Belt conveyor apparatus

Claim 1

A belt conveyor apparatus comprising: an endless major belt having at each opposite lateral edge portion thereof, on the underside of the upper run thereof, a single substantially flat contact surface, said lateral edge portions being thicker than the middle portion between said lateral edge portions; non-driven guide rollers mounted for supporting said endless major belt; a plurality of sub-belt means mounted for contacting said major belt at said opposite lateral edge portion contact surfaces only thereof for imparting rotation to said major belt, each of said sub-belt means comprising, adjacent each of said lateral edge portions of said major belt: a driving pulley a following pulley; a sub-belt having a single outer substantially flat contact surface and mounted over said driving and following pulleys to be driven by said driving pulley, said sub-belt being substantially narrower than said major belt and being mounted to be in strong frictional contact at said flat contact surface thereof with the respective one of said lateral edge portion contact surfaces only of said major belt; and at least one snap roller means mounted to contact the upper side of said upper run of said major belt at said respective lateral edge portion only thereof, said snap roller means comprising a freely rotatably mounted snap roller for pinching said major belt and said sub-belt together; the lateral edge surfaces of said major belt being free from contact with said sub-belt means; and said sub-belt means being spaced from and not in contact with the lower run of said major belt.