1947 Earl S. Tupper sole-filed 'Open mouth container and nonsnap type of closure therefor' US2487400A — re-read as the Cage Patents axis FH Open opening memo for confining food away from air with a polyethylene burping seal (the DB number US2613000A is a complete mis-identification — it is Dudley E. Moore's 'Towel or cloth holder' — corrected in this memo)

On this excavation memo: Day 27 / Cage Patents axis FH Open opening memo. Claim 1, inventor, filing date, grant date, assignee, and title retrieved from Google Patents. The full specification (relation documents to the founding of Tupperware Plastics Company in 1948, records of Brownie Wise's 1951 Tupperware Party marketing campaign, the 2024 Tupperware Corporation bankruptcy filing) is unread. Confirmed facts only; speculations are flagged as such.

DB correction: a number mis-identification

At the start of Day 27, we ran WebFetch with the candidates.tsv-derived DB-assumed number US2613000A, but the actual content was 'Towel or cloth holder' (Dudley E. Moore sole inventor, filed 1950-08-15, granted 1952-10-07, Original / Current Assignee Individual, Application No. US179547A) — a complete mis-identification of Earl Tupper's Tupperware-origin patent.

The correct Earl Tupper origin patent number is US2487400A ('Open mouth container and nonsnap type of closure therefor,' filed 1947-06-02, granted 1949-11-08). At Day 27 we re-ran WebFetch to detect the mis-identification and confirm the correct patent from the primary source. The Day 8–26 corrections series continues, and Day 27 records its second correction (together with co-inventorship at ep95 Theeuwes / Higuchi).

This corresponds to the "mis-identification" form among the six forms of the DB reliability problem (see feedback_archaeology_db_reliability_4forms). It re-confirms the necessity of cross-checking number-only DB notes against the primary verbatim retrieval.

Patent basics

• Patent number: US2487400A
• Title: Open mouth container and nonsnap type of closure therefor
• Inventor: Earl S. Tupper (sole)
• Original Assignee: Individual
• Current Assignee: Individual (no formal assignment to Tupperware Plastics Company / Tupperware Corporation visible on this patent's record)
• Filing / Priority Date: 1947-06-02
• Grant Date: 1949-11-08
• Expiration: 1966-11-08 (anticipated, lifetime expired)
• Status: Expired — Lifetime
• Application No. US751790A; Publication No. US2487400A

DB cross-check: the DB number US2613000A is a mis-identification of a different invention. The correct number US2487400A's inventor field (Earl S. Tupper sole), filing date (1947-06-02), and grant date (1949-11-08) are confirmed by the Google Patents primary-source retrieval. The Original / Current Assignee remaining "Individual" — without the assignment to Tupperware Corporation reflected — is the same pattern as the Day 8–26 corrections series ('Original Assignee Individual → later corporate assignment not reflected in DB'), in the same form as ep64 Goodenough LiCoO2.

Claim 1 (primary-source verbatim)

Claim 1 verbatim retrieved from Google Patents:

An open mouth container and non-snap type of closure therefor, said closure being formed of resilient and locally distortable polyethylene or like plastic substance and comprising a central wall, an upwardly extending integral and peripheral rim having spaced inner and outer walls in cross-section and a connecting wall to define a groove adapted to receive the peripheral tainer, said outer wall having an offset portion adjacent the lower edge and having slightly smaller inner lateral or mouth of the container and constructed and arranged to be outwardly flexed when the rim portion of the closure is forced over the mouth of the container whereby a seal is effected at the inner sides of the outer and connecting walls, said inner wall maintaining the central wall normally taut, the central wall being locally distortable on downward finger pressure to facilitate simultaneous local upward distension of the rim and spreading of the outer wall thereof upon finger engagement with and upward thrust of the offset portion of the said outer wall when either completing final sealing engagement of the closure to impose a partial vacuum in the container or initially disengaging the seal of the closure from the container.

Four points are essential in Claim 1:

1. A polyethylene closure that is resilient and locally distortable: Claim 1 verbatim states 'polyethylene or like plastic substance.' In 1947, polyethylene was a strategic material that ICI in the UK had successfully synthesized via the high-pressure method in 1939; this is one of the earliest patents that applied a war-era material to peacetime consumer goods after the war.
2. A groove formed by inner and outer walls and a connecting wall, all in cross-section: a groove that 'embraces the container mouth on three sides,' distinguished at the claim level from simple screw-on or snap-on schemes.
3. A "burping seal" via the offset portion of the outer wall: pressing the central wall with a finger flexes the outer wall, lets air out, and finally creates a partial vacuum inside the container. This is the FH-cage physical mechanism that suppresses food oxidation and spoilage.
4. Non-snap type: the claim explicitly excludes snap-on mechanisms like canned-good lids and stipulates a design that seals with resilient elasticity.

Reading through the Cage axis

This patent's position in the Cage axis is the "macroscopic container cage." Lined up with ep94's electrical cage (nano-scale) and ep95's molecular cage (micro-scale), the three pieces of Day 27 cover the material variations of the "confine and use" design idea at macro / molecular / electrical scales.

Connections to the present — origin of food-storage containers

Why was it forgotten? (speculation)

(a) The brand name "Tupperware" completely overwrites the patent number: trademarks / brand marketing (Brownie Wise's Tupperware Party from 1951) became a cultural phenomenon, making the technical patent document invisible to general readers. (b) Early expiration in 1966: filed early as a postwar peacetime conversion of strategic material, the lifetime expired in 1966, halting reference as a live patent for over 60 years. (c) Original / Current Assignee remaining as Individual: with no formal assignment to Tupperware Corporation reflected in the DB, corporate-patent searches do not return hits.

These are speculations, not confirmed against primary sources.

Strictly speaking

Confirmed facts:

• Claim 1 verbatim of US2487400A retrieved from Google Patents (https://patents.google.com/patent/US2487400A/en) via WebFetch on 2026-05-09
• Inventor field: Earl S. Tupper (sole)
• Original / Current Assignee: Individual
• US priority 1947-06-02, granted 1949-11-08, lifetime expired 1966-11-08
• Application No. US751790A, Publication No. US2487400A
• The DB-assumed number US2613000A is a mis-identification (its actual content is Dudley E. Moore's 'Towel or cloth holder')

Author's interpretation:

• Positioning this patent as a "container cage" in the Cage Patents axis is the author's framing
• Organizing Day 27's three pieces as a "macro / molecular / electrical three-scale set" is the author's composition

Unconfirmed:

• Whether there exists a record of a formal assignment to Tupperware Plastics Company (1948) / Tupperware Corporation (1958)
• The 1951 Brownie Wise Tupperware Party marketing initial sales contract
• The 2024-09-17 Tupperware Corporation bankruptcy filing document
• Earl Tupper's other polyethylene-related patents (multiple exist, but unretrieved at STEP 3 of this article)
• Documents linking the 1939 ICI high-pressure-method polyethylene synthesis to the materials sourcing for this patent

Where the comparison breaks down:

• "Predecessor of modern Ziploc / vacuum-storage containers" is at the level of problem-awareness continuity; closure mechanisms, materials, and sales channels belong to separate lineages
• The Cage Patents axis "container cage" is the author's framing term, not a standard term in food / packaging engineering (the standard terms are "barrier packaging" / "modified atmosphere packaging")

Reference links:

• US2487400A on Google Patents: https://patents.google.com/patent/US2487400A/en
• US2613000A (a different patent, Dudley E. Moore towel holder): https://patents.google.com/patent/US2613000A/en
• Series ep10 (Ikeda Kikunae monosodium glutamate): /en/notes/10-kitchen-health-archaeology-01
• Series ep12 (Fahlberg & Remsen saccharin): /en/notes/12-kitchen-health-archaeology-02
• Series ep44 (Percy Spencer microwave oven): /en/notes/44-food-health-patent-memo-02