CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application claims the priority of European Patent Application No. 02405987.5-2304 filed on Nov. 18, 2002, the disclosure of which is incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to a wire-stitching apparatus for producing wire stitched print items from printed products.  
           [0003]    Wire-stitching apparatuses of this type are known, for example, from gathering and wire-stitching machines in which different types of printed products are gathered in a gathering section to form a single print item that is subsequently stitched along a fold.  
           [0004]    In one such wire-stitching apparatus, known as “Tempo” and shown in the Muller Martini brochure 410/9708, the printed products gathered on a conveying arrangement are wire-stitched by a wire-stitching unit while the products are being transported.  
           [0005]    In an alternate gathering and wire-stitching apparatus that operates according to a similar wire-stitching principle, the printed products are transported by a conveying arrangement to a stationary wire-stitching position and stitched before being conveyed away.  
           [0006]    In a drum-type gathering and wire-stitching apparatus, printed products are conveyed on a drum rotating around a horizontal axis and are subsequently stitched while in a stationary position on the rotating drum with the aid of a stitching unit.  
         SUMMARY OF THE INVENTION  
         [0007]    It is one object of the present invention to create a wire-stitching unit that is suitable for producing stitched print items of varying thickness at high degree of reliability, but without requiring manual adjustment for devices on a wire-stitching apparatus and without reducing high production output.  
           [0008]    This and other objects are solved according to the present invention in which a wire-stitching apparatus includes a conveying arrangement for supplying folded, printed products in a straddling position; a wire-stitching unit installed at an adjustable distance above the conveying arrangement and including a bending device; at least one wire-stitching aggregate; and a stitching carriage for moving the at least one wire-stitching aggregate back and forth along a path. The wire-stitching aggregate includes a bender for forming legs of a staple and a driver for pushing the staple legs through the printed products. At least one wire feed feeds wire to the wire-stitching aggregate at a stitching wire length. At least one adjustable wire-cutting device forms a wire staple in dependence on the thickness of the printed products. A control unit performs at least one of the following functions: 1) measuring the thickness of the printed products on the conveying arrangement upstream of the wire-stitching unit, and 2) processing stored data related to the printed products.  
           [0009]    The wire-stitching unit adjusting mechanism includes at least one locally fixed means for driving the adjustment of the connected to the control unit.  
           [0010]    A mechanism for adjusting the height of the conveying arrangement includes controllable, locally fixed means for driving the adjustment.  
           [0011]    The wire feed is adjustable to the thickness of the printed products, and the mechanism for adjusting the wire feed includes a driver for driving the adjustment, a drive shaft extending through the stitching carriage parallel, and at least one gear having at least one drive wheel displaceably mounted on the drive shaft and being assigned to the one stitching aggregate.  
           [0012]    The wire feed can include two friction wheels for transporting the wire and a wheel arrangement driving the friction wheels.  
           [0013]    The gear can be a miter gear.  
           [0014]    The wire-cutting device can include a blade holder that can be adjusted to the thickness of printed products. The wire-cutting device adjusting mechanism includes a follower pin arranged on the blade holder that engages a guide track extending at a slant relative to the path of the stitching carriage and coupled via a height-adjustable guide rail to at least one torque-controlled electric motor.  
           [0015]    The guide rail can include a guide member, and the wire-cutting device adjusting mechanism can further include drive cams arranged on the blade holders and a cam rail attached to the stitching carriage acting upon drive cams of the blade holders such that the cam rail can be driven back and forth inside the guide member of the guide rail.  
           [0016]    The wire-cutting device can include an adjusting mechanism having a follower pin on the blade holder that engages in a guide track extending at a slant to the path of the stitching carriage and a lever arrangement connecting the guide track to a driver.  
           [0017]    The driver of the guide track can include an electric motor, a shaft extending through the stitching carriage parallel to the path and connected to the electric motor, at least one lever connected to the shaft, a guide rod connected to the at least one lever, and a cam rail actuated by the guide rod.  
           [0018]    The wire-stitching apparatus can further include a bending device that can also be adjusted to the thickness of the printed products. The bending device can include at least one bending block, an adjustable bending support supporting the at least one bending block, and a mechanism for adjusting the bending support. The bending support adjusting mechanism can include a gear, a drive shaft attached to the gear, and a locally fixed, torque-controlled electric motor for driving the drive shaft.  
           [0019]    The bending support adjusting mechanism can further include a toothed segment drive-connected to the bending support, a stationary toothed rack that can be moved along with the toothed segment, and a lever arm arranged on the drive shaft of the electric motor and connected to the toothed segment.  
           [0020]    The bending support adjusting mechanism can further include a shaft-hub connection extending through the stitching carriage for connecting the drive shaft to the lever arm. The shaft-hub connection can transmit torque when displaced by the drive shaft. The electric motor can be adapted to accommodate overload.  
           [0021]    The conveying arrangement can also be adjustable to the thickness of the printed products and include a chain guide, at least one link chain circulating on the chain guide, and a roof-shaped support with individual members attached to the chain guide. The chain guide can include downwardly extending lifters, and conveying arrangement adjusting mechanism can include lever gears attached to a drive shaft.  
           [0022]    The torque of the electric motor can be preset for operation. The drivers provided for the individual devices can are torque-controlled electric motors, and in the exemplary embodiment, the motors are servomotors.  
           [0023]    The adjustment operations can occur simultaneously with other controlled resetting operations and/or adjustments. Adjustments can occur during the operation of the wire-stitching unit and/or a gathering and wire-stitching apparatus, or can take place either before or after a wire-stitching cycle.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    The invention is explained in the following with the aid of an exemplary embodiment and with reference to the drawings, to which we refer for all details not mentioned in the specification.  
         [0025]    [0025]FIG. 1 shows a wire-stitching unit of a gathering and wire-stitching apparatus.  
         [0026]    [0026]FIG. 2 shows another view of the stitching unit shown in FIG. 1.  
         [0027]    [0027]FIG. 3 shows a rear view of the stitching unit shown in FIG. 2.  
         [0028]    [0028]FIG. 4 shows a side view of a stitching aggregate for the stitching unit.  
         [0029]    [0029]FIG. 5 shows a wire stitching staple.  
         [0030]    [0030]FIG. 6 shows a rear view of the stitching aggregate.  
         [0031]    [0031]FIG. 7 shows a front view of the stitching aggregate.  
         [0032]    [0032]FIG. 8 shows a sectional view through the stitching carriage along the line VIII-VIII of FIG. 10.  
         [0033]    [0033]FIG. 9 shows a view of the drive unit for the bending device.  
         [0034]    [0034]FIG. 10 shows a sectional view through the bending device along the line X-X of FIG. 8.  
         [0035]    [0035]FIG. 11 shows an alternate embodiment of the wire stitching unit.  
         [0036]    [0036]FIG. 12 shows an enlarged view of a detail showing the adjustment mechanism according to FIG. 11.  
         [0037]    [0037]FIG. 13 shows a drive unit for adjusting the height of the conveying arrangement. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]    Referring to the Figures, a gathering and wire-stitching apparatus includes a stitching unit  1  arranged on a conveying arrangement  2 . Individual printed products or products gathered to form printed products  5  are positioned straddling on carriages  4  attached to a traction mechanism with saddle-shaped supports  3 . The printed products  5  are conveyed on a conveying arrangement  2  in a conveying direction F to the stitching unit  1  traveling along with the conveying arrangement to stitch the printed products  5  along the fold. The stitching unit  1  includes two stitching aggregates  6 ,  7  and respectively one bending block  8 ,  9  of a bending device  10 . The stitching aggregates  6 ,  7  and the bending device  10  are arranged on a stitching carriage  11  driven back and forth along the conveying device  2 . The stitching unit  1  and conveying arrangement operate synchronously in the gathering and wire-stitching apparatus. The stitching carriage  11  is guided along two rods  13 ,  14  connected to a machine frame  12 .  
         [0039]    The operation of the stitching aggregates  6 ,  7  is described in Swiss Patent Document A-549 443, incorporated herein by reference, and is explained further herein within the framework of the present invention. Stitching wire  15  is fed to the stitching aggregates  6 ,  7  while clamped between two friction wheels  16 ,  17 , via a wire guide  18 , at a wire length that corresponds to the desired size of the wire staple. The friction wheels  16 ,  17  are driven by two gear wheels  19 ,  20  that mesh and are fixedly connected to the friction wheels  16 ,  17 , as particularly shown in FIG. 7.  
         [0040]    A locally fixed, torque-controlled electric motor  21  varies the length of the wire segments for the staples. A finished staple is shown in FIG. 5. The electric motor  21  is coupled to at least one of the friction wheels  19 ,  20  and also to a control unit  22 . This arrangement prevents wear and tear to the cables supplying energy to the electric motor  21 , usually caused by the stitching unit  1  movements, due to the structural design of the stitching carriage  11  and the adjustment mechanism. The electric motor  21  can be connected to the machine frame  12 , and a drive shaft  30  of the electric motor extends through the carriage  11  parallel to its movement direction and is provided with respectively one miter wheel  24   25  allocated to each stitching unit  6 ,  7 , to form a miter gear unit  28 ,  29  together with a miter wheel  26 ,  27 . The driving miter wheel  26 ,  27  is respectively located on the shaft  30  of the friction wheel  17 , as particularly shown in FIG. 3. The shaft  30 , for example a spline shaft or polygonal shaft, has a form-fitting cross section to drive the miter wheels  24 ,  25 . The shaft  30  is supported inside bearing blocks  31 ,  32  of the stitching aggregates  6 ,  7  fixedly connected to the stitching carriage  11 , and the miter wheels  24 ,  25  are positioned on roller bearings in the bearing blocks  31 ,  32 . The stitching carriage  11  has two side walls, and the shaft  30  extends with at least some play through the wall facing the electric motor  21 . Alternatively, the bearing blocks  31 ,  32  can also be attached to the stitching carriage  11 .  
         [0041]    The wire feed supplies a wire segment to form a symmetrical staple  33 , as shown in FIG. 5. The wire segment for the staple  33  is supplied to the bender  35  and the driver  36 , which together form the stitching head  34 . A wire-cutting device  38  is arranged upsteam of the stitching head  34  relative to the feed of the wire. The wire segment to be shaped into a staple  33  is positioned evenly spread out over the bender  35  such that a staple  33  with identically long legs  39  is formed. Owing to possible different sizes for the staple  33 , the wire-cutting device  38  can be adapted to various staple sizes such that the wire section comes to rest evenly distributed relative to the bender. A movable gripper or clamp  40  on the stitching head  34  of the stitching aggregate  6 ,  7  holds the wire segment in place and positions the wire segment for bending. The wire cutting device  38  includes a blade holder  41  with wire lead-through  42  provided on its rear side with a blade  43  that is drive-connected to the pullback movement of the driver  36 . The blade  43  cuts the wire section with the aid of the wire lead-through  42  acting as a counter blade.  
         [0042]    To ensure an evenly positioned wire segment for the stitching head  34 , the blade holder  41  is displaced corresponding to the advancing and/or following wire end in such a way that the wire section, which is gripped by the gripper  40  following the cutting by the blade  43 , assumes the stitching position in the stitching head. When cutting staples of different wire lengths, the blade holder  41  includes an upwardly slanted guide track  44  into which a follower pin  45 , attached to a slider  46 , engages. As particularly shown in FIGS. 4 and 7, the blade holder  41  is in the position for the shortest wire sections. The slider  46 , in turn, is a plate and is guided on all sides. The slider  46  has a drive cam  47  on the rear side that engages a cam rail  48  which connects the sliders  46  of the blade holders  41 . Arms  49  form the ends of the cam rail  48  and have freely rotating guide rollers  50  on the exposed ends which project into a slit-type guide member  51  on a guide rail  52 . The guide rail  52  extends below the stitching aggregates  6 ,  7 , and the length of guide member  51  equals at least the length of the path for stitching carriage  11 . The guide rail  52  is attached at each end to respectively one support  53  having an inside thread for receiving a thread spindle  54 . The thread spindles  54 , which are provided for adjusting the height of guide rails  52 , are positioned in a bearing block  55  attached to a machine frame  12  and are drive-connected to a locally fixed electric motor  56 . Depending on the thickness of the printed products  5  to be stitched, the blade holders  41  of the stitching aggregates  6 ,  7  are adjusted and/or adapted  5  with the aid of the electric motors  56  and the control unit  22 . The height of guide rail  52  is adjusted either before or after the stitching of a printed product without leading to a delay in machine timing. Reference numeral  5 ′ in FIG. 1 refers to a stitched printed product which is subsequently removed from the support  3 .  
         [0043]    In an alternative design of the adjustment mechanism for the blade holder  41 , the follower pin  45  that engages in an upwardly slanted guide track  44  is drive-connected via a lever arrangement  94  to a locally fixed electric motor  57  (see FIGS. 12 and 13). The drive shaft  58  of the lever arrangement  94 , in turn, can have a form-fitting design and respectively one single-arm lever  59  can be secured thereon so as to be displaceable at the end of stitching carriage  11 . A guide rod  60  is connected at one end to the single-arm lever  59  and to a cam rail  48  at the other end, as particularly shown in FIG. 11. The cam rail  48  is arranged to be height-adjustable inside a guide mechanism  93 .  
         [0044]    [0044]FIGS. 2, 8,  9  and  10  show the adjustment mechanism for the bending device  10  arranged on the carriage  11 . The bending device  10  includes two bending blocks  8 ,  9 , which can be jointly adjusted and height adapted according to different thicknesses of the printed products  5 . The adjustment mechanism for the bending device  10  includes a bending support  61 . The bending support  61  can be guided while positioned vertically on a wedge  62  attached to the stitching carriage  11  and is held on the carriage  11  with screws  63  that respectively extend through a vertical slot.  
         [0045]    As particularly shown in FIGS. 8 and 10, the height of bending blocks  8 ,  9  is adjusted with an torque-controlled electric motor  64  locally fixed to the machine frame  12 . The electric motor  64  includes a drive shaft  65  having a width approximately corresponding to the width of the stitching carriage  11 . The drive shaft  65  is positioned inside the stitching carriage  11  on two spaced-apart stiffening ribs  66 . A torque-transferring ball sleeve  67  is positioned between the stiffening ribs  66  and is designed as a torque-transmitting and displaceable shaft-hub connection to transmit the rotational movement of the drive shaft  65  to a bushing  68  that is positioned on the drive shaft  65  and moving along with the stitching carriage  11 . The bushing  68  and the drive shaft  65  are positioned jointly with ball bearings in the stiffening ribs  66 . Respectively one clamping lever  69  is attached to the ends of the bushing  66 . The clamping lever  69 , which can be pivoted with the aid of the electric motor  64  and the drive shaft  65 , is connected with a rod  70  to a toothed segment  72  positioned on a parallel shaft  71 . The toothed segment  72  meshes with a gear rod  73  attached to the stitching carriage  11 . As a result of the movements of drive shaft  65  and the shaft  71  connected via bearing blocks  74  to the bending support  61 , the bending support  61  is lowered or raised to a desired level, which corresponds approximately to the difference in thickness between two printed products  5 .  
         [0046]    The wings on the head of the bending blocks  8 ,  9  which form the closed staple are operated with a control curve  75 , along which a pivoting lever  76  positioned on a shaft  71 , as a result of the stitching carriage movement, are pivoted counter to the spring force that activates tappets  78  guided on both sides of the carriage  11  with a control roller  77 . The tappets  78  are connected via levers  79  to the shaft  71 .  
         [0047]    [0047]FIGS. 11 and 13 particularly illustrate that the conveying arrangement  2  can be adjusted in height with the bending device  10 . An additional clamping lever  80  is provided on the shaft  65  on both sides of the stitching carriage  11 . The conveying arrangement  2  includes a chain guide  81 , across which two circulating link chains  82  are guided. Individual members  83  are fitted onto the chains  82  to form a roof-shaped support  3 . FIGS. 11 and 13 show individual members  83  that are inclined only to one side. At the upper end of the support  3 , the individual members  83  form a gap through which the bending blocks  8 ,  9  are lifted. In conveying direction F of the printed products  5 , guide elements  84  that guide the printed products  5  onto the bending blocks  8 ,  9  are arranged in front of the bending blocks and are connected so as to be adjustable along with the bending blocks. The height of the conveying arrangement  2  is adjusted with a lever gear  85 , which acts from below upon the chain guide  81 . Two lifters  86  are connected at a distance to each other to the chain guide  81  and extend in a downward direction. The lifters  86  are positioned with a roller  87  on a first lever arm  88  of an angled double lever  89 . The second lever arm  90 , at an angle of approximately 90°, is connected at an exposed end via a guide rod  91  to the clamping lever  80 . The lifters  86  are guided inside a frame  92  fixedly connected to the machine frame  12 .  
         [0048]    The invention has been described in detail with respect to preferred embodiments, and it is will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departed from 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.
A wire-stitching apparatus for producing wire-stitched print items includes a conveying arrangement for supplying folded, printed products in a straddling position; a wire-stitching unit installed at an adjustable distance above the conveying arrangement and including a bending device; at least one wire-stitching aggregate; and a stitching carriage for moving the at least one wire-stitching aggregate back and forth along a path. The wire-stitching aggregate includes a bender for forming legs of a staple and a driver for pushing the staple legs through the printed products. At least one wire feed feeds wire to the one wire-stitching aggregate at a stitching wire length. At least one adjustable wire-cutting device for adapts a wire staple to the thickness of the printed products. A control unit measures the thickness of the printed products positioned on the conveying arrangement upstream of the wire-stitching unit, and/or processes stored data related to the printed products.