WO1995011831A1

WO1995011831A1 - Apparatus for closing cartons

Info

Publication number: WO1995011831A1
Application number: PCT/GB1994/002346
Authority: WO
Inventors: Jeffrey Kenneth Sturgess
Original assignee: Field Group Plc
Priority date: 1993-10-25
Filing date: 1994-10-25
Publication date: 1995-05-04
Also published as: AU7997494A; GB9608494D0; GB2297305A; GB2297305B

Abstract

Apparatus for closing the tops of cartons of the kind described, comprising conveyor means (21-24) for conveying such cartons along a path of movement, first means (30; 202) for acting on said second pair of side walls (2) of each carton to make them outwardly concave, second means (35) for moving the said wing flaps (6) outwardly and downwardly towards the said over-centre positions thereof, and third means (43; 143; 150) for moving the said wing flaps downwardly and inwardly, past their said over-centre positions, to their closed positions.

Description

"Apparatus for closing cartons"

This invention relates to apparatus for closing cartons made of cardboard or similar lightweight foldable sheet material, in particular such cartons which are of box form having four side walls and a top closure, the top closure being provided by closure flaps on a first opposite pair of said side walls which are foldable inwardly and downwardly to close the top of the container, and wing flaps on the second opposite pair of side walls which are foldable outwardly and downwardly and are connected to the said closure flaps so that their downward folding is against a resistance which increases until they have passed an over-centre position in line with the upper edges of said second side walls and then reduces as they are folded further downwardly and inwardly, so that once the said over-centre position is passed the wing flaps are biased naturally towards closed positions adjoining said second side walls, and are thereby held in their closed positions. Such a container is that referred to hereinafter as being "of the kind described" . An embodiment of such a carton is illustrated in Figures 1 to 3 of the accompanying drawings. This carton, of box form, has a first pair of opposite side walls 1, a second pair of opposite side walls 2, top closure flaps 3 and 4 hinged to the side walls, one of which closure flaps carries a tear strip 5, and wing flaps 6 hinged to the side walls 2, the wing flaps be: connected to the top closure flaps along hinge lines "/ . Each of the side walls 2 is formed with a vertical central crease line 8 which extends upwardly through the centre of the associated wing flap 6 and, in the downward direction, splits into two crease lines 9 which extend to the respective bottom corners of the side wall. This arrangement of crease lines enables the walls 2 to be made slightly concave by pressing them inwardly, which helps to maintain the wing flaps 6 in their closed positions. Another pair of oblique crease lines 10 in the wing flaps 6 enable the flaps to be folded in the manner shown in Figures 2 and 3 during closure of the carton.

Viewed from one aspect the present invention provides apparatus for closing the tops of cartons of the kind described, comprising conveyor means for conveying such cartons along a path of movement, first means for acting on the said second pair of side walls of each carton to make them outwardly concave, second means for moving the said wing flaps outwardly and downwardly towards the said over-centre positions thereof, and third means for moving the said wing flaps downwardly and inwardly, past their said over-centre positions, to their closed positions.

In one form of the invention the said first means comprises a U-shaped plunger arranged to be engaged over the carton from the open end thereof and formed with convergent inner edges to engage the aforementioned crease lines in such walls and press them inwardly to break the crease. Preferably, as already mentioned, the said central crease line in each of the side walls of the carton splits in the downward direction into two crease lines which extend obliquely one to each of the respective bottom corners of the side wall, and the said first means is preferably arranged to press inwardly on the junctions of the said vertical and oblique crease lines. In a preferred form of the invention the apparatus includes means for substantially fully re-opening the carton, to receive its intended contents, after the said second side walls have been made concave as aforesaid. Such opening means may comprise a generally tapered plunger blade arranged to be inserted into the open end of the carton and then withdrawn. In one embodiment of the invention, the plunger is such that the second side walls keep a sufficient set that they will readily resume their concave configuration when the wing flaps are subsequently pressed in to their closed positions. However in an alternative embodiment, the side walls are returned to a generally planar condition, the breaking of the creases of the side walls allowing these walls subsequently to readily adopt the concave configuration. The said second means preferably comprises a suitably shaped blade. In one embodiment the said blade is arranged to operate in conjunction with a pivoting blade which acts on one of the top closure flaps to assist its inward and downward folding at the same time as the wing flaps are moved outwardly and downwardly. In an alternative embodiment, this action may be achieved moving the carton upwardly against a stationary- blade. Preferably a suitably shaped stationary guide is arranged to continue the closing movement of the said top closure flap as the carton moves further along the said path through the apparatus.

The said third means may comprise a mechanism arranged for rectilinear up and down movement in a direction to engage over t e top of the carton to press the said flaps downwardly and then to press them inwardly, either by rectilinear movement or by pivotal inward movement of the arms of a tongs mechanism. Alternatively a mechanism may be provided for moving the said wing flaps downwardly and inwardly and then squeezing the carton body at right angles to that movement of the wing flaps, i.e. parallel to the general planes of the side walls with which the wing flaps are then engaged, to render those walls, and the wing flaps, outwardly concave and thus to hold the carton closed in the manner previously described.

Embodiments of the invention will now be described by a; of example and with reference to the accompanying drawings, in which:-

Figures 1 to 3 are perspective views of a container of the kind described, in the form of a carton, Figure 1 showing the carton with its top fully open, Figure 2 with it partly closed, and Figure 3 with it fully closed; and

Figures 4 to 8 are perspective views of different stations in an apparatus, illustrating successive stages in the closure of the top of a carton of the kind shown in Figures 1 to 3 and in particular:

Figure 4 shows a first station for closing the bottom of the carton;

Figure 5A shows a second station at which the creases of the carton side walls are broken; Figure 5B shows an alternative mechanism for breaking the creases of the carton side walls at the second station,-

Figure 6A shows a third station at which the carton is fully reopened to receive its contents,- Figure 6B shows an alternative construction for a plunger blade of the third station;

Figure 7A shows a fourth station at which the top closure flaps are folded inwardly and downwardly;

Figure 7B shows an alternative construction for the fourth station;

Figure 8A shows the fifth and final station at which the wing flaps are folded down;

Figure 8B shows an alternative construction for the final station; and . Figure 8C shows another alternative construction for the final station.

The carton whose closing is illustrated by way of example in Figures 4 to 8 differs only from that of Figures 1 to 3 in that it is longer, in terms of its height.

Referring to Figure 4, a carton 20 with its top fully open, i.e. as shown in Figure 1, is placed in one of a series of holders 21 spaced through the apparatus. The holders 21 are in practice secured to respective carrier plates 22 movable through the apparatus on fixed guides 23 by means of a driving chain 24, but the holder is shown spaced away from its carrier plate in Figure 4, for clarity of illustration.

Each holder 21 comprises upper and lower U-shaped frame members 25,26 arranged to embrace a carton 20. The carton is placed in a holder 21 at a first station shown in Figure 4, with its bottom 27 still open, and closing of the container bottom flaps is carried out by conventional mechanism which forms no part of the present invention. As the carton moves to a second station, shown in Figures 5A and 5B, it becomes supported by an underneath control bar 28 and a rear control bar 29, which continue to support and control the carton as it progresses through the apparatus.

Referring now in particular to the operations at the Figure 5A station, at this station the opposite side walls 2 of the carton, i.e. the walls which carry the wing flaps 6, are urged inwardly so as to break the crease lines 8,9 sufficiently to set the walls in a concave configuration suitable to receive the wing flaps in due course. This is achieved by means of a substantially inverted U-shaped plunger blade 30, with convergent inner edges 31, which descends through inwardly facing slots 32 in the upper frame members 25, in line with the central creases 8 in the carton, so as to press the walls 2 inwardly. In this embodiment the drive mechanism is arranged to hold the cartons stationary at this and subsequent stations whilst the various operations are being carried out. Embodiments of the invention may however be envisaged in which the movement of the cartons is continuous. Figure 5B shows an alternative device for breaking the crease lines 8,9. Two similar mechanisms are mounted below the control bar 28, each comprising a pneumatic cylinder 200 having its piston rod 201 pivotally connected to a crease breaking arm 202 itself pivotally mounted in a respective elongate slot 203 in the bar 28. Actuation of the cylinders at the appropriate time causes the arms 202 to swing up from their out of the way positions shown in full lines, in which they are stowed below the surface of the bar 28, to engage the side walls 2 of the carton in the regions of the junctions between the crease lines 8 and 9, so as to break the crease lines. The mechanism of Figure 5B is preferred to that of Figure 5A in that it is more effective in breaking the crease lines 9 as well as the crease lines 8, which is important for proper closing of the tops of the cartons in due course. After the side walls 2 have been given a concave set as just described, the carton is moved to a third station depicted in Figure 6A. At this station a plunger blade 33, whose side edges 34 converge downwardly from a maximum width equal to the spacing between the- side walls 2 of the carton, is moved downwardly into the carton so as to fully open it again (without destroying the concave set of the side walls 2) to make it ready to receive its intended contents. However as the side wall crease lines 8, 9 have already been broken, it is not necessary that the side walls 2 maintain their concave configuration at this stage.

Figure 6B shows an alternative construction for the plunger blade, here designated 133. In this embodiment, the side edges 134 of the blade diverge to an extent substantially greater than the width of the carton body, so as to impart an outward set to the crease lines 10 in the wing flaps 6, preparatory to closure. This plunger blade 133 is operated in the same way as that shown in Figure 6A. The carton is now moved to a fourth station shown in Figure 7A. At this station a creasing blade 35, arranged in the same vertical plane as the creases 8 in the carton side walls 2 and wing flaps 6, descends into the open top of the carton so as to engage the inside faces of the wing flaps, along the crease lines 8, and push the flaps outwardly and downwardly. At the same time a pivoting blade 36 swings inwardly to fold the top closure flap 3 inwardly and downwardly. A stationary plough strip 37 has its upstream end 38 at this point and is effective, as the top closure flap 3 is folded inwardly and downwardly as just mentioned, to hold the tear strip 5 up, substantially vertically, by folding it about its inner line of perforations 39. The plough strip 37 then maintains the tear strip in a vertical position as the carton moves to the next station. A further stationary plough strip 40 has its upstream end 41 immediately adjacent the downstream end of the pivoting blade 36 which acts on the top closure flap 3, and as the carton begins to leave the Figure 7A station the plough strip 40 urges the top closure flap further down until, when the carton arrives at the final top closing station, depicted in Figures 8A to 8C, the top closure flap 3 (but not the tear strip 5) and the wing flaps 6 are horizontal.

Between the station of Figure 7A and the next station the underneath control bar 28 rises at 42 (see Figure 8A) so as to lift the carton sufficiently, relative to the holder 21, for the wing flaps to clear the side arms of the upper frame member 25 when such flaps are subsequently folded down.

Figure 7B shows an alternative construction for the fourth station. It should be noted that the operations shown in the region outlined in chain-dot lines actually occur at the same position but have been shown separately for clarity. In this embodiment, the reciprocating creasing blade 35 operates in the same manner as the first embodiment. However in this arrangement the carton is supported by a pneumatically operated platform 128. As the creasing blade 35 is moved upwardly after contact with the carton, the carton is also moved upwardly by the platform 128 to a position where the top closure flaps 3 and 4 contact respective stationary members 136 which fold the top closure flaps inwardly and downwardly. Then, as the carton is moved to the next station, a pair of fixed plough bars 140 bring the top closure flaps (excluding the tear strip 5) and the wing flaps down to the horizontal. The upward movement of the carton by the platform 128 replaces the upward movement provided by the raising of the underneath control bar 28 shown in Figure 8A.

At the fifth and final station shown in Figure 8A a tongs device 43 is mounted for up and down movement. With the carton stopped at this station the tongs device is lowered so that its arms 44 push the wing panels 6 downwardly. The tongs mechanism is then operated so that pads 45 on the ends of its arms push the wing flaps inwardly, sufficiently as also to return the side walls 2 to their concave configurations as previously described, whereby the wing flaps are held in their closed conditions. It will be noted that the plough 37 which holds the tear strip 3 vertical is relieved at 48 to permit the up and down movement of the tongs device. An optional feature at the Figure 8A station is a pair of adhesive applicators 46 provided with lateral nozzles 47, which are operative to apply spots of glue to the side walls 2 before the wing flaps are folded down, to positively hold such flaps in their closed conditions. An alternative embodiment for the final station is shown in Figure 8B. A wing flap folder 143 is arranged so as to be movable up and down. As the folder 143 is lowered to the carton, arms 144 are positioned such that the wing flaps 6 are folded downwardly. The arms 144 are then moved toward each other to thereby press the wing flaps 6 into the respective carton side walls 2, thereby returning these walls to their concave configura ion. The wing fl_.p folder 143 is then opened up and moved up to its initial position.

Another alternative embodiment for the final station is shown in Figure 8C. The fixed plough bars 140 shown in Figure 7B appear again, and it will be seen that they have by now urged the top closure flaps 3 and 4 and the wing flaps 6 down into substantially the same horizontal plane, level with the tops of the carton side walls. The mechanism at this station comprises a pair of folding lugs 150 movable vertically downwardly to engage the wing flaps and fold them downwardly and inwardly into engagement with the carton side walls 2. Once the wing flaps have reached this position, a pair of squeeze pads 151 move inwardly, horizontally, to engage the other pair of side walls 1 of the carton, level with the folded down wing flaps 6, and squeeze the carton slightly in the direction parallel to the general planes of the side walls 2 so as impart the desired concave set to those lar-ter walls, and the wing flaps, whereby to cause the wing flaps to remain in their carton closing positions.

Conventional mechanism may be provided downstream of the Figure 8 station for gluing and closing the tear strip 5 before the carton is removed from the apparatus. Whilst the apparatus has been described in relation to the stepwise operation thereof, it will be appreciated that the apparatus can be modified to operate continuously for high volume throughput. In such embodiments the movement could for example be cam controlled and each operation could be carried out by a number of overhead assemblies moving in synchronization with the cartons. It will also be appreciated that a variety of carton styles having the basic features of the carton initially described, but with variations such as modified tear strips, or glue flaps on the uppermost surface or front face, can be processed by this apparatus.

Claims

1. Apparatus for closing the tops of cartons of the kind described, comprising conveyor means (21-24) for conveying such cartons along a path of movement, first means (30; 202) for acting on said second pair of side walls (2) of each carton to make them outwardly concave, second means (35) for moving the said wing flaps (6) outwardly and downwardly towards the said over-centre positions thereof, and third means (43; 143; 150) for moving the said wing flaps downwardly and inwardly, past their said over-centre positions, to their closed positions.

2. Apparatus as claimed in claim 1, wherein the said second pair of side walls (2) of the carton are each formed with a vertical central crease line (8) to enable the wall to be made outwardly concave, the said first means (30; 202) being arranged to press inwardly on the said crease lines.

3. Apparatus as claimed in claim 2, wherein the said first means comprises a vertically movable inverted U- shaped plunger blade (30) with upwardly convergent inner edges (31) for engaging the said side walls.

4. Apparatus as claimed in claim 2, wherein, in each of said side walls of the carton, the said central crease line (8) splits in the downward direction into two crease lines (9) which extend obliquely one to each of the respective bottom corners of the side wall, and the said first means (202) is arranged to press inwardly on the junctions of the said vertical and oblique crease lines (8,9) .

5. Apparatus as claimed in claim 4, wherein the said first means comprises a pair of arms (202) pivotally mounted beneath the path of travel of the carton and operable to pivot upwardly and inwardly to press on the said crease lines (8,9) at their junctions.

6. Apparatus as claimed in any preceding claim, wherein the said second means includes a vertically extending blade (35) arranged to enter the open top of the carton whilst engaging the inside faces of the said flaps.

7. Apparatus as claimed in claim 6, wherein the said vertically extending blade (35) is arranged to descend into the open top of the vertically stationary carton.

8. Apparatus as claimed in claim 7, further including a pivoting blade (36) arranged to pivot inwardly to fold down one of the top closure flaps (3) simultaneously with the operation of the said vertically movable blade (35) .

9. Apparatus as claimed in claim 6, wherein the said vertically extending blade (35) is stationary and including means (128) for moving the carton upwardly to engage the said blade.

10. Apparatus as claimed in any preceding claim, wherein one of the top closure flaps (3) of the carton incorporates a tear strip at its distal end, the apparatus including means (37) for temporarily preventing the tear strip from being folded down with the top closure flap.

11. Apparatus as claimed in claim 10, wherein the said means comprises a plough strip (37) extending along the said path of movement of the cartons.

12. Apparatus as claimed in any of claims 6 to 11, including means (40; 140) for holding the said wing flaps (6) and top closure flap (3) down in substantially horizontal positions as the carton progresses further along said path of movement following the operation of said second means.

13. Apparatus as claimed in any preceding claim, wherein the said third means comprises a tongs device (43) which is movable bodily downwardly to move the said wing flaps downwardly and then, by inward movement of its pivoting arms (44) , to move the said flaps inwardly.

1 . Apparatus as claimed in any of claims 1 to 12, wherein the said third means includes means (151) for squeezing the said side walls (2) in a direction parallel to their general planes, after the said wing flaps (6) have been moved downwardly and inwardly, so as to urge the said side walls and the wing flaps into outwardly concave configurations.

15. Apparatus as claimed in any preceding claim, including means (33; 133) for opening each carton for filling, after the operation of said first means (30; 202) .