They allow the load / unload of the material from the machine, or they are used to move it along the establishment.
They are composed of basic elements, whose union forms a roller way. These elements can be motorized or not. There are various types of roller ways to adapt to the technical specifications expected for each machine or installation, differentiating in width, pitch between the rollers and capacity.
It's possible to move the material also by connecting two roller ways at 90°, thanks to special executions of rotating systems.