Writing Instrument Erasing Member Attachment Structure
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Solution Overview
Problem
Existing writing instruments with erasing members face issues of loose attachment, making stable erasing difficult, and previous attachment structures require high press-fitting force, making insertion of the erasing member into the attachment hole challenging.
Innovation Solution
A writing instrument design featuring an erasing member with a fitting part and connecting parts that form a clearance space, a ring-shaped engagement projecting part, and a supporting wall for secure attachment, reducing frictional resistance and allowing easy attachment and stable erasing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the erasing member is strongly attached to the cap using a projecting part inserted into an attachment hole, then the attachment strength is improved, but the press-fitting force required for insertion increases significantly
Solution Approach 1:
The attachment structure is divided into multiple functional parts: a fitting part for insertion, connecting parts for structural support, and a ring-shaped engagement projecting part for securing. This segmentation allows each part to perform its specific function efficiently, reducing the overall force required for attachment while maintaining strong bonding.
Solution Approach 2:
The erasing member features a ring-shaped engagement projecting part with specific local geometric properties that concentrate the attachment force at key engagement points. This local quality enhancement allows strong attachment without requiring high press-fitting force across the entire interface.
2Ease of operation
If the cap and erasing member are not strongly attached to allow replacement, then the ease of replacement is improved, but looseness occurs during erasing operations
Solution Approach 1:
The attachment structure provides dynamic characteristics: strong attachment during erasing operations through the ring-shaped engagement projecting part, but allows easy replacement when needed. The corner part and lock part engagement mechanism enables controlled detachment while maintaining stability during use.
Solution Approach 2:
The erasing member is designed as a replaceable component with a simple attachment structure that allows easy replacement when worn. The fitting part and connecting parts enable quick detachment and reattachment, making the erasing member effectively a disposable or frequently replaceable component.
3Strength
If the contact area between the projecting part and attachment hole is increased, then the attachment strength is improved, but the frictional resistance increases making insertion difficult
Solution Approach 1:
The contact interface is segmented into distinct functional zones: the fitting part for insertion, the ring-shaped engagement projecting part for attachment, and the corner part with lock part for securing. This segmentation reduces the frictional resistance during insertion by limiting the contact area to only where necessary, while maintaining strong attachment through concentrated engagement points.
Data Source
Figure 1
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AI summary
A writing instrument (1) is provided with an erasing member (2) mounted to the rear end section of the writing instrument body (3) or to the front end section of a cap (4). The end section has a fitting section (14) which is disposed on the center axis and a connection section (15) which connects the end section and the fitting section (14). The erasing member (2) has a fitting hole (2c) which receives both the fitting section (14) and the connection section (15). When the erasing member (2) is mounted in position, a gap space (17) is formed around the connection section (15).