Patent ID: 8057225

Claim:
A safety door for temporarily covering a manhole formed in a rotary kiln by removing a door which is secured to said rotary kiln during normal operation but is removed only during kiln maintenance operations said safety door being secured to said kiln only during said maintenance operations, said safety door comprising: (a) a hollow cylindrical rotary kiln having an interior and an exterior surface and a diameter large enough for an adult person to stand up inside the kiln; (b) a frame having first, second, third and fourth sides; (c) a plurality of openings defined by said frame sides; (d) a plurality of bolts secured to said kiln exterior surface adjacent said manhole, said bolts being received in said openings defined by said frame sides; (e) nuts secured to said bolts; (f) a hatch; (g) means for pivotally securing said hatch to said frame; and (h) means for continuously biasing said hatch toward said kiln exterior surface with a force sufficient to support approximately four hundred pounds placed on said hatch.