The Casters are often an unnoticed component in a mobile piece of machinery, since it is usual to evaluate the Machine by its own functions. But mobility is often one of the critical features of equipment, and defines its portability. Portability, and the property of wheeling down the equipment to the desired application spot, is often the main selling point. But the designs of the Casters are, like so many components of a total design, not in the hands of the Equipment Designer. The Designer these days simply consults a detailed catalogue and datasheets from the component selects the component based on the information given in the datasheets. Manufacturer and Casters are generally bought out packages, and so equipment Designers think they need not bother about the Casters overmuch. But sometimes their design for a mobile machine hinges on the performance of this most neglected component. And not this package, but the Heavy Duty Caster Wheels, which are perhaps the least considered portion of the Caster Assembly.
The Wheels have the most onerous duty. It carries, not just the total Caster Assembly, but the complete Machine itself. Yet its design, manufacture and even testing are left in the hands of a third party. It is therefore advised that the Wheel mechanism and construction is carefully analyzed by the overall designer of the equipment, and sufficient Factor of Safety taken so that its load capacity can exceed all contingencies.
In the modern scene, the Wheels are naturally Cast Polyurethane (Green), which is resistant to Hydrolysis, and Oil, and also causes less pollution underground. It has less marking ability on the ground and holds its Cast shape even under great pressure. Durability and longevity are built in. the Wheel Core is made of aluminium, which does not rust easily, and also increases the longevity of the Wheel. The Frame of the Wheel is so constructed that it does not buckle easily, and the Cast Polyurethane of the Wheel ensures shape holding over a long period of time.
These days, Heavy Duty Caster Wheels bear loads anywhere from 350 kilograms to a few thousand kilograms. These Heavy Duty Wheels in their highest range often use interstitial materials developed from Space Exploration, and this technology has been tried and tested in, for example, the Moon Buggy. Finally it seems, that light has dawned on the Designers of mobile equipment, and they are busy rendering the whole equipment safe and workable.