Layered Grip Member Assembly for Writing Instruments
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Solution Overview
Problem
Existing writing implement barrels with soft inner and outer grip members face difficulties in assembly due to frictional resistance, are costly to produce, and can suffer from color mixing and hardness changes when fused, making them unsuitable for low-price products and aesthetically undesirable when transparent or semi-transparent outer members are used.
Innovation Solution
A barrel design featuring a grip member with an inner and outer member of different hardnesses, where at least one surface is formed in an assembly facilitating shape such as protruding and depressed or tapered, allowing easy assembly without fusion, enabling color differentiation and maintaining aesthetic appeal, with the outer member being detachable for replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the inner and outer members are made of soft materials and assembled by covering, then the grip provides comfortable feel and aesthetic appearance, but the assembly is difficult due to frictional resistance between the soft materials
Solution Approach 1:
The patent applies preliminary action by forming an assembly facilitating shape (protrusion or depression) on the inner member before assembly. This pre-formed geometric feature reduces the frictional resistance during the covering process, allowing the outer member to be easily slid over the inner member without requiring excessive force or complex assembly procedures.
2Strength
If the inner and outer members are joined by fusion, then the grip structure is strengthened, but the manufacturing cost increases and the respective hardnesses of the members change
Solution Approach 1:
The patent applies segmentation by maintaining the inner and outer members as separate, non-fused components. The assembly facilitating shape enables these segmented members to be assembled together without thermal or chemical fusion processes. This avoids the high manufacturing costs and hardness changes associated with fusion while providing sufficient structural integrity through the geometric interlocking design.
3Ease of manufacture
If the outer member is transparent or semitransparent and the inner and outer members are colored in different colors, then the aesthetic appearance is enhanced, but the colors mix in the interface when fused together
Solution Approach 1:
The patent applies segmentation by keeping the inner and outer members as distinct, non-fused components with clear geometric boundaries. The assembly facilitating shape creates a defined interface that prevents color mixing while maintaining aesthetic appearance. This allows the outer transparent/semitransparent member to showcase the inner member's color without the unwanted blending that occurs in fused structures.
4Stability of the object's composition
If the outer member is made to fit tightly on the inner member, then the grip structure is stabilized, but the outer member may displace when the inner member swells
Solution Approach 1:
The patent applies asymmetry by forming either a protrusion or depression (asymmetric geometric feature) on the inner member. This asymmetric shape creates a corresponding asymmetric fit with the outer member that provides stabilization while accommodating potential swelling. The asymmetric geometry ensures proper orientation and reduces displacement risk compared to a symmetric tight fit.
Data Source
AI summary
A barrel for a writing implement includes a barrel body having a gripping part, and a grip member of layered structure formed by assembling an inner member of a soft material and an outer member, and is put on the gripping part of the barrel body. The inner member is covered with the outer member, and at least one of the outside surface of the inner member and the inside surface of the outer member is formed in an assembly facilitating shape for facilitating putting the outer member on the inner member.