They allow the load / unload of the material from the roller ways, moving the material in a direction perpendicular to the motion of the rollers' ways. The material is moved in a perpendicular direction respect the movement of the roller ways.
For each roller way there is a cross field, formed by a certain number of single modules, called conveyors. The quantity of conveyors per field depends on the length of the material to be moved. These machinery also have the task of acting as buffer for the system; in fact it is possible to store more semi-finished products which will be loaded one at a time on the roller way. This type of conveyors, works by push-sliding, thanks to a catcher that hooks the material and moves it towards the roller way or outside it.