Endoscope Pull Wire Anchoring Mechanism for Tension Reduction
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Solution Overview
Problem
Conventional pull wire termination methods in endoscopes, such as crimping, often result in wire breaks at the capstan interface due to high wire tension, leading to reliability issues and reduced effectiveness in articulating the endoscope.
Innovation Solution
A pull wire anchoring mechanism that reduces holding tension by wrapping the proximal end of the pull wire around an insert component with a predetermined number of windings, utilizing a coefficient of friction to distribute the load and prevent wire breakage, while allowing for simplified assembly without additional cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional crimping methods are used to terminate pull wires to pulleys or capstans, then the assembly process is simple, but the holding strength is less than the tensile strength of the pull wire, resulting in wire breaks at the capstan interface
Solution Approach 1:
The patent introduces a sleeve as an intermediary component between the pull wire and the capstan. The sleeve features a reduced diameter section that fits over the capstan and a larger diameter section that provides a bearing surface for the pull wire. This intermediary structure distributes the tensile load over a larger area, preventing wire breakage while maintaining assembly simplicity through the sleeve's integrated design.
Solution Approach 2:
The patent transitions from direct one-dimensional wire-to-capstan contact to a two-dimensional contact interface by introducing the sleeve with its reduced and larger diameter sections. This dimensional change creates a bearing surface that distributes the tensile force across an area, thereby increasing holding strength without complicating the assembly process.
2Strength
If the pull wire is directly anchored to the capstan with high tensile strength, then the holding strength is maximized, but the wire tension is highest at the capstan causing wire breaks
Solution Approach 1:
The sleeve acts as a mediator that introduces a bearing surface between the pull wire and capstan. This bearing surface distributes the tensile load over a larger area, reducing the stress concentration at the wire-capstan interface and preventing wire breakage while maintaining adequate holding strength.
Solution Approach 2:
The patent changes the geometric parameters of the wire termination interface by introducing the sleeve with specific reduced and larger diameter sections. This parameter change creates a load-distributing bearing surface that reduces the maximum stress on the wire while maintaining the necessary holding strength through the friction and contact mechanics of the sleeved interface.
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 anchoring mechanism enhances the reliability of the endoscope by reducing holding tension, allowing the full tensile strength of the pull wire to be utilized, thereby improving the stability and longevity of the articulation system.
Implementation Method 1
utilizing a coefficient of friction to distribute the load and prevent wire breakage
Data Source
AI summary
An articulating flexible endoscope is provided. The endoscope comprises: a proximal portion comprising a driving mechanism for applying a force to a pull wire, the pull wire for articulating a bending section of the articulating flexible endoscope upon the force; and an anchoring mechanism coupled to the driving mechanism. A terminal end of the pull wire is configured to wind around the anchoring component with a pre-determined number of windings thereby reducing a holding tension at the terminal end of the pull wire.