Foldable ladder

A ladder comprising a pair of side rails and a plurality of rungs, a hinge positioned between each rung and each of the side rails such that the side rails are free to rotate from positions substantially coplanar with the rungs to positions defining a plane substantially normal to the rungs to support the rungs, the hinges between the rungs and the side rails being disposed to permit relative rotation of the side rails not more than 90.degree. from the position substantially coplanar to the rungs and each hinge including a plurality of ribs formed integral with the side rail and extending outwardly from a side thereof and a plurality of ribs formed integral with the rung at an end thereof, the ribs each having an aperture therethrough aligned with the apertures of adjacent ribs, the ribs of the rung being meshed with the ribs of the side rail with their apertures in alignment and a hinge pin extending through the aligned apertures, and the side rails being formed in segments attached at their ends by segment hinges such that the side rails can be folded into an accordion arrangement, the segment hinges each including a plurality of end ribs formed integral with the segments and extending outwardly from an end thereof each end rib having an aperture therethrough aligned with the apertures of adjacent end ribs, the end ribs of the segments being meshed with their apertures in alignment and a hinge pin extending through the aligned apertures, wherein an elastic cord is connected between at least one rung and each side rail adjacent the rung, the elastic cord being under tension and positioned to drive the side rails from the position substantially coplanar with the rung to the position wherein each side rail defines a plane substantially normal to the rung.