Locking Pivot for Wheelchair Armrests
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Solution Overview
Problem
Existing wheelchair components lack a reliable and versatile mechanism for controlling the relative motion between armrests and wheelchair structures, limiting user flexibility and safety.
Innovation Solution
A locking pivot device that allows controlled motion between armrests and wheelchair structures, featuring a shuttle, base, stop ring, pivot cap, and detent spring, enabling 360° movement with adjustable limits and reversible locking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is added to control armrest movement, then safety and stability are improved, but device complexity increases
Solution Approach 1:
The locking pivot device automatically locks when the armrest reaches a predetermined position through the interaction of the shuttle, detent spring, and stop ring, eliminating the need for separate control mechanisms. The system self-regulates movement limits without requiring additional actuators or control systems.
Solution Approach 2:
Multiple functional components (shuttle, detent spring, stop ring, pivot cap) are nested within a compact housing structure, allowing the locking mechanism to be integrated into the existing armrest assembly without requiring separate external components or increasing overall device footprint.
2Adaptability or versatility
If 360° movement capability is provided, then user flexibility is improved, but control over motion limits becomes more difficult
Solution Approach 1:
The locking pivot device allows dynamic adjustment of motion limits by repositioning the stop ring around the pivot axis, enabling users to customize the range of motion according to different usage scenarios while maintaining full 360° capability when needed.
Solution Approach 2:
The stop ring is designed as a separate, adjustable component that can be independently positioned to define different motion limits, allowing the system to segment the full 360° range into controlled portions based on user needs.
3Adaptability or versatility
If a reversible locking mechanism is implemented, then adaptability to different user needs is improved, but manufacturing complexity increases
Solution Approach 1:
The detent spring and shuttle locking mechanism are extracted as separate, modular components that can be independently manufactured and assembled, simplifying production while enabling reversible locking functionality through straightforward mechanical interactions.
4Reliability
If multiple components (shuttle, base, stop ring, pivot cap, detent spring) are used, then reliability of locking is improved, but device complexity increases
Solution Approach 1:
The base and pivot cap are merged into a single integrated component that provides both structural support and pivot functionality, reducing the total component count while maintaining the reliability of the locking mechanism through the combined structural integrity.
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
Enhances user flexibility and safety by allowing adjustable armrest movement and secure locking, accommodating user preferences and situational needs through reversible locking configurations.
Implementation Method 1
a detent spring positioned within the base and configured to bias the shuttle between a retracted position and an extended position
Data Source
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AI summary
A locking pivot device can include a base, a stop ring, and a shuttle. The stop ring can be supported within the base. The stop ring can include stops formed by an inset in an inner perimeter of the stop ring. The stop ring can also include teeth formed in a different portion of the inner perimeter from the stops. The shuttle can be received in the base. The shuttle can include at least one tooth selectively engageable with the teeth of the stop ring to selectively lock the stop ring at different positions. The shuttle can further include lateral surfaces engageable with the stops to define a predetermined range of motion of the stop ring within the base.