Patent Application
20220371757
The invention relates to improvements of a vertical flow-wrapper, for producing tubular bags from a film web with re-closure means and the corresponding bag. The invention further relates to a method to produce a bag.
This application is a US National Stage entry of International Application No. PCT/EP2020/077172 filed on Sep. 29, 2020, which claims priority to EP 19200515.5 filed on Sep. 30, 2019 and to EP 20159691.3 filed on Feb. 27, 2020.
A common method of making bags out of a film web is the use of a vertical flow-wrapper, as for example disclosed in US 2018/033427 A1 or in DE 20 2018 104 342 U1. Such a packaging machine receives a continuous flat sheet, a film of plastic material, e.g. a thermoplastic material, which is transported continuously or intermittently and passed downwardly over a form shoulder and is then shaped into a tubular form, i.e. into a film/film tube, by being wrapped around a vertical form-fill tube of the packaging machine. After being wrapped around the vertical form-fill tube, the film web is longitudinally closed by means of a longitudinally extending seal which is applied to the film especially by heat sealing the lateral/longitudinal margins of the film web or by heat sealing in the vicinity of these margins thereby joining them. This is carried out by so called longitudinal-sealing means. The film tube has conventionally a rectangular, elliptical, circular or other shaped cross-sectional area. Conventionally, the film tube is closed by cross-sealing means, preferably in a direction perpendicular to the direction of flow, i.e. transversely. Thereby, individual bags are defined out of the continuous film tube. A product, such as a foodstuff, is introduced by dropping the product through a form-fill tube and into the film tube surrounding the form-fill-tube. During filling, the film tube is transversely open at its upper end, i.e. not cross-sealed. Thereafter and/or simultaneously, the film tube together with the product is moved downwardly and then a top cross-seal is formed above the product and thereby a hermetically closed bag produced. As a last step or simultaneously to the application of the top seal, the bag is separated from the film tube by cutting means. According to the present invention, the vertical flow wrapper comprises means to apply re-closure means to each package, arranged parallel to the longitudinal seal. With these re-closure means, the bag can be reclosed after it has been opened by removing and/or opening the longitudinal seal. The re-closure means are normally applied to the film prior to providing the longitudinal seal.
The purpose of the present invention is to improve the vertical flow-wrapper and/or the resulting bag.
The purpose is attained by providing a vertical flow-wrapper with:
The disclosure regarding this embodiment of the present invention also applies to the other embodiments of the present invention. Subject matters from one embodiment can be incorporated into other embodiments and vice versa.
The present invention relates to a vertical flow-wrapper with a frame and/or a housing. A continuous plane sheet, a film of plastic material, e.g. a thermoplastic material is transported continuously or intermittently and passed over a form shoulder and thereby shaped into a tubular form, i.e. into a film tube and then wrapped around a vertical form-fill tube of the packaging machine. After being wrapped around the vertical form-fill tube, the film web is longitudinally closed by means of a longitudinally extending seal which is applied to the film especially by sealing, preferably heat sealing, the lateral/longitudinal margins of the film web or by sealing in the vicinity of these margins thereby joining them. This is carried out by so called longitudinal-sealing means. The film tube has conventionally a rectangular, elliptical, circular or other shaped cross-sectional area. Conventionally, the film tube is closed by cross-sealing means, preferably in a direction perpendicular to the direction of flow, i.e. transversely. Thereby, individual bags are defined out of the continuous film tube. A product, such as a foodstuff, is introduced into the film tube by dropping the product through a form-fill tube and into the film tube surrounding the form-fill tube. During filling the film tube is transversely open at its upper end, i.e. not cross-sealed. Thereafter and/or simultaneously, the film tube together with its product is moved downwardly and then a top cross-seal is provided above the product and thereby the hermetically closed bag is completed. As a last step or simultaneously to the application of the top cross-seal, the bag is separated from the film tube by cutting means.
The longitudinal sealing means comprises a seal jaw which heats the film. A pair of guiding rollers are provided, relative to the transport direction of the film-tube, upstream from seal jaw to guide the two opposing ends of the formed film, which are sealed together, through the seal jaw. Pressing means to press the two opposing ends of the formed film together to form the longitudinal seal are provided, relative to the transport direction of the film-tube, downstream from the seal jaw.
The film passes though the pair of guiding rollers. One roller is preferably provided on each side of the film.
Preferably, one of the two rollers is driven, preferably with a motor. The roughness of the surface of the rollers, particularly the driven roller, is preferably such, that the roller(s) can slip relative to the film.
According to the present invention, the axis of rotation of the guiding rollers are provided parallel to the transportation plane of the two opposing ends of the formed film and not perpendicular to the transport direction.
Preferably, the angle under which the axis of rotation is provided is adjustable, preferably automatically. Preferably, the normal force applied to the film by the two rollers can be adjusted, preferably automatically.
According to another or a preferred embodiment of the present invention, the guiding rollers stretch the film in a transversal direction.
The disclosure regarding this embodiment of the present invention also applies to the other embodiments of the present invention. Subject matters from one embodiment can be incorporated into other embodiments and vice versa.
Preferably, the degree of stretching can be adjusted, preferably by changing the angle under which the axis of rotation of the guiding rollers are provided and/or by changing the normal force applied to the film by the two rollers.
Preferably, the pair or rollers that does the stretching comprises one cylindrical roller and one roller with a convex surface.
The following applies to all embodiments of the present invention.
According to a preferred embodiment of the present invention, the vertical flow wrapper comprises means to apply re-closure means to each package, arranged parallel to the longitudinal seal. With these re-closure means, the bag can be reclosed after it has been opened by removing and/or opening the longitudinal seal. The re-closure means are preferably applied to the film at least partially simultaneously to providing the longitudinal seal.
The re-closure means preferably comprise closing means, such as a male and a female part or such as tongue and groove which are preferably provided as two parts, respectively. Each part of the closing means preferably comprises a flange, which is attached to the film. The re-closing means is preferably a zipper.
The reclosing means sealing means preferably comprises a pressing means and/or a seal jaw. The pressing means is preferably two pairs of rollers, each pair provided on one axis.
Two rollers are preferably provided on each side of the film. The two pairs of rollers are preferably provided at a distance to each other, which is large enough to accommodate the middle part of the reclosing means.
Preferably, the re-closing means sealing means do not comprise means to guide the re-closing means, preferably the zipper.
According to a preferred embodiment of the present invention, the longitudinal-sealing means comprises pressing means, preferably a pair of rollers. One roller is preferably provided on each side of the film.
Preferably, the pressing force applied to the film applied by pressing means of the longitudinal sealing means and the pressing means of the re-closure sealing means are adjustable independently from each other.
According to another preferred or inventive embodiment of the present invention, the vertical flow-wrapper comprises downstream from the longitudinal- and/or re-closing means sealing means a pair of rollers whose axis of rotation are provided parallel to the transportation plane of the two opposing ends of the formed film and not perpendicular to the transport direction.
The disclosure regarding this embodiment of the present invention also applies to the other embodiments of the present invention. Subject matters from one embodiment can be incorporated into other embodiments and vice versa.
The film passes though the pair of rollers. One roller is preferably provided on each side of the film. The rollers stretch the film prior to providing the cross seal.
Preferably, one or both of the two rollers are driven, preferably with a motor. The roughness of the surface of the rollers, particularly the driven roller, is preferably such, that the film can slip relative to the rollers.
Preferably, the degree of stretching can be adjusted, preferably by changing the angle under which the axis of rotation of the guiding rollers are provided and/or by changing the normal force applied to the film by the two rollers.
The gap between the jaws are preferably individually adjustable for the longitudinal seal and for the re-closing means sealing means.
Preferably, the heated parts of each sealing jaw are preferably supported close to the film.
The problem is also solved with a method to produce a re-closable bag comprising the following steps:
The disclosure regarding this embodiment of the present invention also applies to the other embodiments of the present invention. Subject matters from one embodiment can be incorporated into other embodiments and vice versa.
Another preferred or inventive subject matter of the present invention is a method wherein prior and/or after the application of the longitudinal seal the two longitudinally sealed ends of the film are stretched in a direction perpendicular to transport direction of the film, preferably by two rollers whose axis of rotation are provided parallel to the transportation plane of the two sealed ends of the formed film and not perpendicular to the transport direction.
According to this embodiment of the present invention, a slip of the film relative to the stretching means downstream from the longitudinal sealing means is desired. This can, for example, be accomplished by a pair of rollers, whose axis of rotation is not perpendicular to the transport direction of the film. The slip and/or stretch can increased or decreased by changing this angle and/or by changing the normal force on the film provided by the pair of rollers.
Preferably, prior and/or after the application of the longitudinal seal the ends of the film are stretched in a direction perpendicular to transport direction of the film.
The invention is disclosed referring to the figures of the attached drawings, by way of non-limiting examples. The disclosure applies to all embodiment of the present invention likewise.
In
A web of a film 4, especially a weldable plastic film 4, is supplied from a reel, which supplies the plane film continuously or intermittently to a form shoulder 3, which shapes the film web into a rather tubular form around a form-fill tube 2. In the context of the present invention, a “tubular form” of the bags or of the film means any cross-sectional form including a circular form or another form, and especially a rectangular or generally a polygonal form.
Longitudinal sealing means 5, which are provided downstream from the form shoulder, seal the edges to the film tube together. After sealing, the bottom of the bag 7 can be formed by a special bottom forming means, for example gusset-forming means. Finally, cross seals, extending preferably perpendicularly to the direction of flow of the film, are applied, especially by means of cross-sealing means 6. These cross sealing means 6 apply to the bag 7 not only a cross-seal closing the top of the bag 2, but these cross-sealing means 6 advantageously also provide, preferably simultaneously a cross-seal defining the bottom of the subsequent, upstream bag 2. The bags 2 produced are separated from one another by a cutting means, which are preferably incorporated into the cross-sealing means 6. Between the application of the bottom- and top-cross-seal of each bag, the bag is filled with the product, preferably an edible product. Parallel, at least partially regarding time and in terms of direction to the longitudinal seal, re-closure means for every bag, for example a zipper, is attached to the film. The vertical flow-wrapper may comprise gusset-forming means to form the bottom and/or the top of each bag.
The gap between the two parts of each sealing means 5, 24 can be adjusted, preferably automatically by means 20. They can move the sealing means 5, 24 together from a remote position to an operation position. Furthermore, the gap between the two jaws of the sealing means 5 and the sealing means 24 can be adjusted individually. This is preferably done manually.
Referring to
The device comprises a motor, which rotates one of the two sprockets 31, which counterrotate as depicted by the arrows with the reference signs X, Y. Connected to each sprocket is an eccentric 32. The skilled person understands that different means than sprockets can be used as counterrotating means. The eccentrics can be connected via connection means 33, here a rod. The rod 33 can be fixedly connected to one eccentric and guided in a recess of the other eccentric, as a floating bearing. At least one eccentric comprises a punch or a knife 34 to provide the eurohole in the film of a bag. The opposite eccentric may comprise an anvil and/or a counter-knife for the punch/knife 34.
The punch/knife, the anvil/counter-knife are preferably kept in the same orientation, preferably parallel to each other, at least while the cutting process takes place. The punch/knife and/or the counter-knive/anvil can move in a direction with a perpendicular component to the direction of movement 13 of the film tube 4 or bag 7.
The following describes an example of the possible movement of the two eccentrics 32:
When the left eccentrics is in a position between 12 o'clock and 3 o'clock the right eccentrics will be in a position between 12 o'clock and 9 o'clock and the punch/knife 34 and the counter-knife/anvil will cut the film to create a eurohole. The force for the cutting can be provided with a pneumatic cylinder as shown in
The motor 30 is preferable a servomotor but also other motors or a mechanical connection to the main machine can be used.
The eurohole is preferably provided into the longitudinal seal 11 of the bag. The film 4 is moving while the eurohole is punched.
The bag may comprise reclosing means 5.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19200515.5 | Sep 2019 | EP | regional |
| 20159691.3 | Feb 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/077172 | 9/29/2020 | WO |
