Guide Wire Projection Tapering Prevents Coating Peeling

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Solution Overview

Problem

Conventional guide wires experience issues where the proximal portion of the resin coating layer peels off, leading to a crack and potential entrapment of medical instruments like catheters due to a turned-up portion, especially when the distal portion is curved with a small radius.

Innovation Solution

A guide wire design featuring a projection with a tapering outside diameter that decreases towards the proximal end, where the projection is composed of a material different from the core wire and includes recesses or a tubular/coiled member, engaging with the coating layer to prevent peeling and ensure smooth catheter insertion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the distal portion of the guide wire is curved with a small radius of curvature, then the guide wire can navigate tighter turns and reach target sites more effectively, but the proximal end of the resin coating layer and the distal end of the annular member separate, producing a crack and causing the coating layer to peel and turn up

Engineering Contradiction:
Improveability to navigate curved pathsVSAvoidcoating layer integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The guide wire is divided into distinct functional segments: a flexible distal portion for navigation, a proximal portion with an annular member for structural support, and a resin coating layer for protection. The projection element acts as a separate component that bridges these segments, preventing separation when the wire is curved.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The projection element serves as an intermediary component between the annular member and the resin coating layer. It maintains continuous contact with both components, preventing separation and crack formation when the guide wire is curved, thus ensuring coating layer integrity while allowing the distal portion to be curved.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the proximal portion of the resin coating layer peels off, then the guide wire structure becomes compromised, but this creates a turned-up part that can catch on and damage the catheter during insertion

Engineering Contradiction:
Improveguide wire structural integrityVSAvoidcatheter damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The projection element is designed to prevent the resin coating layer from peeling off in the first place. By maintaining continuous contact with both the annular member and the coating layer, it counteracts the separation force that would cause peeling, thereby preventing the harmful turned-up condition before it can occur and protect the catheter from damage.

Inventive Principle:
Principle #9Preliminary anti-action

3Ease of operation

If the projection is disposed at a proximal portion with an outside diameter tapering portion that gradually decreases, then the catheter can slide smoothly over the projection during insertion, but the projection must be precisely positioned to maintain its protective function

Engineering Contradiction:
Improvecatheter insertion smoothnessVSAvoidprojection positioning accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The projection element has different geometric characteristics at different locations: the proximal portion has a tapering outside diameter for smooth catheter passage, while the distal portion maintains a larger diameter for effective engagement with the resin coating layer. This local differentiation allows the single component to simultaneously facilitate easy operation and maintain precise positioning function.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2554210B1Guide wire
Publication Date: 2019.01.16 TERUMO KK
  • EP2554210B1 patent drawingFigure 1
  • EP2554210B1 patent drawingFigure 2(a)~2(c)
  • EP2554210B1 patent drawingFigure 3

AI summary

A guide wire includes: a flexible elongate wire body; and a coating layer that covers a distal portion of the wire body and is formed of a resin material. The wire body of the guide wire is provided with a projection that protrudes along the entire circumference of an outer circumferential portion of the wire body. A distal portion of the projection is in contact with a proximal portion of the coating layer, and the maximum outside diameter of the projection is larger than the outside diameter of the coating layer that is in contact with the projection. In addition, a proximal portion of the projection has an outside diameter tapering portion where the outside diameter is gradually reduced toward a proximal end.