Variable Torque Deflection Assembly for Catheter Shaft Control
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Solution Overview
Problem
Traditional catheter systems require high forces to deflect the distal region, leading to user fatigue and inconsistent performance during medical procedures, as they lack a mechanism to maintain constant force throughout deflection.
Innovation Solution
A deflecting assembly with a first and second rotatable member, where the second member is offset and has a smaller diameter, utilizing a first and second pull wire to create a variable torque, reducing the force needed to deflect the catheter shaft by maintaining torque increase as the distal region is deflected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional catheter systems use a simple pull wire mechanism for distal deflection, then the device structure remains simple, but high forces are required leading to user fatigue and inconsistent performance
Solution Approach 1:
The deflecting assembly is segmented into multiple rotatable members (first and second rotatable members) with different diameters, each contributing to the deflection mechanism. This segmentation allows the system to reduce the force required for deflection while maintaining structural functionality, directly addressing the contradiction between ease of operation and device complexity.
Solution Approach 2:
The deflecting assembly incorporates dynamic elements including rotatable members that can rotate during deflection, and a variable torque assembly that adjusts torque characteristics. This dynamic design enables the system to maintain constant force throughout the deflection process, improving ease of operation while the controlled complexity of moving parts is justified by the performance benefit.
2Ease of operation
If a variable torque assembly with multiple rotatable members is added to reduce deflection force, then ease of operation improves, but device complexity increases
Solution Approach 1:
The deflecting assembly uses a nested structure where the second rotatable member is positioned within or alongside the first rotatable member, with the second member having a smaller diameter. This nesting approach consolidates multiple functional elements into a compact arrangement, improving ease of operation through constant force while minimizing the increase in device complexity.
Solution Approach 2:
The variable torque assembly acts as an intermediary mechanism between the pull wire and the distal catheter section. It includes intermediate rotatable members and torque control elements that mediate the force transmission, transforming the pull wire's linear motion into controlled rotational motion that produces consistent deflection force, thereby improving operation ease while managing complexity through functional intermediaries.
3Ease of operation
If the second rotatable member is offset from the first, then mechanical advantage is increased reducing required force, but manufacturing precision requirements increase
Solution Approach 1:
The design intentionally introduces asymmetry by offsetting the second rotatable member from the first, creating an eccentric configuration that generates mechanical advantage during rotation. This asymmetric arrangement reduces the force required for deflection while the offset dimensions are designed to be manufacturable within standard tolerances, balancing ease of operation with reasonable manufacturing precision requirements.
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 deflecting assembly reduces the overall force required to deflect the catheter shaft, providing consistent performance and reducing user fatigue by maintaining a constant force throughout the deflection process.
Implementation Method 1
The first and second rotatable members are configured such that rotation of the first rotatable member via the first pull wire causes rotation of the second rotatable member and second pull wire resulting in deflection of a distal end of the medical device
Implementation Method 2
the deflecting assembly exhibits an increased mechanical advantage during deflection of the distal region of the catheter shaft
Data Source
AI summary
The present disclosure provides a medical device comprising a deflecting assembly configured to assist in deflecting a distal portion of a catheter shaft. The deflecting assembly may include a first rotatable member having a first diameter and a first pull wire coupled thereto and a second rotatable member having a second diameter smaller than the first diameter and a second pull wire coupled thereto, wherein the second rotatable member is coupled to the first rotatable member such that a center point of the second rotatable member is offset from a center point of the first rotatable member. The first and second rotatable members are configured such that rotation of the first rotatable member via the first pull wire causes rotation of the second rotatable member and second pull wire, thus resulting in deflection of a distal portion of the medical device.