Abstract:
A handling system for incorporation in a trailer is used with palletized freight. The handling system incorporates a segmented, translatable platform. Among the segments is a principal or main segment which supports the palletized freight during shipping. The main upper surface of each of the segments is a conveyor. The conveyors are aligned from segment to segment to allow cooperative movement, respacing and unloading of the palletized freight on and between the segments and off of an end segment. The platform translation system allows the platform to be extended from an open end or side of the trailer. The segmentation of the platform allows the end and a mid segment to lower a piece of palletized freight to a surface below the level of the main segment of the platform.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The invention relates to an onboard load transfer system for trucks which minimizes the direct labor requirements for off loading cargo from truck trailers.  
         [0003]     2. Description of the Problem  
         [0004]     The off loading of cargo from a truck is typically intensive in its use of labor and materials handling equipment. Loading docks are frequently understaffed and under equipped, at least for handling peak traffic periods, and the lack of equipment and personnel often delays truckers. Sometimes deliveries must be made to locations with no dock at all. Various automated or semi-automated solutions have been proposed for loading and off loading truck trailers, but the implementation of many of these proposals requires an increased capital investment in dock facilities. Dock facility operators who are already operating their docks with a minimum investment in equipment, and with as few workers as possible, and thus are the cause of the delays, would seem to have little economic incentive to invest in such equipment since its financial benefit would primarily flow to the truck operators. Nor is there any assurance of standardization between docks implementing solutions that would work for all trucks.  
         [0005]     Fewer solutions to this problem have been directed to the truck trailer. Trailers of course present constraints on space and weight capacity for carrying elaborate materials handling systems. Any onboard solution must fit on or within the trailer and should not pose an excessive weight penalty. There is also the need to meet the demands of off loading trucks at different types of dock facilities, or a complete lack of a dock.  
       SUMMARY OF THE INVENTION  
       [0006]     According to the invention there is provided a handling system for incorporation in a trailer for use with palletized freight. The handling system incorporates a segmented, translatable platform. Among the segments is a principal or main segment which supports the palletized freight during shipping. The main upper surface of each of the segments is a conveyor. The conveyors are aligned from segment to segment to allow cooperative movement, respacing and offloading of the palletized freight on and between the segments and off of an end segment. The platform translation system allows the platform to be extended from an open end or side of the trailer. The segmentation of the platform allows use of the end and a mid segment to lower a piece of palletized freight to a surface below the level of the main segment of the platform.  
         [0007]     Additional effects, features and advantages will be apparent in the written description that follows. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:  
         [0009]      FIG. 1  is a perspective view in partial cutaway of a trailer illustrating operation of a preferred embodiment of the invention.  
         [0010]      FIG. 2  is a perspective view in partial cutaway of a trailer further illustrating operation of the preferred embodiment in different environment.  
         [0011]      FIG. 3  is a perspective view illustrating horizontal translation of the palletized freight handling system of the invention and the vertical repositioning of segments thereof.  
         [0012]      FIG. 4  is a side elevation of the same processes of  FIG. 3 .  
         [0013]      FIG. 5  is a side elevation of the translatable platform of a preferred embodiment of the invention.  
         [0014]      FIG. 6  is a side elevation of the translatable platform of the preferred embodiment as installed on a trailer having height a height adjusting suspension system.  
         [0015]      FIG. 7  is a side elevation of the translatable platform extended from a trailer as used to reposition palletized freight.  
         [0016]      FIG. 8  is a top plan view of a trailer bed on which the translatable platform has been installed.  
         [0017]      FIG. 9  is a cross sectional view of a wheel assembly for supporting the platform in a track on a trailer bed.  
         [0018]      FIG. 10  is a cross sectional view of a segment-to-segment joint allowing rotation about a horizontal axis.  
         [0019]      FIG. 11  is a schematic illustration of use of the platform to move and unload palletized freight.  
         [0020]      FIG. 12  is a schematic of a control system for the palletized freight handling system. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     Referring now to the figures and in particular to  FIGS. 1 and 2 , a trailer  10  incorporating a translatable, segmented platform  11  for palletized freight is shown. Translatable platform  11  is, in its retracted position within trailer  10  and fully supported on the bed of the trailer (see  FIGS. 8, 9 ) and may be repositioned as a unit off the bed through an opening in the trailer, such as end opening  17 . As shown in  FIG. 1 , the portion of translatable, segmented platform  11  moved out of the trailer may come to rest on the upper or target surface  13  of a raised loading dock  15 . Translatable, segmented platform  11  provides a support floor for a plurality of palletized freight modules  19 . The preferred embodiment of the invention works best with freight that is bundled into standard sizes with a standard orientation, here termed palletized units, although it is not intended that the invention as claimed be limited to freight of such character.  
         [0022]     Translatable, segmented platform  11  comprises three segments in the preferred embodiment, including an end segment  21 , a mid segment  23  and a main segment  25 . Each segment has a distinct function and each segment has its own, independently actuable conveyor. These include an end segment conveyor  27  and a mid segment conveyor  31 . End segment  21  is articulated with mid segment  23  along adjacent edges and mid segment  23  is articulated with main segment  25  along common edges. The axes of articulation are parallel and horizontally disposed allowing mid segment  23  to be rotated downwardly from one end of main segment  27  and end segment  21  to be rotated upwardly from one edge of mid segment  23 . Hydraulic pistons including hydraulic piston  35 , connected between mid segment  23  and end segment  21 , are used to rotate the segments. This allows end segment  21  to be lowered to and placed parallel on a supporting surface  33  while remaining flat. End conveyor  27 , mid segment conveyor  31  and the conveyor for main segment  25  are aligned for cooperation and may be operated in a fashion to separate the end or “current last in” palletized unit  19  from the remaining units. This separation allows the current last in palletized unit to lowered to the target surface  33  on segment  21  and moved off of end segment  21  at end  29 .  
         [0023]     Referring now to  FIGS. 3 and 4  translation and positioning of the segments of platform  11  is illustrated. Translation of the segments occurs as a unit, that is platform  11  may be moved horizontally in and out trailer  10  from a fully retracted position (A) on bed  13 , to an intermediate position (B) and finally to a position of maximum extension (C) where only a small portion of the platform remains in trailer  10  and supported on the bed. Translation occurs through an opening in the trailer, typically at one end of the trailer, although it is conceivable that it could be done toward a side of the trailer. Platform  11  is illustrated in a reconfigured shape (D) where mid segment  23  has been rotated in a clockwise direction A as viewed in  FIG. 5  and end segment  21  has been simultaneously and synchronously rotated in a counterclockwise direction B to drop the level of end segment  21  below the level of main segment  25 . Hydraulic pistons  35  and  37  are pivotally coupled between end segment  21  and mid segment  23  (for piston  35 ) and mid segment  23  and main segment  25  (for piston  37 ). Contraction of the pistons operates to introduce a fold in the platform  11  as illustrated in  FIG. 5 , while extension of the pistons straightens the platform. Strain on midsegment  23  is minimized by providing that the points of attachment of hydraulic pistons  35  and  37  on midsegment  23  are collocated.  
         [0024]     As illustrated in  FIG. 6 , translatable, segmented platform  11  is installed on the bed  47  of trailer  10 , and is preferably made as compact as possible in the vertical dimension to minimize the amount of space occupied. Freight is preferably kept on main segment  25  during shipping, but the trailer may be filled, with cargo carried on all of the segments if the destination has a raised dock. Otherwise, enough of platform  11  must be kept clear of cargo to allow mid segment  23  to be cleared of pallets for rotation out of the horizontal when it is necessary to lower end segment  21 . It is conceivable that platform  11  could be adapted to fold end segment  21  and mid segment  23  upwardly within trailer  10  to conserve space, or that the two segments could be detached from the main segment and carried beneath the bed. Either adaptation can be expected to add considerable mechanical complexity to the system.  
         [0025]     Conveyors can operate simultaneously with translation of the translatable, segmented platform  11 . As illustrated in  FIG. 7 , platform  11  is being withdrawn into trailer  10  in the direction indicated by the letter B while end conveyor  27  moves a pallet  19  off the end of the platform. Preferably the velocity of platform  11  cancels the velocity of the upper surface of conveyor  27  relative to the ground so that the velocity of the current last in palletized object  19  is also zero relative to the surface on to which it is transferred. Simultaneously, the remaining palletized objects  19  are moved toward the opposite end of platform  11  at the same time the platform is withdrawn into the trailer. Motion may be ramped up and down to avoid tumbling the cargo on account of its inertia.  
         [0026]     Translation of platform  11  is preferably confined to a straight line. Referring to  FIG. 8 , it may be seen that platform  11 , within trailer  10 , rolls along parallel tracks  45  running lengthwise along the bed  13  of trailer  10 . Translatable, segmented platform  11  may be moved by any number of devices. Here a translation mechanism  43  is provided by an elongated worm gear coupled into the main segment  25 . Conveyors  27 ,  31  and  41  are located to provide the upper surfaces of end segment  21 , mid segment  23  and main segment  25 , respectively. The worm gear translation mechanism is coupled to main segment  25  below the level of conveyor  41 . The conveyors are aligned on one another and travel on parallel axles allowing packages to be freely moved from one conveyor to an adjacent conveyor.  
         [0027]     Each segment of translatable, segmented platform  11  comes with a plurality of wheel assemblies  51  such as illustrated in  FIG. 9  which extend from the sides (or from the bottoms of the segments along the sides) of the segments aligned with the direction of travel of the platform. Wheel assemblies  51  are set in the tracks  45  allowing to and fro movement of platform  11  in the direction of elongation of the tracks.  
         [0028]     Referring to  FIG. 10 a  hinge or joint  53  providing articulation between main segment  25  and mid segment  23  is illustrated. Joint  53  is located along the lower surfaces of the segments and toward the outside edge of the segments allowing mid segment to articulate downwardly from main segment  25 . A similar joint is provided between mid segment  23  and end segment  21 , except that it is located along the top surfaces, outside of the conveyors, allowing the end segment  21  to rotate upwardly from the mid segment.  
         [0029]     Operation of the translatable, segmented platform  11  is illustrated in  FIG. 11 . Operation is typically done by the truck operator using a control interface positioned to allow the process to be directly watched. At step A an array of palletized freight units  19  designated A-D are situated on main segment  25  of translatable, segmented platform  11 . This is a preferred position for the palletized units  19  during shipping. Where the destination is a facility that requires use of platform  11  to lower palletized units  19  enough space must be left on platform  11  to allow the palletized units to be positioned so that mid segment  23  is clear of any units. One palletized unit  19  is positioned on end segment  21  during lowering operation.  
         [0030]     Moving to step B the process of repositioning palletized units  19  is illustrated. Conveyors installed on main segment  25 , mid segment  23  and end segment  21  operate to move all four palletized units toward the end segment. Once the current last in palletized unit  19 , designated A, is fully off of main segment  25 , the conveyor for main segment  25  stops while the conveyors for mid segment  23  and end segment  21  continue to run until the current last in palletized unit  19  is fully off of the mid segment and preferably positioned centered on end segment  21  as illustrated in step C.  
         [0031]     The palletized unit  19  disposed on end segment  21  may or may not need to be lowered to ground level. The process is illustrated as including a lowering step D. Mid segment  23  is pulled by pneumatic actuators  37  contracting to rotate the segment counter-clockwise as indicated at H. Simultaneously, end segment  21  is kept level by retraction of pneumatic actuators  35 , the segment rotating clockwise synchronously with mid segment  23  as indicated by the letter  1 . Sensors may disposed on the bottom of end segment  21  to determine when the segment is fully supported from underneath. Next, at step E, translatable, segmented platform  11  is withdrawn in the direction indicated by the letter K while the conveyor for end segment operates to move the “A” palletized unit  19  off of the end of end segment  21 . Palletized unit  19  preferably has a zero velocity relative to the target surface.  
         [0032]     Referring to  FIG. 12 a  control system  55  is illustrated in schematic form for a preferred embodiment of the invention. Control system  55  relates primarily to positioning and articulation of translatable, segmented platform  11 , and the movement of the conveyors  27 ,  31  and  41 , but also provides for transferring information to a trailer suspension control system for adjusting the height of trailer  10 . Control system  55  is primarily directed to control of hydraulic actuators, but those skilled in the art will comprehend that the system can be applied to non-hydraulic systems. The central component of control system  55  is a programmable microcontroller  57  which receives requests for operation of system elements over a data bus  61  to which it is coupled and which transmits requests from a user interface  67 . User interface  67  may be implemented in any number of ways, and may be made configurable to reflect the character of the system elements using a touch screen.  
         [0033]     Hydraulic fluid is stored in a reservoir  59  and delivered by a hydraulic circuit to pumps  71  and  72 . Pump  71  supports operation of the conveyors  27 ,  31  and  41 . The hydraulic circuit supporting conveyor operation includes three valve bodies  73 ,  74  and  75  which deliver fluid to hydraulic motors  79 , 80  and  81 , respectively, to operate motors  79 - 81  in either of two directions. Since each motor is controlled by its own valve body, the motion of the conveyors may be coordinated, or independent of the remaining conveyors. A valve controller  65  coupled to data bus  61  controls operation of the valve bodies  73 - 75  under instruction of microcontroller  57 .  
         [0034]     Hydraulic fluid is also pressurized by a second hydraulic pump  72  which provides hydraulic fluid to valve bodies  76  and  77 , which are used to control the extension and retraction of pneumatic arms  35  and  37 . Valve controller  65  is also used for controlling valve bodies  76  and  77 .  
         [0035]     Translation of platform  11  is performed by a translation mechanism  43 , which may be implemented in a worm gear arrangement or other mechanical arrangement for converting rotational motion of a motor  87  to linear movement. Additional motors  83  and  85  are provided for pumps  71  and  72 , respectively. All three motors are under the control of a motor controller  63 . Motor controller  63  operates under the control of microcontroller  57 . Feedback to the operator over interface  67  may be provided by the inclusion of sensors which generate information relating to the position of packages on the platform, support of the platform from below, or extent of extension of platform  11 . To this end various pressure sensors  89 A-B, position sensors  91  A-C and translation extension sensor  93  may be provided. Pressure sensors  89 A and B may provide operational information relating to status of the hydraulic circuits. Position sensors  91 A-C may be various types of transducers used to locate palletized units  19  or the location of segments. Lastly, data bus  61  is coupled, either directly or indirectly, to a trailer suspension control system  69  to allow the trailer height to be adjusted to bring the bed of the trailer level with a raised dock.  
         [0036]     The invention provides a compact, on board cargo handling system for a trailer which is useable at both improved and unimproved locations for unloading of cargo. While not directed to cargo loading, the system can be used to reposition cargo on board without the need to drive a forklift truck onto the bed of the vehicle.  
         [0037]     While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.