Abstract:
A self-contained lift truck capable of loading a cargo container by engaging an end of the container, lifting the end of the container, moving the truck toward the container until it contacts the container, then pulling the container forward until it is level on the truck. During loading, the container never slides along the ground, avoiding damage to the ground.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to an apparatus for loading a cargo container onto a vehicle or trailer, and more particularly to a self-contained cargo loading and transport vehicle.  
       BACKGROUND OF THE INVENTION  
       [0002]     Cargo items have long been transported as containerized freight inside rectangular closed boxes, measuring roughly 8 feet wide, 8 feet high, and 20 to 50 feet long. Fully loaded, these containers are often very heavy, approaching 20 tons. Recently, users have begun to use these containers primarily for storage of residential and commercial materials rather than merely for shipment. For example, a container may be delivered by a storage company to a residence, where the users may load the material into the container at their convenience. Later, the storage company accepts the container and delivers it to a long-term storage facility. Because these types of users are not associated with the freight industry, their facilities often have landscaping, driveways, sidewalks, and other loading zones that are not capable of withstanding abuse. A traditional loading and transport vehicle, often called a hook truck, will attach a lift mechanism to the container and lift one end of the container, pull the container up and forward, dragging the other end of the container along the ground, driveway, or roadway, until the container is fully loaded onto the hook truck. Loading the container in this way damages the supporting surface when that surface is not specially prepared for handling freight.  
         [0003]     Alternatively, it is common to use a forklift or similar independent lift device to load a container onto a vehicle. A difficulty encountered by using a forklift is that a forklift requires a great deal of room to maneuver beside the container and vehicle during loading and unloading.  
         [0004]     A third way of loading a container onto the truck uses a jack arrangement to lift the four corners of the container, so that the truck can be driven underneath it; or alternatively, the jacks have wheels so that the container can be rolled onto the truck. A difficulty encountered using this method is that it requires manual labor and considerable assembly and disassembly time to set up the jacks.  
         [0005]     Containers are often loaded onto trailers for transport with a semi-articulated tractor-trailer combination. Typically, containers are loaded onto the trailer from the side using a forklift, or from above using an overhead crane to lift the container from its storage location, swing the container directly over the trailer and then set the container onto the trailer. A forklift takes a considerable amount of maneuvering space. An overhead crane requires expensive capital investment. Either a crane or a forklift takes a large space to operate. In addition, both methods require a place to store the forklift or crane when not in use, as neither can be used to transport the container any appreciable distance. A separate forklift or crane must be provided to unload the vehicle once it arrives at its destination.  
         [0006]     Thus, the invention provides a way to load a container onto a transport vehicle without damaging the surface on which the container rests and while using a minimal amount of space and a minimum of capital investment. The invention also provides for a container transport vehicle with an integral loading mechanism so that it may be used to load the container at the departure point and unload it at the destination.  
         [0007]     Additional advantages and novel features of the invention will be set forth in part in the following description and will become apparent to those skilled in the art upon examination of the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.  
       SUMMARY OF THE INVENTION  
       [0008]     An embodiment of the present invention is made up of an engagement assembly designed to grip a container using engagement points provided on the container, a lift assembly capable of lifting at least one end of the container, a carriage that moves underneath the container during loading, and a control system which controls the interaction of the above components. In operation, a human operator uses the control system to move the engagement assembly next to the container, grip it securely, and then raise one end of the container using the lift assembly. The other end of the container remains on the ground. The carriage moves underneath the container until it contacts the bottom of the container. The lift assembly then pulls the container onto the carriage. The carriage has a set of rollers at the point of contact with the container so that the container can easily roll forward onto the carriage. The lift assembly then continues to move the container onto the carriage until it is in its final position for transport. In the final position, the container is supported at the rear end by a bed of rollers and at the front end by the engagement assembly and the lift assembly. During this operation, no point of the container slides along the ground or support surface.  
         [0009]     Unloading the container from the transport is the reverse of the loading process. The operator uses the control to cause the lift mechanism to push the container towards the rear of the carriage. As the container rolls off the carriage, it tilts until the rear end of the container contacts the ground. The lift assembly then raises the front end of the container from the carriage and the carriage moves from underneath the container. The lift assembly continues to move the container in synchronization with the motion of the carriage so that the rear end of the container remains still. After the container is clear of the carriage, the lift assembly lowers the front end of the container to the ground, and then the engagement assembly disengages from the container.  
         [0010]     An embodiment of the present invention may be used to load a container onto a trailer. First, the container is loaded onto the carriage as described above. Then, the carriage is positioned adjacent to the front of the trailer so that the container can be slid towards the rear, onto the length of the trailer. The lift assembly pushes the container backwards off of the carriage onto the trailer until the container is completely supported by the trailer, the engagement assembly releases the front of the container, and the entire mechanism is moved away from the trailer. Loading a container onto the mechanism is the reverse of the process just described.  
         [0011]     Using embodiments of the invention, the container can be loaded from the ground onto the mechanism and then loaded onto the trailer in a minimum of space. No jacks or external loading equipment is required.  
         [0012]     The purpose of the foregoing summary is to enable the United States Patent and Trademark Office and the public generally, and especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection, the nature and essence of the technical disclosure of the application. The summary is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a block diagram of an embodiment of the present invention.  
         [0014]      FIG. 2  shows an embodiment of the engagement assembly.  
         [0015]      FIG. 3  is a rear view of an embodiment of the lift assembly.  
         [0016]      FIG. 4  is a side view showing an embodiment of the lift assembly, an embodiment of the engagement assembly, and an embodiment of the carriage.  
         [0017]      FIG. 5  is a perspective view of a portion of an embodiment of the carriage, including rollers and a guide.  
         [0018]      FIG. 6  is a schematic representation of an embodiment of the control system.  
         [0019]      FIGS. 7, 8 , and  9  show an embodiment of the present invention at different stages during loading of a container.  
         [0020]      FIG. 10  shows an embodiment of the present invention at the final stage of loading of a container and also shows an embodiment having a trailer hitch.  
         [0021]      FIG. 11  shows the steps in a method of loading a container according to an embodiment of the present invention.  
         [0022]      FIG. 12  shows a control system implemented as a computer, according to an embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     While the invention is susceptible of various modifications and alternative constructions, certain embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed; rather, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims. For example, while embodiments of the present invention were developed in the form of a truck, the invention is not limited to use on a truck and may be used with other vehicles, such as railroad cars. While the invention is not limited to use as a truck, it is expected that various embodiments of the invention will be particularly useful in such devices. Accordingly, the drawings and description of the preferred embodiment are to be regarded as illustrative in nature, and not as restrictive in nature.  
         [0024]     Referring now to  FIG. 1 , an embodiment of the present invention, a lift mechanism  8 , includes four systems working in concert. The first system is an engagement assembly  10  capable of securely gripping a container  200 . The second system is a lift assembly  12  capable of lifting container  200 . The third system is a moveable carriage  14 . The fourth system is a control system  16  that controls the other 3 systems. For reference purposes, “rear,” “rearward,” and “aft” refer to direction extending to the right on  FIG. 1 ; “front,” “foreword,” and “fore” refer to direction extending to the left on  FIG. 1 . “Right” and “right side” refer to the direction to the right when facing forward. Similarly, “left” and “left side” refer to the direction to the left when facing forward.  
         [0025]     An embodiment of the engagement assembly is shown in  FIG. 2 . Engagement assembly  10  includes a roughly triangular, rigid bridle  20  and a pin support structure  22  attached to bridle  20  at a vertex. The connection of support structure  22  is strengthened by a gusset  24  (see also  FIG. 4 ). A fixed pin  26  is rigidly attached to the support structure  22 . A pin  28  is moveably attached to support structure  22  and moved by an actuator  30 . A second support structure  22 , gusset  24 , fixed pin  26 , moveable pin  28 , and actuator  30  are attached to another vertex of bridle  20  so that the two moveable pins  28  oppose each other.  
         [0026]     In a preferred embodiment, bridle assembly  20 , carriages  22 , gussets  24 , and fixed pins  26  are made of steel and welded together. Pins  28  may also be made of steel. Actuators  30  may be pneumatic actuators; alternatively, hydraulic, electric, or other actuators may be used.  
         [0027]     Bridle  20  does not have to be perfectly triangular. As shown in  FIG. 2 , the arms of the triangle may be bent so that the support structure  22  can be welded flush with the sides of bridle  20 , and so that moveable pins  28  are generally orthogonal to support structure  22 . Alternatively, bridle  20  may be any shape that allows pins  26  and  28  to be securely supported and properly located, including any polyhedron or other geometric arrangement.  
         [0028]     The precise location of pins  24  and  26  depend on the corresponding engagement holes in container  200 . Since many of the dimensions of many containers are standard, support structure  22  may be welded in place. However, in another embodiment, support structure  22  may be bolted in place to allow engagement assembly  10  to be adjusted to engage other sizes of containers or storage devices. Pins  26  and  28  may be replaced by clips, hooks, holes, or any other engagement feature required by the design of container  200 .  
         [0029]     Referring again to  FIG. 2 , engagement assembly  10  is suspended from lift assembly  12  by a Heim joint  32 , also called a rod end bearing. Heim joint  32  allows bridle  20  to rotate in the horizontal and vertical planes, so that the engagement assembly  10  can mate flush with container  200  even when lift assembly  12  is not aligned container  200 . Alternatively, Heim joint  32  may be replaced by a ball joint or a combination of hinges and bearings.  
         [0030]      FIG. 3  shows the rear view of an embodiment of lift assembly  12 . As shown in  FIG. 3 , an arm  34  is attached via one or more bearings  35  to a lift arm  36 , so that arm  34  rotates in the fore-aft plane. An actuator  38  (see also  FIG. 4 ) connects to lift arm  36  through structure  40 . A second actuator  42  extends from lift arm  36  to arm  34  to move arm  34  relative to lift arm  36 . Fork  44  is attached to the end of arm  34  to connect with Heim joint  32  on engagement assembly  10 .  
         [0031]     Arms  34  and  36  may be constructed of steel or other sufficiently rigid material. In one embodiment, lift arm  36  is made of a single beam. In another embodiment, lift arm  36  is made of two spaced-apart beams, providing more lateral strength than a single beam. Actuators  40  and  42  are preferably hydraulic actuators; alternatively, other types of actuators may be used.  
         [0032]     Refer now to  FIG. 4 , a side view of engagement assembly  10 , lift assembly  12 , and carriage  14 . Lift assembly  12  is attached to carriage  14 . Lift arm  36 , or lift assembly  12 , is attached to rigid frame  50 , of carriage  14 , via bearings  52 , allowing lift arm  36  to rotate in the fore-aft plane. Cylinder  38  extends from frame  50  to lift arm  36  to move lift arm  36  relative to frame  50 .  
         [0033]     One or more hoses  54  provide working fluid to actuator  30 . Hoses  54  are attached to the lengths of arm  34  and lift arm  36  in a manner to protect hoses  54  during operation. A portion of the hoses  54  are free of arm  34  and lift arm  36  and pass around joint  32  so that engagement assembly  10  may swing freely without damaging hoses  54  or binding engagement assembly  10 . Additional hoses, not shown, conduct working fluid to actuators  38  and  42 , and are mounted to arm  34  and lift arm  36  in a similar fashion.  
         [0034]     Carriage  14  may include one or more rollers  56 . In one embodiment, rollers  56  are attached to frame  50 . In another embodiment, a plurality of rollers  56  is mounted to a sub-frame  58 , as shown in  FIGS. 4 and 5 . Sub-frame  58  is mounted to frame  50  by a hinge  60 , allowing sub-frame  58  to tilt in the fore-aft plane to engage the bottom of container  200  as it is loaded onto carriage  14 . Rollers  56  and sub-frame  58  provide a broad support to the bottom of container  200 , so that it does not deform as it is loaded onto carriage  14 . In another embodiment, two parallel sets of rollers  56  and sub-frames  58  are mounted to either side of carriage  14  to provide more surface area to support container  200 .  
         [0035]      FIG. 5  shows an embodiment of rollers  56  and sub-frame  58  in a perspective view. Also shown is a guide  60  mounted to sub-frame  58  by one or more hinges  62 . As container  200  is pulled onto rollers  56 , guide  60  may be rotated upright to assure that the rear of the container is centered over frame  50  so that container  200  is securely supported. Actuator  64  rotates guide  60  upright, to an engaged position flush with sub-frame  58 , and rotates guide  60  outward, counter-clockwise as shown in  FIG. 5 , to a disengaged position so that the container can be lifted onto the rollers  56  in the event that container  200  is misaligned with the lift assembly  12 . In alternative embodiments, guide  60  may be mounted to frame  50  by hinges, or rigidly secured to sub-frame  58  or frame  50 .  
         [0036]      FIG. 7  shows another embodiment of the invention, where carriage  14  is embodied as a truck  65  having one or more drive wheels  66  and one or more steering wheels  68 . The entire assembly rests on support surface  204 .  
         [0037]     An embodiment of control system  16  is shown in  FIG. 6 , along with various elements of other systems controlled by control system  16 . Engine  70  drives a clutch  72 , which, when engaged, drives a transmission  74  and a differential  76  to turn drive wheels  66 . Engine  70  also drives a pump  78  and a pump  80  to provide pressurized working fluids to various actuators. In a preferred embodiment, pump  78  is a hydraulic pump, and pump  80  is a pneumatic pump. A power take-off unit (“PTO”)  82  is connected to transmission  74 . In a typical configuration, transmission  74  would transmit power to PTO  82 . Here, however, the pressurized working fluid delivered by pump  78  drives PTO  82 , which in turn drives transmission  74  and drive wheel  66 . In other words, to PTO  82  transmits power in the reverse of the typical mode of operation for a power take-off unit.  
         [0038]     Pump  78  drives working fluid through hoses  84  and a series of variable valves. The valves are connected in series starting with variable valve  86 , which is connected to and controls actuator  38 . Next, variable valve  88  is connected to actuator and controls  42 . Next, variable valve  90  is connected to and controls actuator  92 . Next, variable valve  94  is connected to and controls actuator  64 . And, finally, variable valve  96  is connected to PTO  82 .  
         [0039]     Control system  16  may also contain a series of switches to energize components in control system  16 . The switches conduct electrical current provided by a power source  98 . Power source  98  may be a battery; alternatively, power source  98  may be a generator, alternator, or the like. Switch  100  energizes solenoid  101  which engages and disengages power take-off unit  82 . Switch  102  energizes solenoid  104 , configuring a valve  106  to direct pressurized working fluid to valves  30  and setting the position of pins  28 . Switch  108  energizes solenoid  110 , setting the speed of engine  70 . When the solenoid  110  is de-energized, engine  70  runs at a default idle speed. When solenoid  110  is energized, engine  70  runs at a higher speed, called “high idle”, turning pumps  78  and  80  at a speed sufficient to power the various actuators. Switch  112  energizes solenoid  114 , activating brakes  116 . Brakes  116  may be hydraulic, pneumatic, electric, or other type of brakes. Switch  118  energizes solenoid  120 , engaging clutch  72 .  
         [0040]     In alternative embodiments, solenoids  102 ,  104 ,  110 ,  114 ,  120 ,  110  and  116  may be replaced with any actuator capable of performing the desired function. Also, each solenoid and the device it controls may be replaced by an equivalent electrically operated component. For example, solenoid  104  and valve  106  may be replaced by an electrically operated valve, solenoid  114  and brake  116  may be replaced by an electrically operated brake, and so forth. For clarity, the polarity and operation of the switches is described so that closing a switch engages or operates a component; however, any switch may be wired so that opposite polarity or opening a switch may engage or operated a component.  
         [0041]      FIG. 11  shows the steps necessary to load a container onto lift mechanism  8  using the present invention. In step  122 , the engagement assembly  10  engages the front end of the container  200 .  FIG. 7  shows the position of container  200  and engagement assembly  10  after it is engaged to the container. Reference arrow  202  shows the position of the rear end of container  200  relative to the surface on which it rests. Continuing in  FIG. 11  at step  124 , lift assembly  10  raises the front of container  200 . In step  126 , carriage  14  is moved rearward. While carriage  14  is in motion, lift assembly  12  moves corresponding to the motion of carriage  14  so that the rear of container  200  remains in contact with the ground and does not move. In step  128 , a determination is made whether carriage  14  has contacted container  200 . If container  200  is not in contact, operation continues with step  126 . When carriage  14  contacts container  200 , the motion of carriage  14  is halted in step  130 . The position of carriage  14  at step  130  is shown in  FIG. 8 . Continuing in  FIG. 11  at step  132 , lift structure  12  continues to operate, pulling container  200  forward onto carriage  14 . As container  200  moves forward, the rear end of container  200  rises, as shown in  FIG. 9 . Continuing in  FIG. 11 , step  134 , lift structure  14  continues to move until container  200  until a determination is made that container  200  is approximately level, ready for transport. Once container  200  is level, the process stops in step  136 .  
         [0042]     A human operator may operate control system  16  to execute the steps shown in  FIG. 11 . Referring to  FIG. 6 , switch  118  is set to disengage clutch  72 . Switch  108  is set to place engine  70  in high idle mode. Switch  102  is set to place pins  28  in a disengaged position. Switch  100  is set to engage the power take-off unit  82 . Variable valves  86  and  88  are positioned to operate actuators  38  and  42  respectively, positioning arm  34 , lift arm  36  and bridle  20  so that pins  26  are engaged with corresponding holes in the front of container  200 . Now, switch  102  is set to place pins  28  to engage corresponding holes in the side of container  200 , securely engaging engagement assembly  10  to container  200 . This state corresponds to the result of step  122 .  
         [0043]     Typically, valve  94  is positioned to cause actuators  64  to open guides  60  to perform step  122 . However, if carriage  14  is adequately aligned with the long axis of container  200 , guide  60  may be left in the closed position to help guide container  200  as it is loaded.  
         [0044]     Valve  88  is configured to raise the front of container  200  with arm  34 , corresponding to step  124 . Variable valve  86  is then configured to continue lifting the container with arm  36 , while variable valve  96  is configured to energize PTO  82 , moving carriage  14  rearward. This state corresponds to step  126  in  FIG. 11 .  
         [0045]     In a preferred embodiment, variable valve  96  is downstream of variable valve  86  so that as variable valve  86  is configured to increase the speed of actuator  38 , less pressurized working fluid is available to PTO  82 , slowing down the motion of carriage  14 . This inverse relationship between the fluid delivered to actuator  38  and the fluid delivered to PTO  82  allows the operator to be somewhat imprecise in configuring variable valve  86  relative to variable valve  96  to match the speed of lift assembly  12  to carriage  14 , while still ensuring that the rear end of container  200  does not slide along the support surface.  
         [0046]     As carriage  14  moves, variable valve  90  may be operated to control actuator  92 , steering the support unit  14  to align it with container  200 . As carriage  14  moves rearward, it will contact container  200 , corresponding step  128  in  FIG. 11 . In an embodiment shown in  FIG. 5 , rollers  56  mounted to sub-frame  58  will contact the bottom of container  200 . Sub-frame  58  will tilt so that all the rollers  56  come into contact, providing a broad area of support for container  200  as it is lifted from the support surface  204 .  
         [0047]     When all rollers  56  contact container  200 , valve  96  is closed so that the carriage  14  halts, corresponding to step  130 . As a precaution, switch  112  may be set to energize brakes  114  to assure that the carriage remains halted.  
         [0048]     Variable valve  86  is positioned to energize actuator  38  to pull container  200  forward so that its weight is support entirely on rollers  56  and sub-frame  58 . As container  200  moves forward, the rear of container  200  leaves contact with the support surface, corresponding to the position shown in  FIG. 9  and step  132  in  FIG. 11 . Motion continues until container  200  becomes approximately level, corresponding to step  134  in  FIG. 11 . Variable valve  86  is then closed to bring the container to a halt, corresponding to step  136  in  FIG. 11 . The final position of container  200  is shown in  FIG. 10 , where the rear of container  200  is supported primarily by rollers  56 , and the front is supported primarily by the engagement assembly  10 . In an alternative embodiment, container  200  may rest on frame  50  rather than be supported by lift assembly  10 .  
         [0049]     At any time during the steps described in  FIG. 11 , the operator may discretionarily use valve  88  to control the position of engagement assembly  10  relative to lift assembly  14 . The valves and switches included in control system  16  allow the operator considerable flexibility in loading container  200  so that no portion of the container slides along the support surface. Flexibility of control is particularly required when the support surface is uneven or sloped.  
         [0050]     To unload container  200  from lift mechanism  8 , the steps shown in  FIG. 11  and described above are performed roughly in reverse order.  
         [0051]     While the controls in control system  16  operable by a human operator described above are simple and effective, they may be optionally replaced by electrically operated components controlled by a programmable computer  146 , containing a central processing unit  148  and memory  150 , as shown in  FIG. 12 . A computerized embodiment of control system  16  eliminates the need for careful monitoring and control by a human operator. Alternatively, the electrically operated components may be controlled by electronic circuitry other than a computer, such as circuitry based on programmable array logic or the like.  
         [0052]     In an embodiment shown in  FIG. 10 , engagement assembly  10 , lift assembly  12 , moveable carriage  14 , and control system  16  may be combined into a single apparatus  142 , called a lift truck, excluding container  200 .  FIG. 10  also shows an optional operator&#39;s console  140 , wherein the valve and switches in control system  16  may be located for convenient access by human operator. Alternatively, the operator&#39;s console may be located in the cab of lift truck  142 .  
         [0053]     A lift truck is particularly useful when loading and transporting a trailer. Referring to  FIG. 10 , lift truck  142  may be fitted with a hitch  144 . In one embodiment, hitch  144  is a fifth-wheel type trailer hitch. Lift truck  142  is connected via hitch  144  to an external trailer (not shown) having a trailer bed at approximately the same height as the bottom container  200 . Lift assembly  12  may be operated to push container  200  from its loaded position on lift truck  142  onto the trailer bed. As it is moved rearward, container  200  rolls along rollers  56 , and actuators  38  and  42  are operated to keep the angle of container  200  approximately level as container  200  moves from lift truck  142  to the trailer. Once container  200  is on the trailer, engagement assembly  10  disengages from container  200 , and lift assembly  12  positions itself and engagement assembly  10  over the carriage  14 , clear of the trailer. To unload the trailer, the steps are performed in reverse order.  
         [0054]     In a practical freight loading operation, containers may be loaded from the ground onto a lift truck, then from the lift truck back to a trailer. The lift truck then tows the loaded trailer to its ultimate storage location. The lift truck may be used to load and unload containers in a compact area without damaging the surface on which the freight loading operation is performed. Such loading and unloading operations often must be performed in locations such as department store loading zones and in personal storage unit providers, where the surface is not prepared for heavy duty freight loading operations.  
         [0055]     The exemplary embodiments shown in the figures and described above illustrate but do not limit the invention. Other forms, details, and embodiments may be made and implemented. Hence, the foregoing description should not be construed to limit the scope of the invention, which is defined in the following claims.