Stackable modular container having hinged bottom doors for collecting and storing materials

Abstract

A storage bin system is provided that is frameless and comprises stackable, modular bins each having a door in its bottom. The individual bins can be stacked with all bins above the bottom bin in a stack having their bottom door initially open, permitting bottom to top loading of the bins in the stack. As a lower bin is filled, the bottom doors of a second bin stacked immediately above it are closed, causing material inserted at the top of the bin stack to be collected in the second bin. Adapters are provided that hang on the top edges of the lower bin to receive and support the second bin stacked above the first bin. The bins may be used for storing many types of things including recyclable waste, toys and dirty clothes.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to storage containers, and more particularly, to stackable, modular storage containers.

BACKGROUND OF THE INVENTION

[0002] Storage containers are used in so many applications that they cannot all be enumerated here. Typical applications are found in homes, apartments, kindergarten schoolrooms, preschool rooms, laundry rooms, and many other locations. Types of materials that are placed in such storage containers include, but are not limited to, garbage, recyclable waste, toys, dirty laundry, shoes, and for many other things.

[0003] In recent years, for example, increasing efforts and a corresponding public awareness have been directed toward the reclamation and re-use of recyclable waste and like materials, such as aluminum cans and containers, glass containers and other glass articles, plastic containers, and newspaper and similar paper products, which have traditionally been simply discarded. As is known, considerable cost savings, as well as more efficient management and use of natural resources necessary to produce such items may be realized by reclaiming and recycling such items. In addition, the reclamation and re-use of recyclable waste reduces the amount of such items being placed in landfills which are rapidly becoming filled, and has necessitated ocean dumping and the attendant pollution of our oceans and the ecological harm resulting therefrom. To this end, many towns and municipalities throughout the United States are enacting ordinances requiring that homeowners and business establishments separate waste into different categories. For example, trash which will be disposed of at a garbage damp, landfill site and/or incineration plant, recyclable materials which may be re-used in producing new products, and compostable materials which may be composted in a backyard composter or collected for centralized composting.

[0004] Recycling was introduced long after refuse collection had been in place and has been treated as an independent operation. At first recyclable materials were piled separately, then bundled, then placed in a container, then more sophisticated containers were developed having multiple or divided containment areas. The problem with multiple bin units was that the contents had to be emptied into different larger containers making this a difficult task that required lifting all the contents and blocking the contents that were not to be dumped into the larger container. Residential recycle bin designs have been constrained by cost and lifting weight. The higher demand for separation of different recyclables, along with the higher amount of recyclable material used in packaging and collected today, has resulted in the need for two or more bins. Simple bins have been made stackable to reduce space and carts have been made to move the bins to the curb.

[0005] Presently, the most common method of collecting and separating recyclable materials is the use of separate bins for each type of recyclable material such as cans, glass, plastic and paper. However, this often requires several bins and utilizes substantial floor space. A bin must be available for each type of recycled waste material. When one recycling bin is full a spare bin is placed on top of the full bin. However, the spare bins must initially be placed elsewhere and take up additional space. Such recycle bins are presently a simple rectangular box with a top edge that facilitates lifting, and drain holes in the bottom since there is no cover from rain or snow. The size is determined by the lifting weight for the worst case scenario of wet newspaper.

[0006] Recycle bins with wheels have not been commercially successful because the maximum lifting weight does not allow the height of the bins to reach an ergonomically suitable height to wheel the bins. If the maximum size bins were stretched to a free standing height of about 34 inches, then the base of the bins would be too small to be stable. The conventional 32 gallon wheeled refuse containers are disliked by collection workers for their instability, and the narrow wheel base of the cylindrical shaped containers makes them difficult to roll. This has led to square based containers to increase the width of the wheel base, and to prevent rolling in the wind when the containers are empty, even though the cylindrical shape provides greater structural integrity and simplicity of manufacture. The larger 60 gallon containers often will not be emptied by collection workers due to their excessive weight.

[0007] A recycling cart is disclosed in U.S. Pat. No. 5,192,092 to DiBenedetto, but it is expensive and would have to be unloaded and taken away from the curb or risk theft. The cart would then be brought back to the curb to pick up the empty bins. The cart still requires bins of the type described above which the owner may already have. However, the owner's bins may not fit the cart since recycle bins vary in dimension thus making universal cart manufacture difficult. The bins must also be secured and unsecured to the cart for rolling. The cart and bins of U.S. Pat. No. 4,821,903 to Hayes has the same problems of expense and theft but the bins do not require securing. The bins are however custom made and are expensive to make.

[0008] The stackable refuse system of U.S. Pat. No. 5,445,397 to Evans offers a more economically viable solution for a multiple bin unit. It has the advantage of nesting which allows for efficient distribution and storage of the bins. It also has the advantage of forming a rigid entity from several bins by means of a flexible strap with a clasp, thus providing the required ergonomic height for tilt and rolling and reducing the effective lifting weight upon detachment. However, the method of securing the bins to form a rigid entity is not a system that secures individual bins to each other (adjoining bins) but rather a strap that compresses a number of bins and wheel assembly to form a single rigid entity that can be tilted. The wheels must be added by a separate wheel assembly because there is no individual means of securing wheels to of bottom bin, or must be added by the alternate embodiment of a cart, to overcome this problem. The wheels are not integral with the bottom bin resulting in additional user labor. The preferred embodiment has bins with lids because if stacked without the lids it results in the unit sloping over the wheels. The alternative embodiment uses an expensive metal tubing cart which also requires lids to avoid the sloping problem, but then allows for the elimination of the flexible strap and having to bend over to pick it up. In addition, the design cannot be blow molded. The wheel base will not nest within itself thus adding to the distribution cost, and the metal frame cart is even more cumbersome to ship. The lids add expense and require the additional labor of securing or removal upon dumping and then re-assembly.

[0009] Wheeled objects that are tilted for rolling have never been secured together from their free standing position to form a single entity wheeled cart whether hitched or castor wheeled. Two wheel tilt and roll containers or any similar tilt and roll device, such as a luggage container, have never been hitched at the top end nor has there been a way to tilt the devices after being hitched. Trains of containers have been made for commercial application using hitched or linked dollies. These systems have the following disadvantages. They require an independent dolly, the dolly has 4 wheels for stability, some or all of the wheels must have the ability to swivel to allow the train to go around corners, the castor wheels are small to keep reduce cost as well as reduce over all height to minimize vertical instability. The small wheels and instability limit the terrain over which the container train may travel to smooth surfaces due to the inability of small wheels and swivel castors to roll over large bumps. The operator must be in a bent over position to connect the containers to dollies. The connections between containers in the train must be undone and redone because the container dolly units cannot move independently in the vertical direction, and the upper lateral movement is aggravated due to the height of the container since they are free to move independently at the top. Unless all four of the castors on the dollies are swivel type, the direction of train movement cannot be reversed and containers must be locked to the dollies, thus limiting versatility.

[0010] One problem with stackable bins, as mentioned above, is that access is only provided to the top bin in a stack. One variation of stackable bins that provide access to all bins in a stack are open-front bins. These bins take the form of a standard rectangular storage bin, with a cutout in the front of the bin. See U.S. Pat. No. 5,190,156 which provides an example of bins that allow front loading a bin when it is on the bottom or in the middle of a stack of bins. While access is provided to all bins in the stack, effective capacity is diminished by the front opening. The usable height of the storage is the height of the bin, minus the height of the opening. The bigger the opening, the less effective capacity and the more likely it is that material will fall out. Additionally, the front-loading method often requires some shaking of the container to make use of even the effective height of the container. This shaking activity to level the contents is more problematic in a stacked configuration. Items falling out of the bin are especially problematic for glass items. The risk of items falling out increases when moving the bins from the house to the curb and, especially, when recyclable collectors are lifting the bins from the ground to unload them into a truck. An additional disadvantage of this system is that recycle material or refuse is visible from the front. Front-loading is also not ideal for compressible recyclable materials, such as cardboard containers and plastic cartons, because they are not compressed as much to take up less volume.

[0011] The set of sorting-stacking bins taught in U.S. Pat. No. 4,161,252 provides stacking containers with an angled front wall. This provides access, in the horizontal plane, or a plane slightly off the horizontal, when the bins are stacked. While this design alleviates the problem of unsightly material and potential spill out of material, they also do not maximize storage volume because the angled front requires a larger footprint without full vertical volume. These bins also tend to be fairly unstable due to their horizontal center of gravity being offset from the center of the footed position of a stack of bins.

[0012] The prior art focused primarily on the ability to segregate different types of recyclable material to different bins in the same vertical stack. Since the start of curbside recycling, recycling companies have become more sophisticated. Today much of the sorting of material is performed automatically at a recycling company site. This lowers the burden on the consumer as well as the recycle collection process by allowing different materials (glass, plastic, Styrofoam, aluminum, etc.) to be collected in one bin by the consumer and the collector. This eliminates the need for sorting at home, but leaves the issue of temporarily storing more and more recyclable materials at the residence. While an immediate choice is to simply use a large, trash-can-like, bin to store the materials, this raises ergonomic issues. A large container full of glass or paper is too heavy for an individual to repeatedly lift and large standardized containers and automated lift-and-load equipment are too expensive to deploy in many towns and cities.

[0013] Thus, there is a need in the prior art for a new stackable recycling system that can meet the ergonomic needs of both consumers and curbside recycling personnel, and that can reduce the floorspace required to store increasing amounts of recyclable material between pickups.

SUMMARY OF THE INVENTION

[0014] The foregoing need in the prior art is satisfied by the present invention. A novel recycling bin system is provided that is frameless and comprises stackable, modular bins each having a door in their bottom. The individual bins can be stacked with all bins above the bottom bin in a stack having their bottom door open. The bins may be used for collecting and/or storing many types of items including recyclable waste material, toys and dirty laundry in places such as homes, apartments, kindergarten schoolrooms, pre-school rooms and laundry rooms. Thus, for example, if a user normally uses three bins to collect cans during each collection cycle, they will initially stack three recycling bins for that purpose. As cans are deposited into the top of the stack of three recycling bins, they fall into the lower most bin until it is filled. The bottom door of the middle bin is then closed, isolating that bin from the lower most bin. Subsequent cans are then collected in the middle bin until it is filled, and the bottom door of the top bin is then closed. Finally, the cans are collected in the top recycling bin. When the recycling bins are to be moved to another location for recycling of their contents, each bin is picked up and moved in turn starting with the top recycling bin.

DESCRIPTION OF THE DRAWING

[0015] The invention will be better understood upon reading the Detailed Description in conjunction with the drawings in which:

[0016] FIG. 1 is a side view of my novel, stackable bins stacked for use in collecting empty cans;

[0017] FIG. 2 is a top view of one of my novel, stackable bins showing its bottom doors closed;

[0018] FIG. 3 is a top view of one of my novel, stackable bin showing the bottom doors opened;

[0019] FIG. 4 shows the doors used to open or close the bottom of my novel, stackable bin;

[0020] FIG. 5 shows a side cutaway view of my novel, stackable bins showing how the bins can be stacked on each other, and the bottom doors opened and closed;

[0021] FIG. 6 shows a section of a hinge portion on the bottom of a bin, and a mating section of a hinge portion on the edge of each door at the bottom of a bin; and

[0022] FIGS. 7 a and 7b show support adapters that are placed on the top lip of the bins to permit stacking them.

DETAILED DESCRIPTION

[0023] The needs of the prior art are satisfied by my invention. I provide a stackable, modular, frameless container system that utilizes a plurality of new, hinged bottom door bins. The bins each have means for supporting another bin stacked on top if it, and the stacking allows bottom-to-top loading of multiple, vertically stacked bins. The stacked bins thus form a virtually tall container that can be transported and emptied in physically smaller compartments in the form of the individual bins. Thus, the individual bins allow ergonomic lifting and unloading of waste in the bins of the system in stages.

[0024] The following detailed description uses the example of a recycling bin and stacking a plurality of such bins to meet the great need in the recycling field for a container system such as provided with the present invention. However, it should be clearly understood that the present invention is not limited to such an application. Many other applications are contemplated. For example, in a home, apartment, kindergarten schoolroom, pre-school room, laundry room, and many other locations, and for many other applications, my novel stackable storage bins may be utilized. Other examples include the consolidation of medical or radioactive waste in a stack of containers where the size of the shipment container is regulated.

[0025] For example, in a pre-school setting there are many toys used during each day that must be picked up and stored at the close of the day. By using the novel stacking bins of the present invention the task is made easier. Between classes, the instructor can roll a stack of such bins around, collecting all the toys. The toys end up in individual bins using the method described above. After pick-up is complete, the individual bins can be un-stacked and returned to either storage shelves or to an area on the ground accessible by the children. Similar toy clean-up mechanisms would apply to the home. This provides time-saving as well as obvious ergonomic advantages.

[0026] For another example, my novel, stackable bins may be used as a hamper for dirty laundry storage. For aesthetics the containers may be decorator colors and have prints thereon. In such an application a top or lid will be provided for the bin at the top of the stack. The top can be a conventional snap on lid as already known in the art, or it can be a cover that easily and removable mounts on the top bin in a stack and has a hinged lid. When it is time to wash individual bins may be much more easily transported to a washing machine or laundromat. The individual bins are light enough that even smaller children can lift them and carry them for a parent. In the prior art a full hamper can be quite heavy and cannot be carried by a person with any back trouble due to its weight, or by a child.

[0027] My novel stacked bins allow top-loading, or “piling” of a class of recycle material into all bins in a container system stack, thereby facilitating compression of the recycle materials and providing an even distribution of such material in all the bins.

[0028] In addition, the stacked configuration of my novel stacked bins also eliminates the need for locating empty bins separate from bins that are filled or are being filled so it maximizes storage volume over the container system footprint.

[0029] Further, my novel stacked bins provide bottom-to-top loading of all bins while preventing unsightly exposure of contents or accidental spill out of contents from the bins. As a lower bin in a stack is filled the bottom doors in the next higher bin may be closed without requiring access to the doors through the top of the stack.

[0030] The individual bins may be nested one inside the other to create a stack that takes up less space for storage and shipment, yet permits my novel stacked operation.

[0031] In FIG. 1 is shown a side view of three of my novel recycling bins 11a, 11b and 11c stacked into a virtually tall container for use in collecting empty cans. Inside, at the bottom of each of bins 11a-11c are a pair of doors 12a and 12b that can be placed in a closed position as shown for the bottom most bin 11c, or can be placed in an open position as shown for bins 11a and 11b. The two curved arrows in the top most bin 11a indicate how the doors 12a and 12b swing to their open and closed positions. Empty, recyclable cans 13 are inserted at the top at bin 11a and they fall down through bins 11a and 11b into bin 11c. Closed doors 12a and 12b of bin 11c retain the cans 13 therein.

[0032] When bottom bin 11c is full of cans 13, the doors 12a and 12b of middle bin 11b are closed. How the bottom doors can be closed for lower bins when they are stacked four or five high is described further in this specification. As more cans 13 are inserted into the top of bin 11a they fall through bin 11a into bin 11b. Similarly, when bin 11b is full, doors 12a and 12b of the top bin 11a are closed and cans 13 then are retained in top bin 11a. While cans 13 are used for illustration in this specification, it should be noted that other types of waste material to be recycled may be placed in the bins. Other examples are paper, plastic and glass.

[0033] When the bins 11a, 11b and 11c are to be emptied, the user merely picks up bin 11a and places it at curbside for recycling pickup, followed by bin 11b and then bin 11c. There is no heavy load of trying to carry all three bins at the same time. Each of bins 11a-11c has a lip 14 around its top edge that facilitates in picking up the bins for carrying. Such lips are known in the prior art.

[0034] If all three bins 11a-11c are all filled before recycling pickup, another empty bin 11 (not shown) may be placed on top of bin 11a with its doors 12a and 12b in the closed position. Conversely, if only bins 11b and 11c are filled, bin 11a is removed and set aside, and only bins 11b and 11c are individually taken to curbside for collection.

[0035] Exactly how bins 11a-11c stack and restack on each other is described in greater detail further in this specification. Each of bins 11a-11c have sloped side walls 16, as seen in FIG. 1, facilitating nesting the bins together for shipping or storage when they are not in use.

[0036] A stacked group of bins, such as bins 11a-11c, may be placed on a rollable dolly 36 to more easily move them around.

[0037] In FIG. 2 is shown a top view of one of my novel recycling bins 11 showing its bottom doors 12a and 12b in their closed position to retain waste material in bin 11. Each of doors 12a and 12b has reinforcing ribs 15 that provide structural stability to the doors to help support the weight of waste material in bin 11. When in their closed position the edges of doors 12a-12c rest on ledges around the inside bottom of bin 11 for support. Other than ledge 22, these ledges are not seen in FIG. 1, but are better shown and described with reference to FIG. 3.

[0038] Carry lip 14 is formed around the top periphery of bin 11 at the top of sloped side walls 16. There is a shown only one representative corner support adapter 18 and one representative mid-wall support adapter 19 that sit on top of lip 14 and permit stacking of bins. This is done as not to detract from an understanding of the construction features of bin 11. In actual use there will be one corner support adapter 18 at each top corner of bin 11 on carry lip 14. Similarly, when they are used, there may be at least one mid-wall support adapter 19 at the middle of the side walls 16 of bin 11. These supports are used to stack bins 11 as shown in FIG. 5. Both these adapters are described in detail with reference to FIGS. 7A and 7B.

[0039] Each corner support adapter 18 provides a ledge 29 and each mid-wall support 19 provides a ledge 34. The bottom edges of a bin 11 stacked on top of the bin 11 in FIG. 2 will sit on these ledges 29 and 34. With four corner support adapters 18 each corner of the stacked bin 11 are supported, and mid wall support is provided as needed. The need for the mid-wall support adapters 19 is dependent on the weight load to be carried by all the bins stacked above bin 11 in FIG. 2. These support adapters are described in greater detail with reference to FIGS. 5 and 7.

[0040] FIG. 3 shows a top view of one of my novel recycling bins 11 with its bottom doors 12a and 12b in their open position to create a hole 21 through the bottom of bin 11. A side view of these doors in their open position is seen in FIG. 1. As previously described, doors 12a and 12b are left open when a stack of bins are provided to permit bottom-to-top loading.

[0041] Only one representative corner support adapter 18 and one representative mid-wall support adapter 19 are again shown. The reason only one of each is shown, and their function, are described above with reference to FIG. 2.

[0042] In FIG. 3 are shown support ledges 22 around the inside of the bottom edges of the four side walls 16. When doors 12a and 12b are in their closed position their periphery sits on these support ledges 22 to support the weight of waste (not shown) in bin 11.

[0043] FIG. 4 shows the doors 12a and 12b used to open or close the bottom of my novel recycling bin 11. Each of the doors has reinforcing ribs 15 that provide structural stability to doors 12a and 12b to help support the weight of waste material in bin 11 on top of the doors. Each of doors 12a and 12b also has a hinge element 20a molded as a part thereof. Each of the hinge elements 20a snaps into a mating hinge element 20b that is molded as part of bin 11 at the inside bottom of the longer dimension side walls 16. These hinge elements are described in greater detail with reference to FIG. 6.

[0044] FIG. 5 shows a side cutaway view of my novel recycling system comprising two recycling bins 11a and 11b, showing how the bins can be stacked on each other, and the bottom doors 12a and 12b opened and closed.

[0045] The lower most bin 11b has its doors 12a and 12b closed to capture waste in bin 11b. On top of carry lip 14 of bin 11b are shown two representative mid-wall supports 19. The upper most bin 11a has its doors 11a and 11b in their open position to permit bottom-to-top loading of the bins. In stacking bin 11a on top of bin 11b the bottom edge of bin 11a is supported by ledges 34 of mid-wall support adapters 19. Being as FIG. 5 is a side cutaway view, corner support adapters 18 are not seen in this Figure. There is a corner support adapter 18 on lip 14 at each corner of bin 11b. This is better seen with respect to FIGS. 2 and 3. In combination, the support ledges 34 of mid-wall support adapters 19 and ledges 29 of corner support adapter 18 (not shown in this Figure) provide sufficient support for bin 11a to be held on top of bin 11b.

[0046] Through the side wall of each of bins 11a and 11b there are located holes 23a and 23b. They are used to close bin doors 12a and 12b. When bin 11b is full of waste to be recycled, the doors 12a and 12b of upper bin 11a need to be closed so that any further waste is retained in bin 11a. Bin 11a being the top bin in the stack, all that needs to be done is reach inside the bin and close doors 12a and 12b. In typical use, for stacks of two or three bins, all that needs to be done is to reach inside the unused bins 11 and close doors 12a and 12b of the bin above a filled bin. However, if bin 11a is a middle bin in a stack of bins it is not easy to reach down through two or possibly three stacked bins to close doors 12a and 12b above a full bin 11. In this case a thin instrument 24, such as a pencil 24, ball point pen or screw driver blade is inserted through hole 23a to push against and close door 12a, and through hole 23b to push against and close door 12b.

[0047] FIG. 6 shows a section of a hinge portion 20a on one edge of each of doors 12a and 12b, and a mating section 20b of a hinge portion on the inside bottom of a bin 11. Each of hinge segments 20a has a small protuberance 35 at either end thereof, and at either end of each mating hinge segment 20b there is a recess 36. To assemble doors 12a and 12b to the inside bottom of a bin 11, as shown in FIGS. 2 and 3, hinge segments 20a are forced between corresponding pairs of hinge segments 20b where the protuberances 35 snap into recesses 36 and create a hinge.

[0048] FIGS. 7 a and 7b show support adapters that are placed on the top lip 14 of bins 11 to permit stacking of bins 1 as shown in FIG. 5. FIG. 7a shows a corner support adapter 18. Adapter 18 has horizontal portions 27a and 27b that rest on top of the carry lip 14 of two adjacent sides of bin 11 at a corner. Portions 26a and 26b hang over the outside of carry lip 14 to help retain corner adapter 18 in place. When corner support adapter 18 is placed on top of carry lip 14, parts 28a&b hangs down inside bin 11. Horizontal ledge 29 of each corner support adapter 18 receives and supports a corner of a bin 11 stacked above it.

[0049] FIG. 7 b shows a mid-wall support adapter 19. Adapter 19 has a horizontal portion 32 that rests on top of the carry lip 14 of a bin 11. A portion 31 hangs over the outside of carry lip 14 to help retain adapter 19 in place. When mid-wall support adapter 19 is placed on top of carry lip 14, part 33 hangs down inside bin 11. Horizontal ledge 34 receives and supports a mid-side edge of a bin 11 stacked above. As previously described, mid-wall support adapters 19 are used as needed and their need depends on the anticipated weight of all bins 11 stacked above. Cans are relatively light and mid-wall support adapter 19 are typically not needed.

[0050] While what has been described herein is the preferred embodiment of the invention, it will be understood that numerous changes may be made without departing from the spirit and scope of the invention. In one alternative embodiment of the invention, if it is not desired to be able to nest bins 11 inside of each other for shipping and storage, support adapters may be molded as part of bins 11. In addition, one door instead of two may be located at the bottom of each bin 11.

Claims

1. A vertically stackable bin for holding material, a plurality of the bins being stacked on top of each other, each bin comprising: a front wall, a rear wall and a pair of opposite side walls, all formed of self supporting material, and each wall has a top edge and a bottom edge; and a closure mounted in the bottom of the bin that is closed to hold the material in the bin, and the closure is opened to permit material inserted into the bin to pass through the bin.

2. The invention in accordance with claim 1 further comprising means to receive and support a second bin stacked on top of the first bin.

3. The invention in accordance with claim 2 wherein when a plurality of bins are stacked on each other to hold material, the closure of a first, bottom most bin is closed and the closure of the upper bins are opened.

4. The invention in accordance with claim 3 wherein when a bin in the plurality of stacked bins is full the closure of a bin stacked immediately on top of the full bin are closed and subsequent material inserted into the plurality of stacked bins is contained in the bin the closure of which has just been closed, and this is repeated until all bins are full of material.

5. The invention in accordance with claim 4 wherein material to be inserted into the plurality of stacked bins is inserted in the top bin in the stack and the bins are filled in a bottom-to-top manner.

6. The invention in accordance with claim 5 further comprising a ledge on the bottom edge of each bin, the ledge supporting the bin closure when it is in its closed position to support the weight of material in the bin.

7. The invention in accordance with claim 6 further comprising an aperture through a wall of a bin, and a force is applied through the aperture to cause a closure to be placed in its closed position.

8. The invention in accordance with claim 7 wherein the closure of a bin comprises a pair of doors that are movably connected to the bottom edge of two opposing walls of the bin, and there is an aperture through each of the two opposing walls through each of which the force is applied to push door to its closed position.

9. The invention in accordance with claim 8 further comprising hinges that cause the doors to be movably connected to the bottom edge of two opposing walls of the bin.

10. The invention in accordance with claim 9 wherein the means to receive and support a second bin stacked on top of the first bin comprises means that are placed on the edges of the walls of a first bin to receive and support the second bin.

11. The invention in accordance with claim 1 further comprising a ledge on the bottom edge of each bin, the ledge supporting the bin closure when it is in its closed position to support the weight of material in the bin.

12. The invention in accordance with claim 11 wherein the means to receive and support a second bin stacked on top of the first bin comprises means that are placed on the top edges of the walls of a first bin to receive and support the second bin.

13. The invention in accordance with claim 12 further comprising an aperture through a wall of a bin, and a force is applied through the aperture to cause a closure to be placed in its closed position.

14. The invention in accordance with claim 13 wherein the closure of a bin comprises a pair of doors that are movably connected to the bottom edge of two opposing walls of the bin, and there is an aperture through each of the two opposing walls through each of which the force is applied to push door to its closed position.

15. The invention in accordance with claim 14 further comprising hinges that cause the doors to be movably connected to the bottom edge of two opposing walls of the bin.

16. The invention in accordance with claim 6 wherein the means to receive and support a second bin stacked on top of the first bin comprises means that are placed on the top edges of the walls of a first bin to receive and support the second bin.

17. A storage bin for holding material, each bin comprising: a front wall, a rear wall and a pair of opposite side walls, all formed of self supporting material, and each wall has a top edge and a bottom edge; and doors mounted in the bottom of the bin to two opposing walls, the doors being closed to hold the material in the bin, and the doors being opened to permit material inserted into the bin to pass through the bin.

18. The invention in accordance with claim 17 further comprising a ledge on the bottom edge of the walls of each bin, the ledge supporting the bin doors when they are in their closed position to support the weight of material in the bin.

19. The invention in accordance with claim 18 further comprising an aperture through each of the last mentioned two opposing walls through which a force is applied to push a door to its closed position.

20. The invention in accordance with claim 19 wherein when a plurality of bins are stacked on each other to hold material to be stored, the doors of a first, bottom most bin are closed and the doors of the upper bins are opened, and wherein when a bin in the plurality of stacked bins is full the doors of a bin stacked immediately on top of the full bin are closed and subsequent material inserted into the plurality of stacked bins is contained in the bin the doors of which have just been closed, and this is repeated until all bins are full of material.