Types of extraction, size, low degree of bending, high load capacities, resistance to shocks and vibrations: these are often the primary criteria guiding a designer in their choice of a telescopic rail for an application.
But in certain use cases, the first question to be asked could be a different one altogether.
Telescopic rails made from steel or aluminium are used in a wide range of settings, from industrial automation in fields such as intralogistics or packaging to sectors such as railway or aircraft interiors – where manual extraction is more common – and even food & beverage or vending machines, and they are usually classified primarily based on the type of extraction they can offer:
- Partial, when the stroke is shorter than 100% of the total length of the rail in its closed position and the rail is made up of 2 elements
- Full, when the stroke is between 100% and 150% of the length of the rail in its closed position and the rail is made up of 3 elements
- Overextended, when the stroke is over 150% of the length of the rail in its closed position and the rail is made up of 4 or more elements.
In most cases, telescopic rails use caged steel balls as rolling elements, but that is not always true.
Indeed, there are also telescopic rails with roller bearings, which have characteristics which make them the ideal solution for a variety of applications.
With this in mind, we can identify a selection of different use cases in which the first question that the designer might want to ask themselves is:
“What type of rolling element do I want in the telescopic rail I’m looking for?”
Let’s take a look at them in detail:
Telescopic rails with roller bearings are particular well-suited to use in industrial automation settings, both due to their ability to work in a continuous cycle, with high dynamics and variable strokes, and due to their high load capacity.
One example of a specific use of these rails is in bottling and labelling machines, where the rail allows them to move the coil on which the roll of labels is applied quickly and with frequent variations of extension, thus allowing them to be applied directly onto the bottle.
If the designer finds themselves tackling an application that involves vertical movements, telescopic rails with roller bearings are the perfect solution thanks to their large rolling elements and lack of cage.
There is an incredibly wide range of use cases, from industrial production to operating rooms: any situation in which vertical telescopic movement is required.
Unaligned mounting surfaces
The rigidity of a pair of rails can become a limitation in many applications which do not require a particular degree of precision, but where the surfaces the rails are mounted on are significantly misaligned.
Telescopic rails with roller bearings, however, make it easy to manage significant misalignments between mounting surfaces thanks to the fact that the roller can rotate by up to 2°, thus allowing it to compensate for differences in size between the fixed and moving parts of the structures they are mounted to, as well as parallelism defects of up to 3mm.
To choose the telescopic rail best suited to industrial automation applications, read our in-depth report: