EP0007215B1

EP0007215B1 - Carton erecting apparatus

Info

Publication number: EP0007215B1
Application number: EP79301316A
Authority: EP
Inventors: David Hayward; Jean-Pierre Guays
Original assignee: PAKFAST Ltd
Current assignee: PAKFAST Ltd
Priority date: 1978-07-07
Filing date: 1979-07-06
Publication date: 1983-12-28
Also published as: DE2966508D1; EP0007215A1; GB2024705A; IL57724A0; IL57724A

Description

Technical Field

This invention relates to an apparatus and also a unitary device for erecting portions or the whole of carton blanks to make cartons or boxes of polygonal cross-section.

Background Art

Carton blanks are usually of planar form and have various crease lines and cut lines arranged so that portions of the carton can be erected with respect to other portions during passage of the carton in one direction through the apparatus for forming the carton from the blank. Apparatus for the formation of cartons from planar blanks is generally of a complicated structure and includes a large number of moving parts designed to erect various portions of the blank with respect to one another at the aforementioned crease and cut lines. The complexity of known machines increases substantially when it is desired to provide a single machine for making a number of different sizes of cartons from different carton blanks to include means for securing the cartons together in their finished state. British Patent Specifications GB-A-936 743 and GB-A-1,359,498 describe such complex machines.
Additionally, US Patent Specification US-A-3,611,885 discloses, firstly, an apparatus for erecting a carton from a carton blank which includes a substantially polygonal base and, in at least one corner area of the base, two side walls joined to the base along crease lines and extending away from the corner area and at least one uniting portion, parts of one or both of the side walls and the or each uniting portion overlapping each other in the erected condition of the blank for holding the side walls erect. Such known apparatus includes a plurality of devices for erecting the side walls of the carton, the devices comprising erecting surfaces for the side walls and the or each uniting portion arranged to be fixed in relation to each other, the side wall erecting surfaces extending at an angle to one another which corresponds to the angle between the associated side walls in the erected condition of the blank, a forming mandrel arranged to move a carton blank past the erecting surfaces, in order to erect the side walls and the or each uniting portion, and respective side wall support and guide surfaces which are located downstream with respect to the movement of the mandrel and in line with the corresponding side wall erecting surfaces associated with each device, which serve to hold the erected parts of the or each corner portion of the carton in position against the forming mandrel, and which are arranged so as to apply pressure against the mandrel with the overlapping parts of the carton corner portion therebetween, whereby an adhesive previously applied to such overlapping parts can be caused to be effective.
Secondly, this US Patent Specification US-A-3,611,885 discloses a unitary device for erecting a corner portion of a carton of the type described above, which device including erecting surfaces, for the side walls and the or each uniting portion arranged to be fixed in relation to one another, comprising two side wall erecting surfaces extending at an angle to one another which corresponds to the angle between the associated side walls in the erected condition of the carton, and two side wall support and guide surfaces being associated with and arranged downstream from a corresponding one of the side wall erecting surfaces, with regard to the path of movement of a carton blank, and one of the support and guide surfaces being arranged to apply pressure, in the erected condition of the carton, to overlapping parts of the corner portion, to which an adhesive has previously been applied, in order to effect adhesion together of the overlapping parts of the corner portion of the carton.
A disadvantage associated with the known apparatus described above, and as disclosed in US Patent Specification US-A-3,611,885, is that the apparatus cannot be readily adapted to cope with the erection of blanks into cartons of different sizes. Also, this type of apparatus cannot be utilised to form, say, only one or two corners of a polygonal carton, wherein such a corner or corners has or have the parts of the adjacent side walls and associated uniting portion overlapping each other in the erected condition of the blank.

Disclosure of the Invention

Accordingly, the present invention sets out to overcome these disadvantages by providing an apparatus of the type defined above, wherein the devices for erecting the side walls of the carton are formed as independent devices for erecting the respective corner portions of the carton, wherein the side wall erecting surfaces of the devices have such a longitudinal extent as to contact only the relatively short parts of the associated side walls lying adjacent the or each corner area of the blank base, and wherein the support and guide surfaces for the overlapping ones of the erected parts of the carton corner portion are movable towards and away from the mandrel, in a direction generally perpendicular to the direction of movement of the mandrel, to apply pressure to the mandrel.
Similarly, and in relation to a unitary device in accordance with the invention, such a device can be adjusted to accommodate different sizes of blank and can be used to erect, say, only one corner, as desired. Thus, a unitary device in accordance with the invention has erecting surfaces which are of such a longitudinal extent that they contact only the relatively short parts of the associated side walls lying adjacent the corner area of the blank base.
In such a unitary device, one of the support and guide surfaces may be movable by a piston and cylinder unit for applying the pressure to the overlapping parts of the respective corner portion of the erected carton.
In use of the apparatus in accordance with the invention, the mandrel has a cross-section corresponding to the base portion of the carton blank and is caused to pass into contact with this base portion and so cause the entire carton blank to engage by way of its side wall and uniting portions with corresponding erecting surfaces, which cooperate with the mandrel to cause the side wall and uniting portions to attain their respective positions in the erected condition of the carton.
The side wall support and guide surfaces for the overlapping ones of the erected parts of the corner portion are preferably movable towards and away from the mandrel, that is, in a direction generally perpendicular to the direction of movement of the mandrel, under the action of a piston and cylinder unit, e.g. a pneumatically-operated pressure cylinder, whereby an adhesive previously applied to such overlapping parts, for example a cold-setting pressure-sensitive adhesive, such as PVA adhesive, can be caused to be effective when the pressure cylinder is actuated to apply the support and guide surfaces under substantial pressure against the mandrel, with the overlapping parts of the corner portion of the carton therebetween. The pneumatic or other piston and cylinder unit and the support and guide surfaces or a pressure plate supporting them can be an integral part of the erecting device. Preferably, the erecting surfaces are provided on exchangeable parts of the apparatus.
The apparatus may easily be provided with means for applying an adhesive, such as a cold-setting pressure-sensitive adhesive, to one or more of the surfaces of the carton blank which are overlapped at the end of the erection process.
Also, the invention is able to provide a functionally efficient apparatus which is flexible and adaptable and which has a minimum number of parts which move during operation thereof.

Brief Description of Drawings

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a front view of a mobile apparatus for erecting cartons from carton blanks in accordance with the present invention;
Figure 2 is an end view of the apparatus of Figure 1;
Figure 3 is a top plan view of a device, which is included in the apparatus of Figure 1, for erecting a corner portion of a carton;
Figure 4 is a front view and Figure 5 is an end view of the device of Figure 3;
Figure 6 is a plan of a carton blank suitable for use in the apparatus illustrated in Figures 1 to 5;
Figures 7, 8 and 9 illustrate other forms of carton blanks or portions of blanks and are provided to show how the corner portion erecting surfaces in apparatus embodying this invention may be utilised to form cartons from blanks of different configurations;
Figure 10 is a top plan view of part of a modified form of the apparatus in accordance with the invention which is shown in Figures 1 to 5; and
Figure 11 is a top plan view of part of a further modified form of the apparatus in accordance with the invention which is shown in Figures 1 to 5.

The apparatus embodying the invention shown in Figures 1 to 5 of the accompanying drawings includes a base frame 1 supported on wheels 2 and carrying upright frame members 3 and top frame members 4 which are secured together to provide a rigid framework. Further frame members 5 are secured between the upright frame members 3 at approximately a mid-height position and these frame members 5 slidably support carton blank guides 6 which have variably positionable end stops 6a. Also, the carton blank guides 6 can be moved towards and away from one another along the frame members 5, so that different widths of blanks as well as different lengths of blanks can be fed into the apparatus and correctly positioned therein.
A piston and cylinder unit 7 is secured to the top frame members 4 and the piston of this unit 7 is guided vertically and, at its lower end, supports a forming mandrel 8, in an easily detachable manner. The dimensions of the mandrel 8 correspond to the dimensions of a carton to be erected by the apparatus, in a particular configuration of the movable elements of the apparatus. The mandrel 8 is movable from a position located above the plane defined by the guides 6 to a position substantially below this plane, in which the carton has been erected from the blank.
Four corner portion forming devices or units 9 are mounted below the plane defined by the blank guides 6 and are arranged in pairs. The corner units 9 of each pair are slidable towards and away from each other on channel members 10 and can be locked in any desired position on the channel members 10. The channel members 10 are themselves movable towards and away from each other on cross members 11 secured to the upright frame members 3 and can be locked in any desired position thereon.
One of the corner portion forming units 9 is illustrated in greater detail in Figures 3, 4 and 5.
A mounting plate 20 is provided with slots 21 for receiving mounting bolts for securing the corner unit to a channel member 10. A pneumatic piston and cylinder unit 22 is secured to the mounting plate on one side thereof and the piston rod 23 of the unit 22 extends through the plate and has its end secured to a pressure plate 24 which is recipro- cable perpendicularly to the mounting plate 20 under the action of the piston and cylinder unit 22.
A support plate 25 is secured to the upper edges of the mounting plate 20 and is curved inwardly with respect to the apparatus and the mandrel path from the mounting plate 20 and carries at its free end a corner forming assembly 26 which comprises short side wall erecting surfaces 27 and 28 which are of convex form seen in the direction of the mandrel 8 and which have upper surfaces lying in a common plane which is generally parallel to the plane defined by the carton guides 6. The side wall erecting surfaces 27 and 28 are arranged perpendicularly to each other and the side wall erecting surface 28 is arranged so as to be a substantially tangential continuation of the pressure plate 24. The other side wall erecting surface 27 is arranged so that a vertical side wall support and guide surface 29 of a side wall supporting member 30 is at a tangent to the surface 27. The member 30 is supported on the corner forming assembly 26 and depends therefrom.
A corner flap erecting member 31 is mounted on the corner forming assembly 26 so as to have its upper surface above the plane defined by the upper portions of the erecting surfaces 27 and 28 and in a position outwardly of the path of movement of the mandrel 8. The corner flap erecting member 31 also has its upper surface convex with respect to the direction of movement of the mandrel 8 on erection of a carton.
The corner portion forming units 9 used in the apparatus are of two types, a left hand unit and a right hand unit, and the pairs of each type are arranged in the apparatus so that there are a pair of pressure plates 24 and a pair of vertical support and guide surfaces 29 in opposition to each other at each side of the apparatus. The distance between the vertical surfaces 29 is equal to the shorter dimension of the rectangular base 40 of the carton blank plus twice the thickness of the blank material and the distance between the pressure plates 24 is equal to the sum of the longer dimension of the base 40 and four times the thickness of the blank material.
A blank suitable for use with the apparatus of this invention described above is shown in Figure 6. The blank is of rectangular form and has the above-mentioned rectangular base 40 defined between opposite pairs 41 and 42 of crease lines. Side wall pairs 43 and 44 are se-cured to the base 40 along respective crease lines 41 and 42. The side walls 44 have a length corresponding to the associated dimension of the base 40, while the side walls 43 are extended by uniting portions in the form of corner flaps 45 which are separated from the associated side walls to which they are to be secured by an adhesive by cut lines 46.
In construction of a carton from the blank shown in Figure 6, the mandrel 8, mounted on the end of the piston rod of the piston and cylinder unit 7, has external dimensions corresponding to the base 40 and a height at least equal to the height of the side walls 43 and 44. Initially the mandrel 8 is located above the plane defined by the blank guides 6 and the blank is slid into the apparatus along the blank guides 6, the side walls 44 having their edges supported on the blank guides 6, until the corner flaps 45 of the uniting portion contact the end stops 6a.
The mandrel 8 is lowered by operation of the piston and cylinder unit 7 into contact with the blank and causes the blank to spring off the blank guides 6 and fall on to the upper surfaces of the corner flap erecting members 31. Further lowering of the mandrel 8 causes the remainder of the blank and in particular the base 40 and the connected side walls 44 to be lowered with respect to the corner flaps 45. On further lowering of the mandrel 8, the erecting surfaces 28 and 27 engage the side walls 43 and 44 and erection of these side walls commences. By virtue of the initial erection of the corner flaps 45, erection of the side walls 43 causes the corner flaps 45 to move into engagement with the inner surfaces of the side walls 44 and to be caused to rotate inwardly with respect to the side walls 43 to the erect position shown in Figure 3 of the drawings. When the carton has been fully erected, the mandrel 8 still lies within the erected carton. The mandrel 8 is held in this position while the piston and cylinder units 22 of all the corner forming assemblies 26 are operated to cause the associated pressure plates 24 to move inwardly to press the corner flaps 45 and the associated side walls 43 together, and against the mandrel 8 and to be secured by adhesive, which may have been applied to the carton blank prior to its insertion in the apparatus or to the carton blank during its passage through the apparatus by means (not shown) and located on one or more of the contacting overlapping surfaces of the side walls 43 and the corner flaps 45. Preferably, a cold-setting contact adhesive is used. Thus, the pressure need only be applied for a fraction of a second in order to ensure securement of the side walls 43 to the corner flaps 45 and so complete erection of the carton.
The mandrel 8 may now be further lowered, in order to cause the finished carton to pass completely through the corner forming assemblies 26, before the mandrel 8 is withdrawn to its initial position above the blank guides 6. Alternatively, the mandrel 8 may be withdrawn directly from the position in which pressure was applied and other suitable means may be used to eject the finished carton. For example, the next carton entering the apparatus may be used to displace the previous carton.
The apparatus illustrated in Figures 1 to 5 is particularly designed to erect a carton from a blank of the type shown in Figure 6. However, the present invention is not limited to a corner portion forming device of the type shown in these drawings and, by way of example, further types of carton blank are illustrated in Figures 7, 8 and 9 and a brief description now follows of the corner portion forming devices which might be utilised to erect blanks of the kinds shown in Figures 7, 8 and 9 and which could be utilised within the basic apparatus described with reference to Figures 1 and 2.
In Figure 7, a blank is shown for forming a triangular carton having only two erected sides. The carton blank has a base 50 of equilateral form and two side walls 51 and 52 extending away from one corner portion of the blank. A corner flap or uniting portion 53 is secured to the side wall 51 by a suitable crease line in the corner area. A corner portion forming device in accordance with the present invention for forming or erecting a blank as shown in Figure 7 into a carton would comprise side wall erecting surfaces arranged at 60° to each other and having a length approximately equal to the length of the uniting portion 53 and would incorporate a pneumatic pressure piston and cylinder unit on a mounting plate which also supports the erecting surfaces for the side walls and the corner flap or uniting portion 53 and arranged so that the piston and cylinder unit lies below the erecting surface for the side wall 52. Apparatus in accordance with the present invention would require only one such corner portion forming device.
In the carton blank shown in Figure 8, the corner of an otherwise rectangular base 60 is formed as a diagonal and a corner flap 61 is secured to the base 60 along a crease line 62 on this diagonal. Side walls 63 and 64 are not formed with any uniting portions themselves, but the corner flap 61 has two ears 65 and 66 joined to the corner flap 61 by crease lines 67 and 68. A device for forming the corner portion of a carton from such a blank would incorporate side wall erecting surfaces arranged at right-angles with respect to one another and joined to each end of a corner flap erecting surface extending between the side wall erecting surfaces. Additional erecting surfaces for the ears 65 and 66 would also be provided. In this case, it would be necessary to provide two pressure plates for applying the ears 65 and 66 to the side walls 63 and 64. However, once again, all these parts can be included in a unitary assembly which can be made movable over the framework of the apparatus, including a plurality of such unitary devices, so as to allow for the creation of a number of boxes of different sizes.
In Figure 9, a corner portion of a blank is shown which has a base 70 of generally polygonal form, but in which the base 70 has a cut and rounded corner 71. Side walls 72 and 73 extend along the straight sides of the base 70 and are attached thereto by suitable crease lines. Each side wall 72 and 73 has an extension in the form of a uniting portion or corner flap 74 or 75 secured thereto by way of a crease line and extending further in the same direction as each of the respective side walls themselves. The uniting portions or corner flaps 74 and 75 are cut from the basic rectangular shape of the blank defined by the outside cut edges of the side walls 72 and 73 and are chosen to be of such a length that their ends overlap one another in the erected form of the blank, but do not overlap the side walls 72 or 73. A suitable device for forming the corner portion of this blank and embodying the present invention incorporates erecting surfaces for the side walls 72 and 73 arranged in the same way as in the device for erecting the blank of Figure 8. However, in the case of the device for erecting the blank of Figure 9, the erecting surface for the uniting portions or corner flaps 74 and 75 has a curved form corresponding to the edge of the corner 71 of the base 70. Pressure is applied by means of a curved plate designed to cooperate with a curved corner of the mandrel and movable towards and away from the mandrel and overlapping parts of the corner flaps 74 75.
Figure 10 illustrates a modified form of the apparatus shown in Figures 1 to 5. In this Figure, only one pair of corner forming units and the associated components of the apparatus are shown. Two corner forming units 109 are supported on a channel member 110 by U-bolts 111. Each of the corner units 109 is similar to the corner forming assembly 26 described with reference to Figures 1 to 5, but the pressure plates and the pneumatic piston and cylinder units are not parts of the corner forming units themselves. In this modified apparatus, a piston and cylinder unit 112 is mounted independently on the channel member 110 by U-bolts 113 and the piston and cylinder unit 112 carries a pressure plate 114, pivotally mounted at 115, on the end of its piston rod 116. The pressure plate 114 is of a length so as to extend below the side wall erecting surfaces in the corner forming units 109 and to apply pressure to the overlapping portions of the side walls and the uniting portions of the corner area of a carton being erected. The corner forming units 109 can be moved towards and away from one another so as to be able to accommodate different widths of carton blank and, moreover, the corresponding channel members 110 can be moved towards and away from one another so as to accommodate different lengths of carton blank. The pressure plate 114 can be made of an overall length such that it is usable in all dispositions of the corner units 109. The modified apparatus illustrated in Figure 10 is operated in substantially the same way as the apparatus fully illustrated in Figures 1 to 5.
In some cases, it is desirable to be able to manufacture cartons having a lid from a one- piece blank. This can present problems as regards the size of apparatus, however, because the lid, in an apparatus of the kind shown in Figures 1 to 5, has to pass completely through the corner forming units 9 before it can be removed laterally from the apparatus.
Figure 11 illustrates a modified corner forming unit which allows the carton to be withdrawn from the apparatus immediately after adhesion of the overlapping portions of the erected carton to one another.
In a modified apparatus illustrated in Figure 11, a carton forming unit 200 is mounted on a supporting channel member 201 by U-bolts 202 which are clamped on to a mounting plate 203. The mounting plate 203 is welded to a sub-plate 204 which carries a side wall erecting surface 205, which corresponds to the side wall erecting surface 28 of Figures 1 to 5. Arranged immediately below the side wall erecting surface 205 is a pressure plate 206, which is mounted on the end of the piston rod of a pressure piston and cylinder unit 207, also mounted on mounting plate 203. A further side wall erecting surface 208, corresponding to the side wall erecting surface 27 of the apparatus of Figures 1 to 5 and including a portion 209 corresponding to the corner flap erecting surface 31 of the apparatus of Figures 1 to 5, is mounted at 210 upon a mounting strut 211, so as to be pivotally movable about a vertical axis through the pivot point 210 from the position shown in Figure 11 to a position in which it extends substantially colinearly with the erecting surface 205. A further piston and cylinder unit 212 has its piston rod 213 pivotally connected at 214 to the erecting surface 208 and the cylinder unit 212 is itself pivotally connected at 215 to a support plate 216 secured to the mounting plate 203.
In use of the modified apparatus of Figures 1 to 5 shown in Figure 11, the carton is erected in the manner already described with respect to Figures 1 to 5, with the apparatus in the position shown in Figure 11. Once the adhesive has been caused to be effective the cylinder unit 212 is operated to cause the erecting surface 208 to pivot about its pivot point 210 and the corresponding cylinder unit on the opposing corner unit on the other side of the machine is similarly operated, so that the erecting surfaces 208 are swung away from the position shown in Figure 11 to provide for free lateral discharge of the carton and its attached lid, which stands substantially vertical, from the apparatus. Thereafter, the cylinder units 212 are reactivated to return the erecting surfaces 208 to the position shown in Figure 11.

Industrial Applicability

Because of the structural simplicity of the apparatus of the invention described above, it is possible to construct it with a mobility capability by the provision of the carrying wheels 2. This enables the apparatus of the invention to have wide-ranging use in packaging processes and particularly where the location of the source of the product varies with time, as in the agricultural and horticultural fields.

Claims

1. An apparatus for erecting a carton from a carton blank which includes a substantially polygonal base (40) and, in at least one corner area of the base (40), two side walls (43, 44) joined to the base (40) along respective crease lines (41, 42) and extending away from the corner area and at least one uniting portion (45), parts of one or both of the side walls (43, 44) and the or each uniting portion (45) overlapping each other in the erected condition of the blank for holding the side walls (43, 44) erect, the apparatus including a plurality of devices (9) for erecting the side walls (43, 44) of the carton, said devices (9) comprising erecting surfaces (27, 28) for the side walls (43, 44) and the or each uniting portion (45) arranged to be fixed in relation to each other, the side wall erecting surfaces (27, 28) extending at an angle to one another which corresponds to the angle between the associated side walls (43, 44) in the erected condition of the carton, a forming mandrel (8) arranged to move a carton blank past the erecting surfaces (27, 28) in order to erect the side walls (43, 44) and the or each uniting portion (45), and respective side wall support and guide surfaces (29) which are located downstream with respect to the movement of the mandrel (8) and in line with the corresponding side wall erecting surfaces (27, 28) associated with each device (9), which serve to hold the erected parts (43, 44, 45) of the or each corner portion of the carton in position against the forming mandrel (8), and which are arranged so as to apply pressure against the mandrel (8) with the overlapping parts (43, 44, 45) of the corner portion of the carton therebetween, whereby an adhesive previously applied to such overlapping parts can be caused to be effective, wherein the devices (9) for erecting the side walls (43, 44) of the carton are formed as independent devices (9) for erecting the respective corner portions of the carton, wherein the side wall erecting surfaces (27, 28) of the devices (9) have such a longitudinal extent as to contact only the relatively short parts of the associated side walls (43, 44) lying adjacent the or each corner area of the base (49), and wherein the support and guide surfaces (29) for the overlapping ones of the erected parts (43, 44, 45) of the corner portion of the carton are movable towards and away from the mandrel (8), in a direction generally perpendicular to the direction of movement of the mandrel (8), to apply pressure to the mandrel (8).

2. An apparatus according to claim 1, wherein a piston and cylinder unit (22) is provided for effecting movement of the side wall support and guide surfaces (29).

3. An apparatus according to claim 2, wherein the piston and cylinder unit (22) and the support and guide surfaces (29) for one such corner area of the blank base (40) are formed as a unitary assembly with the erecting device (9) for the corresponding corner portion of the carton.

4. An apparatus according to claim 1 or 2, wherein the side wall support and guide surfaces (29) for overlapping ones of the erected parts (43, 44, 45) of adjacent corner portions of the carton are part of a single pressure plate (24).

5. An apparatus according to any of claims 1 to 4, wherein the independent devices (9) are movable on guide members (10) towards and away from one another and the size of the mandrel (8) may be changed so that the apparatus can be adapted for the erection of cartons of different sizes from carton blanks of different sizes.

6. An apparatus according to any of claims 1 to 5, wherein the erecting surfaces (27, 28) are provided on exchangeable parts of the apparatus.

7. An apparatus according to any of claims 1 to 6, provided with means for applying an adhesive such as a cold-setting pressure-sensitive adhesive, to one or more of the surfaces of the carton blank which are overlapped at the end of the erection process.

8. A unitary device (9) for erecting a corner portion of a carton from a carton blank including a polygonal base (40), two side walls (43, 44) joined to the base (40) along respective crease lines (41, 42) and extending away from a corner area of the base (40) and at least one uniting portion (45) in the corner area, parts of the side walls (43, 44) and the or each uniting portion (45) overlapping one another in the erected condition of the blank for holding the side walls (43, 44) erect, the device including erecting surfaces (27, 28), for the side walls (43, 44) and the or each uniting portion (45) arranged to be fixed in relation to one another, comprising two side wall erecting surfaces (27, 28) extending at an angle to one another which corresponds to the angle between the associated side walls (43, 44) in the erected condition of the carton, and two side wall support and guide surfaces (29) for holding the side walls (43, 44) and their uniting portions (45) erect, each of these support and guide surfaces (29) being associated with and arranged downstream from a corresponding one of the side wall erecting surfaces (27, 28), with regard to the path of movement of a carton blank, and one of the support and guide surfaces (29) being arranged to apply pressure, in the erected condition of the carton, to overlapping parts (43, 44, 45) of the corner portion, to which an adhesive has previously been applied, in order to effect adhesion together of the overlapping parts (43, 44, 45) of the corner portion of the carton, wherein the erecting surfaces (27, 28) have such a longitudinal extent as to contact only the relatively short parts of the associated side walls (43, 44) lying adjacent the corner area of the blank base (40).

9. A unitary device (9) according to claim 8, wherein said one of the support and guide surfaces (29) is movable by a piston and cylinder unit (22) for applying said pressure to the overlapping parts (43, 44, 45) of said corner portion of the erected carton.

10. A unitary device (9) according to claim 9, wherein the piston and cylinder unit (22) is a pneumatically-operated piston and cylinder unit.