Torque-Limiting Spindle With Self-Resetting Clutch for Locksets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing locksets are susceptible to over-torqueing attacks, which can damage the handle and internal components, and current torque-limiting mechanisms, such as frangible elements and traditional slip clutches, have drawbacks like requiring replacement or being complex and difficult to reset.
Innovation Solution
A torque-limiting spindle with an input member, output member, clutch mechanism, and bias mechanism that engages the handle and hub, limiting torque transmission to a threshold value and allowing discrete rotational positions to prevent excessive torque from being applied to the hub, thereby protecting the lockset components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frangible element is used to limit torque, then excessive torque is prevented from damaging components, but the element must be replaced after breaking
Solution Approach 1:
The torque-limiting mechanism is designed to be self-resetting through the spring-loaded clutch mechanism. When excessive torque is applied, the clutch disengages to prevent damage, and automatically re-engages when torque is reduced, eliminating the need for manual replacement or intervention. This self-service capability resolves the contradiction by maintaining reliability while eliminating repair requirements.
2Reliability
If a traditional slip clutch is used to limit torque, then excessive torque is prevented, but the mechanism becomes complex with multiple parts
Solution Approach 1:
The patent combines the torque-limiting function and the reset mechanism into a single integrated clutch assembly. The spring-loaded clutch mechanism performs both torque limitation and automatic resetting functions, eliminating the need for separate complex mechanisms. This merging reduces device complexity while maintaining the reliability of torque protection.
3Reliability
If a traditional slip clutch is used, then torque limitation is achieved, but returning the handle to desired orientation becomes difficult
Solution Approach 1:
The clutch mechanism is designed with dynamic characteristics that allow it to engage and disengage based on torque conditions. When excessive torque is applied, the clutch disengages, allowing the handle to rotate freely to a new position. When torque is reduced, the spring automatically re-engages the clutch, securing the handle in its new position. This dynamic behavior enables easy handle repositioning while maintaining torque protection.
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 solution effectively prevents damage from over-torqueing by allowing torque transmission only up to a threshold, enabling the lockset to maintain functionality and allowing easy return to the desired handle orientation after excessive torque application.
Implementation Method 1
The bias mechanism is engaged with the input member and the output member and exerts a biasing force urging the first engagement feature and the second engagement feature into engagement with one another
Data Source
AI summary
An exemplary torque-limiting spindle includes an input member, an output member, a clutch mechanism, and a bias mechanism. The input member extends along a longitudinal axis, is configured for connection with a handle, and includes a first engagement feature. The output member extends along the longitudinal axis, is configured for connection with a rotatable member of a lockset, and includes a second engagement feature. The clutch mechanism includes the first engagement feature and the second engagement feature. The bias mechanism is engaged with the input member and the output member and exerts a biasing force urging the first engagement feature and the second engagement feature into engagement with one another.