WO1999037540A2

WO1999037540A2 - Method of and apparatus for packaging infusion packages

Info

Publication number: WO1999037540A2
Application number: PCT/GB1999/000221
Authority: WO
Inventors: Paul Utz; Paul Wollmershäuser; Gerald Schubert; David John Wilkinson; Stephen John Richard Lobley
Original assignee: Tetley Gb Ltd.
Priority date: 1998-01-22
Filing date: 1999-01-22
Publication date: 1999-07-29
Also published as: GB9801395D0; GB2349129A; GB9809424D0; AU2177999A; GB2349129B; GB0018026D0; DE19982707T1; WO1999037540A3

Abstract

Infusion packages are produced in a machine (2) and stacked in carriers (6). The carriers (6) are conveyed to a vibration station (18) where the stacks of infusion packages are vibrated by displacing them reciprocally in a vertical direction so as to consolidate them. The carriers are then conveyed to a transfer means (10) where the stacks of packages are transferred into transfer chambers which move the stacks to overlie open-mouthed flat-bottomed, flexible bags (12), into which the packages are deposited. The stacks of packages are urged together so as to interleave or otherwise consolidate them as they are transferred into the transfer chambers.

Description

Method of and Apparatus for Packaging Infusion Packages

The present invention relates to a method of, and an apparatus for, packaging infusion packages, such as tea bags, coffee bags and the like.

Infusion packages are often stacked in vertical columns which are then placed in a carton in an automated process. This provides the advantage that the packages are neatly and efficiently arranged in the carton. The carton itself provides a more rigid structure which can support the infusion packages .

One problem with packaging infusion packages in a carton in this manner is that the carton will often be deeper than the height of the columns of infusion packages that it contains, so that there is a gap above the columns in the carton. Such a gap is undesirable, since it means that the carton occupies more space than is strictly necessary (e.g. when packed for transit or on shelves in a shop) . The carton must also be sufficiently robust to resist collapsing into the gap, e.g. when stacked.

This problem arises because the density of a particular infusion will in practice vary between batches (typically over periods of days or weeks) . This means that it is not readily possible to ensure that stacks of a particular number of infusion packages containing the infusion will always have the same height. To accommodate any height variations that might occur without the need to change carton sizes, it is necessary to ensure that the carton being used is deep enough to accommodate the highest stack that might reasonably be expected to occur. However, these highest stacks will not occur all the time and thus the carton will often be deeper than the stacks it contains. According to a first aspect of the present invention, there is provided a method of inserting infusion packages into packs, comprising: forming vertical stacks of the infusion packages; vibrating the vertical stacks so as to consolidate them; placing a predetermined number of the consolidated stacks into an open topped, flat-bottomed flexible bag configured closely to surround the stack or stacks of packages ; and closing the top of the bag closely over the stack or stacks of infusion packages therein.

According to a second aspect of the present invention, there is provided an apparatus for inserting infusion packages into packs, comprising: means for forming vertical stacks of the infusion packages ; means for vibrating the stacks so as to consolidate them; means for placing a predetermined number of the consolidated stacks into an open-topped, flat-bottomed flexible bag; and means for closing the top of the bag.

In the present invention vertical stacks of horizontally orientated infusion packages are vibrated to consolidate them and then placed in a flat-bottomed flexible bag. The Applicants have found that by vibrating vertical stacks of infusion packages they can be consolidated to form relatively rigid, stable columns that resist vertical compression. Furthermore, when such columns are placed in a flat-bottomed flexible bag configured closely to surround them, a stable and relatively rigid structure is formed that will stand stably on its flat base and support a vertical load, even though the individual components of infusion packages and the flexible bag in themselves lack strength and rigidity.

The present invention thus provides flexible bags packed with vertical stacks of infusion packages which behave in a similar manner to a carton, i.e. they have strength and rigidity, such that there is no need to enclose them in a more rigid, carton-like structure. This therefore permits a flexible bag alone to be used to contain the infusion packages. This has the advantage that a single size of flexible bag can accommodate variations in stack height because the flexible sides of the bag can more easily be closed closely over the stacks that are placed in it . The use of a flexible bag is also advantageous in that it can be more easily resealed than a carton (e.g. by rolling or folding down its top) . It is also believed that flexible bags may be more attractive to consumers than cartons.

The stacks of infusion packages, which usually will comprise a predetermined number of packages, are preferably vibrated by displacing the stacks reciprocally in the vertical direction only (i.e. along the longitudinal axis of the stacks) . This has been found to be a particularly effective way of consolidating the stacks. Preferably the vibration amplitude is 1^-4mm peak to peak and at a frequency of 1500 to 3000 cycles per minute. Preferred parameters are a displacement of 1.5mm peak to peak and a frequency of 1800-2200 cycles per minute. The duration of the vibration is preferably between 2-20 and most preferably 11-13 seconds. The above parameters have been found to be particularly suitable for stacks of around 40 infusion packages.

In a particularly preferred embodiment downwards pressure is applied to the top of the stacks whilst they are being vibrated. This has been found to help the rate of consolidation and increase the solidity of the consolidated stacks. Preferably, this is achieved by resting a weight on the top of the stacks while they are vibrated. A mass of 120-170g, preferably 150g has been found to be most suitable. Too light a weight does not increase consolidation, whereas too heavy a weight hinders it by hindering the movement of infusion in the packages as they are vibrated. In a particularly preferred arrangement for vibrating the stacks of infusion packages, plural stacks of infusion packages are arranged successively in carriers having vertical stack receiving passages defined therein and all the stacks in a particular carrier vibrated simultaneously. This is a convenient way of collating and vibrating plural stacks at once. The stacks in more than one carrier can be vibrated at the same time if desired.

The carriers themselves could be vibrated to vibrate the stacks, but preferably the arrangement is such that the stacks can be vibrated without vibrating the carriers themselves, as this requires less energy and is less noisy. This is preferably achieved by raising the stacks off their supports in the carriers and then vibrating them in their raised positions. This can conveniently be achieved by providing an opening in the base of each stack receiving passage of a size sufficient to allow entry of a piston or the like into the passage, but which also leaves a floor area, e.g. in the form of an annular ledge, on which the stack of packages may rest . The stacks can then be raised off the floor of the passages by pusher means which can be raised through the openings in the base of each stack receiving passage to unseat the stacks . The pusher means can then be vibrated whilst in their raised positions (e.g. by moving them reciprocally in a vertical direction) to vibrate the stacks.

Where the stacks are vibrated whilst in a carrier, downwards pressure can conveniently be applied to them by lowering a weight which is free to move vertically into each stack-receiving passage and resting it on top of the stack of infusion packages therein. It is also preferred to blow or purge gas, e.g. air, through the stack-receiving passages of the carrier as the stacks are vibrated therein. This helps to carry away dust displaced by the vibration, thereby giving cleaner looking stacks .

Where two or more stacks of infusion packages are to be placed in a single flexible bag, preferably the consolidated stacks of infusion packages are urged together laterally so as to interleave or otherwise consolidate them before they are placed into the flexible bag. This has been found by the Applicants to further increase the stability, integrity and rigidity of the stack structure. This is desirable both from the consumer's point of view and from the point of view of maintaining a desired shape of container where a flexible container is used. It also allows the stacks to be deposited into a bag having a smaller cross- sectional area. Indeed it is believed that interleaved stacks may in themselves provide sufficient rigidity and load bearing structure to a flexible pack.

Thus according to a third aspect of the present invention, there is provided a method of packaging infusion packages, comprising: forming vertical stacks of the infusion packages; urging two or more of the vertical stacks together so as to interleave them along their adjoining sides; placing the urged together stacks into an open topped, flat-bottomed flexible bag configured closely to surround the stack of packages; and closing the top of the bag closely over the stacks of infusion packages therein.

According to a fourth aspect of the present invention, there is provided an apparatus for inserting infusion packages into packs, comprising: means for forming vertical stacks of the infusion packages; means for urging two or more of the vertical stacks together so as to interleave ^'them along their adjoining sides ; means for placing the urged together stacks into an open-topped, flat-bottomed flexible bag; and means for closing the top of the bag.

The stacks of infusion packages are preferably interleaved such that they overlap at their adjoining or adjacent sides by around 7% of their diameters at the distance of greatest overlap. The stacks are preferably urged together by pushing a predetermined number of stacks through or into a tapered aperture or guide before they are transferred into the flexible bag. This can conveniently be achieved in the preferred embodiment where the stacks are vibrated in a carrier by pushing the predetermined number of stacks out of the carrier through the tapered aperture or guide .

The stacks could be transferred straight into the flexible bags once they have been vibrated; for example by dropping them directly from the carriers into the bags. However, they are preferably transferred into an intermediate transfer means which receives the predetermined number of stacks and moves them to a position from where they are deposited into the bags. The transfer means can conveniently be tapered or have a tapered aperture or entrance to urge the stacks together. Alternatively the stacks can be pushed through a tapered guide before they enter the transfer means . The stacks of infusion packages can instead or also be urged together as they are transferred from the transfer means into the flexible bag, e.g. by passing them through a tapered guide . Urging the stacks together further as they are transferred from the transfer means into the flexible bag is particularly suitable where a larger number (e.g. 4 or 6) stacks are to be urged together, i.e. there is more overall movement of the stacks necessary to consolidate them, as it permits that movement and the corresponding applied force to take place in two stages of less movement and force, i.e. as the stacks enter and leave the transfer means .

Where the stacks are vibrated in a carrier, the intermediate transfer means preferably comprises a stack receiving transfer chamber which is positionable above the carriers and into which the stacks can be introduced from below. The stacks are preferably pushed through a tapered guide into the chamber, or the chamber preferably is tapered or has a tapered entrance, to urge the stacks together. The transfer chamber may comprise plural elongate fingers which are able to hold and retain the stacks of packages against the force of gravity.

The stacks of packages may be placed in the bag by inserting the transfer chamber into the open bag and then withdrawing the chamber whilst leaving the packages in place. This arrangement helps to avoid any disruption to the stacks that might occur if they are dropped into the bags. It is particularly applicable where the transfer chamber comprises plural elongate fingers for holding the stacks. A plate or similar may be engaged against the tops of the stacks as the chamber is withdrawn to help retain them in the bag against the movement of the chamber walls or fingers.

When the stacks of packages have been placed in a bag, it should be closed closely over them to minimise any gap between the bag top and the top of the stack or stacks of infusion packages . The bag may be closed in any suitable way known in the art . Preferably the bag is closed by folding it in such a way as to provide a fin on the bag top. This fin can then be rolled or folded over by a user to re-seal the bag after opening. In a preferred embodiment the closing operation is such that each surface of the bag is constrained to remain substantially planar as the top is folded to close the bag (and form the fin, if present) . This reduces the tendency of the flexible bag walls to distort as the bag is folded, which could result in a less snug closure around the stacks of infusion packages or disturb the infusion packages. The restraining of the bag sides in this manner thus enables the bag to be folded effectively as if it had preformed creases where it is to be folded. This allows the bag to be closed closely over the infusion packages and a flatter top for the bag to be produced.

This constraining can be achieved by appropriate arrangement of walls against which the bag sides will abut during the closing process and vacuum plates for gripping the sides of the bag.

Preferably the bag is sealed (e.g. by heat or ultrasound) immediately it is closed (e.g. the fin is formed, if present) , as otherwise the resilience of the bag can cause it to tend to try to reopen. An advantage of the present invention is that because the flexible bags are stable and load supporting, any secondary packaging for transporting or displaying them does not in itself need to be load supporting and can therefore be lighter in weight, less expensive and more easily handled.

A preferred form of such secondary packaging comprises a rectangular tray having a raised rim which is higher along the back of the tray than along the other sides, but which is lower than the other sides at the front of the tray. The higher rear rim helps to substantially prevent the bags on the tray toppling over that side of the tray. The lower front rim permits easy access to bags on the tray and good sight of the artwork on bags in the tray. This tray can be used both to transport the packages and to display them for sale. In a particularly preferred arrangement of the secondary packaging a filled tray or trays (e.g. in a stacked arrangement) are covered with a substantially U- shaped hood which rests on the top surface of the flexible bags in the tray or trays and slides over the outer sides of the tray or trays. The hood provides additional protection to the flexible bags and when so arranged is able to telescope relative to the tray sides so as to accommodate variations in the height of the filled tray or trays e.g. due to tea density variability, variability of the manufacturing process, and/or settlement during distribution and storage of the product .

The flexible bags to be used in the present invention may conveniently be made of paper, coated paper, plastics, metal foil, or laminates composed of some or all of these materials. As noted above, the invention allows a stable, self-supporting flat-bottomed flexible bag containing stacks of infusion packages. The pack can also be, and preferably is, formed initially with a substantially flat, horizontal, closed top, with any fin folded to lie flat on the top of the bag. Such a pack has the advantage that due to its configuration and the uniformity and density of the stacks of packages therein, it is suitable for stacking, which is important for distribution, storage and at the point of sale. Thus according to a further aspect of the present invention there is provided a flexible, flat-bottomed bag containing stacks of infusion packages, said stacks having been packed into the bag by a method in accordance with the present invention. According to another aspect of the present invention there is provided a flat-bottomed flexible bag containing vertical stacks of infusion packages that are arranged to be self-supporting and substantially resistant to compression in the vertical direction, whereby a substantially stable, load bearing bag is provided.

According to a yet further aspect of the present invention there is provided a flat-bottomed flexible bag containing stacks of infusion packages that are interleaved along substantially the entire length of their adjoining sides. A number of preferred embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a schematic general arrangement of apparatus in accordance with the invention;

Figure 2 shows, schematically, infusion packages being produced and stacked;

Figures 3a and 3b show a stack of infusion packages being loaded into a carrier; Figure 4 shows a front, part sectional view of carriers arranged at the vibration station;

Figure 5 shows a front, part sectional view, of stacks of infusion packages being vibrated at the vibration station; Figure 6 shows a side sectional view of stacks of infusion packages being vibrated at the vibration station;

Figure 7a shows a stack of infusion packages that has not been consolidated; Figure 7b shows a consolidated stack of infusion packages;

Figure 8 shows a front, sectional view of carriers arranged under the transfer chambers;

Figures 9a and 9b show the stack control device of Figure 8;

Figure 10 shows the interleaving guide of Figure 8; Figure 11 shows a front, sectional view of stacks of infusion packages being pushed into the transfer chambers of Figure 8 ; Figure 12 shows a side, sectional view of stacks of infusion packages being pushed into the transfer chambers of Figure 8 ; Figure 13 shows a front view of the stacks within ' the transfer chambers of Figure 8;

Figures 14, 15, 16, 17 and 18 show the transfer chambers of Figure 8 arranged above the containers and the depositing of the stacks of infusion packages into the containers; and

Figure 19 shows a horizontal cross-section along the line A-A in Figure 15;

Figure 20 shows a top view of the filled bag in Figure 17 without the transfer chamber;

Figure 21 shows schematically one mode of operation of apparatus embodying the invention;

Figure 22 shows an end view of the bag closing arrangement prior to commencing the closing operation; Figure 23 shows an end view of the bag closing arrangement during the closing operation;

Figure 24 shows an end view of the bag closing arrangement at the end of the closing operation;

Figure 25 shows an end view of the bag closing arrangement after a bag has been closed;

Figure 26 shows a closed bag in a cassette;

Figure 27 shows a pack of infusion packages which has been packed in accordance with the invention;

Figure 28a shows a tray for receiving bags filled in accordance with the present invention;

Figure 28b shows a blank for the tray of Figure 28a;

Figure 29a shows a hood for covering the tray of Figure 28a; Figure 29b shows a blank for the hood of Figure

29a;

Figures 30a and 30b show an assembled tray and hood arrangement ;

Figures 31, 32 and 33 show an alternative transfer chamber arrangement ; and

Figure 34 shows schematically the stacks of infusion packages within the transfer chamber arrangement of Figures 31, 32 and 33.

With reference to Figure 1, an apparatus for manufacturing and packing circular infusion packages comprises in general terms, an infusion package manufacturing machine 2, and a stacking station 4, at which stacks of infusion packages are loaded into carriers 6. Loaded carriers 6 are transported by a conveyor 8 to a vibration station or means 18 where they are vibrated to consolidate them and thence to a transfer station 10 where stacks of packages are removed from the carriers 6 and deposited in open topped flexible flat-bottomed, block-bottomed bags 12 passing along a conveyor 14. The bags are carried in cassettes (not shown) on the conveyor 14 and are delivered by the conveyor 14 to a bag closing means 15 where the bags are closed. Emptied carriers 6 are returned for re-filling by a further conveyor 16.

With reference to Figures 2, 3a and 3b, the infusion packages, in this case tea bags, are produced on a standard IMA C50 or C51 machine, modified in accordance with the teachings of our earlier patent EP 422157 to produce circular packages. Infusion beverage such as tea leaves, coffee grounds, chamomile, etc, is dosed in piles 20 onto a first horizontally moving travelling porous web 22 by a dosing roller 24 and a second porous web 26 is then sealed over the first web 22 by heat sealing rollers 28 to produce a travelling two-ply web 30 having two rows of discrete infusion containing pockets 32. Circular infusion packages 34 are cut from the travelling web by cutting rollers 36 and the packages 34 are pushed downwardly in a horizontal orientation from the web 30 into a pair of adjacent vertically arranged collation tubes 38 by a reciprocating arm 40. Waste web is collected by a vacuum head 41. Only one of the tubes 38 is shown in Figures. 2 and 3, the other lying directly behind it into the plane of the Figure . Although the infusion packages have been described as being formed from two separate webs, as is known in the art they can equally be formed by folding a single web over itself to form a two-ply web. Carriers 6 are passed under the collation tubes 38 to receive stacks 42 of infusion packages therefrom. As can be seen from Figure 1, the carrier 6 has six open bottomed bores 44 arranged in three rows of two for receiving six stacks 42 of infusion packages in total. The carrier 6 is indexed in a stepwise manner under the collation tubes 38, so that successive pairs of bores 44 lie directly thereunder to receive successive pairs of stacks 42. If desired, a detector such as a photocell arrangement can be used to check that the stack receiving bores 44 of the carriers are empty before they are filled.

The carrier 6 is, for example, a machined or moulded block of plastic or other material.

Infusion packages 34 entering the collation tubes 38 are prevented from falling out of the bottom of the tubes 38 by fingers 46 which project inwardly through slots 48 in the tube walls 50 and which move down the length of the tubes 38 as the tubes 38 are filled. As the stacks of infusion packages are formed, a plunger 52 is inserted from below into each tube 38, passing up through the bore 44 of the carrier 6 to support the bottom of the stack 42 therein, as shown in Figure 3a. At this point, the fingers 46 are retracted from the tubes 38. Once a predetermined number of packages 34 have been filled into the tubes 38, the fingers 46 are moved to their starting position where they are moved inwardly again to commence formation of the next stack 42, as shown in Figure 3b. The plunger 52 then moves downwardly in a controlled manner to deposit the finished stack 42 of packages 34 in the bore 44 of the carrier. The opening 54 in the base of each bore 44 is sufficiently large to allow passage of the plunger 52 therethrough, but also sufficiently small^' to leave a flange 58 to support the stacks 42.

The plunger 52 is then withdrawn completely from the bore 44, and the carrier 6 then indexed to its next position at which the process is repeated, or a new carrier 6 indexed into position under the tubes 38.

As can be seen in Figure 1, filled carriers 6 are moved by a cross plunger 60 onto the conveyor 8 from where they are moved to the vibration station or means 18. The movement of the carriers 6 along the conveyor 8 is independent of and occurs at the same time as the filling of the next carrier 6.

At the vibration means 18, the filled carriers 6 are queued and in successive groups of three carriers, the stacks of packages in the carriers are vibrated to consolidate them. The stacks in more or less than three carriers could be vibrated simultaneously, if desired. The number of carriers depends upon the cycle time, throughput, etc., of the packaging operation. Figure 4 shows three carriers positioned at the vibration means ready to be vibrated. The vibration means comprises plural push-rods 88 sized so as to be able to pass through the openings 54 in the base of the bores 44 of the carriers. The push-rods 88 are mounted on a frame 90 which can move vertically to raise and lower all the push-rods simultaneously. The push-rods are arranged such that one rod lies under each bore 44 in the three carriers. Thus, as can be seen from Figure 6 there are two rows of push-rods 88. The frame 90 can be raised and lowered smoothly to move the push-rods 88 into and out of the bores 44. However, it can also be caused to oscillate reciprocally in a vertical direction by means of a motor driven eccentric cam and captive (or non-captive) follower arrangement. It is this oscillating movement which vibrates the stacks of infusion packages, as will be explained further below. Mounted above the carriers 6 at the vibration means are plural pistons 92 arranged to oppose each of the push-rods 88. The pistons 92 are carried on a frame 94 which is moveable vertically to lower the pistons into the bores 44 from above and to raise them out of the bores 44. The pistons 92 slide freely in holes in the frame such that they are free to move vertically relative to the frame 94. They are retained in the frame by means of flanges 96 on their ends. The pistons 92 are used as weights which rest on top of the stacks of packages as they are vibrated. This has been found to help the consolidation process. The pistons have a mass of around 150g, although 120-170g is suitable. A spring arrangement could be used instead of the pistons 92, if desired.

To vibrate the stacks of packages, when three carriers are appropriately positioned and stationary above the push-rods 88, the frame 90 is raised to raise the push-rods into the bores 44 to unseat the stacks 42 from the floors of the bores. Simultaneously the frame

94 is lowered to rest the pistons 92 on the tops of the stacks 42. The pistons should rest on the stacks such that their ends protrude above the frame 94, so that they are free to reciprocate vertically relative to the frame 94.

The push-rods 88 are then caused to reciprocate vertically whilst in their raised positions while the pistons 92 rest on the stacks, to vibrate the stacks 42 vertically. As the push-rods 88 vibrate up and down, the stacks and pistons 92 move correspondingly. Because the stacks are unseated from the bores 44, they are vibrated independently of the carriers 6. Figure 5 shows a front and Figure 6 an end view of the arrangement as the stacks are being vibrated. The amplitude of vibration is preferably around 1 - 4mm peak to peak and at a frequency of 1500 to 3000 cycles per minute. Preferred parameters are a displacement of 1.5mm and a frequency of 1800-2200 cycles per minutes. The duration of vibration is preferably between 2 to 20 seconds and most preferably 11-13 seconds. The vibration should be such that the stacks do not touch the base of the bores 44 during it . The vibration arrangement can further include means for collecting and extracting dust, such as collector hoods and troughs in the vicinity of the top and bottom apertures of the carriers where they are vibrated, if desired. Air is also preferably purged through the stack-receiving passages throughout the vibration operation in order to remove displaced dust. This is particularly useful to help to provide clean looking stacks, which is desirable from a consumer standpoint. The vibration induces gentle sideways translation of the infusion in the infusion packages and thus a more uniform infusion layer, thereby giving firmer, more stable and load bearing stacks of infusion packages in spite of the inherently floppy nature of the packages . The vibration also reduces the height of the stacks and ensures more uniformity of the stack heights, as the infusion is more evenly distributed.

Figures 7a and 7b, illustrate the effect of the vibration on a stack of infusion packages. Figure 7a shows a stack which has not been vibrated. Figure 7b shows a stack after it has been vibrated to consolidate it. The stack in Figure 7b is stable, resistant to toppling over when subject to sideways forces, will stand up erect (i.e. has no tendency to lean) and be self-supporting, and substantially will not compress in the vertical direction.

After the stacks have been vibrated, the frames 90 and 94 are moved away from the carriers to withdraw the push-rods 88 and pistons 92 from the bores and to return the consolidated stacks to being supported by the floors of the bores 44 of the carriers. This movement should be done so as substantially not to disturb the consolidated stacks. The three carriers are then moved by the conveyor 8 to the transfer means 10. The next three carriers are then queued at the vibration means 18 and vibrated, and so on. The carriers 6 are queued at the end of the conveyor 8 (which is of a type which will allow the carriers in the queue to slip on its upper surface) at the transfer station 10, before being pushed onto a transfer feed conveyor 62 by a piston 64. In the embodiment shown, two carriers 6 are pushed across together onto the feed conveyor 62, but of course only one, or even more, could be so moved if desired.

The transfer feed conveyor 62 moves the carriers 6 under a transfer head 70, shown in Figures 8 to 19. The conveyor 62 has indexing means associated with it so that the carriers 6 may be held in a desired position relative to the head 70, and indexed in a stepwise manner relative thereto. In the embodiment shown, two carriers 6 are released at a time and positioned together under the head 70. Other arrangements are possible, such as providing two separate pairs of carriers, one pair for each transfer chamber (of two) (see below) of the transfer head.

The transfer head 70 is mounted on the end of a robotic arm (not shown) and comprises a pair of transfer chambers 74. The transfer chambers should be spaced apart from each other in accordance with e.g. the possible size of containers to be filled, the number of carriers to be positioned below each chamber at any one time, the desired spacings of the containers for subsequent packaging operations on them, the need to accommodate the operation of other mechanisms, and/or the desired flexibility of the process (e.g. as regards filling different sizes of container without the need to adjust or change the transfer head), etc. Thus, for example, where it is desired to be able to fill containers with one, two, four or six stacks of infusion packages using the same basic transfer head arrangement (albeit with different sized transfer chambers) and subsequent packaging arrangements, and six-bore carriers, the transfer chambers and containers are preferably spaced-apart by at least almost the length of two carriers (and two carriers are provided for each transfer chamber at any one time) .

Each chamber 74 is substantially rectangular in section, is open-sided and comprises plural elongate fingers 140 which are arranged to be able to grip stacks of infusion packages pushed between them. The fingers can be arranged around the outside of the chamber and within the chamber, as necessary, to hold the stacks. The fingers 140 have toothed or serrated projections 142 on their stack contacting surfaces to help grip the stacks. The teeth should be configured so as to grip the infusion packages satisfactorily, but without damaging them.

A stack control device 144 in the form of a plate having stops 146 mounted thereon arranged in the same array as the bores in a carrier is mounted transversely in the chamber 74 for movement up and down within the outer fingers 140 by an actuating means 148, such as a pneumatic piston or an electrical drive means. The stops 146 on the control device 144 act as a stop against which the stacks 42 will be lightly pressed during their loading into the fingers 140 and, as will be explained further below, as a means for assisting removal of the stacks 42 of packages from the fingers 140 in the bags 12.

Figures 9a and 9b show the control device 144 and stops 146 in more detail. Figure 9a is an underneath plan view. The device includes holes 150 and relieved regions 152 to prevent interference with the fingers 140 as it is moved. Figure 9b is a side view of the control device .

Below the transfer head 70 is arranged a pair of parallel rails 82 on which are mounted a number of plungers 84 arranged in the same array as the bores 44 in the carriers 6. The heads 86 of the plungers 84 are of such a size that they may pass through the openings in the bores 44 to lift the stacks 42 therein.

At the transfer head there is also provided an interleaving guide 154 to urge the stacks together which is fixedly mounted on the machine frame. The guide is shown in more detail in Figure 10. It is, of course, unnecessary where only a single stack is being filled into the chamber of the transfer head. The guide 154 includes a passage 156 that is shaped to correspond with the composite shape of the group of stacks . The passage 156 tapers slightly, being narrower at the top than at the bottom. Openings 158 around the sides of the interleaving guide 154 may be provided to reduce friction and facilitate the removal of jammed infusion packages .

When the carriers are indexed into position under the transfer chambers 74, the position of the various components is as shown in Figure 8. The control device 144 is in a lower position and is moved downwardly to bear lightly on top of the stacks 42. The plungers 84 are then moved vertically upwardly through the openings 54 in the carrier bores 44 to push the stacks 42 through the interleaving guide 154 and into the fingers 140. The control device 144 moves upwardly with the plungers so that the stacks are effectively sandwiched therebetween. The control device 144 should be driven upwardly (i.e. not be just be pushed up by the force of the stacks) at a rate such as to maintain a light pressure on the top of the stacks that is sufficient to keep the stacks level and in alignment with each other. Movement of the stacks so held through the passage 156 in the interleaving guide 154 acts to push the stacks 42 of packages together and interleave them, thereby giving improved stability of the stacks and significantly reducing the space that they occupy.

Figure 11 shows a front view and Figure 12 is a side view of the process as the stacks are being pushed into the fingers of the transfer chamber 74. Figure 13 shows the stacks loaded into the transfer chambers between the fingers 140. The interleaving of the stacks is also completed. The peripheries of some or all of the individual infusion packages are engaged with the toothed projections on the fingers 140. It should be noted that fingers may be provided in the central portion of the chamber as well as around its periphery, if desired, to help hold the stacks more securely. Once the stacks 42 are loaded fully into the fingers 140 the plungers 84 are retracted, the fingers 140 then retaining the stacks 42 in the chamber 74. The plungers 84 are fully retracted from the carriers 6 to allow the carriers 6 to be indexed to their next position, or to allow new carriers to be introduced into position below the head 70. Empty carriers are conveyed back to the stacking means 4 by the conveyor 16.

Before the plungers 84 are retracted, the control device 144 can be locked in relation to the fingers in such a way that the stops 146 remain in contact with the top of the stacks, to ensure that its weight is supported so that it applies no pressure which might cause the stacks to be displaced downwardly.

If desired, the carriers 6 may alternatively be emptied whilst still on the conveyor 8 (see Figure 1) . In this case the conveyor 8 would index the carriers under the transfer head 70 for them to be emptied.

Empty carriers would then be pushed by the piston 64 on to the conveyor 16 for returning to the stacking means 4.

Once the chambers 74 are filled, the robotic arm (not shown) then moves them simultaneously to a position 100 (figure 1) over the tops of the containers into which the stacks are to be inserted. The control device 144 if locked in position, should remain so locked during this operation. As can be seen from Figure 1, the containers 12 which in this embodiment are flexible bags, are fed along a conveyor 14. The spacing or pitch of the containers on conveyor 14 should be selected appropriately for the filling and subsequent packaging operations. The arrangement is preferably such that the same container spacing can be used for plural different container sizes. The transfer chambers may, if desired, be mounted on slides 102, and means (not shown) provided for moving the chambers along the slides to a desired spacing to accommodate any difference in spacing between the bags 12 on the conveyor 14 and the transfer chambers 74 on the transfer head. In this arrangement, as the head is moved into position over the bags 12 by the robotic arm, the chambers are moved apart by the desired amount so that they will be correctly positioned over the open mouths of the bags 12. The flexible bags 12 in which the stacks 42 are deposited have a cross-section configured to retain the stacks in the deposited configuration. The bags 12 are carried along the conveyor 14 in cassettes (not shown) , which may be conveniently made from moulded or machined plastics, which are configured closely to surround the bags . The bags 12 themselves are formed on a form/fill/seal machine but left open-topped and not filled at that machine.

Figure 14 shows the filled chambers 74 positioned over open bags 12 ready to deposit the stacks of infusion packages therein. As can be seen in Figures 14 and 20, in order to facilitate insertion of the stacks into the bags, jaws 110 are provided at the packing position which may be inserted into the open mouth 112 of the bag to hold it open. The jaws 110 can, for example, be pivotally mounted to enter the mouth 112 when the bag 12 is in the appropriate position. The jaws have cut-outs positioned so as to provide clearance for the insertion of the fingers 140 into the bag. Alternatively suction cups could be applied to the outside of the bag to hold it open. If desired plates can also be arranged closely adjacent the sides of the bag to prevent those sides from distorting or bowing outwardly during the filling process. This is particularly applicable to filling larger bags, where the volume of air to be expelled from the bag as it is filled is greater, thereby leading to greater forces trying to distort the bag as it is filled. If plates are employed adjacent the sides of the bag which are transverse to the direction of motion of the conveyor 14, then these plates will need to be arranged to be retractable so that the bags can be moved into and out of the filling position.

Once the transfer head is positioned closely over the bags 12, the fingers 140 carrying the stacks of packages are moved downwardly to fully insert them into the bags 12, as shown in Figure 15. In order to achieve a close fit of the infusion packages in the bag (preferably a slight interference fit) , there should be very little clearance between the fingers 140 and the sides of the bag. This requires accurate positioning of the fingers 140 before they enter the mouths of the bags. Auxiliary guiding means 160 e.g. in the form of rollers 162, e.g. of an elastomeric material, cooperating with guideways 164 which are fixedly mounted on the machine frame, may be provided for this purpose. The guiding means could be on two opposing sides of the assembly or on three or four sides as necessary. The stack control device 144 remains fixed in relation to the fingers 140 throughout the insertion operation.

Figure 19 shows a horizontal cross-section along the line A-A in Figure 15. The positions of the fingers 140 and stacks 42 within the bag can be seen, as can the interleaving and overlapping of the stacks. There is only a small clearance between the fingers and the bag and substantially zero clearance (preferably an interference fit) between the infusion packages and the bag. After the fingers 140 are inserted in the bags 12, they are withdrawn from the bag as shown in Figure 16. However, the stack control device 144 is maintained at a constant depth of engagement in the bag. This serves to prevent the stacks from moving upwardly with the fingers 140 with the result that the stacks are progressively stripped out of the fingers as the fingers travel upwards and therefore remain in the bag. When all the infusion packages have been stripped from out of the fingers, their upward motion is stopped. The position is then as shown in Figure 17. If desired at this stage the stack control device 144 can be caused to further descend into the bag to press the stops 146 on top of the stacks, with or without the incorporation of vibration, in order to further level up the stacks' top surfaces.

Once the stacks 42 have been deposited in the bags 12, the transfer head is moved upwardly to fully disengage the bag and the jaws release the top of the bags, as shown in Figure 18. The head can then be retracted to its original position to be refilled, whereby the process may be repeated. Once the carriers 6 at the transfer head are empty, two further loaded carriers 6 are moved into position under the head 70 and so on. The filled bags are then moved along the conveyor 14 for closing and further bags are moved into the loading position to be filled by the next movement of the head 70.

This arrangement of the transfer process may be advantageous in that it avoids the need to drop the stacks of packages into the flexible bag, and thus any disruption to the stacks that such dropping might cause. The embodiment described above is suitable for filling two bags 12 each with six stacks 42 of packages 34. Of course it would be possible to adapt the machine to operate with a single transfer chamber, but this would not give as high a production rate. Similarly, more chambers could be provided, if required.

Furthermore, the apparatus may easily be modified to fill different numbers of stacks, e.g. one, two or four stacks, into differently sized bags by changing the transfer chambers 74 and the sequence in which the carriers are emptied.

For example it may be desired only to produce bags 12 which have two stacks 42 of packages 34. To achieve that, the transfer chambers may be exchanged for ones that are of a size to accommodate just two stacks of packages . It would be also possible to modify the carriers 6 to a similar configuration, having only two bores 44 in the same configuration as the chambers 74 so that carriers 6 could be moved under each chamber 74 and completely emptied at each loading stage. However, to avoid the need for producing differently sized and shaped carriers for each size of bag 12, the six bore carriers 6 as described above can still be used, with a modification to the sequence in which they are emptied of stacks 42.

With reference to Figure 21 two stacks 42 of packages 34 are to be filled into each bag 12. Two transfer chambers 74' each receiving two stacks 42 of packages are provided on a transfer head, which as shown in Figure 21 are initially placed over bores A, B, C, D in two carriers 6. Four plungers 84 ' are provided which are lifted upwardly to load four stacks of packages into the two chambers 74 ' , the transfer head then moving to a position over the bags 12 which are then filled. The plungers 84' are then fully retracted and moved into position under bores A', B', C, D', and the transfer head then also moved to overlie these bores . The stacks in these bores are filled into the chambers 74 ' which then move over two new bags 12 to fill them. The carriers 6 are then indexed to bring bores E, F, G and H under the transfer chambers 74 ' , which have returned to their original positions and the process repeated.

Thus the plungers 84 ' may be mounted to a carriage which is movable both up and down but also in a direction transversely to the direction of movement of the carriers 6 so that if required plungers can be moved from row to row for emptying selected stacks from the carrier.

It should also be noted that the carrier and transfer chamber arrangements of the present embodiment are able to accommodate different heights of stacks of infusion packages, thereby making the process able to easily handle different stack heights.

The bag closing operation is shown in Figures 22 to 25. Bags containing a single stack of packages are shown in this example, but it is equally applicable to other sizes of bags. Each filled bag 12 is transported in its cassette 170 on the conveyor 14 to a closing station or means 15. The closing means includes folding and sealing jaws 172 and closing plates 174, which can be operated to fold and close the top of the bags to provide a flat, horizontal top with an upstanding fin. Preferably two bags are closed simultaneously to coordinate with the simultaneous filling of two bags at the transfer station, in which case two closing arrangements will be provided at the closing station. Figure 22 shows an end view of the arrangement prior to commencing the closing operation. The bag 12 is moved in its cassette 170 to a position between the jaws 172. The jaws 172 can engage and then pivot to fold horizontal the vertical sides of the bag 12. The jaws 172 each include a flat perforated vacuum plate 176 behind which vacuum can be induced to grip securely the sides of the bag 12 during the closing operation. A heat sealing strip 178 is provided on the top of each of the jaws 172 to seal the bag once closed.

One closing plate 174 arrangement is shown in Figure 22. There is a corresponding opposing closing plate arrangement on the opposite side of the closing means to close the opposing end side of the bag 12. Each closing plate 174 has a triangular configuration and is pivotable about its base edge towards the bag (i.e. into the plane of Figure 22 for the closing plate shown) to fold the end of the bag inwards and horizontal. Each closing plate 174 is reciprocal horizontally on an arm 180 between the positions shown in Figures 22 (not in use) and 23 (the closing position) to permit bags to be brought past its position to or from the closing means. Each closing plate arrangement also includes a vacuum plate 182 which includes feather- edged flexible rubber vacuum suckers and which can grip and hold the end side of the bag below the closing plate 174 as the plate moves during the closing operation. Two spring plates 184 are also provided which can move vertically and can be inserted inside the open top of the bag 12 to help hold the bag sides and form the corner creases during the closing operation. The plates are resiliently biassed inwardly into the position shown, but can be controllable driven apart horizontally at their free ends by an appropriate driving means or arrangement. Alternatively, separate plates could be suspended independently from and powered (e.g. by an air cylinder or other motor means) along a horizontal rail mounted above the closing station to move them laterally during the closing operation, the rail being vertically moveable to facilitate insertion of the plates into the open bag.

It should be noted that the vertical sides of the cassette 170 come up the sides of the bag relatively close to where the horizontal fold lines forming the closed top of the bag will be. The cassette is sized such that there is little or no gap between the sides of the filled bag (whose basal area will be known) and the cassette sides.

In the closing operation, the closing plates 174 are moved on the arms 180 to their closing positions overlapping the end sides of the bag. The vacuum plates 176 on the jaws 172 and the vacuum plates 182 below the closing plates 174 are then actuated to grip securely the sides of the bag that they are immediately adjacent to. A vacuum may also be induced below the cassette 170 (which has a hole in its base for this purpose) to hold the base of the bag 12, if desired.

The effect of these vacuum gripping arrangements is to constrain the bag surfaces that they grip to remain substantially planar as the bag is closed so as to reduce any tendency for the surfaces to bow, collapse or slip which may hinder the closing operation and in particular the stability and structure of the final closed bag, but without the need to rely on the stacks of infusion packages to provide any support during the closing operation. It should be noted that the sides of the cassette 170 also help to constrain undesired movement of the bag sides during the closing operation, due to their close fit with the bag sides (which is important for this reason) . For example the sides 186 resist the bag sides bowing outwards as the top of the bag is pushed inwards and down to close it .

Once the bag sides have been gripped by the vacuum arrangements, the plates 184 are introduced into the top of the bag. They are then forced apart horizontally to engage the sides of the bag. Simultaneously, or thereafter, the jaws 172 and closing plates 174 are pivoted inwardly and down to fold the sides of the bag down over the stacks of infusion packages . As noted above, the vacuum arrangement and cassette 170 resist any undesired movement of the bag sides during the closing operation. Part way through the folding process, once the plates IB have established where the corner creases will form, these plates are allowed to move together to correspond with the inwards pushing of the folding jaws 172. The triangular closing plates 174 are withdrawn at an appropriate moment once the end gable-like regions have been properly formed. Figure 23 shows the closing operation part way through and Figure 24 the positions when the top is finally formed. As the bag is completely closed, the last part of the motion together of the plates is effected by the folding jaws, as can be seen from Figure 24. (The jaws 172 have rebates 188 to allow the plates 184 to remain in position until the jaw motion is completed. The rebates are deep enough that the plates 184 are not actually gripped.) As can be seen from the Figures, the bag is formed with a vertical fin 128.

As soon as the bag is closed and the fin formed, the sealing strips 178 are pressed inwardly to seal the bag (the strips are maintained hot during the closing process but extra pressure is applied at this stage to seal the bag) while the closing pressure is maintained. This is because the resilience of the bag material can tend to reopen it if it is not sealed immediately. This sealing arrangement also permits easy and ready control of sealing pressures, temperatures, times, etc. The seal should be peelable, as this facilitates opening of the bag. To achieve this, the area of the sealing zone may be coated during the manufacture of the material with a heat sealing peelable lacquer or a peelable thermoplastic (of lower melting point than that of the inner surface of the bag material if this surface is thermoplastic) .

The jaws 172 away from the heat sealing strips 178 are made of low thermal conductivity, e.g. plastics, material so that they do not heat up apart from in the region of the heat sealing strips 178. This helps to avoid unwanted heating of the bag 12, which could lead to undesirable effects such as welding of the inside surface of the bag to its contents . For this reason the plastics jaw extends around the heat sealing strip 178 to prevent direct contact between the strip 178 and the horizontal top surface of the closed bag.

After the bag 12 is closed and sealed, the jaws 172 and plates 184 are withdrawn, as shown in Figure 25. The closed bag at this stage appears as shown in Figure 26. It should be noted that the closed height of the bag can be adjusted by moving the jaws 172 and plates 174 vertically relative to the cassettes 170. This should be done to ensure that the bags are always closed closely over the stacks of infusion packages with little or no head space in the closed pack. The flexible nature of the bag walls means that they can easily be folded at slightly different heights. Because nominally identical stacks of infusion packages vary in height over relatively long periods (e.g. due to variations in tea density), preferably the height of each bag's contents is measured before it is closed and the height measurements used to adjust automatically the closed height of the bag to ensure minimum headspace (e.g. in a control loop) if there is a longer term trend towards a different stack height. Height adjustment could also be done manually, if desired.

The closing operation is preferably provided with an appropriate dust extraction arrangement (not shown) as the closing process can expel infusion dust from the stacks of infusion packages as the bags are closed.

The closed bags 12 are then transported to further finishing stations, where, for example, the fins can be trimmed to a uniform height. This can be useful to ensure that any subsequent fin folding stations are presented with standardised bags upon which to perform their respective operations and to help standardise the appearance of the tops of the closed bags. The fins can also be folded over and optionally adhered to the tops of the bags to provide a flat top. These processes can also be automatically height adjusted on the basis of the height measurement of the bag's contents discussed above, if desired.

Releasable resealable adhesive labels can be secured over the bags if desired. Such labels can perform reclosure and/or tamper-evincing functions. The label could, for example, comprise an elongate strip having adhesive regions at each of its ends which can be separated by removing a tear out strip provided in the label when it is desired to open the bag. The label can also include a readherable adhesive portion to allow it to be used repeatedly to reclose the bag after it has been first opened, if desired. A label can also be used to hold the fin flat against the top of the pack. This can conceal the cut edges of the fin from view (which is better from a consumer aesthetics standpoint) and help to render the pack flatter (which is advantageous if the bags are to be stacked) . The techniques for these processes can be any suitable techniques known in the art .

The conveying and movement of carriers and filled bags between the various operation stations is preferably arranged so as to reduce or minimise that motion disturbing the stacks of infusion packages in the carriers or bags (as any such disturbance can detrimentally affect subsequent packaging processes and/or the appearance of the final product) . Thus preferably abrupt changes of direction of movement of the filled carriers and filled bags are kept to a minimum, any indexing of the filled carriers and filled bags is done in relatively longer, slower steps to reduce accelerations on the carriers and bags, and the arrangement is such that the force of any clashes between filled carriers and between filled bags (e.g. in cassettes) is minimised. The operation of the various components of the apparatus may be controlled using a programmable control which will allow the proper coordination of the various operations, or indeed by any other suitable process control .

Figure 27 shows a bag of tea bags packed in accordance with the invention. The bag 120 has a sealed flat, block-bottom 122 which receives two stacks 124 of tea bags, and is packed and closed as described above. The bag is sealed with a peelable heat seal at its upper end, and the elongate fin 128, formed when the bag is first closed, is folded over and held against the top of the pack to form a flatter top 126 by a releasable tamper-evident resealable label 130. The label 130 has an adhesive anchoring pad 131 at each end and a tear-off strip 133 which can be readily removed to release the label material linking the anchoring pads 131, thereby allowing the bag to be opened. The part 135 of the label is provided with a repeatably adherable adhesive strip which can be used to reclose the bag once it has been opened.

Once the bag is opened, as tea bags are removed, the fin can be further folded or rolled down, and retained in a closed position by the part 135 of label 130. This will help to reclose the pack thereby keeping the contents fresher.

An advantage of bags packed in accordance with the present invention is that they are stable and vertical load-supporting. This means that any secondary packaging for the bags does not in itself need to be load bearing, and can therefore be less heavy and less expensive .

Figures 28 to 30 illustrate an embodiment of preferred secondary packaging for bags packed in accordance with the present invention. Figure 28a shows a constructed cardboard tray 98 (and Figure 28b a blank for the tray) in which the bags 12 can be placed. The tray is configured to receive ah integral number of bags. The rim at the rear 102 of the tray is higher than the other sides and is sized so as to substantially prevent the bags from toppling over that side when pushed horizontally against it. The front of the tray on the other hand has a lower centre portion 104 to permit good access to bags in the tray, and good sight of art work on the bags in the tray when looking from that side. The tray sides are joined to each other by tabs

106. The rear tabs are folded over the outside of the rear side of the tray, as this provides better structural support, but the front tabs are adhered to the inside of the front of the tray to provide a neater appearance.

The tray can be used to transport the bags and to display them on a shelf in a shop.

When the tray is used to transport the bags, it is preferably further provided with a protective cardboard hood. A suitable hood 108 is shown constructed in

Figure 29a and as a blank in Figure 29b. The hood is U- shaped and has flanges 114 at its open ends which can be folded over and adhered where they overlap to provide corner pillars. These flanges provide additional protection and structure to the package.

An example of the complete secondary packaging arrangement is shown in Figures 30a and 30b. In this arrangement four filled trays 98 are arranged in two stacked layers, each layer comprising two trays side-by- side. The trays can be stacked in this manner because the bags in them are load supporting.

The hood 108 is sized so as to slide over the outsides of the stacked trays and is placed over the trays such that it rests on the top of the bags in the top trays. As can be seen the hood overlaps the rims of the bottom trays, and can telescope relative to them should the height of the bags in the trays vary (e.g. should the density of the infusion in the stacked infusion packages vary, or there be any settlement of the bags ' contents during transit - the telescoping hood maintains stability of the secondary packs even in these events) .

The assembled head and tray combination can be stretch or shrink overwrapped to provide additional protection and tamper evident protection for the bags visible on the open sides of the hood, if desired. Figures 31, 32 and 33 show an alternative embodiment of the transfer means for transferring the stacks of infusion packages from the carriers to the containers .

In this arrangement the transfer head 70" which is mounted on the end of a robotic arm 72 comprises a pair of transfer chambers 74". Although the transfer chambers are shown schematically close together in the drawings for convenience, they should be spaced apart from each other as discussed in relation to the previous embodiment. Thus, again, for example, where it is desired to be able to fill containers with one, two, four or six stacks of infusion packages using the same basic transfer head arrangement (albeit with different sized transfer chambers) and subsequent packaging arrangements, and six-bore carriers, the transfer chambers and containers are preferably spaced-apart by at least almost the length of two carriers (and two carriers are provided to each chamber at any one time) . Each chamber 74" is substantially rectangular in section and has at its lower end a pair of fixed, tapered, lead-in plates 202 on two opposed sides of the chamber 74". On the other two sides of the lower end of the chamber 74" are pivotally mounted a pair of apertured closure plates 204 which, in their open position taper outwardly away from the base of each chamber 74". The plates 204 are pivoted in use by pneumatic cylinders 206, or other suitable actuators mounted to the head 70".

A plate 208 is mounted transversely in each chamber 74" for movement up and down within the chamber 74" by a pneumatic piston 210 or equivalent actuating means. These plates 208 act as a stop against which the stacks 42 will be lightly pressed during their loading into the chambers 74" and, as will be explained further below, as a means for subsequently discharging the stacks 42 of packages from the chambers 74" into the bags 12. In this arrangement, as before, the carriers are indexed into position under the transfer chambers 74". The position of the various components is then as shown in Figure 31. The plates 208 are in a lower position with the pivoted closure plates 204 open to receive the stacks 42. The plungers 84 are then moved vertically upwardly through the openings in the carrier bores to push the stacks 42 into the chambers 74". The plates 208 move upwardly with the plungers so that the stacks 42 are effectively sandwiched therebetween. The plates 208 should be driven upwardly (i.e. not just be pushed up by the force of the stacks) but at such a rate as to maintain a light pressure on the top of the stacks that is sufficient to keep the stacks level and in alignment with each other. The cross-sectional area of each chamber 74" is smaller than that of the carrier, and is approximately equal to that of the container 12 into which the stacks of packages are to be filled. The tapered lead-in plates 202 and closure plates 204 act to push or urge the stacks 42 of packages together as they are introduced into the chambers 74", thereby bending the peripheral sealed portions of the individual packages in each stack 42 and interleaving the stacks 42 (as shown schematically in Figure 34) to give improved stability of the stacks. Once the stacks 42 are loaded fully into the chambers 74", the pivoted closure plates 204 are moved to their closed positions, around the plunger heads 86, which are then retracted, the portions 212 of the closure plates 204 retaining the stacks 42 in the chamber 74 " .

The plungers 84 are fully retracted from the carriers 6 to allow the carriers 6 to be indexed to their next position, or to allow new carriers to be introduced into position below the head 70".

As before, once the chambers 74" are filled, the robotic arm 72 then moves them together to a position over the open tops of the containers into which the stacks 42 are to be inserted. The spacing or pitch of the containers on conveyor 14 should be selected appropriately for the filling and subsequent packaging operations. The arrangement is preferably such that the same container spacing can be used for plural different container sizes.

The transfer chambers may, if desired, be mounted on slides 102, and means (not shown) provided for moving the chambers along the slides to a desired spacing to accommodate any difference in spacing between the bags on the conveyor 14 and the transfer chambers 74" on the transfer head. In this arrangement, as the head is moved into position over the bags 12 by the robotic arm 72, the chambers are moved apart by the desired amount so that they will be correctly positioned over the open mouth of each bag 12.

Once the transfer head 70" is positioned closely over the bags 12, the closure plates 204 are pivoted to an open position and the stacks are pushed out of the chambers 74" by the plate 208 which is moved downwardly.

This movement is conducted at high acceleration so that the stacks do not have opportunity to fall under gravity into the bags 12, and thereby possibly lose their integrity. Furthermore, plate 208 continues to move downwardly until the bottoms of the stacks reach the bottom of the bag, and is then allowed to dwell on the tops of the stacks for a short period so that individual packages are prevented from being displaced from the stack due to bouncing which might otherwise occur.

Once the stacks 42 have been deposited in the bags 12, the head 70" is retracted to its original position to be refilled, whereby the process may be repeated. Once the carriers 6 at the transfer head are empty, further loaded carriers 6 are moved into position under the head 70" and so on.

Whilst in the above embodiments, circular tea bags are quoted as an example of infusion packages which can be packed by the method of the invention, it is equally applicable to other shapes of packages, such as rectangular packages, non-geometrically shaped packages, etc, including tagged infusion packages. In the case of tagged infusion packages, it may, as will be appreciated by those skilled in the art, be necessary to alternate different orientations of the infusion packages in each stack so as to ensure that the top of the stack lies substantially horizontally, in spite of the extra bulk of the tags.

Claims

1. A method of inserting infusion packages into packs, comprising : forming vertical stacks of the infusion packages; vibrating the vertical stacks so as to consolidate them; placing a predetermined number of the consolidated stacks into an open topped, flat-bottomed flexible bag configured closely to surround the stack or stacks of packages ; and closing the top of the bag closely over the stack or stacks of infusion packages therein.

2. A method as claimed in claim 1, comprising displacing the stacks of infusion packages reciprocally solely in a direction substantially parallel to the longitudinal axis of the stacks to vibrate them.

3. A method as claimed in claim 1 or 2 , wherein the vibration amplitude is l^-4mm peak to peak, the vibration frequency is 1500 to 3000 cycles per minute, and the duration of the vibration is between 2 and 20 seconds .

4. A method as claimed in claim 1, 2 or 3 , further comprising applying downwards pressure to the tops of the stacks whilst they are being vibrated.

5. A method as claimed in claim 4, wherein the downwards pressure is applied by resting a weight on the top of each stack while the stacks are vibrated.

6. A method as claimed in claim 5, wherein a mass of 120-170g is rested on the top of each stack while the stacks are vibrated.

7. A method as claimed in any one of the preceding claims, comprising arranging plural stacks of infusion packages successively in carriers having vertical stack receiving passages defined therein; and vibrating the stacks while they are in the carriers.

8. A method as claimed in claim 7, wherein the stacks in more than one carrier are vibrated at the same time.

9. A method as claimed in claim 7 or 8 , wherein the stacks are vibrated without vibrating the carriers.

10. A method as claimed in claim 9, comprising raising the stacks off their supports in the carriers and then vibrating the stacks in their raised positions.

11. A method as claimed in any one of claims 7 to 10, comprising applying downwards pressure to the stacks while they are vibrated by lowering a weight which is free to move vertically into each stack-receiving passage of the carrier and resting it on top of the stack of infusion packages therein.

12. A method as claimed in any one of claim 7 to 11, further comprising blowing gas through the stack receiving passages to purge them while the stacks are being vibrated therein.

13. A method as claimed in any one of the preceding claims, further comprising urging two or more consolidated stacks of infusion packages together laterally so as to interleave or otherwise consolidate them before they are placed into the flexible bag.

14. A method of packaging infusion packages, comprising: forming vertical stacks of the infusion packages; urging two or more of the vertical stacks together so as to interleave them along their adjoining sides; placing the urged together stacks into an open topped, flat-bottomed flexible bag configured closely to surround the stack of packages; and closing the top of the bag closely over the stacks of infusion packages therein.

15. A method as claimed in claim 13 or 14, wherein the stacks of infusion packages are interleaved such that they overlap at their adjoining sides by around 7% of their diameters at the distance of greatest overlap.

16. A method as claimed in claim 13, 14 or 15, comprising pushing the stacks through or into a tapered aperture or guide to urge them together.

17. A method as claimed in claim 7 and any one of the preceding claims, comprising transferring the stacks of infusion packages from the carriers into an intermediate transfer means which receives the predetermined number of stacks and moves them to a position from where they are deposited into the bags.

18. A method as claimed in claim 17, comprising urging the stacks together as they are transferred into the transfer means.

19. A method as claimed in claim 17 or 18, comprising urging the stacks of infusion packages together as they are transferred from the transfer means into the flexible bag.

20. A method as claimed in any one of the preceding claims, wherein the closing operation is such that each surface of the bag is constrained to remain substantially planar as the top of the bag is folded to close the bag .

21. A method as claimed in any one of the preceding claims, comprising closing the bag such that the closed bag has a substantially flat, horizontal top, except for an upstanding fin, and folding the fin to lie it flat against the top of the bag.

22. A method as claimed in any one of the preceding claims, comprising sealing the bag substantially immediately after it is closed.

23. An apparatus for inserting infusion packages into packs, comprising: means for forming vertical stacks of the infusion packages ; means for vibrating the stacks so as to consolidate them; means for placing a predetermined number of the consolidated stacks into an open-topped, flat-bottomed flexible bag; and means for closing the top of the bag.

24. An apparatus as claimed in claim 23, wherein the vibrating means comprises means for displacing the stacks of infusion packages reciprocally in a direction substantially parallel to the longitudinal axis of the stacks .

25. An apparatus as claimed in claim 23 or 24, further comprising means for applying downwards pressure to the top of each stack whilst the stacks are being vibrated.

26. An apparatus as claimed in claim 25, comprising one or more weights which can be rested on the top of the stacks while the stacks are vibrated.

27. An apparatus as claimed in any one of claims 23 to 26, comprising a plurality of carriers having vertical stack receiving passages defined therein; means for placing plural stacks of infusion packages in successive carriers; and means for vibrating the stacks while they are in the carriers .

28. An apparatus as claimed in claim 27, wherein the carriers comprise an opening in the base of each stack receiving passage of a size sufficient to allow entry of a piston or the like into the passage, but which also leaves a floor area on which the stack of packages may rest .

29. An apparatus as claimed in claim 28, wherein the vibration means includes one or more pushers which can be raised through the openings in the bases of the stack receiving passages to unseat the stacks and raise them off the floor of the passages, which pushers can then be vibrated whilst in their raised positions to vibrate the stacks .

30. An apparatus as claimed in claim 27, 28 or 29, comprising one or more weights which are free to move vertically and can be lowered into the stack-receiving passages of the carriers and rested on top of the stacks of infusion packages therein, whereby downwards pressure can be applied to the stacks of infusion packages as they are vibrated.

31. An apparatus as claimed in claim 27, 28, 29 or 30, further comprising means for blowing gas through the stack receiving passages of the carrier as the stacks of infusion packages are vibrated therein.

32. An apparatus as claimed in any one of claims 23 to 31, further comprising means for urging two or more consolidated stacks of infusion packages together laterally so as to interleave or otherwise consolidate them before they are placed into the flexible bag.

33. An apparatus for inserting infusion packages into packs, comprising: means for forming vertical stacks of the infusion packages; means for urging two or more of the vertical stacks together so as to interleave them along their adjoining sides; means for placing the urged together stacks into an open-topped, flat-bottomed flexible bag; and means for closing the top of the bag.

34. An apparatus as claimed in claim 32 or 33, comprising a tapered aperture or guide through which the stacks can be pushed before they are transferred into the flexible bag so as to urge them together.

35. An apparatus as claimed in any one of claims 23 to 34, further comprising transfer means which can receive the predetermined number of stacks and move them to a position from where they are deposited into the bags.

36. An apparatus as claimed in claim 35, wherein the transfer means has a tapered aperture or entrance to urge the stacks together.

37. An apparatus as claimed in claim 27 and any one of claims 35 and 36, wherein the transfer means comprises a stack receiving transfer chamber which is positionable above the carriers and into which the stacks can be introduced from below.

38. An apparatus as claimed in claim 37, wherein the transfer chamber is tapered or has a tapered entrance, to urge the stacks together.

39. An apparatus as claimed in claim 35 and any one of claims 23 to 38, further comprising means for urging stacks of infusion packages together as they are transferred from the transfer means into the flexible bag.

40. An apparatus as claimed in any one of claims 23 to 39, comprising means for constraining each surface of the bag to remain substantially planar as the top of the bag is folded to close the bag.

41. An apparatus as claimed in any one of claims 23 to 40, further comprising one or more walls against which a side or sides of the bag can abut in use if they distort outwardly during the closing process; and one or more vacuum plates for gripping the sides of the bag during the closing process.

42. A flexible, flat-bottomed bag containing stacks of infusion packages, said stacks having been packed into the bag by a method in accordance with any one of claims 1 to 22, or by using an apparatus in accordance with any one of claims 23 to 41.

43. A flat-bottomed flexible bag containing vertical stacks of infusion packages that are arranged to be self-supporting and substantially resistant to compression in the vertical direction, whereby a stable, load bearing bag is provided.

44. A flat-bottomed flexible bag containing stacks of infusion packages that are interleaved along substantially the entire length of their adjoining sides .

45. A flat-bottomed flexible bag as claimed in claim 42, 43 or 44, which is closed, and sealed by means of a peelable seal joining two of its inner surfaces, wherein the closed and sealed bag has a substantially flat, horizontal top and a fin laid flat on top of the bag.

46. A rectangular tray having a raised rim which is higher along the back of the tray than along the other sides of the tray, the rim at the front of the tray being lower than along the other sides of the tray, and the tray carrying one or more flexible bags as claimed in claim 42, 43, 44 or 45.

47. One or more trays as claimed in claim 46, which are filled with flexible bags and are covered with a substantially U-shaped hood which rests on the top surface of the flexible bags in the tray or trays and slides over the outer sides of the tray or trays.

48. One or more rectangular trays each having a raised rim and filled with flexible bags as claimed in claim 42, 43, 44 or 45, the filled tray or trays being covered with a substantially U-shaped hood which rests on the top surface of the flexible bags in the tray or trays and slides over the outer sides of the tray or trays.