Bag insertion device with bag lifter and pressure unit for a valve bag filling machine

Abstract

A bag-mounting device for mounting valve bags onto a valve bag filling machine comprises a bag lifter (3) for lifting the valve bag, which is vertically movable between a lower receiving position (I) and an upper staging position (II), a pressure unit (5) with an openable and closeable pressure bar (52) for the received valve bag, and a mounting device (6) for accelerating the valve bag (90) fed from the pressure unit onto a filling nozzle of the filling machine. According to the invention, separate drives are provided for the bag lifter (3) and the pressure unit (5). The drive unit (39) for the bag lifter (5) and the pressure drive (59) are each designed as a position-controlled servo drive. The separate drives with the position-controlled servo drive enhance the motion control, as the individual processes no longer have to occur strictly sequentially, but can overlap variably.Furthermore, the respective speed range can be expanded. The cadence and operational reliability of the machine are increased.

Description

[0001] The invention relates to a bag-mounting device for mounting valve bags onto a valve bag filling machine. It comprises a bag lifter for lifting the valve bag, which is vertically movable between a lower receiving position and an upper provision position, a pressure unit which has a pivotable pressure bar for the valve bag picked up by the bag lifter, and a mounting device for accelerating the opened valve bag towards a filling nozzle of the filling machine.

[0002] Devices for attaching valve bags to the filling nozzle(s) of filling machines are known from the prior art. Valve bags are understood to be sack-shaped packaging containers for free-flowing goods. For filling, they each have a bag valve with an opening through which the free-flowing goods are introduced via the filling nozzle. After filling, the bag valve closes automatically as soon as the filling nozzle is removed, or alternatively, the bag valve is closed by a suitable mechanism.

[0003] To achieve a high throughput on filling machines, it is essential that the valve bags can be separated and applied to the filling machine's filling spout quickly and reliably. To increase filling capacity, such machines often have multiple filling spouts. In a known design, these multiple filling spouts are arranged horizontally and radially outwards in a turret-like configuration. By rotating around a vertical axis, they reach various stages of the filling process, one of which is the station for attaching the valve bag to the respective filling spout. This requires a high cadence from the bag-attaching device.

[0004] In order to take full advantage of this potentially high filling rate of bags, the bag-loading device must be capable of loading the bags at a high rate.

[0005] In a known type of bag-fitting device, the valve bag is picked up by a suction bar, separated, and moved into a staging position. In this staging position, the bag valve is opened. From this staging position, the valve bag is then accelerated towards the filling nozzle by means of a high-speed belt drive and thus fitted into the filling nozzle.

[0006] In the other type, the bag is also picked up and separated using a suction bar. During this picking process, the valve of the valve bag is opened. The valve bag is then moved into a holding position. From this holding position, the valve bag is accelerated towards the filling nozzle and thus attached. The valve bar for picking up the bag and opening its valve is driven by a continuously rotating crank mechanism.

[0007] A disadvantage of existing designs is that increasing the bag-feeding rate to boost throughput requires higher speeds. A higher rate, for example, demands a higher crankshaft rotation speed, leading to increased stress on the crankshaft and its driven components. This can compromise durability and reliability. The alternative would be more robust components made of thicker materials. However, this would make the machines more complex, expensive, and require more installation space.

[0008] The invention is based on the objective of improving a bag attachment device of the type mentioned above in such a way that it enables a higher cadence while avoiding and reducing the aforementioned disadvantages.

[0009] The solution according to the invention lies in the features of the independent claim. Advantageous further developments are the subject of the dependent claims.

[0010] In a bag-mounting device for mounting valve bags onto a valve bag filling machine, comprising as main functional units a bag lifter for lifting the valve bag, which is height-movable between a lower receiving position and an upper supply position, a pressure unit which has an openable and closeable pressure bar for the valve bag picked up by the bag lifter, and a mounting device for accelerating the valve bag fed from the pressure unit with the bag valve open from the supply position onto a filling nozzle of the filling machine, it is provided according to the invention that separate drives are provided for the main functional units of the bag lifter and the pressure unit, a drive unit for the bag lifter and a separate pressure drive for the pressure bar, each designed as a position-controlled servo drive.wherein the position-controlled servo drive, which serves as the drive unit for the bag lifter, is movable between a first and second end position and is coupled to the bag lifter in such a way that the bag lifter is in the receiving position (I) when its drive unit is in the first end position, and is in the provisioning position (II) when its drive unit is in the second end position.

[0011] First, let me explain some of the terms used: The bag lifter is the device used to pick up and separate a valve bag (especially one fed from a stack or roll). It is typically designed to grip and lift the valve bag by its valve, which could also be described as a bag-valve lifter.

[0012] The receiving position is a lower position of the bag lifter, in which the bag lifter receives the supplied valve bag. Typically, this is the uppermost valve bag of a bag bundle; however, this is not limited to that, and a single feed should also be included.

[0013] The provision position is an upper position of the bag lifter, in which the bag lifter provides the raised and opened valve bag so that it can be picked up in the next step, for example to be shot onto the filling tube in the further course.

[0014] Starting from the first end position, with the bag lifter in the receiving position and picking up the valve bag, a cycle begins, which then includes lifting the bag into the provision position with the opening of the valve, as well as subsequently conveying it further and accelerating it to shoot onto the filling tube, and finally the cycle ends with the bag lifter returning to the receiving position, after which a new cycle can begin.

[0015] The position-controlled servo drive for the bag lifter preferably moves back and forth between the first and second end positions. This back-and-forth movement has a reversal point at each end position, where the direction of movement is reversed. Therefore, this back-and-forth movement is to be distinguished from a continuous motion, such as that of a shaft rotating in one direction. The same preferably applies to the pressure drive.

[0016] The invention utilizes the understanding that, thanks to separate drives—one for the bag lifter and one for the pressure unit—in combination with the design of both drives as position-controlled servo drives, a higher cadence can be achieved. Because of the separate drives, mechanical coupling is unnecessary, thus eliminating the required moving components, their mass, and the associated space requirements. Furthermore, the separate drives with position-controlled servo drives increase the freedom of motion control, as the individual processes no longer have to proceed strictly in a (mechanically) predetermined sequence but can overlap, potentially in a variable manner.It is therefore an overlapping motion control system, which can be executed synchronously ("synchronous motion control") or asynchronously ("asynchronous motion control") – this differs from conventional sequential motion control. The motion control system implemented in this way can also include stops and / or waiting or rest periods.

[0017] All of this enables more efficient utilization of the respective cycle times, especially when the drive unit for the bag lifter and the pressure unit are actuated (at least partially) in an overlapping manner. Finally, the separate drives, with the resulting elimination of a mechanical coupling, allow for a simplification of the mechanical design. The entire construction becomes simpler, lighter (and thus more suitable for higher cadence), and, thanks to fewer components, less service-intensive and easier to maintain. Overall, the invention thus combines the advantages of higher cadence with reduced operating costs.

[0018] Furthermore, the position-controlled servo drive enables a wider speed range than conventional mechanically coupled drive designs. This allows for the rapid lifting of the valve bag and targeted approach to the staging position to be easily combined with a particularly slow approach to the receiving position for safe handling, without the need for separate, complex additional mechanisms. This is achieved thanks to the invention through separate drives with the position-controlled servo drive for the bag lifter.

[0019] Equipping the pressure drive with a position-controlled servo drive allows it to be moved at different speeds, and the type of movement, particularly during the pressing action, can be more finely resolved. Furthermore, it has proven advantageous to execute the final section of the pressing action by means of a separate, short movement of the pressure bar. Such a movement pattern can be performed quickly and reliably using the separate drives according to the invention, which are implemented as position-controlled servo drives.

[0020] The servo drive is preferably designed with speed control.

[0021] Advantageously, the electronic control is designed such that at least one of the end positions is reached at a reduced speed, lower than the speed during the lifting of the valve bag. This targeted reduction in speed before reaching the end positions necessitates higher speeds in the intermediate range. In this way, high reliability and operational safety can be combined with an increased cadence, without increasing the load on the components, particularly during hard braking.

[0022] Lifting the bag lifter tightens the bag and typically opens the bag valve. The open state of the valve bag indicates that the bag is open. An additional, separate working position may optionally be provided for opening the bag valve.

[0023] In the transport direction of the valve bag, a pressure unit is provided between the bag lifter and the attachment device. This unit has at least one pressure bar that can be opened and closed for the open valve bag. Actuated by the pressure drive, this pressure bar is open when the bag lifter raises the valve bag to the height of the staging position. The pressure bar is then moved towards the valve bag and, in the closed position, secures the valve bag, preferably by pressing it against a counter element. The pressure bar is advantageously arranged so that, in the closed position, it acts on the valve bag at a point below the bag valve. This clamps the valve bag, opening the valve. The valve bag is then ready to be ejected onto the filling nozzle and can be ejected directly or via an intermediate station, preferably by a belt drive.It should be noted that the pressure bar can also be opened or closed and swiveled in by a linear movement or a pivoting movement.

[0024] Thanks to the position-controlled servo drive, the invention can optionally provide that the open valve bag can be held in a waiting position by extending the stop time in the ready position. Advantageously, an adjustment device for the waiting time in the waiting position can be provided as an option. A short waiting time allows for fine-tuning to improve synchronization. In this way, picking up and positioning the valve bag can be carried out with a certain time buffer to compensate for any unavoidable deviations in bag picking.Furthermore, this method can optionally improve the synchronization between lifting the bag and its launching by means of the launching device, which is particularly advantageous for adapting to different bag types or for synchronizing the various components of the bag launching device, thereby enabling higher cadences while maintaining high operational reliability.

[0025] The servo drive is advantageously implemented with a synchronous servo motor. The synchronous servo motor has the special characteristic that it runs synchronously with the frequency of its supply current. This allows not only precise position control but also precise speed control. For closely timed, partially overlapping actuation, this can be a significant advantage, allowing for higher cadences with high operational reliability. However, the possibility of using an asynchronous motor should not be ruled out.

[0026] Motorized adjustment of the pressure drive is not mandatory; pneumatic actuation can also be used. Pneumatic actuation requires less effort and may suffice for simpler or smaller applications with lower cadence requirements.

[0027] Preferably, an electronic synchronization unit is provided, which is designed for electronically controlled synchronization of the drive unit of the bag lifter and the actuation of the pressure unit. Such synchronization allows, in particular, the reliable and rapid control of overlapping operation between the bag lifter and the pressure unit. Compared to mechanical synchronization, electronic synchronization offers the advantage of greater degrees of freedom for the respective drives. With the electronic synchronization unit, a high degree of overlap can be reliably achieved and operated, thus increasing both the cadence and operational reliability. This is especially true when the electronic synchronization unit is combined with a synchronous servo motor as the drive. However, this is not mandatory; the electronic synchronization unit can also be used, if necessary, to...Optionally, the operator may be trained to operate the drive unit for the bag lifter in at least one start / stop mode for simplification purposes.

[0028] Advantageously, the electronic synchronization unit is designed to incorporate a single, common electronic guide axis for synchronization. This electronic guide axis forms the basis from which the actuation or movement of the bag lifter, the pressure unit, and, if applicable, the attachment device are derived. Specifically, it is designed to derive both the actuation of the pressure drive and a speed profile for the bag lifter drive from this single (common) electronic guide axis, whereby the speed profile can be variable and / or predefined. Such a speed profile can be applied as a setting to the drive unit of the bag lifter and / or the pressure drive. In this way, the speed can be directly controlled, thanks to the common electronic guide axis, in accordance with the actuation of the other components.

[0029] The common electronic guide axis can be a virtual guide axis that has no correspondence to a structural element of the bag fitting device, or it can be a real-oriented electronic guide axis. "Real-oriented" in this context means that this guide axis references a real physical quantity of a structural element of the bag fitting device (for example, referring to valve lift or the position of the pressure bar).

[0030] In a further improved version, not only a speed profile is derived, but also an acceleration profile for the drive unit of the bag lifter and / or the pressure drive. This allows for more precise control, enabling further increases in cadence.

[0031] In particular, independent motion profiles can be implemented in the electronic synchronization unit for the drive unit of the bag lifter and the pressure drive, which preferably overlap at least partially. This allows for a shorter cycle time. It follows that further overlap can also lead to a further increase in the cadence.

[0032] Preferably, the respective positions of the first and / or second end positions can be changed by means of an electronic adjustment device. This allows the height at which the valve bag is to be picked up by the bag lifter to be set using the first end position. If, for example, the valve bags are supplied as bundles, this enables more precise adjustment to different heights, particularly of the individual bundle from which the valve bag is taken. Furthermore, the lifting height of the bag lifter for the valve bag can be changed accordingly, especially by adjusting the second end position. This advantageously allows the degree of opening of the bag valve to be adjusted by changing the lifting height.Advantageously, an additional control unit for the drive unit of the bag lifter can be provided and designed so that the bag lifter approaches the second end position with a special speed profile designed to open the bag valve.

[0033] According to a particularly advantageous embodiment, the drive unit of the bag lifter is designed as a direct drive. This enables a compact design, allowing for more direct and precise control of the bag lifter. Complications such as those that can arise from mechanical transmission linkages or gears, which can lead to adjustment inaccuracies, higher moving masses and thus to dynamic disadvantages or even to dynamically detrimental imbalances, are avoided by the direct drive.

[0034] The bag lifter typically has at least one suction bar for lifting the valve bag. This bar is typically further designed to grip and lift the valve bag by its valve. Advantageously, a second suction bar can be provided in a separate position, enabling safer and more reliable handling of valve bags that are difficult to handle, especially large ones or those of lower quality. This second suction bar can be designed as a bottom lifter, additionally gripping the valve bag by its base.

[0035] A pendulum rocker drive can be advantageously provided for the pressure unit. This allows for a kinematically efficient implementation of the required pivoting movement of the pressure bar.

[0036] Preferably, the openable and closeable pressure bar is mounted on a pressure arm, which is preferably offset from the pendulum element and the bag lifter. This allows for a shorter pressure arm than with a coaxial arrangement, resulting in a narrower design and thus increasing the compactness of the bag-lifting device. Offset here refers to an offset between the rotation axis of the pressure arm and the drive axis of the bag lifter. This results in an overall more compact and less complex design with shorter and optimized movements. Due to the smaller amplitudes, this places lower demands on the material, thereby increasing wear resistance and allowing for higher speeds and thus a higher cadence.

[0037] Advantageously, the ejection device includes a feed mechanism designed to move the valve bag from its staging position to the ejection device. The open valve bag is thus advanced into a firing position. Optionally, this allows for a further waiting position before the valve bag is finally ejected. This enables the open valve bag to be advanced from its staging position at a suitable time, and then accelerated from the firing position to the filling nozzle at a suitable time. For this purpose, the ejection device preferably includes an acceleration unit designed to grip the valve bag with the valve open and accelerate it to eject it onto the filling nozzle. This allows for finer synchronization of the ejection process with the movement of the filling nozzle.

[0038] Optionally, the pressure bar can also be designed in two parts, with a first part being pivotable as described and a second part, following in the transport direction of the valve bag, being rigidly arranged. This improves the guidance of the valve bag. Furthermore, a waiting position can be created in the area of ​​the rigidly arranged part. This offers additional adjustment options for synchronizing the bag attachment device with the filling nozzle of the filling machine.

[0039] It is advantageous if the feed mechanism and the acceleration unit are designed as a combined unit, particularly as a common belt drive. This results in a compact design, with reliable transport and acceleration for injection onto the filling nozzle.

[0040] The invention is explained in more detail below with reference to the accompanying drawing and an exemplary embodiment. The drawing shows: Fig. 1 a schematic view of a bag-loading device according to an embodiment of the invention; Fig. 2 a perspective view of the bag lifter and a pressure unit with the pressure bar open from a front oblique angle; Fig. 3 a perspective view of the bag lifter and a pressure unit with the pressure bar open from a rear oblique angle; Fig. 4 a schematic view of a lifting arm of a bag lifter showing its receiving and staging positions; Fig. 5A-E a phase diagram showing successive phases during the receiving and opening of the valve bag in one embodiment; Fig. 6A-E a top view of the loading device with the pressure bar swung in or out; and Fig. 7 a schematic representation of the synchronization with a guide axis.

[0041] The exemplary embodiment of a bag mounting device for valve bags 90 according to the invention, designated in its entirety by reference numeral 1, is described in Fig. 1 schematically depicted together with a filling machine 8.

[0042] The filling machine 8 is supplied with free-flowing material via a feed pipe 85, which is to be filled into the valve bags 90. The filling machine 8 comprises a plurality of filling nozzles 81, which are arranged radially outwards on a drum 82 rotating about a vertical axis 80. This results in a turret-like arrangement of the filling nozzles 81. As the drum 82 rotates, the filling nozzles 81 reach various stations of the filling process. One of these stations is the station for attaching the valve bag 90 by means of the bag-attachment device 1. Here, the valve bag 90 is attached at the correct time to the filling nozzle 81 that points towards the bag-attachment device 1.

[0043] The bag-loading device 1 has a valve bag feeder 20, through which a bundle 92 of valve bags 90 are fed to the bag-loading device 1. The bundle 92 is typically a stack of valve bags 90, on top of which an uppermost valve bag 91 is freely accessible. The bag-loading device 1 includes a bag lifter 3, with which the uppermost valve bag 91 can be picked up from the bundle 92 and brought vertically upwards, whereby the valve bag transitions into a hanging position and a valve 93 on the top of the now separated valve bag 90 can be opened. Downstream of the bag lifter 3 is a pressure unit 5, which takes the valve bag 90 with the now open valve 93 from the bag lifter 3 and places it in a waiting position in order to shoot it onto one of the filling nozzles 81 of the filling machine 8 at a suitable time by means of a loading device 6.The structure and function of the respective facilities are explained in more detail below.

[0044] For the description of the sack lifter, particular reference will now be made to the following: Fig. 2 und Fig. 3 The bag lifter 3 for picking up and separating the valve bags 90 from a bundle 92 has a lifting arm 31 which is rotatably mounted about a pivot axis 30. In the illustrated embodiment, it is actuated by a drive unit 39, which is designed as a direct drive. The lifting arm 31 describes an arc-shaped movement about the pivot axis 30. One end of the lifting arm 31 is mounted on this pivot axis 30. At the other, free end of the lifting arm 31, a suction bar 35 with several pneumatically actuated suction cups is arranged. The angular orientation of the suction bar 35 with the suction cups is kept constant by means of a stabilizing device 36, so that the suction cups of the suction bar 35 always point downwards, regardless of the pivot position of the lifting arm 31. This ensures a secure gripping and holding of the respective valve bag.

[0045] In the illustrated embodiment, the drive unit 39 is designed as a direct drive with a position-controlled servo drive, in particular a synchronous servo motor, to actuate the bag lifter 3 with its lifting arm 31. This ensures a compact and mechanically rigid design, enabling optimal control of the bag lifter even at high speeds and accelerations, as required to achieve a high cadence of bag picking up and placing onto the filling machine 8.

[0046] The drive unit 39 with the position-controlled synchronous servomotor has a range of motion between a first end position 47, in which the bag lifter 3 with its lifting arm 31 is in a receiving position I for receiving the uppermost valve bag from a bag bundle 92, and a second end position 48, in which the bag lifter 3 with its lifting arm 31 holds the received valve bag 93 raised in a storage position II. The end positions 47, 48 are shown in the schematic representation in the phase diagram according to Fig. 5A-E The physical position assumed by the lifting arm 31 in the respective end positions 47, 48, with the receiving position I and the provisioning position II respectively, are shown schematically in Fig. 4 The lifting arm 31 can be pivoted by an angular range α between the receiving position I and the provisioning position II.

[0047] In the recording position (Position I, see also Fig. 5B und 5D ) the intake manifold 35 is at its lowest point, ready to receive the uppermost valve bag 91. In the provision position (position II, see also Fig. 5C, E) In the figure where the intake manifold 35 is in its upper position, the valve bag 90 hangs vertically downwards from its valve 93. An intermediate position is shown for clarity in Fig. 2 und Fig. 3 shown, in which the bag valve 93 held by the intake bar 35 and a part of the valve bag 90 hanging from it are shown.

[0048] To adjust the position of the end positions 47, 48, an adjustment device 46 is provided on the drive unit 39. This device is designed to set the position of the end positions 47, 48. The lifting height of the bag lifter 3, and thus the opening degree of the bag valve 93, can also be adjusted via this device.

[0049] The bag lifter 3 is arranged in a housing 25, at the front of which the drive unit 39 is located. The housing 25 has a side cover 27 in its upper region to stiffen the overall assembly. A pressure unit 5, which is explained below, is also arranged on the side of the shortened side cover 27.

[0050] The pressure unit 5 is arranged adjacent to the bag lifter 3 and comprises a pressure bar 52, which is arranged at a free end of a pressure arm 51. The pressure arm 51 is pivotally mounted about a pressure axis 50. This axis is offset, preferably parallel, to the pivot axis 30 of the bag lifter 3. The pressure bar 52 is equipped with a plurality of rollers 53 (see figure). Fig. 6A-E ) provided with rollers arranged horizontally next to each other. In the closed state, the rollers 53 work together with a counter bar 56 (see figure). Fig. 2 and Fig. 5A-E ), which is located in the area of ​​the bag lifter 3 at the provision position. In the open state, the pressure arm 51 is pivoted outwards, so that the pressure bar 52 with its rollers 53 is spaced apart from the counter bar 56. This open state is in Fig. 2 und 3 This enables the bag lifter 3 to lift the valve bag 90 to be picked up and bring it into the ready position, so that the valve bag 90 rests laterally against the counter bar 56. - By means of a pressure drive 59, which acts on the pressure axis 50, the pressure arm 51 is pivoted in such a way that the pressure bar 52 with its rollers 53 is guided to the counter bar 56 until the rollers 53 rest there and thereby clamp the lifted valve bag 90 in the ready position in an area immediately below the bag valve 93. This closed state of the pressure arm 51 is in Fig. 5A , C, E shown. By means of a feed device 57, which in the illustrated embodiment is formed by a belt drive 67 with a drive motor (not shown), the valve bag 90 thus provided can be transported to the mounting device 6.

[0051] The mounting device 6 comprises a static roller strip 62 as a stationary extension of the movable pressure bar 52. The roller strip 62 has a further set of rollers 63 and interacts with the belt drive 67, which is driven rapidly by the drive motor (not shown). The static roller strip 62 and the belt drive 67 work together to form an acceleration device 60, which grips the valve bag 90 introduced by the feed device 57 and accelerates it toward the filling nozzle 81 of the filling machine 8, thus mounting it ("shooting it on"). The shared belt drive 67 allows the feed device 57 and the acceleration unit 60 to be designed as a combined unit, saving space and simplifying the design.

[0052] In the illustrated embodiment, the pressure drive 59, like the drive unit 39, is designed as a position-controlled servo drive. It is a direct drive and acts directly on the shaft of the pressure axis 50. However, this design of the pressure drive 59 is not mandatory. The pressure drive 59 can be motorized (possibly with a simpler servo drive or a pure DC or AC motor). The latter allows for a simpler and less complex construction, but only permits less precise control, which can lead to overlap with the actuation of the drive unit 39 of the bag lifter 3.

[0053] The various components and drives of the bag-lifting device 1 are controlled by a controller 7. This controller includes, in particular, a controller 73 for the drive 39 of the bag lifter 3 and a controller 75 for the drive 59 of the pressure unit 5. An electronic synchronization unit 71 is provided for coordinated, synchronized actuation of the bag lifter 3 and the pressure unit 5. Compared to mechanical synchronization, this offers the advantage of greater degrees of freedom for the actuation with regard to timing, amplitude, and speed of the respective drives. In particular, an overlap between the actuation of the bag lifter 3 and the pressure arm 51 is possible. Thus, the pressure arm 51 can already begin its pivoting motion while the bag lifter 3 is still moving to the staging position II, thereby shortening the cycle time.Furthermore, fine-tuning for the pivoting of the lifting arm 51 can also be provided such that the final part of the movement only occurs when the valve bag is to be accelerated and ejected onto the filling nozzle. This fine-tuning can include a short waiting period for better synchronization, thereby achieving more precise acceleration and attachment of the valve bag 90. This is a significant advantage of the separate drive of the pressure unit 5. Furthermore, the increased operational reliability achieved in this way allows for an increase in the cadence.

[0054] The implementation of an electronic guide axis 72 in the electronic control unit 71 is particularly advantageous, specifically as a "virtual guide axis" that has no corresponding physical element. From this single, shared electronic guide axis 72, both the actuation of the drive of the pressure unit 5 and a speed profile of the drive unit 39 for the bag lifter 3 can be derived. The latter is configured as a specification for the drive unit 39 of the bag lifter 3. In this way, its speed can be directly controlled, thanks to the electronic, and in this case virtual, guide axis 72, in accordance with the actuation of the other components, especially the pressure unit 5 with the pivoting of the pressure bar 52. This allows for increased parallelism of the processes through greater overlap, which reduces the cycle time and thus permits a further increase in the cadence.In a further improved version, not only is a speed profile derived, but also an acceleration profile for the drive unit 39 of the bag lifter 3. Optionally, a speed and, if applicable, acceleration profile can also be provided for the separate pressure drive 59 of the pressure unit 5, especially if this is also equipped with a synchronous servo motor.

[0055] The control unit 7 with its synchronizing unit 71 is further designed to coordinate the actuation of the mounting device 6 with the movement of the filling nozzle 81. The mounting device 6 is actuated to accelerate the provided valve bag 90 with open valve 93 precisely when the valve bag 90, accelerated by the acceleration unit 60, can be shot with pinpoint accuracy onto the filling nozzle 81, which at that moment rotates into the position in front of the bag mounting device 1.

[0056] The operation of the various components, in particular the bag lifter 3 with the lifting arm 31 and the rocker arm 51 of the pressure device 5, is explained below with reference to a phase diagram, as shown in the Fig. 5A-6E is included. Accordingly, the Fig. 6A-E A schematic top view showing the position of the pressure arm 51 with its roller bar 52 and rollers 53. The static roller bar 62 with its further roller set 63 and the belt drive 67 interacting with it are also visible.

[0057] This is explained using the example of a variant of the embodiment in which the drive motors 39, 59 are not directly mounted on the respective axes 30 and 50, but the axes 30, 50 are driven indirectly by the respective drive motors 39, 59 by means of pendulum arms. One pendulum arm 4 connects the drive motor 39 to the lifting arm 31 and comprises a pendulum element 41, which is rotatable about a pivot axis 40, as well as a connecting rod 43 connecting the pendulum element 41 to the lifting arm 31. In this variant, the first end position 47 and the second end position 48 are also shown, as well as an optional additional second end position 48'. The other pendulum swing arm connects the pressure drive 59 with the lifting arm 51 and includes a lifting pendulum element 54 rotatably mounted about an auxiliary axis 58 and a lifting rod 55 that connects the lifting pendulum element 54 with the lifting arm 51.

[0058] In Fig. 5A Figure 1 shows a starting position in which a bundle of bags with an uppermost valve bag 91 is located below the lifting arm 31. The pendulum element 41 is in the second end position 48, in which the lifting arm 31 of the bag lifter, actuated via the drive rod 43, is in its upper position, the provision position II. In the illustrated situation, the pressure rocker 51 is pivoted so that the rollers 53 bear against the counter bar 56, which in this embodiment is formed by a rear section of the belt drive 67, as shown. Fig. 6A Figure 1 shows. It should be noted that in the embodiment shown here, optional additional bottom lifters 37 are provided for the valve bag, each having an additional suction cup 38. This suction cup is designed to grip the bottom 94 of a valve bag 91 located at the top of the bundle 92.

[0059] In Fig. 5B Figure 1 depicts a situation in which the pendulum element 41 is in its first end position 47, causing the lifting arm 31, actuated via the drive rod 43, to reach its lower receiving position I. In this position, the lifting arm 31, with its suction bar 35, grasps the drain valve 93 in the upper area of ​​the drain bag 91. The optional bottom lifter 37 is also extended and, with its additional suction cup 38, grips the bottom 94 of the drain bag 91. The pressure arm 51 is open, as is also Fig. 6B This indicates that the uppermost valve bag 91 can be moved into the provision position. In this position of the pendulum element 41 in its first end position 47, the movement speed of the lifting arm 31 is minimized, so that gentle and safe pickup of the valve bag by means of the suction bar 35 is achieved.

[0060] During the further movement of the pendulum element 41, it reaches, as in Fig. 5C Finally, the optional additional second end position 48' is shown. During this movement, the lifting arm 31, actuated via the connecting rod 43, performs an upward movement, lifting the valve bag by both the suction bar 35 and the floor lifter 37. These are designed to grasp the uppermost valve bag 91 of the bundle 92 at its top, with the valve 93 located there. The lifting arm 31 then swings upward, actuated by the connecting rod 43, lifting the valve bag. The valve bag is then fully raised until (after being released from the floor lifter 37) it hangs vertically downwards when the lifting arm 31 reaches its upper end position. This lifting action tightens the valve bag 90 and opens the valve 93.

[0061] When the pendulum element 41 reaches its second end position 48' and thus the valve bag has reached its provision position II, the pressure rocker 51 is closed. This is in Fig. 6C The valve bag 90 is thus ready to be transported to the mounting device 6 with its static roller strip 62 and belt drive 67 for injection onto one of the filling nozzles 81 of the filling machine 8 (in Fig. 5, 6 (not shown).

[0062] The following moves, as in Fig. 5D As shown, the pendulum element 41 continues to move and reaches the first end position 47, whereby the lifting arm 31 returns to its lower receiving position I. The suction bar 35 then engages the valve 93 in the upper area of ​​the valve bag, and the bottom lifter 37 engages the bottom 94 of the valve bag. Again, the movement speed of the lifting arm 31 in this position is minimal to ensure gentle and secure handling of the valve bag. To create space for lifting the valve bag, the pressure arm 51 with its rollers 53 is swung out, as also shown in Fig. 6D depicted.

[0063] In the representation according to Fig. 5E The pendulum element 41 finally reaches the second end position 48 again. The valve bag is raised sufficiently to reach its upper provision position II. The pressure rocker 51 is closed, as in Fig. 6E As shown. The cycle is completed upon reaching this second end position 48. A further cycle can now be carried out by taking in additional valve bags from bundle 92.

[0064] The coordinated actuation of the drive unit 39 of the bag lifter 3 and the pressure drive 59, effected by the electronic synchronizing unit 71 via its guide axis 72, is shown in a diagram-like representation in Fig. 7 shown. The diagram there shows the movement controlled by the electronic synchronizing unit 71. The electronic synchronizing unit 71, with its virtual guide axis 72, specifies a certain behavior for the lifting arm 31 and the position of the pressure bar 52, depending on the angle of the virtual guide axis over time. In Fig. 7For one cycle, a normalized position of the lifting arm 31 is represented by a solid line across the angle of the virtual guide axis 72. The normalized position of the lifting arm 31 is shown on the left ordinate, normalized to the range from 0% bottom to 100% top on the left ordinate. Similarly, the normalized position of the pressure bar 52 is shown with a dotted line, relative to the right ordinate and also normalized to the range from 0% bottom to 100% top. Not only is the respective normalized position specified, but the slope of each line also specifies the corresponding speed at which the drive unit 39 of the bag lifter actuates the lifting arm 31, or at which the pressure drive 59 moves the pressure bar 52.

[0065] It can be seen that at the beginning of the cycle, the lifting arm 31 leaves its 100% position and moves linearly downwards to the 0% position. Simultaneously, the pressure bar 52 also moves at the start. Due to the steeper slope of the dotted line, it can be seen that the pressure bar 52 is actuated at a higher speed and reaches its 100% position more quickly. It remains there, while the lifting arm continues to actuate at a lower speed and finally reaches its 0% position. In this respect, an overlapping operation takes place, which is time-saving compared to a classic sequential operation. According to the virtual guide axis 72, the lifting arm 31 then briefly remains in the 0% position, and the process then runs in reverse, again with time-saving overlapping actuation.

[0066] The diagram shows that position and speed are determined or derived from the electronic virtual guide axis. This can be optimally used for one or more overlaps, whereby, thanks to this precise control via the virtual guide axis, 72 actuation processes can be nested within each other in a time-saving manner. This results in a reduction of the cycle time and thus enables an increase in cadence while ensuring high operational reliability.

Claims

1. Bag mounting device for mounting valve bags onto a valve bag filling machine, comprising as main functional units a bag lifter (3) for lifting the valve bag, which is vertically movable between a receiving position (I) at the bottom and a provision position (II) at the top, a pressure unit (5) which has an openable and closeable pressure bar (52) for the valve bag (90) received by the bag lifter, and a mounting device (6) for accelerating the valve bag (90) with open bag valve supplied from the pressure unit (5) onto a filling nozzle (81) of the filling machine (8), characterized by the fact thatSeparate drives are provided for the main functional units of the bag lifter (3) and the pressure unit (5), a drive unit (39) for the bag lifter (3) and a separate pressure drive (59) for the pressure bar, wherein the drive unit (39) for the bag lifter (3) and the pressure drive (59) are each designed as a position-controlled servo drive, wherein the position-controlled servo drive acting as the drive unit for the bag lifter is movable between a first and second end position (47, 48) and is coupled to the bag lifter (3) in such a way that the bag lifter (3) is in the receiving position (I) when its drive unit is in the first end position (47), and is in the provision position (II) when its drive unit is in the second end position (48).

2. Bag mounting device according to claim 1, characterized by the fact that the drive unit (39) for the bag lifter (3) and the pressure drive (59) are operated in an overlapping manner.

3. Bag mounting device according to claim 1 or 2, characterized by the fact that The position-controlled servo drive is implemented with a synchronous servo motor.

4. Bag mounting device according to one of the preceding claims, characterized by the fact that an electronic synchronizing unit (71) is provided which is designed for electronically controlled synchronization of the drive unit of the bag lifter and the actuation of the pressure unit (5).

5. Bag attachment device according to the preceding claim, characterized by the fact that For synchronization, a single common electronic guide axis is implemented in the synchronizing unit (71).

6. Bag attachment device according to the preceding claim, characterized by the fact thatthe common electronic guide axis is a virtual guide axis that has no correspondence to a structural element of the bag fitting device, or a real-oriented electronic guide axis that references a real physical quantity of a structural element of the bag fitting device.

7. Bag mounting device according to the preceding claim, characterized by the fact that the electronic synchronizing unit (71) is further designed to derive from the one common electronic guide axis both the actuation of the pressure drive and a speed profile of the lifting drive, which is applied as a specification to the lifting drive, wherein the speed profile is variable and / or predefinable, and preferably also an acceleration profile.

8. Bag attachment device according to the preceding claim, characterized by the fact thatthe electronic synchronizing unit (71) is further designed to derive a speed profile for the pressure drive and to apply it as a specification to the pressure drive, wherein the speed profile is variable and / or predefinable, and preferably also an acceleration profile.

9. Bag attachment device according to one of claims 4 to 8, characterized by the fact that Independent motion profiles are provided for the drive unit (39) for the bag lifter (3) and the pressure drive (59), which preferably overlap at least partially.

10. Bag attachment device according to one of the preceding claims, characterized by the fact that an electronic adjustment device (46) is provided by means of which the position of the first and / or second end position (47, 48) can be changed so that the receiving height and / or lifting height of the bag lifter (3) for the valve bag (90) is changed accordingly.

11. Bag attachment device according to one of the preceding claims, characterized by the fact that an additional control (74) for the drive unit of the bag lifter (39) is provided and is designed such that the bag lifter approaches the second end position (48) with a special speed profile designed to open the bag valve (93).

12. Bag attachment device according to one of the preceding claims, characterized by the fact that The drive unit of the bag lifter is designed as a direct drive.

13. Bag attachment device according to one of the preceding claims, characterized by the fact that the pivotable pressure bar (52) is provided on a pressure rocker (51), which is preferably offset axially to the pendulum element (41) and the bag lifter (3).

14. Bag attachment device according to one of the preceding claims, characterized by the fact that a feed device (57) is provided which is designed to move the valve bag towards the mounting device (6).

15. Bag attachment device according to one of the preceding claims, characterized by the fact that the attachment device (6) has an acceleration unit (60) which is designed to capture the valve bag (90) with the valve open and accelerate it to shoot onto the filling nozzle (81).

16. Bag mounting device according to claims 14 and 15, characterized by the fact that the feed device (57) and the acceleration unit (60) are designed as a combined unit, in particular as a common belt drive (67) .

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