Ballpoint Pen Tip With Serrated Double-Molded Shaft
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Solution Overview
Problem
Existing ballpoint pens with elastic tips face limitations in flexing range and wobbling issues due to the gap between the shaft body and tip member, leading to inconsistent writing sensations and inability to vary line thickness effectively.
Innovation Solution
A ballpoint pen design featuring a writing ball retained by a holder with a swaged section, an ink supply section, and a tip shaft formed by double molding in a serrated pattern, allowing for adjustable angle and flexing according to applied force, enabling variable line thickness and improved writing expressiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an elastic body is interposed between the shaft body and tip member to enable tilting of the ballpoint pen tip, then the ballpoint pen tip can be tilted according to the force during writing, but the amount of flexing is limited by the gap between the shaft body and tip member and wobbling arises with degeneration of the elastic body
Solution Approach 1:
The tip shaft is segmented into multiple parts (first tip shaft part, second tip shaft part, third tip shaft part) with different materials and properties. The first part is rigid for structural support, while the second and third parts are elastic for flexing. This segmentation allows the tip to tilt and adapt to writing surface variations while maintaining writing stability through the rigid portion.
Solution Approach 2:
The tip shaft uses composite material construction with at least two different materials having different elastic moduli. The rigid material provides structural integrity and prevents wobbling, while the elastic material portions enable tilting motion according to applied force, resolving the contradiction between adaptability and reliability.
2Device complexity
If a single writing tip is used, then the structure is simple, but the thickness of drawn lines cannot be markedly varied according to the force applied during writing
Solution Approach 1:
The tip shaft is designed as a dynamic structure that changes its angle relative to the shaft body according to the force applied during writing. When writing with varying pressure, the elastic portions of the tip shaft flex at different angles, causing the writing ball to contact the paper at different effective angles, thereby varying line thickness dynamically without changing tips.
Solution Approach 2:
The invention changes the angular parameter of the tip shaft relative to the shaft body based on applied force. As writing pressure varies, the tip shaft angle changes, which directly affects the line thickness produced. This parameter change enables a single tip to produce multiple line thicknesses.
3Adaptability or versatility
If the tip shaft is made entirely elastic to enable flexing, then the writing sensation adapts to force applied, but the writing sensation becomes unstable with degeneration of the elastic body
Solution Approach 1:
The tip shaft is divided into rigid and elastic segments. The rigid first tip shaft part maintains structural integrity and provides stable writing sensation, while the elastic second and third parts provide force-adaptive flexing. This segmentation prevents the instability that would occur with fully elastic construction.
Solution Approach 2:
The tip shaft combines materials with different elastic moduli - rigid materials for structural stability and elastic materials for adaptive flexing. This composite construction ensures that the writing sensation remains consistent over time while still adapting to writing force variations.
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 design provides a stable writing sensation akin to a fountain pen and allows for drawing lines of different thicknesses using a single tip, enhancing writing expressiveness and quality.
Implementation Method 1
the tip shaft 12 exhibiting an elastic action
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
Provided are: a ballpoint pen with which the amount of bending of the pen tip can be changed by the force applied when writing, wobbling does not occur, and a stable writing feel can be obtained; and a ballpoint pen with which, to make it possible to clearly change the thickness of the drawn line by the force applied when writing, lines of different thickness can be written with a single writing tip using the angle of the ballpoint pen tip. The ballpoint pen is provided with: a writing ball (30); a holder (21) for holding the writing ball (30) by means of a swaged section (23) the tip of which has been swaged; an ink supply section (40) for supplying ink to the holder (21); a shaft body (11) inside which the ink supply section (40) is held; and a tip shaft (12), which is connected to the tip of the shaft body (11) and from which the holder (21) protrudes during writing. The tip shaft (12) is formed by two-color molding in which a front half (15) and a back half (16) are interdigitated in a saw tooth form.