Endoscopic Cable Guide for Head Stability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In medical endoscopic instruments with a double-jointed instrument head, external disruptive forces can cause undesirable changes in the orientation of the instrument head relative to the shaft, leading to instability and potential instrument failure.

Innovation Solution

The instrument features a cable guide with movable guide surfaces that can synchronize their movement transversely to the shaft's central axis, increasing the tension in the agonist cable pull and compensating for disruptive forces by adjusting the position of the guide surfaces to maintain equilibrium and prevent instrument head misalignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If cable pulls are used to control the instrument head directly, then the instrument head can be controlled to bend in desired directions, but external disruptive forces cause undesirable changes in orientation and potential cable failure

Engineering Contradiction:
Improveinstrument head controlVSAvoidinstrument head orientation stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A cable guide with movable guide surfaces is introduced as an intermediary component between the cable pulls and the instrument head. The guide surfaces can move transversely to the shaft axis to adjust the lever arm of the cable pulls, providing adaptive force distribution and protecting against disruptive forces while maintaining control capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cable guide is designed with movable guide surfaces that can dynamically adjust their position in response to external forces. This dynamic adjustment allows the system to adapt to varying load conditions and maintain optimal control throughout the range of motion, preventing cable failure and maintaining orientation stability

Inventive Principle:
Principle #15Dynamics

2Reliability

If the cable guide has movable guide surfaces that can move transversely, then the tension in cable pulls can be adjusted to compensate for disruptive forces, but the device complexity increases

Engineering Contradiction:
Improvecable pull equilibriumVSAvoidcable guide structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cable guide is designed to automatically adjust its guide surfaces in response to force imbalances without requiring external control mechanisms. The movable guide surfaces self-regulate to maintain cable tension equilibrium, reducing the need for complex control systems while improving reliability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The cable guide serves multiple functions: it guides the cable pulls, adjusts tension distribution, compensates for disruptive forces, and maintains instrument head orientation. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This configuration significantly reduces the impact of external disruptive forces on the instrument head, ensuring stable alignment and preventing cable pull failure, thus maintaining the instrument's functionality under external disturbances.

Implementation Method 1

the instrument head being mounted on a rolling element at the distal end of the shank trained rolling elements rolls off

Methodology Applied
Scientific EffectRolling friction: Roller

Data Source

PatentEP3454769B1Instrument, in particular medical endososcopic instrument
Publication Date: 2020.06.10 RICHARD WOLF GMBH
  • EP3454769B1 patent drawingFigure 1
  • EP3454769B1 patent drawingFigure 2~3
  • EP3454769B1 patent drawingFigure 4~6

AI summary

The invention relates to an instrument, in particular a medical endoscopic instrument. This instrument has a shaft (2) and an instrument head (8) arranged on the distal side of the shaft (2). The instrument head (8) is joined to the shaft (2) via a double joint (6) having two joint axes arranged at a distance to one another in the longitudinal direction of the instrument. In addition, the instrument has two control cables (52, 54) guided through the shaft (2), which are movingly coupled to the instrument head (8) in an antagonistically effective manner, and which are in contact, in the region of the distal end of the shaft (2), with two guide surfaces of a cable guide (58) facing one another in the radial direction of the shaft (2), wherein the guide surfaces of the cable guide (58) can be moved in the direction transverse to the central axis of the shaft (2).