DEVICE FOR WRAPPING A STACK OF GOODS WITH A TUBULAR HOOD AND METHOD FOR CHANGING THE TUBULAR FILM STOCK IN AN APPROPRIATE DEVICE

Abstract

The present invention relates to a device for wrapping a piece item stack, which is formed of a plurality of piece item parts that are disposed on top of one another, with a tubular film, wherein the device has a tubular film stock, a conveyor device for pulling a predetermined length of tubular film out of the tubular film stock, a cutting device for cutting the pulled-off tubular film for the formation of a tubular hood and a fitting device, which is arranged downstream of the cutting device in the conveying direction of the tubular film, for pulling the tubular hood over the piece item stack, as well as a method for changing the tubular film stock in such a device. For enhanced safety and guarantee of a disturbance-free operation, a discharge device, which can discharge a length piece (L) of the tubular film, is proposed with the present invention as a part of the device for wrapping the piece item stack. In the method for changing the tubular film stock according to the invention, a lagging end of a consumed tubular film stock is connected to the leading end of a new tubular film stock, wherein the leading end and the lagging end are conveyed in the direction onto the cutting device in order to laterally discharge a length section (L) that bears the leading and the lagging end on top of an intake area for the piece item stack.

Claims

1. A device for wrapping of a piece item stack, which is formed of a plurality of piece item parts that are disposed on top of one another, with a tubular film, wherein the device has a tubular film stock, a conveyor device for pulling a predetermined length of tubular film out of the tubular film stock, a cutting device for cutting pulled-off tubular film for the formation of a tubular hood and a fitting device, which is positioned downstream of the cutting device in a conveying direction of the tubular film, for pulling the tubular hood over the piece item stack, comprising a discharge device for discharging a length section of the tubular film.

2. The device according to claim 1, wherein the discharge device is arranged downstream of the cutting device in the conveying direction of the tubular film.

3. The device according to claim 1, wherein the discharge device is disposed upstream of a spreading device for spreading the tubular film for the encroachment of the fitting device into the tubular film that is open on a bottom side in the conveying direction of the tubular film.

4. The device according to claim 3, wherein the discharge device is disposed between the cutting device and the spreading device.

5. The device according to claim 1, wherein the conveyor device has conveyor rollers that clamp the tubular film and that are disposed on top of the cutting device and that convey the tubular film in the conveying direction onto the cutting device.

6. The device according to claim 1, wherein the discharge device has a conveyor element that can be moved from a resting position into a discharge position in which the conveyor element is disposed in a gravitational field of the Earth below the cutting device so that the length section that is conveyed in the direction onto the fitting device comes in contact with the conveyor element.

7. The device according to claim 6, wherein the conveyor element has a continuously circulating conveyor element that is deflected around a return pulley on a discharge side that is disposed on a edge of a rack that frames a piece item stack to be wrapped.

8. A device for wrapping of a piece item stack, which is formed of a plurality of piece item parts that are disposed on top of one another, with a tubular film, wherein the device has a tubular film stock, a conveyor device for pulling a predetermined length of tubular film out of the tubular film stock, a cutting device for cutting the pulled-off tubular film for the formation of a tubular hood and a fitting device, which is positioned downstream of the cutting device in the conveying direction of the tubular film, for pulling the tubular hood over the piece item stack, further comprising a discharge device for discharging a length section of the tubular film, wherein the discharge device is arranged downstream of the cutting device in the conveying direction of the tubular film, wherein the discharge device is disposed upstream of a spreading device for spreading the tubular film for the encroachment of the fitting device into the tubular film that is open on the bottom side in the conveying direction of the tubular film, and wherein the discharge device has a conveyor element that can be moved from a resting position into a discharge position in which the conveyor element is disposed in the gravitational field of the Earth below the cutting device so that the length section that is conveyed in the direction onto the fitting device comes in contact with the conveyor element.

9. The device according to claim 8, wherein the conveyor element has a continuously circulating conveyor element that is deflected around a return pulley on the discharge side that is disposed on the edge of a rack that frames a piece item stack to be wrapped.

10. A method for changing tubular film stock in a device for wrapping of a piece item stack, which consists of a plurality of piece item parts that are arranged on top of one another, with a tubular hood, wherein the device has a tubular film stock, a conveyor device for pulling a predetermined length of tubular film out of the tubular film stock, a cutting device for cutting the pulled-off tubular film for the formation of a tubular hood and a fitting device, which is disposed downstream of the cutting device in the conveying direction of the tubular film, for pulling the tubular film over the piece item stack, wherein, while the tubular film stock is being changed, a lagging end of a consumed tubular film stock is connected to a leading end of a new tubular film stock and the leading end of the new tubular film stock is conveyed with the lagging end of the consumed tubular film stock in the direction onto the cutting device, wherein a length section (L) that bears the leading and the lagging end is discharged laterally above an intake area for the piece item stack.

11. The method according to claim 10, wherein the length section is cut off after the length section (L) has started to interact with a discharge device that triggers a discharge process.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Further details and advantages of the present invention can be derived from the following description of an embodiment in connection with the drawing. In this drawing, the Figures show:

[0016] FIG. 1 a side view of an embodiment;

[0017] FIG. 2 the Detail II indicated in FIG. 1 in an enlarged view in a resting position of the discharge device

[0018] FIG. 3 the Detail II according to FIG. 2 in a discharge position of the discharge device and

[0019] FIG. 4 a perspective top view of the discharge device of the displayed embodiment.

DETAILED DESCRIPTION

[0020] The embodiment of a device according to the invention shown in FIG. 1 comprises a rack 1 between whose vertical stands a lane 2 for intake and discharge of piece item stacks 3, which are formed respectively of a plurality of piece item parts in form of sacks that are arranged on top of one another or next to each other, is disposed. A roll 4, on which a tubular film 5 is wound up, is installed in a freely flexible way on the rack 1. The lateral edges of the tubular film 5 are inward-folded in the wound up state. Subsequently, the used film is a satchel sleeve 5. The tubular film 5 is fed into a conveyor device, which is formed by two conveyor rollers 7, 8, via return pulleys 6, wherein the conveyor roller marked with reference sign 7 is engine-driven and the tubular film is clamped between the conveyor roller 7 and the conveyor roller 8. Underneath this conveyor device 7, 8 there is a cutting device 9 that is suitable to separate the tubular film material that hangs down from the conveyor rollers 7, 8. In the conveyor device behind this cutting device 9, there is a welding device 10 with sealing jaws that can be moved towards one another that is provided upstream of a spreading device 11 in the conveying direction of the tubular film 5 and hence in the gravitational field of the Earth. The spreading device 11 has suction boxes that can be moved on rails, that hold the material of the tubular film 5 through negative pressure and that can be moved longitudinally and/or transversally to one another in order to open the satchel sleeve for the encroachment of a fitting device 12 into the tubular film 5 (cf. DE 20 2014 102 841 U1).

[0021] The fitting device 12 comprises gripping fingers 13 that can be moved synchronously, i.e. vertically, in the upward direction of the vertical stands and that can encroach in the opened tubular film. The gripping fingers 13 can also be moved horizontally towards one another and/or away from one another to encroach on one hand et first into the tubular film 5 that is opened at the bottom side and to subsequently stretch said tubular film into a dimension that is larger than the base area of the piece item stack 3. In this process, the tubular film 5 can be stretched elastically as known from the EP 1 013 549 A1 of the applicant. The structure of a device for wrapping a piece item stack described before is essentially prescribed and explained in the EP 2 719 628 B1 and/or the EP 2 336 033 B1 or the DE 10 2013 019 576 B4 or rather the DE 1 938 960 C1.

[0022] As in the state of the art mentioned before, the gripping fingers 13 are respectively associated with drive rolls 14 that clamp the tubular film material between themselves and the gripping fingers 13 after encroachment of the spreading fingers 13 into the tubular film 4 and that can hit the gripping fingers 13 by means of a drive. During lowering of the individual gripping fingers 13 along the piece item stack 3 and in the upward direction of said piece item stack, the tubular film 5 reefed this way is removed and/or pulled off from the gripping fingers 13 and laid against the piece item stack 3. Prior to this, a tubular hood, which is closed on the upper side and whose lid fits tight against the upper side of the piece item stack 3 while the gripping fingers 13 are being lowered and therefore constitutes an opposing resistance that ensures that the films will be pulled off from the gripping fingers 13, is usually formed by means of actuating the cutting device 9 and the welding device 10. Hence, the drive rolls 14 do not necessarily have to be operated contrarily to the reefing direction during fitting in order to discharge the material of the tubular film 5 away from the gripping fingers 13.

[0023] FIGS. 2 and 3 illustrate the discharge device, which is marked with reference sign 20, in the displayed embodiment. The discharge device 20 has a circulating conveyor belt 21, which circulates around a return pulley 22 on the discharge side and a return pulley 23 on the drop-off side. The return pulley 22 on the discharge side can be moved translationally and transversally, i.e. in a horizontal direction. FIG. 2 shows the return pulley 22 on the discharge side in its resting position. FIG. 3 illustrates the return pulley 22 on the discharge side in its discharge position in which the conveyor belt 21 is provided in the gravitational field of the Earth directly underneath the conveyor device 7, 8 and/or the cutting device 9 and/or the sealing jaws 10 so that a length section of the tubular film 5, which is discharged away from the conveyor device 7, 8, arrives directly on the conveyor belt 21. The conveyor belt 21 subsequently diverts the path of the tubular film 5 in the deflecting position according to FIG. 3 from the conveyor device 7, 8 to the intake area for the piece item stack 3 that is defined within the rack 1. To compensate the varying length through movement of the return pulley 22 on the discharge side from the resting position into the discharge position, a second flexible return pulley, which is not displayed in detail and which is held under preload and around which the conveyor belt 21 circulates, is provided.

[0024] The return pulley 23 on the drop-off side is located at the edge of the rack 1 so that the discharge path formed on the upper side of the conveyor belt 21 ends outside of the rack 1.

[0025] Guiding systems for the suction boxes of the spreading device 11 are formed under the conveyor belt 21. Accordingly, the discharge device is located between the welding device 10 and the spreading device 11.

[0026] FIG. 4 illustrates the details of the discharge device. As can be seen, the conveyor belt 21 comprises four strands that are stretched in parallel and that are guided over rolls that are equipped with grooves for the intake of the strands. In this context, FIG. 4 shows the discharge device in the resting position in which the sliding frame 25, which holds the return pulley 22 on the discharge side and an upper return pulley 24, covers the holding frame 26 that is located underneath to a considerable extent. On its end on the discharge side, the holding frame 26 carries a drive shaft 27 for the strands of the conveyor belt 21. This drive shaft 27 is coupled with a drive 29 in an actuated way via a chain 28. The holding frame 26 also carries the return pulley on the discharge side. The sliding frame 25 carries an inner return pulley 30 as well as the directly adjacent upper return pulley 24, which, however, is disposed slightly above said inner return pulley in the vertical position. The conveyor belt 21 circulates around all rolls 22, 23, 24, 30 and the drive shaft 27 with the pertaining drive wheels 31 for the respective strands of the conveyor belt 21.

[0027] On the outer side of the holding frame 26, support cylinders 32 are provided, which can displace the sliding frame 25 in relation to the holding frame 26 in order to move the sliding frame 25 from the resting position shown in FIGS. 2 and 4 into the discharge position shown in FIG. 3. During this sliding movement, the conveyor belt 21 remains stretched due to the deflection of said conveyor belt over the inner return pulley 30 that is attached to the sliding frame 25. This is because the space increase due to retraction of the sliding frame 25 in the direction onto the discharge position between the return pulley 22 on the discharge side and the return pulley on the drop-off side 23 is equivalent to the reduction of the length between the drive shaft 27 and the inner return pulley 30.

[0028] During usual operation of the device for wrapping a stack of goods, the return pulley 22 on the discharge side is in the resting position according to FIG. 2. If the tubular film material of the roll 4 is consumed as part of a wrapping process, a further roll will be fastened on the rack 1. In this process, the further roll can be disposed at the position at which the previous roll 4 was arranged previously. Alternatively, the rack can also have a second holding device for the further following roll. The lagging end of the film, which is provided on the inside of the roll 4, is connected to the leading uncovered end of the further roll after consumption of the roll 4. Afterwards, the conveyor device 7, 8 is operated in order to covey the film material of the tubular film 5 and to dispose said film material past the return pulleys 6 and the two conveyor rollers 7, 8 above the intake area. The length area L that is useless for wrapping of a stack of goods due to the connection point between the leading and the lagging edge is discharged in the process. For this, the length area L is cut free through actuation of the cutting device 9 on its front end as part of the wrapping process of the last piece item stack 2 with the old film material. Subsequently, the conveyor belt 21 is set to the discharge position. The conveyor rollers 7, 8 are operated so that the length section L that is hanging down is conveyed onto the conveyor belt 21 that is driven in a circular way. The length section L is thereby deflected by the moved conveyor belt 21 in an essentially horizontal position and conveyed up to the return pulley on the drop-off side. As part of this horizontal deflection and conveying process, the length section L is cut off on its other end, whereby an uncovered end of the new film material is cut free behind the conveyor rollers 7, 8. The useless length section L is dropped off through further conveying of the conveyor belt 21. It falls off outside of the rack 1 and can, where appropriate, arrive at a collecting tank via a slide. Then, a predetermined length of tubular film for the formation of a tubular hood is pulled off from the tubular film stock in the usual way by means of propulsion of the conveyor rollers 7, 8, separated and welded and pulled over the piece item stack in a way that is known in principle.

REFERENCE SIGN LIST

[0029] 1 Rack [0030] 2 Lane [0031] 3 Piece item stack [0032] 4 Roll [0033] 5 Tubular film [0034] 6 Return pulley [0035] 7 Conveyor roller [0036] 8 Conveyer roller [0037] 9 Cutting device [0038] 10 Welding device [0039] 11 Spreading device [0040] 12 Fitting device [0041] 13 Gripping finger [0042] 14 Drive roller [0043] 20 Discharge device [0044] 21 Conveyor belt [0045] 22 Return pulley on the discharge side [0046] 23 Return pulley on the drop-off side [0047] 24 Upper return pulley [0048] 25 Sliding frame [0049] 26 Holding frame [0050] 27 Drive shaft [0051] 28 Chain [0052] 29 Drive [0053] 30 Inner return pulley [0054] 31 Drive wheel [0055] 32 Positioning cylinder [0056] L Length area