Evolving industrial requirements mean that trolleys and machines are required to carry heavy loads ever more frequently.
Handling – invariably mechanical – of such machines and trolleys, calls for the use of wheels specifically designed for the purpose.
A brief overview of the main types of wheels can help companies choose the most suitable wheels for different application conditions.
Wheels for loads above 500 kg: risks associated with incorrect choices
Handling of trolleys with total loads greater than 500 kg results is linked with specific requirements.
In these conditions, it becomes particularly important to choose the right wheel: possible incorrect choices can lead to breakage of the application on which the industrial wheels are mounted, an event that, in the case of heavy loads, can lead to shut-downs of production lines, operator fatigue, and safety hazards in the workplace.
Wheels for heavy loads: factors to consider
As in the case of all other wheel types, also when choosing wheels to handle heavy loads it is essential to consider factors related to the floor surface, operating environment, and type of load to be handled.
For high loads it also becomes especially important to assess the speed of use and the traction means employed to move the wheel-mounted application.
Static carrying capacity and speed factor for heavy load handling
Static carrying capacity
The speed at which the application must be handled is a decisive factor when choosing the right wheel.
If speed is null and hence the application is primarily static, it is sufficient to compare the necessary load of each wheel with the static carrying capacity.
In these cases the best choice would be polyamide wheels for high loads or metal wheels (steel or cast iron).
Different load handling methods
If the speed is different from 0 and the application is designed to move frequently, the means of traction employed must be evaluated: manual handling, towed mechanical movement, or on-board mechanical movement.
Manual handling refers to cases when the effort is applied by one or more people and the trolley speed is generally less or equal to than 4 km/h.
Conversely, handling is mechanical when the effort is applied by a mechanical means and the speed is above 4 km/h.
Manual handling of heavy loads
In the case of manual load handling the key factor to consider is rolling resistance.
Technically speaking, rolling resistance is the value (expressed in daN) of the maximum load that can be supported by each wheel at a constant speed of 4 km/h when applying traction/thrust effort of 5 daN (not considering the initial pickup). This value is obtained by applying a traction effort of 20 daN to a 4-wheel trolley and then measuring the maximum transportable load per wheel during travel in steady state conditions.
The applied tractive force of 20 daN is recognised as the limit of human fatigue that can be tolerated for extended periods of time.
In general, the lower the rolling resistance of a wheel, the less effort is required for the operator to move the trolley and hence the more ergonomic the trolley.
Important: the rolling resistance value approximates the handling effort at constant speed. The effort required to move a trolley from a standstill is greater. To reduce starting effort, use wheels with an ergonomic round profile.
Mechanical handling of heavy loads at speeds below 12 km/h
In the case of mechanical handling, use exclusively wheels with polyurethane covering and hub with ball bearings. Also, for handling speeds of more than 6 km/h, use exclusively wheels with a metal centre (aluminium, cast iron or steel), thus excluding wheels with plastic centres.
Mechanical handling of heavy loads at speeds above 12 km/h
In the case of speeds above 12 km/h, wheels with an extra-thick covering in elastic polyurethane or Vulkollan® are highly recommended.
In all cases of mechanical handling it is also especially important to assess the right bracket to combine with the wheels, because not all brackets are capable of withstanding the impacts and stresses associated with high speed handling.
In the case of speeds above 16 km/h, contact the wheels manufacturer directly for specific technical advice.
To find the most suitable industrial wheels in relation to different application needs, refer to the following detailed guide: https://www.tellurerota.com/en/industrial-wheels-perfect-answers-every-requirement