EP0916579A1 - Plastic bags opening device - Google Patents

Abstract

The pneumatic opening device has at least one suction cup(18) which is installed on an opening head(16) movable perpendicularly to the contact face(14a) and serves for initial lifting of the second bag wall(3). A gripper(19) is installed on the suction head and pivots around an axis (20) running parallel to the opening edge, and after initial lifting of the second wall is pressed against its inner side so that the second wall is clamped between the gripper and suction head.

Description

The invention relates to a device for opening plastic bags, the scaly on top of each other on at least two at a distance from each other and The straps that run vertically to the opening edge of the pouches are detachably glued are, with a substantially horizontal feed path along which the Plastic bag of an opening station by pulling the straps gradually can be supplied with a contact surface provided at the opening station which the opening-side area of the first bag wall through the tensioned Carrying straps is held and fixed, with a pneumatic opening device, by means of which the opposite second bag wall from the first bag wall can be lifted off to open the bag, and with a roller conveyor for removal filled bag from the opening station, as well as with a subsequent to the Opening station arranged winding device for winding the of the Plastic bags detached carrier tapes.

In such a device known from DE 40 08 402 A1 for opening Plastic bags are the plastic bags lying on top of each other in scales gradually over the roller conveyor and pulled a table adjoining this and arranged at the opening station. The table forms a continuous contact surface (support surface) for the Plastic bag. A stock of plastic bags is in a box below the table. The pouch is transported step by step by the wrapping device, with which the straps drawn over the front edge of the table are wound up become. If the foremost and uppermost bags have a sensor arranged on the table reached, the winding device is stopped and by means of several air nozzles where air flows out, the bag is opened. This will be the first one below Bag wall held by the straps on the table's abutment surface while the second, top wall of the bag is lifted by the air currents and thus the Bag is opened. After opening the bag, a funnel-shaped barge is put in moved the inflated foremost pouch and a cylinder presses the contents, e.g. a piece of cheese, through the barge into the bag. The frontmost, filled bag detached from the carrying belts and transported away via the roller conveyor. Opening the However, plastic bags using blown air flows are not particularly reliable and it is only works with bags that are powdered and facing each other Do not stick the bag walls together as a result of the powdering. In powdered Plastic bags adhere to the mutually facing inner sides of the two bag walls, also due to static charge, so strongly against each other that a reliable Opening with blown air flows is not guaranteed. Not open or only partially open Bags lead to malfunctions that cause business interruption and also also require an operator to troubleshoot problems. Becomes a bag not fully opened, then the piece of cheese is placed over the on the table and the Bags lying on the roller conveyor are pushed and these become dirty. Similar thing happens when parts of the filling material reach the table. These are from the each filled bag pushed over the lying on the roller conveyor and pollute this. There is also a risk that when moving a filled bags over unfilled bags, these are torn off the carrying straps, which also leads to interference. Another disadvantage is that the blown air flows Bacteria and other contaminants can get into the opened bag. The bags stored in a box under the table can also be used falling product pieces and other foreign matter are contaminated.

From US-A-3 331 182 a device for opening scale-like is Plastic bags lying one above the other are known, in which the bags are opened a suction cup is provided. The bags are essentially along one vertical guideway from bottom to top. At the opening station the horizontally displaceable suction cup on the bag wall facing away from the carrying straps top bag, then this bag wall from the first bag wall to take off.

From US-A-5 421 143 a device for opening bags is known, a gripper is arranged on an opening head, which is parallel to the Opening edge of the axis of the bag is pivoted on the opening head and after the initial lifting of the second bag wall on the inside like this can be pressed that the second bag wall is clamped between the gripper and suction cup becomes. However, this opening device is for special, vertically arranged bags provided, of which several are combined to form a block. The top ends of a bag wall, similar to the leaves of one Tear-off calendar, held in a holder, being between the upper ends of the one bag wall and the rest of the same, a perforation is provided is. The second wall of the bag only extends to the level of the perforation. This the known device therefore requires certain bags combined in blocks, their manufacture is expensive.

The invention is therefore based on the object of a device for opening To create plastic bags of the type mentioned that are reliable and works trouble-free, and in particular a reliable opening of non-powdered and possibly electrostatically charged plastic bags of all kinds and there is also no risk of contamination for the bags.

This is achieved according to the invention in that the feed path is at a distance Arranged above the roller conveyor and a cross rail at the end of the infeed conveyor is provided, the underside of which forms the contact surface that the pneumatic Opening device comprises at least one suction cup, which on a vertical to the contact surface vertically movable opening head is arranged from below the contact surface is too movable and the second one is initially lifted off Bag wall is used, and that a gripper is arranged on the opening head, which around an axis running parallel to the crossbar is pivotally mounted on the opening head and after the initial lifting of the second bag wall on the inside so can be pressed that the second bag wall is clamped between the gripper and suction cup becomes.

The invention is therefore based on the idea that the feed path for the Arrange plastic bags at a distance above the roller conveyor. This has the significant advantage that what the bags when not fully opening a bag should hardly occur in the device according to the invention, no longer by Moving the contents, e.g. Cheese that can be contaminated as it is above the Roller conveyor are arranged. Even empty bags cannot fall through Fill pieces or other foreign matter are contaminated. You stay in Clean the area around the opening station so that there are no faults on the suction cup can. In addition, filled bags are only ever on the roller conveyor transported away and do not have to, as in the known known Only move the device over unfilled bags. This is another Source of interference avoided. The respective plastic bag is opened by the interaction of one or more suction cups with a mechanical gripper. As practice has shown, the interaction of suction cup and Grippers powder-free and also statically charged plastic bags of any kind, see above e.g. Tubular bags, sealed edge bags, shrink bags and the like with the largest Reliability and trouble-free opening. The opening of the pouch is because the second bag wall is pulled down from the cross rail by suction cup, favored by gravity. By working in addition to the suction cup Gripper, which lies against the inside of the second bag wall and the second Bag wall presses on the suction cup made of rubber-elastic material, considerable tensile forces can be exerted on the bag wall, so that reliable it is prevented that the bag wall unintentionally from the opening head when opening solves. Opening can also be accelerated. Since opening the bag without Blowing air flows, no bacteria or other contaminants can occur in the bag be blown.

Advantageous embodiments of the invention are in the subclaims featured.

Figur 1 eine Seitenansicht der Vorrichtung,

Figur 2 eine Draufsicht in Richtung II der Figur 1,

Figur 3 einen Teillängsschnitt der Vorrichtung,

Figur 4 einen Querschnitt nach der Linie IV-IV der Figur 3,

Figur 5 einen Teillängsschnitt in einem vergrößerten Maßstab,

Figur 6 eine Teilseitenansicht eines zweiten Ausführungsbeispieles,

Figur 7 eine Draufsicht in Richtung VII der Figur 6,

Figur 8 eine Teilansicht in Richtung VIII der Figur 6.

The invention is explained in more detail below with reference to exemplary embodiments shown in the drawing. Show it:

FIG. 1 shows a side view of the device,

FIG. 2 shows a plan view in the direction II of FIG. 1,

FIG. 3 shows a partial longitudinal section of the device,

FIG. 4 shows a cross section along the line IV-IV in FIG. 3,

FIG. 5 shows a partial longitudinal section on an enlarged scale,

FIG. 6 shows a partial side view of a second exemplary embodiment,

FIG. 7 shows a plan view in the direction VII of FIG. 6,

8 shows a partial view in the direction VIII of FIG. 6.

The plastic bags 1 are rectangular in the flat state. Lie flat in each case two plastic films, subsequently as the first bag wall 2 and second Bag wall 3 referred to each other, which are interconnected at three edges. At the fourth, front edge, which is referred to as the bag edge 2a or 3a, are the the two plastic films are not connected. Along this edge of the bag 2a, 3a the frontmost plastic bag should be opened. The plastic bags 1 are manufactured as a so-called chain bag. There is a series of plastic bags 1 scaly on top of each other. The bags 1 are on two at a distance from each other and perpendicular to the opening edge 2a, 2b of the bag 1 extending support straps 4 detachable glued on. In the advantageous embodiment shown the device, the bags 1 of the opening station 5 fed horizontally so that the Tragbändar 4 are above and thus to the top glued outside of the first bag wall 2 glued are. The distance between the opening edges 2a, 3a of two successive, scale-like one above the other For example, component 1 is approximately 40 mm. Each bag 1 is only in this area of approximately 40 mm connected to the two straps 4.

The bags 1 fixed on the carrying tapes are useful on a cylindrical core 6 to form a roll 7 wrapped on. The core 6 is supported by an axis 8, which engages in the core 6 in a rotationally fixed manner. The Axis 8 can be suspended in a holder 9. The axis 8 and so that the roller 7 can be braked.

The wound on the roll 7 bags 1 are from the roll 7 is withdrawn and the feed path 11 of the Opening station fed. This is done using a provided after the opening station 5 Winding device 1,2 by a not shown Stepper motor is driven. The winding device 12 is used to wind up the plastic bags 1 detached carrying straps 4. The gradual further transport the plastic bag 1 is thus carried out by means of the Winding device 12, which sections of the carrier tapes 4 winds up so that a train on the tapes 4 exercises and tensions. The tension of the straps 4 can be influenced by the braking device 10.

The feed path 11 is advantageously by two in the horizontal direction of movement B of the plastic bag 1 extending angular rails 13 formed in Distance of the bag width b are arranged from each other. The plastic bags 1 lie with their longitudinal edges on the horizontal angle legs 13a the angle rails 13 on. Their mutual Distance is according to the respective bag width b adjustable.

A transverse rail 14 is provided at the opening station 5, whose underside 14a is a contact surface for the two straps 4 and also for the one above forms first building wall 2. Through the winding device 12 are solved by the Beutein 1 and over the Deflection rollers 15 guided straps tensioned and in System held on the contact surface 14a.

Below and opposite the contact surface 14a an opening head 16 vertically movable arranged. The vertical lifting movement of the opening head 16 is effected by a piston-cylinder unit 17. The opening head 16 carries at least one upwards directed suction head 18, the bottom of the Contact surface 14a is too movable. On the opening head 16 a gripper 19 is also arranged, which by a parallel to the opening edge 2a, 3a or also parallel to Cross rail 14 axis pivotable on the opening head 16 is stored. Serves to drive the gripper 19 a piston-cylinder unit supported on the opening head 16 21.

The gripper 19 is angular in side view and has a terminal block 19a which of at the top of the rubber-elastic material Suction cup 18 can be pressed.

The suction cup 18 is opposite to that in the open position the foremost pouch in the immediate vicinity the opening edge 2a, 3a arranged the same as it can be seen from Figure 5.

Opposite the opening station 5 is a horizontal and thus slide 22 that can be moved in the longitudinal direction of the bag arranged by a piston-cylinder unit 23rd is drivable. The carriage 22 has a horizontal Support surface 24 for the filling material, e.g. a piece of cheese, on. At the end of the opening station 5 facing Carriage 22 two spreading sheets 25 are arranged. The levels of these two spreading plates extend essentially in the direction of displacement C of the slide 22nd and perpendicular to the contact surface 24. The spreading plates 25 are on the carriage 22 perpendicular to their planes, i.e. 1 perpendicular to the plane of the drawing, in opposite directions slidably mounted. For this two serve one above the other arranged guide rods 26 which are transverse to the direction of displacement C and extend horizontally. The spreading sheets 25 are retractable into the bag opening and closed this purpose to those facing the opening device 5 Tapered towards the end.

A is expedient for moving the spreading plates 25 Lever linkage 28 is provided, consisting of two over the common axis 29 articulated to each other in a scissor-like manner connected double-armed levers 30. The common Axis 29 is connected to the carriage 22.

One each represents the lever arms of the double-armed lever 30 engages on a support 31, the associated spreader plate 25 carries. The other lever arm of each double arm Lever 30 is each via a handlebar 32 with a Drive head movable in the slide sliding direction C. 33 connected. As a drive motor for the drive head 33 serves a piston-cylinder unit carried by the carriage 22 34.

The device works as follows:

By means of the winding device 12 and the latter wound carrier tapes 4, the bag 1st gradually pulled to the opening station 5. The Winding device 12 is stopped as soon as the Bag edge 2a, 3a of the foremost bag 1 the rear edge 14b of the cross rail 14 has reached. The stopping the winding device 12 can for example via a photocell. By means of the piston-cylinder unit 17 is the opening head 16 after Move up and the suction cup 18 to the bottom the second bag wall 3 located below and placed under vacuum. If the set vacuum is reached, the opening head 16 is moved down, whereby the bottom wall 3 of the bag overhead bag wall 2, which by the tensioned Carrying straps 4 is held, slightly lifted off and the foremost bag 1 is opened a crack. After this initial lifting of the second, lower one Bag wall 3 is by means of the piston-cylinder unit 21st the gripper 19 from his dash-dotted line in Figure 3 shown starting position in its in Figure 3 Grip position shown in dash-and-dot lines pivoted in, the terminal block 19a of the gripper 19th lies against the inside of the lower bag wall 3 and presses it against the suction cup 18. In this way the lower bag wall 3 is securely between the terminal block 19a of the gripper and the suction cup 18 clamped. Upon further movement of the opening head 16 downwards the lower bag wall 3 is taken down. Since the upper bag wall 2 is still attached to the carrier tapes 4 is glued, the bag walls 2, 3 form an im essentially rectangular bag opening Ö. Rear, the bag edge 2a, 3a is turned away part of the bag still held by the angle rails 13. The carriage 22 is now with the on the support surface 24 arranged filling material F in the direction of Opening station 5 moved, the each other approximated spreading plates 25, as can be seen from FIG. 4 into the bag opening Ö. About the Lever linkage 28 and the piston-cylinder unit 34 the spreading plates 25 are moved apart in opposite directions, insofar as this is the plastic bag to be opened 1 allows. After this has been done, the gripper 19 swung into its rest position and the vacuum on Suction cup 18 lifted. An insertion cylinder 35 pushes the filling material F from the support surface 24 between the Spreading plates 25 into the opened bag 1 until the filling F at the closed end of the bag triggers. As a result, the bag is supported by carrying tapes 4 solved. The filled bag is placed on the roller conveyor 36 transported away. As soon as the filled Bag has loosened from the straps 4, they will rolled up with the winding device 12 and thus the Bag chain to the opening station 5 towards B moved until the edge of the bag 2a, 3a of the next bag again the rear edge 14b of the cross rail 14 is reached Has.

Thanks to the scissor-like lever linkage 28 bags of different widths in are continuously spread with respect to a vertical longitudinal median plane of the device, without any adjustment work on the spreader to which the Spreader plates 25 belong, are required.

The exemplary embodiment shown in FIGS. 6 to 8 has the same principle Structure like the previously described embodiment, so that the above Statements analogously to the embodiment shown in Figures 6 to 8 hold true. This embodiment is particularly suitable for plastic bags wider width. In this embodiment, the horizontal feed path is 11 by a larger number of rails running perpendicular to the cross rail 14 13, 113, 213, 313 are formed, each at a distance from one another and parallel to one another are arranged. The rails are not yet used to guide and support the opened bag 1.

The ends 13b, 113b, 213b, 313b of the rails 13, 113, 213, 313 are each at a distance from the cross rail 14 and parallel to this arranged, horizontal support rail 37 connected so that the rails of cantilever from the support rail 37 to the cross rail 14. The distant ends 13b, 113b, 213b, 313b are expedient, as indicated by arrows in FIG. 7, adjustable relative to the mounting rail so that it can be adjusted to the respective bag width are adjustable and can also be adapted to the respective bag length.

If, as shown in Figures 6 to 8, a larger number of rails are provided, then the free ends 113a, 213a, 313a should be different Have a distance to the cross rail 14. The free ends 313a of the rails 313 which are closer to a vertical central plane E-E running parallel to the rails, should have a distance a1 from the cross rail 14 which is greater than the respective one Distance a2 of the free ends 213a and the distance a3 of the free ends 113a, rails 213 and 113, respectively, which are further outward from the central plane E-E this ensures that the bags 1 are fed along the horizontal Feed path 11 are initially adequately supported downwards and not unintentionally hang down. It also ensures that after the partial opening of the Bag according to Figures 6 and 8 when inserting the contents, e.g. a piece of cheese, this partially opened bag completely from the rails 113, 213 and 313 can be pulled down without getting stuck on the rails.

Claims (11)

Device for opening plastic bags (1) which are detachably adhered to one another in a scale-like manner on at least two carrier tapes (4) running at a distance from one another and perpendicular to the opening edge (2a, 3a) of the bags (1), with an essentially horizontal feed path (11) , along which the plastic bags can be fed gradually to an opening station (5) by pulling on the carrying bands (4), with a contact surface (14a) provided at the opening station (5), on which the area on the opening side of the first bag wall (2) is tensioned Carrying tapes (4) are held and fixed, with a pneumatic opening device (18), by means of which the opposite second bag wall (3) can be lifted from the first bag wall (2) for opening the bag (1), and with a roller conveyor (36) for the removal of filled bags from the opening station (5) and with a winding device (12) arranged next to the opening station (5) For winding the carrier tapes (4) detached from the plastic bags (1), characterized in that the feed track (11) is arranged at a distance above the roller track (36) and at the end of the feed track (11) a cross rail (14) is provided, the Underside (14a) of the contact surface forms that the pneumatic opening device comprises at least one suction cup (18) which is arranged on an opening head (16) which is vertically movable perpendicular to the contact surface (14a) and is movable from below towards the contact surface (14a) , and serves for the initial lifting of the second bag wall (3), and that a gripper (19) is arranged on the opening head (16), which is pivotably mounted on the opening head (16) about an axis (20) running parallel to the transverse rail (14) and after the initial lifting of the second bag wall (3) on the inside of it can be pressed in such a way that the second bag wall (3) is clamped between the gripper (19, 19a) and the suction cup (18). Apparatus according to claim 1, characterized in that the feed path (11) is formed by at least two rails (13) which run perpendicular to the cross rail (14) and are arranged at a distance from one another. Apparatus according to claim 2, characterized in that the feed path (11) is formed by two angular profile rails (13) running perpendicular to the cross rail (14) and spaced apart from one another by the bag width (b), on the horizontally running angular legs (13a) of which the longitudinal edges the bag (1) should rest. Apparatus according to claim 3, characterized in that the mutual distance between the angle profile rails (13) is adjustable. Apparatus according to claim 2, characterized in that the ends (13b, 113b, 213b, 313b) of the rails (13, 113, 213, 313) remote from the cross rail (14) are each spaced apart from the cross rail (14) and are arranged parallel to this support rail (37) and that the rails (13, 113, 213, 313) project freely from the support rail (37) to the cross rail (14). Apparatus according to claim 5, characterized in that the free ends (313a) of those rails (13, 113, 213, 313) which are closer to a vertical central plane (EE) running parallel to the rails have a greater distance (a1) from them Cross rails (14) have the free ends (113a, 213a) of the rails (13, 113, 213) which are further outward from the central plane (EE). Device according to claim 5 or 6, characterized in that the distal ends (13a, 113a, 213a, 313a) of the rails are adjustable relative to the support rail (37). Device according to Claim 1, characterized in that the suction cup (18) is arranged in the immediate vicinity of the opening edge (2a, 3a) of the foremost bag (1) which is in the opening position. Device according to one of claims 1 to 8, characterized in that the bags (1) fixed to the carrying bands (4) are wound on a cylindrical core (6) to form a roll (7) and that a braking device (10) is provided, which acts on an axis (8) carrying the core (6). Device according to one of claims 1 to 9, characterized in that two spreading sheets (25) which can be moved into the bag opening (Ö) on a slide (22) which can be displaced in the longitudinal direction of the bag (C) and which has a support surface (24) for the filling material (F) has, is arranged that the planes of both expansion plates (25) extend substantially in the direction of displacement (C) of the slide (22) and perpendicular to the support surface (24), that the expansion plates (25) on the slide (22) perpendicular to their Levels are slidably mounted in opposite directions and can be moved apart after entering the bag opening (Ö). Apparatus according to claim 10, characterized in that a lever linkage (28) is provided for the opposite movement of the expansion plates (25), consisting of two double-arm levers (30) articulated to one another in scissors-like fashion, the common axis (29) of which is connected to the slide (22 ) is connected, one lever arm each engaging a support (31) carrying the associated expansion plate (25) and the other lever arm each via a link (32) with a carriage motor (34) which can be moved in the direction of slide displacement (C) and can be driven Drive head (33) is connected.

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