Land vehicles – Wheeled – Extensible
Reexamination Certificate
2000-05-02
2001-12-11
DePumpo, Daniel G. (Department: 3611)
Land vehicles
Wheeled
Extensible
C280S030000, C280S047290, C280S643000, C182S021000
Reexamination Certificate
active
06328330
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to devices for attaching to a ladder, and to ladders in combination with such devices. More specifically, the present invention relates to a wheeled attachment for a ladder, to allow the ladder to function as a hand truck.
2. Description of the Relevant Art
Service persons, such as electricians, plumbers, and heating and air conditioning mechanics, often work at sites remote from their shops or offices. Typically, tools and materials are transported to the work site using a service truck. Also, it is common that many jobs require the use of a stepladder.
Once the service truck is driven and parked close to the work site, the stepladder, tools and materials for the specific job must be carried from the service truck to the work site. When working in a location remote from the parking area, significant time is consumed carrying the stepladder, tools and materials to the work site. For example, one trip between an upper floor of a high rise building and a remote parking location can take more than half an hour. If several trips are required to bring the step ladder and all the necessary tools and materials to the work site, the total cost of the work is greatly increased. Therefore, the fewer trips required between the service truck and the work site, the more cost effectively the work can be performed.
One solution to carrying a stepladder, tools and materials between the service truck and the work site would be to use a hand truck. A hand truck offers a great conveyance, and eases the burden of the service person. However, if a service person were to use a hand truck, this would require that a hand truck be carried in the service truck. It is well known that space inside a service truck is limited, and often completely accounted for in accommodating the necessary stepladder, tools and materials.
To this end, a piece of equipment consolidating a stepladder and a hand truck has been proposed in the background art. U.S. Pat. No. 5,382,032, issued on Jan. 17, 1995 to James R. Wilson, and U.S. Pat. No. 3,954,155, issued on May 4, 1976 to Orlando Guidara, both illustrate a stepladder with wheels, which can function as a hand truck. Unfortunately, the devices of the background art suffer drawbacks.
Both references disclose fixed wheels, which protrude away from a top portion of the ladder. When a person uses the stepladder, the placement of the wheels encroaches on the user's upward movement. The encroachment forces the user to lean away from, rather than into the stepladder, especially as the user ascends higher on the ladder. Good safety practices recommend that a user should lean into, rather than away from, the ladder.
Another drawback is that the protruding, fixed wheels can be an obstacle to the user, and push against a user's body, when standing on the ladder and trying to reach to the sides of the ladder. If the wheels protrude above the top of the ladder, the wheels will interfere with placing and balancing a flat object, such as a board or a saw, on the flat top surface platform of the ladder.
Yet, another drawback is that the wheels are exposed in a prominent location at the top of the ladder, when the ladder is in use. If a user lost their balance, the user might grasp for the wheels to regain their balance. Since the wheels are rotatable, they would not lend themselves well for grasping in an emergency.
Another significant drawback is the positioning of the fixed wheels outside the limits of the side rails. In other words, the outer profile, or footprint, of the ladder is altered by the wheels when the ladder is folded up for storage. This arrangement requires additional space for storing the background art's device in a service truck. Further, the background art's device may not fit into a standard ladder rail, often provided on the top or side of a service truck.
SUMMARY OF THE INVENTION
The present invention has as a primary object to solve one or more of the drawbacks associated with the background art.
It is an object of the present invention to provide a device for attachment to a ladder, which allows the ladder to function as a hand truck, wherein a wheel assembly is located so as to be remote from a person on the ladder in order to not interfere with the person's use of the ladder.
It is a further object of the present invention to provide a device for attachment to a ladder, which allows the ladder to function as a hand truck, wherein a wheel assembly is located so to be remote from a top of the ladder in order to not interfere with the use of the top of the ladder.
It is an even further object of the present invention to provide a device for attachment to a ladder, which allows the ladder to function as a hand truck, wherein the device does not significantly change an outer profile of the ladder when the ladder is in a storage condition.
Moreover, it is an object of the present invention to provide a device for attachment to a ladder, which allows the ladder to function as a hand truck, wherein the device attaches to the ladder without structurally altering the ladder.
These and other objects are accomplished by a combination comprising: a ladder including a plurality of steps; and an assembly attached proximate an end of said ladder, said assembly including: a pivotable linkage, said pivotable linkage being pivotable between a first position and a second position relative to said ladder; and at least one wheel mounted to said pivotable linkage.
Further, these and other objects are accomplished by an assembly for attachment to a ladder, said assembly comprising: a base for fixing proximate an end of the ladder; a pivotable linkage attached to said base, said pivotable linkage being pivotable between a first position and a second position relative to said base; and at least one wheel mounted to said pivotable linkage.
Moreover, these and other objects are accomplished by an assembly for attachment to a ladder, said assembly comprising: a base for fixing proximate an end of the ladder, said base including a first bracket and a second bracket, said first bracket for abutting one side of a first rail of the ladder, said second bracket for abutting another side of the first rail of the ladder, and at least one first fastener for connecting said first bracket to said second bracket in order to frictionally fix said first bracket and said second bracket to the first rail of the ladder; a linkage attached to said first bracket; and at least one wheel mounted to said linkage.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
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Birch & Stewart Kolasch & Birch, LLP
DePumpo Daniel G.
Shriver J. Allen
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