Catheter Braid Wire Joining via Surface Wrapping
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Solution Overview
Problem
Existing catheter designs face challenges in achieving high joint strength between thin wires in a braid reinforcement layer without using additional members like clips or adhesives, which hinders size reduction and material compatibility issues during laser welding.
Innovation Solution
The catheter features a braid with thin first and second wires joined by wrapping the distal end of the first wire around the side surface of the second wire, forming a joint that enhances strength without additional members, and allows flexible adjustment of joint strength by varying the covered surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of first wires and second wires is reduced for size reduction of catheter body, then the size of catheter is reduced, but the joint strength between wires is insufficient
Solution Approach 1:
The patent transitions from point-based joining (intersection points only) to surface-based joining by having the distal end portion of the first wire wrap around and cover the side surface of the second wire. This dimensional change from 0D (point) to 1D/2D (surface coverage) significantly increases the joint strength without increasing wire thickness, resolving the contradiction between size reduction and joint strength maintenance.
Solution Approach 2:
The distal end portion of the first wire is nested around the second wire, creating a layered structure where one wire is positioned within the space defined by the other wire. This nesting configuration increases the effective contact area and mechanical interlocking, thereby enhancing joint strength while maintaining thin wire dimensions for catheter size reduction.
2Strength
If another member such as clip or adhesive is used to join wires, then joint strength is improved, but the object of reducing braid thickness is not achieved
Solution Approach 1:
The patent employs self-service joining where the wires themselves perform the joining function through their own structural configuration. The distal end portion of the first wire automatically wraps around and secures the second wire through its own material and geometry, eliminating the need for external joining members like clips or adhesives. This maintains thin braid thickness while achieving sufficient joint strength.
Solution Approach 2:
The joining function is merged into the wire structure itself rather than being separate. The distal end portion of the first wire combines both structural and joining functions, integrating the connection mechanism directly into the braid composition. This merging eliminates additional members and maintains the thin profile of the braid while ensuring strong wire-to-wire connection.
3Ease of manufacture
If first wires and second wires are welded by laser beam at intersection points, then joining is achieved, but high joint strength cannot be secured when wire thickness is reduced
Solution Approach 1:
The patent replaces the thermal welding process (laser beam) with a mechanical joining process where the distal end portion of the first wire physically wraps around and covers the side surface of the second wire. This mechanical interlocking mechanism provides superior joint strength compared to laser welding, especially when wire thickness is reduced, while maintaining ease of manufacture through straightforward braiding and covering operations.
Data Source
AI summary
A body of a catheter includes an inner layer, a braid, and an outer layer. The braid includes first and second wires. The first and second wires can be joined together such that the distal end portion of the first wire winds itself around a side surface of the second wire. A joint includes a first joint portion positioned at the intersection point, a second joint portion positioned beyond the first wire in a width direction of the first wire, and a third joint portion positioned beyond the second wire in a width direction of the second wire. Thus, even when the first and second wires have small thicknesses for size reduction of the braid, the first and second wires can be joined together with high joint strength by increasing the area of the second joint portion or the thickness of the third joint portion.