Delivery vehicle with multi-tier storage of cargo

A cargo delivery vehicle is described having storage for multiple tiers, or levels, of cargo. The delivery vehicle includes two or more interior elevating platforms, at least one on either side of a center structural wall running parallel to the side walls. Substantially continuous side access doors provide total exterior access to the lowermost tier of cargo. Cargo stored at the upper tier may be positioned by an elevating means at the level of the lower tier for either rear loading or side retrieval purposes. The center structural wall supports a transverse roof truss system that carries suspended outboard loads inward to the center wall. This non-traditional framing system greatly reduces the structural requirements of the side walls and floor, thereby permitting largely open framing for multiple side access ports as well as a minimized floor thickness to permit easier access from the pavement.

BACKGROUND OF THE INVENTION 
The invention relates to cargo delivery vehicles. More particularly, the 
invention relates to cargo delivery vehicles having multiple tiers of 
cargo storage which can be easily accessed for loading purposes through 
the rear doors, and can be unloaded through side access doors without 
requiring total bodily entry into the delivery vehicle in order to 
retrieve any portion of the cargo. 
It is desirable to store and transport a wide variety of cargo in vehicles 
having multiple storage tiers so that the most efficient use of the 
interior space in the vehicle can be made. In many distribution 
industries, single-tier delivery vehicles suffer from several 
disadvantages resulting in the inability to utilize the full vertical 
capacity of the cargo area. One such disadvantage is that stacking cargo 
to excessive heights introduces potential payload instability. A second 
disadvantage is that excessive stacking often results in cumbersome access 
for manual unloading. A third disadvantage of excessive cargo stacking is 
that upper cargo may crush lower cargo. The structure of an upper tier 
cargo platform acts as a shelf by keeping the weight of the upper cargo 
from damaging crushable lower cargo, thus allowing a delivery vehicle to 
minimize its wheelbase and turning radius by carrying an increased payload 
capacity in weight per unit of area. 
It is also desirable in many distribution applications to utilize a 
delivery vehicle engineered to provide the structural versatility to both 
(1) accept palletized cargo through rear doors, as from a warehouse dock, 
and (2) permit total and random side access to cargo at multiple delivery 
stops without the inefficiencies or hazards associated with unloading 
personnel being required to enter the vehicle in order to effect total 
cargo retrieval. 
Typically, the features of rear loading and random-access side unloading 
are mutually exclusive in the known art of enclosed delivery vehicle 
construction. Some delivery vehicles in the food service industry provide 
rear loading with only limited side access, thus requiring total bodily 
entry into the vehicle in order to fully unload. This arrangement may 
achieve advantageous loading capabilities, yet suffer from unloading 
inefficiencies. Conversely, delivery vehicles common to the beverage 
distribution industry often permit total exterior access to the cargo 
areas through multiple side doors for unloading, but structurally and 
logistically prohibit rear loading. 
It is still further desirable to provide an elevating means for raising and 
lowering segmented upper tier cargo platforms such that both an upper and 
lower tier may be loaded or unloaded from the lower level. Total exterior 
access to all cargo may be preferably achieved via side doors permitting 
access to multiple sections of the lower level. The elevating means may 
then provide the capability to lower upper tier cargo to the 
side-accessible lower level for retrieval. 
Mutli-tier storage of cargo is well known in the art. For example, it is 
known to provide upper and lower fixed storage platforms in a multi-tier 
cargo storage vehicle, as described in U.S. Pat. No. 4,139,109 issued Feb. 
13, 1989 to Murphy. A single rear elevator apparatus used to vertically 
transfer cargo between fixed tiers, as disclosed in the patent to Murphy, 
possesses the disadvantage that a fixed upper tier cargo platform may 
prohibit loading personnel from entering the rear of the vehicle to 
facilitate the forward conveyance of cargo through the interior of the 
vehicle. Likewise, cargo vehicles with fixed tiers can not provide random 
access to all tiers of cargo through side access doors positioned at the 
lowermost tier. 
A variety of specialized interior elevator arrangements have been developed 
to overcome the disadvantages of exterior lift mechanisms and fixed tiers 
for multi-tier storage. For example, U.S. Pat. No. 2,832,636 issued Apr. 
29, 1958 to Black, discloses the use of a single interior elevator 
platform extending the length of the cargo storage space, which enables 
the transportation of cargo in two tiers. Segmented platforms formed by 
multiple adjoining elevators have also been proposed, such as in U.S. Pat. 
No. 4,701,086 issued Oct. 20, 1987 to Thorndyke. These segmented platforms 
provide two-tier storage in certain segments and single-tier storage in 
other segments where tall cargo is to be stored. A similar segmented 
platform lift apparatus in a multi-tier double drop trailer has been 
disclosed in U.S. Pat. No. 5,092,721 issued Mar. 3, 1992 to Prince. 
But these vehicles with interior elevators are structurally limited to 
receiving and delivering cargo through rear doors only. As in the 
arrangement shown by Murphy, the forward cargo is inaccessible while the 
aft cargo is in place. Such an arrangement may provide a spatially 
efficient means of transporting cargo between destinations; however, they 
may be ill-suited for adaptation to delivery applications in which cargo 
retrieval efficiency is a primary concern. Modern distribution systems 
frequently require the transportation of cargo from a warehouse to 
multiple delivery stops where unloading efficiency can be greatly enhanced 
by direct and random access to the entire lower tier through a series of 
side doors and where an elevating means can also position upper tier cargo 
platforms at the lower tier level. 
A further disadvantage of the vehicles disclosed by Black, Thorndyke, and 
Prince is that they have elevating cargo platforms that extend 
transversely the full width of the vehicles' interior. Although full-width 
elevating platforms can thereby accept cargo up to eight feet wide, it may 
be more desirable for cargo portions to be longitudinally divided and 
independently accessible such that cargo placed within a lower tier cargo 
portion must reside within the average workman's arm's reach, so that his 
body may remain substantially outside of the delivery vehicle. 
Accordingly, half-width elevating platforms may reduce the workman's 
susceptibility to fatigue and injury, since he need not bodily enter the 
vehicle to load or unload cargo. 
In conventional enclosed delivery vehicles having single-tier or multi-tier 
storage, the floor is typically required to bear the weight of the cargo 
and transfer those forces longitudinally through either floor or side wall 
members to the vehicle's axles. The requirement for numerous, closely 
spaced structural members in the side walls may limit the availability of 
sizable doors for cargo access from the side of the vehicle. Some 
conventional vehicles offer limited side access through doors penetrating 
the side walls, but such doors are necessarily limited because of the 
structural compromises they create. Therefore, it is desirable to minimize 
the load-bearing requirements of the side walls of the delivery vehicle in 
order to afford virtually continuous side access to the cargo. 
Moreover, in the construction of enclosed delivery vehicles, the 
load-bearing floor is typically required to be quite thick for adequate 
structural support, thereby decreasing the interior space for storage. 
Therefore, it is also desirable to minimize the load-bearing requirements 
of the floor of the delivery vehicle in order to maximize interior storage 
space, especially space located in the ergonomically advantageous lower 
zone of the trailer. 
Accordingly, it is an object of the present invention to provide multi-tier 
cargo storage in a delivery vehicle. 
It is a further object of the invention to provide an enclosed, multi-tier 
delivery vehicle which can be loaded completely through rear doors of the 
vehicle and unloaded completely through side doors of the vehicle. 
A still further object of the invention is to provide an enclosed, 
multi-tier delivery vehicle which permits direct and simultaneous exterior 
access to cargo located at the lowermost tier. 
A still further object of the invention is to provide an enclosed, 
multi-tier delivery vehicle with multiple side access ports through which 
the entirety of the cargo can be manually unloaded without requiring 
unloading personnel to bodily enter the vehicle. 
A still further object of the invention is to provide an enclosed, 
multi-tier delivery vehicle in which all tiers can be loaded and unloaded 
at the lowermost tier. 
A still further object of the invention is to provide an enclosed, 
multi-tier delivery vehicle in which the cargo storage area is 
longitudinally bisected in order that cargo portions may remain within 
arm's reach of a side wall access door. 
A still further object of the invention is to provide an enclosed, 
multi-tier delivery vehicle in which the load-bearing requirements placed 
on the side walls and floor are substantially reduced, permitting greater 
side access to cargo, and minimizing the vertical height of the floor. 
SUMMARY OF THE INVENTION 
The invention provides improved loading and unloading capability for cargo 
delivery vehicles. According to one aspect of the invention, there is 
provided an enclosed transport vehicle having at least an upper and lower 
tier in vertical alignment for cargo storage. An upper tier cargo platform 
may be lowered with an elevating means in order to facilitate loading or 
unloading cargo stored on said platform at a level approximating said 
lower tier. 
According to a second aspect of the invention, there is provided an 
enclosed transport vehicle having a plurality of independently operable 
elevating cargo platforms of the type described in which the interior 
cargo storage area is longitudinally bisected by a center structural wall 
such that said elevating cargo platforms adjoin other elevating cargo 
platforms transversely across said center wall and at least one other 
elevating cargo platform in a longitudinal direction. 
According to a third aspect of the invention, there is provided an enclosed 
transport vehicle having a plurality of adjoining elevating cargo 
platforms which is structurally capable of accepting cargo loaded through 
rear access doors while also permitting simultaneous exterior access to 
cargo unloaded through a plurality of side access doors. 
According to a fourth aspect of the invention, there is provided an 
enclosed transport vehicle having a plurality of adjoining elevating cargo 
platforms and multiple side access ports which can be entirely and 
manually unloaded through the sides without requiring unloading personnel 
to completely enter the vehicle's interior in order to retrieve any 
portion of the cargo. 
According to a fifth aspect of the invention, there is provided an enclosed 
transport vehicle having a plurality of adjoining elevating cargo 
platforms in which the load-bearing requirements of the side walls are 
substantially shifted to a longitudinally bisecting center wall which 
transfers loads longitudinally to the vehicle's axles. 
According to a sixth aspect of the invention, there is provided an enclosed 
transport vehicle having a plurality of adjoining elevating cargo 
platforms in which the load-bearing requirements of the floor are 
substantially shifted to transverse, overhead roof beams which carry 
outboard loads inward to the center structural wall, which in turn 
transfers loads longitudinally to the vehicle's axles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
In the preferred embodiment, the multi-tier delivery vehicle includes a 
plurality of independently operable, adjoining elevator assemblies for 
raising and lowering cargo such as pallets stacked with packages or 
merchandise. As shown in FIG. 1, delivery vehicle 2 is preferably embodied 
as a semi-articulated trailer that may be operatively coupled to a 
motorized tractor means for transport. The delivery vehicle 2 is enclosed 
by side walls 6 and roof 8 to protect cargo and vehicle mechanisms from 
the elements, and may preferably be insulated for use in the distribution 
of temperature sensitive food products. All cargo may be loaded through 
rear doors 10a and 10b, transported on either an upper or lower tier, and 
unloaded through multiple side access doors 12. These side access doors 12 
are preferably provided in each side wall 6 so as to permit substantially 
continuous exterior access to all cargo positioned at the lower tier 
level. The lower tier consists of cargo placed at or on the vehicle floor 
4, and every elevating platform 14 (FIG. 2a) may travel between the lower 
tier and upper tier. Specifically, elevating platform 14a is shown in FIG. 
1 positioned at the lower tier for receiving cargo through the rear or 
delivering cargo through the side. Elevating platform 14c is shown raised 
to an upper tier position for storage and transportation of cargo, and 
platform 14b is shown in motion midway between tiers. 
It will be readily apparent that the elevator assemblies described can be 
extended to three, four, or more platforms so as to provide more than two 
tiers of storage. The two-tiered version herein illustrated world be 
commonly employed for palletized cargo portions up to four or five feet in 
height. However, other types of cargo transported in shorter bins may 
permit the use of several storage tiers, and the elevating platforms 
herein described may be readily adapted by those skilled in the art to 
provide for greater numbers of storage tiers. 
The loading and unloading sequence can be more readily understood from 
FIGS. 2a through 2l. In FIG. 2a, delivery vehicle 2 is shown backed up and 
ready to receive cargo, as from a warehouse loading dock. Elevating 
platforms 14 and 14' are positioned at the lower tier to permit 
walk-through loading. Loading personnel may then manually push or 
otherwise steer cargo portions to convey cargo forward through the 
interior of the vehicle. Cargo bays on either side of the center 
structural wall 24 are loaded sequentially in a front to rear progression. 
FIG. 2b shows the start of a loading cycle of the rearmost cargo bays, as 
if all forward bays have been previously loaded in a similar fashion. Onto 
elevating platform 14 is loaded a first cargo pallet 16. In a manner 
hereinafter described, elevating platform 14 is raised to an upper tier 
position as shown in FIG. 2c. Beneath cargo pallet 16 may then be placed a 
second cargo pallet 18 onto the vehicle's floor 4 as shown in FIG. 2d. In 
FIG. 2e, a third cargo pallet 20 is loaded onto the elevating platform 14' 
in the bay transversely opposite the center structural wall 24. FIG. 2f 
shows third cargo pallet 20 raised on elevating platform 14' with an 
elevating means, allowing a fourth cargo pallet 22 to occupy the lower 
tier in FIG. 2g. 
In FIG. 2h, the delivery vehicle is loaded to capacity and ready to 
distribute cargo at multiple locations. Side access doors 12 provide 
access to each cargo bay at the lower tier level. FIG. 2l shows fourth 
cargo pallet 22 being unloaded through side access door 12 at a delivery 
stop. In FIG. 2j, the lower tier has been fully unloaded and the third 
cargo pallet 20 has been lowered for unloading. Likewise, on the opposite 
side of the vehicle, the second cargo pallet 18 may be unloaded through a 
side access door 12 as in FIG. 2k and then the first cargo pallet 16 
descended to occupy the accessible lower tier for further unloading as in 
FIG. 2l. 
It will be readily understood that the foregoing sequence can be reversed 
so that loading is accomplished through the side doors and unloading is 
accomplished through the rear doors. Likewise, it will be readily apparent 
that all loading and unloading may be performed through rear doors only. 
Also, it can be seen that all loading and unloading may be effected via 
side doors only. In summary, any combination of rear or side access is 
permitted for both loading and unloading cargo. 
The center structural wall 24 is nominally disposed so as to bisect the 
transverse dimension of the delivery vehicle, creating two cargo areas of 
roughly equal size. Because of the permanent longitudinal division created 
by the center structural wall 24, cargo portions are necessarily limited 
in transverse width to a dimension somewhat less than half of the legal 
over-the-road width regulation. Likewise, the use of cargo elevators to 
mechanically position all tiers of cargo in turn to the elevation of the 
lowermost tier restricts the vertical unloading height to a dimension 
somewhat less than half of the legal height limit plus half the height of 
the tires. Thus, all cargo may be mechanically positioned substantially 
within the average worker's arm's reach when the worker is standing on the 
pavement. Additionally, the provision of side access doors at every 
elevator bay for cargo retrieval permits manual access to the entire 
payload area without requiring total bodily entry into the vehicle. It is 
to be understood, however, that less than all of the cargo in the 
lowermost tier may be accessible through side access doors if it is not 
desired to furnish the vehicle with side access doors along its entire 
length. 
The preferred embodiment provides a substantially open side wall frame 
without paying the vertical height or gross vehicle weight penalty of a 
thick, load-bearing floor. Referring now to FIG. 3, a center structural 
wall 24 is provided which serves as the primary load-path carrying cargo 
and vehicle weight fore and aft longitudinally to the vehicle's axles. In 
this embodiment, the center wall 24 is constructed with clusters of 
vertical compression members which also incidentally serve as platform 
guide rails 28. Running longitudinally between and permanently affixed to 
these platform guide rails are two sheet metal stressed skins 26. These 
skins are spaced apart transversely to allow a polyurethane foam core 32 
to be added to provide greater rigidity and an insulated thermal bulkhead 
for accommodating multi-temperature cargo portions. Top chord 25 and 
bottom chord 27 connect the upper and lower ends of platform guide rails 
28, and the stressed skins 26 provide a diagonal tension load-path. Thus, 
the center structural wall 24 is able to bear loads as would a very deep, 
weight-efficient truss. The clusters of four platform guide rails 28 
acting together as a column at the intersection of four elevator bays 
provide a lightweight yet durable structural configuration with lateral 
stability for supporting loads on transverse roof trusses 30. 
Transverse roof trusses 30 placed directly over top chord 25 provide an 
overhead means for outboard loads to get inward to the center structural 
wall 24 and then fore or aft to get down to the tires. Elevating platforms 
14 are suspended from these transverse roof trusses 30 as well as all 
outboard platform guide rails 28. The benefit of such an arrangement is 
that even the weight of cargo placed directly on the vehicle floor 4 may 
find a load path to one of the transverse roof trusses 30 via the platform 
guide rails 28, resulting in a capacity to minimize the vertical height of 
the vehicle floor 4, and thus the total unloading height. Open web roof 
trusses are preferred to solid roof beams from the standpoint of 
weight-savings and for their capability to provide for an air circulation 
plenum in temperature-controlled delivery applications. 
An overhead plan view of the elevating platforms 14 and 14' is shown by 
FIG. 4 as they are constrained at the corners from side-to-side and 
front-to-back movement by the platform guide rails 28. The framing 
configuration reduces structural demands on the side walls, which 
translates to a substantially reduced requirement for steel or aluminum 
members inside the exterior walls. The platform guide rails 28 provide 
structural rigidity to the exterior walls while remaining inside the 
insulated enveloped defined by polyurethane foam cores 32. The result of 
such a construction is superior thermal integrity. 
Within the plane defined by the transverse roof trusses 30 may be placed 
the means for mechanically elevating the elevating platforms 14. FIG. 5 
shows an apparatus preferred for its reliability and simplicity. A 
remotely located hydraulic pump and reservoir provide fluid power on 
demand to actuate a hydraulic ram 34 (34' in the adjacent bay). As piston 
35 is retracted into cylinder body 37, drive cable 36 unwinds, thereby 
rotating windlass shaft 38 and causing slave cables 42 to coil around 
windlass drums 40 and take up an elevating platform 14. Four slave cables 
42 are attached to the four corners of each elevating platform 14. 
Corresponding components in the adjacent bay are represented by hydraulic 
ram 34', piston 35', cylinder body 37', drive cable 36', windlass shaft 
38', slave cables 42', and windlass drums 40'. 
Each slave cable 42 assists in bearing the weight of the upper tier cargo 
and transferring their gravity loads to transverse roof trusses 30 via 
pulleys 44 and windlass bearings 46. The hydraulic ram 34 is sufficiently 
powerful to overcome the mechanical disadvantage created by the drive 
cable 36 turning windlass shaft 38 of shorter radius than windlass drum 
40. The benefit of said mechanical disadvantage is that a short stroking 
piston 35 may multiply the distance that the slave cables 42 travel. Those 
skilled in the art will recognize that other lifts, such as electric 
winches, fluid-powered rotary actuators, or ball screw linear actuators, 
could also be used. 
While a particular embodiment of the invention has been illustrated and 
described, it will be obvious to those skilled in the art that various 
changes and modifications may be made without sacrificing the advantages 
provided by the principles of construction or methods disclosed herein.