Box With Interlocking Inner Wall Panels

Abstract

A four sided box formed from a substantially rectangular blank having reinforced side walls formed of inner and outer side panels, which inner side panels are extensions of the outer side panels folded to lie flat against the inner faces of the walls, the adjacent edges of the inner side panels having matching projections and indentations which form mating locks when the panels are folded into place and the adjacent edges of the inner side panels are pressed against each other.

Description

BACKGROUND OF THE INVENTION

Boxes with reinforced side walls formed of inner and outer side panels, which inner side panels are extensions of the outer side panels reverse folded to lie flat against the inner faces of the wall panels, are well known. It is common practice to lock such inner panels in place with one or more tabs on the inner panel fitting into slots or cutouts in the side or bottom edges of the box (U.S. Pat. Nos. 2,965,279, 1,926,608, 2,702,663). This necessitates accurate cutting of the blank in remote areas of the blank to insure registry of the tab and slot when the box is set up.

The slots between the adjacent inner panels with the matching projections and indentations in the adjacent edges, as illustrated in the blank form and described and claimed herein, are more accurate, insure a positive matching lock, and are simple to make. Furthermore, even if the projections and indentations are not uniform throughout, they will still mate if they match each other.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a box with reinforced side walls formed of inner and outer side panels with the adjacent edges of the inner side panels having matching projections and indentations which mate to lock the inner panels in place against the wall panels.

It is a further object to provide a blank for the box of the present invention which is simple and economical to manufacture and can be easily set up into a box.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages will become apparent from the following description which is to be taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a plan view of the blank showing the score lines, cutouts and slots which define the various panels of the box of the present invention;

FIGS. 2, 3 and 4 are perspective views of the blank of FIG. 1 showing the folding of certain panels to complete one form of bottom;

FIG. 5 is a perspective view of the completed box with the inner side panels folded inwardly against the side walls;

FIG. 6 is an enlarged cross-sectional view along the line 6--6 of FIG. 5;

FIG. 7 is an enlarged cross-sectional view along the line 7--7 of FIG. 5; and

FIG. 8 shows a modified form of the projections and indentations for locking the inner panels in place.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings there is shown in FIG. 1 a flat substantially rectangular blank of sheet material, such as corrugated board, fiberboard or the like of a weight suitable for the type of carton to be constructed. The blank 10 consists of outer side panels 11, 12, 13 and 14, outside bottom panel 15, intermediate side panels 16 and 17, inside bottom panel 18 and inner side panels 19, 20, 21 and 22. The bottom panels 15 and 18 are attached to the outer side panels 11 and 13 along a longitudinal score line 23. The side panels 11, 12, 13 and 14 are attached along vertical score lines 24, 25 and 26. A score line 27 at one end of the blank defines a flap 28 which will be secured to the opposite end of the blank in forming the blank into a flat tube for shipment to customers. It will be understood that other forms of attachment or joint such as tape can be used. The intermediate side panels 16 and 17 are attached to the outside bottom panel 15 along the score lines 25 and 26 which are extended below the side panels. The inner side panels 19, 20, 21 and 22 are attached respectively to the side panels 11, 12, 13 and 14 along the score line 29. Extending outwardly from the score lines 24, 25 and 26 are slots 30, 31 and 32 which separate the inner panels 19, 20, 21 and 22 from each other.

The slots 30, 31 and 32 are so cut that the edge of one panel will match with the adjacent edge of the next panel. For example, the projection 31a of panel 20 will match with the indentation 31b of panel 19. In like manner the outer edges of panels 19 and 22 will likewise match when the blank is formed into a tube. The purpose of such matching will be more apparent from the description of the assembly of the blank to form a box.

After the blank has been formed into a tube (FIG. 2) it can be shipped flat to the customer, who will set it up into a box by forming the bottom and folding in the inner side panels. The bottom illustrated in the drawings can be completed by first folding in the inside bottom panel 18 (FIG. 3) so that it rests against the inner surface of panel 11. The intermediate bottom panels 16 and 17 are then folded so that they are flat against the inner face of outside bottom panel 15 after which such superimposed panels 15, 16 and 17 are folded so that they are flush with the bottom edges of the side panels (FIG. 4). The intermediate panels 16 and 17 are then folded upwardly to lie flush against the inner faces of side panels 12 and 14 after which the inside bottom panel is folded downward to lie against the inner face of the outside bottom panel 15, thus completing the formation of the bottom (FIG. 5). The bottom shown herein does not form part of the present invention and is merely one form of self-locking bottom which can be used in the box of the present invention. Other forms of self-locking bottoms can likewise be used. For example, the opposite flaps or panels can be provided with a tab and slot which can be interlocked. Although the bottom of a regular slotted carton could be used, it will be apparent that any such form of bottom formation, which is not self-locking, will require either stitching, gluing or other similar means to retain the flaps or panels of the bottom in position. Since no other equipment or device is necessary to assemble the box of the present invention, it will be seen that such other bottom formations are not desirable.

After the bottom has been formed, each of the inner side panels 19, 20, 21 and 22 are folded inwardly so that they lie flat against the inner faces of the side walls. In the blank illustrated panels 19 and 21 will overlie outer outer side panels 11 and 13 respectively and panels 20 and 22 will overlie intermediate side panels 16 and 17 respectively. However, if there is a bottom formation in which there are no intermediate side panels, panels 20 and 22 will overlie outer side panels 12 and 14. The widths of the slots 30, 31 and 32 and the slot between the inner side panels 19 and 22 is sufficient to compensate for the thickness of the assembled side panels but should provide for a tight fit in the corners when the inner side panels are folded into place. When such panels are pushed together at the corners the projections on the edge of one panel fit into the indentations of the adjacent panels. Since the slots are cut with matching scalloped projections and indentations, the mating and locking of adjacent projections and indentations is assured. It will be apparent that such projections and indentations can be made in various forms and shapes so long as they are matching. FIG. 8 illustrates a slot 33 with rectangular projections 33a and 33b. Circles, notches, triangles and the like or combinations thereof are merely examples of other forms.

Since the inner side panels lock along the side corners, such side panels do not have to extend to the bottom of the box. They can be any depth into the box without making the locks less effective and positive.

Handle portions may also be provided for the box as illustrated in the drawings. Hand holes 34 are die cut in the intermediate panels 16 and 17 and in the inner side panels 20 and 22. Hand holes 35 are also cut in the outer side panels 12 and 14 but flaps 35a are cut only on three sides and remain hinged along line 35b. This permits each flap 35a to be pushed through the holes 34 in the intermediate and inner side panels to provide a grip surface for the hand hole.

Thus among others, the several aforenoted objects and advantages are most effectively attained. Although a somewhat preferred embodiment of the invention has been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.

Claims

Having thus described the invention, what is claimed is:

1. A blank made from a generally rectangular sheet adapted for folding into a box having side walls and a bottom comprising outer side panels joined together along vertical score lines, the free edges of the end panels being adapted to be joined together to form the blank into a tube, and an inner side panel joined to each of the outer side panels along a longitudinal score line, said inner side panels being separated by slots extending outwardly from the vertical score lines, the adjacent edges of such slots having matching projections and indentations, whereby when the blank is formed into a box and the inner side panels are folded inwardly to lie flat against the inner faces of the walls the matching projections and indentations will mate and interlock the adjacent edges of the inner side panels together.

2. The blank of claim 1 in which the matching projections and indentations are generally rectangular in shape.

3. The blank of claim 1 in which the matching projections and indentations are generally scalloped in shape.

4. A box formed from a generally rectangular blank of sheet material cut, scored and folded into said box having side walls and a bottom comprising outer side panels joined together along vertical hinge lines to form a tube, and an inner side panel joined to each of the outer side panels along a longitudinal hinge line and folded inwardly to lie flat against the inner face of the side wall, the adjacent vertical edges of the inner panels having matching projections and indentations which mate to interlock such edges together.

5. The box of claim 4 in which the matching projections and indentations are generally rectangular in shape.

6. The box of claim 4 in which the matching projections and indentations are generally scalloped in shape.