DE4307287C2 - Process for wrapping a stack - Google Patents

Description

The invention relates to a method for wrapping one formed from a plurality of objects Stack of stretchable film, one film hose pulled off a film supply, opened and according to the height of the stack to be wrapped separated and closed to form a hood that Hood from a hood covering device with we at least four ver in the horizontal and vertical directions sliding reefing fingers is taken over by the Reffinger by moving horizontally into the four corners intervene in the hood, then the hood bellows-like around the fingers, then by extending the reefing fingers horizontally to one larger floor plan than that of the stack horizontally pulled and then pulled over the stack and from their raised position to the sta pel is released.

Such a method is, for example, from EP 0 344 815 A1 known. In this known method the film formed from a film tube becomes Cover over the stack of goods to a larger one Floor plan drawn up as that of the stack and then connected eating with the approval of the reefers over the Sta pel pulled. The film hood lies down due to this their stretch film properties then automatically tight to the stack.

These known methods work perfectly, if stack of goods is formed or with a film hood are coated, which a con have constant cross-sectional area. However, it has emphasized that when stacking goods with the height different cross-sectional area, for example at Commission pallets with La growing down scope, problems, especially overstretching the film can occur, causing damage to the Foil and thus a reduction in transport stability of the pallet loads.

From GB 1 333 125 it is used for covering Sta peln with laterally offset to each other above the height Layers with the same cross-sectional area known that the Reffinger daring frame and thus the Reffinger to proceed horizontally in this way during the vertical movement ren that the distance of the reefing fingers towards the corner areas of the stack is approximately constant. By such a horizontal shift of the reef finger supporting frame can be the aforementioned Pro Bleme with one, for example from EP 0 344 815 A1 however, do not solve known methods.

From DE 90 06 384 U1 is a device for order known to wrap a stack with stretchable film, which distance in the frame carrying the fingers has sensors which under the pulling process break when the fingers or the frame come together the vertical movement too close to the stack. Out DE 40 19 041 C1 is a method for wrapping a stack of stretchable film known, at wel chem for storing the hood opening in multiple layers randes in the area of the bottom of the stack or on the pa lette the frame is opened and closed and at Raising and lowering the frame under the finger be moved apart at different distances. Both before However, the fonts mentioned do not contain any references se to solve the problems outlined.

The object of the invention is therefore to provide a solution create with the also stack of goods with over the height different loads with Fo lienhaube can be covered, with excess of the film hood can be reliably avoided should.

This task is done using a method of a gangs referred to according to the invention thereby ge solves that for wrapping a stack with over height of the same increasing and decreasing cross-sectional area, the reef opposed during their vertical relative movement above the stack in line with the contour of the sta pels are moved horizontally, such that the ver through the opening of the hood shrinks or enlarges and that the distance of the ref fingers opposite the corner areas of the stack in each case is about constant. The reef finger movement be carried out continuously or discontinuously.

It is with the procedure according to the invention without complex constructive changes to the requ device due to the corresponding Control of the horizontal movement of the reef fingers possible Lich, the position of the Reffinger and thus the film be in the vertical movement of the same and in the over pull over the stack exactly to the contour of the Adjust stack of goods so that the current of areas of the film hood released to the refingers approximately constant distance from the respective um beginning of the stack of goods and thus almost even stripping and releasing the hood from the Reffingers. This causes overstretching conditions of the film and any damage, even with such Reliable avoidance of stack configurations.

In an advantageous embodiment of the invention provided that the distance of the reefing fingers is opposite continuously monitor the corner areas of the stack and by horizontally moving the reef finger regu is gated. This procedure is special then provided if in a device often un Different stacking configurations with foil over should be pulled. Be over a long period of time constant material stack configurations ver such monitoring is not required Of course, it is more than enough if it corresponds appropriate contour of the stack of goods in the control of the Device is entered and then the Reffinger ver automatically according to the contour of the stack will drive.

In an advantageous embodiment, that before wrapping the stack the geometric Dimensions of the same in a control device Hood covering device can be entered. It is of course also possible, then just if to monitor the position of the reefing fingers and readjust if necessary.

To enter the stack dimensions is special ders advantageously provided that the input via a Coding is done on at least one of the counter stands of the stack or on a pallet-shaped un terlage of the stack is attached. The respective code tion can then be removed from a scanner, for example read and entered accordingly in the control become.

It is particularly advantageous that the foil hood is selected because of the contour of the sta pels horizontally retracted position of the finger in Vertical direction is stretched and / or that the Fo lienhaube during pulling on due to the Contour of the stack in the horizontally extended position the reef finger is relaxed in the vertical direction. This additional refinements are special  Advantage if the differences in cross-sectional areas of the stack are pronounced above the height. Although the Foil hood a constant over its height Cross-sectional area, which is advantageous, for example adheres to an average cross-sectional area of the Sta pels is adapted, can then by this special Ver driving guidance to be ensured that at piling range with a smaller cross-sectional area, i.e. with ent speaking horizontally retracted reefers, which in this area inevitably less horizontal ge stretched film is additionally stretched vertically by one to achieve better investment on the stack. On the other hand is reliably guaranteed that in stack areas with a larger cross-sectional area, i.e. horizontal reefing fingers, the foil hood not overstretched when pulling off the reefing fingers gets or tears because of the greater horizontal stretch or stretching the hood by relaxing in vertical direction is compensated.

This vertical stretch is generally suitable or relaxation of the film hood, if one after the other in a device (with regard to on the cross-sectional area) goods of different sizes stack with a constant cross across the height cut surface are wrapped, but in each case Fo lien hoods of the same size should be used len. So are larger cuboid stacks around wraps, the film hood is ent in the vertical direction tense; become smaller stacks with one of the Same size hood wrapped, the Foil hood additionally in vertical direction stretched or stretched.

It is especially beneficial if the stretching gene of the film hood in horizontal and / or vertical Direction measured and with a predetermined target worth comparing and then stretching the film hood is readjusted in the vertical direction. It is then possible to optimally use the film hood firmly attached to the stack of goods without the risk of overstretching bring contour to the system. The pre-hang specified setpoints for the extension or Stretching of course depends on the material properties and dimensions of the used Slide off.

The invention is based on the drawing for example explained in more detail. This shows in

Fig. 1 is a simplified side view of an apparatus for carrying out the method according to the invention,

Figs. 2 to 6 each in a simplified side view stages of a device according to Fig. 1 in different process,

Fig. 7 shows a stack of goods with several different areas and areas

Figs. 8 to 10 are each in a simplified representation the Reffinger the device with associated drive roll in a different operative position.

Throughout the figures, the same reference characters are used for the same parts. A device for carrying out the method according to the invention is initially shown in more detail in FIG. 1.

Within a device frame 1 with a pre förderter of this stack 3 is arranged on a roadway. 2

This stack 3 consists for example of a plurality of stacked bags or the like., Which in the illustrated embodiment, the base surface varies over the height of the stack 3 of the Gutsta pels from top to bottom. Here, resting on a pallet 3 a first, a lower Gutstapelbereich 3 b whose base corresponds approximately to the base surface of the pallet 3 a. In this Gutstapelbereich 3 b 3 is arranged a Gutstapelbereich c having a smaller footprint. The transition area is indicated by arrow 3 d.

A roller 4 is mounted in the frame 1 , on which a plastic tube 5 made of stretchable material is wound with side gussets. Stretchable material is understood to mean one which, after being pulled apart or stretched, returns to the state it was in before stretching. The with folded side edges on the roll 4 hose 5 is fed via deflection rollers 6 and drive rollers 7 to a threading device, which consists of the area of the folded hose edges vertically movably arranged guide elements 8 , below which a separating device 9 and a welding device 10 are arranged.

Below the guide elements 8 , two roof-shaped double conveyor belts 11 are arranged on both sides of the frame, the upper receptacle ends being located directly below the guide elements 8 in the lowered position.

A swivel lever 18 is assigned to each double conveyor belt 11 , with each swivel lever 18 lying somewhat inwardly of the assigned double conveyor belt 11, viewed in plan view.

In the frame 1 and in the vicinity of the four corners of the same endless circulating chains are stored (not shown in the drawing) to which a carriage 12 is attached parallel to the road direction, each with two vertical reefing fingers 13 with a head 14 . Each reef finger 13 is adjustable both in the vertical and in the horizontal direction, a corresponding Antriebseinrich device is shown generally in Fig. 1 and 15 be. At the upper end of each reef finger 13 , a drive roller 16 is assigned to the outside, which can be moved horizontally in FIG. 1 in a direction not shown in the direction of the reef finger 13 into the active position shown again in FIG. 2.

A process flow according to the invention with the The device described above is as follows:

The flat-lying stretch film tube 5 is threaded through the drive rollers 7 via the guide elements 8 , which are in the lowered position when the device is started. At the lower end of the guide elements, each folded edge of the hose is passed between a double conveyor belt 11 , which causes the hose to be opened. After the lower end of the hose has run a bit out of the double conveyor belts, the drive of the Antriebsrol len 7 and the double conveyor belts 11 are stopped and the reefing fingers 13 are driven into the lower end of the hose. After retracting the reefing fingers are held so that the tube is at its four corners around the reefing fingers 13 ( Fig. 2).

Then the drive rollers 16 are moved up to the refin ger and put into operation, namely together with the drive rollers 7 and the double conveyor belts 11 until the height of the stack 3 corresponding length of hose around the reefing fingers 13 have been placed in a bellows-like manner. Subsequently, the to be drive rollers 7, the double conveyor belts 11 and drive rollers 16 to again stopped and the drive rollers 16 moved radially outwardly (FIG. 3). The separating and welding devices 9 and 10 are actuated. After the separation and welding process has ended, the double conveyor belts 11 are actuated again and, at the same time, the pivot levers 18 are pivoted downward, as a result of which the folded tube edges are pushed or pulled out of the receiving ends of the double conveyor belts.

As soon as the hose is released from the double conveyor belts 11 , the reefing fingers are moved into the spreading position shown in FIG. 1, this spreading position or the position of the reefing fingers 13 according to the invention being regulated or set as a function of the base area of the stack of goods 3 .

The arrangement of the Reffinger 13 is initially so, as shown in Fig. 4, ie, the Reffinger 13 are so far moved radially outwardly that they c problems on the base of the stack area 3 can be moved, whereas for the larger Base area 3 b is not possible. This position of the reefing fingers 13 is also shown in FIG. 1 and designated 13b.

Immediately after taking the position of the reefing finger 13 given in FIG. 1 and thus the film hood designated 17, the stack of goods 3 is raised beyond the carriageway 2 and the chains, not shown, are driven in such a way that the carriage 12 engages with the thus coupled reefing fingers 13 and the hose 5 of the hood 17 located on the latter in the stretching position in waves are moved downwards along the stack. The upper ver closed end of the formed by welding th hood 17 on the surface of the stack 3 , so that upon further pulling of the corrugated hood 17 wave after wave pulls up and surfaces according to their release from the spread position to the sides of the stack 3 creates (see Fig. 4).

Now get the spreading fingers 13 in the transition area 3 d of the stack of goods 3 and thus in the area 3 b of the stack of goods with a larger base area, so the reefing fingers 13 are moved horizontally outwards in adaptation to the contour of the stack 3 ; this position is shown in FIG. 5 and, for the sake of clarity, also in FIG. 1, this position of the reefing finger being indicated there with 13a. The reefing fingers 13 are preferably moved outwards to such an extent that the distance between the reefing fingers and the corner regions of the stack essentially does not change, ie the reefing finger position is adapted to the contour of the stack of goods. In this position the reefing finger 13 (position 13 a) the remaining stack 3 is then covered with the hood 17 in a known manner.

It goes without saying that other stacked configurations can also be packaged exactly as described. For example, the stack of goods 3 could also have a plurality of regions of different base area or an approximately conical arrangement could be provided, in which case the refingers are continuously adapted to the contour of the stack of goods during the vertical movement.

In addition, it can be provided that the position or the distance of the fingers 13 from the stack 3 is monitored and then regulated if necessary. A suitable measuring device for distance measurement is then required, which is not shown in detail.

If stacks of material with a constant contour are used over a longer period of time, it is also sufficient if the geometric data of the stack of goods are entered into the control of the hood covering device (Reffin ger 13 ).

The Reffinger are then accordingly from the Control automatically during vertical movement too in line with the contour of the stack of goods horizontally method.

For entering this geometric stacking data can the stack of goods ver with a suitable coding be seen, for example, with a scanner sen and the control device can be entered. With appropriate programming of the control can of course also without additional Monitoring equipment and without retrofitting successively stacks of goods with different geome dimensional dimensions.

In Fig. 7 another Gutsta stack 3 'is shown for clarity, which has several areas of different areas across its height, which in an individual from bottom to top with 3a', 3b ', 3c', 3d ', 3e' and 3f 'are designated. According to the invention, the reefing fingers 13 are then moved horizontally inwards or outwards in adaptation to this contour. This is indicated by the dashed line denoted by 13 in FIG. 7, which indicates the respective position of the reefing fingers 13 above the height.

For such stacks of goods ( Fig. 7), which have significantly different base sizes over the height, it is additionally advantageously provided that the foil hood 17 is stretched or relaxed in the vertical direction depending on the horizontal position of the refiner 13 , this being schematically detailed is shown in FIGS. 8 to 10.

For this purpose, the drive rollers 16 are moved up to the film hood 17 in such a way that a vertical relative movement of the film hood 17 relative to the reefing fingers 13 is possible.

Depending on the size and dimensioning of the film hood 17 , in the area 3 f 'of the stack 3 ' of FIG. 9, the film hood 17 which is placed in folds on the reefing finger is additionally moved or rotated vertically relative to the vertical movement of the reefing finger 13 by rotating the drive rollers 16 in the opposite direction, which either leads to a vertical stretching of the film hood 17 or to a vertical tensioning thereof. In the area 3 e 'of the stack of goods 3 ', that is to say in an area with a larger base area, the horizontal movement of the refining device 13 causes a greater horizontal expansion of the film hood 17 outwards, so that in this case ge according to FIG. 10 the drive rollers 16 are rotated in the direction of the arrows there ( FIG. 10), ie the film cut 17 is relaxed in the vertical direction and can be removed more easily from the reefing fingers 13 . This reliably prevents the fact that with greater horizontal expansion due to the larger base area of the stack, the film hood 17 is overstretched or torn.

Depending on the size of the film hood is then in the area 3 d 'of the stack of goods 3 in accordance with the area 3 f' in turn a vertical expansion or unloading.

In the area 3 c 'of the stack of goods 3 ', that is to say in an area with a significantly smaller base area, the film hood 17 is only slightly stretched by the horizontal retraction of the finger 13 in the horizontal direction. In order to ensure that the film hood 17 is still in perfect contact with the stack of goods 3 in this area, the film according to FIG. 8 is stretched or stretched in the vertical direction by driving the drive rollers 16 accordingly.

Then in the area 3 b ', depending on the size of the film hood, as in the areas 3 d' and 3 f ', again a vertical expansion or relaxation, or the drive rollers 16 are out of action, so that the relative movement of the film hood 17 with respect to the reefing fingers 13 is influenced in the vertical direction by the drive rollers 16 .

In region 3 a ', a tension of the film hood in the vertical direction is then effected in a manner corresponding to region 3 e' in accordance with FIG. 10 by a corresponding rotary movement of the drive rollers 16 .

Claims (8)

1. A method for wrapping a stack formed from a plurality of objects with stretchable film, wherein a film tube is removed from a film supply, opened and separated according to the height of the stack to be wrapped and closed to form a hood, the hood by a hood covering device with At least four reefing fingers that can be moved in the horizontal and vertical directions are taken over by engaging the reefing fingers by horizontally retracting into the four corner areas of the hood, then folding the bellows around the reefing fingers, then by horizontally extending the reefing fingers to a larger plan than of the stack horizontally pulled up and subsequently pulled over the stack and released from their wound position to rest against the stack, characterized in that for wrapping a stack with the same height, both enlarging and reducing cross-section The surfaces of the reefing fingers are moved horizontally during their vertical movement relative to the stack in adaptation to the contour of the stack, in such a way that the hood opening spanned by the reefing fingers reduces or increases and that the distance between the reefing fingers and the corner areas of the stack is approximately each is constant. 2. The method according to claim 1, characterized records that the distance of the reefers opposite the corner areas of the stack continuously wakes up and by horizontal movement of the ref finger is regulated. 3. The method according to claim 1 or 2, characterized records that before wrapping the stack the geometric dimensions of the same in one Control device of the hood covering device can be entered. 4. The method according to claim 3, characterized records that the input via a coding he follows that on at least one of the objects of the Stack or on a pallet-shaped base of the stack is attached. 5. The method according to claim 1 or one of the fol genden, characterized in that the foils hood during pulling on due to the Contour of the stack of horizontally retracted stel the fingers are stretched in the vertical direction becomes. 6. The method according to claim 1 or one of the fol genden, characterized in that the foils hood during pulling on due to the Contour of the stack of horizontally extended stel Relaxation of the finger in the vertical direction becomes. 7. The method according to claim 5 or 6, characterized ge indicates that the horizontal remains the same position of the reefing fingers alternate the foil hood stretched and relaxed selectively in the vertical direction becomes. 8. The method according to claim 5 or one of the fol genden, characterized in that the stretch the film hood in horizontal and / or ver tical direction measured and with a predetermined setpoint are compared and then ßend the stretch of the film hood in the vertical direction device is adjusted.