The present application claims priority under 35 U.S.C. § 119(a) of European Patent Application No. 17154247.5 filed Feb. 1, 2017, the disclosure of which is expressly incorporated by reference herein in its entirety.
The present invention relates to a device for transporting and filling bags, preferably open bags, comprising a filling device, which is rotatable about an axis of rotation, having multiple filling openings distributed over the circumference of the filling device, and also comprising a feeder, using which an empty bag can be fed to a filling opening, wherein the feeder comprises at least one holding unit for a bag which is movable normally to the axis of rotation of the filling device.
Various devices for transporting and filling bags are known from the prior art. These devices are also used, inter alia, when filling open bags with bulk material. To increase the throughput, such devices are often embodied as rotatable, wherein fixing units, which are used for fastening the bags around the filling openings (for example, on a filling nozzle) or below the filling openings are arranged so they are rotatable about a rotating column. Empty bags are conveyed from the feeder to the filling device and accepted thereby. After the fastening of the bags to the filling openings by the fixing units, the bags are filled and transported further by rotation of the filling device, until they are removed from the filling device again by a bag removal unit (bag remover).
To avoid a cyclic operating mode of such devices, i.e., for example, stopping the filling device to feed a bag and/or to remove a bag, feeders are known which move in some sections with the filling device, so that the filling device can maintain a consistent rotational velocity.
Accelerating a transfer unit to a velocity which enables the transfer of the bags without the filling device having to be decelerated at the same time for the purpose of the transfer of the empty bags to the rotatable filling device is known from WO 2013/013731 A1. The transfer unit has for this purpose a gripping arm having a gripping unit as a holding unit, wherein the gripping arm is designed as revolving around the transfer unit, on the one hand, to move the gripping arm back into the starting position after transfer of a bag to the filling device, and the gripping arm executes a longitudinal movement, on the other hand, which is adapted at least temporarily to the circumferential velocity of the revolving movement of the filling nozzles, to transfer a bag to the continuously rotating filling device.
However, this device has the disadvantage that the guide of the gripping arm is complex and susceptible to wear due to the combination of revolving movement and longitudinal movement. Because of the tangential movement of the transfer unit—in relation to the rotational movement of the filling device—it also requires an increased amount of space at the production location.
Embodiments of the present invention provide a simpler holding unit, by which the filling device can be operated continuously at constant velocity and additionally manages with less space required.
The starting point is a device for transporting and filling bags, preferably open bags, comprising a filling device, which is rotatable about an axis of rotation, having multiple filling openings distributed over the circumference of the filling device, and also comprising a feeder, using which an empty bag can be fed to a filling opening, wherein the feeder comprises at least one holding unit for a bag which is movable normally to the axis of rotation of the filling device. The term “normally to the axis of rotation” in this case can comprise in principle both a movement component radially to the axis of rotation and also a movement component in the circumferential direction.
Embodiments of the invention provide that the holding unit has two separate holders, wherein the holders are each movable forward and backward along the same open trajectory, wherein the first holder is mounted so it is movable on the filling device, while the second holder is mounted so it is movable on a spatially-fixed guide.
Due to the separation of the holding unit into two holders separate from one another, of which only the second has to be guided separately from (for example, outside) the filling device, less space is required for this second holder than for a holding unit which comprises both holders. At least two holders are necessary so that they can grasp an empty folded bag from two sides and open it.
Due to the separation of first and second holder, they are movable independently of one another and trajectories can be established more easily which do not collide with other parts of the filling device, for example, filling nozzles.
The first holder moves forward on a predefined trajectory to move the empty bag at the same velocity as the filling device with the filling device, until the bag is fastened on the filling device. The first holder then detaches from the bag and moves back on the same trajectory to accept the next empty bag. The second holder executes the same movement sequence, generally simultaneously with the first holder, thus moves forward on a predefined trajectory to move the empty bag at the same velocity as the filling device with the filling device, until the bag is fastened on the filling device. The second holder then detaches from the bag and moves back on the same trajectory, to accept the next empty bag. Since the guide of the first holder is provided on the filling device, no space radially outside the filling device is occupied by this guide in any case.
The trajectory which the respective holder follows is open, and can thus be, for example, a linear or curved route. This differs from closed trajectories from the prior art, where the holder or gripper does not change its movement direction, but rather circulates along a circular path or another closed curve, always in the same direction. Because forward and reverse movement of the respective container takes place along the same trajectory section according to the invention, space is saved in contrast to closed trajectories, because one trajectory section is required there for carrying along the empty bag and another trajectory section is required for returning the holder or gripper into the starting location, wherein the trajectory section for the return of the holder generally lies radially outside the trajectory section for carrying along the empty bag.
In one embodiment variant, first and second holder can be movable in parallel to one another. The trajectories thereof thus extend in parallel to one another, the holders and/or the guides thereof then always have the same spacing along the trajectories. However, it would also be conceivable that the trajectories (in the sense of the path predefined by the guides of the holders) of first and second holder move away from one another, for example, to assist the opening of the empty bag.
In one preferred embodiment, the first holder is mounted so it is movable inside the filling openings and the second holder is mounted so it is movable outside the filling openings. The empty bag can thus be opened most easily so that the bag opening is located below the filling opening. Due to the guide of the first holder inside the filling openings, a corresponding space saving results outside the filling openings, so that a possible housing of the device according to the invention can be constructed smaller.
The second holder is preferably located at least partially radially inside the largest diameter of the filling device. In this case, the second holder is always located in all of its possible positions at least partially radially inside the largest diameter of the filling device, and never completely outside. Space can thus be saved at the height of the second holder in the radial direction—in relation to the axis of rotation of the filling device—outside the filling device. The spatially-fixed guide of the second holder can be located radially outside the largest diameter of the filling device in this case. This space savings in the radial direction may be increased still further if the spatially-fixed guide of the second holder is also arranged radially inside the largest diameter of the filling device, and therefore the second holder is also completely arranged radially inside the largest diameter of the filling device.
A particularly simple trajectory, which is compatible with the rotational movement of the filling openings, results if the trajectory of the first and/or the second holder is one section of a circular path, i.e., a circular arc. The curvature of the section of the circular path is oriented outward in this case. In particular, it can be provided that the center point of the circular path lies on the axis of rotation of the filling device. The circular path of the trajectory of the first and/or the second holder is then concentric to the axis of rotation of the filling device.
The first and/or the second holder can each comprise a suctioning device, preferably because it only engages outside the empty bag. Therefore, first and second holder can engage from the outside on the empty bag, suction it, and open it. Engaging into the interior of the bag is not necessary.
It can be provided that the suctioning device of the first and/or the second holder is movable radially in relation to the rotational axis with respect to the remaining holder. The opening of the bag can then be caused by the radial movement of one or both suctioning devices. The suctioning device can be embodied, for example, by one or more suction nozzles.
It can also be provided that the first and/or the second holder each comprises a bag lifter (or lifting device) for lifting a bag from a transfer position into a filling position. When an empty bag is fed to the two cooperating holders, the transfer position, where the bag is transferred to the holders, can be at a distance below the filling opening, for example, below the filling nozzle. To enable filling without loss, the empty bag has to be raised upward by the holders to the filling opening, at best beyond the filling opening. These bag lifters can be pivot arms, for example, which can then lift the actual holder, i.e., for example, the suctioning device, and lower them again. The bag lifter can be embodied as a parallelogram guide.
In the embodiment of the bag lifter as a parallelogram guide, a movement having radial component also results for the suctioning device (or another holder for holding the empty bag).
The feeder, using which an empty bag can be fed to a filling opening, can also comprise a pivot unit, using which an empty bag is pivotable from a storage position, in particular a horizontal position, into a transfer position, in particular a vertical position, for transfer to the holding unit. The pivot unit is not directly connected to the rotating filling device, but rather is arranged spatially-fixed radially outside and/or adjacent to the filling device. The pivot unit feeds the empty bags to the holding unit, this holding unit accepts them from the pivot unit. The pivot unit can therefore comprise two pivot arms, which grasp the folded empty bag at the edges and lift it from the horizontal position on a stack, which is located adjacent to the filling device, inward toward the filling device and simultaneously upward in the direction of the holding unit into a transfer position. The pivot axis is preferably arranged horizontally in this case, in particular tangentially to an imaginary circle about the axis of rotation of the filling device.
For simple fixing of the bags on the filling openings, it can be provided that the filling device has fixing units in the region of the filling openings, which are designed to hold a bag at the filling opening in the filling position after detachment of the holding unit. These fixing units can be, for example, clamps adapted to the shape of the filling opening, in particular the shape of a filling nozzle, which press the bag from the outside against the filling opening, in particular the filling nozzle. For example, one or two pairs of fixing units can be used. One pair can be used for the bag transfer and only clamps the bag centrally on the filling device, one pair has a shape adapted to the filling nozzle and encloses the filling nozzle.
To remove a filled bag from a filling opening, a bag removal unit (bag remover) which can be arranged spatially-fixed (i.e., not co-rotating on the filling device) can be provided, the gripper of which are movable, in particular pivotable, normally to the axis of rotation of the filling device, wherein the grippers are movable forward and backward along the same trajectory in the circumferential direction (in relation to the axis of rotation of the filling device). In principle, the movement normally to the axis of rotation comprises both a movement component radially to the axis of rotation and also a movement component in the circumferential direction, i.e., a movement along and/or tangentially to an imaginary circle about the axis of rotation. Due to the movement of the grippers forward in the circumferential direction, the grippers can follow the rotation of the filling device, while they grasp the bag and then pull it off and, for example, deposit it on a further conveyor unit. To be able to grasp the next bag, the grippers have to be moved backward in the circumferential direction. Subsequently, they again follow the rotation of the conveyor device, and so on.
The movement of the grippers in the circumferential direction can be predefined by a guide, such as a slotted guide, the trajectory can then be a linear or curved route, in particular a circular arc, preferably a circular arc concentric to the axis of rotation of the filling device. Or the grippers can be suspended between two pivot arms having pivot axes parallel to the axis of rotation of the filling device, to achieve a movement in the circumferential direction.
The grippers of the bag removal unit can additionally be movable or pivotable from top to bottom, to pull off a filled bag downward from the filling opening.
To compact the bulk material in the bags, a vibration plate can be provided below each filling opening, which is inclined outward viewed from the filling opening, so that filled bags rest on the vibration plate. Such a vibration plate can be used not only for the device according to the invention, but rather for any device for transporting and filling bags, preferably open bags, comprising a filling device rotatable about an axis of rotation having multiple filling openings distributed around the circumference of the filling device.
In particular, a flap pivotable toward the filling opening can be provided in an end section of the vibration plate, which is remote from the filling opening, to support a filled bag in the bottom region. This flap is used to relieve the bag material and thus causes bulging of the bag, whereby better filling and therefore lowering of the degree of filling are in turn provided. One or more impacts of the flap on the bottom of the bag as it folds up can also contribute to compacting the bulk material in the bag.
The method for transporting and filling bags, preferably open bags, using a device according to the invention presumes that the filling device having multiple filling openings distributed around the circumference of the filling device rotates at constant velocity, wherein a feeder feeds an empty bag to a filling opening, wherein the feeder comprises at least one holding unit for a bag, which is movable normally to the axis of rotation of the filling device. It is provided in this case that two separate holders of the holding device jointly accept an empty bag at a transfer position, the holders are each moved synchronously forward along the open trajectory, while the bag is fastened to the filling device, the holders release the bag and subsequently the holders are each moved backward, in particular synchronously, along the same open trajectory into the transfer position, to again accept an empty bag.
Synchronous movement is understood here to mean that first and second holder move at the same angular velocity and are radially aligned with one another. The forward movement should best occur synchronously, because otherwise the bag, more precisely its opening, does not have a defined position. Thus, a non-synchronous forward movement (and therefore a relative movement of, for example, the suctioning device in the circumferential direction) would also be conceivable, preferably during the short time of the bag opening, to facilitate the bag opening, for example, if the bags are electrostatically charged. The reverse movement of the holders will also generally be synchronous, since the holders have to be back in the transfer position at the same time.
The invention will be explained in greater detail on the basis of an exemplary embodiment. The drawings are by way of example and are to illustrate the concept of the invention, but are in no way to restrict it or even exhaustively reproduce it.
In the figures:
The filling device 2 has a rotating column 9, which is arranged vertically in the operating state, and which is rotatable about an axis of rotation 10. The filling device 2 rotates counterclockwise at constant velocity here. Of course, the filling device 2 can also be moved clockwise with accordingly mirrored arrangement of the device according to the invention. The bags 1 can be fixed by clamping on the filling nozzle 3 using clamps 11, which are mounted so they are movable on the filling device 2 and are adapted to the shape of the filling nozzle 3. The carrier 16, which is in the form of a circular disk here, of the filling device 2 carries the filling funnels 4 located above the carrier 16, on the one hand, and the filling nozzles 3 arranged below the carrier 16. The diameter of the carrier 16 therefore forms the largest diameter of the filling device 2 in this example.
The first holder 12, which is mounted so it is movable on the filling device 2, of the holding unit 5 is largely concealed by the filling nozzle 3 in
The second holder 13 is located, viewed in the rotational direction of the filling device 2, at this time at the very beginning of the guide 14 and can already be aligned now in the radial direction with a filling opening 15. At the time of the pivot movement of the pivot unit 6, the holders 12, 13 do not necessarily have to be located at the beginning of the guide 14. The pivot unit 6 can, with vertical position of the bag 1 (see
The construction of first holder 12 and second holder 13 is recognizable in
The holders 12, 13 and/or the suction nozzles 19 thereof are located in the transfer position in
The trajectories of the holders 12, 13 are formed as circular arcs concentric to the axis of rotation 10 and therefore extend in parallel to one another. The trajectory of the first holder 12, more precisely the trajectory of the mounting of the pivot arms 17, extends inside the filling openings 15, the trajectory of the second holder 13, more precisely the trajectory defined by the guide 14, extends outside the filling openings 15. The guide 14 of the second holder 13 is arranged radially outside the carrier 16, the second holder 13 is always located partially radially inside and partially radially outside the carrier 16 and/or the largest diameter of the filling device 2.
The holders 12, 13, as will be described hereafter, are moved cyclically about the axis of rotation 10, namely always rotated one portion about the axis of rotation 10 in one direction and subsequently one portion in the other direction and then again one portion in the first direction, and so on, while the filling device 2 rotates continuously at constant velocity about the axis of rotation 10, i.e., changes neither the rotational direction nor the rotational velocity.
During these procedures—opening and placement of the bag 1—the second holder 13 moves along the guide 14 synchronously with the filling device 2, i.e., it has the same angular velocity in relation to the axis of rotation 10 of the rotating column 9 as the filling device 2. The first holder 12 is also moved synchronously with the filling device 2, i.e., it has the same angular velocity in relation to the axis of rotation 10 of the rotating column 9. Instead of the arm 26, which is rotatable about the axis of rotation 10 (see
The first holder 12 is moved back again, after the fastening of the bag 1 by the clamps 1 on the filling nozzle 3, by a rotational movement of the arm 26 into the transfer position according to
In
Number | Date | Country | Kind |
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17154247.5 | Feb 2017 | EP | regional |