Abstract:
A signature transport device is provided. The signature transport device includes a first conveyor moving a stream of folded signatures in a first direction, a rotary arm having a gripper, the gripper gripping a folded signature from the stream by a fold, the rotary arm moving the folded signature in a second direction, a toothed drum engaging a portion of the folded signature, the rotary arm rotating past the toothed drum to open the folded signature and a second conveyor receiving the opened signature from the gripper as the rotary arm continues to rotate. A method is also provided.

Description:
BACKGROUND 
     The present invention relates generally to post press printing equipment and more particularly to signature feeders and saddle conveyors. 
     U.S. Pat. No. 6,375,179 purportedly discloses a device for opening and depositing a folded signature onto a moving conveyor, particularly a collecting chain. The device includes two opening rollers with axes that extend essentially parallel to the conveying direction of the conveyor and respectively open one signature and deposit it with the opened side first in a downwardly direction onto the conveyor, wherein the signatures are pre-accelerated in the conveying direction of the conveyor. 
     U.S. Pat. No. 7,192,027 discloses a signature transport device which includes a first conveyor moving a plurality of folded signatures in a first direction and a second conveyor including a first blade having a first edge for lifting a first signature of the plurality of signatures from the first conveyor. 
     U.S. Pat. Nos. 7,530,564 and 7,631,914 and U.S. Publication No. 2008/0007075 A1 disclose a gripping device for gripping printed products. The gripping device includes a gripper having a first gripper arm having a first gripper pad on one end rotatable about a first pivot and a second gripper arm having a second gripper pad on one end rotatable about a second pivot. 
     U.S. Publication No. 2009/0309289 purportedly discloses an apparatus for withdrawing flat products from a stack and transporting the printed products. The apparatus includes a transporting device, a separating device and a rotating conveyor. The rotating conveyor includes at least one gripper with a gripper plane to grip a separated printed product in the gripper plane and supply the separated printed product to the transporting device. 
       FIG. 1  shows a conventional hopper apparatus  10 . Hopper  10  includes a stack  12  of sheets or signatures which may be folded printed products. Each printed product is transported from a bottom of stack  12  to a gripper drum  20 . As shown in  FIG. 1 , signature  14  is held onto gripper drum  20  via a gripper  22 . Gripper drum  20  may include a plurality of grippers  22 . As shown in  FIG. 1 , gripper drum  20  includes three grippers. A suction element  16  may aid the removal of the bottommost signature from stack  12 . A spine of the folded signature is pulled down by suction element  16  then gripped by gripper  22  so the spine of signature  14  is tucked into gripper drum  20 . Gripper drum  20  rotates in a counterclockwise direction until signatures  14  reaches a register stop  24 . Register stop  24  provides a consistent location for lining up a lap in the tail open end of signature  14  for transfer to opening drums  30 ,  32 . Signature  14  is then transported in a different direction via guide  26 , with the tail open end of the folded signature now leading. Signature  14  is transported to opening rollers  30 ,  32 , which open signature  14  by each gripping a leg of signature  14 . Opening rollers  30 ,  32  open signatures  14  as the rollers  30 ,  32  rotate and drop signature  14  onto a saddle conveyor or collecting chain  40 . 
     BRIEF SUMMARY 
     The operating speed of a conventional hopper and opening drum device may be limited due to the directional and speed changes undergone by the transferred signatures. The signature is pulled from the stack, spine-leading, accelerated around the transfer drum then stopped by the register stop. The signature is then accelerated again in a different direction with the previous tail end, now leading. These directional and speed changes of the signature may reduce speed and output of the hopper. 
     In addition, the conventional hopper and opening drum device feeds signatures at a right angle to the saddle conveyor or collecting chain. The signatures are dropped from the opening drums at a height above the saddle conveyor or chain. A lug or register block on the conveyor or chain then contacts the signature and accelerates the signature with the conveyor or chain. This may occur as soon as the signature lands on the chain or conveyor. The impact of the lug/register block on the signature may be severe, especially at high conveyor or chain speeds and may cause damage to the signatures. 
     The present invention provides a signature transport device including a first conveyor moving folded signatures in a first direction, a rotary arm having a gripper, the gripper gripping a folded signature from the stream by a fold, the rotary arm moving the folded signature in a second direction, a toothed drum engaging a portion of the folded signature, the rotary arm rotating past the toothed drum to open the folded signature and a second conveyor receiving the opened signature from the gripper as the rotary arm continues to rotate. 
     The present invention further provides a signature transport device including a hopper having a horizontal stack of folded signatures, a first conveyor receiving the folded signatures from the hopper to form a stream of folded signatures moving in a first direction, a rotary arm having a gripper, the gripper gripping a folded signature from the stream by a fold, the folded signature being in a plane of the gripper, the rotary arm rotating about an axis perpendicular to the axis of the gripper plane and moving the folded signature in a second direction while the signature remains in the gripper plane and a second conveyor receiving the signature from the gripper as the rotary arm continues to rotate, a plane of the conveyor receiving the signature overlapping with the gripper plane when the signature is deposited on the conveyor. 
     The present invention also provides a saddle stitcher. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a conventional hopper apparatus for moving signatures from a hopper to a saddle conveyor; and 
       A preferred embodiment of the present invention will be elucidated with reference to the drawings, in which: 
         FIG. 2  shows a post press saddle stitcher including a gripper arm transfer device in accordance with an embodiment of the present invention; 
         FIGS. 3 to 6  show the gripper arm transfer device depositing signatures onto a chain conveyor according to the present invention; and 
         FIGS. 7A to 7D  schematically show the gripper arm transfer device moving a signature in a plurality of positions. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 2  shows a preferred embodiment of a saddle stitcher  200  including a plurality of gripper arm transfer devices  100  in accordance with the present invention. Saddle stitcher  200  also includes a stitching device  210  which may include a plurality of stitching heads  212  for stitching a book or printed product  220  formed on a conveyor  118 . A book may be formed by collecting multiple printed products from transfer devices  100  at a same location on conveyor  118 . Conveyor  118  may be for example, a saddle conveyor or inserter chain. A lug or register pin  222  may be used to register each of the printed products and/or resulting book. Hoppers  216  may collect or stack signatures  120  which are transported to gripper arm transfer devices  100  via a first conveyor device, for example, one including tapes  102 ,  104  ( FIG. 4 ). Signatures  120  may be orientated horizontally in hopper  216  as shown in  FIG. 2 . A sucker bar  218  or grippers may retrieve signatures  120  from hoppers  216  in a known manner. A drum or other device may be used as well between sucker bar  218  and tapes  102 ,  104 . Signatures  120  are then further transported to conveyor  118 . Alternatively, gripper arm transfer device  100  may be directly coupled to a folder of a printing press. 
       FIGS. 3 to 7D  show the gripper arm transfer device  100  in more detail. Gripper arm transfer device  100  includes a pair of upper tapes  102  and a pair of lower tapes  104 , a padded drum  106 , a rotary arm  110 , toothed drum  112  and an inserter or saddle chain  118 . Rotary arm  110  includes four arms  111  each of which include a gripper  108 . 
     A folded signature  120  is fed to tapes  102 ,  104  via a sucker bar  218  ( FIG. 2 ). Signatures  120  may be fed from a stack of signatures, for example, a stack collected by hopper  216  ( FIG. 2 ). Each folded signature  120  includes a fold  121  and may be folded unevenly, so a lap  130  exists. Thus, folded signature  120  has a long leg  132 , the longer side of the signature, and a short leg,  134 , the shorter side of the signature. Signature  120  enters the tapes  102 ,  104  spine leading and travels in tapes  102 ,  104  to gripper  108  on rotary arm  110 . Padded drum  106  assists in transfer of signature  120  from tapes  102 ,  104  to gripper  108 . Each gripper  108  includes a plurality of brackets, guides and a finger  128 . Gripper  108  receives signature  120  when an arm  111  is in a nine o&#39;clock position as shown in  FIG. 7A . At the area of receipt, signature  120  in tapes  102 ,  104  is moving at a speed slightly faster than a vertical velocity of gripper  108  on arm  111  so signature  120  registers in gripper  108 . 
     Gripper  108  can rotate with respect to rotary arm  110  and maintains signature  120  in an upright orientation parallel to chain  118  throughout the rotation of rotary arm  110  until signature  120  is deposited on chain  118  as shown in  FIGS. 7A to 7D . Rotary arm  110  rotates in a clockwise direction D and moves arm  111  from the nine o&#39;clock position shown in  FIG. 7A  to a twelve o&#39;clock position shown in  FIG. 7B . Signature  120  remains upright during the rotation. Rotary arm  110  rotates about a rotary axis  109 . Preferably, rotary arm  110  rotates continuously. Thus, signature  120  is constantly being transported and does not need to be stopped during the transfer process. From the twelve o&#39;clock position, rotary arm continues to rotate to a three o&#39;clock position while gripper  108  continues to adjust in order to maintain signature  120  in an upright orientation as shown in  FIG. 7C . Around the three o&#39;clock position, the lap  130  of signature  120  strikes toothed drum  112  which forces signature  120  open. Teeth  122  on toothed drum  112  are cammed open so there is sufficient clearance for lap  130  to enter teeth  122 . After lap  130  enters teeth  122 , teeth  122  are cammed close on a long leg  132  of signature  120 , however, teeth  122  do not grip signature lap  130  or short leg  134 . 
     As rotary arm  110  continues to rotate, a body of signature  120  is traveling at a speed faster than long leg  132  in toothed drum  112  so long leg  132  stays in teeth  122  while short leg  134  is forced open. Once short leg  134  is forced open, finger  128  on gripper  108  is actuated up to go under short leg  134 . Finger  128  ensures signature  120  stays open as signature  120  straddles chain  118 . 
     Finally, rotary arm  110  rotates arm  111  and gripper  108  to a six o&#39;clock position. At or near the six o&#39;clock position, gripper  108  releases signature  120  onto conveyor  118 . Once signature  120  straddles chain  118 , finger  128  releases short leg  134 . At this point, a horizontal velocity of signature  120  is near a velocity of chain  118 . A plane of gripper  108  gripping signature  120  coincides with a plane of conveyor  118  which eases the transition of signature  120  from gripper  108  to conveyor  118  resulting in less damage to signature  120 . Thus, in accordance with the present invention, signature  120  is not stopped during the transfer process and the velocity of signature  120  when signature  120  is placed on chain  118  is close to the velocity of the chain  118 . Rotary arm  111  then returns to the nine o&#39;clock position to grip a subsequent signature from tapes  102 ,  104 . 
     In accordance with another preferred embodiment, gripper arm signature feeder  100  may be coupled directly to a folder and not use a sucker bar or rotor drum to singulate signatures. The folder would feed a stream of singulated signatures into a path of rotary arm as described above. The rotary arm  110  would then grip, open and transfer the signatures to a chain in the same manner as described above. 
     In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.