To solve such a problem that cold in a storage tank leaks to the outside through rods even if it is a little, as the rods supporting rails are arranged to pierce the cold-reserving layer formed at the ceiling face and fixed to the steel plates constituting the external shell of the storage tank, in conventional ladders.
This ladder is provided with a body 10 rotatably supported at the ceiling face of a storage tank, a movable front end 20 transferably supported along the inside face of the tank in the state separated from the body 10, and a connecting structure 30 connecting the movable front end 20 to the body 10. The movable front end 20 which is guided by rails 5 suspended from the ceiling face 1 and supported therefrom and arranged in the circumferential direction of the storage tank and steel members arranged along the circumferential direction on the stage 6 provided along the inside face, can be transferred in the circumferential direction.
NAITO KIYOSHI
MIZOGUCHI YOSHIRO
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