Disclosed herein is a street sweeper having a vertical chain driven conveyor apparatus. The vertical chain driven conveyor apparatus is provided with a jointed shaft to compensate for chain wear over the life of the chains. The vertical chain driven conveyor apparatus is provided with an automatically adjusting chain tension adjustment system. The vertical chain driven conveyor apparatus is provided with locking adjustment mechanism to prevent the chains from losing tension when the sweeper is turned off. An initialization program is operable to restore chain tension when the street sweeper is started and prevent sweeping operations until a desired chain tension has been indicated.