Guide Wire Joint Member Design for Catheter Insertion
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Solution Overview
Problem
Existing guide wires fail to reliably prevent the catheter from being caught on turned-up portions of the coating layer during insertion into a living body lumen.
Innovation Solution
A guide wire design featuring a flexible elongated wire body with a resin coating layer, a cylindrical member, and a joint member with a gradually decreasing outer diameter, where the joint member is softer than the cylindrical member, and the cylindrical member is made of a metal material, ensuring smooth catheter insertion by preventing the catheter from being caught on the turned-up portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin coating layer is applied to the wire body to protect it, then the wire body is protected and has smoother surface, but the coating layer may turn up at the proximal side causing the catheter to be caught
Solution Approach 1:
A cylindrical member is introduced as an intermediary component between the wire body and the coating layer. This cylindrical member has a distal portion positioned proximate the proximal portion of the coating layer and a gradually decreasing outer diameter portion that prevents the coating layer from turning up, thereby eliminating the harmful effect without compromising the protective function of the coating layer.
2Strength
If the cylindrical member has a constant outer diameter to maintain structural integrity, then the structure is simple and strong, but it creates a step discontinuity that may catch the catheter
Solution Approach 1:
The cylindrical member is designed with varying outer diameter along its length. The distal portion has a constant outer diameter for structural integrity, while the proximal portion has a gradually decreasing outer diameter that creates a smooth transition surface. This local variation in geometry eliminates the step discontinuity that would otherwise catch the catheter, while maintaining the strength where needed.
3Ease of manufacture
If the joint member is made of the same material as the cylindrical member, then the manufacturing process is simplified, but the joint may be too rigid causing stress concentration
Solution Approach 1:
The joint member is made of a material with different mechanical properties (softer material) compared to the cylindrical member. This parameter change in material properties allows the joint member to deform more easily, distributing stress more uniformly and preventing stress concentration at the joint between the cylindrical member and the wire body.
Data Source
AI summary
A guide wire has a wire body; and a distal side coating layer that covers a distal portion of the wire body. The guide wire has a cylindrical member that has an outer diameter substantially the same as an outer diameter of a proximal portion of the distal side coating layer, that encircles a portion of the wire body and that has a distal portion positioned proximate the proximal portion of the distal side coating layer; and a joint member that is disposed at a proximal side of the cylindrical member and joins the cylindrical member and the wire body. The joint member has a gradually decreasing outer diameter portion whose outer diameter gradually decreases toward a proximal side of the wire body, and an outer peripheral surface of the cylindrical member has a surface continuous with the gradually decreasing outer diameter portion.