Patent Document

BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a device for removing printed products transported uniformly spaced and astraddle on a transport device, wherein the device comprises a rotatingly driven gripping device with controlled gripping elements which grip a printed product on the transport device in the area of folding and remove it while maintaining it in a stable position.  
           [0003]    2. Description of the Related Art  
           [0004]    A device of the aforementioned kind is known in the prior art, for example, in EP 0 771 675 A1, assigned to the instant assignee. This device has a clamping device which describes a circular travel path and picks up a single printed product while being transported and removes it in a position-stable fashion from a conveying chain and supplies it to a further processing device. This device is used, in particular, for gather-stitcher devices and has been proven successful in practice. Such devices are also referred to as deliveries. A further device of this kind is known from U.S. Pat. No. 4,482,141.  
           [0005]    In the known device it is important that the printed products while being transported are safely gripped by the grippers and are removed from the transport device in a position-stable way. The printed products to be removed can be of very different thickness.  
           [0006]    Printed products are known which are comprised only of a thin sheet and which are very lightweight and unstable. On the other hand, very thick, and correspondingly heavy, printed products must be processed. For a high transport output, in particular, in the case of very thin as well as very thick products disruptions can occur which can be avoided only with very complicated adjusting processes.  
         SUMMARY OF THE INVENTION  
         [0007]    It is an object of the invention to provide a device of the aforementioned kind such that printed products having very different thicknesses can be processed safer, faster and with less adjusting work.  
           [0008]    In accordance with the present invention, this is achieved in that the control means, which are provided for the closing movement and/or opening movement of the gripping means, are adjustable during operation for adaptation to the thickness of the printed products.  
           [0009]    According to the invention, control means are provided for the movement of the gripping means which control means, for adjustment to the thickness of the printed products, can be readjusted during operation or running. By adjusting the control means it is possible to adjust the clamping force of the gripping means precisely to the thickness of the printed product being transported. Preferably, for this purpose the thickness of the printed product is measured by means of a measuring device. Based on the measured thickness, the closing movement of the gripping means is controlled such that the printed products are gripped with optimal clamping force. Since the movement can be readjusted during operation, a readjustment is thus possible, even at high conveying output, so that printed products of very different thicknesses can be successively processed without any interruption. For each gripping cycle, the closing movement can be adjusted by readjusting precisely to the thickness of the printed product. For example, printed products of a thickness of, for example, 1 mm, and, subsequently, one of a thickness of 20 mm, can be gripped with an optimal clamping force, respectively.  
           [0010]    It was found that the control means can be adjusted very quickly with mechanical means, for example, within 100 milliseconds.  
           [0011]    According to a further embodiment of the invention, two grippers are controlled by means of a lever which has a roller that is pressed against a control curve of a curve ring. By means of a control disc, this curve ring is moved during operation horizontally such that the position of the aforementioned control curve is changed. The movement of this curve ring is carried out preferably by means of a further control disc which also has a control curve and is adjustable during operation on curve levers fixedly mounted on the frame.  
           [0012]    The adjustment is carried out according to a further embodiment of the invention preferably by means of two curve levers which, for example, are pivotable by means of a pneumatic drive. Such a pivoting action can be very quickly and very precisely performed based on a signal which corresponds, for example, to a thickness measurement carried out by means of a sensor. In principle, the readjustment causes a radial rotational movement of a control disc to be transformed into an axial movement of a curve ring.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0013]    In the drawing:  
         [0014]    [0014]FIG. 1 is a view of the device according to the invention;  
         [0015]    [0015]FIG. 2 is a partial view of the device according to the invention of FIG. 1;  
         [0016]    [0016]FIG. 3 is a perspective view of the portion of the device illustrated in FIG. 2;  
         [0017]    [0017]FIG. 4 is an end view of the gripping device;  
         [0018]    [0018]FIG. 5 is a section along the line V-V of FIG. 2;  
         [0019]    [0019]FIG. 6 is a vertical section of the gripping device according to FIGS. 2 and 3;  
         [0020]    [0020]FIG. 7 is a partial view of the device according to the invention; and  
         [0021]    [0021]FIGS. 8 a  to  8   c  illustrate schematically the gripping of printed products by means of a gripper.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]    The device  1  illustrated in FIG. 1 has a plate  18  which is connected to a frame  71  and on which a gripping device  66  is supported in a rotatable fashion. The gripping device  66  is driven, for example, by means of a drive belt  72  in the direction of the arrows  21  about a horizontal drive axis A. The gripping device  66  has a support  70  which is comprised essentially of a hexagonal flange  19  as well as two bearing plates  23 . Each bearing plate  23  is formed as a gripper arm  67 ,  68 . It is also possible to connect, as desired, three gripper arms to the hexagonal flange  19  such that between adjacent gripper arms an angle of 120° is formed, respectively. In principle, an embodiment with only one gripper arm or more than three gripper arms is also conceivable.  
         [0023]    Each gripper arm  67 ,  68  has two grippers  24  with which a printed product  4  of a collecting chain  3  or a similar transport device is gripped and then transferred in a stable position to a further conveying member  17 . The conveying member  17 , which is only schematically illustrated, is, for example, a wheel which grips a printed product  4 ′ by, for example, a clamping device, not illustrated, and transports the printed product farther downstream.  
         [0024]    The collecting chain  3  has a flexible endless chain  2  which has uniformly spaced drivers  5  with which the printed products  4  are transported in a straddling position in a manner known in the art. In FIG. 1, the arrow  12  indicates the running direction of the chain  2 . Only portions of the chain  2  are shown. In order for the printed products  4  to be gripped by their fold  4   a , a so-called sword (blade)  13  is provided onto which the printed products  4  are slipped in the direction of arrow  11 . This sword or blade  13  has at its upper side two cutouts  14  directly adjacent to one another. When one of the printed products  4  is positioned in these cutouts  14 , it is gripped with two grippers  24  and, as a result of the rotating movement of the gripping device  66 , is moved upwardly and transferred onto the conveying member  17 . The transfer occurs when the grippers  24  open and release the printed products  4 ′.  
         [0025]    For securing the printed products, each gripper  24  has a forward free end with a clamping jaw  73  which, according to FIG. 8 a , can be moved toward one another in the direction of arrow  74  for securing the printed products  4 . The two gripper arms  67 ,  68  have two grippers  24 , respectively, as illustrated in FIG. 1. The two grippers  24  of a gripper arm  67 ,  68  are rotatable about a horizontal axis B, respectively, and, when rotating the carrier  70 , are rotated about the axis B in the counter direction such that the grippers  24  are always aligned vertically according to FIG. 1. The clamping jaws  73  of a gripper pair  24  are thus positioned always on a horizontal line and are thus always at a same spacing to the fold  4   a  of the printed products  4  to be gripped.  
         [0026]    In order for the aforementioned alignment of the grippers  24  to be ensured, an intermediate gear  26  is rotatably supported on each one of the bearing plates  23 . According to FIG. 2, gear  26  meshes with a central gear  28  as well as an outer gear  27 . The central gear  28  is arranged coaxially to the drive axis A and fixedly connected to the bearing plate  18 . In FIG. 1, the central gear  28  is positioned behind the flange  19  and is thus not visible. When the gripping device  66  in FIG. 1 is driven according to the arrows  21  in a counterclockwise direction, the intermediate wheels  26  are forcibly rotated in the counterclockwise direction, as illustrated in FIG. 2 by arrow  29 . The outer wheels  27  rotate, on the other hand, in the clockwise direction, as indicated in FIG. 2 by arrow  30 . According to FIG. 6, the gears  27  are fixedly connected by means of a hollow shaft  61 , respectively, to two bearing plates  38 . The bearing plates  38  are arranged at a spacing to one another and, according to FIG. 2, an upper shaft  33  and a lower shaft  34  are supported on the bearing plates  38 . The hollow shafts  61  penetrate each one of the two bearing plates  23  and are rotatably supported therein by means of a bearing  53 ; see FIG. 6.  
         [0027]    The rotational movements of the gears  27  are thus transmitted respectively by the hollow shaft  61  onto the two bearing plates  38 . The gears  26 ,  27 , and  28  are formed such that the hollow shafts  61  are rotated relative to the bearing plates  23  such that the two bearing plates  38  are always aligned according to FIG. 1 in a vertical position.  
         [0028]    As mentioned above, on the bearing plates  38  an upper shaft  33  and a lower shaft  34  are rotatably supported. On the upper shaft  33  two upper gripping arms  24   a  are fastened at a spacing to one another. For their attachment, a clamping part  35  is mounted on the gripping arms  24   a , respectively. On the upper shaft  33 , a gear segment  36  is fixedly connected which is arranged between the two bearing plates  38  and meshes with a gear  37  which is fixedly connected to the lower shaft  34 . The two axles  33  and  34  are thus in interactive connection by means of the meshing gear segment  36  and gear wheel  37 . When rotating the shaft  34 , the upper shaft  33  thus rotates in the opposite direction. On the lower gear  37 , according to FIG. 6, a radially projecting bolt  44  is fastened on which a tensioned coil spring  42  engages. This spring  42  according to FIG. 6 is fastened with one end to the bolt  43  and penetrates the hollow shaft  61 . The tension of the spring  42  causes a torque in the counterclockwise direction on the gear  37  shown in FIG. 6. This torque is illustrated in FIG. 6 by means of the arrow  75 . This torque is exerted onto the lower shaft  34  which, as mentioned above, is rotationally fixedly connected with the upper shaft  33 . On the lower shaft  34 , according to FIG. 2, a pivot lever  41  is fixedly connected on which two rollers  40  are supported. As a result of the aforementioned torque, these two rollers  40  are now pressed against an opening ring  52  or a closing ring  51 . These two rings  51  and  52  have, according to FIG. 6, a control curve  51   a  and  52   a , respectively. By means of these control curves  51   a  and  52   a , the pivot lever  41  is pivoted against the return force of the spring  42  about the axis of the shaft  34 . This pivot movement is transmitted onto the gear  37  and onto the gear segment  36 . Accordingly, the gripping arms  24   a  and  24   b  are pivoted for opening and closing the corresponding gripper  24 . The pivoting of the gripping arms  24   a  and  24   b  is carried out simultaneously and with oppositely oriented pivot movements. This is the result of the engagement of the gear  37  with the gear segment  36 . The clamping jaws  73  thus simultaneously move away from one another or, according to FIG. 8 a , move toward one another for gripping a printed product  4 .  
         [0029]    The opening ring  52  and the closing ring  51  according to FIGS. 5 and 6 are arranged on a flange  50  which is supported so as to be axially or horizontally slidable on a bearing sleeve  54 , as illustrated in FIG. 6 by the double arrow  76 . For moving this flange  50 , a control disc  46  is rotatably supported thereon which at its end face has a curved surface  46   a  which cooperates with a curve  60   a  of a further control disc  60 , as illustrated in FIG. 5. Upon rotation of the control disc  46 , the curved disc  60  and thus the flange  50  are axially moved in the direction of double arrow  76 .  
         [0030]    For rotating the control disc  46 , a radially projecting stay  47  is fastened thereto and has connected thereto a roller holder  48 . A roller  49  is supported on this roller holder  48  and rolls on a convex curve  64   a  of a curve lever  64  or on a concave curve  63   a  of a curve lever  63  when the support  70  is rotating. These two curve levers  63  and  64  are supported on the bearing plate  18  with their upper end so as to be pivotable about a rotational axle  65 . For pivoting the levers  64  and  63 , they are connected with their lower ends to the drive plate  10  which, according to FIG. 1, is pivotal in the direction of double arrow  9  by means of the drive  8 . The two levers  63  and  64  are thus pivoted together about the axes  65 . The drive  8  is, for example, a pneumatic drive. However, conceivable is also another drive, for example, an electric drive with an electric motor. Depending on the position of the drive plate  10 , the roller  49  runs on the curve  64   a  or the curve  63   a . By means of the curve  64   a , the control disc  46  can be rotated in the counterclockwise direction. By means of the curve  63   a , on the other hand, the control disc  46  can be rotated in the clockwise direction. The two curves  63   a ,  64   a  thus form a through channel.  
         [0031]    These rotational movements are always carried out when the two grippers  24  are in the position illustrated in FIG. 1. In this position, the grippers  24  are open, as illustrated in FIG. 8 a . After this position, i.e., after the roller  49  has passed along the two curve levers  63  and  64 , the corresponding grippers  24  are closed when reaching the two cutouts  14 . Since, as has been mentioned above, the opening is realized by rolling of the outer one of the two rollers  40  on the opening ring  52 , the axial position of this opening ring  52  affects the opening width of the corresponding grippers  24 . When the opening ring  52  in FIG. 6 is positioned comparatively far to the left, the two paired grippers  24  are opened by a comparatively small angle. When the opening ring  52 , on the other hand, is positioned farther to the right in FIG. 6, the two grippers  24  are opened with a greater angle. The closing movement, on the other hand, is affected by the axial position of the closing ring  51 . During clamping, the gripping arms  24   a ,  24   b  are tensioned against the pretensioned disc spring  32 . When surpassing a predetermined clamping force, the gripping arms  24   a ,  24   b  are pivoted relative to the clamping parts  35  and  35   a  and the disc springs are compressed.  
         [0032]    The FIGS. 8 a  to  8   c  show schematically the clamping of printed products  4 ,  4 ′, 4 ″ of different thickness. For gripping, the gripping arms  24   a ,  24   b  according to FIG. 8 a  are pivoted relative to one another in the directions of arrows  74 . This closing movement is controlled by the closing ring  51  or the control curve  51   a  on which the outer one of the two rollers  40  is running. In order to engage the comparatively thin printed product  4 ′ with a suitable pressing force, the two gripping arms  24   a ,  24   b  are moved to a comparatively short spacing C, as illustrated in FIG. 8 b . In order to achieve this, the closing ring  51  in FIG. 6 is moved comparatively far to the left and the spring  42  is comparatively strongly tensioned. In order to grip a comparatively thick product  4 ″, the two gripping arms  24   a ,  24   b  according to FIG. 8 c  are moved to a correspondingly greater spacing C′. Between the spacings C and C′ all intermediate spacings can be adjusted in a continuous fashion. As a result of the positioning of the curve  52   a  not only the clamping force is controlled but also the speed with which the grippers  24  close and open. The printed products  4  to  4 ″ can thus be gripped with the optimal clamping force, respectively, and can also be gripped or released at a suitable point in time. This allows handling of a large thickness range D, as is illustrated in FIGS. 8 b  and  8   c . Since, as mentioned above, the opening ring  52  and the closing ring  51  can be positioned for each pass by the two control levers  63  and  64 , it is possible for directly following printed products  4  to have very different thicknesses. The opening parameter C, respectively, the clamping force is adjusted in any situation in an optimal way. Since the adjustment is mechanical and forced, a very quick readjustment is possible, for example, within 100 milliseconds or less. The readjustment is carried out as a result of a thickness measurement by means of a measuring device  6  which according to FIG. 1 is positioned upstream of the blade  13  and which has, for example, a sensor. The measured value is transmitted to the control  7  which controls correspondingly the drive  8 .  
         [0033]    The device  1  according to the invention is preferably a so-called delivery for a gather-stitcher device; however, other applications are also conceivable in which printed products must be gripped while being transported and transferred in a stable position to a further device.  
         [0034]    In the following, a working cycle is explained in more detail.  
         [0035]    In one working cycle the gripping device  66  is rotated about the drive axis A by 360°. This rotational movement is synchronized with the running of the chain  2 . The axes B during such a cycle describe, respectively, a circle whose center is the drive axis A. With two gripper arms  67 ,  68  according to the embodiment shown in FIG. 1 two printed products  4  are gripped and lifted off the blade  13  and then transferred onto a further device  17  during such a working cycle.  
         [0036]    The gripping of a printed product is carried out according to FIG. 1 approximately at the 6 o&#39;clock position. The printed product is released shortly thereafter approximately in the three o&#39;clock position. Between these two positions the opening ring  52  is thus active. The adjustment of the opening ring  52  and of the closing ring  51  is realized in the area of the curves  63   a  and  64   a  and thus approximately in the 9 o&#39;clock position. Subsequently, the closing ring  51  becomes active and closes the grippers  24  as soon as they have reached the cutouts  14  of the blade  13 .  
         [0037]    The curve levers  63  and  64  are adjusted only when a printed product  4  is detected by the measuring device  6  that has a thickness different from that of the preceding printed product. The adjustment is carried out at the latest when the roller  49  is positioned between the two curve levers  63  and  64 .  
         [0038]    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.

Technology Category: 7