Cap Seal Structure for Writing Implement Air Pressure Control
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Solution Overview
Problem
Conventional writing implement cap mounting structures risk damaging the airtight seal portions due to ink adhesion and poor air tightness, and sudden cap operations can lead to ink leakage or air pressure issues.
Innovation Solution
A writing implement design featuring a cap with a backwardly projecting rear end shell and a ring-shaped outward facing seal, and a barrel with a forwardly projecting front end shell, where the seals contact radially and a ventilating hole allows communication between the inner and outer caps when not in close contact, preventing ink adhesion and air pressure issues during cap mounting and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cap is mounted suddenly, then the cap mounting operation is performed quickly, but the air in the inside of the cap cannot be sufficiently discharged to the outside causing pressurization
Solution Approach 1:
The notch is formed in advance in the ring-shaped projection to create a predetermined air discharge path. This preliminary structural arrangement ensures that when the cap is mounted suddenly, air can immediately escape through the pre-configured notch without causing pressurization, resolving the contradiction between mounting speed and air pressure control.
2Productivity
If the cap is removed suddenly, then the cap removing operation is performed quickly, but the air within the cap can be decompressed causing ink to leak out
Solution Approach 1:
The notch is pre-formed in the ring-shaped projection to establish a controlled air discharge mechanism before cap removal. When the cap is suddenly removed, the notch regulates air escape to prevent rapid decompression and ink leakage, thus resolving the contradiction between removal speed and air pressure control.
3Device complexity
If the airtight seal portion is exposed to the outside, then the seal structure is simple, but the airtight seal portion can be damaged by accident causing poor air tightness
Solution Approach 1:
The ring-shaped projection with the airtight seal portion is nested within the cap structure rather than being exposed. The seal portion is positioned inside the cap body, protected by the cap's outer structure, which prevents accidental damage while maintaining a relatively simple overall seal design. This nesting approach resolves the contradiction between structural simplicity and reliability.
4Ease of operation
If the pen tip contacts with the ring-shaped projection during cap mounting, then the cap can be mounted on the barrel, but ink adheres to the ring-shaped projection causing damage and poor air tightness
Solution Approach 1:
The notch is locally formed in the ring-shaped projection at a specific position to create a non-contact zone. This local modification allows the cap to be mounted on the barrel while preventing the pen tip from contacting the airtight seal portion, as the notch provides clearance or redirects the mounting interface. This resolves the contradiction between ease of operation and air tightness reliability.
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
Prevents damage to the airtight seal portions, avoids ink adhesion, and ensures proper air pressure management during cap operations, maintaining airtight conditions and preventing ink leakage.
Implementation Method 1
an interior of the inner cap and an exterior of the outer cap are allowed to communicate with each other through the ventilating hole
Implementation Method 2
an outward facing seal portion and an inward facing seal portion which, when the cap is mounted onto the barrel, closely contact with each other in a radial direction
Data Source
AI summary
The outer surface of an inner cap 3 is fixedly secured to the inner surface of an outer cap 4. In the opened end portion of the inner cap 3, there is formed a rear end shell portion 31 which projects backwardly. On the outer peripheral surface of the rear end shell portion 31, there is provided a ring-shaped outward facing seal portion. In the front end portion of a barrel 6, there is formed a front end shell portion 61 projecting forwardly. In the inner peripheral surface of the front end shell portion 61, there is formed a ring-shaped inward facing seal portion. When a cap 2 is mounted on the pen tip 8 side of the barrel 6, the outward facing seal portion can be closely contacted with the inward facing seal portion in the radial direction.