Abstract:
An apparatus for supplying book blocks includes a feed conveyor to successively transport the book blocks with optional spacing. A buffer conveyor, arranged downstream of the feed conveyor and connected to a control unit, receives a plurality of the book blocks from the feed conveyor and transports them at a first speed, fitting against each other without a gap. A downstream clocking-in conveyor, coupled to the control unit, respectively receives a single book block from the buffer conveyor at the first speed, accelerates and transports the single book block from the first speed to a second speed. A downstream despatch conveyor includes a plurality of spaced apart pushers defining respective gaps between successive pushers. Each book is transported at the second speed toward the despatch conveyor and is inserted into one of the gaps between two successive pushers on the despatch conveyor.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority of Swiss patent application No. 02082/13 filed on Dec. 16, 2013, the subject matter of which is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Technical Field of the Invention 
         [0003]    The present invention relates to an apparatus and a method for clocking in book blocks which are optionally spaced apart and supplied successively on a feed conveyor to a despatch conveyor provided with pushers at predetermined distances, wherein the apparatus is provided with a control unit that is connected to the feed conveyor and the despatch conveyor. 
         [0004]    2. Prior Art 
         [0005]    With book binding machines, it is standard practice to transport the products to be processed with the aid of a clocked transport system through the machine. During the transport, the products are moved past different processing stations and are processed therein. To insert the products into the clocked transport system, the products must be prepared so that they can, be inserted individually and at the correct point in time, meaning clocked, into the transport system. 
         [0006]    An apparatus for regulating the supply of items to a packaging machine is known from German Patent Document DE 2346407, wherein this apparatus is provided successively arranged with a storage belt, a fast-moving belt for generating spacings, as well as a transport belt. This apparatus is suitable for clocking in items such as books and book blocks having different dimensions. The storage belt is provided with items fitting flush against each other, which are subsequently transferred to the faster-moving belt. The items are separated during this transfer, meaning they are pulled apart so that they are positioned at a distance to each other, wherein the spacing essentially corresponds to the spacing between the pushers on the following transport belt to which the items are finally transferred. Items having different lengths can be clocked in with the aid of this apparatus by running the storage belt at a higher or lower transport speed, depending on the length of the items. Methods of this type, however, are problematic when using book blocks composed of loose sheets and/or individual pages. If the book blocks are accelerated from the speed of the storage belt to the speed of the faster-moving belt, they can fall apart if the friction between the underside of the book block and the surface of the transport belt is higher than the friction between the sheets and/or the individual pages. 
         [0007]    An apparatus for inserting items into a packaging machine is known from German Patent Document DE 29504431 U1. A roller carpet transports the items that are optionally spaced-apart to a buffer or accumulation belt on which the items are accumulated, such that they fit flush against each other. The items are subsequently transported further via a separating belt, while fitting flush against each other, are separated at the end of this separating belt, and are subsequently conveyed further with the aid of a clocking-in belt to a packaging machine. For the transfer from the separating belt to the clocking-in belt, the front edge of an item is detected with the aid of sensors, particularly photo-electric cells, at the discharge end of the separating belt. The belt drive is operated or stopped so that the items are conveyed into the gaps between the pushers on the feed belt. This apparatus is suitable for use with items having a high friction between the contact face and the separating belt, and which do not sustain damage during accelerations occurring during the start-stop operation of the separating belt. Book blocks which are composed of individual loose sheets and/or pages can fall apart based on this type of acceleration. Additionally, the orientation of the sheets or the individual pages within a book block can change impermissibly. 
         [0008]    An apparatus for feeding individual sheets, stacked folded sheets, book blocks, books or similar items to a further processing machine is known from German Patent Document DE 202010001437 U1. With this apparatus, the items are successively transported onto a feed conveyor embodied as a first belt conveyor and provided at the downstream end with a blocking element for holding back the items or for releasing the items while synchronized with a receiving cycle. Arranged directly following the feed conveyor is a second belt conveyor which is operated at a higher speed than the first belt conveyor. The item in front is thus accelerated more when released by the blocking element than the following items, and the blocking element can be moved into the gap developing between the items. Furthermore arranged in the region of the feed conveyor is a pressure roller which rolls off the items and is provided with a reverse brake, wherein the pressure roller can prevent the transported items from bouncing back once they impact the blocking element. The pressure roller furthermore allows for a fast acceleration of the item positioned under the pressure roller, as soon as the item is released by the blocking element. During the transfer of the item from the first belt conveyor to the second belt conveyor, the acceleration of the item depends on the friction between the item and the second belt conveyor. If the friction is high, the item is strongly accelerated. In the case of a loose book block composed of sheets and/or individual pages, the danger thus exists that the book block can fall apart and/or the orientation of the sheets or the individual pages of the book block can change. With a low friction, on the other hand, it is not possible to reach high production speeds. Since the friction between the items and the second belt conveyor is determined by the material of the belt conveyor, the friction can only be changed through the arduous replacement of the material for the second belt conveyor. In addition, a great deal of time is needed to form the gaps between the items and for the stopping and releasing of the items by the blocking element. 
         [0009]    With the apparatuses according to the prior art, it is therefore not possible to ensure a secure arrangement of sheets and/or the individual pages of the book block while maintaining the required orientation. 
       SUMMARY OF THE INVENTION 
       [0010]    It is an object of the invention to make available a simple, cost-effective apparatus and a method which allow supplying book blocks at a high production speed to a despatch conveyor which may operate continuously or in a clocked mode. In the process, the arrangement of the book blocks should be maintained and/or the required orientation of the sheets or the individual pages in the book block should not change. 
         [0011]    The above and other objects are achieved by the provision of an apparatus for supplying book blocks, which in one embodiment comprises: a control unit; a feed conveyor coupled to the control unit to successively transport the book blocks with optional spacing: a buffer conveyor arranged downstream of the feed conveyor and connected to the control unit to receive a plurality of the book blocks from the feed conveyor and to transport the plurality of the book blocks at a first speed while fitting against each other without a gap; a clocking-in conveyor arranged downstream of the buffer conveyor and coupled to the control unit to respectively receive a single book block from the buffer conveyor at the first speed, accelerate the single book block from the first speed to a second speed and transport the single book block at the second speed; and a despatch conveyor arranged downstream of the clocking-in conveyor and including a plurality of spaced apart pushers defining respective gaps between successive pushers, wherein each book is transported at the second speed toward the despatch conveyor and is inserted into one of the gaps between two successive pushers on the despatch conveyor. 
         [0012]    According to one embodiment of the apparatus, a transfer conveyor that is connected to the control unit and can be driven with a variable speed is arranged downstream of the clocking-in conveyor and upstream of the despatch conveyor. In the process, at least one book block can be taken over with the speed of the clocking-in conveyor and can be transferred from the transfer conveyor to the despatch conveyor. A device for detecting the position and/or the format of the book block, in particular its dimensions in the conveying direction, is arranged in the region of the transfer conveyor, wherein a value resulting from the detection can be compared to a preset value stored in the control unit and the resulting value can then be used for varying the speed of the transfer conveyor. The resulting advantage is that by varying the speed of the transfer conveyor, book blocks can be transferred successively with even more precision into the gap between two successive pushers on the despatch conveyor. 
         [0013]    The clocking-in conveyor can be provided with a drive, wherein at least one sensor is arranged in the region of the clocking-in conveyor for detecting the position of the book block on the clocking-in conveyor, and wherein the drive and the at least one sensor are connected to the control unit. The drive of the clocking-in conveyor can thus additionally be accelerated or delayed, corresponding to the data transmitted by the sensor to the control unit for the position of the book block on the clocking-in conveyor. 
         [0014]    According to a different embodiment of the apparatus, the control unit may be connected to a rotation angle sensor, in particular to an incremental encoder of a drive for the despatch conveyor. The control unit can thus determine a desired position for the book block for each path section of the clocking-in conveyor and, if applicable, the transfer conveyor. A better preparation for clocking in the book blocks can furthermore be achieved in that the control unit can change the first speed of the buffer conveyor based on a deviation of the actual position of the book block, relative to its desired position. 
         [0015]    With a different embodiment of the apparatus and given a change in the speed of the clocking-in conveyor, the control unit can determine and/or detect during the operation a maximally permissible acceleration on the basis of product information for the book blocks to be processed. For the clocking-in operation, the apparatus can thus be operated with a maximum speed which allows for safe transport of the book blocks, without displacement of the sheets and/or the individual pages in the book block. 
         [0016]    According to yet another embodiment of the invention, the control unit is advantageously connected to a database in which additional product information is stored on the book blocks to be processed. 
         [0017]    With another embodiment of the apparatus, a nozzle configuration, including at least one nozzle, which is directed toward the clocking-in conveyor is arranged above the clocking-in conveyor and is connected to a gas reservoir. As compared to yet another possible embodiment, provided with an upper belt for pressing the book blocks against the clocking-in conveyor or provided with pressure rollers, the book blocks can thus be processed without involved adjustment and independent of their thickness. 
         [0018]    A read-out unit may be connected to the control unit and can furthermore be arranged in the region of the buffer conveyor, and can be used to detect identification marks on the book blocks, and to transmit the identification marks to the control unit. The buffer conveyor speed can be varied based on the detected identification marks on the book blocks, as well as based on additional data and in particular format data from a database, or based on an external memory, or from the identification marks themselves. A higher flexibility can thus be achieved for the apparatus, wherein it is possible to adapt to different features of the book block. 
         [0019]    According to another aspect of the invention, there is provided a method for supplying book blocks, which in one embodiment comprises: a) supplying the book blocks successively and optionally spaced-apart on a feed conveyor that is coupled to a control unit; b) transferring the book blocks to a buffer conveyor arranged downstream from the feed conveyor and coupled to the control unit; c) transporting the book blocks on the buffer conveyor at a first speed to fit against each other without a gap; d) transferring a single book block at the first speed from the buffer conveyor to a clocking-in conveyor arranged downstream from the buffer conveyor and coupled to the control unit to cause the single book block to be accelerated by the clocking-in conveyor from the first speed to a second speed; e) transporting the single book block at the second speed toward a despatch conveyor having pushers arranged at a specified distance relative to each other and coupled to the control unit; and f) transferring the single book block into a gap between two successively following pushers of the despatch conveyor. 
         [0020]    The control unit synchronizes the operation of the clocking-in conveyor with that of the despatch conveyor, such that the book blocks are transferred to the desired position between two successively following pushers on the despatch conveyor, without sustaining mechanical deformation or damage. 
         [0021]    One modification of the method ensues if at least one book block is transferred from the clocking-in conveyor to a downstream-arranged transfer conveyor and from this conveyor to the despatch conveyor. The position and/or the format of the book block is detected in the region of the transfer conveyor, in particular the dimensions of the book block in conveying direction. A value resulting from the detection is compared to a value stored in the control unit. The result of this comparison is then used to correspondingly vary the speed of the transfer conveyor, wherein successively conveyed book blocks can be transferred with even more precision into the gap between two successively following pushers on the despatch conveyor. 
         [0022]    In another embodiment, the transfer conveyor may supply at least one book block with the second speed to the despatch conveyor, wherein the speed of the clocking-in conveyor need not be increased to the speed of the despatch conveyor because the transfer conveyor can take over the book block at a low speed and can accelerate it to the speed of the despatch conveyor. 
         [0023]    According to a further modification of the method, a sensor, arranged in the region of the clocking-in conveyor and connected to the control unit, determines the position of the book block respectively transported on the clocking-in conveyor, wherein the control unit compares the detected position for the book block to a desired position and, in case of a position deviation, corrects the position of the book block through correspondingly triggering an increase in the acceleration of the clocking-in conveyor, up to a maximum permissible acceleration for the book block. An even more precise positioning of the book block between the pushers on the despatch conveyor can thus be achieved. 
         [0024]    According to a further embodiment, a read-out unit may be arranged in the region of the buffer conveyor and may be connected to the control unit for detecting identification marks on the book blocks and transmit the identification marks to the control unit. The speed of the buffer conveyor is then varied, based on the detected identification marks on the book blocks, as well as based on additional data, in particular format data from a database or an external memory, or from the identification marks themselves. A flexible adaptation of the transporting operation to the specific features of the book blocks is thus possible, in particular to the formats of the book blocks. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0025]    The invention is explained in further detail in the following with the aid of 
           [0026]    Figures, which show in: 
           [0027]    FIG.  1 —A first exemplary embodiment of the apparatus according to the invention; 
           [0028]    FIG.  2 —A second exemplary embodiment of the apparatus according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]      FIG. 1  represents a first exemplary embodiment of an apparatus  8  according to the invention, for which a feed conveyor  1 , a buffer conveyor  2 , and a clocking-in conveyor  3  are arranged successively in a row, in the conveying direction F and upstream of a despatch conveyor  5 . The despatch conveyor  5 , equipped with several uniformly spaced apart pushers  6 , transports book blocks  18  to a downstream arranged further processing machine, which is not shown herein, for processing the book blocks  18 . The time which passes until a following pusher occupies the position of a preceding pusher is viewed in this case as a cycle. The processing machine and/or the despatch conveyor can be operated continuously or pulsating, i.e., in a clocked operation. The pushers  6  of the despatch conveyor  5  are synchronized with the operating cycles of the further processing machine, meaning they are also clocked. A different apparatus for the clocked transport of the book blocks  18  can, of course, also be arranged downstream of the despatch conveyor  5  in place of a further processing machine. 
         [0030]    The feed conveyor  1  is embodied, for example, as a roller conveyor and is drive-connected to a first drive  10  which is preferably embodied as frequency-controlled asynchronous motor. A slip-torque conveyor may be used for the feed conveyor  1 , meaning a conveyor for which the propelling force for the book blocks  18  is lower than the frictional force between the rollers of the feed conveyor  1  and the book block  18 . The buffer conveyor  2  comprises a second drive  11  which can also be embodied as frequency-controlled asynchronous motor. Arranged in the region of the buffer conveyor  2  is a read-out unit  23  for identification of marks on the book blocks  18  and a sensor  20 , for example embodied as photo-electric cell, wherein the latter is preferably arranged above the downstream end of the buffer conveyor  2 . 
         [0031]    The clocking-in conveyor  3  comprises a drive  12  which is embodied as rotational-angle controlled motor. According to one preferred embodiment, a sensor  21  is arranged in the region of and possibly above the clocking-in conveyor  3 , which functions to detect the position of the book blocks  18  on the clocking-in conveyor  3 . According to yet another preferred embodiment, a nozzle configuration  31  is arranged above the clocking-in conveyor  3  and is connected to a gas reservoir  32 . The gas reservoir  32  can furthermore have a connection, not shown herein, to the control unit  22 . Of course, the clocking-in conveyor  3  can be operated with or without the sensor  21  and/or with or without the nozzle configuration  31 . The despatch conveyor  5  comprises a motor functioning as a drive  14  which is provided with a rotation angle sensor  15  in the form of an incremental encoder. 
         [0032]    All electrical devices  10 ,  11 ,  12 ,  14 ,  15 ,  20 ,  21 ,  23  of the apparatus  8  are connected to a joint control unit  22  to which product parameters for the book blocks  18  can be supplied via a database  22   a  or via manual input. 
         [0033]    The control unit  22  obtains the information needed to determine the position of the pushers  6 , relative to the actual rotational angle of the drive  14  for the despatch conveyor  5 , from the rotational angle sensor  15  and from data stored in its memory. With the aid of this information, the clocking-in conveyor  3  is driven, meaning it is accelerated to the speed v 2 , so that the respective book block  18  is inserted in the desired position into the gap between the pushers  6  on the despatch conveyor  5 . The book block  18  is finally clocked into the despatch conveyor  5  in that the pushers  6  move against the book block  18  and take over its transport on the despatch conveyor  5 . 
         [0034]      FIG. 2  shows a second exemplary embodiment of the apparatus  8  where a transfer conveyor  4  that is also connected to the control unit  22  is arranged downstream of the clocking-in conveyor  3  and upstream of the despatch conveyor  5 . The transfer conveyor  4  comprises a drive  13  which can be embodied as a frequency-controlled asynchronous motor or as a rotational-angle controlled motor. 
         [0035]    A device  30  that is connected to a position sensor for detecting the position and/or the format of the book block  18 , in particular its dimensions in conveying direction F, can furthermore be arranged in the region of the transfer conveyor  4 . The device  30 , which can be embodied as a camera or a laser curtain, may be arranged above the transfer conveyor  4 . 
         [0036]    The apparatus  8  of the second embodiment also optionally comprises the nozzle configuration  31 , which is connected to the gas reservoir  32 . 
         [0037]    For the operation of the apparatus  8  according to the first embodiment, several book blocks  18  are transported with the aforementioned conveying devices  1 ,  2 ,  3 ,  5 . These book blocks  18  can respectively be composed of loose or temporarily fixated sheets and/or individual pages, books and similar print products. The book blocks  18  can be provided with identification marks, such as RFID, barcode and the like. 
         [0038]    The irregularly spaced-apart book blocks  18  are initially transported by the feed conveyor  1  with a speed v 0  in the conveying direction F to the buffer conveyor  2  and are accumulated so that they fit flush against each other, meaning the gaps between the book blocks  18  are closed. The buffer conveyor  2  is operated with a first speed v 1 , which is lower than the speed v 0  of the feed conveyor  1 . 
         [0039]    The accumulated book blocks  18  are transported with the buffer conveyor  2  and the speed v 1  in the direction of the clocking-in conveyor  3  and are transferred to this conveyor. By adapting the speed v 1 , the book block  18  can be transferred earlier or later, so that the transfer to the clocking-in conveyor  3  occurs at the correct point in time. However, if a book block  18  cannot be made available at the correct point in time at the transfer location between buffer conveyor  2  and clocking-in conveyor  3 , the drive  11  of the buffer conveyor  2  is stopped and an empty cycle generated. The sensor  20  which is preferably arranged at the end of the buffer conveyor  2  in that case detects a front edge of a book block  18 , then transmits a corresponding signal to the control unit  22  which, in turn, activates the drive  12  of the clocking-in conveyor  3 , thereby ensuring that the clocking-in conveyor  3  is operated at the same or nearly the same speed as the buffer conveyor  2  during the transfer of the book block  18  from the buffer conveyor  2  to the clocking-in conveyor  3 . 
         [0040]    As soon as a book block  18  is positioned with its center of gravity in such a way on the clocking-in conveyor  3  that the book block  18  can be accelerated without slippage, the speed of the clocking-in conveyor  3  is increased up to a speed v 2  which essentially corresponds to the speed of the despatch conveyor  5 . As a result, the book block  18  is accelerated and separated, wherein the acceleration is selected such that a change or elimination of the orientation of the sheets and/or individual pages of the book block  18  is prevented and such that the book block  18  does not have any slippage, relative to the clocking-in conveyor  3 . 
         [0041]    The sensor  21 , which is preferably arranged above the clocking-in conveyor  3 , is used to detect the position of the book block  18  on the clocking-in conveyor  3 . The control unit  22  then compares the actually detected position for the book block  18  to its desired position. Deviations from this position can be corrected through a corresponding triggering of the drive  12 . For these corrections, the control unit  22  takes into consideration the underlying maximum permissible accelerations for the book block  18 . 
         [0042]    Reaching the second speed v 2  of the clocking-in conveyor  3  is necessary so that the book block  18  can be inserted into the space between two successive pushers  6  on the following despatch conveyor  5 . Once the book block  18  has reached the speed v 2 , the clocking-in conveyor  3  is operated with a constant speed and the book block  18  is transferred to the despatch conveyor  5 . Following the takeover by the despatch conveyor  5 , the respective pusher  6  is moved against the book block  18 , so that the book block  18  is transported in a clocked manner by this pusher  6  to the further processing machine, which is not shown herein. The operation of clocking the book block  18 , supplied on the feed conveyor  1 , into the despatch conveyor  5  is thus finished. 
         [0043]    As soon as the book block  18  is transferred to the despatch conveyor  5 , the speed of the clocking-in conveyor  3  is reduced until it once more reaches the first speed v 1 . The clocking-in conveyor  3  is thus in a position to take over the next book block  18  from the buffer conveyor  2 . 
         [0044]    For the second exemplary embodiment, the book block  18  is moved forward and transferred to the despatch conveyor  5  by the transfer conveyor  4 , which is arranged between the clocking-in conveyor  3  and the despatch conveyor  5 , is operated with a variable speed v 3  and is approximately synchronized with the clocking-in conveyor  3 . 
         [0045]    The transfer conveyor  4  can be used either as a simple transfer conveyor or as a correction belt. If the transfer conveyor  4  is used as a correction belt, an additional sensor, that may be embodied in detecting device  30  as previously mentioned, detects the position of the book block  18  on the transfer conveyor  4 , and the control unit  22  then corrects the deviation of the actual position of the book block  18  from its desired position via the drive  13 . 
         [0046]    With the apparatus  8 , a maximum possible processing speed can be computed for each book block  18  from the product parameters and the apparatus parameters. The product parameter “maximum permissible acceleration without change in the orientation of the sheets and/or the individual pages of the book block” is an important parameter. Together with the product data, this parameter can be supplied to the control unit  22  via the database  22   a  or can be entered manually into the control unit  22 . 
         [0047]    One method for determining these product parameters can be realized as follows: The control unit  22  starts up the apparatus  8  with a low acceleration value. During the course of the production, the control unit  22  automatically increases the acceleration value and the device  30 , which is may be arranged above the transfer conveyor  4 , monitors the orientation of the sheets and/or the individual pages of the book block  18 . If a change is detected in the orientation of the sheets and/or the individual pages of the book block  18 , this information is used to define the maximum permissible acceleration value for the order involving the corresponding book blocks  18 . 
         [0048]    According to a different variant of the first as well as the second exemplary embodiment, air or a different gas, supplied by the gas reservoir  32 , can be blown with the additional nozzle configuration  31  onto the book block  18  that is transported on the clocking-in conveyor  3 . The gas reservoir  32  can be connected to the control unit  22 . In case of production interruptions, the supply of gas can thus be stopped by the control unit  22 . In addition, the control unit  22  makes possible a precise metering of the amount of gas streaming out. As a result of the gas streaming out of several nozzle holes of the nozzle configuration  31 , the sheets and/or the individual pages of the book block  18  are admitted with an additional force that acts like a weight force. This additional weight force increases the force required to displace, relative to each other, the sheets and/or the individual pages of the book block  18 . The clocking-in conveyor  3  can consequently be subjected to higher accelerations, without causing a change in the orientation of the sheets and/or the individual pages of the book block  18 , transported thereon. 
         [0049]    The apparatus  8  as described in the above can also be used for orders where the format of the book block  18  changes from book to book. For this, the read-out unit  23  detects the identification marks on each book block  18 . The format of the book block  18  in conveying direction F, which is required for the following activation of the apparatus  8 , is then read out of the identification mark (RFID, bar code, and the like), or is read out of a database and is used to determine the adjustment variables for the apparatus  8 . The device  30  can also be used for this, wherein this device can detect the position and/or the format of the book block  18 , in particular its dimensions in conveying direction F, and can transmit these values to the control unit  22 . By correspondingly changing the speed v 1  of the buffer conveyor  2 , the feeding of the book blocks  18  to a clocked despatch conveyor  5  can thus be realized without having to generate empty cycles. 
         [0050]    It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.