DE19650653C1 - Method and device for separating and opening sacks - Google Patents

Abstract

The method involves a suction device (24,25), which is lowered to a stack in order to pick up bags individually for conveyance away longitudinally over the stack. The suction device on being lowered onto the stack (13) is held at an adjustably fixed distance from the uppermost bag. For opening individual bags lying on a base, suction devices are movable against the bag walls near the bag opening. By removal of the suction devices (72,73) the bags are opened from one another and finally are moved away longitudinally to the base. The upper movable suction device (72) is lowered onto the upper bag wall and is then held in an adjustable fixed position above the upper bag wall. All the suction devices (24,25,72,73) are fed with an uninterrupted vacuum at least during individualisation/opening.

Description

The invention relates to methods and devices for handling empty bags before attaching them to a bagging neck. We Significant steps here are the separation of the bags lie flat in a stack in a sack magazine, as well as that Opening the bags, which is the retraction of bag spreaders and Attachments in the bag opening allows.

DE 23 64 548 A1 describes a device known for separating sacks lying one on top of the other a suction element in the form of a suction box is used. This points two to each other at its bottom suction opening parallel straight lower side wall edges and two transverse to it running concave or convex curved lower front wall edges on. A suction element of this type is said to have a low vacuum generate high holding forces.

DE 42 05 075 A1 describes a method and a device described for separating and opening stacked bags, where the separation by means of vacuum cups and the opening done with adhesive tape. Design and movements of the Vacuum cups are not disclosed in detail.

Methods and devices of the type mentioned are in detail in DE 38 40 646 A1 of the applicant described a high power clip-on describes. The one described there  Procedure for picking up the sacks in the area of the sack floor with movable suction devices with a subsequent Pulling backwards away from the stack of bags and a subsequent one Drive the sack forward towards the sack spreader as well opening the bag opening with movable suction means has proven itself and forms the basis for this invention dung. For all sacks with airtight sack walls even at a high frequency of separation and attachment no problems in handling the bags with the above Vacuum cleaners are found. For sacks made of air permeable However, casual tissue malfunctions have occurred that can represented in such a way that the suction means when separating lifting several bags from the bag stack at the same time, or that the suction means the unopened when opening the bag sack with sack walls lying against each other from the surface take off. This can be interpreted as a consequence of the air pressure permeability of the lower part exercised by the movable suction cup print on additional sacks in the sack stack or on the lower sack wall of the bag to be opened affects, so that this too there is a sufficient pressure difference for lifting.

Of that starting from the object of the present invention, methods and to provide devices that function safely wise even with bags made of breathable fabric len. Fabrics of this type can be made of plastic, especially poly propylene, or from natural fibers, e.g. B. jute.

The inventive method for solving this consists in Separate the bags in that the suction means when lowering on the stack of bags at an adjustable fixed distance be stopped by the top sack, or when opening individual bags in that the above Ren movable suction means lowered on the upper bag wall  and each at an adjustable fixed distance from the top Bag wall are stopped. It is preferably provided that the Vacuum cleaner with a continuous negative pressure be charged. In particular, it is provided that the sack after lifting the upper suction means when spreading / for further transport against the negative pressure of the suction means is torn down.

The mode of operation of this procedure is that by stopping the movable suction means at a distance from the top wall of the bag the possibility of excessive Vacuum build-up, the sackwan located further down transfers, is avoided, but that with a suitably large Volume flow to the suction means or sufficient flow speed of the upper sack or the upper sack wall automatically from the sack below or the lower one Sack wall loosens and is sucked in by the suction means, whereby after application to the suction opening of the suction means so there is firm adhesion that there is movement of the suction means away from the stack of bags or from the base with the desired one Success of separating or opening can be initiated. Due to the fact that only the distance between the suction cups medium to the upper sack or the upper sack wall the possibility arises without a control effort to promote constant volume flow or constant negative pressure to the To leave vacuum cleaner pending, which makes the control essential is simplified. The suction means are relative high volume flow operated at a relatively low vacuum. The energy input for the corresponding suction fan can be here at be reduced. In a particularly inexpensive version, the Vacuum in the suction means are monitored and the at constant fan performance after detecting a sack in the Area of the bag bottom or a bag wall in the area of Vacuum build-up or pressure drop entering the bag opening  Control signal for the subsequent lifting of the movable upper Vacuum cleaner can be used.

Further aspects of the invention will be described with reference to the ß device can be clarified. These are with the Device for separating sacks characterized net that control means are provided on the suction means, which the suction opening of the suction means in an adjustable predetermined minimum distance from the surface of the upper sack stop, or at the device for opening individual bags in that control means on the upper movable suction cup Means are provided that the suction opening in one adjustable predetermined minimum distance to the upper bag wall stop. The suction means can be closed and closed with control valves be switched off as usual. In preferred next Education is provided that the suction means with a suction blowers are permanently open. With the characteristic of standing dig open connection between suction fan and suction means In particular the possibility is highlighted on tax nerves to dispense with tiles in the vacuum connection lines and thus the device over known devices that the Apply negative pressure if the sacks are to be gripped, and switch off if further transport is to take place, essential to simplify. This does not preclude that simple rule flaps in the lines are provided to the desired Set negative pressure when the suction fan is not regulating has possibilities, or if different suction means for ver individually on the one hand and for opening on the other hand by one common seed suction fan are applied and adjusted individually Need to become.

In a preferred embodiment, a pressure sensor can be attached to the suction cup means or in the line between suction means and suction be arranged as a signal generator for a Hubbewe  supply of the suction means in the event of a vacuum build-up or pressure waste due to the application of a bag wall to the intake opening the suction means is switched.

Non-contact sensor means or em Sensitive, smooth-running button means can be provided without Address feedback on the bag stack. This execution For the sake of completeness, shapes must be named and labeled claim. However, the preferred form of the control means are arranged at right angles to the suction opening of the suction means, name stop bars projecting downwards. Have this the advantage of a structurally simple, cheap construction, which special signal processing can become superfluous. The Placing the stop bar itself ends the lowering the movable suction means. In addition, this has staltung the beneficial effect that the suction opening and the wall of the sack against the stop to form a Z-profile is deformed, creating a stiffener over the entire sack width arises in the area of the bag bottom. This has the advantage that with suction means of a certain length or with in one certain distance from each other arranged suction bags different widths can be handled easily, even if this laterally over the extreme width of the suction cup survive medium.

In a preferred embodiment, the stop bar is via elongated holes adjustable relative to the suction opening level of the suction means arranged. This allows a simple adjustment for customization the device on sacks with different air permeability of their tissue. The adjustment range of the above Elongated holes can be so large that the stop bar up can be withdrawn into the intake opening level, so that the suction means with their intake opening level fully on the Bag surface can come to rest. This is also  an adaptation of the device to bags with airtight Sack walls and high inherent rigidity possible.

The suction means can be made from a sheet metal housing that is open on one side with a connecting piece for a connecting line to the suction fan exist, the open side of which forms the suction opening. The term opening plane is preferably a flat surface meant, in the broader sense, can also be the edges of the Intake opening circumscribed opening level, for example, slightly be arched. The suction opening can depend on the Size of the case must be completely open or with which the sack be wall-supporting ribs or a perforated plate. It has been found to have no special sealants the edges of the suction opening are required. In individual cases however, it may be advantageous to use the suction opening of the suction means to be provided with all-round sealing lips.

In connection with the separation of bags is a pair Arrangement of suction means spaced apart along the Sack bottom edge cheap. The two suction means can Elongated holes can be adjusted at a distance to each other to fit different sack widths.

To open the bag opening, for which a low suction and A sufficient holding power can be found in the area of the sack mouth Suction unit in a central arrangement be particularly cheap after the upper wall of the bag has been sucked in, the opening of the bag and thus retraction of spreading vanes in the opening easier. The lower suction means can un indirectly fixed under a sack support surface and be covered with a pinhole. The lower suction means have the advantage in this embodiment that they are when feeding of a sack on the sack support surface due to the permanent Vacuum application a braking effect on the supplied  Exercise the sack and adjust the bottom accordingly pressure can make an end stop edge unnecessary. A exact positioning here is due to the effect of the lower one vacuum devices under constant pressure and / or through a non-contact sensor-monitored bag transport device like a Conveyor belt ensured. The lower suction means can each but also be designed to be movable and a symmetrical counterpart Carry out movement to the upper suction devices. The sack cover The surface is correspondingly when opening a sack to move.

Suitable suction fans, which, as described above, are intended to supply two suction units for receiving a sack and a suction unit for opening the sack, are due to a negative pressure in the range of 20-100 mbar with a delivery volume flow in the range between approximately 4-8 m ³ / min. featured. The pressure curve over the delivery volume flow should run as flatly as possible and react only slightly as a percentage to a change in the volume flow after the bag wall has been sucked in, so that only a few deviations occur during operation from a pair of values at the design point.

Preferred embodiments are described below with reference to Drawings described and explained.

Fig. 1 shows a device for handling bags according to the invention, in which the means for separating the bags are highlighted, in side view;

Fig. 2 shows the means for separating the bags of Figure 1 in plan view.

Fig. 3 shows inventive suction means according to Figures 1 and 2 in front view.

Fig. 4 shows the suction means of Figure 3 in plan view.

Fig. 5 shows the suction means as claimed nevertheless Figures 3 and 4 in vertical section.

Fig. 6 shows an inventive device for handling bags, the means for opening and Aufsprei zen individual bags are highlighted in side view;

Fig. 7 shows the means for opening and spreading according to Fig. 6 in plan view;

Fig. 8 shows inventive suction means according to Figures 6 and 7 in front view.

FIG. 9 shows the suction means according to FIG. 8 in a side view;

Fig. 10 shows the suction means according to Figs. 8 and 9 in plan view.

In Figs. 1 and 2, a device according to the invention is shown, which has a sturdy frame 11 in which a bag magazine is recognizable 12th In this there is a stack of sacks 13 of empty sacks lying flat on top of one another. On a cross member 14 in the frame 11 is a pivot arm 15 in a pivot bearing 16 of the essential horizontal extent angeord net. On a further cross member 17 in the frame 11 pneumatic table cylinders 18 , 19 are articulated, which attack with their Schubstan conditions on an axis of rotation 20 in the swivel arm 15 . By actuating the actuating cylinders 18 , 19 , the pivot arm 15 can be raised and lowered with its free end, as illustrated by a double arrow H ₁ . On the swivel arm 15 stop buffers 22 , 23 are further attached, which limit the movement of the swivel arm 15 upwards by a stop against a further cross member 21 in the frame 11, which is only indicated.

At the front end of the swivel arm 15 , sow means 24 , 25 are arranged, which are fastened to a bridge 26 which are suspended in a head piece 27 in a damped manner via elastic elements 28 , 29 . The suction means 24 , 25 are adjustable on the bridge 26 in the transverse direction, as shown by double arrows Q ₁ , Q ₂ . The head piece 27 is displaceable and retractable via a pneumatic actuating cylinder 30 in a guide carriage 31 by means of two guide rods 32 , 33 , as marked by a second horizontal double arrow V ₁ . The suction means 24 , 25 have suction openings 34 , 35 of rectangular cross-section and height-adjustable stop leads 36 , 37 , which are covered by the bridge 26 in a top view. Furthermore, the suction means 24 , 25 connecting piece 38 , 39 for connecting flexible pressure-resistant lines L ₁ , which are only indicated by a dash-dotted line in the side view. These lines lead from the connecting pieces via a holding piece 40 attached to the bag magazine 12 to a vacuum distributor housing 42 screwed onto the frame 11 . From this leads a line L ₄ to the suction fan, not shown. At the holding piece 40 , a baffle 41 is arranged for a single bag. The suction means 24 , 25 are shown in the two different positions of the pneumatic actuating cylinder 33 , a sack S ₁ , S ₂ which has already been picked up being identified by dash-dotted lines. It can be seen how the sack is rejected in a Z-shape in the area of the sack bottom, which results in stiffening over the entire width. It is easy to understand that when the actuating cylinders 18 , 19 are fully extended, the swivel arm 15 and thus the suction means 24 , 25 with the stop strips 36 , 37 rest on the upper sack in the sack stack 12 . The uppermost sack is grasped and sucked in by the suction openings 34 , 35 in the manner shown.

In the frame 11 , a movable conveyor belt 43 is also shown, which is pivotally mounted at the end, not shown, and can be pivoted from an actuating cylinder 44 from the illustrated lower position into an upper position. Furthermore, a conveyor belt 45 is shown, at the end of which a sack pad 46 can be seen. Above this sack support 46 further suction means 72 are shown as upper swiveling suction means for opening, while sunk in the sack support 46 lower fixed suction means 73 can be seen. This will be discussed in connection with other figures.

In FIGS. 3 to 5, the suction means 24, 25 shown enlarged in Figs. 1 and 2 and provided with the above already designated reference numerals. Reference is hereby made to the description. In addition, it is recognizable that the suction means 24 , 25 have slots 51 , 52 in their housing with which they can be adjusted horizontally relative to the bridge 26 , so that their mutual distance can be changed. It can also be seen that the stop strips 36 , 37 have pairs of elongated holes 53 , 54 , 55 , 56 through which their lower right stop edge can be adjusted in height relative to the intake opening plane 34 , 35 .

In Figs. 6 and 7 the frame 11 in greater detail, in turn, is seen, which are only indicated in FIG. 1. In particular, the conveyor belt 43 - shown here in the upper position - and the conveyor belt 45 , and the bag support 46 , while the pivot arm 16 described with reference to FIGS . 1 and 2 is shown here with its details only indicated. Likewise, a drive motor 47 for the conveyor belts is only indicated with thin lines. Above the conveyor belt 45 and the bag support 46 there is a guide grid 61 with a plurality of bars which are fastened to an axis of rotation 62 which is mounted in the frame 11 in two tabs 63 , 64 . The Git ter 61 is about two actuating cylinders 65 , 66 , which are mounted on a cross member 67 in the frame 11 , from the conveyor belt 45 bar, so that an opening of the left-hand blind opening is not prevented. When driving forward a single sack from the conveyor belt 43 on the conveyor belt 45 to the sack support 46 , the grid 61 is in its lower position shown to prevent e-in automatic lifting of the quickly conveyed sack from the conveyor belt 45 .

Furthermore, a central pivot arm 69 mounted on an axis of rotation 68 is arranged in the frame 11 and can be raised and lowered by means of an actuating cylinder 70 , as indicated by a double arrow V ₂ . The actuating cylinder is articulated on an intermediate floor 71 . At the front end of the swivel arm 69 there are movable upper suction means 72 according to the invention, which cooperate with lower suction means 73 permanently installed in the bag support 46 . The upper suction means 72 are arranged so as to be adjustable by means of fastening tabs 74 , 75 in the swivel arm 69 , as indicated by a double arrow H ₂ . On the upper suction means 72 , a suction opening 76 and a connection piece 77 are recognizable as details. The lower suction means 73 allow a suction opening 78 in the plane of the sack pad 46 and a side connection piece 79 can be seen. The upper suction means 72 finally have a stop guide 80 . When the swivel arm 69 is lowered by means of the actuating cylinder 70 , the stop bar 80 lies on the upper sack wall, the upper sack wall being sucked against the suction opening 76 , so that the sack wall S _{3 is} Z-shaped and stiffening, as with a cord-dotted line Line indicated, rejected. When the swivel arm 69 is raised into the position shown by means of the actuating cylinder 70 , the sack opens, since at the same time the lower sack wall is held in place by the permanently installed lower suction means 73 .

In Fig. 6, a pivot arm 81 is also shown, which is rotatable about a rotating beam 82 and at the end has a pair of expanding blades 83 , 84 which can pivot into the bag opening. The spreading vanes 83 , 84 can then be removed from one another, as a result of which the bag opening is spread and, with the uriter pressure still present, the suction means 76 , 78 of the suction means 72 , 73 are torn away. The bag held by the spreading vanes 83 , 84 can then be moved away with the swivel arm 81 and placed on a bag neck. Starting from the vacuum distributor housing 42 , a partially flexible, partially fixed line L _{2 can be seen} , which leads to the connecting piece 79 of the lower suction means 73 , and a similarly running line L ₃ to the connecting piece 77 of the upper suction means 72 , each of which is indicated by a dash-dotted line Line are marked. The suction fan itself is not shown.

In FIGS. 8 to 10 suction means according to the invention are provided according to FIGS. 6 and 7 shown enlarged and with the above already designated reference numeral 72. Reference is hereby made to the description. Furthermore, it can be seen that the suction means 72 in the mounting tabs 74 , 75 have elongated holes 91 , 92 with which they can be adjusted in the longitudinal direction relative to their swivel arm 69 . It can also be seen that the stop bar 80 has a pair of elongated holes 93 , 94 , through which its lower stop edge in relation to the Ansaugöff opening level 76 is adjustable in height.

Reference list

11

frame

12th

Sack magazine

13

Sack stack

14

Cross member

15

Swivel arm

16

Swivel bearing

17th

Cross member

18th

Actuating cylinder

19th

Actuating cylinder

20th

Axis of rotation

21

Cross member

22

Bumper

23

Bumper

24th

Vacuum cleaner

25th

Vacuum cleaner

26

bridge

27

Headpiece

28

elastic element

29

elastic element

30th

Actuating cylinder

31

Guide carriage

32

Guide rod

33

Guide rod

34

Suction opening

35

Suction opening

36

Stop bar

37

Stop bar

38

Connecting piece

39

Connecting piece

40

Retaining piece

41

Baffle

42

Distributor housing

43

Conveyor belt

44

Actuating cylinder

45

Conveyor belt

46

Bag support

47

Drive motor

51

Long hole

52

Long hole

53

Long hole

54

Long hole

55

Long hole

56

Long hole

61

Guide grille

62

Axis of rotation

63

Tab

64

Tab

65

Actuating cylinder

66

Actuating cylinder

67

Cross member

68

Axis of rotation

69

Swivel arm

70

Actuating cylinder

71

Mezzanine

72

Vacuum cleaner

73

Vacuum cleaner

74

Tab

75

Tab

76

Suction opening

77

Connecting piece

78

Suction opening

79

Connecting piece

80

Stop bar

81

Swivel arm

82

Rotating beam

83

Spreading vane

84

Spreading vane

85

Suction fan

91

Long hole

92

Long hole

93

Long hole

94

Long hole
L ₁

management
L ₂

management
L ₃

management
L ₄

management
S ₁

bag
S ₂

bag
S ₃

Bag wall
H ₁

, H ₂

Pair of arrows
V ₁

, V ₂

Pair of arrows
Q ₁

, Q ₂

Pair of arrows

Claims (19)

1. A method for separating sacks lying flat in a stack ( 13 ), the sacks being detected by means of suction means ( 24 , 25 ) which can be lowered onto the stack ( 13 ) and individually taken up by the lifting means ( 24 , 25 ) and then from the longitudinally movable over the sack stack suction means ( 24 , 25 ), characterized in that the suction means ( 24 , 25 ) when lowering onto the sack stack ( 13 ) are each stopped at an adjustable fixed distance from the top sack. 2. A method for opening individually lying sacks lying on a support, the sacks being detected by means of moving suction means ( 72 , 73 ) which are movable against the sack walls near the sack opening, and by removing the suction means ( 72 , 73 ) open to each other and then led away longitudinally to the base, characterized in that the upper movable suction means ( 72 ) are lowered onto the upper bag wall and are each stopped at an adjustable fixed distance from the upper bag wall. 3. The method according to claim 1 or 2, characterized in that the suction means ( 24 , 25 , 72 , 73 ) are acted upon with a vacuum which is continuously present at least when singling / opening. 4. The method according to claim 1, characterized in that after lifting the suction means ( 24 , 25 ) the singled bag for further transport against the negative pressure of the suction means ( 24 , 25 ) is torn off. 5. The method according to claim 2, characterized in that the opened sack after lifting the upper suction means ( 72 ) when spreading / for further transport against the negative pressure of the suction means ( 72 , 73 ) is torn off. 6. The method according to any one of claims 1 to 5, characterized in that with approximately unchanged power consumption of the suction means ( 24 , 25 , 72 , 73 ) acting blower ( 85 ) build up a vacuum on the suction means ( 24 , 25 , 72 , 73 ) due to the suction of a sack as a control signal for lifting the movable suction means ( 24 , 25 , 72 ) is used ver. 7. The method according to any one of claims 1 to 6, characterized in that the lowering of the movable suction means ( 24 , 25 , 72 ) is terminated by attaching slings on the bag stack ( 13 ) or the bag to be opened. 8. The method according to any one of claims 1 to 7, characterized in that the lowering of the movable suction means ( 24 , 25 , 72 ) by placing a mechanical button on the bag stack ( 13 ) or the bag to be opened by means of one of these triggered Control signal is ended. 9. The method according to any one of claims 1 to 8, characterized in that the lowering of the movable suction means ( 24 , 25 , 72 ) is ended by contactless distance measurement upon detection of a minimum distance from the stack of sacks ( 13 ) or to the sack to be opened. 10. Device for separating flat in a stack ( 13 ) superimposed sacks with the stack ( 13 ) lowerable and from this removable suction means ( 24 , 25 ) with downward-facing suction openings ( 34 , 35 ), characterized in that control means on the suction means ( 24 , 25 ) are provided, which held the suction openings ( 34 , 35 ) of the suction means ( 24 , 25 ) in an adjustable predetermined minimum distance from the surface of the upper sack. 11. Device for opening individually lying flat on a Unterla ge ( 46 ) sacks with at least one lowerable on the sack and liftable from this sack means ( 72 ) with a downward suction opening ( 76 ) and at least one sack lying under the sack ( 73 ) with an upward-pointing suction opening ( 78 ), characterized in that control means are provided on the upper movable suction means ( 72 ) which stop the suction opening ( 76 ) at an adjustable minimum predetermined distance from the upper bag wall. 12. The apparatus of claim 10 or 11, characterized in that the suction means ( 24 , 25 , 72 , 73 ) with a suction fan ( 85 ) are permanently open at least when singling / opening. 13. Device according to one of claims 10 to 12, characterized in that the lower suction means ( 73 ) with their suction opening ( 78 ) lie in the plane of the base ( 46 ) and are firmly arranged. 14. Device according to one of claims 10 to 13, characterized in that a pressure sensor in the suction means ( 24 , 25 , 72 , 73 ) or in the line between the suction means and the suction fan ( 85 ) is arranged, which as a signal transmitter for Stroke movement of the movable suction means ( 24 , 25 , 72 ) is switched. 15. Device according to one of claims 10 to 14, characterized in that the control means from at least one stop bar ( 36 , 37 , 80 ) projecting at right angles to the suction opening ( 34 , 35 , 76 ) on the movable suction means ( 24 , 25 , 72 ) consist. 16. The device according to one of claims 10 to 15, characterized, that the control means comprise a mechanical button. 17. The device according to one of claims 10 to 16, characterized, that the control means a contactless Include sensor. 18. Device according to one of claims 10 to 17, characterized in that the suction means ( 24 , 25 , 72 , 73 ) from a sheet metal housing open on one side with a connecting piece ( 38 , 39 , 77 , 79 ) for a connecting line (L ₁ , L ₂ , L ₃ ) with the suction fan ( 85 ). 19. Device according to one of claims 10 to 18, characterized in that the at least one stop bar ( 36 , 37 , 80 ) via elongated holes ( 53 , 54 , 55 , 56 , 93 , 94 ) adjustable relative to the suction opening plane ( 34 , 35 , 78 ) on the housing of the movable suction means ( 24 ', 25 , 72 ) is arranged.