Abstract:
A lightweight overcap for a cylindrical container that requires substantially less material. The material savings is realized by the use of thinner walls and intermittent closure, nesting and stacking structures.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to overcaps for containers, and more particularly to an overcap for beaded, stackable containers that is significantly lighter than conventional overcaps. 
     2. Description of the Related Art 
     Plastic overcaps, typically made of low density polyethylene (LDPE), are commonly used to reclose the open end of cylindrical containers used for holding items such as snacks, drink mixes, coffee and shortening. Such overcaps protect the contents of the container from contamination but do not provide an oxygen barrier and are not airtight. 
     Overcaps generally have a planar covering portion and a sidewall extending downward from the periphery of the covering portion. A vertex juts inwardly from the interior of the sidewall to engage the underside of the lip of a container. To open the container, the user lifts up and out on the lower edge of the sidewall, thereby disengaging the vertex from the lip. 
     Overcaps sometimes have a nesting ring projecting upwardly from the planar covering portion of the overcap near its circumference and a depressed ledge extending outward from the nesting ring. The nesting ring and ledge cooperate to hold a second overcap placed on top so that a number of overcaps can be held in stacked fashion. The stack of overcaps can be picked up by machine and placed in a shipping box. 
     Some conventional overcaps also have a stacking ring or lug projecting upwardly from the planar covering portion of the overcap, concentric with the nesting ring but having a smaller diameter. The stacking lug seats within the recessed end of the bottom of a second container to maintain the second container in stacked alignment with the first container. 
     While such conventional overcaps are suited for their particular purpose, there nevertheless is a need for an overcap that performs the same functions but uses less material. The present invention fulfills this need by providing an overcap having an intermittent nesting ring and stacking lug, intermittent vertex, and thinner walls than conventional overcaps. 
     Therefore it is an object of the present invention to provide an overcap for stackable containers that is lighter weight and requires significantly less material than conventional overcaps. 
     Another object of the invention is to provide a lightweight overcap that retains the sturdy feel of heavier overcaps. 
     Further and additional objects will appear from the description and accompanying drawings. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is an overcap for a beaded cylindrical container that is significantly lighter than conventional overcaps. The lightweight overcap comprises a substantially planar covering portion, a sidewall portion, intermittent locking detents for securing the overcap to the container, intermittent nesting segments for nesting a second overcap on top, and intermittent stacking lugs to seat the overcap within the recessed end of a second container stacked on top of the assembled overcap and container. 
     The covering portion has a circular flat central portion and a raised annular portion extending outwardly therefrom. The periphery of the annular portion forms a recessed nesting ledge for receiving a second overcap. The sidewall extends downwardly from the periphery of the annular portion. 
     The locking detents are evenly disposed about the inner surface of the sidewall and extend inwardly therefrom. The detents are adapted to fit under the beaded top of the container to secure the overcap to the container. 
     The intermittent nesting segments are longitudinally aligned and evenly disposed about the upper surface of the annular portion. The nesting segments are adapted to form a frictional fit with the inside of a similarly configured overcap to facilitate nesting of the overcaps during shipping and storage. 
     The intermittent stacking lugs are longitudinally aligned and evenly disposed about the upper surface of the annular portion, and are adapted to fit within the bottom of a similarly configured container to facilitate stacking of multiple containers with overcaps. 
     Preferably, the nesting segments and stacking lugs are staggered around the annular portion, meaning a line normal to the arc of the annular portion may intersect a nesting segment or a stacking lug, but not both. The detents preferably are aligned with the nesting segments. 
     In the preferred embodiment, the covering portion is about 0.013 inches thick and the sidewall is about 0.019 inches thick. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of one embodiment of a lightweight overcap made according to the present invention. 
     FIG. 2 is a cross-sectional view of the overcap of FIG. 1 taken along line  2 — 2 . 
     FIG. 3 is a bottom plan view of the overcap of FIG.  1 . 
     FIG. 4 is an enlarged, fragmentary cross-sectional view of the overcap of FIG. 1, taken along line  4 — 4 . 
     FIG. 5 is an enlarged, fragmentary cross sectional view of the overcap of FIG. 1, taken along line  5 — 5 . 
     FIG. 6 is a greatly enlarged view of a portion of FIG. 5, showing the intermittent nesting ring in greater detail. 
     FIG. 7 is an enlarged, fragmentary cross-sectional view of an overcap according to FIG.  1  and the bottom rim of a container positioned on top of the overcap. 
     FIG. 8 is an enlarged, fragmentary cross-sectional view of two lightweight overcaps made according to the present invention and nested together. 
     FIG. 9 is an enlarged, fragmentary cross-sectional view of a lightweight overcap shown covering the open end of a conventional container. 
     FIG. 10 is an enlarged cutaway perspective view of the overcap of FIG.  1 . 
     FIG. 11 is a top perspective view of an alternative embodiment of a lightweight overcap made according to the present invention with an integrally formed reinforcing stepped portion. 
     FIG. 12 is a bottom perspective view of an alternative embodiment of a lightweight overcap made according to the present invention with integrally formed reinforcing ribs. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is a lightweight overcap for use with beaded, stackable containers used for holding items such as snacks, drink mixes, coffee and shortening. Referring to FIGS. 1 and 2, the overcap  10  comprises a substantially planar top covering portion  12  and a sidewall  14 . As best shown in FIG. 4, a vertex or detent  16  extends inwardly from the interior of the sidewall  14  to engage the beaded top  72  of a container  70  (FIG.  9 ). 
     As shown in FIGS. 1,  8  and  10 , the top covering portion  12  comprises a circular flat central portion  18 , an angled wall portion  20  extending upwardly and outwardly from the central portion  18 , a raised annular portion  22  extending outwardly therefrom, and a slightly recessed nesting ledge  24  extending circumferentially around the raised annular portion  22 . The preferred angle defined by the central portion  18  and the flared wall portion  20  is about sixty degrees. The sidewall  14  extends downwardly from the periphery of the top portion  12 . 
     As shown in FIGS. 2 and 3, the vertex  16  is interrupted, i.e., not continuous. Each segment  16  of the vertex may be referred to as a detent, each detent  16  being similar to a tab that engages the underside of the container bead. Preferably, the detents  16  are evenly disposed about the inner surface of the sidewall  14  and extend inwardly therefrom. 
     Disposed around the top surface of the annular portion  22  is a nesting ring  28 . The nesting ring  28  is also segmented. The intermittent nesting segments  28  are arcuately shaped and evenly disposed about the upper surface of the raised annular portion  22 , and are configured to form a frictional fit with the inside surface of the sidewall of a similarly configured overcap to facilitate nesting of the overcaps during shipping and storage (FIG.  8 ). When nested, the ledge  24  of the overcap  10  receives the bottom edge  15  of a second identical overcap. 
     As best shown in FIG. 6, each nesting segment  28  comprises an inwardly angled inner wall  30 , a top surface  32 , a vertical outer wall  34  and a beveled edge  36  extending between the top surface  32  and the vertical outer wall  34 . The beveled edge  36  facilitates nesting of multiple overcaps by guiding the sidewall  14  of one overcap onto the nesting ledge  24  of another overcap. 
     As shown in FIGS. 1,  7  and  10 , a stacking ring  38  is also disposed around the top surface of the annular portion. The stacking ring  38  is also intermittent, forming multiple intermittent arcuately shaped stacking lugs  38  longitudinally aligned and evenly disposed about the upper surface of the annular portion  22 . The stacking lugs  38  are adapted to fit within the bottom edge  74  of a similarly configured container  70  to facilitate stacking of multiple containers with overcaps. 
     As best shown in FIGS. 5 and 10, the stacking lugs  38  comprise an inwardly angled inner wall  40 , a top surface  42  and an outwardly angled outer wall  44 . Preferably, the inner wall  40  is a continuation of the covering portion flared wall  20 . The preferred vertical dimension of the stacking lugs  38 , measured from the top surface of the annular portion  22 , is 0.013 inches. 
     In the preferred embodiment shown in FIGS. 1-10, the nesting ring segments  28  and the stacking lugs  38  are staggered about the annular portion, meaning a line normal to the arc of the annular portion may intersect a nesting segment or a stacking lug, but not both. The detents  16  preferably are coextensive with the nesting ring segments  28 . Thus, line  4 — 4  of FIG. 1 passes through a stacking lug  38  but not a detent  16  or a nesting segment  28 , while line  5 — 5  passes through a detent  16  and a nesting segment  28  but not a stacking lug  38 . 
     Conventional overcaps come in many shapes and sizes. Usually the sidewall thickness ranges from about 0.026 inches to 0.036 inches and the top wall thickness ranges from about 0.020 inches to 0.046 inches. By contrast, the sidewalls  14  of the present invention are a mere 0.019 inches thick and the central covering portion  18  is only 0.013 inches thick, resulting in a savings of material, although these dimensions can be varied according to the application. Additional savings of material is realized by making the vertex, nesting ring and stacking lug intermittent. The present invention decreases up to 30% the amount of material required for a typical overcap, yet the savings in material is intended to be transparent to the consumer. 
     Reinforcing structures may be integrally formed into the overcap central portion  18  to increase the rigidity of the overcap, giving the lightweight overcap an even more “normal” feel to the consumer and allowing for improved automated handling. Examples of such reinforcing structures include one or more concentric stepped portions  19  as shown in FIG.  11  and radially extending ribs  21  as shown in FIG.  12 . The stepped portions preferably have a truncated cone shape and rise from the center of the central portion  18 . Where more than one stepped portion is incorporated into the overcap design, one or more stepped portions may be set below the plane of the center panel so that the total height of the stepped portions does not extend above the normal unreinforced height of the overcap. 
     Thus there is provided a lightweight overcap that decreases the amount of required material by up to 30% compared to conventional overcaps, resulting in a substantial cost savings in raw materials. The overcap can be used with composite, metal or plastic containers. 
     Other embodiments of the invention are contemplated which do not depart from the scope of the invention claimed. While the preferred form of the invention has been shown and described herein, it is to be understood that the invention is not to be taken as limited to the specific form described herein, and that changes and modifications may be made without departing from the true concept of the invention. It is therefore contemplated that the foregoing teachings and the appended claims define the present invention and any and all changes and modifications.