Medical Torque-Limiting Apparatus Deformable Driver Element
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Solution Overview
Problem
Existing medical torque-limiting devices are heavily dependent on manufacturing tolerances, making it challenging to maintain precision and avoid exceeding the limit torque, which is critical to prevent damage to medical implants during surgical procedures.
Innovation Solution
Incorporating deformable driver elements with deformation surfaces that change in distance from the longitudinal axis, allowing for precise selection and combination of driver elements to set the limit torque, minimizing the impact of manufacturing tolerances and enabling the device to remain non-rotatable below the limit torque while becoming rotatable at or above it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional torque-limiting devices are used with standard components, then the device structure is simple, but the manufacturing precision requirement becomes extremely high to ensure accurate limit torque
Solution Approach 1:
The driver element is segmented into multiple deformation sections (first, second, third deformation sections) with different deformation characteristics. Each section has a distinct contact surface geometry (different radii of curvature) that interacts with corresponding surfaces on the second component, allowing the limit torque to be determined by the sequential deformation of these segments rather than requiring ultra-precise manufacturing of a single monolithic component.
Solution Approach 2:
Different regions of the driver element are given different local properties through the deformation sections. Each deformation section has specifically tailored geometric characteristics (contact surface radius, thickness, material properties) that enable progressive deformation at different torque levels. This local differentiation allows the system to achieve high torque precision through the cumulative effect of multiple locally-optimized features rather than requiring uniform high precision throughout the entire component.
2Measurement precision
If multiple deformation sections with different characteristics are used in the driver element, then the limit torque precision is improved, but the device complexity increases
Solution Approach 1:
Multiple deformation sections with different geometric and material characteristics are merged into a single integrated driver element. This unified component engages with a corresponding deformation surface on the second component, combining the functions of multiple separate torque-limiting elements into one. The merging approach achieves high limit torque precision through the coordinated deformation of multiple sections while avoiding the assembly complexity of multiple separate components.
Solution Approach 2:
The driver element is designed to dynamically adapt its deformation characteristics based on the applied torque. As torque increases, different deformation sections engage sequentially, with each section deforming at a specific torque threshold determined by its geometric and material properties. This dynamic, progressive deformation mechanism allows the system to precisely specify the limit torque through the behavior of the deformation sections rather than relying on static, pre-set mechanical stops or springs.
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 approach allows for the precise specification and achievement of the desired limit torque, reducing the influence of manufacturing tolerances and enabling safe and controlled torque transmission in medical applications.
Implementation Method 1
at least one deformable driver element (20) is arranged or formed on the first component (14), that a deformation surface (22) interacting with the driver element (20) is arranged or formed on the second component (16), and that a distance (24) of the deformation surface (22) from the longitudinal axis (12) changes in the circumferential direction
Data Source
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AI summary
To improve a medical torque limiting device, which defines a longitudinal axis and comprises a first component and a second component, wherein the first component and the second component are designed to interact to transmit a torque acting on the first component to the second component such that, for a torque acting on the first component in a tightening direction which is less than a limit torque, the first component and the second component are not rotatable relative to each other about the longitudinal axis in the tightening direction, and for a torque acting on the first component in the tightening direction which is at least equal to the limit torque, the first component and the second component are rotatable relative to each other about the longitudinal axis in the tightening direction, so that it can be manufactured with high precision in a simple manner, it is proposed thatthat at least one deformable drive element is arranged or formed on the first component, that a deformation surface cooperating with the drive element is arranged or formed on the second component, and that the distance of the deformation surface from the longitudinal axis changes in the circumferential direction.