US Patent 8091294 Folding pet staircase

A method and apparatus are provided, for allowing pets to ascend and descend on a foldable staircase having a plurality of stair treads operatively connected by articulating links in such a manner that the treads can be pivoted in unison from a stowed position of the staircase, in which the treads are substantially stacked upon one another, to a plurality of extended positions, in which the links position the treads in a spaced and parallel relationship to one another. A latch selectively secures the staircase in a selected one of the extended positions. The latch is configured for preventing further pivoting of the treads in either direction between the stowed and extended positions of the staircase, when the latch is engaged.