Variable Mechanical Advantage Actuator for Stent Delivery
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Solution Overview
Problem
Current medical device delivery systems lack precise and controlled movement mechanisms for deploying medical devices like stents within body lumens, often resulting in inaccurate placement and insufficient control over the deployment process.
Innovation Solution
The system incorporates a mechanism with inner and outer tubes surrounded by an actuator that provides variable mechanical advantage as it moves, allowing for fine and controlled retraction of the outer tube through a combination of rotational and linear movements, enabling precise placement of medical devices within body lumens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple retraction mechanism is used for the outer tube, then the device complexity is reduced, but the precision and control of medical device placement deteriorates
Solution Approach 1:
The actuator provides variable mechanical advantage that changes dynamically during operation. Initially, when the outer tube is fully extended, the mechanical advantage is high to enable easy retraction. As the outer tube retracts, the mechanical advantage decreases, providing fine control for precise placement. This dynamic adjustment resolves the contradiction by having the mechanism adapt its complexity level to the operational phase.
Solution Approach 2:
The mechanical advantage parameter of the actuator changes continuously during the retraction process. The system transitions from high mechanical advantage (for coarse retraction) to low mechanical advantage (for fine adjustment). This parameter change allows a single mechanism to handle both coarse positioning and precise placement without requiring multiple separate mechanisms.
2Device complexity
If a constant mechanical advantage actuator is used, then the device complexity is reduced, but the ease of operation deteriorates due to lack of fine control
Solution Approach 1:
The actuator's mechanical advantage is designed to vary dynamically during operation. At the beginning of retraction, high mechanical advantage provides easy operation for coarse movement. As the outer tube approaches its final position, the mechanical advantage decreases automatically, enabling fine control for precise placement. This dynamic behavior enhances ease of operation across different phases without adding complexity.
Solution Approach 2:
The actuator automatically adjusts its mechanical advantage based on its position and the retraction progress. The system self-regulates the force multiplication ratio without requiring external control mechanisms. This self-service capability allows the actuator to provide both coarse and fine control automatically, improving ease of operation while maintaining relatively simple device architecture.
3Ease of operation
If the actuator provides high mechanical advantage throughout the entire retraction process, then the ease of operation is improved, but the manufacturing precision of placement deteriorates due to excessive force
Solution Approach 1:
The mechanical advantage is designed to decrease dynamically during the retraction process. Initially, high mechanical advantage makes retraction easy. As the outer tube retracts and the actuator moves, the mechanical advantage automatically decreases, reducing the force applied and enabling precise placement. This dynamic adjustment resolves the contradiction by having the system adapt force levels to operational needs.
Solution Approach 2:
The mechanical advantage parameter changes continuously during retraction. The system transitions from high force multiplication (for easy operation) to low force multiplication (for precision). This parameter change ensures that the actuator provides appropriate force levels at appropriate times, simultaneously achieving ease of operation and manufacturing precision.
4Device complexity
If a single actuator is used for the entire retraction process, then the device complexity is reduced, but the adaptability to different deployment stages deteriorates
Solution Approach 1:
The single actuator is designed with variable mechanical advantage that adapts to different deployment stages. During initial retraction, the actuator provides high mechanical advantage for easy operation. As the process progresses, the mechanical advantage decreases to enable fine control for precise placement. This dynamic adaptability allows one actuator to perform functions that would traditionally require multiple actuators.
Solution Approach 2:
The actuator is designed to perform multiple functions across different stages of the retraction process. It provides both coarse retraction and fine adjustment capabilities through its variable mechanical advantage. This multi-functionality allows a single actuator to replace what would traditionally require multiple specialized actuators, reducing device complexity while maintaining adaptability to different deployment stages.
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
This solution enables precise and controlled movement of medical devices, enhancing the accuracy of placement and allowing for both fine and coarse adjustments during deployment, improving the overall effectiveness of medical device delivery systems.
Implementation Method 1
The mechanical advantage of the actuator can change as the actuator moves
Data Source
AI summary
Medical device delivery systems, as well as related methods and components, are disclosed.