Fixed pneumatic caster with PUR-foam tread and sheet steel hub

Pneumatic caster in a fixed bracket with PUR foam and sheet steel hub

This is a pneumatic caster in a fixed bracket with a tread in PUR foam and a hub in sheet steel, built for transport on uneven ground where you want the springy run of a pneumatic tire but no air pressure and no punctures. The tread is a cellular polyurethane with a hardness around 65 degrees Shore A. The foam is solid all the way through; it springs and damps like a pneumatic tire but can neither lose pressure nor be punctured by nails and sharp edges.

The behavior of the tread in operation is what separates it from an ordinary pneumatic tire. The PUR foam forms itself to smaller unevenness and takes up shocks, but since it is not air filled it needs no maintenance and does not bind at low pressure. The rolling resistance on a smooth floor is lower than on a pneumatic tire since the foam deforms less with every revolution, while the run stays softer than on a hard wheel. On really coarse terrain an air filled tire swallows large bumps better, but for normally uneven surfaces the foam gives a comfortable run without fuss.

A short comparison makes it clear. A hard solid wheel in nylon rolls most easily on a level floor and takes high point load, but damps nothing and is louder. A pneumatic tire damps the most but needs pressure checks and can be punctured. The PUR foam lies between: a soft and quiet run, no pump, no puncture.

The hub in sheet steel is pressed and stiff and holds the tread centered under load. The series comes with double ball bearings or a roller bearing. Double ball bearings spread the load over two rows of balls and give an even run under heavier weight, while a roller bearing takes up high radial load at the coarser dimensions. The load capacity reaches up to 120 kg per wheel, right for medium heavy carts and trolleys.

The wheels come in diameters from 260 to 400 mm. A larger diameter rolls more easily over thresholds and uneven ground and lowers the rolling resistance, while a smaller one keeps the overall height down. The wheel sits in a fixed bracket and rolls straight ahead, which gives good directional stability in fixed wheel positions on an underframe or at the front of a cart.

Where does it fit? Pneumatic casters with PUR foam and a steel hub sit under transport carts, tow trolleys, garden and material carts that are run both inside and out. The puncture free tread comes into its own where the wheel is exposed to spill, chips and sharp remains, and where downtime for a repaired puncture is not wanted.

Think about the operating environment. PUR foam is happiest at normal temperature and takes dry to slightly damp environments as well as most workshop oils and greases. It needs no pressure and cannot be punctured, but a soft cellular material wears faster than a hard wheel on long runs over coarse asphalt. Match the diameter to the surface and the tread lasts longer and the rolling resistance stays down.

Do you want to know which diameter and load capacity suits your cart and your surface? Get in touch and we will go through the load and the environment together.