Stranded Wire Point-Symmetric Core Design for Torsional Stress Relief

Solution Overview

Problem

Medical stranded wires face challenges in maintaining safety under high torsional stress, often leading to deformation or breakage during insertion into hard or occluded lesions, due to insufficient torque transmission characteristics.

Innovation Solution

A stranded wire design featuring a core element wire and side element wires, where the first side element wires are arranged point-symmetrically around the core, providing enhanced tensile strength and adhesion, while the second side element wires with lower tensile strength help alleviate torsional stress, preventing deformation or breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the stranded wire is designed with uniform high-strength element wires to ensure fatigue endurance, then the tensile strength is improved, but the wire becomes more susceptible to deformation or breakage under great torsional stress

Engineering Contradiction:

Improvetensile strengthVSAvoidsafety under torsional stress

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the tensile strength of element wires based on their functional requirements. First side element wires have higher tensile strength for torque transmission, while second side element wires have lower tensile strength to alleviate torsional stress. This localized differentiation of material properties resolves the contradiction between overall strength and torsional reliability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements asymmetry by creating an non-uniform distribution of element wire strengths around the core. The first side element wires (with higher strength) and second side element wires (with lower strength) are arranged in specific patterns, breaking the symmetry of uniform strength designs. This asymmetric arrangement allows the wire to handle torsional stress more effectively while maintaining torque transmission capability.

Inventive Principle:

Principle #4Asymmetry

2Duration of action of stationary object

If the stranded wire uses high-tensile-strength materials to ensure long-period fatigue endurance, then the durability is improved, but the deformation or breakage under great torsional stress during insertion cannot be prevented

Engineering Contradiction:

Improvefatigue enduranceVSAvoidsafety during insertion

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the tensile strength of element wires based on their functional requirements. First side element wires have higher tensile strength for torque transmission, while second side element wires have lower tensile strength to alleviate torsional stress. This localized differentiation of material properties resolves the contradiction between overall strength and torsional reliability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining element wires of different tensile strengths (first side element wires with higher strength and second side element wires with lower strength) to create a stranded wire with composite mechanical properties. This composite structure provides both fatigue endurance and torsional stress relief, resolving the contradiction between durability and insertion safety.

Inventive Principle:

Principle #40Composite materials

3Force

If the stranded wire is designed with point-symmetric arrangement of high-strength first side element wires, then the torque transmission characteristics are improved, but the complexity of the structure increases

Engineering Contradiction:

Improvetorque transmissionVSAvoidstructural complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The patent implements asymmetry by creating an non-uniform distribution of element wire strengths around the core. The first side element wires (with higher strength) and second side element wires (with lower strength) are arranged in specific patterns, breaking the symmetry of uniform strength designs. This asymmetric arrangement allows the wire to handle torsional stress more effectively while maintaining torque transmission capability.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent applies segmentation by dividing the side element wires into two distinct groups: first side element wires with higher tensile strength and second side element wires with lower tensile strength. This segmentation allows each group to perform its specific function optimally, improving torque transmission while managing structural complexity through functional differentiation.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP2896426B1Stranded wire and guidewire employing the same

Publication Date: 2019.05.29 ASAHI INTECC CO LTD

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AI summary

A stranded wire (80) is comprised a core comprising at least one core element wire (81) and a plurality of side element wires wound so as to cover a circumference of the core, the core and the plurality of the side element wires being stranded together. The side element wires include at least one pair of first side element wires (83) arranged point-symmetrically about the center of the core in a cross-sectional view of the stranded wire, and at least one second side element wire (84) other than these first side element wires (83). The core element wire (81) and the first side element wires (83) have tensile strength greater than that of the second side element wire (84).