Abstract:
An amphibious vehicle having inflatable pontoons disposed in recesses formed in the vehicle body. The inflatable pontoons retract into the recesses when deflated to reduce the overall width of the vehicle to below the maximum allowable width for a road vehicle. The inflatable pontoons extend when inflated to beyond the maximum allowable width for road vehicles, thereby improving the stability of the vehicle when it is operated in water. The inside surfaces of the recesses provide support for transferring the uplift force generated by the pontoons to the vehicle body when in water. An elastic member may be used to retract the deflated pontoons into the recess. Decorative doors covering the recesses are forced open by the inflating pontoons to a position above the water line.

Description:
[0001]    This application claims benefit of U.S. provisional patent application No. 60/221,427, filed on Jul. 28, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to an amphibious vehicle capable of operation on land and in the water.  
         BACKGROUND OF THE INVENTION  
         [0003]    Amphibious vehicles adopting pontoons and other means for floatation and stability in the water, as well as inflatable pontoons adapted for use with various water borne structures, are known in the prior art. Prior art amphibious vehicles are generally designed to ride low in the water to inhibit capsizing. Such vehicles are typically operated at low speeds as further precaution against excessive rolling or capsizing. Other prior art vehicles, such as work boats that are not amphibious, have floatation elements which are permanently inflated. Such flotation elements extend outwardly by moveable arms for additional stability during periods of stationary work. This particular design is not well suited for use with an amphibious vehicle because the mechanism securing the floatation elements may fail due to the loads resulting from waves and vehicle movement.  
           [0004]    Various means are employed in the prior art for floatation of amphibious vehicles.  
           [0005]    U.S. Pat. No. 5,868,093 discloses an amphibious vehicle having disposed within its body cavity a plurality of hollow cells for floatation. Buoyancy tanks that articulate between an operative and inoperative position by piston and cylinder means are disclosed in U.S. Pat. No. 5,315,950. In the inoperative position the tanks are disposed parallel to one another above the roof of the vehicle. Similarly, U.S. Pat.  
           [0006]    No. 4,802,433 discloses an amphibious vehicle having pontoons that articulate between a position for water travel and a storage position for road travel, which is on top of the vehicle. Both the &#39;950 and &#39;433 patents pertain to recreational vehicles that presumably make use of federal, state and local highways, roads and streets. Thus, the design of these vehicles makes it necessary to employ fairly elaborate mechanisms to stow the pontoons in a position that complies with vehicle width restrictions imposed by the various governmental bodies responsible for those pathways. U.S. Pat. No. 5,687,669 discloses a vehicle employing pontoon assemblies pivotally coupled to a vehicle&#39;s frame so that the pontoons may be stowed within the width of the frame for highway, road and street use. Wheels are disposed on each pontoon assembly for land use.  
           [0007]    Float means are disclosed by U.S. Pat. No. 5,727,494 for a cockpit body. The float means may be a plurality of retractable pontoons, or of a plurality of longitudinally extending hulls integrally formed within the vehicle. Such float means keep the vehicle afloat and provide stability during marine operation. U.S. Pat. No. 4,459,932 discloses an amphibious vehicle employing inflatable members disposed in the front, rear and one side of the vehicle, with another inflatable element directly beneath the chassis adapted to serve as a float for the vehicle. Resilient traction elements are also disclosed that are disposed inside and around the inflatable elements. Also in the prior art, a buoyant boat hull having substantially horizontal cylinder recesses along its sides for receiving a pair of helical augers is disclosed by U.S. Pat. No. 5,203,274. These recesses are specially adapted to confine water between the screw threads and project it directly to the rear of the vehicle for more efficient forward thrust.  
           [0008]    Another prior art invention disclosed in U.S. Pat. No. 5,875,730 discloses a device for attaching inflatable pontoons to rigid keels. An elongated, substantially arcuate member conforming substantially to the circumference of a pontoon is affixed to a rigid keel. The member is preferably made of a weldable metal such as aluminum and is welded to the keel for receiving the pontoon.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention is an amphibious vehicle having inflatable pontoons adapted for use as a passenger vehicle on both land and in water. The vehicle may be used, for example, for transporting tourists in areas where the touring route includes travel over land and in the water for the passengers&#39;optimal viewing and educational enjoyment. As such, it is important for the vehicle to make quick transitions between land and water to minimize delay, which reduces the risk of passenger discontent from having to wait for an operator to make mechanical or other adjustments to the vehicle that passengers may view as being unreasonably lengthy.  
           [0010]    The present invention is adapted for use on public highways, roads and streets by ensuring that the vehicle complies with vehicle width restrictions for use on these venues. For use in the water, the vehicle employs inflatable pontoons that operate with minimal delay and which extend the width of the vehicle while in the water to provide greater vehicle stability to reduce the risk of excessive rolling or capsizing. In one embodiment of the present invention, the vehicle includes one or more pontoons disposed in a substantially horizontal configuration along each side of the vehicle&#39;s main body. The pontoons are securely disposed within recessed cavities formed within the main body so that when they are deflated they may be withdrawn within each cavity so that the width of the vehicle complies with vehicle width restrictions for use on highways, roads and streets. In one embodiment of the present invention, the means for securing a pontoon within a recessed cavity includes a fastening means, such as Velcro, a clamping means such as clamps or bolts affixed to the main body along the upper and lower edges of the cavity that grasp center seam flaps extending longitudinally along the exterior of the pontoon, and a substantially elastic member or members that are affixed to the main body and extend around the exterior of the pontoon. The substantially elastic member not only helps to secure the pontoon within the recessed cavity, but due to its elastic properties, it also ensures the pontoon is fully withdrawn within the confines of the cavity when the pontoon is deflated to prevent the pontoon from drooping downwardly. The elastic member stretches outward when the inflatable pontoon expands and contracts when the inflatable pontoon is deflated to pull the inflatable pontoon within the recessed cavity. It also provides protection for the pontoon against external physical damage. With the pontoon secured within the cavity, a hinged decorative door may be closed to cover the pontoon for aesthetic purposes and to protect it from damage due to weathering. Further, the decorative door may be pushed up out of the water by the inflatable pontoon when the inflatable pontoon is inflated and will close over the inflatable pontoon when deflated by means of a spring loaded hinge. Alternatively, the door may be opened and closed manually.  
           [0011]    The inflatable pontoons of the present invention may be cylindrical tubes which may be of varying diameters and lengths depending on the design of the vehicle and conditions within which the vehicle will be used. In one embodiment of the present invention, the pontoons are disposed on each side of the vehicle between the front and rear wheels. This placement provides optimum stability for the vehicle shown in the Figures while the vehicle is in the water. Other placements may be employed as a function of vehicle design and operational requirements. The pontoons are inflated and deflated by means of conventional air generators such as pressurized air tanks or blowers. The air generators are connected to piping having valves and pressure regulators to fill each pontoon to the desired pressure, which is typically done just prior to the vehicle entering the water. The air generators are also used to deflate the pontoons for use on land by switching or reversing the position of valves. Multiple volumes of inflatable pontoons and multiple air supplies may be provided for safety to prevent sinking in the event of a component failure. Each pontoon may also include a plurality of internal chambers to prevent total deflation of a pontoon in the event of damage. In one embodiment of the present invention, each pontoon has four discrete internal chambers that are air tight so that if one deflates the others will not. Further, the ends of each pontoon may be tapered to facilitate movement of the vehicle through the water with reduced water friction. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The features and advantages of the present invention will become apparent from the following detailed description of the invention when read with the accompanying drawings in which:  
         [0013]    [0013]FIG. 1 illustrates a side view of an amphibious vehicle having an inflatable pontoon disposed within one of its sides.  
         [0014]    [0014]FIG. 2 illustrates a top view of an amphibious vehicle having inflatable pontoons in their inflated state disposed within each of its sides.  
         [0015]    [0015]FIG. 3 illustrates a top view of an amphibious vehicle having inflatable pontoons in their deflated state disposed within each of its sides.  
         [0016]    [0016]FIG. 4 illustrates a front view of an amphibious vehicle having inflatable pontoons in their inflated state disposed within each of its sides.  
         [0017]    [0017]FIG. 5 illustrates a front view of an amphibious vehicle having inflatable pontoons in their deflated state disposed within each of its sides.  
         [0018]    [0018]FIG. 6 illustrates a cross section of an inflatable pontoon in its inflated state disposed within a recessed cavity, means for securing the pontoon within the cavity, and a decorative door for covering the pontoon in its deflated state.  
         [0019]    [0019]FIG. 7 illustrates a schematic representation of air generators and valves providing for the inflation and deflation of the pontoons. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    [0020]FIG. 1 illustrates an amphibious vehicle  10  having a main body portion  12  and an inflatable member used for at least partial floating support of the vehicle  10  when it is operated in water. The inflatable member illustrated in FIG. 1 is inflatable pontoon  14 , although one skilled in the art can appreciate that the inflatable member may take other shapes, sizes and locations on the vehicle. Inflatable pontoon  14  is horizontally disposed between wheels  16 . Amphibious vehicle  10  employs conventional means known in the art for making it water tight, providing locomotive power and a drive train, as well as necessary electrical systems, and steering mechanisms. Vehicle  10  also includes means for inflating and deflating the pontoons  14 , as will be described more fully below. Inflatable pontoon  14  is constructed of material known in the art, such as rubber, suitable for a high number of inflation and deflation cycles and sufficiently durable to withstand impact loads typically encountered during use in the water. In one embodiment, both ends  18  of inflatable pontoon  14  are tapered to facilitate movement through water with reduced water friction. Alternatively, only one end  18  may be tapered, preferably the end toward the front of the vehicle, or neither may be tapered.  
         [0021]    [0021]FIG. 2 illustrates a top view of vehicle  10  having one inflatable pontoon  14  disposed in each of a first side  15  and a second side  17  of the main body portion  12 . In this figure, inflatable pontoons  14  are shown in their fully inflated position. In one embodiment, the total width of vehicle  10  is 132 inches when inflatable pontoons  14  are in their fully inflated state. This maximum width is selected to provide a high level of stability to vehicle  10  when maneuvering in the water. In alternative embodiments, vehicle  10  may be configured for widths greater or lesser than 132 inches as a function of vehicle design and operational requirements.  
         [0022]    [0022]FIG. 3 illustrates a top view of amphibious vehicle  10  having inflatable pontoons  14  in their deflated state and retracted within the main body portion  12  so the vehicle  10  complies with any relevant statutory vehicle width restriction for use on highways, roads and streets. In one embodiment in compliance with current Federal Department of Transportation regulations, vehicle  10  is less than or equal to 102 inches in total width. Alternatively, vehicle  10  may be adapted to conform to other width restrictions, including other statutory limitations as may be applied from time to time. Importantly, the overall width of the vehicle with the pontoon  14  in its deflated condition is less than the maximum width of the vehicle with the pontoon  14  inflated. Thus the inflated pontoon  14  extends for additional stability in the water when inflated and retracts to facilitate operation on dry land when deflated.  
         [0023]    [0023]FIG. 4 illustrates a front view of amphibious vehicle  10  having inflatable pontoon  14  having a tapered end  18  disposed in each side of the main body portion  12 . FIG. 5 illustrates a front view of vehicle  10  with inflatable pontoons  14  in their deflated state and retracted within main body portion  12 .  
         [0024]    [0024]FIG. 6 illustrates a cross section of main body portion  12  having an inflatable pontoon  14  disposed within a recessed cavity  20  formed within main body portion  12 . In one embodiment, recessed cavity  20  is defined by a substantially arcuate inner surface  22  that spans at least a portion of the length of inflatable pontoon  14  and has a substantially constant radius of curvature. In another embodiment, the end portions of recessed cavity  20 , not shown, may be tapered to conform to the tapered ends  18  of inflatable pontoons  14 . The arcuate inner surface  22  serves to capture the pontoon  14  when the main body portion  12  is immersed in water, thereby transferring the uplift force created by the buoyancy of the pontoon  14  to the body portion  12 . The inner surface  22  may be included from a horizontal axis at its top most end so that any upward force exerted by pontoon  14  tends to force the pontoon  14  into the depth of the recess  20 . By capturing the pontoon  14  within the recessed cavity  20 , the mechanical connection between these components can be greatly simplified and of much lighter weight than prior art arm-like connections. Because there will be forces applied to and by the pontoon  14  in all directions, there remains a need for a supplemental means for securing the pontoon  14  within the cavity  20 . The means for securing inflatable pontoon  14  within recessed cavity  20  may include a fastening means  24  such as Velcro®, or other suitable hook and loop type fasteners, or temporary adhesives, a clamping means such as a plurality of clamps  26 , or other suitable devices such as bolts, and/or an elastic member  28 . Fastening means  24  may span all or substantially all of the length of recessed cavity  20  and inflatable pontoon  14  or it may be a series of segments disposed apart at predetermined distances depending on the operational requirements of amphibious vehicle  10  and loads anticipated to be received by inflatable pontoons  14  due to water impact. A first portion  25  of fastening means  24  is affixed to the inner surface  22  of recessed cavity  20  and a corresponding second portion  27  of fastening means  24  is affixed to the outer surface of inflatable pontoon  14  so that when inflatable pontoon  14  is received by recessed cavity  20  the first portion  25  and second portion  27  adhere to each other. Clamps  26  are securely affixed to main body portion  12  and are adapted to receive flaps  30  that form the center seams of inflatable pontoons  14 , which span their length in one embodiment. Flaps  30  may be seamlessly integrated as part of inflatable pontoons  14  by conventional means such as an extrusion process known in the art. Clamps  26  are disposed along the upper  32  and lower  34  edges of recessed cavity  20  at predetermined distances depending on the operational requirements of amphibious vehicle  10  and loads anticipated to be received by inflatable pontoons  14  due to water impact. Elastic member  28  is made of material known in the art suitable for a high volume of inflation and deflation cycles and sufficiently durable to withstand water and debris impact loads typically encountered during use in the water. In one embodiment, elastic member  28  may be a series of straps disposed along the length of recessed cavity  20  or in another embodiment it may span the entire length of recessed cavity  20  and inflatable pontoons  14 . At least one end  36  of each elastic member  28  is detachably affixed by conventional means to main body portion  12  so that easy access may be gained to inflatable pontoons  14  and recessed cavity  20  and so that elastic member  28  may be repaired or replaced.  
         [0025]    Each recessed cavity  20  is adapted to receive the inflated pontoon so that the pontoon abuts snugly against the inner surface  22 . This relationship provides a very strong interface capability between the pontoon and the main body of the vehicle, which minimizes displacement of the pontoon resulting from wave and impact loads. It also promotes the dissipation of such loads across the main body rather than such loads being absorbed almost entirely by a pontoon attachment mechanism. In one embodiment of the present invention, the inner surface of each cavity forms at least a semi-circle that is at least equal to one-half the circumference of the pontoon being received, with the pontoon being approximately 30 inches in diameter and at least one-half of it being contained within the recessed cavity  20 . The inner surface  22  is disposed at least in part above the inflatable pontoon  14  for receiving the uplift force created by the buoyancy of the pontoon when the amphibious vehicle is operated in water. This relationship provides the structural support needed for the pontoons to remain attached to the main body while under extreme upward pressure. The recessed cavity feature of the present invention provides a significant advantage over prior art configurations that have pontoons extended away from the main body of a vehicle by rigid support means and those that have pontoons affixed directly to the exterior of the vehicle. Those configurations result in the pontoons absorbing a higher degree of wave impact loads than those received by the configuration of the present invention, which make those prior art designs more susceptible to mechanical damage. This feature also provides the capability for the vehicle to quickly vary its width for transitioning between land use and water use. As the pontoon  14  is inflated, it grows in size horizontally, thereby increasing the width of the vehicle  10  to perhaps a size greater than the legal limit for use on highways. Accordingly, the present invention not only provides a mechanically secure apparatus for attaching an inflatable pontoon  14  to an amphibious vehicle  10 , but also provides a method for increasing the width of the vehicle to increase its waterborne stability to a width that is greater than a width that is permitted for highway vehicle operation.  
         [0026]    [0026]FIG. 6 also illustrates a decorative door  38  that is pivotally attached by hinge  40  to main body portion  12  so that decorative door  38  may be opened when inflatable pontoons  14  are in their inflated state and closed when they are in their deflated state to provide a decorative cover over them and to protect them from damage due to weathering and other causes. Decorative door  38  may be moved simply by the pressure exerted against it by pontoon  14 , or it may be separately powered or manually moved. The door  38  is moved above a waterline of the vehicle  10  by the inflatable pontoon  14  when it is in the inflated condition to avoid additional drag as the vehicle is propelled through the water.  
         [0027]    [0027]FIG. 7 illustrates a schematic representation of a means  42  for supplying air to and withdrawing air from the inflatable pontoons  14  for inflation and deflation. It also illustrates one embodiment of the present invention where four internal chambers  19  are integral to inflatable pontoons  14 . Other embodiments may include more or less internal chambers  19  as a function of vehicle design and operational requirements. Compressed air is supplied by compressor  44  through receivers  46  to each respective chamber  19  via high pressure inflation valve  48  or via low pressure inflation valve  50  through pressure reducer  52 . The compressed air may be provided directly from the compressor  44  without the benefit of accumulation in the receivers  46 , although the inflation time may be increased. Individual chamber inflation valves  54  and deflation valves  56  are provided. Relief valves  58  may be provided for each chamber  19 , either attached directly to the pressure chamber  19  or at an appropriate location within the associated piping  60 . Exhaust from the chambers  19  may be provided to the intake of the compressor  44  through valve  62  or may be vented directly to atmosphere  64 . Valve  62 , compressor  44 , valves  56  and other associated piping and valves form a means for returning compressed gas from the inflatable pontoons  14  to the receivers  46 , thereby reducing the need to draw atmospheric gas into the system  42 , and increasing the response time of the system for rapid inflation and deflation of the chambers  19 . Compressor  44  may also draw atmospheric air through valve  64 . A control system (not shown) is provided to control the operation of these various components to achieve a high degree of control over the inflation and deflation of the inflatable pontoons  14  for rapid deployment/withdrawal and for safe, redundant operation.  
         [0028]    While the preferred embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those of skill in the art without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.