Offset Segmented Writing Instrument Refill for Ink Capacity and Flexibility
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Solution Overview
Problem
Conventional writing instruments with multiple refills face challenges in achieving high ink capacity while maintaining productivity and flexibility, especially when designed for curved shapes.
Innovation Solution
A writing instrument refill with a flexible first portion and a second portion of larger cross-sectional area, where the center of figure of the first portion is offset from the center of figure of the second portion, allowing for increased ink capacity and flexibility, and produced using injection molding for high productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the cross-sectional area of the ink container is increased to extend writing distance, then the ink capacity is improved, but the flexibility and ability to form curved shapes deteriorates
Solution Approach 1:
The refill is divided into multiple sections along its longitudinal axis, with each section having a different cross-sectional area. This segmentation allows the refill to have both large capacity sections for ink storage and smaller flexible sections that can be curved, resolving the contradiction between ink capacity and flexibility.
Solution Approach 2:
Different portions of the refill are designed with different cross-sectional areas to serve different functions. The larger cross-sectional areas provide ink capacity while the smaller cross-sectional areas provide flexibility for curving, allowing each local region to have the quality needed for its specific function.
2Quantity of substance
If the refill is designed with large ink capacity, then writing distance is extended, but manufacturing complexity increases
Solution Approach 1:
The refill integrates multiple functional sections (different cross-sectional areas) into a single unified structure. This merging of functions into one component achieves large ink capacity through varied geometry without requiring multiple separate parts, thereby reducing manufacturing complexity while maintaining high capacity.
Solution Approach 2:
The refill uses variations in geometric parameters (cross-sectional area along the length) to achieve different functions within a single component. By changing the cross-sectional area parameter along the longitudinal axis, the design achieves large capacity without increasing the number of parts or manufacturing steps.
3Adaptability or versatility
If the refill structure is made flexible for curved shapes, then adaptability is improved, but structural strength deteriorates
Solution Approach 1:
The refill is segmented into flexible portions with smaller cross-sectional areas and stronger portions with larger cross-sectional areas. This segmentation allows the flexible sections to be curved while the stronger sections maintain structural integrity, resolving the contradiction between flexibility and strength.
Solution Approach 2:
Different sections of the refill are designed with different cross-sectional areas to provide different local properties. The smaller cross-sectional areas provide flexibility for curving where needed, while the larger cross-sectional areas provide structural strength in regions requiring rigidity, allowing the refill to be both flexible and strong in appropriate locations.
Data Source
AI summary
In one embodiment, a writing instrument refill includes a first portion having flexibility, and a second portion having a cross-sectional area larger than a cross-sectional area of the first portion, wherein the center of figure of the cross section of the first portion is offset from the center of the figure of the cross section of the second portion, the first portion and the second portion are formed integrally, and a part of the first portion has an outer diameter smaller than an outer diameter of the other part of the first portion.