Patent ID: 9027711
Filing Date: 2015-05-12
Classification: E06C

Abstract:
1. A self-locking, bi-folding load bearing segment, the load bearing segment comprising: a first section comprising a first rail, a second rail, and a first plurality of hollow tubular rungs pivotally attached to and extending between the first and second rails in a parallelogram linkage, such that a separation between the first and second rails is adjustable between an un-collapsed configuration with the rungs generally perpendicular to the first and second rails and a collapsed configuration with the rungs at an angle of less than 30 degrees relative to the first and second rails, the first and second rails restricting rotation of the first plurality of rungs from the un-collapsed to the collapsed configuration to a first direction relative to a front face of the load bearing segment; a second section comprising a third rail, a fourth rail, and a second plurality of rungs pivotally attached to and extending between the third and fourth rails in a parallelogram linkage, such that a separation between the third and fourth rails is adjustable between the un-collapsed configuration with the rungs generally perpendicular to the third and fourth rails and the un-collapsed configuration with the rungs at an angle of less than 30 degrees relative to the third and fourth rails, the third and fourth rails restricting rotation of the second plurality of rungs from the un-collapsed to the collapsed configuration to a second direction opposite the first direction relative to the front face of the load bearing segment; a first hinge pivotally attaching the first ladder rail to the third ladder rail; and a second hinge pivotally attaching the second ladder rail to the fourth ladder rail, wherein the first and second hinges allow the first and second sections to be rotated between an open configuration to the folded configuration, wherein the first and second plurality of rungs on the first and second segments rotate in the same direction relative to the rails when in the folded configuration to permit the rails to be moved between the un-collapsed configuration to the collapsed configuration, and wherein the first and second plurality of rungs on the first and second segments rotate in opposite directions when in the open configuration to automatically lock the first and second segments in the un-collapsed configuration, wherein no separate locking mechanism is required to lock the first and second plurality of rungs in the un-collapsed configuration when the load bearing segment is in the open configuration.