Medical Guide Wire With Variable Cross-Section Coil
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Solution Overview
Problem
Existing guide wires for medical tubes face challenges in production efficiency and irregularities due to separate formation of core and coil components, which can lead to difficulties in inserting catheters into somatic lumens, and limited control over bending rigidity at the distal end.
Innovation Solution
A guide wire with a core wire and externally mounted coil, where the cross-sectional shape of the coil varies in the lengthwise direction, allowing for precise adjustment of bending rigidity at the distal end, and is formed integrally with the core wire to improve production efficiency and reduce irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the core wire and coil are formed as separate parts and secured by brazing, then the guide wire structure can be assembled, but production becomes troublesome and irregularities occur on the outer circumferential surface
Solution Approach 1:
The coil and core wire are formed as a single integrated component through electroforming, eliminating the separate brazing process. This merging of parts resolves the contradiction by simultaneously improving production efficiency (removing assembly steps) and manufacturing precision (eliminating brazing-induced surface irregularities that could catch catheters).
Solution Approach 2:
The mechanical brazing process is replaced with an electroforming process that directly grows the coil structure onto the core wire. This substitution eliminates the harmful effects of brazing (surface irregularities, production complexity) while achieving the same structural integration, thus resolving both the ease of manufacture and manufacturing precision concerns.
2Adaptability or versatility
If the coil is externally mounted about the distal end portion of the core wire, then the guide wire gains flexibility, but the bending rigidity cannot be meticulously set
Solution Approach 1:
The cross-sectional shape of the coil wire varies along the length of the coil, creating different local properties. The proximal end has a larger cross-sectional area for stiffness, while the distal end has a smaller cross-sectional area for flexibility. This local variation allows meticulous control of bending rigidity at different portions of the guide wire while maintaining overall flexibility.
Solution Approach 2:
The cross-sectional area parameter of the coil wire is changed along the length of the coil. By gradually reducing the cross-sectional area from proximal to distal end, the bending rigidity is precisely controlled to provide sufficient stiffness for insertion while enabling flexibility for following curved lumens. This parameter change resolves the contradiction between flexibility and bending rigidity control.
Data Source
Figure 1~3
Figure 4A~4C
Figure 5A~5D
AI summary
Provided is a guide wire having a novel structure, with which it is possible to improve production efficiency and to effectively prevent large irregularities from forming on an outer circumferential surface of a core wire. Further provided is a guide wire having a novel structure, with which it is possible to more meticulously set bending rigidity to a distal end portion thereof. In a guide wire 10 such that a coil 14 is externally mounted about a distal end portion of a core wire 12, a proximal end portion of the coil 14 is integrally joined to the core wire 12 during formation of the coil 14. Furthermore, in a guide wire 10 such that a coil 14 is externally mounted about a distal end portion of a core wire 12, a cross-sectional shape of a wire 24 that constitutes the coil 14 varies in a lengthwise direction of the coil 14.