Jamming Roller Lock With Passive One-Way Locking Force
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Solution Overview
Problem
Existing jamming roller locks in orthopedic devices often require continuous power to maintain locking force, are not cost-effective, and lack flexibility in directional locking, which is inefficient and energy-intensive.
Innovation Solution
A jamming roller lock design featuring a housing with clamping discs that have recesses for jamming rollers, allowing for adjustable locking force through the number of recesses and rollers, enabling free rotation in one direction while locking in the opposite, using a freewheel and locking side configuration to manage rotation without external resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a wrap spring lock is used to achieve locking of the drive train against external forces, then locking force is provided, but continuous power is required to maintain the locking force
Solution Approach 1:
The jamming roller lock utilizes the external force itself to trigger the locking mechanism. When an external force attempts to rotate the driven side, the jamming rollers automatically engage with the housing to block rotation. The system serves itself by using the attempted movement to activate the locking action, eliminating the need for continuous power supply to maintain locking force.
Solution Approach 2:
The patent replaces the active mechanical system (wrap spring lock requiring continuous power) with a passive mechanical system (jamming roller lock that locks automatically upon attempted rotation). The substitution transforms an energy-consuming active locking mechanism into an energy-free passive locking mechanism that responds automatically to external forces.
2Adaptability or versatility
If a jamming roller lock is designed to lock in one direction, then directional locking is achieved, but the drive train cannot operate freely on the motor side
Solution Approach 1:
The clamping discs are designed with asymmetric recesses that have different geometries on opposite sides. One side of each recess is configured to allow jamming rollers to engage with the housing for locking, while the opposite side is configured to allow free movement. This local differentiation in the recess geometry enables directional locking while maintaining free rotation in the opposite direction.
Solution Approach 2:
The jamming roller lock employs asymmetric clamping disc design where the recesses are not symmetric about the center. The recesses are positioned and dimensioned such that they provide locking engagement in one rotational direction but allow free movement in the opposite direction. This asymmetry is fundamental to achieving the bidirectional functionality of free rotation in one direction and locking in the other.
3Force
If the number of jamming rollers is increased to scale locking force, then locking force is enhanced, but device complexity increases
Solution Approach 1:
The locking mechanism is segmented into multiple identical clamping discs, each containing one or more recesses and working with individual jamming rollers. This segmentation allows the locking force to be scaled by simply adding more identical modular units rather than redesigning the entire system. Each clamping disc assembly functions independently, and their effects accumulate to provide the total locking force required.
Solution Approach 2:
The locking force is scaled by changing the parameter of the number of jamming rollers and recesses rather than by increasing the size or complexity of individual components. The patent allows for arbitrary scaling of locking force through parameter adjustment (number of rollers) while maintaining the same basic design geometry, thus avoiding proportional increases in overall device complexity.
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 allows for energy-efficient directional locking and unlocking, scalable locking force, and reduced component complexity, ensuring smooth operation with electric motors while maintaining locking without continuous power, enhancing the functionality and cost-effectiveness of orthopedic devices.
Implementation Method 1
a frictional connection of a fixed housing. This frictional connection creates the desired locking effect.
Data Source
AI summary
A jamming roller lock with a housing and at least two jamming discs, which are arranged in the housing such that they can be rotated and which each comprise at least one recess, in which a jamming roller is located, at least one driving projection and at least one driven projection, wherein the jamming discs are arranged and designed in such a way that a rotation of the jamming discs can be achieved by driving the driving projections and a rotation of the jamming discs is prevented by driving the driven projections.