Abstract:
An apparatus for collecting, stitching and/or cutting printed products includes an endless collector chain and feeders arranged one behind the other and above the collector chain for placing the printed products on the collector chain, and a stitching device for stitching or stapling the printed products, as well as a delivery unit for removing the printed products at the conveying end of the collector chain and for supplying the printed products to further processing. The apparatus also includes a drive unit which includes at least one servo drive which is controlled by a drive connected to the collector chain through a signal line in a timed synchronous manner and which drives additional units of the apparatus.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an apparatus for collecting, stitching and/or cutting printed products. The apparatus includes an endless collector chain and feeders arranged one behind the other and above the collector chain for placing the printed products on the collector chain, and a stitching device for stitching or stapling the printed products, as well as a delivery unit for removing the printed products at the conveying end of the collector chain and for supplying the printed products to further processing. The apparatus also includes a drive unit. 
   2. Description of the Related Art 
   Apparatus of the above-described kind have been known for a long time and have the purpose of collecting printed products and subsequently supplying them to another processing station. A stitching machine for stitching the collected printed products is usually arranged following the feeders. Such stitching machines and also suitable feeders are known in the art. The collector chain is constructed in the area of the feeders as a simple chain and has in regular intervals carrier members which protrude upwardly or laterally and on which the printed products placed on the collector chain are transported. The collector chain is constructed as a double chain in the area of the stitching machine and facilitates stitching of the collected printed products which rest astride on the collector chain. Prior to stitching, the printed products are frequently provided with addresses, for example, with a so-called ink jet device. Suitable for lifting the collected, stitched and addressed printed products is, for example, a conventional delivery unit which, for example, conveys the printed products to a trimmer which cuts the printed products. 
   A shiftable change gear unit is provided for driving the collector chain in the conventional apparatus (Harris saddle stitcher). This change gear unit makes it possible to adapt the chain speed to a collected chain with 21 or 14 inch divisions. 
   Alternatively, a drive of the collector chain is known in the art in a Müller Martini saddle stitcher (Prima) with a superimposed gear unit which facilitates timing or synchronizing of the collector chain during travel. The stitching mechanism and the stitching carriage of a stitching machine are additionally driven through a crank drive and an angular gear unit. 
   For achieving a clean and distortion-free addressing of the printed products with the above-mentioned ink jet device, an oscillation-free travel of the collector chain is important. At certain speeds, the feeders or the translatory movements of the stitching carriage and the trimmer produce oscillations which are transmitted to the collector chain and finally to the printed products. Such oscillations lead to distortions of the printed addresses. For preventing such oscillations, U.S. Pat. No. 4,384,709 proposes to additionally tension and drive the collector chain in the tensioning station and to provide the shaft which is connected to the main drive with a centrifugal mass. This type of oscillation damping produces relatively poor results considering the expenditures and must be adapted to the respective machine configuration. 
   SUMMARY OF THE INVENTION 
   Therefore, it is the primary object of the present invention to provide a way for avoiding vibrations at the collector chain, and to provide optimum prerequisites for addressing the printed products. 
   In accordance with the present invention, the drive unit includes at least one servo drive which is controlled by a drive connected to the collector chain through a signal line in a timed synchronous manner and which drives additional units of the apparatus. 
   The configuration according to the present invention provides the following significant advantages:
         vibrations of the stitching machine and of the trimmer cannot be transmitted to the collector chain;   the basic adjustment of the collector chain position relative to the delivery unit can be computed automatically and can be adjusted precisely;   the position of the collector chain relative to the delivery unit can be corrected during operation.       

   If, in accordance with a further development of the invention, each feeder is also driven by a servo drive, the following additional advantages are provided:
         the collector chain and the feeders can be operated independently of the remaining parts of the apparatus;   the superimposed gear units which were necessary in the past can be omitted;   the timing of the feeders relative to the collector chain can be computed in accordance with the size of the printed products;   an adjustment of the timing is possible during operation; and   a timing position which is displaced as the result of a problem can be automatically eliminated.       

   The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     In the drawing: 
       FIG. 1  is a kinematic drive diagram of a first embodiment of the apparatus according to the present invention; and 
       FIG. 2  is a kinematic drive diagram of a second embodiment of the apparatus according to the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The apparatus illustrated in  FIG. 1  includes a conventional collector chain  1 . The collector chain  1  is composed of a single collector chain  2  and a double collector chain  3  which are connected to each other through a transfer element  4 . The conveying direction is indicated by arrows  15  and takes place from the right to left as seen in  FIG. 1 . The single collector chain  2  is guided at a distance from the transfer element  4  about two guide wheels  6  and is tensioned between the guide wheels  6  by a tensioning station  5 . In accordance with a chain division of, for example, 14 or 21 inches, carrier members  7  are arranged in regular intervals A on the collector chain  2 , wherein, however, not all carrier members  7  are shown in the drawing. These carrier members  7  are mounted so as to protrude towards the top or side and to convey the printed products  8  in the direction of the arrows  15  towards the double collector chain  3 . This double collector chain  3  is also provided with carrier members, not shown. 
   The double collector chain  3  is provided at its front end with a drive wheel  18  which is driven by a drive  19 , i.e., a servo drive. This drive  19  is composed of an electric motor M 2  and a control unit  30 . The movement of the double collector chain  3  is transmitted by means of the transfer element  4  to the single collector chain  2 . 
   The folded printed products  8  are pulled by means of two successively arranged feeders  38  and  39  from a stack, not shown, and are placed on the single collector chain  2 . The feeders  38  and  39  have conventional opening drums, not shown, which open the printed products  8  in such a way that they are placed astride onto the single conveyor chain  2 , as seen in the drawing. Of course, the feeders  38  and  39  operate synchronously relative to the collector chain  2 . It is also possible to arrange more than two feeders one behind the other. 
   The two feeders  38  and  39  each have a superimposed gear unit  40  which is connected with a drive member  37  to a principal shaft  51  of a principal drive  22 . The timing of the feeders  38  and  39  relative to the collector chain  2  can be adjusted by means of the superimposed gear units  40 . Superimposed gear units  40  of this type are known in the art. 
   Following the feeders  38  and  39  in the conveying direction, a thickness measuring device  9  is provided for measuring the thickness of the collected printed products  8 . The thickness measuring device  9  is also driven by the principal drive shaft  51 . Arranged following the thickness measuring device  9  in the conveying direction  15  is an addressing unit  10 , particularly an ink jet addressing unit, which places addresses on the printed products  8 . This placement of addresses is possible during operation, i.e. without stopping the printed products  8 . 
   Incomplete products  81 ″ can be lifted from the single collector chain  2  by means of air nozzles  11 . 
   As mentioned above, the double collector chain  3  makes it possible to carry out stitching of the collected printed products  8 . For this purpose, a conventional stitching machine  12  is provided which includes a stitching carriage  14  and, for example, two stitching heads  13 . The stitching heads are actuated by a stitching mechanism  42  which is actuated by the principal shaft  51 . The stitching carriage  14  carries out a stroke in such a way that the printed products  8  can be stitched during travel. For carrying out this stroke, the stitching carriage is connected to a crank rod  52  which is hinged to a drive wheel  42  of a principal drive  22 . The rotary movement of the drive wheel  43  is transmitted through an angular gear unit  29  to the principal drive shaft  51 . The principal drive  22  is provided with a servo motor M 1  which includes a control unit  50 , and a drive member  24 . It is additionally possible to drive, through a shaft  25  and an angular gear unit  27 , particularly a trimmer  26  for cutting the printed products as well as an inserting machine, not shown. The control unit  50  of the servo drive  22  is connected through an electrical signal line  20  with control unit  30  of the drive  19 . The control unit  30  and the control unit  50  are configured in such a way that the drive  19  forms the so-called master and the servo motor M 1  forms the so-called slave. The drive  19  provides the servo drive  22  with control commands. The servo drive  22  follows the drive  19  synchronously with respect to rotation. 
   Consequently, the collector chain  1  can travel more uniformly and evenly because the servo drive  22  suppresses the vibrations produced by the stitching apparatus and the trimmer and other units, on the one hand, and the drive  19  of the collector chain  1  is mechanically uncoupled, on the other hand, while a certain non-uniform travel is acceptable for other units. As a result, vibrations of the feeders  38 ,  39  of the stitching unit and of the trimmer  29  cannot be transmitted to the collector chain  1 . If the drive  19  is a servo drive, it additionally facilitates an infinitely variable and precise adjustment of the position of the collector chain  1  during operation. The control unit  30  of the servo drive  19  makes possible an electronic change of the carrier member division from 21 to 14 inches or vice versa. This makes possible an automatic adjustment of the position of the collector chain  1 , for example, as a function of the size of the printed products  8 . It is also important in this connection that after a stoppage the servo drive  19  makes it possible to start up the collector chain  1  with the printed products in the exact position. An overload function is preferably integrated in the servo drive  19 . It is also important that the servo drive  19  makes it possible to independently adjust the division of the carrier members on the collector chain  1  relative to the remaining units of the apparatus. 
   The stitched printed products  8 ′ are grasped by means of gripping members  17  of the conventional delivery units  16  and are supplied to the trimmer  26  where the printed products  8 ′ are usually cut at three sides. The position of the collector chain  1  relative to this delivery unit  16  is essential and the servo drive  19  makes it possible to correct this position during operation. 
   The embodiment of  FIG. 2  differs from that of  FIG. 1  in that feeders  33  and  34  are provided which are not driven by the principal drive shaft  51 , but are each driven by a separate servo drive  35  and  36 , respectively. These servo drives  35  and  36  each have an electric motor M 3  and M 4 , respectively, and a control unit  31  and  32 , respectively. The rotary movement is transmitted to the feeders  33  and  34  through drive members  37 . The feeders  33  and  34  otherwise correspond to the feeders  38  and  39  of  FIG. 1 . The servo drives  35  and  36  are connected through signal lines  21  to the servo drive  19  and the control unit  30 . The servo drive  19  forms the master and the servo drives  35  and  36  form the slaves. Consequently, the servo drives  35  and  36  follow the servo drive  19 . An overload function is also preferably integrated in the servo drives  35  and  36 . The servo drives  35 ,  36  can be secured against overload by an adjustable current limitation. It is also important that the superimposed gear units  40  provided in the embodiment of  FIG. 1  are not required in the embodiment of  FIG. 2 . In the embodiment of  FIG. 2 , the operation of the superimposed gear units can be carried out electronically through the control units  31  and  32 . 
   Of course, it is possible to use the apparatus according to the present invention for processing in accordance with the 2:1 operation. A 2:1 operation is carried out when two feeders are in operation with the same sheets alternatingly with half speed. 
   The timing position of the feeders  33  and  34  relative to the collector chain  1  can be stored in the control units  31  and  32 . After a stoppage which causes the position to be lost, the control units  31  and  32  can automatically find the stored position. When selective binding is carried out, the feeders  33  and  34  can be easily switched on and off in a controlled manner during operation of the apparatus; this means that the feeders are treated gently. 
   Since the feeders  33  and  34  are not mechanically connected to the principal drive shaft  51 , the feeders can be mounted, for example, so as to be foldable upwardly, which makes it possible, for example, to make room for a card applicator. 
   It is also much more simple than in the past to adjust the height of the feeders  33  and  34  relative to the collector chain  1 . 
   The trimmer  26  mentioned above can be driven by a separate servo motor, not shown. This makes it possible to separately operate the trimmer  26 . 
   The servo drive technology according to the present invention will make it possible, for example, to drop the electrostatically charged sheets at a higher speed onto the collector chain when the saddle stitcher is stopped or to hold back the sheets in the feeder, or, when the saddle stitcher is once again started up, to switch on the feeder only when a certain speed is reached. This makes it possible to more safely feed the electrostatically charged printed products to the collector chain. 
   The invention is not limited by the embodiments described above which are presented as examples only but can be modified in various ways within the scope of protection defined by the appended patent claims.