Ball casters – Technical Service

Ball casters / ball units are suitable for transporting products and goods for which it is necessary to have the option of horizontal movement in all directions as well as rotation around the vertical axis. They ensure the low-friction, heavy-duty transportation of materials. They also enable rapid changes of direction. Ball casters are characterised by a high degree of temperature resistance and shock resistance.

The use of a variety of materials makes possible a wide variety of uses for the ball casters. They are therefore used not only in conveyance technology but also in machine and plant construction, in medical technology and further industrial sectors.

Structure

Our Schulz ball casters / ball units consist of a steel or sheet steel casing with an embedded or integrated ball cup. This contains a large number of support balls, which enable the low-friction rotation of the bearing ball in all directions. While in motion, the support balls roll about in the ball cup. The construction of our ball casters ensure maximum load-bearing capacity and an even rolling motion at each installation position (in a few exceptional cases, the load limit is reduced in the case of overhead installation). Most ball casters have a drain hole.

Materials

The casing, top cover, bearing shells and all other built-in parts are made of steel. The casing and top cover are galvanised or gunmetal-finished´.
The standard programmes of some designs also include ball casters made entirely of non-corroding steel (1.4301).
All the built-in parts on which the balls move are tempered (except for ball casters with countersunk sheet steel casing). In standard models, tempered balls of rolling bearing steel (1.3505) or non-corroding steel (1.4034) are used. In addition, it is also possible to use plastic bearing balls (POM) for transportation materials with sensitive surfaces. Other materials (PTFE, ceramic…) can be used for special applications.

Loading

To calculate the load for a ball caster, the weight of the object to be transported is divided by 3. The result gives the maximum dynamic load for a ball caster. In particular, the stability of the base of the object to be transported will affect this value. In the case of structural unevenness, the service life of the ball caster can be heavily reduced through being subjected to excessive stress in the form of constant shocks (lateral jolting of the load). In practice, depending on the stability of the object to be transported, considerably more ball casters will need to be deployed than indicated by the theoretical load-bearing capacity calculation.

Spacing

The interval between the ball casters is calculated by dividing the smallest base measurement of the object to be transported by 3.5. This ensures that at least 3 ball casters in the x and y axis are always bearing the load. This prevents the load from overturning or tilting.

Conveyance velocity

Depending on the construction type of the ball caster / ball units, we recommend conveyance speeds of 1-2 m/s. Higher speeds of up to twice that velocity are possible over short periods.

Temperature range

Ball casters / ball units with steel balls can be deployed in a temperature range of -30°C to +100°C. Ball casters with plastic balls can be deployed at temperatures up to +30°C. At higher temperatures, it is necessary to make constructional changes to the ball casters and to allow for a reduced dynamic load. In addition, at temperatures of over 50°C the felt sealing ring should be dispensed with.

Lubrication

Ball casters / ball units are given lifetime lubrication at our works, and are additionally equipped with an oil-soaked felt seal which reduces the accumulation of dirt. No additional lubrication is necessary, as the bearing ball can be oiled subsequently. For this case we recommend plus6 Multispray (82410)!