WO2014110597A1

WO2014110597A1 - Apparatus for packaging articles and method of packaging articles

Info

Publication number: WO2014110597A1
Application number: PCT/US2014/011542
Authority: WO
Inventors: Fabrice Avril; Aurelien MAURATILLE
Original assignee: Meadwestvaco Packaging Systems, Llc
Priority date: 2013-01-14
Filing date: 2014-01-14
Publication date: 2014-07-17
Also published as: GB201300605D0

Abstract

An apparatus (10) for packaging one or more articles in a carton (C), the carton (C) comprising a plurality of panels (Bl, B2), the apparatus (10) comprising at least one conveyor (12) for conveying cartons (C) to a locking station (L), the locking station (L) comprising at least one fixed guide member (16, 24) for guiding a pair of panels (Bl, B2) of each carton (C) into an overlapping relationship and a moveable guide member (26) for maintaining a first one of the pair of panels (B2) in a folded position, a second one of the pair of panels (Bl) is folded into overlapping relationship therewith, the moveable guide member (26) being moveable with respect to the fixed guide member (24), so as to disengage the moveable member (26) from engagement with the carton (C).

Description

APPARATUS FOR PACKAGING ARTICLES AND METHOD OF PACKAGING ARTICLES

FIELD OF THE INVENTION

The present invention relates to an apparatus for packaging articles and a method of packaging articles; more specifically, but not exclusively, to an apparatus for forming part of a packing machine for assembly of wrap-around style cartons and method of performing the same.

BACKGROUND OF THE INVENTION

In the field of packaging, it is often required to provide consumers with a package comprising multiple primary product containers. Such multi-packs are desirable for shipping and distribution and for display of promotional information. For cost and environmental considerations, such cartons or carriers need to be formed from as little material as possible and cause as little wastage in the materials from which they are formed as possible. Another consideration is the strength of the packaging and its suitability for holding and transporting large weights of articles.

It is desirable to automate assembly and construction of the cartons or carriers. In particular, in wraparound-style cartons, it is desirable to automate securing a pair of panels, such as a pair of base panels, in overlapping relationship. It is desirable to quickly and easily perform maintenance on the packaging system in the event of a stoppage of the packaging system for example as a result of an error such as a handling error, jam or misfeed; in this way downtime or periods of inoperability can be minimised.

SUMMARY OF INVENTION

The present invention seeks to overcome or at least mitigate the problems of the prior art.

According to a first aspect of the present invention there is provided an apparatus for packaging one or more articles in a carton comprising a plurality of panels; the apparatus comprises at least one conveyor for conveying cartons to a locking station; the locking station comprises at least one fixed guide member for guiding a pair of panels of each carton into an overlapping relationship, and a moveable guide member for maintaining a first one of the pair of panels in a folded position, a second one of the pair of panels is folded into overlapping relationship therewith, the moveable guide member being moveable with respect to the fixed guide member, so as to disengage the moveable guide member from engagement with the carton. Advantageously, the apparatus provides that a partially assembled or locked carton can be removed from the locking station without needing to tear or cut the carton free from the apparatus, thereby reducing the likelihood of damage to the apparatus, reducing the downtime of the machine and reducing the likelihood of injury to an operator.

Preferably, the moveable guide member is moved from a first, operative, position to a second, release, position to facilitate removal of a carton from the locking station in the event of a stoppage in a system of which the apparatus is a part.

Preferably, the moveable guide member is disposed in a first, operative, position to form a continuous guide with the at least one fixed guide member for locking the pair of panels together and wherein the moveable guide member is disposed in a second, release, position to form a gateway between the at least one fixed guide and the moveable guide for facilitating removal of a carton from the locking station through the gateway in the event of a stoppage in a system of which the apparatus is a part.

Preferably, the at least one fixed guide comprises a first guide member disposed at an upstream location, and a second guide member disposed at a downstream location, such that when the moveable guide is disposed in a first, operative, position the first guide member is disposed at an upstream end of the moveable guide member and the second guide member is disposed at a downstream end of the moveable guide member.

Preferably, the moveable guide comprises a downstream terminus arranged such that cartons may be disengaged from the moveable guide by slidably moving the cartons downstream.

Preferably, the moveable guide is moved in an upstream direction to a release position in order to remove a carton from the locking station.

In some embodiments, the first guide member comprises a recess for receiving the moveable guide member when disposed in a second, stowed or release, position.

Preferably, the first guide member comprises an elongated slot for receiving a follower coupled to the moveable guide member, thereby controlling movement of the moveable guide member. Preferably, the at least one fixed guide comprises a folding guide member which is arranged to have an engaging edge which is divergently arranged with respect to the movable guide.

In some embodiments, the folding guide extends under or over the moveable guide so as to wrap the carton about the moveable guide.

Preferably, the folding guide folds the second panel such that the moveable guide is disposed between the first and second panels.

Preferably, the second panel is wrapped at least partially about the moveable guide.

Preferably, the second panel is folded into overlapping relationship with the first panel whilst being conveyed through the locking station.

Preferably, the moveable guide member is tapered at a downstream end.

Alternatively, the moveable guide member comprises a lower edge which is chamfered at the downstream end.

In some embodiments, the second guide member comprises an inclined ramp shaped complementary to the moveable guide member such that when in the first, operative position the moveable guide mates with the second guide member, such that an upper edge of the moveable guide and an upper edge of the second guide member are flush with one another.

The second guide member may comprise an inclined ramp shaped to bring the second panel into face contacting relationship with the first panel as the carton is conveyed downstream.

Preferably, the moveable guide is coupled to an actuator such as a piston and cylinder arrangement.

In some embodiments, the apparatus comprises a pair of conveyors disposed on opposing sides of the carton for conveying the carton to the locking station. Preferably, each of the pair of conveyors comprises a lug assembly for engaging with the carton.

Preferably, each of the pair of conveyors are moveable in a direction transverse to the direction of article travel, such that the gap between the conveyors can be widened to release the carton from the conveyors.

According to a second aspect of the present invention there is provided a method of packaging articles comprising:

conveying a carton to a locking station upon a conveyor forming part of a packaging system; folding a first panel of the carton about one or more articles being packaged into a folded position;

maintaining the first panel in the folded position with a guide member;

folding a second panel about the guide member such that a moveable element of the guide member is disposed between the first and second panels of the carton;

detecting a stoppage of the packaging system; and

moving the moveable element so as to withdraw the moveable element from between the first and second panels of the carton;

removing the carton from the locking station.

The method may comprise:

restarting operation of the packaging system, and

conveying a subsequent article to the locking station. In some embodiments, moving the moveable element comprises:

actuating an actuator to slide the moveable element so as to withdraw the moveable element from between the first and second panels of the carton.

According to a third aspect of the present invention there is provided a packaging machine comprising the apparatus as described in the foregoing paragraphs, or for carrying out the method described in the paragraphs above.

Within the scope of this application it is intended that the various aspects, embodiments, examples, features and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings may be taken independently or in any combination thereof. For example, features described in connection with one embodiment are applicable to all embodiments unless there is incompatibility of features. BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a perspective view from above of an apparatus, in an operative position, forming part of a packaging machine according to a first embodiment of the invention;

Figure 2 is a perspective view from above of the apparatus of Figure 1 showing a carton being assembled;

Figure 3 is a perspective view from above of the apparatus of Figure 2 at a later stage of assembly;

Figure 4 is a perspective view from below of a portion of the apparatus of Figure 3;

Figure 5 is a perspective view from above of the apparatus of Figure 4 in a release position; and

Figure 6 is a perspective view from above of the apparatus of Figure 5 showing removal of a carton from the apparatus. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION

Detailed descriptions of specific embodiments of the apparatus and method are disclosed herein. It will be understood that the disclosed embodiments are merely examples of the way in which certain aspects of the invention can be implemented, and do not represent an exhaustive list of all of the ways the invention may be embodied. As used herein, the word "exemplary" is used expansively to refer to embodiments that serve as illustrations, specimens, models, or patterns. Indeed, it will be understood that the apparatus and method described herein may be embodied in various and alternative forms. The Figures are not necessarily to scale, and some features may be exaggerated or minimised to show details of particular components. Well- known components, materials or methods are not necessarily described in great detail in order to avoid obscuring the present disclosure. Any specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the invention. Referring to Figures 1 to 6, there is shown a perspective view of an apparatus 10 for a packaging machine capable of accepting an input of primary products such as, but not limited to, bottles or cans, hereinafter referred to as articles. In the embodiments detailed herein, the terms "carton" and "carrier" refer, for the non-limiting purpose of illustrating the various features of the invention, to a container for engaging, carrying, and/or dispensing articles, such as bottles. However, it is contemplated that the teachings of the invention can be applied to various containers, which may or may not be tapered and/or cylindrical. Other exemplary articles include bottles (for example metallic, glass or plastics bottles), cans (for example aluminium cans), tins, pouches, packets and the like.

The blank is formed from a sheet of suitable substrate. It is to be understood that, as used herein, the term "suitable substrate" includes all manner of foldable sheet material such as paperboard, corrugated board, cardboard, plastic, combinations thereof, and the like. It should be recognised that one or other numbers of blanks may be employed, for example, to provide the carrier structure described in more detail below.

In the exemplary embodiment, the blank is configured to form a carton C or carrier for packaging an exemplary arrangement of exemplary articles. For example, the arrangement is a matrix including rows and columns such as a 2x5 arrangement of articles. The blank can be alternatively configured to form a carrier for packaging other articles and/or different arrangements of articles.

The apparatus 10 comprises a pair of conveyors 12 disposed on opposing sides of an article path. The conveyors 12 each comprise lug assemblies 14a, 14b. The lug assemblies 14a, 14b are mounted upon a chain which is coupled to one or more sprockets (not shown). The sprockets are driven by an electric motor such as, but not limited to, a servo motor. The pair of conveyors 12 are disposed on opposing sides of a locking station L. The locking station L comprises a first fixed guide 16 at an upstream end and a second fixed guide 24 disposed at a downstream end. The locking station L comprises a moveable guide 26 disposed between the first and second fixed guides 16, 24. The moveable guide 26 is moveably mounted between the first and second fixed guides 16, 24. Preferably, the moveable guide 26 is slideably mounted between the first and second fixed guides 16, 24. A portion of a downstream end of the moveable guide 26 is shaped and arranged to be received by a portion of the second guide 24, when the moveable guide 26 is in a first

5 position, as shown in Figures 1 to 3. In the illustrated embodiment, the moveable guide 26 comprises a tapered end, a lower edge of the moveable guide 26 being chamfered, and the second fixed guide 24 comprises an inclined ramp. The inclined ramp is complementary in shape to the chamfered lower edge of the moveable guide 26, such that an upper edge of the moveable guide 26 is flush with an upper edge of the second fixed guide 24 and an upper edge

I 0 of the first fixed guide 16. A portion 24R of the fixed guide 24 extends alongside the second fixed guide 24, an upstream end of the portion 24R comprises an inclined ramp, the inclined ramp encourages a panel of the carton C, which has been wrapped under the moveable guide 26, upwardly to bring said panel into face contacting relationship with another panel of the carton C which is disposed above or over the moveable guide 26.

I 5

The movable guide 26 is mounted to a body 20 by an arm 28; the arm 28 extends through an elongate slot 18 provided in the first fixed guide 16. The arm 28 acts as a follower, defining the movement of the moveable guide 26. The moveable guide 26 is disposed on a first side of the first fixed guide 16 and the body 20 is disposed on a second side of the first fixed guide 16, the .0 second side opposing the first side. Preferably, the first fixed guide 16 comprises an elongate recess 17 or channel for receiving the moveable guide 26 therebetween. The elongate recess 17 restricts or controls movement of the moveable guide 26 in a direction transverse to a direction of article travel, which is indicated by direction arrow D3.

.5 A piston 30 is mounted to the body 20, as shown in Figure 5. The piston 30 is slideably mounted within a cylinder 22. Preferably, piston 30 is pneumatically operable to be extended from, and retracted into, the cylinder 22 so as to move the body 20, and hence the moveable guide 26, in a reciprocating linear fashion.

30 The locking station L comprises a panel folding guide 19; the panel folding guide 19 is disposed alongside the fixed guide 16 and moveable guide 26. The panel folding guide 19 extends below the moveable guide 26, when the moveable guide 26 is in the first position as shown in Figure 1 . The panel folding guide 19 is configured and arranged to fold one of the panels of the carton C into overlapping relationship with another of the panels of the carton C. In the illustrated embodiment, the locking station L is configured to fold a first base panel B2 into overlapping relationship with a second base panel B1 . In doing so, the panel folding guide 19 brings a first part T of a complementary locking mechanism coupled to the first base panel B2, such as an arrow-headed tab or other suitable tab, into engaging relationship with a second part A1 (see

5 Figure 1 ) of the complementary locking mechanism, provided in the second base panel B1 such as an aperture, slot or recess, thereby locking the first base panel B2 and the second base panel B1 together. In some embodiments the first part T of the complementary locking mechanism may include a secondary tab T2 (as shown in Figure 4) coupled between the first part T and the first base panel B2 and hingedly connected therebetween such as that disclosed

I 0 in EP0233078. In those embodiments including a secondary tab T2, the second base panel B1 is provided with a secondary aperture or slot A2 (see Figure 1 ) for receiving at least a portion of the secondary tab T2 so as to form a secondary point of engagement between the first and second base panels B2, B1 . It is envisaged that the first part T of the complementary locking mechanism coupled to the first base panel B2 and the secondary tab T2 will be folded

15 substantially around the movable guide 26 as illustrated in Figure 4 such that the first part T and the secondary tab T2 are substantially disposed on opposing sides of the moveable guide 26. It will be appreciated that the provision of the secondary tab T2 increases the security or strength of the complementary locking mechanism however in the event of a stoppage the combination of the first part T and the secondary tab T2 may inhibit removal of the carton C whilst disposed

-0 about the moveable guide 26 when disposed in its operative position, and therefore retraction of the moveable guide 26 into the release position thereby withdrawing the movable guide 26 from the carton C is particularly advantageous. It will be appreciated that during the assembly process the first base panel B2 and the second base panel B1 are at least partially locked together whilst the movable guide 26 is disposed, at least in part, between the first base panel

.5 B2 and the second base panel B1 . It is therefore advantageous to be able to withdraw the movable guide 26 in order to release a carton C in an at least partially locked condition.

In other embodiments it is envisaged that the carton C may comprise alternative locking arrangements.

30

As shown in Figures 1 and 2, the carton C, prior to entering the locking station L, is arranged such that the second base panel B1 is folded about the base of a group of articles B (not shown). The first base panel B2 extends downwardly, being arranged substantially perpendicularly to the second panel B1 . The carton C is transported to the locking station L by the conveyors 12. In doing so, the second base panel B1 is moved over the upper edge of the first fixed guide 16. The first base panel B2 is brought into engagement with the panel folding guide 19, such that it is disposed between the 5 panel folding guide 19 and the first fixed guide 16.

The lug assemblies 14a, 14b engage with apertures in the carton C. The lug assemblies 14a engage with apertures on a first side of the carton C, and the lug assemblies 14b engage with apertures on a second side of the carton C. In the illustrated embodiment, the apertures receive

I 0 a portion of a lower portion or heel of the articles (not shown). The pair of conveyors 12 move the carton C downstream in the direction indicated by direction arrow D3 as shown in Figures 2 and 3. The first base panel B2 is folded by the panel folding guide 19 into overlapping relationship with the second base panel B1 . In this way, the first base panel B2 is folded or wrapped below the moveable guide 26 as shown in Figures 3 and 4. It will be appreciated that

15 the moveable guide 26 prevents the first part T of the complementary locking mechanism from fully engaging with the second part A1 of the complementary locking mechanism.

It will be appreciated that due to the tapered shape of the movable guide 26, the portion of the first base panel B2 disposed at the downstream end of the carton C is brought into closer -0 proximity to the second base panel B1 than the portion of the first base panel B2 disposed at the upstream end of the carton C.

The first base panel B2 slides or rides up the inclined ramp of the second fixed guide 24. During normal operation of the packaging system the cartons C are transferred away from the locking

.5 station L by the pair of conveyors 12. The cartons C are moved downstream and the moveable guide 26 is disengaged from between the first and second base panels B2, B1 of the carton as it is conveyed downstream. The pair of conveyors 12 convey the cartons downstream such that the cartons C are slidingly moved beyond a free downstream end of the moveable guide 26. Once the carton C passes through the locking station L it is moved on, downstream, for further

30 processing.

In the event of a stoppage in the packaging system it may be necessary or desirable to remove a partially locked carton C disposed within the locking station L before restarting the packaging system. Such a stoppage may be the result of ordinary routine maintenance or operation of the packaging system or may be necessitated by an error, such as a misfed carton C or article. It is desirable to remove any partially locked carton C disposed within the locking station L before restarting the packaging system since restarting the packaging system with a partially locked carton C disposed within the locking station L may jam the partially locked carton C within the locking station L upon restarting the packaging system, thus leading to the need to remove the partially locked carton C from the locking station L irrespective of whether said carton C was the reason for the original stoppage.

In order to facilitate removal of the partially locked carton C from the locking station L the locking station L is provided with the moveable guide 26. In the event of a stoppage the moveable guide 26 is moved to a second position as shown in Figures 5 and 6. The movable guide 26 is moved to an upstream position in which the moveable guide 26 is retracted within the elongate recess 17; this is achieved by extending the piston 30 outwardly from the cylinder 22. In doing so, the arm 28 follows the elongate slot 18. In this stowed or release position the moveable guide 26 is retracted from its position between the first base panel B2 and the second base panel B1 of the partially locked carton C. The carton C is released from the moveable guide 26.

In the illustrated embodiment, the carton C is picked up and moved upwardly from the locking station L, as indicated by direction arrow D7. In this embodiment the conveyors 12 and consequently lug assemblies 14a, 14b are moved outwardly (transversely with respect to the direction of carton flow), away from one another, as indicated by direction arrows D5 and D6, to widen the gap therebetween. Consequently, the lug assemblies 14a, 14b are withdrawn from the apertures in each side of the carton C, allowing the carton C to be lifted up, either manually by an operator or automatically by a picker mechanism (not shown). It is envisaged that the pair of conveyors 12 may be moved simultaneously with the moveable guide 26. In some embodiments movement of the movable guide 26 upstream to the second position and/or movement of the pair of conveyors 12 outwardly is triggered manually by an operator. In other embodiments the movement of the movable guide 26 upstream to the second position and/or movement of the pair of conveyors 12 outwardly is triggered automatically in response to the packaging system detecting stoppage or error in the system.

It can be appreciated that various changes may be made within the scope of the present invention. For example, the size and shape of the panels and apertures may be adjusted to accommodate articles of differing size or shape. In other embodiments of the invention, the piston 30 and cylinder assembly 22 may be replaced by an alternative actuator for moving the moveable guide 26, for example by rack and pinion system or worm gear system driven by an electric motor. In some embodiments of the invention, the cylinder assembly 22 may be located upstream with respect to the piston 30; in such embodiments the moveable guide 26 is in a carton release position when the piston 30 is retracted within the cylinder assembly 22.

It will be recognised that as used herein, directional references such as "top", "bottom", "front", "back", "end", "side", "inner", "outer", "upper" and "lower" do not limit the respective panels to such orientation, but merely serve to distinguish these panels from one another.

As used herein, the terms "hinged connection" and "fold line" refers to all manner of lines that define hinge features of the blank, facilitate folding portions of the blank with respect to one another, or otherwise indicate optimal panel folding locations for the blank. A fold line is typically a scored line, an embossed line, or a debossed line. Any reference to hinged connection or fold line should not be construed as necessarily referring to a single fold line only; indeed it is envisaged that hinged connection can be formed from any one or more of the following, a short slit, a frangible line or a fold line, without departing from the scope of the invention.

Claims

An apparatus for packaging one or more articles in a carton, the carton comprising a plurality of panels, the apparatus comprising at least one conveyor for conveying cartons to a locking station, the locking station comprising at least one fixed guide member for guiding a pair of panels of each carton into an overlapping relationship and a moveable guide member for maintaining a first one of the pair of panels in a folded position, a second one of the pair of panels is folded into overlapping relationship therewith, the moveable guide member being moveable with respect to the fixed guide member, so as to disengage the moveable guide member from engagement with the carton.

An apparatus according to claim 1 , wherein the moveable guide member is moved from a first, operative, position to a second, release, position to facilitate removal of a carton from the locking station in the event of a stoppage in a system of which the apparatus is a part.

An apparatus according to claim 1 , wherein the moveable guide member is disposed in a first, operative, position to form a continuous guide with the at least one fixed guide member for locking the pair of panels together and wherein the moveable guide member is disposed in a second, release, position to form a gateway between the at least one fixed guide and the moveable guide for facilitating removal of a carton from the locking station through the gateway in the event of a stoppage in a system of which the apparatus is a part.

An apparatus according to claim 1 , wherein the at least one fixed guide comprises a first guide member disposed at an upstream location and a second guide member disposed at a downstream location, such that when the moveable guide is disposed in a first, operative, position the first guide member is disposed at an upstream end of the moveable guide member and the second guide member is disposed at a downstream end of the moveable guide member.

An apparatus according to any of claims 1 to 4, wherein the moveable guide comprises a downstream terminus arranged such that cartons may be disengaged from the moveable guide by slidably moving the cartons downstream.

6. An apparatus according to any of claims 1 to 5, wherein the moveable guide is moved in an upstream direction to a release position in order to remove a carton from the locking station.

7. An apparatus according to any of claims 1 to 6, wherein the first guide member comprises a recess for receiving the moveable guide member when disposed in a second, stowed or release, position.

8. An apparatus according to any of claims 1 to 7, wherein the first guide member comprises an elongate slot for receiving a follower coupled to the moveable guide member thereby controlling movement of the moveable guide member.

9. An apparatus according to any of claims 1 to 8, wherein the at least one fixed guide comprises a folding guide member which is arranged to have an engaging edge which is divergently arranged with respect to the movable guide.

10. An apparatus according to claim 9, wherein the folding guide extends under or over the moveable guide so as to wrap the carton about the moveable guide.

1 1 . An apparatus according to claim 9 or 10, wherein the folding guide folds the second panel such that the moveable guide is disposed between the first and second panels.

12. An apparatus according to claim 1 1 , wherein the second panel is wrapped at least partially about the moveable guide.

13. An apparatus according to claim 1 , wherein the second panel is folded into overlapping relationship with the first panel whilst being conveyed through the locking station.

14. An apparatus according to any of claims 1 to 13, wherein the moveable guide member is tapered at a downstream end.

15. An apparatus according to any of claims 1 to 14, wherein the moveable guide member comprises a lower edge which is chamfered at the downstream end.

16. An apparatus according to any of claims 1 to 15, wherein the second guide member comprises an inclined ramp shaped complementary to the moveable guide member such that when in the first, operative position the moveable guide mates with the second guide member such that an upper edge of the movable guide and an upper edge of the second guide member are flush with one another.

17. An apparatus according to any of claims 1 to 16, wherein the second guide member comprises an inclined ramp shaped to bring the second panel into face contacting relationship with the first panel as the carton is conveyed downstream.

18. An apparatus according to any of claims 1 to 17, wherein the moveable guide is coupled to an actuator such as a piston and cylinder arrangement.

19. An apparatus according to any of claims 1 to 18, wherein the apparatus comprises a pair of conveyors disposed on opposing sides of the carton for conveying the carton to the locking station.

20. An apparatus according to claim 19, wherein each of the pair of conveyors comprises a lug assembly for engaging with the carton.

21 . An apparatus according to claim 19 or 20, wherein the pair of conveyors are moveable in a direction transverse to the direction of article travel such that the gap between the conveyors can be widened to release the carton from the conveyors.

22. A method of packaging articles comprising:

conveying a carton to a locking station upon a conveyor forming part of a packaging system;

folding a first panel of the carton about one or more articles being packaged into a folded position;

maintaining the first panel in the folded position with a guide member;

detecting a stoppage of the packaging system; and

removing the carton from the locking station.

23. A method of packaging articles according to claim 22, wherein the method comprises:

restarting operation of the packaging system, and conveying a subsequent article to the locking station.

24. A method of packaging articles according to claim 23, wherein the restarting operation of the packaging system comprises:

moving the moveable element so as to mate with a fixed element of the guide member, such that the fixed element and the moveable element together form a continuous guide member.

25. A method of packaging articles according to claim 22, wherein moving the moveable element comprises:

26. A packaging machine comprising the apparatus of claims 1 to 21 , for carrying out the method of claims 22 to 25.