Writing Instrument Cap With Nested Cylinder Air Passage
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Solution Overview
Problem
Existing writing instrument caps lack sufficient mounting strength and do not provide an air passage to prevent suffocation in case of accidental ingestion.
Innovation Solution
A cap design featuring an endcap with an outer and inner cylinder, creating a ring-shaped space for increased mounting strength and an air passage, allowing the endcap to be securely fastened without enlarging the writing instrument's length or diameter, and incorporating a tubular mount for enhanced structural integrity and air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the endcap is attached to the projection by just the inside circumferential surface of the mounting hole, then the structure is simple, but the mounting strength is insufficient
Solution Approach 1:
The endcap is divided into an outer cylinder and an inner cylinder, creating a two-part structure. The outer cylinder engages with the cap body while the inner cylinder engages with the mount, distributing the mounting function across two separate engagement interfaces rather than relying on a single attachment point.
Solution Approach 2:
The inner cylinder is nested within the outer cylinder, forming a concentric structure. This nested arrangement allows both cylinders to engage simultaneously with different components (cap body and mount), effectively multiplying the mounting strength without significantly increasing the overall external dimensions.
2Strength
If the outside diameter of the cap body and endcap is increased to increase the contact area, then the mounting strength increases, but the outside diameter of the writing instrument increases
Solution Approach 1:
The nested cylinder structure allows the endcap to achieve increased mounting strength through internal engagement surfaces without proportionally increasing the external diameter. The inner cylinder engages with the mount while the outer cylinder engages with the cap body, creating multiple contact surfaces within the existing external dimensions.
Solution Approach 2:
Instead of increasing the external diameter in one dimension, the design adds a radial dimension by introducing a nested inner cylinder. This creates multiple engagement radii (outer cylinder outer surface and inner cylinder inner surface) that provide increased contact area without increasing the overall external diameter.
3Length of moving object
If the overall length of the writing instrument is kept at a predetermined size, then the writing instrument maintains standard dimensions, but the endcap cannot enter the cap body sufficiently
Solution Approach 1:
The nested cylinder configuration allows the endcap to achieve adequate engagement length within the constraints of the cap body depth. The inner cylinder extends further into the mount while the outer cylinder engages with the cap body, distributing the required engagement length across multiple components rather than requiring excessive penetration into a single component.
Data Source
AI summary
A writing implement (1) wherein the outer circumferential surface of a crown outer cylindrical section (21) fits into the inner circumferential surface of a case (11) and the inner circumferential surface of a crown inner cylindrical section (22) fits into the outer circumferential surface of an attachment body (12). In addition, an annular space (27) is formed in the crown (5), between the inner circumferential surface of the crown outer cylindrical section (21) and the outer circumferential surface of the crown inner cylindrical section (22). Air will flow through the annular space (27) even if, for example, the cap (2) becomes stuck in the bronchial tubes of an infant as a result of being accidentally swallowed by the infant. Suffocation accidents can, therefore, be reliably prevented.