Abstract: Apparatus for unloading material from a silo comprises a chain drive wheel located near a discharge opening on one side of the silo, a chain idler wheel, a pair of angularly spaced apart rotatable chain guide wheels mounted on a ring which is drivable in a circular path around the silo floor, and an endless flexible cutting chain reeved around the aforesaid wheels. A drive mechanism is provided to drive the ring in the circular path and to rotate the chain drive wheel to drive the chain as the chain guide wheels move, whereby reaches of the chain sweep across the silo floor to unload the material through the discharge opening. The chain drive wheel and drive mechanism therefor are located outside the opening in the silo. The chain idler wheel is located inside the silo and within the ring. Protective devices are provided on the silo floor to prevent that reach of chain extending between the chain drive wheel and the chain idler wheel from being subjected to pressure from material thereabove in the silo.