Raised elements are sometimes used on a belt surface to assist in the carrying of material. These cleats, ribs, chevrons, and lugs are generally used to allow a conveyor to carry material at a higher angle of incline than would generally be possible with a flat belt. This is particularly useful with lumps or stones that could easily roll down an unobstructed incline.
Cleats, or ribs, can be seen as walls or shelves installed perpendicular to the lines formed by the belt edges. Chevrons are in a V-shaped arrangement. Lugs are individual "islands" or pillars in the belt’s surface. All are available in a variety of patterns and styles, with heights determined by the application. They can be molded integrally into the surface during the belt’s original manufacture, or they can be bolted or vulcanized to the surface of the belting.
Bear in mind that the taller the cleats, ribs, chevrons, or lugs are, the more vulnerable they are to damage and the harder the belt is to clean and seal.
One way to increase traction between the belt and the conveyed material is to use a top cover that features inverted chevrons. Instead of extending above the belt cover, inverted chevrons are recessed into the top cover, like the tread on a tire. The grooves are cut into the belt cover with a router; the grooves can be at a chevron angle or straight across the belt 90 degrees to the edge. This design allows greater success in cleaning and sealing the belt with traditional systems, although it is possible to fill the recessed cleats with material.
Details about cleats, ribs, chevrons and lugs can be found in Chapter 4 of Foundations™ Fourth Edition by Martin Engineering.