US3866395A

US3866395A - Apparatus for closing a foil packing, in particular a foil bag

Info

Publication number: US3866395A
Application number: US388911A
Authority: US
Inventors: Karl-Ernst Timmerbeil
Original assignee: Packautomatic & Co KG GmbH
Current assignee: Packautomatic & Co KG Firma GmbH; Packautomatic & Co KG GmbH
Priority date: 1972-08-19
Filing date: 1973-08-16
Publication date: 1975-02-18
Anticipated expiration: 1992-02-18
Also published as: DE2240909B2; DE2240909C3; DE2240909A1; IT992825B

Abstract

An apparatus for the heat-sealing of a film package, particularly a film bag, containing an article to be packed, which comprises a film-pulling device and a heat-sealing device defining a heat-sealing plane. A pair of pulling rollers is disposed adjacent the heat-sealing device on both sides of the heat-sealing plane. A device is provided for rotation of the pulling rollers and the latter are arranged for movement towards one and other.

Description

United States Patent Timmerbeil 1 Feb. 18, 1975 [5 1 APPARATUS FOR CLOSING A FOIL 3,200.560 8/1965 Randall 53/112 8 x CKI IN PARTICULAR A FOIL BAG 3.289.387 12/1966 Stagmeier et a1. 53/112 B 3.377.772 4/1968 53/372 x [75] In nt r: Kar -E ns Tlmmerbell, Ennepetal. 3,461.645 8/1969 Synder 53/373 x Germany 3.471.991) 10/1969 Bonuchi et a1 53/372 X 3 731 Assignee: Firma Packautomatic GmbH & C0. Wm 53/37 X Ennepetal Germany Primary E.\11miner-'l'ravis S. McGehee [22] Filed: Aug. 16, 1973 Assistant lzxaminerHorace M. Culver Attorney, Agent. or FirmErnest G. Montague; Karl [21] Appl' 388311 F. Ross; Herbert Dubno [30] Foreign Application Priority Data [57] ABSTRACT Aug. 19. 1972 Germany 2240909 An apparatus for the heat-sealing of a film package, particularly a film bag, containing an article to be [52] US. Cl. 53/373 packed, which comprises a film-pulling device and a [51] Int. Cl..... B65b 7/06, B65b 13/22, B65b 51/14 heat-sealing device defining a heat-sealing plane. A [58] Field of Search 53/372, 373, 124 A, 124 B, pair of pulling rollers is disposed adjacent the heat- 53/24, 39, 40 sealing device on both sides of the heat-sealing plane. A device is provided for rotation of the pulling rollers [56] References Cited and the latter are arranged for movement towards one UNITED STATES PATENTS and Other- 2,877,615 3/1959 Foster 53/112 B X 6 Claims, 9 Drawing Figures PATEHTED FEB l 8 I975 SHEET 1 BF 3 APPARATUS FOR CLOSING A FOIL PACKING, IN PARTICULAR A FOIL BAG package wrapping produced from? film irfwhiclfall sides of the package, except a single end side, are already closed to form a film bag which then is closed completely.

For this purpose prior-art devices include a heatsealing device and, behind this device, clamping and pulling jaws which are relatively movable vertically so as to grip the overhanging film and then pull it horizontally into an adjacent position by a horizontal movement, thereby tightening the film against the material to be packed, whereupon the heat-sealing takes place. Devices of this type, have the disadvantage that, because their parts move in two planes, they are rather expensive to manufacture also it is not possible with these prior devices to obtain close and dependably tight packings around the goods. For this reason, it frequently happens in practice that workers stand at the heat-sealing device in order to pull the protruding parts of the film by hand away from the goods and then tightly around the same so as to ensure tight packaging.

It is therefore another object of the present invention to provide a device of simple construction by means of which film-bag package, which tightly hug the material to be packed can be obtained in an economical and dependable manner.

According to a feature of the present invention l provide in the vicinity of the heat-sealing device a pair of pulling rollers, the pulling rolls of which are driven and are arranged on opposite sides of the heat-sealing plane, the rollers being movable with respect to each other. The pair of pulling rollers provided in accordance with the present invention can now grip the protruding parts of the film bags and pull them along the article being packed which is held back (retained), for instance, by the pulling rolls themselves or other retaining means. In this way the tight package is always obtained, and even articles to be packed which are of different height or of different depth can be packed equally dependably and well.

Because a driven pair of pulling rollers is used in the system of the present invention, only movement in a single plane is necessary for their action and the drawing ofthe film. As a result, a considerable simplification in construction is obtained, by comparing with a device having clamping and pulling jaws which are movable in two planes at right angles to each other.

When the heat-sealing device is formed of two heatsealing jaws which are movable towards each other, one pulling roller is arranged on the one heat-sealing jaw and is movable together with it, while the other pulling roller is arranged for movement by means of a swinging device which is'provided on the fixed stand of the heat-sealing apparatus.

This arrangement of the pulling rollers is advantageous because the first pulling roller is movable directly with a heat-sealing jaw and thus does not require any drive of its own, while the other pulling roller is movable independently of the second heat-sealing jaw by a separate swinging device. Preferably, the unheated heat-sealing jaw is provided with the pulling roller which is movable with it, while the separately swingable pulling roller is disposed adjacent the heated heatsealing jaw. The latter arrangement has the advantage, that the pulling rollers can come into engagement and into active positions before the film is heated by the heat-sealing jaw and, as before premature heat sealing. Despite the simplicity of design and low cost coupling one of the two pulling rollers with one of the two heatsealing jaws, the present invention provides a control of the pulling rollers which is independent of the movement of the heat-sealing jaws.

In accordance with another proposal of the present invention, the second pulling roller, which is not connected with the heat-sealing jaw can also be fixed in space within the region of the heat-sealing plane. This is advantageous, when flat bags are to be closed, rather than high film bags or film bags of different height. ln the case of small, flat bags, the protruding film lies approximately in the heat-sealing plane, so that it is sufficient for it to be grasped by the pulling roller, which is movable with the first heat-sealing jaw and pressed against the fixedly positioned second roller. Thus no operating mechanism is required for the control movement of the pulling roller.

Depending on the nature of the goods to be packed and depending on whether the bags produced are thin envelope-like containers or thick cushion like packings, the pulling rollers can be arranged either between the material to be packed and the heat-sealing jaws, or else along the side of the heat-sealing jaws facing away from the material to be packed.

When the pulling rollers are arranged between the packaged article and the heat-sealing jaws there is the substantial advantage that only an extremely slight projection of film is necessary in order for the film to be gripped by the pulling rollers, and the amount of film required and the waste can therefore be reduced. When the pulling rollers are arranged behind the material being packed and behind the heat-sealing device, there is the advantage that extremely tight package can be produced, since the heat-sealing takes place directly on the article being packed. The material being packed can, in this case, advantageously rest against the heatsealing jaws while the film is being pulled tight along it on all sides.

It is also advantageous, in accordance with the present invention, for the drive of the first pulling roller to be an electric motor and for this motor to drive the other pull roller in the cooperating position of the pair of pulling rollers by means of gears, at least one gear being provided on one side of each pulling roller.

Thus the two pulling rollers are driven synchronously when they rest against each other and pull the film tight, while only a single drive unit is necessary for this purpose.

If the horizontal side surfaces of the sheet of packing film are already completely folded during the folding and packaging process which has preceded the last heat-sealing, then it is advisable to provide a guide ledge which extends in the direction of the folded side surfaces of the film packing and rests tightly against the material being packed. This guide ledge provides assurance on the one hand, that the folded side surfaces of the packing will remain folded and will not get in the way of the final heat-sealing process; the guide ledge also provides an abutment for the material being packed as support against the pull of the film and thereby permits a deep bagging of the material being packed.

If, in accordance with a further feature of the present invention, the surface of the lower pulling roller has a higher coefficient of friction than the surface of the upper pulling roller does it being assumed that the heat-sealing takes place in a horizontal plane this offers the advantage, that even heavy materials can be packed dependably and with uniform tightness. The stronger pulling force on the lower sheet of film as compared with the weaker pulling force on the upper sheet of film which is necessary particularly when packing heavy articles in a film packing which rests snugly on all sides, is compensated for by the greater friction force of the film against the lower pulling roller.

The lower pulling roller can be provided with a rougher covering or other known friction-increasing means. For instance, the lower roller could be covered with soft Moltopren, while the upper roller is provided with a covering of PVC, which has a lower coefficient of friction than the Moltopren covering. A uniform pull is obtained since the upper pulling roller slides on the upper film when certain pulling forces are exceeded, while the lower pulling roller still entrains the lower film until a predetermined load has been reached.

The establishing of the predetermined load can be achieved by making the maximum torque of the motor driving the pulling rollers adjustable. In order to limit the torque, one can utilize overload switches or slip clutches or else select a suitable motor. By the limiting of the torque or pulling force, overstretching or tearing of the film is reliably prevented.

The present invention has thus succeeded in providing a device for the closing of a film package, particularly a film bag, which is capable of pushing material to be packed with adjustable force as deep as possible into a film sleeve. In addition, the present invention makes it possible for the film to be stretched as tightly as possible around the article being packed. And finally 'packages of different depth of contents can be closed while retaining the advantage of a tight, close packing.

It is immaterial in principle in this connection how the film bag which is finally to be closed has been produced in a previous packaging machine. The device can be used wherever it is desired to close a film bag which is already closed on three sides.

These and other objects will become more readily apparent from the following detailed description, reference being made to the accompanying drawing, in which:

FIG. 1 is a side-elevational view of a device in accordance with the present invention at the start of the closingprocess;

FIG. 2 an end view thereof;

FIG. 3 a top-plan view thereof;

FIGS. 4 to 6 are views corresponding to FIGS. 1-3, respectively at a more advanced stage of the closing process; and

FIGS. 7 to 9 are corresponding views in the final stage of the heat-sealing process.

It is immaterial how an article 10 to be packed has been brought into a film bag bya previous packaging device or how this film bag has been formed around the article to be packed. It is merely necessary that the article be already in a film bag which is closed on three sides and on the end side of which, which is still open,

the side surfaces have already been folded inwards by a folding device. The article which is thus partially wrapped is fed on a conveyor belt 1 to the heat-sealing and closing device. The heat-sealing device, in the embodiment shown, consists of two heat-sealing

jaws

2 and 3; which are movable towards each other, one of the heat-sealing jaws, the jaw 2, is heated. On the side of the heat-sealing

jaws

2 and 3 facing away from the article to be packed there are located pulling rollers 4 and 5, which together form a pair. The lower pulling roller 4 is fixed on the lower heat-sealing jaw 3 and movable together with it. The second pulling roller, the upper pulling roller 5, is driven by an electric motor 6 and transmits the drive movement in the adjoining condition of the pulling rollers 4 and 5 via gears 7 (FIGS. 1 and 4) arranged at least at one end of the pulling rollers. A guide ledge 8 arranged in the direction of the conveyor belt 1 secs to it that the fold of the side parts of the film remains intact. While the lower pulling roller 4 is firmly connected to the heat-sealing jaw 3, the second pulling roller 5 is arranged on a swivel device 9, which in its turn is rigidly connected with the stand of the heat-sealing device.

FIGS. 1 to 3 show a film bag fed on the conveyor belt 1 directly before its final heat-sealing. The parts of the film which protrude on one side extend between the heat-sealing jaws and between the pulling rollers. At this time, the lower heat-sealing jaw 3 and the pulling roller 4 coupled with it move up into their working position in the heat-sealing plane, and at the same time the upper pulling roller 5 swings downwardly in the direction of the heat-sealing plane. The pulling rollers 4 and 5 thereby come into mutual engagement and pull the film closely past by the article 10 which rests against the ledge 8, this continuing until the pulling force, which has been set, is reached. This is shown in FIGS. 4 to 6.

The upper, heated heat-sealing jaw 2 now enters into action, by moving in the direction towards the heatsealing plane and pressing against the unheated heatsealing jaw 3 which is already in its operating position. While the heat-sealing now takes place under the pressure of the heat-sealing

jaws

2 and 3, the pulling roller 5 can move back into its position of rest, as shown in FIGS. 7 to 9.

The pulling rollers 4 and 5 are provided with a covering, which has a sufficiently high coefficient of static friction with respect to the film to grip the film reliably and dependably. When packaging very heavy articles as in the present example the lower pulling roller 4 has a covering, which has a higher coefficient of friction than the covering of the upper pulling roller 5. Finally, it may also be pointed out that, depending on the nature of the heat-sealing device, the heat-sealing can take place as long as the pulling rollers are in engagement or else after they have moved again away from each other. The first method results in very tight packages, but makes it necessary to have a heat-sealing device, which very firmly clamps the film during the heat-sealing and takes up the film tension coming from the pulling rollers. Furthermore, the heat-sealing must cool down sufficiently before the clamp opens. Accordingly in most cases it is sufficient for the heat-sealing to take place after the pulling rollers have moved away from each other again.

Last but not least, it is self-evident, that the embodiment described and shown constitutes merely one example of the inventive concept and rather numerous other solutions are also possible. Thus, for instance, the pulling rollers could also be replaced by pulling rolls possibly a plurality of them arranged in a row. Instead of the gears for the coupling of the pulling rollers for rotation with respect to each other, a friction drive could be used in which the friction disks have contact with each other, when the pulling rollers contact each other.

I claim:

1. An apparatus for the tightening of a film package and the sealing of a side of the package enclosing an article on at least three sides and having a projecting flap on the side to be closed, said apparatus comprising:

a heat scaling device including a support,

a first heat sealing bar mounted on said support for movement perpendicular to the longitudinal dimension of said bar,

a further bar cooperating with said heat sealing bar to clamp said flap between said bars, and

means for heat sealing said flap upon the clamping thereof between said bars and consituted by heating means on at least one of said bars; and

a pulling device engageable with said flap for drawing the film of said package tightly around said article, said device including a first pulling roller mounted on said first bar for movement therewith,

a second pulling roller on said support copperating with said pulling roller to grip said flap between said rollers,

a swinging mechanism pivotally mounting said second roller on said support for movement toward and away from said first pulling roller,

an electric motor operatively connected to one of said pulling rollers for driving same, and

a respective gear on one side of each pulling roller and'connected thereto, said gears meshing upon swinging movement of said second pulling roller toward said first pulling roller.

2. The apparatus defined in claim 1 wherein both of said rollers are disposed to a side of said bars facing away from said article.

3. The apparatus defined in claim 2, further comprising a retaining ledge engageable with said package and overlain by said flap for retaining said package against entrainment upon rotation of said pulling rollers.

4. The apparatus defined in claim 3, further comprising a horizontal conveyor for transporting said package past said devices, said ledge running parallel to said conveyor.

5. The apparatus defined in claim 4 wherein one of said rollers has a film-engaging surface with a higher coefficient of friction than the film-engaging surface of the other roller.

6. The apparatus defined in claim 4, further comprising means for limiting the driving torque transmitted to

Claims

1. An apparatus for the tightening of a film package and the sealing of a side of the package enclosing an article on at least three sides and having a projecting flap on the side to be closed, said apparatus comprising: a heat sealing device including a support, a first heat sealing bar mounted on said support for movement perpendicular to the longitudinal dimension of said bar, a further bar cooperating with said heat sealing bar to clamp said flap between said bars, and means for heat sealing said flap upon the clamping thereof between said bars and consituted by heating means on at least one of said bars; and a pulling device engageable with said flap for drawing the film of said package tightly around said article, said device including a first pulling roller mounted on said first bar for movement therewith, a second pulling roller on said support copperating with said pulling roller to grip said flap between said rollers, a swinging mechanism pivotally mounting said second roller on said support for movement toward and away from said first pulling roller, an electric motor operatively connected to one of said pulling rollers for driving same, and a respective gear on one side of each pulling roller and connected thereto, said gears meshing upon swinging movement of said second pulling roller toward said first pulling roller.

6. The apparatus defined in claim 4, further comprising means for limiting the driving torque transmitted to said rollers.