Tracked Chair Side Drive Assembly for Uneven Terrain Stability
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Solution Overview
Problem
Traditional wheelchair designs are unstable when traversing uneven terrain, limiting mobility for disabled individuals who wish to engage in outdoor activities on varied surfaces.
Innovation Solution
A tracked chair with a novel track geometry featuring a side drive assembly comprising a powered sprocket and independently pivoting forward and rearward non-powered bogey wheel sets, creating a non-isosceles triangular shape for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional wheelchair designs are used, then they are simple in structure and easy to manufacture, but they are unstable when traversing uneven terrain
Solution Approach 1:
The tracked chair divides the propulsion system into multiple independent segments: a powered sprocket, forward bogey wheels, rearward bogey wheels, and idler wheels. Each segment can independently pivot or adjust, allowing the track to conform to uneven terrain while maintaining stability. This segmentation enables the complex tracked design to adapt to rough surfaces without requiring a monolithic rigid structure.
Solution Approach 2:
The bogey wheels are designed to pivot independently on their axles, creating a dynamic suspension system that automatically adjusts to terrain variations. This dynamic capability allows the tracked chair to maintain stability on uneven surfaces by continuously adapting the wheel positions, transforming a static structure into an actively adapting system.
2Adaptability or versatility
If tracked chair designs are implemented, then mobility on uneven terrain is improved, but stability is reduced
Solution Approach 1:
The track geometry employs asymmetric positioning of the powered sprocket relative to the bogey wheels, creating a non-isosceles triangular configuration. This asymmetric design provides inherent stability by establishing a lower center of gravity and optimized weight distribution, preventing the tracked chair from tipping while maintaining the adaptability needed for varied terrain mobility.
Solution Approach 2:
The tracked chair adds a third dimension of movement by allowing bogey wheels to pivot vertically on their axles in addition to the horizontal track movement. This dimensional addition enables the system to simultaneously achieve mobility across uneven surfaces and maintain stability through vertical adjustment of wheel positions.
3Stability of the object's composition
If independently pivoting bogey wheels are used, then stability on uneven terrain is improved, but device complexity increases
Solution Approach 1:
The independently pivoting bogey wheels function as self-adjusting suspension elements that automatically respond to terrain variations without requiring external control systems or complex mechanisms. Each bogey wheel independently finds its own optimal position on the terrain, eliminating the need for sensors, actuators, or control electronics, thereby reducing overall system complexity while maintaining stability.
Data Source
AI summary
A tracked powered chair is described. A side drive assembly comprises a powered sprocket, a forward non-powered two wheel bogey, and a rearward non-powered two wheel bogey. Each bogey has a respective pivot member pivotally fastened at a first pivot member end between the first and second bogey wheels, and a second pivot member end fastened to the frame such that the forward and rearward bogey each pivot independently from one another around its respective pivot member. The geometry of the drive assembly creates a non-isosceles shaped triangular appearance (no two sides are of equal length).