CA2334452A1 - Packaging device - Google Patents

Abstract

A container comprising a base including a floor, an upstanding continuous sidewall extending from the floor and defining a first perimeter, a cavity disposed within the first perimeter, and a horizontal flange extending peripherally and laterally from the sidewall, wherein the horizontal flange includes first and second spaced apart slots to define a hinge therebetween, and a lid connected to the hinge. The sidewall can terminate at a top edge, such that the horizontal flange extends from the top edge. The horizontal flange can include a flange peripheral edge, such that the first and second slots extend inwardly from the flange peripheral edge. The horizontal flange can extend about the first perimeter. The lid can include a lid peripheral edge and a skirt depending downwardly from the lid peripheral edge, such that the skirt is connected to the hinge. The skirt can snap over the horizontal flange when the container is in the closed position.

Description

PACKAGING DEVICE
Field of Invention The present invention relates to plastic food containers and, in particular, to a mechanism for enabling improved sealing of plastic food containers.
Background of the Invention Plastic packaging for containing and exhibiting a wide variety of articles are well-known and various arrangements are known to secure the packages closed. Such packaging is typically formed using cut-in-place thermoforming technology. In using cut-in-place thermoforming technology, a mould is provided having structural features corresponding to those of the desired container.
Typically, such thermoformed containers include upstanding sealing elements or beads for locking a base portion against a lid portion and, thereby, substantially sealing the container. An example of a plastic food container formed u~;ing cut-in-place thermoforming technology is disclosed in U.S.
Patent No. 5,169,014 issued to F(examer. Unfortunately, as with other plastic food containers formed using cut-in-place thermoforming technology, the plastic food container disclosed in U.S.
Patent No. 5,169,014 suffers from the absence of means for effecting adequate friction locking or sealing of the container in the region of the hinge joining the lid portion to the base portion of the formed container. As such, desired sealing of the container about this region cannot be realized, thereby affecting the shelf life of any food products stored in such containers.
Summary of the Invention It is a principal object of the present invention to provide an improved plastic container.
In its broad aspect, the container of the invention comprises a base including a floor, an upstanding continuous sidewall extending from the floor and defining a first perimeter, a cavity disposed within the first perimeter, and a horizontal flange extending peripherally and laterally from the sidewall, wherein the horizontal flange includes first and second spaced apart slots to define a hinge therebetween, and a lid connected to the hinge. The sidewall can terminate at a top edge, such that the horizontal flange extends from the top edge. The horizontal flange can include a flange peripheral edge, such that the first and second slots extend inwardly from the flange peripheral edge.

The horizontal flange can extend about the first perimeter. The lid can include a lid peripheral edge and a skirt depending downwardly from the lid peripheral edge, such that the skirt is connected to the hinge. The skirt can snap over the horizontal flange when the container is in the closed position.
By joining the lid of the container to a corresponding base with a slotted hinge formed in a peripheral flange extending about: the periphery of the base, the lid can be slipped rearwardly to facilitate friction locking of the lid to the base by a sealing member in a region proximate to the hinge, thereby enhancing sealing of the container.
Brief Description of the Drawings Further objects and advantages will appear from the following detailed description of the invention, taken together with the following drawings in which:
Figure 1 is a front perspective view of an embodiment of a container of the present invention, showing the lid portion closed against the base portion of the container;
Figure 2 is a sectional side elevation. view, partly cut-away, of the container of Figure 1, taken along the line 2-2 in Figure 1, when the container is in the closed position;
Figure 3 is a top perspective view of the container of Figure 1, showing the container in an open position;
Figure 4 is a sectional side elevation view, partly cut-away, of the container of Figure 1, taken along the line 4-4 in Figure :3, when the container is in the open position illustrated in Figure 3;
Figure 5 is a bottom plan elevation view taken along the lines 5-5 in Figure 2;

Figure 6 is a bottom plan view, partly cut-away, taken along the lines 6-6 in Figure 4;
Figure 7 is a perspective view of a. second embodiment of a container of the present invention, showing the container in an open position;
Figures 8 - 12 are schematic cross-sectional views of a moulding apparatus for thermoforming the container of Figure 1 from a thermoplastic sheet, illustrating the various positions of the moulding apparatus during formation of the container;
Figure 13 is a top perspective view of a mould element of the moulding apparatus illustrated in Figures 8 - 12;
Figure 14 is an illustration of Detail "A" of Figure 13; and Figure 15 is a sectional side elevation view of the mould element taken along the lines 15-15 in Figure 14.
Detailed Description of the Invention Figures 1 and 2 show an embodiment of a container 10 of the present invention.
Container includes a lid 12 hinged to a base 14. A packaging cavity is provided when lid 12 covers base 14.
Refernng to Figures 1, 2, and 3, lid 12 is formed with a top 2 and sidewalk 3 and includes cavity 5. The sidewalk 3 are characterized by a top edge 4, defining a perimeter of lid. Lid 12 has a continuous horizontal flange 16 extending peripherally about the entire perimeter 26 of lid 12 from top edge 4 to a peripheral edge 11. A downwardly depending skirt 24 extends from peripheral edge 11 and is provided about the entire perimeter 26 of horizontal flange 16 and is characterized by a peripheral edge 25.

Base 14 is formed with a floor 6, upstanding sidewalk 8 extending from floor 6 and includes cavity 17. The sidewalls 8 are characterized by a top edge 9, defining a perimeter 15. A
corresponding continuous horizontal flange 18 extends peripherally about the entire perimeter 15 of base 14 from top edge 9, and provides a surface for seating horizontal flange 16 when container is in a closed position. Horizontal flange 18 includes an inner peripheral edge 20 and an outer peripheral edge 22. Inner peripheral edge 20 helps define perimeter 15.
Horizontal flange 18 provides a hinge 28 for joining lid 12 to base 14. In this respect, hinge 28 extends from and is integral with skirt 24. Referring to Figures 5 and 6, horizontal flange 18 is slotted along its outer peripheral edge 22 at a first outer peripheral edge location 30 to form a slot 31 having a first inwardly extending outer peripheral edge 32 and an opposing second inwardly extending outer peripheral edge 3fr. Edge 32 extends inwardly, in a general direction towards inner peripheral edge 20, from a first en.d 36 at first outer peripheral edge location 30 to a second end 38 disposed closer to inner peripheralL edge 20. A first end 40 of edge 34 joins with edge 32 at second end 38. Edge 34 extends outwardly from first end 40, in a general direction towards the outer peripheral edge 22. Edge 34 is joined at a second end 42 to skirt 24. In the embodiment illustrated, edge 34 is joined to skirt 24 at a first peripheral edge 25a of skirt 24.
Horizontal flange 18 is further similarly slotted at a second outer peripheral edge location 44 along its outer peripheral edge 22. In this respect, the slot 45 formed at second outer peripheral edge location 44 comprises a first inwardly extending outer peripheral edge 46 and an opposing second inwardly extending outer peripheral edge 48. Edge 46 extends inwardly, in a general direction towards inner peripheral edge 20, from a first end 50 at second outer peripheral edge location 44 to a second end 52 disposed closer to inner peripheral edge 20. A first end 54 of edge 48 joins with edge 46 at second end 52. Edge 48 extends outwardly from first end 54, in a general direction towards the outer peripheral edge 22. Edge 48 is joined at a second end 56 to skirt 24. In the embodiment illustrated, edge 48 is joined to skirt 24 at a second peripheral edge 25b of skirt 24.

Edges 34 and 48 define hinge 28, which is joined to skirt 24. As such, hinge 28 is formed from slots 31 and 44 provided in the outer peripheral edge 22 of horizontal flange 18. Hinge 28 is j oined to skirt 24 such that skirt 24 extends around outer peripheral edge 22 of horizontal flange 18, and preferably, snaps over horizontal flange 18 when container 10 is in a closed position (see Figure 1).
A locking arrangement is fizrther provided bybead 100 provided on flange 16 and depending therefrom, and a corresponding recess 102 formed on flange 18 (see Figures 2 and 4). Bead 100 mates with recess 102 to form a friction area that acts as a lock 104 when container 10 is in a closed position, thereby securely maintaining container 10 in closed position when lock 104 is formed.
Recess 102 is provided at inner peripheral edge 20 of horizontal flange 18. In particular, recess 102 including sidewall 106 having a surface 108, which extends downwardly from inner peripheral edge 20 to join with nesting flange 110. Nesting flange 110 presents a surface 112 substantially orthogonal to surface 108. Bead 100 includes a sidewall 114 extending upwardly (when container is open) from flange 16 of lid 12, such sidewall 114 presenting a surface 116.
Sidewall 114 joins to a nesting flange 118 presenting a surface 120 substantially orthogonal to surface 116. When container 10 is in a closed position, surface :L 16 fractionally engages surface 106 and surface 120 fractionally engages surface 112, to thereby form lock 104.
Alternative locking arrangements can be provided for securely locking lid 12 to base 14 to maintain container 10 in a closed position. F'or instance, and referring to Figure 7, flange 16 may include a male element 130 extending upwardly (when container 10 is open) therefrom.
Corresponding female elements 132 are formed on flange 18. Each ofrnale elements 130 is adapted to be received within corresponding female elements 132 in snap engagement to secure lid 12 to base 14.
Reference is now made to Figures 8 to 12 which show an apparatus 211 for thermoforming the container 10 of Figure 1 from a thermoplastic sheet 201 using cut-in-place thermoforming technology. Figures 8 to 12 show the apparatus 211 including a mould having an upper mould plate 202 and a lower mould plate 204 which are moveable vertically towards and away from each other between an open position (Figure 12) and a substantially closed position (Figure 10).
Upper mould plate 202 includes an upper base plate 206 (not shown on Figure 8), a mould element 208 defining a mould cavity 210, and a cutting die 212 provided peripherally about mould cavity 210. Mould element 208 includes apertures (not shown) which communicate with a source of compressed air for facilitating heating of the plastic sheet as will be described in more detail below. Lower mould plate 204 includes a cutting surface 214 and a heating plate 216. Cutting surface 214 includes apertures (nol; shown) which communicate with a source of compressed air for facilitating formation of the final :shape of container 10, as will be described in more detail below.
Mould plates 202 and 204 are opened and closed in a moulding cycle, resulting in the formation of package which is moulded and cut from a plastic sheet 201. As a first step, plastic sheet 201 is fed into a thermoforming area 218 provided between mould plates 202 and 204 (Figure 8).
A first toggle movement cause upvrard vertical movement of the lower mould plate 204 towards the upper mould plate 202 and to a po;~ition where the cutting die 212 is embedded in plastic sheet 201 but has not cut right through plastic sheet 201. Next, compressed air is injected from the mould element 208, enabling complete contact of plastic sheet 201 with the lower mould plate 204 to assist in uniform and rapid heating ofplastic sheet 201. As the thermoplastic material reaches the optimum forming temperature, the air is e~;hausted from the mould element 208 (Figure 9). Forming air pressure is then applied from the apertures in the lower mould plate 204.
Because plastic sheet 241 has been heated, plastic sheet 201 is sufficiently elastic so that the applied forming air pressure forces plastic sheet 201 against the mould. element 208 and into every detail of the mould cavity 210. Next, the forming air is vented and a second toggle movement causes further upward movement of the lower mould plate 204 towards upper mould plate 202 and to the substantially closed position where the cutting die 212 has cut through plastic sheet 201 (Figure 10). The lower mould plate 204 is then moved away from the upper mould plate 202, effecting opening of the mould element 208 (Figure 11 ). The formed container 10 is then ej ected with pressurized air and can then be transported to the stripping and stacking stations (Figure 12).

The mould element 208 Will now be described in more detail, with reference to Figures 13 to 15. To facilitate formation of container 10, mould element 208 includes a first mould cavity 220 and a second mould cavity 222. First mould cavity 220 facilitates formation of cavity 5 of lid 12 of container 10, while second mould cavity 222 facilitates formation of cavity 17 of base 14.
Cutting die 212 peripherally extends about mould cavities 220 and 222. Cutting die 212 includes perimeter die 224 which separates container 10 from plastic sheet 201 and forms the perimeter of container 10. Cutting die 212 further includes internal trim dies 226 and 228 which cut slots 31 and 45 from plastic sheet 201. Internal trim dies 226 and 228 are disposed within the perimeter of perimeter trim die 224. Extending between and j oining internal trim dies 226 and 228 is gated hinge die 230.
Gated hinge die 230 is adapted not to cut completely through plastic sheet 201 when upper mould plate 202 closes against lower mould plate 204 in the position illustrated in Figure 10, thereby maintain joinder of lid 12 with base 14 by means of hinge 28. In this respect, gated hinge die 230 is formed with a serrated upper edge 232 including alternating raised edges 234 and depressed edges 236. Serrated upper edge 232 is vertically lower at all points than trim dies 224, 226, and 228.
When upper mould plate 202 closes against lower mould plate 204 as in the position illustrated in Figure 10, raised edges 234 partly cut through or embed themselves within plastic sheet 241 interposed between the upper and lower mould plates 202 and 204. This is even though, simultaneously, trim dies 224, 226~, and 228 cut completely through this same plastic sheet 201. As such, gated hinge die 230 merely causes creasing of hinge 28, thereby facilitating bending of hinge 28 to open and close lid 12 relative to base 14.
Although the disclosure describes and illustrates preferred embodiments of the invention, it is to be understood that the invention is not limited to these particular embodiments. Many variations and modifications will now occur to those skilled in the art. For definition of the invention, reference is to be made to the appended claims.

Claims (10)

1. A container comprising:
a base including a floor, an upstanding continuous sidewall extending from the floor and defining a first perimeter, a cavity disposed within the first perimeter;
a horizontal flange extending peripherally and laterally from the sidewall, wherein the horizontal flange includes first and second spaced apart slots to define a hinge therebetween; and a lid connected to the hinge.

2. The container as claimed in claim 1 wherein the sidewall terminates at a top edge, and wherein the horizontal flange extends from the top edge.

3. The container as claimed in claim 1 wherein the horizontal flange includes a flange peripheral edge, and wherein the first and second slots extend inwardly from the flange peripheral edge.

4. The container as claimed in claim 1 wherein the horizontal flange extends about the first perimeter.

5. The container as claimed in claim 1 wherein the lid includes a lid peripheral edge and a skirt depending downwardly from the lid peripheral edge, and wherein the skirt is connected to the hinge.

6. The container as claimed in claim 1 wherein the lid includes a lid peripheral edge defining a second perimeter and a skirt depending downwardly from the lid peripheral edge and about the second perimeter, and wherein the skirt is connected to the hinge.

7. The container as claimed in claim 6 wherein the skirt snaps over the horizontal flange when the container is in the closed position.

8. The container as claimed in claim 2 wherein the horizontal flange includes a first peripheral edge, and wherein the first and second slots extend inwardly from the first peripheral edge.

9. The container as claimed in claim 8 herein the lid includes a second peripheral edge defining a second perimeter and a shirt depending downwardly from the second peripheral edge and about the second perimeter, and wherein the skirt is connected to the hinge.

10. The container as claimed in claim 9 wherein the skirt snaps over the horizontal flange when the container is in the closed position.