Retractable Writing Tool Anti-Rattle Mechanism
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Solution Overview
Problem
Existing writing tools with anti-sway devices face issues of insufficient rattling prevention due to radially deformable O-rings or rings, which can cause the writing tip to stick, and require high-precision dimensional management to prevent rattling, making productivity challenging.
Innovation Solution
A projectable and retractable writing tool design featuring a shaft cylinder with a tip holder and an annular member connected via an elastic member, where the annular member has a cutout that reduces its inner diameter upon load reception, allowing for a rattling-free movement without the need for high-precision dimension management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an O-ring or ring is used as an anti-sway device, then the structure is simple, but the rattling prevention effect is insufficient and the writing tip may stick
Solution Approach 1:
The annular member is divided into multiple arc-shaped segments that can independently deform radially. Each segment can flex outward to accommodate the writing tip, preventing sticking while maintaining contact for rattling prevention. This segmentation allows the structure to remain simple while significantly improving its ability to prevent rattling and tip sticking.
2Reliability
If a spherical surface contact is used to prevent rattling, then the rattling prevention effect is enhanced, but high dimensional precision is required
Solution Approach 1:
The invention changes the contact mechanism from requiring precise spherical surface geometry to using a flexible annular member with arc-shaped segments. The segments can radially deform to accommodate dimensional variations, transforming a precision-dependent rigid contact system into a tolerance-friendly flexible contact system that maintains effective rattling prevention without high manufacturing precision requirements.
3Reliability
If the annular member is tightly fitted to prevent rattling, then the rattling prevention is effective, but the writing tip movement becomes restricted
Solution Approach 1:
The annular member transitions from a static tightly-fitted structure to a dynamic flexible structure with arc-shaped segments that can radially deform. During tip projection, the segments flex outward to accommodate tip movement, ensuring smooth operation. When the tip is stationary, the segments return to their original position to maintain contact for rattling prevention, thus dynamically adapting to different operational states.
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 solution effectively prevents rattling and ensures a stable writing experience by allowing the tip holder and annular member to move relative to each other, maintaining a rattling-free operation even without precise dimension control.
Implementation Method 1
an elastic member connecting the tip holder and the annular member such that the tip holder and the annular member are movable relatively to each other
Implementation Method 2
a cutout is formed at a part of the annular member such that an inner diameter of the annular member is reduced when a load is received by the contact surface
Data Source
AI summary
The present invention includes a shaft cylinder having an opening at a front end thereof, a tip holder movable in an axial direction of the shaft cylinder, a tip projectable and retractable in conjunction with a movement of the tip holder, an annular member fitted on the tip holder and axially movable, and an elastic member connecting the tip holder and the annular member so that they are movable relatively to each other. A contact surface tapered toward the front end is formed on an outer periphery of the annular member. A cutout reduces an inner diameter of the annular when a load is received by the contact surface. A guide surface is formed on the part of the inside surface of the shaft cylinder. The contact surface receives the load from the guide surface in conjunction with the movement of the tip holder toward the front end side.