Mobile ladder with lifting tray
AssigneeEGA Products, Inc.
InventorsDavid T. Young, Scott E. Kaczor
Life of this patent
Estimating the term…
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.
Claims23
A combined stepped structure and lifting mechanism comprising:
- a base;
- a framework secured to the base, the framework having a pair of spaced apart vertical tubes rising upwardly from the base;
- a ladder incorporated in the framework;
- a vertical track assembly disposed between the vertical tubes and including a pair of tubular members connected together;
- a trolley rollably mounted for movement along one of the tubular members;
- a lifting tray assembly connected for movement with the trolley;
- and
- a drive system operably connected to the trolley and driven by a DC motor and gearbox unit mounted and juxtaposed to a bottom end of the vertical track assembly to selectively move the lifting tray assembly upwardly and downwardly along the vertical track assembly.
In a combined stepped structure and lifting mechanism having a movable base, a framework rising from the base, a ladder incorporated in the framework, a vertical track assembly secured to the framework, a lifting tray assembly mounted for movement along the vertical track assembly and a drive system mounted adjacent the base for selectively moving the lifting tray assembly along the vertical track assembly, the improvement wherein:
- the vertical track assembly is formed by a tubular structure extending between top and bottom portions of the framework;
- and
- the drive system is also mounted adjacent the bottom end of the vertical track assembly and includes a drive chain passing through the interior of the tubular structure which is entrained about an idler sprocket rotatably mounted at the top of the vertical track assembly and a drive sprocket which is driven by an electromagnetic DC motor and gearbox unit secured to a bottom end of the framework.
In a combined stepped structure and lifting mechanism having a movable base, a framework rising from the base, a ladder incorporated in the framework, a vertical track assembly secured to the framework, a lifting tray assembly mounted for movement along the vertical track assembly, and a drive system including a DC motor mounted adjacent the base for selectively moving the lifting tray assembly along the vertical track assembly, the improvement wherein:
- the drive system is also mounted adjacent the bottom end of the vertical track assembly;
- and
- a protective enclosure mounted on the base and having a battery connected to the DC motor for energization thereof, the enclosure having a lower structure and a top structure hingedly attached thereto, the lower structure carrying a battery recharger adapted to be connected to a source of AC power and the top structure being provided with a mercury switch on an inside surface thereof, whereby the battery recharger is operational only when the top structure is pivoted away from the lower structure to prevent the buildup of gases within the enclosure.
For use in retrofitting a mobile ladder having a movable base and a framework rising from the base with a ladder incorporated in the framework, a vertical track and lifting tray assembly comprising:
- a vertical track assembly having a pair of elongated tubular members connected together in side by side relationship, a trollery rollably mounted for movement along one of the tubular members, a generally planar lifting tray connected for movement on the trolley and a self contained direct drive system including a drive chain, which is connected to the trolley, passes through the interior of the tubular members and is entrained about an idler sprocket mounted for rotation at a top end of the vertical track assembly, and a drive sprocket rotatably mounted on a drive shaft;
- a DC motor and gearbox unit secured and juxtaposed to a bottom end of the vertical track assembly and providing mechanical power to drive the drive shaft;
- and
- a top horizontal cross tube mounted to a top of the vertical track assembly, said cross tube being adapted to connect to the ladder framework.
Dependencies are inferred from the claim text.