Arrangements in silos for storing vault-forming materials

Claim 1

In a silo for storing vault-forming materials, having hollow bearing means at the upper part of the silo, motor means on said bearing means, and unloading means comprising a common horizontal conveyor means in continuous contact with the material stored in said silo, and a central vertical screw conveyor means extending from said hollow bearing means into a bottom opening of the silo, said horizontal conveyor means being suspending from and supported by said hollow bearing means for upward and downward movement of said horizontal conveyor means; the improvement wherein said vertical screw conveyor means comprises a rotatable tubular vertical shaft and a screw thread on the outer side of said shaft and being driven at one end thereof for conveying the stored material out of said silo, an elongated member axially disposed within said tubular shaft and having a lower portion fixed to said tubular shaft for rotation therewith and having an upper portion mounted for rotation relative to said tubular shaft to permit, upon rupture of the tubular shaft, lifting and withdrawing the screw conveyor from the stored material.