Abstract:
A fire fighting apparatus includes a high ground-clearance motorized vehicle having a chassis and rear drive wheels, and a quenching agent tank affixed to the chassis, the quenching agent tank being made of a first tank portion; and a second tank portion located between the first tank portion and the chassis, a width of the second tank portion being greater than a width of the first tank portion, and a distance between a center of mass of the tank and the chassis being as small as possible.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to fire fighting vehicles.  
           [0003]    2. Background of the Invention  
           [0004]    Fire fighting vehicles for use in fighting forest fires, grass fires and other situations involving rough terrain are known. Typically such vehicles are multiple-wheel drive trucks with high-ground clearance in order to permit traversing steep and uneven terrain. However, this high ground clearance necessarily results in a high center of mass and a resultant degradation in vehicle stability. One such known fire truck used, for example, by the U.S. Forest Service, is based upon a military surplus truck which includes a flat bed load carrying surface mounted on the vehicle chassis, and located behind the passenger cab. Such vehicles typically have been retrofit for use as rough-terrain fire fighting vehicles by affixing a rectangular or cylindrical water tank and water pumping equipment directly to the existing flat bed.  
           [0005]    However, such retrofitted configurations have proven unstable in rough and hilly terrain. In particular such vehicles are prone to roll over when moving transverse to a steep slope. The high center of mass of such vehicles also degrades road handling characteristics, particularly when cornering, thus decreasing the maximum speed of the vehicle and potentially increasing fire response times. Further, the high center of mass has limited the practical height of the water tanks in an attempt to improve stability, which results in the undesirable reduction in tank capacity. Still further, visibility rearward from the passenger compartment was often restricted by such tanks, thus rendering the trucks difficult to back and often dangerous when backing.  
           [0006]    It would thus be desirable to provide a rough terrain fire fighting vehicle with improved rollover and road handling stability, while at the same time maintaining or increasing water carrying capacity and while maintaining rearward visibility, a high ground clearance and the ability to negotiate rough terrain.  
         SUMMARY OF THE INVENTION  
         [0007]    The above-shortcomings of the prior art are reduced or eliminated by the fire truck of the present invention.  
           [0008]    In an illustrated embodiment, a fire fighting apparatus is provided that includes a high ground-clearance motorized vehicle having a chassis and at least rear drive wheels, and a quenching agent tank affixed to the chassis, the quenching agent tank being made of a first tank portion; and a second tank portion located between the first tank portion and the chassis, a width of the second tank portion being greater than a width of the first tank portion, and a distance between a center of mass of the tank and the chassis being as small as possible.  
           [0009]    Other features and associated advantages will become apparent with reference with reference to the following detailed description of specific embodiments in connection with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components provided with the invention, will become more readily apparent by referring to the exemplary, and therefore nonlimiting, embodiments illustrated in the drawings. The invention may be better understood by reference to one or more of these drawings in combination with the description presented herein. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale.  
         [0011]    [0011]FIG. 1 is a side plan view of a vehicle accordance with an embodiment of the present invention.  
         [0012]    [0012]FIG. 2 is a rear plan view of the vehicle of FIG. 1.  
         [0013]    [0013]FIG. 3 is a side plan view of the tank assembly used in the vehicle of FIG. 1.  
         [0014]    [0014]FIG. 4 is a rear plan view of the tank assembly of FIG. 3.  
         [0015]    [0015]FIG. 5 is a top plan view of the assembly tank of FIG. 3.  
         [0016]    [0016]FIG. 6. is a partial cross-section of the assembly tank of FIG. 3, in accordance with an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0017]    The fire truck of the present invention addresses the shortcomings of conventional apparatus such as those discussed above. Ground clearance, water carrying capability and vehicle stability are all maximized.  
         [0018]    A representative embodiment of a fire truck  100  in accordance with the present invention is shown in FIG. 1. Truck  100  is based upon a M35 A2 2.5 Ton military surplus vehicle configured in the cargo configuration, and includes many original components. Fire truck  100  includes chassis  101  upon which are mounted a truck engine and drivetrain (not shown), front wheels  102  and rear wheel sets  103 , vehicle fuel tank  104  and passenger compartment  106 . In addition, fire truck  100  includes water tank assembly  107 , including water tank  108 , safety railing  109 , hose reel  111 , and fire hose and filler hose storage  112 . The truck is always driven by all sets of rear wheels  103 , and may also be driven by front wheels  102 , either permanently or selectively, depending on vehicle configuration. Rear wheel sets  103  are preferably dual tire sets. Thus, fire truck  100  is preferably a multiple-wheel drive vehicle, and in one embodiment may be a three-axle, ten-wheel drive vehicle.  
         [0019]    Referring also to the rear plan view of FIG. 2, fire truck  100  also includes a water pump  113 . In the illustrated embodiment, water pump  113  is a gasoline-powered water pump, and included on truck  100  is water pump fuel tank  114 . However, other means of powering water pump  113  would also be acceptable, including, for example electrical power, or power from a power-take-off from the drivetrain of fire truck  100 . Steps  116  are provided to facilitate access to the top of tank  108 , upon which are mounted hose reel  111  and water pump  113 .  
         [0020]    Water pump  113  has two modes of operation. The first is to supply pressurized water from tank  108  to hose  117  as well as to other hoses or water spraying devices as desired for fighting fires. Water may also be supplied to other water distributing devices, such as for example, a water cannon or vehicle-mounted water spray nozzles. In a second mode of operation, water pump  113  is used to draw water through a filler hose from a water source, such as a stream, river, lake or pond, for the purpose of filling tank  108  with water in the field.  
         [0021]    Although unaltered water is the preferred quenching agent for most fire fighting applications, other quenching agents would also be acceptable, including, for example, water mixed with a foaming agent or water mixed with a chemical fire retarding agent. These fire retarding agents may be mixed with the water in tank  108 , or may be injected into the fluid stream as it is pumped from tank  108  by water pump  113 .  
         [0022]    In order to easily accommodate rough terrain, the ground clearance C of fire truck  100  (defined herein as the minimum distance between the rear differential, motor oil pan, or under-chassis skid plates, and the ground) in an exemplary embodiment of the present invention is preferably at least approximately 25 centimeters (10 inches), and even more preferably at least approximately 30 centimeters (12 inches). In accordance with the present invention, tank  108  of tank assembly  107  (the details of which are presented below with references to FIGS.  3 - 6 ) should have a center of mass CG as low as possible, and preferably less than approximately 46 centimeters (18 inches) above chassis  101 . In one exemplary embodiment, the CG of tank  108  is located approximately 34 centimeters (13.5 inches) above the top of the chassis  101 . At the same time, in this exemplary embodiment, tank  108  has a capacity of approximately 5000 liters (1,300 gallons). It should be noted that tank  108  may be mounted directly to chassis  101 . However, in order to minimize the deleterious effects of direct metal-to metal contact it may be desirable to include a spacer between chassis  101  and tank  108 . This spacer may be made of any acceptable material such as wood, an elastomeric material, or any suitable mechanically buffering material.  
         [0023]    In contrast, in one example of a prior art tank of rectangular configuration mounted directly to a flatbed mounted on chassis  101 , a center of mass of the tank is approximately 76 centimeters (30 inches) from the top of chassis  101  and the tank has a carrying capacity of 3,800 liters (1,000 gallons). In another example of a prior art tank of rectangular configuration mounted directly to a flatbed mounted on chassis  101 , a center of mass of the tank is approximately 56 centimeters (22 inches) from the top of chassis  101  and the tank has a carrying capacity of 2,850 liters (750 gallons). In yet another prior art example, a tank of cylindrical configuration is mounted directly to a flatbed mounted on chassis  101 , a center of mass of the tank is approximately 61 centimeters (24 inches) from the top of chassis  101  and the tank has a carrying capacity of 2,850 liters (750 gallons). In addition, the top of each of these prior tanks in these prior art trucks obstructs the reward view from the passenger compartment.  
         [0024]    Thus, it may be seen that tank  108  of assembly  107  of fire truck  100 , in accordance with the presently claimed invention, exhibits a much lower center of mass resulting in improved road stability and resistance to rollovers on rough sloping terrain, while at the same time greatly increasing water tank capacity. In addition, as may be seen with reference to FIGS. 1 and 2, tank  108  does not obstruct the rearward view from passenger compartment  106  through window  118  thus improving the safety of fire truck  100  when backing.  
         [0025]    Turning now to FIGS.  3 - 6 , the details of water tank assembly  107  are presented. Water tank assembly  107  includes water tank  108  to which is attached safety railing  109  and steps  116 . Water tank  108  is formed to decrease the center of mass of the tank, while at the same time increasing overall capacity, and in the illustrated embodiment, is formed of upper tank portion  119  and lower tank portion  121 . Upper tank portion  119  has a narrower width than lower tank portion  121 , thus forming walkways  122  on top of lower tank portion  121 . Walkways  122  permit fire fighting personnel to walk around and along the sides of the upper tank portion  119  of water tank  108  providing firefighting stations permitting on all sides of truck  100  access to fires on all sides of truck  100 , while the personal remain on fire truck  100  and are retained by safety railing  109 . In addition, formed integral with lower tank portion  121  are wheel wells  123  which conform to rear drive wheel sets  103  when tank assembly  107  is mounted on chassis  101  of fire truck  100 . Wheel wells  123  permit the bottom of tank  108  to be mounted as closely as possible to the top of chassis  101  without interfering with the rotation or vertical movement of rear drive wheel sets  103 .  
         [0026]    In the illustrated and therefore nonlimiting example, fire truck  100  is fabricated from a pre-existing military surplus vehicle. During such fabrication, the flat bed originally included on the vehicle and mounted on chassis  101  is removed, and is replaced by tank assembly  107 , thus permitting tank  108  to be mounted as closely as possible to the top of chassis  101 .  
         [0027]    The configuration of water tank  108  with upper tank portion  119  and lower tank portion  121 , and the inclusion of wheel wells  123  within lower tank portion  121  permit water tank  108  to be located physically lower than prior approaches, thus lowering the center of mass greatly improving truck stability. At the same time, the carrying capacity of tank  108  is increased remarkably. Further, the mounting of tank assembly  107  directly to chassis  101  of fire truck  100 , with or without spacers, further lowers the center of mass and further promotes truck stability.  
         [0028]    In the illustrated embodiment, lower tank portion  121  is formed with step portion  124  which serves several purposes. First, it provides additional tank capacity at a location very close to chassis  101  thus further promoting the lowering of center of mass CG of tank  108 . Second, it provides a step transition between step  116  and walkway  122 . And third, it provides a mounting surface for hose reel  111 , water pump  113 , and water pump fuel tank  114 . (See also FIGS. 1 and 2.) Angle brackets  126  are welded to step portion  124  and are provided for mounting hose reel  111  and water pump  113 .  
         [0029]    To further promote stability of truck  100 , tank  108  is provided with internal baffles  127 . These are shown in more detail with reference to FIG. 6. Also provided on tank  108  is tank access hatch  128  which may be used for filling tank  108  without use of pump  113 , and hose retainers  129 . In addition, the back of tank assembly  107  is provided with a non-slip surface  131 , which may be formed of an expanded metal.  
         [0030]    Referring now to FIG. 6, the baffle structure within tank  108  is presented. FIG. 6 is a partial cross section view take through section  6 - 6  of FIG. 4. Tank  108  of tank assembly  107  includes a baffling structure in order to minimize liquid movement while fire truck  100  is accelerating, decelerating or turning. The baffling structure includes baffles  127  which are spaced apart to minimize fluid sloshing within tank  108 . In the exemplary embodiment, baffles  127  are space longitudinally and also laterally within tank  108 . Baffles  127  have holes therein to permit water flow during pumping and filling operations, while at the same time providing the described baffling function during acceleration and deceleration.  
         [0031]    Tank  108  is preferably constructed of welded metal plates, and is coated with a corrosion resistant coating, such as epoxy paint or the like. The interior of tank  108  also preferably has a corrosion resistant coating such as paint, or galvanization. In addition, walkable surfaces including walkways  122  and filler hose storage section  112 , are preferably non-skid surfaces for safety.  
         [0032]    With the benefit of the present disclosure, those having skill in the art will comprehend that apparatus claimed herein and described above may be modified and applied to a number of additional, different applications, achieving the same or a similar result. The claims attached hereto cover all such modifications that-fall within the scope and spirit of this disclosure. For example, although the description of this disclosure focuses upon embodiments well suited for use as modifications to preexisting military surplus trucks, those of ordinary skill in the art having the benefit of this disclosure will recognize that the inventions described herein may be implemented in new vehicles, including vehicles other than trucks, or as modifications to other types of preexisting vehicles.