US3425471A - Plastic container with double lid - Google Patents

Description

Feb. 4, 1969 G. YATES, JR

PLASTIC CONTAINER WITH DOUBLE LID Filed Dec.

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United States Patent 3,425,471 PLASTIC CONTAINER WITH DOUBLE LID George Yates, Jr., Glendale, Califi, assignor to Bennett Industries, Inc., Peotone, 111., a corporation of Delaware Filed Dec. 1, 1966, Ser. No. 598,471 US. Cl. 150-48 Claims Int. Cl. B6511 51/18 ABSTRACT OF THE DISCLOSURE The invention relates to plastic containers which have flexible side walls and which require a special seal at the top so that, should the container ever be dropped when filled with liquid contents, the seal will not be broken.

The invention in essence consists of a flexible container usually in the form of a pail which has a reinforced thick rim to accommodate two lids, one lid being a flexible plastic lid having an annular pocket fitting over the thick rim, and the other being a reinforcing top of relatively stiff material, preferably metallic, which also has an annular pocket fitting over the exterior of the pocket of the plastic lid, there being provided a series of circumferentially spaced clamping elements which are bent to seal both of the lids upon the thick rim, in such a way that the wall which forms the pocket of the plastic lid serves as a sealing gasket.

There has been very considerable attention given to the fabrication of plastic containers in various forms which include pails and buckets. In order to make plastic containers strong enough for many purposes, the plastics which are available are made in somewhat flexible form so that they will yield and not break as would a stiff plastic container under the impact of an external blow. Being yieldable, however, has certain disadvantages especially when the container must be tightly sealed. If the container is to be filled with a material such as paint, for example, the container must be sealed with great assurance so that it will not leak under any circumstances until finally opened for use. One test which the industry has established is the five foot drop test, which means that a container filled and sealed must be capable of being dropped a distance of five feet striking on edge and under such conditions have the seal such that it *will not be broken or damaged. Even though plastic containers can be provided with thickened rims in order to assure a certain stiffness for sealing a cover in place, even a thickened rim has a degree of flexibility which is apt to yield during shiprnent and thus cause the container to spring a leak at the top.

It is therefore among the objects of the invention to provide a new and improved plastic container which has a special reinforced double seal at the top which supplies a certain degree of stiffness as well as sealing qualities to assure that the seal will remain tight even though the container is subjected to rough handling.

Another object of the invention is to provide a new and improved plastic container with a double seal at the top consisting of an inner flexible, reusable lid and an outer stiff, temporary lid which is used for shipment and 3,425,471 Patented Feb. 4, 1969 sale, but which after being removed by the user can be discarded.

Still another object of the invention is toprovide a new and improved plastic container with a double seal serving as a closure, the double seal being made up of a reusable inner lid which can be easily removed and replaced an indefinite number of times with sufiicient tightness to make the container airtight, and an outer lid which provides not only a necessary degree of stiffness but also clamps which anchor in place around the inner lid and make the perimeter of the inner lid serve as a sealing gasket.

Still another object of the invention is to provide a new and improved plastic container 'with a relatively stiff bottom and a double sealed top arranged in such fashion that the containers when full can be stacked readily one upon another.

Still another object of the invention is to provide a new and improved plastic container equipped with specially formed bosses for the accommodation of a wire handle, the bosses also serving as a means for limiting the nesting of one empty container into another so that they will not stick together when stored in empty condition.

With these and other objects in view, the invention consists in the construction, arrangement, and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a side prespective view of an empty container.

FIGURE 2 is a fragmentary longitudinal sectional view through one of the bosses which accommodate the wire handle.

FIGURE 3 is a side elevational view partially broken away showing multiple containers stacked in empty condition.

FIGURE 4 is a persepctive exploded view of the double sealing lids.

FIGURE 5 is a fragmentary longitudinal sectional view showing two full containers stacked one upon the other with both lids in place upon them.

FIGURE 6 is a fragmentary longitudinal sectional view showing the inner lid in position.

In an embodiment of the invention chosen for the purpose of illustration there is shown a container 10 in the form of a pail having a closed bottom 11 and an open top 12 and providing a chamber 13 for sundry contents, usually liquid contents. Bosses .14 on opposite sides provide for the attachment of a bail or handle 15. The closed bottom is relatively thicker than a side wall 16 of the container, the side wall 16 therefore being somewhat more flexible. Extending outwardly and downwardly from the bottom is a flange 17 which provides a shallow recess '18 under the bottom and a peripheral corner -19. The side wall 16 tapers slightly inwardly toward the bottom so that the peripheral corner 19 is of diameter slightly smaller than the inside circumference of a thick rim 20 at the open top, thereby to provide for nesting of empty containers, as shown in FIGURE 3. The boss 14, previously described, is of narrow, hollow construction so that it can be molded simultaneously with the molding of the container. When nested as shown in FIGURE 3, a lower edge 21 of each boss is adapted to rest upon the top of the thick rim of the next lower container at a location such that the corner 19 is clear of the inner face of the side wall 16 and in this way prevent empty'containers from sticking together in empty condition, as plastic containers are likely to do. A hole 22 is provided in 3 each boss into which a bent end 23 of the handle 15 is inserted.

The thick rim 20, previously described, has an outwardly convex perimeter 25 forming an undercut 26, whereas the inside of the thick rim is flush with the inside surface of the side wall 16. In practice it 'has been found that a thick rim having a transverse dimension in excess of double the thickness of the side wall 16 is advantageous for the purpose required.

For sealing the container for storage and shipment there are provided multiple lids, indicated generally by the reference characters 27 and 28. The lower lid 27 which, in order to differentiate between the two, will be hereinafter referred to as a flexible cover, is of relatively thin flexible plastic material, for example, any suitable synthetic thermoplastic resin which will retain its flexibility and resilience during use. The flexible cover comprises a closed central portion 29 at the edge of which is a peripheral wall 30 bent to form an annular pocket 31. The annular pocket 31 has a form and size only slightly smaller than the form and size of the exterior of the thick rim 20 so that, after the flexible cover is stretched and fitted over the thick rim in the position shown in FIGURE 6, the wall 30 will return to its initial position and seal itself around the thick rim. A skirt 32 has an annular inwardly extending portion 33 which underlies the undercut 26 in order to hold the flexible cover in position. There may also be provided an annular stepped portion 34 terminating in an annular horizontal flange 35.

The central portion 29 may, if desired, be provided with recessed radially extending reinforcing ribs 36 which extend radially outwardly from a central depression 37. The ribs 36 end just short of an annular substantially vertical inner wall 38 of the flexible cover which is adapted to lie snugly against the inner face of the side wall 16 of the container, thereby to further enhance the seal.

The upper lid, which will hereinafter for differentiation purposes be designated as a top, is preferably of metal, usually sheet steel, frequently galvanized, which serves as an inexpensive cover ultimately to be thrown away. The top 29 includes a central portion 40 at the circumference of which is a clamping bead 41, the wall thickness of which is substantially the same as the thickness of the central portion 40. The clamping head is bent to form an annular pocket 42 which is adapted to fit snugly over the exterior of the peripheral -wall 30 of the flexible cover 25. An inner wall 43 of the clamping head 41 is of substantially the same height as the inner wall 38 of the flexible cover. A riser 44 forms a step 45, the riser having an inside diameter slightly greater than the diameter of the corner 19, so that when containers in filled condition are stacked one upon the other the flange 17 of the upper container is confined in central position upon the top of the next lower container, as shown advantageously in FIGURE 5.

Additional stiffening and strengthening of the flexible cover may be provided by a downwardly convex stiffening bead 46 which is at the bottom of the inner wall 38 of the annular pocket 31.

When the container is to be filled and sealed, liquid contents 50 are placed in the container until the chamber .13 is filled to approximately the level 51. The flexible cover 27 is then applied in position as shown in FIGURES and 6. This is sufficient to seal the contents but not suflicient to reinforce the seal suflicient to stand shipment. The top 28 is then applied so that the clamping head 41 is forced over the peripheral wall 30 of the flexible cover. To anchor the clamping head in position, tabs 52, of which there are many spaced circumferentially around the perimeter of the clamping head 41, are bent forcibly inwardly to the position shown in FIG- URE 5. Bent into position as shown and described, the clamping bead 21 serves to compress the peripheral wall 30 against the thick rim 20 so that the peripheral wall 30 in effect serves as a gasket. The tabs can be effectively forced inwardly by employing a suitable back-up or buck (not shown) against the inner wall 43 during the clamping operation. In this way the closure or seal for the container is a double reinforced seal, the flexible cover serving to assure airtight closure for the open top of the container and the reinforcing stiff top 28 forming, with the thick rim 20, an extremely stiff unyielding top assembly structure which is capable of withstanding handling customarily experienced during shipment.

When the contents of the container are to be used, the tabs are bent to released position, which can be readily done by inserting a suitable tool such as a screwdriver into slots 53 and the top 28 in this manner pried loose. The top can then be discarded and the flexible cover then removed by lifting upon the skirt 32 to stretch the peripheral wall 30 sufficient to release the flexible cover. Thereafter, in the event that the liquid contents are not entirely used, the flexible cover can be replaced with the peripheral wall fitting tightly enough to form an airtight seal again.

Although plastic containers sealed with a plastic flexible cover as herein described are especially useful in the storage and handling of water based paints, the seal is effective for virtually any type of contents, whether the contents be light or heavy and especially where the container, when full, is to be subjected to relatively rough handling. The containers moreover can be very handily stacked either empty or full and thereby minimize inventory problems.

While the invention has herein been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention.

Having described the invention, what is claimed as new in support of Letters Patent is:

1. A sealed package comprising a container of synthetic plastic resin material having a relatively thin flexible side wall structure with an open top and closed bottom, a peripherally extending substantially solid and relatively thick rim of said material around the open top, said rim being outwardly convex providing an undercut shoulder adjacent the side wall structure, the plastic material of said side wall structure being exposed adjacent said shoulder, and a double seal for said top comprising a flexible cover of relatively thin synthetic plastic resin material, a peripheral wall on said cover including an annular pocket receiving said rim in sealing relationship, said pocket including an inner wall in engagement with the inside of the side wall structure of said container, and a reinforcing top comprising a central portion of stiff relatively nonflexible material having an outside perimeter fitting snugly within said rim, a clamping bead on said reinforcing top including an annular peripheral recess having said rim and said peripheral wall of the cover received therein, elements of said bead being bent around the undercut shoulder of said rim in clamping relationship, said clamp ing bead having inside and outside walls extending to locations beneath said undercut shoulder and being in condition pressed toward each other beneath said undercut shoulder when in attached position on said container.

2. A sealed package according to claim 1 wherein said reinforcing top is of sheet metal.

3. A sealed package according to claim 1 wherein the outside perimeter of the closed bottom is smaller than the inside perimeter of the bead of the reinforcing cover whereby to enable stacking of said packages.

4. A sealed package according to claim 1 wherein there are a pair of bosses on opposite sides of said side wall structure adapted to rest on the next adjacent rim when said containers are stacked in empty condition.

5. A sealed package according to claim 1 wherein there is a laterally open hole in each of said bosses and a bale of wire material with respective ends extending into said holes.

6. A sealed package according to claim 1 wherein outside and inside walls of the annular pocket of the flexible cover are in direct contact with the plastic material com prising respective outside and inside wall surfaces of the side Wall structure of the container.

7. A sealed package according to claim 1 wherein the flexible cover has substantially the same thickness throughout the portions thereof forming said pocket as it does throughout the midportion of said cover.

8. A sealed package according to claim 7 wherein said annular pocket on said cover has inside and outside walls opposite each other at a location below said undercut shoulder and clamped in place by the inside and outside walls of the clamping bead on the reinforcing top.

9. A sealed package comprising a container of synthetic plastic resin material having a relatively thin flexible side Wall structure with an open top and closed bottom, a peripherally extending relatively thick rim of said material around the open top, said rim being outwardly convex and providing an undercut shoulder adjacent the side wall structure, and a double seal for said top comprising a flexible cover of relatively thin synthetic plastic resin material, a peripheral wall on said cover including an annular pocket receiving said rim in sealing relationship, said pocket including an inner wall in engagement with the inside of the side wall structure of said container, and a reinforcing top comprising a central portion of stiff relatively non-flexible material having an outside perimeter fitting snugly within said rim, a clamping bead on said reinforcing top including an annular peripheral recess having said rim and said peripheral Wall of the cover received therein, elements of said bead being bent around the undercut shoulder of said rim in clamping relationship, said closed bottom being of material relatively stiff and thicker than said side wall structure.

10. A sealed package comprising a container of synthetic plastic resin material having a relatively thin flexible side Wall structure with an open top and closed bottom, a

peripherally extending relatively thick rim of said material around the open top, said rim being outwardly convex and providing an undercut shoulder adjacent the side wall structure, and a double seal for said top comprising a flexible cover of relatively thin synthetic plastic resin material, a peripheral wall on said cover including an annular pocket receiving said rim in sealing relationship, said pocket including an inner wall in engagement with the inside of the side wall structure of said container, and a reinforcing top comprising a central portion of stiff relatively non-flexible material having an outside perimeter fitting snugly within said rim, a clamping bead on said reinforcing top including an annular peripheral recess having said rim and said peripheral wall of the cover received therein, elements of said bead being bent around the undercut shoulder of said rim in clamping relationship, and an annular skirt attached to an outer edge of said peripheral wall, said skirt being yieldable and having a normal position extending obliquely outwardly from the side wall structure.

References Cited UNITED STATES PATENTS 2,851,187 9/1958 Hall 220-91 3,158,282 11/1964 Housz 220-29 3,343,711 9/ 1967 Godshalk 22091 FOREIGN PATENTS 1,142,575 4/1957 France.

JOSEPH R. LECLAIR, Primary Examiner.

US. Cl. X.R. 22029, 91; 2l5-83

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