Variable Torsional Rigidity Driving Shaft for Endoscope Insertion

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Solution Overview

Problem

Endoscopes with electric bending mechanisms face challenges in maintaining flexibility and reducing operator burden due to uneven maximum bending angles, leading to increased force requirements and potential flexibility loss during insertion and withdrawal, particularly in digestive tracts where resistance varies.

Innovation Solution

An insertion apparatus with a flexible tube and a driving shaft that adjusts torsional rigidity based on rotation direction, using a spiral shape portion and a driving shaft with alternating layers of hard steel wires, to transmit rotational force efficiently and maintain flexibility during both insertion and withdrawal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a driving shaft with high torsional rigidity is used to transmit rotational force efficiently, then the operator burden is reduced, but the flexibility of the insertion portion is compromised

Engineering Contradiction:

Improveoperator burdenVSAvoidflexibility

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The driving shaft incorporates alternating layers of hard steel wires wound in different directions (first and second winding directions), allowing the torsional rigidity to dynamically adapt based on the rotation direction. This dynamic structure provides high rigidity when force is needed while maintaining flexibility for bidirectional movement

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The driving shaft uses a composite structure with alternating layers of hard steel wires, combining materials with different properties to achieve both strength and flexibility. The alternating winding directions create a composite effect that balances rigidity and flexibility

Inventive Principle:

Principle #40Composite materials

2Power

If the driving shaft is rotated in the first rotation direction (winding direction) to transmit force, then propulsion is generated, but the driving shaft shortens and flexibility is reduced

Engineering Contradiction:

Improvepropulsion forceVSAvoidflexibility

Core Design Contradiction:

PowerVSAdaptability or versatility

Solution Approach 1:

The alternating layer structure allows the driving shaft to dynamically adjust its physical state based on rotation direction. During propulsion (first rotation direction), the structure provides necessary rigidity while preventing excessive shortening through the counterbalancing effect of alternating wire orientations

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If the maximum bending angle in one direction is increased to 210 degrees, then the observation capability is improved, but the burden on hand fingers increases when bending beyond 120 degrees

Engineering Contradiction:

Improvebending capabilityVSAvoidoperator burden

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent replaces the manual mechanical bending system with an electric bending mechanism. Motors are integrated to automatically pull the bending wires, substituting the operator's hand force with electric actuation. This eliminates the burden on hand fingers while maintaining the full 210-degree bending capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 apparatus reduces operator burden by optimizing propulsion forces and maintaining flexibility, preventing the driving shaft from shortening and ensuring consistent insertion and withdrawal capabilities without compromising the flexible tube's integrity.

Implementation Method 1

a single driving force transmitting member inserted along a longitudinal axis in the flexible tube and formed by being wound around an axis along a direction of the insertion in a coil shape, the single driving force transmitting member being configured to transmit the rotational driving force of the electric driving source to the driven portion by being rotated around the longitudinal axis by the rotational driving force of the electric driving source

Methodology Applied

Scientific EffectRotational force transmission:

Implementation Method 2

For the driving force transmitting member, first torsional rigidity in a first rotating state of being rotated in a direction of being wound in the coil shape is set higher than second torsional rigidity in a second rotating state of being rotated in a direction opposite to the direction of being wound in the coil shape

Methodology Applied

Scientific EffectTorsional rigidity:

Implementation Method 3

a flexible tube with flexibility that is extendedly provided along a longitudinal axis

Methodology Applied

Scientific EffectFlexibility: Elasticity

Data Source

PatentUS10105038B2Insertion apparatus

Publication Date: 2018.10.23 OLYMPUS CORPORATION(JP)

AI summary

An insertion apparatus includes: a flexible tube; an electric driving source arranged on a proximal end side of the flexible tube; a driven portion arranged on a distal end of the flexible tube; and a single driving force transmitting member inserted in the flexible tube and formed by being wound in a coil shape. For the driving force transmitting member, first torsional rigidity in a first rotating state of being rotated in a direction of being wound in the coil shape is set higher than second torsional rigidity in a second rotating state of being rotated in an opposite direction; and the driven portion performs a first motion by the first rotating state and performs a second motion requiring a larger amount of force than the first motion by the second rotating state.