US2960134A - Stackable plastic container - Google Patents

Description

Nov. 15, 1960 1 .L..F0RNAS 2,960,134

l STACKABLE PLASTIC CONTAINE Filed June l, 1959 4- vrt United States Patent O STACKABLE PLASTIC CONTAINER Levi L. Fornas, North Hollywood, Calif., assgnor to Hollywood Plastics, Inc., a corporation of California Filed June 1, 1959, Ser. No. 817,313

1 Claim. (Cl. 150.S)

The present invention relates to a rectangular box integrally formed from resilient plastic material, and which is so formed as to provide rigid support for a loaded similar box when stacked upon it.

In fabricating stackable containers from plastic material it is inherently diflicult to produce a type of container which can be stacked to great heights, since the plastic material is flexible and does not usually provide rigid support. Itis desirable to economize on the amount of plastic material used, and it is also desired that the stacking lugs or stacking members provided in the box to receive and support the box next above it should occupy as little of the load space as possible.

In manufacturing plastic boxes or containers it is not only desirable that the container be integrally formed from a single sheet of plastic material, but it is also desirable that the plastic material have a substantially uniform thickness throughout the completed container. If the container is designed in such a way that some portions of the plastic material have a substantially greater or substantially smaller thickness than other portions, additional manufacturing cost is involved.

One object of the invention, therefore, is to provide a stackable container made of resilient plastic material, and in which rigid support of a superimposed similar .container is nevertheless achieved.

Another object of the invention is to provide `a stackable container which is integrally formed from a single sheet of resilient plastic material and which has a substantially uniform wall thickness throughout.

Yet a further object of the invention is to provide a stackable plastic container which is adapted to receive the vertical load stress of a superimposed stack of similar containers only at its corners, with the side and end walls thereof being placed in tension rather 4than in compression.

The above and other objects of the invention will be more readily apparent from the following description considered in conjunction with the accompanying drawing, in which:

Figure l is a perspective View of two of the novel containers provided by the present invention, one being stacked upon the other;

Figure 2 is a vertical cross sectional view of a corner of `the containers taken on the line 2 2 of Figure l;

Figure 3 is an elevational view of a corner of one of the containers viewed symmetrically with respect to the corner;

Figure 4 is a plan view of the corner taken on the line 4-4 of Figure 3;

Figure 5 is a bottom view of the corner taken on the line 5-5 of Figure 3; and

Figure 6 is an elevational View of the container corner taken at an angle of 90 degrees with respect to one of the associated outer walls, on the line 6 6 of Figure 4.

According to the invention the stackable box is integrally formed of resilient plastic material. 'Ihe side port the respective bottom corners of the superimposed.; The upper surfaces of the stacking lugs 11e at a` box. common elevation above the bottom of the box.

Precise vertical alignment of the stack is assured by the fact that each superimposed box is partially inserted into the box beneath it. Rigidity of support by the bottom box is achieved by virtue of the geometry of the; box and its stacking lugs, despite the resilience of the plastic material itself.

Since the walls slope outwardly, a vertical load stress near the top of each inner corner causes the main portion of each wall to be in horizontal tension. At each corner of the box the adjoining wall ends form an L- shaped beam which can carry the compressive load without buckling. Furthermore, the preferred form of the corner and stacking lug provide increased resistance to buckling while at the same time achieving minimum manufacturing cost by utilizing plastic material of substantially uniform thickness throughout.

I Referring now to the drawing, in Figure l a box 10 is stacked upon an identical box 20. Each of the boxes have side walls A, C and end walls B, D. The side and end walls slope slightly outwardly, hence the bottom of box 10 is partially inserted within the upper portion of box 20.

The various corners of the box are identical but are separately designated as corner 11 where end wall A and side wall B join, corner 12 where side wall B and end wall C join, corner 13 where end wall C and side wall D join, and corner 14 where side wall D and end wall A join. The flat bottom of each box is identified as F. Surrounding its periphery each box has an outwardly ared lip L which is conveniently adapted for manually holding or carrying the box.

According to the invention a portion of each corner of the box projects inwardly thereof so as to limit the downward extent by which a superimposed box may be inserted therein. The inward projection at each corner of the box therefore provides a stacking lug. In the preferred form of the invention illustrated herein the stacking lug is designed to achieve both maximum eiiiciency and maximum economy.

More specifically, the joining side and end walls are smoothly rounded at their upper and lower edges with the junctures being in alignment with each other. The intervening juncture portion designated as 16 slopes inwardly of the box with increasing height above the bottom of the box, and then at a predetermined distance above the bottom of the box the juncture extends horizontally outwardly at 17 to join the normally formed, smoothly rounded corner portion 18 which extends above it.

In Figure 4 the outward slope of wall B is indicated by line 21 which represents the smooth inner surface at the top of the wall before rounding olf, line 23 which represents the smooth inner surface at the bottom of the wall before rounding olf, and dotted line 22 which represents the outer surface of the bottom of the wall.

While in the preferred form of the invention the various portions of the plastic material are of uniform thickness, it will be understood that different thickness values may be used throughout the box if desired.

For convenience the box has been described herein as being rectangular, but it will be understood that the box may be made square if desired.

Other forms and modifications of the invention will be Patented Nov. l5, 1960..

apparent to those skilled in the art, and the invention is not to be limited to the specific features shown and described herein.

A stackable rectangular box integrally formed of resilier1-t plastic material of substantially uniform thickness throughout and having side and end walls which, from bottom to top, slope slightly outwardly to permit the bottom of a superimposed identical box to be partially'inserted therein, each corner thereof being formed in suoh a way that the junctures of the associated side and end walls at the upper and lower edges thereof are smoothly rounded and in alignment with each other, the intervening juncture portion sloping inwardly of the box with increasing height above the bottom of the box, and then at a predetermined elevation above the bottom of the box extending horizontally outwardly to join the upper por l tions of the side and end walls so as to provide near the top of the box a stacking support for the corresponding corner bottom surface of the superimposed box, whereby the Vertical load of the superimposed box produces a horizontal tension in said side and end walls.

References Cited in the tile of this patent UNITED STATES PATENTS 1,816,930 Finn Aug. 4, 1931 2,088,181 Swift July 27, 1937'H 2,857,947 Powers Oct. 28, 1958 2,889,072 Lapham June 2, 1959 FOREIGN PATENTS 609,142 Great Britain Sept. 27, 1948 544,833 Italy lune 20, 1956 742,516 1955 Great Britain Dec. 30,

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