Catheter Core Wire Joint Asymmetry
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Solution Overview
Problem
The existing balloon catheters face issues with plastic deformation of the core wire when a bending force is applied at the joint portion, as the force is concentrated, leading to potential deformation.
Innovation Solution
The catheter design includes a proximal shaft, distal shaft, and core wire with a joint surface featuring first, second, and third linear portions arranged in an angular U-shape, where the first and second joining means have different lengths, dispersing the bending force effectively along the longitudinal axis, reducing the likelihood of core wire deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the distal end portion of the proximal shaft is fitted into the inner cavity of the proximal end portion of the distal shaft with joining means, then the structural integrity of the catheter is improved, but the bending force becomes concentrated at the core wire contact point causing plastic deformation
Solution Approach 1:
The joint surface is divided into multiple linear portions (first, second, and third linear portions) arranged in an angular U-shape. This segmentation distributes the bending force across multiple contact points between the joining means and the core wire, preventing concentration of force at a single point and thereby preventing plastic deformation while maintaining structural integrity.
Solution Approach 2:
The angular U-shaped configuration of the linear portions creates an asymmetric joint surface that optimizes force distribution. The asymmetric arrangement ensures that bending forces are dispersed along the longitudinal axis through the angular geometry, reducing stress concentration at any single location and preventing core wire deformation.
2Strength
If the joining means is made longer to increase joint strength, then the connection between proximal shaft and core wire is improved, but the device complexity increases
Solution Approach 1:
The joining means is segmented into multiple linear portions with different lengths rather than using a single long continuous structure. This segmentation achieves the necessary joint strength through distributed contact points while keeping each individual segment compact, thereby avoiding excessive device complexity.
Solution Approach 2:
Different linear portions have different lengths optimized for their specific functions. The first and second linear portions have lengths that balance joint strength with flexibility, while the third linear portion connects the U-shaped configuration. This local optimization of dimensions provides sufficient joint strength without requiring an unnecessarily long or complex overall structure.
Data Source
AI summary
A catheter includes a proximal shaft, a distal shaft including a proximal end portion having an inner cavity into which a distal end portion of the proximal shaft is fitted, and a core wire extending through the inner cavity of the distal shaft. The core wire has a proximal end portion that is joined to a cutout portion formed in the distal end portion of the proximal shaft. Joining means are formed along a joint surface between the proximal end portion of the core wire and the cutout portion. When the joining means are divided into first joining means and second joining means along a longitudinal axis of the catheter, a length of one of the first joining means and the second joining means is larger than a length of the other of the first joining means and the second joining means.