WO1994022720A1

WO1994022720A1 - Packaging arrangement

Info

Publication number: WO1994022720A1
Application number: PCT/SE1994/000302
Authority: WO
Inventors: Timo Järvinen
Original assignee: Amerplast Ab
Priority date: 1993-04-07
Filing date: 1994-04-06
Publication date: 1994-10-13
Also published as: SE501137C2; SE9301174D0; SE9301174L; AU6440794A

Abstract

Arrangement for packing products, in particular loaves of bread, into plastic bags which are fed in the form of a continuous strip of plastic bags (15) with the help of a driving means (20) which advances the bags from a container (19) as far as the discharge track for the loaves. The driving means comprises an upper and a lower endless feed belt (21; 22) so arranged as to run along an upper and a lower bag-opening track (25; 26) and, by exerting a clamping effect, as to feed and guide an upper and a lower mouth flap on the bags. The aforementioned tracks (25; 26) are so arranged in a first part (32) as to diverge in order to move the flaps (17; 18) apart and provide sufficient space for an inserting device to introduce a product into the respective bag essentially at right-angles to the direction of feed of the bags. The tracks are so arranged in a second part (33) as to converge in order to bring the flaps together so that the bags can be closed. In order to improve the engagement with the flaps and to reduce the friction with the bag-opening tracks, an interjacent endless support belt is so arranged as to run around the respective track (25; 26) and to accompany it along the side facing towards the endless feed belt. In this way the support belts and the feed belts are in contact with one another and produce the aforementioned clamping effect against the bag flaps.

Description

Packaging arrangement

The present invention relates to an arrangement for packing products, in particular loaves of bread, into plastic bags which are fed in the form of a continuous strip of plastic bags, comprising- an upper and a lower endless feed belt so arranged as to run along an upper and a lower bag- opening track and, by exerting a clamping effect, to feed and guide an upper and a lower mouth flap on the bags, in conjunction with which said tracks are so arranged in a first part as to diverge for the purpose of moving the flaps apart and provide sufficient space for an inserting device to introduce a product into the respective bag essentially at right-angles to the direction of feed of the bags, and in conjunction with which the tracks are so arranged in a second part as to converge for the purpose of bringing the flaps together so that the bags can be closed.

An arrangement of the above kind has been produced in order to increase the reliability and the capacity of plants for the mechanical packing of bread into plastic bags, in particular with regard to sliced loaves and tin loaves. Unlike customarily used packaging machines, this previously disclosed arrangement operates in accordance with the principle that the bags are fed and opened mechanically on a track running parallel with the feed track for the loaves. An inserting device or pusher introduces the loaves into the open bags in turn in the longitudinal sense, whereas feeding takes place in the transverse sense. This previously disclosed arrangement represents radical and innovative thinking in relation to the systems which are normally used today, according to which the loaves are introduced into the plastic bags at the end of the feed track. In accordance with such a system, the loaves are transported in the longitudinal sense and are guided into opened bags suspended from hoops. In an alternative embodiment, a web of film is welded together to form bags over the loaves, which are then normally fed in the transverse sense.

The arrangement referred to by way of introduction thus comprises two endless feed belts which are in contact with an upper and a lower bag- opening track. A film strip of continuous bags is so arranged as to be caused to advance by the feed belts through a clamping effect on an upper and a lower mouth flap on the bags. The bag-opening tracks are so arranged as to separate the flaps, in conjunction with which the upper flap and the lower flap will run respectively along the upper and the lower track, so that the bags are opened and the loaves can be introduced. This underlying principle has proved to be advantageous from several points of view in pilot plants, in particular with regard to the rate of packing and the gentle handling of the bread. However, no plant has yet been manufactured which has functioned satisfactorily in everyday continuous operation, since the bag feeding system has become excessively hot in the course of lengthy operating periods, eventually causing the plastic film to begin to become deformed by the heat. In an attempt to remedy this, trials have been carried out with various materials in order to reduce the friction between the plastic film and the bag-opening tracks, although no suitable solution for continuous operation has yet been found.

One object of the present invention is accordingly to make available a packaging arrangement of the kind referred to by way of introduction with the improvement that it is capable of working without the risk of overheating for the operating periods normally required in bakeries and other automatic packing plants. Another object is to create an arrangement which is capable of holding the bags as they are being fed with a more reliable and more secure grip than the previously disclosed arrangement. Further objects and improvements can be appreciated from the following description. They are achieved through the characteristics indicated in the following Patent Claims.

The basis for the invention is the knowledge that the sliding friction between the strip of plastic bags and the fixed bag-opening tracks must be avoided in order to permit the use of bags made of normally encountered materials. This has been achieved by providing the aforementioned tracks with endless support belts so arranged as to form an underlayer for the mouth parts of the bags and to accompany the feed belts in their movement. Unlike the plastic bags, the support belts can be selected freely with regard to both their material and their composition in order to obtain the lowest possible sliding friction against the fixed underlayer, but at the same time to provide a secure grip on the plastic film. In a further development of the invention, provision is made for the strip of bags to be caused to advance by the feed belts through a clamping effect between the upper and lower belt over a certain distance before and after the bag-opening tracks. The contact pressure on the plastic film can be reduced in this way as it passes over the bag-opening tracks, whereas higher pressure can be applied to the film in other sections where the driving feed belts are in contact with one another. The feed belts and the support belts should preferably be driven at the same speed, so that the film does not run the risk of becoming creased and can be held in a fixed grip. This can be achieved purely through the effect of friction between the motor-driven feed belts and the support belts, although it is more advantageous also to arrange for the support belts to be driven via some appropriate form of mechanical coupling with the feed belts or their motor unit. Most advantageous of all, however, is to provide the support belts with a separate drive motor. The invention is now described in more detail with reference to the accompanying drawings, in which:

Fig. 1 is a plan view of an arrangement in accordance with the invention; Fig. 2 is a cross-section through the bag-feeding arrangement in accordance with the line 2-2 in Fig. 1; Fig. 3 is a perspective view of a strip of plastic bags suitable for use together with the arrangement in accordance with the invention; Fig. 4 is a detailed section through the front part of the bag-opening tracks; Fig. 5 is a corresponding detailed section at the end of the bag-opening tracks; and Fig. 6 is a cross-section through the bag-opening tracks in accordance with the line 6-6 in Fig. 2.

The illustrated arrangement is intended for packing bread, in particular sliced tin loaves, into plastic bags in large bakeries. The arrangement comprises a feed track 11 for the sliced loaves 12 and, running in parallel with it, a discharge track 13 for the loaves packed into bags 14. The bags are initially joined together in continuous form as a strip of plastic bags 15 of the kind illustrated in Fig. 3, which shows the presence of a perforated tearing notch 16 between the bags and also that these have an upper and a lower mouth flap 17, 18. The strip of plastic bags 15 is introduced into the machine with the help of a driving means

20, which advances the bags from a container 19 as far as the discharge track 13 for the loaves. The driving means 20 comprises an upper and a lower feed belt 21, 22 arranged as two endless loops in a vertical plane situated between the two feed tracks 11, 13. Positioned centrally between the mirror-inverted loops is a tapered distributor frame 23 so arranged as to open the bags and as to create a free space 24 for the passage of the loaves at right-angles through the loops.

The distributor frame 23 is entirely symmetrical in relation to the horizontal plane and exhibits an upper and a lower bag-opening track 25, 26 and a front tapered element 27. The bag-opening tracks 25, 26 are formed from bent plastic rails 28, which have been provided with surface inserts 29 of metal for reducing the friction. The rail is bent into a first higher curved part 30 and a second lower curved part 31, in conjunction with which the first half of the higher part 30 represents a diverging part 32 of the distributor frame 23 and the other parts represent a more or less tapering or convergent part 33. The feed belts

21, 22 are so arranged, through a clamping effect against one another or against the bag-opening tracks 25, 26, as to cause the strip of plastic bags 15 to advance towards the discharge track 13. This clamping engagement does not take place across the entire width of the bags, but only at the mouth flaps 17, 18 of the bags. A number of pairs of wheels 34, 35 is so arranged as to force the feed belts against one another and to guide them along the bag-opening tracks 25, 26, and additional guide wheels 36 lead the belts around an outer loop. One of the pairs of wheels 35 is connected to a driving means (not shown here) for propelling the belts.

In order to avoid friction and to improve the engagement with the plastic film, the feed belts 21, 22 are not in direct contact with the plastic rails 28, but rather with two support belts 37, 38 arranged as endless loops around either bag-opening track 25, 26. On the side of the tracks facing towards the feed belts, the support belts run along the metal inserts 29 in a guide groove formed between raised edge parts 39 of the plastic rail, and on the other side of the rail in a cavity 40 between it and an inner cover plate 41, 42. The respective cover plate and rail are in turn mounted on an upper and lower bracket 43, 44, which is attached by some appropriate means to the frame of the drive unit 20. The cover plates 41, 42 restrict the free space 2-4 together with two connecting plates 45, 46 at the ends of the tracks. The support belts 37, 38 run around front and rear end wheels 47, 48 and 49, 50 and around tensioner devices 51, 52. The support belts 37, 38 may be so arranged as to run freely around the respective loop, or may be separately driven with the help of a driving means (not shown here). Steps should preferably be taken to ensure that the support belts and the feed belts are driven at exactly the same speed, so that the bag flaps can be maintained in a stable position between the belts.

Situated at the end of the feed track for the loaves 11 is an inserting device 53 or pusher so arranged with the help of one or more carriers 54 as to cause the loaves to advance through the free space 24 and into the opened bags 14. The carrier 54 is so arranged for this purpose as to accompany the loaf for a certain distance, so that it is held securely in the bag whilst it is fed forwards and until it can be closed once again. The strip of plastic bags 15 is caused to advance over an initial distance 55 through direct contact between the feed belts 21, 22. The mouth flaps 17, 18 are then separated with the help of the tapered element 27 and are led along the upper and lower bag-opening track 25, 26 respectively. The bags require to be separated from one another by tearing before they reach this position; this is done with the help of a moving knife 56, which separates the bags at the perforation 16. Once the loaf has been introduced into the bag, the pack is supported by the discharge track 13 and is advanced synchronously with the feed belts 21, 22. In the second curved part 31 of the distributor frame, the carrier 54 is withdrawn and the mouth flaps 17, 18 are forced together again between the feed belts 21, 22 on a final contact section 57. Here the bags are also separated from one another completely and are sealed in an appropriate fashion.

The support belts are preferably made from a woven plastic material such that the woven structure provides a firm grip on the plastic film, although the material itself should exhibit easy-running properties, so that the belt can slide easily against the metal rail 29 and inside the cavity 40 on its return path. A woven polyamide belt has been found to function excellently, even during long-term continuous operation. Both the support belts, feed belts and bag-opening tracks can be varied in many ways within the scope of the following Patent Claims in terms of both their design and the choice of materials.

Claims

Patent Claims

1. Arrangement for packing products, in particular loaves of bread, into plastic bags which are fed in the form of a continuous strip of plastic bags, comprising an upper and a lower endless feed belt (21;22) so arranged as to run along an upper and a lower bag- opening track (25;26) and, by exerting a clamping effect, as to feed and guide an upper and a lower mouth flap (17;18) on the bags, in conjunction with which said tracks (25;26) are so arranged in a first part (32) as to diverge so as to move the flaps (17;18) apart and provide sufficient space for an inserting device (53) to introduce a product (12) into the respective bag essentially at right-angles to the direction of feed of the bags, and in conjunction with which the tracks are so arranged in a second part (33) as to converge so as to bring the flaps (17;18) together so that the bags can be closed, characterized in that an interjacent endless support belt (37;38) is so arranged as to run around the respective track (25;26) and to accompany it along the side facing towards the endless feed belt, so that the support belts (37;38) and the feed belts (21;22) are in contact with one another and produce the aforementioned clamping effect against the bag flaps.

2. Arrangement in accordance with Patent Claim 1, characterized in that the feed belts (21;22) and the support belts (37;38) are so arranged as to run at the same speed along the bag-opening tracks.

3. Arrangement in accordance with Patent Claims 1 or 2, characterized in that a driving means is so arranged as to drive the support belts (37;38) around the respective track.

4. Arrangement in accordance with one or other of the preceding Patent Claims, characterized in that the feed belts (21;22) are so arranged as to be in contact with one another for a certain distance (55;57) before and/or after the bag-opening tracks.

5. Arrangement in accordance with one or other of the preceding Patent Claims, characterized in that each bag-opening track (25;26) comprises a rail (28) with a frame of a plastic material and a surface insert (29) of metal so arranged as to make contact with the respective support belt (37;38) with low friction.

6. Arrangement in accordance with Patent Claim 5, characterized in that large parts of the inner side of the rail facing towards the other track are covered by a cover plate (41;42) forming a cavity (40) between the rail and the plate, in which cavity the support tracks (37;38) run freely along the periphery of the rail.

7. Arrangement in accordance with one or other of the preceding Patent Claims, characterized in that the bag-opening tracks (25;26) are mirror-inverted in relation to one another and are identical in form, and in that the first divergent part (32) creates a free space (24) between the tracks to permit the passage of the products from a product inlet (11) on one side of the plane of the feed belts to the other side (13), where the strip of plastic bags (15) runs in parallel with the feed belts (21;22) and is able to accept the products.

8. Arrangement in accordance with Patent Claim 7, characterized in that the bag-opening tracks (37;38) exhibit a first higher curved part (30) and a second lower curved part (31), in conjunction with which the passage of products is so arranged as to take place between the higher curved parts (30).

9. Arrangement in accordance with one or other of the preceding Patent Claims, characterized in that the rail (28) exhibits raised edge parts (39) for guiding the support belt, and in that end wheels (47,49;48,50) are arranged at the ends of the tracks (25;26), around which wheels the support belts (37;38) are so arranged as to run on their way around the tracks.

10. Arrangement in accordance with one or other of the preceding Patent Claims, characterized in that the support belts (37;38) are made of a woven plastic material, preferably polyamide.