Deployable Auxiliary Support Linkage for Wheelchair Terrain Stability
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Solution Overview
Problem
Wheeled apparatuses such as wheelchairs and strollers face difficulties in traversing uneven terrain due to small diameter front wheels and short wheelbases, leading to instability and poor steering.
Innovation Solution
An auxiliary support assembly with a mounting arrangement and linkage mechanism that allows an auxiliary wheel or ski to be deployed forwardly of the front wheels for increased stability and retracted when not in use, minimizing protrusion and maintaining maneuverability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an auxiliary wheel is added to increase wheelbase and improve stability on uneven terrain, then stability and terrain traversal capability are improved, but the device complexity and storage difficulty increase
Solution Approach 1:
The auxiliary support system is segmented into modular components: a mounting arrangement that attaches to the wheelchair frame, a linkage arrangement with movable links, and the auxiliary wheel assembly. This segmentation allows each component to be optimized independently and simplifies the overall system architecture, reducing complexity while maintaining stability benefits.
Solution Approach 2:
The linkage arrangement enables the auxiliary wheel to dynamically change position between a deployed configuration (protruding forward to increase wheelbase) and a retracted configuration (stored close to the wheelchair). This dynamic adaptability allows the system to provide stability only when needed, reducing the complexity burden during normal operation.
2Adaptability or versatility
If an auxiliary wheel assembly is permanently mounted to increase wheelbase, then terrain traversal capability is improved, but maneuverability and ease of storage worsen
Solution Approach 1:
The auxiliary wheel assembly transitions from a static permanent mount to a dynamic movable structure. The linkage arrangement with its movable links allows the auxiliary wheel to be positioned forward for terrain traversal and retracted for maneuverability, providing adaptability across different operating conditions without permanently compromising ease of operation.
Solution Approach 2:
The linkage arrangement is designed to automatically guide the auxiliary wheel through its deployment and retraction cycles using the motion of the wheelchair itself. As the wheelchair moves forward, the linkage naturally guides the auxiliary wheel into its retracted storage position without requiring active control, making the system self-managing and maintaining ease of operation.
3Ease of operation
If the auxiliary support protrudes forwardly when stored, then deployment is simplified, but the protruding distance increases making storage cumbersome
Solution Approach 1:
The linkage arrangement creates a dynamic storage configuration where the auxiliary wheel automatically assumes an optimal stored position that balances deployment simplicity with minimal protrusion. The movable links guide the auxiliary wheel to a compact retracted position that still allows easy access for deployment while minimizing the protruding distance to reduce storage space requirements.
Data Source
AI summary
An auxiliary support assembly for a wheeled apparatus, for example a wheelchair, includes a mounting arrangement for being fixed on the apparatus, an auxiliary support such as a wheel or ski, and a linkage arrangement supporting the auxiliary support to be movable relative to the apparatus between a deployed position supporting front wheels of the apparatus spaced above the ground and a stored position out of use with the front wheels on the ground. In one embodiment, the auxiliary support swings under the mounting arrangement between stored and working positions. In another embodiment, the auxiliary support is carried on a swing arm to be locked in a deployed position by a four bar linkage. In either embodiment, a first adjustment allows height and angular orientation of a steering axis of the deployed auxiliary support to be adjusted, while a second adjustment primarily adjusts the angular orientation of the steering axis.