Reduced-Diameter Bending Structure With Operation Wire Retention

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Solution Overview

Problem

Conventional bending structures face a limit in reducing diameter due to the potential for the end part of the drive wire to fall off when the drive wire breaks, necessitating a larger connection hole.

Innovation Solution

A bending structure that includes a movable part with a holding member to secure the end part of the operation wire, utilizing a case part as a holding member on the movable part to prevent the end part from falling off, even if the operation wire breaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the connection hole is opened to the outer circumference of the movable part to reduce the outer diameter, then the diameter reduction is achieved, but the end part may fall off at wire breakage

Engineering Contradiction:

Improvediameter of bending structureVSAvoidholding of end part

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The holding function is segmented from the movable part itself and assigned to a separate holding member. This allows the connection hole to be opened for diameter reduction while the holding member provides reliable retention of the end part through its dedicated holding structure, resolving the contradiction between size reduction and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The holding member acts as an intermediary component between the movable part and the end part. It provides the necessary holding function without requiring the connection hole to remain closed, enabling diameter reduction while maintaining reliable retention of the end part even if the operation wire breaks.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the entire end part is stored in the connection hole of the movable part, then the end part is held securely, but the diameter reduction is limited

Engineering Contradiction:

Improveholding of end partVSAvoiddiameter of bending structure

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The holding function is segmented from the movable part and transferred to a dedicated holding member. This allows the connection hole to be opened for diameter reduction while the holding member provides reliable retention of the end part through its specialized structure, eliminating the need to maintain a closed connection hole.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The holding function is extracted from the movable part's connection hole structure and implemented as a separate holding member. This extraction enables the connection hole to be opened for diameter reduction while the holding member independently provides the necessary retention capability for the end part.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentEP4640169A1Bending structure and surgical tool using same

Publication Date: 2025.10.29 NHK SPRING CO LTD

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AI summary

Provided is a bending structure capable of achieving a reduced diameter. The bending structure comprises: a bending part 11 which performs bending and stretching; a movable part 13 which is provided at a movable side end that operates according to the bending and stretching of the bending part 11; an operation wire 17 which is inserted through the bending part 11 and the movable part 13, has an end 17a on the movable part 13, and is for causing the bending and stretching; and a case part 27 which is mounted on the movable part 13 and holds the end 17a of the operation wire 17 on the movable part 13.