This invention relates to devices for building shelters to span between walls or to rest directly on the ground, and for bridging obstacles to enable pedestrians and vehicles to traverse the obstacles. More particularly, this invention relates to a portable structure, or bridge, comprising a plurality of elements connected to one another by a tension device.
This invention was intended to fulfill the need for easily transportable structures, simple in design, and able to be quickly erected as a bridge and/or shelter. Such shelter or bridge would satisfy the demand for emergency and rescue operations where instant bridges or shelters are necessary. The army requires light mobile bridges that can be speedily erected and light structures to facilitate storage and shelter for soldiers and equipment.
Existing military mobile bridge solutions are bulky, costly and heavy to transport. For example, the Armored Vehicle Launcher (AVLB), the XM104 Wolverine and the Leguan Bridge are not lightweight structures that are simple to construct and transport. Previously available lightweight mobile bridge structures are not designed or capable of carrying heavy loads like cars, tanks and trailers.
Consequently, a need exists for an improved mobile bridge or shelter structure which is simple to construct, mobile, lightweight and inexpensive to manufacture.
The present invention is directed to a lightweight shelter, roof or bridge structure which is mobile and easily erected. The structure is made of a plurality of elements which could be poles or tubes having a cross-sectional shape of a square, U-shaped, triangle, rectangle, trapezoids, circle, I-beam or any combination thereof. The elements are produced from plastic, polymers, wood or metal. The elements are laid together and the lower surfaces of the elements are connected by a tension device which could be cables, mesh or straps. The entire structure can be folded or rolled into a cylindrical shape for mobility.
The structure of the present invention is a low cost, self-contained unit which may be carried on a truck bed, trailer, tractor, tank or ship and transported very easily to any desired location. The device is designed in such a way that the bridge elements can move relative to one another, and, for example, could be rolled upon itself or around a reel for transport. Accordingly, the device does not occupy a large space. The bridge structure or shelter can be designed for use by pedestrians, civilian or military vehicles, including tractors and tanks. An advantage of the present invention is that it can be erected in a very short time as once the structure is unrolled and supported at both of its ends, it is ready for service. Another advantage of the present invention is that the device is a self-contained unit, and once it is erected it can be operated without an outside power source, and requires little or no maintenance. The bridge structure can be extended to any desired length in proportion to the size of its individual elements and tension device. The device does not require a large crew to transport or operate and can be used on land or span over water. The device is portable and has an excellent strength-to-weight ratio and can be quickly deployed without the use of any additional supports.
The invention is described in more detail herein with reference to the accompanying drawings, wherein like reference characters refer to the same parts throughout the several views and in which:
Referring to
As shown in
As seen best in
The mobile compression and tension bridge 10 of the present invention provides its own rigidity and stability for an extended bridge structure as weight is placed upon the bridge. As the bridge is loaded, the top part of the bridge elements will absorb compression forces and the tension members at the bottom of the bridge elements will absorb the tension forces. As the bridge carries a heavier load, the arch shape will become flatter and the tension members will bear more and more of the load. As the arch becomes more flat, the supporting ends of the bridge will move outward. When the load is removed from the bridge, the bridge may resume its original arch form and the supporting end components will move inward. Optionally, beams can be placed on the top surface of the bridge compressed from one end to another when the bridge is fully loaded to maintain the structure permanently in a compressed position. Further optional components can be used with the bridge structure such as railing, which could be an L-shaped post positioned in the opening at the end of the bridge element, securing it with bolts and connecting the tops of these posts by a rope or a cable to create a railing. These railings could be connected to each other with diagonal cables and create another method to sustain the bridge permanently in one position.
In order for the bridge elements to form an arcuate contour in an extended position, the bottom of each individual bridge element could have a width shorter than the top portion of each element, i.e. trapezoidal, or narrow inserts 26 as shown in
Because of the ability to be flexible, the bridge structure can be rolled onto a reel 28 as shown if
The transport reel 28 is preferably circular and constructed of metal, plastic or composite fiber. The reel may be driven by a motor or include a crank to be manually actuated. The entire device may be mounted on a trailer to be towed or positioned on a truck bed 30 as shown in
As shown if
While the present invention has been shown and described in terms of multiple embodiments thereof, it will be understood that this invention is not to be limited and that changes and modifications can be made without departing from the scope of the invention as hereinafter claimed.
This application claims the benefit of U.S. Provisional Patent Application No. 60/785,659, filed Mar. 23, 2006, the disclosure of which is hereby incorporated by reference herein.
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Number | Date | Country | |
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20070234490 A1 | Oct 2007 | US |
Number | Date | Country | |
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60785659 | Mar 2006 | US |