Screw Closure Bucket Lid Structure for Drop-Test Sealing

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Solution Overview

Problem

Existing containers for transporting dangerous goods fail to adequately prevent unintentional opening or bursting during drop tests due to deformation of the lid plate and container walls, leading to potential leaks.

Innovation Solution

A multi-part closure system comprising a lid plate, locking ring, and sealing ring, where the lid plate is fixed to the container with a locking ring, and a sealing ring is positioned between the lid plate and the container rim, ensuring a positive fit that stabilizes the closure against deformation, with additional features like centering sections and reinforcement ribs to enhance stability and sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple lid plate and screw ring closure is used, then the device complexity is reduced, but the reliability during drop tests deteriorates due to plate shifting and deformation

Engineering Contradiction:
Improveclosure structureVSAvoidclosure stability during drop test
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The closure is divided into multiple functional components: a lid plate for sealing, a locking ring for mechanical fixation, and a receiving section on the container rim for positive engagement. This segmentation allows each component to perform its specific function optimally while working together to provide reliable closure during drop tests.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lid plate is nested within the receiving section of the container rim, with the locking ring enclosing both the lid plate and the receiving section. This nested arrangement creates a compact, integrated closure system where each component is positioned precisely to provide stable protection during impact.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If the lid plate is loosely placed on the container, then the ease of operation is improved, but the protection against unintentional opening during drop tests becomes insufficient

Engineering Contradiction:
Improvelid placementVSAvoidprotection against unintentional opening
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The receiving section is pre-formed on the container rim with a geometry that positively engages the lid plate before the locking ring is fully tightened. This preliminary engagement ensures that the lid plate is correctly positioned and secured during normal operation, while the locking ring provides additional reinforcement during drop tests to prevent unintentional opening.

Inventive Principle:
Principle #10Preliminary action

3Weight of moving object

If the container side walls are made thinner to reduce weight, then the weight is reduced, but the side walls deform under stress preventing the plate from covering the entire opening

Engineering Contradiction:
Improvecontainer weightVSAvoidside wall deformation under stress
Core Design Contradiction:
Weight of moving objectVSStability of the object's composition

Solution Approach 1:

The receiving section on the container rim is designed with enhanced local strength and rigidity to compensate for thinner side walls. This localized reinforcement at the critical closure interface allows the container to maintain structural integrity during drop tests without requiring the entire container body to be heavier.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4257504B1Container with a screw closure
Publication Date: 2026.03.11 SCHOELLER ALLIBERT GMBH
  • EP4257504B1 patent drawingFigure 1~2
  • EP4257504B1 patent drawingFigure 3~4
  • EP4257504B1 patent drawingFigure 5~6

AI summary

Container (1), in particular a plastic container, preferably in the form of a bucket, with a closure (2) for closing the container (1) with: a closed lid plate (4) which can be placed on a container rim (10) defining the container opening to cover a container opening; a locking ring (8) which can be placed over the lid plate (4) and screwed to the container (1), by means of which the lid plate (4) can be fixed to the container (1); and a sealing ring (6) arranged between the container rim (10) and the lid plate (4) for sealing the container opening. The lid plate (4) has an edge section with a receiving section (12), in particular U-shaped, which receives the container rim (10) and surrounds it radially from the inside and outside.