Dispensing Cap Segmentation for Sealing Stability

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Solution Overview

Problem

Existing dispensing caps with two components suffer from imprecise limit stop detection and potential product leakage due to residual torque causing stress and movement of the inner body, leading to unstable sealing.

Innovation Solution

A dispensing device with a single-piece inner body and a single-piece outer body featuring a snap-fit sealing mechanism, counter-abutments, and a threaded coupling that prevents rotation of the inner body when opening, ensuring a precise and stable limit stop and reduced interference for easier mounting and sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the outer component is completely unscrewed to reach the limit stop, then the cap opening is achieved, but residual torque is transmitted to the inner component causing stress and slight rotation

Engineering Contradiction:
Improvecap openingVSAvoidsealing stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The cap is divided into two independent components: an inner component that remains fixed on the container mouth and an outer component that rotates freely. This segmentation allows the outer component to be completely unscrewed without transmitting residual torque to the inner component, eliminating the rotation problem while maintaining sealing stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The limit stop mechanism is extracted from the inner component and transferred to the outer component. The outer component's rotation is limited by its interaction with the container mouth geometry, not by mechanical stops on the inner component. This allows complete unscrewing of the outer component without causing stress to the inner component.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If the inner component is fixed on the container mouth by friction, then the cap can be mounted, but the inner component undergoes stress and slight rotation when the outer component is unscrewed

Engineering Contradiction:
Improvecap mountingVSAvoidlimit stop precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

By segmenting the cap into inner and outer components with independent functions, the inner component can be simply mounted by friction without bearing the rotational stress. The outer component handles the rotation and limit stop function separately, improving overall precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The outer component acts as an intermediary between the user's rotational force and the inner component. It absorbs and manages the rotational motion and limit stop function, preventing direct transmission of stress to the inner component that would compromise sealing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the cap is designed with two components, then the limit stop can be defined, but the user cannot precisely determine when the limit stop is attained

Engineering Contradiction:
Improvecap structureVSAvoidlimit stop detection
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The limit stop function is extracted and implemented through the geometric interaction between the outer component and the container mouth. As the outer component is unscrewed, its rotation is naturally limited by the container mouth geometry, providing a precise and detectable limit stop position without complex mechanical stops.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides a precise and stable limit stop mechanism, preventing product leakage and reducing the force required for cap installation, allowing for precise control over cap opening and closure, even with softer materials like PP, PETG, or LDPE.

Implementation Method 1

a projecting thread (not numbered for simplicity but clearly visible in the drawings) is provided on the lateral wall 6, to be screwed onto a thread projecting from the outer surface of the container mouth 30

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

An annular snap-fit sealing bead is provided on a plug seal on the fitment for engaging a complementarily shaped snap-fit sealing groove formed on the interior surface of the container

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2468657B1Device for dispensing fluid substances, particularly creams
Publication Date: 2014.07.23 LUMSON SPA
  • EP2468657B1 patent drawingFigure 1~2
  • EP2468657B1 patent drawingFigure 3~4
  • EP2468657B1 patent drawingFigure 5~6

AI summary

A device for dispensing fluid substances, preferably creams, comprising a container (31) with which a cap is associated formed from an inner body (200) sealedly inserted into the mouth (30) and an outer body (201) superposed on the inner body (200), the outer body (201) presenting means for its coupling to the container which enable it to undergo axial translation relative to the inner body, from which an elongated appendix (2) projects presenting apertures for dispensing the product. The cap is operable between a closed position and a dispensing position. The container is provided with at least one abutment (50) adapted to oppose a counter-abutment (40) provided on the inner body (200) such as to prevent this latter from rotating relative to the container (31) in order to define said dispensing position.