GB2305651A

GB2305651A - Stackable cartons

Info

Publication number: GB2305651A
Application number: GB9519766A
Authority: GB
Inventors: Roy Douglas Paul Foden
Original assignee: ASSIDOMON PACKAGING UK Ltd
Current assignee: ASSIDOMON PACKAGING UK Ltd
Priority date: 1995-09-28
Filing date: 1995-09-28
Publication date: 1997-04-16
Anticipated expiration: 2015-09-28
Also published as: GB9519766D0; GB2305651B

Abstract

A carton is provided with roughened areas for frictional interengagement with like roughened areas of a neighbouring carton in a stack, in which the material 26,28,30 forming the carton is multiply punctured through its entire thickness at each roughened area, e.g. by pins 22, to produce upset regions 32 and intervening recesses 34.

Description

STACKABLE CARTONS This invention relates to cartons of for example corrugated board that can be stacked in layers, with means to resist relative movement of adjacent layers. United layers are useful in palletized and other loads to prevent the cartons from shifting in transit, as well as being generally useful for enhanced stack stability.

A known method of uniting layers is to apply strips of glue about 20 mm long in four places on the top of each carton. The next cartons placed on the stack then adhere to those below. A problem with this technique is in regulating the amount of glue and the positions at which it is applied, the latter varying depending upon the carton dimensions and stacking pattern. If the bonds between adjacent layers are too weak, the stack will be unstable; whereas if the bond is too strong the cartons cannot be pulled apart without tearing their outer liners.

Another method of uniting layers is to provide interlocks in the form of tabs extending from the cartons in one layer into recesses in the cartons of the adjacent layer. The cartons must be accurately placed to ensure proper location of the tabs in the recesses. With heavy carton contents, multiple layers of corrugated board may be required to form tabs and apertured cartons of sufficient strength, increasing the amount of material needed to form the cartons and restricting flexibility of carton design.

We have devised a simple yet effective alternative means for enhancing the stacking stability of a carton, in which the carton is provided with roughened areas (for example portions of its top and bottom panels) for frictional engagement with like roughened areas of a neighbouring carton in the stack.

Preferably, the roughened areas are produced by a stamping or pressing operation. The material forming the carton may be multiply punctured at each roughened area, to produce upset regions and intervening recesses. The stamping or pressing may be carried out simultaneously with a die-cutting operation to form a blank for the carton from stock material, the cutting die or roll preferably including an array of pins for puncturing the blank from the inside at each area and forming the upset regions. Thus the invention also extends to blanks for cartons having such roughened areas, and to a method and apparatus for making such blanks as set out in claims 5 - 7.

The invention and its preferred features will be better understood from the following description of illustrative embodiments, made with reference to the drawings in which: Figure 1 is a diagrammatic representation of a carton blank embodying the invention; Figure 2a is a plan view of a first pin block useful in carrying out the present invention; Figure 2b is a detail view of a portion of a carton blank and a second pin block useful in carrying out the present invention; and Figure 3 shows alternative pin cross-sections and arrangements.

The blank 10 of figure 1 comprises side panels 12, end flaps 14, a top panel 16 and a bottom panel 18. The top and bottom panels 16, 18 are each provided with six roughened areas 20, those of each panel 16, 18 being vertically aligned in the erected carton. When the cartons are stacked, the roughened areas on the top of one carton will frictionally engage the roughened areas on the bottom of the carton above to prevent relative sliding.

The roughened areas may be formed by patches of rough surfaced material secured to the blank, but are preferably produced from the blank material itself by any suitable stamping or pressing operation, for example by cooperating die parts attached to the die cutting press or roll used to cut the blanks from stock material. Particularly effective frictional engagement has been found to result from blanks which have been punctured from the inside to form the roughened areas using arrays of pins 22 cast into blocks 24 mounted on the cutting die or roll at the required locations.

The pins in figure 2a are abutted in a close packed array of seven columns alternately containing 9 and 8 pins each. The pins have a diameter of 3mm and a height of 4mm.

Figure 2b shows the pins 22 spaced apart to more clearly illustrate their effect upon the blank. The pins 22 in use pass through the inner liner 26 and fluting 28 of the blank to just puncture the outer liner 30, thereby producing upset regions 32 and intervening recesses 34. The upset regions 32 and recesses 34 of contacting roughened areas in a stack of cartons will interengage one another, frictionally resisting relative movement between carton layers.

The pins shown in figures 2a and 2b are circular in cross-section, but other shapes are possible. Figure 3 shows some examples: on the left is a close packed array of cruciform cross-sectioned pins and on the right a square array of v-cross-sectioned pins of varying orientation. Both types of pin shown in figure 3 will produce barbs or tangs upset from the outer liner of the blank to be engageable with corresponding barbs or tangs on a neighbouring stacked carton.

The blanks and cartons of the present invention are not significantly weakened by the formation of the roughened areas. Where the roughened areas are produced from the material of the blanks themselves, no additional raw materials are required and the extra manufacturing equipment needed is modest.

Claims

1. A carton provided with roughened areas for frictional interengagement with like roughened areas of a neighbouring carton in a stack.

2. A carton as claimed in claim 1 in which the roughened areas are produced by a stamping or pressing operation.

3. A carton as claimed in claim 2 in which the material forming the carton is multiply punctured at each roughened area, to produce upset regions and intervening recesses.

4. A blank for a carton as claimed in any preceding claim.

5. A method of forming a blank for a carton as claimed in claim 2 or 3 wherein the stamping or pressing operation is carried out simultaneously with a die cutting operation to form the blank from stock material.

6. A method as claimed in claim 5 wherein a cutting die or roll is used which includes an array of pins for puncturing the blank at each area and forming upset regions.

7. Apparatus for forming a blank for a carton as claimed in claim 1 or 2 comprising an array of pins for puncturing the blank at each area to form upset regions.

7. Apparatus for forming a blank for a carton as claimed in claim 2 or 3 comprising a die cutter having means for forming the roughened areas.

8. Apparatus for forming a blank for a carton as claimed in claim 2 or 3 comprising an array of pins for puncturing the blank at each area to form upset regions.

Amendments to the claims have been ffied as follows 1. A carton provided with roughened areas for frictional interengagement with like roughened areas of a neighbouring carton in a stack, in which the material forming the carton is multiply punctured through its entire thickness at each roughened area, to produce upset regions and intervening recesses.

3. A blank for a carton as claimed in any preceding claim.

4. A method of forming a blank for a carton as claimed in claim 2 wherein the stamping or pressing operation is carried out simultaneously with a die cutting operation to form the blank from stock material.

5. A method as claimed in claim 4 wherein a cutting die or roll is used which includes an array of pins for puncturing the blank at each area and forming upset regions.

6. Apparatus for forming a blank for a carton as claimed in claim 1 or 2 comprising a die cutter having means for forming the roughened areas.