EP1050459A2 - Method and device for wrapping an object with a thermoplastic film - Google Patents

Abstract

A closer (5), movably mounted on a rail (50), has its position monitored by a positioner (6) unit. Depending on the position the closer, a control controls a clamp (40) in order to prevent the plastic sheeting (20) from tearing and or the contents (1) f shifting position. The contents are enclosed on one or more sides by a sheet and stay between two lengths (21,22) of sheeting. T closer positions the two sheets so that they are welded by a sealing unit (8); the two cut ends of the middle sheeting part are welded.

Description

The invention relates to a method and an apparatus for Wrapping a good with a plastic film, the Driving in or out of the film well against a film curtain is enclosed on several sides and in the import area next to the goods a first and a second film curtain part remains and a intermediate film middle part of the goods on one or more sides encloses. A closer is provided, which the Afterwards, the import area is at least almost completely closed, wherein at least one of the two film curtain parts by one Clamping device is tensioned so that the thing lying around Foil middle part fits tightly. The closer positions here the two film curtain parts such that these by a Sealing unit to be welded together and each severed ends of the film middle part welded together to then hand out the finished goods.

The aforementioned methods and devices are used, for example previously grouped goods, for example with a plastic skin film to connect firmly to one another to make bigger solid unit of goods.

For example, a stack of boxes is piled up that by the above-described method and the device be firmly connected, if so Individual boxes are required to separate the plastic film is.

In known methods and devices for Example a film roll above and below the Surface of the goods. These two slides are together welded and thus form the foil curtain against which the Is well promoted. Through the conveying movement of the goods a film middle part around the goods and divides the film curtain in a first and a second film curtain part, which remain firmly connected. With the known A hold-down device is then moved to the estate in order a slipping of the goods or that of different individuals Avoid packs of existing pile of goods. The closer which ultimately interacts with the sealing unit becomes Example pneumatically controlled closed, while still Pulled off the film material from the film roll or the film supply becomes.

To the film and in particular the film middle part, which around the good is looped to be as tight as possible at the state of the art as soon as the closer enters the import area has closed, used a clamping device in front of one Welding the film to the goods tightens them. It becomes Example two oppositely driven rollers are used, each roller being provided for a film curtain part. The film material is transported back by the opposite movement and thus tightened or stretched the film. After the film middle part lies tightly against the good, the Sealing unit used, on the one hand the foil curtain severed, the ends of the film middle part welded together and at the same time or shortly afterwards the two, well separate foil curtain parts reconnects in order for that next following good again a closed film curtain To make available.

The number of cycles of the known devices and those equipped with them The process is determined by the individual periods, which is the sequential sequence of the aforementioned packaging steps required.

To the performance of such methods and devices the number of cycles, i.e. the number of goods, correspondingly per unit of time with a plastic film be taken to increase. An increase in movement the good is not always usable, because the good, for example consists of stacked boxes or the like and too great accelerations to slip this Stacking or even toppling over, inevitably leads to a failure of the machine.

The invention has for its object a method and to improve a device as described at the beginning, that the number of cycles with constant reliability is increased, thereby increasing the performance of the aforementioned devices or to increase procedures.

To achieve this object, the invention is based on one Method and an apparatus as described in the introduction and proposes that a clamping means as a clamping means on the closer is provided for the first film curtain part and that Clamping means at least during the closing movement of the closer for part of the closing movement, the first film curtain part or the film middle part clamps and so taut.

The configuration according to the invention ensures that the otherwise the usual sequential sequence of packaging steps runs at least partially simultaneously to accelerate of the packaging process, but without doing so impress additional forces on the goods or the stack of goods, which may lead to an undesired slipping or Would cause the goods or the stack of goods to fall over.

As a clamping device for the first part of the film curtain a clamping means is provided which is movable with the closer is arranged. The closer who, while the good against the The film curtain moves as far up, so that Can drive through well, then closes the previously released one Import area. The state of the art afterwards The clamping process is now at least partially in the Integrated closing movement, which creates a time advantage. At the same time, the movement of the closer is part of the Of the clamping process. By folding the invention of these two activities it is possible to change the number of cycles increase about 20 to 40%.

In a preferred embodiment of the invention, that a hold-down device holds the material in place before the film middle part by tensioning one or both of the foil curtain parts is excited. This ensures that the good, while the film middle part wraps around the good, does not slip or fall over.

Furthermore, it is proposed that during the tensioning of the first film curtain part also the second film curtain part is excited. By simultaneously executing the clamping process another time advantage is achieved. It is natural also possible, the clamping sequentially one after the other to expire. It is also possible to use the hold-down device continue to have an impact on the property, in particular pulling one of the top or bottom packs away Avoid multiple packs of existing stacks of goods.

The invention also relates to an impact device of a good with a plastic film, which in particular is suitable for carrying out the aforementioned method. According to the invention it is proposed that the Closer is movably mounted on a rail guide and a positioning unit is provided which the position of the NO contact monitors and controls, depending on the Position of the closer, which controls the clamping means to a Tearing the film curtain and / or slipping of the To avoid good things. The conditions that are met must be safe and reliable with a good as described to enclose the plastic film are relatively narrow dimensioned. It is usually possible to use the ones described above Devices not just a format of goods or stacks of goods to wrap; but they are also for different formats applicable. This also changes the conditions, in particular the necessary stroke distances of the NO contact and thus interacting clamping means, which at the same time tightening of the film material results. Through the use according to the invention a positioning unit that monitors the movement of the closer, it is possible on the relatively narrow To make room for conditions to ensure that that on the one hand the film curtain is not unintentionally is torn or such a great force on the good is exercised, which cause the goods to slip would. The respective conditions, in which clamping the clamping means during the closing movement of the closer acts on the first part of the film curtain, for example due to determined by experiments or there are empirical values for this available, which results in particular from the stretching behavior allow the plastic film used to be derived.

In a further development according to the invention, that a servo motor serves as the positioning unit, which has a Drive means, for example a toothed belt or a drive spindle, on the slider-like closer works. The positioning unit performs two functions. On the one hand, a motion drive is provided, on the other hand enables the positioning unit to read out the exact Position of the element driven by the positioning unit, here the closer. The use of a servo motor allows the realization of the above two functions. The servo motor is capable of being relatively high Accelerate to run in the short time segments perform the desired movements. The connection of the Servomotors with a drive means, for example a toothed belt or a drive spindle with the sled-like Closer results in a safe transmission of the closing movement from the servo motor to the slide on the one hand and at the same time a high level of security when determining the position the closer. According to the invention it is provided that the clamping means may not be along the entire length Movement path of the closer the first film curtain part stuck, but only after a certain, just of additional Conditions dependent path is used. This exact path monitoring is with the positioning unit proposed according to the invention possible and will be controlled accordingly monitors the when the corresponding position is reached Clamping device actuated.

According to the invention it is also proposed that on the rail guide, on which the closer is already arranged like a sledge is also the hold-down device and / or the sealing unit is arranged.

The further development according to the invention makes it possible to to create a modular unit, in which all moving elements, the closer, the hold-down and also the sealing unit are arranged. This makes it easier Maintenance, because in the case of maintenance, for example, this complete Unit removed and held by an appropriate one Exchange unit is replaced in any case Ensure continued operation of the machine, then in the dismantled Condition on the one hand the hold-down device or the sealing unit or to check the closer. Allowed at the same time the proposed summary of various assemblies in one unit easier adjustment and adjustment of the Parameters, since these are no longer separate on their own guideways must be aligned.

In a preferred embodiment of the invention, that the clamping means is arranged on the closer and moving with it. Alternatively, it is possible that a device is selected in which the clamping means is fixed and the closing movement of the closer Tightening the film around the well results. Please note doing that the load on the film at a fixed Clamping means is higher and the control correspondingly more precise must be switched.

Fig. 1 bis Fig. 4

in einer Seitenansicht den Ablauf des erfindungsgemäßen Verfahrens in einer erfindungsgemäßen Vorrichtung.

The invention is shown schematically in the drawing. Show it:

1 to 4

in a side view the sequence of the method according to the invention in a device according to the invention.

The good 1 lies on a support 11 and is along the Direction of conveyance 10, for example, from a grouper or the like transported up. The good 1 exists here Example from one piece or several pieces, for example are arranged one above the other and next to each other and so for Example form a pile of goods or a stack of goods. The Gut 1 becomes promoted in the import area 12 against a film curtain 20.

The film curtain 20, better shown for example in FIG. 4, extends essentially transversely to the conveying direction 10 in Entry area 12. The film curtain 20 is formed here made of two foils welded in the middle area, which on the Foil rolls 29, 29 'are provided. In the one shown here Exemplary embodiment, the film rolls 29, 29 'are located above (Film roll 29) and below (film roll 29 ') the support 11. But it is also possible in the same way Film roll 29, 29 'or the film supply 28, 28' on the side, to be arranged to the left and right of the conveyor path 10 of the goods 1, to implement the proposal according to the invention.

The film 2, 2 'is held on the film roll 29, 29' and meandering through a film supply 28, 28 ' carried out in the short term with the rapid packaging movement to allow sufficient film material run-on. For this purpose, the film supply 28 is pivotally mounted and made possible so the quick removal of short pieces of film, without the great inertia of the heavy film rolls 29, 29 ' to have to accelerate. For an even pulling movement of the Film 2 from the film roll 29, 29 'is an unspecified one Driving wheel drive provided.

The good 1 to be packaged in FIG. 1 consists essentially of a cuboid body. The first (in conveying direction 10) Side surface 13 of the good 1 touches the film curtain first 20, which is also transported in the conveying direction 10. The film 2 begins around the side surface 13 and around the To lay roof and floor surface 14, 15 and folds the film curtain 20 literally. The folding area of the Film curtain 20 now forms the film middle part 23, which the film curtain 20 further into a first Foil curtain part 21 and a second foil curtain part 22 divided.

The embodiment shown in FIG. 1 is located here the first film curtain part 21 substantially above and the second film curtain part 22 and substantially below the Contact surface 11.

1 to 4, the packaging process for a Well shown 1. It is clear that there are 11 more on the edition Goods are transported to and from here, for the sake of clarity are not shown.

Due to the conveying movement of the goods 1 into the film curtain 20, film material 2 is drawn off from the film supply 28, 28 ', this is due to the pivoting movement 27, 27 'of the film supply 28, 28 'indicated.

The for packing or enclosing the goods 1 with a film 2 additional necessary elements, such as the The closer 5, the hold-down 7 and the sealing unit 8 are located a common rail guide 50, which is in the extends substantially at right angles to the conveying direction 10. According to the invention, these elements can also be stored individually his.

In Fig. 2 it is shown that in cross section essentially square good 1 on three of the four side surfaces, in particular on the roof surface 14, floor surface 15 and a first side surface 13, is already surrounded by the film material 2. The Edition 11, which is designed for example as a movable conveyor belt is, can be controlled intermittently, in which no sequence in the direction of conveyance 10 he follows. On the other hand, in the position shown here Hold-down device 7, which is designed like a stamp, through the Working cylinder 70, for example pneumatic or electric is driven from above against the good 1 to hold the good 1 with the underlying film middle part 23. The closer 5 is still in an open position Position. The holding movement of the hold-down 7 against that Good 1 is indicated by arrow 72.

The hold-down 7 is here above the closer 5 also on the rail guide 50, but the Hold-down 7 due to the separately provided working cylinder 70 can do against the good. In a variant of the The invention provides that the positioning of the hold-down device 7 by the positioning unit provided for the closer 5 6 is possible. This is the fixation of the hold-down 7 on its slide part 71, on which the hold-down device 7 is mounted on the rail guide, solved and then the positioning unit 6 is controlled such that the closer 5 shows the slide part 71 in accordance with a new format Good 1 repositioned. Then the slide part 71 fixed again. For example, this can be done automatically with a pneumatic or electro-magnetic latches happen or done manually. By such an inventive Further development, it is also possible to hold down 7 position the goods 1 automatically. This saves set-up times when changing formats reached.

Good 1 is almost complete of film material, at least but enclosed on three sides. Of course it is possible to a good 1 with the device according to the invention pack that has fewer side surfaces.

In Fig. 3 it is indicated that the film middle part 23 by the activated clamping device 4 is tensioned and tightened so this applies as closely as possible to the good 1.

The tensioning means 4 for the film 2 are for the first film curtain part 21 a clamping means 40 on the closer 5 and for the second film curtain part 22 is a slotted roller 41 intended.

First, the clamping means 40 is actuated. This is through the Arrow 42 indicated by which the clamping means 40, which is formed like a strip, against the first film curtain part 21 is employed. Depending on the position of the closer 5, this movement of the clamping means 40 is controlled. It is it should be noted that on the one hand the clamping means 40 are not closed controlled early with respect to the closing movement 51 of the closer 5 is not so in particular the film middle part 23 very tense that this tears, on the other hand it must not controlled too late, otherwise the tightening would be too low of the film middle part 23 and thus no tight fitting Foil packaging 3 on the good 1 is reached. The clamp movement 42 is monitored by a controller Provided drive depending on the position of the Closer 5, which is monitored by the positioning unit 6 is controlled. By clamping the film part 21 and the closing movement 51 of the closer 5 becomes one tries to pull further film material from the film roll 29. At the same time, however, the film middle part 23 tightened by the downward movement, this also with the hold-down device 7 that only ensures that that the good 1 remains in shape, for example one above the other Do not shift the stacked boxes laterally.

This sequence shows that the closing movement of the Closer at the same time as tensioning or tightening of the film middle part 23 around the good 1 and for a tight fit of the film 2 on the good 1 ensures. This will in the packaging sequence it saves time allowed the packaging cycle with higher clock speed to let go. This will improve the performance of such a device, or machine or such a method elevated.

Simultaneously with the clamping of the clamping means 40 Roller 41 rotated about its longitudinal axis. The roller 41 is slit lengthways, through this slot 43 the second, lower Foil curtain part 22 is performed. By the rotation 44 (clockwise) will be the one in the area of Bottom surface 15 arranged film middle part 23 pulled tight, where, on the other hand, the clamping means 40 pulls the film material tight effected in the area of the roof surface 14.

The clamping means or clamping means 4, 40, 41 Forced forces in the film are advantageously essentially the same size for an even tightening of the to reach the rear part on the side surface 13 of the good 1 and not to deform the good 1.

During or after the lowering movement 51 of the closer 5 the working cylinder 70 of the hold-down 7 reversed, and the Hold-down device 7 upwards, according to arrow 73, from the good 1 lifted.

The closing movement 51 of the closer 5 is here by the Positioning unit 6 causes. The positioning unit 6 exists here from a drive, for example a servo motor 60 and a drive means 61, here for example one endless revolving toothed belt, which via the terminal block 62 with the NO 5, the sled-like on the rail guide 50th sits, is connected. The positioning unit 6 also determines at the same time the position of the NO 5. The control monitors both the function of the positioning unit 6, such as also the clamping or clamping movement of the clamping means 4, clamping means 40 or roller 41.

The roller 41 is advantageously essentially in cross section formed round to have an excessive notch effect avoid the slide 2 if possible. Here are also on the slotted ends of the provided edges of the roller 41 for Example, bevelled in order to 44 during a clamping movement not to accidentally cut the film 2.

In Fig. 4 the last packaging sequence is shown. The Sealing unit 8, which is also on the rail guide, for example 50 is stored, runs from below, along the arrow 80, upwards, against the now overlapping foil curtain parts 21, 22. The formation of the sealing unit is here known and designed such that, for example, in a common Sealing process on the one hand the good 1 with the now separated Foil middle part 23 for a finished foil packaging 3 is welded and on the other hand the one initially cut Foil curtain 20 is reassembled and welded to for the next good as packaging material, as described, to be available again.

During the movement of the sealing unit 8, the clamping means 40 opened (see arrow 45), as well as the tension effect of the Roller 41 by turning in the direction of arrow 46 (against the Clockwise direction) solved.

The good 1 is enclosed with a film packaging 3 on four sides and is transported to the outside on the pad 11.

The claims now filed with the application and later are attempts to formulate without prejudice to achieve further protection.

The backward relationships mentioned in the dependent claims point to the further training of the subject of the main claim by the features of the respective subclaim there. However, these are not considered a waiver of achievement an independent, objective protection for the characteristics to understand the related subclaims.

Features previously only disclosed in the description can in the course of the process as of essential to the invention Significance, for example to differentiate it from the prior art be claimed.

Claims (9)

Process for wrapping a good with a plastic film, the good being enclosed on one or more sides by the film while driving against a film curtain and in the import area next to the good a first and a second film curtain part and an intermediate film middle part enclosing the good on one or more sides and a closer then at least almost completely closes the import area, at least one of the two film curtain parts being tensioned by a tensioning device, so that the film central part lying around the goods fits tightly and the closer positions the two film curtain parts so that they are welded together by a sealing unit and the each severed ends of the film middle part are welded to one another in order to then output the finished wrapped goods, characterized in that a clamping means is provided on the closer as a clamping means for the first film curtain part and the clamp with tel during the closing movement of the closer, the first film curtain part or the film middle part clamps at least for part of the closing movement and thus tensions. A method according to claim 1 , characterized in that a holding-down device holds the material in place before the film middle part is tensioned by tensioning one or both of the film curtain parts. Method according to one or both of the preceding claims , characterized in that the second film curtain part is also tensioned during the tensioning of the first film curtain part. Device for wrapping a good with a plastic film, in particular for carrying out a method according to one or more of the preceding claims, characterized in that the closer (5) is movably mounted on a rail guide (50) and a positioning unit (6) is provided which monitors the position of the closer (5) and controls, depending on the position of the closer (5), the clamping means (40) so as to avoid tearing of the film curtain (20) and / or slipping of the goods (1) . Apparatus according to claim 4, characterized in that a servo motor (60) serves as the positioning unit (6) and acts on the slide-type closer (5) via a drive means (61), for example a toothed belt or a drive spindle. Device according to one or both of claims 4 and 5, characterized in that the hold-down device (7) and / or the sealing unit (8) is / are also arranged on the rail guide (50). Device according to one or more of claims 4 to 6, characterized in that a slotted roller (41, 43) is provided as the tensioning means (4) for the second film curtain part (22), which roller about its longitudinal axis for tensioning the second film curtain part (22) is pivotable. Device according to one or more of claims 4 to 7, characterized in that the clamping means (40) is arranged on the closer (5) and moves with it. Device according to one or more of claims 4 to 8 , characterized in that the position of the hold-down device (7) on the rail guide (50) can be adjusted by the positioning unit (6) and the closer (5).

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