5.6 CHOOSING THE WHEEL
Each of the parameters and operating characteristics outlined in the previous paragraphs is used in one of the three steps involved in choosing the wheel.
The type of wheel suitable for the floor and operating environment is identified in step 1. The following graph summarizes the factors that influence the choosing of the type of wheel; “type of wheel” means:
- materials that form the covering and the wheel centre body;
- type of anchorage between covering and wheel centre body;
- rolling actions.
The load capacity, static load and smoothness values required by the specific application and needed to determine the wheel diameter are calculated in step two.
One of the most important parts of this step is an analysis of the load that the wheel must support. The following diagram indicates what calculations to perform and what values to consider depending on the various operating conditions. These aspects must always be indicated (magnitude and nature of the load and speed), while ensuring that all the values determined are not higher than the rated values indicated in the manufacturer’s catalogue. If the evaluation of various aspects generates different data with reference to the same wheel characteristic, the final choice must be made based on the most conservative condition.
The correct castor is chosen in the third step. The step can be divided into two separate parts:
- Choosing fixed or swivel brackets, depending on manoeuvrability and directionality needs;
- Checking the compatibility between dynamic load capacity and rated dynamic load capacity of the wheel and bracket.
The following table summarizes some general indications for choosing the right wheels according to the application’s features.