CROSS REFERENCES TO RELATED APPLICATIONS

Not applicable.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

The present invention relates to devices for releasably closing cartons and boxes.

The conventional corrugated cardboard carton or box typically has four top flaps, one extending from each of four side walls. The outer top flaps overlie the inner top flaps, forming a double thickness of corrugated material. An effective closure or seal can be ensured by applying strapping tape, staples, or the like. The carton may also be closed by interleaving the top flaps one with other, although this method of closure will tend to distort the box flaps and is not always satisfactory. In my U.S. Pats. Nos. 3,545,801 and 7,284,688, the disclosures of which are incorporated by reference herein, I disclosed molded box closure devices having generally disc-shaped configurations providing a convenient reusable closure for cartons readily fabricated in an injection molding process.

What is needed is a resuable box closure device which is of constant cross section such that it may be fabricated through a plastic or other extrusion process, yet which is easily and securely mounted to close a box.

SUMMARY OF THE INVENTION

The box closure device of this invention facilitates the fast and certain installation and easily releasable engagement of the flaps of a box in a closed configuration. The device has a lower element which extends generally in a first plane. An upper element is connected to the lower element by a web, such that portions of the box flaps' upper and lower surfaces are engaged between the upper element and the lower element. The upper element may extend outwardly from both sides of the web less than the lower element, and may be concave opening downwardly towards the lower element.

It is an object of the present invention to provide a box closure device which is easily manipulated and speedily installed to close the flaps of a box and which does not interfere with the stacking of one closed box upon another.

It is another object of the present invention to provide a box closure device which has a constant cross-section to permit its ready fabrication from plastic or similar material in an extrusion process.

Further objects, features and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top isometric view of a box closure device of the present invention.

FIG. 2 is an enlarged end view of the device of FIG. 1.

FIG. 3 is a perspective view of the device of FIG. 1 being installed to close the top flaps of a box.

FIG. 4 is a cross-sectional view of the device of FIG. 2 installed within a box, shown in fragmentary cross-sectional view.

FIG. 5 is a top plan view of the device of FIG. 1.

FIG. 6 is an end view of an alternative embodiment of the box closure device of the present invention, the device having internal gripping ribs.

FIG. 7 is an end view of another alternative embodiment of the box closure device of the present invention, the device having internal flexible gripping fingers extending at 45 degrees.

FIG. 8 is an end view of yet another alternative embodiment of the box closure device of the present invention, the device having internal flexible gripping fingers extending at 60 degrees.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring more particularly to FIGS. 1-8, wherein like numbers refer to similar parts, a box closure device 20 is shown in FIGS. 1-4. As shown in FIG. 3, the closure device 20 is used with a conventional box 22. The box may be a corrugated cardboard container, or may be fabricated of other material such as paperboard or plastic. The box 22 has side walls 24 from which extend a first flap 26 and a second flap 28. The box may have a third flap 30 and a fourth flap 32 which extend beneath the first and second flap when the box 22 is closed.

As shown in FIG. 1, the closure device 20 is a unitary plastic element, preferably formed in an extrusion process, of, for example, high density polyethylene or rigid polyvinyl chloride (RPVC). Other appropriate moldable material may also be employed. The device 20 has a lower element 34 with portions which extend generally in a first plane. An upper element 36 is connected to the lower element and spaced above it by an intermediate web 38. The web spaces the upper element 36 from the lower element to receive portions of the first flap between the upper element and the lower element on one side of the web 38, and portions of the second flap between the upper element and the lower element on an opposite side of the web.

The upper element 36 is constructed to resiliently engage the flaps inserted between it and the lower element, and to accommodate some variation in the thickness of the flaps to be grasped therebetween. The upper element 36 has a first part 40 which extends outwardly in a first direction from the web 38 along a first line of attachment 42 which is spaced a first distance from the lower element, and a second part 44 which extends from the web in a second direction from the web along a second line of attachment 46 which is spaced from the lower element a second distance, and wherein the second direction is opposite the first direction. As shown in FIG. The first part 40 is continuous with the second part 44, so that the upper element defines an uninterrupted surface.

The first part 40 has an outer edge 48 and the second part 44 has an outer edge 50, each of which outer edges 48 are spaced from the lower element a distance which is less than the spacing of the parts 40, 44 respectively where they extend from the web. The first part and the second part are resilient to be biased against the box first flap and second flap received between the upper element and the lower element. As shown in FIG. 5, the distance between the upper element first part outer edge and the upper element second part outer edge measured perpendicular to the web is less than the width of the lower element measured perpendicular to the web. In other words, the upper element is not as wide as the lower element.

The installation of the box closure device 20 in a conventional box 22 is illustrated in FIG. 3. The first flap 26 and the second flap 28 are brought to a closed configuration so that the flaps overlie the lower element 34 where it protrudes beneath the upper element 36. As shown in FIG. 1, the perimeter of the upper element, which includes the outer edges of the first part and the second part of the upper element, may have rounded corners, preferably with a radius of one quarter inch or greater, further assisting in exposing the lower element so that the flaps may readily gain entry between the upper and lower elements of the box closure device. The resiliently disposed upper element is urged upwardly to receive the box flaps, and once the portions of the flaps are inserted into the closure device they are resiliently gripped between the upper and lower elements. However, once inserted the box closure device may be moved inwardly to the center of the box top. Or, in a larger box, two or more closure devices 20 may be used.

The closure device 20 holds the box flaps from springing upward, yet may readily be removed without significantly damaging the box. Hence the box may be used multiple times. Even when the box is too worn to be used again, the closure device 20 may still be usable. As shown in FIG. 2, the upper element 36 may be a continuous curve, such that the upper element first part 40 and second part 44 are concave, opening towards the lower element 34.

The closure device 20 may be made in various sizes to suit a range of box applications. The illustrated embodiment may be about 12 inches long, and about 3 inches wide, with a spacing of about 0.185 inches between the upper element and the lower element at the web, decreasing to about 0.107 inches at the outer edges 48, 50 of the upper element parts. The intermediate web 38 may be about 0.08 inches thick. The outer edges of the upper element and the lower element are preferably rounded, for example with a radius of about 0.09 inches.

An alternative embodiment box closure device 60 is shown in FIG. 6, which has a lower element 62 connected to an upper element 64 by an intermediate web 66. The lower element has a first part 68 extending to one side of the web 66, and a second part 70 which extends to the other side of the web. A plurality of axially extending triangular ridges 72 extend upwardly from the lower element on both the first part 68 and the second part 70. Each ridge 72 extends continuously in an axial direction along the lower element 62, and has one face which is approximately perpendicular to the lower element 62, and an adjoining face which extends at an angle of about 45 degrees from the lower element. The ridges 72 may extend towards the upper element about 0.075 inches, leaving a gap of about 0.14 inches between the uppermost tips of the ridges and the upper element. The ridges may be evenly spaced along the lower element, although the region closest to the web 66 may be clear of ridges, as the deflection of the lower element will be less in that region.

Another alternative embodiment box closure device 74 is shown in FIG. 7, which has an upper element 76 connected to a lower element 78 by an intermediate web 80. The lower element has a first part 82 extending to one side of the web 80, and a second part 84 which extends to the other side of the web. The device 74 is similar to the closure device 60, with the difference that the fins are longer to form parallel sided flexible fingers 86. A plurality of the axially extending flexible fingers 86 extend upwardly from the lower element 78 on both the first part 82 and the second part 84 of the lower element. Each finger 86 extends continuously in an axial direction along the lower element 82. The fingers 86 may extend towards the upper element about 0.075 inches, leaving a gap of about 0.14 inches between the uppermost tips of the fingers and the upper element. The flexible fingers 86 serve to impart resilient gripping of the closure device to the box flaps. The fingers 86 are preferably provided on the lower element to engage the underside of a box flap, such that any depressions which may be formed by the engagement of the fingers 86 will not generally be visible from the exterior of the box.

Another alternative embodiment box closure device 88 is shown in FIG. 8, which is similar to the device 74, with an upper element 94 spaced by a web 89 above a lower element 92, except that the fingers 90 extend from the lower element 92 at about 60 degrees. The spacing between the tops of the fingers 90 and the upper element 94 may be similar.

It should be noted that although box closure devices having fingers extending at about 45 and about 60 degrees have been disclosed, devices with fingers extending at different angles may also be fabricated, so long as the fingers still serve to engage the box flaps within the device.

It is understood that the invention is not limited to the particular construction and arrangement of parts herein illustrated and described, but embraces all such modified forms thereof as come within the scope of the following claims.