Abstract:
An apparatus for manufacturing book covers having a board feed for supplying cover boards and a spine insert having a covering material feed for supplying covering material, having a covering material cylinder, by means of which the supplied covering material is taken over, conveyed past a glue spreading roller and assembled with the supplied cover boards and having a folding and pressing apparatus as well as having a delivery apparatus and having a drive apparatus for the covering material feed, the board feed the covering material cylinder and the folding and pressing apparatus it is provided that at least the covering material feed the board feed and the folding and pressing apparatus are drivable in each case independently of one another. The covering material cylinder is preferably also provided with an independent drive. The independent drives are preferably servomotors, which are designed in each case as a slave and follow a virtual master The essential advantages of said apparatus are product-protecting and efficient fault handling as well as simple setting-up and correction operations.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to an apparatus for manufacturing book covers. 
   Apparatuses of said type are known as book cover machines based on a horizontal processing principle, in which in a continuous pass cover boards and a spine insert are combined in a correctly fitting manner with the glue-coated covering material in a roll-on device. In successive work stations the projecting edges of the cover, either while in motion or while stationary, are folded, generally first at the edges projecting from the top and bottom and then, after drawing-in of the corners, at the sides. The book covers are then conveyed between press rollers of a pressing apparatus, in which separate systems rub the board covers and the spine insert onto the covering material. In a delivery station the book covers pass in the form of stacks over a roller table for manual removal. 
   The cover boards are stocked on a prestacking belt, from which they pass in streams or in stacks into a board feed hopper. The lowermost cover boards are pushed out of the feed hopper and supplied together with the spine insert on guide rails in a laterally aligned manner to the rolling-on device. As a spine insert, flexible roll screening cut to length and width in the machine or a cardboard strip previously cut to size may be used, which is introduced into the feed plane of the cover boards immediately prior to the rolling-on operation. In synchronism with the board feed, the covering material is brought by a covering material cylinder into the rolling-on plane. The covering material is decollated from a covering material feed hopper, optionally aligned and supplied by further conveying devices to the covering material cylinder, which takes over the covering material with grippers and conveys it past a glue spreading roller prior to the rolling-on operation. 
   In the previously known apparatuses the essential functions, such as the board feed, covering material feed, covering material cylinder and folding and pressing apparatus, are coupled directly to one another by a common drive. The functions of decollating the covering material and decollating the cover boards are switchable on and off. Feeding of the spine insert processed from the screening roll is effected by an individual drive controlled in a clocked manner. Further individual drives are assigned to peripheral functions, such as restocking the board feed hopper, stacking and delivering the finished book covers etc. As a result of the direct coupling of the drives of the main functions the entire book cover machine is stopped as soon as a fault arises in the region of the board feed or the covering material feed, and the book cover machine is not re-started until after the fault has been eliminated. Because of the long waiting period, book covers which are situated during said period in the folding apparatus are not durably glued together and have to be discarded as rejects. The result is a lower effective output. 
   In the known book cover machines the book covers are joined and moved forward in such a way that the leading edges of the boards and book covers are oriented by fixed reference edges, which is also known as conveying with a constant leading edge. The board feed pushes the cover boards and the spine insert towards the rolling-on device by acting on their trailing edge. The stroke position of said board pusher therefore has to be adapted to the book cover format by suitable adjustments, with the result that the board feed is complex and there is only a limited possibility of carrying out a necessary correction during operation. The folding width at the top and bottom of the cover is dependent upon the length difference between the covering material height and the cover board height and/or in some cases also upon the printing format of the covering material. Setting-up of the folding width as well as correction during operation are effected by means of an elaborate differential drive, which is connected in the drive train upstream of the covering material cylinder and the covering material feed and by means of which the covering material is supplied by its leading edge at an earlier and/or later time to the rolling-on device. The setting-up of a new book cover format is time-consuming and therefore reduces the effective output of the machine. 
   SUMMARY OF THE INVENTION 
   The object of the invention is to improve an apparatus for manufacturing book covers of the described type in such a way that the effective output of the apparatus is substantially improved. 
   The object is achieved in a surprisingly simple and economical manner in the subject apparatus, where at least the covering material feed, the board feed and the folding and pressing apparatus are drivable in each case independently of one another. 
   In the event of a fault in the board feed or in the covering material feed, only the further feed of boards and covering material is stopped, while assembled book covers are completed in the folding and pressing apparatus and fed to the delivery apparatus. Said book covers are securely glued together and need not be discarded as rejects. If the fault e.g. in the board feed has been eliminated by removing the boards of one or more cycles, it is possible by discontinuing the feed of covering material to defer the cycle of the covering material feed automatically by one or more cycles. Secondary faults as a result of feeding covering material without associated boards are avoided. The servo drives may be operated with an adjustable driving torque, with the result that overload functions may be realized in the drive apparatus. 
   The cycle of the covering material feed and the covering material cylinder relative to the folding and pressing apparatus may be automatically calculated on the basis of the format of the book covers to be manufactured and the covering material height and started. Equally, the stroke position of the board feed, by means of which the boards are pushed at their trailing edge and delivered by their leading edge in clocked synchronism, relative to the joining point of the book covers may be calculated on the basis of the board height and automatically approached by means of the servo drive when the maximum stroke of the board pusher comprises the actual working stroke and the adjustment travel. Previously required differential drives and/or adjusting means may be omitted. A correction of the format adjustments and hence a correction of the position of the assembled book cover elements is possible during operation. The covering material feed may be set up and operated independently of the other devices of the machine. 
   Traction means such as toothed belts or chains, for reasons to do with their manufacture, do not have a precise pitch. When covering material is fed forward by such means over a plurality of cycles, the individual pieces of covering material are supplied with a varying leading edge to the covering material cylinder. By virtue of the covering material cylinder, which is controlled by an individual servo drive and at times rotates forwards and/or backwards relative to the angle of the folding and pressing apparatus, the covering material is taken over in accordance with the detected leading edge from the covering material feed and at a later stage of transport is conveyed in such a controlled manner that the covering material is rolled with the exact leading edge position onto the boards. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     There now follows a detailed description of an embodiment of the invention, which is illustrated in the drawings. The drawings show: 
       FIG. 1  is a kinematic drive diagram of a book cover machine with functional units illustrated in a simplified side view, and 
       FIG. 2  is an enlarged detail of the book cover machine. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The drawings show in a diagrammatically simplified view a book cover machine  1 , in which book covers  5  are manufactured by combining glue-coated covering material  2  with cover boards  3  and spine inserts  4 . The covering material  2  is transferred by a covering material feed  10  to a continuously rotating covering material cylinder  20 , by means of which the covering material  2  is taken over by grippers  21 , conveyed past a glue spreading roller  22  of a gluing mechanism  23  and released at the rolling-on point  6 . Synchronously with the respective piece of covering material  2  a left and a right cover board  3  as well as a spine insert  4  are supplied by a board feed  30  to the rolling-on point  6 . At the rolling-on point  6  pressure rollers  24 , which act separately upon the cover boards  3  and the spine insert  4 , ensure that the covering material  2  is rolled in a bubble-free manner onto the boards  3 ,  4 . 
   The covering material feed  10  comprises an, as such, known covering material feed hopper  11 , by means of which in each case the lowermost piece of covering material  2  is separated from a stack, pushed out in a forward direction and supplied to take-off rollers  12 , by means of which the covering material  2  under the stack is drawn away and transferred to a likewise known aligning apparatus  13 . The covering material  2 , which is aligned at the leading edge and at one side in the stationary state in the aligning apparatus  13 , is accelerated by acceleration rollers  14  up to the continuous conveying speed of a covering material conveying apparatus  16 , which conveys the covering material  2  for a plurality of cycles, and then transferred to said apparatus. A light barrier  15  detects the arrival and departure of the covering material  2  in the aligning apparatus  13 . The covering material conveying apparatus  16  comprises a plurality of conveyor belt pairs  17  placed at a distance from one another, wherein a top toothed belt  17   a  presses the covering material  2  onto an elastic support (not shown here) of a bottom toothed belt  17   b . Disposed at the end of the conveying path is a light barrier  18 , which detects the position of the covering material leading edge and supplies the detected position to a control device, which is described later. 
   Associated with the board feed  30  is a prestacking belt  31 , which is provided with a separate drive  91  and which receives the cover boards  3  in an almost upright position and feeds them in a stream to a board feed hopper  32  in that the drive  91  is operated by means of a central control unit  99 , which converts the corresponding signals of a light barrier  33 . The board feed hopper  32  has a format-defined reference edge  32   a , against which the cover boards  3  are applied by their leading edge. For different format heights the prestacking belt  31  is positioned accordingly. 
   The cover boards  3  are pushed by a first board pusher  34   a  out of the board feed hopper  32  and transferred with a constant stroke into an intermediate position  36  with a format-defined reference edge  36   a . In said intermediate position  36  there is inserted between the two cover boards  3  a spine insert  4  in the form of flexible endless screenings, a suitable length of which is withdrawn from a screening roll  38  by a take-off roller system  37 . Via a guide  40  in the form of a flap the spine insert  4  passes into the conveying plane of the cover boards  3  and is cut to length by a cutting device  39 . The take-off roller system  37  is operated by a drive  92 , which is provided with a stepping motor and with which a control device  93  is associated, which ensures that the required length of the spine insert  4  is withdrawn in clocked synchronism from the screenings roll  38 . The time window, within which the withdrawal has to be effected during a work cycle, is communicated to the control device  93  by the central control unit  99  via electric signal lines  98 . 
   The cover boards  3  and the spine insert  4  are then pushed by a second board pusher  34   b , which executes the same stroke as the first board pusher  34   a , to the rolling-on point  6  and in the process are aligned in an outward direction in corresponding feed edges. The board pushers  34   a,b  are fastened to a toothed belt  35 , the maximum stroke of which comprises both the constant working stroke and the adjustment travel required for the different board heights. For other board formats, through relative rotation of the toothed belt drive only the stroke position is displaced, and the board pusher unit as a whole need not be adjusted. Light barriers  41   a, b, c  detect the pushing-in and pushing-out of the boards  3 ,  4  in the intermediate position  36 , a further light barrier  42  monitors the conveying of the spine insert  4 . 
   At the rolling-on point  6  the boards  3 ,  4 , which are pushed forward at a speed synchronous with the covering material  2 , are rolled by the pressure rollers  24  onto the glue-coated covering material  2  and, while still being pushed forward by the second board pusher  34   b , are grasped by a reciprocating suction crosspiece  51 , which is controlled via a toothed belt  52  and moved forward likewise in synchronism during the rolling-on operation, of the folding and pressing apparatus  50  and conveyed with a stroke, which is constant  30  for each format, into a top/bottom folding station  53  with a format-defined reference edge  53   a , up to which the leading edge of the book cover  5  is conveyed. 
   In the top/bottom folding station  53  the book cover  5  in a first step is taken over by suction press rams  54   a, b  and pressed by the latter onto folding tables  57   a, b  of a lower-lying top/bottom folding position  55 , wherein the projecting edges of the covering material  2  in the course of the transfer motion right themselves against righting edges  56   a, b . In a second step the righted edges are folded by folders  58   a, b  round the board edges and pressed firmly onto the insides of the boards. During said process, the corners are drawn in by means which are not shown here. In the last step the book cover is grasped by a jamming roller  59  and a jamming pad  60  and, after the folders  58   a, b  and the folding tables  57   a, b  have been retracted, deposited onto a conveyor belt  61  below the top/bottom folding position  55 . Said jamming roller presses the book cover  5  onto the conveyor belt  61 , while the jamming pad  60  releases the book cover  5 . With a stroke, which is constant for all formats, the book cover  5  is then conveyed from the top/bottom folding station  53  into a side folding station  64 , wherein pressure rollers  63  disposed along the conveying path press the book cover  5  onto the conveyor belt  61 . A light barrier  62  monitors the arrival and transfer of book covers  5  in the upper position of the top/bottom folding station  53 . 
   On its way into the side folding station  64  the book cover  5  runs with its sides over folding tables  65 , which are situated to the left and right of the conveyor belt  61  and which right the edges of the covering material  2  which are still projecting from the sides of the book cover  5 . Having arrived in the side folding station, the book cover  5  is first fixed on the folding tables  65  by holding-down devices, which are not shown here. The righted edges are then folded by folders  66  round the side board edges and pressed firmly onto the insides of the boards. Once the folders  66  and the holding-down devices have released the book cover  5 , the conveyor belt  61  feeds the completely folded book cover  5  to a pressing station  68 , in which pressure rollers  69  firmly apply the cover boards  3  and pressure rollers  70  adapted to the width of the spine insert  4  firmly apply the spine insert  4  of the book cover  5 . A light barrier  62  monitors the inward and outward conveying of the book covers  5  in the side folding station  64 . 
   In the delivery apparatus  80  the finished book covers  5  are initially placed one on top of the other in partial stacks in an upper stacking plane  81  and deposited through suitable operation of stacking rakes  82  onto the actual book cover stack  83 , which on reaching the desired stack quantity is transferred by a delivery belt  84  transversely out of the book cover machine  1  onto suitable storage conveyors, from which removal may be effected by hand or by palletizing robots. The delivery belt  84  is operated by a drive  94 , which is provided with a motor and is connected by the central control unit  99  for the outward conveying of book cover stacks  83 . 
   The book cover machine  1  is provided with a drive apparatus  100 , which substantially comprises four independent drives  110 ,  120 ,  130 ,  150 , which are respectively assigned to the functional units of covering material feed  10 , covering material cylinder  20 , board feed  30  and folding and pressing apparatus  50  and provided with servomotors  111 ,  121 ,  131 ,  151  and associated control devices  112 ,  122 ,  132 ,  152 . 
   Further uniform- and non-uniform-motion transmissions  113 ,  114 ,  115 ,  116  are associated with the drive  110  of the covering material feed  10 , wherein the transmission  113  shown in the drawings represents a plurality of transmissions, by means of which functions of the covering material feed hopper  11  are operated. Equally, the transmission  115  comprehends the transmissions needed to operate the functions in the aligning apparatus  13 . The drive  120  is directly connected to the covering material cylinder  20  and via a transmission  123  also drives the gluing mechanism  23 , which is additionally connected to a constantly driving auxiliary drive  124  and therefore rotates even when the drive  120  stops the covering material cylinder  20 . In the board feed the toothed belt  35 , which moves the board pushers  34   a, b  forwards and backwards, is driven by the drive  130 . In the aligning and pressing apparatus  50  the individual functions and/or stations are operated via transmissions  153 ,  154 ,  155 ,  156 , which are associated with the drive  150 . The transmission  154  symbolizes a group of transmissions, which are needed to operate the functions in the top/bottom folding station, while the transmission  156  comprehends the transmissions for the side folding station. 
   The control devices  112 ,  122 ,  132 ,  152  are connected to one another by a central servo-control  102  via electric signal lines  101  and are designed in such a way that the central servo-control  102  forms a so-called virtual master  102  and the servomotors  111 ,  121 ,  131 ,  151  form the so-called slaves. The virtual master  102  issues control commands and the drives  110 ,  120 ,  130 ,  150  follow in angular synchronism. By virtue of the subdivision of the drive apparatus  100  into the individual drives  110 ,  120 ,  130 ,  150  product-protecting fault handling is possible. Should a fault arise in the covering material feed  10  and be signalled e.g. by the light barrier  15 , the covering material feed  10  and the board feed  30  are stopped by the higher-level central control unit  99 , while the folding and pressing apparatus  50  and optionally the covering material cylinder  20  continue to be operated until all of the book covers  5  assembled at the time of the fault have left the pressing station  68 . The same applies in the event of faults in the board feed  30 , which are signalled by the light barriers  41   a, b, c  and  42 . 
   By virtue of the individual drives  110 ,  120 ,  130  format adjustments may be effected electronically. For other board heights, the stroke position of the board pushers  34   a, b  is automatically calculated upon entry of the format sizes into the central control unit  99  and adjusted through rotation of the drive  130 . The calculated folding width is set through rotation of the drives  110 ,  120 . The variables may moreover be corrected also while the book cover machine  1  is running. An overload function is preferably integrated in the servo drives  111 ,  121 ,  131 ,  151  in that the drives are protected by adjustable current limiting. 
   The individual servo drive  121  for the covering material cylinder  20  makes it possible for covering material  2 , which is supplied by the toothed belt  17   a, b  of the covering material conveying apparatus  16  to the covering material cylinder  20  with its leading edge out of step, to be taken over in accordance with the supplied position and rolled in the exact position onto the boards  3 ,  4  at the rolling-on point  6 . The supplied position is detected by the light barrier  18  and the drive  120 , prior to the take-over, rotates the covering material cylinder  20  in accordance with the calculated positional deviation forwards or backwards relative to the virtual master  102  in order to bring the covering material  2  after the take-over into the exact position by means of an accompanying counter movement.