PLASTIC CONTAINER WITH DOUBLE LOCK LID AND TEAR BAND

Abstract

An all-plastic container comprising the combination of injection molded pail and lid. The lid initially locks onto the container at upper and lower undercuts and seals thereto by virtue of an inverted U-shaped peripheral section. A tear groove is formed in the lid skirt between the upper and lower locks to facilitate removal of the lower lock. The upper lock is segmented so as to make removal of the lid easier once the lower lock is removed. Indicia on the lid shows where the gaps in the lock segments are located. The lower lock may also be segmented to provide drainage for overfill which comes out of the pail when the lid is first applied. The lid and pail are dimensioned to provide a wedge seal between an unflanged pail rim and the top lock and to maintain a strong connection and seal even after the lower lock is removed.

Description

FIELD OF THE INVENTION

This invention relates to plastic containers of the type comprising a pail and a lid which sealingly fits onto the pail without the need for a gasket and further wherein the container provides multiple lid locks, one of which is removed by tearing off part of the lid in the opening procedure.

BACKGROUND OF THE INVENTION

Plastic containers comprising the combination of an open top pail and a lock-on lid or closure are well known and have been in commercial use for shipping and merchandising various products in the United States for many years. The word “lock”, as used in this product area, refers to an undercut-based snap fit between the pail and lid which inhibits removal of the lid, sometimes strongly enough to require the use of a tool or physical alteration of the lid to achieve removal.

Plastic containers of this type have largely supplanted metal containers in many areas including adhesives, food products, paint, wallboard paste, spackling, driveway sealant and other products. They are durable and largely undentable, particularly when made of high density polyethylene, and not subject to corrosion.

The pail and lid are typically injection molded of a suitable material such as high density polyethylene or polypropylene. The seal between the pail and the lid can be achieved by providing a compressible O-ring gasket but this is another part to make and install and, therefore, adds to cost. One multiple-lock container and closure structure is shown in U.S. Pat. No. 5,730,309 to Jiradejnunt et al. This patent discloses a plastic container with a flanged rim that bears against seal rings molded into the end of the lid channel and three locks, two of which are removed in the opening procedure, which procedure involves tearing away the lower part of the lid skirt. The lid thereafter provides only a weak seal and is difficult to remove because the newly-formed bottom of the lid skirt is too close to a pail sidewall feature that forms part of the middle lock.

SUMMARY OF THE INVENTION

The present invention provides a plastic container comprising the combination of an open-top flangeless pail and a lid, both preferably made of injection molded plastic such as polyethylene or polypropylene, wherein a strong lock and a good seal is provided between the pail and the lid without the need for either a gasket or special features such as rim beads and notches on the top of the pail rim or in the lid channel. In this invention, the good seal is preserved even after the opening procedure has been performed; i.e., after removal of the lower part of the lid skirt. In addition, the lid can be readily removed by hand after the initial opening procedure.

In general, these improvements are achieved by providing a pail with a flangeless top rim that wedge-fits into a narrow inverted peripheral channel in the lid and by providing a double-locking structure involving cooperating elements on the container sidewall and lid skirt wherein a top lock helps to maintain the rim seal both before and after the initial opening procedure, and the removal of a bottom lock exposes a newly-formed annular lid skirt edge in a position that affords easy access to the user's fingers for subsequent repeated removal purposes.

Removal of the lower lock is achieved by means of a tear groove that weakens the lid skirt sufficiently to allow removal of the bottom annular ring portion, thereby exposing the new skirt edge mentioned above. The groove is strategically located to provide the advantages detailed above.

In an illustrative embodiment, arrows, indicia or the like are molded into the lid to surface to direct the user to apply a lifting force in certain areas to remove the lid from the container once the lid skirt is torn. In the illustrated embodiment, there are three such indicia in the forms of arrows with the legend “LIFT” molded into the top deck of the lid thereby to eliminate the need for a printing function or the application of a decal. However, both of these alternatives as well as other alternatives, while not preferred, are useable in accordance with the more detailed aspects of the present invention.

Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:

FIG. 1 is a perspective view of a first all-plastic injection-molded container comprising a pail and lid embodying the invention;

FIG. 1A is a perspective view of the FIG. 1 container with the lid removed;

FIG. 2 is a plan view of the inside surface of the lid from the combination of FIG. 1;

FIG. 3 is a plan view of the outside or top surface of the lid of FIG. 2;

FIG. 4 is a side view in section of an enlarged portion of the lid and pail showing how the upper and lower locks are formed;

FIG. 5 is a side view in section showing the upper and lower locks engaged;

FIG. 6 is a composite of side views in section showing how the lid looks after the opening procedure is performed and how containers stack on top of one another;

FIG. 7 is an isometric view of a second embodiment of the invention;

FIG. 8 shows the pail of FIG. 7 with the lid removed;

FIG. 9 is a sectional view of the complete container with the lid attached; and

FIG. 10 is a sectional view with the lid attached and the lower skirt removed.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT

Referring to FIGS. 1-6, there is shown an all plastic container 10 comprising the combination of a generally cylindrical plastic pail 12 and an injection molded lock-on plastic closure or lid 14. In this illustrative embodiment the pail 12 and lid 14 are both injection-molded of high density polyethylene, but other materials such as polypropylene may be used as alternatives.

The pail 12, which in this instance is a 3 ½ gallon pail but can be made in any of a variety of other larger and smaller sizes, comprises a slightly tapered cylindrical sidewall 16 extending upwardly to an enlarged diameter collar 18 which is integral with, but is spaced outwardly from, the wall 16 by ribs 32 and which lies below the upper rim portion 26 as best shown in FIGS. 1A and 5. The collar 18 runs circumferentially around the entirety of the pail 12 and has diametrically opposite ear integral portions 20 which receive a wire bail 22 having a ferrule type plastic handle 24 mounted thereon.

As shown in FIG. 1A the upper rim portion 26 of the open top container 12 is unflanged and, except for a slight taper, is featureless; i.e., it has no notches, flanges or beads at the upper end. A pinch or wedge seal between container and lid is achieved by dimensioning the container rim thickness and the annular lid channel into which it fits to provide a tight fit and a bottoming-out of the flangeless rim into the channel as shown in FIG. 4. On the outer sidewall 16 about 1 inch below the rim is a bead 28 with a sloped top surface which is circumferentially continuous around the pail 12 and forms part of an upper lock to be described. The bottom surface is more radially flat. Approximately 4 inches below the bead 28 is a second radially outwardly extending bead 30 which is preferably notched at six or eight evenly spaced locations and is integral and contiguous with the radially outstanding collar 18. Reinforcing ribs 32 are provided at circumferential intervals of about 1 ⅛″ around the pail. The bead 30, like bead 28, has a downwardly sloped top and a sharp undercut.

Looking at the lid 14, it comprises an inverted U-shaped peripheral channel portion 34 defining a downwardly opening and radially narrow, internal channel 36 which snugly and sealingly; i.e., wedgingly receives the top rim portion 26 of the pail 12 therein. The inverted U-shaped channel peripheral portion 34 comprises an outer wall 38 and a downwardly extending annular inner wall 40 having circumferentially spaced reinforcing ribs 42 as shown in FIGS. 2 and 4. The outer surface of the lid has a recessed deck 44 with the tapered lead surface 46 from the peripheral channel portion 34 to make it easier to stack one of the containers on top of another of like size and design.

In accordance with the invention, an upper lock comprises the combination of the bead 28 on the pail sidewall 16 and three evenly circumferentially spaced semi-annular locking segments 48 forming undercuts 50 on the inside surface of the outer skirt 52 of the lid. When the lid 14 is firmly attached to and seated on the pail 12 the bead 28 fits within the undercuts 50 of the three locking segments 48 to draw the lid 14 onto the flange 26 of the pail 12. In other words, the distance from the top of rim 26 to the lock bead 28 matches the distance from the bottom surface (seen as the top in FIG. 5 because of the inversion) of the channel to the undercut 50.

The lid 14 is molded with a long skirt including the upper wall 30 and a lower portion 52 separated by an interior, circumferential tear groove 56 which is made thin and weak enough to allow the lower portion 52 to be manually torn off. A starter tab 60 is provided to facilitate tearing. Note that the tear groove 56 is well below; i.e., about 1 to 2 inches, by the lock bead 28 which fits into the undercut notch 50 in the inner surface of the lid's upper skirt. Further, the lid skirt stands well out from the container sidewall at the tear groove 56. This gives a large handhold to grasp the outwardly flared upper skirt at a newly formed annular edge after the lower skirt 52 is removed as shown in the top part of FIG. 6. At the bottom of the lower skirt 52 is another inwardly-extending flange or undercut 54 which snaps under the outer edge of the bead 30 to form the lower lock. Gaps 53 may be molded into the undercut 54 at regular intervals to drain any overfill that might be forced out of the pail when the lid 14 is first applied. This prevents material from accumulating between the pail sidewall 16 near feature 30 and the lower lid skirt; a potentially odor-causing condition if the fill material is a food product subject to spoiling. The lower lock is, of course, removed in the opening procedure.

Further in accordance with the invention, indicia 58 comprising the combination of outwardly directed arrows and the legend “LIFT” are molded into the top surface of the deck 44 to indicate exactly where the locking segments 48 are located such that a user of the pail may apply a lifting force in this area after the removal of the lower skirt 52 has been achieved as hereinafter described. Other legends providing similar information may be used.

The lower skirt portion of the lid 14 comprises the depending skirt 52 terminating an undercut 54 which fits over and receives the bead 30 on the lower locking collar portion 18 of the pail sidewall 16 when the lid 14 is placed on pail 12 and firmly seated. However, a circumferentially extending weakened area provided by a notch 56 allows the lower portion of the skirt 52 to be torn away. A starter tab 60 is provided as shown in FIG. 1A in a cut-out area 62 for the purpose of facilitating the removal of the tear band formed by the skirt 52 so as to eliminate the lower lock 30, 54. The lower lock helps the container satisfy “drop test” requirements.

In operation, the pail 12 and lid 14 are typically injection molded at a suitable plant site. Once they are shipped to the customer, the container 10 is filled with product (not shown) and the lid 14 is seated on the container 12 such that the upper rim portion 26 of the container sidewall extends fully and contactingly into the channel 36. A pinch seal is provided by bump 27 if necessary, but a wedge seal is generally sufficient. There is a contact seal on both sides of the sidewall 16 and on the top of the rim. The upper lock 28, 50 snaps into place and the lower lock 30, 54 also snaps into place to securely hold the sealed lid 14 on the container 12. Similar containers 10 can be stacked and shipped in the product filled condition without fear of leakage or the ingestion of unwanted air into the interior of the container 10.

When the user is ready to gain access to the product, the starter tab 60 is broken away from the lid portion 52 and the lower skirt 52 is removed. This eliminates the lower lock 30, 54 and also provides evidence that the container 10 has been opened. Once the lower skirt 52 and the lower lock 30, 54, have been removed, the only lock holding the lid 14 to the pail 12 is the segmented upper lock 28, 50. This lock is strong enough to maintain the rim seal, but is relatively easily overcome without the use of tools by lifting the newly-revealed edge of the lid 14 immediately adjacent the indicia arrows 58. The plastic pail and lid combination is sufficiently flexible to permit the lid rim channel sidewall 38 below the lock 28 to be flexed outwardly and this overcomes the lock and permits the lid 14 to be removed from the pail 12. It also permits the lid 14 to be relocated and relocked onto the pail 12 using the three 120° spaced locks 28, 50. An audible “snap” occurs when the lid 14 is fully re-seated, telling the user that a good seal has been achieved. The snap comes from the undercut groove 56 receiving the bead 28.

Looking now to FIGS. 7-10, a second embodiment, generally similar to the first embodiment, will be described. The primary difference between the two embodiments is the minimization of the collar 18. This embodiment comprises a molded HDPE pail 60 and a molded HDPE lid 62 that fits onto the pail 60.

The pail 60 has an unflanged top rim 64 and an outwardly extending annular lock bead 66 about an inch below the rim, generally the same as the bead 28 in the embodiment of FIGS. 1-6. Moreover, the pail sidewall is outwardly enlarged near the top to define a neck and produces a shoulder 68 on the inside surface. Farther down the sidewall are outwardly and downwardly sloping sidewall rings 70 and 72, about ¾″ apart. The lower ring 72 is radially larger than upper ring 70. Ribs 75 support the lower ring 72. Tapered ribs 77 are molded between the upper ring 70 and the sidewall just below bead 66. Still farther down the pail sidewall is a ring 74 that is integral with the bottom of the bail ears 76.

The lid 62 has a recessed central deck 76, a raised peripheral structure 78 with an annular interior wall 80 that, when the lid is applied to the pail, fits tightly against the inner pail sidewall surface at the diametrically enlarged upper portion, with the bottom edge of the wall resting on the shoulder 68. An undercut groove 84 is spaced at the bottom of the receiving channel 82 to provide a receiving element for the sidewall bead 66. The configuration is such as to produce an audible, snap-fit function and the location is such as to provide the necessary upper lock only when the top pail rim is fully seated into the lid channel 82.

A tear groove 86 is located below the undercut groove 84 in an area where the lid skirt flares out, providing space between it and the pail sidewall. A starter tab shown in FIG. 7 is provided. Still farther below the tear groove 86 is another lock rim 88 that snaps under the ring 70 to provide a second lock, primarily to satisfy a drop test; i.e., to make sure the lid stays on if a filled container is dropped on a hard surface. When the lid skirt 90 is fully intact and seated, the bottom edge of the lid skirt is immediately above the larger ring 72, the small gap being such as to prevent entry by one's fingers for removal of the lid. As a result, the lower lid skirt 90 must be removed by tearing to open the sealed container. Once the lower skirt is removed, the newly formed edge is well above the ring 76 and fully spaced outwardly from the container sidewall so as to allow one's fingers to grasp the new lid edge and remove the lid from the pail 60. Further, the shortened skirt provides physical evidence that the pail has been opened.

In this embodiment, the distance from the top lock bead 66 to the top of the rim 64 is again such as to provide the snap fit described above, between the bead 66 and the undercut 84 in the lid skirt. Once again, a lower lock is provided between the lid skirt at 88 and the sloped ring 70 on the container sidewall below the shoulder 68. The tear groove 86 is located between the two lock rings.

As shown in FIG. 9, the length of the skirt 90 before removal of the lower portion is such as to place the skirt edge too close to the top of ring 92 to allow fingers to grasp the lid edge. Therefore, the lower portion of the skirt must be removed as shown in FIG. 10 before the pail 60 can be opened to access contents. Once the lower skirt is removed, the newly-formed edge 92 is spaced outwardly from the container sidewall and well above the ring 70, thus making it easy to grasp the edge for repeated removal. At the same time, the vertical tension produced by the dimensions of the lid groove 82 and the top of the container sidewall maintains a good seal and a tight hold between container and lid even though the lower lock has been removed. The container will not normally leak if tipped over after the lower lock 70, 88 has been removed.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.

Claims

1. A plastic container including an open top pail and a lid which sealingly fits on to the pail wherein the pail, the combination comprising: a pail with a sidewall and an unflanged top rim;a lid comprising a deck with a top surface surrounded by a peripheral portion defining an inverted U-shaped channel sized to sealingly receive the pail rim therein;the lid further comprising an outwardly flared skirt with a first annular interior detent groove, a second annular, interior detent groove, and an annular tear mechanism between the two detent grooves, the pail sidewall having formed on the exterior thereof a top annular ring below the rim and spaced relative to said rim to provide a snap fit into the first annular interior detent groove only when the rim is fully, sealingly seated into the channel; the sidewall having formed on the exterior thereof a bottom annular ring spaced below the top annular ring and located to lockingly enter the second detent groove only when the rim is fully and sealingly seated into said channel, said tear mechanism being located to expose, when operated, a newly-formed annular skirt edge that stands radially outwardly from the container sidewall and far enough above said lower annular ring to allow manual grasping of said newly-formed skirt edge for lid removal.

2. A plastic container as described in claim 1 wherein the top ring is segmented, the container further including indicia mold-formed on the top surface of the deck lid and indicating lifting locations for lid removal.

3. A plastic container as described in claim 1 wherein the lower lock ring is segmented.

4. A plastic container combination of the type described in claim 1 wherein the pail and lid are formed of high-density polyethylene.

5. A plastic container as described in claim 1 wherein the first detent groove and top ring are configured and sized to produce an audible snap upon being joined.