BACKGROUND OF THE INVENTION
The present invention pertains to closed plastic containers and, more particularly, to thermoformed containers having a snap-lock lid which, when pressed into locking engagement in a peripheral locking groove on the interior of the mouth of the container, virtually precludes manual removal without the use of a prying device or without permanent damage to the lid or the container.
Plastic containers made with the use of conventional thermoforming or vacuum forming techniques are widely used for various packaging functions. Flexible thin wall plastic containers are used to package wide varieties of consumer products because of their functionality, light weight and low cost. These containers are being used to an increasingly large extent to package expensive consumer products, including electronic devices and medical and dental products, as well as food products.
Such containers have long been made that utilize lids which are closed on the container with a snap-lock fit, which containers are also typically made so they can be opened by the consumer, usually by deflecting one or both pieces of the locking mechanism on the container and lid. Unfortunately, many of the containers are subject to surreptitious opening and theft of some or all of the contents by a shoplifter. On the other hand, if it is desired to provide a more secure closure in a snap-lock container and lid assembly, supplemental locking processes, such as heat sealing, solvent bonding, UV curable adhesives, radio frequency welding, ultrasonic welding and the like, are often used. However, this requires a completely separate additional step in the packaging process and is undesirable because of the added cost and the need for additional equipment and tooling.
Thus, there is a need for a plastic container and lid assembly that is easy to close with a snap-lock closure that locks the lid to the container with a tenacity that inhibits theft or pilferage of the contents without damaging, breaking or tearing the lid, container or both.
SUMMARY OF THE INVENTION
In accordance with the present invention, a secure locking container and lid assembly includes a resilient plastic container and a resilient plastic lid which, when joined with a snap-lock engagement, is virtually impossible to be manually removed without the use of a tool or without permanently damaging the container assembly and/or the product therein. The assembly includes a resilient container that has an open mouth defined by a generally vertical inner first wall portion, a generally horizontal second wall portion extending radially inwardly from a lower edge of the first wall portion, and a locking bead that extends peripherally around at least about 20% of the perimeter of the first wall portion and extends radially inwardly therefrom. The locking bead includes a generally planar lower surface that is spaced above the horizontal second wall portion that, together with the first wall portion, define a locking groove. A resilient lid is sized to fit within the locking groove and has a peripheral lip arrangement including an upper peripheral substantially planar free edge lip portion, a downwardly extending intermediate web portion, and a lower substantially planar surface portion that extends inwardly from a lower edge of the intermediate web portion and generally parallel to the upper lip portion. In response to vertical downward insertion of the lid into the mouth of the container, the lip arrangement overrides the locking bead and is inwardly deflected by contact therewith to move past the bead and to snap-lock into said locking groove, such that the lid is manually removable only by permanently damaging the lid and/or the container.
In a preferred embodiment, the locking bead includes an upper lead-in surface and the intermediate web portion on the lid assembly has a downwardly convergent surface to cooperate with the lead-in surface to facilitate lid deflection past the bead during insertion.
The assembly of the present invention may be used with containers of any shape from round to rectangular, but is particularly adaptable for use in assemblies in which a container and lid are generally rectangular with rounded corners, and wherein the locking bead comprises straight bead sections between and interrupted by the corners. In one embodiment, the beads include widened center portions between opposite bead ends to define deepened locking groove portions. The beads may be tapered along their lengths to extend inwardly from the opposite bead ends.
In one embodiment, the distance between the lip portion and the lower surface portion of the lip arrangement is just slightly greater than the distance between the second wall portion and the planar lower surface of the bead, whereby the lip arrangement fits snuggly in the locking groove.
In another embodiment, the distance between the lip portion and the lower surface portion of the lip arrangement is substantially less than the distance between the second wall portion and the planar lower surface of the bead, whereby a flexible snap-fit card may be inserted into the groove between the lower surface of the bead and the upper lip portion of the lip arrangement.
In an arrangement in which a more secure lock is desired, an adhesive is applied to one of said upper lip portion and said lower surface portion prior to insertion of the lid into the container. In a preferred embodiment, the adhesive comprises a UV curable adhesive, as well as the previously mentioned securing devices and methods.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the container forming a part of the present invention.
FIG. 2 is a perspective view of the lid forming a part of the present invention.
FIG. 3 is a perspective view of an assembled lid and container of FIGS. 1 and 2 shown formed of a transparent material.
FIG. 4 is an end elevation of the assembly shown in FIG. 3.
FIG. 5 is an end elevation of the lid shown in FIG. 2.
FIG. 6 is a vertical section through a container of FIG. 1.
FIG. 7 is an assembly, partially in section, of the lid and container of FIGS. 5 and 6.
FIG. 8 is a side elevation view of another embodiment of the lid.
FIG. 9 is a view similar to FIG. 7 showing the assembly of the container and the lid of FIG. 8.
FIG. 10 is a composite view of the lid shown in FIG. 5 and a separate flexible card used therewith.
FIG. 11 is a view similar to FIGS. 7 and 9 showing the lid and card of FIG. 10 inserted into the container.
FIG. 12 is a perspective view similar to FIG. 3 showing an alternate embodiment of the invention.
FIG. 13 is a perspective view of a container similar to that shown in FIG. 1 additionally showing a breakaway construction to facilitate removal of the lid.
FIG. 14 is an enlarged detail taken on line 14-14 of FIG. 13 and additionally showing the removable lid.
FIG. 15 is a perspective view of an assembled lid and container such as shown in FIG. 3 showing an embodiment providing a punch-out opening in the lid for access to the contents.
FIG. 16 is a perspective view of a container showing an alternate embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring initially to the assembly 10 of a lid 11 and container 12 shown separately in FIGS. 1 and 2 and assembled in FIGS. 3 and 4, the lid and container are both formed of a transparent or opaque plastic material such as PET, polystyrenes, polypropylene, HDPE, PVC or any other suitable plastic sheet material. The container 12 has a main body 13 for holding a suitable product of any of many diverse kinds. The container has an open mouth 14 that includes a locking bead 15 extending around all or most of the inner periphery of the mouth. The lid 11 includes a peripheral lip arrangement 16 sized to fit within the container mouth 14, but with an outer dimension large enough to overlie the locking bead 15. Due to the inherent resilience of the container 12 and particularly the lid 11, the lid may be pressed into the mouth 14 of the container causing the lip arrangement 16 to override the locking bead 15 and to snap and lock into a locking groove 17 in the mouth of the container below the locking bead 15.
Referring also to FIGS. 5-7, the open mouth 14 of the container 12 includes the locking bead 15 which has a generally planar lower surface 18. A generally vertical inner first wall portion 20 extends downwardly from the lower surface 18 of the locking bead and, at its lower edge, is joined by a generally horizontal second wall portion 21 that extends radially inwardly. The first wall portion preferably has a small positive draft of about 3°. The planar lower surface 18 of the locking bead 15, the first wall portion 20 and the second wall portion 21 together define the locking groove 17. In the embodiment shown, the groove 17 is substantially continuous around the inner periphery of the container mouth 14, except for interrupted portions at the rounded corners 22 of the container where there is no locking bead. Thus, in the embodiment shown, the locking bead 15 comprises four straight bead sections 23 along the linear edge portions of the rectangular container.
Each of the locking bead sections 23 extends inwardly from an upper container lip 24 that extends entirely around the mouth 14 of the container. Each bead section 23 has a downwardly sloping lead-in surface 25 which leads to a short vertical (or slightly drafted) wall section 26 that terminates at its lower edge where it joins the planar lower surface 18 of the locking bead.
In the embodiment shown in FIGS. 5 and 7, the peripheral lip arrangement 16 of the lid 11 includes a short outwardly extending lip portion 27 that extends at least along the straight linear edges of the rectangular lid, but may also extend continuously around the rounded lid corners 28. The inner edge of the lip portion 27 blends into a downwardly extending intermediate web portion 30 which preferably is provided with a small positive draft such that it tapers inwardly. The lower edge of the intermediate web portion 30 terminates at a lower substantially planar surface portion 31 which, in this embodiment, comprises the lowermost planar surface of the lid 11. The lid includes a rectangular raised center panel 32 formed integrally with the outer lip arrangement 16 and connected thereto by a generally vertical panel wall 33.
When the lid of FIG. 5 is pressed vertically downwardly into the open mouth 14 of the container 12 in FIG. 6, the lower outermost corner 34 of the lid, defined by the intersection of the intermediate web portion 30 and the lower planar surface portion 31, makes initial contact with the lead-in surface 25 of the locking bead sections 23. Sufficient downward force applied to the lid results in an inward deflection of the lid lip arrangement 16 and a concurrent outward deflection of the upper edge of the container 12, including the locking bead 15, until the outer lip portion 27 of the lid passes below the locking bead sections 23 causing the lid to snap into the locking groove 17 and be firmly locked therein, as shown in FIG. 7. The container and lid are dimensioned so that the edge of the lid lip portion 27 just engages or is very closely spaced from the first wall portion 20 of the locking groove where the wall portion joins the planar lower surface 18 of the locking bead 15. The first wall portion 20 is preferably formed with positive draft such that it slopes inwardly from the vertical. This causes the lid to seat tightly in the locking groove 17 at the top thereof as shown in FIG. 7.
It has been found that, once the lid 11 has been locked in the locking groove of the container 12, it is virtually impossible to remove the lid manually without the use of some type of prying device or without damaging the lid, the container or both. To remove the lid from the container, it is necessary to stretch the mouth 12 of the container enough to permit the locking bead 15 to clear the lip 27 of the lid. However, because of the tight fit of the lid in the locking groove 17 beneath the locking bead 15, a person is unable to insert his or her fingers between the two to exert a prying force sufficient to stretch the mouth 14 of the container over the lip of the lid. The use of a prying tool or similar device might be used to assist in manual removal of the lid, but such tactic will typically lead to damage of one or both components. The tenacity with which the lid is locked in the container and the difficulty presented when an attempt is made to manually remove it depend on a number of factors, including the length of the locking bead 15, the type and thickness or gauge of the plastic sheet material from which the lid and container are formed, the shape of the container, and the use of ribs or other structural features to enhance the overall rigidity of the components. With a light gauge and thus less rigid material, e.g. 0.015 inch (about 0.38 mm), a large total locking bead length of at least about 50% of the total perimeter should be used. If a heavy gauge plastic sheet is used, e.g. 0.040 inch (about 0.1 mm), a substantially shorter total locking bead length of at least about 15% may be used.
All of these considerations must also be tempered by the general consideration of how tenacious a locking container the customer requires. It may be, for example, that the customer desires a secure locking lid, but one that may still be removed without damaging the container, with an additional consideration of being able to replace the lid on the container. On the other hand, if the customer requirement is such that the container is not openable except by cutting, tearing or breaking the container and/or lid, then the factors such as higher gauge, inherently more rigid plastics, along with bead length must be considered. The locking bead should be uniformly distributed along the container edge. Also, the length of the container edge will affect the stiffness and thus the minimum length of the bead to provide adequate locking function. In the embodiment shown in FIG. 1, for example, the total length of the bead sections 23 comprises about 80% of the total perimeter length of about 27 inches of the container 12 made from a 0.040 inch polystyrene sheet. The gauge of the lid material is 0.030 to 0.035 inches (0.75 to 0.9 mm). The result is an extremely tenacious lock that cannot be opened without damage to the container and/or the lid. By adjusting the various features identified above, a secure locking container may be provided with total locking bead length of at least about 15% of the total perimeter length of the container. In addition, although a lid 11 locked onto a container 12 is typically susceptible to substantial bending and distortion to assist unlocking and removal when the container is empty, the product which is packaged in and substantially fills the container inhibits such bending and distortion, thereby further inhibiting unlocking and removal of the lid.
In FIGS. 8 and 9, there is shown a modified lid 35 and its secure locking engagement in a container 12 identical to the container shown in the previously described embodiment. The FIG. 8 lid 35 is identical to the lid 11 of the previously described embodiment, except that it has a substantially greater depth or thickness created by a longer intermediate web portion 36 that joins an upper peripheral lip portion 37 and a lower planar surface portion 38. The lid 35 is inserted into the container 12 and locked in the container locking groove 17 in the same manner previously described. However, once locked in the groove 17, the lid 35 is captured snuggly therein with the upper lip portion 37 engaging the planar lower surface 18 of the locking bead 15, and the lower planar surface portion 38 engaging the horizontal second wall portion 21 at the bottom of the locking groove.
The FIG. 8 lid embodiment is particularly suitable where it is desirable to provide an even more secure locking of the lid 35 in the container 12 by providing an adhesive bond therebetween. Although several different means could be utilized to provide a supplemental adhesive bond between contacting surfaces of the lid and the container, such as bonding solvents, heat sealing, ultrasonic and radio frequency welding, or other applied adhesives, one particularly attractive method is to provide a UV curable adhesive between the top surface of the lid lip portion 37 and the planar lower surface 18 of the locking bead, or between the underside of the lower planar surface portion 38 of the lid and the top surface of the second wall portion 21 of the container. Preferably, the application of a UV curable adhesive, to either the upper surface of the lip portion 37 or the lower face of the lower planar surface portion 38 before the lid is installed, permits the supplemental adhesive lock to be effected simply by running the closed container assembly through a UV curing station.
Referring now to FIGS. 10 and 11, there is shown an assembly in which a lid 11 of FIG. 5 and a container 12 of FIG. 6 are locked together with a flexible card 40 that is placed over the lid 11 and also locked in the locking groove 17. The card 40 is sized and shaped to fit snuggly in the locking groove 17, but must be flexible enough to be bent slightly during the insertion process. A thin sheet of paperboard is one suitable material and provides several additional benefits. The card may be provided with printed or decorative indicia on either or both faces. The card also provides added security by presenting a completely smooth outer surface inhibiting any kind of gripping by fingers. The flexible card may also be used to provide a spacer or shimming function to press the lower planar surface portion 31 of the lid into contact with horizontal wall portion 21 of the locking groove where an adhesive is applied to the surface portion 31 to provide a supplemental locking feature.
Referring to FIG. 12, there is shown a modified container 41 which is identical to the previously described container 12, except that the container 41 has modified locking bead sections 42. The modified bead sections extend inwardly farther than the bead sections 23 previously described, thereby extending the depth of the locking groove 43 under the bead sections. Each modified bead section 42 curves outwardly from opposite ends along a smooth curve to a widened center portion 44. Each modified bead section 42 includes a crescent-shaped lead-in surface 25 that tapers downwardly and inwardly and is joined by a curved vertical wall section 46. As in the previously described embodiments, a planar lower surface 47 of each locking bead section 42 defines the upper surface of the locking groove 43. The use of the extended locking bead sections 42 of this embodiment requires somewhat more flexibility of the lid and/or the container, but once the lid is installed, modified locking bead sections provide substantial additional security against undesirable opening.
In the locking beads described for each of the preceding embodiments, each locking bead section 23 or 42 extends continuously along substantially the entire length of each straight wall section of the rectangular container. By providing continuous length bead sections, the resultant beam effect enhances considerably the stiffness and rigidity of the mouth of the container, thereby also enhancing the security of the locking feature. If shorter locking bead sections or sections that are interrupted along the length so as not to be continuous are used, there will be an inherent sacrifice in rigidity for which compensation might be provided by, for example, utilizing heavier gauge material. In general, it is believed that the secure locking feature of the present invention may be utilized in a wide variety of shapes and sizes of thermoformed containers made from web stock ranging widely in thickness. As indicated previously, suitable plastic materials may include polystyrenes, PET, PETG, RPET, polypropylene, HDPE and PVC. PET, PETG and PVC are harder and stiffer than the other plastics listed. Consideration of the hardness and stiffness of the material is also important in meeting the specific customer requirement for a secure locking container, as discussed above.
As shown in FIG. 1, the upper container lip 24 on one edge of the container 12 may comprise a lip 50 which is provided with hanger holes 51 for point of sale storage of and display purposes. It may also be desirable, when packaging products that are not all consumed or used at once, to provide the flat center panel 32 of the lid 11 with a die cut perforated line to permit partial opening and reclosing of the container to store unused product. It should also be noted that the flat construction of the lid 11, characterized by the flat center panel 32, is not a requirement of the invention. Rather, the lid may be provided with some depth, like the container 12, to enclose and hold product.
The additional embodiments of the invention shown in FIGS. 13-15 utilize container and lid constructions that may be identical to those shown in FIGS. 1, 3 and 4 and, therefore, similar features are identically numbered. The container 12 shown in FIG. 13 is provided along one upper edge, between adjacent corners 22 with edge perforations 52. Each perforation 52 extends across the surface of the upper container lip 24 and down along the first wall portion 20 to the junction between the first wall portion 20 and the second wall portion 21. Because the locking bead sections 23 terminate short of the corners 22, the perforation 52 does not extend into the bead section.
The perforations provide weakened sections such that the purchaser may grasp the upper container lip 24 and bead section 23, break it away from the remainder of the container, and turn it downwardly generally around a line defining the transition between the first wall portion 20 and the second wall portion 21, all as shown in FIG. 14. With this portion of the upper container lip 24 out of the way, the lid 10 can be slid along the locking grooves 17 to partially or completely open the container 12.
The foregoing feature permits more ready access to a closed container of the present invention than would be possible without indiscriminate cutting or attempting to overcome the primary locking feature. The lid 11 could, of course, be replaced by simply reversing the procedure.
In FIG. 15, there is shown an embodiment of the FIG. 3 container and lid in which the raised center panel 32 of the lid 11 is provided with a perforated panel 53 to facilitate access to discrete individual objects that are enclosed in the container. The perforated panel 53 is defined by a perf line 54 that preferably includes a scored end 55. The panel 53 can be punched inwardly or pulled outwardly to free it from the center panel 32, enabling it to be lifted around the scored end 55. After an object is removed by the purchaser, the panel 53 can be pushed back into its original position in the lid panel 32 to reclose the container. The access panel could alternately be provided in an opposite bottom wall of the container 12.
In FIG. 16, there is shown an alternate embodiment of a secure locking container 60 of the present invention. This container has a square shape similar to the previously described embodiments, but if made of a smaller size, the total length of the locking bead arrangement may be reduced considerably. The shortened length of the container edges adds to the stiffness of the container and the corresponding ability to reduce the effective length of the locking beads. For example, if the container 60 of FIG. 16 is made approximately 5 inches (about 125 mm) square, and of a RPET material having a gauge of 0.035 inches (about 0.1 mm), pairs of shortened locking beads 56 along each edge of the container mouth will provide a satisfactory locking function. The lid used with this container may be made from the same gauge material, but typically the lid is made of smaller gauge material, e.g. 0.030 inch (0.75 mm). In this embodiment, each of the locking beads 56 is about ⅜ inch (about 10 mm) long, the total locking bead length comprising about 15% of the periphery of the container.
Patent Application
20060060578
