Modular and stackable tray assembly

Abstract

A system of open top trays of variable heights arranged to be stacked in any arrangement and with the trays in a stacked position defining a common interface datum plane between adjacent trays and releasably locked together. Each tray includes a bottom, longitudinal and transverse perimeter walls, with the perimeter walls being inclined outwardly and terminating in an upper rim, with the perimeter of each tray having the same dimensions regardless of its height. A latch handle is rotatably mounted on each transverse wall at a distance d1 below the datum plane. A latch hook protrudes outwardly from each transverse wall at a distance d2 above the datum plane with the latch handle having a locking tab for engaging an associated latch hook of an above positioned tray to releasably lock the trays together.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an assembly of individual trays of different heights which can be releasably locked together and carried as a single unit.

2. Description of the Prior Art

Boxes, and particularly compartmentalized boxes, for storing craft, fishing hardware and other small items (e.g., beads, lures, screw, etc.) are generally configured as single units with lids. Each unit is generally carried separately or stacked in an unsecured arrangement. Picking up and transporting a pile of such boxes can easily cause an unexpected separation of the piled boxes spilling the contents thereof.

Stackable storage containers which can be releasably locked together are known as illustrated, for example, in U.S. Pat. No. 3,339,725 (“'725 patent”); U.S. Pat. No. 4,619,363 (“'363 patent”); and U.S. Pat. No. 6,273,258 (“'258 patent”).

The '725 patent employs a flat sheet (1) of cardboard or the like with the central section extending over the top container and the end sections extending along the sides of the single or stacked container(s) and secured to the beaded rim(s) surrounding the openings(s) of the lower container(s). The sheet (1), which holds the containers together, constitutes an extra component and does not provide a particularly reliable/reusable locking system.

The '363 patent discloses a storage unit in which two trays of different heights and apparently vertically aligned side walls may be stacked and carried as a unit. A separate connecting element (13) is releasably secured between the sides of each pair of stacked trays. While the connecting elements would apparently provide a secure locking arrangement between the several trays, they would be cumbersome to use. The patent refers to the possible use of a hinged connecting element, as an alternative. However, no specifics are given as to its construction.

The '258 patent discloses a stackable container system for storing foodstuffs in which identical containers are secured together by flexible flaps (18). Such a flexible flap arrangement is not particularly robust. Also, absent the presence of the lid 22, there is no convenient handle with which to carry the stacked containers.

There is a need for a economical and stackable tray assembly with a robust locking mechanism, particularly for a stackable tray system in which the trays have different heights with optional dividers to form individual compartments within the trays. For economic reasons trays and other containers for storing small items are often injection molded of a plastic material such as polypropylene, polyethylene or copolymers. A split two-part mold can be employed to form straight peripheral or side walls in such trays. While the use of a single non-split mold will result in a simpler and less expensive molding process, the peripheral walls must be outwardly inclined (i.e., draft angle) in order to remove the molded tray from the mold. The releasable locking arrangement of my invention accommodates stacked trays of different heights and the use of a single mold for each tray height.

SUMMARY OF THE INVENTION

A system for open top trays of variable heights arranged to be stacked together in any arrangement, in accordance with the present invention, comprises a group of trays with each tray having a bottom and longitudinal and perimeter walls which terminate in an upper edge or rim defining an opening through which articles may be placed in and removed from the tray. Preferably a plurality of dividers are mounted in the tray to form individual compartments. The peripheral walls have an inwardly stepped or undercut section joined to the bottom which undercut section nests on the rim of the lower tray in a complementary manner to substantially align the peripheral walls of the nested trays with the rim of each tray having the same dimensions regardless of the tray height. The trays in a stacked position define a common interface datum plane coincident with the rim of the lower tray. A latch handle is rotatably mounted on the exterior of each transverse perimeter wall about a rotational axis located at a distance d₁ below the datum plane and a latch hook protrudes outwardly from each transverse wall at a distance d₂ above the datum plane. The latch handle includes a locking tab arranged to engage the latch hook of an above positioned tray (or lid) when the latch handle is rotated to a closed position.

Preferably each latch handle is rotatably mounted on an axle molded integrally with the transverse walls and spaced outwardly from a recessed central section thereof Alternatively the latch handles may be provided stub axles positioned in an axle receiving openings in the transverse walls adjacent a recessed central section thereof.

Preferably the rotational axis of the latch handles and the latch hooks are separated by distances d₃ and d₄, respectively, regardless of the height of the tray. The underside of the latch handle (in the locked position) has a generally semicylindrical shape to provide a user friendly handle portion for lifting and transporting stacked trays. Preferably the trays are provided with integrally molded or removable dividers to form compartments within the individual trays.

In addition the assembly includes a lid with a top wall, longitudinal and transverse side walls with a latch hook extending outwardly from each transverse wall and above the datum plane by the distance d₂ for engagement by the locking tab of an associated latch handle on the underlying tray. The lid further includes a pivotal handle in the center section of the lid top wall to accommodate the hand of a user desiring to lift and transport the stacked assembly.

The modular and stackable tray assembly of the present invention may best be understood in reference to the following description taken in conjunction with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a stackable tray assembly including a cover or lid in the stacked and locked position in accordance with the present invention.

FIG. 2 is a side elevational view of the assembled trays of FIG. 1.

FIG. 3 is a front elevational view of the assembled trays of FIG. 1.

FIG. 4 is an exploded disassembled perspective view of the trays of FIG. 1.

FIGS. 5 and 6 are perspective views of the lower and assembled lower and intermediate trays shown in FIG. 1, respectively.

FIG. 7 is a cross sectional view, partially broken away, taken along lines 7-7, of FIG. 2, showing the releasable locking arrangement for the individual trays with the dividers illustrated in FIG. 4 not shown for clarity.

FIG. 8 is an enlarged view of the releasable locking arrangement between two of the trays of FIG. 7 illustrating various dimensions.

FIG. 9 is an enlarged view of the releasable locking arrangement between the cover or lid and one of the trays of FIG. 7 illustrating various dimensions.

FIGS. 10 and 11 are perspective views of the front and rear sides of the latch handle, respectively.

FIGS. 12 and 13 are top and bottom plan views of the cover or lid, respectively.

FIG. 14 is a perspective view of the handle for the cover.

FIG. 15 is a perspective view of an alternative latch handle.

FIG. 16 is a partial perspective view of a transverse peripheral wall of a tray showing an opening therein for receiving the stub axles of the alternative latch handle.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1-5 a tray system or assembly designated generally at 10 of the present invention includes a plurality of open top trays with a bottom tray 12, an intermediate tray 14, an uppermost tray 16 and a cover or lid 18.

The trays are injection molded, preferably with a one piece mold, of a suitable rigid thermoplastic material such as polypropylene, polyethylene or a copolymer. Preferably, the trays, i.e., at least two, have different heights, h. As an example, a set of four trays may have heights of 4″, 3″, 2″ and 1¼″ and have suitable lengths and widths such as 16″ and 8″, respectively. It is to be understood that the specific dimensions given are by way of example only.

As is illustrated more particularly in FIGS. 5 and 7, each tray includes a bottom wall 20, longitudinal peripheral walls 22, and transverse peripheral walls 24 (collectively “peripheral walls”) with the peripheral walls being inclined outwardly to the vertical (at an angle designated as θ in FIG. 3) to accommodate removal from the mold. The peripheral walls terminate in a an upper edge or rim 25 through which articles may be placed in and removed from the open trays. The angle θ of the inclination may be in the range of 0.5° to 2° with the angle dependent upon the height h of the tray so that the rim of the trays have substantially the same dimensions for nesting purposes as will be explained. The peripheral walls are joined to the bottom via an inwardly stepped or undercut section 23 (FIG. 7) which mates with the rim of the lower tray to align the peripheral walls and maintain the trays in a nested arrangement. As is illustrated in FIG. 8 a horizontally oriented shelf 23a of the undercut section rests on the rim 25 of the lower tray.

The longitudinal and transverse peripheral walls are joined at a radiused corner sections 26 (FIG. 5) with the center sections 22a of the longitudinal walls recessed slightly, as illustrated, for decorative purposes. A central section 24a of the transverse walls is also recessed with axle 28 integrally molded into the side sections 24b and spaced outwardly from the central section (FIG. 1) to accommodate an axle receiving groove 30a in a latch handle 30 (FIG. 14) rotatably mounted on the axle as will be explained in more detail (the side sections 24b extending perpendicularly outwardly from the central section 24a). The center of the axle is supported via a stub support member 28a which extends outwardly from the recessed center portion 24a. See FIG. 8. The peripheral walls include circumscribing outwardly protruding ribs 31, adjacent the rim, for decorative purposes. See FIG. 5.

A protruding latch hook member 32 (extending upwardly from two spaced horizontal ribs 32a) is also integrally molded in the bottom of the center section 24a of each transverse peripheral wall for receiving a locking tab 30b on the latch handle when in its closed position to lock the several trays together. See FIGS. 1, 8 and 9. The latch handle is formed with a tab 30c which may be rotated by a user's finger to engage or disengage the locking tab from the latch hook 32 to lock or unlock the trays. The underside 30d of the bottom of the latch handle is semicircular in shape and serves as a handle for lifting one or a stack of trays. The center section of the bottom of the latch handle is notched at 30e to accommodate the stub support member 28a. See FIGS. 10 and 11.

As discussed earlier the trays, in a stacked position, with the undercut shelf 23 a of the upper shelf resting on the rim 25 of the lower shelf, define a datum plane coincident with the lower tray rim as is illustrated in FIG. 8.

The axle 28 is spaced below the datum plane by a distance d₁ with the latch hook 32 spaced above the datum plane by a distance d₂ in each tray regardless of the tray height. The distance between the center of the latch handle groove 30a and the locking tab equals d₁+d₂. Preferably the distances d₃ and d₄ between the axles 28 and latch hooks 32, respectively, on each tray, regardless of tray height, are the same so that the axles and latch hooks will be aligned vertically (although in different planes as illustrated) with the trays in a stacked position as is illustrated in FIG. 7.

Referring now to FIGS. 1, 12 and 13 the cover or lid 18 includes longitudinal and transverse perimeter walls 18a and 18b, respectively, with a center section 18c of each transverse wall being recessed for alignment with the recessed center sections 24a of the trays in the stacked position. The sections 18c are molded with protruding latch hooks 32′, aligned with the latch hooks 32, of the lower stacked trays. As is illustrated in FIG. 9 the locking tab 30b of the lower tray latch handle engages the latch hook 32′ to lock the cover to the underlying tray(s). As is illustrated in FIG. 9, the distances d₅ and d₆ represent the distances between the axles 28 and latch hooks 30b, respectively, from the recessed wall sections 28a.

The lower end of the cover perimeter sections are formed with an overcut section 18d defining a horizontally extending shelf 18e and an overhanging vertically oriented skirt 18f. The shelf 18e rests on the rim of the underlying tray and defines the datum plane for determining the distance d₂ as is best illustrated in FIG. 9. The skirt 18f fits over the outside of the rim and upper portion of the perimeter walls of the lower tray.

The upper side of the cover includes a depressed center section 18g, merged between side sections 18h via vertically oriented stub walls 18i. The stub walls have openings 18j for receiving stub axles 36a of a handle 36. See FIGS. 1 and 14. The longitudinal and peripheral sections of the cover include decorative curved sections 18k merged with the overcut section 18d.

As is best illustrated in FIG. 13 the underside of the center section of the cover is designated 18g. Strengthening ribs 18l are also included on the underside of the cover.

Referring now to FIGS. 4 and 5 divider receiving guides 38 are integrally molded to the interior surfaces of the longitudinal perimeter walls of trays 12 and 14 with removable dividers 40 mounted in some of the guides. Each guide is formed by a pair of elongated opposed generally semicylindrical sections 38a defining a narrow slot therebetween for receiving and releasably retaining a divider 40. Preferably the removable dividers are formed with semicylindrical end sections 40a which are complementary with the elongated cavities formed by the sections 38a. See FIG. 5.

One or more dividers 42 may be integrally molded with the trays as illustrated in tray 16 of FIG. 4. In addition vertically oriented spool receiving posts 42 may be integrally molded in a section of a tray. Alternatively, the posts 42 may be molded to a removable plate (not shown) for placement in a section of the tray as in FIG. 4.

The dividers may have a height, such as is illustrated in the tray 14, so that the bottom of a overlying tray will be positioned closely above the dividers to inhibit any articles from spilling from one compartment to another in the event that the locked assembly is tipped upside down.

As an alternative to the latch handle and fixed axle arrangement shown in FIGS. 1 and 9-11, the latch handle (designated 40) may be in the form shown in FIG. 15 and 16 with stub axles extending into openings 42 in the transverse wall side sections 24b′. With either arrangement the latch handle rotates about an axis of rotation located at distance d₁ below the datum plane.

While the trays and cover may be molded of any suitable plastic, they are preferably made of polypropylene. I have found that the nominal wall thickness t of 0.080″ for the trays is suitable while a somewhat greater thickness may be preferable for the skirt sections of the top since the top must carry the weight of the stacked assembly when the handle 36 is used to transport the underlying trays. It is to be noted that the semicylindrical latch handle portions 30d may be used to carry the assembled trays with or without the cover in place.

There has thus been described a novel modular and stackable tray assembly with the individual tray arranged to accommodate removable or stationary dividers to form compartments and a reliable locking system to allow a stacked tray assembly to be conveniently carried with or without a cover. Various modifications to the invention will become apparent to those skilled in the art without involving any departure from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A system of open top trays of variable heights arranged to be stacked and releasably locked together in any arrangement independent of the individual tray heights, the trays in a stacked position defining a common interface datum plane between adjacent trays, each tray comprising: a bottom and longitudinal and transverse perimeter walls terminating in an upper rim defining an opening through which articles may be placed in and removed from the tray, the perimeter walls being inclined outwardly with respect to the vertical with the rim of each tray having the same dimensions regardless of the height of the tray; an axle spaced outwardly from each transverse wall to accommodate a rotatable latch handle mounted thereon, the axle being located below the datum plane by a first predetermined distance d1; a latch hook protruding outwardly from each transverse wall and located above the datum line a second predetermined distance d2; and a latch handle rotatably mounted on each axle, the latch handle having a locking tab arranged to engage the associated latch hook of an above positioned tray when the latch handle is rotated to a closed position.

2. The system of claim 1 wherein the peripheral walls include an inwardly stepped section joined to the bottom with the stepped section providing a mating interface with the upper edge of the peripheral walls of a below positioned tray and defining the datum plane so that when the trays are in a stacked relationship the peripheral walls of each container are substantially aligned.

3. The system of claim 2 wherein the transverse walls have a recessed center section and wherein the axles and latch hooks are positioned in the center sections.

4. The system of claim 2 wherein each latch handle terminates at one end in the shape of an inverted j-hook defining a groove arranged to fit over the associated axle and terminates at the other end in a finger engaging surface with any intermediate inwardly extending locking tab, the j-hook portion defining a convenient handle for carrying one or several stacked trays.

5. The system of claim 4 wherein the longitudinal peripheral walls of the tray define a plurality of vertically oriented opposing divider receiving guides.

6. The system of claim 5 wherein each guide is formed by a pair of elongated opposed generally semicylindrical sections defining a narrow slot therebetween.

7. The system of claim 2 wherein the distance d3 between the axles and the distance d4 between the latch hooks are the same regardless of the height of the tray.

8. The system of claim 2 further including a cover having longitudinal and transverse perimeter sections with the transverse sections having a recessed center portion with a protruding latch hook on each transverse center portion section, the perimeter sections defining an overcut portion adjacent the bottom thereof with a horizontally oriented shelf arranged to engage the rim of an underlying tray, the latch hook being positioned above the shelf by the distance d2.

9. The system of claim 8 wherein the perimeter sections of the cover further define an overhanging vertically oriented skirt arranged to extend over the outside of the upper portion of the perimeter walls of an underlying tray.

10. The system of claim 9 wherein a rotatable handle is mounted on the top of the cover.

11. An assembly of compartmentalized trays of variable heights arranged to be stacked and releasably locked together, each tray comprising: a bottom and longitudinal perimeter walls and transverse perimeter walls with the perimeter walls being inclined outwardly at angle θ and terminating in an upper rim defining an opening through which articles may be placed in and removed from the tray, each transverse wall having a central section; a plurality of dividers mounted in the tray to form individual compartments; an axle positioned adjacent the upper edge and spaced from the central section of each transverse wall to accommodate a rotatable latch handle mounted thereon; a latch hook protruding outwardly from each transverse wall adjacent the bottom in vertical alignment with the axle; and a latch handle rotatably mounted on each axle, the latch handle having a locking tab arranged to engage the associated latch hook of an above positioned tray when the handle is rotated to a latched position.

12. The container assembly of claim 11 wherein θ is within the range of about 0.5° to 2°.

13. The container assembly of claim 12 wherein the peripheral walls include an inwardly stepped section joined to the bottom with the stepped section accommodating the rim of another container so that when the containers are in a stacked relationship the peripheral walls of each container are substantially aligned.

14. The container assembly of claim 13 wherein each latch handle defines a groove at one end which fits over the associated axle, a finger engaging surface at the other end and an intermediate locking tab.

15. The container assembly of claim 14 wherein each transverse perimeter wall is formed with an inwardly stepped center section with the axle extending across the center section adjacent the upper edge and an outwardly extending latch hook disposed in the center section adjacent the bottom.

16. A system of open top trays of variable height arranged to be stacked and releasably locked together in any arrangement independent of the individual tray heights, the trays in a stacked position defining a common interface datum plane between adjacent trays, each tray comprising: a bottom and longitudinal and transverse perimeter walls terminating in an upper rim defining an opening through which articles may be placed in and removed from the tray, the perimeter walls being inclined outwardly with respect to the vertical with the rim of each tray having the same dimensions regardless of the height of the tray; a latch handle rotatably mounted on each transverse perimeter wall about an axis located below the datum plane by a first predetermined distance d1; and a latch hook protruding outwardly from each transverse wall and located above the datum line a second predetermined distance d2, the latch handle having a locking tab arranged to engage an associated latch hook of an above positioned tray when the latch handle is rotated to a closed position.

17. The invention of claim 16 wherein the latch handle is formed with a central section and a stub axle extending outwardly from the central section along the axis of rotation and wherein the transverse perimeter walls define opposed openings for receiving the stub axles.

18. The invention of claim 17 wherein the transverse perimeter walls include a recessed center section located between perpendicularly extending side walls, the side walls defining the openings for the latch handle stub axles.

19. The system of claim 18 wherein the peripheral walls include an inwardly stepped section joined to the bottom with the stepped section providing a mating interface with the upper edge of the peripheral walls of a below positioned tray and defining the datum plane so that when the trays are in a stacked relationship the peripheral walls of each container are substantially aligned.

20. The system of claim 19 wherein the longitudinal peripheral walls of the tray define a plurality of vertically oriented opposing divider receiving guides.

21. The system of claim 20 further including a cover having longitudinal and transverse perimeter sections with the transverse sections having a recessed center portion with a protruding latch hook on each transverse center portion section, the perimeter sections defining an overcut portion adjacent the bottom thereof with a horizontally oriented shelf arranged to engage the rim of an underlying tray, the latch hook being positioned above the shelf by the distance d2.