Flexural Torque Limiter with Disengaging Spokes
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Solution Overview
Problem
Current torque limiting mechanisms for mechanical joints are often bulky, expensive, and require manual intervention, and they do not effectively disengage load when excess torque is applied, potentially damaging the device.
Innovation Solution
A torque limiting system using flexural axial spokes with teeth that engage and disengage from grooves on a cylindrical member when torque exceeds a threshold, allowing independent rotation and reducing stress on mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction-based mechanisms or ball bearings in detents are used to limit torque, then torque limiting function is achieved, but device complexity and bulk increase
Solution Approach 1:
The torque limiter is divided into discrete modular components: a first cylindrical member with grooves, a second cylindrical member with flexural spokes and teeth, and optional third/fourth members. This segmentation allows the system to achieve torque limiting functionality while reducing overall complexity through standardized, interchangeable parts that can be manufactured independently and assembled systematically.
Solution Approach 2:
The flexural spokes are designed as flexible elastic elements that can bend and deform under torque load. These thin, flexible structures replace bulky mechanical components like ball bearings and friction plates, achieving the same torque limiting function with significantly reduced complexity and size. The flexural spokes engage and disengage smoothly through elastic deformation rather than requiring multiple discrete mechanical parts.
2Reliability
If breakable pins or friction mechanisms are used, then torque limiting is achieved, but manual intervention is required to re-engage the load
Solution Approach 1:
The torque limiter is designed to automatically re-engage after disengaging under excessive torque. When the load is removed or reduced, the flexural spokes naturally return to their engaged position through elastic recovery, allowing the system to resume normal operation without manual intervention. This self-service capability eliminates the need for operators to manually reset breakable pins or re-engage friction mechanisms.
Solution Approach 2:
The system transitions dynamically between engaged and disengaged states based on the applied torque. The flexural spokes continuously adjust their position according to the load conditions, automatically moving from the engaged state during normal operation to the disengaged state when torque exceeds the threshold, and back to engaged when the threat is removed. This dynamic behavior eliminates static, manual-reset requirements.
3Reliability
If traditional torque limiting mechanisms are used, then torque protection is provided, but the mechanisms are bulky and expensive
Solution Approach 1:
The flexural spokes are implemented as thin, flexible elastic elements rather than bulky mechanical components. These slender spokes provide the necessary torque limiting function while occupying minimal space and having low weight. The elastic deformation of these thin structures replaces the need for large friction plates, heavy ball bearings, or robust breakable pin assemblies, achieving protection with minimal mass.
Solution Approach 2:
The system utilizes elastic materials for the flexural spokes that combine flexibility with sufficient strength. This material selection allows the creation of lightweight yet durable components that can withstand repeated engagement and disengagement cycles. The composite approach of using elastic materials instead of traditional metallic mechanical parts reduces both weight and manufacturing cost while maintaining protective functionality.
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 system effectively limits torque by disengaging when a threshold is reached, preventing damage to mechanical components and allowing for efficient energy transfer while being adaptable to various applications with adjustable torque thresholds.
Implementation Method 1
The second cylindrical member can include flexural spokes with teeth that engage the grooves along the first cylindrical member when no torque is applied and that disengage from the grooves when a torque that exceeds a threshold torque is applied
Data Source
AI summary
In example embodiments, a discrete torque limiter is described that includes a first cylindrical member including grooves along a longitudinal surface of the first cylindrical member. The discrete torque limiter includes a second cylindrical member arranged concentrically with the first cylindrical member. The second cylindrical member can be adapted to move independently around the first cylindrical member. The second cylindrical member can include flexural spokes with teeth that engage the grooves along the first cylindrical member when no torque is applied and that disengage from the grooves when a torque that exceeds a threshold torque is applied to the first cylindrical member or second cylindrical member.