Patent Publication Number: US-6910690-B1

Title: Positive control lower folder

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention lies in the signature transport and printing fields. Specifically, the invention relates to a positive control transport assembly such as used in a lower folder of a printing press assembly which positively controls a signature stream that is being diverted into two or more signature conveying streams. 
     A stream of printed products may be transported by a commonly known gripper conveyor. It is often desirable to split the common method of splitting a stream of products is to drag the initial stream over a vacuum belt traveling slower than the conveying system and to release every other signature from the gripper conveyor as soon as the respective signature contacts the vacuum belt. However, once the sheets are released their placement onto the vacuum belt fall according to a distributed pattern and the exact placement of the signature on the belt is not known. Consequently, correct alignment and a fixed pitch (a distance between the leading edge of two consecutive signatures in a product stream) of the signatures delivered to the vacuum belt cannot be guaranteed. 
     2. Description of the Related Art 
     U.S. Pat. No. 5,740,900 to Cote et al., for instance, describes an apparatus for splitting a product stream that includes a single conveying belt having a plurality of grippers traveling along a single conveyor path into two product streams. At least one of the grippers is capable of rotating a held signature from one side of the belt to the other side, so as to create a second parallel product stream. In this manner a single conveying belt forms two side by side product streams and at all times maintains positive control over the signatures. In this device the signatures are never released such as onto a vacuum belt that leads to the above mentioned distortions or pitch problems. 
     U.S. Pat. No. 5,560,599 to Curley et al. describes a deceleration device for slowing down signatures being transported in a folding machine. The deceleration device has a deceleration drum provided with a plurality of rotary grippers that positively grip an edge of the signatures exiting a tape conveyor system in the folding machine traveling at a high velocity. The grippers and drum decelerate the signatures before releasing them over a delivery stack. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a positive control lower folder, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type, in which the signature is positively controlled while being transferred to one of a plurality of transport paths. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a positive control signature transferring assembly, containing:
     a first positive control deceleration device having grippers for transporting some signatures of a stream of signatures to a first delivery stream;   a gripper cylinder containing a plurality of grippers for gripping a trailing edge and a leading edge of remaining signatures in the signature stream for transporting the remaining signatures on the gripper cylinder; and   a second positive control deceleration device having grippers for transporting the remaining signatures released by the gripper cylinder to a second delivery stream.   

     In accordance with an added feature of the invention, there further contains: a first high-speed tape deflected around the gripper cylinder; a deflection roller; and a second high-speed tape deflected around the deflection roller, the signatures being transported to one of the first positive control deceleration device and the gripper cylinder between the first high-speed tape and the second high-speed tape. 
     In accordance with an additional feature of the invention, the first positive control deceleration device and the second positive control deceleration device each have rotatable arms holding the grippers for gripping and decelerating the signatures. 
     In accordance with another feature of the invention, there are further deflection rollers, and a third high-speed tape deflected around the further deflection rollers, the remaining signatures being transported between the first high-speed tape and the third high-speed tape from the gripper cylinder to the second positive control deceleration device. 
     In accordance with a further added feature of the invention, the first positive control deceleration device and the second positive control deceleration device are deceleration drums. 
     With the foregoing and other objects in view there is further provided, in accordance with the invention, a method for positively controlling and diverting signatures, which includes:
     removing a batch of signatures from a signature stream with a first positive control deceleration device that grips and transports the batch of signatures to a first delivery stream, the signatures being positively controlled in their delivery to the first delivery stream;   transporting remaining signatures of the signature stream on a gripper cylinder having grippers gripping both a leading edge and a trailing edge of each of the signatures; and   removing the remaining signatures from the signature stream released by the gripper cylinder with a second positive control deceleration device gripping and transporting the remaining signatures to a second delivery stream, the signatures being positively controlled in their delivery to the second delivery stream.   

     In accordance with an added feature of the invention, there is the step of delivering the signatures to the first positive control deceleration device between a first high-speed tape and a second high-speed tape. 
     In accordance with a concomitant feature of the invention, there is the step of delivering the signatures to the second positive control deceleration device between the first high-speed tape and a third high-speed tape. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a positive control lower folder, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of the specific embodiment when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The single FIGURE of the drawing is a diagrammatic, side-elevational view of a positive control lower folder according to the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the single figure of the drawing in detail, there is shown a first high-speed tape  1  and a second high speed tape  2  enclosing a stream of signatures  3  therebetween. The first high-speed tape  1  is deflected around or in the vicinity of a gripper cylinder  4  having a plurality of grippers  5  disposed thereon. The second high-speed tape  2  is deflected around a deflection roller  6 . 
     A first positive control deceleration device  7  such as a deceleration drum containing a plurality of arms  17  having rotatable grippers  8  is provided for gripping the sheets  3  as they are released from in-between the high-speed tapes  1 ,  2 . The grippers  8  grab an edge of the sheets  3  and decelerate the sheets  3 . The sheets  3  are diverted to a first delivery stream  9  in which the sheets are positively controlled while being delivered to the first delivery stream  9 . In this manner, the placement of the sheet  3  in the first delivery stream  9  is guaranteed. 
     Should the sheets  3  be intended to be delivered to a second delivery stream  10 , the sheets  3  are engaged at both a leading edge  11  and a trailing edge  12  by two of the grippers  5  disposed on the gripper cylinder  4  and carried through a divert area. 
     A third high-speed tape  13  deflected around its deflection rollers  14  receives the sheets  3  delivered by the gripper cylinder  4 . The sheets  3  are transported between the first and third high-speed tapes  1 ,  13 . 
     A second positive control deceleration device  15  such as a deceleration drum containing a plurality of arms  18  having rotatable grippers  16  is provided for gripping the sheets  3  as they are released from in-between the high-speed tapes  1 ,  13 . The grippers  16  grab an edge of the sheets  3  and decelerate the sheets  3 . The sheets  3  are diverted to the second delivery stream  10  in which the sheets  3  are positively controlled while being delivered to the second delivery stream  10 . In this manner, the placement of the sheet  3  in the second delivery stream  10  is guaranteed. 
     The invention is shown with two positive control deceleration devices  7 ,  15  but could contain any number of positive control deceleration devices depending on the number of diversion paths desired.