Abstract:
The transfer device is a circular conveyor having a plurality of radially moveable grippers. The grippers receive a non-self-supporting package, such as a newspaper jacket, on its bottom edge from an overhead line conveyor and rotate the newspaper down onto a receiving device such as a bundler at the bottom of the drum&#39;s rotation. The transfer device controls the gripping of the newspaper from the line conveyor with an inhibitor cam to provide a controlled bypass mechanism. The radial moveable grippers allow for smoother transistion and decrease space needs.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present Invention relates to a device for transferring flat, flexible, non-self-supporting printed products from a line conveyor to a receiving device like a conveyor or a bundler. The present Invention is especially useful for handling newspapers. 
     2. Art Relating to the Invention 
     In the graphic arts industry, flat, flexible, non-self-supporting printed products, such as newspapers and magazines, are moved by line conveyors. At some point along their path, the product has to be transferred from the line conveyor to another conveyor, a bundler, or other type of receiving device for further processing a stacker. The bundler/stacker prepares stacks of product for shipment, future binding, handling, or processing. 
     Typically, a line conveyor, as employed in the graphic arts industry, is a horizontally oriented endless chain which is equipped with a plurality of vertically oriented grippers. The grippers clamp the top edge of the product and transports the product to the receiving device. When the product arrives at the receiving device, the gripper opens its jaws to allow the product to fall from the gripper onto another conveyor, a platform or stack of other products, depending on the type of receiving device to which the product is transferred to at the transfer point. 
     One of the transfer devices used with bundlers/stackers as taught in U.S. Pat. No. 5,218,813 uses a circular conveyor which transfers the product from the line conveyor to the bundler/stacker. The circular conveyor employs grippers which grip the bottom edge of the product and rotate the product around to the bundler/stacker. 
     There is a point in time, just prior to release of the product from the line conveyor gripper, when the product is held by both the line conveyor gripper and the circular conveyor gripper. At this point in time, the product is subject to forces in opposite directions which can lead to problems in transferring the product from one conveyor to the other. 
     Additionally, there are times when the product is intended for a subsequent bundler/stacker and the line conveyor gripper does not release the product. In this situation, the circular conveyor grippers pulls the product out of the jaws of the line conveyor grippers. There is a need to avoid the fight between the line conveyor grippers and the circular conveyor grippers. 
     SUMMARY OF THE INVENTION 
     It has now been discovered that, by employing a circular conveyor with each circular conveyor gripper having both radial and circular motion, that a smooth transition of the product occurs between the line conveyor gripper and the circular conveyor gripper. The grippers of the circular conveyor gripper receive the product directly from the jaws of the line conveyor gripper and move the product to deposit it directly to a receiving device. Radial movement is suitably provided by mounting each circular conveyor gripper on a slide which moves the gripper in a radial direction with respect to the rotation of the circular conveyor. 
     The circular conveyor grippers of the present Invention are conventional grippers wherein the jaws are spring biased in a closed position and cams are used to open the jaws. Opening cams, positioned at the top and bottom of the rotational path of the circular conveyor, are employed for opening the circular conveyor grippers using a conventional cam follower which is mounted on one of the jaws of the circular conveyor gripper. The top opening cams are employed for opening the circular conveyor gripper to receive the product and the bottom opening cam for opening the circular conveyor gripper to deposit the product onto the receiving device. 
     It has also been discovered that an inhibiting cam device, which controls the closing of the circular conveyor gripperas it receives the product, provides better control for receiving the product and avoids a tug of war between the line conveyor gripper and the circular conveyor gripper when the product is intended to be carried by the line conveyor to a subsequent receiving device more particularly, the inhibiting cam device is a rotatable assembly of a plurality of inhibiting cams which act on the circular conveyor gripper as it closes about the product and starts its downward movement to the stacker/bundler. 
     Additionally, it has been found that, if the bottom opening cam is adjustable as to the release point of the product, the bottom opening cam allows for a constant point of release of the product regardless of the thickness of the product. 
     Preferably, a copy stripper is mounted opposite the bundler/stacker so as to remove the product from the jaws of the circular conveyor gripper. 
     It is also preferred that one or more pans be employed adjacent to the circular conveyor but, downstream of the circular conveyor, so that, as the product is received from the line conveyor gripper, it is controlled during its movement downward to the receiving device 
     Preferably, the receiving device employed with the transfer device of the present Invention is a bundler/stacker. 
     When the receiving device is a bundler/stacker, it is preferred that the stacking fork of the bundler/stacker have a homing sensor to permit automatic setting of the stacking fork relative to the circular conveyor. 
     These and other aspects of the present Invention will be more readily understood by reference to one or more of the following drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of the transfer device of the present Invention employed as a bundler infeed device; 
         FIG. 2  is a perspective view of the inhibiting cam assembly; 
         FIG. 3  is a front view of the inhibitor cam assembly and a circular conveyor gripper shown in inhibited position; 
         FIG. 4  is a side view of  FIG. 3 ; 
         FIG. 5  is a front view of the circular conveyor gripper and inhibited assembly showing the circular conveyor gripper uninhibited; 
         FIG. 6  is a side view of  FIG. 5 ; 
         FIG. 7  illustrates a side view of the device of  FIG. 1 ; and 
         FIG. 8  illustrates a cross section of the device taken along line A—A of FIG.  7 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the detailed description of the Invention, reference will be made to newspaper jackets or, more simply, jackets as the flat, flexible, non-self-supporting printed product. Additionally, reference will be made to a bundler/stacker as the receiving device. It will be understood that other receiving devices can be employed with the present Invention and that other products besides newspapers can be handled by the present Invention. 
       FIG. 1  illustrates a preferred embodiment of the transfer device of the present Invention employed as a bundler infeed device wherein a circular conveyor shown as gripper drum  20  has a plurality of circular conveyor grippers or drum grippers  22  positioned around its periphery. Drum grippers  22  have been numbered  1  through  12  to distinguish each from the other. Gripper drum  20  rotates about center of  24  in the direction of arrow A. Drum grippers  22  follow drum gripper tip path  26 . Drum grippers  22  are mounted on slide  28  which provides the radial movement of drum grippers  22 . 
     Drum grippers  22  are of a conventional construction having jaws which are spring biased in a closed position as shown by drum gripper No. 11, for example. 
     Gripper drum  20  is positioned below line conveyor  30 . Line conveyor  30  has a plurality of line conveyor grippers  34  which hold jacket  32  of a newspaper. Conveyor  30  moves in the direction of arrow B. 
     Below gripper drum  20  is positioned articulating stacking fork  36  and its articulating mechanism  38 . Drum grippers  22  receive jacket  32  and deposits jacket  32  onto fork  36 , all this being accomplished by the rotation of gripper drum  20  in the direction of arrow A. 
     In order to open drum grippers  22  as they move to the top of the rotation of gripper drum  20 , top opening cam  40  is fixed in position on the outside of gripper drum  20 . As shown in  FIG. 1 , top opening cam  40  acts on gripper Nos.  1 ,  2 ,  3 , and  4  as they rotate towards the top of their path of rotation. Top opening cam  40  operates on drum grippers  22  in a conventional manner by means of cam follower  66  which is part of each of drum grippers  22 . 
     In order to control the closing and removal of jacket  32  from line conveyor gripper  34 , inhibiting cam assembly  41  is used to control the closing of drum grippers  22  about jacket  32 . Inhibiting cam assembly  41  employs a plurality of inhibiting cams  42  which rotate about center  43 . As shown in  FIG. 1 , inhibiting cams  42  have been numbered to correspond with drum grippers  22  upon which they act. In other words, as shown in  FIG. 1 , inhibiting cam No.  6 ,  12  operates on drum gripper No.  12  and drum gripper No.  6 . Likewise, inhibiting cam No.  5 ,  11  operates on drum gripper No.  11  and drum gripper No.  5 . As will be appreciated, the number of inhibiting cams  42  is half the number of drum grippers  22 . As also will be appreciated, inhibiting cam assembly  41  rotates twice around for each rotation of gripper drum  20 . 
     As jacket  32  is carried to the bottom of the rotational cycle of gripper drum  20 , bottom opening cam  44  operates on cam follower  66  to open drum gripper  22  and allow jacket  32  to be deposited on articulating stacking fork  36  or the stack of jackets  32  which are on stacking fork  36 . Bottom opening cam  44  is adjustable to accommodate different thickness of newspaper and functions in a conventional manner by forcing one of the jaws away from the other. 
     In order to assist in the depositing jacket  32  under fork  36 , copy stripper  46  is employed. Copy stripper  46  is a conventional piece of equipment which is employed in a conventional manner in order to assist in a speedy removal of jacket  32  onto fork  36 . In  FIG. 1 , only one cam follower  51  is illustrated for drum gripper No.  9  in a breakaway portion of FIG.  1 . The non-circular movement of the drum grippers  22  is provided by cam surface  50   a  on cam follower  51 . The radial motion of drum gripper  22  is illustrated by drum gripper tip path  26 . As can be seen, this path is somewhat flat at the top of rotation of drum  20 , such that the line of travel of drum gripper  22  is approximately parallel to the line of travel of line conveyor gripper  34 . This aids in avoiding a tug-of-war and aids in a smooth transition of jacket  32  from line conveyor gripper  34  to drum gripper  22 . 
     The radial motion of drum gripper  22  is also evident in the downward path of drum gripper  22  wherein the downward path of drum gripper  22  is approximately vertically downward as shown in FIG.  1 . 
     Furthermore, the radial movement of drum gripper  22  is seen at the area of contact between drum gripper  22  and stacking fork  36 . By having the line of travel of drum gripper  22  approximately parallel to the flat surface of fork  36 , a smooth transition between the circular conveyor and the bundler is obtained. 
     Additionally, by employing radial movement for drum gripper  22 , a space savings is obtained. Obviously, an approximate parallel line of travel between line conveyor  30  and drum gripper  22 , and fork  36  and drum gripper  22 , can be obtained if the diameter of drum  20  is very large. Radial movement of drum gripper  22  allows for a smaller diameter drum while still obtaining relatively parallel movement. 
     Radial cam  50  is employed to act on a cam follower  51  mounted on each slide  28  to provide radial movement of drum gripper  22 . 
     In order to control the movement of jacket  32  during its downward decent from line conveyor  30  to fork  36 , upper pan  52  and lower pan  54  are employed. As will be appreciated, drum grippers  22  grabs the bottom edge of jacket  32  while pans  52  and  54  help maintain the top edge of jacket  32  in an upward direction during its downward movement. This assists in preventing inserts, which are in jacket  32 , from escaping. The distance, which pans  52  and  54  are spaced from tip path  26 , depends primarily on the size or dimension of jacket  32 . 
     As will be appreciated,  FIG. 1  does not illustrate the framework which is associated with the various elements. Such framework is conventional and is employed to maintain the relative position of the various elements. 
     Also, as will be understood, fork  36  and its associated articulated mechanism  38  is movable so as to move the stack of jackets  32  away from gripper drum  20  as the stack grows and to allow an empty fork  36  to be positioned in place. The stack, which is formed on fork  36 , can either be stored for future use or banded in a conventional manner for shipment. Both stacking fork  36  and its associated mechanism  38 , as well as a banding mechanism, are conventional. 
     Turning to  FIG. 2 , details of the inhibitor cam assembly  41  are illustrated in a perspective view. As shown in  FIG. 2 , there are six inhibitor cams  42  which are part of assembly  41 . Enabling cam  60 , which is shown in the retracted position in  FIG. 2 , is retracted by fluid activation from valve  62  as shown in FIG.  5 . In the retracted position, enabler cam  60  is retracted. Enabling cam  60  is spring loaded to be in an extended state as shown in  FIG. 3  without activation from air via fluid valve  62 . When enabling cam  60  is retracted, inhibiting cams  42  are in position to allow closing of drum gripper  22  by acting on cam follower  66 . Thus, opening and closing of drum grippers  22  is controlled via valve  62 . 
     Turning to  FIG. 3 ,  FIG. 3  illustrates enabling cam  60  in an extended position which, in turn, shows inhibitor cam  42  extended into the path of gripper cam follower  66 . With gripper cam follower  66  acted upon by inhibitor cam  42 , drum gripper  22  is maintained in a slightly open position as shown by drum gripper No.  12  in FIG.  1 . 
     Reset cam  64  operates on all inhibitor cam  42  to move them to the extended or inhibiting position as shown in FIG.  3 . This is the natural or rest position of inhibitor cam  42 . When inhibitor cam  42  is retracted, it moves to right in  FIG. 3 , gripper cam follower  66  is no longer acted upon by inhibitor cam  42  and drum gripper  22  can close on jacket  32 , as shown in FIG.  5 . 
       FIG. 4  illustrates drum gripper  22  and inhibitor cam assembly  41 , as shown in  FIG. 3 , wherein inhibitor cam  42  is operating on cam follower  66  to maintain drum gripper  22  in a slightly open position. 
     As shown in  FIG. 4 , drum gripper  22  follows the rotation as indicated by arrow A while inhibitor cam  42  rotates about center  43  and moves in the direction of arrow C. As will be appreciated, inhibitor cam assembly  41  is operated by belt  68  which is operated upon the axle that drives gripper drum  20 . As will be appreciated by one of skill in the art, inhibitor cam assembly  41  can be independently driven, however, it is suitable that a standard servo drive be employed so as to coordinate, not only the movement of gripper drum  20  with respect to conveyor  30 , but also to coordinate the movement of inhibitor assembly  41  and gripper drum  20 . 
     Turning to  FIG. 5 , enable cam  60  is shown in the retracted state which, in turn, allows inhibitor cam  42  to be in the retracted state and out of the path of cam follower  66 . In such an arrangement, drum gripper  22  closes so as to hold jacket  32  tightly between its jaws. Referring back to  FIG. 1 , this is the position of gripper No.  10  which is shown leaving the area of operation of inhibiting cam assembly  41  on its downward movement towards fork  36 . 
     By controlling the opening and closing of drum grippers  22  with inhibitor cam assembly  41 , selected jackets  32  can bypass one device of the present Invention and pass to a subsequent transfer device. 
     While only a limited number of specific embodiments of the present Invention have been expressly disclosed, it is, nonetheless, to be broadly construed and not to be limited except by the claims appended hereto.