Abstract:
An improved saddle stitcher incorporating alignment paddle which includes paddle  100 , a base  200 , and torque producing means wherein the torque producing means rotates the paddle which contacts and jogs passing signature groups, thereby aligning them.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention generally relates to an improved saddle stitcher, specifically the incorporation of a signature alignment paddle into the stitcher design. 
     2. Prior Art 
     In the past ten years, printing design has become much more complicated, with intricate page designs which sometimes include continuous images which cross over from one page to the next. Designs of this type require that the individual sheets (signatures) jog up or head up, meaning that the top of all sheets are precisely aligned. 
     For the past 30 years, a number of methods have been employed during the printing process for signature alignment. The standard method currently used to align the signatures is with the use of a piece of spring steel attached to the stitcher. The spring steel is oriented so that it hangs down just above the signatures. It is typically bent by hand so that it lightly drags across the signatures. The intent is that this dragging action will pull the signatures against a stop and thereby align them. This method has a number of shortcomings however. Sometimes a signature rides too high on the saddle and the spring steel drags the signature off the conveyor chain, or creates a jam-up on the chain. Sometimes the spring steel pressure is too high and the steel scratches the signature. Other times the pressure is too low and the device fails to move the signature against the stop. 
     Another method currently used for signature alignment is the use of one or more strings mounted to the saddle stitcher. The strings are positioned in such a way as to drag along the outside of the signature as it passes. This dragging is intended to draw the signature back to a stop, where presumably it would align with a signature underneath. This method also has a number of drawbacks. First, excess drag by the string will dislodge the signature and will disrupt production. This is especially common when the signatures are textured or otherwise coated with a substance which tends to stick to the string. In addition, this method is only effective at dragging the top signature. It is not uncommon in production runs however, to have as many as six or more signatures gathered. In these cases, the string would typically only pull the top layer to the stop. 
     A third method is to simply place an individual along side the production line and have them manually jog each signature group to achieve the desired alignment. This method has a number of shortcomings however. First, it requires the employment of one or more individuals and adds to the cost of production. Second, manual jogging requires that the production rate be slowed to accommodate the reflexes of the average person. 
     OBJECTS AND ADVANTAGES 
     The object of the present invention is to provide an improved saddle stitcher which will precisely align multiple signatures simultaneously, which is not sensitive to surface texture of the signatures, will accommodate any production rate, and does not require manual action. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention incorporates a stitcher paddle into the saddle stitcher. The stitcher paddle is mounted on a pivot and is rotated into the signature group as it passes, jogging and aligning the individual signatures. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is an elevation view of the preferred embodiment of the stitcher paddle. 
         FIG. 2  is a plan view of the preferred embodiment of the stitcher paddle. 
         FIG. 3  is a plan view of the first step in a sequence illustrating the operation of the preferred embodiment. 
         FIG. 4  is a plan view of the second step in a sequence illustrating the operation of the preferred embodiment. 
         FIG. 5  is a plan view of the third step in a sequence illustrating the operation of the preferred embodiment. 
         FIG. 6  is a plan view of the fourth step in a sequence illustrating the operation of the preferred embodiment. 
         FIG. 7  is a plan view of the fifth step in a sequence illustrating the operation of the preferred embodiment. 
         FIG. 8  is a plan view of a first alternate embodiment of the present invention. 
         FIG. 9  is a plan view of a second alternate embodiment of the present invention. 
         FIG. 10  is a plan view illustrating operation of the first alternate embodiment of the present invention. 
         FIG. 11  is a plan view illustrating operation of the second alternate embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The preferred embodiment of the present invention is illustrated in  FIGS. 1 and 2 . As indicated therein, it consists of a paddle  100 , a base  200 , a clamp  300 , a tightening screw  400 , a spring  500  and a saddle stitcher  1000 . The saddle stitcher  1000  is considered prior art and no further discussion is provided herein. 
     The paddle  100  has a front side  104  and a back side  105 . It has a cantilevered end  106  and a supported end  107 . It is outfitted on the cantilevered end  106  with a polytetrafluoroethylene (PTFE) pad  101  on the front and back sides, a rubber pad  102  on the back side  105 , and a pivot post  103  at the supported end  107 . The pivot post  103  is outfitted with a concentric hole  108 . 
     The base  200  has a front end  204  and a back end  205 . It has a top  206  and a bottom  207 . It has a stop  201  which is attached substantially at the front end  204  on the top  206  of the base  200 . It has a pivot pin  202  attached to the top  206  in a position closer to the back end  205  than the stop  201 . The pivot pin is substantially round with a diameter substantially equal to the diameter of the pivot post concentric hole  108 . The base  200  also has a spring mounting post  203  located on the top  206  near the back  205  of the base  200 . The base also has a threaded hole  208  located between the spring mounting post  203  and the back  205 . 
     The clamp  300  consists of an upper jaw  301  and a lower jaw  302 . The upper jaw has a substantially concentric hole  303  and the lower jaw has a substantially concentric hole  304 . The concentric holes are slightly larger than the threaded hole  208  in the base  200 . 
     The tightening screw  400  consists of a threaded stud  401  and a handle  402 . The threaded stud  401  is sized to engage with the threads on the threaded hole  208  in the base  200 . 
     The spring  500  consists of a front end  501  and a back end  502 . The front end  501  is attached to the pivot post  103  of the paddle  100 , and the back end  502  is attached to the spring mounting post  203 . 
     A sequence illustrating the operation of the preferred embodiment of the present invention is illustrated in  FIGS. 3 through 7 . As indicated in  FIG. 3 , a signature group  600  is carried by a conveyor chain  700  toward the paddle  100 . The chain  700  is outfitted with a stop  701 . As illustrated in  FIG. 3 , there typically exists a small gap  800  between the stop  701  and signature group  600 . The paddle  100  is oriented substantially perpendicular to and slightly above the conveyor chain  700 . 
     Referring to  FIGS. 4 and 5 , as the conveyor chain  700  carries the signature group past the paddle  100 , the paddle  100  is rotated counterclockwise as required to allow the group to pass. This counterclockwise motion stretches and preloads the spring  500 . Referring to  FIG. 6 , after passage of the first signature group, the pre-loaded spring rotates the paddle  100  clockwise to return it to its original position. Note also in  FIG. 6 , the misalignment  601  of the incoming signature group. Referring to  FIG. 7 , as this clockwise motion continues, it eventually comes in contact with and jogs the following signature group  600 , pushing all signatures against the stop  701  and into alignment  602 . As the second signature group continues to be conveyed past the paddle, it rotates the paddle in a counterclockwise movement, and the process is repeated for subsequent signature groups. 
     A number of alternate embodiments of the present invention are possible. A first alternate embodiment is illustrated in  FIG. 8 . As indicated therein, an eccentric spring mounting post  1203  is incorporated into the design. 
     A second alternate embodiment is illustrated in  FIG. 9 . As indicated, the spring is replaced by an assembly consisting of a sensor  2001 , three position solenoid valve  2002 , double-acting air actuated piston  2003 , power supply  2004 , and compressed air supply  2005 . The piston  2003  is connected to the paddle assembly by piston pin  2006  which is engaged to a torque arm  2007  connected to the pivot post  103 . 
     The operation of the first alternate embodiment is illustrated in  FIG. 10 . As indicated therein, an eccentric spring mounting post  1203  is rotated as desired to develop an optimum spring tension. 
     The operation of the second alternate embodiment is illustrated in  FIG. 11 . As indicated therein, a sensor  2001  connected to power supply  2004  detects the position of the signature group  600 . As the signature group reaches the optimum position, a signal is sent to a three way solenoid valve  2002  which directs compressed air  2005  to a double acting piston  2003  which exerts force on torque arm  2007  through pin  2006 . 
     The alternate embodiments described above may be implemented singly or in any combination to suit the specific needs of the end user, and although the descriptions above contain many specifics, these should not be construed as limiting the scope of the invention, but merely providing illustrations of some of the presently preferred embodiments. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.