Abstract:
An elevator delivery system is used with a truck body or trailer to facilitate loading and unloading cargo. The elevator delivery system includes a platform and drive mechanism for raising and/or lowering the platform. The platform is movable between an upright position between the walls of the truck body and an extended position extending from the truck body. A control system and various types of switches allow the operator to control the raising and lowering of the platform.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of patent application Ser. No. 10/351,812, which claims the benefit of U.S. provisional application Ser. No. 60/376,694 filed May 1, 2002, both of which are fully incorporated herein by reference. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates to loading and unloading cargo in a truck or trailer and more particularly, to an elevator delivery system for use in a truck body or trailer.  
       BACKGROUND INFORMATION  
       [0003]     Trucks have long been used to transport large amounts of cargo of various types. The truck bodies and trailers used to hold the cargo are typically designed to have a high clearance from the ground. Although the cargo can often be loaded easily into the truck bodies and trailers at a loading dock, the cargo is more difficult to load and unload from the ground. The drivers often must climb in and out of the truck to unload the cargo during deliveries. The additional labor required to unload the cargo may result in longer delivery times and more injuries to the delivery person.  
         [0004]     Various devices have been used to facilitate unloading the cargo, for example, ramps and hydraulic tailgates added to the rear of the truck or trailer chassis. Although these devices may help to unload the cargo, they often take additional time and labor to operate, for example, to pull out the ramp or to unfold the tailgate platform. Another device, known as the Lang doorway lift, uses a platform to lower or lift the cargo from the truck bed usually in a side door of the truck body. The Lang doorway lift, however, is operated using a single hydraulic cylinder and a complicated cable and pulley system. This cable and pulley system is inefficient and may be dangerous to the operator. Therefore, these existing devices for unloading cargo often do not make the delivery easier.  
         [0005]     Some elevator delivery systems include a platform that forms part of the truck bed. Although this type of elevator delivery system is effective, moving a section of the truck bed floor up and down has some disadvantages. When pallets are used, for example, the pallets cannot be positioned on the moving platform that forms part of the truck bed floor. Thus, the truck cannot be filled to capacity.  
         [0006]     Accordingly, there is a need for an elevator delivery system for use in a truck body or trailer that provides minimal interference with the cargo loaded on the truck bed.  
       SUMMARY  
       [0007]     In accordance with one aspect of the present invention, an elevator delivery system comprises a platform and a drive mechanism for moving the platform at least upward with respect to the truck body. The platform is pivotably coupled to the drive mechanism such that the platform folds into an upright position between walls of the truck body when the platform is in a raised position.  
         [0008]     In accordance with another aspect of the present invention, a combination truck body and elevator delivery system comprises an enclosed truck body having a bed, walls around the bed, and a door coupled to at least one of the walls for covering a doorway, and a platform mounted within the doorway such that the platform moves between an upright position between the walls of the truck bed and an extended position extending outward from the doorway. Drive mechanisms are mounted to the truck body on each side of the doorway for moving the platform at least upward with respect to the truck body. A control system controls the drive mechanisms.  
         [0009]     According to a further aspect of the present invention, an elevator delivery system comprises a platform and at least two hydraulic cylinder/piston mechanisms for moving the platform upward and downward with respect to the truck body. The hydraulic cylinder/piston mechanisms include at least two pistons mounted respectively on opposite sides of the platform and at least two hydraulic cylinders mounted to the truck body. The pistons move within the cylinders to move the platform relative to the truck body, and the platform pivots with respect to the pistons. A hydraulic control system supplies hydraulic fluid to the hydraulic cylinders to control the upward and downward movement of the platform. An inside switch actuates the hydraulic control system from a location inside of the truck body. The inside switch is located such that an operator of the inside switch is able to stand on the platform while the platform moves upward and downward. An outside switch actuates the hydraulic control system from a location outside of the truck body. The outside switch is located such that the platform is away from an operator of the outside switch. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     These and other features and advantages of the present invention will be better understood by reading the following detailed description, taken together with the drawings wherein:  
         [0011]      FIG. 1  is a perspective view of a truck body or trailer with an elevator delivery system, according to one embodiment of the present invention;  
         [0012]      FIG. 2  is a sectional perspective view of the elevator delivery system shown in  FIG. 1 ;  
         [0013]      FIG. 3  is a top schematic view of one embodiment of the elevator delivery system;  
         [0014]      FIG. 4  is a schematic view of one embodiment of the hydraulic control system used in the elevator delivery system;  
         [0015]      FIGS. 5A-5C  are rear views of a truck body, according to one embodiment of the present invention, illustrating one method of using the elevator delivery system to unload cargo;  
         [0016]      FIG. 6  is a perspective view of an elevator delivery system, according to a further embodiment of the present invention, with the platform in a raised extended position;  
         [0017]      FIG. 7  is a perspective view of the elevator delivery system shown in  FIG. 6  with the platform being moved to an upright position;  
         [0018]      FIG. 8  is a perspective view of the elevator delivery system shown in  FIG. 6  with the platform in an upright position;  
         [0019]      FIG. 9  is a perspective view of the elevator delivery system shown in  FIG. 6  with the platform in a lowered extended position;  
         [0020]      FIG. 10  is a side view of the elevator delivery system shown in  FIG. 6  with the platform in an upright raised position;  
         [0021]      FIG. 11  is a top schematic view of the platform coupled to the pistons in the elevator delivery system, according to the embodiment shown in  FIG. 6 ; and  
         [0022]      FIG. 12  is a side view of the platform in the upright and extended positions in the elevator delivery system, according to the embodiment shown in  FIG. 6 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     Referring to  FIG. 1 , an elevator delivery system  10 , according to one embodiment of the present invention, is located in a truck body  12  for moving cargo relative to the bed  14  of the truck body  12 . As used herein, the term “truck body” refers to both a non-detachable truck body and detachable truck body (e.g., trailer). In the exemplary embodiment, the elevator delivery system  10  is located between the walls  16  forming the rear doorway  18 , which is accessible by opening the door  19 . A portion of the exemplary elevator delivery system  10  extends beyond the walls  16  outside of the truck body  12 . Alternatively, the elevator delivery system  10  can be located at a side doorway or any other suitable location in the truck body  12 .  
         [0024]     Referring to  FIG. 2 , the elevator delivery system  10  comprises a platform  20  and at least two hydraulic cylinder/piston mechanisms  24   a ,  24   b . Each of the hydraulic cylinder/piston mechanisms  24   a ,  24   b  includes a piston  26   a ,  26   b  mounted to the platform  20  and a cylinder  28   a ,  28   b  mounted to the truck body  12  such that movement of the pistons  26   a ,  26   b  relative to the cylinders  28   a ,  28   b  causes movement of the platform  20  relative to the truck body  12 . The pistons  26   a ,  26   b  and cylinders  28   a ,  28   b  can be mounted using any known techniques (e.g., by using plates or other fixtures welded to the platform  20  and the truck body  12 ). In the exemplary embodiment, the pistons  26   a ,  26   b  are mounted at opposite sides of the platform  20 . Although the pistons  26   a ,  26   b  are shown mounted generally at a midpoint of the platform  20 , the pistons  26   a ,  26   b  can be mounted in other locations on the platform  20 . In the exemplary embodiment, the cylinders  28   a ,  28   b  are mounted to the bed  14  of the truck body  12 . The cylinders  28   a ,  28   b  can also be mounted to other locations, such as to the walls  16  (see  FIG. 1 ) of the truck body  12 . In a further embodiment (not shown), the cylinders  28   a ,  28   b  can be located within the walls  16  of the truck body  12 , thereby hiding the cylinders  28   a ,  28   b  and avoiding interference with the cargo.  
         [0025]     A hydraulic control system  30 , described in greater detail below, controls the supply of fluid to the hydraulic cylinder/piston mechanisms  24   a ,  24   b  and thus controls the movement of the platform  20 . The hydraulic control system  30  is preferably actuated from both inside and outside the truck body  12 . For example, an outside up/down switch  32  is located outside of the truck body  12  to allow the user to raise and/or lower the platform  20  from outside of the truck body  12 . The outside switch  32  is preferably in a location that keeps the user away from the platform  20  when it is being lowered. An inside up/down switch  34  is located inside the truck body to allow the user to raise and/or lower the platform  20  from inside the truck body  12 , for example, when standing on the platform  20 . Although the exemplary embodiment shows the hydraulic control system  30  in a location outside of and below the truck body  12 , the hydraulic control system  30  can be located in other locations inside or outside of the truck body  12 .  
         [0026]     The cylinders  28   a ,  28   b  are coupled to the hydraulic control system  30  by way of hydraulic lines  40   a ,  40   b . The hydraulic lines  40   a ,  40   b  are preferably in a location that will not interfere with loading and unloading cargo (e.g., under the truck bed  14 ). The outside switch  32  and the inside switch  34  are connected to the hydraulic control system  30  by way of wires  42 ,  44 , respectively. Other connections between the hydraulic control system  30  and the cylinders  28   a ,  28   b  and the switches  32 ,  34  are also contemplated.  
         [0027]     In one preferred embodiment, an edge switch  50  is located around the edge of the underside of the truck body  12  adjacent to the path of the moving platform  20 . The edge switch  50  is connected to the hydraulic control system  30  by way of wire  52 . The edge switch  50  provides an added safety feature when the platform  20  is being raised. If an object, such as the cargo or the driver&#39;s foot, is positioned between the platform  20  and the underside of the truck body  12  when the platform  20  is being raised, the object will actuate the edge switch  50 . Actuation of the edge switch  50  causes the hydraulic control system  30  to preferably move the platform  20  downward to avoid damage or injury.  
         [0028]     In another preferred embodiment, an audible alarm  54  alerts the operator that the platform  20  is being raised and/or lowered. The audible alarm  54  can be connected to the hydraulic control system  30  and located in any location that permits the alarm to be heard near the elevator delivery system  10 .  
         [0029]     One embodiment of the truck body  12  preferably includes bracing  60  surrounding the platform region  62 , which receives the platform  20  in the raised position. A lower portion  64  of the bracing  60  is preferably tapered such that an object (e.g., the driver&#39;s toe) that comes into contact with the tapered lower portion  64  will slide out of the way to avoid damage or injury. In this embodiment, the edge switch  50  is located beneath the tapered lower portion  64  of the bracing  60 . A rubber seal (not shown) can be provided along the top portion of the bracing  60  to seal against the platform  20  when raised. One embodiment of the platform  20  includes a ramp surface  66  at one side to allow cargo to be more easily wheeled off of the platform  20 .  
         [0030]     Referring to  FIG. 3 , an exemplary embodiment of the elevator delivery system  10  is shown schematically. In the exemplary embodiment, the truck body  12  includes 8″ structural steel channels forming the bracing  60 . The exemplary hydraulic cylinders  28   a ,  28   b  supported on the channels are single acting hydraulic cylinders having a bore of about 2½″ and a length of about 77″. The tapered lower portion  64  of the bracing  60  is a formed as a section having a width of about 5″ flared out at about 45° under the channels. The exemplary platform  20  is made of 1″ steel having a dimension of about 48″ by 44″ and having a 2″ by 2″ bracing.  
         [0031]     Referring to  FIG. 4 , an exemplary embodiment of the hydraulic control system  30  is shown schematically. According to this embodiment, the hydraulic control system  30  includes an electric hydraulic pump  72  with an electric solenoid  74  and a dump valve  76 . In one example, the pump  72  is a pump having a rating of about 2500 psi, such as the type available under the name Monarch from Monarch Hydraulics. The wires  42 ,  44  connect the solenoid  74  to the outside switch  32  and the inside switch  34  (see  FIG. 2 ), respectively, and the wire  52  connects the dump valve  76  to the edge switch  50 . The wire  88  connects the electric hydraulic pump  72  to a power source such as the vehicle battery (not shown). The pump  72  is connected to a tank  80  (e.g., a 3 gallon tank) that supplies hydraulic fluid to the pump  72 . A flow divider valve  82  is connected to the pump  72  by way of a hydraulic line  84  and connects the pump  72  to the hydraulic lines  40   a ,  40   b  from the cylinders  28   a ,  28   b . The hydraulic control system  30  is preferably housed in an enclosure  86  that protects and allows access to the hydraulic control system  30 .  
         [0032]     In response to signals from the up/down switches  32 ,  34 , the solenoid  74  actuates the pump  72  to pump hydraulic fluid through the lines  40   a ,  40   b  to or from the hydraulic cylinders  28   a ,  28   b  to lower or raise the platform  20 . The flow divider valve  82  evenly distributes the hydraulic fluid pressure between the hydraulic cylinders  28   a ,  28   b  to maintain the platform  20  in a substantially level position when a load is being raised or lowered, thereby preventing the hydraulic cylinder/piston mechanisms  24   a ,  24   b  from binding. In response to the edge switch  50 , the dump valve  76  is actuated causing the platform  20  to drop. In one embodiment, the elevator delivery system  10  at a back door of the truck body is capable of lifting about 2500 lbs. or more and the elevator delivery system  10  at a side door of the truck body is capable of lifting about 1500 lbs. or more, although this is not a limitation of the present invention.  
         [0033]     In use, the platform  20  can be raised or lowered using either the outside switch  32  or the inside switch  34 . Referring to  FIGS. 5A-5C , one method of using the elevator delivery system  10  is described in greater detail. At the beginning of a delivery, the driver  92  can open the door  19  and drop the platform  20 , for example, using the outside switch  32  ( FIG. 5A ). The driver  92  can then ride up on the platform  20  into the truck body  12  (using the inside switch  34 ) to load the cargo  90  onto the platform  20  ( FIG. 5B ). When the platform  20  is loaded with the cargo  90 , the driver  92  can lower the platform  20  and the cargo  90 , for example, using the inside switch  34  ( FIG. 5C ). This process can be repeated until the delivery is completed. Thus, the driver  92  can use the elevator delivery system  20  to avoid having to climb in and out of the truck when making deliveries.  
         [0034]     Accordingly, the elevator delivery system  10  is relatively easy to operate compared to existing devices and thus facilitates the unloading and loading of cargo into a truck or trailer. The elevator delivery system  10  also has fewer moving parts and thus operates more efficiently and reliably than existing hydraulic tailgate and lift devices. The elevator delivery system  10  further provides a number of additional safety features to avoid injury to the operator. For example, the location of the inside switch and the outside switch  32 , the edge switch  50 , and the audible alarm  54  all provide safety features that will minimize injuries caused by using the elevator delivery system  10 .  
         [0035]     Referring to  FIGS. 6-12 , a further embodiment of an elevator delivery system  110  used in a truck body  112  is described in greater detail. This embodiment of the elevator delivery system  110  includes a platform  120  that moves between an extended position shown in  FIG. 6  and an upright position shown in  FIG. 8 . In the upright position, the platform  120  is positioned between the walls  116  of the truck body  112  and preferably flush with the walls  116 . When the platform  120  is moved to the extended position, the platform  120  extends outward from the truck bed  114  for loading. When in the extended position, the platform  120  can be moved between a raised position ( FIG. 6 ) and a lowered position ( FIG. 9 ).  
         [0036]     The platform  120  is coupled to a drive mechanism  124  ( FIG. 7 ), such as a hydraulic cylinder/piston mechanism including a piston  126  and cylinder  128  on each side of the platform  120  to move the platform  120  between the raised position and the lowered position. The hydraulic cylinders  128  can be similar to those described above but are preferably double acting hydraulic cylinders capable of hydraulically moving the platform  120  downward as well as upward. The exemplary embodiment of the elevator delivery system  110  also includes a hydraulic control system (not shown) similar to that disclosed above but preferably with two flow dividers to provide the downward hydraulic movement in addition to upward movement. The elevator delivery system  110  can also include the switches and other features similar to those described above in connection with other embodiments.  
         [0037]     The platform  120  is preferably coupled to the pistons  126  in a manner that allows the platform  120  to pivot between the upright and extended positions, as shown in  FIGS. 10-12 . In the exemplary embodiment, a shaft  102  extends through the platform  120  and is coupled at each end to the pistons  126  using brackets  104 ,  105  or other coupling devices known to those skilled in the art. Roller bearings  106 ,  108  are mounted to the platform  120  and are rotatably mounted on the shaft  102 , allowing the platform  120  to pivot from the upright position to the extended position ( FIG. 12 ). The platform  120  preferably includes a stop tab  150  that abuts a hard stop bar  152  or other rigid structure to maintain the platform  120  substantially horizontal in the extended position ( FIG. 12 ). The platform  120  can also include a reinforcement bracket  154  to provide additional reinforcement in the middle region of the platform  120 .  
         [0038]     In one example, the platform  120  is made of aluminum and is about 44″ by 32″. Other materials and sizes are also contemplated. Where the platform  120  is made of a light-weight material such as aluminum, the drive mechanism  124  preferably moves the platform  120  downward. Where the platform  120  is made of a heavier material, gravity can move the platform  120  downward without being driven by the drive mechanism  124 .  
         [0039]     The elevator delivery system  110  further includes foldable side rails  130  coupled between sides of the platform  120  and the walls  116  of the truck body, as a safety feature. The foldable side rails  130  include a first folding side bar  132  pivotably coupled to the side of the platform  120  and a second folding side bar  134  pivotably coupled to the first folding side bar  132 . The second folding side bar  134  is pivotably coupled to a sliding bar  136 . The sliding bar  136  can move freely or can be slidably mounted to the wall  116 . In one example, the bars  132 ,  134  are flat bars made of steel. A chain or other similar structure (not shown) can be coupled between the foldable side rails  130  to provide an additional safety feature across the front of the platform  120 .  
         [0040]     In the exemplary embodiment, the elevator delivery system  110  is located in a side doorway  118  of a truck body  112 , although other locations are contemplated. Because the platform  120  does not form part of the floor of the truck bed  114 , the elevator delivery system  110  can be operated without interfering with pallets or other cargo stacked at the doorway.  
         [0041]     Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.