Catheter Movable Bending Manipulation Part Thermal Expansion
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Solution Overview
Problem
Catheters with metal and resin components face issues due to differing coefficients of thermal expansion and swelling, leading to excessive loads on manipulation wires and tubular main bodies during sterilization and environmental changes, causing wire breakage and deformation.
Innovation Solution
A catheter design with a movable bending manipulation part that adjusts the path lengths of manipulation wires, allowing for loosening or tightening without moving the tubular main body, thereby mitigating the effects of thermal and humidity-induced expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the catheter uses metal manipulation wires and resin tubular main body with different thermal expansion coefficients, then the structural strength and flexibility are improved, but large loads are applied to the manipulation wires during heating causing wire breakage
Solution Approach 1:
The patent introduces a movable bending manipulation part that can dynamically adjust the path length of manipulation wires in response to thermal expansion. During heating, the bending manipulation part moves to increase the wire path length, thereby reducing tension and preventing wire breakage. This dynamic adjustment resolves the contradiction between maintaining structural strength and preventing wire failure under thermal stress.
Solution Approach 2:
The patent changes the parameter of manipulation wire path length in response to temperature changes. By making the bending manipulation part movable, the system automatically adjusts the wire path length parameter during heating or swelling, reducing the tension parameter on the manipulation wires and preventing breakage while maintaining the beneficial thermal expansion properties of different materials.
2Reliability
If the tubular main body is moved forward to remove loosening of manipulation wires, then the wire tension is restored, but the tubular main body may be plastically bent under compressive force
Solution Approach 1:
The patent segments the manipulation system into a fixed manipulation-part main body and a movable bending manipulation part. This segmentation allows the bending manipulation part to independently adjust wire path length without moving the tubular main body, thereby restoring wire tension while avoiding compressive forces that could cause plastic bending of the tubular main body.
Solution Approach 2:
The movable bending manipulation part acts as an intermediary mechanism between the manipulation wires and the tubular main body. It absorbs the thermal expansion effects and adjusts wire path length without transmitting compressive forces to the tubular main body, thus preventing deformation while maintaining wire tension.
3Manufacturing precision
If the manipulation wires are tightly stretched during assembly, then the initial tension is optimized, but thermal expansion during sterilization creates excessive tension leading to wire breakage
Solution Approach 1:
The patent incorporates a preliminary design feature where the bending manipulation part is positioned to provide adequate wire path length before sterilization. This preliminary configuration ensures that during subsequent heating, the wire path length can increase to accommodate thermal expansion, preventing excessive tension and wire breakage while maintaining optimized initial tension for manufacturing.
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 prevents damage to manipulation wires and tubular main bodies during heating or swelling environments, ensuring a high-quality catheter by maintaining wire tension and reducing deformation risks.
Implementation Method 1
the coefficients of linear expansion and the swelling coefficients of the tubular main body and the manipulation wires are greatly different from each other. Specifically, the coefficient of thermal expansion and the swelling coefficients of the tubular main body are about 10 times greater than those of the manipulation wires
Implementation Method 2
the coefficients of linear expansion and the swelling coefficients of the tubular main body and the manipulation wires are greatly different from each other
Data Source
Figure 1(a)~1(c)
Figure 2
Figure 3
AI summary
A catheter of the invention includes an elongated flexible tubular main body; a plurality of manipulation wires inserted through the tubular main body and having tips connected to a distal part of the tubular main body; a manipulation-part main body provided at a base end of the tubular main body; and a bending manipulation part. The bending manipulation part has an engagement part engaging with base ends of the manipulation wires, and individually applies pulling force to the plurality of manipulation wires through pulling operations so as to bend the distal part of the tubular main body. The bending manipulation part is provided so as to be movable with respect to the manipulation-part main body. The path lengths of the plurality of manipulation wires from the tips thereof to the engagement part are simultaneously increased or decreased when the bending manipulation part and the manipulation-part main body move relative to each other.