Abstract: A bottom silo unloader is disclosed in which a tapered sweep auger has its inner end of largest diameter supported for rotation about a transverse vertical axis at the center of a silo so that it sweeps over the silo floor as it is also rotated on its longitudinal axis to feed material to a center-located hopper therebelow with which a discharge auger communicates. The outer smaller end of the sweep auger is spaced off the silo floor and unsupported other than through the driven inner end. In its specifically disclosed form the tapered shaft of the sweeper auger is composed of three equal length sections of constant diameter, the diameters of which are progressively increased from shaft section to shaft section in the direction of the supported inner end of the sweep auger.

Abstract: A bottom silo unloader for use in discharging moist grain from a sealed silo has a discharge tube set in the silo floor that leads from a casing in the center of the silo below floor level to the outside, and a discharge auger in the casing is driven by drive means adjacent the outer end of the tube. A pair of vertically aligned, right angle gear boxes are driven by the discharge auger and drive a sweep auger. A ring gear on which the upper gear box is mounted is rotated from the drive means to cause the sweep auger to rotate about the vertical axis of the silo and the gear boxes. A torsion arrangement suspends rotation of the ring gear when the sweep auger encounters heavy resistance to its movement around the silo.