Patent ID: 8607930

Claim:
A ladder for mounting to a trailer to allow access to the trailer, the ladder comprising: a pair of side rails, the side rails having a length defined between an upper, first end and a lower, second end, an inner channel passing between the first end and the second end and defined by at least four sides having inner and outer surfaces, and an upper, first slot in one of the sides passing from the inner surface to the outer surface and extending from the first end to a middle portion of the side and a lower, second slot in one of the side passing from the inner surface to the outer surface and extending from the second end to the middle portion of the side, wherein the upper, first slot does not extend to the lower, second slot; one or more ladder rungs extending between the side rails; each side rail further including a respective first pin or bolt extending from at least one side of the channel, the side being perpendicular to the side through which the first, upper slot is formed; a pair of bars, each bar having a length and a lengthwise slot at one end of the bar along a portion of the length of the bar, each respective first pin passing through the lengthwise slot in the respective bar whereby the respective bar can pivot about the respective first pin when one end of the lengthwise slot is positioned against the pin but the bar cannot pivot about the respective first pin when the opposite end of the lengthwise slot is positioned against the pin, and each respective bar has a length that is longer than the length of the lower, second slot whereby when the bar is positioned within the inner channel a portion of the length of the bar is surrounded by the four side walls of the side rail such that the side walls limit the ability of the bar to pivot about the first pin; and a bearing or wheel positioned within the upper, first slot and mounted to a second pin or bolt, the bearing movable along a surface of the inner channel, whereby the bars are configured to be pivotally mounted to first mounting plates and extend through the lower, second slots and the second pins are configured to be mounted to second mounting plates such that when the ladder is moved to a vertical, retracted orientation the bearing is movable against an inside surface of the inner channel along the length of the upper, first slot to a position at a first end of the upper, first slot and the bar pivots at one end with respect to the first pins and at a second end with respect to third pins extending from the first mounting plates, and when the ladder is moved to an extended orientation the bearing is movable against the inside surface of the inner channel along the length of the upper, first slot to a position at a second end of the upper, first slot and the bar pivots at one end with respect to the first pins and at a second end with respect to the third pins extending from the first mounting plates.