Catheter Shaft Joining Strength via Mechanical Interlock
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing catheter shafts face challenges in maintaining sufficient joining strength, particularly when subjected to internal pressure from fluid injection, leading to potential separation or disconnection of the joined shafts due to insufficient crimping or adhesion methods.
Innovation Solution
The catheter shaft integrates a proximal and distal shaft with a high joining strength by incorporating a penetrating portion in the proximal shaft and a projecting portion in the distal shaft, where the distal shaft's projecting portion penetrates through the proximal shaft's penetrating portion, and is secured using crimping and heat, enhancing the joint's resistance to separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the distal shaft is inserted into the proximal shaft and fixed by crimping or adhesion, then the shafts are joined together, but the joining strength is insufficient to resist the separation force when fluid is injected
Solution Approach 1:
The distal shaft is inserted into the proximal shaft, creating a nested structure where the hollow interior of the proximal shaft receives the distal shaft. This nesting provides a mechanical interlocking foundation for the joint.
Solution Approach 2:
The projecting portion extends from the distal shaft in a radial direction perpendicular to the axial direction of the shafts. This radial extension creates a three-dimensional mechanical interlock that resists separation forces by engaging with the inner wall of the proximal shaft.
2Ease of operation
If the proximal shaft and distal shaft are made of different materials with different flexural stiffness, then the catheter achieves both pushing performance and followability, but the joint portion becomes vulnerable to separation under pressure
Solution Approach 1:
The proximal shaft is made of a material with high flexural stiffness for pushing performance, while the distal shaft is made of a material with lower flexural stiffness for followability. The joint portion incorporates a projecting portion that creates a localized mechanical interlock to strengthen the connection between these dissimilar materials.
3Ease of manufacture
If simple insertion and crimping methods are used to join the shafts, then the manufacturing process is simple, but the joining strength is insufficient under internal pressure
Solution Approach 1:
The projecting portion is pre-formed on the distal shaft before assembly. This preliminary action ensures that when the distal shaft is inserted into the proximal shaft, the mechanical interlock is already in place, providing inherent strength without requiring complex post-assembly operations.
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
This configuration significantly improves the joining strength between the shafts, preventing separation and disconnection even under pressure, while maintaining the catheter's flexibility and maneuverability.
Implementation Method 1
The proximal shaft includes a penetrating portion which penetrates from the inner surface through to the outer surface at the distal end of the proximal shaft. The distal shaft includes a projecting portion that includes a tip portion which extends through the penetrating portion past the inner or outer surface of the proximal shaft so that the tip portion is exposed.
Implementation Method 2
secured using crimping and heat, enhancing the joint's resistance to separation
Data Source
AI summary
A catheter including a catheter shaft that has a proximal shaft and a distal shaft. The proximal shaft and the distal shaft are joined to one another in the axial direction. The proximal and distal shafts are integrally connected to one another by the distal end of the proximal shaft being inserted into a hollow interior of the proximal end of the distal shaft or by the proximal end of the distal shaft being inserted into a hollow interior of the distal end of the proximal shaft. The proximal shaft includes a penetrating portion which penetrates from the inner surface through to the outer surface at the distal end of the proximal shaft. The distal shaft includes a projecting portion that includes a tip portion which extends through the penetrating portion past the inner or outer surface of the proximal shaft so that the tip portion is exposed.