There are many factors that go into improving industrial caster ergonomics. It starts with the push/pull rating that you are looking for based on these factors.
Push/pull factors include the wheel size, the material used to make the wheel, the length of the swivel lead and the wheel bearings.
For reducing push force, increasing wheel size will improve caster ergonomics to a point, but each application has its own unique sweet spot. Our Caster Concepts engineering group has the scientific tools to test push/pull ratings. This testing is important because human push/pull testing can change each time someone else does the pushing or pulling.
In theory, to get the best ergonomics at every opportunity means increasing wheel diameter (for example to 12 inches). You also need to go with a smaller width (for example 1.5 inches). The result is a smaller footprint and reduced push-pull force. But many carts have size limitations on the wheels that they can accommodate. So then we have to look at other features that improve ergonomics.
Tire material on a wheel can improve ergonomics. Our extensive testing has proven that a tear-resistant material like our 85A or 95A T/R material can improve push/pull ratings when limited to smaller diameter wheels.
We have also tested various swivel leads with smaller diameter wheels. Findings show that going to a longer swivel lead also decreases push/pull rating because increasing the swivel lead makes the cart easier to turn.
Swivel sections can also have an impact on ergonomics. Traditional kingpin swivel casters carry the load on the kingpin which can cause spikes in push/pull force. On kingpinless swivel casters, the load is concentrated on the ball bearings and since the bearings float freely in the raceway it can cause some spikes in push/pull but less than a kingpin caster. With maintenance-free swivels, the load is concentrated on the thrust bearing which allows the load to disperse and reduce push/pull.
Caster Concepts offers a line of maintenance-free casters that help improve ergonomics. These casters have a precision ball bearing in the swivel section that does not require the maintenance of swivel sections with standard ball bearings.
Another way to improve ergonomics is to choose a caster with precision bearings that are sealed and maintenance-free. Bearings that require maintenance can become dirty or contaminated with debris. If these bearings are not properly maintained the lubricant can break down if not properly maintained which can, in turn, cause the rolling resistance can quickly increase.
Please feel free to contact me at firstname.lastname@example.org for any further industrial caster questions.