Torque Limiter With Inclined Plane Guide For Surgical Instruments
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Solution Overview
Problem
Existing surgical torque limiters rely on elastic bodies that determine maximum torque and are prone to property changes due to material fatigue, limiting adaptability and reliability in transmitting different torques.
Innovation Solution
A torque limiter design featuring an inclined plane guide for rolling bodies, with adjustable side walls and pressure-exerting elements, allowing for customizable maximum torque transmission in one direction and increased torque in the opposite direction, ensuring consistent mechanical properties over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastic body is used to transmit torque, then torque transmission is enabled, but the maximum torque is limited by the elastic body properties and these properties change over time due to material fatigue
Solution Approach 1:
The patent changes the fundamental parameter from elastic deformation to rigid body mechanics with rolling elements. The maximum transmissible torque is determined by the number and arrangement of rolling bodies rather than material elasticity, allowing predictable torque values without material fatigue effects.
Solution Approach 2:
The patent replaces the elastic body mechanical system with a rolling body mechanism. Instead of relying on elastic deformation and material properties, the system uses rolling elements that engage with inclined planes to transmit torque, eliminating material fatigue concerns.
2Device complexity
If the same torque limiter design is used for both tightening and loosening, then structural simplicity is maintained, but the ability to loosen seized screws is compromised
Solution Approach 1:
The patent introduces asymmetric inclined planes with different angles for the two rolling bodies. One inclined plane has a smaller angle for efficient torque transmission during tightening, while the other has a larger angle that provides mechanical advantage for loosening seized screws, creating directional asymmetry in the mechanism.
Solution Approach 2:
The patent makes the rolling bodies movable within the cage rather than fixed. This dynamic arrangement allows the rolling bodies to shift positions based on rotation direction, enabling the mechanism to adapt its torque transmission characteristics for both tightening and loosening operations.
3Adaptability or versatility
If rolling bodies are held in a cage with inclined plane guide, then maximum torque can be set by choosing the number of rolling bodies, but the structure becomes more complex
Solution Approach 1:
The patent divides the torque transmission function into discrete rolling bodies that can be individually selected and arranged. By segmenting the torque transmission into multiple independent rolling elements, the system allows customization of maximum torque by simply changing the number or arrangement of these modular components.
Solution Approach 2:
The patent introduces a cage as an intermediary structure that holds and guides the rolling bodies. This intermediary component simplifies the overall design by providing a standardized framework that accommodates different numbers and types of rolling bodies, making torque customization easier despite the added structural element.
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 control of torque transmission, allowing for easy loosening of seized screws with significantly higher torque than the maximum screwing torque, while maintaining consistent mechanical properties and facilitating sterilization.
Implementation Method 1
at least one rolling body (6) which is held in a rolling body holder (7) of the cage (8) and can roll along a guide in the form of an inclined plane (14, 15)
Implementation Method 2
a certain resistance to displacements of the rolling body along the oblique plane can be achieved by choosing the angular position of the inclination
Data Source
AI summary
A torque limiter, in particular for a surgical instrument, comprises a rotor (4) and a cage (8) arranged coaxially in relation to the rotor (4), the cage has at least one rolling body holder (7) with a rolling body (6) held in it, the rolling body holder (7) has at least one side wall which is arranged at an oblique angle relative to a circumferential direction of the cage (8).