Container Fastening Means

Abstract

Deformable plastic containers, generally foamed, are widely used in the food service field where containers are filled at one location and transmitted to another location. These normally are either two-piece containers where a lid and base member snap together or one-piece having a hinged common border and a snap-in feature at the other end.

Description

Disclosed is an improvement in the locking means by which the top and bottom of the container are locked together.

FIELD OF THE INVENTION

This invention relates to containers having top and bottom portions adapted to be locked together.

PRIOR ART

The present invention represents an improvement over the structure shown in Cyr et al. U.S. Pat. No. 3,633,785 (1972), the general description thereof being incorporated herein by reference.

SUMMARY OF THE INVENTION

This invention relates to containers made of deformable plastic having first and second members. For heat insulating properties, such containers are frequently made of foamed plastic such as described by Cyr et al. but the invention is equally applicable solid plastic containers. One of the members constitutes the top of the container and the other the bottom thereof. Each member has a generally flat surface although one or both can be divided into compartments where a variety of foods are served in one container. One member has a generally outwardly extending sidewall attached to the flat surface and, at the end of said sidewall, a lip extending outwardly in a direction generally parallel to the flat surface of the member. The other member is adapted to lock in place on the lip of the first member. To this end, structure is provided so that there is a frictional engagement between the lip of the member described and the sidewall attached to the second member. The sidewall on the second member has four sloping members or sections, the first sloping outwardly from the flat surface, the second sloping outwardly from the end of the first at an angle of 10.degree. to 45.degree., preferably 20.degree. to 30.degree., from the flat surface. The third slopes inwardly from the end of the second and the fourth again slopes outwardly. The apex of angle between the second and third sections engages the lip 15 on the other member and the fourth surface, which slopes outwardly, serves to force the lip into position when the members are pushed together. Where two separate members are used, the structure described generally extends all of the way around the container although, on rectangular containers satisfactory results can frequently be obtained where the structure described is present only on two opposite sides. For circular containers, the particular structure is present completely around the circumference.

When hinged containers are used in which the top and bottom are formed in one piece with an integral hinge therebetween, the particular frictional engaging surfaces need only be present on the edges opposite the contiguous hinged portion.

Thus, one aspect of the invention comprises a container made from a continuous sheet of deformable foamed plastic comprising first and second portions hinged together along a contiguous section, said first and second portions each including circumferential lips which abut when the container is closed, the first member also having, integral with the lip thereof, receiving means which includes a locking portion opposite the contiguous section, said locking portion including a reverse-tapered sidewall which provides means into which the lip of the second member is force fitted upon closure of the container wherein the improvement consists of: the portion of said circumferential lip of the first member which is integral with the second member receiving means which includes the locking portion opposite the contiguous section being sloped at a 10.degree. to 45.degree. slope away from the lip such that said portion of the lip of the second member which comes into contact with the reverse-tapered sidewall locking portion is free to pass below the abutting circumferential lips during closure.

BRIEF DESCRIPTION OF THE DRAWING

Accompanying and forming a part of this application is a drawing in which:

FIG. 1 shows a plan view of one form of the container of the present invention.

FIG. 2 is a perspective view of the container of FIG. 1, in closed position, party in section.

FIGS. 3, 4, and 5 show the closure of the prior art, FIG. 3 showing a desired closed structure, while FIGS. 4 and 5 show difficulties which arise due to deformation of the plastic material.

FIGS. 6 and 7 illustrate the structure of the invention, FIG. 6 just before closing and FIG. 7 showing the top and bottom in closed position.

The terms "top" and "bottom" are used herein interchangeably and the top in one structure can serve as the bottom in another structure. Stated in another way, the figures can be viewed upside down and what functions as the top in one use may be the bottom in another.

An object of the present invention is to produce a container of deformable plastic material having an improved closure system.

SPECIFIC EMBODIMENTS OF THE INVENTION

Directing attention to the drawing, our invention will be described in more detail. For an understanding of the problem, attention is first directed to FIGS. 3, 4, and 5. The prior art lip configuration is shown in FIG. 3. This closure works quite adequately when both members were properly formed but if one or both are distorted, which is a common occurrence either through process deviations or from handling or shipping damage, the closure fails as shown in FIGS. 4 and 5. The closure of the present invention is designed to overcome this problem.

The one-piece structure is shown in FIGS. 1 and 2. The first member 9 having a generally flat area 11 is hingedly fixed to the second member 10 having generally flat area 12 by means of a hinge section 13. The first member 9 has sloping sidewalls 14 which extend outwardly and upwardly from the flat surface 11. Extending outwardly from the sloped wall sections 14 is a lip 16 which extends outwardly substantially parallel to flat surface 11. If desired, an indentation 17 can be provided to facilitate opening and closing of the container.

Second member 10 has the sloping sidewalls 18 which extend outwardly and upwardly from the flat surface 12. In the hinged version of our invention we provide a lip 16 at the outer end of sidewall 18 along the contiguous or hinged portion B and on the sides adjacent thereto. Lips 15 and 16 abut when the container is closed. Up to this point, the structure is conventional and that shown in the Cyr et al. patent, supra. The novel feature resides in the addition of a sloping section 19, sloping sidewall 18, at the end of member 12 opposite the hinged portion 13. This slopes outwardly at an angle of 10.degree. to 45.degree., preferably 20.degree. to 30.degree. from the plane of the flat surface 12. At the end of surface 19 is an inwardly sloping or reverse-tapered sidewall surface 21. The apex 20 of the angle between surface 19 and surface 21, the second and third sloping portions of the wall portion engage the outer end of lip 15 on the other member in the closed position. Finally, another outwardly extending portion 22 is provided which acts as a lever to force the frictionally engaging members outwardly as they are pressed into position. Optionally, a horizontal portion can be added to outwardly extending portion 22 if desired.

FIGS. 6 and 7 show the structure of our invention as the two members are brought together, FIG. 7 just before closing and FIG. 8 in the closed position. In FIG. 6 as the first member 9 descends downwardly, lip 15 contacts inclined plane 22. Since the material is deformable, the wall of member 9 is pushed inwardly while a wall of member 10 is pushed outwardly. This allows 15 to pass into the space between sections 19 and 21. Even if the wall members of either top or bottom are distorted, the edge 15 will still be securely locked within the angle made by sections 19 and 21. While not wishing to be bound by any theory of operation, we believe that the advantage of the invention is a result of the fact that, in closing, lip 15 can be pushed below apex 20. If there is deformation, as shown in FIGS. 4 or 5, upon relaxation lip 16 assumes the position shown in FIG. 7.

In addition to the hinged container just described, the invention is equally applicable to two-piece containers. Referring to FIG. 2, one of the pieces would have the sloping wall 14 and lip 15. The other piece would have the combinations of sloping sections 18, 19, 21, and 22. For a generally circular container the described structure generally extends completely around the circumference. In a generally rectangular container the described structure can extend around all four sides or simple abutting lips, as 15 and 16, can be formed on two opposite sides while the interlocking structure can be used on the other sides.

Modifications of the present invention will be apparent to those skilled in the art upon reading the present disclosure.

Claims

We claim:

1. A container made of deformable plastic having first and second members, one of said members constituting the top of the container and the other the bottom thereof, each member being provided with a generally flat surface, one of said members having a sidewall attached to said flat surface which slopes away from said planer surface and a lip extending outwardly from the end of said sidewall, said lip being generally parallel to the flat surface of said member; the other of said members having a sidewall attached to the flat surface thereof adapted to engage frictionally the lip on the other of said members and having four sloping sections, the first sloping outwardly from the flat surface, the second sloping outwardly from the end of the first at an angle of 10.degree. to 45.degree. from the flat surface, the third sloping inwardly from the end of the second, and the fourth sloping outwardly from the end of the third, the apex of the angle between said second and third sections engaging the lip on said other member, said fourth cooperating with said lip to force said lip into position when said members are pushed together; said sidewalls extending substantially completely around said first and second members when these are separate pieces, and when said first and second members are hinged together along a contiguous section, at least the sidewalls opposite said contiguous section having the structure set forth.

2. The container of claim 1 wherein the angle between said second sloping section and the flat surface is 20.degree. to 30.degree..

3. A container made from a continuous sheet of deformable foamed plastic comprising first and second portions hinged together along a contiguous section, said first and second portions each including circumferential lips which abut when the container is closed, the first member also having, integral with the lip thereof, receiving means which includes a locking portion opposite the contiguous section, said locking portion including a reverse-tapered sidewall which provides means into which the lip of the second member is force fitted upon closure of the container wherein the improvement consists of: the portion of said circumferential lip of the first member which is integral with the second member receiving means which includes the locking portion opposite the contiguous section being sloped at a 10.degree. to 45.degree. slope away from the lip such that said portion of the lip of the second member which comes into contact with the reverse-tapered sidewall locking portion is free to pass below the abutting circumferential lips during closure.

4. The container of claim 3 wherein the slope is from 20.degree. to 30.degree..