| 摘要 |
The present invention is directed to an access door assembly (10) comprised of a frame assembly (12) held in place by a plurality of hoop-shaped rods (14). A door (16) is hinged to frame assembly (12) using a pair of first hinge brackets (18) secured to frame assembly (12), a pair of second hinge brackets (20) secured to door (16) near its vertical centerline, and a connecting rod (22) acting as the hinge pin between the first and second hinge brackets (18, 20). A latch mechanism (24) engages a mid-step member (26) to secure door (16) tightly against a door frame structure (28). In doing so, flexible door (16) bends to conform generally to the curvature of cylindrical silo wall (30). Upper and lower step members (56, 58) are a part of frame assembly (12) and mid-step member (26) is supported by frame assembly (12). Hence the step members acting as ladder rungs are not supported by door (16), but rather by its frame.
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