Silo door construction

Claim 1

In a silo including a peripheral wall having inner and outer wall surfaces and defining an opening therethrough extending for the greater part of the height of said peripheral wall: a. a vertical door frame in said opening and including a pair of elongated vertical side frame members extending substantially the length of said opening and secured to said peripheral wall at opposite sides of said opening, said side frame members defining opposed guide channels; b. an elongated flexible metal door having a length at least equal to that of said opening and having opposite longitudinal side edges each longitudinally slidably received in a different one of said guide channels; c. a rotary drum journaled adjacent the lower end of said door frame, the flexible door having a lower end secured to said rotary drum and adapted to be wound thereon to move the door in a downward door opening direction; d. an elongated flexible member connected to the upper end of said flexible door and extending upwardly therefrom to a level adjacent the upper end of said opening; e. a second drum, said flexible member being secured to said second drum for winding thereon to move said door in an upward door closing direction; f. and means for imparting rotation to said drums selectively in opposite directions.