US 3849801

I'll verify this patent against live sources before summarizing.

US 3,849,801 — Verification and Summary

Search results used: Google Patents (https://patents.google.com/patent/US3849801/en), FreePatentsOnline, Justia Patents, and a DTIC bibliography citing the patent. All sources consistent with the full text provided.

CAFC / litigation check — negative result

I found no CAFC 2026 docket, and no litigation activity of any kind, involving US 3,849,801. Search results returned only patent-document and citation records.

• Caveat: I am relying on general web search, not a direct query of the CAFC docket system or PACER. If you need a definitive negative, that must be run against the court's own docket.
• Number-collision warning: results also surfaced EP 3,849,801 A1 ("Polymeric membrane useful as a commercial roofing membrane") and a PTAB petition referring to an unrelated " '980 patent" in the protein-degrader field. These are different instruments that happen to share a similar digit string. They are not US 3,849,801 and should not be conflated.
• Practical note: the record shows "Expired - Lifetime," with anticipated expiration 1991-11-26. The patent has been expired for roughly 34 years, so it is not a live assertion candidate.

Bibliographic data

Assignments of record: Citicorp Industrial Credit (security interest, 1983) → Riddell, Inc. (assignment from Medalist, 1985) → release by secured party (1985) → EN&T Associates, Inc. (1988) → Riddell, Inc. / R Holdings Corp. (change-of-name records, effective 1988-04-22) → National Bank of Detroit (security interest, 1988).

Abstract (verbatim)

"Protective gear such as head gear for use in sports, industry, and the military, etc. includes a one-piece molded protective outer shell such as a helmet shell with a hydraulic energy absorbing liner which has an array of interconnected compressible vinyl walled compartments arranged around a central crown compartment with shock and energy dissipating fluid in the interconnected compartments. Each of the compartments is provided with a porous insert or surge mitigator of open-celled foam, which throttles fluid flow within the compartments as the compartments are compressed and deformed upon impact, thus to absorb or dissipate energy. The porous inserts also prevent sloshing of fluid and retain some fluid in the compartments at all times, preventing complete collapse of one or more compartments during impact. In preferred embodiments, the fluid includes hydraulic liquid."

Plain-language claim overview

Claim 1 — Independent (broadest; general "protective gear")
The base combination: (a) an outer shell; (b) a hydraulic liner with an array of interconnected, collapsible, fluid-containing compartments; (c) hydraulic fluid in them; (d) the interconnections let fluid displaced from a crushed compartment move into other compartments; and (e) — the point of novelty — a deformable, highly porous "surge mitigating means" with substantial void space inside the compartments that (i) throttles fluid flow within and between compartments when impact deforms them, (ii) dissipates/absorbs the impact energy, and (iii) retains fluid in the deformed compartment even though some fluid has been displaced elsewhere. Element (e) is the inventive core.

Claim 10 — Independent (head gear; broader functional framing)
Head gear with an outer covering; an energy-absorbing liner made of discrete fluid compartments; hydraulic fluid; passages joining adjacent compartments so fluid displaced from a deformed one moves to the others; and a deformable, highly porous structure with substantial void space occupying the major portion of the volume of each compartment. That structure supplies controlled resistance to fluid movement within and between compartments and retains fluid during use despite substantial deformation. Note the recitation of "major portion" volume occupancy and the functional "controlled resistance" language.

Claim 13 — Independent (head gear; most structurally specific of the three)
An outer shell shaped to receive a wearer's head; a liner of interconnected deformable compartments with hydraulic fluid and inter-compartment displacement; and a deformable, highly porous, resilient surge-mitigating means with substantial void space that materially fills the compartments. That means supplies a multiplicity of orifices and flow obstructions producing energy-dissipating pressure losses as fluid is forced through and around them during deformation, and it retains fluid in the deformed compartment. This claim most expressly captures the "reticulated open-celled foam" throttling mechanism.

Dependent claims of note

• 2 — limits the means to reticulated inserts creating passages/obstructions causing a pressure drop.
• 3–4 — narrow to open-celled foam, and specifically polyurethane resin.
• 5 — recites the specific architecture: forward, rear and side compartment arrays around a crown compartment, with passages joining each array to the crown.
• 6–7 — air is also present; hydraulic fluid occupies in excess of one-half the total available space.
• 8 — the surge mitigator substantially occupies the compartment volume.
• 9 — adds an intermediate sizing liner between hydraulic liner and shell.
• 11–12 — air plus the less-than-half air / more-than-half fluid volume relationship.
• 14 (dep. 10) and 15 (dep. 13) — add cross-head migration: fluid displaced from a deformed compartment on one side of the head travels through the passages to a compartment on the other side.

Technical substance worth flagging

• Summary of invention / background: the stated problems with prior art hydraulic liners were (i) bottoming-out or complete evacuation of a compartment, causing loss of energy-absorbing capability and consequent injury risk; (ii) sloshing noise; (iii) gravity-driven unequal fluid distribution; and (iv) excess weight from fully filling cells with liquid. Background cites Simpson U.S. 3,039,109, Cade et al. U.S. 3,600,714, and Morgan U.S. 3,609,764.
• Cited prior art of record (8 refs): US 1,795,304 (Sorbo Rubber Sponge); US 3,090,045 (Hurst); US 3,171,820 (Scott Paper — reticulated polyurethane foams); US 3,254,883 (John T. Riddell); US 3,600,726 (Williams); US 3,609,764 (Riddell); US 3,611,455 (Jobst); US 3,668,704 (Conroy).
  • Discrepancy to note: the background section names Simpson 3,039,109 and Cade 3,600,714, but neither appears in the "References Cited" list; only 3,609,764 does. The Google Patents citation list and the printed front page both show the 8 references above.
• Preferred materials: reticulated open-celled polyurethane foam per Volz U.S. 3,171,820 (Scott Industrial Foam); ~0.2 lb./cu. ft. density; 3% skeletal structure / 97% void; 80 pores per linear inch found to give desired regulated flow.
• Working example figures (16 fl. oz. fill): hydraulic fluid ≈65%, air ≈30%, foam solids ≈5%. Measured volumes: total cell envelope 724.4 mL; hydraulic fluid 473.16 mL; air 216.4 mL; foam insert (excluding void) 34.84 mL. Fluid is 8 oz water + 8 oz propylene glycol (miscible, low freezing point).
• Claim drafting observation: the independent claims use "highly porous means" / "surge mitigating means" language — a classic §112 ¶6-type means-plus-function formulation. Claim 1 also includes what appears to be an OCR artifact in the source text ("outer shall" for "outer shell"); the corrected reading is "shell."

Uncertainty disclosure

The bibliographic data, abstract, claim text, and specification details above are authoritative, taken from the full patent text supplied and corroborated by Google Patents/FreePatentsOnline/Justia. The litigation/docket-check items are the weak link — I have no authoritative confirmation of CAFC or district court activity, and my negative finding rests on general web search rather than direct docket access. A prior-art-search-style answer should not be given on this record without a direct PTAB/PACER/CAFC query.

I'll search for litigation involving US patent 3849801.

Let me run additional targeted searches to be thorough.

Let me make a couple more targeted attempts before concluding.

Bottom line

I found no record of any litigation — patent infringement or otherwise — involving U.S. Patent No. 3,849,801. Based on the searches I was able to run, there is no known case in which US 3,849,801 was asserted as a patent-in-suit, challenged in a PTAB/IPR/reexam proceeding, or otherwise appeared as the subject patent in a court docket.

I want to be explicit that this is a negative finding with meaningful caveats (detailed at the end), not an affirmative confirmation that no case ever existed.

1. What I searched, and what came back

I ran multiple queries against open web/patent sources (Google Patents family data, Justia Patents, CourtListener/CAFC opinion PDFs, and general litigation-portal style results):

Notably, the patent does appear in the academic/technical literature — e.g., a DTIC report cites it as Holt, M. C., and Tomczak, W. F., "Protective Gear with Hydraulic Liner", US Patent 3849801, 1974 (DTIC ADA520090) — and it is cited as prior art by later helmet patents (e.g., US 12,256,797, "Soft shell helmet"). Citation as prior art is not litigation.

2. Important false positives — do not conflate

My searches surfaced several cases involving a "'980 patent" that are NOT US 3,849,801. I flag these because an automated keyword match on "980" is easy to misread:

• Deere & Co. v. Duroc LLC (fka Bush Hog), Alamo Group, Bush Hog, Inc., and Great Plains Mfg. — S.D. Iowa, No. 3:09-cv-00095-CRW; Fed. Cir. appeal No. 14-1403. This concerns U.S. Patent No. 6,052,980, a rotary-cutter patent, not a helmet patent. (See CAFC 14-1403 record.)
• Nearby Systems v. [Defendants] — E.D. Tex., No. 2:25-cv-00015, asserting U.S. Patent No. 11,937,145 (mapping systems). The complaint's repeated references to "the '980 patent" refer to a different patent in that portfolio, not US 3,849,801.

Similarly, Riddell's well-known helmet litigation asserts other Riddell patents, never the '801:

• Riddell, Inc. v. Schutt Sports, Inc. — W.D. Wis., No. 08-cv-711 (asserting U.S. Patents 6,934,971; 7,240,376; 7,036,151) (case summary)
• Riddell, Inc. v. Kranos Corp. / Kranos IP Corp. — N.D. Ill., No. 1:16-cv-04496 (asserting U.S. Patents 8,938,818; 8,813,269; and others), with related IPRs (e.g., IPR2016-01649, IPR2016-01650)
• Riddell, Inc. v. Certor / Schutt / VICIS — D. Del. (asserting U.S. Patent 10,506,841)

The closest thing to a "3,849,801 litigation" connection I found is a product-liability / design-defect complaint (Jones v. BRG Sports, via CCH) that quotes a Riddell spokeswoman saying "Riddell patented throttled-air technology in the 1970s and tried, used and discontinued using it." That is a reference to the hydraulic/throttled-fluid technology era of this patent family, but it is a tort suit about helmet design, not a patent infringement action asserting US 3,849,801.

3. Why the absence of litigation is plausible

This is not a surprising null result:

• The patent expired long ago. Per the Google Patents record, US 3,849,801 issued November 26, 1974, was filed December 20, 1972 (App. No. 316,799), and its anticipated expiration date is listed as November 26, 1991, with legal status "Expired – Lifetime." Any infringement action would have had to be filed on or before that date (subject to the then-applicable six-year § 286 damages lookback).
• Pre-1991 litigation is poorly digitized. Free sources (Google Patents, Justia, CourtListener, Unified Patents) have sparse coverage of 1970s–1980s district court dockets. CourtListener's RECAP only collects documents users upload, and PACER's full-text search is not freely accessible. A 1975–1990 infringement suit over the '801 could exist in paper or PACER-only form without appearing in these searches.
• Ownership history shows no assertion. The chain — Medalist Industries (original assignee) → Riddell, Inc. (1985 assignment) → EN&T Associates (1988) → R HOLDINGS CORP. (1988 name change) — is documented in the assignment records on the Google Patents page. Riddell became a frequent patent plaintiff, but only decades later and on later patents.

4. Confidence and limitations — read this before relying on the answer

• Confidence: moderate-to-high that no litigation is documented in public free databases; moderate overall. I am confident about the modern era (post-~2000). I am not in a position to rule out a 1970s/1980s suit that never made it into digitized records.
• I do not know with high confidence whether any litigation exists that is not indexed by the sources above. I did not obtain a definitive case list from the Unified Patents litigation portal for this specific number — my query returned no matching portal entry, which is consistent with (but not proof of) zero litigation.
• Limitation of method: all conclusions above rest on keyword searches; a patent that has been litigated rarely (or only in state court, or only in foreign jurisdictions) may not surface.

Recommended next steps if you need a definitive answer

1. USPTO Patent Assignment / litigation-history search and the USPTO Patent Litigation Docket (or Docket Navigator / Lex Machina / Westlaw Litigation Analytics), which have deeper historical coverage than free tools.
2. PACER Case Locator search on "3,849,801" and on assignees Medalist Industries, Inc., Riddell, Inc., and EN&T Associates, Inc. for the 1975–1991 window.
3. Federal Circuit / regional circuit (7th Cir.) historical opinions for 1975–1991, since the Federal Circuit did not exist until 1982.
4. A professional prior-art/litigation search (e.g., a full-text search of the U.S. Patents Quarterly and BNA databases), which indexes many older decisions not available online.

If you need a formal opinion, I would report: "No litigation involving U.S. Patent No. 3,849,801 is known or identified in publicly available sources as of April 26, 2026," subject to the search-scope limitations above.

I'll verify the canonical "no proceedings" signal against public sources before writing.

Let me run two final checks — PTAB E2E-style docket mentions and any defensive-aggregator or litigation activity.

Proceedings overview

Total AIA trial proceedings on US 3,849,801: 0 (zero). The USPTO Open Data Portal returns no IPR, PGR, or CBM proceedings for this patent, and independent web searching surfaced none — break down of status is therefore 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denied. The defensive posture this gives a defendant is the strongest possible, but not for the reason the usual framing assumes: this is not a "hardened, IPR-surviving" patent. US 3,849,801 (Holt & Tomczak, "Protective Gear with Hydraulic Liner," assignee Medalist Industries, Inc.) issued 1974-11-26 and its legal status on the face of the record is "Expired – Lifetime," with an anticipated expiration of 1991-11-26 (Google Patents, US3849801A). Any demand letter citing claims 1–15 of this patent is asserting a patent that has been dead for roughly 35 years. That is a Rule 11 / § 285 problem for the sender, not a licensing opportunity for you.

No proceedings on file

There are no IPR, PGR, or CBM case numbers to report. I will not manufacture proceeding numbers, panels, or Final Written Decisions that do not exist. For completeness, here is what I did find when checking the patent owner's neighborhood — none of it touches the '801 patent:

• Kranos Corporation d/b/a Schutt Sports v. Riddell, Inc., IPR2016-01646 (U.S. Pat. No. 8,528,118 B2), IPR2016-01650 (U.S. Pat. No. 8,938,818 B2), and IPR2016-01649 (U.S. Pat. No. 8,813,269) — these are Riddell helmet patents, but they are 2000s-era patents, not the 1974 '801 patent. FWDs issued in February 2018, with extensive remand activity after SAS Institute Inc. v. Iancu (see Petitioner's Supplemental Brief, IPR2016-01646/-01650 and Patent Owner's Motion to Exclude).
• Inter partes reexamination Control No. 95/002,117 — a Riddell-related reexam, again not directed to the '801 patent.
• Riddell, Inc. v. Schutt Sports, Inc., No. 08-cv-711 (W.D. Wis.) and Riddell, Inc. v. Kranos Corp., No. 1:16-cv-04496 (N.D. Ill.) — the Riddell helmet wars litigated the Revolution-era patents, not the '801 hydraulic-liner patent.

The '801 patent appears in the public record essentially only as prior art and background literature — e.g., it is cited in later helmet patents (US 12,256,797; US 10,271,605; US 10,161,193) and in a 2010s DTIC/Army research report on helmet padding. That is the profile of a long-expired technical reference, not a patent under attack.

Strategic summary

Claim status: all claims 1–15 are UNTESTED at the PTAB — and moot. No claim of US 3,849,801 has ever been canceled in an AIA trial, because no AIA trial has ever been filed. But "untested" here is not "presumed good." Claim 1 (protective gear with an outer shell, a hydraulic liner with interconnected collapsible fluid compartments, and deformable highly porous surge-mitigating means), claim 10, and claim 13 are all recited against a 1972-12-20 priority date and a patent term that ended 1991-11-26. There is no live claim to invalidate, license, or assert.

Why there is no PTAB activity — and why the absence carries no "hardening" signal. In the ordinary case, the prompt's heuristic is right: a well-asserted patent attracts IPRs, and a clean PTAB record is itself informative. That heuristic does not apply here. (i) PGR is statutorily unavailable: 35 U.S.C. § 321(c) limits post-grant review to patents subject to first-inventor-to-file, i.e., effective filing dates on or after 2013-03-16; this patent's date is 1972-12-20. (ii) CBM is unavailable: the AIA § 18 transitional program covered only "covered business method" patents for financial products or services, a category this helmet-liner patent was never in, and the program sunset on 2020-09-16. (iii) IPR is technically available for any patent under 35 U.S.C. § 311 — the Board has instituted IPRs on expired patents — but there is no rational petitioner: § 315(b)'s one-year clock runs from service of a complaint alleging infringement, and no such complaint can be validly served on an expired patent; the AIA trial bar and defensive aggregators (Unified Patents and the like) do not file on 1974 patents. The absence of PTAB activity is therefore not evidence the claims are strong — it is evidence the patent is inert.

Estoppel landscape — § 315(e)(2) is a non-issue. Because no petitioner has ever been party to an IPR on this patent, there is no IPR estoppel barring anyone. Every prior-art ground is theoretically "available" — but unenforceably so, because validity in district court is irrelevant when the patent has expired. Likewise, the pre-AIA prior art cited on the face of the patent — US 1,795,304 (Sorbo Rubber Sponge), US 3,090,045 (Hurst), US 3,171,820 (Scott Paper, reticulated polyurethane foams — the reference the specification itself relies on for its preferred foam), US 3,254,883 (John T. Riddell), US 3,600,726 (Williams), US 3,609,764 (Riddell), US 3,611,455 (Jobst), and US 3,668,704 (Conroy) — remains a clean and powerful § 102/§ 103 record if validity were ever somehow in play.

Pattern signals. Patent owner Medalist Industries, Inc. never pursued PTAB proceedings — it could not; the PTAB did not exist in usable form until 2012, and by then the chain of title had long since passed to Riddell, Inc., EN&T Associates, Inc. (c/o The Nederlander Organization), and R HOLDINGS CORP (change of name, effective 1988-04-22), with security interests recorded to Citicorp Industrial Credit and National Bank of Detroit. No defensive aggregator appears anywhere in the chain. The Riddell-side IPRs at IPR2016-01646/-01649/-01650 and the SAS remands show Riddell was an active patent owner litigating AIA trials on its modern portfolio — but purely as a Patent Owner, and never on this patent.

Recommended next steps

1. If a demand letter or complaint cites US 3,849,801, treat it as a bad-faith assertion. Lead with the record: legal status "Expired – Lifetime," anticipated expiration 1991-11-26 (Google Patents). A patent that expired in 1991 cannot be infringed, cannot support an injunction, and cannot support damages — and 35 U.S.C. § 286's six-year look-back, measured from 1991, captures nothing. Preserve the demand letter and consider a § 285 / Rule 11 posture.
2. Do not spend money on an IPR on this patent. There is nothing to invalidate and no live claim to defend against. Filing would be a waste of fees and would create no useful estoppel, because no one else is constrained either.
3. There are no trial-stage milestones to track — no institution decision deadline, no oral hearing, no § 318(a) FWD due date, because no trial exists. Re-confirm periodically against USPTO Patent Trial and Appeal Board E2E and CourtListener if you want to memorialize diligence, but I expect the record to stay empty: this patent is a 1974 citation, not an assertion vehicle.
4. Watch the real targets instead. If you are in the football-helmet space, the patents actually being litigated and IPR'd by and against Riddell are the 2000s-era ones — US 8,528,118, US 8,938,818, US 8,813,269, US 10,161,193, US 10,271,605 — as shown by the Kranos/Schutt IPR2016-01646/-01649/-01650 family and Reexam 95/002,117. Those, not the '801, are where a helmet defendant's invalidity and estoppel strategy belongs.

Confidence and caveats. I have high confidence there are no AIA trial proceedings on US 3,849,801: the ODP structured block returns none, and no public source surfaced a single IPR/PGR/CBM number, FWD, institution decision, or Federal Circuit appeal naming this patent — including searches of PTAB-hosted document repositories and CourtListener. I did not locate any litigation in which the '801 patent was itself asserted; the Riddell/Schutt and Riddell/Kranos dockets I reviewed concerned other patents. Because I cannot see a sealed or very recently filed docket, treat this as "no PTAB activity on file" rather than an absolute negative, and re-verify before filing anything that relies on it.

I'll verify the assignment chain against live sources before reconstructing it.

Ownership Chain — US 3,849,801 (Protective gear with hydraulic liner)

Source note / verification path. The assignment facts below are taken from the legal-event table of the patent record itself (Google Patents, https://patents.google.com/patent/US3849801/en), which mirrors the USPTO assignment database and shows reel/frame for each recording. I attempted to corroborate against USPTO Assignment Center and assignment.uspto.gov (search 3849801), and against SEC filings for the public-company portion of the chain.

Gap I must flag up front: the correspondent-of-record field was not retrievable through the sources I could reach. Google Patents' legal-event table omits correspondent, and my retrieval of the Assignment Center record did not surface it. I will therefore list the correspondent as not verified for every entry rather than guess. The reel/frame citations below are the exact numbers of record and can be used for direct manual lookup. (Note also that the attorney of record at issuance — Joseph P. House, Jr. — is the prosecuting attorney on the printed front page, not a recording correspondent; do not conflate the two.)

Also carrying forward the number-collision warning from the prior section: EP 3,849,801 A1 (roofing membrane) and the protein-degrader " '980 patent" are unrelated instruments and do not appear in this assignment record.

Inventors

• Both named inventors reside in Leesburg, Florida, while the assignee of record is Medalist Industries, Inc., Milwaukee, Wis. The common out-of-state residence of both inventors indicates a single Medalist facility in Leesburg rather than two independent inventors — a common and unremarkable pattern for a corporate R&D site.
• Pattern check requested (inventor departure within 12 months of filing): not determinable. The record contains no information about inventor employment after filing, no separate inventor-to-company assignments, and no later patents by these inventors surfaced in my search. I cannot confirm or deny a departure pattern, and I decline to infer one. The patent is also cited in a DTIC bibliography (Holt & Tomczak, US 3,849,801, 1974), indicating downstream use of the disclosure in military helmet research — that is a citation fact, not an ownership fact.

Original assignee

Medalist Industries, Inc., Milwaukee, Wisconsin (original assignee as printed; Ser. No. 316,799).

• Line of business: diversified sporting-goods manufacturer; the Riddell helmet/team-equipment business was a Medalist unit at the time of filing.
• Product embodying the claims: yes — the specification describes the invention as embodied in a football helmet (shell 12, sizing liner 16, hydraulic suspension 50 with surge mitigators 89), i.e., an actual production article rather than a paper design. Whether the specific 16-compartment hydraulic suspension of FIG. 2 was ever a catalog item is not confirmed by anything I found.
• Current status: dissolved/absorbed. Medalist divested the Riddell business to Riddell, Inc. by September 1982 (see reel 004381/0239), and the corporate name does not survive as an operating entity. I found no verified record of a Medalist bankruptcy filing; the 1982 divestiture plus an immediate secured financing is consistent with a leveraged sale of a division, but the bankruptcy characterization is unverified and I am not asserting it.

Assignment timeline

All seven recordings below are the complete set of assignment events of record for this patent.

• 1982-09-30 (executed) / recorded 1985-04-08 — Reel 004381/0239

  • Conveyance: Assignment
  • Assignor: Medalist Industries, Inc.
  • Assignee: Riddell, Inc. (1125 Tower Lane, Bensenville, Illinois)
  • Correspondent: not verified (field not retrievable from available sources)
  • Context: division divestiture — Medalist sold the Riddell business; note the ~2.5-year lag between execution and recording, which is why this entry appears out of sequence.

• 1982-10-12 (executed) / recorded 1983-03-25 — Reel 004110/0984

  • Conveyance: Security Interest (Security Agreement)
  • Assignor: Riddell, Inc.
  • Assignee: Citicorp Industrial Credit, Inc. (200 South Wacker Drive, Chicago)
  • Correspondent: not verified
  • Context: securitization — collateral grant on the newly acquired Riddell assets; not a transfer of title. Its 1982-10-12 effective date is what dates the Medalist→Riddell closing to September/October 1982.

• 1985-03-13 (executed) / recorded 1985-05-20 — Reel 004402/0703

  • Conveyance: Release (Released by Secured Party)
  • Assignor: Citicorp Industrial Credit, Inc.
  • Assignee: Riddell, Inc.
  • Correspondent: not verified
  • Context: securitization unwind — extinguishment of the Citicorp lien, title unaffected.

• 1988-04-18 (executed) / recorded 1988-04-27 — Reel 004899/0145

  • Conveyance: Assignment
  • Assignor: Riddell, Inc., an Illinois corporation
  • Assignee: EN&T Associates, Inc., c/o The Nederlander Organization
  • Correspondent: not verified
  • Context: acquisition — the operating-business purchase by the Nederlander-affiliated investment group (Robert E. Nederlander became chairman of the resulting public company, Riddell Sports Inc., in April 1988). This is the single link in the chain whose "c/o" address could superficially read as anonymous shell custody; it is not. The acquirer renamed itself to the acquired brand days later (next entry) and operated the business.

• 1988-04-30 (executed) / recorded 1988-06-13 — Reel 004893/0712

  • Conveyance: Change of Name
  • Assignor: EN&T Associates, Inc.
  • Assignee: Riddell, Inc.
  • Correspondent: not verified
  • Context: change of name only — no transfer of title.

• 1988-04-18 (executed) / recorded 1988-06-13 — Reel 004904/0125

  • Conveyance: Change of Name
  • Assignor: Riddell, Inc.
  • Assignee: R Holdings Corp.
  • Correspondent: not verified
  • Context: change of name only — the pre-1988 Riddell, Inc. (Bensenville, Ill.) was renamed R Holdings Corp., while the buyer took the Riddell name. Reads as an acquisition-stage corporate reorganization, not an asset transfer.

  Chain ambiguity worth recording: the two change-of-name entries carry inverted effective dates relative to their economic logic (old Riddell → R Holdings effective 1988-04-18; EN&T → Riddell effective 1988-04-30), yet both were recorded on the same day, 1988-06-13. This is consistent with a simultaneous close-and-rename, but the reel ordering (004893 before 004904) does not track the effective dates. Anyone relying on the record for a title opinion should read the underlying documents, not the event table.

• 1988-04-25 (executed) / recorded 1988-08-01 — Reel 004925/0664

  • Conveyance: Security Interest (Security Agreement)
  • Assignor: EN&T Associates, Inc.
  • Assignee: National Bank of Detroit (611 Woodward Avenue, Detroit, MI 48226)
  • Correspondent: not verified
  • Context: securitization — acquisition financing lien; recorded by the lender under the pre-rename name of the borrowing entity, one week before the name change.

No assignment events are recorded after 1988-08-01. Title of record therefore still sits with the Riddell, Inc. / R Holdings Corp. family (Google Patents lists both as current assignee). The later public-company succession — Riddell Sports Inc. (public from 1991), the 1997 Varsity Spirit merger, the 2001 sale of the Riddell Sports Division, the 2004 Fenway Partners Riddell Holdings acquisition, and the 2006 Easton-Bell combination — produced no recorded assignment for this patent, which is entirely expected: the patent's anticipated expiration was 1991-11-26, before that era of transactions, and expired patents are rarely recorded further.

Timeline diagram

timeline
    title Ownership of US 3849801
    1972 : Filed by Medalist Industries Inc
    1974 : Patent issued
    1982 : Riddell business sold to Riddell Inc
    1983 : Security interest to Citicorp Industrial Credit
    1985 : Citicorp security interest released
    1988 : Business acquired by EN and T Associates
         : EN and T renamed Riddell Inc
         : Old Riddell renamed R Holdings Corp
         : Security interest to National Bank of Detroit
    1991 : Patent expired

(Note: "EN&T" is rendered as "EN and T" solely to keep the timeline parser safe.)

NPE / troll-pattern signals

Verdict

Defensive / non-asserting — selected as the least-misleading of the five rubric options, with an explicit scope note below.

Justification. The chain is a conventional operating-company ownership history with zero NPE signals: two title transfers only — Medalist → Riddell, Inc. (reel 004381/0239, executed 1982-09-30) and old Riddell → EN&T Associates (reel 004899/0145, executed 1988-04-18) — bracketed by two bank security interests (reels 004110/0984 and 004925/0664) and their release (reel 004402/0703), plus two pure change-of-name records (reels 004893/0712 and 004904/0125). No licensing entity, no known asserter, no cascading LLC transfers, no assertion activity, and the patent expired on 1991-11-26 — roughly 34 years ago.

Flagged contradiction with the task rubric: the rubric defines this verdict as "chain terminates at a defensive aggregator." That is not what happened here — there is no RPX/AST/LOT/Unified/OIN link. Conversely, the rubric's "Insufficient data" option is defined as "no records, or only the original assignment," and that also does not apply, since seven recordings exist. No rubric option cleanly describes an expired 1970s patent whose title stayed inside an operating sporting-goods company and was never asserted. I have chosen this label because its operative consequence — non-asserted, effectively neutralized — is the accurate one. The affirmative finding is: no NPE pattern is present.

Caveat carried forward. The litigation negative and the correspondent field are the two soft spots. Both require a direct manual pull of the Assignment Center record (search 3849801 at https://assignmentcenter.uspto.gov/) and a direct docket query. Everything else above is grounded in specific reel/frame entries that can be independently verified.

I'll verify the patent record and then examine each cited reference.

Now let me pull details on each cited reference.

Prior-Art Analysis — US 3,849,801 ("Protective gear with hydraulic liner")

0. Scope confirmation (literal-number discipline)

The reference examined is US 3,849,801 A (application US00316799A, Ser. No. 316,799). I did not substitute or merge any near-number. Specifically, I excluded:

• EP 3,849,801 A1 (roofing membrane) — different instrument, flagged in the earlier section of this analysis.
• The unrelated "'980 patent" referenced in an unrelated PTAB petition.
• U.S. Class 2/413 listing entries for neighboring numbers.

Document of record used: the USPTO-issued patent PDF (patentimages.storage.googleapis.com/c6/1c/a6/9c92c1a8904c34/US3849801.pdf) and the Google Patents record (https://patents.google.com/patent/US3849801/en), both consistent with the full text supplied. I could not reach USPTO PatentCenter directly in this session; the Google Patents citation tables were used as the transcription of the printed front page, and where the two differ I say so below.

Critical date: filing 1972-12-20, no priority claim ⇒ the pre-AIA §102(b) bar date is 1971-12-20. Seven of the eight references of record were granted before that date and are therefore full statutory bars; only one is §102(a)/(e)-only.

1. The eight references cited of record

Number check: the printed front page renders the Jobst reference as "3,611,455," i.e. digits 3611455 — identical to the normalized "US3611455A" entry. This is not a discrepancy; no correction applied. Likewise "3,600,726" and "3,609,764" match US3600726A and US3609764A.

2. What is not on the list but is in the specification

The Background of the '801 patent names two references that do not appear in "References Cited":

• Simpson, US 3,039,109 — hydraulic-fluid safety helmet liner. Independently confirmed as real and germane: US 3,668,704 (Conroy) cites it for "liquid filled, as well as gas filled, liners." A true §102(b) liquid-liner reference that was not of record.
• Cade et al., US 3,600,714 — also a liquid-liner helmet. Flagged discrepancy: a reference list in a later patent (US 10,932,514) renders 3,600,714 as "Greathouse, 8/1971." I could not verify the inventor/assignee of 3,600,714 with confidence, and the '801 Background's "Cade et al." attribution is therefore unverified.

Also outside the record but highly relevant: US 3,713,640 and US 3,882,547 (Morgan/Riddell, same family as item 6) — the latter claiming liquid chambers with flap valves and resilient padding inside compartments — and a "3,600,713, 8/1971, Holt" entry appearing in the US 3,882,547 reference list per search OCR (Holt being a named '801 inventor). Treat the Holt number as low-confidence, OCR-derived.

3. §102 element-by-element analysis

For anticipation under §102, one reference must disclose every limitation. Judge on the three independents:

• Claim 1: shell + array of interconnected collapsible hydraulic-fluid compartments + hydraulic fluid + inter-compartment displacement + deformable highly porous surge mitigator with substantial void space in the compartments that throttles flow, dissipates energy, and retains fluid in the deformed compartment.
• Claim 10: head gear analogue, with the porous structure occupying the "major portion of the volume" of each compartment and giving "controlled resistance."
• Claim 13: head gear analogue requiring a resilient porous means "materially filling" the compartments and providing "a plurality of fluid orifices and flow obstructions."

Net result: none of the eight cited references is a clean single-reference §102 anticipation of independent claim 1, 10, or 13. Each is missing at least the "highly porous surge mitigating means in the hydraulic compartments" — the acknowledged inventive core. That is consistent with the examiner's citation pattern: these are §103/combination references, plus the material reference.

Where §102 pressure is nonetheless greatest:

• Against claim 1/10/13 preambles and outer structure: Morgan '764 (item 6), read alone, discloses everything except the porous-in-the-hydraulic-cell limitation.
• Against claim 13's "orifices and flow obstructions… pressure losses": two partial routes — Riddell '883's metered port array (item 4) and Jobst '455's liquid-retarding cellular foam (item 7).
• Against claim 10's "major portion of the volume" / fluid retention: Jobst '455's ~80% liquid load in an open-cell foam body is the nearest disclosure, but in a seat cushion, not head gear.
• Against claim 4 ("foam is a polyurethane resin"): Volz/Scott '820 (item 3) is anticipatory of the material, and '801 itself concedes the material is old.
• Claims 5 and 9 (compartment architecture; intermediate sizing liner) have no §102 counterpart in the cited set — the sizing-liner concept in claim 9 maps instead to Morgan '764's sizing means (item 6).
• Claims 6–7 and 11–12 (air present; fluid > one-half of available space) are not anticipated; Jobst '455 (80% liquid) is the nearest §103 showing on the volume ratio.
• Claims 14–15 (cross-head migration) have no §102 counterpart.

4. Ranking — most relevant prior art

1. US 3,609,764 (Morgan; Riddell) — the closest overall and admitted prior art in the '801 Background. Every structural element of '801 minus the surge mitigator. Note the common assignee (Riddell) and inventor overlap with the '801 family.
2. US 3,611,455 (Jobst) — the closest to the actual point of novelty: open-cell foam inside a liquid-filled envelope, retarding liquid flow and retaining liquid.
3. US 3,254,883 (John T. Riddell) — shell + interior resilient member + orifice-metered fluid flow = energy absorption.
4. US 3,668,704 (Conroy) — shell + multi-compartment inflatable liner + foam + inflation valve.
5. US 3,171,820 (Scott Paper / Volz) — the specific reticulated polyurethane foam, expressly named in the '801 specification.
6. US 3,600,726 (Williams) — support/pressure distribution; content unverified.
7. US 3,090,045 (Hurst) — head appliance; peripheral.
8. US 1,795,304 (Sorbo) — sponge cushion; peripheral.

Off-record art that should be run down before any validity opinion: US 3,039,109 (Simpson); US 3,600,714 (Cade et al. / possibly Greathouse); US 3,713,640 and US 3,882,547 (Morgan/Riddell); and the "3,600,713 / Holt" entry.

5. Caveats

• Full text not obtained for US 1,795,304, US 3,090,045, US 3,171,820 and US 3,600,726. My descriptions of those four rest on the citation record and titles; the §102 conclusions for items 2 and 5 are accordingly provisional. The four I quote (3,254,883, 3,609,764, 3,611,455, 3,668,704) are grounded in retrieved specification text.
• USPTO PatentCenter was not queried directly in this session. The patent text used is the official USPTO-issued document, which is authoritative for the claims and citation list; the file-wrapper prosecution history (which would show which reference the examiner actually applied against which claim) was not available and is the correct next step for a definitive §102 record.
• Discrepancy flagged (not resolved): Background names "Cade et al., US 3,600,714," while a later patent's reference list renders 3,600,714 as "Greathouse." I did not auto-correct either.
• No live assertion posture: the patent is Expired – Lifetime (anticipated expiration 1991-11-26), so this analysis is historical/validity-oriented, not a freedom-to-operate or infringement analysis.

I'll ground this obviousness analysis by pulling the actual content of each cited reference before mapping claim elements.

Good grounding so far. Let me pull the remaining cited references.

Obviousness Analysis — US 3,849,801 Under 35 U.S.C. § 103

Building on: the verified bibliographic data, claim overview, and prior-art inventory from the previously generated sections. I do not repeat that material; I use it as the foundation. One cross-reference note is handled in §7 below.

Method note: I fetched and read the cited references that were retrievable before exhausting my search budget (Cade '714, Scott/Volz '820, Jobst '455, Conroy '704). For the remaining cited references, I rely on (a) the descriptions given in the '801 specification and (b) the Google Patents "Patent Citations" records reproduced in the provided full text. I flag where that reliance is second-hand.

1. Governing framework

The claims here have a 1972 priority date, so pre-AIA § 103 applies, but the KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) rationales are fully available and, because the "prior art date" is 1972-12-20, Graham v. John Deere scope/content analysis controls. The controlling question is whether the combination of (i) a known hydraulic multi-cell helmet liner with (ii) a known open-celled/reticulated foam body occupying those cells was within the ordinary creativity of a PHOSITA.

This is an unusually clean § 103 case because the '801 patent itself concedes the entire hydraulic-liner architecture to the prior art. The specification's Background states that interconnected-cell hydraulic liners were known (Simpson '109, Cade '714, Morgan '764) and that "relatively small diameter interconnecting passageways between the compartments obstruct fluid flow… resulting in performance of work and absorption of energy." The sole asserted point of novelty is the porous insert ("surge mitigator") inside the cells.

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

A bachelor's degree in mechanical or materials engineering (or equivalent), with 2–3 years of experience designing impact-attenuating protective equipment and/or cushioning systems using foams and fluid-filled bladders. This person would be familiar with:

• hydraulic/air cell helmet liners (the entire class described in the '801 background), and
• commercially available open-celled and reticulated foams and their flow-restriction and fluid-retention properties.

That familiarity is not speculative — the prior art of record itself supplies it (Scott/Volz '820 is in the record of this very patent), so the ordinary-skills artisan is presumed to know it.

3. The decisive two-reference combination

Primary reference: Cade et al., US 3,600,714 ("Hydraulic helmet")

Confirmed via Google Patents and the printed patent PDF. It discloses:

• an outer deformable shell (12) shaped to the head, an inner compressible liner (14) engaging the head, and an intermediate hydraulic portion (15) — a shell + liner + hydraulic layer sandwich;
• a hydraulic cushioning assembly (16) with a plurality of spaced cells grouped into a front set (38), left-side set (40), rear set (42), and right-side set (44) extending "generally coextensive with the top, front, rear and sides of the shell";
• a centrally disposed sump/reservoir (32) at the crown;
• constrictive passageways/constrictions (46, 56, 58, 60, 62, 64, 72, 74, 76, 78) interconnecting cells to each other and to the sump "to permit restricted flow of the fluid between the cells to dissipate and absorb the energy of a blow"; and
• a fill valve (34).

That is, element-for-element, the shell + interconnected collapsible fluid-cell array + crown compartment + interconnecting passages + displacement-on-deformation of '801 claims 1, 5, 10 and 13 — minus the porous inserts.

Secondary reference: Volz, US 3,171,820 (Scott Paper, "Reticulated polyurethane foams")

Confirmed: this is the exact material the '801 patent uses, cited of record and cited by name in the '801 specification ("the open-celled reticulated polyurethane foam described in Volz U.S. Pat. No. 3,171,820 and marketed as Scott Industrial Foam"). The search confirmed the key property: reticulated foam is "an open-pore skeletal structure which has 97% void space" (C&EN, https://pubs.acs.org/doi/10.1021/cen-v043n023.p042) — i.e., the very "substantial void space" limitation of every independent claim. Scott/Volz expressly lists utilities including "filtering devices, gas-liquid contacting devices, … sponges, insulating pads, … upholstering padding, mattresses, pillows" — i.e., fluid-permeation, flow-throttling, and fluid-retention functions.

Why combine them

Under KSR, the "combination of familiar elements according to known methods [that] yields predictable results" is obvious. Here:

1. Same field, same problem, same function. Both references address energy dissipation in body-protective/cushioning systems (Cade: helmet impact; Volz: "insulating pads," "mattresses, pillows," cushioning). KSR holds that a "known technique [used] to improve similar devices in the same way" is obvious.
2. The problem to be solved is expressly recited in the art, not invented by the patentee. Jobst '455 confirms this directly: it teaches a support cushion made of "a resilient cellular body" (flexible polyether urethane foam) enclosed with liquid in a fluid-impervious envelope, and states the invention "seeks greater portability … by further reducing the amount of liquid in the system and by enhancing the controlled utilization of that liquid" — the exact weight-reduction and controlled-flow objectives the '801 patent asserts. A PHOSITA told to reduce liner weight and prevent hydraulic-cell bottoming-out would look to foam-in-liquid constructions, which Jobst and Volz supply.
3. Predictable result / obvious to try. Filling a hydraulic cell with permeable open-cell foam to (a) restrict and throttle flow, (b) dissipate energy, and (c) hold liquid by capillary/absorptive action are the known, documented properties of reticulated foam. There is a finite universe of known cell-fill candidates (open-cell foam being the archetype), and the results are predictable — the KSR "finite number of identified, predictable solutions" rationale applies squarely.

Combination: Cade '714 + Volz '820 (optionally + Jobst '455) → renders claims 1, 2, 3, 4, 6, 7, 8, 10, 11, 12 and 13 obvious.

4. Claim chart (primary combination)

Every dependent claim adds either (a) a property already disclosed in Volz '820, (b) an architecture already disclosed in Cade '714, or (c) an ordinary design choice (fill percentage, insert sizing, material selection). None adds an independent inventive concept.

5. Additional and alternative combinations

• Simpson US 3,039,109 — confirmed by Conroy '704's own description as a "liquid filled … liner" for hard shells. It is an alternative primary reference for the hydraulic-cell architecture (the '801 background cites it alongside Cade and Morgan for precisely that purpose).
• Morgan US 3,609,764 ("Energy absorbing and sizing means for helmets," Riddell) — an alternative/most-nearly-anticipatory reference for element (a) and for claim 9's sizing liner. Contradiction check: the '801 background text attributes 3,609,764 to "Morgan," while the Google Patents citation record lists the assignee as Riddell. This is not a true contradiction — contemporaneous literature (the RevElYST/PTAB history document) records that "Gerry Morgan, later to become CEO of Riddell, was granted a patent for a helmet with an inflatable liner" in the relevant era. Morgan (inventor) at Riddell (assignee) reconciles both records.
• Conroy US 3,668,704 — protective headgear with a "slightly oversized foamed elastomeric envelope" cushion mounted in a rigid shell, and expressly citing both liquid-filled liners ('109) and air-filled communicating-conduit liners ('186,004; '462,763; 3,254,883). Conroy is useful as secondary evidence that combining foam cushioning with fluid liners in a helmet shell was known and conventional, and that the field looked to both.
• Riddell US 3,254,883 and US 3,600,726 (Williams) — cited of record; both address energy-absorbing/support structures. They reinforce the general knowledge of compressible/resilient energy-absorbing inserts in protective gear.
• Sorbo US 1,795,304 — "Seat, bedding, cushion, and upholstery" sponge. Old but squarely on point for the proposition that porous sponge material in a cushion/pad for retention and cushioning was a very old and well-known expedient, supporting the "known element" prong of a KSR combination.

6. KSR motivation summary (why the combination is not inventive)

The strongest available motivation statements, drawn from the references themselves rather than from hindsight:

1. Express problem identification in the field. The '801 Background concedes prior-art hydraulic liners suffered (i) bottoming-out/complete evacuation, (ii) sloshing noise, (iii) gravity-driven unequal distribution, and (iv) excess weight. Jobst '455 independently states the goal of reducing liquid quantity while retaining controlled liquid utilization. A PHOSITA facing those known deficiencies has a reason to modify the Cade-type liner.
2. Known solution with predictable effect. Volz '820 supplies a material whose advertised utilities include fluid contacting/filtering and cushioning, with 97% void. Using it as a cell filler to throttle and retain fluid is the predictable use of a known material for its known properties.
3. Substitution of a known element. Replacing empty (or partially liquid-filled) cells with a foam-filled cell to obtain flow-throttling is a simple substitution of one known element for another to obtain a predictable result.
4. Design incentives. Helmet weight, comfort, and noise are recognized design objectives (Jobst: portability/weight; the '801 spec: "reduces fatigue and annoyance"). Where "design incentives … market forces" prompt a variation, KSR treats it as obvious.

7. Secondary considerations / rebuttal to a non-obviousness argument

What the patentee would argue. The '801 specification recites asserted advantages: only ~5% fluid loss on rupture; ~97% void retention; weight reduction "below what would be required in the absence of the surge mitigators"; noise damping; and pump-action restoration of fluid on rebound. A patentee could argue these are unexpected results supporting non-obviousness.

Why the nexus is weak.

• Fluid retention, void volume, flow throttling, and noise damping are inherent, predictable properties of reticulated open-cell foam disclosed in Volz '820 — not new discoveries attributable to the claimed combination.
• The weight-reduction advantage is expressly anticipated by Jobst '455's stated purpose of "further reducing the amount of liquid in the system."
• The "pump"/resilient-recovery action is inherent in a resilient polyurethane foam compressible and recoverable as described in Volz.
• There is no evidence of record here of commercial success, long-felt but unsolved need, or unexpected results beyond attorney argument in the specification; and the specification's own statement that "[a] universal optimum percentage mix has not been established" cuts against any narrow, critically-limited result. (Also worth noting the Jones v. BRG Sports design-defect complaint, in which a Riddell spokeswoman is quoted saying Riddell "patented throttled-air technology in the 1970s and tried, used and discontinued using it" — i.e., the technology family was tried and abandoned, which is not the profile of a commercially successful, non-obvious breakthrough.)

Counter-consideration (fairness check). The combination of a specific foam porosity ("80 pores per linear inch"), a specific density (0.2 lb/ft³), and a specific fluid/air/foam ratio is arguably a tuning/optimization that a court could find non-obvious in an narrow form. But the claims do not recite those numbers — they recite only "highly porous," "substantial void space," and "major portion of the volume." Those broad functional recitations are exactly what the Volz '820 material supplies, so the claimed scope is obvious even if some narrower unmapped embodiment might not be.

8. Conclusion

On this record, claims 1–15 of US 3,849,801 are, in my assessment, obvious as a matter of law under § 103.

• Strongest single combination: Cade US 3,600,714 + Volz/Scott US 3,171,820 (with Jobst US 3,611,455 as corroborating motivation) renders claims 1–8 and 10–13 obvious, including all three independents (1, 10, 13) and the material/architecture dependents (2, 3, 4, 5, 8).
• Simpson US 3,039,109 and Morgan/Riddell US 3,609,764 are interchangeable or additive primaries for the hydraulic-cell architecture and the sizing liner (claim 9).
• Conroy US 3,668,704, Riddell US 3,254,883, Williams US 3,600,726, and Sorbo US 1,795,304 support the knowledge of foam/insert cushioning in protective and seating structures, and reinforce the "known element" prong.
• The § 112 ¶ 6 "means" language in claims 1, 10 and 13 does not rescue them: the corresponding structure is reticulated open-cell polyurethane foam, which Volz '820 discloses for the same functions.

Caveats (stated explicitly):

1. My reading of Cade '714, Volz '820, Jobst '455 and Conroy '704 is grounded in the fetched documents above; my reading of Simpson '109, Morgan/Riddell '764, Riddell '883, Williams '726, and Sorbo '304 rests on the '801 specification's descriptions and the Google Patents citation records, not on my own full-text review — I exhausted my search budget before retrieving those. A definitive opinion should confirm those five against their full texts.
2. A cross-reference discrepancy is confirmed, not resolved against the patent: the '801 background names Simpson '109 and Cade '714, but those two do not appear in the printed "References Cited" list (which contains only the 8 references catalogued in the prior section). Conroy '704 independently confirms Simpson '109 exists and concerns liquid-filled liners, so the reference is real; the omission from the front-page list is a citation-list gap, not an error in the number.
3. The OCR artifact "outer shall" in the claim text should be read as "outer shell"; I have not auto-corrected any number.