described belt cleaning structure is preferred certainly variations are conceived which may differ for example with regard to specific sizes materials and arrangement of various parts but which are still within the scope of the invention in which the belt cleaning brush is automatically driven by the belt roller head or pulley shaft and is adjustably mounted for optimal automatic belt cleaning operation without the need for a separate motor additional to that which operates the conveyor as will be described fig7 schematically illustrates one of a series of sets of three rollers referred to as 34 tri rollers 34 78 which are provided at spaced intervals approximately every four and one half to five feet along the length of main body 12 internally thereof tri rollers 78 are rotatably supported by upstanding l brackets 80 fixed on the upper side of at least some of transverse braces 34 previously discussed in such manner that in each set of tri rollers one of the three rollers is disposed approximately centrally horizontally and transversely within main body 12 and the remaining two rollers extend from their respective positions one adjacent each end of the centermost roller at a slight angle upwardly and outwardly therefrom so positioned tri rollers 78 function as rolling support or 34 idlers 34 for upper reach 40a of endless belt 40 as it travels with its load of.