Abstract:
An apparatus for trimming unbound side edges of a print product includes a plurality of trimming devices arranged at a distance to each other. A positioning device aligns the print product. A feeding device receives the print product from the positioning device and successively position the print product in a respective one of the trimming devices for a cut.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the priority of European Patent Application No. b  03405581 . 4 , filed on Aug. 7, 2003, the subject matter of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     The invention relates to an apparatus for trimming unbound side edges of print products such as books, brochures or magazines, the apparatus comprising at least one trimming device, one positioning device for aligning the print products, and one feeding device. Apparatuses of this type are known in the print-processing industry and are used for trimming the top, bottom, and front edges of print products, for example books, brochures and magazines. As a rule, a print product with rough format is trimmed, for example, to the Formats A4 to A6.  
         [0003]     European patent document EP 0 842 746 discloses a method and an apparatus for trimming unbound side edges of print products. With this method, the print products are gripped at the bound side edge by a positioning device and are supplied with a rotational and translational movement to a trimming device. The trimming device simultaneously trims two print products at the top and/or the bottom, wherein the two print products to be trimmed simultaneously must be of the same size. For that reason, this method is particularly suited for trimming large series of identical-size print products, but is less suited for use with small series, e.g. as produced with a digital printing process. In addition, the conversion to a print product having a different format is expensive and involved.  
         [0004]     European patent document EP 0 710 530 A also discloses an apparatus for trimming unbound side edges of print products. The print products to be trimmed are gripped by a product gripper, which can be moved with a rotational and translational movement relative to the trimming knife. However, a conversion to a different format is time consuming with this apparatus as well. The device is therefore also not suitable for small series which can be produced cost-effectively, in particular with a digital printing technique.  
       SUMMARY OF THE INVENTION  
       [0005]     Thus, it is an object of the present invention to create an apparatus that is suitable for trimming comparably small numbers of print products. In particular, the apparatus should be suitable for trimming book blocks and books, as well as bound and stitched brochures and magazines, and should also be suitable for trimming print products having different rough format sizes.  
         [0006]     The above and other objects are accomplished according to an exemplary embodiment of the invention in which an apparatus of the type first mentioned above is provided with several trimming devices, arranged at a distance to each other, and the feeding device is designed so that the print products to be trimmed can be positioned successively in each of the trimming devices for a cut.  
         [0007]     With the apparatus according to the invention, the print products are aligned in the positioning device and are then supplied to the feeding device. The feeding device successively feeds the print products to the trimming devices where they are respectively positioned and where respectively one side cut is made. By using a suitable control for the feeding device, the apparatus can be used to trim different rough formats without requiring involved conversion measures, wherein smaller print product series can be trimmed as well. Smaller series of this type are produced in particular with digital printers.  
         [0008]     The apparatus design can be particularly simple and economical if, according to one modification of the invention, the print products are aligned respectively along one (non-cut) side edge and the product back in the positioning device and are supplied by the feeding device to the trimming devices, without any change in this alignment. For this, the print products are preferably gripped along the back and/or a bound side edge. The sequence of steps is particularly advantageous if, according to another modification of the invention, the print products are essentially moved along a circular course by the feeding device, thus resulting in an apparatus that requires comparatively little space.  
         [0009]     According to yet another modification of the invention, the print products aligned in the positioning device are gripped by a product gripper and are moved with a predetermined linear displacement movement to a transfer position. The alignment of the print products during the trimming operation thus corresponds to the alignment in the positioning device. The transfer consequently requires only a predetermined, linear movement and/or a displacement.  
         [0010]     The apparatus according to the invention comprises a positioning device for aligning the print products to be trimmed, a feeding device, as well as several trimming devices that are arranged at a distance to each other. The feeding device is designed such that the print products to be trimmed can be positioned successively in each of the trimming devices for a cut.  
         [0011]     A particularly advantageous embodiment is obtained if, according to another modification of the invention, the trimming devices are arranged along the periphery of a turntable, wherein the print products are preferably arranged on the turntable so that they do not change their alignment during the feeding. According to one modification, this is preferably achieved with an epicyclical and/or planetary gear, wherein the print products are preferably gripped by a product gripper which can be displaced for the positioning inside the trimming devices.  
         [0012]     According to yet another modification of the invention, the product gripper is displaced with the aid of control members.  
         [0013]     Additional and advantageous features follow from the dependent patent claims, the following description and the drawing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     One exemplary embodiment of the invention is explained in further detail in the following with the aid of the drawing, showing in:  
         [0015]      FIG. 1  shows schematically a three-dimensional view of an apparatus according to the invention.  
         [0016]      FIG. 2  shows schematically the individual positions of the print products during the alignment, the trimming, and the discharge.  
         [0017]      FIG. 3  shows schematically a three-dimensional view of the positioning device.  
         [0018]      FIG. 4  shows schematically a three-dimensional view of the feeding device.  
         [0019]      FIG. 5  shows schematically a three-dimensional view of a product grippe.  
         [0020]      FIG. 6  shows schematically a three-dimensional view of a trimming device.  
         [0021]      FIGS. 7   a - 7   d  show schematically the mode of operation of the trimming device.  
         [0022]      FIG. 8  shows schematically a three-dimensional view of the discharge device. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     Referring to  FIG. 1 , there is shown an apparatus  1  which is used for trimming print products  2  supplied to apparatus  1  in a rough format. Print products  2  are perfect-bound book blocks, for example, or stitched or otherwise bound brochures or magazines and the like. Apparatus  1  comprises a positioning device P in which the as yet untrimmed print products  2  are aligned. Following the positioning, the print products  2  are displaced by a certain amount in a linear direction with an intake gripper  16  and are then transferred to a product gripper  21 . With the aid of a feeding device Z, the print product  2  is then successively fed to a first trimming device S 1 , a second trimming device S 2 , and a third trimming device S 3 . The print product  2 ′″, which is trimmed along three sides, is finally supplied to a discharge device A. From this discharge device A, the trimmed product is moved to different processing stations or is shipped.  
         [0024]     When feeding the print products  2  to the individual trimming devices S 1  to S 3  and then to the discharge device A, the alignment of the print products  2  is not changed, as is clearly shown in  FIG. 2 . The alignment is also not changed if the print product  2  is transported from the positioning device P by the intake gripper  16  to the product gripper  21 , wherein the displacement  71  for the transport given in  FIG. 2  is linear as well as horizontal. In addition, the displacement can also be adapted to the top cut in the trimming device S 3 . The end position  80 , shown in  FIG. 2 , can be adjusted by correspondingly changing the displacement  71 .  FIG. 2  shows that the print products  2  to be trimmed pass through seven positions and/or stations. In position I, the print products  2  are aligned, while in position II, which is a transition position, the print products  2  are gripped by the product gripper  21 . In position III, the bottom of print product  2  is trimmed by cutting a bottom section  6  off the print product  2 . The print product  2 ′, which has been trimmed on one side, is then supplied to the position IV where the front section  5  is trimmed off. The print product  2 ″ that has been trimmed on two sides is supplied to the position V where a top section  4  is cut off. The print product  2 ′″, which is now trimmed on all three sides, is then transported to the position VI where it is gripped by a discharge gripper  60  and transferred to the position VII where the print product  2 ′″ is transported away. In the positions III and IV, the print products  2  are respectively displaced with a controlled movement and positioned precisely for the respective trimming step. The product is displaced corresponding to the format and the width of cut-off sections  6  and  5 . The adjustment of the position of intake gripper  16 , determines the displacement  71  and width of the section  4  that is trimmed off the top edge. As a result of the individual positioning, it is also possible to process different formats without requiring extensive conversion operations.  
         [0025]     The print products  2  that must be aligned in the positioning device P have not yet been trimmed and thus have a rough format. These print products  2  are produced in a printing machine D, which is only indicated schematically in  FIG. 2 . As a rule, a device for folding and binding the printed sheets or signatures is provided between the printing machine D and the positioning device P. These devices, which are known per se, are not shown herein. The printing machine D is preferably a digital printer which allows the production of small series. The apparatus  1  is configured such that copies of print products  2  with different formats can be processed successively, essentially without conversion operations.  
         [0026]     According to  FIG. 3 , the positioning device P is provided with a frame  7  with thereon arranged end stops  12  and  13  for aligning the print product  2 . In  FIG. 3 , the print products  2  are supplied respectively in the direction of arrow  82 . The back  3  of the printed product extends parallel to the direction of arrow  82 . The top  17  of print product  2  in this case is aligned horizontally. The print product  2  is fed to the positioning device P with the aid of a known transporting device, not shown herein, for example a belt conveyor. Of course, a specific timing is used for the feeding as well as the further processing, which is generally predetermined by the printing machine D.  
         [0027]     A slider  8  with a lift drive  9  is provided for positioning the print products  2  against the end stop  13  along the back  3 . The print products  2  are fitted against the end stop  13  with this slider  8  as soon as the top of the print product  2  is positioned against the end stop  12 . The end stop  12  extends crosswise to the direction of arrow  82  and can be displaced vertically between the working position, shown in  FIG. 3 , and a lower retracting position by means of a control cylinder  20 .  
         [0028]     If a print product  2  is aligned against the end stops  12  and  13 , the end stop  12  is moved down into the retracted position and the print product  2  is gripped by the intake gripper  16 . The intake gripper  16  is positioned such that it can be displaced along a guide  14 , meaning it can traverse to a limited degree back and forth along this guide  14  with the aid of a drive  15 , e.g. a control cylinder.  FIG. 3  shows the intake gripper  16  in a position in which a print product  2  is removed from the support on the frame  7 , wherein the alignment of product  2  is not changed during this linear horizontal movement, as can be seen.  
         [0029]     For gripping the print product  2 , the intake gripper  16  is provided with a height-adjustable upper jaw  19 , as well as a sliding carriage  18 . The product  2  is clamped in between the jaw  19  and the sliding carriage  18 . Once the aligned print product  2  moves away, the end stop  12  again moves upward into the position shown in  FIG. 3 , so that a following print product  2  can be aligned. The displacement  71  can be adjusted, as mentioned, for the top trimming. The end positions  79  and  80  of the intake gripper  16  are shown in  FIG. 2 . The virtual top trimming edge is drawn in with a dash-dot line  72  in positions I and II. The intake gripper  16  positions the print product  2  in the position II, such that the virtual top trimming edge  72  extends through the product  2  corresponding to the intended width of the trimming section  4  on the top.  
         [0030]     In the position II, the print product  2  is gripped by the product gripper  21 . The intake gripper  16  opens up automatically and moves back to the position I where it grips the following product  2 . The transfer of product  2  in position II from the intake gripper  16  to the product gripper  21  occurs without change in the alignment of print product  2 . In position II and in position I, the transfer furthermore occurs such that the back  3  extends along a joint line  83 .  
         [0031]     The print product  2  is moved with the feeding device Z from the position II to the position III. This movement occurs in counter-clockwise direction around a vertical axis  77 , wherein the movement could also be in clockwise direction with a corresponding apparatus. The angle of rotation in the present case is 72°. To realize this movement, the product gripper  21  is arranged on a spur gear  39  of a planetary gear  36 , as shown in  FIG. 4 . The epicyclical and/or planetary gear  36  is a five-fold gear, provided with a fixedly connected central gear  37 , five rotating intermediate gears  38 , as well as five rotating outer spur gears  39 . The intermediate gears  38  are positioned rotating on a gearwheel  41 . The spur gears  39  are respectively positioned on a web  40 . The translation ratio is respectively 1:1, so that during the rotation, the alignment of the spur gears  39  always remains the same. Accordingly, the product grippers  21  and the therewith gripped print products  2  always have the same alignment during the rotation. Thus, the back is always parallel to line  83  in  FIG. 2 . The planetary gear  36  forms a turntable  67 , which is partially covered by a disc-shaped cover  78  ( FIG. 1 ).  
         [0032]     A product gripper  21  is positioned on each spur gear  39 . On the whole, five product grippers  21  are provided which can be moved by the planetary gear  36  in counter-clockwise and/or clockwise direction. The product grippers  21  are respectively moved synchronously and/or are stopped simultaneously.  
         [0033]     The product grippers  21  have identical designs.  FIG. 5  shows that the product grippers  21  are provided with a base plate  23  which is mounted on one of the spur gears  39 . The base plate  23  contains a guide groove  84  in which a first slider  24  is positioned such that it can be displaced. The slider  24  can be displaced in the directions of double arrow  29 , by means of a roll  30  that is positioned on the slider  24 , as can be seen. The displacement in  FIG. 5  toward the bottom left occurs as a result of the counteracting force of a tension spring  26 . An additional plate  85  is mounted on the first slider  24 , which also contains a guide groove  86 . This guide groove  86 , however, extends at a right angle to the groove  84 . A second slider  25  that can be displaced in the directions of double arrow  28  is positioned displaceable inside this additional groove  86 . Again, the displacement occurs by means of a roll  31 , which is positioned on the slider  25 . According to  FIG. 5 , the second slider  25  can be displaced toward the upper left and counter to the resetting force of a tension spring  27 . A support  22  is mounted on the second slider  25  which forms a fixed lower clamping jaw  32  on which an upper clamping jaw  33  is positioned so as to be height-adjustable with two guide rods  34 . The clamping effect is ensured with the aid of tension springs  35 . Pneumatic means can be used, for example, for lifting the upper clamping jaw  33  and opening the product gripper  21 .  
         [0034]     The two sliders  24  and  25  extend at a right angle to each other, as previously mentioned. The upper slider  25  extends parallel to the back  3  and the lower slider  24  extends parallel to the top edge and the bottom edge of the gripped print product  2 . By displacing the sliders  24  and  25 , the print product  2  can thus be displaced parallel to the back  3  or transverse to it, wherein the alignment is maintained.  
         [0035]     Control members  42  to  45  are arranged along the periphery of the planetary gear  36  for displacing the sliders  24  and  25 . These control members  42  to  45  engage in the roll  30  or  31  for the displacement. The control members  42  to  45  are positioned displaceable in elongated holes  87  to  89 , wherein the drive for displacing the control members  42  to  45  is not shown herein. The control member  42  functions to advance the sliders  25  for the bottom cut and the control member  43  functions to return the slider  25  to its original position. The control member  44  functions to advance the slider  24  for the front cut and the control member  45  serves to reset the slider  24 . For the movement of product gripper  21  from position II to position III, the control member  42  operates jointly with the roll  31 , thus positioning the print product  2  precisely in the trimming device Si. Once the print product  2  is correctly positioned in the trimming device S 1 , the feeding device Z and/or the planetary gear  36  are stopped in order to realize the trimming operation. Following the completion of the trimming operation, the print product  2 ′, which is trimmed on one side, is moved to the position IV. The slider  25  is returned to the starting position with the control member  43 . At the same time, the control member  44  positions the print product  2 ′ in the second trimming device S 2  for the front cut. Once the print product  2 ′ is positioned in the second trimming device S 2 , a front cut is carried out with the trimming device S 2 , wherein the feeding device Z is again stopped for this operation.  
         [0036]     The print product  2 ′′, which is now trimmed on two sides, is then moved further in counter-clockwise direction by 72° to the third trimming device S 3 . During this movement, the control member  45  moves the slider  24  back. No advancement is required for the top cut since the corresponding position is already fixed by the end position selected in position II.  
         [0037]     Once the top is trimmed in the trimming device S 3 , the print product  2 ′″ which is trimmed on three sides is moved to the position VI, wherein this movement is also a counter-clockwise movement by 72°. In the position VI, the back  3  is positioned along the line  83 , as shown in  FIG. 2 .  
         [0038]     The print product  2 ′″ is then transferred to the discharge device A, which comprises a frame  90  with thereon arranged transporting device  65 , as shown in  FIG. 8 . This transporting device  65  has a table  67  around which transport belts  66  are fitted. In addition, the table  67  is provided with an end stop  68  on the side. According to  FIG. 8 , the trimmed print product  2 ′″ is transferred to the transport device  65  in the direction of arrow  70 . A discharge gripper  60  is provided for this, which can be moved with the aid of a slide carriage  63  in the direction of arrow  70  as well as in the opposite direction. The discharge gripper  60  is moved back and forth with the aid of a drive  64 . In order to grip the print product  2 ′″, the discharge gripper  60  is provided with a lower clamping plate  62  as well as a clamping jaw  61  for gripping the top of print product  2 ′″, as shown in  FIG. 8 , and for moving it onto the transporting device  65 , wherein the alignment of the print product is again preserved. Once the print product  2 ′″ is positioned on the transporting device  65 , the discharge gripper  60  opens up and moves back to the starting position shown in  FIG. 8 . The feeding device Z is stopped while the print product  2 ′″ is moved onto the transport device  65 . During this transport, a rough print product  2  is simultaneously moved from position I to position II as shown in  FIG. 2 . Corresponding trimming steps are realized at the same time at the three trimming devices S 1  to S 3 . These actions are synchronous and are controlled by a control device not shown herein.  
         [0039]     If a print product  2  with a different format is to be trimmed, the control members  42  to  45  are changed accordingly and the displacement  71  is also adapted to the new format. The conversion can occur automatically with the aforementioned control device and suitable adjustment drives.  
         [0040]     In the following, the mode of operation of the trimming devices S 1  to S 3  is explained with the aid of  FIGS. 6 and 7   a  to  7   d . These trimming devices S 1  to S 3  are preferably identical in design.  
         [0041]     The trimming device S 1  in  FIG. 6  is provided with a housing  46  on which is disposed a lower knife  47  that is rigidly connected to the frame, as well as a vertically movable knife holder  50  with an upper knife  49 . In addition, a pressure plate  48  is positioned at the lower end of a piston rod  52  of a pressure cylinder  51 . The pressure cylinder  51  has an upper pressure chamber  58 , as shown in  FIGS. 7   a - 7   d , and a lower pressure chamber  59  with connections  53  and  54 . In addition, a first initiator  56  and a second initiator  57  are connected to the knife holder  50 . A third initiator  55  has a fixed position with respect to the lower knife  47 .  FIG. 7   a  shows the starting position where the knife holder  50  is at an upper dead point. If the trimming device S 1  is activated while no print product  2  is positioned therein, the pressure plate  48  moves downward. However, no pressure is exerted onto the pressure plate  48  since the first initiator  55  responds in the corresponding position and the pressure balance between the upper pressure chamber  58  and the lower pressure chamber  59  is maintained.  
         [0042]     If the trimming device S 1  contains a print product  2  with the defined thickness range as shown in  FIG. 7   c , then the pressure plate  48  moves downward. The first initiator  55  in that case does not respond. However, the second initiator  56  responds and the lower pressure chamber  59  in the pressure cylinder  51  is thus ventilated. As a result of the still existing pressure in the upper chamber  58 , a pressure is built up that is exerted onto the pressure plate  48  and this pressure plate  48  subsequently clamps the print product  2  onto the lower knife  47 . The knife holder  50  with the upper knife  49  can then move downward with the aid of a drive, not shown herein, for the trimming operation. In that case, the pressure cylinder  51  with the knife holder moves downward. Following the upward movement of the knife holder  50 , the starting position according to  FIG. 7   a  is reached once more.  
         [0043]      FIG. 7   d  shows a trimming device Si with therein positioned print product  2 , for which thickness exceeds the defined range. In accordance with the higher thickness, a part  91  on the pressure plate  48  is positioned at the respective height. Once the pressure plate  48  rests against the excessively thick product  2 , the third initiator  57  responds and a corresponding signal will immediately stop the trimming device S 1 .  
         [0044]     The invention has been described in detail with respect to referred embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention.