Wraparound plastic corrugated case

Abstract

A plastic corrugated case is provided. The case is made of at least one extruded sheet having, in an unfolded state, an extrusion direction and a transverse direction perpendicular to the extrusion direction. The sheet has a cross-sectional profile parallel to the transverse direction, the cross-sectional profile having a first section, and a second section different from the first section.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to plastic cases, and more particularly to plastic corrugated cases.

2. Related Art

Cases or boxes are often used to ship and display multiple smaller containers of a products. For example, motor oil is usually sold in one quart plastic containers that are shipped in cases that hold either 6 or 12 of the one quart plastic containers. These cases are usually constructed of corrugated cardboard. If the cardboard cases become wet through contact with rain or other liquid, they become very weak and often fail. Also, to be opened, the cardboard cases often must be cut with a knife. This can lead to accidental cutting of the product containers within the case.

BRIEF SUMMARY OF THE INVENTION

In summary, embodiments of the invention provide a corrugated plastic case that has differing cross sections so that sections of the case that require more strength are stronger while sections requiring less strength use less plastic material.

Particular embodiments of the invention provide a plastic corrugated case, having at least one extruded sheet having, in an unfolded state, an extrusion direction and a transverse direction perpendicular to the extrusion direction, the sheet having a cross-sectional profile parallel to the transverse direction, the cross-sectional profile having a first section, and a second section different from the first section.

Other embodiments of the invention provide a one piece plastic corrugated case having, in an unfolded state, an extrusion direction. The case has a bottom panel having a cross-sectional profile perpendicular to the extrusion direction; a front panel attached to the bottom panel and having a cross-sectional profile perpendicular to the extrusion direction; a back panel attached to the bottom panel and having a cross-sectional profile perpendicular to the extrusion direction; a right side panel attached to at least one of the front panel, the back panel or the bottom panel and having a cross-sectional profile perpendicular to the extrusion direction; a left side panel attached to at least one of the front panel, the back panel or the bottom panel and having a cross-sectional profile perpendicular to the extrusion direction; and a top panel attached to at least one of the front panel, the back panel, the right side panel or the left side panel and having a cross-sectional profile perpendicular to the extrusion direction. The case is, in the unfolded state, a single piece of plastic, and at least one of the cross-sectional profiles changes along a direction perpendicular to the extrusion direction.

Other embodiments of the invention provide a method of producing a plastic corrugated case. The method includes extruding a first sheet having, in an unfolded state, an extrusion direction and a transverse direction perpendicular to the extrusion direction. The extrusion causes the first sheet to have a cross-sectional profile parallel to the transverse direction, the cross-sectional profile having a first section, and a second section different from the first section. The method further includes folding the first sheet to form at least a part of the case; and attaching portions of the first sheet to other portions of the first sheet or to portions of a second sheet to maintain the case in a folded state.

Further objectives and advantages, as well as the structure and function of preferred embodiments will become apparent from a consideration of the description, drawings, and examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention will be apparent from the following, more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings wherein like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements.

FIG. 1 is a perspective view of an example of a first embodiment of a case according to the invention;

FIG. 2 is a plan view of the case of FIG. 1 in an unfolded state;

FIG. 3 is a perspective view of a corner detail of the case shown in FIGS. 1 and 2;

FIG. 4 is a plan view of the corner detail shown in FIG. 3;

FIG. 5 is a plan view of a second embodiment of the invention; and

FIG. 6 is plan view of a third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention are discussed in detail below. In describing embodiments, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected. While specific exemplary embodiments are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations can be used without parting from the spirit and scope of the invention. All references cited herein are incorporated by reference as if each had been individually incorporated.

The above described problems with cardboard boxes can be eliminated by using plastic corrugated cases in accordance with the invention. Such plastic corrugated cases can be made from extruded sheets of corrugated plastics. However, with sheets of corrugated plastic having a uniform cross section, in order to make particular sections of the plastic corrugated sheet strong enough, other sections of the plastic corrugated sheet will be stronger then necessary. This results in using more plastic material than necessary and, therefore, a higher cost than necessary. Particular embodiments of the invention solve this problem associated with plastic corrugated sheets having a uniform cross section by altering the cross section of the plastic corrugated sheet so that particular sections of the plastic corrugated sheet are provided with only as much material as those sections require in the finished case.

FIG. 1 shows a case 1 in accordance with an exemplary embodiment of the invention. FIG. 2 shows a sheet of corrugated plastic that can be folded to form case 1. As shown in FIG. 1, case 1 has a bottom 10, a top 20, a front 30, a back 40, a left side 50 and a right side 60.

The sheet shown in FIG. 2 has a bottom panel 100 that forms bottom 10 of case 1. Top 20, front 30 and back 40 are formed by top panel 200, front panel 300 and back panel 400, respectability. Attached to front panel 300 are right side panel 310 and left side panel 320. Similarly, attached to back panel 400 are right side panel 410 and left side panel 420. To assemble case 1, right side panel 310 is folded along fold line 301 so that right side panel 310 forms a 90° angle with front panel 300. Similarly, left side panel 320 is folded along fold line 302 such that left side panel 320 forms a 90° angle with front panel 300. Front panel 300 is then folded along fold line 303 to form a 90° angle with bottom panel 100. At this point, a lower edge of left side panel 320 rests near fold line 102 of bottom panel 100 and a lower edge right side panel 310 rests near fold line 101 of bottom panel 100. Next, right side panel 410 is folded along fold line 401 to form a 90° angle with back panel 400 and left side panel 420 is folded along fold line 402 to form a 90° angle with back panel 400. Back panel 400 is then folded along fold line 403 to form a 90° angle with bottom panel 100. At this point, the lower edge of left side 420 rests on, or is proximate to, fold line 102 and a lower edge of right side panel 410 rests on, or is proximate to, fold line 101. A right flap 110 is then folded along fold line 101 and secured to right side panels 310, 410. Similarly, a left flap 120 is folded along fold line 102 and secured to left side panels 320, 420. Right flap 110 and left flap 120 can be secured by, for example, plastic welding or an adhesive. In this assembled position, an edge 311 of right side panel 310 preferably contacts, and is adhere to, an edge 411 of right side panel 410. Similarly, an edge 321 of left side panel 320 preferably contacts, and is adhered to, an edge 421 of left side panel 420. At this point, case 1 is ready to be filled with product.

After case 1 is filled with the product to be sold in case 1, top panel 200 is folded along fold line 203 to form a 90° angle with back panel 400 and closes case 1. Top panel 200 is secured in place by folding a front flap 210 along a fold line 204 and bonding front flap 210 to front panel 300 as shown in FIG. 1. A right side flap 220 is folded along a fold line 201 to form a 90° angle with top panel 200 and is bonded to right side panels 310, 410. Similarly, a left flap 230 if folded along a fold line 202 to form a 90° angle with top panel 200 and is bonded to left side panels 320, 420.

Right flap 220 and left flap 230 are provided with a right handle 225, and a left handle 235, respectively. Handles 225, 235 can be folded away from right side 60 and left side 50, respectively, to facilitate lifting of case 1. In this example, handles 225 and 235 are provided with grooves 227 and 237, respectively, to add strength to the handles.

In accordance with the invention, particular areas of case 100 are strengthened to sustain the loads placed on case 1 during use, while other portions of case 1 do not require strengthening. In FIGS. 2 and 3, strengthened areas are shown by cross hatching. One example of strengthening in accordance with the invention is shown in FIGS. 3 and 4. In this example, the corrugated plastic cross section in strengthened areas 440 and 445 have thicker top and bottom panels and thicker webs between the panels. This thickening is provided by using, for example, different die sizes during the extrusion process. In addition to the thickening discussed above, left side panel 420 and left side panel 320 are further strengthened by grooves 425 and 325, respectably. As shown in FIG. 2, similar grooves 315 and 415 are provided in right side panel 310 and right side panel 410, respectably. FIG. 3 also shows a strengthened area 240 in top panel 200. Strengthened area 240 provides top panel 200 with added resistance to breaking or deforming at the point at which top panel 200 contacts the top edges of left side panels 320, 420. Although FIG. 3 only shows one end of case 1, it is understood that the other end of case 1 can be similarly constructed.

As can be seen from FIG. 2, the various strengthened areas in this example can be produced in a sheet of corrugated plastic whose cross section is not uniform in a transverse direction B but is uniform along an extrusion direction A. Because of this, the sheet of corrugated plastic shown in FIG. 2 can be cut from a sheet of corrugated plastic produced by extrusion.

FIG. 5 shows an alternate embodiment of the invention in which strengthened areas 440′ and 445′ are corrugated, and non-strengthened areas are thin solid plastic sheets. Depending on the intended use of the case, the embodiment shown in FIG. 5 may provide sufficient strength while using less plastic.

FIG. 6 shows an embodiment of the invention including a corner reinforcement 500 that can be formed during the extrusion process as a part of, in this example, left side panel 420 and can be bonded to back panel 400 during assembly of case 1. Corner reinforcement 500 can provide added strength to the corners of case 1 and, thereby, allow reduction of the amount of plastic used in other sections of case 1 while maintaining the required strength. Similarly, a rib can be formed during extrusion on one or more of the panels in, for example, a central region of the panel to provide structural support for the case.

In the examples shown in the Figures, the left and right ends of case 1 are designed to be the primary load carrying members in the case. However, depending on the intended use of the case, different sections can be made stronger as appropriate. Also, the case and bottles to be carried in the case can be designed together so that sufficient strength is provided by the combination of the case and the bottles.

The various fold lines of the invention are preferably formed during the extrusion process so that no further scoring is necessary before assembly.

The embodiments illustrated and discussed in this specification are intended only to teach those skilled in the art the best way known to the inventors to make and use the invention. Nothing in this specification should be considered as limiting the scope of the present invention. All examples presented are representative and non-limiting. The above-described embodiments of the invention may be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described.

Claims

1. A plastic corrugated case, comprising: at least one extruded sheet having, in an unfolded state, an extrusion direction and a transverse direction perpendicular to the extrusion direction, the sheet having a cross-sectional profile parallel to the transverse direction, the cross-sectional profile having a first section, and a second section different from the first section.

2. The case of claim 1, wherein the sheet further comprises: a first panel; and a second panel attached to the first panel, wherein a cross-section of at least one of the panels is partially the first section and partially the second section.

3. The case of claim 2, wherein the second panel attaches to the first panel along a fold line.

4. The case of claim 3, wherein the fold line is parallel to the extrusion direction and is part of the cross-sectional profile.

5. The case of claim 3, wherein the fold line is parallel to the transverse direction.

6. The case of claim 3, wherein the first section is a corrugated cross-section.

7. The case of claim 6, wherein the second section is a corrugated cross-section that is stronger than the first section.

8. The case of claim 6, wherein the second section is solid.

9. The case of claim 2, wherein the cross-sectional profile has a protrusion that, when the sheet is in a folded state, forms a corner brace between the first panel and the second panel.

10. The case of claim 2, wherein the cross-sectional profile has a protrusion that, when the sheet is in a folded state, forms a structural rib on one of the first panel or the second panel.

11. The case of claim 3, wherein the entire case is formed from one piece of the extruded sheet.

12. A one piece plastic corrugated case having, in an unfolded state, an extrusion direction, the case comprising: a bottom panel having a cross-sectional profile perpendicular to the extrusion direction; a front panel attached to the bottom panel and having a cross-sectional profile perpendicular to the extrusion direction; a back panel attached to the bottom panel and having a cross-sectional profile perpendicular to the extrusion direction; a right side panel attached to at least one of the front panel, the back panel or the bottom panel and having a cross-sectional profile perpendicular to the extrusion direction; a left side panel attached to at least one of the front panel, the back panel or the bottom panel and having a cross-sectional profile perpendicular to the extrusion direction; and a top panel attached to at least one of the front panel, the back panel, the right side panel or the left side panel and having a cross-sectional profile perpendicular to the extrusion direction, wherein the case is, in the unfolded state, a single piece of plastic, and at least one of the cross-sectional profiles changes along a direction perpendicular to the extrusion direction.

13. The case of claim 12, wherein, in the unfolded state, the right side panel comprises a front right side panel attached to the front panel, and a back right side panel attached to the back panel; and the left side panel comprises a front left side panel attached to the front panel, and a back left side panel attached to the back panel.

14. A method of producing a plastic corrugated case, the method comprising: extruding a first sheet having, in an unfolded state, an extrusion direction and a transverse direction perpendicular to the extrusion direction, the extrusion causing the first sheet to have a cross-sectional profile parallel to the transverse direction, the cross-sectional profile having a first section, and a second section different from the first section; folding the first sheet to form at least a part of the case; and attaching portions of the first sheet to other portions of the first sheet or to portions of a second sheet to maintain the case in a folded state.

15. The method of claim 14, wherein the first sheet is extruded to further comprise: a first panel; and a second panel attached to the first panel, wherein a cross-section of at least one of the panels is partially the first section and partially the second section.

16. The method of claim 15, wherein the first sheet is extruded such that the second panel attaches to the first panel along a fold line.

17. The method of claim 16, wherein the fold line is parallel to the extrusion direction and is part of the cross-sectional profile.

18. The method of claim 16, wherein the first section is extruded as a corrugated cross-section.

19. The method of claim 18, wherein the second section is extruded as a corrugated cross-section that is stronger than the first section.

20. The method of claim 18, wherein the second section is a solid extrusion.