Patent Publication Number: US-7210887-B2

Title: Bookbinding machine

Description:
This application claims the benefit of German Patent Application No. DE 102 21 542.1, filed May 15, 2002. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a bookbinding machine and more specifically to a bookbinding machine in which the drives of workstations for performing positionally accurate operations on inner books are not mechanically coupled to the main drive for the book binding machine. 
     2. Description of the Related Art 
     A bookbinding machine to which the invention relates is described, for example, in DE 198 46 525 A1 and is also referred to as an adhesive binder having a clamp system. One inner book in each case is clamped by an inner-book clamp while standing on its spine and in this position is transported past various stations. In addition to stations for processing the inner-book spine, such as cutting-off, notching, roughing and brushing, stations are provided for applying adhesive to the spine and/or to the lateral faces close to the spine, for applying reinforcement or gauze sections and for applying jackets. In addition, there are stations for drying and contact pressing and stations for moving the products in and out. The equipment of an adhesive binder having the various stations depends on the products to be manufactured. It is, of course, limited by the available space, which is determined by the number of inner-book clamps. 
     The transport system with the inner-book clamps consists of a multiplicity of inner-book clamps that are movable via horizontal and vertical rollers in upper and lower guide rails forming a closed, continuous track in a frame. The inner-book clamps are articulated at equal mutual pitch distances from one another to a continuous roller chain driven in known fashion via a chainwheel. The chainwheel is in turn driven via a drive system consisting of a motor, transmission and angular gears and further drive shafts connecting the different components. As an example, a transport system with inner-book clamps is described in DE 24 58 543 C2. When being transferred to the inner-book clamp, the inner book to be clamped is aligned to a rear-edge stop of the inner-book clamp. 
     To carry out accurately-timed processing the stations designated for this purpose are connected by direct mechanical coupling via a main shaft to the drive system of the transport system of the inner-book clamps. The respective drive connections are adjusted in relation to the rear-edge stop of the inner-book clamps. In addition, functions are performed in adhesive binders which are driven pneumatically or electromechanically. Their actuation is controlled using the signals from a shaft encoder measurement system which is arranged in the drivetrain on the main shaft of the adhesive binder to capture the absolute rotary motion of said shaft. A theoretical position on the inner-book clamp is associated with the particular angular position of this shaft. 
     The exact positions of the individual inner-book clamps at a particular time are not, however, determined by this indirect measuring system. Oscillations of the drive system superimposed on the chain movement, unequally-stretched sections of the roller chain and play in the drive links are not allowed for in determining the position of the inner-book clamp. The processing functions dependent thereon are performed in a correspondingly inaccurate manner. Moreover, the case is similar with the mechanically coupled stations, since chain stretching or the actual distances in the chain pitches can only be accounted for in terms of all the inner-book clamps as mediated through the adjustment of the drive coupling; furthermore, in the case of spatially extensive drive connections synchronising inaccuracies as a result of play and oscillations are increased. In particular when applying jackets, however, exact coordination of the feed of a jacket with the transporting of the inner book allocated thereto is required. Known from DE 31 39 656 C2 is a jacket application station in which circulating alignment elements for the jackets move between two inner-book clamps and are resiliently braked and aligned by abutting against the rear edges of the inner-book clamps or of the inner books. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to create a bookbinding machine of the above-mentioned type which makes possible the performance of precise positioning operations in workstations while being of simple construction. 
     This object is achieved according to aspects of the present invention by abolishing the mechanical coupling of the drives of the workstations to the drive of the transport system of the inner-book clamps, and in driving the former and latter elements independently of one another. Another aspect of the invention relates to a measuring system being provided for detecting the position of the inner-book clamps or the inner books in the vicinity of a workstation for controlling the timing of workstation operations on the inner books. Adjacent workstations may be controlled as a function of the position detected from a single sensor. 
     The mechanically uncoupled workstations are driven by motors, or are driven hydraulically, pneumatically or electromechanically. The drive system is broken up into small partial systems less subject to oscillations. Operations performed by the workstations are carried out markedly more accurately because the position sensing is carried out locally. Electronic controls make adjustment of the machine simpler and more precise. Further, a bookbinding machine according to the invention simplifies the replacement or addition of workstations because the adjustment of the drive connections in relation to the rear edge of the transported inner books is dispensed with. An advantage of the bookbinding machine according to the invention is that work processes dependent on inner-book position, such as side-stitching, punching, gluing, reinforcing, jacket application, etc., take a substantially simpler form. This advantage is characterised, among other benefits, by a smaller installation space requirement. 
     A preferred embodiment of the inventive bookbinding machine is provided when all workstations, previously coupled mechanically, are driven independently of the drive of the transport system of the inner-book clamps. The main shaft can thereby be dispensed with. But even partial mechanical uncoupling offers advantages if, for example, workstations are to be used in bookbinding machines which are differently configured with respect to the central drive system. 
     The bookbinding machine may be provided with a monitoring station for carrying out optical quality control procedures with respect to the operations performed, this monitoring station being controlled as a function of the detected exact position of the inner-book clamps or of the inner books. 
     A position control system which coordinates the independent drives with one another during operation and/or after interruptions of operation is expediently associated with the individual drives. Different control systems can be used. The workstations arranged in the vicinity of the deflector wheel of the traction means of the transport system are advantageously controlled by the position signals of a shaft encoder measurement system fitted to this wheel. Very precise detection of the position of the inner-book clamps in this area is thereby provided. The position detection is preferably effected by means of a linear distance measuring system. The use of a plurality of sensing heads located in the area of a workstation is expedient here. The different operations are thereby carried out substantially more accurately. An aspect of the invention relates to a bookbinding machine that automatically adapts itself to changing conditions in the transport system of the inner-book clamps. 
     The mechanically uncoupled workstations are advantageously designed to be compatible with the timing distances in different bookbinding machines (also referred to as adhesive binders). When used in a bookbinding machine having a given timing (pitch) distance (T) between the inner-book clamps, the workstations are adjustable to this timing distance. The construction of variants with respect to timing distances is rendered superfluous. In addition, the production, storage and preparation for service of these workstations are greatly simplified. It is also advantageous that the workstations are electronically adjustable with respect to the positions or format height of the inner books. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be elucidated in more detail with reference to an embodiment illustrated in the drawings, in which: 
         FIG. 1  is a simplified top view of a bookbinding machine including schematic representations of drive and control components and interconnections; and 
         FIG. 2  is an enlarged reverse perspective view of an inner-book clamp appropriate for use in conjunction with the bookbinding machine of  FIG. 1 , the inner book clamp is shown in functional conjunction with an upper and lower guide rail and roller chain (both broken away), a sensor and bracket are also shown. 
     
    
    
     DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT 
     An exemplary embodiment of a bookbinding machine  1  consists of a transport system  5  having a multiplicity of continuously movable inner-book clamps  6  articulated to a continuous roller chain  7  circulating in a closed track, spine-processing stations  30   a–d  and workstations  32 ,  35 ,  37 ,  40 ,  43  and  46  for carrying out positionally precise processing operations. Inner books  2  collated as loose sheets are bound in the bookbinding machine  1  and, in a processing variant, are finished as brochures  4  by the application of a jacket  3 . The inner books  2  enter the bookbinding machine  1  while standing on their spines via an intake  24 . They are transferred, while being aligned to a rear-edge stop  12 , to the inner-book clamps  6  which, starting from an open position  6   a , clamp the particular inner book  2  by its lateral faces with an inner jaw  10  and an outer jaw  11  closing relatively thereto. A given portion of the inner book projects downwardly from the inner-book clamp  6  for processing. 
     The inner-book clamps  6  are supported during movement in the transport direction F by means of horizontal and vertical rollers  13  and  14  in upper and lower guide rails  15   a ,  15   b . The upper and lower guide rails  15   a ,  15   b  form a closed continuous track. The inner-book clamps  6  are articulated at equal mutual pitch distances T to the roller chain  7  by means of axle pins  16 . The roller chain  7  is driven via a drive chainwheel  8  and a deflector chainwheel  9  to form an oval continuous track. The drive chainwheel  8  is connected in turn via a transmission  23  to a drive  22  formed by a motor  22   a  and a control unit  22   b . The drive  22  is monitored and controlled by a central position control unit  20  communicating with local control units via signal lines  21 . The exact position of said drive  22  is transmitted to the position control unit  20  via a resolver feedback  55 . The intake mechanism  24  and an output mechanism  25  which removes the brochure  4  from the opening inner-book clamp  6 , 6   a , are driven with direct mechanical coupling  26  by the drive  22 , the drive connection  26  including transmissions  27 ,  28 . In the embodiment described here the coupling of further stations to the drive  22  is not provided. The drive system thereby has a compact and mechanically simple configuration. 
     The different stations are arranged along rectilinear sections of the transport system  5 , the spine processing stations  30   a–d  first processing the spine of the inner book in the sequence: cutting-off, notching, roughing and brushing. The stations  30   a–d  are driven by drives  31  in each case. Processing is not effected in relation to timing or position. The drives  31  are therefore merely switched on and off by the central control unit  20 . 
     The processing of the spine is followed by gluing of the spine and the adjacent lateral areas. In the present embodiment two spine gluing stations  32   a ,  32   b  are provided which remove the glue from a glue store with rotationally-driven gluing rollers and transfer it to the spine, the application thickness being adjustable by a scraper plate, which may also be referred to as a “doctor blade”. The position of the scraper is controllable between a zero position and a glue position. In the zero position the scraper reduces the height of glue on the roller to zero by scraping the glue off the roller. In the glue position, the scraper is spaced from the roller such that glue remains on the roller to be applied to the inner book. The scrapers are pneumatically or electromechanically controllable so that the glue is applied with positional accuracy to the inner book. The gluing rollers are connected to a drive  34  which is composed of a frequency-controlled (servo) motor  34   a  and a control unit  34   b  and is controlled by an overriding control unit  33 . The control unit  33  also controls the pneumatically or electromechanically driven scrapers, the resolver feedback  55  being taken into account via the position control unit  20 . A side-gluing station  37  which applies the glue with application heads  39  and associated nozzles is provided for gluing the lateral areas close to the spine. A control unit  38  activates the associated valves of the application heads  39 , the signals of a position detection arrangement located directly ahead of the application heads being taken into account. 
     The position detection arrangement is a linear distance measuring system having material measures  17  attached to the inner-book clamps  6 , with a measuring strip  18  protected by a covering strip  17   a  and having a periodic measuring position and with fixed sensing heads  52 ,  52   a–c  on holders  53 . As the inner-book clamps  6  are moved the sensing heads  52  supply with the signal line  54  incremental signals together with a distance-coded reference signal which is tapped by a reference track  18   a  located parallel to the measuring position and determines the absolute position of the inner-book clamp  6  concerned. For the side-gluing station  37  the exact position of the inner-book clamp is detected with the sensing head  52   b . From this position the control unit  38  determines the times for triggering and ending the application process according to the predefined position while taking account of the actual running speed of the bookbinding machine  1 , the delay times of the different actuators and further influence values. 
     A side-stitching station  35  which drives wire stitches through or into the inner books  2  from the side in the area adjacent to the spine with pneumatically driven stitching heads is arranged ahead of the side-gluing operation. Its operation is comparable to that of the side-gluing station  37 . For this operation the associated control unit  36  receives position signals from the sensing head  52   a . By means of optional monitoring of the glue applications and/or the stitching by a monitoring station of the same kind as the monitoring station  49  described below, positions are checked and deviations from the reference positions are detected, among other checks. The fundamental delay times of the different stations  32   a ,  32   b ,  35  and  37  due to their actuators are correspondingly changed in the associated control units  33 ,  36  and  38 . An adaptive adjustment to changing conditions takes place. 
     The stations  40 ,  43  and  46  which now follow are arranged in the area of the deflector chainwheel  9 . The positions of the inner-book clamps  6  in this area can be determined with considerable accuracy from the absolute angular position of this wheel, for which reason a measuring system with a shaft encoder  51  is provided in that location. The position control unit  20  has access to the position signals generated at this location and sends control signals relating thereto to the stations arranged in that area. These are, specifically, the reinforcement station  40 , the jacket application station  43  and the contact pressing station  46 . Associated with each of these stations is a respective drive  42 ,  45  and  48  composed of a respective servo motor  42   a ,  45   a  and  48   a  and a respective servo control unit  42   b ,  45   b  and  48   b . Overriding each of these drives are further respective control units  41 ,  44  and  47  which communicate with the position control unit  20  and control functions in the stations  40 ,  43  and  46  which are not dependent on the drives of these stations or controlled thereby. Through the position detection effected close to the stations positioning operations to be carried out in the stations, i.e. the application of the reinforcing strip, the application of the jacket and pressing of the jacket against the spine are carried out considerably more accurately than if position detection were taken account of by the resolver feedback  55 . 
     A monitoring station  49  for performing optical quality control procedures is provided after the contact pressing station  46 . For example, the position of the jacket  3  on the inner book  2  is checked. For this purpose it is important to coordinate the corresponding signal of a light barrier with a very specific position of the inner-book clamp  6 . The exact position of the inner-book clamp  6  is determined using the linear distance measuring system and specifically by the sensing head  52   c  arranged in the monitoring station. As described above, a monitoring station which carries out a quality control operation by image processing is optionally provided after the gluing operation. The image of the glued spine of the inner book to be assessed by the quality control system must be acquired at a specific position of the inner-book clamp  6  which is determined using the linear distance measuring system. 
     While a preferred embodiment of the foregoing invention has been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and the scope of the present invention.