Steerable Catheter Wire-Tensioning Spool and Gear Mechanism
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Solution Overview
Problem
Existing steerable catheters face challenges in providing finely tunable tensioning for small-diameter control wires, which is crucial for predictable and desirable steering behavior, especially in small-diameter endoscopes like cholangioscopes, as excessive or insufficient tension can lead to premature or undesired deflection.
Innovation Solution
A wire-tensioning mechanism featuring a first and second spool with rotatable gears and detents, allowing for secure attachment and adjustment of control wires, enabling precise tensioning between the proximal and distal ends, with the control wires being securely attached to gears and wound around them for stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If threaded tensioning bolts or pins are used to provide control wire tensioning, then the mechanism is simple in structure, but it cannot provide finely tunable tensioning for very small diameter fibers
Solution Approach 1:
The patent employs a dynamic tensioning mechanism where a movable element can be positioned at different locations along the control wire to adjust tension. This allows finely tunable tensioning by changing the position of the movable element, transforming a static threaded bolt system into a dynamic adjustable system that provides precise control over wire tension.
Solution Approach 2:
The patent changes the tensioning parameter from a fixed threaded bolt configuration to a variable position system. By allowing the tensioning element to be moved to different positions along the control wire, the system can precisely adjust the tension parameter to match the specific requirements of very small diameter fibers, achieving fine-tunability without excessive complexity.
2Reliability
If control wires are made taut to provide predictable steering behavior, then steering precision is improved, but premature or undesired deflection may occur due to excessive tension
Solution Approach 1:
The patent enables precise adjustment of the tension parameter in control wires. By allowing the tensioning element to be positioned at optimized locations, the system can set the wire tension to an optimal value that ensures predictable steering behavior without exceeding the threshold that would cause premature or undesired deflection of the catheter.
Solution Approach 2:
The patent incorporates a feedback mechanism where the position of the movable tensioning element can be adjusted based on observed steering performance. This allows the system to fine-tune wire tension to achieve the desired balance between steering predictability and prevention of premature deflection, optimizing performance through iterative adjustment.
Data Source
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AI summary
A spool and gear mechanism for tensioning and manipulating the steering/ deflection control wires of a steerable catheter device provides for a desired level of tension that will allow operation of the device without too little or too much tension in those wires. In a wire-tensioning mechanism for a steerable catheter, the mechanism includes at least a first and second steering/deflection control wire each attached to the spool by winding around its own detent-engaged rotatable gear in the spool and extending out through a radial wall of the spool to engage into a steerable catheter body. In a multi-spool system, the wire-tensioning/winding gears of each spool preferably are accessible for adjustment via apertures of an adjacent spool.