BRIEF DESCRIPTION OF THE DRAWINGS
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:
FIG. 1 is a perspective view of one embodiment of the present invention;
FIG. 2 is a schematic view of the geometry of individual bridge elements;
FIG. 3 is a bottom view of the bridge structure of the present invention illustrating a first tension device;
FIG. 4A is a bottom perspective view of a second embodiment of the present invention;
FIG. 4B is a cross-sectional side view of the embodiment of FIG. 4A with an alternative tension device;
FIG. 5 is a bottom view of a third embodiment of the present invention;
FIG. 6 is a side view of the embodiment of FIG. 1;
FIG. 7 is a side view illustrating one method of retracting the bridge device of the present invention and storing the bridge on a reel;
FIG. 8 is a schematic view of a first method of deploying the bridge device of the present invention;
FIG. 9 is a schematic view of a second method of deploying the bridge device of the present invention; and
FIG. 10 is a perspective view of the present invention as a shelter.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a mobile compression and tension bridge 10 of the present invention is illustrated. The bridge 10 comprises a plurality of bridge elements 12 which are connected to one another by a tension member, which is discussed in more detail subsequently herein. The bridge elements 12 are connected in a side-by-side fashion and they are adapted to form an arch when they are extended outwardly from base members 14. As can be seen in FIG. 1, the cross-sectional configuration of the individual bridge elements is square, however as can be shown in FIG. 2, the bridge elements 12 can have a variety of cross-sectional geometric configurations such as U-shaped 12a, square 12b, rectangular 12c, trapezoidal 12d, triangular 12e, circular 12f or I-beam 12g. It is to be understood that these geometrical configurations are by way of example and are not to be so limited since other geometric configurations may also be suitable for a particular application.
As shown in FIGS. 3 and 4, the individual bridge elements are attached to each other and held by a tension device 16 located on a bottom surface of the bridge elements. Preferably more than one tension device 16 are positioned along the lower surface of the bridge elements. FIG. 3 illustrates four metal strips spaced along the lower surface of the bridge elements and FIG. 4 illustrates two metal strips spaced apart along the lower surface the bridge elements. It is to be understood that any number of tension members can be located along the lower surface of the bridge element depending upon the width of the structure for the overall application.
As seen best in FIGS. 4A and 4B, the tension members are attached to each bridge element 12 by a fastener 18 which extends through the tension member and into the bridge element. By way of example, for bridge elements which are U-shaped, the fastener would extend through the tension member and through the upper surface of the bridge element. For a square bridge element, the fastener would extend through the tension member and the bottom surface and/or the top surface of the bridge element. The tension member connected along the bottom surface of the bridge element device allows the bridge elements to be flexible and rolled for transport or storage. The tension of FIG. 4A is a metal strap 16 and the tension device of FIG. 4B is a cable 19. Fastener 18 is a screw which is held in place by a nut 21.
FIG. 5 illustrates an alternative tension member which is a cable 20. Cable 20 is attached to each individual bridge element 12 by a fastener 22. Yet another tension member for connecting the individual bridge elements is a mesh 24 as shown in FIG. 7.
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 FIG. 6 could be placed between the individual bridge elements towards the top of the elements to form the arch. Generally speaking, the length of each element is in the range of about three to fifty feet long, and the width ranging between three inches to ten feet.
Because of the ability to be flexible, the bridge structure can be rolled onto a reel 28 as shown if FIG. 7. Once rolled onto a reel, the bridge structure occupies less space as it is coiled onto the reel and becomes transportable. The distance which an extended bridge structure is capable of spanning is dependent upon the size of the individual elements. Generally speaking, the bridge is adapted to span distances of about ten to two-hundred feet, or more. Preferably, the bridge elements are made of wood, plastic, metal or carbon fiber material where strength and lightweight are required. The fasteners used to attach the tension member to the bridge elements could be screws, bolts, rivets, clamps, hooks or other bonding methods, such as welding or glue.
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 FIG. 7.
As shown if FIG. 8, to span a body of water 32 an end 34 of the bridge can be placed on a pontoon 36 and floated across the water to bank 38. The opposite end of the bridge would then be positioned on bank 40. Referring to FIG. 9 the bridge could be deployed over a ravine 42 by having telescoping rails 44 extending from truck 46 and the bridge unwound and slid across the rails until reaching land. To bridge over water, a bridge made of sealed tubes could be unrolled and floated over the water in any orientation. Once reaching the opposite bank, it could be positioned accordingly. In a configuration where the bridge is floating, it could be pulled from one location on the water to another. This could have useful application in flooded areas. If one or more of the individual bridge elements are damaged, they could be replaced on site.
FIG. 10 illustrates the invention utilized as a shelter structure 50. In this embodiment, the individual elements 52 are held in a much more significant arch by larger inserts between the elements. The arch has a sufficient height that it can accommodate occupants or equipment below the arch or be placed between walls.
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.
Patent Application
20070234490
