Method and device for rotating a folding-box blank

Abstract

The invention relates to a method and device for reliably and gently rotate a folding-box blank that has application portions.

Description

[0001] Title: Method and device for rotating a

[0002] Folding box blank

[0003] Description

[0004] The invention relates to a method and a device for rotating a folding box blank or the like.

[0005] Folding box blanks are processed in a process chain with several consecutive processing stations. Examples of the processing steps performed at the processing stations include folding and gluing.

[0006] As a folding carton blank passes through such a process chain, it sometimes needs to be rotated. This is the case, for example, when functional components (e.g., tear strips or adhesive traces) are applied in a preceding or following process step, but the folding process (depending on the design of the folding carton) requires the folding carton blank to be rotated by, for example, 90°.

[0007] "Rotating" here and below means that the folding box blank is rotated around an axis orthogonal to its plane by more than 30°, for example by 45°, usually by approximately 90°, but conceivably also by 180°. Rotating the folding box blank significantly rotates an edge that was the leading edge of the folding box blank before rotation (as seen in the process direction) out of the transport direction. Thus, the rotation can cause another edge of the folding box blank to become the "new" leading edge. For example, rotating the folding box blank by 90° turns an edge of the folding box blank that was a side edge before rotation into the "new" leading edge.

[0008] Aligning the folding carton blank is different from rotating the folding carton blank. During alignment, a crookedly fed folding carton blank is aligned in such a way that a crooked edge of the folding carton blank is straightened, typically orthogonally aligned to the process direction. The leading edge remains the

[0009] Leading edge. "Alignment" therefore only concerns the correction of angular errors in folding box blanks. Deviations / angular errors of a few degrees (less than 10°) are corrected.

[0010] The distinction between "aligning" and "rotating" a folding carton blank is common. For example, WO 2017 / 021886 A1 discloses a process chain with an alignment unit. It is arranged upstream of a first process station. A turning station or module is arranged between the first process station and a second process station.

[0011] In the turning station of WO 2017 / 021866 A1, the folding box blank to be turned is gripped at one of its top corners by a turning device and rotated by a predetermined angle. This turning station is relatively large, complex to manufacture, and slow to operate. A turning module with roller conveyors is described, for example, in EP 1 666 386 B1. In this module, the folding box blank rests with its entire surface on two roller conveyors arranged side by side, which can operate at different conveying speeds. Furthermore, a method and a device for aligning, but not for rotating, a carton are known from DE 10 2017 114 334 A1. A device and a method for correcting the position of carton blanks are known from DE 198 21 875 A1.

[0012] The invention is based on the object of providing a method and a device that enable the simple and efficient rotation of folding box blanks or cartons by more than 30°. Furthermore, the space required for the rotation module should be significantly reduced compared to conventional rotation modules. Furthermore, the method should be easy to parameterize and implement with short cycle times. Finally, a lower energy requirement than previously required for the operation of the rotation module would also be desirable.

[0013] This object is achieved according to the invention by a method having the features of claim 1 and a device having the features of the independent claim.

[0014] One advantage of the invention is that the movement of the folding box blank can be controlled very precisely. The folding box blank can therefore be positioned relatively precisely for subsequent process steps by the rotation module, i.e. rotated precisely. Viewed in the direction of the process chain (process direction), the rotation module can be comparatively short because the rotational movement is accomplished by just two transport devices that act "point-like" on the folding box blank. Since the transport devices themselves are typically stationary and the folding box blank is moved past the transport devices, the transport devices do not have to be repositioned after a folding box blank has been transported, which means comparatively high cycle times can be achieved. Specifically, this is achieved by a method for rotating a folding box blank using a rotation module.A "folding box blank" can be an element made of cardboard, a cardboard-like material or corrugated plastic (for example polypropylene) or other suitable materials from which a three-dimensional folding box can later be made. The folding box blank can be completely flat, but it can also be partially pre-folded. The term "rotating" is also to be understood in contrast to "aligning", as explained above in the description of the prior art. In the context of the present invention, this is understood to mean rotational movements with a rotation angle of at least + / -30°, preferably in the range of approximately + / -45° or approximately + / -90°.

[0015] According to the method according to the invention, at least one pair of transport devices with a first transport device and a second transport device is provided in such a way that the first transport device and the second transport device are laterally spaced apart from one another. If one starts from a process direction, then the two transport devices are typically arranged at least approximately "at the same height" and next to one another in this process direction. At least temporarily, the folding box blank is transported by both the first and the second transport device. The first transport device is provided in such a way that it acts on a first point-like location on the folding box blank. It is to be understood that the term "approximately point-like" in the context of the present invention, i.e. here and below, is in no way to be understood in a mathematical sense.Rather, the use of the term "approximately point-like" is intended to express the technical reality in that a contact point between the transport device and the folding box blank is very small in comparison to the dimensions of the folding box blank, and this in both Cartesian directions of a plane of the folding box blank. If, for example, the transport devices are each implemented by a pair of wheels, then in the present invention the lateral extent of the contact point, i.e. the extent parallel to a rotational axis of the wheels, is comparatively small, in any case considerably smaller than the corresponding lateral extent of the folding box blank.Even viewed in the circumferential direction of the wheels, in technical reality the contact point does not have a line shape in the mathematical sense with a line thickness of “zero”, for example due to elastic deformation in the area of ​​the contact point on the folding box blank and / or on the wheels. Typically the Cartesian dimensions of the contact point are in any case at least one order of magnitude, i.e. a factor of 10, smaller than the corresponding Cartesian dimensions (maximum width and maximum length) of the folding box blank. In this way the first transport device can exert a first movement vector on the folding box blank at the first approximately point-shaped contact point or generate one on the folding box blank, which is characterized by a first direction and a first amount.Or, in other words: the folding box blank is moved by the first transport device at the first contact point according to the amount and direction of the first movement vector. If the first transport device is stationary in the process direction, the first approximately point-shaped contact point is also stationary in the process direction, but the first approximately point-shaped contact point moves along the moving folding box blank. The contact point is therefore stationary from the perspective of an observer at rest relative to the transport device, but moving from the perspective of an observer at rest relative to the folding box blank.

[0016] Analogous to the first transport device, the second transport device is provided in such a way that it acts on a second, approximately point-shaped contact point of the folding box blank, whereby the above definition of the term “approximately point-shaped” applies here again. The second transport device can exert a second movement vector on the folding box blank at the second, approximately point-shaped contact point, which movement vector is characterized by a second direction and a second amount. Or, in other words: the folding box blank is moved by the second transport device at the second contact point in accordance with the amount and direction of the second movement vector.If the second transport device is stationary in the process direction, the second approximately point-shaped contact point is also stationary in the process direction, but the second approximately point-shaped contact point moves along the moving folding box blank. The contact point is therefore stationary from the perspective of an observer at rest relative to the transport device, but moving from the perspective of an observer at rest relative to the folding box blank.

[0017] Since the two transport devices are arranged laterally adjacent to one another at a distance from one another, the two motion vectors are laterally spaced apart. They are at least substantially parallel to one another. The first direction of the first motion vector and the second direction of the second motion vector are thus at least substantially parallel to one another.

[0018] The distance is typically selected to ensure that folding box blanks of standard dimensions can be moved simultaneously by both transport devices. If necessary, the distance can be varied. For a comparatively small folding box blank, the distance can be selected to be comparatively small, and for a larger folding box blank, it can be selected to be comparatively large.

[0019] According to the invention, the magnitudes and / or signs of the motion vectors are controlled such that the folding box blank moves along two predetermined and at least partially curved motion lines. The motion lines are virtual lines that virtually represent the two contact points on the folding box blank as the folding box blank moves past the transport devices relative to them.

[0020] If, for example, the amounts and signs are the same, the folding box blank is moved in a straight line. If, for example, the amount of the right-hand movement vector seen in the process direction is greater than that of the left-hand movement vector, the movement line is curved to the left in the process direction. If, for example, the amount of the left-hand movement vector seen in the process direction is greater than that of the right-hand movement vector, the movement line is curved to the right in the process direction. If, for example, the amounts of the movement vectors are the same but the signs are different, the folding box blank is rotated about a stationary axis which is located in the middle between the two transport devices.

[0021] It is particularly important to note that the rotation of the folding box blank is not (only) characterized by a detected or determined alignment or orientation of the folding box blank at the beginning of the movement and a desired alignment or orientation of the folding box blank at the end of the movement. According to the invention, the folding box blank moves for the rotation along a predetermined and desired path, namely along the two aforementioned lines of movement.

[0022] The two lines of movement can be specified manually or automatically. For example, it is possible for an operator to simply specify the two end points of the lines of movement, and then the two lines of movement are automatically determined depending on the start points and, if necessary, other boundary conditions. It is also possible for the operator to specify the two start points and the two end points of the lines of movement, and then the two lines of movement are automatically determined depending on these and, if necessary, other boundary conditions. Typically, a line of movement is formed by a polynomial spline. The said boundary conditions can, for example, include that certain areas of a folding box blank are to be left out of the lines of movement. Such areas can be, for example, existing glue points, punched out areas, cutting lines, etc.

[0023] Furthermore, it is understood that the two movement lines are specified indirectly or—preferably—directly. An indirect specification can, for example, consist in initially specifying movement lines from other reference points of the folding box blank, from which the movement lines at the contact points then result from the relative positions of the two contact points to these reference points.

[0024] Accordingly, it is advantageous for the movement lines to be specified directly. Alternatively, it is conceivable for the movement lines to be determined indirectly from boundary conditions that are specified directly. In addition to movement lines from other reference points of the folding box blank, coordinates of the start and / or end points and / or the track width of the curved section of the movement line can also or alternatively serve as boundary conditions.

[0025] Since in the real technical world, the contact points are not ideally point-shaped, a certain amount of slippage occurs as a result of the rotation of the folding box blank relative to the transport devices. This means that the actual movement lines do not necessarily correspond with absolute mathematical precision to the movement lines specified at the contact points. However, this is irrelevant for achieving the advantages of the invention.

[0026] It was described above that the lines of movement through the two contact points are virtually drawn on the folding box blank as it moves. In this way, both the position and the orientation of the folding box blank are clearly defined at any time during the movement. This could possibly be used not only to control the movement of the folding box blank, but also to regulate it, for example by using image recognition to provide feedback on the current position and orientation of the folding box blank during the movement process in the rotary module. For example, an image capture device could identify a characteristic point on the folding box blank. Such a characteristic point could be a corner point of a folding box blank, for example.On the basis of the two movement lines, a desired movement line of this characteristic point could then be defined, and subsequently the two transport devices could be controlled in such a way that the characteristic point follows the defined movement line.

[0027] When carrying out the method according to the invention, the virtual movement lines serve as "guide curves" for controlling the first and second transport devices, so that the folding box blank carries out the desired rotational and longitudinal movements, i.e. moves at least approximately along the predetermined and at least partially curved movement lines. The shape of the movement lines depends on the desired angle of rotation and, if applicable, the aforementioned boundary conditions and can, for example, be predetermined as a function of the dimensions of the folding box blank, in particular as a length of the folding box blank viewed upstream of the rotation module in the process direction. In addition, the shape of the movement line can also be predetermined as a function of a position of the folding box blank upstream of the rotation module relative to a reference line running parallel to the process direction.Finally, the shape of the movement line can also depend on a desired compensation of an inclined position of the folding box blank running into the turning module.

[0028] A control device, for example a computer, can be used to determine the desired line of movement. This computer can receive information from one or more sensors to determine the desired line of movement. These sensors can be used to record, for example, the dimensions, in particular a length, and / or a lateral offset and / or an inclination of the folding box blank moving towards the rotary module. The dimensions of the folding box blank can also be contained in a database or at least partially entered by an operator. The control device then controls the transport devices so that the folding box blank moves along the desired lines of movement.

[0029] It is advantageous that, before specifying or determining the movement lines, application areas arranged on the folding box blank are identified. Accordingly, movement lines adapted to the identified application areas and / or a control of the amounts and / or signs adapted thereto can be provided.

[0030] For the purposes of the invention, areas with functional components, such as tear threads, openings, adhesive traces or sensitive pressure marks, are to be understood as "application areas".

[0031] Application areas are therefore areas that, for technical reasons, should not be crossed by the rollers of the transport device, or areas that can be crossed, but where rotation with the roller over the corresponding application area should be avoided. For example, silicone tapes can be crossed "straight," but it is unfavorable to rotate an application area with an applied silicone tape under the roller, as this could lead to displacement of the silicone tape.

[0032] It is also advantageous if the specification of the movement lines and / or the specification of the boundary conditions for determining the movement lines takes place depending on the identified application areas. Accordingly, the application areas can be omitted when contacting by means of the transport devices. Alternatively, it is conceivable that the amounts and / or signs are designed in such a way that the application areas are passed over particularly gently. The method according to the invention makes it possible to rotate folding box blanks through angles of approximately ± 90 ° or even more using a rotary module that is very short in the transport direction. Because the rotary module required to carry out the method is very short, the space required is small. This is a considerable advantage, especially in long process chains with many work stations.

[0033] In addition, the rotary module required to carry out the method is very simple and cost-effective. For example, the first transport device can have a first rotary drive and the second transport device can have a second rotary drive. The rotary drives can each be implemented, for example, by pairs of wheels with one driven wheel and an opposite non-driven wheel, with the folding box blank being guided between the two wheels of a pair of wheels. For example, one wheel of a pair of wheels can be subjected to a force against the other wheel of the pair of wheels by means of a pre-tensioning device, so that the folding box blank is clamped between the two wheels. Very different devices are possible as a pre-tensioning device, for example a pneumatic cylinder.In this case, the contact pressure could be adjusted via the pneumatic pressure of the pneumatic cylinder, which could prevent pressure marks from occurring if the folding box blank becomes jammed. It is fundamentally conceivable that several pairs of transport devices are provided, one behind the other and at a distance from one another as seen in the process direction, and that each pair only carries out a defined partial rotation of the folding box blank, so that the total rotation of the folding box blank results from the sum of the partial rotations. However, it is preferred that the rotation module only comprises a single pair of transport devices and that the total rotation of the folding box blank is brought about by this single pair of transport devices.

[0034] The rotary drives can be speed-controlled drives or position-controlled drives. However, position-controlled drives are particularly preferred. An example of a position-controlled drive is an electric servomotor, for example a PSM motor with a closed-loop encoder system. The use of an electric drive has the advantage that, apart from electrical energy for the drives of the transport devices, no auxiliary energy, such as compressed air or other sources, is required. The electric drives of the transport devices of the rotary module can be controlled very precisely, enabling very precise control of the rotation of the folding box blank.

[0035] The angle of curvature of the curved area(s) of the movement lines corresponds to the specified angle of rotation of the

[0036] Folding box blank. The curved area(s) have a curvature of at least 30°. Typically, they have a curvature of 90° (+ / - 10°) or 45° (+ / - 10°).

[0037] It is also possible for the movement lines to have several curved areas that are curved in opposite directions. For example, a first curved area can cause a rotation in one direction, while a subsequent, larger curved area can have a significantly larger angle of rotation in the opposite direction. This can compensate for an offset of a folding box blank relative to a subsequent processing station or alignment unit. The total angle of rotation of the folding box blank is determined by adding together the positive and negative angles of rotation of the curved areas.

[0038] The curved areas of the movement lines are created when using rotary drives with the same diameters by operating the rotary drives of the two transport devices at different circumferential speeds at the contact points to the folding box blank.

[0039] When using rotary drives of the same diameter, the straight sections of the movement lines can be created by operating the rotary drives of both transport devices at the same peripheral speeds at the contact points with the folding box blank. If rotary drives of different diameters are used instead, the straight sections of the movement lines must be created by operating the rotary drives of both transport devices at correspondingly different peripheral speeds at the contact points with the folding box blank.

[0040] If, for example, the first transport device drives the folding box blank at a higher speed than the second transport device, then the difference between these speeds leads to the folding box blank performing a rotary movement.

[0041] At a given distance between the transport devices, the rotational speed of the folding box blank is controlled by the difference in the speeds at which the transport devices drive the folding box blank to be rotated (magnitudes of the motion vectors). In other words: a small radius of the line of motion is caused by a large difference in the magnitudes of the motion vectors of the transport devices. A large radius of the line of motion results from a small difference in the magnitudes of the motion vectors of the transport devices.

[0042] It is possible for the lines of movement to comprise a straight-line region before the at least one curved region, after the at least one curved region, or both before and after the at least one curved region. Typically, however, they comprise a curved region with a curvature of more than 30°. It is advantageous if the two lines of movement, in particular at least one straight region or at least one curved region, do not cross one, several or all of the application regions. Alternatively or additionally, it is advantageous if the two lines of movement, in particular at least one straight region or at least one curved region, are both designed at a distance from one, several or all of the application regions. Accordingly, a particularly controlled rotation is possible and the application region(s) are not impaired.If, for example, an application area has a recess or opening that is crossed by a curved area, the lack of contact can lead to uncontrolled rotation of the folding box blank. If, for example, an application area has an adhesive surface that is crossed by a curved area, the acceleration during rotation can impair the adhesive surface. Therefore, a particular advantage is that the movement lines and / or the boundary conditions for the movement lines are determined depending on the identified application areas.

[0043] If a folding box blank is designed in such a way that at least one application area has to be crossed by a curved area of ​​one of the two movement lines, it is particularly advantageous if a curved area of ​​a first of the two movement lines crosses the application area with a larger radius and a curved area of ​​a second of the two movement lines with a smaller radius does not cross the at least one application area and / or is designed at a distance from the at least one application area. Due to the larger radius of the movement line, the forces acting on the folding box blank by the transport device are lower, so that the application area is traveled over more gently.

[0044] A further advantageous embodiment of the method according to the invention provides that the position of the folding box blank is detected, and that at least one transport device is driven as soon as the folding box blank has reached the transport devices of the rotary module. The position of the folding box blank can be detected by means of at least one sensor arranged in the region of the transport devices. Suitable sensors include, for example, optical sensors or ultrasonic sensors. A camera with image recognition can also be used as a sensor. The sensor can, for example, be arranged above the transport devices.

[0045] In a further advantageous embodiment, an inclination of the front edge of the folding box blank is detected before rotation begins. By appropriately adjusting the lines of movement, a detected inclination can be taken into account and consequently compensated for by correspondingly changing the control of the transport devices. An inclination of the front edge can in turn be detected by means of at least one sensor, typically via an optical or ultrasonic sensor in the area of ​​each transport device or in the path of movement of the folding box blank to the transport devices. An inclination of the front edge can also be detected by means of image recognition. The angle of rotation orThe angle of curvature of the curved area of ​​the movement lines is automatically determined, which is necessary to align the leading edge at the end of the rotational movement in the desired manner, for example parallel to an alignment bar.

[0046] For example, if the front edge of a folding box blank is rotated 3° clockwise relative to a target orientation, and the folding box blank is also supposed to rotate 90° clockwise, then it is possible to compensate for this 3° inclination by reducing the specified angle of rotation or curvature of the line of motion from 90° to 87°. The same applies, of course, to a counterclockwise inclination.

[0047] Furthermore, with the aid of the method according to the invention, it is also possible to compensate for a lateral offset of the folding box blank that exists before the folding box blank is rotated. For this purpose, the lateral offset is detected or determined and compensated for by changing the shape of the movement lines. In a simple case, the movement lines for compensating for a lateral offset can have a type of S-shape with a first rotation in one direction and a subsequent second rotation in the opposite direction, with the two rotations being of equal magnitude.

[0048] It has often proven advantageous if the curved area(s) of the movement lines contain circular arcs.

[0049] However, in a further advantageous embodiment, it is also provided that the curved region(s) of the movement lines contain a radius of curvature that changes along the course of the movement lines. For example, the movement lines can contain a clothoid, sinusoid, and / or a cubic parabola. The changing radius of curvature can form a transition region of the movement lines, through which a smooth transition is achieved, for example, between a straight region and a curved region of the movement lines.

[0050] The result is that the torque required for rotation does not increase abruptly, but gently. As a result, the drives are subjected to less strain, drive control is simplified, and the precision with which the rotation occurs is improved. The background to this is that the forces that must be transmitted from the transport device to the folding box blank to be rotated, typically through friction, are reduced, and as a result, slippage of the folding box blank is prevented. This leads to improved precision when carrying out the method according to the invention.

[0051] In a further development of the rotary module according to the invention, it is proposed that each of the transport devices comprises a pair of wheels, but is preferably formed by a (single) pair of wheels, between which the folding box blank can be guided. In contrast to rollers or cylinders, wheels have a comparatively small extension parallel to their axis of rotation, which extension is preferably smaller than their diameter. In this case, it can again be preferred if the wheels each have a surface which is, for example, spherical in cross-section. As a result of this, the lateral extension of the contact point, seen in the process direction, is kept particularly small, so that it comes particularly close to the ideal point shape.

[0052] An embodiment of the method is directed to the following features:

[0053] Method for rotating a folding box blank ( 12 ) by means of a rotating module ( 16 ) , comprising the following steps :

[0054] Providing at least one pair of

[0055] Transport facilities with a first

[0056] Transport device (26R) and a second transport device (26L) such that they are laterally spaced from each other,

[0057] Providing the first transport device (26R) in such a way that it can generate a first movement vector (56R) on the folding box blank (12) at a first approximately point-shaped contact point (54R) of the folding box blank (12), and

[0058] Providing the second transport device (26L) in such a way that it can generate a second movement vector (56L) on the folding box blank (12) at a second approximately point-shaped contact point (54L) of the folding box blank (12), wherein the two movement vectors (56R, 56L) are arranged at least substantially parallel to one another and laterally spaced from one another, characterized in that the method further comprises at least the following step:

[0059] Controlling the amounts and / or signs of the two movement vectors (56R, 56L) such that the folding box blank (12) moves along two predetermined and at least partially curved movement lines (64R, 64L) and / or along two movement lines (64R, 64L) determined from predetermined boundary conditions and at least partially curved, which the two contact points (54R, 54L) virtually draw on the folding box blank (12) during the movement of the folding box blank (12) relative to the transport devices (26R, 26L).

[0060] Further advantages and advantageous configurations of the

[0061] The invention can be seen from the following drawings, their description and the patent claims.

[0062] Show drawing:

[0063] Figure 1 is a perspective view of a device for processing folding box blanks with a roller conveyor, a rotary module and an alignment device;

[0064] Figure 2 is a side view of the device of Figure 1;

[0065] Figure 3 is a plan view of the device of Figure 1;

[0066] Figure 4 is a perspective and more detailed view of the rotary module of Figure 1;

[0067] Figure 5 is a plan view of the device of Figures 1-3 at a first time during operation of the rotary module;

[0068] Figure 6 is a view similar to Figure 5 at a second point in time;

[0069] Figure 7 is a representation similar to Figure 5 at a third time point;

[0070] Figure 8 is a view similar to Figure 5 at a fourth time point;

[0071] Figure 9 is a plan view of the device of Figures 1-3 at a first time during operation of a slightly modified alignment unit;

[0072] Figure 10 is a view similar to Figure 9 at a second point in time;

[0073] Figure 11 is a view similar to Figure 9 at a third time point;

[0074] Figure 12 is a representation of an HMI of the device of Figures 1-3;

[0075] Figure 13 shows a path-over-time diagram and a speed-over-time diagram of two transport devices of the rotary module of Figures 1-3 in a first operating mode of the rotary module;

[0076] Figure 14 is a view similar to Figure 13 in a second operating mode of the rotary module;

[0077] Figure 15 is a schematic representation of the position and orientation of folding box blanks during operation of the apparatus of Figures 1-3 according to the second operating mode of Figure 14;

[0078] Figure 16 is a view similar to Figure 15 for the first operating mode of Figure 13; and Figure 17 is a schematic view of the movement lines on a folding box blank with multiple application areas.

[0079] Description of the implementation examples

[0080] In the following, functionally equivalent elements and regions in different figures bear the same reference symbols. Furthermore, for the sake of simplicity, not all reference symbols are shown in all figures.

[0081] Figures 1-3 show a device 10 for processing folding box blanks 12, comprising a feed device 14, a device for rotating a folding box blank 12 in the form of a rotary module 16, and an alignment unit 18. A transport direction or process direction of the folding box blank 12, in which the latter is transported by the feed device 14, the rotary module 16 arranged downstream of the feed device 14, and the alignment unit 18 arranged downstream of the rotary module 16, is indicated by an arrow 20. It is understood that the device 10 may also include further process stations, which, however, are not shown or described here.

[0082] In this exemplary embodiment, the feed device 14 comprises a roller conveyor 22 on which the folding box blank 12 lies, as well as two laterally spaced-apart conveyor belts 24 which act on the folding box blank 12 from above against the roller conveyor 22. The length of the area of ​​each conveyor belt 24 which comes into contact with the folding box blank 12 can be adapted to the geometry of the folding box blank 12 by displacing two deflection rollers (not shown). Such feed devices 14 are known to those skilled in the art. Therefore, a detailed explanation of the feed device 14 is omitted here.

[0083] The rotary module 16 is arranged directly behind the feed device 14, as viewed in the process direction 20. It comprises a first transport device 26R, which is on the right as viewed in the process direction 20, and a second transport device 26L, which is on the left as viewed in the process direction 20, each of which has a pair of wheels comprising a lower driven drive wheel 28 and an upper non-driven counter wheel 30.

[0084] With respect to the process direction 20, the first transport device 26R and the second transport device 26L are arranged laterally spaced from one another or laterally offset from one another transversely to the process direction 20. Details of the first transport device 26R and the second transport device 26L will be explained in more detail later. At this point, it should only be mentioned that the two

[0085] Driving wheels 28 with different

[0086] peripheral speeds. This allows a desired rotation of the folding box blank 12 about a rotation axis perpendicular to the plane of the drawing in Figure 3 to be effected.

[0087] Parts of the alignment unit 18 are shown as examples behind the rotary module 16, as seen in the process direction 20, in Figures 1-3. Shown are two lower conveyor belts 32 in this case and rows of pressure rollers 34 arranged above the conveyor belts 32. The conveyor belts 32 move the folding box blank 12 away from the rotary module 16 in the process direction 20. The alignment unit 18 also includes alignment strips 36 arranged to the side of the conveyor belts 32 and the pressure rollers 34. The folding box blank 12 can be aligned with a lateral edge on these strips after rotation in the rotary module 16 and during transport in the alignment unit 18.

[0088] The device 10 also includes infeed rollers 38 that are adjustable in the process direction 20 and can guide the folding box blank 12 through the rotation module 16 immediately after rotation. They are adjustable because the "impact point" of the folding box blank 12 after rotation in the rotation module 16 depends on the geometry of the folding box blank 12 and the rotation law used, i.e., the shape of a line of motion described in more detail below.

[0089] From Figure 4 it can be seen that the right-hand transport device 26R and the left-hand transport device 26L are each designed essentially identically to one another, but are arranged in mirror image and laterally spaced apart from one another (distance D) relative to the process direction 20.

[0090] Each of the transport devices 26R, 26L comprises a driven drive wheel 28, a controllable drive 42 which drives the drive wheel 28, and a non-driven counter wheel 30. In the present case, the counter wheel 30 is movably mounted on a parallelogram-like rocker 46 in a direction indicated by a double arrow 48. The rocker 46, in turn, is mounted on a machine frame 50. The advantage of such a parallelogram-like rocker 46 is that the counter wheel 30 is not tilted during compression. In principle, however, other options for the movable mounting of the counter wheel 30 are also conceivable, for example a simple linear guide. Alternatively or additionally, the surface of the counter wheel 30 and / or the drive wheel 28 can also be made of an elastically flexible material, for example rubber or the like.

[0091] In order to generate a uniform and controlled contact force between the counter wheel 30 and the drive wheel 28, a preload is preferably generated via a preload device or a spring device and / or a damper. In the present case, these functions can be implemented by way of example by a preload or spring and / or damping device 52, which is only indicated schematically. During operation, the counter wheel 30 presses the folding box blank 12 against the drive wheel 28 with a substantially constant force. As a result, due to the friction between the drive wheel 28 and the folding box blank 12, the forces required to move the folding box blank 12 (i.e. ultimately movement vectors) can be transmitted from the drive wheel 28 to the folding box blank 12 largely without slippage.For this purpose, the drive wheel 28 of the first and right-hand transport device 26R engages the folding box blank 12 at a first and right-hand approximately point-shaped contact point 54R, and the drive wheel 28 of the second and left-hand transport device 26L engages the folding box blank 12 at a second and left-hand approximately point-shaped contact point 54L.

[0092] It is understood that the term "approximately point-like" in the present context is by no means to be understood in the mathematical sense, as already explained in detail above. Rather, the use of the term "approximately point-like" is intended to express that the contact points 54R and 54L between the respective transport device 26R and 26L and the folding box blank 12 are very small compared to the dimensions of the folding box blank 12, namely in both Cartesian directions of a plane of the folding box blank 12. Typically, the dimensions of the contact points 54R and 54L are at least one order of magnitude (factor 10) smaller than the maximum dimensions (length and width) of the folding box blank 12.

[0093] In this way, the first transport device 26R can exert a first and right movement vector 56R on the folding box blank 12 at the first approximately point-shaped contact point 54R or generate one on the folding box blank 12 (i.e. move the folding box blank 12 at the contact point 54R in accordance with the first movement vector 56R), which is characterized by a first direction and a first amount. If the first transport device 26R is stationary as seen in the process direction 20, the first approximately point-shaped contact point 54R is also stationary as seen in the process direction 20, but the first approximately point-shaped contact point 54R moves along the moving folding box blank 12.

[0094] The same applies to the second transport device 26L, the second approximately point-shaped contact point 54L, and the second motion vector 56L. The first direction of the first motion vector 56R is parallel to the second direction of the second motion vector 56L.

[0095] Each of the two drive wheels 28 is equipped with its own drive 42. Typically, the drive 42 is an electric motor whose rotational speed can be controlled within wide limits. Position-controlled drives 42 are particularly preferred. An example of a position-controlled drive 42 is an electric servomotor, for example, a PSM motor with a closed-loop encoder system. In this way, the magnitudes and signs of the motion vectors 56L and 56R can be controlled very precisely.

[0096] The device 10 also includes a control device 58, for example a computer, with a microprocessor, an HMI, for example in the form of a screen and / or a keyboard, a memory, and program code that can be executed by the microprocessor. The control device 58 receives signals from a plurality of sensors, of which only one is shown in the present case with the reference number 60, which in the present case is arranged, by way of example, above the two transport devices 26R and 26L. The sensor 60 can, for example, be an optical sensor that detects when a front edge 62 of the folding box blank 12 reaches a specific position within the device 10. Contact switches or other types of sensors are also possible.

[0097] A method according to which the device 10 and in particular the rotary module 16 can be operated will now be explained with reference to Figures 5 to 8.

[0098] Figure 5 shows a folding box blank 12 which is still on the roller conveyor 22 of the feeding device 14 and which has not yet reached the rotating module 16 or the transport devices 26R and 26L with the drive wheels 28 and the counter wheels 30. In Figure 8 the same folding box blank 12 is shown rotated by 90°. It has passed the rotating module 16 and is now in the alignment unit 18. The folding box blank 12 which has been rotated by 90° compared to Figure 5 lies with its previous front edge 62 on the left-hand alignment bar 36 of the alignment unit 18 in the figures. This previous front edge 62 is therefore now the left edge of the folding box blank 12 as seen in the process direction 20.

[0099] In Figure 5, two virtual lines 64L and 64R are drawn on the folding box blank 12. These lines are specified by the control device 58 in order to implement a very specific and predetermined translational and rotational movement of the folding box blank 12 by the rotary module 16. The two movement lines 64R and 64L are to be virtually drawn on the folding box blank 12 by the two contact points 54R and 54L during the desired movement of the folding box blank 12 relative to the transport devices 26R and 26L.

[0100] The shape of the movement lines 64R and 64L will now be described using the example of the movement line 64R on the right in this case. The two movement lines 64R and 64L are parallel to one another and in this respect identical in terms of their shape. The movement line 64R comprises a first straight region B1. This is followed, by way of example and for simplicity's sake, by a circular region B2, i.e. curved with a constant radius (in practice it is preferred if the curved region has a radius of curvature that changes over the course of the movement line). Because the folding box blank 12 is to be rotated by 90°, the curved region B2 of the movement line 64R is a quarter circle with an angle of curvature of 90°. The area B2 is followed by a second straight area B3, which is comparatively short and through which the folding box blank 12 is moved out of the rotary module 16 in the process direction 20.

[0101] As can be seen from a comparison of Figures 5 and 8, the length of the straight region Bl depends on the geometry, for example the length of the folding box blank 12 and also on a lateral offset 66 (cf. Figure 3) of the folding box blank 12 relative to an alignment bar 36. If the folding box blank 12 is comparatively long and / or the left alignment bar 36 is positioned comparatively far to the left, this can be compensated for by selecting a comparatively long straight region Bl. If the folding box blank 12 is to lie against the right-hand alignment bar 36 as seen in the process direction, the straight region Bl of the movement line 64R would have to be selected to be somewhat shorter.

[0102] The movement lines 64R, 64L can be determined or specified in advance from the dimensions of the folding box blank 12 (length and width) as well as the spatial relationship of the roller conveyor 22 and the alignment unit 18 and / or the said lateral offset 66, taking into account the desired angle of rotation (usually 90°). As mentioned above, they are typically determined by the control device 58 depending on certain parameters, e.g., the dimensions of the folding box blank 12. The dimensions of the folding box blank 12 can be entered manually by an operator, or they are known to the control device 58 from a database.

[0103] In order to realize the desired lines of movement 64R and 64L, the two transport devices 26R and 26L or their drive wheels 28 or their drives 42 are controlled by the control device 58 at specific times at very specific speeds, i.e. in accordance with a specific speed-time curve. In order to generate the area B1 of the lines of movement 64R and 64L, the same peripheral speeds are generated at the two drive wheels 28. In order to generate the curved area B2 of the lines of movement 64R and 64L, different peripheral speeds are generated at the two drive wheels 28. In the present case, the drive wheel 28 of the right transport device 26R is operated at a higher peripheral speed than the drive wheel 28 of the left transport device 26L.

[0104] To create the rectilinear region B3, the two drive wheels 28 are again operated at the same circumferential speed. The drives 42 are controlled by the control device 58 such that they exhibit the desired individual circumferential speed at each point in time during the movement of the folding box blank 12 in the rotary module 16.

[0105] Figure 6 shows an intermediate step in which the folding box blank 12 has already been transported a certain distance in the direction of the alignment unit 18 by the transport devices 26R and 26L in the rotating module 16. The rotating movement has just begun in Figure 6, so that the folding box blank 12 has been rotated counterclockwise by an angle of approximately 15° relative to its initial position.

[0106] Figure 7 shows a further intermediate step, in which the rotation of the folding box blank 12 is almost complete. From the specified rotation angle of 90°, the folding box blank 12 has already completed a rotation of approximately 75°. This figure also clearly shows that the former front edge 62 is already very close to the left alignment strip 36.

[0107] In Figure 8, the rotation is complete. The folding box blank 12 has completed a rotation of 90° relative to its original orientation (see Figure 5). It rests with its former front edge 62 against the left alignment bar 36 and is moved further in the process direction 20 by the conveyor belts 32 of the alignment unit 18.

[0108] The method according to the invention is very simple to implement because only two transport devices 26R, 26L with individually controllable drives 42 of the drive wheels 28 are required. The overall length of the rotary module 16 according to the invention is very short. Viewed in the process direction 20, the overall length is only approximately as large as the diameter of the counter wheels 30 or the drive wheels 28.

[0109] Furthermore, the method according to the invention is also very advantageous because it allows for the correction of alignment errors. This requires no additional equipment.

[0110] 5 is not as well aligned as shown, but is instead guided towards the rotary module 16 on the roller conveyor 22 at an angle of, for example, 3° clockwise. It is then easily possible to compensate for this inclined position when the folding box blank 12 is rotated counterclockwise. This is achieved by the movement lines 64R and 64L, and in particular their curved region B2, having an angle of rotation of 90° + 3° = 93° instead of an angle of rotation of 90° counterclockwise. The drives 42 of the transport devices 26R and 26L are then driven accordingly, so that at the end of the rotary movement the inclined position of 3° clockwise is also compensated for and the folding box blank 12 arrives in the alignment unit 18 exactly aligned and rotated, as shown in Figure 8. Of course, this also applies if the

[0111] Folding box blank 12 arrives at the rotary module 16 tilted counterclockwise on the roller conveyor 22. The intended angle of rotation of 90° is then reduced by the tilt.

[0112] It is also possible to compensate for an undesired lateral offset using the rotation module 16 and the rotation method. If the first straight section Bl of the movement lines 64R and 64L is extended by the undesired offset, then this offset can be easily compensated. Of course, this compensation is also possible in the other direction by shortening the straight section Bl of the movement lines 64R and 64L.

[0113] As can be seen from Figures 9-11, the conveyor belts 32 and the pressure rollers 34 of the alignment unit 18 can be arranged at an angle relative to the respective alignment bar 36, wherein in the exemplary embodiment shown in Figures 9-11 only the left-hand conveyor belt 32 and the left-hand pressure rollers 34 are arranged at an angle, since in this exemplary embodiment alignment basically only takes place on the left-hand alignment bar 36. This has the effect that the folding box blank 12 is moved sideways (in this case to the left) against the respective alignment bar 36 (in this case the left alignment bar 36) during a movement in the alignment unit 18 in the process direction 20. This supports the alignment of the folding box blank 12 on the respectively desired alignment bar 36.

[0114] On the right side of Figure 12, an illustration of an HMI 68, for example a screen, of the control device 58 is shown, with various symbols and input options for various parameters. After these parameters have been entered, the movement lines 64R and 64L are then determined by the control device 58. On the left side of Figure 12, an example folding box blank 12 is shown, from which some of the parameters to be entered can be seen.

[0115] In section 68A, a distance D1 of the start of the left movement line 64L from an (initial) left edge 70 of the folding box blank is entered. In section 68B, a distance D2 of the start of the right movement line 64R from the left edge 70 of the folding box blank 12 is entered. In a section 68C, a length D3 is entered which corresponds to the distance from the initial front edge 62 of the folding box blank 12 from which the rotation of the folding box blank 12 is to start at the earliest. This is therefore the minimum length of the area Bl of the movement lines 64R and 64L.

[0116] In a section 68D, a distance D4 is entered that characterizes the end of the movement lines 64R and 64L or indicates when the rotation should be stopped at the latest. In a section 68E, a distance D5 is entered that characterizes or indicates where the left transport device 26L should be after rotation.

[0117] In a section 68F, a rotation correction in the form of an angle is entered, by which the orientation of the folding box blank 12 can be corrected or adjusted after rotation. In a section 68G, a correction for an (undesired) lateral offset 66 is entered. In a section 68H, the total length D6 of the folding box blank 12 (in the orientation before the rotation process) is entered.

[0118] From the input parameters, the control device 58 then determines the shape of the two movement lines 64R and 64L and converts these into corresponding control signals for the drives 42 of the two transport devices 26R and 26L. A first variant of the control signals is shown in Figure 13, which leads to the movement of the folding box blank 12 according to Figure 16. In the top of Figure 13, a distance S is plotted against time t, with a curve 72R describing the distance generated at the contact point 54R by the first right-hand transport device 26R and the corresponding movement vector 56R. A curve 72L describes the distance generated at the contact point 54L by the second left-hand transport device 26L and the corresponding movement vector 56L.In Figure 13 below, the corresponding circumferential speeds V are plotted against time t, with a curve 74R relating to the drive wheel 28 of the right-hand first transport device 26R and a curve 74L relating to the drive wheel 28 of the left-hand second transport device 26L. The circumferential speeds V correspond to the motion vectors 56R and 56L with their sign, direction, and magnitude.

[0119] A second variant of the control signals is shown in Figure 14, which leads to the movement of the folding box blank 12 according to Figure 15. It can be seen that successive folding box blanks 12 at the output of the rotary module 16 have a smaller distance from each other in the variant of Figures 13 and 16 than in the variant of Figures 14 and 15.

[0120] Fig. 17 shows an exemplary folding box blank 12 which has a plurality of application regions 100. To rotate the folding box blank 12, the application regions 100 on the folding box blank 12 are first identified. Subsequently, boundary conditions or parameters, in particular in the form of the distances and / or coordinates shown in Fig. 12, are specified depending on the identified application regions 100. Depending on the specified boundary conditions or parameters, the shape of the two movement lines 64R and 64L is determined, as previously described, and then converted into control signals. The curved regions B2 of the movement lines 64R and 64L in Fig. 17 are preferably formed at a distance from the application regions 100.Since the straight areas B1, B3 of the movement lines 64R and 64L have a constant speed, no impairment is to be expected when passing over the application areas 100. Due to the specification and / or determination of the movement lines 64R and 64L depending on the identified application areas 100, a reliable and reproducible rotation of the folding box blanks 12 can be provided while simultaneously protecting the application areas 100.

Claims

Patent claims 1. A method for rotating a folding box blank (12) by means of a rotating module (16), comprising the following steps: Providing at least one pair of transport devices comprising a first transport device (26R) and a second transport device (26L) such that they are laterally spaced from each other, Providing the first transport device (26R) in such a way that it can generate a first movement vector (56R) on the folding box blank (12) at a first approximately point-shaped contact point (54R) of the folding box blank (12), and Providing the second transport device (26L) in such a way that it can generate a second movement vector (56L) on the folding box blank (12) at a second approximately point-shaped contact point (54L) of the folding box blank (12), wherein the two movement vectors (56R, 56L) are arranged at least substantially parallel to one another and laterally spaced from one another, characterized in that the method further comprises the following steps: Specifying boundary conditions for determining two at least partially curved movement lines (64R, 64L), and / or Predetermining two movement lines (64R, 64L) which are at least partially curved, wherein the two contact points (54R, 54L) virtually draw the movement lines (64R, 64L) on the folding box blank (12) during the movement of the folding box blank (12) relative to the transport devices (26R, 26L), Controlling the amounts and / or signs of the two movement vectors (56R, 56L) such that the folding box blank (12) moves along the two predetermined and / or determined from the predetermined boundary conditions movement lines (64R, 64L).

2. Method according to claim 1, characterized in that before specifying the movement lines (64R, 64L) and / or before specifying the boundary conditions and determining the movement lines (64R, 64L), the method further comprises the following step: Identifying application areas arranged on the folding box blank (12).

3. Method according to claim 2, characterized in that the specification of the movement lines (64R, 64L) and / or the specification of the boundary conditions for Determination of the movement lines (64R, 64L) depending on the identified application areas takes place.

4. Method according to one of the preceding claims, characterized in that when using rotary drives (42) for the transport devices (26R, 26L), a curved region (B2) of the movement lines (64R, 64L) is generated by operating the rotary drives (42) of the transport devices (26R, 26L) at different circumferential speeds.

5. Method according to one of the preceding claims, characterized in that when using rotary drives (42) for the transport devices (26R, 26L), a straight-line region (B1, B3) of the movement lines (64R, 64L) is generated by operating the rotary drives (42) of the transport devices (26R, 26L) at the same circumferential speeds.

6. Method according to one of the preceding claims, characterized in that the movement lines (64R, 64L) comprise a straight-line region (B2) before and / or after a curved region (B1, B3).

7. Method according to one of the preceding claims, characterized in that a curved region of the two movement lines (64R, 64L) does not cross one, several or all application regions and / or spaced from one, several or all application areas.

8. Method according to one of the preceding claims, characterized in that a curved region of a first of the two movement lines (64R, 64L) with a larger radius crosses at least one application region and a curved region of a second of the two movement lines (64R, 64L) with a smaller radius does not cross the at least one application region and / or is formed at a distance from the at least one application region.

9. Method according to one of the preceding claims, characterized in that the position of the folding box blank (12) is detected, and in that at least one transport device (26R, 26L) is driven as soon as or after a front edge (62) of the folding box blank (12) has reached the transport devices (26R, 26L).

10. Method according to one of the preceding claims, characterized in that an inclined position of the folding box blank (12) is detected, and in that the inclined position of the folding box blank (12) is taken into account by a change in the angle of curvature of the curved region (B2) of the movement lines (62R, 64L) and consequently in the control of the drives (42).

11. Method according to one of the preceding claims, characterized in that a lateral offset (66) of the folding box blank (12) is detected before the rotation of the folding box blank (12) and the lateral offset (66) is compensated by a change in the shape of the movement lines (64R, 64L), preferably by a change in the length of a rectilinear region (Bl) of the movement lines (64R, 64L).

12. Method according to one of the preceding claims, characterized in that the curved region(s) (B1, B3) of the movement lines (64R, 64L) contain circular arcs.

13. Method according to one of the preceding claims, characterized in that the curved region(s) of the movement lines contain a changing radius of curvature.

14. Device (16) for rotating a folding box blank (12), having at least one pair of transport devices with a first transport device (26R) and a second transport device (26L), wherein the first transport device (26R) and the second transport device (26L) are laterally spaced from one another, wherein the first transport device (26R) can generate a first movement vector (56R) on the folding box blank (12) at a first approximately point-shaped contact point (54R), and wherein the second transport device (26L) at a second approximately point-shaped contact point (54L) can generate a second movement vector (56L) on the folding box blank (12), wherein the two movement vectors (56R, 56L) are arranged at least substantially parallel to one another and laterally spaced from one another, characterized in that the rotary module (16) has a control device (58) which is designed such that it can control the amounts and / or signs of the movement vectors (56L, 56R) such that the folding box blank (12) moves along two predetermined movement lines (64R, 64L) and movement lines (64R, 64L) which are at least partially curved and / or determined from predetermined boundary conditions and at least partially curved, which the two contact points (54R, 54L) during the movement of the folding box blank (12) relative to the transport devices (26R, 26L) on the folding box blank (12) draw virtually, moves.

15. Device (16) according to claim 10, characterized in that each of the transport devices (26R, 26L) comprises a pair of wheels (28, 30), preferably is formed by a pair of wheels, between which the folding box blank (12) can be guided.

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