Liquid Applicator Engagement Structure for Secure Fixation

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Solution Overview

Problem

Conventional liquid applicators face challenges in easy assembly and secure attachment of the applying part, leading to potential detachment and leakage issues, with existing fixation methods being complex, costly, or providing insufficient holding force.

Innovation Solution

A liquid applicator design featuring a cylindrical applying part with indented and projected engaging portions on the inner and outer peripheries, combined with a joint and front barrel having matching engaging features, allows for robust fixation through engagement and fitting, enhancing assembly simplicity and preventing detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the applying part is fixed by nipping between inner and outer annular seats formed integrally, then the fixing structure is compact, but the manufacturing complexity increases and fixing force becomes insufficient

Engineering Contradiction:
Improvefixing structure complexityVSAvoidfixing force
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The integral annular seat structure is divided into separate inner and outer annular seats that can be assembled independently. This segmentation allows each seat to be optimized for its specific function and enables easier assembly while maintaining adequate fixing force through the combined action of both seats.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner annular seat is positioned within the outer annular seat, creating a nested configuration. This nesting arrangement allows both seats to work together to provide sufficient nipping force on the applying part while keeping the overall structure compact and manageable.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If the applying part is fixed by a single undercut engagement, then the assembly is simple, but the fixing force is insufficient

Engineering Contradiction:
Improveassembly simplicityVSAvoidfixing force
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Instead of relying on a single undercut engagement in one dimension, the invention introduces multiple engagement points distributed around the applying part. This multi-dimensional approach to engagement distributes the fixing force across multiple locations, significantly increasing overall holding strength while maintaining assembly simplicity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of repair

If the applying part is made detachable for cleaning, then the maintainability improves, but the risk of detachment during use increases

Engineering Contradiction:
Improvecleaning accessibilityVSAvoidattachment stability
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The annular seats are pre-formed with engagement features that create a secure initial attachment. This preliminary secure engagement ensures that even when the applying part is detached for cleaning and reattached, the connection remains stable and reliable, minimizing the risk of unintended detachment during use.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2319358B1Liquid applying tool
Publication Date: 2016.06.22 MITSUBISHI PENCIL CO LTD
  • EP2319358B1 patent drawingFigure 1
  • EP2319358B1 patent drawingFigure 2
  • EP2319358B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention is to provide a liquid applicator that can be easily assembled and whose applying part, front barrel and joint will not be easily coming off from each other. The present invention is a liquid applicator which, in its assembled state where the applying part 14, joint 30, front barrel 28 are fixed to a barrel body front end portion 10a, the step of an indented/projected engaging portion 14d on the inner peripheral side of the applying part rear end portion 14b is abutted from behind against and engaged with the step of an indented/projected engaging portion 30b on the outer peripheral side of the forward part of the joint 30. At the same time, an indented/proj ected engaging portion 14e on the outer peripheral side of the applying part rear end portion 14b is abutted against and engaged with an indented/projected engaging portion 28b on the inner peripheral side of the front barrel's forward part, and an indented/projected engaging portion 28c on the inner peripheral side of the front barrel rearward part is engaged with an indented/proj ected engaging portion 30c on the outer peripheral side in the rearward part of joint 30, whereby applying part 14, joint 30 and front barrel 28 are formed so as to fix the applying part 14 to barrel body 10 by means of the joint 30 and the front barrel 28.