Segmented Guide Wire Core with Welded Projection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional guide wires face challenges in achieving both flexibility and operationality, as they often compromise on either flexibility at the distal end or rigidity at the proximal end due to the use of a single material core, and existing solutions like heat-treated Ni-Ti alloys have limitations in controlling flexibility and rigidity.

Innovation Solution

A guide wire design featuring a first wire with high flexibility made from a superelastic alloy and a second wire with higher rigidity made from a material like Co-based alloy, joined by welding with a projection at the welded portion to enhance joining strength and visibility under fluoroscopy, and optionally covered with a friction-reducing material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a material having a relatively high elastic modulus is used as the material of the core member, then the operationality of the guide wire is enhanced, but the flexibility of the distal end portion becomes lower

Engineering Contradiction:

ImproveoperationalityVSAvoidflexibility

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The guide wire is divided into multiple core members with different elastic moduli arranged in specific sections. The first core member (distal) has lower elastic modulus for flexibility, while the second core member (proximal) has higher elastic modulus for operationality. This segmentation allows each section to independently perform its required function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the guide wire are assigned different material properties tailored to their specific functional requirements. The distal end portion uses materials with lower elastic modulus to provide flexibility for navigating tortuous vessels, while the proximal portion uses materials with higher elastic modulus to provide rigidity for torque transmission and pushability.

Inventive Principle:

Principle #3Local quality

2Device complexity

If a material having a relatively low elastic modulus is used as the material of the core member, then the flexibility of the distal end portion is increased, but the operationality of the proximal end portion is degraded

Engineering Contradiction:

ImproveflexibilityVSAvoidoperationality

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The guide wire core is segmented into multiple members with different elastic moduli. The first core member (distal) has lower elastic modulus for flexibility, while the second core member (proximal) has higher elastic modulus for operationality. This segmentation allows each section to independently perform its required function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

3Device complexity

If heat-treatment is used to enhance the flexibility of the distal end portion of the alloy wire, then the flexibility is improved, but the rigidity of the proximal side may fail to be sufficient

Engineering Contradiction:

ImproveflexibilityVSAvoidrigidity

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

Instead of relying on heat-treatment to differentially affect one end of a uniform wire, the invention uses segmentation with multiple core members of different materials and elastic moduli. This provides more reliable and controllable differential mechanical properties than heat-treatment alone.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The guide wire employs composite construction with multiple core members made from different materials (e.g., Ni-Ti alloy, stainless steel, cobalt alloy) with different elastic moduli. This composite structure allows precise control of mechanical properties in different sections, overcoming the limitations of heat-treatment methods.

Inventive Principle:

Principle #40Composite materials

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 design improves operationality by providing high flexibility at the distal end, high rigidity at the proximal end, enhanced torque transmission, reduced friction, and improved visibility, leading to better trackability and safety during procedures like PTCA.

Implementation Method 1

the first wire and the second wire are joined to each other by welding, and a welded portion formed by welding has a projection projecting in the outer peripheral direction

Methodology Applied

Scientific EffectWelding: Welding

Implementation Method 2

a first wire disposed on the distal side of the guide wire... made from a superelastic alloy

Methodology Applied

Scientific EffectSuperelasticity: Pseudoelasticity

Data Source

PatentUS8124905B2Guide wire

Publication Date: 2012.02.28 TERUMO KK

AI summary

A method of making a guide wire involves butting a connection end face at a proximal end of a first wire against a connection end face at a distal end of a second wire while applying voltage and a pressing force to weld together the first and second wires at a welded portion. The welded portion forms a projection that projects outwardly in an outer peripheral direction relative to portions of the first and second wire adjacent the projection. The outer dimension of the projection at the welded portion is adjusted so that upon completing adjusting the outer dimension of the projection the projection still projects outwardly in the outer peripheral direction relative to the portions of the first and second wire adjacent the projection.