The invention relates to a device and a method of folding a chain of bags. Such a chain of bags, for example sachets, can be used in the food industry for the packing of foodstuffs. The chain can comprise, for example, 5 to 25 sachets. The sachets can be rectangular in shape and are respectively connected to one another by a top or bottom side by means of a weakening line in the package. During use, the known filling machine fills the successive sachets of the chain with a measured quantity of foodstuffs, after which a worker folds the chain into a stack, wherein the bags are folded about the weakening line and the stack ends up standing on the respective top and bottom side of the sachets and can be packed, for example, in a case. Such a folding operation is time-consuming and can limit the speed of the filling machine. Moreover, the manual folding of the successive chains into stacks is not uniform, so that the packing of the stacks into cases can present problems.

An object of the invention is to provide a device and method of folding chains of bags which produces uniform stacks.

This object is achieved through a first aspect of the invention by a device for folding a chain of a multiplicity of bags, comprising: a first conveyor belt for the conveyance of the chain from a first end to a second end of the conveyor belt, pressure rollers, fitted close to the second end above the first conveyor belt, for the guidance of the chain, a forming board, disposed at the second end of the first conveyor belt, for the reception of the guided chain, and a trapdoor, fitted in the forming board, for the passage of the stack.

The insight of the invention is that, since the pressure rollers guide the chain to the forming board at a constant speed, the chain is uniformly folded in the forming board. After the folding of the chain, the trapdoor can be opened, whereby the stack falls through the forming board to a following conveyor belt or directly into a case.

In one embodiment, the device is provided with a first movable pressure element, which is placed above the forming board opposite the second end of the first conveyor belt and is arranged to press against a first bag of the chain, and a first drive, coupled to the first movable pressure element, which first drive is arranged to move the first movable pressure element over the forming board in a first direction conforming to the motional direction of the chain on the first conveyor belt. The first movable pressure element is placed above the forming board, wherein the first movable pressure element can receive the first bag of the chain and applies a first force to the first bag, a second bag of the chain, following the first bag, applies to the first bag a second force opposite to the first force and, by virtue of the weakening line, the first and the second bags tip over and the successive bags are folded into the stack, in which the successive bags stand alternately on the top and the bottom side.

In a further embodiment, the first movable pressure element comprises a first plate standing vertically with respect to the forming board.

In a further embodiment, the first drive is arranged to adjust a speed of the first movable pressure element, which speed is less than a speed of the chain on the first conveyor belt for folding the stack. Since the speed of the first movable pressure element is less than the speed of the received chain on the forming board, the chain is folded into a stack.

In a further embodiment, the device comprises a second pressure element, which second pressure element is placed between the first pressure element and the second end of the first conveyor belt, and a second drive arranged to move the second pressure element over the forming board towards the first element for pressing against a first part of the last bag of the stack. After the chain has been folded into the stack, the second pressure element can be placed against the last bag in the stack, whereby the shape of the stack is maintained and can fall through the trapdoor to be opened.

In a further embodiment, the second pressure element comprises a second plate standing vertically with respect to the forming board.

In a further embodiment, the device comprises a third movable pressure element, which third movable pressure element is placed between the first movable pressure element and the second end of the first conveyor belt, and

a third drive, arranged to move the third movable pressure element over the forming board towards the first movable pressure element for pressing against a second part of the last bag of the stack. The application of pressure to a first part and a second part of the last bag of the pack, for example the top side and the bottom side of the upright last bag, enables the stack to maintain its shape.

In a further embodiment, the third movable pressure element comprises a rotatable arm, which is rotatable about a shaft parallel with a plane of the first conveyor belt and stands transversely to the motional direction of the chain on the conveyor belt. The rotatable arm makes it possible to fit the second movable pressure element and the third movable pressure element in a simple and compact manner close to the second end of the first conveyor belt.

In a further embodiment of the device, the device comprises a sensor for respectively detecting the start and the end of the chain on the first conveyor belt. Detecting the start and the end of the chain enables the movements of the respective first, the second and possibly the third movable pressure body to be synchronized with the chain to be folded.

In one embodiment, the device comprises an actuating device for opening and closing the trapdoor for the passage of the stack.

In a further embodiment, the device comprises a funnel, which is fitted below the forming board for guiding a stack which has fallen through the forming board to a second conveyor belt, which is adapted to be coupled to the device. The funnel guides the falling stack to the second conveyor belt, whereupon the stack virtually retains its folded shape. The funnel can consist of two side plates, which on either side of the hole to be opened are disposed transversely to the direction of the first conveyor belt.

In a further embodiment of the device, the device comprises a control unit, which is coupled to the first and second drives, the actuating device of the trapdoor and the sensor, wherein the control unit is arranged to successively execute: a) detecting the start of the chain, b) moving the first pressure element from a first starting position over a first predetermined distance in the first direction for folding the chain, c) detecting the end of the chain, d) moving the second pressure element from a second starting position over a second predetermined distance in the first direction, wherein in an end position of the first and second pressure elements the distance between the first pressure element and the second pressure element conforms to a thickness of the stack to be folded, e) opening the trapdoor, and moving apart the first and the second movable pressure elements to allow the stack to fall through the forming board. The control device synchronizes all movements of the first and the second pressure elements for the folding of the stack, opening the trapdoor and release of the stack, the closing of the trapdoor, and the transport of the first and the second movable pressure bodies into the respective first and second starting positions.

The above object is achieved through a second aspect of the invention by a method of folding a chain of bags, comprising: receiving and guiding the chain over a first conveyor belt to a forming board, pressing a start of a stack on the forming board for folding the stack comprising the guided chain, pressing an end of the stack on the forming board, and opening the forming board for the passage of the stack.

A further embodiment of the method further comprises detecting a start of the chain, moving a first pressure element from a first starting position over a first predetermined distance in the first direction for folding the chain, detecting an end of the chain, moving a second pressure element from a s econd starting position over a secon d predetermined distance in the first direction for pressing against the end of the stack, wherein in an end position of the first and second pressure elements the distance between the first pressure element and the second pressure element conforms to a thickness of the stack to be folded, and moving apart the first and the second movable pressure elements to allow the stack to fall through the forming board.

Where the terms "above", "below", "inside" and "outside" are used in this document, it should be understood that these refer to the orientation during use, i.e. the orientation of the device when this is mounted in a factory building.

Embodiments according to the invention will be explained below, by way of example, with reference to a number of figures, wherein:

Fig. 1 shows a schematic side view of a sachet-folding device according to one embodiment;

Fig. 2 shows a schematic top view of a chain of sachets;

Fig. 3 shows a schematic side view of a folded stack of sachets;

Fig. 4 shows a schematic front view of the device of Fig. 1 ;

Fig. 5 shows a schematic top view of the device of Fig. 1 ; and

Fig. 6 shows a detail of the folding board, with movable plates, of the device of Fig.1.

In the figures, identical reference numerals conform to identical components.

The working of the device is explained with reference to Fig. 1 , Fig. 4, Fig. 5 and Fig. 6. Fig. 1 shows the device 1, which comprises a frame 2, a first conveyor belt 3 for conveying the chain from a first end 4 to a second end 5 of the conveyor belt 3. The conveyor belt 3 is coupled to the frame 2. The conveyor belt 3 can be disposed, for example, horizontally. The first end 4 of the first conveyor belt is disposed by an outlet of, for example, a filling machine. The chain comprises a fixed number of bags, for example 5, 10 or 25 bags or sachets, wherein the bags have, for example, a square or rectangular shape.

Fig. 2 shows in schematic representation a top view of a chain 6 of six sachets 60. The bags can be made of paper, card or plastic, for example polypropylene. The bags can be provided with a weakening line or a perforation in the material of the bags on a respective top and bottom side of the bag, in which case the bags are connected to one another by the weakening line or perforation so as to form the chain.

Fig. 3 shows a chain 7 of six sachets, which chain has been folded into a stack. After the filling of the bags, the chain 6 is received at the first end 4 of the first conveyor belt 3. The first conveyor belt 3 is arranged to convey the chain 6 from the first end 4 to the second end 5. The first conveyor belt can possibly convey several chains at once, in which case the chains have an equal length and lie parallel to one another on the first conveyor belt with an interspace between the respective mutually adjacent chains 6 and are simultaneously supplied, so that a respective start and end of the chains on the first conveyor belt are equally situated with respect to one another. The number of chains that can be processed in parallel on the first conveyor belt is, for example, two, though five or ten chains are also possible. The device 1 further comprises pressure rollers 8, which are fitted close to the second end 5 of and above the first conveyor belt 3 in the frame 2 and are arranged to guide the chain 6, wherein the pressure rollers 8 press the bags against the first conveyor belt 3. The pressure rollers 8 can be driven by a separate drive, the peripheral speed of the pressure rollers 8 on the edge of the bags conforming to the speed of the first conveyor belt 3. The device can be provided with a plurality of pressure rollers for processing a plurality of parallel chains, wherein at least one pressure roller per chain is used for the parallel guidance of the chains. In one embodiment, the pressure rollers 8 press the sides of the bags of the chain 60 against the conveyor belt 3.

At the second end 5 of the first conveyor belt 3, a forming board 9 is fitted in the frame 2 so as to receive the supplied guided chain 6 and form a stack by folding of the guided chain. The forming board 9 can be horizontally disposed and is further provided with a trapdoor 10 for the passage of the stack. The trapdoor 10 can comprise two trapdoor parts 11, 12, which can open via hinges on both sides to form a hole through which the pack can fall. The device further comprises an actuating device 30, 31 for opening and closing the trapdoor parts 11, 12. The device 1 is further provided with a first movable pressure element, which comprises a first, with respect to the plane of the forming board 9, vertical or upright movable plate 13. Fig. 1 shows the first movable plate 13, which is fitted above the forming board 9 opposite the second end 5 of the first conveyor belt 3 for pressing against a first bag of the chain 6 emanating from the first conveyor belt 3. The device further comprises a first drive 14, which is coupled to the first movable plate 13. The first drive 14 is arranged to move the first movable plate 13 from a first starting position 15 to a first end position 16 over the forming board 9 in a first direction conforming to the motional direction 17 of the chain on the first conveyor belt. The first starting position 15 is, for example, by a join between the first and second trapdoor parts 11, 12. The first starting position 15 can also be situated at a position between respectively a hinge of the first trapdoor part 11 and the hinge of the second trapdoor part 12 with the forming board, which position is dependent on the pliability of the chain. The end position 16 is by the hinge of the second trapdoor part 12 with the forming board 9. The device 1 can further comprise a second movable pressure element, which comprises a second, with respect to the forming board, vertical or upright plate 18. Fig. 1 shows the second movable plate 18, which is placed between the first movable plate 13 and the second end 5 of the first conveyor belt 3. A second starting position 40 of the second movable plate 18 is here chosen such that the chain can be freely conveyed from the conveyor belt 3 to the forming board 9, for example below the second end 5 of the first conveyor belt 3. The device further comprises a second drive 20, which is coupled to the second movable plate 18 and which second drive is arranged to move the second movable plate 18 from the second starting position 40 to a second end position in a, with respect to the forming board 9, vertical plane 42, for pressing against a first part of the last bag of the stack, for example the bottommost part of the last bag, whereby the shape of the stack is maintained and the stack can fall through the trapdoor to be opened.

In one embodiment, the device comprises a third movable pressure element, which comprises, for example, a rotatable arm 19. Fig. 1 shows the rotatable arm 19, which is rotatable about a shaft 21 parallel with a plane of the first conveyor belt 3 and stands transversely to the motional direction 17 of the chain on the conveyor belt, between the first movable plate 9 and the second end 5 of the first conveyor belt, for example above the starting position of the second movable plate 18. The device 1 further comprises a third drive 22, which is coupled to the rotatable shaft 21 and is arranged to rotate the rotatable arm 19 from a third starting position 41 to a third end position in the vertical plane 42 for pressing against a second part of the last bag of the stack 7, for example the bottommost part of the last bag, whereby the shape of the stack is better maintained and the stack can fall through the trapdoor to be opened. The third starting position 41 of the rotatable arm 19 is here chosen such that the chain can move freely from the first conveyor belt to the forming board 9, for example above the second end 5 of the first conveyor belt, wherein the chain can move between the second movable plate 18 and the rotatable arm 19 to the forming board 9.

The device can additionally comprise a funnel 24, which is fitted below the trapdoor 11, 12 in the forming board 9 and is provided with two guides or plates 25, 26 for guiding a stack 7 which has fallen through the forming board to a second conveyor belt 45 which is adapted to be coupled to the device 1, whereupon the stack 7 retains the folded shape.

Fig. 4 shows a front view of the device 1 with the couplable second conveyor belt

45. The device can further be provided with a sensor 23, for example an optical sensor, which is arranged to respectively generate a signal indicating the start and the end of the moving chain 6 on the first conveyor belt 3. If a plurality of parallel chains are conveyed by the conveyor belt 3, the sensor 23 can contain a plurality of optical sensors, which are positioned such that the respective start and end of the chains can be detected.

Fig. 5 shows a top view of an embodiment of the device of Fig. 1 , in which 5 parallel chains 60, 61, 62, 63, 64 can be folded. Fig. 5 further shows the drive rollers 8 for driving the respective chains, and an optical sensor 23.

Fig. 6 shows a detail of the forming board 9 with the first starting position

15 and the first end position 16 of the first movable plate 13, the second starting position 40 of the second movable plate 18, the third starting position 41 of the rotatable arm 19, and the vertical plane 42 in which the end position of the second movable plate 19 and the end position of the rotatable arm 19 are found.

The device 1 is further provided with a control unit 27, for example a Programmable Logic Controller (PLC) known to a person skilled in the art. The PLC is electrically connected to the first drive 14, the second drive 20, the third drive 22, the actuating device 30, 31 of the trapdoor 11, 12 and the optical sensor 23. The PLC 27 can further be arranged for successively: a) detecting the start of the chain 6 from the signal of the optical sensor 23, b) moving the first movable plate 13 over the forming board 9 from a first starting position 15 to a second end position 16 over a first predetermined distance in the first direction for folding the chain 60, wherein the speed of the first movable plate 13 is constant and is less than a speed of the chain on the first conveyor belt for folding the stack, c) detecting an end of the chain from a signal of the optical sensor 23, d) moving the second movable plate 18 from a second starting position 40 over a second predetermined distance to the second end position in the vertical plane 42, e) moving the rotatable arm 19 from the third starting position 41 to the third end position in the vertical plane 42, wherein, in the first end position 16 of the first movable plate 13, in the second end position of the second movable plate 18 and in the third end position of the rotatable arm 19, the respective distances LI, L2 between the first movable plate 13 and the second movable plate 18, and the first movable plate 13 and the end of the rotatable arm 19, conform to a thickness of the stack to be folded, f) opening the trapdoor 10 and moving apart the first, movable plate 13, the second movable plate 18 and the rotatable arm 19 to allow the stack to fall through the forming board 9, and g) the returning of the respective first movable plate 13, the second movable plate 18 and the rotatable arm 19 to respectively the first starting position 15, the second starting position 40 and the third starting position 41. The movements of the second movable plate 18 and the rotatable arm 19 from the, respectively, second starting position 40 and third starting position 41 can run synchronously, though it can also be that the said movement of the rotatable arm 19 precedes moving the second upright plate 18.

During working, the device executes steps a) to g) under the control of the PLC 27 and repeats these steps for successive chains conveyed by the first conveyor belt 3 to the forming board 9. A second conveyor belt 45, which can be fitted below the funnel 24 and the trapdoor 10, can be provided to convey the packs to a following destination, for example a wrapping device (flow wrapping apparatus) or a packing device (case packing apparatus) for respectively wrapping the packs in film or packing the folded packs in cases.

It should be clear to the person skilled in the art that the invention is not limited to that which is described here, and that several equivalent embodiments of the invention are possible.