Stackable tray

A stackable tray includes a generally planar tray bottom and a pair of opposed side walls extending upwardly therefrom. A pair of rails extend downwardly from the bottom and lie generally below the side walls. Ridges are provided at the bottom of the rails and slots and support edges are provided adjacent the side walls to permit the trays to be stacked in a variety of configurations. The H-design of the trays of the present invention improves stacking and stability characteristics.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to the art of trays and in 
particular to stackable trays which may be used to contain, transport and 
display a variety of food and other products. 
2. Description of the Prior Art 
Various types of trays, baskets and tote boxes are commonly utilized to 
transport products at production facilities and to and from the 
distribution system. Such trays and baskets are especially common in the 
food industry. For example, bakeries use such trays to transport bread 
products to grocery stores. Produce distributors use them to transport 
produce, and butchers use them to transport portioned meat. 
In the bakery industry, trays are typically used for transporting bread, 
and baskets are used for transporting buns, cakes, pastry, rolls, etc. The 
trays and baskets may be interchangeable, but as a rule, this only occurs 
when there is a temporary shortage of a specific tray or basket. These 
types of trays or baskets may be constructed of wire form, steel draw 
forms or molded plastic and are manufactured in a variety of sizes and 
heights to accommodate a wide variety of products. As a general rule, such 
trays and baskets may be stacked for reasons which will be discussed later 
in this specification. 
Greater detail will now be provided concerning the trays and baskets used 
in the bakery industry. It should be understood at the outset, however, 
that such description is provided for purposes of illustration rather than 
for limitation. One skilled in the art could readily adapt the principles 
of the present invention to a wide variety of food and non-food items 
after reading the present specification. For example, many industrial 
applications exist where stackable trays may be used to convey parts or 
components from one part of a plant to another part of a plant or such 
stackable trays may be used to store completed parts or assemblies. Many 
of the problems encountered with prior art bakery trays and baskets are 
also encountered in such industrial applications, so the present invention 
will be equally applicable thereto. 
Common bread trays are about 20-22 inches in width, 26-30 inches in length 
and are about 1-1.5 inches high. They are similar in many ways to common 
cafeteria type trays, with diverging front, rear and side walls to permit 
nesting (similar to the way paper cups nest). The baskets most commonly 
employed are constructed of wire and have measurements similar to bread 
trays but come in a variety of heights to accommodate the particular type 
of bakery product they are designed to hold, for example, between about 
21/2-51/2 inches. These wireform baskets do not nest the way bread trays 
do, but instead they stack. 
Bakery trays and baskets are employed in the manufacturing plant to contain 
and transport product on conveyor lines and in mobile carts known as 
halfracks. They are also used in automatic and manual handling systems at 
the shipping docks at the plant. 
Halfracks usually hold about 28 trays or baskets and are loaded at the 
plant for subsequent delivery of the product to semi-trailers or delivery 
vans. Smaller vans and route trucks also typically have a halfrack 
arrangement, but these are not mobile. Instead, they are permanently 
mounted in the interior storage area of the truck or van. Such halfracks 
are generally quite heavy and their elimination would result in reduced 
fuel consumption and a consequent savings in product transportation cost. 
Once the bakery trays or baskets leave the plant, they continue to be used 
in the transportation and product distribution system. Loaded halfracks 
are moved from a conveyor system onto the semi-trailers where they are 
delivered to route trucks. At this point the trays or baskets are loaded 
into the route trucks to transport the goods to wholesale or retail 
outlets. At the sales outlet, the trays or baskets are used to carry the 
product from the trucks to the display area and are frequently used for 
on-floor display. If not, the trays and baskets are unloaded and the empty 
trays are loaded back on the route trucks. 
To fully appreciate the importance of the trays or baskets in the product 
distribution system, it is necessary to first understand that the business 
is one of extremely high volume, where cost and efficiency have a great 
impact on profitability. It is most advantegeous to load delivery trucks 
to maximum capacity. But it must also be remembered that the delivery 
trucks pick up return baskets or trays on a daily basis to feed them back 
into the product handling system. The logistics of the system can easily 
be upset as illustrated by the following example. If a fully loaded truck 
makes its first delivery and unloads ten trays or baskets, but finds 
twenty empty trays or baskets, an impossible situation exists unless the 
trays or baskets have some nesting capability. The random sequence of 
delivering loaded trays and picking up empty trays makes this problem one 
which is encountered on a daily basis. 
Some commercially available trays have moving parts to provide a nesting 
capability. However, because trays and baskets are handled so frequently, 
such trays or baskets can easily become damaged. Plastic baskets are 
available with moving flaps to provide various stacking heights, but 
damage to one of the moving parts will render the entire tray unusable for 
its intended function. Further, some trays or baskets are available which 
achieve various stacking heights through rotation of the basket by 
90.degree. or 180.degree.. The handling of such baskets requires 
additional time, thereby decreasing the overall efficiency of the 
distribution system. 
Several of such trays are described in issued U.S. Letters Patents Wilson, 
in his U.S. Letters Pat. No. 4,308,954, issued Jan. 5, 1982 for "Plastic 
Nestable-Stackable Receptacle", describes a tray for bakery or other 
products which may be stacked without the need to slide or rotate the 
receptacles with respect to one another. The tray is generally U-shaped 
and includes a plurality of projections which extend upwardly from the top 
of the side walls and several rows of slots in the side walls and below 
the projections. The trays may be stacked one on top of the other or 
nested by inserting the projections of a lower tray into the slots of the 
upper tray. The height is selected by the row of slots chosen. This patent 
does not relate to baskets or trays which may be stacked or nested at more 
than two heights. Furthermore, the projections and slots can be damaged 
during use, preventing the nesting or stacking capability, and the 
alignment of projections with slots requires time which decreases 
distribution system efficiency. 
Thurman, in his U.S. Letters Pat. No. 4,238,032, issued Dec. 9, 1980 for 
"Three-Position Stacking Tray", describes a tray which again is generally 
U-shaped and which includes a series of parallel but angled ribs on each 
of the tray's side walls. Each rib includes a notch on a side surface, 
approximately half way between the top and the bottom of the tray. The 
ribs of one side are also arranged in mirror relationship to the ribs on 
the other side. The three height capability is accomplished by reversing 
the trays 180.degree. for one height and by the type of vertical movement 
employed when the trays are assembled. The reversal of tray orientation 
and manipulation in assembly (to ensure that the notches seat property) is 
time consuming and reduces the efficiency of distribution involving such 
trays. 
Another multi-position container is described in the Carroll et al. U.S. 
Letters Pat. Nos. 4,102,453 and 4,320,837 issued respectively on July 25, 
1978 and Mar. 23, 1982 for "Nesting and Stacking Containers." These 
patents also describe U-shaped trays which include features which permit 
the trays to be stacked in three positions without rotating one container 
with respect to another. This is accomplished by providing side walls 
having an upper rail and a plurality of bars extending along the outside 
of the side walls and inclined downwardly, each bar having a stacking foot 
formed on the bottom thereof. The top of each bar forms a stacking saddle. 
The angle of each bar is selected so that the foot of one bar can nest in 
the saddle of an adjacent bar to provide a high-nest stacking position. 
The lowermost stacking position is accomplished when the bars slide 
between one another. An intermediate position is made possible by 
providing stacking supports intermediate the ends of the bars which are 
cup-like supports and act like the saddles described above. A back wall of 
the tray also includes inclined bars to assist in the stacking. The 
Carroll device is quite complex and the inclined bars and various saddle 
supports are subject to damage rendering the trays useless. Furthermore, 
the alignment of the trays to obtain the desired stocking height is 
relatively time consuming. 
Wilson describes a "Meat Lug" in U.S. Letters Pat. No. 3,027,045 issued 
Mar. 27, 1962 which is capable of being stacked at two levels. The lug has 
four ribs molded into its side walls and a pair of notches formed in the 
top surface of the lug on either side of the ribs. The lugs are nested by 
having the ribs slide into the ribs of a lower lug and are stacked by 
placing the bottom of the ribs of the upper tray into the notches of a 
lower tray. In the stacking positions, the lugs are alternatively placed 
in different ones of the pair of notches to maintain stability. The lugs 
cannot be stacked at three levels. 
Finally, Sanders et al., in U.S. Letters Pat. No. 4,000,817 issued Jan. 4, 
1977 describe a "Three Level Stacking Container" which includes stacking 
feet formed on an exterior tray wall and saddles on the top of the 
interior of the walls and at two levels for supporting the feet. The feet 
are generally L-shaped and the determination of the stacking level is 
established by the orientation of the trays. In addition, the trays must 
be tilted somewhat to accomplish insertion of the feet into the saddles. 
The Sanders et al. tray is also generally U-shaped. 
A tray which overcomes the aforementioned disadvantage of the prior art 
would represent a significant advance in this art. Ideally, such a tray 
should nest at its lowest stacking height, should have at least three 
stacking heights, should allow for maximum product visability and 
accessability, should be stable when stacked, should be adaptable to 
current conveyor and product handling systems, should have durability, 
should have no moving parts and should be as light in weight as possible. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is a primary object of the present invention to provide a tray or basket 
which overcomes the aforementioned disadvantages of the prior art and 
which satisfies the requirements for an improved tray set forth above. 
Another object of the present invention is to provide a tray having three 
stacking heights including a nesting capability. 
Yet another object of the present invention is to provide a tray which is 
light in weight and durable and which will function with minor damage. 
Still another object of the present invention is to provide a tray which 
has an H-design and which allows maximum product visibility and 
accessability. 
A different object of the present invention is to provide a tray having no 
moving parts and which can be easily and quickly stacked into any of its 
stacking configurations. 
Another object of the present invention is to provide a tray which is 
compatible with current conveyor, transportation and product distribution 
systems. 
How these and other objects of the invention are accomplished will be 
described in the following specification, taken in conjunction with the 
drawings. Generally, however, the objects are accomplished by a tray 
having an H-design rather than the U-design described above in connection 
with the prior art. In the preferred embodiment, the tray has a planar 
product supporting surface and side walls extending upwardly therefrom. 
Lower walls extend downwardly from the support surface below the side 
walls. The lower walls include a notched edge which is adapted to rest on 
the top of the side walls of the lower tray to provide a high stack 
capability. The tray of the preferred embodiment of the present invention 
also includes support edges adjacent the side walls and first slots to 
support the rails in an intermediate stack position, and second slots are 
also provided adjacent the side walls to receive the rails and provide a 
nesting position. Further variations of the invention will be described in 
the specification.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The tray 10 according to the preferred embodiment of the present invention 
includes a generally planar product support surface 12 which may be square 
or rectangular or may be of any other desired shape. The drawings show the 
surface 12 to be continuous, but it will be obvious to one skilled in the 
art that surface 12 may have holes, slots or other openings for weight 
reduction or aesthetic purposes (as illustrated at 13 in FIG. 1). It 
should also be stated at the outset that in the preferred embodiment, tray 
10 is preferably a unitary structure which may be molded from plastic or 
foamed plastic. The invention should not be limited thereto as one skilled 
in the art could readily select other construction techniques or materials 
for preparing tray 10. 
Tray 10 includes front wall 13 and rear wall 14 which preferably are low in 
height to increase product visiibility and accessability. These walls 
extend upwardly from surface 12 and may be continuous or may include 
openings as described above. Side walls 15 are also provided. They are 
higher than walls 13 and 14 and are separated from product support surface 
12 by a generally rectangular portion 16 which extends along the inside of 
each of side walls 15. Portion 16 includes an inner edge 17 having a 
height similar to the front and back walls, edges 17 together with the 
front wall 13 and back wall 14 defining the product holding area of tray 
10. Portion 16 also includes a pair of elongate slots 20 and 22 which are 
parallel to side walls 15. Slot 20 is wider than slot 22 and preferably 
has an open bottom for a reason which will soon become apparent. The 
purpose of the slots and the precise arrangement thereof will become 
apparent later in the specification. 
Outside the slots 20 and 22, the side walls 15 extend vertically upward 
from portion 16. The side walls 15 are inset slightly from the outer edges 
27 of tray 10. Side walls 15 terminate in rounded corners 29. The top of 
corners 29 and side walls 15 define a plane which is parallel to and above 
the planes established by the top of portions 16 and by product support 
surface 12. 
A horizontal support edge 32 is formed between the outside of side walls 15 
and the side edges 27. Surface 32 is at a level which is slightly below 
the level of the top of portions 16 and thus the two horizontal edges 32 
lie in a plane which is parallel to and intermediate those planes 
established by support surface 12 and the tops of portions 16. 
The final components of tray 12 are a pair of lower walls 38 which extend 
downwardly from support surface 12 along the sides of tray 10. The outer 
surface of rails lie in the same vertical plane as the outside surface of 
side walls 15, while the inside surface of the lower walls each lie in a 
vertical plane which is inside but parallel to the plane of the inside 
surface of side walls 15. Furthermore, a foot 42 is formed at the bottom 
of lower walls 38 which extends along its length and is formed by an 
L-shaped notch having a vertical outward facing surface 45 and a 
horizontal downward facing surface 47. The lower walls 38 extend generally 
from front to back, but are shorter than the tray, beginning and ending 
inwardly of the corners 29. 
The spatial relationship of the slots and various side wall and lower wall 
components can be appreciated best by reference to FIG. 4 (a cross-section 
through the side wall), but it should be understood that the various 
dimensional relationships can be varied to accommodate various types of 
products and various of the aforementioned design criteria without 
departing from the intended scope of the invention. 
Now that the major components of tray 10 have been described, it is 
appropriate to describe the stacking capabilities thereof and then to 
describe variations which are deemed to fall within the scope of the 
present invention. Tray 10 may, of course, be used by itself with product 
supported on surface 12. The product is clearly visible because of the low 
front and back walls and the tray 10 can easily be handled because support 
surface 12 is elevated above the surface on which the tray rests. 
It will be more common, however, for tray 10 to be used with other like 
trays, whether such use be in the factory, in the transportation and 
distribution system or in the store. For products which exceed the height 
of the side walls 15, but which do not exceed in height the overall height 
of tray 10, a high stacking mode is employed. In this mode, a tray 10 is 
lowered directly onto another tray so that the downwardly facing surfaces 
47 of the rails 38 rest on the top of side walls 15 as shown in FIG. 5. 
This high stack position can accommodate a wide variety of products such 
as bread, rolls, cakes, etc. 
A second and intermediate stacking height is employed for shorter products 
such as pies, muffins, etc. This position is accomplished by again 
lowering one tray 10 onto another tray, but with a small lateral 
displacement. The front and back walls of tray 10 remain coplanar with the 
corresponding components of the lower tray during this maneuver. By 
reference to FIG. 6, it will be appreciated that one foot 42 of one tray 
will be secured in slot 22 of the lower tray while surface 47 of the other 
foot of the upper tray will be supported on side edge support surface 32. 
It should also be appreciated from FIG. 6 that the right to left movement 
to accomplish the intermediate stack height should be alternated as 
stacking progress to maintain balance and stability. 
The lowermost stack height or nesting configuration is accomplished 
similarly to the procedure just described and is illustrated in FIG. 7. 
Here the right to left movement is increased slightly so that one wall 58 
of the upper tray is dropped into a slot 20 of the lower tray. In this 
configuration, support for the opposite side of the tray is provided by 
the bottom of support surface 12 resting on the top of side wall 15 of the 
lower tray. Again for purposes of the improving stacking stability, the 
movements right and left should be alternated as shown in this figure. 
It should also be understood that with tray 10 a mix of stacking heights 
can also be accomplished by varying the amount of lateral movement as the 
trays are assembled, i.e. the nest height can be used for some trays, 
while high and/or intermediate stacking is employed for others. There are 
no moving parts and no need for adjusting parts to allow stackability. The 
unique H-design of trays 10 permits stacking of 20 or more trays, and in 
all configurations, the trays are interlocked in such a way that they can 
move neither right or left nor forward or backwards, whether the trays are 
loaded or unloaded. Disengagement is accomplished simply by lifting the 
upper tray from engagement with its supporting tray. 
Numerous variations of the present invention may be made without departing 
from its basic principles. For example, holes may be provided in feet 42 
to receive wheels so that a stack of trays may be rolled from one location 
to another. The lower walls or side walls may be segmented for further 
weight reduction. So while the present invention has been described by 
reference to a particular preferred embodiment, it is not to be so limited 
but is to be limited solely by the claims which follow: