Abstract: An undercarriage for a mobile ladder stand or other similar warehouse apparatus includes a pair of retractable wheels located at the rear of the undercarriage frame and a pair of retractable wheels located at the middle of the undercarriage frame. When the wheels are retracted, the structure is supported by a pair of legs and foot pads located at the front of the undercarriage frame and another pair of legs and foot pads located at the rear of the undercarriage frame. When the wheels are extended, the structure is supported on the ground surface for rolling by the middle and rear wheels. The rear wheels are preferably mounted on swivel casters and the diameter of the middle pair of wheels is preferably greater than the diameter of the rear pair of wheels.

Abstract: A combined stepped structure and lifting mechanism includes a base and a framework secured to the base, the framework having a pair of spaced apart vertical tubes rising upwardly from the base. A ladder is incorporated in the framework and a vertical track assembly is disposed between the vertical tubes and includes a pair of tubular members connected together. A trolley is rollably mounted for movement along one of the tubular members. A lifting tray assembly is connected for movement with the trolley. A drive system is operably connected to the trolley and driven by a DC motor and gearbox unit mounted to a bottom end of the vertical track assembly to selectively move the lifting tray assembly upwardly and downwardly along the vertical track assembly.