Abstract:
A method for automated insertion of a collation into an envelope. The envelope is fed onto an insert station. A preferred insertion depth is determined for the collation to be inserted into the envelope. The collation is pushed via a pusher that moves at a constant velocity towards an open end of the envelope. The location of the pusher is monitored as it approaches the insert station. The envelope is accelerated in the downstream direction from its stopped position to the constant velocity of the pusher. Acceleration is triggered by the pusher reaching a position whereby the envelope and the pusher will match velocities at the same time that the collation is at the insertion depth. As a result, the collation is inserted in the envelope to the insertion depth at the same time that the velocity of the envelope matches the velocity of the pusher.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to multi-station document inserting systems, which assemble batches of documents for insertion into envelopes. More particularly, the present invention is directed motion control for optimized insertion of a collation into an envelope. 
       BACKGROUND OF THE INVENTION 
       [0002]    Multi-station document inserting systems generally include a plurality of various stations that are configured for specific applications. Typically, such inserting systems, also known as console inserting machines, are manufactured to perform operations customized for a particular customer. Such machines are known in the art and are generally used by organizations, which produce a large volume of mailings where the content of each mail piece may vary. 
         [0003]    For instance, inserter systems are used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mailings where the contents of each mail item are directed to a particular addressee. Additionally, other organizations, such as direct mailers, use inserts for producing a large volume of generic mailings where the contents of each mail item are substantially identical for each addressee. Examples of such inserter systems are the MPS and Epic™ inserter systems available from Pitney Bowes. Inc., Stamford, Conn. 
         [0004]    In many respects the typical inserter system resembles a manufacturing assembly line. Sheets and other raw materials (other sheets, enclosures, and envelopes) enter the inserter system as inputs. Then, a plurality of different modules or workstations in the inserter system work cooperatively to process the sheets until a finished mailpiece is produced. The exact configuration of each inserter system depends upon the needs of each particular customer or installation. For example, a typical inserter system includes a plurality of serially arranged stations including an envelope feeder, a plurality of insert feeder stations and a burster-folder station. There is a computer generated form or web feeder that feeds continuous form control documents having control coded marks printed thereon to the burster-folder station for separating and folding. A control scanner located in the burster-folder station senses the control marks on the control documents. Thereafter, the serially arranged insert feeder stations sequentially feed the necessary documents onto a transport deck at each station as the control document arrives at the respective station to form a precisely collated stack of documents which is transported to the envelope feeder-insert station where the stack is inserted into the envelope. The transport deck preferably includes a ramp feed so that the control documents always remain on top of the stack of advancing documents. A typical modern inserter system also includes a control system to synchronize the operation of the overall inserter system to ensure that the collations are properly assembled. 
         [0005]    In regards to the envelope feeder-insert station they are critical to the operation of document inserting systems. Typically, such an envelope insert device inserts collated enclosures into a waiting envelope. Envelope inserting machines are used in a wide range of enclosure thickness and also with enclosures which are not significantly different in length than the length of the envelopes into which they are inserted. The difference between the length of the enclosures and the envelope should be minimized so that the addressing information printed on the enclosure which is intended to appear in the envelope window does not shift in position and become hidden. 
         [0006]    To ensure a quality finished mail piece in high speed inserting machines, it is necessary to accurately control the depth to which the collation is inserted into the targeted envelope. Typically this is achieved by staging and holding motionless an envelope and controlling only the motion of the inserting collation. This method leads to an undesired rapid acceleration of the stationary envelope once insertion is complete and increases equipment costs since it requires adjustable envelope holding mechanisms to function over many envelope sizes. 
         [0007]    Prior art inserting systems are described in the following patents, which are hereby incorporated by reference:
   U.S. Pat. No. 5,992,132—Rotary Envelope Insertion Horn   U.S. Pat. No. 6,978,583—High Speed Vacuum System for Inserters;   U.S. Pat. No. 7,181,695—Jam Tolerant Mail Inserter;   U.S. Pat. No. 7,600,755—System and Method for Preventing Envelope Distortion in a Mail Piece Fabrication System;   U.S. Pat. No. 8,281,919—System for Controlling Friction Forces Developed on an Envelope in a Mailpiece Insertion Module;   U.S. Pat. No. 8,439,182—Mail Piece Inserter including System for Controlling Friction Forces Developed on an Envelope.   
 
       SUMMARY OF THE INVENTION 
       [0014]    This invention holds the motion of the collation constant, and times the acceleration of the envelope to the velocity of the collation such that when the velocities match, the desired insertion depth has been achieved. This eliminates the violent acceleration of the envelope and reduces the cost and complexity of the mechanism without losing any functionality 
         [0015]    The invention provides for automated insertion of a collation into an envelope. The envelope is fed, with its flap open, onto an insert station. The envelope is stopped so that its flap crease line is at a predetermined location. A preferred insertion depth is determined for the collation to be inserted into the envelope. The insertion depth is a distance past the flap crease line for an upstream edge of the collation to be positioned once the collation is inserted into the envelope. The collation is pushed via a pusher that moves at a constant velocity towards an open end of the envelope. The location of the pusher is monitored as it approaches the insert station. The envelope is accelerated in the downstream direction from its stopped position to the constant velocity of the pusher. Acceleration is triggered by the pusher reaching a position whereby the envelope and the pusher will match velocities at the same time that the collation is at the insertion depth. As a result, the collation is inserted in the envelope to the insertion depth at the same time that the velocity of the envelope matches the velocity of the pusher. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The above and other objects and advantages of the present invention will become more readily apparent upon consideration of the following detailed description, taken in conjunction with accompanying drawings, in which like reference characters refer to like parts throughout the drawings and in which: 
           [0017]      FIG. 1  is a block diagram schematic of a document inserting system in which the present invention input system is incorporated; 
           [0018]      FIG. 2  is a side, elevational view of an envelope inserting apparatus; 
           [0019]    FIG. is a view similar to  FIG. 2 , but simplified to show the improved features and motion control elements. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    Referring to  FIG. 1 , a schematic of a document inserting system according to one embodiment of the present application is shown. The document inserting system  10  includes an insertion station  100 . The document insertion system  10  is illustrative and many other configurations may be utilized. 
         [0021]    System  10  includes an input system  12  that feeds paper sheets from a paper we to an accumulating station that accumulates the sheets of paper in collation packets. Preferably, only a single sheet of a collation is coded (the control document), which coded information enables the control system  14  of inserter system  10  to control the processing of documents in the various stations of the mass mailing inserter system. 
         [0022]    Input system  12  feeds sheets in a paper path, as indicated by arrow “a,” along what is known as the main deck of inserter system  10 . After sheets are accumulated into collations by input system  12 , the collations are folded in folding station  16  and the folded collations are than conveyed to a transport station  18 , preferably operative to perform buffering operations for maintaining a proper timing scheme for the processing of documents in insertion system  10 . 
         [0023]    Each sheet collation is fed from transport station  18  to insert feeder station  20 . It is to be appreciated that an inserter system  10  may include a plurality of feeder stations, but for clarity, only a single insert feeder  20  is shown. Insert feeder station  20  is operational to convey an insert (e.g., an advertisement) from a supply tray to the main deck of inserter system  10  so as to be combined with the sheet collation conveying along the main deck. The sheet collation, along with the nested insert(s), are next conveyed into envelope insertion station  100  that is operative to first open the envelope and then insert the collation into the opening of the envelope. The envelope is than conveyed to postage station  22 . Finally, the envelope is conveyed to sorting station  24  that sorts the envelopes in accordance with postal discount requirements. 
         [0024]    Referring now to  FIG. 2 , an insertion device  100  according to an illustrative embodiment of the present application is shown. In operation, an envelope enters the insertion station  100  along a guide path  114  and is transported into the insertion station  100  by a set of transport rollers  116  and  118  and continuously running transport belts  121 ,  123  and  125 . Each transport belt  121 ,  123  and  125  respectively wraps around rollers  127 ,  129  and  131 , each roller being connected to a common shaft  133   a . Each transport belt  121 ,  123  and  125  is juxtaposed between deck strips that form transport deck  141  of insertion station  100 . 
         [0025]    The motion of each transport belt  121 ,  123  and  125  is continuous for maintaining registration of an envelope  112  against a backstop  180 . Continuous vacuum from each of the deck strips via their respective vacuum plenums prevents any jiggling of the envelope even though the transport belts  121 ,  123  and  125  are continuously running beneath. 
         [0026]    Rotating backstop members  180  are preferably located outside the vacuum deck strips in an elongate slot. Each backstop member  180  is concentrically mounted about a common shaft  182  for effecting rotation thereof. Each stopping portion  184  is configured to stop an envelope when it is above the deck  141  of insertion station  100 . A servo motor (not shown) causes rotation of the backstops members  180  about axle  182 . 
         [0027]    Insertion station  100  includes envelope flap retainers  124  and rotating insertion horns  126  and  128  each having an underside that assists in helping an envelope conform to each transport belt  121 ,  123  and  125  while not presenting any catch points for the leading edge of the enclosure collation  130  to be inserted in a waiting open envelope  112 . The horns  126  and  128  are supported from above the envelope path and are eccentrically mounted on pivot shafts  103 . They are positioned perpendicular to the path of the envelope travel as the envelope is conveyed to backstop members  180 . Once the vacuum assembly  70  has begun to open the envelope, the insertion horns  126  and  128  can be pivoted into the envelope in a manner that will be further discussed in connection with  FIGS. 3-5 . Insertion horns  126  and  128  will move into the envelope so that the outer edges of the envelope have been shaped and supported. Rotating insertion horns  126  and  128  perform the additional function of centering envelope  112  in the path of the oncoming enclosure collation  130 . The pivot shafts of each insertion horn  126  and  128  are driven by a servo motors  104  and  105  (see  FIGS. 3-5 ). 
         [0028]    Insertion station  100  further includes an envelope opening vacuum assembly  70  for separating the back panel of an envelope from its front panel Vacuum assembly  70  is perpendicular to the transport deck  141  of insertion station  100 . Vacuum assembly  70  includes a reciprocating vacuum cup  72  that translates vertically downward toward the surface of the transport deck  141  and then upward away from the transport deck  141  to a height sufficient to allow a stuffed envelope to pass under. The vacuum cup  72  adheres to the back panel of an envelope, through a vacuum force present in vacuum cup  72  so as to separate the envelopes back panel away from its front panel during upward travel of the vacuum cup  72 . 
         [0029]    The enclosure collations  130  are fed into the insertion station  100  by means of a pair of overhead pusher fingers  132  extending from a pair of overhead belts  134  relative to the deck of inserter system  10 . As with the envelope  112 , the top side of the envelope flap retainers  124  and the associated interior of the insertion horns  126 ,  126  must not present any catch points for the leading edge of the enclosure collation  130 . 
         [0030]    Referring to  FIG. 2 , a method of operation according to an illustrative embodiment of the present application is described. An envelope  112  is conveyed to the transport deck  141  of insertion station  100  via guide path  114  (which is in connection with an envelope supply (not shown)). Once a portion of the envelope  112  contacts the continuous running transport belts  121 ,  123  and  125 , these transport belts convey envelope  112  downstream as indicated by arrow B, in insertion station  100 . Concurrently, each deck strip of transport deck  141  provides a continuous vacuum force upon envelope  112  (via vacuum plenums) so as to force envelope  112  against the continuous running transport belts  121 ,  123  and  125 . Next, an elongate stopping portion  184  of backstop member  180  is caused to extend above the transport deck  141  at a height sufficient to stop travel of the envelope  112  in insertion station  100 . The leading edge of the envelope  112  then abuts against the stopping portion  184  of backstop member  180  so as to prevent further travel of the envelope  112 . 
         [0031]    While the envelope  112  is abutting against the stopping portion  184  of backstop member  180 , the transport belts  121 ,  123  and  125  are continuously running beneath the envelope  112 . To prevent jiggling of the envelope  112  (as could be caused by the friction of continuous running transport belts  121 ,  123  and  125 ) the continuous vacuum force applied to the envelope  112  by the deck strips functions to stabilize the envelope  112  on the transport deck  141  while it is abutting against backstop member  180 . 
         [0032]    When envelope  112  is disposed in insertion station  100 , the vacuum cup  72  of vacuum assembly  70  is caused to reciprocate downward toward the back panel of envelope  112 . The vacuum cup  72  adheres to the back panel and then reciprocates upwards so as to separate the back panel from the envelope front panel to create an open channel in the envelope  112 , Enclosure collation  130  is then conveyed toward the envelope  112  by pusher fingers  132 . 
         [0033]    For purposes of the controlled insertion the pertinent components are depicted in  FIG. 3 , the significant components in which the new algorithm is employed consists of the servo controlled belts  121 ,  123  and  125  that run on top of vacuum deck  141 , and a set of servo controlled overhead pusher belts  134 . The envelope  112  is held against the vacuum deck  141  by the vacuum so it may be controlled by the associated servo for the belts  121 ,  123 , and  125 . 
         [0034]    The overhead pushers  132  convey the collation into the staged open envelope  112 . The inventive algorithm determines the exact position of the overhead pushers  30  that, when reached, should commence the acceleration of the vacuum deck belts  121 ,  123 ,  125  such that when the vacuum deck belts  121 ,  123 ,  125  reaches the same velocity of the overhead pushers  132 , the desired insertion depth is achieved. Typically, the downstream end of the collation should be in the envelope  112  with the acceleration begins, so the vacuum cup  72  can be released prior to beginning acceleration of the envelope. 
         [0035]    Since the overhead pushers  132  will experience twice the displacement of the vacuum deck belts  121 ,  123 ,  125  during the vacuum decks belts  121 ,  123 ,  125  acceleration from rest until it reaches the same velocity as the overhead pushers  132 , the point to commence this acceleration is the cycle position of the overhead pushers  132  when they are twice the distance upstream from the desired position when the velocities match and the insertion is complete. 
         [0036]    The formula for calculating the pusher location  36  for triggering acceleration of the envelope (OHP CommenceAccel ) is as follows. In this example, the envelope creaseline  35  (OHP Creaseline ) is staged at a predetermined position 0.311 m through a pusher cycle. The beginning (position 0 m) of the pusher cycle is defined to be at position  30 . “InsertionDepth” is the desired depth for inserting the collation into envelope  112 . “Velocity” is the constant velocity of the overhead pushers  132 , and the final velocity of belts  121 ,  123 ,  125  during insertion. “Acceleration” is the acceleration of belts  121 ,  123 ,  125 . 
         [0000]    
       
         
           
             
               OHP 
               Creaseline 
             
             = 
             0.311 
           
         
       
       
         
           
             
               OHP 
               CommenceAccel 
             
             = 
             
               
                 OHP 
                 Creaseline 
               
               + 
               InsertionDepth 
               - 
               
                 
                   velocity 
                   2 
                 
                 
                   2.0 
                   × 
                   acceleration 
                 
               
             
           
         
       
     
         [0037]    If the insertion depth is zero, the overhead pushers  132  and the vacuum deck belts  121 ,  123 ,  125  will match velocities when the pushers  132  are exactly at the crease line  35  of the envelope  132 , which by that time would have moved the acceleration distance downstream from the staged location. A positive insertion depth puts the document collation further into the envelope  112 , and vice-versa. The insertion is completed “on-the-fly”. 
         [0038]    The relevant measurements are now given for the preferred embodiment. As mentioned above, the OHP Creaseline  is 0.311 m from the zero starting position to the far left. The preferred insertion depth is typically around 0.008 m. Typical velocities and accelerations are 3.7 m/s and 150 m/ŝ2. Plugging these values into the formula we get a result of 0.2734 m for the OHP CommenceAccel  position  38 , as depicted in  FIG. 3 . 
         [0039]    Prior to feeding into the insert station, the crease line  35  of the envelope  112  is detected by an optical sensor, as known in the art. Subsequently, the positioning of the envelope  112  and the pusher mechanisms  132  are tracked by the respective motor encoder signals for the motors driving the overhead pusher  134  and the vacuum deck belts  121 ,  123 ,  125 . 
         [0040]    Although the invention has been described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and various other changes, or and deviations in the form and detail thereof may be made without departing from the spirit and scope of this invention.