DK2910474T3

DK2910474T3 - Method and apparatus for wrapping an article with a tubular wrapping film

Info

Publication number: DK2910474T3
Application number: DK15000192.3T
Authority: DK
Inventors: Dirk Göbel
Original assignee: Beumer Gmbh & Co Kg
Priority date: 2014-02-25
Filing date: 2015-01-23
Publication date: 2016-11-07
Also published as: EP2910474A1; DE102014002944A1; EP2910474B1

Description

The invention relates to a method and a device for enclosing an object with a tubular packaging film, for example in accordance with DE 3918311 A1 or in accordance with GB 1 476 170.

When packaging objects as for instance stacks of piece goods with a tubular packaging film, which in the delivery state is rolled up web-like, folded flat in the form of a supply roll, problems often occur when the film is opened into an open tube and/or a film hood due to electrostatic charges of the film. Such charges can already form when the required film portion is drawn off from the supply roll, and/or while the film portion is being transported from the supply roll to an opening station, where the film is opened, gathered up and finally pulled over the object to be packaged. The film can then be difficult to open or may adhere unmanageably to plant surfaces situated nearby, which may render the packaging method substantially more difficult to execute. US 3 209 513 discloses a device for film packaging, wherein a folded flat film, open on one side, is drawn off from a roll and anti-statically treated. An antistatic treatment of film material for packaging is also disclosed by US 5618252 and US 3209513.

The aim of the invention is to indicate a method and a device for enclosing an object with a tubular packaging film, as a result of which the aforementioned problem is solved in an improved way. The aim is achieved by the subject matters of the independent claims.

In order to achieve this aim the invention firstly proposes a method for enclosing an object with a tubular packaging film, comprising the steps: providing a supply of tubular, folded flat packaging film, drawing off the packaging film from the supply and transporting the packaging film to an opening station, separating a film portion required for an enclosing operation, transporting the packaging film before reaching the opening station by frictional engagement between at least two infinitely rotating conveying elements pressed against each other, moving in a transport direction, whereby the conveying elements at a delivery end are diverted around two parallel re-direction rollers and separated from one another, opening the film portion, gathering up the film portion on gathering apparatus and enclosing the object, the film portion being anti-statically treated before and/or during opening, at least in sections, and electrostatic charges on the packaging film being neutralized, at least partly, by the packaging film being anti-statically treated with rod-like ion generators, which in each case are arranged parallel and adjacent to a re-direction roller arranged at the delivery end and whereby the first and/or second conveying element is formed as transport belt, which is electrically conductive, at least in sections.

Preferably it is proposed that the ion generators are arranged outside an internal area surrounded by the tubular film portion so that in particular outer faces of the film portion are anti-statically treated or applied with ions. As a result the conveying elements can also be anti-statically treated at the same time as the film material.

It may be proposed that the entire film portion is anti-statically treated before and/or during opening.

The packaging film can be supplied and fed as gusseted tube, comprising a front panel, a rear panel and two side panels folded in between, the front panel and the rear panel being anti-statically treated before and/or during opening.

It may be proposed that the side panels are also anti-statically treated inside and/or outside after start of opening.

Ion generators can be arranged within the internal area of the film portion, in order to anti-statically treat inner faces of the film portion.

Preferably the invention proposes that the packaging film is separated before reaching the opening station, for instance immediately after a required film length has been drawn off and the packaging film is transported to the opening station in the form of the separated film portion.

The packaging film can be opened after leaving the conveying elements, whereby the front- and rear panels in the region of the conveying elements lie on top of one another and are opened the other way round in a V-shape and anti-statically treated after leaving the conveying elements.

The anti-static treatment can include monitoring or detecting the electrostatic charge of the packaging film, ion generation by means of discharging electrodes and air flushing directed from the discharging electrodes to the packaging film. The ion generation can be controlled, for example depending on the charge of the packaging film detected, and the air flushing can be controlled, for example likewise depending on the electrostatic charge of the packaging film. The intensity of the ion generation and/or flow rate of air flushing can also be controlled depending on a draw-off speed of the packaging film, at which this is transported to the opening station.

In order to assist the anti-static treatment it may be proposed that the conveying elements are constantly discharged in operation.

Furthermore the aim, on which the invention is based, is achieved by a device for enclosing an object with a tubular packaging film, comprising: a supply of tubular, folded flat packaging film, draw-off means for drawing off the packaging film from the supply, separation means for separating a film portion, film transport equipment for transporting the packaging film to an opening means, whereby the opening means has grab elements for gripping the film portion, the film transport equipment comprising a first infinitely rotating conveying element and a second infinitely rotating conveying element, pressed against the first conveying element, which can be driven in a transport direction and between which the film portion can be frictionally engaged between the separation means and a delivery end, gathering apparatus for gathering up the film portion, a covering device for enclosing the object with the film portion, means for neutralizing electrostatic charges on the packaging film, arranged at the delivery end of the film transport equipment which is situated at a distance above the opening means; said means for neutralizing electrostatic charges being formed by two or more rod-like ion generators, which in each case are arranged parallel and adjacent to one of two parallel re-direction rollers of the film transport equipment arranged at the delivery end, whereby the first and/or second conveying element is formed as transport belt, which is electrically conductive, at least in sections.

The ion generators are preferably arranged outside an ion region surrounded by the tubular film portion so that in particular outer faces of the film portion are anti-statically treated and/or applied with ions. Expediently each ion generator is situated at a distance of not more than 10 mm, 20 mm, 50 mm, 10 mm, 150 mm or 200 mm from an adjacent re-directed conveying element.

Ion generators can be arranged within the internal area in order to anti-statically treat inner faces of the film portion and/or to apply them with ions.

The film transport equipment is suitable both for the transport of packaging film, which has been drawn off from the supply, and also for the transport of an already separated film portion, in each case depending on where the separation means is spatially arranged.

The grab elements can concern grab tongues or alternatively vacuum grippers, with which the packaging film and/or the film portion at a front end can be gripped, opened and pulled onto the gathering apparatus by suction effect.

It may be proposed that a film path, along which the film portion is moved, opened and gathered up, is formed between the delivery end of the film transport equipment and the gathering apparatus, the means for neutralizing electrostatic charges being situated at a distance of up to 300 mm, 200 mm, 150 mm 100 mm, 50 mm, 20 mm or 10 mm from the film path. Furthermore it may be proposed that the means for neutralizing electrostatic charges is situated at a distance of up to 300 mm, 200 mm or 100 mm from the delivery end of the film transport equipment.

The invention also proposes that the first and/or second conveying element is formed as transport belt, which is electrically conductive, at least in sections. The transport belt can be formed in multiple layers with at least one layer, which is electrically conductive, at least in sections. The electrically conductive layer may be provided with metal threads, metal braiding or carbon fibres. It may be proposed that a surface coming into contact with the packaging film of the first and/or second conveying element is electrically conductive, at least in sections. For example metal braiding, metal wires arranged parallel to the direction of travel or a conductive coating can be provided on the surface.

It may be proposed that each rod-like ion generator is equipped in the longitudinal direction one behind the other with a set of ion nozzles, which work by means of corona discharge and with air flushing in each case. Each ion nozzle has a central discharging rod with discharging point and an air flushing channel concentrically surrounding this, which in turn is surrounded by a circular counter electrode connected to an earth plate. The discharging rod and the earthed counter electrode in operation are connected to a high-tension, for example five or six kV AC, whereby an air flow generated by the air flushing duct in the direction of the packaging film to be discharged produces an intensive transport of ions. The AC in particular can be pulse-modulated, in order to generate a maximum ion generation cycle. Depending on polarity of the charge of the packaging film to be discharged, the positive or negative pulse phases of the pulsed AC can be increased in terms of voltage or given a larger pulse width, so that flexible ion generation (positive or negative ions) is possible. From a circuitry technical aspect in the sense of an equivalent circuit diagram here the discharging rod is controlled alternatingly longer or shorter in the cycle of the AC (high frequency) connected to positive or negative DC (high voltage), due to which controlled polarity of the generated ionic cloud results. The invention is described below on the basis of an exemplary embodiment, reference being made to a drawing, wherein

Fig. 1 is a schematic perspective view of a device according to the invention for enclosing an object with a packaging film.

Fig. 2 is a view of the device in accordance with Fig. 1 from another direction. Fig. 3 is a schematic lateral view of the device in accordance with Fig. 1,

Fig. 4 is an enlarged partial view of the illustration in accordance with Fig. 2,

Fig. 5 is an enlarged partial illustration of the lateral view in accordance with Fig. 3,

Fig. 6 is an enlarged partial illustration from Fig. 1, and

Fig. 7 schematically shows an alternative embodiment with several partial conveying elements.

The illustrations show a device known in principle for covering a stack of goods 2 with a tubular packaging film 4, which usually concerns a stretch film, in contrast to the shrink wrap applied to the stack of goods by means of heating as mainly used earlier.

The device has a holder, not illustrated in detail, to accommodate a film roll 6, which constitutes a supply of packaging film 4, the film being rolled up in the form of a gusseted tube, in which a front panel and a rear panel lie on top of one another with side panels folded in between. A re-direction roller 8 and a pair of feed rollers 10 for example represent film draw-off means, which can be controlled, in order to draw off a film portion in a pre-determined length. Separation or cutting means 12 with a knife arranged transversely to the film, seen in the unwinding direction 5 of the packaging film 4, and a welding unit 14 with welding bars 14a, b arranged on both sides of the film, are located beneath the film draw-off means 8,10.

Underneath the cutting and welding units 12, 14 an inlet region 18, directed vertically downwards, of the film transport equipment 20, which works in a transport direction 21 and essentially consists of two infinitely rotating conveying elements in the form of transport belts 22, 24, which within a transporting region, that begins with the inlet region 18 and ends with a delivery region 26, are pressed against one another, at least in places. The film transport equipment conveys the film portion, separated and welded on one side over its full length, a longitudinal direction of the film portion coinciding with the transport direction 21.

Fig. 7 schematically shows that the film transport equipment may not only consist of two conveying elements, but that each conveying element can be formed from two or more partial conveying elements following each other in the transport direction, which are mutually complementary to one another. For example a first conveying element can consist of two first partial conveying elements 22.1, 22.2, which for example can be formed as transport belts and/or partial transport belts and face a uniform second conveying element 24 in the form of a transport belt, the packaging film 4 and/or a film portion 7 being frictionally engaged between the conveying and/or partial conveying elements pressed against each other.

In the illustrated embodiment firstly a horizontal conveying region 28, in which the transport belts 22, 24 substantially run horizontally, follows the inlet region 18. A vertical, upwardly running conveying region 30 adjoins the horizontal conveying region 28, in the course of which the transport belts 22, 24, lying next to one another, are re-directed several times around horizontal re-direction rollers 32 in alternating directions slightly deviating from the vertical, so that the transport belts 22, 24 are pressed against one another as much as possible over the major part or entire length of the vertical conveying region 30. A horizontal transfer area 34 which ends with the delivery region 26 directed vertically downwards within a lifting unit frame 36 of the device adjoins the vertical conveying region 30. The delivery region 26 with delivery end 26a is located above an opening station or film opening means 40, which has means for gripping and opening the film.

The conveying elements are diverted on two parallel re-direction rollers 26b and separated from each other, the film portion transported in-between up to this point being released or delivered.

Fig. 4 shows that four grab elements 40a are present in the form of vacuum grippers, with which a front panel 4a and a rear panel 4b of an end section of the film portion 7 can be gripped in each case by two vacuum grippers and opened as a tube, whereby the first still folded side panels 4c of the tubular film are unfolded and an open film tube or film hood sealed on the end side, which is gathered up on gathering apparatus 44, is formed. A vertically displaceable covering device 42, which in the exemplary embodiment illustrated has four gathering fingers 44 arranged in the corners of a square or rectangle as gathering apparatus for taking over and gathering up a film portion 7, is located below the film opening means 40. The covering device 42 can be displaced vertically between a covering start height H illustrated in Figs. 1 and 2 up to a covering end height h, in order to pull a separated film portion over the stack of goods 2.

The covering start height H is dimensioned so that stacks of goods 2 are to be processed problem-free with a greatest possible height from the device, while the covering end height h lies just below a lower edge 2a of a stack 2, so that the film can be pulled over the stack if necessary with “under-stretch” gripping below the lower edge 2a.

The stack of goods 2 itself is located on a conveyor system 48 at a vertical distance F over a hall level 50, on which the device is situated and from which jobs, as for example maintenance or repair work and exchange of the film roll 6, are performed on the device.

In order to be able to undertake jobs on the feed rollers 10, cutting means 12 and welding equipment 14 as well as to exchange the film roll 6 in a simple way for example by an operative, standing on the hall level 50, the device elements mentioned should not be higher than for example 1.5 m above the hall level 50, so that these can be accessed without difficulty. The film roll 6 may be arranged more highly, for example up to 2 m or even higher, since it is not usually moved directly by an operative but by means of transportation equipment, for example a fork-lift truck.

Irrespective of whether a hall level 50 is present as “datum level” for advantageous positioning of the draw-off means and cutting and welding equipment, it is generally advantageous if the devices mentioned are below the covering start height H, to be precise expediently within a film preparation region V, which extends from below the covering end height h up to maximum 50% or 75% of the covering start height H.

According to the invention means for neutralizing electrostatic charges of the packaging film 4 is arranged adjacent to the delivery end 26a of the film transport equipment 20 which in the illustrated embodiment comprises two rodlike ion generators 60.

The ion generators 60 are always parallel and adjacent to a re-direction roller 26b of the film transport equipment 20 arranged at the delivery end 26a. As shown by Fig. 5 a film path 62, along which the film portion 7 is opened and gathered up with approximately other way round V-shaped run of the front- and rear panel 4a, b, is formed between the delivery end 26a of the film transport equipment 20 and the gathering apparatus 44. The ion generators 60 are preferably located outside an internal area surrounded by the tubular film portion, so that it is possible not only to anti-statically treat the film material with ions but also the conveying elements just separated from each other and therefore possibly particularly electrostatically charged.

Each ion generator 60 has a number of ion nozzles distributed over its entire length for example at least 5, 10, 20 or 30 individual ion nozzles, which are directed to the front- and rear panel 4a, b of the opened film portion 7. The ion generators 60 preferably have a length L, which coincides with a width B of the opened film portion 7 or with a width of front panel and rear panel of the film portion. Optionally further ion generators can be arranged adjacent to the side panels 4c, which when the film portion 7 is opened up from its folded position are transformed into a position substantially even and arranged perpendicularly to front- and rear panel. These additional ion generators can be shorter than the ion generators 60 assigned to the front- and rear panel, and they can project into a region, which lies between two facing grab elements 40a and below the lateral ends of the re-direction rollers 26b, so that as small a distance as possible from the side panels 4c to be opened is obtained.

The ion nozzles of the ion generators 60 can be adjustable in order to optimize the neutralization effect. The voltage applied and/or its pulse modulation and/or the air flushing of the ion nozzles can be controlled depending on the charge intensity of the film portion and on the speed, at which the film portion runs past the ion generators.

Reference symbol list 2 Stack of goods 2a Lower edge 4 Film 4a Front panel 4b Rear panel 4c Side panel 5 Unwinding direction 6 Film roll (film supply) 7 Film portion 8 Re-direction roller 10 Feed rollers 12 Cutting means (separation means) 14 Welding equipment 14a, b Welding bars 18 Inlet region 20 Film transport equipment 21 Transport equipment 22 First transport belt (conveying element) 22.1,22.2 First partial transport belt (partial conveying element) 24 Second transport belt (conveying element) 26 Delivery region 26a Delivery end 26b Re-direction roller 28 Florizontal conveying region 30 Vertical conveying region 32 Re-direction rollers 34 Transfer area 36 Lifting unit frame 40 Film opening means 40a Grab element 42 Covering device 44 Gathering finger (gathering apparatus) 48 Conveyor system 50 Hall level 60 Ion generator 62 Film path B Width (of 4a, b) H Covering start height h Covering end height F Distance between 48 and 50 L Length (of 60) V Film preparation region

Claims

A method of wrapping an article (2) in a hose-shaped wrapping film (4), comprising the steps of: - preparing a stock (6) of hose-shaped, flat-folded wrapping foil (4), - removing the wrapping foil (4) 4) from the storage (6) and transporting the wrapping foil (4) to an opening station (40), - separating a foil section necessary for a wrapping procedure, - transporting the wrapping foil (4) before reaching the opening station (40) by frictionally, the endless orbiting conveying means (22, 24) moving between at least two mutually contradicting, reciprocally displaced conveying means (22), and the conveying means (22, 24) at a delivery end (26a) run about two parallel by-pass rollers (26b) ) and separated, - opening the foil section (7), - collecting the foil section (7) on a collection device (44) and wrapping the object (2), characterized in that the foil section (7) ) before and / or during the opening, at least regionally treated antistatically, and electrostatic charges on the wrapping foil (4) at least partially neutralized, the wrapping foil (4) being treated antistatically by rod-shaped ion generating means (60) which are parallel at all times with and disposed adjacent to a by-pass roller (26a) arranged at the delivery end (26b), and that the first and / or second conveying means (20, 22) are formed as a at least regionally electrically conductive conveyor belt.

Method according to claim 1, characterized in that the ion-generating means (60) are arranged outside an inner region of one of the tubular film sections (7).

Method according to claim 1 or 2, characterized in that the wrapping foil (4) is stored and supplied in the form of a side foil hose with a front wall (4a), a back wall (4b) and two interposed side walls (4c), and and / or during the opening of the front wall (4a) and the back wall (4b), antistatic treatment of these walls is performed.

Method according to claim 3, characterized in that after the opening is started, the side walls (4c) are also treated antistatically.

Method according to one of the preceding claims, characterized in that the wrapping foil (4) is opened after leaving the transport means (22, 24) and that the front wall (4a) and the back wall (4b) lie in the area of the transport means (22, 24). against each other, and after leaving the transport means (22, 24) is opened in the reverse V way and treated antistatically.

Method according to one of the preceding claims, characterized in that the antistatic treatment comprises monitoring or sensing the electrostatic charge on the wrapping foil (4), producing ions by means of discharge electrodes and one from the discharge electrodes directed to the wrapping foil (4). air flow.

Method according to one of claims 5 to 7, characterized in that the conveying means (22, 24) are continuously discharged during operation.

Apparatus for wrapping an article (2) with a hose-shaped wrapping film (4), comprising: - a stock (6) with a hose-shaped, flat-folded wrapping foil (4), - a peeler for pulling the wrapping foil (4) from - a separating device for separating a foil section (7), - a foil transporting device (20) for transporting the wrapping foil to an opening device (40), which opening device (40) has gripping means (40a) for gripping the foil section (7). ), and that the foil conveying direction (20) comprises a first, endless, circumferential conveying means (22) and a second, endless, circumferential conveying means (24) pressed against the first conveying member (22), which can be operated in a conveying direction (21), and wherein, under friction, the film section (7) can be moved between the separating device (12) and a dispensing end (26a), - a collecting device (44) for joining the film section (7), - a coating device (41) for wrapping the article (2) having the film section (7), characterized in that a device (60) for neutralizing electrostatic wires is provided on the wrapping film (4), which is arranged at the delivery end (26a) of the film transport device (20), located at a distance above the opening device (40) and in that there are two or more rod-shaped ion generating means (60) arranged parallel to and adjacent to two parallel by-pass rollers (26b) arranged in the delivery end (26a) the foil conveying device (20), and that the first and / or second conveying means (20, 22) are at least configured as a regionally electrically conductive conveyor belt.

Apparatus according to claim 8, characterized in that the ion generating means (60) is arranged outside an ionic region enclosed by the tubular film section (7).

Apparatus according to claim 8 or 9, characterized in that between the dispensing end (26a) of the foil transport device (20) and the collecting device (44) a foil web (62) is formed, along which the foil section (7) is opened and collected, and the generating means (60) is arranged at a distance of approx. 300 mm, 150 mm or 50 mm from the film web (62).