Field of the Invention

The present invention concerns a method for packing articles, liquid or loose material in film bags which are conveyed through a filling station in a continuous web of bag items, wherein the bag openings are kept open for reception of articles after which the bags are closed and separated from the web, by which method the bag web initially and along its opening edges is brought into guiding connection with guide means adapted for retaining and guiding peripheral areas at the opposing bag opening edges along a conveyor path through the filling station, as in connection with this passage the guide means force the bag opening edges apart for successive opening of the bags in the filling station, and then, after filling the bags, joining the bag opening edges for closing the bags, by which method the opposing bag opening edges are mutually unfolded and by which method the bag web is brought to engage the guide means by being conveyed on a support rail, the guide means ensuring retention of the bag web along the conveyor path through the filling station.

The invention furthermore concerns an apparatus for performing such a method, including:

- a filling station in which the bag openings are kept open for reception of articles;

- guide means adapted for retaining and guiding peripheral areas at the opposing outer bag opening edges along a conveyor path through the filling station, as in connection with this passage the guide means force the bag opening edges apart for successive opening of the bags in the filling station, and then, after filling the bags, joining the bag opening edges for closing the bags again;

- a support rail for conveying the bag web for engagement with the guide means.

The invention further concerns a bag web for use by such a method and in such an apparatus, the bag web including a contiguous series of bag items separated by a number of slits extending from a bottom edge of the web to a point below a upper edge of the web, the lateral edges of the webs being closed by welds, and where the bag web includes a central support region extending longitudinally of the bag web, the support region connecting bag items that are disposed side by side transversely of the web.

Background of the Invention

A basic example of this technology is mentioned in EP-696997 in which it is stated that the opposite upper edge areas of the bag item web is made with bent peripheral parts formed by grooves for drawing in on conveyance bars which have a mutual expansion for producing an opening of the bag items in the direction of conveyance, such that these can be filled, for example through a superjacent funnel, whereafter the conveyance bars are narrowed against each other again for temporary closing of the filled bag items. These may then be closed finally by welding below the said duct parts, after which these are cut off and the items are mutually separated. As alternative is specified that instead of the channel parts there may be used edge thickenings that may be received in slotted guide tubes for corresponding conveying of the bag items.

Since then other types of means have been suggested for catching and carrying the opposite upper edges of the bag item web, for example as stated in EP 0 555 321 B where special catching chains are used for the purpose without special requirements to the design of the upper edge areas of the folded bag item web. This is of substantial significance in that as an end product a simple rolled op flat film web without local thicknesses may be used, however in return there are considerable problems with regard to both the guidance of the opposite edges of the bag items for a safe engagement with the chains and with regard to a desirably inexpensive embodiment of these chains.

In EP 0 396 838 and EP 0 825 1 16 it is furthermore stated that a flat pipe web of the film can be applied which can continuously be cut open along its upper edge with integrated unfolding and catching of the thus cut open upper edges without these being specifically designed neither as grooves nor with thickenings which will indicate a distinct simplification of the requirements for the formation of the bag web. The cut up upper edge parts are unfolded for squeezing between respective moved belts, which are formed with longitudinal recesses and corresponding cords for pressing in, whereby a suitably firm carrying engagement can be established. This engagement, however, is not more firm than axial slipping may occur between the upper edges of the bag web and associated belt conveyor means, whereby uncertainty may arise as to whether a conveyed item has been conveyed entirely synchronously with the conveyor belts. Furthermore, deviations with regard to level of the area of the web sides squeezed between the conveyor belts may arise, which can have significance to whether the filled bags are finally closed just on the spot intended for this purpose, e.g. with regard to print on the bag. In EP 1 087 890 is described a technique which uses a simplified flat bag web as said opening edge is merely closed when the web is introduced on a single carrier bar and is continuously cut open in a station whereby the thereby upright peripheral strip parts are unfolded in order to be laid down on opposite chains. These strip parts are made in advance with a row of holes which are moved down onto upwardly pointed holding studs on the carrier chains during folding down whereby a safe carrier and propelling engagement is achieved without any special profiling of the opening edges.

EP 1 451 069 discloses a similar technique. Here, edge strip parts will also be made in advance with a row of holes which are moved down on upwardly directed holding studs on the carrier chains during folding down such that a secure carrier and propelling engagement is achieved without any special profiling of the opening edges.

Common to all these prior art systems, the bag web is conveyed with a series of bag items that are positioned in longitudinal direction and filled successively.

US 2003/0165278 A, EP 1733970 A, US 2004/0134166 A, WO 02/070349 A, and DE 3839336 A all disclose filling of various bag types in bag webs with two bag rows with a central extending support region running longitudinally of the film web. For many years there has been a wish for increasing the rate of filling and for producing the bags more cheaply. It is primarily a wish in connection with the technology of the two latter European patents where the use of studs provide a secure carrier and propelling engagement. However, there is a similar wish in connection with the other described prior art techniques. Object of the Invention

It is the object of the invention to provide a method for packing articles, liquid or loose material in film bags, which in a continuous web are conveyed through a filling station that provides a high filling rate.

A further object of the invention is to indicate a bag web of bag items enabling a high filling rate and cheap production of the bags.

Description of the Invention

According to the present invention, this object is achieved by a method of the kind mentioned in the introduction, and which is peculiar in that the bag web is provided with a central support region extending longitudinally of the bag web, the central support region formed as an entirely or partially closed channel, and where the central support region connect bag items that are disposed side by side transversely of the web, the central support region being conveyed on the support rail along the conveyor path through the filling station, and that peripheral areas at the outermost opposite bag opening edges of two juxtaposed bag items are brought in guiding connection with the guide means.

An apparatus according to the invention is peculiar in that the support rail extends along the conveyor path through the filling station for supporting the bag web at a central support region extending longitudinally of the bag web and connecting bag items that are disposed side by side transversely of the web, as the support rail is adapted for being received in the entirely or partially closed channel in the central support region of the bag web.

A bag web according to the invention includes a central support region extending longitudinally of the bag web and connecting bag items that are disposed side by side transversely of the web, and which is peculiar in that the central support region is formed as an entirely or partially closed channel, and that the peripheral areas at the outermost opposite bag opening edges of two juxtaposed bag items are adapted to be brought into guiding connection with guide means. In a surprisingly simple way it appears to be possible to increase the filling rate significantly and at the same time reduce the price of producing and filling the bags, just by providing a bag web having bag items disposed side by side transversely of the web. The bag web thus appears with two juxtaposed rows of contiguous bag items. These two rows are connected with the central support region extending longitudinally of the bag web.

This central support region is supported on the support rail which is known from the technique in the two European patents EP 1 087 890 and EP 1 451 069. It is only necessary to extend such a support rail so as to extend along the conveyor path through the filling station for supporting the two juxtaposed bag webs in the filling station. Bag items from each of the two rows will be supported by the common central guide rail at their common central support region, and supported by the guide means at each of the peripheral areas at the outermost opposite bag opening edges of two juxtaposed bag items.

When the central support region is formed as an entirely or partially closed channel, a more secure guiding of the bag web is achieved. Furthermore is achieved the advantage that different weights of the two juxtaposed bag items will not draw the web askew. By using a channel at the central support region it becomes possible to fill the two juxtaposed bags with different weight. They can also be filled at different times. The requirements for positioning of filling funnels and similar filling equipment will therefore be more flexible than in a situation where simultaneous filling of two juxtaposed bags has to be performed.

The guide means can thus be designed according to the above described prior art techniques as well as the peripheral areas of the bag items can be designed according to the prior art techniques. There is only need for modifying the filling station in a way so that it e.g. has two filling units that fill the two juxtaposed bag items simultaneously.

Carrier chains or similar in the guide means can therefore be moved through a course wherein in the filling station they will draw the two outermost bag edges apart in such a way that the two juxtaposed bag items are caused to open in order to enable filling of products into the two bag items from above or possibly from the side. The bag edges can then be guided together again for the purpose of final closing and cutting off of the filled bag items. At the end of the filling station, the guide means will typically be drawn apart such that the cut off bags can be gripped and moved away, or just fall down upon a conveyor belt.

It is not important how accurately the conveying is effected, whether a certain tension arises on the bag web during conveying if carrier chains provided with studs are used, as the bag web will be conveyed in full synchronisation with the carrier chains in a secure way.

According to an embodiment, the method may be peculiar in that the peripheral areas at the outermost opposite bag opening edges of two juxtaposed bag items are joined by welding or welded together with the central support region. Hereby is achieved an improved guiding of the outermost bag opening edges.

According to a further embodiment, the method may be peculiar in that the peripheral areas at the outermost opposite bag opening edges of two juxtaposed bag items are free peripheral areas. This simplifies the bag making itself, though the free peripheral areas put greater demands on guidance during conveying of the bag web through the apparatus. According to an embodiment, the apparatus may be peculiar in that the support rail includes an endless band, belt or similar for supporting the bag web. The bands or belts may thereby contribute to the conveying of the bag web. However, usually it is preferred to use a smooth guide rail on which the bag web slides. According to a further embodiment, the apparatus may be peculiar in that the filling station includes a first and a second filling unit, or alternatively includes a displaceable filling unit for filling the two juxtaposed bag items. The choice of filling unit depends on whether it is the same articles that are filled into both bags, or alternatively whether the advantage achieved by the invention by the option of filling different articles into two bag items conveyed in parallel is utilised.

According to a further embodiment, the apparatus may be peculiar in that the guide means include conveyor chains with projecting parts projecting freely from the conveyor chains and which can engage perforations or holes in respective peripheral areas, a guide channel that can engage a bead in respective peripheral areas, guide rails that can engage a channel in respective peripheral areas, or squeezed chains or belts that can engage respective peripheral areas by friction. As mentioned, by the invention the options known from the prior art described in the introduction can be applied.

According to an embodiment, the bag web may be peculiar in that the peripheral areas at the outermost opposite bag opening edges of two juxtaposed bag items are joined by welding or welded together with the central support region. Hereby is achieved a better guiding of the outermost peripheral areas by conveying through the apparatus.

According to a further embodiment, the bag web may be peculiar in that the peripheral areas at the outermost opposite bag opening edges of two juxtaposed bag items are free peripheral areas. This simplifies the bag production.

According to a further embodiment, the bag web may be peculiar in that the bag web is formed of a film web which is folded about folding lines in longitudinal direction of the bag web, the folding lines disposed with a spacing largely corresponding to one fourth of the width of the film web from each side edge of the film web for forming the two juxtaposed bag items. The two juxtaposed bag items can thus advantageously be made from one film web without any need of combining several film webs.

According to a further embodiment, the bag web may be peculiar in that the peripheral areas of the bag web at the outermost opposite bag opening edges of two juxtaposed bag items are each provided with a series of perforations for the guide means in an apparatus according to the invention. Secure and firm gripping of the peripheral areas is hereby achieved. According to a further embodiment, the bag web may be peculiar in that the peripheral areas of the bag web at the outermost opposite bag opening edges of two juxtaposed bag items are each provided with a longitudinal bead for engaging the guide means in an apparatus according to the invention. The guide means will include a channel or a chain which by friction can grip around the bead.

According to a further embodiment, the bag web may be peculiar in that the peripheral areas of the bag web at the outermost opposite bag opening edges of two juxtaposed bag items are each provided with a longitudinal channel for engaging the guide means in an apparatus according to the invention. The guide means will include guide rails that can be received in the channels and thereby provide secure guiding of the peripheral areas.

When performing the invention, the constructional details of bag web and apparatus known from the two European patents EP 1 087 890 and EP 1 451 069 can therefore be applied. Thus no detailed explanation thereof is given.

Also, only bag webs with two juxtaposed bags have been mentioned. However, within the scope of the invention it will be possible to increase the number of juxtaposed bags such that even three or four bags are juxtaposed in transverse direction and moved through a filling apparatus.

Description of the Drawing

In the following, the invention will be explained in more detail with reference to the enclosed schematic drawing where the channel essential for the invention in the central support region is only seen in Figs. 8-9, and wherein

Fig. 1 shows a perspective view for illustrating a technique known from EP

1 087 890 with a bag web including a single row of bag items;

Fig. 2 shows a perspective partial view of a bag web with two rows of juxtaposed bag items in partly open condition in a bag web according to the invention;

Fig. 3 shows a partial view from above of the bag web shown in Fig. 2, but with the bag items in fully open condition;

Figs. 4A-4F show six different possible bag webs according to the invention; Figs. 5A-5C show sectional views for illustrating three steps of inserting a bag web shown in Fig. 4A into a filling apparatus;

Fig. 5D shows a perspective partial view of a bag web in the first step shown in Fig. 5A;

Figs. 6A-6C show sectional views for illustrating three steps of inserting a bag web shown in Figs. 4B-4F into a filling apparatus;

Fig. 6D shows a perspective partial view of a bag web in the first step shown in Fig. 6A, with one welding;

Fig. 6E shows a perspective partial view of a bag web in the first step shown in Fig. 6A, with two weldings;

Figs. 7A-7D show sectional views for illustrating four alternative guide means in an apparatus according to the invention;

Figs. 8A-8B show two further possible bag webs according to the invention; and Figs. 9A-9C show sectional views for illustrating three steps of inserting a bag web shown in Figs. 8A and 8B into a filling apparatus.

Detailed Description of Embodiments of the Invention

In the explanation of the Figures, identical or corresponding elements will be provided with the same designations in different Figures. Therefore, no explanation of all details will be given in connection with each single Figure/embodiment.

Fig. 1 shows prior art and serves to illustrate a principle for designing peripheral areas at the outermost opposite bag opening edges and guide means adapted to retain and guide the peripheral areas at the opposing bag opening edges. In Fig. 1 is shown that from a supply roll 2 a film material web 4 can be unrolled, consisting of a double film folded around a bottom edge 6 and joined along the upper edge by a simple welding 8, without any foldings or thickenings of any kind. Therefore, it may also be a tubular film. In the web appears a series of slits 10 that extend from the bottom edge 6 up to a point below the upper edge 8 so that the web appears with mutually separate bag items 12, the side edges of which closed by weldings 14. Right over the top of the slits 10, the double web is cut by respective horizontal lines 16 extending shortly out at either side of the associated slits 10. Between the upper edge 8 and the cutting lines 16, the peripheral areas 40 of the web are penetrated by a single row of perforations 18.

This previously made web 4, which instead of being rolled up better can appear in a supply box in zigzag folded shape, is unwound by a filling unit on a support bar or rail 20 extending from a fixed support member 22 of the unit and serving as simple support for the closed upper edge 8 of the web 4.

At a short distance in front of the carrier member 22, the support bar 20 has an upwardly projecting cutter member 24 which by advancing the web will continuously cut the upper edge of the latter, and thereafter is arranged a continuing carrier system consisting of opposing parallel chain runs 26 that are made with upright holding studs 28 for engaging holes 18 in respective top parts of the web that are laid out at both sides, and by a pressing roller 30 which after threading the film web in provides for drawing down the said unfolded upper edge areas of the web 4 towards the firmly supported carrier chains 26 for horizontal bearing against the top sides of the latter, and thereby under pivoting down of the holes 18 in such a way that the holes 18 are pivoted down and engage over the chain studs 18. The pressing roller 30 has turned-in grooves 32 for enabling free passage of the outer end parts of the chain studs 28, and in these grooves there are embedded transversely positioned studs (not shown) which like a cogwheel can interact with the chain studs 28 for automatic synchronous driving of the pressing roller 30.

The opposing upper edge parts of the web 4 will then be securely anchored to the carrier studs 28, and the carrier chains may then be guided through a desired course for successive opening of the bag items as indicated by 34, whereby they can be filled by a filling apparatus 36 disposed above the open bag item and for closing the items after filling thereof. The filling apparatus 36 is provided with a filling unit in the form of a filling nozzle 38. It is considered unnecessary to indicate this in more detail. However, it is to be noted that the studs 28 are provided in the neutral lines of the chains such that the bag item web is not subjected to tensioning or slacking in passages with changes of direction. The filled bags are released from the rest of the web, which is rolled up as excess, by weld closing of the bag items immediately under the top of the slits 10 and possible subsequent cutting off. It is to be mentioned that on the fixed carrier member 22 there is preferably provided a guide body with a double-wing ploughshare shape that actively produces or initiates the shown unfolding of the perforated web periphery areas, whereby an improved security can be achieved with regard to the important function that is the guiding of the holes down over the studs 28.

Fig. 2 shows an apparatus according to the invention, wherein a bag web with two juxtaposed bag items 12 is used. At the outermost peripheral areas 40, the bag items 12 are penetrated by perforations 18 that enable fastening to the retainer studs 28. At the bag sides which are disposed close to each other, the peripheral areas of the bag sides are formed of a central support region 42 extending longitudinally of the bag web. The central support region 42 is placed on the support rail 20. According to the invention, the support rail 20 is extended compared with the length shown in Fig. 1. The support rail 20 will therefore extend along the conveyor path through a filling station 44 where the filling apparatus 36 is provided. The filling apparatus 36 has two juxtaposed filling nozzles 38 for simultaneous filling of the two juxtaposed bag items 12.

In a situation before the partial view shown in Fig. 2, the film web can be handled by a system as described with reference to Fig. 1. In a situation after the partial view shown in Fig. 2, the bag web can be closed and cut off in a way analogous to that explained in connection with the bag web shown in Fig. 1.

Fig. 3 shows a view corresponding to the view shown in Fig. 2, but seen from above. It is seen here how the bag items 12 are moved farther away from each other such that they now are completely open. In this situation, the bag items 12 will be located at the filling station 44 (not depicted in Fig. 3 for the sake of clarity).

The bag items 12 have side edges that are closed by means of welds 14. Figs. 4A-4F show various possible foldings of bag webs according to the invention. The provision of a central support region 42 serves to connect two juxtaposed bag items 12. The central support region 42 also serves to provide support on the support rail 20 when inserting the bag webs into an apparatus according to the invention.

In Fig. 4A is seen that the two outermost opposite peripheral areas 40 are provided as free edge areas that are not attached to each other or to the support region 42.

Fig. 4B shows a situation where the peripheral areas 40 are fastened to the central support region 42 by means of welds 46.

Fig. 4C shows how the two opposing peripheral areas 40 are welded together by one welding 48. This single welding 48 can optionally be made with or without connection to the central support region 42.

Fig. 4D shows how the two weldings 46 are provided as individual weldings.

Fig. 4E shows an alternative where only one welding 46' is provided, which simultaneously welds the two outermost opposite peripheral parts 40 to the central support region 42.

Fig. 4F illustrates how a welding 48 is used for welding the free peripheral regions 40 together without connection to the central support region 42.

Figs. 5A-5C show how a bag web is moved and opened when inserted in a packing apparatus. Fig. 5A shows the two bag webs without opening them and resting on the support during their advancing for engagement with the guide means.

Fig. 5B shows the situation where the bag web is brought to engage the guide means in the form of the studs 28 engaging perforations on the outermost opposite peripheral areas 40.

Fig. 5C shows how the guide means has moved the outermost opposite bag opening edges from each other such that the bag items 12 are open for filling. Fig. 5D shows a perspective view corresponding to Fig. 5A for illustrating how the bag web with the two juxtaposed bag items 12 is suspended and resting on the support rail 20 via the central support region 42.

Figs. 6A-6E are figures that correspond to Figs. 5A-5D. The differences are that the outermost opposite peripheral areas are not free, but welded together in a way as explained with reference to Figs. 4B-4F. By this design, the weldings 46 and 18, respectively, will provide guide channels 50 in which supplementary guide rails 52 are disposed extending in parallel with the guide rail 20. This provides good guidance when conveying the bag web to the filling apparatus. A cutting up is effected at the filling apparatus as explained in connection with Fig. 1 such that the channels 50 are opened, whereby the outermost peripheral areas 40 can engage the guide means in the form of the studs 28.

Figs. 7A-7D show alternative embodiments of the guide means.

Fig. 7A shows a design where the outer peripheral areas 40 are provided with a bead 54 guided in a channel 56, which is provided fixed on the filling apparatus and serves to retain and guide the peripheral areas at the outermost opposite bag opening edges through the filling station.

Fig. 7B illustrates that the outer peripheral areas 40 are provided with a channel 58. The channel 58 retains and guides the peripheral areas 40 along the conveyor path through the filling station.

Fig. 7C shows how the outer peripheral areas 40 are brought to engage gripping chains 62. The gripping chains 62 can retain and guide the peripheral areas by squeezing action along the conveyor path through the filling station. These guide means 64 can e.g. include cords or the like that may retain and guide the peripheral areas 40.

Figs. 8A-8B show two further foldings of bag webs according to the invention. In the central support region 42 connecting the two juxtaposed bag items 12, there is here provided a closed channel 65 serving as support on the support rail 20 at the insertion of the bag webs in an apparatus according to the invention. In Fig. 8A is seen that the closed channel 65 is formed by welding a separate film strip 66, which by two weldings 67 is welded on the film web 4 that is used for making the bag items 12.

Fig. 8B shows an embodiment where the closed channel 65 is formed. The film web 4 is provided with a fold 68 forming the channel 65, which is closed by a welding 69.

Figs. 8A and 8B show closed channels as the welds 67 and 69 are through-going welds running throughout the length of the film web 4. However, alternatively spot weldings may be applied such that the channel appears as a closed channel. Figs. 9A-9C are figures that correspond to Figs. 6A-6D. The difference in this embodiment is that the central support region 42, which is placed on the support rail 20, in this situation is formed as a closed channel 65. The risk of the film web being drawn askew by uneven filling of two juxtaposed bags 12 is hereby avoided. The guide rail mentioned by the various embodiments may consist of a smooth rail on which the central support region slides. The guide rail may alternatively comprise belts, chains or similar provided with an endless run in such a way as to contribute to conveying the bag web along the conveyor path into and through the filling station.