Abstract:
The extension arm is used for removing printed products, which are conveyed with the aid of circulating carriers, such that they straddle a saddle-shaped support of a conveying arrangement. With the aid of a gripping device, the printed products are gripped and then lifted off the conveying arrangement. The gripping device comprises two rotating gripping members, which are respectively positioned on the circumference of an also rotating support and between which the printed products are gripped and removed. The gripping members preferably have a curved outer shell surface that forms an essentially circular contour together with an outer shell surface of a support. The printed products can be pulled off in horizontal direction and with initially high speed from the conveying arrangement and can then be transferred with a vertical movement to another conveying arrangement. Thus, a collision with the subsequent printed product can be avoided even with a high production capacity.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application claims the priority of European Patent Application No. 01810809.2 filed on Aug. 21, 2001, the disclosure of which is being incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    The invention relates to an extension arm for removing folded printed products, which are transported straddling with the aid of circulating carriers on the saddle-shaped support of a conveying arrangement. The extension arm is provided with a gripping device for gripping the printed products, such that they can be transported away with the conveying arrangement.  
           [0003]    Extension arms of the aforementioned type have long been known in the print-processing industry and, in particular, are used to carefully lift off printed products such as brochures, newspapers and the like from a gathering section moving in longitudinal direction. The printed products lifted off the gathering section are deflected and are supplied, for example, to a device for trimming the top, bottom and front.  
           [0004]    In particular, the gathering section has an endless gathering chain on which feeders deposit printed sheets that are removed from a stack for forming the printed products. Carriers are arranged evenly spaced along the gathering chain and are used to transport the folded printed sheets deposited on the chain. The carriers can be attached to the gathering chain, such that they can be adjusted for changing the spacing. For the so-called “selective binding,” the printed products are selectively assembled and the thickness of the printed products can be changed in this way. The assembled printed products as a rule are bound, in particular in the region of the gathering chain, with the aid of a wire-stitching machine. In that case, the gathering chain is preferably a double-gathering chain.  
           [0005]    In the high-performance range, the production speed is frequently limited by the capacity of the extension arm, which must lift and deflect the printed products carefully and, at the same time, without interruption. Further, the separate printed products must be lifted off the conveying track at a high enough speed, so that the following printed product does not collide with the previous one. In addition, the printed products must be gripped and lifted off with enough care, so that the printed products are not damaged and, in particular, no markings are created on the outside. For the “selective binding,” it should furthermore be possible to remove printed products of different thickness and different formats with the same high capacity.  
           [0006]    Swiss Patent No. CH-A-358 100 discloses an extension arm, which lifts up the printed products with a sword and then inserts the printed products between successively arranged roller pairs. The rotational axes of the respective roller pairs are directed parallel to the movement plane of the sword and perpendicular to its slanted movement components. The slanted orientation of the sword movement and the roller pairs, as well as a drive connection of the sword are dimensioned such that the printed products retain their horizontal conveying speed when they are lifted off. The printed products are deflected relatively sudden and without particular care with respect to the product. The production speed of the system is limited to 8,000 to 10,000 copies per hour, depending on the chain division and format.  
           [0007]    A different extension arm is known from Swiss Patent No. CH-A-525 142, which is designed to permit a further increase in the speed. A lift-off sword is provided for this, which is moved along an elliptical path in such a way that the movement component above the chain apparatus is always oriented in advancing direction.  
           [0008]    European Patent No. EP 1 072 546 A1 discloses an apparatus, comprising a star-shaped, rotatingly driven device, for removing the printed products above the gathering chain with the aid of tongue-like gripping members that lift the printed products from the gathering chain quickly and in the most stable position possible. The products are gripped by the tongue-shaped clamping members of a stationary sword and pulled in a 90° curve onto vertically moving belts. The rotating gripping members grip the printed products with a speed that is slightly higher than the transporting speed of the gathering chain. As a result, the printed products are pulled somewhat away from the carriers and thus do not hinder the outgoing printed product. A production speed of 20,000 to 25,000 copies per hour can be achieved, depending on the chain division and the number of rotating gripping members. The disadvantage of this arrangement is the comparatively large space required for the rotating gripping members and the high gripping forces necessary for controlling the acceleration and delay forces that occur during the deflection of the printed products. In addition, difficulties can arise during the processing of individual sheets in the case of a malfunction. In that case, the gripping members must automatically adjust to the thickness of such an individual sheet during the operation, which is very involved from a design point of view. During the individual readjustment from 21″ to 14″, the number of gripping arms must furthermore be increased from two to three.  
         SUMMARY OF THE INVENTION  
         [0009]    It is the object of the present invention to develop an extension arm for removing folded printed products from a support, which permits an even higher production speed while still operating carefully and in a safe manner. In addition, it should have a compact design.  
           [0010]    This object is solved with an extension arm having a gripping device for picking up and transporting off printed products in that the gripping device is provided with at least two rotating gripping members. The rotating gripping members are respectively positioned along the circumference of a rotating carrier between which the printed products are gripped and lifted off. The printed products are gripped by the rotating gripping members, which may be respectively positioned on the rotating carrier. As a result, the movement of the printed products is not limited to a circular path or a linear path, and thus, the movement of the printed products may have an optimum design. In particular, the movement path can be designed such that the collision with a following printed product associated with known extension arms at higher production speeds is avoided. According to the invention, a speed can be achieved at which the printed products are taken over virtually without impact by the gripping members, thus assuring a careful handling of the printed products. Furthermore, the printed products may be transferred to an additional conveying arrangement, for example onto belts, with a very small impact. Since rotating arms are not required according to the invention, a particularly compact design of the extension arm and gripping members may be obtained.  
           [0011]    If, according to another modification of the invention, the gripping members have a beehive design, a particularly high production speed with careful handling of the printed products may be achieved. The largest diameter for the beehive-shaped gripping members is preferably dimensioned such that the resulting circumferential speed per cycle is higher than the chain division of the conveying arrangement. As a result of the somewhat higher, horizontal maximum circumferential speed of the beehive-shaped gripping members, as compared to the speed of the conveying arrangement, the printed product can be withdrawn optimally from the carriers. The beehive-shaped gripping members are preferably arranged in such a way that the printed products are displaced in the direction of the decreasing diameter during the carrier rotation. The printed products are consequently braked continuously in a horizontal direction and are transferred with a minimum horizontal speed to the conveying arrangement that is positioned at a right angle thereto.  
           [0012]    Other advantageous features follow from the dependent patent claims, the subsequent description and the drawing.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    An exemplary embodiment of the invention is explained in further detail in the following with the aid of the drawings in which:  
         [0014]    [0014]FIG. 1 schematically illustrates a vertical section through an extension arm according to the invention, as well as a portion of a conveying arrangement;  
         [0015]    [0015]FIG. 2 is a schematic view from above of the extension arm according to the invention;  
         [0016]    [0016]FIG. 3 is a schematic section through the extension arm and the conveying arrangement along the line III-III in FIG. 2; and  
         [0017]    [0017]FIG. 4 is a section corresponding to FIG. 3, but showing a later operational state. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    The extension arm  1  is arranged in the region of a conveying arrangement  8 , which conveys printed products  5  with a gathering chain  2  in the direction of arrow  6 , as shown in FIG. 1. FIG. 3 shows that a double gathering chain comprising two individual chains  3  and  4  and a saddle-shaped support  43 , on which the printed products  5  are conveyed straddling. In the process, the printed products  5  are carried along with the aid of carriers  7  that project on the side of gathering chain  2  or double chain  3 ,  4 . The carriers  7  can be adjusted advantageously for changing the chain division. The printed products  5  as a rule include several printed sheets, which are dropped onto the gathering chain  2  or double chain  3 ,  4  via feeders, not shown herein. The folded printed sheets, used to form the printed products  5 , can be opened up inside these feeders and deposited onto the gathering chain  2 . The printed products  5 , created with these sheets, therefore have respectively one fold  5   a  that extends in conveying direction of the gathering chain  2  or double chain  3 ,  4  during the transport of the product. The printed products  5  are transported straddling at an acute angle, which conforms to the saddle-shaped support  43 . The printed products  5  can also be individual folded sheets.  
         [0019]    A lift-off sword  34  is provided to convey the printed products  5  into the region where they are gripped by a gripping device  100  of extension arm  1 . The sword is arranged between the two gathering chains  3  and  4 , as shown in FIG. 3. FIG. 1 shows that the sword has a comb-like upper edge  44 . The lift-off sword  34  is connected to and operated with two crank disks  35 , such that it moves along a closed, circular or oval curved path in a vertical plane and, during each circulation, lifts a printed product  5  from the gathering chain  2  or double gathering chain  3 ,  4  and moves it into the pick-up range of the extension arm  1 . The two crank disks  35  are positioned rotating on two shafts  37 , wherein one of these shafts is a drive shaft and the two crank disks  35  are respectively connected to each other with an endless toothed belt or chain  36 . The bearing arrangement  38  serves to position the lift-off sword  34  on the two crank disks  35 , as shown in FIG. 3. Naturally, the movement of lift-off sword  34  is synchronized with the movement of the conveying arrangement  8 . The lift-off sword  34  can also be stationary, wherein the printed products  5  are pushed onto the lift-off sword  34  and the gathering chain  2  is lowered, in a manner as known per se.  
         [0020]    The extension arm  1  is provided with two bearing plates  9  and  10 , on which two parallel extending drive shafts  14  are positioned at a distance to each other. FIG. 2 shows that the drive shafts  14  are rotationally connected to respectively one drive wheel  11 , around which an endless toothed belt  12  is fitted. Three disk-shaped supports or carriers  15  are mounted on each drive shaft  14 , so as to rotate along, which are arranged in pairs and at a distance to each other as shown. Also conceivable is a design with less than three or more than three supports  15  for each shaft  14 . The supports  15  are driven such that they rotate in the counterclockwise direction, as shown in FIG. 4. The left supports  15  in FIG. 4 are driven in the counterclockwise direction, as shown with arrow  55 , and the supports  15  on the right side are driven in the clockwise direction according to arrow  56 . The rotational speeds and the circumferential speeds of supports  15  are respectively the same.  
         [0021]    Gripping device  100  is described with reference to FIGS. 3 and 4. Two beehive-type rollers are positioned on each support or carrier  15 , which are arranged diametrical to the respective drive shaft  14 , as can be seen in FIGS. 3 and 4, and which form the gripping members  20 . The rollers or gripping members  20  are respectively positioned on a shaft  24  that is attached with a holder  25  to the support  15 . As shown, the supports  15  are respectively provided with a bearing  23 , which holds one shaft  24 . The shafts  24  extend respectively crosswise to the drive shafts  14 .  
         [0022]    The rollers or gripping members  20  are respectively driven with a bevel-gear drive  42 , which comprises a wheel  27  that is rotationally connected to the shaft  24  and meshes with a wheel  17 , which is mounted on a drive shaft  16 . FIG. 2 shows that each drive shaft  16  is positioned rotating on two disks  46  and  47 , which are respectively connected fixedly to one of the drive shafts  14 . A spur gear  18  (sun gear) is attached centric to the drive shaft  14  and is fixedly connected to the side plate  10 . Two planetary gears  19 , arranged diametrically opposite each other, which are fixedly connected to one of the drive shafts  16 , run off the spur gear. When the drive shafts  14  turn, the planetary gears  19  also turn synchronously via the spur gears  18  and the rollers or gripping members  20  turn synchronously via the drive shafts  16  and the bevel gears  42 . Arrows  50  in FIG. 2 show the rotational directions of the rollers or gripping members  20 .  
         [0023]    Each roller or gripping member  20  is respectively arranged in a V-shaped gap  51  that is open toward the outside, as shown in FIG. 4. In addition, each roller or gripping member  40  may be provided with a curved outer shell surface  40 , which forms a circular contour together with an outer shell surface  26  of support or carrier  15 . The outer shell surfaces of the rollers or gripping members,  20  as well as the carriers  15  are provided with a rubber-elastic lining  28  and  21 , as shown in particular in FIG. 3.  
         [0024]    Two additional shafts  39  are positioned above the carriers  15  on the two bearing plates  9  and  10  and are also driven with toothed belts  12 . These shafts respectively drive three endless top conveying belts  31 , which respectively operate jointly with a bottom conveying belt  30  for the continued transport of printed products  5 . FIG. 3 shows that the belts  31  and  30  form two conveying arrangements  52  and  53 , between which a deflection roller  33  is arranged that feeds the printed products  5  selectively to the conveying arrangement  52  or  53 . If the deflection roller  33  is in the position shown in FIG. 3, the printed products  5  are fed to the conveying arrangement  53 . By pivoting the deflection roller  33  counterclockwise around a horizontal axis  33   a,  a position can be adjusted in which the printed products  5  are fed to the conveying arrangement  52 . The deflection roller  33  is adjusted with control means that are not shown herein. The conveying arrangements  52  and  53  cause the printed products  5  to be deflected to an essentially horizontal plane. In the process, the printed products  5  are supplied, for example, to a cutting device  41  that is only indicated in FIG. 4, e.g. a three-side trimmer.  
         [0025]    The operating mode for the extension arm  1  according to the invention is explained in the following.  
         [0026]    [0026]FIG. 1 shows that the double gathering chain  2  conveys the printed products  5  in the direction of arrow  6  and thus into the region where they are picked up by the lift-off sword  34 . With this lift-off sword  34 , respectively one printed product  5  is picked up on the inside of fold  5   a  and is lifted up. FIGS. 1 and 3 show a printed product  5 ′ that is picked up by the lift-off sword  34  and is lifted up. During the continued transport, the lift-off sword  34  then dips down once more between the two chains  3  and  4  and picks up the following printed product  5  and lifts it up in the same way. As shown clearly in FIG. 3, the lifted up printed product  5 ′ is gripped in the region of fold  5   a ′ by the rollers or gripping members  20 , arranged in pairs. The lift-off sword  34  has comb-type design that corresponds to that of the rollers or gripping members  20 , as mentioned in the above, so that the lift-off sword  34  is not picked up by the rollers or gripping members  20 . As a result of the rotation of support or carrier  15 , the picked up printed product  5 ′ is accelerated in vertical upward direction. At the same time, a horizontal acceleration takes place in the conveying direction of the double gathering chain  2  and thus in the direction of arrow  6 , which is caused by the rotation of the rollers or gripping members  20 . This horizontal acceleration is at the highest value for the arrangement shown in FIG. 3 since the diameter D of these rollers  20  is largest in the pick-up region for these rollers or gripping members  20 . During the further conveying of printed products  5 ′, the diameter D of the rollers or gripping members  20  continues to get smaller and, accordingly, the horizontal speed of the printed product  5 ′ decreases. FIG. 4 shows the printed product  5 ′ in a phase, in which the smallest diameter D is effective. The fold  5   a ′ in that case is already in the region of conveying arrangement  53 . The printed product  5 ′ is deflected into the region of conveying arrangement  53  through a corresponding adjustment of the deflection roller  33 .  
         [0027]    [0027]FIG. 4 shows the phase in which the printed product  5 ′ is lifted up far enough to be nearly completely off the gathering chain  2 . The horizontal speed of printed product  5 ′ in that case is essentially zero and the product is conveyed by the conveying arrangement  53  and the supports  15 , which grip the lower edge of the printed product  5 ′. The printed product  5 ′ is then deflected to an essentially horizontal plane and is supplied to the cutting device  41  where it is trimmed on three sides.  
         [0028]    Following a rotation of 180° by the support  15 , the aforementioned conveying operation is repeated with the following printed product  5 . The printed product  5  is thus picked up in the aforementioned manner by the emerging lift-off sword  34  and is moved to the effective range of three rollers or gripping members  20  that operate in pairs. If the printed product  5  is thicker or thinner than the printed product  5 ′, then the lining  28  or  21  accordingly is compressed more or less. To accommodate even greater differences in the thickness, a design is conceivable for which the supports  15 , for example, can be compressed pneumatically to the respective product thickness. For this, the distance between the two drive shafts  14  is changed based on the product thickness. The product thickness can be detected with sensors, not shown herein, and the corresponding value can be used to control the adjustment of the drive shafts  14 .  
         [0029]    The conveying arrangement  52  can be used to feed incomplete products  5  to a waste paper box that is not shown herein. Of course, the deflection roller  33  must then be adjusted accordingly. Incomplete printed products of this type can also be detected with a sensor. The deflection roller  33  is adjusted accordingly, so that these printed products are supplied with the conveying arrangement  52  to the waste paper box.  
         [0030]    With the exemplary embodiment shown herein, the products  5  are picked up respectively by three roller pairs. In principle, a design is conceivable where the printed products  5  are picked up by only one roller pair or by more than three roller pairs. Also conceivable are designs where only one roller or gripping member  20 , or more than two rollers or gripping members  20 , are positioned on the supports or carriers  15 . As previously mentioned, the lift-off sword  34  can be movable or stationary. In principle, other means can also be used to move the printed products  5  into the region where they are picked up by the rollers or gripping members  20 .  
         [0031]    The invention has been described in detail with respect to preferred 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.