Fire escape – ladder – or scaffold – Wall- or floor-attached – Wall-mounted platform – with ladder
Reexamination Certificate
2000-07-06
2002-06-11
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Wall- or floor-attached
Wall-mounted platform, with ladder
C182S086000, C182S206000
Reexamination Certificate
active
06401861
ABSTRACT:
TECHNICAL FIELD
This invention relates to ladders which are adjustable to accommodate dumpsters having side walls of different heights or shapes.
BACKGROUND ART
There is a great need for dumpster loading apparatus that will facilitate the safe and efficient loading of debris into conventional construction site dumpsters. Customary methods of filling dumpsters have been found to be time inefficient and unsafe.
Currently, dumpsters are loaded by two conventional methods. The first one of these methods is the carrying of the debris through the dumpster door. This process entails that a worker walk an additional distance to the entrance of the dumpster, walk to the accumulation of trash inside the dumpster, and finally unload the debris onto the pile. The problem with this method is that it is time consuming. The second method is the removal of waste or debris by throwing it over the side wall of the dumpster. This process is also inefficient in that it does not allow for the effective piling of debris in the dumpster because the thrower cannot see where the refuse will land.
Prior art designs disclose step ladder systems that attach to the rear of trucks or campers. Such systems are deficient in transportability, foldability, attachability and size.
More particularly, U.S. Pat. No. 4,482,029, issued Nov. 13, 1984, to Prochaska, discloses a ladder assembly for a truck box. The ladder remains vertical regardless of the inclination of the truck box. An outer frame of the ladder is pivotally connected to an inner frame with steps in between.
U.S. Pat. No. 381,429, issued Apr. 17, 1888, to Scott, discloses wagon steps which hang from the wagon box. The steps are pivotable on side supports which are foldable.
U.S. Pat. No. 599,666, issued Feb. 22, 1898, to Thornton & Moody, discloses portable wagon steps which hang on a wagon bed and are foldable compactly when not in use.
Other foldable ladders have been disclosed for boarding boats and planes, such as U.S. Pat. No. 2,551,345, issued May 1, 1951, to Scott, and U.S. Pat. No. 3,892,290, issued Jul. 1, 1975, to Lang.
Such prior art fails to solve the problems faced in efficiently loading a trash dumpster which may be resting on a shifting or unstable ground support.
By creating a portable ladder that allows the worker to see over the top of the dumpster, the problem of inefficient packing will be alleviated. The time factor will also be greatly improved through the strategic placing of the ladder, which will eliminate the need to walk the extra distance to the dumpster door. By preventing the workers from throwing the waste or debris over the side wall, and by removing the threat of navigating through the dumpster's door to pile debris, a more convenient way of disposing debris at construction sites has been invented.
DISCLOSURE OF INVENTION
The dumpster loader of this invention is an attached, free-floating step ladder system with raised platform that has foldable and telescoping characteristics.
Accordingly, it is an object of this invention to provide an improved ladder which allows workers to load dumpsters more quickly and efficiently.
It is another object that the improved ladder of this invention be sufficiently compactable and lightweight to be portable, both between construction sites and around the dumpster.
Another object of the invention is an improved portable ladder which is adjustable to accommodate all dumpsters and landscapes and easily assembled and set up on the dumpster.
Another object of the invention is a free-floating step ladder which has a hanger adapted for hanging on an upper rim of a dumpster possibly supported on unstable sand or ground. The ladder has a platform affixable to the hanger and a stairway extending from the platform and supported from the hanger by a flexible or adjustable means extending restrictively toward the ground so that the stairway is prevented from touching the ground sufficiently that the ladder will not sink into the unstable ground which supports the dumpster.
A more specific object of the invention is a portable ladder to aid a worker in loading dumpsters of different heights which are on a dumpster support which may be unstable. The ladder has a stepless hook portion adapted for connecting the ladder to a dumpster of predetermined height and shape. It also has a platform portion for the worker to stand on which is adjustably positionable with respect to the hook portion and affixable to the hook portion at a desired position alongside the dumpster sufficient to enable the worker when on the platform portion to see how to load the dumpster. The ladder has a stairway portion depending from the platform portion, and a flexible support for the ladder portion suspended from the hook portion and positionable at an angle sufficient with respect to the dumpster support for spacing the ladder portion above the dumpster support.
The ladder may also have a fixed section of the stairway portion positionable with respect to the platform portion by the flexible support and one or more foldable sections pivotable with respect to the fixed section so that the fixed section and foldable sections can lay side by side when the dumpster has a short side wall so as to clear the ground when in use or to make the ladder compact and portable.
The ladder may also have a foldable portion which is extendable toward the dumpster supporting site when the hook portion is connected to a dumpster having a taller side wall or a different rim shape so that the hook portion can be adjusted or reshaped to fit the top rim of the dumpster and the bottom of the ladder can remain spaced from the ground on which the dumpster is placed.
In general, the dumpster ladder of this invention is a small set of stairs that can be placed in front of the dumpster and locked onto the dumpster rim for stability. The hook that locks the stairs in place is adjustable for dumpsters of different height and rim shape. The ladder of this invention is very easy to move from site to site or to different positions on the dumpster because it is relatively small and lightweight. It is also easily slid along the side of the dumpster to ensure even distribution of debris; and if workers can see where they are placing the debris, they can pack the dumpster more efficiently. The ladder is also extremely time efficient since the workers just walk up the stairs, throw away the debris, and walk down. It is not unrealistic to ask workers to climb a short flight of stairs because generally they will already have walked a reasonable distance through the work site to the dumpster. Lastly, the ladder is very durable, requires next to no maintenance, and is inexpensive to build when considering the features offered.
There may be a problem when the ladder rests on the ground of the construction site. The ground conditions may be unstable, such as sand or mud, or uneven such as where only one point of the stair feet rests on the ground to support all of the weight. Thus, the ladder design of this invention is adaptable to different dumpster applications. And for these reasons, the ladder of this invention has a floating stair design that depends entirely on the dumpster for support by being spaced from the ground on which the dumpster sets.
The floating ladder design of this invention has two foldable stairs on the bottom, two top hooks for attaching it to the dumpster, pins in the hooks to adjust the height of a standing platform and a system of metal tubes to stabilize and orient the ladder against the dumpster. This insures a level platform and treads at all times. These tubes are also adjustable to accommodate dumpsters of different height and rim shape. This floating design works well. The metal tubing is strong enough to withstand the loads on the stairs and platform. Also, the structure is light enough to be portable. Because aluminum is much lighter than steel and has a higher strength-to-weight ratio, the tubing is aluminum to reduce weight. The resultant structure is not significantly heavier at about 70 lbs. than the initial target weight of 4
Brooks & Kushman P.C.
Chin-Shue Alvin
Great Lakes Construction Services
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