Both manual material handling equipment, such as trolleys and hand jacks, and automated systems like AGVs and conveyors rely on wheels and castors to get the job done. These are the parts that ensure safe and timely movement and handling within commercial and industrial settings. They are built of different materials depending on the environments in which they’re used and the load capacities they are tasked to support and are offered in varying sizes.
Wheels vs Castors. What’s the Difference?
While wheels and castors are used interchangeably, there is a stark difference between the two. All of us are familiar with the cylindrical object with a central opening to fit an axle as a wheel, but castors are more complex. These not only include wheels, but also frames that hold the wheels in place as well as the mounting brackets that attach the whole rolling assembly to the rest of the material handling equipment. There’s a wide variety of both wheels and castors. And choosing the right replacement parts also impacts overall costs, especially in large-scale operations.
Types of Wheels Used in Industrial Handling Equipment
Choosing wheels for different industrial handling equipment boils down to the materials the wheels are made of, the flooring they’re to be used on, sizes and diameters, and the type of bearings they’re fitted with. This scope of variation lends to many types of wheels.
Materials
Wheels are offered in a range of materials, and often in a combination of different materials. The choice of materials is important when considering where and how the wheels are used, the loads that they need to carry, and the compatibility with different floor types. Some of the most common material handling equipment, such as carts and trolleys, will be fitted with rubber wheels. Here too this is some variety. Other wheels are optioned in polyurethane, nylon, glass-filled nylon, cast-iron, aluminium or come as pneumatic wheels.
Why Option Wheels in Rubber?
Wheels made of rubber are non-marking, meaning they don’t leave visible marks on floors, are shock absorbing and adjust to uneven surfaces or obstacles without affecting handling, and are extremely quiet so suitable for a range of settings. In addition, equipment rolling on rubber offer low rolling resistance on a range of different flooring, from timber, vinyl, carpet, tiles and even concrete floors. When compared to other materials, rubber offers long usage and requires little to no maintenance, meaning reduced downtime and handling costs.
Types of Rubber Wheels
Rebound Rubber Wheels – These are found in light to medium-duty equipment such as waste bins, laundry carts, trolleys used for electrical goods and appliances and gear for moving goods termed as ‘fragile’. Rebound wheels have high levels of cushioning and handle bumps and obstructions easily. In addition, they have very low rolling resistance and are quiet in operation.
Institutional Wheels – These are found on material handling equipment used in schools, hospitals, aged-care centres, offices and in some light industrial settings. They’re recognisable by their grey colour. Protection is enhanced with sealed bearings and nylon thread guards.
Anti-Static or Conductive Wheels – You’ll find this type of rubber wheels used in industries producing and handling electrical components and prevent electro-static discharges when transporting goods.
Other Options
Polyurethane is a popular material option. It is hard-wearing, can be used across multiple types of floors, has good chemical resistance, low rolling resistance and can be found in equipment used to transport extremely heavy loads.
Nylon wheels are ideal for hard and smooth surfaces such as tiles and concrete, both indoors and outdoors. They are very durable, resistant to corrosion and leave no marks. Typical uses are in the metal-working, chemical and automotive industries.
Cast iron wheels are resistant to temperature extremes, fare best against abrasions, and take the highest loads. The downsides are that they are quite noisy and can leave visible marks on softer flooring. This makes them more suitable for heavy-duty industrial environments.
Other less common wheel materials include aluminium and glass-filled nylon. The first has the best performance where temperatures can pose difficulties, such as in bakeries or refrigeration rooms. Aluminium is also good at handling heavy loads, second only to cast-iron wheels, but has the upper hand with virtually silent operation. Glass-filled nylon wheels are improved versions of regular nylon variants, with very good chemical resistance and higher strength. These too are used in settings with temperature extremes.
Specifying Wheels
Besides materials, wheels need to be the right size and optioned with bearings that make for easy yet safe handling.
Size matters in wheels as bigger wheels require less force to push loads and carts and trolleys can easily go over any obstacles or bumps. In addition, they provide better cushioning, so fewer vibrations. Larger wheels are safer, speed up workflow, can carry heavier loads and aren’t necessarily more expensive. Common sizes in most rebound rubber wheels are 75, 100, 125, 150 and 200mm.
Bearings affect factors like rolling resistance, durability and load-carrying capacity. Most widespread are sealed ball bearings with very low rolling resistance, high durability and low maintenance needs. This makes wheels with these bearings ideal in medium to heavy-duty applications. Other variants are roller bearings, good for slow-moving, high impact and heavy-duty settings with very heavy loads. Similar are wheels fitted with taper roller bearings. These have some of the highest loading capacities. Other material handling equipment can have plain bronze bearings, especially if there’s the need to move items in areas with high corrosion, chemicals and heat.
