EP0461667A1 - Method and apparatus for wrapping products in stretchable film - Google Patents

Abstract

The invention relates to a method and an apparatus for wrapping products (1) supported if appropriate on a pallet 10) or the like in a tubular or hood-shaped stretchable film (2, 3), in particular product stacks in cuboid or right-parallelepipedal form comprising layers of products multiply palleted one on top of the other, in which the film section forming the side face wrapping is folded in concertina fashion and transversely stretched before drawing over the product and in which the film is at least temporarily pressed laterally against an abutment (12) during drawing over the product before releasing its lower edge section in the region of the lower product edge section (1') and/or of the pallet, and the lateral contact pressure is no longer applied when the film has come firmly into contact over the full height with the product or at least partially with the pallet, the film being pressed or moved inwards in relation to its drawing-over contour above or/and below the pressure-applying region and/or in the pressure-applying region before and/or during pressure application, or the drawing-over speed being reduced in the drawing-over end phase, or the film having to be pressed against the lifting space and/or the products or the pallet before releasing its lower edge section in a way known per se by a pressure-applying device in the lower region of the product or/and of the pallet, which device is to be disengaged again from the film when the film has come into contact with the lower end section of the products, the concertina-folding device or its concertina-folding rollers being used as the pressure-applying device. <IMAGE>

Description

The invention relates to a method according to the preamble of claim 1 and a device according to the preamble of claim 3 for performing this method. possibly.

Such methods and devices have become known in the meantime after the shrink film technology for the creation of loading units has recently lost considerable importance for technical and economic reasons and has essentially been replaced by the stretch film technology.

As part of the stretch film packaging process that has become known in the meantime, for the formation of loading units (which also includes, for example, a banderole process in which the piece goods to be wrapped are wrapped with the web-shaped stretch film), the stretch hood process has proven to be the creation of transport-safe and weather-resistant loading units proven particularly useful.

It has been shown, however, that when a stretch film hood is pulled over a piece of goods to be wrapped with it (i.e. generally a cuboid or cube-shaped piece of goods), the lower edge region of the stretch film hood of such a loading unit, which holds the piece goods or a the pallet supporting pallet in the finished state with a so-called "understretch" should (under particular with additional vertical stretch applied) has a tendency to extend over the underside of the piece goods to be wrapped or over the pallet or the like to support the pallet. at least partially pull up so that the property of a weather-resistant covering is endangered.

This (disadvantageous) effect is evident - in particular in the case of a stretch film hood which is not only stretched transversely but also is stretched vertically - in particular when the film guided by the (reef and stretch) lifting frame during the pulling-on process in the lower end section of the film wrapping already then slides off the lifting frame when the (substantially immediately) film section located above has not yet had the opportunity or time to fit closely to the piece goods or the pallet supporting the piece goods. It should be borne in mind that this technology does not deal with ideal stretch films that slide off the lifting frame or the like. Due to their contraction properties, they spontaneously apply to the piece goods or the pallet, but with real foils, for which this process takes a certain period of time.

From DE 90 01 319 U 1 (see FIG. 8 and associated description) it is already known to pivot clamping jaws mounted on the machine frame above the lowest position of the lifting frame to the sides of the pallet used there and to clamp the section of the stretch film hood located there hold before their lower edge is released by swivel brackets, but this measure obviously requires an additional and therefore greater effort with a correspondingly high susceptibility potential and is therefore in no way to be regarded as satisfactory or even optimal.

The present invention is therefore based on the object to improve the known generic methods and devices, in particular while avoiding the disadvantages described above, so that - even with a relatively high pulling speed - it cannot happen that the piece goods or any pallet supporting the piece goods or the like. is not undermined (as provided) with an understretch, this goal being to be achieved with components that are already present.

According to the invention, a first solution of the procedural part of the above object consists in the characterizing features of claim 1, while a second solution, which is preferably to be used in combination with the first solution, is characterized by the characterizing feature of claim 2.

To achieve an at least comparable effect, one could clearly see the lower edge section of a stretch film hood (while it is still in engagement with the lifting frame) with a strapping band or the like. provided to prevent the film from being pulled up (in particular due to a vertical stretch) and to ensure the desired understretch. However, such or a similar measure is associated with a not inconsiderable effort in every respect and is therefore highly undesirable both for technical and especially for economic reasons.

The solution of the device-related part of the above object according to the invention consists of the characterizing part of claim 3, whereby this solution differs from the prior art according to DE 90 01 319 U 1 essentially in that the already existing reefing device (or whose reefing rollers) is used, so that, to achieve the effect achieved according to the invention, there is practically no significant additional effort. It can only be seen to ensure that the reefing device is to be moved or pivoted accordingly, which can be achieved easily (and with little effort) by appropriate guides.

A preferred embodiment of the device according to the invention is described by the characterizing features of claim 4.

It should be pointed out that it is already known in principle from DE-OS 21 46 446 to use suction strips for packaging objects by means of plastic film.

Fig. 1

eine etwas schematische räumliche Darstellung eines mit einer Stretchfolienhaube zu überziehenden Stückgutstapels, wobei die Stretchfolienhaube aus einem Seitenfaltenschlauch gebildet wird, der in Fig. 1 an seinem freien Endabschnitt bereits von dem Hubrahmen aufgenommen worden ist;

Fig. 2

in einer Fig. 1 entsprechenden Darstellung die Anordnung gemäß Fig. 1 nach Bilden einer Stretchfolienhaube;

Fig. 3

in einer Darstellung gemäß den Fig. 1 und 2 die gemäß Fig. 2 gebildete Stretchfolienhaube nach dem/beim Querstretchen;

Fig. 4

in einer Darstellung gemäß den Fig. 1 bis 3 einen Zwischenzustand beim Überziehen des Stückgutstapels mit einer Stretchfolienhaube;

Fig. 5

eine Seitenansicht eines bügelförmigen (Hub-)Rahmenabschnittes nebst dessen Stütze in Richtung des Pfeiles V in Fig. 6 gesehen;

Fig. 6

eine Draufsicht auf zwei (von vier) bügelförmige (Hub-)Rahmenabschnitte;

Fig. 7

eine teilweise schematisierte Seitenansicht auf einen auf einer Palette abgestützten Stückgutstapel mit einem bügelförmigen Rahmenabschnitt sowie einer Andrückeinrichtung in der Überzieh-Endphase; und

Fig. 8

in einer Darstellung gemäß Fig. 7 (ausschnittsweise) die fertige Ladeeinheit.

The invention is explained below using an exemplary embodiment with reference to a drawing. It shows:

Fig. 1

a somewhat schematic spatial representation of a piece of goods to be covered with a stretch film hood, the stretch film hood being formed from a gusseted tube which has already been received by the lifting frame in FIG. 1 at its free end section;

Fig. 2

in a representation corresponding to FIG. 1, the arrangement according to FIG. 1 after forming a stretch film hood;

Fig. 3

1 and 2, the stretch film hood formed according to FIG. 2 after / during cross stretching;

Fig. 4

in an illustration according to Figures 1 to 3, an intermediate state when covering the packaged goods with a stretch film hood.

Fig. 5

a side view of a bow-shaped (lifting) frame section and its support seen in the direction of arrow V in Fig. 6;

Fig. 6

a plan view of two (out of four) bow-shaped (lifting) frame sections;

Fig. 7

a partially schematic side view of a piece goods stack supported on a pallet with a bow-shaped frame section and a pressing device in the final pull-over phase; and

Fig. 8

7 (detail) of the finished loading unit.

1 shows a block-shaped piece goods stack, generally designated 1, which consists of several layers of piece goods parts which are to be wrapped with a stretch film hood 2 in order to form a loading unit. The stretch film hood 2 is formed from a gusseted tube 3, which is fed to the device according to the arrows 8 from a gusseted tube supply (not shown), the free end of the gusseted tube 3 according to FIG. 1 already being provided by a lifting frame designated as a whole by 9 (after the gusseted tube has been spread open) 3) has been included.

As has been indicated in Fig. 2, the gusseted tube 3 is welded at a distance from its free end by means of a welding device 4, which consists essentially of two welding strips, so that a transverse seam 5 is formed, and above the transverse seam 5 by means of a not shown Separating device separated to form a stretch film hood 2, the side surfaces of which, in the state shown in FIG. 2, have already been essentially raised onto the lifting frame 9 (by means of a reefing device).

From the state shown in FIG. 2, the four bow-like (lifting) frame sections 9 ′, which essentially form the lifting frame and are assigned to the corner regions of the piece goods stack 1, are moved apart in the direction of the arrows 6 for the purpose of transverse stretching of the stretch film hood 2. After that 4 is stretched over the piece goods stack 1 by means of the lifting frame 9, which at the same time forms a reefing frame, FIG. 4 showing an intermediate state in which the piece goods stack 1 is already half-wrapped.

From the position shown in FIG. 4, the lifting frame 9, which can be driven by means of a drive (not shown), then moves further downward, finally into a position as can be seen in FIG. 7, only one single bow-like frame section 9 ′ being recognizable in FIG. 7 is, but the other bow-like frame sections 9 'are formed accordingly and are at the same height level.

Before the further wrapping process is explained in detail below, the specific configuration of the bow-like frame sections 9 'of the lifting frame 9 in the illustrated embodiment should be explained in particular in FIGS. 5 and 6, and reference should first be made to the fact that the piece goods stack 1 - As can be seen from FIGS. 1 to 4 - is supported on a (one-way) pallet 10 with a plate top 10 '.

As has already been stated, the lifting frame 9 consists of four substantially C-shaped bow-like frame sections 9 ', each of which is provided with a plurality of through bores 13, which are connected to a vacuum source, and each engages with one during operation with foils located section of the outside of the relevant lifting frame section 9 'open. The vacuum source indicated schematically in FIG. 6 is designated by 14.

Each bow-shaped frame section 9 'is supported with a support 17 (see FIGS. 5 and 6) formed by a curved, conical sheet metal, the supports 17 each having a recess 18 in the central region. Otherwise, the through bores 13 connected to the vacuum source 14 are connected to a control device 16 (see FIG. 6), by means of which the vacuum can be controlled.

As can be seen from Fig. 7, the bracket-like frame sections 9 'of the lifting frame 9 are moved in the illustrated embodiment during the pulling process slightly below the top 10' of the pallet 10, with Fig. 7 showing that the already in this intermediate position Side gusset tube 3 or the (side faces of) stretch film hood 2 essentially envelop the piece goods stack. Nevertheless - as can be seen from FIG. 7 - the film 2 or 3, which is still in frictional engagement with the bow-like frame sections 9 'of the lifting frame 9, does not yet adhere to the latter in the region of the lower section 1' and not yet applied to the pallet 10. If, in particular in the case of considerable vertical stretch of the film 2 or 3, the lifting frame 9 was disengaged from the film in the state according to FIG. 7, this could have the consequence that it extends beyond the underside of the stack 1 or the Pallet top 10, at least the upper layer 11 of the pallet 10 pulls upwards, so that the desired understretch does not occur, in which the film 2 or 3 engages under the upper layer 11 of the pallet 10 (see FIG. 8).

To ensure this, a pressure device 12, shown schematically in FIG. 7, is provided, in which it is in the illustrated embodiment, the (reefing rollers) of the reefing device, by means of which the gusseted tube 3 has previously been attached to the supports 17 of the bow-like frame sections 9 'of the lifting frame 9. The reefing rollers essentially forming the pressing device 12 are pressed in the position shown in FIG. 7 according to the arrow 15 on the piece goods 1 or in a somewhat lower position on the upper layer 11 of the pallet 10. Only then do the bow-like frame sections 9 'move downward according to the arrow 19, that is to say out of engagement with the film 2 or 3, wherein they have already been moved inwards according to the arrow 20 (ie onto the piece goods 1 or the pallet 10) will.

The result of the measures according to the invention is that the film 2 or 3 can rest "at rest" with an understretch section 21 on the underside of the pallet top layer 11 due to the pressure by means of the pressure device 12, the corresponding measure also evident on the bottom layer 22 the pallet is possible, as has been indicated in FIG. 8 with respect to the understretch section 21 'in a dash-dotted line, or in the case of one not on a pallet 10 or the like. supported loading unit immediately below the piece goods stack 1, as is readily apparent to the person skilled in the art.

It should also be pointed out that, within the scope of the inventive concept, numerous variations or modifications are evidently possible which go (far) beyond the exemplary embodiment described above and shown in the drawing. For example, the lifting frame does not of course have to consist of bow-like sections of the type in question (see FIGS. 5 and 6), but can, for example, consist of consist of a closed frame, the individual legs (for the purpose of transverse stretching) are telescopic.

Furthermore, the pressing device 12 can be designed in a wide variety of ways and, in particular, does not need to be a component of the reefing device, as is most expedient, but can, as has already been indicated, be realized, for example, by the fact that the lifting frame 9 held film 2 or 3 in the negative pressure applied through the through holes 13 are held firmly on the lifting frame, while this is possibly / preferably moved from its pull-over position in the pull-over final phase closer to the piece goods stack 1 and the film 2 or 3 is given the opportunity has to put firmly on the piece goods stack 1 or the pallet 10 or a part thereof, so that the understretch 21 or 21 'can then also be produced in an equivalent manner as in a normal "pressing device".

Claims (4)

Method for wrapping piece goods, possibly supported on a pallet or the like, with a tubular or hood-shaped stretch film, in particular piece or cube-shaped piece goods stacks consisting of multi-layer palletized layers, in which the film section forming the side surface wrapping before covering is reefed and stretched over the piece goods, and in which the film is at least temporarily pressed laterally onto an abutment and the side pressure is released when the piece is pulled over the piece goods before releasing its lower edge section in the area of the lower piece goods edge section or / and the pallet, if the film is firmly attached to the general cargo or at least partially to the pallet, characterized in that the film relative to its overlay contour above and / or below the pressing area and / or in the pressing area before and / or during the Press ns after is pressed or moved inside. Method for wrapping piece goods, possibly supported on a pallet or the like, with a tubular or hood-shaped stretch film, in particular piece-wise or cuboid piece goods stacks consisting of multi-layer palletized layers, in which the film section forming the side surface wrapping before covering is reefed and stretched over the piece goods, and in which the film is at least temporarily pressed laterally against an abutment and the side pressure is released when the piece is pulled over the piece goods before releasing its lower edge section in the area of the lower piece goods edge section or / and the pallet, if the film is firmly attached to the general cargo or at least partially to the pallet, in particular according to claim 1, characterized in that the covering speed is reduced in the final covering phase. Device for wrapping piece goods, possibly supported on a pallet or the like, with a tubular or hood-shaped stretch film, in particular cuboid or cube-shaped piece goods stack consisting of multi-layer palletized layer layers, preferably with several (in plan view) essentially L-shaped or C-shaped, arranged substantially in a (horizontal) plane, frame-like frame sections and these each holding bracket supports existing, drivable (reef and stretch) lifting frame on which the film section forming the side surface wrapping in front of Cover onto the piece goods by means of a reefing roller or the like. having reefing device, and by means of which the ruffled film is to be traversed before covering, in particular for carrying out the method after Claim 1 or 2, characterized in that the film (2 or 3) before releasing its lower edge section in a manner known per se by a pressing device (12) in the lower region of the piece goods (1) and / or the pallet (10) to the displacement (9) and / or the piece goods (1) or the pallet (10) is to be pressed, which is to be disengaged from the film when the film (2 or 3) at the lower end portion of the General cargo (1) and possibly the upper end section (11) of the pallet (10), the reefing device or its reefing rollers (12) being used as the pressing device. Device according to claim 3, characterized in that the lifting frame (9) is provided with line openings (13) which open in the area of its engagement surface with the film (2 or 3); and that the line mouths (13) are to be subjected to negative pressure in the pressing phase.

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