Three Trade-Offs
If you’re looking for the truth about ergonomics a good way to start is with a definition: Ergonomics is the process of designing or arranging workplaces, products and systems so that they fit the people who use them.
As it relates to casters and wheels, ergonomics comes down to two factors. First, it’s is a matter of reducing push-pull force – or the amount of effort someone needs to expend in order to start or stop the movement of a piece of equipment. The second factor is maneuverability – how easily can that piece of equipment be turned.
Now, here’s the truth about ergonomic casters and wheels. To achieve ergonomic design, you will always have to sacrifice something – capacity, surface conditions or cost. Ultimately, it comes down to these three classic trade-offs.
Ergonomics vs Swivel Lead
The swivel lead is the distance between the vertical centre of the caster and the axle of the wheel. Increasing the swivel lead makes a caster easier to turn and improves maneuverability. The trade-off is that increasing the swivel lead decreases the capacity of the caster. In order to achieve ease of use, while protecting the cargo, you will have to increase the capacity and therefore the size of the caster – and that also means increasing your costs.
Ergonomics vs Wheel Specifications
There are situations where the only way to increase capacity is to increase the tread width of wheels. An example is when equipment has a fixed height requirement and that limits the overall height of the caster. Here’s the trade-off. More tread width creates more surface contact and more friction, increasing the push-pull force necessary to move equipment. Capacity comes at the expense of maneuverability.
The opposite example is crowned wheel treads that dramatically improve ease of operation because there is less wheel tread touching the floor. Again, what you gain in ergonomics you lose in capacity. And, the only other way to maintain capacity is to increase the size of the wheel, which increases costs.
Ergonomics vs Surface Conditions
The material used to make wheels has huge impact on the rollability of a caster. Steel wheels with their extraordinary hardness, have the least surface friction and are the easiest to move. At the same time, steel wheels are noisy and have a tendency to mark floors.
At the other extreme, rubber wheels are super soft, absorb shock, are very quiet and leave floors in pristine condition. That’s because there is more surface grip, but that comes at the expense of ergonomic casters. Unless the application or floor conditions dictate a particular tread material, the trick is to find a wheel that balances the protection of floors and the workplace environment with the best possible mobility.
In the end, you will make a better buying decision by understanding the trade-offs involved in finding the caster with an ergonomic profile that fits both your conditions and your budget.
For help choosing the caster that best meets your needs, contact your Algood Sales Rep or reach out to our customer service team by email service@algood.com or by phone at +1 (800) 254-6633.