CA1302956C - Adjustable rack of shelves - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An all plastic shelf is part of a shelving system and is provided for uses where metal shelves might rust or corrode, especially if attacked by hostile chemicals. The underside of the plastic shelf has a channel formed around the periphery thereof. A welded metal frame fits into the channel, with either the width of the frame or a cover plate substantially covering the channel in order to prevent an entry of foreign matter therein. Sockets are formed in the corners of the frame to receive corner posts for supporting the shelf. These sockets fit into corner sockets which are molded into the metal frame.

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Description

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2 This invention relates to racks of adjustable 3 shelves and, more particularly, to improved 4 shelving which meets special environmental needs where metals may rust, corrode, or the like, to 6 spoil food or otherwise pose a health hazard.
7 Adjustable shelving systems (collectively and 8 generically called "shelves~ herein) are known in 9 the art. Such shelves have many advantages in that, among other things, they enable a 11 maximization of the use of costly storage space.
12 Such shelving is also easily adapted to accommodate 13 and support a great variety of product sizes, thus 14 enabling a great flexibility as storage reguirements change.
16 An adjustable shelving system has been 17 described in U.S. Patent Nos. 3,424,111 and 18 3,523,508. This system makes use of shelf members, 19 circular corner shelf supports, circular corner posts with graduated recesses and two-piece, semi-21 circular post supports for holding the shelf 22 support and corner post in place. More 23 particularly, the shelf supports are preferably 24 metal and are comprised of two separate pieces which are wrapped around the corner post and 26 snapped into place. Thus, in order to adjust the ~$' 13~295ti 1 height of the shelf, the shelf supports must be 2 detached from the shelf and moved. If one section 3 of the shelf support is lost or broken, the 4 shelving is useless until another shelf support is obtained.
6 The shelves may be used to store many 7 different things including food, medicine, and 8 other things which are impacted by or have an 9 impact upon both the environment and health. ~hen human life or health are involved, it becomes 11 especially important to prevent contamination.
12 Shelves must be completely cleanable, must not 13 deteriorate, and must not create health hazards.
14 For example, shelves must not rust or corrode which could produce toxic chemical reactions. Moreover, 16 the shelves should not be attacked by chemical 17 substances which may be spilled on them.
18 Stainless steel is a material which fits most 19 of the needs for shelves of the described type.
Such shelves are strong enough and rigid enough to 21 meet the various types of storage requirements for 22 which adjustable shelving is often used. However, 23 stainless steel is very expensive, as compared to 24 other materials, and sometimes there could be other practical reasons for not selecting it. Galvanized 26 steel resists rust, hut it is attacked by galvanic 27 currents which may strip away the zinc coating.

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1 Plastic coated iron is also satisfactory under many 2 conditions. However, any coated material 3 (galvani2ed, painted, dipped, etc.) is subject to 4 nicks, scratches, and the like, which exposes the underlying base metal to attack, rust, corrosion, 6 or the like.
7 Although shelves made from plastic are 8 lightweight, relatively easy to clean and resistant 9 to rust and attack by chemical substances, such shelves are not as strong as metal shelving and, 11 therefore, often not strong enough to meet 12 different storage requirements. Such plastic 13 shelves are not individually strong enough to 14 support heavy loads and when assembled into a unit of several shelves do not provide a rigid and 16 stable system.
17 An adjustable rack of shelves is provided 18 comprising a plurality of shelves having corners 19 with corner post receiving sockets. At least two corner posts are provided, each corner post having 21 a plurality of capture means formed on the post to 22 secure the shelves in place. Keeper means are 23 provided to fit over the corner posts for mating 24 with the capture means, the keeper means being adapted to fit into the corner post receiving 26 sockets of the shelves so that when the keeper 27 means mate with the capture means, tAe shelf will 13~
1 be secured in place on the corner posts. Each of 2 the shelves is made of molded or formed plastic 3 with an underside channel extending peripherally 4 along the edge of the shelf. Metal reinforcing members are shaped to fit into the channels. A
6 plurality of metal sockets for receiving the keeper 7 means are secured to the reinforcing members and 8 adapted to fit into the corner post receiving g sockets.
The above mentioned and other features of this 11 invention and the manner of obtaining them will 12 become more apparent and the invention itself will 13 be best understood by reference to the following 14 description of an embodiment of the invention taken in conjunction with the accompanying drawings, in 16 which:
17 Fig. 1 is a perspective view of an adjustable 18 rack of shelves having a shelf and post 19 combination:
Fig. lA is a perspective view showing, in 21 greater detail, a corner portion of the adjustable 22 rack of shelves shown in Fig. l;
23 Fig. 2 is a perspective view of a shelf post 24 with notches spaced at regular intervals, such as 1-inch to 1-1/2 inches;
26 Fig. 3 is a perspective view of a plastic keep 27 used by the invention to lock a shelf in place;

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1 Fig. 4 is a perspective view (partly broken 2 away) of an embodiment showing a plastic shelf;
3 Fig. 5 is a cross section of a first 4 embodiment taken along line 5-5 of Fig. 4;
Fig. 6 is a cross section of the first 6 embodiment taken along line 6-6 of Fig. 4;
7 Fig. 7 is a cross section of a second 8 embodiment taken along line 5-5 of Fig. 4;
9 Fig. 8 is a cross section of the second embodiment taken along line 6-6 of Fig. 4;
ll Fig. 9 is a cross sectional view of a third 12 embodiment taken along line 5-5 of Fig. 4; and 13 Fig. 10 is a cross section of the shelf 14 showing a corner post in place, within a corner socket on the shelf.
16 As shown in Fig. 1, a rack of shelves 20, 17 constructed in accordance with the teachings of the 18 above-identified prior applications, comprises at 19 least one flat shelf 22 having four corner sockets 24, corner posts 26 with a graduated, plurality of 21 recurring dimples, recesses, or notches 28 and 22 keepers 30 for maintaining the shelf in a selected 23 position on each post 26. To expedite assembly, a 24 pyramidal cap 27 (Fig. lA) may be used on the top of each post 26. This cap seals the top and 26 readily guides the socket and keeper parts which 27 fit over the post into place, without catching. On :~u~
1 the bottom of each post is a threaded metal or 2 plastic insert (not shown) which seals the bottom 3 and provides a thread for adjusting a leveling bolt 4 to fit non-level floors. Heretofore, shelf 22 has been constructed of a mesh of metal wires or rods 6 32 welded together or otherwise secured in any 7 suitable manner to a shelf frame 34.
8 As shown in greater detail in Fig. lA, the 9 corner sockets 24 are welded to the frame 34, for receiving the vertical posts. Each of these 11 sockets has an internal projection with a somewhat 12 truncated pyramidal shape. The bottom end of the 13 socket is tapered outwardly with respect to the top 14 end in order to guide the post 26 into position and to form an effective wedge holding action in 16 cooperation with the keeper 30.
17 As shown in Fig. 2, the post preferably having 18 a generally rectangular cross section is provided 19 with a plurality o~ notches 28 spaced at regular intervals of about one to one and one-half inches 21 along the length of at least one edge of the posts 22 26. These notches receive and accommodate detents 23 40 located on the interior contour of the keeper.
24 The construction details of one exemplary 2S keeper 30 appear in Fig. 3. As there shown, the 26 keeper comprises a one-piece, truncated, generally 27 pyraMid-shaped sleeve which can be placed over the 13~29~6 1 shelf post 26. Keeper 30 has a solid top edge 12, 2 except for a relatively small slot 14 which enables 3 the keeper to spring apart and enlarge its internal 4 cross section as the detents 40 on each internal edge pass into and out of the notches 28 on the 6 post 26. Because the top edge 12 is continuous, 7 except for slot 14, debris will not build up in 8 slots 16-20 which open downwardly through the 9 bottom edges of the sides 22-26 respectively.
These slots also help the keeper to flex as the 11 socket presses downwardly. A suitable material of 12 construction for the keeper is nylon.
13 This invention also makes it possible to 14 economically add any number of supplemental units with only two posts (a savings of two posts per 16 shelf unit). This is accomplished by a use of two 17 inexpensive clips, per shelf, to extend additional 18 units in line or perpendicular to the last unit.
19 This inventive adjustable shelving rack is not limited to use in a stationary installation. It 21 has the flexibility to be made into a mobile unit 22 by inserting round or square stemmed casters, in 23 lieu of threaded leveling inserts, into the bottom 24 of the post.
The shelf 22 (Fig. 1) is inherently directed 26 to metal since the strength of metal is required 27 for many storage applications. These shelves may i3tJ2:~3S~6 1 be steam cleaned, if made of stainless steel.
2 However, if the metal is a coated material 3 (galvanize, paint, plastic, etc.), they are subject 4 to scratching, chipping, or the like. This leads to an exposure of the base metal with all of the 6 possibilities of rust, corrosion, contamination, 7 and deterioration.
8 To overcome these and similar problems, the 9 invention uses a plastic shelf 50 (Fig. 4) having the geometry of the shelf 22, in Fig. 1, so that 11 the two shelves 50, 22 may be used interchange-12 ably. Preferably, shelf 50 is molded from a high 13 density polyethylene material or structural foam, 14 with an upper surface which may be either a solid and unbroken sheet or a sheet which has openings 52 16 formed therein. Convenience of the user i5 a 17 primary consideration of the design of this 18 surface. If convenience is not material, the 19 consideration is one of weight and strength.
In one preferred embodiment, the invention 21 used Dow HDPE Resin 08054N, which has FDA approval 13~Z~6 1 for food contact. The manufacturer describes this 2 resin as follows:
E~G::S~SI Asrx 1,2 ~I-S ~;3~ QQ
G~ner~l: M~lt Index (l90-C/2160 g~) 8.0 q~/10 min 8.0 q~/10 min D-1238 Molt Flow Ratio (~lo/~2) 6.a 6.8 D-12~8 Ann~ d D~nsity .964 g~/~l .964 gm/~l D-792 Apparent Dynamic Vis~o~ity ~ 230 C and 300 sec 1 3100 p 310 Pl-~ D-3835 e 230-C ~nd looo s-c~1 l9oo p ~go P~-- D-3a35 e 230-C and 5000 ~-c~ 800 p 80 Pa~- D-3835 ~c~anical: T~n~ Strenqth at Yield3 38~0 psi 30 HPa D-638 Ten~ Str~ngt~ ~t Break3 2700 psi 19 MPa D-638 Elonqation 1300 ~ 130~ % D-638 S~ant Modulus, e 2% Elongation 165,000 psi 1140 MPa D-790 Flexu~Al ~odulus ~30,000 psi 1280 MPa D-790 NotchQd ~zod Impact, e -50-C ,go ft-lb/in 48 J/M D-256 TensilR I~pact 47 ft-ib/in2 170 XJ/~2 D-1822 T~r~al: Vleat So~teninq Point 263 F 128 C D-1525 Brittlen~s~ T~mperat~rQ <-105 F ~-76 C D-746 1~ypic~1 valu~s, not to be construed as ~peci~ications.
2All ta~t~ p~r~or~d on ~o~pr~ion ~old-d sa~plh~.
3Cro~shs~d ~p~-d, 2.0 inch-~/minut-.

3 This narrow molecular weight distribution 4 homopolymer offers an excellent impact strength and stiffness with good stress crack resistance. Dow 6 HDPE 08054N has good processability over a wide 7 range of molding conditions.
8 In another embodiment, structural molded foam 9 is used to form the shelves. An inert gas, such as nitrogen, is mixed with resin during the melting 11 process used to mold the shelf. As the resin 12 liquefies, the gas expands and as the resin cools, 13 the gas contracts causing cellular structures to 14 form in the molded shelf. This results in a molded ~3~Z95q~
1 shelf with a solid skin or outer surface and a 2 cellular core, which yields a structure having a 3 high strength to weight ratio.
4 As shown in Fig. 4, a channel 54 extends around the underside of a perimeter of the shelf to 6 receive a reinforcing metal frame 56. This frame 7 is substantially the same as frame 34 of Fig. lA, 8 which includes side rails 34 welded to corner 9 socket 24. The plastic shelf 50 has a relatively large socket 58 formed therein to receive and 11 snugly embrace the metal socket 24.
12 In another embodiment (not shown), individual 13 metal bars or members are used to reinforce plastic 14 shelf 50. The individual members are received by channel 54, but are not connected to one another.
16 In this embodiment, individual metal sockets 24 are 17 fitted within sockets 58 of plastic shelf 50.
18 The underside of the shelf 50 is molded with 19 vertical, or orthogonally oriented fins 60, which can be tapered in shape, to impart added strength 21 to the shelf to support objects resting on the 22 shelf. In one embodiment these fins were 23 alternated with shorter fins 62 since that way an 24 adequate strength is provided with a lighter weight and with a resulting savings of material.
26 The metal frame 56 may have any convenient 27 configuration. In one embodiment (Fig. 9), the ~3~2956 1 frame 56 is formed from closed box side rails 80 2 which occupy the entire channel 54 to preclude 3 entry of foreign matter. The shape of side rails 4 80 can be either rectangular or square. This embodiment is desired when a maximum strength is 6 necessary or desirable.
7 In another embodiment (Figs. 5, 6), each of 8 the side rails 56 has a generally C-shaped cross 9 section. Preferably, the lower or transverse flange 64 of said C-shape is wide enough to seal 11 off the entire entrance to channel 54, thereby 12 barring entry of foreign matter into the channel 13 54. The vertical flange 66 may have any suitable 14 height that may be necessary to provide the desired mechanical strength. The width of the 16 upper or transverse flange 68 is also determined by 17 the mechanical strength required for the total 18 structure.
19 In the embodiment of Figs. 7, 8, it is assumed that the mechanical strength requirements are such 21 that the upper or transverse flange 70 should be 22 wider than flange 68, and that any material savings 23 may be realized by providing a narrow lower or 24 transverse flange 72. However, such a narrow flange 72 leaves an open space which, if 26 uncorrected, would provide a cavity entrance that ~3~;~9~6 l might lead to contamination, shelter for insects, 2 or the like.
3 To preclude such contamination problems, the 4 invention provides cover plates 74 for closing the entrance to channel 54 that is formed in the 6 plastic. The top of plate 74 has a longitudinal 7 strip 76 extending along the length thereof to hook 8 over lower flange 72 of the side rail 54. The 9 cover plates 74 are secured in place by screws 78 which periodically join the plates 74 to the 11 plastic shelf, or any other suitable fastener 12 means, such as pop-in rivets. In some 13 applications, it may be desirable to eliminate the 14 need for such fasteners and adapt the cover plate 74 and shelf 50 so that the cover plate 74 will 16 snap into place in channel 54. The cover plates 17 are preferably made of plastic.
18 In other embodiments (not shown), side rails 19 56 can be H-shaped, I-shaped, U-shaped, S-shaped, T-shaped or L-shaped.
21 In each of the embodiments, one or more screws 22 81 may be added to hold the side rail 56 in place.
23 Channels 54 can be molded to provide internal ribs 24 or detents to engage the metal reinforcing so that the metal reinforcing members or frame snap into 26 place without the need for screws 81.

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lThe principle of the invention may be expanded 2 by adding any suitable number of support members or 3 rails intermediate the ends of the metal 4 reinforcing members disposed in channels 54 or of the metal frame 56, as indicated by dot-dashed 6 lines 82, 84 (Fig. 4). The support members may be 7 oriented in any suitable manner (diagonally across 8 the shelf or straight across the width or length of 9 the shelf). For example, these added support members may be welded or otherwise attached to the 11 side rails 56 before being inserted into the molded 12 plastic shelf and fitted into channels similar to 13 54 which are molded into the plastic shelves. The 14 support members may also be molded into the shelf by means of insert molding.
16To further preserve and protect the metal from 17 the environment, and the environment from the 18metal, a sealant 86 (Figs. 5, 8, 9) may be added to 19 completely encase the metal frame 56. This sealant may be a plastisol or an elastomer which is 21 approved for use in contact with food which may be 22 consumed by a human. It may be applied as a hot 23 melt or sprayed on; or, it may be applied in any 24 other suitable manner.
25Fig. 10 explains the installation of the 26 shelves and the operation of the parts~ First, the 27 keeper 30 is slipped over the corner post 26 and 1 slid along the post until detent 40 fits into a 2 selected notch 28. Then the plastic socket 58 on 3 the shelf is fitted over the corner post, with the 4 metal socket 24 in place inside socket 58. The metal socket 24 is welded at 88 to the side rails 6 56. At this time the plastic socket 58 molded into 7 the plastic shelf surrounds and practically covers 8 both the keeper 30 and the metal socket 24. Next, 9 a cap 90 is slipped over the post 26 and slid down into abutment with the top of plastic socket 58, in 11 order to close any crack between post 26 and 12 plastic socket 58.
13 The advantages of the invention are that it 14 provides a shelving system that is lightweight, resistant to rust and attack by chemical substances 16 and comparable in strength to steel shelving.
17 Moreover, if the spilled material should run off 18 the edge of the shelf, the metal framP 56 is buried 19 deeply enough within the lower side of the plastic to keep it from being attacked. In fact, a lip 51 21 can be provided around the perimeter of the shelf 22 to prevent spilled material from running over the 23 edge of the shelf. If the environment is 24 espPcially hazardous, the cover plate, and perhaps sealant, further protects the metal frame.
~6 Those who are skilled in the art will readily 27 perceive how to modify the invention. Therefore, 13~Z9S6 1 the appended claims are to be construed to cover 2 all equivalent structures which fall within the 3 true scope and spirit of the invention.

Claims (18)

1. A shelving system comprising a plurality of shelves having corners with corner post receiving sockets formed therein; at least two corner posts each having a plurality of capture means formed thereon; keeper means for mating with said capture means, said keeper means fitting over said corner posts and into said socket for securing said shelf to said posts; characterized in that each of said shelves is made of molded or formed plastic having an underside channel extending peripherally along the edge of each shelf; metal reinforcing members shaped to fit into said channel; and a plurality of metal sockets for receiving said keeper means, said metal sockets secured to said reinforcing members and adapted to fit into said corner post receiving sockets.

2. The shelf of claim 1 wherein said metal reinforcing members comprise a metal frame formed from a plurality of side rails joined at their ends to said metal sockets, said rails shaped and dimensioned to fit into said channels.

3. The shelf of claim 2 wherein said side rail includes a transverse flange which occupies almost all of the width of said channel thus tending to seal the channel against entry of foreign matter.

4. The shelf of claim 3 wherein said side rail has a somewhat C-shaped cross section and said transverse flange is the lower portion of said C-shape.

5. The shelf of claim 2 wherein said side rail has a somewhat C-shaped cross-section, the bottom flange of said C-shaped cross-section being less than the full width of said channel, a cover plate extending along a width and length of said channel to cover and close said channel, said cover plate having a thin strip of plastic integrally formed thereon to slip over and thus attach to said flange, and fastener means for holding said cover plate in place.

6. The shelf of claim 2 wherein said side rail has a box shaped cross-section which substantially fills the channel.

7. The shelf of claim 2 and a sealant covering said frame and extending across said peripheral channel for sealing said metal frame in said channel, whereby chemicals spilled on said shelf do not attack said frame.

8. The shelf of claim 2 and a cap surrounding and in close abutment with said molded plastic socket for covering and closing any crack between said sockets and a corner post.

9. The shelf of claim l wherein at least one cross brace extends across the underside of the shelf intermediate the ends of the metal reinforcing members, and a channel is formed in said plastic shelf for said cross brace to fit into.

10. The shelf of claim l wherein said shelf integrally has a plurality of vertical fins dependent from an underside of said shelf to add vertical supporting strength to said shelf.

11. The shelf of claim 10 and openings through said shelf between said vertical fins.

12. The shelf of claim 1 wherein said shelf has a solid upper surface.

13. The shelf of claim 1 wherein said shelf has openings formed therein.

14. The shelf of claim 12 wherein said shelf has a raised upwardly extending lip around the upper perimeter of the shelf.

15. A shelving system comprising shelves having corners with corner post receiving sockets formed therein; corner posts with a plurality of capture means formed periodically along the length thereof for engaging and securing said shelf in place at a desired position on said posts; keeper means for mating with said capture means and adapted to fit around said corner posts and to engage said shelves to secure the shelves in place on said posts at selected ones of said capture means; each of said shelves being made of molded or formed plastic having an underside channel extending peripherally along the edge of said shelf and a metal frame having side rails fitting into said channel and having sockets attached to said side rails and fitting into said corner post receiving sockets, the sockets of said metal frame being shaped and dimensioned to receive and hold said keepers.

16. A shelf for a rack of shelves which are supported by at least two corner posts, each of said corner posts provided with a plurality of capture means formed periodically along the length thereof for engaging and securing said shelf in place at a desired position on said posts; a plurality of keeper means for mating with said capture means and adapted to fit around said corner posts to secure said shelves in place on said posts; a molded or formed all-plastic shelf having at least peripheral channels formed therein and on the underside thereon, said channels opening to the exterior of the shelf; plastic post receiving sockets molded or formed into at least two corners of said shelf at intersections of said peripheral channels; metal reinforcing members shaped and dimensioned to fit into said channels, said members comprising a metal frame formed from a plurality of side rails each of which includes a transverse flange disposed along the bottom of said rail and positioned to extend across the opening in said channel; a plurality of metal sockets secured to said reinforcing members and disposed in said corner post receiving sockets, said metal sockets adapted to receive and hold said keepers.

17. The shelf of claim 16 wherein said side rails have a somewhat c-shaped cross section and said transverse flange is the lower portion of said c-shape.

18. The shelf of claim 16 wherein said side rails have a somewhat c-shaped cross-section, the bottom flange of said c-shaped cross-section being less than the width of said opening; a cover plate extending along a width and length of said channel to cover and close said channel; said cover plate having a thin strip of plastic integrally formed thereon to slip over and thus attach to said flange, and fastener means for holding said cover plate in place.