Caster Wheel Arrangement with Assist Wheels for Surface Transitions
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Solution Overview
Problem
Caster wheels face challenges in navigating transitions between surfaces with gaps and rises, as increasing wheel diameter to overcome these obstacles increases force and rotational inertia, reducing maneuverability, and may require redesigns for existing products.
Innovation Solution
Incorporating assist arrangements with leading and trailing wheels of smaller diameters, strategically positioned to minimize resistive forces and maintain maneuverability, allowing the primary wheels to navigate surface transitions with reduced effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wheel diameter is increased to overcome gaps and rises, then the ability to traverse surface transitions is improved, but the force required to push the wheel forward increases
Solution Approach 1:
The wheel system is segmented into a leading wheel and trailing wheel that work together with the main caster wheel. The leading wheel (smaller diameter) contacts the far surface first and prevents the main wheel from sinking into the gap, while the trailing wheel provides additional support. This segmentation allows the system to overcome gaps and rises without requiring an excessively large main wheel, thereby reducing the force needed compared to a single large wheel design.
2Reliability
If the wheel diameter is increased to overcome gaps and rises, then the ability to traverse surface transitions is improved, but the turn radius and rotational inertia increase, reducing maneuverability
Solution Approach 1:
By segmenting the wheel system into multiple wheels of different sizes (leading wheel with smaller diameter, trailing wheel with smaller diameter, and main caster wheel), the overall turn radius is reduced compared to a single large wheel design. The smaller leading and trailing wheels have lower rotational inertia, making the system more maneuverable while still providing the capability to traverse gaps and rises through their coordinated action.
3Reliability
If the wheel diameter is increased to overcome gaps and rises, then the ability to traverse surface transitions is improved, but product redesign is required
Solution Approach 1:
The wheel assembly is segmented into modular components (leading wheel assembly, main caster wheel, trailing wheel assembly) that can be independently designed and manufactured. This modular segmentation allows the assist wheels to be added as an enhancement to existing caster designs without requiring complete redesign of the entire product, facilitating easier integration into existing product lines.
4Reliability
If the wheel diameter is increased to overcome gaps and rises, then the ability to traverse surface transitions is improved, but the weight of the wheel increases
Solution Approach 1:
The wheel system is segmented into multiple wheels where the main caster wheel can maintain a moderate, optimized size for normal operation, while the leading and trailing assist wheels are smaller and only engage when needed for traversing gaps and rises. This segmentation allows the system to achieve gap-crossing capability without requiring the main wheel to be excessively large and heavy, thereby reducing overall wheel system weight compared to a single large wheel design.
Data Source
AI summary
A caster wheel arrangement includes a base; a yoke rotatably mounted to the base via a kingpin; at least a first caster wheel rotatably mounted to the yoke; and an assist arrangement moveably mounted to the yoke. The assist arrangement facilitates travel of the caster wheel arrangement over a surface transition (e.g., a gap, a rise, etc.). Non-limiting example assist arrangements include a leading wheel, a leading variable radius wheel, a trailing wheel, a step member, and combinations thereof.