Abstract:
A universal aircraft mule having a rollable and steerable frame and a load carrying cradle configured for removably supporting and carrying an auxiliary. The frame tiltably and liftably supports the cradle with a lift assembly. The lift assembly raises and lowers the cradle in relation to the frame and tilts the cradle in relation to the frame. The cradle also allows an auxiliary to be skewed within the cradle to facilitate loading and unloading of the auxiliary.

Description:
TECHNICAL FIELD 
     The present invention is generally related to barrows, carts, and wheeled transports and more particularly related to mules designed for transporting specialized auxiliary fuel tanks and the like to and from a specific aircraft. 
     BACKGROUND OF THE INVENTION 
     Aircraft, especially military aircraft, are often equipped with auxiliaries. Such auxiliaries include fuel tanks (drop tanks), ordinance, drone, sensor pods, storage, and the like. Generally, such auxiliaries are configured to be carried on the fuselage belly or the underside of the wings. It will be appreciated that different aircraft have different dimensions and auxiliary needs. Thus, it is known in the art to provide a specialized cart for use in transporting and facilitating the installation/removal of a particular auxiliary on a particular aircraft. 
     As aircraft are configured for different missions auxiliaries designed for a particular aircraft and a particular mission are typically removed from storage and transported to an aircraft via a specially configured mule. Such a specially configured mule is designed to carry a single mission specific auxiliary for fitment at a particular location on a particular model of aircraft. 
     In an operating theater it is not uncommon for a diverse group of aircraft including different models of aircraft designed and configured for different missions to be operated from a single location. This requires the storage of various aircraft, various auxiliaries, and various mules. Additionally, personnel trained in aircraft configuration techniques for each aircraft, auxiliary, and mule must be available. This requires additional storage and operating space, theater equipment transport effort and logistics, personnel and training, and planning. 
     SUMMARY OF THE INVENTION 
     The present invention provides a universal aircraft mule for readily and rapidly universally transporting, removing and installing auxiliaries of different sizes and configurations at various locations on different aircraft. The universal aircraft mule may lift and transport auxiliary loads with different masses, centers of gravity, lengths, and widths. The universal aircraft mule is capable of operating in small and confined spaces without damaging aircraft components and without unduly endangering personnel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a preferred embodiment of the universal aircraft mule of the present invention carrying a 600 gallon auxiliary fuel tank (A-10 Thunderbolt, Sargent-Fletcher belly tank) in a mid-height lifted position; 
         FIG. 2  is a side elevation of a preferred embodiment of the universal aircraft mule of the present invention carrying a 600 gallon auxiliary fuel tank in a partially tilted and substantially fully lifted position; 
         FIG. 3  is a perspective view of a preferred embodiment of the universal aircraft mule of the present invention carrying an auxiliary wing fuel tank (F-15 Eagle) in an aligned partially lifted position; 
         FIG. 4  is a top plan view of a preferred embodiment of the universal aircraft mule of the present invention illustrating the steering assembly, lifting and tilting mechanisms, the cradle and skewing assembly, and the hydraulic system; 
         FIG. 5  is a perspective top view of a preferred embodiment of the universal aircraft mule of the present invention in a partially lifted position; 
         FIG. 6  is a perspective bottom view of a preferred embodiment of the universal aircraft mule of the present invention illustrating the non-sparking skid, steering assembly, and the mule&#39;s flat low profile and lifting assembly for providing a near ground height to over approximately 1.5 meter lift envelope; 
         FIG. 7  is a side elevational view of a preferred embodiment of the universal aircraft mule of the present invention showing the cradle and lift assembly operating range; 
         FIG. 8  is a side elevational view of a preferred embodiment of the universal aircraft mule of the present invention showing the lift assembly in various positions; 
         FIG. 9  is a top plan view of a preferred embodiment of the universal aircraft mule of the present invention showing a 600 gallon drop tank in broken lines where the tank is in a fully lowered non-skewed position; 
         FIG. 10  is a top plan view of a preferred embodiment of the universal aircraft mule of the present invention showing a 600 gallon drop tank in broken lines where the tank is a fully lowered skewed position; 
         FIGS. 11A ,  11 B, and  11 C are perspective detailed views of the cradle and skew assembly of a preferred embodiment of the universal aircraft mule of the present invention; 
         FIGS. 12A and 12B  are perspective detailed views of the non-rotation stabilizer of the cradle of a preferred embodiment of the universal aircraft mule of the present invention; 
         FIG. 13  is a detailed perspective view of the hydraulic lift and tilt assembly of a preferred embodiment of the universal aircraft mule of the present invention; 
         FIG. 14  is a detailed perspective view of steering a parking brake assembly of a preferred embodiment of the universal aircraft mule of the present invention; 
         FIG. 15  is a perspective view of three of the universal aircraft mules of the present invention in a stacked for storage/shipping configuration; 
         FIG. 16  is a frontal perspective view of the universal aircraft mule of the present invention wherein an auxiliary wing tank is being installed on an F-16 Fighting Falcon; 
         FIG. 17  is a perspective view of the universal aircraft mule installing/removing a belly drop tank from an F-15; 
         FIG. 18  is a front perspective view of the universal aircraft mule illustrating the low end of the mule&#39;s cradle operating envelope; 
         FIG. 19  is a side perspective view of the starboard side of the U-frame of a presently preferred embodiment; 
         FIG. 20  is a top perspective view of the transport height locking device, pump handle pressure release valve, tilt direction control, tilt pump, and toe-activated descent controller; 
         FIG. 21  is a top perspective view illustrating the tilt direction and tilt amount indicator of a presently preferred embodiment of the present invention; 
         FIG. 22  is a top perspective view of the front of a preferred embodiment illustrating the lift reservoir and the counter-balance; 
         FIG. 23  is a diagrammatic perspective view of the system of the present invention illustrating a universal aircraft mule, auxiliary storage facility and mule guide; 
         FIG. 24  is a side elevational view of the system of the present invention in a ready to load configuration illustrating the sequential vertical storage facility with auxiliary selection, mule guide and tilt-to-load feature; 
         FIG. 25  is a side elevational view of the system of the present invention in a loading position illustrating the sequential vertical storage facility with auxiliary selection, mule guide and tilt-to-load feature; 
         FIG. 26  is a side elevational view of the system of the present invention in a loaded carrying configuration illustrating the sequential vertical storage facility with auxiliary selection, mule guide and tilt-to-load feature; 
         FIG. 27  is a side perspective view of three stacked mules (four may be safely transported) on a 463L pallet; 
         FIG. 28  is a schematic diagram of the lifting (first) and tilting (second) hydraulic systems of a preferred embodiment of the present invention; and 
         FIG. 29  is a flow diagram of operation of the load/unload logic/sequence of the presently preferred embodiment of the system of the present invention. 
       
         
           
                 
               
                 
                 
                 
                 
               
             
                 
                     
                 
                 
                   Reference Numeral Key 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                     
                     
                   universal aircraft mule 100 
                     
                 
                 
                     
                     
                   mechanized storage assembly 102 
                     
                 
                 
                     
                     
                   aircraft tank 104 
                     
                 
                 
                     
                     
                   rollable frame 106 
                     
                 
                 
                     
                     
                   non-sparking skid plate 108 
                     
                 
                 
                     
                     
                   pair of wheels 110 and 112 
                     
                 
                 
                     
                     
                   pair of axles 114 and 116 
                     
                 
                 
                     
                     
                   steering arm 118 
                     
                 
                 
                     
                     
                   tie rod 120 
                     
                 
                 
                     
                     
                   steerable tow bar 122 
                     
                 
                 
                     
                     
                   tire 124 
                     
                 
                 
                     
                     
                   split rim 126 
                     
                 
                 
                     
                     
                   parking brake assembly 128 
                     
                 
                 
                     
                     
                   brake plate 130 
                     
                 
                 
                     
                     
                   spring-loaded pin 132 
                     
                 
                 
                     
                     
                   lateral floating carriage 134 
                     
                 
                 
                     
                     
                   lift linkage 136 
                     
                 
                 
                     
                     
                   pivotable connections 138 
                     
                 
                 
                     
                     
                   first hydraulic cylinder 140 
                     
                 
                 
                     
                     
                   aft port lifting bar 142 
                     
                 
                 
                     
                     
                   aft starboard lifting bar 144 
                     
                 
                 
                     
                     
                   second hydraulic cylinder 146 
                     
                 
                 
                     
                     
                   fore port tilting bar 148 
                     
                 
                 
                     
                     
                   fore starboard tilting bar 150 
                     
                 
                 
                     
                     
                   pump bar 152 
                     
                 
                 
                     
                     
                   central hydraulic reservoir 154 
                     
                 
                 
                     
                     
                   fluid level indicator 156 
                     
                 
                 
                     
                     
                   torsional load stabilizer 158 
                     
                 
                 
                     
                     
                   anti-rotation stabilizers 160 
                     
                 
                 
                     
                     
                   tank metering valve 162 
                     
                 
                 
                     
                     
                   pallet 164 
                     
                 
                 
                     
                     
                   transport height locking device 166 
                     
                 
                 
                     
                     
                   cradle 168 
                     
                 
                 
                     
                     
                   mule guide 170 
                     
                 
                 
                     
                     
                   tilt indicator 172 
                     
                 
                 
                     
                     
                   cradle spacer 174 
                     
                 
                 
                     
                     
                   stabilizer slots 176 
                     
                 
                 
                     
                     
                   tilt hydraulic reservoir 180 
                     
                 
                 
                     
                     
                   counter balance 182 
                     
                 
                 
                     
                     
                   strap retention pin 184 
                     
                 
                 
                     
                     
                   cradle spacer lock 186 
                     
                 
                 
                     
                     
                   load recess 188 
                     
                 
                 
                     
                     
                   tilt direction control 190 
                     
                 
                 
                     
                     
                   descent rate controller 192 
                     
                 
                 
                     
                     
                   pivot bearings 194 
                     
                 
                 
                     
                     
                   pivot slots 196 
                     
                 
                 
                     
                     
                   pressure relief valve 198 
                     
                 
                 
                     
                     
                   second hydraulic system (tilting) 200 
                     
                 
                 
                     
                     
                   tilt cylinder 202 
                     
                 
                 
                     
                     
                   first and second counter balance 204, 206 
                     
                 
                 
                     
                     
                   first and second gauge isolator 208, 210 
                     
                 
                 
                     
                     
                   first hand pump 252  
                     
                 
                 
                     
                     
                   second hand pump 254 
                     
                 
                 
                     
                     
                   first hydraulic system (lifting) 300 
                     
                 
                 
                     
                     
                   lifting cylinder 302 
                     
                 
                 
                     
                     
                   velocity fuse 304 
                     
                 
                 
                     
                     
                   first and second compensators 306, 308 
                     
                 
                 
                     
                     
                   first lift hand pump 310 
                     
                 
                 
                     
                     
                   second lift hand pump 312 
                     
                 
                 
                     
                     
                   first and second lift gauge isolators 314, 316 
                 
                 
                     
                     
                 
               
            
           
         
       
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention provides a universal aircraft mule and system for loading/unloading and storing auxiliaries, which may be utilized for multiple aircraft and multiple auxiliaries. 
     Referring now to  FIGS. 1 through 29 , a universal aircraft mule  100  is described. The universal aircraft mule  100  may be utilized for both lifting and tilting an auxiliary wing and/or an auxiliary fuselage tank, and for moving and positioning the auxiliary wing/auxiliary fuselage tank for storage and/or for mounting on the body of an aircraft. For example, the universal aircraft mule  100  may be utilized in an aircraft component storage facility. The storage facility may include a device, such as a mechanized storage assembly  102 , or the like, for sequentially presenting an auxiliary wing and/or an auxiliary fuselage tank to the universal aircraft mule  100 . The universal aircraft mule  100  may include a cradle  168  for lifting and pointing an aircraft tank  104  supported by the cradle  168 . The aircraft tank  104  may be pointed in a direction (e.g., horizontal) for receiving by an aircraft having a structure configured for removably receiving the aircraft tank  104 . 
     The universal aircraft mule  100  includes a rollable frame  106 . In embodiments, the rollable frame  106  includes a non-sparking skid plate  108 . For example, the non-sparking skid plate  108  may include one or more composite friction pads for non-sparking engagement with a paved surface supporting the rollable frame  106 . A paved surface may include an asphalt surface, a concrete surface, or the like. The rollable frame  106  is movably steerable in both a first direction (e.g., forwards) and a second direction opposing the first direction (e.g., backwards). 
     The universal aircraft mule  100  includes a steering mechanism attached to the rollable frame  106  for movably steering the frame. In embodiments, the steering mechanism may include a pair of wheels  110  and  112  and a pair of axles  114  and  116 . Each wheel of the steering mechanism is rotationally connected to the rollable frame  106  via one of the axles. Further, each wheel is connected to a steering arm  118  via a tie rod  120 . The steering arm may be coupled with a tow bar (e.g., steerable tow bar  122 ) for turning, pushing, and/or pulling the universal aircraft mule  100 . In embodiments, the steerable tow bar  122  may be fabricated from a strong, light-weight material, such as aluminum, a composite material, or another material, such as an alloy with a high strength-to-weight ratio. Each wheel may include a solid rubber tire  124  and a split rim  126 . 
     The universal aircraft mule  100  may also include a parking brake assembly  128 . The parking brake assembly  128  may be associated with one or more of the wheels (e.g., wheel  112 ). In embodiments, the parking brake assembly  128  may include a brake plate  130  associated with wheel  112  and a spring loaded pin  132  lockingly engageable with the brake plate  130 . Thus, the spring loaded pin  132  may be engaged with the brake plate  130  for locking the wheel  112  in place and preventing unwanted movement of the universal aircraft mule  100 . 
     The universal aircraft mule  100  includes a lift assembly attached to the rollable frame  106 . The lift assembly includes a cradle  168  having a first side, a second side, a front, and a back. The cradle  168  is operably attached to the lift assembly and configured for supporting an auxiliary fuel tank, such as aircraft tank  104 . For example, the cradle  168  may include a lateral floating carriage  134  connected to the rollable frame  106  and supported by a lift linkage  136 . In embodiments, the lift linkage  136  may be generally parallelogram-shaped. The lift linkage  136  of the lifting mechanism may be pivotally attached to the rollable frame  106  and positioned aft (i.e., behind) of the first wheel  110  and the second wheel  112 . In embodiments, pivotable connections  138  may include bronze bearings and/or ball bearings. 
     For instance, the lift linkage  136  may include a first hydraulic cylinder  140  pivotally driving an aft port lifting bar  142  and an opposing aft starboard lifting bar  144 . The aft port lifting bar  142  and the aft starboard lifting bar  144  are pivotably connected at aft positions to the first and second sides of the lateral floating carriage  134 . The first hydraulic cylinder  140  is included with a first user operable hydraulic system for raising and lowering the cradle  168  between a first generally horizontal plane occupied by the rollable frame  106  and a second generally horizontal plane parallel to and separate from the first generally horizontal plane. 
     Further, the lift linkage  136  may include a second hydraulic cylinder  146  for pivotally driving (in generally parallel arrangement to the aft port lifting bar  142  and the aft starboard lifting bar  144 ) a fore port tilting bar  148  and a fore starboard tilting bar  150 . The fore port tilting bar  148  and the fore starboard tilting bar  150  are pivotally connected to fore positions of the lateral floating carriage  134 . The second hydraulic cylinder  146  is included with a second user operable hydraulic system for tilting the cradle  168  and adjusting an angle of the cradle  168  relative to the horizontal (e.g., an angle in relation to the first and second planes generally parallel to the generally horizontal plane occupied by the rollable frame  106 . 
     The universal aircraft mule  100  includes hydraulic controls for each of the first and second user operable hydraulic systems. In embodiments, the hydraulic controls (e.g., pump bar  152 ) may be operated from either the port or starboard sides of the universal aircraft mule  100 . The hydraulic controls may be fed with hydraulic fluid from a central hydraulic reservoir  154  positioned behind the first wheel  110  and the second wheel  112 . The central hydraulic reservoir  154  may include a fluid level indicator  156 . 
     Further, the universal aircraft mule  100  may include a hydraulic tilt lock for lockably controlling the amount of tilt for the cradle  168  in a given position. The hydraulic tilt lock may be operable under load at any tilt and height that may be accomplished by the lift linkage  136 . The universal aircraft mule  100  may also include a torsional load stabilizer  158 . In embodiments, the universal aircraft mule  100  is counter-balanced by the arrangement of the cradle  168  in relation to the rollable frame  106 . Additionally, the arrangement of the lateral floating carriage  134  allows the cradle  168  to be skewed (e.g., rotated from a direction parallel to a longitudinal axis of the frame) in a generally horizontal plane. 
     The lateral floating carriage  134  may include one or more anti-rotation stabilizers  160  for preventing substantial rotation of a load carried by the universal aircraft mule  100  (e.g., the aircraft tank  104 ). The first hydraulic system may include a height descent rate control (e.g., a tank metering valve  162 ) for adjustably controlling the rate at which the height of the cradle  168  is allowed to move in a vertical descent. 
     In a presently preferred embodiment, the universal aircraft mule  100  may be utilized to transport any auxiliary, herein and by example, the mule  100  is shown configured to transport a center tank, a wing tank, and/or an A-10 aircraft tank. Further, the universal aircraft mule  100  may include one or more optical (e.g., markings/indicia), mechanical (e.g., latches, tabs, and/or flanges), or electrical (e.g., switches/contacts) positional guidance mechanisms  270  for facilitating (e.g., guiding) loading and unloading of payloads on the universal aircraft mule  100  (e.g., from an aircraft, a storage facility, or the like). 
     The universal aircraft mule  100  may be designed to stack with other universal aircraft mule  100  units along a vertical axis such that the longitudinal axes of the units are generally parallel, and the units are stackable on a shipping pallet  164 . Additionally, the universal aircraft mule  100  may include a transport height locking device  166 , or preventing the units from expanding during shipping and/or transport of the units. 
     It will be appreciated from a review of  FIGS. 7 ,  16 , and  18  that the universal aircraft mule can carry an auxiliary at a height very low to the ground. As will be noted from  FIG. 7 , in a preferred embodiment, the bottom of the auxiliary may be carried at a height approximately equal to the wheel axle height. 
       FIG. 28  schematically illustrates both the lifting and tilting hydraulic systems. The tilting system  200  includes a bidirectional (double acting) hydraulic cylinder operably pressurized via a reservoir  154  filled with hydraulic fluid. An operator may extend or retract the hydraulic cylinder  202  utilizing either hand pump  212  or  214 . Dual counterbalance valve assemblies ( 204 ,  206 ) are preferably utilized to prevent over-running or load runaway. So that accurate pressures may be ascertained on each side of the cylinder  202 , pair of gauge isolators ( 208 ,  210 ) is preferably employed. The tilting system may be operated from either side of the mule  100 . The lift system  300  includes a hydraulic cylinder  302  connected to a velocity fuse  304 . The lifting system also preferably includes a pair of pressure compensated flow controllers ( 306 ,  308 ). Like the tilting system, the lifting system may be operated from either side of the mule  100  via a pair of hand pumps ( 314 ,  316 ). 
     As best illustrated in  FIGS. 23-26 , the mule  100  may be operably employed with a mechanized storage assembly  102  and a mule guide  170 . The mule guide  170  may be a simple mechanical guide system with stop for allowing an operator to readily position the mule  100  in position to receive or unload an auxiliary from/to the mule/storage ( 100 ,  102 ). Likewise, an optical or electromechanical system may also be employed. 
     In a presently preferred embodiment of the mule of the present invention the cradle  168  may be lowered to within 1.0 inches of the ground. To facilitate the low operating envelope a U-shaped frame is utilized so the cradle  168  is not encumbered in lowest position by frame structure. Additionally, the center of gravity is kept outside of the frame in a low-loaded condition such that the cradle  168  center of gravity is centered within the frame when the cradle is in a high-loaded position. 
     The mule  100  of the present invention preferably includes lift, tilt, and rotational adjustments (skew). Prior art mules require brute personnel force to shove and/or push an auxiliary into alignment. The mule  100  of the present invention allows an operator to mechanically adjust lift and tilt to the required install/uninstall height/tilt and then rotate or skew the cradle  168  into a fine adjustment. Thus, even side-to-side (rotational skew and pivot) requires less than 50 pounds of force (the lateral floating carriage bearings  194  and bearing guides  196 ) and may be accomplished without moving the rollable frame  106  of the mule  100 . 
     The mule  100 , in a presently preferred embodiment, includes toe operated, regulated-speed, and descent controllers  192  on both sides of the frame. Hydraulic lift pumps are preferably included on both sides of the frame and it is preferred to utilize a higher speed hydraulic lift pump on one side and a lower speed pump on the other side for finer lift adjustments. It is presently preferred to utilize a single reservoir  154  so that both pumps may be operated simultaneously (for highest speed lift). 
     The mule  100  pump handles are preferably calibrated (and levered) so as to require approximately 50 pounds of force for both lift and tilt. A tilt pressure relief valve  198 , is also preferably included, so the tilt pump handles  252 ,  254  may be lowered or placed at an optimum (location/position) (install/uninstall), for example, lowered stowed location without moving (lifting/tilting) the load. A tilt indicator  172  may also be provided so as to allow personnel to readily pre-adjust a load to the tilt and/or lift height necessary to place the mule  100  into an optimal load/unload position ( FIG. 21 ). All hydraulics are placed and routed in protected areas within the frame. The cradle  168  is easily interchangeable with an alternate cradle for facilitating carriage of any auxiliary having specialized pick-up points. 
     The mule  100  may further comprise cradle spacer  174 , stabilizer slots  176 , tilt hydraulic reservoir  180 , counter balance  182 , strap retention pin  184 , cradle spacer lock  186 , load recess  188 , and tilt direction control  190 . Additionally, mule  100  may be configured to be capable of safely lifting, tilting, pivoting, and transporting a load having a weight of 4500 pounds and having a length of 28 feet. Embodiments of mule  100  may include a hydraulic tilt lock for lockably controlling the amount of cradle tilt in a set position and the hydraulic tilt lock is functional under load and at any cradle tilt and height. Additional embodiments of mule  100  may include a torsional load stabilizer and a frame that is hydraulic counter-balanced, the counterbalancing may include an arrangement of said cradle in relation to the rollable frame. Further embodiments of mule  100  may include a height descent rate control for adjustably controlling a rate at which a height of the cradle is allowed to move in a vertical descent. Further, embodiments of mule  100  may include a hydraulic tilt lock for lockably controlling an amount of cradle tilt in a set position. The hydraulic tilt lock may be functional under a load and at any cradle tilt and height.