Bottom silo unloader

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.

We claim: 
     
       1. In a bottom silo unloader for use in the discharge of moist grain from a sealed cylindrical silo that has a floor with a center discharge hole, in combination: a casing in said discharge hole that has an upper edge substantially flush with the floor;   a discharge tube communicating with said casing beneath the floor, said discharge tube having a discharge opening outside the line of the silo wall and an airtight closure for said opening;   a discharge auger in said discharge tube;   drive means mounted outside the silo and drivingly connected to said discharge auger;   a lower right angle gear box in the casing which has a horizontal input shaft coupled to the discharge auger;   means at the bottom of the casing restricting movement of said lower gear box;   an upper right angle gear box having a horizontal output shaft;   a vertical shaft drivingly connecting said gear boxes;   a sweep auger above the silo floor and rigidly drivingly connected to the output shaft of the upper gear box for revolving the sweep auger on its axis to feed grain into the casing;   a ring gear supported in the upper part of the casing for rotation about the axis of the vertical shaft;   means mounting said upper gear box on said ring gear;   and means for driving the ring gear from the drive means to rotate the sweep auger about the center of the silo.   
     
     
       2. The combination of claim 1 in which the means for driving the ring gear includes means responsive to high resistance to rotation of the sweep auger around the silo for suspending rotation of the ring gear until the high resistance is relieved by axial revolving of the sweep auger. 
     
     
       3. The combination of claim 2 in which the means for driving the ring gear includes a ratchet and eccentric pawl drive outside the silo, a ratchet shaft extending from the ratchet into the casing beneath the silo floor, and means on the ratchet shaft in driving engagement with the ring gear, torsional distortion of said ratchet shaft under heavy load causing the suspension of ring gear rotation by causing the ratchet to rotate reversely as the pawl withdraws from engagement with the ratchet. 
     
     
       4. The combination of claim 1 which includes generally radially extending means on the vertical shaft for moving grain into the discharge auger from the portion of the casing remote from said auger. 
     
     
       5. The combination of claim 1 in which the discharge opening is in the bottom of the discharge tube beneath the outer end portion of the discharge auger, and in which there is a generally radially extending feed pin on the discharge auger shaft above said discharge opening. 
     
     
       6. The combination of claim 1 in which the drive means includes a motor and reduction gear box which has an input shaft driven from the motor, said gear box having an output shaft directly coupled to the discharge auger. 
     
     
       7. The combination of claim 6 in which the means for driving the ring gear includes an output member on the gear box output shaft, and means including an intermittent motion device driven from said output member. 
     
     
       8. The combination of claim 7 in which the intermittent motion device includes a counter shaft driven by the output member, an eccentric on said counter shaft, a pawl reciprocated by said eccentric, a ratchet which has teeth engaged by the pawl, a ratchet shaft extending from the ratchet beneath the silo floor into the casing, and means on the ratchet shaft in driving engagement with the ring gear. 
     
     
       9. The combination of claim 8 in which the ratchet shaft can flex torsionally when the sweep auger encounters high resistance to rotation around the silo, said torsional flexing causing the ratchet to rotate reversely as the pawl withdraws from engagement with it, whereby rotation of the ring gear is suspended until said high resistance is relieved by axial revolving of the sweep auger. 
     
     
       10. The combination of claim 1 in which the casing has flange means near its upper edge on which the ring gear rests, a plurality of gear confining members surmounting said flange means substantially in contact with the ring gear, and a ring gear retaining plate supported on the flange means slightly above the ring gear. 
     
     
       11. The combination of claim 10 in which the casing is rectangular, the flange means comprises a flange member in each corner, there is a rotatable gear confining member on each flange member, and the ring gear retaining plate rests on spacers about which the gear confining members rotate. 
     
     
       12. The combination of claim 1 in which the ring gear has a circumferential array of equally spaced depending studs, and the means for driving the ring gear includes a horizontal driven shaft and a worm gear on said shaft which engages said studs to rotate the ring gear. .Iadd. 13. In a bottom silo unloader, the combination of a casing which sets in a discharge hole provided in the floor of a silo, a discharge tube which communicates with said casing adjacent the base thereof and has a discharge opening for location outside the line of the silo wall, a discharge auger in said discharge tube, drive means drivingly connected to said discharge auger; a lower gear box in the casing which has an input shaft coupled to the discharge auger; an upper gear box having an output shaft; a vertical shaft drivingly connecting said gear boxes such that the output shaft of the upper gear box turns on its axis with rotation of the input shaft of the lower gear box; a sweep auger to move over the silo floor which is drivingly connected to the output shaft of the upper gear box for revolving the sweep auger on its axis to feed material into the casing; a ring gear supported in the casing for rotation about the axis of the vertical shaft; the upper gear box being mounted on said ring gear to turn therewith; and means for driving the ring gear from the drive means to rotate the sweep auger over the floor of the silo about the axis of the vertical shaft. .Iaddend..Iadd. 14. The combination of claim 13 in which the means for driving the ring gear includes means responsive to high resistance to rotation of the sweep auger for suspending rotation of the ring gear until the high resistance is relieved by axial revolving of the sweep auger. .Iaddend.