Abstract:
A carrier adapted for mounting on a vehicle bed can carry cargo. The carrier has a stationary support mounted on the vehicle bed. The carrier also has an articulated support and a cargo support. The articulated support has a proximal end pivotally mounted on the stationary support. Also included is an elevation device coupled to the articulated support at an upper joint and to the stationary support at a lower joint for articulating the articulated support. The upper joint is further from the proximal end than the lower joint. The cargo support is mounted for longitudinal motion on the articulated support. The cargo support is operable to detach and reattach to the articulated support at a handoff location located at the proximal end of the articulated support. The carrier also has a motive device for moving the cargo support. This motive device includes a guide mechanism located at the handoff location for vertically translating and supporting an end of the cargo support from the handoff location.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to apparatus for transporting cargo, and in particular, to a device having a cargo support that can be articulated before unloading the cargo. 
     2. Description of Related Art 
     People often wish to transport equipment such as motorcycles or personal water craft with small trucks such as pickup trucks. A serious difficulty is lifting such equipment onto the truck bed. U.S. Pat. No. 5,249,910 proposes using a winch to load and unload cargo over a ramp. A ramp may be inappropriate for unloading equipment such as a personal water craft onto land. First, significant effort is required to push the craft horizontally across the truck bed and onto the ramp. Once on the ramp, one end of the craft can be brought to the ground, but must then be lifted and pulled out to allow the rest of the craft to descend the ramp. Alternatively, the truck can be moved forward as the craft completes its descent on the ramp, but this procedure is complicated and will normally require two operators. Also, loading can be difficult because the craft must pass the crest of the ramp and rapidly change its angle of elevation, before becoming horizontal on the truck bed. The rocking occurring at this transition also means that the full weight of the craft is supported essentially at a single point, which runs the risk of applying excessive pressure and damaging the hull. 
     Commercially available trucks for hauling vehicles include a platform that tilts before being slid backwardly to reach the ground and form a ramp. The cargo must still make the transition from the ground onto the ramp, which is not difficult with wheeled vehicles, but can be difficult with other cargo such as water craft. More importantly, this technology requires that the truck be dedicated to hauling vehicles and is therefore impractical for users who may wish to use their truck other purposes. U.S. Pat. No. 5,511,928 shows a boat hauling accessory that can be placed on an ordinary pickup truck, but has a platform that always stays tilted, so that the forward end remains high over the truck cab while traveling. Also, this arrangement does not solve the problem of moving the cargo from the ground to the platform. See U.S. Pat. No. 5,846,047 for a tilting platform that does not slide longitudinally. 
     In U.S. Pat. No. 5,603,600 a ramp is formed of two telescoping sections. Cargo can be loaded on one section of the ramp, which then slides upon the other section to lift the cargo up over the truck bed. The collapsed ramp then pivots into a horizontal position. This device does not solve the problem of lifting the cargo onto or off the ramp. Also, this device keeps the cargo high off the truck bed, apparently to accommodate the mechanism that rotates the ramp. Such a configuration, however, raises the center of gravity, and reduces the stability of the truck and its cargo. 
     In U.S. Pat. No. 5,380,141 a similar arrangement is shown where the first section deployed does not support the cargo, but is positioned behind the truck and supported by a separate vertical support member. Thereafter, the section carrying the cargo is slid over the already deployed member, and then both members can be tilted to form a ramp. This arrangement has the same difficulty with loading/unloading the cargo from/to the ground and also keeps the cargo high and therefore degrades stability. 
     In U.S. Pat. No. 5,232,329 one end of a detachable platform can be lifted by a cable suspended over a boom whose angle of elevation is controlled by a hydraulic cylinder. The boom is then swung from an obtuse angle to an acute angle to allow the detachable platform to ride up the boom. Swinging the boom through such a large angle requires a relatively long hydraulic cylinder, and for this reason, the boom and cargo remains high off the truck bed after loading. See also U.S. Pat. No. 5,620,296 for another boom arrangement. 
     Accordingly, there is in need for a cargo carrier that can be mounted on a vehicle bed and which simplifies the process of loading and unloading cargo. 
     SUMMARY OF THE INVENTION 
     In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a carrier adapted for mounting in a vehicle bed for carrying cargo. The carrier has a stationary support mounted on the vehicle bed. Also included is an articulated support and a cargo support. The articulated support has a proximal end pivotally mounted on the stationary support. The carrier also has an elevation means for articulating the articulated support. The cargo support is mounted for longitudinal motion on the articulated support. The cargo support is operable to detach and reattach to the articulated support at a handoff location located at the proximal end of the articulated support. The carrier also has a motive means for moving the cargo support. This motive means includes a guide means located at the handoff location for vertically translating and supporting an end of the cargo support from the handoff location. 
     In accordance with another aspect of the invention there is provided, a carrier adapted for mounting in a vehicle bed for carrying cargo. The carrier has a stationary support and an articulated support. The stationary support is mounted on the vehicle bed. The articulated support has a proximal end pivotally mounted on the stationary support. Also included is an elevation means coupled to the articulated support at an upper joint and to the stationary support at a lower joint for articulating the articulated support. The upper joint is further from the proximal end than the lower joint. The carrier also has a cargo support mounted for longitudinal motion on the articulated support. The cargo support is operable to detach and reattach to the articulated support at a handoff location located at the proximal end of the articulated support. The carrier also has a motive means for moving the cargo support. 
     By employing apparatus of the foregoing type, an improved cargo carrier is achieved. In a preferred embodiment, the cargo can be placed on a cargo support formed as a platform having casters at its four corners. This cargo platform can roll in channels of a preferred articulated support. These channels also have rollers at their back end. The angle of elevation of this articulated support can be altered by a hydraulic cylinder. This hydraulic cylinder connects below to a location that is relatively close to the pivot point of the articulated support (in comparison to the connection point of the cylinder to the articulated support itself). This relative placement of the hydraulic cylinder allows it to collapse into a nearly horizontal position, so that the cargo platform can descend to a position close to the truck bed in order to provide a low center of gravity and better stability. This role to placement also reduces the force and stresses placed on the articulated support. 
     In this preferred embodiment, the cargo platform can extend from the channels of the articulated support, and detach therefrom as the leading edge of the cargo platform touches the ground. Preferably, the descent is controlled by a winch-driven cable, which cable eventually rides over a sheave to lower the trailing edge of the detached cargo platform to the ground. Detachment of the cargo platform is facilitated by a hand lever located near the sheave. This lever can be used to lift the trailing edge of the cargo platform over the sheave and other parts of the articulated support. 
     In one highly preferred embodiment, the assembly can be detached from the truck bed using quick-release pins. Support legs can then be deployed to support the back end of the assembly. The assembly can then be partially unloaded from the truck bed before additional support legs on the forward end of the assembly are deployed to then allow complete unloading. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above brief description as well as other objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1A is a side elevational view of a carrier in accordance with principles of the present invention, mounted on a vehicle and carrying cargo in the form of a motorcycle; 
     FIG. 1B shows supports of the carrier of FIG. 1A articulated; 
     FIG. 1C shows the cargo support of the carrier of FIG. 1A partially deployed; 
     FIG. 1D shows the cargo support of FIG. 1C just detached from the main assembly; 
     FIG. 1E shows the cargo support of FIG. 1D lowered to the ground and with alternate cargo, namely, a personal water craft; 
     FIG. 2 is a perspective view of the carrier of FIG. 1E; 
     FIG. 3 is a plan view of the stationary support for the carrier of FIG. 2; 
     FIG. 4 is an exploded, detailed perspective view of an inside corner of the support of FIG. 3; 
     FIG. 5 is a plan view of the articulated support of the carrier of FIG. 2; 
     FIG. 6 is a fragmentary, detailed perspective view of the center of the distal edge of the support of FIG. 5; 
     FIG. 7 is an exploded, detailed perspective view of the left proximal corner of the support of FIG. 5; 
     FIG. 8 is a fragmentary, detailed plan view of a portion of the proximal edge of the support of FIG. 5; 
     FIG. 9 is a detailed elevational view of the proximal end of the arrangement of FIG. 7; 
     FIGS. 10A-10C are schematic diagrams showing the progression of the front end of the support of FIG. 11 over the assembly of FIG. 9; 
     FIG. 11 is a plan view of the underside of the cargo support of FIG. 2; 
     FIG. 12 is a fragmentary, detailed plan view of a side of the support of FIG. 11; 
     FIG. 13 is a cross-sectional view of a portion of the articulated support of FIG. 5 shown supporting the assembly of FIG. 12; 
     FIG. 14 is an elevational view of an assembly that is an alternate to that of FIG. 13; 
     FIG. 15A-15C are sequential elevational views of the carrier of FIG. 2 showing the deployment of legs that can facilitate removal from a vehicle; 
     FIG. 16 is a schematic illustration of an elevation means that is an alternate to that of FIG. 2; 
     FIG. 17 is a schematic illustration of an elevation means that is an alternate to that of FIG. 2; 
     FIG. 18 is a schematic illustration of an elevation means that is an alternate to that of FIG. 2; and 
     FIG. 19 is an exploded, perspective view of an articulated support and cargo support that is an alternate to that of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1A and 2, a vehicle  10  is shown supporting the carrier  12  on its bed  14 . The carrier has an articulated support  16  pivotally mounted on its proximal end to a stationary support  18 . Articulated support  16  has along its sides a pair of C-shaped channels  74  arranged to receive cargo support  20 . A motive means  22 , shown as a winch, is mounted in the center of the distal member  76  of articulated support  16  to act as a hoist means. Hoist means  22  can play out and rewind cable  24  (also referred to as a flexible link). 
     In FIG. 2 cargo support  20  is shown detached from articulated support  16  and coming to rest on the ground. Accordingly, cable  24  is shown passing over sheave  26 , which acts as a guide means located in a handoff location  27 . Cargo support  20  is shown with four casters  28 A- 28 D at its four corners. The vertical posts of hitching fence  30  are inserted into sockets (shown hereinafter) at the forward corners of cargo support  20 . The six tie-down cleats  32  are provided along the outside edges of support  20  for securing cargo. Also, a pair of optional longitudinal ribs  34  are mounted atop panel  36  to support, for example, the hull of a personal water craft (shown hereinafter). 
     An elevation means is shown herein as a pair of hydraulic cylinders  38 , each connected between stationary support  18  and articulated support  16 . The lower end of the elevation means  38  is connected to a lower joint  40  that is closer to the proximal end of support  16  than the upper joint  42  on the articulated support  16 . This offset between the upper and lower joints  40 ,  42  enable the articulated support  16  to descend to a position contiguous to stationary support  18 , at which time the elevation means  38  forms a relatively shallow angle of less than 10° with respect to horizontal. This enables the cargo to ride at a relatively low position, which keeps the center of gravity of the vehicle low to enhance stability. As described further hereinafter, this offset also reduces the stress on articulated support  16 . 
     As described further hereinafter, the detachment of cargo support  20  from articulated support  16  will be assisted by lever  44 , which acts as a lift means to boost the forward edge of cargo support  16  over sheave  26 . 
     Referring to FIGS. 3 and 4, stationary support  18  is shown with a longitudinally oriented pair of angle irons  46  welded at their forward ends to a similar, transverse angle iron  48 . Welded between the mid sections of angle irons  46  is a flat metal brace  50 . An electrically powered hydraulic pump  51  is shown attached to the side of one of the angle irons  46  to provide hydraulic pressure to the cylinders  38 . An L-shaped bracket  52  is welded to the outside of angle irons  46 . The knuckle  54  of hydraulic cylinder  38  is pinned between bracket  52  and angle iron  46 . 
     An L-shaped bracket  58  is welded to the inside edge of angle irons  46  near their forward ends. Bracket  58  presents a hook-like projection that can interlock with the previously mentioned cargo support to act as an interlock means for holding that cargo support in place when lowered. 
     Each of the forward ends of angle irons  46  has a support hole  60  that communicates into a box-like shield  62  attached to the inside corner of angle iron  48 . Angle iron  48  can fit into the inside corner of a bracket  64 , shown herein as an angle iron. A spaced pair of walls  66  are welded transversely to bracket  64 . Each of the walls  66  has a bracket hole  68 , aligned to receive locking pin  70 . Between walls  66 , pin  70  is fitted through holes in the arms of U-shaped leaf spring  72 , with the inner arm of spring  72  affixed to a mid point of pin  70  in order to inwardly bias the pin toward support hole  60 . Accordingly, the pins  70  can be withdrawn and the J-shaped outer handle of pins  70  turned into a position that keeps each pin withdrawn. Stationary support  18  can then be positioned with its support hole  60  aligned with bracket holes  68 . Thereafter, pins  70  can be released to lock support  18  onto bracket  64 . Of course, the procedure can be reversed when support  18  must be removed from bracket  64 . 
     Referring to FIGS. 5 and 6, articulated support  16  is shown with two parallel, longitudinally extending, C-shaped channels  74 . The distal ends of channels  74  are interconnected by a transverse channel  76 , while their proximal ends are interconnected by angle iron  78 . Welded into a cut-out in one of the branches of channel  76  (FIG. 6) is a short box extrusion  80  that acts as a socket for supporting the previously mentioned winch. 
     Referring to FIGS. 7-9, both branches  74 A and  74 B of channel  74  are shown cut back at the proximal end. A distal portion of the end of the horizontal branch  78 A of angle iron  78  is butt-welded to the inside edge of the lower branch  74 A of channel  74 . A vertical journal plate  82  is welded to the lower edge of web  74 C of angle channel  74 . Plate  82  has a rear hole  82 A aligned with the hole  84 A in vertical journal plate  84 , which is welded to the underside of the distal edge of branch  74 A. Plates  82  and  84  are designed to straddle the vertical branch of angle iron  46  (FIG. 4) of stationary support  18 . Consequently, channels  74  can be pivoted on the stationary support by means of a pivot provided by bolt  86 . 
     A vertical journal plate  88  welded to a vertical branch at the end of angle iron  78  has a hole  88 A that aligns with hole  82 B. An axle  89  (FIG. 8) can connect between holes  88 A and  82 B to support end roller  90 . A converging wall  92  is welded at an obtuse angle to the proximal end of web  74 C. 
     Referring to FIG. 8, a spaced, parallel pair of journal plates  94  are welded at the corner of angle iron  78 . Previously mentioned lever  44  is shown pivotally mounted between plates  94 . Lever  44  is shown with a rubber sleeve  45  acting as a handle. Previously mentioned sheave  26  is shown journalled in U-shaped cradle  96 , which is welded to the vertical face of angle iron  78 . 
     Referring to FIGS. 11 and 12, the underside of cargo support  20  is shown with a parallel pair of lateral members  98  in the form of a square tubes, each having both ends notched at their top and bottom faces to receive previously mentioned casters  28 A- 28 D. A forward member  102 , also in the form of a square tube, is welded to the ends of members  98  at their inside faces. An aft member  104 , in the form of a square tube, is welded between the inside faces of members  98  near their aft ends. Members  98 ,  102 ,  104  and  106  are covered by a panel  105  made of plywood, sheet plastic or metal, or other materials. 
     Four, square reinforcing tubes  106  are transversely welded between opposite faces of members  98 . A U-shaped hitch  107  is welded to the forward face of the second most forward one of the transverse tubes  106 . The previously mentioned cable (cable  24  of FIG. 2) can be attached to hitch  107 . 
     Two vertically oriented, short square tubes  108  are welded in the two inside corners formed between members  98  and  102  to form sockets that can hold such items as the previously mentioned fence (fence  30  of FIG.  2 ). Matching holes are formed in panel  105  to provide access to sockets  108  from the topside of cargo support  20 . Two more vertically oriented, short square tubes  110  are welded in the two outside corners formed between members  98  and  104  to form sockets for holding other items. 
     Referring to FIG. 13, cargo support  20  is shown riding inside channel  74  of articulated support  16 . Previously mentioned upper joint  42  is shown composed of a vertical plate  42 A welded to the outside of the web of channel  74 . An angle iron  42 B is welded to the top edge of plate  42 A to form a journal for supporting a pin  112 . Previously mentioned piston arm  38 A connects to pin  112  through knuckle  38 B. 
     Referring to FIG. 14, an alternate cargo support  20 ′ is shown with a top panel  105 ′ connected to a dependent skirt  116 . A roller  28 ′ is journalled on skirt  116  to roll inside channel  74 ′ of alternate articulated support  16 ′. With this arrangement certain relationships are reversed. Instead of being at equal heights, cargo support  20 ′ rides above articulated support  16 ′. Here, channel  74 ′ opens to the outside instead of to the inside. 
     Referring to FIG. 15A, carrier  12  is shown in its normal position extending from the back of vehicle  10 . Pivotally attached to each side of stationary support  18  are legs formed of telescopic members  118  and  120 . The distal end of member  120  is fitted with a caster  122 . Leg  118 ,  120  is telescopically collapsed when stored in a position parallel to stationary member  18 . When deployed, leg  118 ,  120  is swung in the direction indicated and locked into a vertical position. Telescopic member  120  can be extended to the extent necessary to bring caster  122  against the ground. 
     Referring to FIG. 15B, carrier  12  has been detached from vehicle  10  and retracted therefrom (by first manipulating pins  70  shown in FIG.  4 ). An operator can lift and pull the back end of carrier  12 . Alternatively, the carrier  12  can be held in place and the vehicle  10  driven forward to partially discharge carrier  12 . At this point, carrier  12  is supported on leg  118 ,  120  and the tail  10 A. Next, a leg  124 ,  126  (similar to leg  118 ,  120 ) is swung as indicated to a vertical position, from a stored position parallel to stationary support  18 . As before, leg members  124  and  126  are telescopically extended until caster  128  reaches the ground. At this point carrier  12  can be completely removed from vehicle  10  and supported on its legs  118 - 128  as shown in FIG.  15 C. Therefore, carrier  12  can be wheeled on casters  122  and  128  into a garage or other storage location. 
     Referring to FIG. 16, an alternate stationary support  18 ″ is attached to a vehicle. An alternate articulated support  16 ″ is pivotally mounted on stationary support  18 ″. The stationary support  18 ″ is similar to the previously mentioned stationary support, except that support  18 ″ is shortened in length and is just long enough to accommodate hydraulic cylinder  38 ″. In the previously described embodiments the stationary support extends further but does not provide any function. Therefore the shortening of stationary support  18 ″ is accomplished without losing any functionality. 
     Referring to FIG. 17, an alternate stationary support  18 ′″ is mounted in a vehicle bed in a manner similar to that previously described. An alternate articulated support  16 ′″ is pivotally mounted on stationary support  18 ′″. In this embodiment a pair of scissor arms  130  and  132  are pivotally connected at their proximal ends. The distal ends of arms  130  and  132  are pivotally attached to supports  16 ′ 41   and  18 ′ 41  , respectively. An alternate hydraulic cylinder  134  is connected between arms  130  and  132  to articulate them and thereby articulate support  16 ′″. This arrangement has the advantage that the articulated support  16 ′ 41   can descend to a position adjacent to support  18 ′ 41   and thereby lie near the vehicle bed. 
     FIG. 18 shows an alternate means for articulating the previously mentioned articulated support. Herein, the articulated support can be driven by a driven arm  136  pivotally mounted on journal  138 , which is affixed to support  140 . Lever arm  142  is integral with driven arm  136 , and is pivotally attached to one end of link  144 . The other end of link  144  is attached to the piston rod  146  of hydraulic cylinder  148 , which is affixed to support bracket  150 . Accordingly, hydraulic piston  148  can drive piston rod  146  and link  144  in the direction shown to pull lever and  142  and thereby rotate arm  136  in the direction indicated. 
     To facilitate an understanding of the principles associated with the foregoing apparatus, an operational sequence will now be briefly described. This operation will be described in connection with the embodiment of FIGS. 1-13, although it will be appreciated that the operation for other embodiments will be similar. It will be assumed that a motorcycle  11  has been stored atop cargo support  16  as shown in FIG.  1 A. The front wheel or fork of motorcycle  11  can be attached to hitch  31  (FIG. 2) in a conventional manner. Also, motorcycle  11  can be tied down using cleats  32 . 
     The operator can now start electrically powered hydraulic pump  51  (FIG. 3) to extend piston rod  38 A. Consequently, articulated support  16  will pivot on stationary support  18 , eventually rising to the position shown in FIG.  1 B. Significantly, the attachment point of piston rod  38 A is further from the pivot point of articulated support  16  than the attachment point of hydraulic cylinder  38 . As a result, the effective lever arm for support  16  is greater than that of support  18 . With this orientation, the force applied normally to stationary support  18  will be greater than that applied normally to articulated support  16 . However, stationary support  18  is supported by vehicle bed  14  and is therefore better able to handle this higher force. Also, less (or none) of the weight of motorcycle  11  will be cantilevered when piston rod  38 A acts at a distal position that is relatively remote from the pivot point of articulated support  16 . 
     Next, the operator starts winch  22  and plays out cable  24  to allow cargo support  20  to descend as shown in FIG.  1 C. During this descent front rollers  28 A and  28 B ride inside channel  74  as shown in part in FIG.  13 . Also, members  98  (FIG. 11) of cargo support  20  are supported by, and roll over, rollers  90  (FIGS.  8  and  9 ). It will be noted that the rollers  28 C,  28 D are about to touch the ground before cargo support  20  can detach from articulated support  16 . Thereafter, the operator can continue to play out cable  24  to deploy cargo support  20 , while simultaneously reducing the force of hydraulic cylinder  38  to allow adjustments in the angle of elevation as the cargo support prepares to detach. 
     Eventually, the front end of cargo support  20  reaches the handoff location and detaches from articulated support  16 , as shown in FIG.  1 D. The passage through the handoff location is illustrated in FIGS. 10A-10C. Up until the moment illustrated in FIG. 10A, cargo support  20  (specifically, its members  98  of FIG. 11) were riding on and supported by rollers  90 . Now the front casters  28 A,  28 B of the cargo support engage rollers  90  and begin to ride up as indicated in FIG.  10 A. To help the front casters  28 A,  28 B surmount the crest of rollers  90 , lever  44  (FIG. 8) may be lifted by its handle  45  to engage the underside of transverse member  102 . This assistance is sometimes necessary because the cable  24  can release but cannot push cargo support  20 . 
     Eventually as shown in FIG. 10B, front casters  28 A,  28 B past the crest of rollers  90 , at which time a leading corner of transverse member  102  engages the crest of sheave  26 . This means that transverse member  102  need not descend and ascend past a valley where it may get snagged trying to leave the valley. Accordingly, sheave  26  does not do any further lifting but allows transverse member  102  to pass and descend as shown in FIG.  10 C. 
     Cable  24  continues to play out and now rides on sheave  26  as shown in FIG.  2 . Accordingly, the forward end of cargo support  20  is eventually lowered to the ground to rest on its casters  28 A- 28 D. Cable  24  can now be disconnected from hitch  107  (FIG. 11) and the cargo support  20  can be wheeled away on the casters  28 A- 28 D. 
     As shown in FIG. 1E, new cargo has been loaded on cargo support  20 , namely, a personal water craft  15 . The hull of craft  15  can be centered between ribs  34  and its bow hitched to fence  30 . As before, the craft can be tied down for additional security. The operator can then power winch  22  to reel in cable  24  over sheave  26  to lift the front end of cargo support  20 . Cargo support  20  is guided into the channel  74  of articulated support  16  by guide plates  92  (FIGS.  2  and  7 ). 
     Eventually, transverse member  102  of cargo support reaches sheave  26  and climbs to its crest, as essentially shown in FIG. 10C, but with the motion now reversed. At this time, no assistance is required from lever  44  (FIG. 8) since the cable  24  can supply sufficient force to lift cargo support  20  and surmount any impediments. Transverse member  102  passes the crest of sheave  26  and reaches the position of FIG. 10B where forward casters  28 E,  28 B just touch rollers  90  at their crest (not before their crest). As before, this means that casters  28 A,  28 B need not descend and ascend past a valley where the casters may get snagged trying to leave the valley. Instead, casters  28 A,  28 B arrive at the crest of rollers  90  and descend thereon to the position shown in FIG.  10 A. 
     Cargo support  20  can now reverse the procedure previously described, moving to the successive positions shown in FIG. 1C, FIG. 1B, and then FIG.  1 A. When articulated support  16  fully descends against stationary support  18 , the vertical arms of brackets  58  (FIG. 3) interlock between transverse member  102  and the forwardmost one of the transverse members  106  (FIG. 11) to prevent cargo support  20  from sliding off articulated support  16 . 
     Referring to FIG. 19, the schematically illustrated, alternate cargo support  220  is designed to ride in schematically illustrated articulated support  216 . In this drawing, components that are functionally similar to previously illustrated components have the same reference numeral but increased by  200 . Here, the casters  228 A- 222 E of cargo support  220  ride inside channels  274  of articulated support  216 . The front and back ends of cargo support  220  are spanned by transverse shafts  302  and  304 , respectively. A handoff roller  330  is rotatably mounted on shaft  302 . Journal plates  282  welded to the underside of channels  274  rotatably support rollers  290 . A pair of handoff rollers  226  are rotatably mounted on shaft  291 , which is supported by journal plates  290 . 
     Rollers  290  normally support the underside of members  298  as cargo support  220  rolls inside channels  274 . Since shaft  304  never touches rollers  226 , they have no effect until cargo support  220  is about to detach from articulated support  216 . At that time, rollers  226  engage shaft  302 , at the same time that roller  330  engages shaft  291 . Consequently, the forward end of cargo support  220  must surmount a crest to attach or reattach to articulated support  216 , but will not pass through a valley where it can become snagged. 
     It is appreciated that various modifications may be implemented with respect to the above described, preferred embodiments. In some embodiments the articulated support will be lifted by a single hydraulic cylinder or by more than two hydraulic cylinders. Alternatively, the articulated support may be lifted by a hoist line or by drive gears located at the pivot point. Also, the cargo support may slide along the length of the articulated support using a variety of rail systems, interconnection systems, and in some embodiments may use an endless chain to accomplish the translation. In addition, the carrier can be made from a variety of materials and can have various dimensions and shapes depending upon the specific application. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.