EP3168163B1 - Bag attachment device - Google Patents

Description

The invention relates to a Sackaufsteckvorrichtung for attaching valve bags on a valve bag filling machine and a method for operating a corresponding Sackaufsteckvorrichtung.

Valve bags for filling free-flowing bulk material are known from the prior art. They are characterized by a valve bag opening for filling via a filling tube of the filling machine, wherein this valve bag opening automatically closes after filling and subsequent removal of the filling tube of the filling machine.

There are various embodiments of valve bag filling machines are known, which is used for a high throughput of valve bags regularly rotating valve bag filling machines. Corresponding filling machines have a plurality of horizontally arranged filling tubes which rotate about a common vertical filling machine axis. During a circulation of a filling tube about the vertical filling machine axis, a valve bag is attached to the filling tube at a first point of the circulation. As the valve bag is subsequently filled, the fill tube moves along with the valve bag and the fully filled valve bag can be withdrawn from the fill tube at a second point in the cycle. Subsequently, the filling tube moves back to the first point of circulation.

For attaching valve bags on the filling tubes of a valve bag filling machine is regularly a Sackaufsteckvorrichtung as they, for example. In EP 2 246 264 A1 is disclosed provided. In a design of this Sackaufsteckvorrichtung be provided as a bag bundle on a receiving position loosely stacked valve bags and folded such that the valve bag opening is opened sufficiently to simply put the valve bag with the valve bag opening on a filling tube of the valve bag filling machine. In the initial state sack bundles usually comprise 12 to 15 valve sacks.

For a high operating speed of the valve bag filling machine - and thus a high throughput of valve bags - it is desirable to rotate the individual filling tubes at a high speed about the vertical filling machine axis. As a result, the Sackaufsteckvorrichtung must be able to attach valve bags on the filling tubes of the valve bag filling machine in rapid succession.

It has been found that often the Sackaufsteckvorrichtung is a limiting factor for the operating speed of a valve bag filling machine. It is less the speed of separation of the valve bags of a bag bundle, the unfolding of the valve bags or the final everthing of the valve bags on the filling tubes of the valve bag filling machine, the limiting factor. Rather, it has been found that the tracking of a new bag bundle on the receiving position after the previous bag bundle is depleted by receiving the last valved bag of the bag bundle from the receiving position, any increase in the operating speed of a valve bag filling machine. Unless it is accepted that regularly when tracking a new bag bundle on the receiving position one or more filling tubes of the valve bag filling machine of Sackaufsteckvorrichtung can not be equipped with valve bags, the time interval between the attachment of two valve bags - the so-called. Takt time - Are chosen sufficiently large, so that at this distance, if necessary, the tracking of a new bag bundle is possible. The working speed of a valve bag filling machine should be selected according to this cycle time.

WO 2013/040717 A1 discloses a Sackaufsteckvorrichtung, in which the position of each individual male valve bag, for example, is optically determined to adjust the Aufsteckbewegung so that the valve bag is securely attached to the filling tube of the valve bag filling machine.

The invention has for its object to provide a Sackaufsteckvorrichtung that allows a comparison with the prior art shorter cycle time.

This object is achieved by a Sackaufsteckvorrichtung according to the main claim. Advantageous developments are the subject of the dependent claims.

Accordingly, the invention relates to a Sackaufsteckvorrichtung for attaching valve bags to a valve bag filling machine, with a valve bag receptacle for receiving the uppermost valve bag of a receiving position lying bag bundle and a transport device for transporting a bag bundle from a waiting position to the receiving position, two connected to a control unit Distance sensors are arranged at a distance from each other, that the thickness of the sack bundle on the receiving position can be determined by the control unit from the predetermined distance between the two distance sensors and the distances detected by the latter, and the control unit is designed to detect, based on the determined thickness of the sack bundle, if only one last valve sack from the bag bundle in the receiving position, wherein the control unit upon detection that only one last valve bag from the bag bundle is in the receiving position acts on the valve bag receiver such that the take-up speed of the last valve bag is accelerated from the receiving position with respect to the receptacle of the preceding valve bags.

1. a) Ermitteln der Dicke des Sackbündels; und
2. b) Feststellen anhand der ermittelten Dicke des Sackbündels, wenn nur noch ein letzter Ventilsack vom Sackbündel in der Aufnahmeposition liegt

wobei bei Feststellung, dass nur noch ein letzter Ventilsack vom Sackbündel in der Aufnahmeposition liegt, die Aufnahme dieses letzten Ventilsacks durch den Ventilsackaufnehmer gegenüber der Aufnahme der vorherigen Ventilsäcke beschleunigt wird.The invention further relates to a method for operating a bag attachment device, in which valve bags of a bag bundle lying in a receiving position are received individually by a valve bag receiver, with the steps:

1. a) determining the thickness of the sack bundle; and
2. b) determining based on the determined thickness of the bag bundle, if only a last valve bag from the bag bundle is in the receiving position

wherein upon detection that only one last valve bag from the sack bundle is in the receiving position, the inclusion of this last valve sack is accelerated by the Valve bag receiver against the inclusion of the previous valve sacks.

The invention has recognized that in the Sackaufsteckvorrichtungen according to the prior art, the reliable detection of whether valve bags are still in the receiving position or whether a new bag bundle must be postponed takes some time. Only if it is guaranteed that actually no valve bag is more in the receiving position, a new bag bundle can be nachgeschoben. If the receiving position is not empty when a new sack bundle is pushed, there is a valve bag jam in the Sackaufsteckvorrichtung, which must be manually removed, which in turn leads to unwanted downtime of the entire arrangement of Sackaufsteckvorrichtung and valve bag filling machine.

In the prior art, the check whether a valve bag is still in the receiving position of the Sackaufsteckvorrichtung often performed via a built-in contact surface of the receiving position light sensor. When the last valve bag of a sack bundle is lifted, no light is reflected from the surface of the valve sack into the light sensor, which basically indicates that the sack bundle is exhausted. In order to avoid the risk of misdetection when the last valve bag of a bag bundle is raised due to adhesion when lifting the penultimate valve bag of a bag bundle by the Valve bag, but then falls back to the receiving position, the signal of the light scanner is considered only when is continuously present for a specified grace period. Only then is a new bag bundle moved from the waiting position to the receiving position.

With the solution according to the invention, it is not only possible to determine when the last valve bag was removed from the receiving position, but rather it is now possible to determine when only one - namely the last - valve bag of a bag bundle, in contrast to the prior art is in the shooting position. As a result, a new sack bundle may be ready shortly after lifting the last one Valve bags are tracked by the receiving position, whereby the achievable cycle time of Sackaufsteckvorrichtung - ie the time between the attachment of two valve bags - in the case of Sackbündelnachführung and - since the cycle time is kept as permanent as possible - can also improve overall. In particular, it is possible to dispense with the mandatory period of grace required for the detection of an empty pickup position in the prior art.

The inventively provided at least two distance sensors, the thickness of the lying in the receiving position bag bundle can be determined. If the distance between the two distance sensors is known, the thickness of the bag bundle essentially corresponds to this distance minus the distances measured by the two distance sensors. Based on the measured thickness of the bag bundle can then be seen whether the bag bundle comprises only the last valve bag. For this purpose, the determined thickness of the sack bundle can be compared with a predetermined limit value, below which it can be assumed that the whereabouts of a single valve sack remain in the receiving position.

Incidentally, it is irrelevant if, during the picking up of the upper valve bag by the valve bag receiver, the thickness of the bag bundle lying on the support position may not be measured correctly because, for example, the distance meter is the distance to the valve bag already received and lifted by the valve bag receiver but does not measure to the topmost bag of the sack bundle. At the latest when the recorded valve bag has passed the distancemeter in question and / or has left the valve bag receiver, the determined thickness corresponds to that of the bag bundle lying on the support position. Determining the thickness of the Sack bundle at the appropriate times is perfectly sufficient for the invention.

According to the invention, upon detection that only one last valve bag from the bag bundle is in the receiving position, the control unit acts on the valve bag receiver such that the receiving speed of the valve bag is accelerated from the receiving position in relation to the receptacle of the preceding valve bags. While in the normal case when receiving the uppermost valve bag of a bag bundle by a valve bag receiver, the valve bag is first raised at low speed to prevent the underlying valve bag of the bag bundle is unnecessarily raised due to adhesion and / or a draft, this is at the last valve bag of a bag bundle no longer required. By recognizing in the invention, when the last valve bag of a sack bundle is received, the lifting of just this valve sack can be accelerated, so that the receiving position is released faster to track a new bag bundle. As a result, the achievable cycle time of Sackaufsteckvorrichtung in the case of Sackbündelnachführung and thus also improve overall.

Preferably, the transport device comprises a servomotor for transporting a bag bundle from a waiting position to the receiving position. Through the appropriate use of a servomotor an instantaneous tracking of a new bag bundle on the pickup position at high speed is possible. This also makes it possible to improve the achievable cycle time of Sackaufsteckvorrichtung in the case of Sackbündelnachführung and thus also overall.

It is particularly preferred if the two distance meters are arranged coaxially. Furthermore, the distance measurers are preferably arranged parallel to the height of a bag bundle lying on the receiving position. By an appropriate arrangement of the two distance meter ensures that the actual height of the bag bundle is measured at a certain point. This offers the advantage that, even with a corrugation of the valve bags in a bag bundle, the thickness of the bag bundle can still be determined with sufficient safety. This is especially true if, despite waviness of the individual valve sacks of a bag bundle, no or only small voids are formed between the valve sacks. But even if it comes to corresponding cavities leaves Nevertheless, it can be reliably detected if only one or the last valve bag is present from the bag bundle lying in the receiving position.

Misalignment can only occur if the last valve bag of a bag bundle has a bubble at the point at which the thickness of the bag bundle is determined, ie there is a cavity between the two layers of the valve bag. In this case, the last valve bag may appear to be so thick that the determined thickness of the bag bundle or the last valve bag is above the predetermined limit, so that it is assumed that the bag bundle comprises more than one valve bag. In this case, the measures described above for increasing the speed of the Sackaufsteckvorrichtung in the case of Sackbündelnachführung not grasp. In the course of experiments, however, it has emerged that a corresponding case only rarely occurs in practice. Because of this, it may then exceptionally be provided for such a case not to equip a single filling tube of the valve bag filling machine in a single circulation with a valve bag, so that the basic operating speed of Sackaufsteckvorrichtung and the valve bag filling machine can be maintained. Compared to the prior art, due to the generally higher possible operating speed of the valve bag filling machine, an overall higher throughput of valve bags can still be achieved, even if a filling tube of the valve bag filling machine for a circulation can not be equipped with a valve bag.

The distance sensors can be sensors which determine a distance based on transit time measurements of electromagnetic, in particular optical, or acoustic signals.

It is preferred if the distance sensors each have a resolution of 0.3 mm or better. As a result, a sufficiently accurate determination of the thickness of a bag bundle is possible.

The Valve bag receiver may comprise at least one, arranged on a vertically movable lifting device vacuum suction bar. If the suction strip is lowered onto a valve bag, the valve bag can be held in place by a negative pressure produced in the suction strip and moved vertically via the lifting device.

To explain the method according to the invention, reference is made to the above statements.

• Figur 1: eine schematische Ansicht einer erfindungsgemäßen Sackaufsteckvorrichtung; und
• Figur 2: eine schematische Darstellung einer bevorzugten erfindungsgemäßen Arbeitsweise der Sackaufsteckvorrichtung gemäß Figur 1.

The invention will now be described by way of example with reference to an advantageous embodiment with reference to the accompanying drawings. Show it:

• FIG. 1 a schematic view of a Sackaufsteckvorrichtung invention; and
• FIG. 2 : a schematic representation of a preferred operation according to the invention the Sackaufsteckvorrichtung according to FIG. 1 ,

In FIG. 1 is a schematic representation of an arrangement of a Sackaufsteckvorrichtung invention 1 together with a valve bag filling machine 50 shown.

The valve bag filling machine 50 has a plurality of horizontally arranged filling tubes 51 which rotate about a common vertical filling machine axis 52. During a circulation of a filling tube 51 about the vertical filling machine axis 52, a valve sack 90 is plugged from the Sackaufsteckvorrichtung 1 on one of the filling tubes 51 at a first point of circulation. While the valve bag is subsequently filled with free-flowing bulk material, in this case cement, fed through the supply line 53 of the valve bag filling machine 50, the one filling tube 51 moves further together with the valve bag and the completely filled valve bag can move at a second point in the circulation from Filling tube 51 are withdrawn by a device designed for this purpose (not shown). Subsequently, the filling tube 51 moves again to the first point of circulation.

For attaching valve sacks 90 to the filling tubes 51 of the valve bag filling machine 50, the bag attachment device 1 is provided. The Sackaufsteckvorrichtung 1 comprises a valve bag receptacle 2, with which the respective uppermost valve bag 90 of a lying on a receiving position 3 bag bundle 91 can be added. In this case, the valve bag receiver 2 comprises a vacuum suction strip 5 arranged on a vertically displaceable lifting device 4. To receive a valve bag 90, the vacuum suction strip 5 is lowered onto the uppermost valve bag 90 of the bag bundle 91. When the vacuum suction strip 5 is raised again, the valve bag is held in place by a vacuum produced in the vacuum suction strip 5 and moved vertically in such a way via the lifting device 4, that it is transferred to the horizontal conveyor 6. In the slip-on device 7, the valve bag 90 can be unfolded so that the valve bag opening is sufficiently opened so that the valve bag 90 with its valve bag opening simply put on a filling tube 51 of the valve bag filling machine 50 to be able to, when the filling tube 51 moves past the Sackaufsteckvorrichtung 1.

In the area of the receiving position 3, two distance sensors 10 are arranged coaxially with one another at a distance from one another such that their common measuring axis 11 is arranged parallel to the height of the bag bundle 91 lying on the receiving position 3. The distance sensors 10 are connected via data lines, not shown, with the control unit 12. By the distance sensor 10 arranged below the bag bundle 91 measuring the distance from the distance sensor 10 to the bottom valve bag 90 in the bag bundle 91, while the other distance sensor 10 measures the distance from the distance sensor 10 to the top valve bag 90 in the bag bundle 91, the control unit 12 can start from the distance between the distance sensors 10 from these detected distances determine the thickness of the bag bundle 91.

The Sackaufsteckvorrichtung 1 further comprises a waiting position 8 for another bag bundle 91. The bag bundle 91 on the waiting position 8 can be moved to the receiving position 3, provided that in the receiving position 3 no valve bag 90 is more. For corresponding tracking of the bag bundle 91 from the waiting position 8 to the receiving position 3, a transport device 9 is provided which has a servomotor 9 'as the drive.

Based on FIG. 2 Now, the preferred operation of the Sackaufsteckvorrichtung 1 and in particular the control by the control unit 12 is explained schematically. In the diagram shown in FIG. 2, the first line corresponds to the height position of the vertically movable lifting device 4, the second line to the thickness of the sack bundle 91 located on the receiving position 3, determined by the distance detected by the distance sensors 10, and the third line the position of the transport device 9 for transporting a further bag bundle 91 from the waiting position 8 to the pickup position 3.

At the time t = t0, the lifting device 4 is at a lower position to receive the uppermost valve bag 10 of the bag bundle 91 on the receiving position 3 by means of the vacuum suction bar 5, in particular so lift. The sack bundle 91 comprises two valve sacks 90 for this second point, for which reason the thickness of the sack bundle 91 ascertained via the distance sensors 10 is still above the predetermined limit value (represented by dashed lines). The transport device 9 is at the time t = t0 in the waiting position.

Subsequently, the vertically movable lifting device 4 is moved so that the uppermost valve bag 90 of the bag bundle 91 is raised to the receiving position 3. In this case, the speed of lifting up to the time t = t1 is slowly increased to avoid that the located below the valve bag 90 to be lifted valve bag 90 due to adhesion or Luftverwirbelungen with raised. Only from the time t = t1, the maximum speed for the vertical movement of the lifting device 4 is reached.

Due to the in FIG. 1 shown arrangement of the distance sensors 10 increases the determined by the control unit 12 as a supposed thickness of the bag bundle 91 value, although the actual thickness of the bag bundle 91 of course does not change accordingly. However, this is not critical for the mode of operation of the device according to the invention or for the method according to the invention.

At the time t = t2 the recorded valve bag 90 is moved sufficiently vertically that it is transferred from the vertically movable lifting device 4 to the horizontal conveyor 6 and passed from this to the slip-on device 7. During this process, the valve bag 90 is moved away from the common measuring axis 11 of the two distance sensors 10 at a time t = t3, as a result of which the thickness of the bag bundle 91 determined by the control unit 12 abruptly changes and again coincides with the actual thickness of the bag bundle 91. Since this determined thickness of the sack bundle 91 is below the threshold shown in dashed lines, the control unit 12 can already determine at this time that only one of the sack bundles 91-namely the last-valve sack 90 lies in the receiving position 3.

If the previously received valve bag 90 is completely transferred to the horizontal conveyor 6 (time t = t4), the lifting device 4 moves downwards again until it comes into contact with the last valve bag 90 remaining on the support position 3 in order to receive it (time t = t5).

Subsequently, the lifting device 4 moves upward again, wherein the speed of the vertical process does not have to be increased slowly. Since the control device 12th has previously found that it is at the now received valve bag 90 is the last valve bag 90 of the present in the receiving position 3 bag bundle 91, there is a risk, an underlying valve bag 90 due to adhesion or the like. to take up, not anymore. As a result, the receptacle of the last valve bag 90 can be accelerated by dispensing with the slow acceleration of the vertically movable lifting device 4.

The determined by the control unit 12 thickness of the bag bundle 91 initially remains constant.

Since it was already known at the time t = t3 that the valve bag 90 received at the time t = t5 was the last sack of the sack bundle 90 in the pickup position 3, the tracking of a new sack bundle 91 from the waiting position 8 can already take place at the time t = t6 be started on the receiving position 3, which is due to the method of the transport device 9 in the third line of the diagram FIG. 2 is readable. Even if the tracking of the new sack bundle 91 is completed only at the time t = t8 and the transport device 9 is then subsequently returned to the starting position (time t = t10), the new sack bundle 91 will already be in the measuring axis at the time t = t7 11 of the distance sensors 10 pushed. As a result, from this point on the value determined by the control unit 12 initially no longer coincides with the actual thickness of the sack bundle 91, which is completely uncritical for the present invention at this point in time.

At time t = t9, the previously recorded valve bag 10 is transferred from the vertically movable lifting device 4 to the horizontal conveyor 6. During the surrender of the Valve bag 10 from the horizontal conveyor 6 to the slip-on 7, the valve bag 90 at time t = t10 out of the measuring axis 11 of the distance sensors 10, which is why from this point on the determined by the control unit 12 thickness of the now new, in the receiving position 3 tracked bag bundle 91 equivalent.

Subsequently, the reception of the individual valve sacks 90 of the sack bundle 91, which is now in the receiving position 3, begins in a manner known from the prior art, until again only two valve sacks 90 of the sack bundle 91 remain. The operation of the Sackaufsteckvorrichtung 1 then runs again as starting from the time t = t0 shown.

Claims (11)

1. Bag attachment device (1) for attaching valve bags (90) to a valve bag filling machine (50) comprising a valve bag pick-up mechanism (2) for picking up the topmost valve bag (90) from a bundle of bags (91) lying at a pick-up position (3), and a transport apparatus (9) for transporting a bundle of bags (91) from a waiting position (8) to the pick-up position (3),
   characterized in that
   two distance sensors (10) connected to a control unit (12) are arranged at a distance from each other in such a way that, from the predefined distance between the two distance sensors (10) and the distances measured by the latter, the thickness of the bundle of bags (91) at the pick-up position (3) can be determined by the control unit (12), and, by using the determined thickness of the bundle of bags (91), the control unit (12) is designed to detect when only a last valve bag (90) from the bundle of bags (91) is lying in the pick-up position (3), wherein, upon detecting that only a last valve bag (90) from the bundle of bags (91) is lying in the pick-up position (3), the control unit (12) acts on the valve bag pick-up mechanism (2) in such a way that the pick-up speed of the last valve bag (90) from the pick-up position is accelerated as compared with the pick-up of the preceding valve bags (90).
2. Bag attachment device according to Claim 1,
   characterized in that
   the transport apparatus (9) comprises a servomotor (9') for transporting a bundle of bags (91) from the waiting position (8) to the pick-up position (3).
3. Bag attachment device according to one of the preceding claims,
   characterized in that
   the two distance meters (10) are arranged coaxially.
4. Bag attachment device according to one of the preceding claims,
   characterized in that
   the distance meters (10) are arranged parallel to the height of a bundle of bags (91) lying on the pick-up position (3).
5. Bag attachment device according to one of the preceding claims,
   characterized in that
   the distance sensors (10) are sensors which determine a distance on the basis of propagation time measurements of electromagnetic, preferably optical, or acoustic signals.
6. Bag attachment device according to one of the preceding claims,
   characterized in that
   the distance sensors (10) have a resolution of 0.3 mm or better.
7. Bag attachment device according to one of the preceding claims,
   characterized in that
   the valve bag pick-up mechanism (2) comprises at least one vacuum sucker bar (5) arranged on a vertically movable lifting apparatus (4).
8. Method for operating a bag attachment device (1) for attaching valve bags (90) to a valve bag filling machine (50),
   the topmost valve bag (90) of a bundle of bags (91) lying in a pick-up position (3) being picked up individually by a valve bag pick-up mechanism (2), characterized by the following steps:

   a) determining the thickness of the bundle of bags (91); and

   b) by using the determined thickness of the bundle of bags (91), detecting when only a last valve bag from the bundle of bags (91) is lying in the pick-up position (3),

   wherein, when it is detected that only a last valve bag (90) from the bundle of bags (91) is lying in the pick-up position (3), the pick-up speed of this last valve bag (90) by the valve bag pick-up mechanism (2) is accelerated as compared with the pick-up speed of the preceding valve bags (90).
9. Method according to Claim 8,
   characterized in that
   detecting whether only a last valve bag (90) from the bundle of bags (91) is lying in the pick-up position (3) is carried out by comparing the determined thickness of the bundle of bags (91) with a predefined limiting value.
10. Method according to Claim 8 or 9,
    characterized in that
    when it is detected that only a last valve bag (90) from the bundle of bags (91) is lying in the pick-up position (3), as the last valve bag (90) is picked up, a new bundle of bags (91) is fed in as soon as the last valve bag (90) has been lifted sufficiently.
11. Method according to one of Claims 8 to 10,
    characterized in that
    the bag attachment device (1) is constructed in accordance with one of Claims 1 to 7.

Images