Container Lid

Abstract

A stackable lid or closure for use with containers having a complementary open mouth rim portion, the lid having a configuration which insures smooth and instant release during coin-feeding of the bottom lid from a vertical stack thereof, the same configuration providing a stack of lids which will resist displacement or jamming of the lids in the stack.

Description

This invention relates generally to improvements in a closure or lid for containers and more particularly relates to a lid adapted for attachment to and removal from a container of the kind commonly used to contain cold or hot, liquid or solid food products.

One most important function of the lids disclosed herein is to cover, seal, and permit removal from a complementary container. The sealing function becomes especially important when used in connection with perishable items such as food, and the configuration of the present lid is especially directed toward forming a tight seal in conjunction with the container.

An additional requirement for the lid is imposed where automatic feeding or dispensing of the lids is contemplated. Automatic dispensing apparatus may be used in dispensing machines to discharge the lids and, likewise, the lids may be dispensed by equipment used to cap food containers or the like. With use in such equipment it is customary, due to space requirements, to arrange the lids in a vertical stack, from which they are removed for capping the open mouth containers. Individual lids may then be removed from the bottom of the stack in synchronous relationship with the container filling apparatus for movement to a container lid assembly station where the capping operation takes place. The term coin-feeding is generally used to describe the feeding operation where the lid is made to slide out from the bottom of the vertical stack in a generally horizontal direction. To facilitate this sliding movement, it is of great importance that the lids be smoothly and instantly released from the bottom of the stack. It is also desirable to avoid tilting the stack, which might cause displacement of the stacked lids relative to one another, causing subsequent lid feeding problems. The lids, according to the present invention, are thus provided with stacking means which insure both a smooth and instant release of the bottom lid when coin fed from the stack while minimizing tilting of the lid stack. The stacking means are such in fact that will at all times aid in maintaining each lid in a stack in its proper position.

After the containers are filled with the food product, for example, they are automatically capped by machinery which locates the containers with respect to the lids and press fits the lids on the containers. The lid configuration disclosed herein is such that it aids in locating and guiding the lids over the rim portion of the container during this operation and whenever replacing the lids on the container.

Still another requirement, which is met by the lid configuration herein disclosed, is that of providing lids which will resist undesirable nesting or jamming when a stack of the lids is dropped in shipping, for example, or a heavy load is placed upon a stack of lids inadvertently during shipping or storage. If the lids are jammed together, they will not only fail to feed properly but, due to their construction of rather thin and preferably plastic material, they may become so distorted that they will no longer properly seal the container. To prevent such jamming and to fulfill the previously mentioned requirements, the lid of the present invention is provided with the novel structural arrangement to be described.

Accordingly, it is an object of the present invention to provide a container lid or closure which incorporates several advantageous features in a simple structure which serves a multitude of purposes.

Another object of the invention is to provide a container lid having means for forming a tight seal in conjunction with the container.

A further object of the invention is to provide a container lid with stacking means which insures a smooth and instant release of the bottom lid when coin fed from a stack of lids while minimizing tilting of the stack.

Still a further object of the invention is to provide a container lid having stacking means which will at all times aid in maintaining each lid in a stack in its proper position.

Another object of the invention is to provide a container lid having a configuration which aids in locating and guiding the lids over the rim portion of the container when attaching the lids thereto.

A further object of the invention is to provide a container lid having a configuration which prevents jamming of the lids during shipping or storage.

Still a further object is to provide a container lid which can be easily and economically made by known molding or manufacturing techniques.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

To accomplish these and other objects, the lid of the present invention is provided with a bottom wall lying substantially in a plane and adapted to cover the mouth of a container, a sidewall extending upward from the bottom wall, a horizontal flange joined to the top of the sidewall, and a depending skirt secured to the outer edge of the flange. A bead is formed at the junction of the bottom and side walls, which is adapted to be received in a channel provided in a complementary container. The skirt is made of such a length that its extreme lower end lies normally in the plane of the bottom wall. The skirt has an inwardly extending groove spaced from the lower end, and the bottom portion of the skirt, beginning at the groove and extending to the extreme lower end, is adapted to support the lid upon a like lid disposed beneath it when a plurality of the lids are stacked for shipping or for use in automatic capping equipment. The bottom portion of the skirt is disposed at such an angle relative to the lid axis that it aids in locating and guiding the lids over the rim portion of a complementary container as well as generally maintaining each lid in its proper position in a stack.

The groove in the lid skirt results in a stiffer skirt which resists deformation when engaged by a coin-feeding element of the capping equipment. The inwardly extending portion of the skirt forming the groove is also adapted to snap over the rolled rim of the container with which it is used, to prevent inadvertent removal of the lid from the container. When arranged in a stack, the bead of each lid also engages the lid beneath it, thus providing further support for each lid in the stack.

Because the extreme lower end of the lid skirt lies substantially in the plane of the bottom wall, it can be seen that during a coin-feeding operation wherein the bottom lid is moved horizontally from the stack, there will be no interruption of the sliding movement due to interlocking or nesting. This lower end of the lid skirt, on the lid above the lid being fed, will tend to aid in supporting the entire stack above during the feeding action, minimizing tilting of the stack.

To resist undesirable nesting or jamming of the lids due to dropping of a stack of lids or a weight placed on the lids during storage or shipping, for example, the top portion of the sidewall of each lid is formed into a frustoconical ledge which supports the bead of the lid above in a stack of such lids. The angle of the ledge relative to the axis of the lid is such as to provide the optimum amount of support for the lids in the stack to resist fairly heavy static loads, while utilizing the maximum resilience due to the ledge configuration to resist shock such as experienced in dropping of the stack.

The features of this invention along with its incidental advantages will be better understood and appreciated from the following detailed description of several embodiments thereof, selected for purposes of illustration and shown in the accompanying drawing in which:

FIG. 1 is a perspective view of the novel container lid or closure member of the present invention;

FIG. 2 is a fragmentary side elevational view, partially in section of the container lid shown in FIG. 1 assembled to a complementary container;

FIG. 3 is a sectional view of a plurality of stacked lids, showing the manner in which the lids are coin-fed by sliding removal of the lowermost lid from the remainder of the stacked lids;

FIG. 4 is an enlarged fragmentary cross-sectional view of a pair of lids identical to that in FIGS. 1, 2, and 3, showing the manner in which the lids resist undesirable nesting or jamming;

FIG. 5 is an enlarged fragmentary cross-sectional view, similar to FIG. 4 but taken on lines 5--5 of FIG. 6 of a modified form of container lid;

FIG. 6 is a top plan view of the lid as illustrated in FIG. 5.

Referring to the drawing, and first to FIGS. 1 and 2, there is shown a lid or closure, member 10, which forms a package in conjunction with container 12, which for purposes of illustration may be considered as especially designed for a food product, for example, yogurt. Both the lid 10 and container 12 are preferably made from thermoplastic materials such as polystyrene, polyethylene, and other similar plastic materials. The configurations of the lid and container are such that they may be easily and economically formed by conventional thermoforming techniques, as one-piece seamless articles of a thin-wall nature, so as to compete with their counterparts made of paper. It should be understood that other materials may also be employed either separately or combined in some manner with thermoplastic materials to form the lids described herein.

The lid 10 is adapted to be positioned over the open mouth of the container 12, having a complementary configured rim portion 14 as shown in FIG. 2. Located in the vicinity of rim portion 14 in the sidewall 16 of the container is an inwardly facing groove 18 which serves as a means for sealing the container in conjunction with the lid 10 as set forth in detail hereinafter.

For covering the container the lid 10 is provided with a horizontally extending generally planer bottom wall 20 which overlies the open mouth of the container 12 adjacent the rim portion 14 thereof. Joined to the periphery of the bottom wall is an annular side wall 22 which projects a suitable distance upward in order to accommodate the rim portion 14 of the container. At the junction of the bottom wall 10 and sidewall 22 a bead 24 is formed which serves a twofold purpose. When associated with the container 12, the bead 24 is designed to engage the groove 18 in the container sidewall. The relative diameters and configuration of the bead 24 and the container groove 18 are designed to provide a tight-fitting engagement between the lid and container when assembled to each other. This coaction will establish a seal between the container and lid, so as to protect the contents of the container from entry of air and foreign particles, or the like, and also prevent spillage if the container is tipped over. The second function of the bead 24 is that it serves as a stacking means in a manner to be described.

Referring again to FIGS. 1 and 2, the sidewall 22 includes a bend 26 therein dividing it into a lower portion 28, with the horizontal span thereof being less than the span of bead 20, and a top portion 30 which extends upwardly and outwardly from bend 26. The horizontal span at the upper end of top portion 30 of the sidewall is greater than the span of the bead in order to perform an important function when the lids are stacked upon one another, which will be elaborated upon later in this description.

An outwardly extending flange 32 is joined to the extreme top end of the sidewall, and a depending annular skirt 34 is secured to the outer edge of the flange. The skirt has an inwardly extending groove 36 formed therein and a bottom portion 38, beginning at the groove 36 and extending downward and outward for a distance such that the extreme lower end 40 of the skirt lies substantially in a horizontal plane which includes the bottom wall 20 of the lid. When associated with the container 12, the inwardly extending portion 42 of the skirt forming a section of the groove 36 is designed to engage the curled lip rim portion 14 on the underside thereof if, for example, the skirt is caught on some object and the lid is displaced upwardly. This will prevent inadvertent removal of the lid and breaking of the seal with the container. The skirt 34, being made of flexible thermoplastic material, will flex radially outwardly to allow the portion 42 to "snap" over the curled rim portion 14.

The stacking and manner of coin-feeding the lids is illustrated in FIG. 3 of the drawing. It will be noted that when the lids are stacked one upon the other, the bead 24 contacts the top portion 30 of the side wall 22 of the next lower lid, just as the bottom portion 38 of the skirt 34 engages the outer edge of the flange 32. Thus, both the bead 24 and portion 38 of the skirt support each lid on the lid below, providing two continuous circular lines of contact which result in a very stable stack with each lid firmly seated on the lid below. As shown in FIG. 3, during the feeding operation the bottom lid is moved horizontally from the stack in the direction of the arrow, for example, by an arm 44 or the like, which engages the skirt 34 of the lowermost lid. The upper portion 45 of the skirt 34, as shown in FIG. 2, extends straight downwardly for at least half the length of the skirt between flange 32 and the continuous groove 36 to provide an uninterrupted surface for engagement by the feeding apparatus.

The groove 36 in the skirt will act as a stiffening rib, resisting deformation of the skirt when it is engaged by arm 44. Because the extreme lower end 40 of the lid skirt 34 lies substantially in the plane of the bottom wall 20, it can be seen that during the coin-feeding operation wherein the bottom lid is horizontally moved, the two lines of contact between the lids will release simultaneously, so there will be no interruption of the sliding movement. The lower end 40 of the lid directly above that lid being fed will aid in supporting the entire stack above during the feeding action, minimizing tilting of the stack and possible displacement of some of the lids from their proper stacked position.

FIG. 4 illustrates the special stacking features of the invention. In particular, the top portion 30 of the side wall 22 of each lid is formed into a frustoconical ledge which supports the bead 24 of the lid above. The ledge is disposed at an angle a relative to the axis 46 (see FIG. 2) of the lid of between 35.degree. and 55.degree.. The preferable range of angle is between 40.degree. and 50.degree. and most desirably about 45.degree.. This 45.degree. angle of the ledge provides the optimum amount of support for the lids in the stack to resist fairly heavy static loads, such as a weight placed thereon during storage, while utilizing the maximum resilience due to the ledge configuration to resist shock such as experienced in dropping of the stack. The width of the ledge designated W in FIG. 2 is greater than one-third the overall length W + D (FIG. 2) of sidewall 22 to provide a substantially wide supporting surface to prevent a bead 20 supported thereby in a stack of lids to be forced past the bend 26 in the sidewall causing jamming of the lids.

The bottom portion 38 of the skirt 34 also resists loading by tending to flatten out, as shown by dotted lines in FIG. 4, when under load, which increases its ability to withstand such loads without damaging deformation. Thus the operation of both the frustoconical supporting ledge and the bottom portion of the skirt resist jamming or undesirable nesting of the lids. As shown in dotted lines in FIG. 4, the bead 24 of the lid being supported will tend to slide partly down the frustoconical ledge formed by portion 30 as the portion 38 of the skirt flattens out under load; but when the load is removed, due to the resiliency in the plastic lid material the lids will return to their normal position, as shown in solid lines.

The bottom portion 38 of the skirt is disposed at an angle b relative to the lid axis 46 (see FIG. 2). It is an important aspect of the invention that angle b should be approximately 30.degree.. This will provide the proper support for the lids in the stack to resist loads while maintaining resilience in the stack. This angular configuration also aids in locating and guiding the lids over the rim portion 14 of the container when the lid is attached thereto. As shown in FIG. 2, the lip of the container is curled or rolled and portion 38 of the lid, when contacting this lip, has just the proper angular configuration to first locate the lid around the circumference of the rim and then guide the skirt 34 in its movement over the container lip.

The approximate 30.degree. angular disposition of bottom portion 38 of the lid skirt and the 45.degree. angular disposition of the top portion 30 of the lid sidewall also aid in maintaining each lid in a stack of lids in its proper position. As shown in FIG. 3 the lids are "stacked on two angles," the bead 24 resting on the angular portion 30 and the angular bottom portion 38 resting on the lid below. Thus, if any force tends to displace a lid in any direction, one or the other angular portions tend to cam or draw the lid back into its properly stacked position.

To withstand even heavier loads, a further embodiment of the invention, as shown in FIGS. 5 and 6, provides means for positively limiting the sliding action of the bead 24' on the frustoconical ledge of the lid below. The limiting means comprise a plurality of flats or lugs 48 spaced around the circumference of the sidewall 22' of each lid as shown in FIG. 6. In cross section as shown in FIG. 5, these lugs 48 include a flat portion 50 which extends horizontally from the extreme lower end of the frustoconical ledge formed by the top portion 30' of the sidewall 18. As the bead 24' slides down the ledge under load as shown in dotted lines in FIG. 5, the portion 50 acts as a positive stop preventing any further movement. It is obvious that only a very heavy load not ordinarily encountered could force the bead 24' to slip past portion 50, causing jamming of the lids. The lower portion 28' of the side wall 18 has a slight taper as shown in FIG. 5, which aids in removal of the lids from the mold used to form them. The taper on portion 28' meets flat portion 50.

The terms "inwardly" and "outwardly" refer to the directions toward and away, respectively, from the axial center of the lid. The terms "downward" and "upward" refer to those directions relative to the lid and container as depicted in the drawing.

The angle a of the frustoconical supporting ledge on the lid and angle b of the bottom portion of the skirt have been described herein relative to the vertical or symmetrical axis 46 of the lid as shown in FIG. 2 of the drawing.

It should be apparent that the lid as disclosed herein is such that the configuration of each element, and in particular the sidewall and skirt, cooperate with one another both structurally and functionally to achieve a number of important advantages not heretofore available. Each element is interrelated with one another, and it is this interrelationship which allows the lid to accomplish the many objects of the invention.

Claims

I claim:

1. A stackable lid for a container, said container including an inwardly facing groove near a rim portion thereof, said lid comprising:

a bottom wall lying substantially in a plane;

a sidewall joined to the periphery of said bottom wall;

a bead for engaging the groove on said container formed at the junction of said side and bottom walls and adapted to support the lid upon the sidewall of a like lid disposed beneath it in a stack of such lids;

said sidewall extending upward from said bead with its horizontal span at its bottom being less than the horizontal span of said bead and with its horizontal span at the top thereof being greater than the horizontal span of said bead, said sidewall being positioned and configured so that the bead of a like lid disposed above said lid in a stack of such lids is normally supported on said sidewall near the top edge thereof;

an outwardly extending flange joined to the top of the sidewall;

a depending skirt secured to the outer edge of said flange, said skirt being of such length that the extreme lower end thereof normally lies substantially in the plane of the bottom wall;

an inwardly extending continuous groove on the skirt spaced from said extreme lower end thereof;

the bottom portion of said skirt beginning at said groove and extending to said extreme lower end thereof being downwardly and outwardly flared and adapted to support the lid upon a like lid disposed beneath it in a stack of such lids.

2. A lid according to claim 1 in which said sidewall of said lid has upper and lower portions which are joined at a bend in said sidewall, said upper portion of said sidewall extending upwardly and outwardly from said bend and being positioned and configured for supporting the bead of a like lid disposed above it in a stack of such lids.

3. A lid according to claim 2 wherein said upper portion of said sidewall comprises a frustoconical ledge extending continuously upwardly and outwardly from said bend at an angle of between 35.degree. and 55.degree. relative to the vertical axis of said lid.

4. A lid according to claim 2 wherein said upper portion of said sidewall comprises a frustoconical ledge extending continuously upwardly and outwardly from said bend at an angle of approximately 45.degree. relative to the vertical axis of said lid.

5. A lid according to claim 4 wherein said bottom portion of said skirt extends continuously downwardly and outwardly at an angle of approximately 30.degree. relative to the vertical axis of said lid.

6. A lid according to claim 4 wherein the width of said frustoconical ledge is greater than one-third the length of the sidewall to provide a substantially wide supporting surface to prevent a bead supported thereby in a stack of lids to be forced past said bend in said sidewall causing jamming of said lids.

7. A lid according to claim 6 wherein said skirt extends straight downwardly for at least half the length of the skirt between said flange and said continuous groove to provide an uninterrupted surface for engagement by lid feeding apparatus.

8. A lid according to claim 2 wherein said upper portion of said sidewall comprises a frustoconical ledge extending continuously upwardly and outwardly from said bend at an angle of between 40.degree. and 50.degree. relative to the vertical axis of said lid.

9. A lid according to claim 1 in which said sidewall of said lid has upper and lower portions which are joined at a bend in said sidewall, said upper portion of said sidewall extending upwardly and outwardly from said bend except in selected sections thereof and being positioned and configured for supporting the bead of a like lid disposed above it in a stack of such lids.

10. A lid according to claim 9 wherein said upper portion of said sidewall immediately adjacent said bend in said selected sections around the circumference of said lid extends only inwardly in a horizontal direction for a limited distance to provide a supporting shelf to prevent the bead of a like lid normally supported by said top portion of said sidewall in a stack of such lids from being forced past said bend causing jamming of said lids.

11. A lid according to claim 10 wherein said lower portion of said sidewall in said selected sections around the circumference of said lid extends continuously upwardly and inwardly until it terminates at said bend to aid in removal of said lid from its forming mold by requiring a camming surface in said mold to coact with said bead to continuously reduce the diameter of said bead until it passes the bend forming portion of said mold upon removal of said lid from said mold.