External Pen Closure Design for Reliable Sealing

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Solution Overview

Problem

Existing pen designs face issues with reliable sealing and mechanical stress on the applicator tip due to internal closure mechanisms, which require significant force and can lead to buckling or contamination, especially when using elastic seals that are prone to plasticizer loss.

Innovation Solution

A pen design with an externally disposed closure that is transversely moved to seal the chamber, utilizing a biased elastic device, such as a coil spring, to provide tensile loading and support the closure, reducing mechanical stress and component count, while ensuring reliable sealing and dual functionality for both sealing and tip movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an internal sliding door closure is used within the chamber, then the through opening can be closed, but the closure requires considerable force to open and causes buckling of the sliding door

Engineering Contradiction:

Improvesealing functionVSAvoidforce required for opening

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The closure is inverted from an internal sliding door to an external closure disposed outside the chamber. This inversion moves the closure mechanism from within the chamber to the exterior, allowing it to be pushed transversely over the first through opening to close it, thereby eliminating the buckling problem while maintaining sealing reliability.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The closure is extracted from the internal chamber structure and positioned externally. By taking the closure out of the chamber interior and placing it outside, the design eliminates the structural constraints that caused buckling in internal sliding door configurations while preserving the sealing function.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If an elastic annular seal is used within the chamber, then the through opening can be closed, but the applicator tip is mechanically stressed and the seal is contaminated

Engineering Contradiction:

Improvesealing functionVSAvoidmechanical stress on applicator tip

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The closure is extracted from the chamber interior and positioned externally. This removes the source of mechanical stress and contamination from the applicator tip while maintaining the sealing function through the external closure mechanism.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The external closure acts as an intermediary between the chamber and the applicator tip, providing the sealing function without direct contact with the applicator tip, thereby eliminating mechanical stress and contamination issues.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a wedging configuration is used for the closure, then the sealing function is achieved, but the closure and opening require considerable force

Engineering Contradiction:

Improvesealing functionVSAvoidforce for closure and opening

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The closure mechanism is inverted from an internal wedging configuration to an external sliding closure. This inversion allows the closure to be pushed transversely over the through opening, eliminating the need for considerable wedging force while maintaining reliable sealing.

Inventive Principle:

Principle #13The other way round (Inversion)

4Device complexity

If the chamber is sealed from the inside, then the through opening can be closed, but the sealing function is less reliable compared to external sealing

Engineering Contradiction:

Improvesealing mechanismVSAvoidsealing function

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The sealing approach is inverted from internal sealing to external sealing. The closure is disposed outside the chamber and pushed transversely over the first through opening to close it, providing a more reliable sealing function that is easier to ensure mechanically.

Inventive Principle:

Principle #13The other way round (Inversion)

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 external closure design with a biased elastic device simplifies sealing and reduces mechanical stress on the applicator tip, enhancing reliability and reducing the risk of contamination and plasticizer loss, while maintaining efficient operation with fewer components.

Implementation Method 1

the closure is biased in a closure position in the direction of closing the first through opening... the elastic device is a spring, in particular a coil spring

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP2094508B1pen

Publication Date: 2015.09.02 STABILO INTERNATIONAL GMBH

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AI summary

The invention concerns a pen comprising an applicator tip (10), a chamber (18) for receiving the applicator tip (10) in a rest position, wherein the chamber (18) has a first through opening (20) through which the applicator tip (10) passes for moving from the rest position into an operative position, and a closure (36) for closing the first through opening (20). In accordance with the invention the closure (36) is on an outside of the chamber (18).