Collapsible Container Cap with Interference Fit Seal

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Solution Overview

Problem

Conventional collapsible container dispensing systems face issues with leakage due to cohesive or adhesive failure of glues and hermetic seals under pressure, which can degrade over time or react with chemically reactive components, and impose manufacturing constraints on cap geometries, limiting dispensing configurations.

Innovation Solution

A collapsible container dispenser system featuring a cap with an inner and outer collar, where a gap between the collars allows a folded section of the flexible container wall to form a self-sealing interface as the container collapses, enhancing the seal and facilitating efficient dispensing without the need for additional sealing materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glues or hardenable compositions are applied between the cap and collapsible container to form a seal, then the seal provides structural connection and barrier function, but the seal is prone to cohesive or adhesive failure and can degrade over time or react adversely with the materials in the package

Engineering Contradiction:

Improveseal reliabilityVSAvoidseal durability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention removes the sealing function from the chemical adhesive and transfers it to the mechanical interference fit between the cap's collar and the container's rim. The adhesive is extracted from its sealing role and retained only for structural bonding, eliminating the conflicting requirements of chemical stability and seal integrity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using chemical adhesion to create the seal, the invention inverts the approach by using mechanical interference - the collar's external dimensions are made slightly larger than the rim's internal dimensions, creating a press fit that generates sealing pressure through friction and normal forces.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If a hermetic seal is formed between the cap and collapsible container under positive pressure, then leakage is prevented, but the sealing mechanism imposes engineering and manufacturing constraints on the allowable geometries of the cap

Engineering Contradiction:

Improveleakage preventionVSAvoidcap geometry flexibility

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the geometric parameters of the collar and rim to create an interference fit. The collar's external diameter is made slightly larger than the rim's internal diameter, and the collar length is optimized to provide sufficient sealing surface area while maintaining manufacturability through conventional processes.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the outlet port of the cap is positioned in line with the longitudinal axis of the collapsible container to form an adequate seal, then sealing is improved, but this constrains the types of dispensing configurations that may be used with the collapsible container

Engineering Contradiction:

Improveseal qualityVSAvoiddispensing configuration flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention segments the sealing function from the outlet port positioning. The collar provides the seal at the container opening, while the outlet port can be independently positioned at various locations and angles on the cap, allowing flexible dispensing configurations without compromising seal integrity.

Inventive Principle:

Principle #1Segmentation

4Device complexity

If conventional sealing methods are used between the cap and collapsible container, then assembly is simplified, but leakage occurs due to adhesive failure under pressure

Engineering Contradiction:

Improveassembly simplicityVSAvoidseal integrity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The invention creates a composite sealing system combining the rigid collar structure with the flexible container rim. The interference fit between these two components with slightly different mechanical properties creates a reliable seal that accommodates pressure variations while maintaining assembly simplicity.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS9238544B2Article and method for sealing a collapsible container

Publication Date: 2016.01.19 3M INNOVATIVE PROPERTIES CO

AI summary

Articles and related methods are provided, the articles including a collapsible container having a flexible wall and enclosing material to be dispensed, a cap secured to one end of the container, the cap including an outlet, an inner collar at least partially surrounding the end of the container, and an outer collar at least partially surrounding the inner collar, and a gap provided between the inner collar and the outer collar, the gap having a size sufficient to receive a folded section of the flexible wall as the container collapses and the material is dispensed through the outlet.