Lined carton

Abstract

A paperboard carton is provided including a bottom panel, and side and end walls hinged thereto and corner flaps on certain of the walls overlapping portions of the adjoining walls to form areas of double thickness. A lining film of plastic or the like is adhered to the inner surface of the paperboard. One or more apertures are provided in the inner layer of the double thickness areas. The lining film extends through these apertures and is secured to the outer layer, thus securing the corner flaps in place.

Description

This invention relates to a lined carton and method of making the same and deals particularly with a simple carton having a liner film adhered to the inner surface thereof. The liner acts to hold the carton in its formed condition.

BACKGROUND OF THE INVENTION

In an application being simultaneously filed in the name of Lawrence Knoell a lining film is applied over the upper surface of the tray shaped carton, and suction is applied to the external walls of the tray, to draw the film into the tray and in close contact with the bottom and side walls thereof. This film may either be extruded directly over the cartons, or a plastic film may be heated while over the trays and drawn into the trays by suction applied to the outer surface of the various walls so as to form a continuous liner adhered to the porous paperboard to make the tray waterproof. The tray may or may not be provided with a hinged cover to which the partially molten film is secured.

Trays of this type are usually connected by corner flaps adhered or otherwise secured to opposed walls of the tray, forming areas of double thickness. While paperboard is normally porous to some extent, it is obviously more difficult to draw the film against the inner surface of the tray at the double thickness areas than through the remaining single thickness of the remainder of the tray. Usually, the trays are preformed, with the corner flaps hinged to the ends of two opposed walls and folded into surface contact with the remaining walls of the tray. It has been shown that if sufficient suction is applied to the exterior of the walls, the liner will conform very closely to the inner surfaces of the walls and be adhered thereto while the film is in its partially molten form.

SUMMARY OF THE INVENTION

It has been found that the operation of forming the tray can be simplified by merely plunging the flat blank into pockets on a conveyor, suitable means being provided for swinging the corner flaps on the two opposed walls against the other two walls. Then by providing apertures in the walls of the tray or corner flaps in the double thickness areas, the film will be drawn through the apertures, securing the corner flaps to the walls against which they lie.

Under normal conditions, the corner flaps on the two opposed walls are folded outwardly of the remaining opposed walls to provide a stronger corner structure. In such an event, the apertures are provided in the portions of the walls over which the corner flaps extend. As a result, the vacuum applied to the exterior walls must pass through only one layer of paperboard in the area outwardly of the apertures so that the film is drawn through the apertures and against the outer layer of the double thickness area. Obviously, if the corner flaps are folded inwardly of the walls, the apertures are formed in the corner flaps, and are drawn against the opposed container walls in the areas of double thickness formed by the corner flaps.

These and other objects and novel features of the present invention will be more clearly and fully set forth in the following specification and claims .

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the lined tray.

FIG. 2 is a sectional view through a section of the apertures in the double thickness area, the position of the section being indicated by the line 2--2 of FIG. 1.

FIG. 3 is a sectional view through one of the double thickness areas showing the manner in which the lining film is drawn through the apertures, the position of the section being indicated by the line 3--3 of FIG. 2.

FIG. 4 is a diagrammatic view of the blank from which the tray is formed.

FIG. 5 is a diagrammatic view showing the manner in which the film is drawn by suction into the container for lining the same.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawings, the carton is formed as an open-top tray in order to show the simplest form of construction. Obviously, a cover may be hingedly connected to one of the walls, and flanges may be hingedly secured to others of the walls if it is so desired. Furthermore, while a particular arrangement of apertures is illustrated, this specific arrangement is merely a matter of choice, it only being necessary that the apertures extend through the double thickness areas of the tray formed by the corner flaps. Also, while the tray is illustrated as having vertical walls, it should be understood that trays having upwardly and outwardly inclined walls could also be used by modifying the shape of the walls and the corner flaps.

The tray A is formed of the blank illustrated in FIG. 4 of the drawings. As indicated, it includes a generally rectangular bottom panel 11 which is foldably connected along parallel fold lines 12 to side walls 13. The bottom panel 11 is also connected along fold lines 14 which are at right angles to the fold lines 12 to end walls 15. The side walls 13 are hingedly connected at their ends by fold lines 16 to corner flaps 17.

In the normal formation of the carton, the side and end walls 13 and 15 are folded upwardly to right angular relation with the bottom panel 10, and the corner flaps 17 are folded outwardly of the end walls 15, as is indicated in FIG. 1 of the drawings. As previously stated, the tray like carton may also include a cover hingedly connected to one of the side walls 13, and may include flanges hingedly connected to the upper edges of certain of the walls, such as the end walls 15.

In the arrangement illustrated, a series of three apertures 19 extend through the end walls 15 in the area which will be normally covered by the corner flaps 17. Also in the arrangement illustrated, the apertures are arranged with two of the three apertures at each corner positioned near the end of the double thickness area and a third aperture near the side extremity of the end walls. Obviously, the shape of the apertures may be varied, and the apertures may be square or any other desired shape. Furthermore, in place of having three apertures, a single larger area may be provided if desired.

In the application being simultaneously filed in the name of Lawrence Knoell, a carton is disclosed having a liner formed of plastic film or the like which may be heated to partially molten form, and drawn into the carton to line the entire interior thereof. As a result, the liner is continuous, and the carton is capable of holding water or other liquid without leaking. In this previous structure, the cartons are usually preformed by adhering or otherwise securing the corner flaps to the adjoining walls. I have found that this preforming operation may be avoided by drawing portions of the resilient film through the apertures and into contact with the surface of the outer layer of the double thickness area. The film has a tendency to adhere to the surface of the paperboard, and by drawing the film through the apertures and against the inner surface of the outer layer of the double thickness area, the corner flaps may be held in place so that the carton remains in erected form once the film has been drawn into the open topped carton. FIG. 2 shows the wall 13 and bottom wall 11 of the carton which is formed of paperboard. Paperboard is always somewhat porous unless it is specifically formulated so as to avoid being porous. In other words, the form of paperboard normally used to produce folding cartons and the like is not air tight, and air may be drawn through the fibrous board unless it is coated with an air pervious material. Accordingly, if vacuum is applied to the outer surfaces of the wall panels, a suction may be created within the open topped carton which will draw a partially molten plastic film against the inner surface of the carton wall as indicated in FIG. 2. The film acting as the carton liner is indicated by the numeral 20.

FIG. 3 of the drawings is a sectional view through the double thickness area of the carton and through two of the spaced apertures 19. As indicated, portions 21 of the liner have been drawn through the apertures 19 and into contact with the inner surface of the corner flaps 17 so as to secure the corner flaps to the wall 15.

This step saves the separate operation of gluing or otherwise securing the corner flaps in face contact with two opposed walls of the carton.

FIG. 5 is a very diagrammatic view showing the manner in which this may be accomplished. The numeral 22 indicates a portion of the upper reach of an endless conveyor belt having a series of foraminous pockets in spaced relation supported by the belt 22. As the conveyor belt 22 moves in the direction of the arrow 24, it passes beneath a suitable hopper 25 which includes some sort of means for depositing a carton blank upon the conveyor belt 12 overlying each pocket 23. As the pocket 23 moves to the right, a plunger 26 supported by a reciprocable plunger arm 27 forms the flat blank into the foraminous pocket 23, there being means on the belt 22 to fold the corner flaps 17 into surface contact with the end walls 15. Such a means is not indicated in the drawings, but is well known in the art. One such carton forming means capable of erecting the side and end walls from the bottom panel, and folding the corner flaps into right angular relation to the walls from which they are hinged is shown in U.S. Pat. No. 2,516,624 issued July 27, 1950 to Reynolds Guyer.

As the conveyor belt 22 keeps moving to the right, the film F moves into overlying relation with the cartons in the pockets 23. The film F may be extruded directly over the cartons as indicated in the Knoell application above referred to, or may be drawn from a supply roll, and heated by heating means indicated at 29. The foraminous pockets 23 move through a vacuum chamber 30 which applies vacuum to the outer surfaces of the open topped carton, and draws the film into the cartons to adhere to the various walls thereof and form a unitary liner.

During the movement of the carton through the vacuum chamber 30, the vacuum draws air through the single thickness portions of the carton more readily than the portions which are of double thickness, as will be obvious. Accordingly, by providing the apertures 17 in the inner layer of the double thickness areas, the vacuum will be drawn through the outer layer in the areas outwardly of the apertures. As a result, the film will adhere to the corner flaps 17 and attach them to the end walls 15 virtually as effectively as the corner flaps would be adhered by use of an adhesive. Thus the step of separately erecting and gluing the corner flaps in place is eliminated, and the corner flaps are attached to the end walls at the same time the film is attached to the interior of the carton.

This system also has the effect of better securing the lining film to the entire inner surface of the carton. In following the method described in the co-pending application above referred to, it has been found that the film sometimes will not adhere to the inner surface of the double thickness areas of the carton. Such double thickness areas are virtually essential if the corners are to be formed by corner flaps. By providing apertures in the double thickness areas, the film is drawn more closely to the surface of the double thickness areas, and a more complete adhesion of the film to the interior of the carton is likely to result.

In accordance with the Patent Statutes, I have described the principles of construction and operation of my improvement in LINED CARTON; and while I have endeavored to set forth the best embodiment thereof, I desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of my invention.

Claims

I claim:

1. A paperboard carton corner in combination with a carton having a base panel, a pair of walls hinged to the base panel, and a corner flap hinged to one wall and overlapping the other wall to form an area of double thickness, the inner layer of the double thickness area having an aperture therethrough, and a plastic liner film attached to the inner surface of said paperboard, said film extending through said aperture and secured to the outer layer of said double thickness area to hold the overlapping portions in overlapping relation.

2. The structure of claim 1 and in which said inner layer includes a plurality of apertures through which said film extends.

3. The structure of claim 1 and in which said corner flap comprises the outer layer of said double thickness area.

4. A carton of paperboard and the like including a rectangular bottom panel, side and end wall panels hingedly secured thereto, and corner flaps secured to two opposed of said walls overlapping the adjoining walls to form areas of double thickness,

the inner layer of said double thickness areas having at least one aperture therein,

a liner of plastic film secured to the wall panels and bottom panel,

portions of said liner extending through said apertures and secured to the outer layer to secure said double thickness areas in overlapping relation.

5. The structure of claim 4 and in which said corner flaps form the outer layer of said double thickness area.

6. The structure of claim 4 and in which said inner layer of said double thickness area includes a plurality of apertures in each double thickness area.