METHOD OF MOVING A STACK OF PRODUCTS BY USE OF A ROBOT

Abstract

A method moves a stack of products by a robot. The robot has an articulated arm and at least one gripper disposed on the articulated arm to grip the stack of printed products and the stack of products selectively being turned. The method includes pivoting the stack of products through an effective angle α1< >180° and subsequently pivoting the stack through an effective angle α2=180°−α1 or pivoting the stack back through an effective angle α2=−α1. This method of moving stacks of products is performed in an automated way and in particular of depositing them in a turned or unturned arrangement.

Claims

1. A method of moving a stack of products by a robot, the robot containing an articulated arm and at least one gripper disposed on the articulated arm to grip the stack of products, the method comprising: pivoting the stack of products through an effective angle α1=90° into a vertical position; subsequently pivoting the stack through an effective angle α2=90° or pivoting the stack back through an effective angle α2=−90°; and selectively turning the stack in the vertical position about the vertical axis by the pivoting device.

2. The method according to claim 1, wherein the step of pivoting through the effective angle α1 is done using a pivoting device different from the robot.

3. The method according to claim 1, wherein the step of pivoting through the effective angle α1 occurs before a step of moving.

4. The method according to claim 1, which further comprises, subsequent to pivoting the stack through the effective angle α1 and prior to pivoting the stack through the effective angle α2, subjecting the stack to at least one process step selected from the group consisting of aligning the stack, straightening the stack, vibrating the stack, aerating the stack, and modifying the stack.

5. The method according to claim 1, wherein the stack of products is not in a horizontal position when it is aligned and/or straightened in a direction and/or straightened in two directions perpendicular to one another and/or vibrated and/or aerated and/or wherein a fanned-out stack of products is modified to become an unfanned stack of products.

6. The method according to claim 2, which further comprises taking over the stack of products from the pivoting device by the robot and then moving the stack of products.

7. The method according to claim 1, wherein the step of pivoting through the effective angle α2 occurs during a step of moving or between two movement portions or after the step of moving.

8. The method according to claim 1, wherein the step of pivoting through the effective angle α2 is done using the robot.

9. The method according to claim 1, wherein a side of the stack of products has at least four corners, and wherein during a step of moving, the stack of products is held at diagonally opposite corners.

10. The method according to claim 1, which comprises holding the stack of products in such a way that the stack of products sags in a diagonal direction.

11. The method according to claim 1, wherein a step of moving the stack of products includes moving the stack from a delivery of a machine for further processing of printed products to a pallet or to one of a plurality of pallets.

12. The method according to claim 1, which further comprises stacking multiple stacks of products on top of one another so as to be horizontally offset with one another and in multiple horizontal planes above one another to form a transport stack on a transport pallet.

13. The method according to claim 12, which comprises detecting a height of the transport stack by a sensor disposed on the robot.

14. The method according to claim 13, wherein the step of detecting the height comprises detecting the height as one of a single height value, a number of height values at different horizontal positions, of a height profile.

15. The method according to claim 14, wherein the articulated arm is moved without collision over the transport stack that has only partly been formed, and wherein a digital computer factors in a detected height as it controls a movement of the articulated arm.

16. The method according to claim 1, wherein a step of moving is done in a fully automated way in dependence on a selected deposit scheme and is adapted to a production speed of at least one machine for further processing.

17. The method according to claim 1, which comprises moving the robot arm within a protected zone.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0108] FIG. 1 is an illustration of a preferred exemplary embodiment of a device containing a robot for carrying out steps of a preferred embodiment of a method according to the invention;

[0109] FIG. 2 is a perspective view of a delivery of a machine for further processing;

[0110] FIGS. 3A and 3B are perspective views of preferred exemplary embodiments of the delivery;

[0111] FIGS. 4A to 4D are perspective views of preferred exemplary embodiments of a robot-guided gripping device;

[0112] FIG. 5 is a perspective view of a preferred exemplary embodiment of the gripping device;

[0113] FIGS. 6A and 6B illustrate preferred exemplary embodiments of deposit schemes;

[0114] FIG. 7 is a lateral view of a preferred exemplary embodiment of a transport stack; and

[0115] FIG. 8 is a flow chart for illustrating a method for moving a stack of products by means of a robot.

DETAILED DESCRIPTION OF THE INVENTION

[0116] In the drawings, corresponding features have the same reference symbols. Repetitive reference symbols have sometimes been left out for reasons of visibility. The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention.

[0117] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a preferred exemplary embodiment of a device preferably containing a robot and carrying out steps of a preferred embodiment of the method of the invention. FIG. 1 is a view from above.

[0118] A machine 70 for further processing, preferably a folder, which is only partly shown, is located in a position 74 and produces printed products 2, preferably printed and/or folded signatures 2, which are in the form of stacks 1 of products and are moved, e.g. conveyed, in a direction of transport 71 on a delivery 72. The action of the delivery, in particular the conveying action, may be controlled by a digital computer 80. A stack of products preferably contains a plurality of products resting on top of one another.

[0119] The digital computer 80, which is preferably connected to a network 81, may control the machine 70 for further processing and optionally further machinery; for instance, it may provide job data for the manufacturing of products. Job data may be provided via the network.

[0120] The delivery 72 may move the stacks 1 of products into a protected zone 73. A robot 10, preferably a robot containing an articulated arm 11 with multiple axes 12, for instance six axes, may be disposed in this zone. The robot may be a common industrial robot.

[0121] A gripping device 20 is disposed on the robot 10, preferably at the end of the articulated arm/“hand” 11 thereof. The gripping device may grip and hold stacks 1 of products to move them away from the delivery 72, preferably only within the protected zone. The movement 15 moves the stack 1 of products along a spatial curve to a transport pallet 62, where the stack of products is deposited and preferably positioned at a deposit location 60 in accordance with a deposit scheme 61. A number of pallets may preferably be provided within reach of the robot. The movement may comprise multiple movement portions 16. In between two movement portions, the gripping device may be rotated and/or pivoted, for instance. The rotating and/or pivoting may likewise occur during the movement.

[0122] A pivoting device 40 is preferably disposed at the end of the delivery 72. The pivoting device 40 may pivot the stacks 1 of products out of the horizontal 50, horizontal plane 53 or the horizontal position 52 into the vertical 54, the vertical plane 57 or the vertical position 56, respectively. The pivoting device may comprise two alignment elements 41, which are preferably movable in a horizontal direction, and/or straightening elements 42 for the stack of products. They may be embodied as surfaces, for instance plates.

[0123] The action, in particular the movement 15 and/or 16 of the robot 10, and/or the action, in particular the pivoting, of the pivoting device may be controlled by the digital computer 80.

[0124] FIG. 2 illustrates a preferred exemplary embodiment of a delivery of a machine for further processing. The delivery 72 may contain a plurality of rollers 76. The delivery may be a roller conveyor. Some of the rollers may be driven, for instance by motors 75. The digital computer 80 may control the process of conveying the stacks 1 of products 2 resting on top of one another. In this process, the stacks of products may be separated from one another in the direction of transport 71. The products 2 and therefore also the stacks 1 of products that have been formed preferably have four corners 5. Die-cut products may have more corners. If the products are folded products, their folding spines are preferably oriented to be parallel to the direction of transport.

[0125] FIGS. 3A and 3B illustrate preferred exemplary embodiments of the delivery, preferably containing the pivoting device, as they carry out steps of a preferred embodiment of the method of the invention. FIGS. 3A and 3B are perspective views.

[0126] FIGS. 3A and 3B illustrate the end of the folder 70 and the delivery 72 on which the stacks 1 of products are conveyed in the direction 71 of transport up to a pivoting device 40 (transporting step 101). Before being pivoted, the stacks of products and consequently the products 2 are preferably in a horizontal position 52.

[0127] The pivoting device 40 preferably contains grippers 43, for instance bars movable relative to one another, preferably one bar (closing “hold-down element”) on one side of the stack 1 of products and three bars on the other side of the latter. The pivoting device and/or the grippers thereof may be pivoted about a horizontal axis 51. The grippers, which are located below the stack 1 of products in FIG. 3A, may be positioned between the rollers 76 and may be pivoted out of this position.

[0128] FIGS. 3A and 3B illustrate sections of the robot 10 and the articulated arm 11 thereof. The robot is preferably movable in a horizontal direction on the floor and therefore positionable at various locations. The robot may, for instance, be supported on rollers. For example, rails may be provided.

[0129] FIGS. 3A and 3B illustrate the—preferably horizontally movable—alignment elements 41 and/or straightening elements 42.

[0130] A comparison between FIGS. 3A and 3B illustrates the pivoting movement/pivoting 110 through an effective angle α1 (pivoting step 110). In the illustrated example, the angle α1 is preferably 90°. After the pivoting step, the stack 1 of products is preferably in a vertical position 56. If the products 2 are folded products, in the vertical position, the spines are preferably at the top.

[0131] FIGS. 3A and 3B illustrate two sides 3 and 4. The robot 10 may preferably grip the pivoted stack 1 of products from side 3 or from opposite side 4. Side 3 may be referred to as the front side and side 4 as the back side. The selection of the side may be computer-controlled as a function of a deposit scheme.

[0132] The pivoting device may optionally be configured for rotation and may thus be rotated about a vertical axis 55. The stack of products may preferably be rotated through 180°. In accordance with this option, the robot 10 may always grip the pivoted stack 1 of products from the same side, preferably from side 3/the front side.

[0133] FIGS. 4A to 4D illustrate preferred exemplary embodiments of a robot-guided gripping device as it carries out steps of a preferred embodiment of the method of the invention. The figures are perspective views.

[0134] FIGS. 4A to 4D illustrate a flange 26 of the robot 10. A gripping device 20 for stacks 1 of products is preferably disposed on the flange. The gripping device is preferably disposed for rotation about an axis of rotation 13 (rotating step 142). The gripping device is pivotable about a pivoting axis 14 (further pivoting step 122 or back pivoting step 123). Both the axis of rotation and the pivoting axis may be a respective single axis 12 of the robot or respective multiple axes.

[0135] The gripping device 20 preferably contains two support arms: a first support arm 21 and a second support arm 23. The support arms are preferably perpendicular to one another. A first gripper 30 is preferably disposed on the first support arm so as to be movable in a first longitudinal direction 22. A second gripper 32 is preferably disposed on the second arm so as to be movable in a second longitudinal direction 24. The grippers may be driven by linear drives 25 to be adjusted as a function of the format.

[0136] The first gripper 30 preferably contains a first pair of gripper jaws 31 including an immobile gripper jaw 31a and a movable gripper jaw 31b. The movable gripper jaw may be driven by a linear drive 37. The second gripper 32 preferably contains a second pair of gripper jaws 33 including an immobile gripper jaw 33a and a movable gripper jaw 33b. The movable gripper jaw may be driven by a linear drive 37. Each one of the immobile gripper jaws may include a support element 34, preferably a support surface. The movable gripper jaws act to open and close the grippers.

[0137] The grippers 30 and a 32 grip the stack 1 of products 2 preferably at the corners 5 thereof and especially at corners 6 that are diagonally opposite one another (see diagonal 7 in FIG. 5).

[0138] In the example illustrated in FIG. 4A, the gripping device 20 grips the stack 1 of products that has been pivoted into a vertical position from side 4, i.e. from the back side, for instance. In other words, when the gripping device grips the stack of products, it is preferably located on side 4. To illustrate this, the transport direction 71 is indicated.

[0139] In the example illustrated in FIG. 4B, the gripping device 20 likewise grips the stack 1 of products that has been pivoted into a vertical position from side 4, i.e. from the back side, for instance.

[0140] A comparison between FIGS. 4A and 4B shows that either the first pair of corners 5 (top left and bottom right) or the other pair of corners 5 (bottom left and top right) may be gripped. The edges may be selected in a computer-controlled way and as a function of a deposit scheme.

[0141] In the example shown in FIG. 4C, the gripping device 20 grips the stack 1 of products that has been pivoted into the vertical from side 3, i.e. from the front side, for instance.

[0142] In the example shown in FIG. 4D, the gripping device 20 grips the stack 1 of products that has been pivoted into the vertical from side 3, i.e. from the front side, for instance.

[0143] A comparison between FIGS. 4C and 4D in turn shows that either the one pair of corners 5 (“top left” and “bottom right”) or the other pair of corners 5 (“bottom left” and “top right”) may be gripped. The edges may again be selected in a computer-controlled way and as a function of a deposit scheme.

[0144] The decision whether the stack 1 of products is gripped from side 3 or from side 4 and whether the one pair of corners 5 or the other pair of corners 5 is gripped in this process depends on how the stack of products is to be deposited—whether it is to be deposited in a turned or unturned arrangement and whether it is to be deposited in a rotated or unrotated arrangement. This in turn depends on a selected deposit scheme and the respective deposit position within this scheme. The digital computer 80 controls the gripping operation and the appropriate action of the robot 10 in accordance with the deposit scheme and deposit position. In this process, the side and the corners are selected accordingly.

[0145] Having been gripped and during the movement 130, in particular in between two movement portions 130a and 130b and preferably before being deposited (step 152), the stack 1 of products is pivoted through effective angle α2—either pivoted further (step 122) or pivoted back (step 123). When it is pivoted further, the stack of products is preferably deposited in a turned arrangement (turning step 140); when it is pivoted back, it is deposited in an unturned arrangement (non-turning step 141).

[0146] FIG. 5 illustrates a preferred exemplary embodiment of the gripping device as it carries out step 150 of letting a stack of products sag in accordance with a preferred embodiment of the method of the invention. FIG. 5 is a perspective view.

[0147] FIG. 5 shows the gripping device 20 with the two grippers 30 and 32. The grippers hold a stack 1 of products at diagonally opposite corners 6. The grippers are positioned/spaced apart from one another on the two support arms 21 and 23 as a function of the format of the stack of products and in such a way that the stack of products sags (step 150 of letting the stack sag). When the stack of products is deposited on the transport pallet 62 or on a transport stack 64 that has already been formed, the sagging diagonal 8 touches the pallet/the transport stack first. This allows the stack of products to be deposited in a precise way without disturbance and the open grippers 30 and 32 to be moved away from the stack of products by moving them in directions 58 perpendicular to one another. The digital computer 80 may control the opening and moving away.

[0148] FIG. 5 illustrates the two immobile gripper jaws 31a and 33a with two respective stop elements 35, in particular stop surfaces 35. When the stack 1 of products is deposited, the two support elements 34 (disposed below the stack of products and therefore not visible in FIG. 5) are preferably oriented in a horizontal direction, whereas the two respective (i.e. four) stop elements are preferably oriented in a vertical direction. The opening and closing of the grippers/the movement of the movable gripper jaws 31b and 33b occurs in a direction 38.

[0149] FIG. 5 illustrates a sensor 66, preferably disposed on one of the immobile (“lower”) gripper jaws 31a or 33a. The sensor may measure the distance to the pallet or to the transport stack that has already been formed or the height 65 and may transmit the measured value to the digital computer 80, allowing the latter to control a precise and in particular collision-free deposit.

[0150] FIG. 5 illustrates two further grippers 36, in particular suction gripper 36. They are preferably used to grip and hold intermediate layers 67.

[0151] FIGS. 6A and 6B illustrate preferred exemplary embodiments of deposit schemes.

[0152] FIGS. 6A and 6B are top views of an example of twelve stacks 1 of products. They were deposited in an order from stack 1 to stack 12.

[0153] At a respective corner of every stack of products, the gripping device 20 and flange 26 are shown as a circle. At two respective corners, the two grippers 30 and 32 are shown. Each one of arrows 58 indicates the directions into which the opened grippers are moved to release the stack of products.

[0154] Depositing the stacks 1 of products at the deposit positions 60 in accordance with the respective selected deposit scheme 61 allows the grippers 30 and 32 to move in the horizontal without colliding with stacks of products that have already been deposited before.

[0155] As shown in FIGS. 6A and 6B, what is referred to as a “chimney” 68, an empty space in the deposit scheme, may be created.

[0156] A comparison between FIGS. 6A and 6B shows that the deposit scheme may change. The deposit scheme is preferably changed in every new horizontal plane/layer of a transport stack to be formed. This improves the stability of the transport stack.

[0157] FIG. 7 illustrates a preferred exemplary embodiment of a transport stack created by the steps of “depositing”. FIG. 7 is a lateral view.

[0158] A first layer 63 of stacks 1 of products has been deposited on a transport pallet 62 in accordance with a first deposit scheme. On top of it, an intermediate layer 67 has been deposited. The robot may take intermediate layers off a neighboring stack of intermediate layers. Suction grippers 36 may be used for this purpose. A second layer 63 of stacks 1 of products is deposited on the intermediate layer in accordance with the second deposit scheme, which is preferably different from the first deposit scheme. As it can be seen, the edges of the stacks 1 of products may have a horizontal offset 69 relative to one another. This improves the stability of the transport stack.

[0159] As the gripping device 20 approaches the transport stack 64, the sensor 66 may measure the vertical distance 65 and the digital computer 80 may use the measured value to control the collision-free movement of the gripping device.

[0160] FIG. 8 illustrates a preferred exemplary embodiment of a flow chart. Optional steps are indicated by dashed lines.

[0161] The processing step (100) may comprise the manufacturing of folded products 2.

[0162] The transporting step (101) may comprise the transportation of stacks 1 of products into a direction of transport 71.

[0163] The separating step (102) may comprise the separation of stacks 1 of products in the direction of transport 71.

[0164] The stopping step (103) may comprise the stopping of the stack 1 of products at a pivoting device 40.

[0165] The pivoting step (110) may comprise a pivoting of the stack 1 of products 1 by means of a pivoting device 40, in particular through an angle α1=90°.

[0166] The aligning step (111) may comprise an alignment of the stack of products, preferably about a vertical axis. Alignment elements 41 may be used for this purpose.

[0167] The step of straightening (112) may comprise a straightening of the products 2. A straightening element 42 may be used for this purpose.

[0168] The vibrating step (113) may comprise a vibration of the stack 1 and consequently of the products 2.

[0169] The aerating step (114) may comprise an aeration of the stack 1 of products. The aeration may be attained by the vibration.

[0170] The modifying step (115) may transform a fanned-out stack of products 1 into an unfanned stack of products. Alignment elements 41 may be used for this purpose. Each one of them may be formed by a surface such as a plate with two chamfers.

[0171] The takeover step (120) may be done by the gripping device 20 and in particular the grippers 30 and 32 thereof. In the takeover, the stack of products may be transferred from the pivoting device 40 to the gripping device 20. The takeover may occur from side 3 or from side 4.

[0172] The holding step (121) may be done by the closed grippers 30 and 32.

[0173] The forward pivoting step (122) may be done by the robot arm 11, in particular through α2=90°.

[0174] The back pivoting step (123) may be done by the robot arm 11, in particular through α2=−90°. Further pivoting or back pivoting are preferably selected as a function of the deposit scheme.

[0175] The moving step/movement (130) is preferably done using the robot 10.

[0176] The partial moving step/movement portion (130a) and the partial moving/movement portion (130b) are preferably done using the robot 10.

[0177] The calculating step (131) is preferably done using the digital computer 80. The movement of the robot 10 may be calculated.

[0178] The controlling step (132) is preferably done using the digital computer 80. The movement of the robot 10 may be calculated.

[0179] The turning step (140) may be done by the robot arm 11, in particular through α1+α2=180°.

[0180] The non-turning step (141) may be done by the robot arm 11, in particular through α1+α2=0°.

[0181] The rotating step (142) may be done by the robot arm 11.

[0182] The step of letting sag (150) may be attained due to an adjustable distance between the two grippers 30 and 32.

[0183] The measuring step (151) of measuring the distance 65 and/or height 65 may be done by the sensor 66.

[0184] The depositing/stacking step (152) may be done by the robot arm 11. In this process, a predefined deposit scheme 61 may in particular be taken into consideration.

[0185] The following is a list of reference numerals and symbols appearing in the foregoing description with reference to the figures of the drawing: [0186] 1 stack of products [0187] 2 printed products, in particular folded printed products [0188] 3 side [0189] 4 opposite side [0190] 5 corners [0191] 6 diagonally opposite corners [0192] 7 diagonal [0193] 8 sagging diagonal [0194] 10 device, in particular robot [0195] 11 robot arm/articulated arm [0196] 12 axes [0197] 13 axis of rotation [0198] 14 pivot axis [0199] 15 movement/path [0200] 16 part of movement/part of path [0201] 20 gripping device [0202] 21 first support arm [0203] 22 first longitudinal direction [0204] 23 second support arm [0205] 24 second longitudinal direction [0206] 25 linear drive [0207] 26 flange [0208] 30 first gripper, in particular pliers-type gripper [0209] 31 first pair of gripper jaws [0210] 31a immobile gripper jaw [0211] 31b mobile gripper jaw [0212] 32 second gripper, in particular pliers-type gripper [0213] 33 second pair of gripper jaws [0214] 33a immobile gripper jaw [0215] 33b mobile gripper jaw [0216] 34 support element, in particular support pad [0217] 35 stop elements, in particular two stop surfaces [0218] 36 further gripper, in particular suction gripper [0219] 37 linear drive [0220] 38 movement to open/close the grippers [0221] 39 blower device [0222] 40 pivoting device [0223] 41 alignment elements [0224] 42 straightening element [0225] 43 gripper [0226] 50 horizontal [0227] 51 horizontal axis [0228] 52 horizontal position [0229] 53 horizontal plane [0230] 54 vertical [0231] 55 vertical axis [0232] 56 vertical position [0233] 57 vertical plane [0234] 58 two directions perpendicular to one another [0235] 60 deposit position [0236] 61 deposit scheme [0237] 62 base, in particular pallet [0238] 63 position of already deposited stacks of products [0239] 64 transport stack [0240] 65 height [0241] 66 sensor, in particular distance sensor or camera [0242] 67 intermediate layer [0243] 68 chimney [0244] 69 offset [0245] 70 machine for further processing, in particular folder [0246] 71 direction of transport [0247] 72 delivery [0248] 73 protected zone [0249] 74 position of a machine for further processing [0250] 75 drives [0251] 76 rollers [0252] 80 digital computer [0253] 81 network [0254] 100 processing step [0255] 101 transporting step [0256] 102 separating step [0257] 103 stopping step [0258] 110 pivoting step [0259] 111 aligning step [0260] 112 straightening step [0261] 113 vibrating step [0262] 114 aerating step [0263] 115 changing step [0264] 120 takeover step [0265] 121 holding step [0266] 122 step of further pivoting [0267] 123 step pivoting back [0268] 130 moving step/movement [0269] 130a partly moving step/movement portion [0270] 130b partly moving step/movement portion [0271] 131 calculating step [0272] 132 controlling step [0273] 140 turning step [0274] 141 step of not turning [0275] 142 rotating step [0276] 150 step of letting sag [0277] 151 measuring step [0278] 152 depositing/stacking step [0279] α1 (first) effective angle [0280] α2 (second) effective angle