Patent Publication Number: US-6655674-B2

Title: Arrangement for stitching the spine of printed products, compiled of folded printed sheets, by means of staples

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an arrangement for stitching the spine of printed products, compiled of folded printed sheets, by means of staples, wherein the printed products are transported by means of a conveying device, with the spine transverse to the conveying direction and at a spacing sequentially behind one another, to a stitching device comprised of a stitching head/bending arrangement. 
     2. Description of the Related Art 
     Devices of this kind are used, inter alia, in so-called gather-stitchers where loosely collected printed sheets are combined to printed products that are supplied to a stitching device downstream of the collecting stretch. 
     In newspaper production pre-products are inserted into a main product. For some time now, newspapers have issued in a tabloid format which is comprised of several parts which are stitched by staples in rotation. These printed products are considered reader-friendly and have a higher quality standard. 
     Such printed products could be further improved in the interest of the publisher as well as the reader such that the printed product as an entire product is stitched only once. 
     In the newspaper production there is also the desire for a more economic use of an insertion machine, for example, by means of the possibility of stitching inserted printed products, wherein the quality of such printed products could be further improved, for example, with a special envelope and/or a subsequent trimming of the printed products. 
     Devices of the aforementioned kind are described, inter alia, in Swiss patent application CH-A-667 621 and German patent document DE-B-36 45 276 as well as realized in the form of the gather-stitcher Combi Drum of the company Ferag AG, Hinwil, Switzerland. The devices used in this context for stitching printed products require a high mechanical expenditure, in particular, because each saddle-shaped support comprises a bending device so that for 40 and more supports on a drum a high expenditure results which is also noticeable in the maintenance costs. 
     The stitching of printed products which are inserted into pockets with their fold leading is described in German patent document DE-B-1 224 329 wherein the pockets for receiving the printed products are secured on a revolving drum in a perpendicular position and pass in the lower area of the drum a stationary stitching device which has a bending device, dipping into the pocket in a radial direction to the drum axis, and a stitching head on the opposite side interacting with the bending device. This stitching device does not allow a economic processing output because of the long travel stroke of the bending device. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a device of the aforementioned kind which no longer has the aforementioned deficiencies and which can be produced easily. 
     In accordance with the present invention, this is achieved in that the stitching device is embodied as a stitching support having a stitching head/bending arrangement and driven during the stitching process approximately in the same direction and at least approximately with the same speed as the conveying device. 
     In the following the invention will be described in the form of several embodiments illustrated in the drawings; reference is being had to the drawings in regard to all details not described specifically in the specification. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the drawing: 
     FIG. 1 shows a schematic illustration of one embodiment of the device according to the invention; 
     FIG. 2 is a schematic illustration of an alternative embodiment; 
     FIG. 3 is a cross section along the line III—III of FIG. 2; 
     FIG. 4 is a stabilizing device; 
     FIG. 5 shows the stabilizing device according to FIG. 4 with changed format size of the printed products; 
     FIG. 6 shows a bending device; 
     FIG. 7 shows a side view of the bending device according to the direction of arrow A in FIG. 6; 
     FIG. 8 shows a stitching wire supply device; 
     FIG. 9 shows stitching of the printed products with the device according to the invention on saddle-shaped supports; 
     FIG. 10 shows a schematic illustration of an alternative embodiment of the device according to the invention; 
     FIG. 11 shows a cross-section along the line X—X in FIG. 10; 
     FIG. 12 is a schematic illustration of an alternative embodiment of the device according to the invention; and 
     FIG. 13 is a schematic illustration of a further alternative embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 1 a device  1  for stitching the spine of printed products  2 , which are compiled of folded printed sheets, by means of staples is illustrated, wherein the printed products  2  are inserted into insertion pockets  3  of a conveying device  4  with their fold leading. The conveyor  4  is, for example, an insertion machine in which the pre-products are inserted into a main product. This process for manufacturing newspapers is known and therefore does not require any detailed discussion. The insertion pockets  3  are fastened on both ends on circulating chains and have means for opening and keeping open the printed products supplied thereto. In the illustrated situation, the legs of the printed sheets inserted into one another rest against the walls  5 ,  6  of the pockets  3 . The pockets  3  are, for example, embodied like those described in European patent application 0 475 192 A2. Supports of the printed products in the insertion pockets  3  are embodied as height-adjustable brackets (pocket bottom elements) forming the bottom of the insertion pockets  3  which are matched to the format of the printed products. As a result of the varying fold thickness of the printed products  2 , it may be advantageous when the stitching support  7  or the conveying device  4  is adjustable relative to the outer fold edge of the printed products  2  so that the fold in the transition area of the insertion pocket  3  or support to the stitching support  7  is not bent. The pocket bottom elements are inwardly staggered so that the stitching heads  9  and bending devices  10  can cooperate unimpairedly. The insertion pockets  3  are suspended from a conveying chain circulating in a guide and the lower end is arranged to be leading so that the insertion pockets have a backwardly slanted position. This position however is of no relevance to the device of the invention. In the area of the pockets  3 , the conveying device  4  passes a stitching support  7  arranged underneath which rotates at the tangential contact point in the same direction and at the same speed as the conveying device  4 , wherein on the circumference of the stitching support  7  a stitching head/bending arrangement  8  is provided which is comprised of several paired cooperating stitching heads  9  and bending devices  10  which are correlated with a passing insertion pocket  3 ; this means that the stitching support  7  advantageously has a smaller number of stitching head/bending pairs than the number of insertion pockets  3  on the conveying device  4 . FIG. 1 shows that the conveying device  4  has a curved course relative to the stitching device  1 . The reason for this are the constructive height which, as a result of the required access for the operating personnel, must be adjusted ergonomically, as well as a stitching stretch where the stitching process is performed and which is to be optimally configured. This is described in German patent document DE-B-36 45 276. 
     Of course, it is also possible, as illustrated in FIG. 2, to position the conveying device  4  horizontally tangentially in the area of the stitching device  11 . In FIG. 2, it is shown that the stitching angle of the bending device  10  between the immersion into and the pivoting out from the insertion pocket  3  is smaller than for a curved conveying device  3  so that there is also less time available for stitching. 
     FIG. 1 also discloses the relative course of the insertion pocket  3  and of the stitching head/bending arrangement  8 . In this connection, reference is being had also to FIG. 3 which shows a cross-section of the stitching device  11  in the insertion pocket area. The stitching device  11  is arranged respectively in the lateral area of the passing insertion pocket  3 . On a drive shaft  12 , which is supported on the machine frame  13  and is driven synchronously with the cycle of the conveying device  4 , the stitching support  7  is fastened on which a stitching head/bending pair is fastened on each side, respectively. In the illustrated embodiment, the stitching support  7  is comprised of two outer disks  14  on which the bending devices  10  are fastened and two oppositely positioned inner stitching head disks  15  on which the stitching heads  9  correlated with the bending devices  10  are fastened, respectively. According to FIG. 7 wire sections, cut to size with a dispensing device  48 , are transmitted by means of follower  49  to the stitching head  9  and, during this transfer, are shaped by a bending member  16  arranged on the stitching head  9  to a C shape (see also European patent application EP 0 629 515 A1). The thus prepared staple is subsequently pushed by a driver  17  of the stitching head  9  through the fold of the printed product  2  and bent on the opposite side by an anvil  18  of the bending device  10 . The actuation of the driver  17  is realized by a tooth segment  19  which is driven by a control curve  23  (FIG.  3 ). 
     Since the stitching process lasts for a certain duration and therefore results in a certain stitching stretch, it is advantageous when the bending member  16  has already contact with the sheet before penetration of the staple. For this reason, the bending member  16  guiding the staple into the stitching area could be prematurely brought into sheet contact for which purpose a lever  20  is provided, respectively, which is controlled by a curve  22  and which acts on the bending member  16 . The levers  20  are pivotably supported on an axle  21  and are connected at their free end with the bending member  16 . This technical detail is also illustrated in FIG.  3 . 
     In FIG. 1 it is also shown that the stitching head  9  and the bending device  10  are cooperating in a common stitching plane. FIG. 1 shows several sequences of a stitching process. In the 11 o&#39;clock position of the stitching support  7 , the stitching head  9  and the bending device  10  are in an inoperative position, as illustrated in FIG. 3 at the bottom. A sequence step later, these members are still in the initial position but a few degrees later, or immediately thereafter, the driver  17  (and the bending member  16 ) as well as the bending device  10  are activated by their correlated control curves  22 ,  23 ,  24 . In the 12 o&#39;clock position, which is also illustrated in FIG. 3, the staple has penetrated the fold and is bent. From this time on, the driver  17 , and, if activalable, also the bending member  16 , and the bending device  10  leave the closing position. Decisive on the path into the stitching position is that the anvil  18  of the bending device  10  dips into an insertion pocket  3  without damaging the printed product  2  contained therein; the exit of the anvil  18  from the insertion pocket  3  must be determined as precisely—however, these are no difficult prerequisites for a successful functioning. A wedge-shaped pocket shape is beneficial for this purpose in that the common stitching plane of the stitching head  9  and bending device  10  extends tangentially to a concentric circle within the stitching circle wherein the stitching plane at the point of staple penetration up to the final closing of the staple extends approximately through the longitudinal center area of an insertion pocket  3  (see FIG.  1 ). 
     The situation of the staple closure and the constructive means for this are illustrated in FIG.  3 . The bending devices  10  have an anvil  18 , respectively, which is pivotably supported on a support  26  forming a guide  25 . In the guide  25  a sliding block  27  is connected via a roller  28  with a control curve  24  which causes a sliding block movement and actuates a tooth rack  29  which is in driving connection with the sliding block  27  and guided in the support  26 . The movements of the toothed rack  29  are transmitted onto a pinion  30  which pivots the anvil  18  of the bending device  10  back and forth into the stitching position and into the initial position, respectively. In the case of an unforeseen overload, for example, when a greater thickness of the fold is to be stitched, an overload protection responds which is formed by a rod  31  penetrating the toothed rack  29  in the movement direction and a pressure spring  32  which is positioned between the sliding block  27  and the movable toothed rack  29  as well as a nut or adjusting ring  33  securing the toothed rack  29  on the rod  31 . During action of the driver  17  on the anvil  18 , the latter is supported by means of a lever arm  34  connected thereto on a partial support path  36  concentrically arranged to the axis of rotation  35  of the rotating stitching support  27 . This arrangement is also shown in FIGS. 5 and 6. Moreover, the FIGS. 3,  6  and  7  show an additional device which is favorable in regard to the quality of the staple which ensures that the legs of the staple rest against the inner fold edge. This second bending means is integrated into the bending device  10 . It is comprised of an articulated lever  37  which has a control-active lever arm  38  and an actuator arm  39 . The control-active lever arm  38  moves onto a partial control curve  40  when the staple is bent and effects that the lever arm  39 , connected with the wing-like bending elements  41 , pivots the latter suddenly against the at least partially bent staple legs. By means of the pressure spring  42 , the bending elements  41  are moved into the initial position. 
     FIG. 7 shows the bending device  10  as well as the correlated device, provided with pivotable bending elements  41 , before lifting out of the stitching position and in the inoperative position. 
     At the same time, FIG. 6 shows the position of the bending device  10  in a view directed onto the side of the stitching support  7 . 
     The left illustration shows the anvil  18  in the stitching position according to FIG.  7  and FIG. 3, upper stitching support area. As a result of the common stitching plane of the bending device  10  and the stitching head  9  which deviates from the radial direction, the toothed rack  29  and the pinion  30  have a helical gearing. The right illustration in FIG. 6 of the bending device  10  shows it in the initial position as, for example, in the lower area of the stitching support  7  in FIG.  3 . 
     Instead of the pivot movement of the bending device  10  illustrated in the Figures, the device  10  could be moved by other advancing movements into the stitching position, for example, by a linear or a combined advancing movement wherein the movement is carried out in the stitching plane which is positioned between the walls  5 ,  6  of an insertion pocket  3 . 
     The pocket bottom elements  45  forming the lower end of the insertion pocket  3  are arranged within the area between the stitching heads  9  and the bending devices  10  acting from both sides so that the latter have an unimpaired access to the stitching position. The insertion pockets  3  are advantageously configured on both sides with a recess  44 . The walls  5 ,  6  formed by sheet metal of the suspended insertion pockets  3  form as a result of the relatively large insertion depth an unstable lower end so that a precise stitching cannot be performed reliably. For obtaining a high stability and positional precision of the insertion pockets  3  during stitching, two spaced-apart centering wheels  46  are in driving connection with the rotating stitching support  7 . They have gaps  47  arranged on their periphery at a spacing corresponding to that of the insertion pockets  3  of the conveying device  4  and the insertion pockets  3 , with their suspended ends or the pocket bottom brackets  45 , dip in a positive-locking way into the gaps so that a high stability and sufficient precision of the insertion pockets  3  is ensured. 
     FIGS. 4 and 5 show a stabilizing device formed of centering wheels  46  wherein the axially staggered centering wheels  46  have on their circumference gaps  47  distributed at a spacing corresponding to that of the insertion pockets  3  into which pivotable cams  46  arranged on the suspended end of an insertion pocket  3  will dip, respectively. The centering wheels  46  are formed by rings  53  screwed onto the stitching head disks  15  and provided with the gaps  47  on their outer diameter. The stitching head disks are provided with ribs  55  for reinforcement. The pocket bottom brackets  45  are guided adjustably in guides  54  and adjusted to the format of a printed product  2 . FIG. 4 differs from FIG. 5 because of the different formats of the printed products, wherein in FIG. 4 a printed product  2  of a minimal width in comparison to FIG. 5 is inserted and the pocket bottom brackets  45  are adjusted in the height position such that the printed products  2  with the open lateral edges are approximately in the same position in order to be opened via a gripping fold and to be removed from the insertion pocket  3 . 
     As a result of the height adjustability of the pocket bottom brackets  45 , the stitching support  7  must be adjustable, i.e., the latter is configured to be adjustable relative to the passing pocket bottom brackets  45  in regard to its height, as illustrated in FIGS. 4 and 5. 
     Of course, it would be possible constructively to arrange the stitching support  7  stationarily in this respect and to make the conveying device  4  adjustable in the stitching area; however, this appears to be more cost intensive. 
     In FIG. 9, the device  1  according to the invention is shown in cooperation with a conveying device  4  which supports the printed products  2  astraddle on saddle-shaped supports  50 , wherein the conveying device  4  is a so-called ladder principal as disclosed, for example, in European patent document EP-A-0 095 603. 
     Of course, the inventive device  1  can also be used with a so-called drum gather-stitcher instead of those described in European patent documents EP-A-0 399 317, 0 476 718, 0 546 326, 0 569 887, 0 606 555 with significantly reduced constructive expenditure. With respect to FIG. 9, the printed products  2  are transported on supports  50  oriented transversely to the conveying direction F. The supports  50  are secured on lateral rollers  51  guided in connecting link guides and extend approximately tangentially relative to a stitching circle defined by a stitching head/bending arrangement  8  fastened on a stitching support  7 . As already noted in connection with FIG. 2, a straight tangent would result in a shorter stitching stretch. FIG. 9 shows again sequences of the stitching process on the conveying device  4 . In the 5 o&#39;clock position, the stitching device  11  formed of the stitching head  9  and the bending device  10  has reached the stitching stretch where the stitching process is started. The bending member  16  loaded with a staple, if furnished accordingly, is brought into contact with the spine of the printed products  2  and directly thereafter the stitching action is started between 6 o&#39;clock and 7 o&#39;clock, i.e., the anvil  18  of the bending device  10  is moved or pivoted into the stitching position and the stitching stroke of the driver  17  is triggered. As described above, the bending device  10  can be provided with actuatable bending elements  41  which exert an additional movement onto the staple legs. 
     Moreover, FIG. 8 illustrates a wire section dispenser  48  which shapes the cut-off wire sections upon transfer to the stitching heads  9  or the bending member  16 . 
     An alternative device  1  according to the invention is illustrated in FIGS. 10 and 11 which can be used in connection with inserted printed products as well as with printed products which are transported astraddle on a support. The illustrated embodiment is provided for the stitching of a printed product  2  transported in insertion pockets  3 . For this purpose, as already illustrated in FIG. 2, a conveying device  4  with insertion pockets  3  fastened sequentially at a spacing on a traction device is provided. 
     Parallel to the conveying direction F, at least along a stitching stretch on which the staples are anchored in the printed products  2 , the stitching support  7  formed as a slide  60  is guided back and forth in a guide  62 . This means that the stitching devices  11  aligned according to the pocket slant follow the insertion pockets  3  on the stitching stretch. For this purpose, the slide  60  is connected with a crank gear  61  which is driven by a symbolically illustrated, preferably rotary angle-controlled or rotary angle-governed electric motor  63 . FIG. 10 shows a crank wheel  64 , crank pin  65  and a coupling  66  connecting it and the slide  60 . The active length of the guide  62  is illustrated on both sides of the slide  60  by dash-dotted lines. A double arrow Z indicates the reciprocating movement of the slide  60 . The rotary angle-controlled or rotary angle-governed electric motor  63  ensures that the slide  60  or the stitching devices  11  connected thereto can follow the insertion pockets correlated with the stitching at identical speed and in the same direction. The embodiment according to FIG. 10 provides two stitching device pairs which are arranged sequentially at a spacing transversely to the conveying direction or the slide movement, wherein each stitching device pair has a stitching device  11  at the end face of an insertion pocket  3 , respectively. Of course, the use of a single stitching device pair would be possible but the return stroke of the slide  60  would require higher accelerations in order to be available for the next stitching process; or, the speed of the conveying device  4  for a single stitching device pair would have to be reduced significantly. Of course, more than two stitching device pairs could be placed onto the slide  60 ; however, this would require the acceleration of greater masses. 
     When comparing this arrangement with FIG. 9, instead of the conveying device  4  with insertion pockets  3  it would also be possible to employ a conveying device  4  for stitching products  2  resting astraddle on supports  50 . 
     With respect to FIGS. 10 and 11, the slide  60  has the same stitching head/bending arrangement  8  as already illustrated in FIGS. 1 through 8. The slide  7  provided as the stitching support  7  and the stitching head/bending arrangement  8  fastened thereon form again a unit which can be used for stitching of inserted printed products  2  as well as of printed products which are transported astraddle. 
     The difference resides in rotating versus linearly moved stitching supports  7 . Different are the drive means for the bending member  16  and the driver  17  in the stitching heads  9  in the illustrated embodiments. 
     FIG. 11 illustrates in cross-section the guide  62  formed of two rods on which the slide  60  is reciprocatingly drivable perpendicularly to the drawing plane. On the slide  60 , laterally to the insertion pockets  3  suspended from the guided traction means  52 , two stitching devices  11  are fastened which, together with the oppositely positioned stitching devices  11 , form pairs for stitching printed products  2 . FIGS. 9 and 10 show oppositely positioned bending devices  10  with anvils  18  pivoted into the stitching position, which has been realized by actuation of a toothed rack  29  movable in a guide  25 . The toothed rack  29  is connected with a sliding block  27  on which a roller  28  is fastened which is seated in a control curve  24 . The connection of the sliding block  27  and toothed rack  29  is achieved by a connecting rod  31  on which, between sliding block  27  and tooth rack  29 , a pressure spring  32  is arranged as a protection against overload. An adjusting ring or a nut  33  on the connecting rod secures the connection of the sliding block  27  and the toothed rack  29 . The toothed rack  29  engages the pinion  30  supported on the slide  60  and connected fixedly with the bending device  10  in the form of an articulated lever  37  (see also FIG.  7 ). As already shown and described in connection with FIG. 7, in the embodiment according to FIGS. 10 and 11 a lever arm of the articulated lever  37  is provided for a positive-locking support of the actuator arm  39  or anvil  18 . 
     The drive of the stitching heads  9  is provided in the form of a gear  67  connected with a crank wheel  64  which connects by means of a drive belt  68  to a stationarily supported drive wheel  69 . Of course, other known drive means can be employed. The transmission of the movement of the gear  67  onto one or more stitching heads  9  (stitching drive) is realized first as a result of the reciprocating movement of the slide  60  by means of a telescoping universally jointed shaft  70  onto a chain gear  71  which drives a stitching head shaft  72  extending transversely to the reciprocating movement of the slide  60 . On the ends of the stitching head shaft  72  supported on the slide  60  an eccentric disc  73  with an eccentric pin  74  is fastened which penetrates, parallel to the stitching head shaft  72 , a bending link  75  and a driver link  76 , arranged in a connecting link guide  79 , which are drivingly connected with the stitching head  9 . The bending link  75  connected to the bending member  16  of the stitching head  9  has a control curve which is arrow-shaped relative to the movement direction of the stitching head  9 , illustrated by the double arrow H—referred to as the bending curve  78 —which is penetrated by the eccentric pin  74  in the bending link  75 ; the driver link  76  connected drivingly with the driver  17  has a slantedly extending control curve relative to the movement direction of the stitching head  9 —here referred to as driver curve  78 —which penetrates behind the bending link  75  the driver link  76 . The bending member  16  and the driver  17  are provided with extensions  80 ,  81  for connecting them to the bending  75  and driver links  76 . As a result of the slanted position of the insertion pocket caused by the leading lower end thereof, the stitching device  11  is arranged accordingly, i.e., the stitching plane in which the stitching head  9  and the bending device  10  are being moved, are positioned approximately within the bisecting line of the angle which is formed by the walls  5 ,  6  of the insertion pocket  3 . The actuation of the bending device  10  can be triggered already before the point of coinciding of the insertion pocket  3  and the stitching plane, but the anvil  18  may dip into the insertion pocket  3  only when the printed product spread open within the insertion pockets  3  provides sufficient free space. 
     Otherwise, the stitching process in the embodiment according to FIGS. 10 and 11 and the requirements therefor do not differ from the technical measures of the embodiments of the preceding figures. 
     A further discussion of FIGS. 10 and 11 is therefore not required in view of the general knowledge of a person skilled in the art. 
     Another embodiment according to the invention is illustrated in FIG. 12 in which the stitching support  7  is a rocker  90  which is oscillatingly driven on the pivot axis  91 . On the pivotable end of the rocker  90  two stitching device pairs of the stitching head/bending arrangement  8  are arranged, as in the embodiment according to FIGS. 10 and 11, which act stitchingly on the printed products  2  transported on a radially curved path in the insertion pockets  3  of a conveying device or in the insertion pockets  3 . The pivotably reciprocating stitching heads  9  and the lower end of the insertion pockets  3  moved on the path or the pocket bottom brackets  45  of the insertion pockets  3  form a stitching circle section on which the stitching stretch is located. The spacing of the stitching head pairs corresponds to the spacing of the insertion pockets  3  and of the pocket bottom brackets  45 , respectively, on the stitching circle section. The action of the stitching devices  11  does not differ from that of the preceding embodiments. As a result of the uniform curvature of the stitching circle and the position of the insertion pockets  3  deviating from the radial direction, the stitching planes which are defined by the movement of the stitching heads  9  and the corresponding bending devices  10  have an acute angle which opens radially outwardly. 
     The pivot movements of the rocker  90  are performed by a lever arm  92  positioned opposite the pivot axis  91  and connected with the rocker  90  which engages with the guide roller  93 , connected at its free end, a circulating endless control path  94  which is connected to a driven control shaft  95 . The rotary speed of the control shaft  95  and the shape of the control path  94  are determined such that the stitching devices  9  can follow the insertion pockets  3  and their pocket bottom brackets  45 , respectively, on the stitching stretch. 
     Endless control links  96  and  97  are moreover fixedly connected with the control shaft  95  for actuation of the bending member  16  and the driver  17  of the stitching devices, respectively. The actuation of the bending member  16  and the driver  17  is realized by the linkage  98 ,  99  which are coupled by a lever arm  100 ,  101  of an angular lever  102 ,  103 , pivotable parallel to the control shaft  95 , on the one hand, with the control links  96 ,  97  and with a further lever arm  106 ,  107 , on the other hand, with links  104 ,  105  connecting the bending member  16  or the driver  17  of the stitching heads  9 . 
     For a better understanding of the arrangement, the control links  96 ,  97  correlated with the bending members  16  and drivers  17  of a stitching head  9  are illustrated only partially on both sides of the rocker drive in FIG.  12 . 
     Otherwise, a mutual exchange of the drive concepts between the stitching support  7  according to FIGS. 10 and 11 and the embodiment according to FIG. 11 is within the capabilities of a person skilled in the art. 
     FIG. 13 shows a further device  1  according to the invention. It is designed to effect a compensation of the high mass forces according to the embodiment of FIG. 12 by distributing the stitching devices  11  onto two oppositely driven rockers  90  which at their free ends are provided with a stitching device  11  correlated with a passing insertion pocket  3 . 
     The illustration in FIG. 13 shows a situation in which the stitching device  11  is performing a stitching process and moves in the direction F with approximately the same velocity as the conveying device in the direction of arrow V. At the same time, the other stitching device  11 ′ moves in the counter direction relative to the conveying device  4  and is on its return path, i.e., no stitching process is being performed. The inwardly pivoted bending device  10  and stitching head  9  with intermediate position of a printed product  2  demonstrates that the stitching device  11  performs a stitching process. The open position between the bending device  10 ′ and stitching head  9 ′ illustrates that the stitching device  11 ′ according to arrow R is on the return path into the initial position. 
     Otherwise, the printed product  2 ′ present in the insertion pocket  3 ′ has been stapled by the stitching device  11 ′ while the printed product  2 ″ in the insertion pocket  3 ″ is still to be stapled by the stitching device  11 . The rockers  90 ,  90 ′ have a common pivot axis  91  and are connected with lever arms  92 ,  92 ′ for the actuation. The free ends of the lever arms  92 ,  92 ′ are provided with guide rollers  93 ,  93 ′ which engage a circulating endless control path  94 ,  94 ′. The control path  94 ,  94 ′ are fastened on the drivingly connected control shaft  95 . The rotational speed of the control shafts  95 ,  95 ′ and the shape of the control paths  94 ,  94 ′ are adjusted to the respective stitching process and return path such that the stitching devices  11 ,  11 ′ during the stitching process can follow the insertion pockets  3  and, upon return, can reach the initial position at their correct point in time. 
     On the control shafts  95 ,  95 ′ endless control links (not visible for actuation the drivers  17 ,  17 ′ of the stitching devices  11 ,  11 ′ are provided which are engaged by the end of a lever arm  100 ,  101  of a control lever  106 ,  106 ′. The lever arm  101 ,  101 ′, positioned opposite the pivot axis of the control lever  106 ,  106 ′, is connected by links  104 ,  104 ′ with the stitching head  9 ,  9 ′ of a stitching device  11 ,  11 ′. Further information can be taken from the embodiment according to FIG. 12 in which, inter alia, the bending members of a stitching head are driven. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.