The invention relates to a system and a method for production and subsequent palletizing of tube segments, bags or sacks according to the preambles of the patent claims 1 and 20.
These types of systems are known since a long time. Tube segments, bags or sacks are produced in general from single or multi-layered sheets of material in processing machines meant for it. To form the tube segments, devices of the type shown and described, for instance, in the patent document DE 36 40 219 C1 and in DE 44 40 660 C2, are used. Sacks, such as in the form of cross bottom valve sacks, can be fabricated from this type of tube segments. In the patent document DE 195 49 618 C2, it is shown how the ends of a piece of a tube are drawn up in the production this type of cross bottoms. However, various other types of sacks and bags are also known, which are produced with different types of devices. Thus, such devices are also known, with which the carry bags with handles are produced from paper sheets.
Even when the named documents are concerned mostly with paper sheets or tubes, the present invention is not limited to this material. Tube segments, bags or sacks made from plastic or from a combination of plastic and paper are also possible. Similarly, as mentioned at the beginning, the material can also consist of one or more layers.
The said tube segments, bags or sacks are normally stacked for the purpose of their transportation or storage. For stacking the products the known systems include a stacking device, as shown, for instance, in the patent document DE 37 07 845 C2. As a rule, these stacks are subsequently deposited on palettes in order to be able to transport them easily. However, the stacks can also be temporarily stored on or in temporary storages before they are arranged or deposited on storage elements. After stacking, and after their possible temporary storage, the stacks are arranged and deposited in storage elements.
The stacks made from tube segments, bags or sacks can be arranged and stacked in large numbers in a storage element, if the edges of the tube segments lie exactly one on top of the other in the individual stacks, which lye on one another. In the known systems, for production and palletizing, there is room for improvement potential in this regard. Moreover, the stacks are in general deposited manually in the storage elements. This procedure is slow and is ridden with immense inaccuracies, very personnel-intensive and hence expensive. On the whole, the procedures according to the present state of the technology for arranging and storing of the stacks are very ineffective.
Therefore the task posed by the present invention is to propose a system for production and subsequent palletizing of tube segments, bags or sacks, which avoids the aforesaid disadvantages.
This task is solved according to the invention by the features of the characterizing part of the claim 1. According to that, the named system has an alignment unit for the stacks of the tube segments or sacks, which reduces the mutual deviation of the edges of the tube segments, bags or sacks. Therefore, the form of the stack in this alignment unit is better approximated to the parallelepiped form. Compared to the alignment by hand, it can be done much more exactly and also faster.
Since by using this type of equipment, the stack has—at least nearly—a parallelepiped shape, a stack generated by means of it can be picked up in a more advantageous manner by means of a palletizing device, which deposits the stacks in at least one storage element. In case of a stack with a shape that deviates to a great extent from parallelepiped shape, use of this type of palletizing device would not be possible, or the tube segments, bags or sacks may even get damaged in the stack. By using a palletizing device, many more stacks can be deposited on a storage element due to the more precise deposition of the stack, than when they are deposited manually. Stacks can slip or fall down if the stacks are arranged in the storage elements too inaccurately. Thus, by including a palletizing device in a system according to the invention, the transport and storage costs can be saved.
In an advantageous embodiment of the invention, the alignment unit has an alignment table, which is equipped with stoppers. The stack can be arranged on this alignment table independent of the entire system. Thus, the alignment table can, for instance, moved separately. In this type of alignment table, two stoppers are provided. If the principal axis of the tube pieces, bags or sacks to be arranged is transversal to the direction of transport, it is of advantage if one stopper extends parallel to the principal axis of the tube pieces, bags or sacks, while the second stopper is parallel to the direction of the transport. Both stoppers therefore form a right angle. However, in general, the stoppers can be arranged along any two arbitrary lines, whereby both stoppers can form any angle.
It is also advantageous, if the alignment table is equipped with a means for inclining the stacks. This means for inclining can be, for example, conveyor belts, which transform the stack in a horizontal plane to an oblique plane. The oblique plane is then also a component of the alignment table, whereby this oblique plane can then be used for the alignment of the stacks. In which case, also the forces based on the gravitational force act on the tube sections, bags and sacks, which can lead to mutual displacement of the tube segments, bags and sacks.
However, it is especially advantageous, if the device for inclining the stack includes a swiveling device, with which the alignment table can be swiveled to such an extent that the stack is inclined against the gravitational force. After the swiveling movement the stack is inclined, so that the gravitational forces act on the tube sections, bags or sacks so that their edges lie against the stoppers.
The edges of each individual tube segment, bag or sack can come to rest against the stoppers. This leads to an almost optimum parallelepiped form of the stacks.
In an advantageous embodiment of the invention, the swivel axis, about which the swiveling device swivels the swiveling table, forms an angle with both stoppers. In a swiveling movement, each edge of the individual tube pieces, bags or sacks lie against each stopper, so that after this maneuver the tube pieces, sags or sack assume a well-defined spatial position. This alignment is particularly effective, if the swivel axis and each stopper enclose an angle of approx. 45 degrees. Depending on the format of the tube pieces, bags or sacks, a different angle can also be advantageous. If, for example, the length of a tube piece, bag or sack is twice its width, an angle of 30 degrees (between the longitudinal edge of the bag and the swivel axis) can be advantageous. In general, if one takes the longer edge of the tube piece, bag or sack, into consideration, then the swivel axis makes an angle between 0 and 45 degrees with this edge or with the stopper associated with that edge.
The stacks must be supplied to the alignment unit. Therefore, in a system according to the invention, a first transport device is provided, which includes transporting elements such as transport rollers or conveyor belts, which carries the stacks to and fro from the alignment table and a transport device. It is of advantage, if this transport device includes a transition element, which connects the transport device with the alignment table and which can be made to swivel or travel. A transport device with this type of design should be provided, especially if the swivel axis forms an angle with the stoppers and the swivel axis does not pass through the top of the alignment table, because in that case the range of swivel of the alignment table will sweep through the built design area of the transport device.
In a further development of the invention, the system is equipped with a second transport device for transporting the stacks onto the alignment table, which has a drive mechanism mounted with firm attachment with the frame and which is at rest during the swiveling movement of the table. This drive, which can be stationary, fixed on the machine frame, transmits the driving force to the transmission gear of the device, which, if the alignment or the swiveling table is not swiveled, is in active connection with the other driving force transmission devices. The first transmission device can be a disk, which is pressed with elastic force in the direction of the alignment table, so as to ensure optimum transmission of force. The other force transmission devices can be one or more shafts, on which the conveyor belts or conveyor straps are mounted.
It is of advantage to equip the arrangement table with a vibration-generating element. By generating vibrations with sufficient amplitude and appropriate frequency, the individual tube pieces, bags or sacks can move away from each other for a short period, so that the force of friction between them is reduced. Independent movement of the individual hose pieces, bags or sacks is thus facilitated. If the alignment table is swiveled, then the edges of each individual tube section, each individual bag or each individual sack can lie against the stoppers. Consequently, stack with almost perfect parallelepiped shape is generated easily.
In order to transform the shape of the stack into a parallelepiped shape, it can also be sufficient to provide a device for inclining the stack, which inclines the alignment table, already while it is in idle position, or keeps it in an inclined position, so that the stack is inclined at the time it is placed on the alignment table. The shape of the stack can be transformed into this form of embodiment according to the invention, for instance, on a slanting alignment table, so that the alignment takes place due to the influence of the gravitational force. After completing of this alignment process, the alignment table can be brought into a suitable position by means of the device for inclining, so that the stack can be transported away.
In another advantageous embodiment according to the invention, the alignment table comprises a vibration transmission element, which supports the stack at least from time to time and which can be impinged with vibrations by the vibration-generating element. Preferably, before impinging with the vibrations, the stack is lifted off from the conveyor element(s) with this vibration-transmitting element. The lowest tube piece, the lowest bag or the lowest sack is therefore not exposed to the static friction force, which acts between the conveyor element and this tube piece, bag or sack.
Thereby, it is advantageous if the vibration transmission element includes a carriage table that is built like a comb. In that embodiment, the carriage table can stand between the conveyor elements, such as for instance conveyor belts. For the purpose of aligning the stacks, the carriage table can be lifted up in such a way that the individual prongs of the comb of the carriage table rise forth between the conveyor belts and carry the stack alone. The number of prongs of the comb, and thus of the conveyor belts, must be dimensioned in such a fashion that the tube pieces, bags or sacks sag through as little as possible between the prongs of the comb.
It is also advantageous, if the vibration transmission element includes areas for deposition, on which the stacks can lie, which areas have lesser friction with the stack material than with the second transport device. The static friction between the areas for the deposition is thereby determined by the size of the areas of the deposition as well as also their coefficients of friction. The areas of deposition can therefore be lateral edges of the carriage elements built with a flat form. In order to achieve least possible coefficients of friction, these carriage elements can consist of metal. Further, the carriage elements can be provided with a suitable coating that offers, besides the low friction, also the advantage of greater protection against wear.
In a further advantageous embodiment of the invention, the alignment table is equipped with a device for clamping, with which the stack or the stacks can be held firmly on the alignment table. The parallelepiped-shaped stack, which was created shortly on the inclined or swiveling alignment table, should not lose its alignment again before the further transport. Due to that reason, one can fix the stack on the means of transport with the clamping device, till the individual sacks have assumed the horizontal position again. Only thereafter the pressing of the stack against the means of transport is ended again. In addition to that, the clamping device is brought in the vicinity of the stack or the stacks, so that the uppermost layers of the stack do not fall down or sag through during the vibration of the alignment table.
In an especially advantageous embodiment, the system according to the invention comprises at least two alignment tables. In that manner, the throughput of the alignment unit can be adjusted to the capacity of the other components of the system, in particular the production capacity of the function unit for production of the tube segments, bags or sacks.
Advantageous thereby is, if at least two alignment tables follow each other in the transport direction of the stack. With that the stack of the sacks can be transported sequentially, so that the transport devices within the system according to the invention can remain simple.
In an advantageous embodiment, the first alignment table, out of at least two alignment tables in the direction of transport of the stack, includes a second transport device, with which the stack can be transported from the first alignment table onto the second alignment table. Directly after a stack has been transported away through the first alignment table onto the second alignment table, the first alignment table can be impinged with another stack. In this manner each of the two alignment tables can align one or more stacks. In the same manner, the second alignment table, of the at least two alignment tables, can also have a transport device with which the stacks can be transported away from the first alignment table through the second alignment table.
For simultaneous alignment of the stacks on several alignment tables, it is advantageous, to swivel these swivel tables with the help of a swiveling device, whereby the swiveling movements of the alignment tables stand in mutual dependence by means of a coupling element. A single driving mechanism can thereby take care of the swiveling movement of all swivel tables, whereby the drive mechanism can act on a steering rod. The steering rod acts on its part on the swivel tables, so that they carry out same turning movement at the same time. With this, it is ensured that the swivel tables, which carry out the picking up movements, do not come into mutual contact during the swings.
In a further advantageous embodiment of the system according to the invention, a coupling between at least a part of the stoppers is provided, with which the stoppers can move from stop position relative to the alignment tables into a released position, in such a fashion that the stack can be transported past the stopper position, if the stoppers are in the released position. For that, the stopper, which is arranged transversally to the direction of the transport, consists of several individual elements, for instance, rods or pipes, which are supported rotatably at one end on a carriage element. Through a coupling element, the individual elements can be rotated together in direction transversal to the direction of the transport, so that they can be brought from the stopper position into the release position and vice versa. This type of movement is especially fast. Further, in the release position, the movable elements are arranged in an especially place saving manner, so that the design space can be saved on the whole. In addition to that, the stopper can be swung by a small angle into the direction of the transport, so that the stopper does not stand any more in contact with the stack. With that it is avoided, that the order of the stack brought into the parallelepiped form is not destroyed again.
Further examples of embodiments of the invention follow from the description of the objects and the claims. The individual figures show:
The
The stack 11, transported in the direction of the transport z, is conveyed so long by the conveyance belts 16, till it touches the stopper 21. This contact is detected by an appropriate, not further described, sensors. At that moment, the driving mechanism 19 is brought to halt. After that, the carriage table 22, which is built in the
The swiveling mechanism 24 now moves the turning lever 25 in the direction of the arrow C. With the turning lever 25, a rod 26 is connected flexibly, which on its part is connected flexibly with the base frame 15. The movement of the turning lever 25 leads therefore to a swiveling movement of the base frame 15 of the alignment table 4a, 4b about the swivel axis 27. In that position, the alignment table 4a, 4b continues and the vibration mechanism 30, which can be an electromotor equipped with flyweight, sets the carriage tables 22 into vibrations. The stoppers 21 and 31 also can be set in vibrations through the vibration mechanism 30. In this manner, the individual tube pieces, bags or sacks of the stack 11 are lifted away from each other for a short period in such a manner that the frictional force is reduced between them. The individual tube pieces, bags or sacks can thus slide, independent of one another under the influence of the gravitational force, against the stopper 21 and also against the side lay 31 shown in
After completion of the alignment of the stack 11, the deflection sheaves 41, 43 are brought back again into their original position for the purpose of the transport of the aligned stack 11 or for feeding a stack 11 to be aligned.
For the alignment of stacks of other flat objects—such as paper sheets—the features of the preceding description and/or of the claims can be used with advantage.