EP0187351A1 - Device for picking up single spread out fabrics, preferably plastic fabrics - Google Patents

Abstract

1. A device for picking up individual textile parts or textile bags, lying flat and preferably of plastics, for lifting or removing from a stack (8), in which at least two brushes (18, 19), which can be pressed against the stack and engaging in the uppermost textile part (8a) or the uppermost textile bag, are held so as to be movable towards and away from each other on a lifting and pivot arrangement (12), wherein the brushes have steel bristles (26), which extend inclinedly in the engagement direction at least in the region of their free ends, characterized in that the brushes (18, 19) are arranged at the free ends of pivot levers (20) which are held at a spacing and connected to a pivot drive (24), and in that the free ends of the pivot levers (20) with the brushes (18, 19) for the release of the actual picked-up textile part (8a) or textile bag can be transferred beyond its initial position for picking up the textile part or textile bag to a much closer position.

Description

The invention relates to a device for detecting individual flat-lying fabric parts or fabric bags, preferably made of plastic, in particular for lifting or lifting at least a portion of the fabric parts or fabric bags from a stack with at least one fabric part held on a lifting and / or swiveling device or the gripper element gripping the bag.

While you can usually use suction pads to grasp individual flat-lying film sections or film bags made of plastic or to separate these sections or bags, this is practically not possible with the above-mentioned fabric parts or fabric bags because of their air permeability. For this reason, devices of the type mentioned in the introduction have been developed, which have hook-like gripper elements in the form of individual claws which only engage in the tissue part to be gripped at a few points. Both when lifting only a section and when grasping and lifting a tissue part or tissue sack, tensile forces are exerted on the tissue by the claws engaging in the tissue. When lifting only a section of the fabric part or fabric bag, it must be held against displacement until the claws of the gripper elements engage, before the claws can be released after the claws have been engaged. When lifting the entire fabric part or sack from a stack and transferring it to another location using gripper elements in the form of individual claws, the fabric part or the sack must also be kept taut during the conveying path. In both cases there is a great risk of local damage due to the engagement of the claws in the tissue parts and the tensile forces exerted by them on the tissue.

In addition, the claws must penetrate relatively deep into the tissue in order to be able to grasp it safely. As a result, there is a risk that the claw tips will reach through the uppermost tissue part of the stack or sack when a tissue part or tissue sack is lifted from a stack and also grasp the tissue part underneath. This results in problems and malfunctions in the further devices downstream of the separation when separating flat-lying tissue parts from a stack.

The invention has for its object to develop a device of the type mentioned in such a way that the disadvantages described avoided and a non-positive detection of the tissue parts achieved with gentle treatment and when lifting or lifting a individual tissue parts from a stack secure separation is guaranteed.

To achieve the above object, the device according to the invention is characterized in that at least one brush equipped with a plurality of bristles is provided as the gripper element, which can be pressed in the direction transverse to the tissue plane against the tissue part to be detected in each case and with its bristles engaging in the tissue part in the direction is held transversely to the longitudinal extent of the bristles back and forth on the lifting and / or pivoting device.

Due to the brush equipped with a large number of bristles, even with a relatively strong pressure of the brushes against the tissue parts in the direction transverse to the tissue plane with a correspondingly dense arrangement of the bristles compared to the density of the tissue, there is no penetration of the individual bristles through the tissue, but only one Intervention in its surface structure.

Using only one brush, which is held on a lifting and swiveling device, individual flat-lying fabric parts or fabric bags can be lifted from a base or from a stack for the purpose of separation, for example in their edge area, and transferred to another gripper device, whereby it is only necessary to press the tissue part or the sack onto its base or the stack in the region outside the attack of the brush while the tissue part or sack is being gripped by the brush. To lift the tissue section, the brush is first pressed in the direction transverse to the tissue plane on the tissue part to be detected and then pivoted so that the tissue between the brush and the tissue on the base or the stack pressing device is tensioned. Due to the pressure of the individual bristles on the fabric threads as a result of the pivoting movement of the brush, sufficient stiffness of bristles between them and the fabric threads results in sufficient static friction which, when added up over the surface of the brush, ensures that the individual fabric parts are securely gripped, so that the fabric part is maintained the tension can be raised by means of the lifting device and transferred to a gripper element.

If the entire tissue part is to be separated or lifted by means of the device designed according to the invention, the invention provides at least two separate brushes, both of which can be pressed in the direction transverse to the tissue plane against the tissue part to be detected and with their bristles engaging in the tissue part against each other in the direction transverse to the longitudinal extension of the bristles back and forth _{- are} held on the lifting and / or swiveling device.

To grasp and lift off the respective tissue part, the brushes in this arrangement are moved so far from each other after the pressure has been applied to the tissue in the direction transverse to the tissue plane that the area of the tissue located between the brushes is stretched. In this position of the brushes, the tissue part or the tissue bag can be lifted off the base or the stack and transported to another location.

To release the tissue part or tissue section from the brushes, it is only necessary to bring the brushes closer together, so that the adhesive effect generated between the bristles and the tissue threads by the tension is eliminated.

It is particularly expedient if the bristles are designed as steel bristles which, in comparison to the individual fabric threads or fabric tapes also provided in the case of plastic fabrics, have a relatively high bending stiffness and elasticity and in this way promote the grasping of the respective fabric parts.

To improve the engagement of the bristles in the tissue surface, it is provided in a preferred embodiment of the device that the bristles of the individual brushes are inclined in the direction of engagement at least in the region of their free ends. As a result, when the tissue parts or tissue sacks are grasped, the bristles additionally catch or engage under the individual tissue threads or ribbons when the brush or the brushes grasp the tissue part or the tissue sack.

It is expedient if the or each brush is connected to the free end of a swivel lever on which a swivel drive engages. The pivot lever can itself be designed as a lifting device or can be connected to a lifting device in order to be able to grasp and also lift the tissue part by means of the brush held at its free end.

For grasping the entire tissue part or the tissue bag and lifting it off its base or from a stack, it is particularly expedient if two brushes held at a distance from each other are held at the free ends of spaced levers which can be pivoted towards and away from one another. In this embodiment, the swivel levers can expediently be designed as double-armed levers and rotatably mounted on a vertically movable crossmember and with their ends facing away from the brushes via a telescoping end Drive connected to each other. This results in a particularly simple constructive design of the device for grasping and lifting the tissue parts or tissue sacks, wherein a movable arrangement of the cross-piece enables individual storage of the tissue parts or tissue sacks at another location. The swivel drive for the swivel levers can be designed relatively simply in a mechanical design, for example as a spindle drive. However, a piston-cylinder arrangement is preferred as the swivel drive.

The aforementioned drive for the swivel lever enables such an engagement of the brushes in the tissue part to be detected that, for releasing the tissue part, for example after transfer to another location, the brushes can be moved together beyond their initial position, thereby automatically releasing the Allow tissue part. If necessary, the brushes can also be returned to the release position against the action of the swivel drive which spreads them by means of a spring.

In order to grasp only a section of larger tissue parts or bags or also to completely lift smaller tissue parts from their base, in one embodiment variant of the invention three brushes arranged directly next to one another can be provided, one of which is held so that it can be moved back and forth relative to the other two . A swiveling of the brushes in the direction of the tissue plane is not necessary for grasping the tissue sections or tissue parts with this device, since the brushes already grasp the tissue in the manner described above due to their relative movement.

In all the devices described, the brushes are expediently designed as flat brushes, i.e. their free ends of the bristles end in a common plane.

Instead of the last-described design with three brushes arranged next to one another, according to another embodiment, at least two brushes in the form of concentrically arranged rings can also be provided and held pivotable relative to one another about their central axis. This device is also particularly suitable for the detection of smaller tissue parts or for lifting a tissue section of larger tissue parts, for example for the purpose of separation.

Instead of the flat brushes, according to a further embodiment variant of the device, at least two brushes can also be designed as round brushes which can be rotated about axes running parallel to the plane of the fabric part. In the same way as with the brushes in the form of concentrically arranged rings, the opposite movement of the brushes can be generated with a single drive, only relatively small rotary movements of the brushes being required to tighten the tissue part located between the brushes.

If the device described is to be used for grasping tissue parts or bags of larger dimensions, it is advisable to provide the brushes individually or in the multiple arrangement described in the region of the corners of the tissue part or bag for engagement.

The device described is not only suitable for the detection and lifting of tissue parts or bags, but it can be according to a special embodiment can also be used to open sack mouths in that at least two brushes which can be moved back and forth are assigned to the tissue walls lying one on top of the other in the flat state of the sack and are arranged opposite one another in the direction perpendicular to the plane of the tissue walls. It is not necessary for the two opposite pairs of brushes to perform a movement perpendicular to the plane of the tissue walls, but it is sufficient if only one pair of brushes executes this movement and the other pair of brushes is held in its position.

The drawing shows exemplary embodiments of the invention in a schematic representation.

• Fig. 1 eine Vorrichtung gemäß der Erfindung zum Anheben eines Randbereiches eines jeweilig oberen Gewebeteiles oder -sackes von einem Stapel zum Zwecke der Vereinzelung in ihrer Ausgangsstellung,
• Fig. 2 die Vorrichtung nach Fig. 1 in einer anderen Position,
• Fig. 3 die Vorrichtung nach den Fig. 1 und 2 unmittelbar vor Erreichen ihrer Ausgangsposition gemäß Fig.l,
• Fig. 4 eine Vorrichtung zum Erfassen und Überführen von Gewebeteilen oder -säcken von einem Stapel auf einen Ablagetisch in einer Frontansicht,
• Fig. 5 die Vorrichtung nach Fig. 4 mit Blick in Richtung des Pfeiles A,
• Fig. 6 in vergrößerter Darstellung eine Einzelheit der Fig. 4, nämlich die Seitenansicht der eigentlichen Greiferanordnung in ihrer Ausgangsstellung,
• Fig. 7 die Anordnung nach Fig. 3 in der Greifstellung,
• Fig. 8 die Anordnung nach den Fig. 3 und 4 in der Freigabestellung,
• Fig. 9 die Seitenansicht einer Variante einer Greifervorrichtung mit drei nebeneinander angeordneten Bürsten,
• Fig.10 die Draufsicht auf die Anordnung nach Fig. 9,
• Fig.11 einen Schnitt entlang der Schnittlinie XI-XI in Fig. 12 durch eine andere Bürstenanordnung,
• Fig.12 einen Blick gegen die Unterseite der Anordnung nach Fig. 11,
• Fig.13 die Seitenansicht gegen eine weitere Variante einer Bürstenanordnung.
• Fig.14 rein schematisch die Verwendung einer Anordnung nach den Fig. 4 bis 8 zur Öffnung einer Sackmündung.

Show it:

• 1 shows a device according to the invention for lifting an edge region of a respective upper fabric part or sack from a stack for the purpose of separation in its initial position,
• 2 shows the device according to FIG. 1 in a different position,
• 3 shows the device according to FIGS. 1 and 2 immediately before reaching its starting position according to FIG. 1,
• 4 shows a device for capturing and transferring tissue parts or bags from a stack onto a storage table in a front view,
• 5 shows the device of FIG. 4 with a view in the direction of arrow A,
• 6 shows an enlarged view of a detail of FIG. 4, namely the side view of the actual gripper arrangement in its starting position,
• 7 shows the arrangement according to FIG. 3 in the gripping position,
• 8 shows the arrangement according to FIGS. 3 and 4 in the release position,
• Fig. 9 shows the side view of a variant of a gripper device with three brushes arranged side by side,
• 10 shows the top view of the arrangement according to FIG. 9,
• 11 shows a section along the section line XI-XI in FIG. 12 through another brush arrangement,
• 12 shows a view against the underside of the arrangement according to FIG. 11,
• 13 shows the side view against a further variant of a brush arrangement.
• Fig. 14 purely schematically, the use of an arrangement according to FIGS. 4 to 8 for opening a bag mouth.

1 to 3, a hydraulically actuated pressure device 2 is provided at one end of a cantilever arm 1 which is held in a stationary manner and has a pressure stamp 2a which can be raised and lowered.

At the other free end of the cantilever arm, a piston-cylinder arrangement 3 is articulated, which can be pivoted about its articulation point on the cantilever arm 1 via a further piston-cylinder arrangement 4.

At the lower end of the piston-cylinder arrangement 3, a gripper element in the form of a brush 5 is provided, the bristles 6 of which, in the example shown, extend inclined away from the pressing device 2.

The piston-cylinder arrangements 3 and 4 together form a lifting and swiveling device for the brush 5 in order to be able to transfer it to the different positions shown in FIGS. 2 and 3.

The cantilever arm 1 with the elements held thereon is arranged above a stack 8 of fabric parts or fabric bags located on a base 7. Laterally next to the stack 8, a gripper device 9 can be seen, the gripper arms of which are equipped with clamping jaws and can be transferred into the gripping and release position and which is also held in the direction of the double arrow 10 by means of a drive device not shown in the drawing.

The method of operation of the described device results from FIGS. 1 to 3.

Starting from the starting position in FIG. 1, to lift off the uppermost fabric part or fabric bag 8a, the pressure stamp 2a of the pressure device 2 is lowered and pressed onto the stack 8, and the brush 5 with its bristles 6 is also pressed onto the stack 8 by actuating the piston-cylinder arrangement 3 lowered and pressed against the stack. In this position, the piston-cylinder arrangement 3 is pivoted so far towards the gripper 9 by the piston-cylinder arrangement 4 which is further provided that the bristles 6 engage in the uppermost tissue part or the uppermost tissue bag 8a between the pressure stamp 2a and the pressure or point of engagement of the bristles 6 is stretched. In this way, a frictional or form-fitting connection is created between the bristles and the tissue threads or fabric tapes captured by them, so that when the brush 5 is raised, the tissue part captured by the bristles 6 is also lifted.

2, the position of the brush 5 in engagement with the uppermost fabric part or fabric bag 8a still lying on the stack is shown in solid lines and the broken line shows the raised position of the brush 5 and the top fabric part or fabric bag 8a entrained by this brush . In this dashed position of the brush 5, the Gripper device 9 are actuated in order to grasp the edge of the fabric part or fabric bag 8a which projects beyond the brush 5 and faces the gripper device 9. After the gripper device 9 has gripped this edge of the tissue part or tissue bag 8a, the piston-cylinder arrangement 3 with the brush 5 held thereon is pivoted back in the direction of the pressing device 2, so that the bristles 6 of the brush 5 are in a disengaged position with the tissue part or tissue bag 8a be transferred. The tissue part or tissue bag 8a which is gripped by its one edge by the gripper device 9 can now be removed from the stack 8 and transported away as a single tissue part or tissue bag. After returning the piston-cylinder arrangement 3 to the position shown in FIG. 1 with the aid of the piston-cylinder arrangement 4, the described process can be repeated in order to further separate the tissue parts or tissue bags forming the stack.

In the example shown in FIGS. 4 and 5, a lifting device 12 which is movable in its longitudinal direction is held on a carrier 11 and is connected at its free end facing away from the carrier 11 according to FIG. 5 to a supporting beam 13, which in turn is at the ends is each equipped with a similar gripping device, generally designated 14.

In the example, the lifting device 12 is designed as a piston-cylinder arrangement, the piston rod of which is connected to the cross member 13. 4, the lifting device 12 fastened in the direction of the double arrow 17 to the supporting beam 11 with the associated gripping devices 14 is shown in solid lines above a stack 8 and in dashed lines in a position above a depositing table 16 posed. In the example shown, the gripping devices 14 are each equipped with two brushes 18 and 19 which can be moved back and forth, the design and operation of which are described in detail in connection with FIGS. 6 to 8.

In the left part of FIG. 4 it can be seen that the brushes 18 and 19 have gripped the top fabric part 8a or the top fabric bag from the stack 8 and lifted it up to the position shown in the left part of FIG. 1 above the deposit table 16 to convict.

The design of the gripping devices results from FIGS. 6 to 8. In these figures, the gripping devices are shown without an outer casing in order to better explain the functionality.

It can be seen that the brushes 18 and 19 are fastened to the lower free ends of the levers 20, which are designed as double-armed levers and are held on a crossbar 21 via pivot axes 22 and 23, and at their ends remote from the brushes 18 and 19 via a telescope acting drive 24 are interconnected. The telescopic drive 24 engages via articulation points at the upper ends of the double-armed lever 20 and is designed in the example shown as a piston cylinder arrangement which can be acted upon on both sides. When the piston-cylinder arrangement is actuated, the brushes 18 and 19 are moved towards or away from one another in order to achieve the positions shown in FIGS. 7 and 8.

Wenr the pivot axes 22 and 23 for the double-armed lifts 20 not in stationary supporting parts, for example a casing of the gripping arrangements 14 are mounted, the two brushes, to achieve the movement of symmetry 18 and 19 upon actuation of the drive 24, an additional slide ^g onallenker 25 be provided, which is hinged to the double-armed levers 20th

The brushes 18 and 19 shown in Figs. 4 to 8 are designed as flat brushes, i.e. their bristles 26 end in a common plane. The bristles 26 are designed as steel bristles. The figures show that the bristles of the brush 18 with their free ends in one direction and the bristles 26 of the brush 19 with their free ends in the opposite direction are inclined. The inclined course of the free ends of the brushes corresponds to the direction of engagement of the brushes in the flat-lying tissue part or tissue bag 8a to be detected.

In order to prevent wear of the brushes, the bristles can have hardened and ground tips at their free ends. In all the devices described, the brushes are held interchangeably on the levers assigned to them, so that they can be replaced and replaced when worn. In this way it is possible to use brushes with bristles of different spacing and different stiffness, depending on the structure of the tissue part or tissue bag to be gripped by the brushes. Brushes whose bristles are so closely arranged that a bristle is provided on at least 4 mm ² and the brush has a dimension of at least 4 cm ² have proven useful for gripping plastic fabric bags, so that more than 100 at a point of attack of the brush Bristles come into contact with the tissue surface.

For grasping a flat tissue part, which 6 and 7 is again designated 8a, the brushes 18 and 19 in the position shown in FIG. 6 are lowered onto the fabric part 8a and, with simultaneous pressure on the fabric part, by actuating the piston-cylinder arrangement 24 into that shown in FIG. 7 Position transferred. This results in a tightening of the section of the fabric part 8a located between the brushes 18 and 19 and a force-locking grasping of the fabric part by the bristles 26 of the brushes 18 and 19. In this position according to FIG. 7, the fabric part 8a can be removed from its base, for example from the stack 8 shown in FIG. 4, lifted off and transferred to another location, for example according to FIG. 4, on the storage table 16. To deposit the fabric part 8a, the brushes 18 and 19 are transferred into the position shown in FIG. 8 by means of the piston-cylinder arrangement 24. Characterized in that the brushes 18 and 19 are moved against each other, the bristles 26 of the brushes 18 and 19 come out of engagement with the surface of the fabric part 8a, so that the fabric part 8a is released from the bristles 26 of the brushes 18 and 19 and can be deposited. FIG. 8 shows that to release the tissue part, the brushes 18 and 19 are brought into a more approximate position than is the case according to FIG. 6 when the tissue part is gripped. In the position of the brushes 18 and 19 as shown in FIG. 8, the fabric part comes out of the action of the bristles 26 of the aforementioned brushes solely due to the force of gravity, so that any manipulations for the release of the fabric parts are not necessary.

In order to achieve a return of the double-armed levers 20 or the brushes 18 and 19 from the position according to FIG. 8 to the starting position according to FIG. 6 even without a complicated control, in the exemplary embodiment of FIGS. 6 to 8 the cross member 21 a Suspension mechanism 27 is provided which, when the piston cylinder arrangement 24 is released in the position according to FIG. 8, acts on the right-hand double-armed lever 20 in the position shown in FIG. 8 by the spring 27a tensioned in this position and the return bolt 27b under the action of this spring, and this in the in Fig. 6 pivots back position.

• Wie aus den Fig. 4 bis 8 hervorgeht, ist es zweckmäßig, bei der Erfassung größerer Gewebeteile bzw. von Säcken die Bürsten jeweils im Bereich der Ecken des Gewebeteiles oder Gewebesackes zum Eingriff in das Gewebeteil vorzusehen. Hierdurch wird eine Straffung des gesamten Gewebeteiles bzw. Gewebesackes erreicht, so daß dieser in die jeweils gewünschte Stellung mittels der beschriebenen Einrichtung überführt werden kann.

Devices of the design shown in FIGS. 4 to 8 have already proven extremely useful in long-term trials for separating tissue bags by lifting off the uppermost bag of a stack. _:

• As can be seen from FIGS. 4 to 8, it is expedient to provide the brushes in the region of the corners of the fabric part or fabric bag for engaging the fabric part when detecting larger tissue parts or bags. This results in a tightening of the entire tissue part or tissue bag, so that it can be transferred to the desired position by means of the described device.

Instead of the individual brushes 18 and 19, it is also possible to use brush arrangements according to FIGS. 9 and 10 or 11 and 12, which, however, are rather provided individually for the detection of smaller tissue parts.

In the embodiment according to FIGS. 9 and 10, three brushes 28, 29 and 30 which can be moved relative to one another are provided, of which the brushes 28 and 30 are held stationary on the lifting device, for example via the holding bracket 31 shown in FIG. 9, while the brush 29 is held on an upstanding web 32, which in turn is attached to the piston rod of a piston-cylinder arrangement 33 in such a way that the brush 29 relative to the brushes 28 and 30 in the direction of the double arrow 34 is movable. Again, the bristles of the brushes 28 and 30 are formed such that their free ends in one direction and the bristles of the brush 29 are inclined in the other direction, so that the portion of the tissue part gripped by the brushes between the brushes is under tension is held.

11 and 12, two brushes 35 and 36 are provided in the form of concentrically arranged rings. The brush 35 is fastened to the rotatably held housing of a rotary drive 37, while the brush 36 is connected to a drivable shaft 38 or rotary drive 37. In this embodiment, too, the bristles of the brushes 35 and 36 are inclined in opposite directions, at least at their free ends, in order to achieve the effect already described in connection with the other figures when grasping the tissue part.

Finally, a brush arrangement is shown in FIG. 13, in which two brushes 39 and 40 are provided in the form of round brushes, which keep pivot axes 41 and 42 pivotable relative to one another in the direction of the double arrows shown, about axes of rotation 8a to be grasped parallel to the plane ces tissue part 8a are. It is not necessary to provide bristles on the entire circumference of the round brushes since only relatively small angular movements of the brushes 39 and 40 about their axes of rotation 41 and 42 are required to tighten and release the tissue part 8a to be detected.

Fig. 13 shows that the bristles 26 of these brushes in total in the direction of engagement. that is to say, inclined in an inclined manner. P.est training is also in the other brushes described above instead of their execution with only inclined running free ends possible.

The drive required for the brushes 39 and 40 in FIG. 13 is not shown in the drawing, just as for the arrangements according to FIGS. 9 to 12, the lifting device connected to the respective gripping devices is not shown for reasons of clarity. However, the lifting device can be designed in the same way as is shown in FIGS. 4 and 5.

The brush arrangements according to FIGS. 9 to 13 can also be used instead of the individual brush 5 in connection with devices according to FIGS. 1 to 3 for lifting only a portion of the tissue part or bag to be detected in each case.

The arrangements described according to FIGS. 5 to 13 are not only suitable for lifting and separating tissue parts or tissue bags, but they can also be provided in an arrangement according to FIG. 14 for opening sack openings. In the example in FIG. 14, anoronuncenes according to FIGS. 4 to 8 are provided, each with two brushes 18 and 19 that can be moved back and forth, which vertically guide the fabric walls 43a and 43b of the sack designated 43 in the flat state in FIG. 14 move to their level and thus remove from each other so that a corresponding opening 44 of the bag 43 is reached at the mouth thereof.

It is sufficient if only one pair of brushes 18, 19 is moved via a corresponding lifting device, while the other pair of Earsten is held back and forth only to achieve the intervention.

Claims (14)

1. Device for detecting individual flat-lying fabric parts or fabric bags, preferably made of plastic, in particular for lifting or lifting at least a portion of the fabric parts or bags from a stack with at least one held on a lifting and / or pivoting device, the respective fabric part or the gripper element gripping the bag, characterized in that at least one brush (5; 18, 19; 28 to 30; 35, 36; 39.40) equipped with a plurality of bristles (6; 26) is provided as the gripper element, that the brush (n) can be pressed in the direction transverse to the tissue plane against the tissue part (8a) to be detected and with its bristles engaging in the tissue part can be moved back and forth on the lifting and / or swiveling device (3, 4 or 3) in the direction transverse to the longitudinal extension of the bristles 11 to 14) is held. 2. Device according to claim 1, characterized in that at least two separate brushes (18, 19; 28 to 30; 35, 36; 39, 40) are provided in order to lift off the entire fabric part (8a) or bag are held transversely to the longitudinal extension of their bristles (26) against each other back and forth on the lifting and / or pivoting device (3,4 or 11 to 14). 3. Apparatus according to claim 1 or 2, characterized in that the bristles (16) are designed as steel bristles. 4. Device according to one of claims 1 to 2, characterized in that the bristles (16) of the individual brushes (5; 18 or 19; 28 to 30; 35.36; 39.40) at least in the region of their free ends The direction of engagement is inclined. 5. Device according to one of claims 1 to 4, characterized in that the or each brush (5; 18 or 19; 28 to 30; 35.36; 39.40) with the free end of a pivot lever (3 or 12th ) is connected to which a swivel drive (4; 24) engages. 6. The device according to claim 4, characterized in that two spaced-apart brushes (18, 19) are held at the free ends of spaced levers (20) which can be pivoted towards and away from one another. 7. The device according to claim 6, characterized in that the pivoting levers are designed as double-armed levers (20) and are rotatably mounted on a vertically movable crossmember (21), and that the brushes (18, 19) have their ends remote from the levers via a telescopically acting Drive (24) are interconnected. 8. Device according to one of claims 5 to 7, characterized in that a piston-cylinder arrangement is provided as swivel drive (24). 9. Device according to one of claims 1 to 4, characterized in that three brushes (28 to 30) arranged directly next to one another are provided, one of which is relative to the other two is held back and forth. 10. Device according to one of claims 1 to 9, characterized in that the brushes (18,19; 28 to 30; 35,36) are designed as flat brushes. 11. Device according to one of claims 1 to 4, characterized in that at least two brushes (35,36) are provided in the form of concentrically arranged rings and are held pivotable relative to one another about their central axis (38). 12. Device according to one of claims 1 to 4, characterized in that at least two brushes (39, 40) are designed as round brushes which can be rotated about axes (41, 42) running parallel to the plane of the fabric part (8a). 13. Device according to one of the preceding claims, characterized in that the brushes (18, 19; 28 to 30; 35, 36; 39, 40) individually or in multiple arrangement in the region of the corners of the fabric part (8a) or of the fabric bag Intervention are provided. 14. Device according to one of the preceding claims, characterized in that for opening sack orifices at least two brushes (18, 19) which can be reciprocally moved back and forth are assigned to the fabric walls (43a, 43b) lying one above the other in the flat state of the sack (43) and opposite are arranged movable relative to each other in the direction perpendicular to the plane of the fabric walls.

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