US Patent 7607724 Collapsible support structure

An apparatus including a support structure movable between an erected position and a collapsed position and including a threaded shaft, a first collapsible assembly having a first portion pivotally mounted on the threaded shaft, a second collapsible assembly having a second portion pivotally mounted on the threaded shaft, where at least one of the first and second portions is threadably engaged to the threaded shaft such that the first and second portions are relatively movable toward and away from each other through a rotation of the threaded shaft to move the support structure between the erected and collapsed positions.