Medical Device Control Handle Actuator Assembly Design
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Solution Overview
Problem
Existing medical device control handles are limited in their ability to independently control multiple puller wires, particularly in achieving bi-directional deflection and hands-free operation for complex medical procedures like atrial fibrillation treatment, where precise control and self-holding mechanisms are necessary.
Innovation Solution
A medical device control handle with an actuator assembly that includes a user interface rotational dial, a detent tab washer, and a spool, which allows for the independent control of multiple puller wires through rotational movement, preventing over-rotation and providing a self-holding mechanism for hands-free operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single puller wire is used for catheter deflection, then the device complexity is reduced, but bi-directional deflection capability is lost
Solution Approach 1:
The control mechanism is segmented into multiple independent actuator assemblies, each controlling a separate puller wire. This allows bi-directional deflection through multiple independent control elements while keeping each individual actuator relatively simple in design.
Solution Approach 2:
The actuator assembly design is made universal and multi-functional, capable of controlling different puller wires for various catheter manipulations including deflection, contraction, and other movements through a standardized interface.
2Adaptability or versatility
If multiple puller wires are added for enhanced control, then the adaptability and control precision are improved, but the device complexity increases
Solution Approach 1:
Multiple actuator assemblies are merged into a single integrated control handle housing, sharing common structural elements, mounting mechanisms, and spatial arrangement. This reduces overall device complexity while maintaining the capability to control multiple puller wires independently.
Solution Approach 2:
Each actuator assembly is designed as a universal module that can control different puller wires for various functions (deflection, contraction, etc.), allowing enhanced control capability without proportionally increasing complexity through standardized multi-functional components.
3Speed
If continuous control is used for puller wire actuation, then the responsiveness is improved, but user fatigue increases and hands-free operation is not possible
Solution Approach 1:
The actuator assembly incorporates a self-holding mechanism that automatically maintains the actuated position without requiring continuous user input. The mechanism serves itself by locking into position, eliminating the need for continuous control and reducing user fatigue while enabling hands-free operation.
Solution Approach 2:
The control mechanism transitions from continuous action to periodic action, where the user actuates the control element to a desired position and the self-holding mechanism maintains it. This periodic actuation reduces user fatigue while preserving rapid response capability when needed.
4Measurement precision
If rotational range is increased for greater manipulation precision, then the control precision is improved, but the risk of over-rotation and puller wire damage increases
Solution Approach 1:
The detent tab washer provides mechanical feedback through detent positions that indicate specific rotational angles. This feedback mechanism allows precise control within a safe range and prevents over-rotation by providing tactile and positional cues before damage can occur.
Solution Approach 2:
The limited rotation mechanism and detent tab washer provide preliminary anti-action by preventing the rotational movement from exceeding safe limits before puller wire damage can occur. This protective feature is built into the mechanism to counteract the risk of excessive rotation.
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
Enables precise bi-directional deflection and contraction of medical device components, such as catheter tips, allowing for more complex procedures like atrial fibrillation treatment with improved control and reduced user fatigue.
Implementation Method 1
washers include those rotationally coupled to the spool, and those that are either independently rotational (that is, not strictly rotationally coupled to another element) or those that are locked against rotation relative to the spool
Implementation Method 2
at least one washer is mounted on the shaft body of the spool to help apply compression load on the actuator assembly in friction-inducing contact with one or more components of the actuator assembly
Data Source
AI summary
A medical device control handle has with a distal component which is adjustable by an actuator assembly by means of a puller member or wire. The actuator assembly includes a user interface rotational dial, a detent tab washer and a spool, where the dial is rotationally coupled to the detent tab washer which transmits rotational movement of the dial to the spool. The spool has a shaft body and a drum end onto which an proximal end portion of the puller member can be wound to manipulate or adjust the distal component. Rotational movement of the detent washer is limited to prevent overrotation and breakage of the puller member. At least one washer is mounted on the shaft body of the spool to help apply compression load on the actuator assembly in friction-inducing contact with one or more components of the actuator assembly.