Rotary Locking Bearing for Wheelchair Caster Tip Control
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Solution Overview
Problem
Existing wheelchair suspension systems face challenges in selectively controlling caster arm movement in response to fore/aft tipping movements, with existing mechanisms being bulky or limited in directional control and difficult to package.
Innovation Solution
A selectively locking rotational bearing element with an outer race and locking members, actuated by a sensor, to restrict or permit movement of a caster arm relative to a wheelchair frame, using sprag elements or pawls to engage and disengage with the outer race.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional pin tumbler lock mechanism is used, then the lock structure is simple and easy to manufacture, but the lock is vulnerable to picking attacks and lacks security features
Solution Approach 1:
The locking mechanism is divided into multiple independent segments including a rotating locking member with multiple locking elements, each capable of independent movement. This segmentation allows the lock to resist picking attacks while maintaining a relatively simple overall structure that can be manufactured using conventional processes.
Solution Approach 2:
The locking member is designed to rotate between locked and unlocked positions, transforming the static pin tumbler mechanism into a dynamic system. This rotational movement provides enhanced security against picking while the mechanism remains simple enough for conventional manufacturing.
2Reliability
If a complex locking mechanism with multiple components is implemented, then security against picking attacks is improved, but the manufacturing cost and complexity increase
Solution Approach 1:
Multiple locking elements are combined into a single rotating locking member, reducing the number of separate components that need to be manufactured and assembled. This merging approach maintains high security against picking attacks while simplifying the manufacturing process and reducing production costs.
Solution Approach 2:
The rotating locking member performs multiple functions simultaneously: it engages multiple locking elements, provides rotational movement for locking/unlocking, and resists picking attacks through its dynamic configuration. This multi-functionality reduces the need for additional specialized components, easing manufacturing.
3Reliability
If a locking mechanism requiring multiple操作步骤 is used, then security is enhanced, but the ease of operation decreases
Solution Approach 1:
The locking mechanism uses dynamic rotational movement of a single locking member to achieve secure locking and unlocking with minimal user input. This dynamic approach enhances security while maintaining ease of operation, as users only need to rotate the key or actuator a short distance.
Solution Approach 2:
The rotating locking member automatically engages and disengages multiple locking elements through its rotational movement, eliminating the need for users to manually manipulate multiple separate components. This self-service mechanism enhances security while simplifying the user operation to a single rotational action.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A selectively locking rotational bearing element includes at least one bearing element supporting an outer race for rotational movement and a plurality of locking elements disposed circumferentially about an inner surface of the outer race. An actuator selectively moves the plurality of locking elements into engagement with the outer race to restrict rotational movement of the outer race and selectively move the plurality of locking elements away from engagement with the outer race such that the outer race is free to rotate relative to the locking elements.