Interlocking plastic shelving system

A shelving system including a plurality of parallel horizontally oriented shelves releasably and securely connected to four upright posts is disclosed. The releasable connection of the shelf to the post is achieved by use of corner connectors which fit into corner notches of the shelf. The corner connector includes a male segment and a female segment which mate to each other and fit into said post at step locator positions along the length of the post. Complimentary tooth and channel configurations of the mated corner connector and the corner notches of the shelf interlock the shelf to the corner connector and then to the post. The shelves are connectable to and releasable from the posts between shelves already mounted on the posts.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to shelving systems for storing food, 
medicines and other bulk items. More particularly, the present invention 
relates to a storage and transport system wherein shelves are adjustably 
mounted at selected locations along the height of posts supporting the 
shelves. The mounting between the post and the shelves interlocks the 
shelf to the post in a positive fashion that will support the weight of 
the shelf and merchandise stored thereon. 
2. Description of the Prior Art 
Many shelving systems are shown in the prior art including interlock 
structures at the corner of shelves to lock the shelf in position along 
vertical support posts. L. Maslow (U.S. Pat. No. 3,424,111) shows a split 
compression connector of frustoconical shape which split connector fits on 
a post and then through an aperture in a plastic shelf. The thickness of 
the shelf at the outer edges is greater than the thickness of a central 
area in Maslow. R. Bustos (U.S. Pat. No. Re. 28,293) teaches a plastic 
shelf construction mounted on uprights or posts inserted through an 
aperture in the shelf having a flat face and a tapered face. The shelf of 
Bustos is specifically contemplated for merchandise display, i.e., soft 
drink products. The shelf has a thickened periphery and a central grid 
portion. Another adjustable shelf patent to L. Maslow (U.S. Pat. No. 
3,604,369) has grooved uprights to engage a tapered face member of the 
shelf. A tapered sleeve slides into a frictional fit with the tapered face 
to secure the upright to the shelf. 
W. Nathan (U.S. Pat. No. 4,467,927), W. Heinrich (U.S. Pat. No. 3,845,864) 
and B. Weiss, et al. (U.S. Pat. No. 3,323,656) all teach various shelf 
constructions. Nathan shows a grid construction. Heinrich shows a foam 
core construction for a shelf. Weiss shows a corrugated shelf having 
multiple layers. 
J. Barry, Jr., et al. (U.S. Pat. No. 3,511,191), L. Dickens (U.S. Pat. No. 
4,240,557) and R. Bustos, et al. (U.S. Pat. No. 3,939,987) all teach 
various plastic foam pallet and shelf supports that are of general 
interest. 
An extruded plastic shelf assembly, including wall portions and shelf 
portions is seen in M. Kurokawa (U.S. Pat. No. 4,015,545). A corrugated 
plastic foam core for a lightweight furniture structure having shelving 
and other applications is seen is R. Beckman, et al. (U.S. Pat. No. 
3,192,099). 
L. Maslow, et al. (U.S. Pat. No. 3,927,769) shows a ribbed construction for 
a metal shelf, though other suitable materials are also suggested. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is the principal object of the present invention to provide a 
lightweight and strong plastic shelving system. 
It is a related object of the present invention to provide a plastic 
shelving system for transport and storage of merchandise where one or more 
shelves can be added or removed without disassembly of the shelving 
system. 
It is a further related object of the present invention to provide a 
shelving system with adjustable height shelves wherein a plastic 
connection system between the post and the shelves is strong enough to 
support heavy loads. 
It is another related object of the present invention to provide a plastic 
shelving system with a unique shelf configuration to achieve high 
strength. 
In accordance with the objects of the invention, a shelving system includes 
a plurality of horizontal shelves connected and locked to upright support 
posts, which shelves carry merchandise on the shelves. Each of the shelves 
is of generally rectangular plan view, each of the four corners notched 
for receipt of a pair of corner segments which mate to each other. The 
corner segments fit around the posts and the shelves are hung or suspended 
on the corner segments in a cantilever support. A shelf is insertable or 
removeable from between two existing shelves and secured to the posts 
without moving an existing shelf. 
The posts include spaced apart slots which receive like ledges formed on 
the corner segments. The corner segments are each of generally triangular 
plan view to fit together in a male-female connection of square 
configuration having an aperture therethrough, in which aperture the post 
fits. 
The shelf is, like the remainder of the shelving system, constructed of 
high strength, high density plastic. It includes a central area of 
gradually thinning thickness from side and front and back edge surfaces. 
The bottom surface of the shelf's central area follows a particular 
curvature at any longitudinal or lateral section taken therethrough.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A shelving system 10 is seen is FIG. 1 to include a number of shelves 12 
releasably and securably connectable to upright posts 14. The shelves 12 
can be inserted or removed from between shelves already mounted to the 
posts 14 and connected to the posts 14 at any one of several positions 
along the length of the post 14, as will be described shortly. 
Each shelf 12 is releasably secured to each of the four posts 14 by a 
corner connector 16. Unlike the prior art, apertures through the shelf are 
not used to receive the post for connection purposes. By using the corner 
connectors 16, the shelves 12 can be connected to the posts 14 between 
shelves already mounted to the posts without moving the previously mounted 
shelves. 
Each corner connector 16 is comprised of a male segment 18 and a female 
segment 20. (FIG. 2). To connect the shelf to the posts, the male and 
female segments 18 and 20 are placed or mated together around one of the 
posts 14 and then one of the shelves 12 is hung or supsended onto the 
corner connector thereby formed. The male and female segments 18 and 20 
are held together about the post 14 by the connection to the shelves 12 
and to each other and the weight of merchandise on the shelves. The 
segments 18 and 20 are secured to the post 14, preventing any vertical 
movement of the connector 16 and the shelves 12 relative to the post 14. 
The shelves 12 are made of high strength, high density plastic, as are the 
posts 14 and the corner connector 16. The shelf 12 has a particular 
geometric configuration in a central area 30 on the bottom surface to give 
strength. (FIGS. 9 and 10). Each of the shelves 12 includes a top sheet 22 
and lower sheet 24. In a preferred first alternative embodiment, slots or 
louvers 26 are formed through the top and lower sheets 22 and 24, for the 
purpose of allowing air to circulate around the merchandise. (FIGS. 11, 12 
and 13). For food merchandise this is critical to avoid heat buildup and 
the likelihood of spoilage. A second alternative embodiment is embossed 
with raised ribs 27 for the same reason. (FIGS. 14-16). The ribs 27 are 
formed in the top sheet 23 extending laterally across the shelf 13. A 
bottom sheet 25 is spaced apart a set distance from the top sheet 23 as in 
the preferred embodiment of the shelf 12. A central area 31 corresponds to 
the central area 30 in shape and curvature. 
The lower sheets 22 and 24 are formed in an upwardly concave configuration 
so that the central areas 30 and 31 have less thickness than an outer flat 
area 28. The shelf is thinnest at the center. In any longitudinal or 
lateral section through the central areas, the bottom surface of the lower 
sheets follow the curvature of a portion of an ellipse. The central areas 
may be described as concave ellipsoid in shape. In a cartesian coordinate 
system with the origin at the center of the ellipse, the major axis on the 
x axis and the minor axis on the y axis, the equation for the bottom 
surface of the central area is of the form: 
##EQU1## 
where "a" is half the major axis and "b" is half the minor axis. Because 
of the geometric relationship described, the central area 30 of FIG. 9, at 
a lateral cross section (FIGS. 12 and 15) and at a longitudinal cross 
section (FIGS. 3, 10 and 16), follows a portion of the curve of the same 
ellipse. 
The shelves 12 are very strong as a result of the concave elliptical shape 
of the central areas 30 and 31. (FIGS. 10, 12, 13, 15 and 16). A 
twenty-one by forty-eight inch shelf is capable of supporting a six 
hundred pound load. 
Returning now to the embodiment of FIGS. 1 through 10, each of the shelves 
12 includes a raised peripheral lip 32 extending around the outer edge. 
The generally rectangular shelf 12 is approximately one inch thick at the 
outer periphery thereof, a front edge surface 34 and rear edge surface 36 
extend parallel to each other while the side of each shelf has parallel 
side edge surfaces 38. A corner surface 40 of the shelf 12 forms the 
surface of a corner notch 42. The corner surface extends through a right 
angle, the corner surface perpendicularly intersecting one of the side 
surfaces 38 and either the rear surface 36 or the front surface 34, as 
seen in FIG. 2. 
The corner notch 42 is shaped and dimensioned so as to mate with the corner 
connector 16. (FIG. 1). Once the corner notch 42 is mated with the corner 
connector 16 and the shelf 12 hung on the connector 16, the shelf has a 
rectangular configuration. 
Each of the posts 14 (FIGS. 4 and 8) is of elongated tubular construction. 
Each of the posts is preferably of an hexagonal cross section. Parallel 
opposed surfaces 46 of each of the posts have locator slots 48 formed or 
otherwise machined therein. The slots are horizontal, each pair of slots 
lying in a plane perpendicular to a longitudinal axis of the post. The 
locator slots 48 are used to select the height at which each of the 
shelves 12 is connected to the posts 14. Mating the corner connector 16 
around the post 14 and hanging the shelf 12 on the connector 16 allows the 
weight of the shelving system 10 to rest on steps 50 of the posts adjacent 
to the locator slots 48. The slots receive ledges 76 of the segments 18 
and 20, the ledges resting on the steps 50, supporting the shelves and 
locking the shelves in position against vertical movement. 
The corner notch 42 permits the shelf 12 to be inserted between a pair of 
shelves 12 already mounted to the posts 14. Corner connectors 16 are 
previously secured about the posts 14 and the inserted shelf 12 is hung 
thereon. Similarly, a shelf can be removed without removing the shelf 
above the shelf that is to be removed. Because all the prior art shelving 
includes apertures through the shelf through which the posts fit, a shelf 
can not be inserted or removed without removing other shelves. This is 
time consuming because the shelves to be moved must be unloaded and 
several release and reconnect operations must be done. 
The shelf 12 at the corner notch 42 includes a downwardly projecting 
continuous tooth 56 extending around the corner notch 42 and defining the 
corner surface 40. (FIG. 2). The tooth includes a crown 60 and is spaced 
apart from a vertical surface 62 of the shelf by an upwardly open 
continuous channel 58. 
Each of the segments 18 and 20 is of generally triangular plan view and 
includes an inner surface 64, a mating surface 66 and an outer surface 68. 
In the preferred embodiment the male and female segments 18 and 20 are 
substantially identical. The male segment includes a tab 52 which projects 
into an indent 54 of the female segment 20. The inner surface 64 fits 
flush against the vertical surface 62 of the shelf 12. The mating surfaces 
66 fit flush against each other when the segments 18 and 20 are placed 
together to form the corner connector 16. The outer surface 68 defines the 
exterior of the shelving system 10 and is contiguous with one of the rear 
or front surfaces 34 and 36 and a side surface 38 when the shelving system 
10 is assembled. 
Each segment 18 and 20 also includes an inwardly projecting tooth 70 
extending along the respective inner surfaces 64 of the male and female 
segments 18 and 20. The tooth 70 fits into the channel 58 of the shelf 12. 
An upwardly open channel 72 of each of the segments extends parallel to 
the tooth 70 between the outer surface 68 and mating surface 66 of each 
segment and receives the tooth 56 of the shelf 12. 
Each of the segments 18 and 20 includes an inset opening 74 defining three 
sides of the hexagonal shape of the post 14. At surfaces of the inset 
opening corresponding to the opposed surfaces 46 of the posts 14, a ledge 
76 is integrally formed. Placing the segments 18 and 20 together involves 
insertion of the ledges 76 into corresponding locator slots 48 of the post 
14. The tab of the male segment 18 fits into the indent of the female 
segment 20 to form the corner connector 16. The tooth 56 of the shelf 12 
fits into the channel 72 of the corner connector 16 and the tooth 70 of 
the corner connector 16 fits into the channel 58 of the shelf. 
The shelving system 10 thus formed is seen to assembly easily. The fit 
between the male and female segments 18 and 20 is tight enough that the 
corner connector 16 is held in position about the post 14 at the chosen 
slots 48. Similarly, the fit between the ledges 76 and slots 48 is tight, 
aiding in holding the corner connector 16 in place in supporting the shelf 
12 when it is hung on the connector 16. The shelf 12 is easily inserted 
between the posts 14 and dropped onto the corner connector. The corner 
notch 42 draws the male and female segments 18 and 20 together to more 
tightly grasp the post 14. The ledges 76 are thereby held in the slots 48. 
Although the invention has been described with a certain degree of 
particularity, the invention is most readily seen in the appended claims 
and their equivalents.