Endoscope Flexible Shaft with Pretensioned Proximal Spring

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Flexible endoscope shafts experience fatigue and increased flexibility in the proximal area due to alternating loads, leading to arching and buckling during insertion, which complicates precise positioning and can cause intestinal looping, and existing solutions are either complex or prone to fatigue.

Innovation Solution

A flexible shaft design with a second spring element having increased spring hardness through permanent pretensioning by axial compression, achieved using a traction element like a net-like sleeve, which stabilizes the shaft and reduces flexibility in the proximal area without widening the spring elements, thereby maintaining stability and reducing production complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the shaft is made flexible to enable navigation through branched structures, then the endoscope can reach internal body regions, but the proximal area becomes unstable and prone to arching during insertion

Engineering Contradiction:

ImproveflexibilityVSAvoidshaft stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The shaft is divided into multiple portions with different flexibility characteristics. The distal portion has higher flexibility to navigate branched structures, while the proximal portion has lower flexibility to maintain stability during insertion, preventing arching and looping in the gastrointestinal tract.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If the proximal area of the shaft is made stiffer to prevent arching, then shaft stability improves, but the shaft cannot adapt to curved paths in the intestine

Engineering Contradiction:

Improveshaft stabilityVSAvoidflexibility

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

Different portions of the shaft have locally optimized properties: the proximal portion is stiffer for stability during insertion, while the distal portion is more flexible for navigating curved anatomical paths, resolving the contradiction between stability and adaptability.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If spring elements are used to provide flexibility, then the shaft can bend and deflect, but alternating loads cause fatigue and increased flexibility over time

Engineering Contradiction:

ImproveflexibilityVSAvoidfatigue resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The second spring element is pre-compressed to a predetermined extent before use, creating initial tension that counteracts the effects of alternating loads during operation, thereby reducing fatigue and maintaining consistent flexibility characteristics over time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The pre-compression of the second spring element changes its mechanical parameters, increasing its resistance to fatigue from alternating loads while maintaining the required flexibility for shaft deflection during endoscope operation.

Inventive Principle:

Principle #35Parameter changes

4Stability of the object's composition

If the width of spring element turns is increased to reduce flexibility in the proximal area, then shaft stability improves, but production complexity increases

Engineering Contradiction:

Improveshaft stabilityVSAvoidproduction complexity

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

Instead of changing the geometric dimensions (width) of spring element turns, the invention uses pre-compression to alter the mechanical behavior of the second spring element, achieving reduced flexibility and improved stability while maintaining simple production processes.

Inventive Principle:

Principle #35Parameter changes

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 pretensioned second spring element enhances the shaft's resistance to arching and fatigue, maintaining stability and flexibility for precise endoscope positioning while simplifying production and reducing the risk of intestinal looping.

Implementation Method 1

at least a second spring element (52), at least the second spring element (52) being constructed from helical windings

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a spring hardness of the second spring element (52) being increased by a permanent pretensioning of the second spring element (52)

Methodology Applied

Scientific EffectPlasticity: Plasticity

Data Source

PatentUS7850604B2Flexible shaft for an endoscope and such an endoscope

Publication Date: 2010.12.14 KARL STORZ SE & CO KG

AI summary

A flexible shaft for an endoscope comprises a shaft body which, in the longitudinal direction of the shaft, has a first portion with a first degree of flexibility, and, proximally from the first portion, has at least a second portion with a second degree of flexibility which is less than the first degree of flexibility, the shaft body having, in the first portion, at least a first spring element, and, in the second portion, at least a second spring element. A spring hardness of the second spring element is increased by a permanent pretensioning of the second spring element, as a result of which the flexibility of the shaft body is reduced in the second portion.