Endoscopic Instrument Angled Gap Design

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Solution Overview

Problem

Endoscopic instruments with flexible shafts face issues of fold formation between segments, leading to restricted pivoting mobility and potential hose perforation, due to the pinching of the outer tube, which existing solutions like additional braids or thick-walled hoses increase the instrument's diameter and assembly effort.

Innovation Solution

The design features segments with diametrically opposite joints and angled gaps between axial end edges, preventing hose penetration by maintaining a constant gap width and allowing for high mobility while preventing folds from entering, using a wavy or angled configuration that ensures the hose does not encroach on the gap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a sufficiently large gap exists between two adjacent segments to prevent movement limitation, then the shaft achieves high mobility, but the outer tube can be pinched and folded between the segments

Engineering Contradiction:
Improveshaft mobilityVSAvoidtube integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The gap between segments is extended in the axial dimension rather than only in the radial dimension. By creating a gap that extends axially beyond the segment length, the invention allows the tube to clear the gap without being pinched, while maintaining sufficient radial clearance for segment pivoting. This dimensional extension resolves the contradiction by providing both tube protection and segment mobility.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If additional braid or thick-walled tube is used to prevent creasing, then the tube becomes more resistant to folding, but the outer diameter of the instrument increases

Engineering Contradiction:
Improvetube resistance to creasingVSAvoidouter diameter
Core Design Contradiction:
ReliabilityVSArea of moving object

Solution Approach 1:

The invention extracts the protective function from the tube wall itself (which would require thickening or adding braid) and relocates it to the segment gap structure. By designing the gap to extend axially beyond the segment, the structure itself provides protection against pinching without modifying the tube wall thickness or adding external protective layers, thus maintaining the original outer diameter.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If many short segments are used to achieve angulation through small pivoting movements, then the gap between segments is minimized, but the assembly effort and bending radius increase

Engineering Contradiction:
Improveminimization of gap-related issuesVSAvoidassembly effort
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention uses a small number of longer segments rather than many short segments. Each segment is designed with joints at its axial ends, and the gap between segments extends axially beyond the segment length. This segmentation approach reduces the total number of segments and assembly operations while the extended gap design ensures tube protection is maintained regardless of segment count or length.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If the gap between segments is large to allow pivoting, then shaft flexibility is improved, but folds can enter the gap and restrict movement

Engineering Contradiction:
Improveshaft flexibilityVSAvoidfold formation in gap
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The gap is extended in the axial dimension beyond the segment length, creating a three-dimensional clearance space. This axial extension ensures that when segments pivot, the tube can clear the gap completely without forming folds that would restrict movement. The extended gap provides both the radial clearance needed for flexibility and the axial clearance needed to prevent fold formation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3122230B1Endoscopic instrument
Publication Date: 2020.07.22 RICHARD WOLF GMBH
  • EP3122230B1 patent drawingFigure 1~3
  • EP3122230B1 patent drawingFigure 4~5

AI summary

The invention relates to an endoscopic instrument having a shaft which has at least two segments that are connected by way of two diametrically opposed joints, between the axial mutually facing front edges of which, there is a gap, wherein at least once, the gap extends at an angle.