Patent ID: 6256946
Filing Date: 2001-07-10
Classification: E04F,E21F

Abstract:
A stairway for a mine air crossing installed in a mine passageway, comprising:a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower parallel stringers disposed one above the other at a respective side of the stairway;a plurality of generally horizontal steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway whereby said steps remain generally horizontal regardless of the angle of inclination of the stairway and regardless of a mine convergence or divergence causing a longitudinal shift of an upper stringer relative to a lower stringer; andhandrails mounted on the steps at opposite sides of the stairway;each handrail comprising a plurality of generally vertical posts each having a lower end attached to a respective step and an upper end, and a hand bar having generally horizontal pivot connections with the vertical posts adjacent their upper ends, said hand bars being removable from respective posts so that when the stairway is moved to a position in which said supports are vertical, said vertical posts of the handrails are positioned to be grasped by a person climbing the stairway.