Ball transfer units are omnidirectional load-bearing

spherical A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is the ce ...

ball A ball is a round object (usually spherical, but can sometimes be ovoid) with several uses. It is used in ball games, where the play of the game follows the state of the ball as it is hit, kicked or thrown by players. Balls can also be used f ...

s mounted inside a restraining fixture. They are identical in principle to a computer

trackball A trackball is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axes—like an upside-down ball mouse with an exposed protruding ball. Users roll the ball to position the on-s ...

(pointing device). Typically the design involves a single large ball supported by smaller ball bearings. They are commonly used in an inverted ball up position where objects are quickly moved across an array of units, known as a ball transfer table, a type of

conveyor system A conveyor system is a common piece of mechanical handling equipment that moves materials from one location to another. Conveyors are especially useful in applications involving the transport of heavy or bulky materials. Conveyor systems allow ...

. This permits manual transfer to and from machines and between different sections of another

. They are used in

airports An airport is an aerodrome with extended facilities, mostly for commercial air transport. Airports usually consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surface ...

for

luggage Baggage or luggage consists of bags, cases, and containers which hold a traveler's personal articles while the traveler is in transit. A modern traveler can be expected to have packages containing clothing, toiletries, small possessions, trip ...

delivery, or in industry as part of manufacturing systems. Prior to the invention of the ball transfer unit, first patented by Autoset Production Ltd in 1958, these applications were solved by the use of inverted

casters A caster (or castor) is an undriven wheel that is designed to be attached to the bottom of a larger object (the "vehicle") to enable that object to be moved. Casters are used in numerous applications, including shopping carts, office chairs, to ...

. However, casters recognise a trail, meaning that the wheels had to align before directional change could be achieved. Ball transfer units can also be used in a non-inverted ball down position as a type of caster, however this use is restricted by load-bearing limitations and the type of floor. Manufacturers have addressed this problem with ball transfer units incorporating

recirculating ball Recirculating ball, also known as recirculating ball and nut or worm and sector, is a steering mechanism commonly found in older automobiles, off-road vehicles, and some trucks. Most newer cars use the more economical rack and pinion steering ins ...

principles, however the inverted position is still the most common application and the least problematic.

References

Bulk material handling {{Industry-stub

See also

References