Endoscope Pull Wire Tensioning Mechanisms for Knob Dwell
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Solution Overview
Problem
Conventional endoscopes experience shaft shrinkage due to environmental and sterilization conditions, leading to slack in pull wires, which results in unresponsiveness and an undesirable user experience known as knob dwell.
Innovation Solution
The implementation of tensioning mechanisms within the endoscope system to adjust and maintain tension in pull wires, including rotatable hubs, spring-activated devices, ratchet mechanisms, screw mechanisms, and rack and pinion systems, to eliminate or reduce slack and ensure proper functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pull wires are made freely slidable within the shaft to enable bending control, then ease of operation is improved, but shaft shrinkage causes slack in pull wires leading to knob dwell and reduced responsiveness
Solution Approach 1:
The tensioning mechanism is activated before use to remove slack from the pull wires by taking up excess length, ensuring that the control knobs are immediately responsive when the endoscope is first used, without requiring the user to compensate for slack during operation
Solution Approach 2:
The system changes the tension parameter in the pull wires by using a tensioning mechanism that applies force to remove slack, transforming the pull wire state from loose to taut, thereby improving control accuracy and responsiveness
2Ease of operation
If the insertion shaft is made of polymer material for flexibility, then ease of operation is improved, but the material shrinks under sterilization and environmental conditions causing slack in pull wires
Solution Approach 1:
The tensioning mechanism applies a pre-tensioning force to the pull wires that counteracts the expected shrinkage from sterilization and environmental exposure, maintaining proper tension despite the polymer shaft's dimensional changes over time
Solution Approach 2:
The system incorporates a dynamic tensioning mechanism that can adjust to changes in shaft length, allowing the pull wire tension to be maintained or recalibrated even as the polymer shaft undergoes thermal expansion or contraction during sterilization and use
3Ease of manufacture
If slack is present in pull wires after manufacturing, then ease of manufacture is improved, but knob dwell occurs requiring multiple rotations to achieve desired shaft bending
Solution Approach 1:
The tensioning mechanism is pre-configured or automatically activated during or after assembly to remove slack from the pull wires before the endoscope reaches the user, eliminating the need for manual adjustment and ensuring immediate control responsiveness
Solution Approach 2:
The system incorporates a self-adjusting tensioning mechanism that automatically removes slack from the pull wires without requiring manual intervention, using spring-loaded or ratchet-based mechanisms that self-regulate the tension as the shaft is assembled or deployed
Data Source
AI summary
An endoscope comprises a handpiece housing, an elongate flexible shaft extending from the handpiece housing, a pull wire extending from the handpiece housing into the elongate flexible shaft, and a tensioning mechanism configured to adjust tension in the pull wire. A method for adjusting tension in a pull wire of a controller for an endoscope comprises preparing an endoscope for use before a procedure, adjusting tension in a pull wire for deflecting a flexible elongate shaft of the endoscope to reduce knob dwell, and performing an endoscopic procedure with the endoscope.