METHOD AND AN APPLIANCE FOR SEPARATING INDIVIDUAL, FLAT, FLEXIBLE PRODUCTS FROM THE LOWER SIDE OF A STACK

Abstract

A method and an associated appliance for the cyclically controlled separating and singularizing of flat, flexible products from the lower side of a stack of such products and for conveying the singularized products away from the stack. The method includes the: gripping the lowermost product of the stack, separating the lowermost product from the stack lower side and transporting the product away from the stack. A first process condition is detected within cycle-linked measuring time window and a second process condition is detected within at least one further cycle-linked measurement time window in the same work cycle, by way of a single sensor in combination with a control device.

Claims

1. A method for the cyclically controlled separating and singularizing of flat, flexible products from the lower side of a stack of such products and for conveying the singularized products away from the stack, comprising the steps of: gripping the lowermost product of the stack, separating the lowermost product from the stack lower side and transporting the product away from the stack, wherein a first process condition is detected within cycle-linked measuring time window and a second process condition is detected within at least one further cycle-linked measurement time window in the same work cycle, by way of a single sensor in combination with a control device.

2. The method according to claim 1, wherein a third process condition is determined within a further cycle-linked measurement time window in the same work cycle.

3. The method according to claim 1, wherein in the respective measurement time window, at least one measured value is determined by the sensor and evaluated by the control device, and an extraordinary process step is initiated in a temporally subsequent process course given a deviation of the determined measured value from a predefined set value.

4. The method according to claim 1, wherein the sensor is an optical sensor for detecting a light signal.

5. The method according to claim 1, wherein the sensor is part of a light barrier with a light signal source and in particular with at least one reflector.

6. The method according to claim 5, wherein, from the measured values, it is determined whether the measuring beam path of the light signal has been interrupted between the light signal source and the sensor.

7. The method according to claim 5, wherein a reflector is located in each case in the reflecting position for reflecting the light signal towards the sensor, within the respective measurement time window.

8. The method according to claim 1, wherein within the measurement time window, it is examined whether the measuring beam path is interrupted by a product, which is correctly held by the transport element and moved through the measuring beam path.

9. The method according to claim 1, wherein, within the further measurement time window, in which, with a correct operation, a product intermediate space between two consecutive products of two work cycles is moved through the measuring beam path, it is examined whether the measuring beam path is interrupted, in particular by a product that is not correctly separated from the stack.

10. The method according to claim 9, wherein, within the further measurement time window, it is examined whether the measuring beam path is interrupted by a pulled-open, multi-page product or a surplus product.

11. An appliance for the cyclically controlled separation and singularization of flat, flexible products from the lower side of a stack of such products and for conveying the singularized products away from the stack, with a control device for the cyclically controlled operation of the appliance, wherein the appliance comprises a sensor, which in combination with the control device, is designed for detecting a first process condition within a cycle-linked measurement time window and for detecting a second process condition with a further cycle-linked measurement time window in the same work cycle, for the purpose of detecting irregularities on separating and transporting away the products.

12. The appliance according to claim 11, wherein the sensor is an optical sensor.

13. The appliance according to claim 12, wherein the appliance comprises a light barrier with a light signal source, and the optical sensor is part of the light barrier for receiving a light signal emitted by the light signal source.

14. The appliance according to claim 12, wherein the light barrier is a reflection light barrier which comprises at least one reflector for reflecting a light signal emitted by the light signal source, to the sensor.

15. The appliance according to claim 13, wherein the light signal source comprises a laser diode.

16. The appliance according to claim 11, wherein a transport device, by way of which the products are transported away from the stack, and the at least one reflector is arranged on a moved component of the transport device.

17. The appliance according to claim 13, wherein the light signal source of the light barrier is arranged such that the measuring beam path of a light signal emitted by the light signal source is interrupted by the product with the away-transport, within the measurement time window.

18. The appliance according to claim 13, wherein the light signal source of the light barrier is arranged such that the measuring beam path of a light signal emitted by the light signal source leads through the product intermediate space of two products within the further measurement time window.

19. The appliance according to claim 14, wherein at least one reflector or reflector section is arranged in a manner such that given an empty cycle, the light signal is reflected from the reflector or reflector section to the sensor within the measurement time window.

20. The appliance according to claim 14, wherein at least one reflector or reflector section is arranged in a manner such that on moving an intermediate product space through the measuring beam path, the light signal is reflected from the reflector or reflector section to the sensor within the further measurement time window.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0094] The subject-matter of the invention is explained in more detail by way of one embodiment example which is represented in the accompanying drawings. There are shown in:

[0095] FIG. 1 is a lateral view of an appliance according to the invention, at a first point in time of the cycle,

[0096] FIG. 2 is a lateral view of the appliance according to FIG. 1, at a second point in time of the cycle;

[0097] FIG. 3 is a lateral view of the appliance according to FIG. 1, at a third point in time of the cycle;

[0098] FIG. 4 is a further lateral view of the appliance according to FIG. 1, at the first point in time of the cycle,

[0099] FIG. 5 is a further lateral view of the appliance according to FIG. 1, at the second point in time of the cycle;

[0100] FIG. 6 is a lateral view of the appliance according to FIG. 1, with an empty cycle;

[0101] FIG. 7 is a lateral view of the appliance according to FIG. 1, with a pulled-open product;

[0102] FIG. 8 is a lateral view of the appliance according to FIG. 1, with a surplus pulled-off product.

DETAILED DESCRIPTION OF THE INVENTION

[0103] Basically, in the figures the same parts are provided with the same reference numerals.

[0104] FIGS. 1 to 8 show an appliance 1 for singularising flat, flexible printed products 2 from a stack 3 of such products. The appliance 1 is controlled by way of a control device 61.

[0105] The appliance 1 forms a stack space 4 for receiving a stack 3 of printed products 2. The stack 3 is arranged in a standing manner, which is to say the flat sides of the printed products 2 are orientated perpendicularly to the gravitational direction G. The product 2 of the stack 3 which is at the very bottom in the gravitational direction G lies with a flat side on the support surface device 6 supporting the stack 3 from below.

[0106] The appliance moreover includes a takeover circulatory apparatus 10 with a carrier wheel 13, which is rotatable in the circulating direction D about a rotation axis A. The carrier wheel 13 is arranged below the support surface and is driven via a drive.

[0107] The takeover circulatory apparatus 10 includes separating elements in the form of suction elements 11. These serve for detaching the products 2 from the lower side of the stack. The suction elements 11 are arranged on the carrier wheel 13 and are moved along a closed circulatory path by the rotating carrier wheel 13.

[0108] The suction elements 11 along their circulatory path are moved towards the lower side of the stack 3 and away from this again in a cyclically controlled manner by way of the rotating carrier wheel 13, for each gripping the lowermost printed product 2 in the stack 3.

[0109] The takeover circulatory apparatus 10 moreover includes transport elements in the form of grippers 12, which are likewise arranged on the carrier wheel 13. The grippers 12 as the suction elements 11, are moved along a closed circulatory path by way of the rotating carrier wheel 13.

[0110] A suction element 11 cooperates each with a gripper 12 and forms a pairing with this. In the present embodiment, in total four pairings of suction elements 11 and grippers 12 are arranged in a manner distanced from one another along the outer periphery of the carrier wheel 13.

[0111] A suction element 11 is led up to the free lower side of the lowermost printed product 2 of the stack 3 by way of rotating the carrier wheel 13, for separating a printed product 2 from the stack 3. The suction element 1 sucks or holds itself firmly on the front end section of the lowermost printed product 2 and bends this downwards away from the stack lower side. The lowermost product 2 is thus released or detached from the stack 3.

[0112] The bending-away and release of the printed product 2 downwards is effected via a superimposed movement, consisting of a pivot movement of the suction element 11 about a pivot axis as well as of a rotation movement of the suction element 11 with the carrier wheel 13, which continues to rotate.

[0113] In the further course of the separating procedure, the suction element 11 now transfers the product 2 onto the gripper 12 of the above-mentioned pairing, the gripper likewise being co-moved in a rotating manner with the carrier wheel 13.

[0114] The gripper 12 then pulls the gripped printed product 2 downwards away from the stack 3 in a complete manner.

[0115] The movement of the suction elements 11 and of the grippers 12 along their circulatory path, as well as any pivot movements of the suction elements 11 and of the grippers 12 about a pivot axis and the closure and opening movement of the grippers 12 is effected in each case in a cyclically synchronous manner.

[0116] If the printed products 2, which are pulled from the stack 3, are printed products 2 of several pages, each with a fold edge and a cut edge, then these are each bent away downwards and transported away with the fold in front.

[0117] The printed products 2 that are transported away from the stack 3 are subsequently transferred from the gripper 12 onto a belt conveyor 31.

[0118] According to the present embodiment example, an ejecting device 41 via which printed products 2a, 2b incorrectly pulled from the stack 3 can be ejected as yet described further below is integrated into the belt conveyor 31.

[0119] The ejecting device 41 is designed as a clamping conveyor with a first and a second conveying belt, which form a discharge gap. The printed products 2 are discharged from the belt conveyor 31 via the discharge gap.

[0120] The discharge gap is now adjustable between at least two positions. In a first position of the discharge gap, a printed product 2 is transferred to the takeover belt conveyor 51 (see FIGS. 4 and 5). In a second position of the discharge gap, a printed product 2 is ejected downwards (see FIGS. 1 to 3).

[0121] The position of the discharge gap can be adjusted by mechanical means, which are controlled by the control device 61.

[0122] The appliance 1 moreover includes a reflection light barrier for detecting irregularities on singularising the printed products 2 from the stack 3. The reflection light barrier is connected to the control device 61.

[0123] The reflection light barrier includes a light signal source 71 for emitting a light signal, as well as a sensor 72 for detecting the emitted light signal. The light signal source 71 and the sensor 72 are designed as a construction unit and are arranged on the appliance 1 in a stationary manner in a common housing. The light signal source 71 and the sensor 72 are arranged below the support surface of the support device 6 and above a horizontal plane leading through the rotation axis D of the carrier wheel 13.

[0124] The reflection light barrier moreover includes several first reflectors 73a, which are arranged on the carrier wheel 13. A first reflector 73a is each assigned to each gripper 12, wherein the first reflector is arranged in each case in the proximity of the gripper 12. As is explained further below, the first reflectors 73a serve for detecting an empty cycle.

[0125] The light barrier moreover includes several second reflectors 73b, which are likewise arranged on the carrier wheel 13. A second reflector 73b is assigned to each gripper 12 in a trailing manner. As is yet explained further below, the second reflectors 73b serve for detecting a product intermediate space 9, which is covered over by a printed product 2a, 2 which has not been correctly pulled from the stack 3.

[0126] The light signal source 71 of the light barrier is thus arranged such that a product 2, which is correctly transported away from the gripper 12, is moved through the measuring beam path 74 of the light signal and interrupts this, within a first cycle-linked measurement time window.

[0127] The light signal source 71 of the light barrier is moreover arranged such that a product intermediate space 9, which is correctly formed between two consecutive printed products 2 of two work cycles, is moved through the measuring beam path 74 of the light signal in a second, cycle-linked measurement time window.

[0128] In particular, three forms of irregularities can occur on singularising printed products 2 from a stack. According to a first form, no product 2 is separated from the stack 3 in the respective work cycle. This means that no product 2 is transported away in the respective work cycle. A so-called “empty cycle” is thus present.

[0129] According to a second form of an irregularity, the printed product 2a is arranged in the stack 3 the wrong way round, so that this is separated and transported from the stack 3 with the cut edge in front. This results in the product 2a being “pulled open”, i.e. being opened on separating from the stack 3.

[0130] According to a third form of an irregularity, two printed products are simultaneously separated from the stack 3, wherein only one printed product 2 is taken over by the gripper 12 and held by this. The product 2b, which is not held by the gripper 12, as a so-called “straying product” 2b is therefore transported away together with the product, which is correctly held by the gripper, however this being the case in a unguided and accordingly also uncontrolled manner.

[0131] The light barrier now serves for detecting at least the three forms of irregularities, which have been mentioned above.

[0132] On transporting away a printed product 2 separated from the stack 3, by way of the gripper 12, the product is moved downwards through the measuring beam path 74 of the light barrier. The product thereby interrupts the light signal, which is emitted by the light signal source 71.

[0133] A first cycle-linked measurement time window, in which measured values with respect to the detection of the light signal are determined by way of the sensor 72, is now set by the control device 61 during this procedure.

[0134] The first reflector 73a is arranged on the carrier wheel 13 in a manner such that this is located in a reflecting position in the first measurement time window. This means that the reflector 73a lies in the region of influence of the measuring beam path in the first measurement time window.

[0135] If the measuring beam path 74 is now interrupted by the correctly transported-away product 2 in the first measurement time window, then the sensor 72 accordingly receives no light signal. From this, the control device 61 recognises that a product 2 was correctly singularised from the stack 3 in the respective work cycle.

[0136] Since the measuring beam path 74 is led close to the gripper 12 in the first measurement time window, then it can also be deduced from the sensor measurement that the detected product 2 is also indeed correctly held by the gripper 12.

[0137] In the first measurement time window, the light signal is reflected back to the sensor 72 by the first reflector 73a if an empty cycle is now present, which is to say the gripper 12 includes no product 2.

[0138] The control device 61 recognises that an empty cycle is present by way of the receipt of the reflected light signal within the first measurement time window. Accordingly, the control device 61 can initiate, e.g., the ejection of an incomplete collection of a collecting device arranged downstream, the collection belong to the cycle.

[0139] A second, cycle-linked measurement time window during the movement of a product intermediate space 9 through the measuring beam path of the light barrier is set by the control device. The second reflector 73b is arranged on the carrier wheel 13 in a manner such that this reflector is located in the reflecting position within the second measurement time window.

[0140] If a product intermediate space 9 is now moved through the measuring beam path of the light barrier, then a light signal emitted within the second measurement time window is reflected back to the sensor 72 via the second reflector 73b.

[0141] On account of the receipt of the reflected light signal by the sensor 72, the control device 61 recognises that the product intermediate space 9 between two singularised printed products 2 of two consecutive work cycles is free.

[0142] If the product intermediate space 9 is now covered by a pulled-open or straying product, then the measuring beam path is interrupted by this product 2a, 2b. Accordingly, the light signal is not reflected to the sensor 72.

[0143] FIG. 7 by way of example shows how a pulled-open printed product 2a transported away by a gripper 12 of the takeover circulatory apparatus 10 covers the product intermediate space 9, which is subsequent in the transport direction F and thus covers the measuring beam path 74 of the light signal.

[0144] FIG. 8 by way of example shows how a so-called straying, surplus printed product 2b, which is transported away together with a printed product 2 of the same work cycle and which is correctly held by a gripper 12 of the takeover circulatory apparatus 10, covers the product intermediate space 9, which is subsequent in the transport direction F and thus covers the measuring beam path 74 of the light signal.

[0145] If the sensor 72 now detects no light signal and thus no product intermediate space 9 within the second measurement time window, then the control device 61 recognises an operational disturbance, such as the presence of a surplus printed product 2b or a pulled-open printed product 2a. The control device 61 can now initiate one or more of the steps, which have already been mentioned further above, such as an emergency stop, ejection of the printed product 2a, 2b concerned, or production of a warning notice.

[0146] Basically, yet further reflectors can be arranged on the carrier wheel 13, and these can detect yet further process conditions within further measurement time windows, in cooperation with the light signal source 71 and the sensor 72.

[0147] A continuous reflector can also be arranged on the carrier wheel 13, wherein a reflector section is assigned in each case to a measurement time window of a work cycle.