Wheelchair Foot Rest Latching for Side Release and Rigid Locking
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Solution Overview
Problem
Prior art foot rest assemblies for wheelchairs have limited accessibility for persons with limited mobility due to centrally positioned release levers and require multiple steps for loading, resulting in a loose and non-rigid latched position.
Innovation Solution
A latching mechanism with a laterally oriented release lever and a rocking pin that allows bi-directional rotation, enabling easy access and configuration to suit users, along with chamfered edges for improved rigidity and alignment, facilitating easy loading and secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the release lever is positioned centrally with respect to the frame members, then the lever is accessible from either side, but the lever becomes very difficult to operate for persons with limited mobility
Solution Approach 1:
The release lever is repositioned from a central location to a lateral position on the foot rest assembly, moving the interaction from a longitudinal dimension to a lateral dimension. This allows users to access and operate the lever from the side of the foot rest, providing better accessibility while maintaining ease of operation through a more ergonomic positioning that reduces the range of motion required.
2Ease of operation
If a sufficiently large tolerance is provided between the pin and hole for ease of insertion, then the pin can be easily inserted, but the resulting latched foot rest assembly remains loose and is not fully fixed and rigid
Solution Approach 1:
Chamfered edges are added to the pin and corresponding socket features as preliminary geometric preparations. These chamfers guide the pin into proper alignment with the socket during assembly, ensuring accurate positioning before the final latching engagement. This preliminary geometric action eliminates the need for large tolerances while maintaining ease of insertion through the guiding effect of the chamfers.
Solution Approach 2:
The pin and socket are designed with localized chamfered edges at specific interaction points. These localized geometric modifications provide precise alignment and rigid latching at the critical engagement zones, while the rest of the components maintain their structural integrity. The local quality enhancement ensures both ease of insertion through guidance and firm latching through precise fit.
3Adaptability or versatility
If multiple steps of sliding, twisting or rotating are required to load the foot rest assembly, then the assembly can be positioned, but the loading process becomes complex and time-consuming
Solution Approach 1:
The foot rest assembly is pre-configured with the latching mechanism and release lever in positions that enable direct attachment to the wheelchair frame. The connector features are designed with preliminary alignment elements that guide the assembly into the correct position during loading, eliminating the need for multiple sliding, twisting, or rotating steps. This preliminary configuration simplifies the loading process while maintaining full positioning capability.
Data Source
AI summary
A latching mechanism permits a swing-away foot rest assembly on a wheelchair to be selectively latched into a use position extending forwardly from the wheelchair. Mating connectors are provided on the foot rest assembly and the frame of the wheelchair which are movable relative to one another by a transverse rocking pin which rocks about an upright lever axis in two directions to permit the latching mechanism to be released by deflecting a release lever coupled to the rocking pin in either one of two opposing directions. The release lever can be coupled to the rocking pin in a plurality of different orientations in the use position to suit the user. Camming faces on the connectors automatically align and load the mating connectors into an engaged position when the foot rest assembly approaches the use position from any one of multiple different directions. The camming faces also permit the connectors to be mated with one another in a wedging action to improve rigidity of the foot rest assembly in the latched position.