CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Provisional Patent Application No. 61/335,966 filed on Jan. 15, 2010. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    This invention relates to fork lifts, hand trucks and other apparatus for lifting a load and transporting it. 
       BACKGROUND OF THE INVENTION 
       [0003]    A prior art load transport system is shown in  FIG. 1 . The prior art system includes product trailer  101  pulled by tractor  102 . Attached to the front of tractor  102  is hand truck  103 . Set of roll-up doors  104  are provided on the product trailer to access product stored on shelves inside. Hand truck  103  is sometimes mounted onto the back of the product trailer. 
         [0004]    In a typical prior art approach, the product trailer is loaded at the distribution center with pallets of product. The driver follows a predetermined route based on the order in which the pallets were loaded. On arrival at one of the retail stores, the driver removes the hand truck from its mount. The driver opens the roll up door to access the correct pallet. The driver manually loads the product onto the hand truck. Depending on the load, the driver may have to climb in the bay to reach the correct product. The driver then manipulates the hand truck underneath the stacks of boxes and cartons on the ground before moving them into the retail store. Once the driver has a sufficient amount of product on the hand truck he moves it to a staging area in the retail store. The driver continues to load and move the product into the retail store until the order is complete. The driver restocks the shelves and then moves any remaining delivered product to a storage location in the retail store. The driver removes the hand truck and secures it to the truck. When boxes are stacked beyond a certain point a step stool or built-in steps in the truck will allow the driver to reach the more highly placed boxes. Thus, utilizing the prior approach, the driver will physically handle each component of product (e.g. case) four times before stocking is complete. 
         [0005]    To compensate for fatigue, the driver/loader will often begin the day by unloading boxes and cartons from near the top of the product trailer and end the day by unloading boxes and cartons near the floor. The unloading process thus requires that the distribution center stack each pallet, by retail location need, from bottom to top as required by the product transport run for the day. 
         [0006]    There are a number of problems with the typical prior art approach. A first problem is that the driver or loader places excessive strain on his back, and on leg and arm muscles when reaching up and out to retrieve heavy boxes and cartons from within the product trailer. Considerable strain is also experienced when placing the heavy boxes and cartons on the ground and when loading or unloading inside the retail store. Hence, the prior art approach is injury prone. Considerable liability insurance is required to protect drivers as a result. 
         [0007]    A second problem is that the driver must manually manipulate the cartons and boxes into the retail store using the hand truck. Many times there are significant inclines to be traversed in moving the hand truck from outside to inside the retail store environment. The hand truck and product must be moved through constricted door and walk ways. Many times the walkways are severely inclined or include steps. 
         [0008]    A third problem is that the product trailer must be unloaded from top to bottom, in order, so that any changes to the nm for the day will result in additional manual manipulation of materials, costing time and effort. Additional manipulation of product generally increases product damage and loss. It is preferable to provide the driver a means by which to access and more easily remove different product at different times from the trailer. 
         [0009]    It is then desirable to reduce injury, potential liability and product loss in unloading and moving product from a product truck to a storage location. Therefore, a mechanism is needed to manipulate heavy boxes and cartons of product trailers. 
         [0010]    The prior art has thus far not successfully met the need. For example, U.S. Pat. No. 6,921,095B2 to Middleby discloses a hand trolley that includes a chassis formed from side frames comprising parallel frame members, wheels and a base platform provided with a load lifting carriage having a lifting surface. The carriage can be raised from a low position on the base platform to an elevated position by operating a hand winch. However, the repeated use of a hand winch does not eliminate the risk of injury. 
         [0011]    As another example, U.S. Pat. No. 6,530,740B2 to Kim et al. disclose a hand truck with an electrically operated lifting platform. The hand truck includes a frame on both sides of which two guide rails are formed. The frame is provided with a threaded shaft vertically supported on the frame to be vertically moved, one or more stabilizing bars forwardly extended from the frame, and two wheels rotatably attached to the rear portion of the frame. However, Kim et al. do not disclose a method of manipulating the frame through constricted doorways or inclined walkways. 
         [0012]    U.S. Publication No. 2008/0224433A1 to Setzer et al. disclose a hand truck comprising a powered lifting/lowering tray and controller. The control unit is configured for causing a tray to rise and lower as desired. A scale is mechanically associated with the tray for measuring the weight of an item placed on the scale. However, no provision is made for carrying the hand truck by a vehicle or reconfiguring the hand truck during operation. 
         [0013]    U.S. Pat. No. 6,601,825 to Bressner discloses a lifting device. The lifting device enables adaptation for objects of varying size. The lifting device includes a mast separable into a plurality of sections and a pulley supported by a first section of the mast. However, Bressner discusses no way to ease the burden of lifting and stacking product. 
         [0014]    U.S. Pat. No. 5,575,605 to Fisher discloses a collapsible, wheeled shopping cart having a horizontal shelf which is vertically movable for loading. The movable shelf may be automatic and movable upwardly when the load on the shelf is decreased or is selectively movable upwardly by a hand crank of a threaded jack or by a piston and cylinder assembly powered by a source of compressed fluid, but Fisher does not eliminate or reduce the possibility of injury due to loading or unloading. 
         [0015]    EP Application No. 0726224 to Berg discloses a drum lifting and transporting device. The device has a wheeled frame which stands in an upright position and has vertically moveable drum clamp. A pair of front legs extend generally forwardly and outwardly from the frame. However, Berg also fails to provide a solution for negotiating constricted doorways, walkways or inclines. 
         [0016]    The prior art fails to disclose or suggest a mobile load transporter useful for loading and unloading product trucks and similar delivery trucks while being adaptable to various walkways and doorways and while also providing ease of attachment to a vehicle for transport. 
       SUMMARY OF INVENTION 
       [0017]    The present embodiments describe is a load transporter suitable to transport product cases from a product delivery truck into a retail store. Other embodiments are conceived for loading, unloading and transporting many types of loads in the context of delivery trucks and fork lifts suitable for warehouses, factories, and narrow areas such as corridors, elevators, walk-in coolers and retail doorways. 
         [0018]    The preferred embodiment load transporter comprises a frame assembly, a mast assembly, a fork assembly and a sheet metal assembly. 
         [0019]    The frame assembly comprises a frame to which front arms are movably attached via a pair of actuators. The actuators allow for lateral expansion of the front arms. A left wheel motor with left rear wheel attached is fastened to the left side of the frame assembly. A right wheel motor with right rear wheel attached is fastened to the right side of the frame assembly. Front left and front right wheel assemblies are attached to the left and right arms, respectively, for support of the load and forward stabilization during transport. 
         [0020]    The mast assembly is rotatably attached to the frame assembly at a pivot point near the lower front of the frame assembly. The mast assembly is further attached to the frame assembly by left and right mast actuators rotatably fastened near the top of the frame assembly and rotatably fastened to the mast assembly. The mast assembly can be tilted from about three (3) degrees behind vertical to about ten (10) degrees forward of vertical via the left and right mast actuators, to aid in adjusting the center of gravity of the machine during transport of a load. 
         [0021]    The mast assembly comprises a telescoping frame movably attached to a lower mast frame. The telescoping frame includes a pair of telescoping channels. The lower mast frame includes a pair of mast channels. The pair of telescoping channels is constrained to move vertically within the pair of mast channels by a set of mast roller bearings traveling within the set of telescoping channels. 
         [0022]    The fork assembly comprises a fork frame to which a left and a right fork are rotatably attached. The fork assembly includes a pair of stops to limit the rotation of the left and right forks. The fork assembly is movably attached to the pair of telescoping channels. The fork assembly is constrained by a pair of upper stops attached to the pair of mast channels and a pair of lower stops attached to the pair of telescoping channels. The fork assembly further includes a hydraulic fork lift actuator, fastened at one end to the lower mast frame and fastened at the other end to a fork chain pulley assembly. The fork chain pulley assembly also includes a pair of pulleys. A pair of chains engage the pair of pulleys. The chains are attached to the fork assembly to the lower mast frame. In an alternate embodiment, the left and right forks are attached so as to slide laterally into position onto the fork assembly. 
         [0023]    The sheet metal assembly which is attached to the frame assembly supports working components of the load transporter in addition to offering protection from the elements. 
         [0024]    An electrical control system is electrically connected to the left and right wheel motors. The hydraulic control system is electrically connected to a set of directional control valves driving the left and right mast tilt actuators, the left and right arm actuators and the hydraulic fork lift actuator. The user interface is preferably a set of joystick controls and a display screen serving as a control input and status indicator for the electrical control system and to the hydraulic control system. 
         [0025]    A vehicle mount is provided for attaching the load transporter to a vehicle or trailer. The vehicle mount includes a rear enclosure, a hydraulic lift frame movably attached to the rear enclosure and a lift ramp attached to the hydraulic lift frame. 
         [0026]    A user interface is provided that includes hardwired functions and wireless functions. A wireless remote control system is provided which enhances the ability of the load transporter to perform. For example, the user may manipulate the load transporter into a door opening without the need for a second person to hold the door open for the operator. 
         [0027]    In the preferred embodiment, the load transporter is powered by 12 VDC AGM (absorbed glass matt) batteries or similar type of deep-cycle battery. A load cell consisting of a bank of 12 volt DC batteries mounted within the vehicle mount has the ability to provide a large volume of stored charge back to the 12 VDC AGM batteries within a connected load transporter. The vehicle mount includes an overnight, AC plug-in charging system. 
         [0028]    These and other inventive aspects will be further described in the detailed description below. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0029]    The disclosed inventions will be described with reference to the accompanying drawings. 
           [0030]      FIG. 1  is a perspective view of a prior art product tractor and trailer including a hand truck mounted to the tractor. 
           [0031]      FIGS. 2A ,  2 B,  2 C,  2 D and  2 E provide perspective views of a load transporter. 
           [0032]      FIGS. 3A ,  3 B and  3 C are exploded views of the frame assembly and frame assembly components of a load transporter. 
           [0033]      FIGS. 4A and 4B  are exploded views of the frame assembly, mast assembly, fork assembly and related components of a load transporter. 
           [0034]      FIG. 5  is an exploded view of the sheet metal assembly and various components. 
           [0035]      FIG. 6  is a circuit diagram showing the control circuit for the load transporter. 
           [0036]      FIG. 7  is a hydraulic circuit diagram of the hydraulic system of the load transporter. 
           [0037]      FIGS. 8A ,  8 B and  8 C provide a side view of three positions of the fork assembly as actuated within the mast assembly. 
           [0038]      FIGS. 9A ,  9 B,  9 C,  9 D,  9 E and  9 F provide perspective views of a load transporter carrier assembly attached to a product trailer. 
           [0039]      FIG. 10  is a pictorial diagram of the motor joystick control, hydraulic joystick control and outrigger controls. 
           [0040]      FIG. 11  is a flow chart of a preferred method of operation for the load transporter. 
           [0041]      FIG. 12  is a flow chart of a preferred method of lifting a load. 
           [0042]      FIG. 13  is a block diagram depicting an alternate embodiment of the load transporter control circuit incorporating wireless controls. 
       
    
    
     DETAILED DESCRIPTION 
       [0043]    A preferred embodiment load transporter is now described beginning with the various perspectives shown in  FIGS. 2A ,  2 B,  2 C and  2 D. Load transporter  1  comprises frame assembly  2 , mast assembly  30 , fork assembly  50  and sheet metal assembly  60 . Frame assembly  2  forms the core part of the load transporter to which mast assembly  30  and sheet metal assembly  60  are attached. Fork assembly  50  is movably attached to mast assembly  30 . Mast assembly  30  is rotatably attached to frame assembly  2  so that mast assembly may be rotated from vertical as shown in  FIG. 2E . A rider platform  70  is rotatably attached to the back of load transporter  1  to enable a rider to operate the load transporter without risk of injury to feet and toes during transport. The dimensions of the fork assembly, the mast assembly and the frame assembly are chosen to enable a small footprint for the load transporter, further enabling access to narrow throughways and small areas to pick up and transport loads into areas that traditionally require humans to physically lift and carry loads. 
         [0044]      FIGS. 3A ,  3 B and  3 C show the frame assembly and frame with their components and features. Frame assembly  2  comprises frame  5 , right front arm  6  and left front arm  7 . The frame assembly components are preferably made of steel and attached by welding or by bolts and nuts as required for manufacturing and ease of assembly. 
         [0045]    Frame  5  has right frame plate  5   a  and left frame plate  5   b  attached by cross member  5   c . To the right frame plate is attached right side plate  5   d  and right motor flange  5   g . To the left frame plate is attached left side plate  5   e  and left motor flange  5   h . Right side plate  5   d  is attached to left side plate  5   e  by bottom plate  5   f . The right and left side plates include right and left curved slots  5   i  and  5   j , respectively. Left channel  3  and right channel  4  are attached to the left and right frame plates and to the left and right side plates to complete the frame. Two pivot holes, left pivot hole  35   b  and right pivot hole  35   a  are drilled through frame  5  from the left and right sides, respectively. 
         [0046]    Right front arm  6  slides into right channel  4  and left front arm  7  slides into left channel  3 . Right front wheel assembly  8  is attached to right front arm  6  and left front wheel assembly  9  is attached to left front arm  7 . Left wheel motor  13   a  with left axle  13   b  is attached to left motor flange  5   h  and left rear wheel  14   a  is attached to the left axle. Similarly, right wheel motor  13   c  with right axle  13   d  is attached to right motor flange  5   g . A right rear wheel  14   b  is attached to right axle  13   d.    
         [0047]    Left arm actuator  15   b  is attached to right actuator plate  26   a  by set of hex nuts  28   a . Right actuator plate  26   a  is attached to frame  5  on right side of left channel  3  by set of bolts  27   a . Left arm actuator  15   b  comprises left extender rod  16   b  and left eye  18   b  attached to the left extender rod by left alignment coupler  17   b . Left front arm  7  includes left hole  21   b  for attaching the left actuator and thereby the frame to the left front arm. Left eye  18   b  is attached to left front arm  7  by means of a left actuator pin  20   b  inserted through left hole  21   b  and through left eye  18   b . Slot  22   b  is cut into frame  5  to allow for the left actuator pin and left front arm to slide as far as possible into left channel  3 . 
         [0048]    Right arm actuator  15   a  is attached to left actuator plate  26   b  by set of hex nuts  28   b . Left actuator plate  26   b  is attached to frame  5  on left side of right channel  4  by set of bolts  27   b . Right arm actuator  15   a  comprises right extender rod  16   a  and right eye  18   a  attached to the right extender rod by right alignment coupler  17   a . Right front arm  6  includes right hole  21   a  for attaching the right actuator and thereby the frame to the right front arm. Right eye  18   a  is attached to right front arm  6  by means of a right actuator pin  20   a  inserted through right hole  21   a  and through right eye  18   a . Slot  22   a  is cut into frame  5  to allow for the right actuator pin and right front arm to slide as far as possible into right channel  4 . 
         [0049]      FIGS. 4A and 4B  show the mast and fork assemblies of the preferred embodiment and their attachment to the frame assembly. Mast assembly  30  is rotatably attached to frame  5 . Left hinge pin  34   b  is inserted through left hole  44   b  in the mast assembly, then into left pivot hole  35   b  of the frame assembly, and held in place by a conventional fastener. Similarly, right hinge pin  34   a  is inserted through right hole  44   a  in the mast assembly, then into the right pivot hole  35   a  of the frame assembly and held in place by a conventional fastener. Left mast actuator  31   b  is attached to frame  5  with left rear pin  32   a  and further attached to mast assembly  30  with left front pin  32   b . Right mast actuator  31   a  is attached to frame  5  with right rear pin  32   c  and further attached to mast assembly  30  with right front pin  32   d.    
         [0050]    As shown in  FIG. 4A , fork assembly  50  utilizes a set of roller bearings inserted into channels of the mast assembly so that it may be moved up and down along with the mast assembly. A set of fork roller bearings  58  are rotatably attached to the sides of fork frame  53 . Two roller bearings per side at each of a set of upper and lower positions are preferred. Set of fork roller bearings  58  ride inside the left and right telescoping channels. Fork pin  55  is fixed to fork frame  53 . Left fork  51  and right fork  52  are rotatably fastened onto fork pin  55  via fork eye holes  56   a  and  56   b . Left fork  51  and right fork  52  pivot on fork pin  55  so that the arms of the left and right forks rest on fork stop  57  of the fork frame. 
         [0051]    Referring to  FIG. 4B , mast assembly  30  comprises upper mast frame  45  movably attached to lower mast frame  40 . The linear movement of upper mast frame  45  and the fork assembly is controlled by a fork actuator assembly. 
         [0052]    Lower mast frame  40  comprises right mast channel  41   a , left mast channel  41   b , lower plate  42  connecting the right mast channel to the left mast channel near the lower end and a fork actuator mount  43  connecting the right mast channel to the left mast channel near the upper end of the mast channels. Left hole  44   b  and right hole  44   a  are positioned in lower plate  42 , near the right and left mast channels, respectively. Pair of upper stops  36   a  are attached to the right and left mast channels near the top of the lower mast frame. 
         [0053]    Fork actuator  80  is attached to lower mast frame  40  at lower plate  42  and at fork actuator mount  43  by fork actuator mounting bolts  88 . Fork actuator  80  includes movable fork actuator rod  81  to which chain pulley assembly  82  is attached. Chain pulley assembly  82  comprises actuator stop  87  having pulley rod  86  inserted through to which pair of pulleys  83  are rotatably mounted and held in place by pair of washers  84  and pair of snap connectors  85 . Fork actuator  80  is attached to the lower mast frame so that movable fork actuator rod  81  is inserted through hole  46  in fork actuator mount  43  so that the fork actuator rod may freely move in the vertical direction for a length approximately equal to the length of fork actuator  80 . 
         [0054]    Pair of chains  89  traverse pair of pulleys  83 . One end of each chain is attached to fork actuator mount  43  and the other end of each chain attached to the fork assembly. 
         [0055]    Upper mast frame  45  comprises left telescoping channel  38   b , right telescoping channel  38   a , cross-member  39  connecting the right telescoping channel to the left telescoping channel near the lower end, and top plate  37  connecting the right telescoping channel to the left telescoping channel at the top end. Set of mast roller bearings  29   a - c  are attached to the left and right telescoping channels in pairs. Upper pair  29   a  is positioned near the top of the channels. Pair  29   b  is centrally attached. Pair  29   c  is attached near the bottom. Pair of lower stops  36   b  are attached to the right and left telescoping channels near the bottom of the upper mast frame. 
         [0056]    Upper mast frame  45  is positioned in lower mast frame  40  adjacent to the set of mast roller bearings and mast channels,  41   a  and  41   b , in such a way that the upper mast frame is constrained to translate linearly with respect to the lower mast frame. 
         [0057]    As shown in  FIG. 8A , fork assembly  50  is in position  401  with the forks at or near ground level  400  and well below the top of lower mast frame  40  at position  402 . Fork actuator rod  81  is in a low position. Upper mast frame  45  is in position  403 . Actuator stop  87  is in contact with the top plate of upper mast frame  45 . 
         [0058]    As shown in  FIG. 8B , fork actuator rod  81  is actuated to a medium length which in turn places fork assembly  50  at position  404 , a medium height above ground level  400 . Upper mast frame  45  is also in a medium position  405  with respect to position  402  on the lower mast frame; position  402  is stationary with respect to ground level  400 . 
         [0059]    As shown in  FIG. 8C , fork actuator rod  81  is actuated to full length which in turn places fork assembly  50  at position  406 . Upper mast frame  45  is fully extended to position  407  with respect to position  402  on the lower mast frame; position  402  remains stationary with respect to ground level  400 . 
         [0060]    In  FIGS. 8A-8C , pair of chains  89  are fixed in length and form a 2:1 pulley system, along with chain pulley assembly  82  including actuator stop  87 , whereby when the fork actuator is raised a distance X, the fork assembly is raised a distance  2 X. 
         [0061]    As shown in  FIG. 5 , sheet metal assembly  60  attaches to the right side of frame  5  near the right side plate and the cross member with a set of right sheet metal screws  61   a , and, attaches to the left side of frame  5  near the left side plate with set of left sheet metal screws  61   b . Sheet metal assembly  60  includes a set of doors  62  for accessing the inner components of the load transporter and for storage. Stop button  64 , joystick  63   a , a hydraulic control panel  63   b  and display  63   c  are attached to sheet metal assembly  60 . 
         [0062]    Rider platform  70 , is rotatably attached to frame  5  with pair of threaded pins  72   a  and accompanying nuts  72   b , one threaded pin and one nut on either side of the frame. Rider platform  70  is further attached to frame  5  with a pair of threaded slide pins  73   a  in combination with pair of slide spacers  73   b , pair of slide washers  73   c  and pair of slide nuts  73   d . Rider platform  70  is latched into a closed position with step latch  75  which is attached to frame  5 . Rider platform  70  is released by step latch  75  into a down position. 
         [0063]    Internal components include a motor controller unit, a hydraulic manifold, and a set of batteries. Battery pan  66 , which holds batteries  65 , is attached to frame  5 . The batteries are held in place with battery holder  67 , battery bolt  68   a , pan  66  and nut  68   b . A motor controller unit, a hydraulic manifold, and a hydraulic pump system are also attached to frame  5 . 
         [0064]    Referring to  FIG. 6 , control circuit  200  of the load transporter includes a motor control circuit  201 , power circuit  202  and hydraulic control circuit  203 . Pair of 12V batteries  220  are connected in series to form a 24V power source. First circuit breaker  222  connects the negative terminal of a first battery to the positive terminal of a second battery. Positive supply terminal  225  and negative supply terminal  224  are available for connection to the other components. 
         [0065]    Motor control circuit  201  comprises controller unit  210  suitable to control left drive motor  211  and right drive motor  212 . Motor joystick control  213  incorporating power switch  216  is electrically connected to the controller unit, as are strobe light  214  and audible alarm  215  for indicating that the load transporter is moving in reverse. Display  280  is also connected to the controller unit. Emergency stop button  218  is connected between controller unit  210  and positive supply terminal  225  in such a way that the connection between controller unit  210  and power circuit  202  is broken when the emergency stop button is depressed. 
         [0066]    Controller unit  210  further comprises a microcontroller  206  connected to on-board memory  207  for storing programmed movements of the load transporter. 
         [0067]    Batteries  220  are preferably 12 VDC AGM (absorbed glass matt) batteries of 135 Ah capacity or similar type of deep-cycle battery. Also, AGM type batteries charge approximately five times faster than a traditional lead-acid battery, and have a much lower self-discharge rate than lead-acid batteries allowing for better charge recovery when not in use. 
         [0068]    Hydraulic control circuit  203  comprises hydraulic manifold  230  and hydraulic control panel  232 . 
         [0069]    Hydraulic control panel  232  comprises keyed power switch  236  and power indicator light  233  along with right outrigger control  234 , left outrigger control  235 , and hydraulic joystick control  237  for fork actuation (lift) and mast actuation (tilt). The hydraulic joystick control is electrically connected to the hydraulic manifold to control hydraulic fluid pressure to the fork actuator. The hydraulic joystick control is further electrically connected to the hydraulic manifold to control hydraulic fluid pressure to the left and right mast actuators. The left and right outrigger controls are electrically connected to the hydraulic manifold to control hydraulic fluid pressure to the left and right arm actuators. 
         [0070]    Hydraulic control panel  232  includes power connections to positive supply terminal  225  and negative supply terminal  224 , the positive supply terminal preferably connected by second circuit breaker  226 . Hydraulic control circuit  203  includes pressure switch  238  and ammeter  239  placed in line with the power connections. 
         [0071]    Hydraulic control circuit  203  controls four hydraulic control lines associated with four hydraulic directional control valves. Hydraulic control line  247  is an electrical connection between hydraulic control circuit  203  and directional valve  263 . Hydraulic control line  243  is an electrical connection between hydraulic control circuit  203  and directional valve  273 . Hydraulic control line  244  is an electrical connection between hydraulic control circuit  203  and directional valve  274 . Hydraulic control line  246  is an electrical connection between hydraulic control circuit  203  and directional valve  283 . 
         [0072]    The hydraulic control circuit is further connected to an upper micro-switch  276  placed at the upper limit of travel on the set of upper stops and a lower micro-switch  277  placed on the lower stops at the lower limit of travel with a corresponding hydraulic circuit included to disable further hydraulic flow when either the upper or lower micro-switches are activated. 
         [0073]    Referring to  FIG. 7 , hydraulic system  250  is a closed system containing a hydraulic fluid supplied from hydraulic reservoir  251  and pressurized by hydraulic pump  255 . Hydraulic pump  255  is attached to hydraulic reservoir  251  and to hydraulic supply lines  257 . Pressure switch  238  is also attached to hydraulic supply lines  257  and to hydraulic reservoir  251  via pump bypass line  259  to allow for system pressure regulation. Hydraulic return lines  256  and hydraulic supply lines  257  are further attached to hydraulic manifold  230 . The set of actuators include right mast actuator  261  and left mast actuator  262  for tilting the mast assembly, right arm actuator  271  and left arm actuator  272  for expanding the front right and front left arms as an outrigger for the load transporter, and fork actuator  281  for raising and lowering the fork assembly. 
         [0074]    Hydraulic manifold  230  includes a set of directional valves comprising directional valve  263 , directional valve  273 , directional valve  274 , and directional valve  283 . The set of directional valves are each connected to hydraulic supply line  257  and hydraulic return line  256  and to a first and a second pressurizing chamber of each of the set of actuators. The set of directional valves are electrically connected to and controllable by the hydraulic control circuit to control fluid pressure to the pressurizing chambers of the set of actuators. 
         [0075]    The set of directional valves are preferably 4-port 3-state directional control valves comprising an “a” and a “b” solenoid. A suitable part for each directional valve is the Argo-Hytos part number RPE3-063Y11/02400E1. Where a check valve is used, the check valve is of a pilot-to-open type. A suitable part for the check valve is model CKCB from Sun Hydraulics. A suitable part for the pump and reservoir system is the 3 KW DC HPU from Hydra-Lube of St. Charles, La. Suitable hydraulic actuators are HLLH25250B for the fork actuator, HLLH3200B for the tilt actuator, and HLP0200/0 for the front arm actuators also from Hydra-Lube. 
         [0076]    For reference, directional valve positional states for the hydraulic system are: state “0” which connects both chambers of a hydraulic actuator to the return side of the hydraulic system and is activated by powering neither of the “a” and “b” solenoids; state “a” which connects a first chamber of the hydraulic actuator to the supply side and the second chamber of the hydraulic actuator to the return side thereby pressurizing the first chamber, and is activated by powering the “a” solenoid alone; state “b” which connects the second chamber of the hydraulic actuator to the supply side and the first chamber to the return side thereby pressurizing the second chamber, and is activated by powering the “b” solenoid alone. 
         [0077]    The hydraulic lines of the left and right mast actuators hydraulic lines are connected together and to directional valve  263  by supply line  265 . Check valve  264  is further inserted into supply line  265  to hold pressure against a load experienced by the left and right mast actuators. Return line  266  is connected between the left mast actuator and directional valve  263  and also to the pilot port of check valve  264 . Directional valve  263  is controlled by the hydraulic joystick control. 
         [0078]    The right arm actuator is connected to directional valve  273  by supply line  275  and return line  276 . The left arm actuator is connected to the directional valve  274  by supply line  277  and return line  278 . Directional valves  273  and  274  are controlled by the left and right outrigger controls. 
         [0079]    The fork actuator is connected to directional valve  283  by supply line  285 . Check valve  284  is further inserted into supply line  285  to hold pressure against a load on the fork actuator. Return line  286  is connected between the fork actuator and the directional valve  283  and also to the pilot port of check valve  284 . Directional valve  283  is controlled by the hydraulic joystick control. 
         [0080]    A preferred embodiment of the joystick controls and outrigger controls are described in  FIG. 10  with references made to  FIG. 7 . Motor joystick control  213  is a proportional control capable of sensing placement of a joystick within a circle divided into quadrants by the directions “move forward”, “move backward”, “turn right” and “turn left” and with the motor control circuit is further capable of generating a left motor rotational speed and a right motor rotational speed, in proportion to the sensed placement within the circle to motivate the load transporter. For example, with a joystick placement at position  227 , the motor joystick control is programmed to cause a forward and right turning motion of the load transporter at about half of the maximum speed. 
         [0081]    Hydraulic joystick control  237  is a control capable of sensing placement of a joystick in one of the positions: “center”, “lower load”, “raise load”, “tilt back”, “tilt forward”. Hydraulic joystick control  237  preferably operates as a five position momentary switch with the normal position at “center”. 
         [0082]    Left outrigger control  235  is a momentary control switch with three positions: a normally “central” position, an “out-L” position and an “in-L” position. 
         [0083]    Right outrigger control  234  is a momentary control switch with three positions: a normally “central” position, an “out-R” position and an “in-R” position. 
         [0084]    Referring to  FIG. 11  with further reference to  FIGS. 10 and 7 , control of the load transporter will be described. Actuation of the keyed power switch enables the hydraulic functions of the load transporter. Control process  500  starts at step  501 , wherein keyed power switch is sensed and when the keyed power switch is turned on, power is supplied to the hydraulic control circuits at step  502 . When the keyed power switch is turned off, power is disabled for the hydraulic control circuits at step  503 . 
         [0085]    Note that the motor control functions are separated from the hydraulic control functions of the load transporter. When keyed power is turned off to the hydraulic control circuits, the hydraulic actuators are “locked” into position while the motor control functions remain powered and enabled, providing added safety to the rider and stability of the load during transport. For example, the rider while operating the motor controller accidentally bumps the hydraulic controller. If keyed power is turned off, then no change in the hydraulic actuator states will occur as a result of the bump. If the hydraulic controller is bumped without the keyed power safety feature, the front arms could extend while motivating the load transporter through a narrow passageway or a load could be destabilized and dropped. 
         [0086]    At step  505  the motor joystick position is sensed by the motor control circuit and at steps  506  and  507 , power is applied to the left and right wheel motors in proportion to the joystick position. For example, if the joystick is fully in the “move forward” position, the left and right motor speeds are adjusted to be about equal at +S F  by the motor control circuit; if the joystick is fully in the “move backward” position, the left and right motor speeds are adjusted to be about equal at −S B  by the motor control circuit; if the joystick is fully in the “turn right” position, the right motor speed is adjusted to about +S F  and the left motor speed is adjusted to −S B  by the motor control circuit. To illustrate the proportional control, if the joystick is in position  227 , the right motor speed is adjusted to about +⅔ S F  and the left motor speed is reduced to about +⅓ S F , causing a rightward turn of the load transporter while moving generally forward. 
         [0087]    In one aspect of the preferred embodiment, it is understood that the load transporter may execute a “zero-turn”, that is, caused to rotate in position, clockwise when the joystick is placed fully in the “turn right” or counterclockwise when fully in the “turn left” position, thereby increasing its maneuverability in especially difficult conditions and small storage areas such as ramps, doorways, aisles and walk-in coolers. 
         [0088]    At step  510 , the emergency stop button is sensed. If at any time during operation, the emergency stop button is depressed, power is disengaged from both wheel motors in step  511 . In another preferred embodiment, electric brakes are supplied in each motor assembly, which are engaged upon sensing when the emergency stop button is depressed and when each of the motor joysticks is placed in its central position. 
         [0089]    To stabilize a load from side to side, the left and right front arms are extended using the left and right outrigger controls to send an electrical signal to directional valves  273  and  274 . 
         [0090]    According to step  525  the left outrigger control  235  is sensed by the hydraulic control circuit. When left outrigger control  235  is in the “center” position, directional valve  274  is in the “0” state according to the hydraulic control circuit wherein the left front arm remains in its current position. At step  526 , when left outrigger control  235  is in the “out-L” position, directional valve  274  is placed in the “a” state by the hydraulic control circuit wherein the left arm actuator is pressurized to move it outward. At step  527 , when left outrigger control  235  is in the “in-L” position, directional valve  274  is placed in the “b” state by the hydraulic control circuit wherein the left arm actuator is pressurized to move it inward. 
         [0091]    According to step  535  the right outrigger control  234  is sensed by the hydraulic control circuit. When right outrigger control  234  is in the “center” position, directional valve  273  is in the “0” state according to the hydraulic control circuit wherein the right front arm remains in its current position. At step  536 , when right outrigger control  234  is in the “out-R” position, directional valve  273  is placed in the “a” state by the hydraulic control circuit wherein the right arm actuator is pressurized to move it outward. At step  537 , when right outrigger control  234  is in the “in-R” position, directional valve  273  is placed in the “b” state by the hydraulic control circuit wherein the right arm actuator is pressurized to move it inward. 
         [0092]    In step  515 , the hydraulic joystick position is sensed by the hydraulic control circuit. When the hydraulic joystick is in the “center” position, directional valves  263  and  283  are in state “0” according to the hydraulic control circuit wherein the tilt does not change and the fork position does not change. At step  518 , when hydraulic joystick control  237  is in the “raise load” position, directional valve  283  is placed in the “a” state by the hydraulic control circuit wherein the fork actuator is pressurized and moves upward. At step  519 , when hydraulic joystick control  237  is in the “lower load” position, directional valve  283  is placed in the “b” state by the hydraulic control circuit wherein the fork actuator is de-pressurized and moves downward. At step  516 , when hydraulic joystick control  237  is in the “tilt forward” position, directional valve  263  is placed in the “a” state by the hydraulic control circuit wherein the mast actuators are pressurized so as to move the top of the mast forward. At step  517 , when hydraulic joystick control  237  is in the “tilt backward” position, directional valve  263  is placed in the “b” state by the hydraulic control circuit wherein the mast actuators are pressurized so as to rotate the top of the mast backward. Stabilizing the load by tilting the mast allows the operator to adjust for walkway inclines and to adjust for stairs. 
         [0093]    Control process  500  repeats steps  501 ,  505 ,  510 ,  515 ,  525  and  535  to control the load transporter. 
         [0094]    In another embodiment, the motor control functions relating to steps  506  and  507  can be programmed and recalled for a variety of automated functions using the microcontroller and memory of the motor controller unit. 
         [0095]    In an alternate embodiment, an automatic stabilizing mode may be enabled by including a horizontal sensing unit in the hydraulic control panel to sense a tilt angle of the mast required to bring the center of gravity of a load into stability. The controls circuit automatically controls the mast tilt based on the sensed tilt angle by sending signals to the directional valve  263 . 
         [0096]    The left and right outrigger controls are preferably extended to stabilize a load when it is at a high position on the mast. When the load is positioned lower and closer or between the front arms, the center of gravity is correspondingly lowered; the left and right front arms are contracted to narrow the effective width of the transporter to transport the load through narrow doorways and aisles. To stabilize the load from front to back while moving the load transporter up or down an incline, the tilt of the mast assembly is changed using the hydraulic joystick control. 
         [0097]    A preferred method of operation to lift a load is presented in the flowchart of  FIG. 12 . Beginning with step  602 , the left and right front arms are moved to an extended position via the left and right outrigger controls to actuate the left and right arm actuators. In step  604 , the fork assembly is lowered, via the hydraulic joystick control, to a position where the fork tines are at or near the ground level, below and between the left and right arms. At step  606  the load transporter is moved forward using the motor joystick control, to engage the fork tines with a load at a first position situated at or near the ground surface. At step  608 , the load transporter supports the load by raising the fork assembly to lift the load, using the hydraulic joystick control to control the fork actuator. At step  610 , the fork assembly is further raised whereby the load is positioned above the left and right arms. At step  612 , the left and right front arms are moved to a contracted position via the left and right outrigger controls controlling the left and right arm actuators. At step  614 , the left and right wheels are activated to move the load transporter and thereby transport the load from the first position to a second position. Adjusting the width of the transporter by extending and retracting the front arms allows the operator to navigate confined spaces such as doorways and aisles, while maximizing load stability during loading and unloading. 
         [0098]    In an alternate embodiment, the load (e.g. pallet) is lowered after step  612  to rest on the contracted front arms, where the load is then securely transported from one location to another as in the remaining steps. 
         [0099]      FIGS. 9A ,  9 B,  9 C,  9 D,  9 E and  9 F show various views of a preferred embodiment vehicle mount for carrying the load transporter. Vehicle mount includes a lift frame  310  movably attached to vehicle mount  312  to which enclosure  301  is further attached. Vehicle mount  312  is affixed onto an existing vehicle  300  to house load transporter  302 . Two hand truck mounts  303  are affixed on either side of the rear enclosure and serve to support the rear enclosure. The rear enclosure includes a cover for protecting the load transporter from damage due to exposure to the elements and traffic hazards. 
         [0100]      FIG. 9F  shows the detail of the vehicle mount. Lift frame  310  comprises a pair of vertical members attached to a lower platform  313 , a frame crossmember  335  and a set of battery shelves connecting pair of vertical members  311 . Lift frame  310  further comprises a pair of stabilizing braces  314  connecting pair of vertical members  311  to lower platform  313 . A pair of guides  315  are attached to the pair of stabilizing braces  314 . A lift ramp  305  is rotatably attached to lift frame  310 . 
         [0101]    Vehicle mount  312  comprises an upper crossmember  323  and a lower crossmember  324  welded to a pair of vertical members  325 . A lift plate  322  is attached to the upper crossmember  323 . Lift frame  310  is attached to vehicle mount  312  with a pair of slides  317  attached to the pair of vertical members  325 , the pair of slides supporting translation of the lift frame with respect to the vehicle mount. A cable  321  is connected between lift plate  322  and a winch  320  which is affixed to lift frame  310 . Winch  320  is powered by a set of batteries  318  connected through a control  330 . Cable  321  is preferably a ⅜ inch wire rope. A charging regulator  340  is connected to set of batteries  318  for charging the load transporter while in the vehicle mount. Set of batteries  318  are further connected to the vehicle charging system to allow for charging while the vehicle is operating. Control  330  and charging regulator  340  are suitably mounted on enclosure  301 . 
         [0102]    A set of mechanical latches secures the lift frame and the lift ramp  305  in a locked position suitable for travel. A mechanical latch for the frame is positioned to be manually operated to latch the lift frame into an up position. The mechanical latch is manually released to allow for unloading. A mechanical latch for the lift ramp is preferably a set of wing bolts  342  inserted through holes  341  of the lift ramp after the lift ramp is rotated. 
         [0103]    In operation, lift frame  310  and lift ramp  305  are lowered to ground level using control  330  and winch  320 . Load transporter  302  is driven by an operator over lift ramp  305  and onto lift frame  310 . The operator dismounts load transporter  302 , then lifts and latches the rear step of the load transporter as in  FIGS. 9A ,  9 C and  9 E. The operator then causes the lift frame to move up and off of the ground into a travel position using control  330  and winch as indicated in  FIG. 9D . Additional hand trucks, if used, are removed from and replaced to hand truck mounts  303 . Pair of guides  315  aid in positioning the load transporter. 
         [0104]    After the load transporter is securely aboard the vehicle mount, and the mechanical latches are latched, the load transporter is electrically connected to charging regulator  340  which provides a high amperage rapid refresh charge to the on-board batteries of the load transporter. Furthermore, the charging regulator  340  includes an AC mains connection and charging circuitry to allow overnight charging of both the load transporter batteries and the vehicle mount batteries. 
         [0105]    In  FIG. 13 , an alternate embodiment control system for the load transporter. Motor control circuit  201  and hydraulic control circuit  203  are connected to a wireless receiver unit  205  which is powered by power circuit  202 . Wireless receiver unit  205  is programmed to receive a set of wireless commands embedded in wireless signals generated by wireless transmitter unit  204 . Wireless transmitter unit  204 , includes a power source such as a DC battery, at least one joystick control and a plurality of switches to allow operator  207  to mimic the behavior of the first and second joysticks as well as the outrigger controls and power on/off functions. Wireless transmitter unit  204  is programmed to generate the set of wireless commands based on operator  207  behavior. Motor control circuit  201  and hydraulic control circuit  203  may be operated from the on-board controls or via the wireless receiver. Upon reception of a wireless command, the wireless receiver is further configured to interpret the wireless command, adjust the state of the motor system or hydraulic system according, and provide an electrical signal representing any change of state to the motor control circuit or the hydraulic control circuit as appropriate. 
         [0106]    In a related embodiment, second wireless receiver  209  is electrically connected to hydraulic lift controls  208  for the hydraulic lift frame. In operation, the operator may thus control the load transporter and the vehicle mount without the necessity of climbing aboard the load transporter or the vehicle. 
         [0107]    The specifications and description described herein are not intended to limit the invention, but to simply show a preferred embodiment in which the invention may be realized. Other embodiments may be conceived, for example, having differing dimensional characteristics, having different pivot locations for the mast assembly, having a different mechanism for telescoping the front arms or mast assembly, or having a different means of motorizing the load transporter.
A motorized means of transporting loads includes a fork lift mechanism that features a set of anchored chains fitted to a set of lifting forks for lifting and lowering a load. With a combination electrical/hydraulic system, the lifting and lowering functions can be efficiently obtained. Two load supporting outriggers are provided which can be extended or retracted while transporting a load to aid in navigating constricted spaces. A tilting mast and fork assembly allows for a manipulation of the center of gravity while transporting loads. A joystick function controls the forward, turning, reverse, lifting, and extending and retracting the outriggers. A battery enabled transport provides for flash charging of the onboard batteries to extend useful life.