalanlagen GmbH
• PCT filed 1996-09-17; § 371 date 1999-05-17; Published: 2000-10-10
• Description (verified): T-section uprights with cut-out pairs; cantilever brackets end in a base plate with two hooks (male tabs) that are horizontally insertable through a cutout pair; a securing element is received in an opening in each hook. Base plate is U-shaped in cross-section (cross-piece + longitudinal webs).
• § 102 exposure: § 102(b). This is the strongest structural match to the tab-and-slot engagement language of claim 9 ("a first lateral support bar comprising two male tabs each engages a slot in a receiving channel") and to claim 12/16 (two male tabs / protruding ends). However, US 6,129,224's hooks engage cutouts in a flange, not a U-shaped receiving channel with a base and two sides as in claims 1/4/15(d)/20, and it lacks the ladder-rack, center-load-bearing-piece, and stabilizer-bar/cross-bar limitations. So: potentially anticipates nothing outright; strong § 103 art for claims 1, 4, 9, 12, 16.

4. US 3,512,654 A — "Modular cantilever adjustable arm rack and joint assembly"

• Assignee: Jarke Corp.
• Priority/filed: 1968-05-09; Published: 1970-05-19
• Description: Modular (knock-down) cantilever arm rack with a specific arm-to-post joint assembly.
• § 102 exposure: § 102(b). Directly on point for the modularity/reconfigurability theme of claim 19 ("modular display rack comprising a plurality of removable components") and for the broad concept of claim 1, but it is a cantilever storage rack, not a ladder-and-lateral-bar merchandise rack. § 103 art for claims 1 and 19.

Group B — Adjustable-shelving / bracket-support art

5. US 3,730,108 A — "Adjustable shelving structure"

• Inventor: A. Stroh; Priority/filed: 1971-04-26; Published: 1973-05-01
• Description: Adjustable shelving with interchangeable/repositionable shelf supports.
• § 102 exposure: § 102(b). Element-level relevance to the removable-coupling concept in claims 1 and 19; no receiving-channel-with-open-slot, no telescoping joining bracket. § 103 only.

6. US 3,871,784 A — "Bracket support structure"

• Inventor: James Van Horn; Priority/filed: 1973-03-21; Published: 1975-03-18
• Description: Bracket support structure for racks/shelving (bracket-to-upright engagement).
• § 102 exposure: § 102(b). Background art for the bracket/engagement limitations of claims 1, 4, 15(d), 20. § 103 only.

7. US 3,937,329 A — "Sheet glass supporting rack"

• Assignee: Cobbledick-Kibbe Glass Company; Priority/filed: 1974-08-12; Published: 1976-02-10
• Description: Rack with a base structure for supporting sheet goods (base bars / load-bearing base frame).
• § 102 exposure: § 102(b). Potentially relevant only to the "at least two base bars, each having two ends" limitation of claim 1 and the base-bar/load-bearing-piece geometry of claim 19. No ladder racks, no lateral support bar. § 103 only.

Group C — Keyhole / slot / stud fastening (the "detent-like" joint)

8. US 5,653,349 A — "Offset stud fastener"

• Assignee: Akro-Mils; Filed 1995-07-31; Published: 1997-08-05
• Description (verified): A stud fastener and an assembly (illustrated as a bin rack) in which a rigid sheet with elongated openings is joined to a rigid sheet with keyhole-shaped openings; the openings have first/second/third portions of differing width so the stud passes through in one orientation and locks in another. Includes step-by-step assembly/disassembly of the rack.
• § 102 exposure: § 102(b). This is the closest art to the "open receiving slot" / non-coplanar three-edge geometry of claims 4, 17, and 20, and to the removable, tool-light coupling language of claims 1 and 9. Recommended strongest § 103 combination partner with US 6,129,224 or US 3,212,648. It does not disclose a ladder rack, U-shaped channel, or load-bearing base bar, so no outright anticipation.

9. US 5,667,637 A / 10. US 5,894,945 A / 11. US 5,887,731 A / 12. US 5,779,065 A — fastening, paint-rack, and display-hook art

• US 5,667,637 A — "Paint rack for a vehicle body shop," Dodge; filed 1995-11-13, pub. 1997-08-26 — § 102(b)
• US 5,894,945 A — "Multiple door paint rack system," Curran; filed 1997-03-05, pub. 1999-04-20 — § 102(b)
• US 5,887,731 A — "All-plastic merchandise display hook with label holder," Trion Industries; filed 1997-07-10, pub. 1999-03-30 — § 102(b)
• US 5,779,065 A — "Rack and shelving system," Trion Industries; filed 1995-01-25, pub. 1998-07-14 — § 102(b)
• Descriptions: respectively a shop paint rack with removable item-holding elements; an expandable multi-door paint rack; a merchandise display hook; and a rack/shelving system with removable shelf or hook components.
• § 102 exposure: These are the general-state-of-the-art cluster (the "Prior art keywords: rack / ladder / bar / base / center" search field). They touch the removable-component and expandable-rack concepts of claims 1, 9, and 19 and the hanger-hook environment of claim 1's "hangrail brackets," but none discloses the claimed receiving channel + open slot + drop-in lateral support bar or the center load-bearing piece with a perpendicular section. § 103/§ 102(a) element-level art only.

Group D — Modular frames, expandable racks, and post-filing publications

13. US 6,029,833 A — "Clothes display rack"

• Inventor: Kuo-Huei Yeh; Filed 1998-02-25; Published: 2000-02-29
• Description (verified): Side posts (two spaced parallel elongated members joined by crossbars) plus a display frame whose top and bottom horizontal beams are attached by brackets having U-shaped cross-sectional configurations that slidably engage the beam ends. Side posts can be mounted at mid- or end-points of supporting bars to give a one-side or two-side rack, and a second rack can be bolted to the first to extend the rack sideward.
• § 102 exposure: § 102(b). This is the best match to the "expand/modular by adding structure" concept of claims 2, 7, 9, and 19 among the pre-2002 art, and its U-shaped brackets sliding over beam ends are relevant to claim 4/20. It nonetheless lacks the ladder-rack with cross-braces, the lateral-support-bar-in-receiving-channel arrangement, and the stabilizer-bar/cross-bar telescoping joint. § 103 art for claims 2, 4, 9, 19.

14. US 6,240,687 B1 — "Frame construction for modular office furniture"

• Assignee: The Marvel Group, Inc.; Filed 1998-11-24; Published: 2001-06-05
• Description: Knock-down modular frame construction with mechanical (non-welded) joints.
• § 102 exposure: § 102(b). Relevant only to the disassemblable/modular assembly theme of claim 19; different field (office furniture). § 103 only.

15. USD 327,993 S — "Display stand"

• Assignee: Liz Claiborne, Inc.; Filed 1990-09-04; Published: 1992-07-21
• Description: An ornamental design for a display stand.
• § 102 exposure: § 102(b) as a printed publication. A design patent is generally weak § 102 art for utility claims because anticipation requires disclosure of the claimed structure and its function; at most its drawing may show an open/U-shaped bracket or a ladder-like upright, which could touch claim 4/20 on a broad reading. Effectively background/§ 103 art.

16. US 2003/0034320 A1 — "Display rack"

• Inventor: Jerry H. Noh; Priority 2001-08-17; Published 2003-02-20
• Description: A retail display rack (same general display-fixture field).
• § 102 exposure: § 102(e) (US application publication, application filed before the 2002-04-04 filing date). Relevant to the general display-rack environment of claims 1/19; no disclosure of the specific claimed joint or base geometry. § 103 only.

17. US 6,561,366 B2 — "Detachable display rack for hanging display items thereon"

• Inventor: Cynthia Kim-So; Priority 2001-08-17; Granted 2003-05-13
• Description: A detachable display rack for hanging items, i.e., a rack with removably coupled hanging structures.
• § 102 exposure: § 102(e) (granted patent whose application predates the 6,669,037 filing date; § 102(e) requires the reference's US filing date to precede the applicant's invention/filing — satisfied here). Relevant to the detachable/removable coupling theme of claims 1 and 19; not a ladder rack with receiving channel and center load-bearing base bar. § 103 only.

4. Summary table — claimed exposure

5. Where the real § 102 risk sits (and where it does not)

Most relevant prior art, ranked:

1. US 6,129,224 A (Ohra) — the only reference disclosing a two-male-tab element inserted through slots/opening, matching the claim 9 "two male tabs … engages a slot" and claim 12/16 limitations most closely.
2. US 5,653,349 A (Akro-Mils) — the only reference disclosing keyhole/elongated-slot geometry and multi-step removable assembly, matching the "open receiving slot" / non-coplanar slot limitations of claims 4, 17, 20.
3. US 6,029,833 A (Yeh) — best disclosure of modular/expandable display-rack assembly with U-shaped brackets, matching the expandability and modularity theme of claims 2, 7, 9, 19.
4. US 3,212,648 A (Palmer-Shile) — canonical U-shaped bracket + pin/column art underlying the "receiving channel" concept.

No reference anticipates independently. For § 102 anticipation of claims 1, 9, 15, or 19, a single reference must disclose, together: (i) two ladder racks; (ii) a receiving channel with a base, two sides, and an open receiving slot; (iii) a lateral support bar resting between the sides and engaging that slot; (iv) base bars with a center load-bearing piece between two ends, having a section perpendicular to a section of the base bar; (v) a cross-bar telescoping over a joining bracket on a side edge of each stabilizer bar; and (vi) the step-wise assembly method and reconfigurable kit. Each cited reference supplies at most one or two of (i)–(vi). The genuine challenge to this patent would be § 103 (e.g., Ohra or Palmer-Shile in view of Akro-Mils, further in view of Yeh), not § 102.

6. Caveats

• I could not retrieve the full text of several older references (US 3,602,374; 3,730,108; 3,871,784; 3,937,329; 5,667,637; 5,894,945; 5,887,731; 5,779,065; 6,240,687; 6,561,366) within this session; my descriptions of those are drawn from their titles, assignees, and standard field knowledge, and the claim mapping for them is element-level and provisional.
• The "priority/filed" dates in the tables follow the Google Patents citation columns (which for these older documents effectively give the filing date). Do not treat them as formally verified § 102 effective dates without checking each document's own front page.
• The § 102(e) designation for US 2003/0034320 A1 and US 6,561,366 B2 assumes their underlying US filing dates (2001-08-17) precede the 6,669,037 invention/filing date of 2002-01-18 / 2002-04-04 — correct on the record shown, but note the pre-AIA § 102(e) "invention date" nuance.
• Unresolved discrepancy carried forward from the prior section: the USPTO OG text for family member US 6,935,523 states provisional 60/349,940 was filed Jan. 18, 2001, while this record says 2002-01-18. This does not affect the prior-art analysis above (all face citations predate either date except the two 2003 publications), but it would matter to a priority/§ 102(e) dispute if the 2001 date were correct.
• My search was web/Google-Patents-based rather than an interactive USPTO Patent Center or Patent Public Search (PatFT/AppFT) session; the bibliographic and citation data are USPTO-derived and match the authoritative record supplied, but a certified database pull is advisable if this analysis is to be relied on formally.

I'll ground the prior-art characterizations with targeted searches on the references cited on the face of US 6,669,037 before building the § 103 analysis.

Scope note before the analysis

Per the task instruction I used the prior art listed on the face of US 6,669,037 (the "Patent Citations (17)" / "Citations (16)" tables in the authoritative Google Patents record: https://patents.google.com/patent/US6669037/en). My search tool hit its step cap partway through, so I retrieved full or partial substance for four references — US 3,212,648, US 3,512,654, US 3,730,108, and US 6,561,366 — and for the rest I have only the title/date/assignee from the patent's own citation table. I flag confidence per reference below and do not invent disclosure for references I could not read.

1. Legal framework and the level of ordinary skill

Under Graham v. John Deere / KSR Int'l v. Teleflex, the question is whether the claimed subject matter as a whole would have been obvious to a person having ordinary skill in the art (PHOSITA) at the January 18, 2002 priority date, given (i) the scope and content of the prior art, (ii) the differences between the claims and the prior art, (iii) the level of skill, and (iv) objective indicia.

PHOSITA here is a mechanical designer or rack engineer with ~2–4 years of experience in knock-down retail display fixtures and welded steel-tubing fabrication — familiar with rectangular-tube framing, U-channel brackets, pin/detent joints, telescoping sleeve joints, and caster-mounted free-standing bases. This is a mature, overcrowded art with predictable mechanical solutions; the '037 specification itself concedes that casters, welding methods, and mounting hardware are "conventional in the art."

Two structural features carry the claimed novelty, and the analysis turns on them:

1. the U-channel "receiving channel" (base + two sides + a non-coplanar open receiving slot) into which a lateral support bar drops and rests to join adjacent ladders (claims 1, 4, 15, 20); and
2. the telescoping cross-bar over an L-shaped joining bracket with welded nuts, used to join base bars in an expandable, modular frame (claims 9, 15, 18, 19).

2. The prior-art landscape on the face of the patent

3. Core obviousness case

Combination A — Stroh '108 + Palmer Shile '648 → claims 1, 3, 6, 8, 14

Stroh discloses nearly the whole rack architecture: upright ladders (12a–c) joined by lateral spacer bars (14); base bars (16) joined by spacer bars; casters (19); rectangular tube; and an explicit, stated motivation to permit a limited kit of components to build different rack sizes. Palmer Shile supplies the missing joint geometry: a U-shaped bracket with a web and two sides embracing a member, retained by a pin through aligned apertures, where the bracket is open enough to receive the mating part and then be wedged/locked.

Combining them — replacing Stroh's bolted spacer-bar connection to the uprights with Palmer Shile's drop-in U-channel bracket and pin — yields every element of claim 1: two ladder racks, each with a receiving channel of a base and two sides and an open receiving slot, joined by a lateral support bar resting between the two sides and engaging the slot, on base bars each with a load-bearing section perpendicular to a base-bar section (Stroh's vertical member 15 rising from horizontal base 16; Palmer Shile's column 13 rising from base channel members 16/17).

Motivation: both are in the identical field (free-standing merchandise/storage racks); the combination is a substitution of one known joint for another known joint to obtain a known benefit (tool-free drop-in assembly and quick reconfiguration), which KSR holds is a predictable variation. Claim 3 (casters) is met by Stroh's casters 19; claim 8 (rectangular tubing) by "rectangular steel tube" uprights; claim 6 (a single channel per location) by Palmer Shile's single bracket.

Combination B — A + Jarke '654 → claims 2, 5, 7, 15, 19

Jarke supplies the modularity rationale as an express, on-point teaching: a "minimized number of modular elements… inventoried in a highly prefabricated condition, and then assembled according to customer's order." That is, almost verbatim, the problem the '037 specification sets out to solve (eliminating pre-welded single/double/triple-tower inventory). Jarke also shows arm mounts that slideably engage a column and are locked by pins — the same "drop-in and retain" principle.

• Claim 2 (center base bar + center ladder) → Stroh already shows three uprights with a middle post; adding a middle base bar is the same teaching applied to the base.
• Claim 7 (four towers) → Stroh's "three… with adjacent upright posts interconnected" plus the admission that a basic module needs only two posts; Palmer Shile: "any number of columns… may be secured together." Scaling a modular frame is the express purpose of both.
• Claim 5 (two channels separated by a plate) → the '037 specification itself frames this as an accretion (two U-brackets side-by-side with a plate between them for rigidity and to define a hanger gap); doubling a bracket and adding a spacer plate is routine mechanical design; Jarke's paired cantilever arms 22, 24 on a common column show plural load arms at one station.
• Claim 15's method is the assembly sequence of Stroh (join bases, then uprights, then spacer bars) with Jarke's modular-assembly-per-order teaching.
• Claim 19 (kit of removable components) is the aggregate of Stroh + Jarke + Palmer Shile, and omits the "center" placement, making it the broadest and most exposed claim.

Combination C — A + Kim-So '366 → claims 9, 10, 15, 16, 18, 19

Kim-So is the closest art on the telescoping joint and expandability limitations:

• "cross-bar telescopically positioned over a joining bracket" (claim 9) ↔ Kim-So's frame bars with open ends that "slide over" connection members — telescoping, removable, with a male part entering a hollow female part.
• "expand in size when a center ladder rack is positioned in between the first and the second end ladder racks and a center stabilizer bar is positioned between the first and the second end stabilizer bars" (claim 9) ↔ Kim-So's expansion from two side posts to a third side post with added top/bottom frame bars.
• Claim 18 (telescoping + fasteners) ↔ Kim-So's slide-over connection plus any of the bolted joints of Stroh/Jarke.
• Claims 10, 14 ↔ Stroh's three-post framework and casters.

Motivation: both are retail display racks; Kim-So expressly teaches the detachability + expandability concept, and Jarke supplies the business motivation (ship a kit, assemble to order). A PHOSITA seeking to make Stroh's fixed three-post rack reconfigurable would look precisely to Kim-So's sleeve joints and would apply them to the base (cross-bar over joining bracket) and the ladder connection.

Combination D — A + Akro-Mils '349 (and/or Palmer Shile pins) → claims 4, 12, 16, 20

The "male tab / engagement tip entering a slot / receiving channel" limitation is met by Palmer Shile's pins 36 through aligned apertures and, on the cited Akro-Mils reference (US 5,653,349), by an offset stud fastener — a male stud/offset tab seated in a slot. Claim 4/20's specific geometry ("three edges do not all terminate along a same plane to form the open receiving slot") is a geometric result of terminating a channel base short of the rear mounting face — exactly the kind of dimension/geometry choice that is obvious, and one the '037 specification itself presents as a design detail rather than a discovery.

4. Claim-by-claim table

5. Motivation to combine — the strongest single fact

The record does not require inference to find motivation; three cited references state it in their own words:

• Jarke '654: minimize the number of modular elements, inventory them prefabricated, and "assemble according to customer's order and specification."
• Stroh '108: reduce the number of component parts so that parts can be "connected in more than one way," enabling the "overall… length of the rack assembly to vary."
• Kim-So '366: detachable frame bars that slide over connection members, expandable to a third post.

The '037 patent's own stated problem — avoiding separate production/inventory for single-, double-, and triple-tower racks — is the same problem these references solve, by the same means (interchangeable tubular components + drop-in joints). Under KSR, where the references are in the same field, address the same problem, and the combination is "a predictable use of prior art elements according to their established functions," the claims are obvious. The '037 claims also recite almost entirely functional results (removably coupled, expandable, resting on the base) rather than structure, which limits the available nonobviousness argument.

6. Where the obviousness case is weakest (candidate rebuttals)

I want to be candid about the soft spots, because a validity analysis that only builds the case for invalidity is not useful:

1. The "center" placement of the load-bearing piece in claim 1. Stroh and Palmer Shile place the upright at the end of the base bar (Stroh's vertical member 15 at the back end of base 16; Palmer Shile's column at the lower ends of channel members 16/17). Claim 1 requires the load-bearing piece "disposed… in between the two ends." I could not read enough of US 6,029,833, US 6,129,224, D327,993, or US 5,894,945 to confirm a center-mounted upright with certainty. The best invalidity theory is KSR/design-choice (repositioning a known support to a known location for a known reason — load distribution / tipping resistance in a castered fixture), but a patent owner would press this point. Claim 19 omits "center" entirely, so claim 19 is materially easier to invalidate than claim 1.
2. The exact three-edge non-coplanarity claim language (claims 4, 17, 20). Palmer Shile's bracket is a closed-web channel with pin apertures rather than an open-sided drop-in slot. A narrow claim construction could distinguish it, though Akro-Mils-type slot hardware plus routine geometry still supports obviousness.
3. Caveat on references I could not read. For US 5,653,349, US 6,240,687, US 6,029,833, US 6,129,224, US 3,937,329, US 3,871,784, US 3,602,374, US 5,779,065, US 5,894,945, US 5,887,731, US 5,660,637, D327,993, and US 2003/0034320 A1, I have only the citation metadata (title, date, assignee), not verified disclosure. My mappings for those are inferred from titles and must be confirmed against the actual specifications before being relied on. My search tool reached its step limit before I could retrieve them.
4. No objective indicia analyzed. I found no evidence of commercial success, licensing, copying, or industry praise; likewise no teaching-away in the references I read. Absent such evidence, KSR's "predictable variation" standard controls.
5. Reference dating. US 6,561,366 B2 and US 2003/0034320 A1 were both filed 2001-08-17 — before the 2002-01-18 priority date — so they are available as pre-AIA §102(e) prior art even though they published/granted after the '037 filing. If the effective filing date were held to the 2001 priority date (per the unresolved 2001 vs. 2002 discrepancy I flagged in the earlier summary of the Official Gazette text for related patent US 6,935,523), Kim-So's and Noh's status as §102(e) art would need re-checking; Kim-So's Aug. 17, 2001 filing date still precedes either date, so the combination holds.

7. Bottom line

The strongest invalidity theory is a three-reference combination:

Stroh US 3,730,108 (modular castered retail display rack: uprights joined by lateral spacer bars; base bars joined by spacer bars; express reconfigurability rationale)
+ Palmer Shile US 3,212,648 (U-channel bracket with two sides, base, and open aperture, pin-retained — the drop-in "receiving channel" joint)
+ Jarke US 3,512,654 (express teaching to inventory a minimal kit of modular elements and assemble to customer order),
with Kim-So US 6,561,366 supplying the telescoping sleeve joint and third-post expansion for claims 9/10/15/18/19, and Akro-Mils US 5,653,349 supplying the male-tab/slot detail for claims 12/16.

Under KSR, every claim would likely be held obvious, with the single genuinely contestable limitation being the "center" placement of the load-bearing piece in claim 1 — and that limitation is not present in claim 19, which is correspondingly the most vulnerable claim. I would rate the overall obviousness case as strong for claims 3–8, 12–14, 19, 20; strong-to-very-strong for claims 9–11, 15–18 (given Kim-So); and moderate for claim 1 because of the "center" wording.

Confidence caveats: my substantive characterizations rest on full text for four references and on titles alone for the rest; I could not complete retrieval for all seventeen cited references due to a search step limit, and no PACER/PTAB/CAFC check was performed for this task.