Folding box stack transfer device in a packaging machine and method for transferring a folding box stack in a packaging machine

Description

[0001] The invention relates to a method for transferring a stack of folding boxes in a packaging machine according to the preamble of claim 1.

[0002] In a packaging machine, and in particular a cartoning machine, a product is packaged in a folding box. The folding box initially appears as a flat, almost flat blank. A large number of corresponding flat folding boxes are stacked on top of each other to form a folding box stack, with the stacking direction running perpendicular to the flat folding boxes.

[0003] The folding boxes are stacked outside the packaging machine to form the folding box stack or are delivered already stacked. They must be gripped by a folding box stack transfer device and placed into a chute, from which they are removed individually and one after the other by the packaging machine at the bottom of the chute.

[0004] From DE 10 2012 107 984 A1 it is known to bring the stack of folding boxes into contact with a gripper jaw on each of its two end faces, usually in a horizontal orientation, i.e. with a horizontal stacking direction. The two gripper jaws are moved towards each other by means of a drive, whereby the stack of folding boxes is pressed together in the stacking direction and clamped between the gripper jaws. The clamping direction coincides with the stacking direction. When the gripping device is then lifted by means of a manipulator, for example an articulated arm robot, the stack of folding boxes is subjected to transverse forces and bending moments due to its own weight, which must be absorbed by the clamping force of the gripper jaws and the friction occurring between adjacent folding boxes. In addition, dynamic loads act on the stack due to the transfer of the stack of folding boxes.This can cause the folding boxes to shift relative to one another, causing the stack of folding boxes to lose its shape and making further handling difficult because it cannot be inserted into the shaft in this deformed state. If a folding box slips out of the stack of folding boxes, the stack of folding boxes loses its stability and all of the folding boxes fall out of the transfer device, which usually results in the packaging machine having to be stopped so that the individual folding boxes can be collected. To prevent this, according to DE 10 2012 107 984 A1, a suction device is provided on the gripper jaw holder, which acts on the stack of folding boxes. This additionally stabilizes the folding boxes during transfer.

[0005] A similar folding box stack transfer device is also known from US 2003 / 0120387 A1.

[0006] To securely pick up a stack of folding boxes, the gripper jaws must apply a compressive force along the longitudinal center line of the stack of folding boxes, and the suction device must be reliably brought into contact with the top of the stack of folding boxes. If stacks of folding boxes of different shapes and diameters are to be transferred with the stack of folding boxes transfer device, the shape and position of the gripper jaws and the suction device must be adjusted. This is time-consuming and costly.

[0007] CH 703 288 A2 describes and shows a method for transferring a stack of folding boxes in a packaging machine, in which a stack of folding boxes is clamped between two gripping jaws of a gripping device in a clamping direction that corresponds to the stacking direction of the stack of folding boxes. For this purpose, the two gripping jaws are brought into contact with the stack of folding boxes located in a box-like housing on opposite sides, whereupon the gripping jaws move together and the stack of folding boxes is clamped and lifted out of the box-like housing. A suction device can be provided, which is brought into contact with the surface of the stack of folding boxes and is activated during the transfer of the stack of folding boxes. The stack of folding boxes is then placed on a table and clamped between two holders.The gripping device is then rotated by 90° and the stack of folding boxes is gripped and clamped on its long sides and lifted from the table.

[0008] The repeated gripping, clamping, and setting down of the folding box stack not only increases the process time, but also creates the risk that the folding box stack will not be gripped and clamped correctly when removed from the box-like housing, as it only protrudes slightly from the box-like housing. US 5 425 565 A describes a method for transferring a folding box stack in a packaging machine according to the preamble of claim 1, in which the folding box stack is placed between two holding plates designed as finger plates. A transfer device is lowered onto the folding box stack in such a way that holding fingers slide into the finger plates from above and thus also hold the folding box stack between them. The holding fingers are moved together, whereby the folding box stack is compressed.The holding plates are pivoted, whereby the folding box stack is curved and pressed against an upper stop. In order to engage the holding fingers with the finger plates and to take over the folding box stack, a very precise movement is necessary, which is difficult to achieve in actual operation of the transfer device due to the working speed. Furthermore, the curvature of the folding box stack poses the risk of it becoming unstable, since the clamping force acting on the folding box stack only acts on its lower area. The object of the invention is to create a method for transferring a folding box stack in a packaging machine, in which secure gripping of the folding box stack is guaranteed even in the box-shaped housing.

[0009] This object is achieved according to the invention by the method according to claim 1. It is provided that the folding box stack is compressed and pre-tensioned in the stacking direction by means of at least two pressure elements before the gripping jaws are applied, and that the suction device is then lowered onto the folding box stack by means of the adjusting device after the folding box stack has been clamped between the gripping jaws by means of the clamping device.

[0010] It is provided that the suction device is brought into contact with the surface of the folding box stack and that the suction device is activated at least temporarily and in particular continuously during the transfer of the folding box stack. The suction device is lowered onto the folding box stack by means of an adjusting device only after the folding box stack has been clamped between the gripping jaws by means of the clamping device. This ensures that the suction device comes into contact with the already compressed folding box stack. In particular, it can be provided that the suction device is activated and sucks in and stabilizes the folding box stack before the folding box stack is lifted by means of the transfer device.

[0011] According to the invention, the suction device is brought into contact with the folding box stack only after the folding box stack has been clamped or compressed by means of the gripping jaws. This has the advantage that the surface of the folding box stack that comes into contact with the suction cups is preferably clamped together in an airtight manner, thus improving the effectiveness of the suction device.

[0012] Depending on the shape and design of the folding boxes, the extent to which the stack of folding boxes can be compressed varies greatly. To ensure that the stack of folding boxes can be reliably picked up, compressed, and clamped by the gripping jaws, the invention provides that the stack of folding boxes is pre-tensioned to a predetermined extent in the stacking direction by means of at least two pressure elements before the gripping jaws are applied.

[0013] In one possible embodiment of the invention, it can be provided that the stack of folding boxes is arranged in a box-shaped, upwardly open housing or crate and is removed from the housing or crate by means of the transfer device. It can be provided that the pressure elements penetrate the housing or crate wall from the outside at the end faces of the stack of folding boxes. In this way, it is possible to apply a pre-tensioning force to the stack of folding boxes located in the housing or crate, compressing the stack of folding boxes. In this state, the end faces of the stack of folding boxes are lifted from the wall of the housing or crate, so that the gripping jaws can engage in the space thus formed and come into contact with the end faces of the stack of folding boxes. The stack of folding boxes is then further compressed and clamped by means of the gripping jaws.

[0014] The suction device preferably consists of several suction cups arranged one behind the other in the clamping direction, which are activated simultaneously, for example. Alternatively, a suction pad with the aforementioned structure can also be used.

[0015] The folding box stack is contacted and pressed together by means of the gripping jaws, preferably at its end faces. If such a folding box stack is lifted without the action of the suction device, the greatest bending moments occur in the middle of the folding box stack as a result of the dead weight of the folding box stack. It is therefore preferably provided that the suction device, i.e. at least one of the suction cups and in particular two or three suction cups and / or the suction pad, are brought into contact with the surface of the folding box stack in the middle region of the length of the folding box stack when it is clamped between the gripping jaws. In particular, the suction cup(s) and / or the suction pad can be arranged in the two middle quarters of the length of the folding box stack in its compressed state.

[0016] A folding box stack transfer device is characterized in that the suction device can be adjusted relative to the gripping jaws by means of an adjusting device such that the suction device can be brought into contact with or out of contact with the surface of the preferably mentioned or compressed folding box stack.

[0017] The invention is also based on the basic idea of ​​supporting the folding box stack during the transfer process, at least temporarily and preferably continuously, by additional bearings. For this purpose, a suction device is provided which is brought into contact with the surface of the folding box stack and then activated, thereby additionally holding the folding box stack. The suction device is adjustable relative to the gripping jaws by means of the adjusting device. By adjusting the relative position between the gripping jaws on the one hand and the suction device on the other hand, simple adaptation to the geometry of the folding box stack to be picked up is possible. The gripping jaws can be aligned with the line of action of their clamping force on the longitudinal center axis of the folding box stack, and the suction device can be brought into contact with the top side of the folding box stack, preferably subsequently.In this way, an optimal position of the line of action of the clamping force of the gripping jaws and a good contact of the suction device on the top of the folding box stack are ensured.

[0018] The suction device can be adjusted perpendicular to the clamping direction of the gripping jaws using the adjustment device. The clamping direction of the gripping jaws preferably corresponds to the stacking direction of the folding box stack. In its compressed, clamped state, the folding box stack has a structured outer surface formed by the stacked folding boxes and has a groove-like structure. It has been shown that the unevenness of the outer surface can be compensated for by the appropriately dimensioned suction device, so that a high holding force can be transmitted between the suction device and the folding box stack.

[0019] The stack of folding boxes can be aligned horizontally immediately before being picked up by the transfer device so that a horizontal stacking direction is created and all folding boxes are aligned vertically and resting with their lower edge on a support surface. When such a stack of folding boxes is pressed together by the gripping jaws at its opposite end faces and clamped between the gripping jaws and then the transfer device lifts the stack of folding boxes, vertically downward transverse forces and bending moments act on the stack of folding boxes as a result of the dead weight of the stack of folding boxes and as a result of dynamic effects. Before the stack of folding boxes is lifted, the suction device is brought into contact with the upper side of the horizontally aligned stack of folding boxes and activated, preferably from above, so that additional support is provided, particularly when the stack of folding boxes is lifted.

[0020] The suction device can be a single, preferably linear suction cup extending in the longitudinal direction of the folding box stack, i.e., in the stacking direction. Alternatively, it is possible to provide several individual suction cups, which are preferably arranged at a distance from one another. The suction cups can be arranged in at least one row extending in the clamping direction and are preferably supplied by a common vacuum source.

[0021] The clamping device can have a suction pad that can be brought into contact with the stack of folding boxes. The use of a suction pad offers the advantage of allowing suction forces to be applied over a large or even full surface of the stack of folding boxes, and of compensating for unevenness in the stack of folding boxes through elastic deformation of the suction pad.

[0022] The absorbent pad preferably consists of an elastically deformable, foamed plastic material and in particular of foam.

[0023] The absorbent pad can be made of an air-permeable material, for example an open-pored or open-cell foam, whereby additional openings can also be formed in the absorbent pad.

[0024] If the absorbent pad is made of an air-impermeable material, a plurality of through-openings should be formed in the absorbent pad, which are designed in particular as through-holes and are preferably arranged in a regular grid or pattern.

[0025] An articulated arm robot or a so-called collaborative robot (COBOT) can be used as a manipulator by means of which the transfer movement for the folding box stack is carried out.

[0026] The two gripper jaws can be moved toward each other and away from each other to release the stack of folding boxes. This movement can be achieved hydraulically, pneumatically, or by means of an electric motor, such as a servo motor. One gripper jaw can be fixedly attached to a longitudinal beam, while the other gripper jaw can be held on the longitudinal beam and adjusted along a linear guide.

[0027] The suction device is preferably mounted on a holder that can be moved toward the folding box stack by means of the adjustment device and retracted from the folding box stack. Preferably, the adjustment device is also mounted on the longitudinal beam supporting the gripping jaws.

[0028] The suction device can be adjusted pneumatically, hydraulically or by means of a motor, in particular a servo motor.

[0029] In a preferred embodiment of the invention, a box-shaped housing is provided in which the stack of folding boxes can be accommodated. At least one pressure element can be arranged on each of the opposite sides of the housing. The pressure elements can be used to apply a clamping force to the stack of folding boxes arranged in the housing, compressing the stack of folding boxes.

[0030] Preferably, the pressure elements are arranged on the outside of the housing and each penetrate a wall of the housing, so that the interior of the housing is free of the pressure elements when the stack of folding boxes is inserted into the housing.

[0031] The pressure elements can be adjustable bolts that penetrate the wall of the housing.

[0032] Preferably, the pressure elements are adjustable by means of a drive device, which can be an electric motor, a hydraulic drive, or a pneumatic drive. Further details and features of the invention will become apparent from the following description of an exemplary embodiment with reference to the drawing. They show: Fig. 1 is a perspective view of a folding box stack transfer device according to the invention, Fig. 2 is an enlarged view of the gripping device and the folding box stack in a 1st phase of transfer, Fig. 3 is an enlarged view of the gripping device and the folding box stack in a 2nd phase of the transfer device, Fig. 4 is an enlarged view of the gripping device and the folding box stack in a 3rd phase of transfer, Fig. 5 is an enlarged view of the gripping device and the folding box stack in a 4th phase of transfer, Fig. 6 is an enlarged view of the gripping device and the folding box stack in a 5th phase of transfer, Fig. 7 is an enlarged view of the gripping device and the folding box stack in a 6th phase of transfer and Fig. 8 is a gripping device with an alternative design of the suction device.

[0033] Figure 1shows a view of a folding box stack transfer device 10, by means of which a folding box stack FSS can be transferred, which is accommodated in a box-shaped housing 22 in a horizontal orientation, i.e. with a horizontal stacking direction H. Two through holes 23 are formed in each of the side walls of the housing 22, against which the folding box stack FSS rests with its end faces. A pressure element 24 is arranged outside the housing 22 on the opposite end faces of the folding box stack FSS. Each pressure element 24 penetrates the wall of the housing 22 at the through holes 23 and can be moved in the direction of the folding box stack FSS. For this purpose, each pressure element 24 is assigned a drive device 33, by means of which drive device 33 an adjusting force can be applied to the pressure element 24, as indicated by the arrow M.When the pressure elements 24 arranged on opposite sides of the housing 22 are moved towards each other, the folding box stack FSS can be compressed or pre-tensioned in the stacking direction H.

[0034] The folding box stack transfer device 10 is intended to remove the folding box stack FSS from the box-shaped housing 22 and insert it into a vertically aligned shaft V from above, as indicated by the arrow A.

[0035] The folding box stack transfer device 10 has a manipulator 15 in the form of a multi-joint robot 16, which can be configured as a collaborative robot (COBOT). The manipulator 15 carries a gripping device 11 at its front end for receiving the folding box stack FSS. The gripping device 11 comprises a longitudinal beam 14, to one end of which a gripping jaw 12 is fixedly attached. A linear guide 17 is arranged on the underside of the longitudinal beam 14, on which another gripping jaw 13 is slidably mounted. By means of a drive 18, the additional gripping jaw 13 can be moved along the linear guide 17, so that the distance between the gripping jaws 12 and 13 can be increased or decreased.

[0036] Furthermore, a suction device 19 is provided with a rod-shaped holder 21, which extends parallel to the longitudinal member 14 and carries on its underside four suction cups 20 arranged next to one another in a row at a distance. The suction cups 20 can be subjected to negative pressure, as indicated by the arrow L (see Fig.2 ) is indicated.

[0037] In particular Figure 6 shows, the holder 21 is connected to an adjusting device 25 via a holding plate 27, which has two vertical holding rods 26, which are slidably guided in a bearing block 29. Between the bearing block 29 and the holding plate 27, a push rod 28 is effective, by the activation of which the holding plate 27 together with the suction device 19 attached thereto can be lowered and raised towards the top of the folding box stack FSS, as indicated by the double arrow T in Figure 2 is indicated.

[0038] In the following, the individual phases of transferring the stack of folding boxes FSS from the box-shaped housing 22 into the shaft V are described using the Figures 2 to 7 be explained in detail.

[0039] Figure 2 shows the starting position, wherein the folding box stack FSS is arranged in a horizontal orientation, i.e. with a vertical stacking direction H in the upwardly open housing 22 and rests with its end faces F 1 and F 2 against the side walls of the housing 22. In order to move the end faces F 1 and F 2 of the folding box stack FSS away from the side walls of the housing 22, the drive devices 33 are activated, whereby the pressure elements 24 are introduced from the outside through the through holes 23 of the housing 22 and the two pressure elements 24 are moved towards each other, whereby the folding box stack FSS is compressed within the housing 22 in the stacking direction H by a small amount, as shown in Figure 3is shown. In this case, the end faces F 1 and F 2 are lifted off the side walls of the housing 22, so that gaps 34 are formed between the end faces F 1 and F 2 and the side walls of the housing (see Fig.3 ).

[0040] The gripping device 11 is then positioned above the housing 22 such that the vertical gripping jaws 12, 13 are each located exactly above one of the gaps formed between the end faces F 1 and F 2 and the side walls of the housing 22. The gripping device 11 is then lowered by means of the manipulator 15 so that the gripping jaws 12 and 13 engage in the gaps 34 between the end faces F 1 and F 2 of the folding box stack FSS and the walls of the housing 22, as shown in Figure 4 The suction device 19 is still located at a distance above the folding box stack FSS.

[0041] In a further step, the drive 18 is activated, whereby the Figure 4 left gripping jaw 13 along the linear guide 17 to the Figure 4 right gripper jaw is moved towards. The gripper jaws 12 and 13 come into contact with the end faces F 1 and F 2 of the folding box stack FSS and press it together in the stacking direction H, so that the folding box stack FSS is clamped between the gripper jaws 12 and 13 under close packing, as shown in Figure 5 is shown. A clamping direction S coincides with the stacking direction H.

[0042] As soon as the gripping jaws 12 and 13 have reached their desired relative position and the folding box stack FSS is sufficiently compressed and clamped, the suction device 19 is lowered by activating the adjusting device 25 until the suction cups 20 rest on the surface of the folding box stack FSS, as shown in Figure 6is shown. Subsequently, the suction cups 20 are subjected to a negative pressure (arrow L) so that the folding box stack FSS is sucked by the suction cups 20. This state is shown in Figure 6 shown.

[0043] Subsequently, the manipulator 15 is activated, which pulls the gripping device 11 vertically upwards and thus removes the folding box stack FSS from the housing 22. In this, in Figure 7 In the state shown, the folding box stack FSS is clamped at its end faces F 1 and F 2 by the gripping jaws 12 and 13 and is additionally prevented from falling by the suction cups 20 placed on the upper surface of the folding box stack FSS. In this state, the folding box stack FSS can be aligned as desired by means of the manipulator 15 and inserted into the shaft V from above. The pressure elements 24 are retracted from the housing 22 by means of the drive devices 33, as shown in Figure 7indicated by the arrows M'.

[0044] Figure 8 shows an alternative embodiment of the suction device 19. In the previous embodiment, several individual suction cups were provided, which are now replaced by a suction pad 35, which can be made of foam. The suction pad 35 has a suction surface 35a on its underside, with which it can be placed over a large area or even over its entire surface on the top side of the compressed folding box stack FSS when the suction device 19 is lowered.

[0045] The absorbent pad 35 consists of an open-pored and thus air-permeable foam material, but in addition, through openings 36 can also be introduced into the absorbent pad 35.

[0046] On the side of the suction pad 35 facing away from the folding box stack FSS, a vacuum chamber (not shown) is formed in the holder 21, so that a vacuum can be generated on the suction surface 35a of the suction pad 35.

[0047] When the suction device 19 is lowered onto the top side of the folding box stack FSS in the manner mentioned, the suction pad 35 is pressed with its suction surface 35a against the top side of the folding box stack FSS and, after applying a negative pressure to the suction surface 35a, a large-area suction and holding force is applied to the folding box stack FSS.

Claims

1. A method for transferring a folding box stack (FSS) in a packaging machine, the folding box stack (FSS) being clamped in between at least two gripping jaws (12, 13) of a gripping apparatus (11) in a clamping direction (S) corresponding to the stack direction (H) of the folding box stack (FSS), and the gripping apparatus (11) then being transferred together with the folding box stack (FSS) by means of a manipulator (15), wherein the folding box stack (FSS) is compressed and prestressed in the stack direction (H) by means of at least two pressure elements (24) before the attachment of the gripping jaws (12), characterized in that a suction apparatus (19) being brought into contact with the surface of the folding box stack (FSS), and the suction apparatus (19) being activated at least temporarily during the transfer of the folding box stack (FSS), wherein the suction apparatus (19) is lowered onto the folding box stack (FSS) by means of an adjusting apparatus (25) after the folding box stack (FSS) is clamped in between the gripping jaws (12, 13) by means of the clamping apparatus (S).

2. The method as claimed in claim 1, characterized in that the prestressing of the folding box stack (FSS) takes place in a box-shaped housing (22).

3. The method as claimed in claim 2, characterized in that the pressure elements (24) are moved through the wall (22a) of the housing (22) and are adjusted.

4. The method as claimed in claim 3, characterized in that a folding box stack transferring apparatus (10), with a gripping apparatus (11) is provided which is arranged on an adjustable manipulator (15) and has at least two gripping jaws (12, 13) which can be moved toward one another in a clamping direction (S) and between which the folding box stack (FSS) can be clamped, the gripping apparatus (11) being assigned a suction apparatus (19) which can be adjusted by means of an adjusting apparatus (25) relative to the gripping jaws (12, 13) in such a way that the suction apparatus (19) can be brought selectively into or out of contact with the surface of the folding box stack (FSS), wherein a box-shaped housing (22) is provided, in which the folding box stack (FSS) can be received, and wherein at least one pressure element (24) is arranged on each opposed sides of the housing (22), wherein a clamping force which compresses the folding box stack (FSS) can applied by way of the pressure elements (24) to the folding box stack (FSS) which is arranged in the housing (22), wherein the pressure elements (24) each penetrate the wall (22a) of the housing (22).

5. The method as claimed in claim 4, characterized in that the pressure elements (24) have adjustable bolts (30) which penetrate the wall (22a) of the housing (22).

6. The method as claimed in one of claims 4 or 5, characterized in that the pressure elements (24) are adjusted by means of a drive apparatus (33).

7. The method as claimed in claim 6, characterized in that the drive apparatus (31) is formed by an electric motor or by a hydraulic drive or by a pneumatic drive.

8. The method as claimed in one of the claims 1 to 7, characterized in that, after the prestressing of the folding box stack (FSS) by means of the pressure elements (24), the gripping jaws (12, 13) are introduced into intermediate spaces (32) between the end sides (F1, F2) of the folding box stack (FSS) and the walls (22a) of the housing (22).

9. The method as claimed in claim 8, characterized in that the gripping jaws (12, 13) are introduced at the same time into the intermediate spaces (F1, F2).