Balloon Catheter Shaft Nesting for Outer Diameter Reduction
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Solution Overview
Problem
Existing balloon catheter manufacturing methods face challenges in preventing leakage and achieving a reduced outer peripheral length while maintaining sufficient pushing ability, particularly due to misalignment issues and increased outer diameter at fusion points, leading to transmission losses during use.
Innovation Solution
A balloon catheter design featuring a distal side shaft of resin, a proximal shaft of metal with an inclined portion and small diameter portion, and an inner tubular shaft disposed along the inclined and concave portions to prevent lumen communication, combined with a manufacturing method involving a heat-shrinkable tube to join the shafts, reducing the outer peripheral length and enhancing pushing ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If three shafts are fused together using heat and pressure, then the shafts are integrated, but the outer peripheral length increases at the fusion portion
Solution Approach 1:
The patent applies nesting by placing the inner tubular shaft inside the distal side shaft, and both inside the proximal shaft, creating a concentric multi-layer structure. This nested arrangement allows three separate shafts to be integrated while maintaining a compact outer diameter, as each shaft occupies a different radial layer rather than requiring additional axial or radial space for fusion.
Solution Approach 2:
The patent transitions from a planar arrangement of shafts to a three-dimensional concentric configuration. By organizing the shafts in radial layers around a central axis, the design achieves integration without increasing the outer peripheral length, effectively utilizing the third dimension (radial depth) to accommodate multiple components.
2Reliability
If a connection tube is connected to the proximal portion of the inner tubular shaft to prevent leakage, then leakage is reduced, but misalignment may still cause tube wall thinning
Solution Approach 1:
The distal side shaft serves as an intermediary component between the inner tubular shaft and the proximal shaft. By positioning the inner tubular shaft within the distal side shaft and both within the proximal shaft, the distal side shaft acts as a mediating structure that ensures proper alignment and spacing, preventing direct contact that would cause misalignment and tube wall thinning while still maintaining leakage prevention.
Solution Approach 2:
The patent divides the catheter shaft into three distinct segmented components (inner tubular shaft, distal side shaft, proximal shaft) that are stacked concentrically. This segmentation allows each component to be manufactured separately with precise dimensions, then assembled in a controlled manner that ensures proper alignment without requiring high-precision direct fusion, thereby preventing tube wall thinning while maintaining leakage prevention.
3Stability of the object's composition
If three shafts are disposed in overlapping positions along the axial direction, then integration is achieved, but the outer peripheral length increases
Solution Approach 1:
The patent implements nesting by arranging the three shafts in concentric layers along the radial direction rather than overlapping them along the axial direction. The inner tubular shaft is placed at the center, the distal side shaft surrounds it, and the proximal shaft surrounds both, creating a nested configuration that achieves integration while minimizing the outer peripheral length.
Solution Approach 2:
The patent reorganizes the spatial arrangement of the shafts from axial overlap to radial nesting. By utilizing the radial dimension instead of the axial dimension for layering the shafts, the design achieves integration of multiple components without increasing the outer diameter, effectively changing the dimension in which the shafts are arranged.
4Stability of the object's composition
If shafts are joined by fusion, then integration is achieved, but pushing force transmission is lost at joint points
Solution Approach 1:
The patent segments the catheter shaft into three distinct components that are mechanically coupled through friction and geometric interference rather than fusion. The inner tubular shaft, distal side shaft, and proximal shaft are stacked concentrically with tight tolerances that create frictional engagement, allowing pushing force to be transmitted through the stack without the weak points associated with fusion joints.
Solution Approach 2:
The patent employs a composite structure where three different shaft components (with potentially different materials and properties) are combined in a concentric arrangement. This composite design allows each component to contribute its strengths while the friction-based coupling between layers ensures efficient force transmission, avoiding the force loss that occurs at fusion joints in homogeneous structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents leakage and reduces the outer peripheral length of the catheter shaft, improving its pushing ability and manufacturing ease by ensuring precise alignment and communication states during the joining process.
Implementation Method 1
disposing a heat-shrinkable tube to cover a portion of the distal side shaft; and joining the distal side shaft, the inner tubular shaft, and the proximal shaft to each other by heating and shrinking the heat-shrinkable tube
Data Source
AI summary
A balloon catheter is disclosed having a distal side shaft formed of a resin material, a proximal shaft formed of a metal material, and an inner tubular shaft disposed along an inclined portion and a concave portion of the proximal shaft. The distal side shaft is joined to the proximal shaft at the small diameter portion on the proximal side from a distal opening of the proximal shaft. The distal opening of the proximal shaft is disposed on the distal side from a guide wire proximal opening.