Steerable Sheath Tube Anchor Ring Traction Wire Connection
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Solution Overview
Problem
Existing adjustable bend sheath tubes face challenges in achieving sufficient tensile strength and fatigue resistance due to stress concentration and material strength reduction from welding, leading to potential fractures and reduced flexibility, which complicates repeated bending operations during minimally invasive surgeries.
Innovation Solution
The adjustable bend sheath tube employs a coaxially embedded anchor ring and a traction wire with a hooked connection method, allowing for flexible engagement without increasing the wall thickness, using annealed segments to enhance tensile and fatigue strength, and featuring parallel traction wire channels to distribute force effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to connect the traction wire to the radiopaque ring, then the connection strength is improved, but the material strength is significantly reduced and stress concentration occurs
Solution Approach 1:
The radiopaque ring serves as an intermediary component between the traction wire and the tube body. Instead of welding the thin traction wire directly to the tube wall, the ring acts as a mediator that distributes the tensile forces over a larger area, eliminating stress concentration while maintaining strong connection. The ring is embedded in the tube wall and provides a robust attachment point for the traction wire without compromising the tube wall integrity.
Solution Approach 2:
The connection system is segmented into three distinct components: the traction wire, the radiopaque ring, and the tube body. This segmentation allows each component to be optimized independently - the thin traction wire for flexibility, the radiopaque ring for force distribution and connection strength, and the tube wall for structural integrity. The radiopaque ring is divided into segments that can be separately embedded in the tube wall.
2Strength
If a thicker traction wire is used to increase tensile strength, then the connection strength is improved, but the tube wall thickness must be increased
Solution Approach 1:
The solution moves from a one-dimensional problem (thicker wire requiring thicker wall) to a two-dimensional solution by introducing the radiopaque ring as a separate dimensional element. The ring is embedded within the tube wall thickness, providing a large surface area for force distribution without increasing the overall tube outer diameter. This allows the traction wire to remain thin while achieving high tensile strength through the ring's distributed load-bearing capability.
3Object-affected harmful factors
If the tube wall is made thinner to reduce outer diameter, then the damage to blood vessels is reduced, but the traction system volume must be minimized
Solution Approach 1:
The radiopaque ring is nested within the tube wall structure, with the traction wire nested within the ring. This nested configuration allows the traction system components to be packed efficiently within the existing tube wall thickness without requiring additional wall thickness. The radiopaque ring is positioned between the inner and outer tube walls, utilizing the wall thickness space that would otherwise be unused.
4Stability of the object's composition
If welding is used for rigid connection, then the connection stability is improved, but the fatigue strength is poor and fracture risk increases
Solution Approach 1:
The connection system uses flexible embedding rather than rigid welding. The radiopaque ring is flexibly embedded in the tube wall, allowing it to deform elastically during repeated bending cycles. This flexible connection maintains stability while accommodating the dynamic bending motions required during surgery, preventing the stress concentration and fatigue failure that would occur with rigid welded connections.
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 design enhances the connection stability and strength between the traction wire and anchor ring, improving the tube's flexibility and reliability, reducing the risk of fractures and maintaining the thin wall thickness necessary for minimally invasive procedures.
Implementation Method 1
using annealed segments to enhance tensile and fatigue strength
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a steerable sheath tube (100) including a tube body (110), a traction mechanism (120) and a fixing and connecting mechanism (130). The traction mechanism (120) includes an anchor ring (121) and a traction wire (122). The anchor ring (121) is coaxially embedded in a distal elastic segment (111) of the tube body (110). The traction wire (122) is arranged in a side wall of the tube body (110), and extends along the axial direction of the tube body (110). The traction wire (122) includes a first segment and a second segment connected to each other, wherein the first segment is connected to the fixing and connecting mechanism (130) near a proximal end of the tube body (110), and the second segment hooks the anchor ring (121).