Abstract:
Inserter for inserting postal items into envelopes, wherein an envelope catcher separates the envelopes and transports the envelopes away from the stack of empty envelopes and the envelopes are subsequently transported further with the initially leading flap end trailing. The envelope catcher is suspended for movement and drivable along a catcher path, of which at least a section extends closely along the envelope to be separated. When the envelope is transported away from the envelope catcher with its flap end trailing the flap is folded open.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority from Dutch Patent Application No. 05077638.4 filed Nov. 18, 2005. 
   TECHNICAL FIELD AND BACKGROUND ART 
   The claimed invention relates to an inserter and a method for inserting postal items into envelopes. 
   Inserters generally perform several functions such as separating and transporting of individual envelopes and documents, opening envelope flaps and inserting documents into the envelopes. Such machines are relatively complicated and accordingly costly and occupy a large amount of space. 
   In U.S. Pat. No. 1,050,476, an inserter for inserting postal items into envelopes having an envelope body and a flap linked to the envelope body via a fold is disclosed. This inserter includes a hopper for holding a stack of envelopes with an outer envelope in a separating position oriented in a separating plane, with the flap, folded against or oriented at an acute angle to the envelope body on the outside of the stack of envelopes. An envelope catcher is suspended for movement and drivable along a catcher path, of which a section extends closely along the separating plane, with a free edge leading for engaging an envelope in the separating position at the inside of the fold linking the flap to the envelope body and entraining the caught envelope, with the envelope body trailing the fold, along a trajectory away from the envelope hopper towards an inserting position. To bring the envelope body in the inserting position, so that documents can be inserted therein from a postal item transport path leading to the inserting position, the envelope body is pivoted over 270°. After the envelope has been filled, the envelope is pivoted back over 270° and subsequently pushed off the envelope catcher and transported further with the fold between the envelope body and the flap leading. A disadvantage of such an inserter is its limited capacity in terms of numbers of envelopes that can be processed per unit of time and the complex structure that is required to swing the envelopes out of the transport path and back, both over 270°. 
   SUMMARY 
   It would be advantageous to provide a simple solution that allows envelopes separated from a stack by a catcher engaging in a fold between the flap and the envelope body to be transported to a hopper at a higher rate. 
   According to the disclosed embodiments, an inserter is provided for inserting postal items into envelopes including an envelope body and a flap linked to the envelope body via a fold, the inserter including:
         a hopper for holding a stack of envelopes with an outer envelope in a separating position oriented in a separating plane, with the flap, folded against or oriented at an acute angle to the envelope body on the outside of the stack of envelopes;   an envelope catcher suspended for movement and drivable along a catcher path, of which at least a section extends closely along the separating plane, with a free edge leading for engaging an envelope in the separating position at the inside of the fold linking the flap to the envelope body and entraining the caught envelope, with the envelope body trailing the fold, along a trajectory from the separating position to an end position for holding an envelope in a position for receiving postal items therein;   a transport path from the end position to the inserting post for transporting the envelope with the fold between the flap and the envelope body trailing the envelope body; and   a postal item transport path leading to an inserting post for transporting postal items to be inserted into the envelope at the inserting post.       

   Also according to the disclosed embodiment, a method is disclosed for inserting postal items into envelopes, the envelopes each including an envelope body and a flap linked to the envelope body via a fold, including:
         holding a stack of envelopes with an outer envelope in a separating position oriented in a separating plane, with the flap folded against or oriented at an acute angle to the envelope body, on the outside of the stack of envelopes;   moving an envelope catcher along the separating plane with a free leading edge leading, the envelope catcher engaging each of the envelopes in the separating position at the inside of the fold linking the envelope&#39;s flap to the envelope&#39;s body;   the catcher entraining caught envelopes, with the envelope body trailing the fold, from the separating position to an end position;   transporting envelopes from the end position to an inserting position with the fold between the flap and the envelope body trailing the envelope body;   folding open the envelope flap during transport from the end position to the inserting position;   holding envelopes in a position for receiving postal items therein; and   transporting postal items to be inserted into the envelope held in the inserting position.       

   By providing a transport path from the end position to the inserting post for transporting the envelope with said fold between the flap and the envelope body trailing the envelope body, the envelopes are disengaged from the catcher in a simple manner, the end position is catcher does not need to lead the envelope all the way the inserting position and does not need to stay there during insertion of documents, so that the catcher becomes available for separating a next envelope at a relatively early stage. 
   Particular embodiments of the invention are set forth in the dependent claims. 
   Further aspects, effects and details of the invention are set forth in the detailed description with reference to examples of which some are shown in the schematic drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic cut-away side view of a first example of an inserter according to an aspect of the invention; 
       FIGS. 2A and 2  B are schematic side views of a portion including an envelope hopper of the inserter according to  FIG. 1  in successive operating phases; 
       FIG. 3  is a schematic cut-away perspective view from below of a portion including a catcher drive, an end position and a nip of an envelope transport track of the inserter according to  FIGS. 1 and 2 ; 
       FIGS. 4A and 4B  are schematic side views of a portion including an envelope catcher of a second example of an inserter according to an aspect of the invention in successive operating phases; 
       FIGS. 5A and 5B  are schematic side views of a portion including an envelope catcher of a third example of an inserter according to an aspect of the invention in successive operating phases; 
       FIGS. 6A to 6D  are schematic side views of a portion including an envelope hopper, an envelope catcher and a transport track of a fourth example of an inserter according to an aspect of the invention in successive operating phases; 
       FIGS. 7A to 7D  are schematic side views of a portion including an envelope hopper and an envelope catcher of a fifth example of an inserter according to an aspect of the invention in successive operating phases; 
       FIGS. 8A and 8B  are schematic side views of a portion including an envelope hopper, an envelope catcher and a transport track of a sixth example of an inserter according to an aspect of the invention in successive operating phases; and 
       FIGS. 9A and 9B  are schematic side views of a portion including an envelope hopper, an envelope catcher and a transport track of a sixth example of an inserter according to an aspect of the invention in successive operating phases. 
   

   DETAILED DESCRIPTION 
   A housing  2  of the inserter  1  shown in  FIGS. 1-4  has a front side  3  and a backside  4 . At the front side  3 , a document tray  5 , a mail piece tray  6  and a hopper tray  7  are situated. The document tray is for holding documents to be inserted, the mail piece tray  6  under the document tray  5  is for receiving mail pieces (filled envelopes)  6 , and the hopper tray  7  under the mail piece tray  6  includes a hopper  8  for holding a stack of envelopes  11 . 
   Within the housing  2  and projecting therefrom at the backside  4  of the housing  2 , an inserting post  10  is situated for holding an envelope in a position for receiving postal items therein. 
   A postal item transport path for transporting documents to an inserting post  10  extends from the document tray  5  to the inserting post  10  and comprises a branch formed between the folding rollers  12 ,  13  ending in a buckle chute  14 . A free space next to the buckle chute  14  allows the formation of a loop  46  in a document  45  to be folded when the document abuts a stop in the chute and is transported further by the rollers  12 ,  13 . After folding, the folding rollers  12 , 13 , a guide  47  and insert rollers  48  deliver the folded document  45  or documents to the inserting post  10 , already holding an envelope with its flap open and held between central roller  35  and transport roller  49 . After the document or documents have been inserted into the envelope, the envelope is transported from the inserting post  10  to the mail piece tray  6 . During transport the envelope is closed. Structures for the insertion of documents as well as for the closing of envelopes are disclosed in more detail in applicant&#39;s Dutch patent applications 1027933, 1027937 and 1027940. 
   The hopper  8  is arranged for holding a stack  11  of envelopes, with one outer envelope  17  in a separating position  15 . The envelopes are of the type with an envelope body  18  and a flap  19  connected via a fold  20  to the envelope body  18 , as best seen in  FIG. 2 . The stack of envelopes  11  in the present example is situated in a vertical configuration with the outer envelope  17  being the lowermost envelope of the stack  11  in a separating position  15  at the bottom of the stack  11 . The body  18  of the envelope  17  in the separating position  15  rests against an abutment  33  and the rest of the stack  11  on top of the lowermost envelope  17 , is also, although indirectly, supported by the abutment  33 . All the envelopes in the stack  11  are lying with their flap  19  towards the separating position  15 , the flap  19  of the lowermost envelope  17  being located on the outside of the stack and hanging free since this part of the envelope  17  is not supported by the abutment  33 . 
   The abutment  33  defines a separating plane  16  against which the body  18  of the envelope  17  in the separating position  15  lies. 
   Below the stack of envelopes  11 , an envelope catcher  21  is situated. In the present embodiment, the envelope catcher  21  is wedge-shaped. If the envelope catcher  21  is in the starting position near the envelope body  18  as shown in  FIG. 1 , a free edge  23  of the envelope catcher  21  points towards the fold  20  linking the flap  19  to the body  18  of the envelope  17  in the separating position  15 . 
   The envelope catcher  21  is mounted to a belt  52  tensioned over end pulleys  53 ,  54 . If the pulleys are rotated, the catcher  21  is moved along a catcher path  24  of which a section extends closely along the separating plane  16 , and closely along the envelope  17  in the separating position  15 . In one direction of movement, the free edge  23  of the catcher  21  is leading for engaging the envelope  17  in the fold  20  linking the flap  19  and the envelope body  18  and entraining the caught envelope  17 , with the envelope body  18  trailing the fold  20 , along a trajectory from the separating position  15  to an end position  29  spaced from the envelope hopper  8 . A first guide  27  extends closely below and along the envelope catcher path  24 , for preventing the flap  19  of the envelope  17  from opening beyond an acute angle relative to the envelope body, so that the envelope catcher  21  reliably engages and entrains the envelope  17 . 
   To counteract that the envelope catcher  21  entrains more than one envelope at a time, a threshold  9  below the separating plane  16  and accordingly below the stack  11  of envelopes  17  is provided closely at the side of the envelope hopper  8  and of the stack  11  of envelopes facing in the direction of transport from the separating position  15  to the end position  29 . In this example, this threshold is formed by an edge  9  of the envelope hopper  8  protruding below the separating plane  16  and accordingly below the stack  11  of envelops. 
     FIG. 2  A illustrates how, in operation, before engagement by the envelope catcher  21 , an envelope  17  may be located in the separating position  15  and  FIG. 2B  illustrates how the envelope  17 , after engagement by the envelope catcher  21 , may be entrained past the threshold  9 . The envelope catcher  21  is pivotably suspended, such that its free edge  23  can shift to and away from the separating plane  16 . Cam  25  (see also  FIG. 3 ) define cam tracks  26  extending along the catcher path  24  and a cam follower  28  (see  FIG. 2A ) fixed for pivotably entraining the catcher  21 , cause the free edge  23  of the envelope catcher  21  to shift such that, after engaging the envelope  17 , and before passing the threshold  9 , the free edge  23  of the envelope catcher  21  shifts downward and pulls the portion of the envelope adjacent the fold between the envelope flap  19  and the envelope body downwards (i.e. in stacking direction away) from the stack of envelopes  11  while the envelope is also pulled along in the general direction of movement of the catcher  21  along the transport path  24 . The free edge  23  of the envelope catcher  21  stays in the position shifted downward at least until it has passed the adjacent edge  9  of the hopper  8 . Thus, the fold  20  of the envelope  17  is urged down beyond the threshold  9 , thereby allowing the envelope body  18  to pass the threshold  9 . A next envelope of the stack  11 , of which the fold between the flap and the envelope body is not urged downward and is therefore reliably held back by the threshold  9 . 
   The envelope catcher  21  has a support surface  22  that faces the separating plane  16  when the envelope catcher  21  is in a portion of the catcher path  24  that extends along the separating plane  16 . In operation, the support surface  22  supports the envelope body  18  during transport by the envelope catcher  21 . 
   As is best seen in  FIGS. 1 and 3 , while reaching the end position  29 , the catcher  21 ′ turns into an orientation in which its support surface  22  is approximately in-line with the transport path  32 . This causes the envelope body  18 ′ to be pivoted into an orientation in the transport path  32 . In  FIG. 1 , a succession of positions of the catcher  21  close the end position  21 ′ is shown in dash and dot lines. When the envelope  17  is transported from the end position  29  to the inserting post  10  the envelope body  18  is leading the fold  20  and the flap  19 . 
   Near the end position  29  the catcher path  24  is curved away from the separating plane  16 . A resilient abutment  30  is located at the end of the catcher path  24  and near the end position  29 . In operation, the catcher  21  presses the envelope  17  against the abutment, thereby causing the envelope  17  to be held between the abutment  30  and the free edge  23  of the envelope catcher  21  in the area of the fold  20  between the envelope flap  19  and the envelope body  18 . This ensures that the tilting of the support surface  22  of the envelope catcher  21  reliably causes the envelope  17  to swing into the transport path  32  leading to the inserting post  10 . An upper guide  31  along the transport path  32  is provided for guiding the envelope body  18  in the correct direction to a nip between the rollers  34 ,  35  ( FIGS. 1 and 3 ). 
   In this example, the resilient abutment  30  is formed by a band  30 . When the catcher is in the end position  29 , the abutment  30 , is locally displaced by the fold  20  of the envelope  17 , which in turn was pressed against the abutment  30  by the free edge  23  of the catcher  21 ′, against the action of a spring  55 . After the envelope  17 ′ has changed orientation and is positioned in the transport path  32 , the envelope catcher  21 ′ returns along the path  24  to its starting position. This causes the tensioned abutment  30  to spring back, thereby pushing against the fold  20  of the envelope  17 ′ and causing the envelope  17 ′ to be pushed into the transport track  32  with the envelope body  18  leading the fold  20 , until the envelope body  18  is urged into a nip  36  between transport rollers  34 ,  35  that then take over the further transport of the envelope  17 ′ towards the inserting post  10 . 
   When the transport rollers  34 ,  35  take over the transport of the envelope  17 ′ and the fold  20  is free from the abutment  30 , band  30 ,the flap  19  is pulled around the envelope catcher  21  so that it is opened to an extent that is sufficient to ensure that, when passing the transport rollers  34 ,  35  towards the inserting post  10 , the flap  19  is trailing the body  18  of the envelope  17 . The envelope  17  arrives in the inserting post with the flap  19  fully trailing the envelope body. 
   A control unit  50  is connected to the drive structure for controlling the driving of the transport rollers  34 ,  35  and the rollers  53 ,  54 . A sensor  51  is arranged along the transport path  32  for registering that the envelope body  18  at the end of the catcher path  24  has been turned to a position in the transport path  32 . The control unit  50  is arranged for changing the sense of rotation of the pulleys  53 ,  54  in response to an envelope being detected by the sensor  51 , thereby causing the envelope catcher  21  to return from its end position  29  to a starting position upstream adjacent the holder  8 . 
   Since the envelope catcher  21  engages the envelope in the fold between the envelope flap  19  and the envelope body  18 , it is not necessary to grip the envelope flap and a propensity of gripping surfaces to cause stains when gripping a stationary envelope during movement is avoided. Also, the envelope is engaged on a surface that is on its inside after closing, so that the engagement cannot cause staining on the outside at all. 
   It will be clear to the skilled person, that within the framework of invention as set forth in the claims also many variations other than the examples described above are conceivable. 
   For instance, as shown in FIGS.,  4 A and  4 B, instead of a separate, stationary guide  27  for limiting opening the flap  19  of the envelope  17 , a two-part envelope catcher  421  may be provided, which closes when engaging the envelope  417 . The catcher  421  has a clamping part  441 . This clamping part  441  can be guided by for example a cam track (not shown) from a position further away, to a position along the envelope catcher  421  when engaging the envelope flap  419 . Thus, a movable guide limits the opening of the envelope flap. Since the envelope flap need not be clamped between the two parts of the catcher  421  to entrain the envelope, it is reliably ensuring that the flap  419  will not slip during transport and staining caused by such slipping of a clamped envelope is avoided. 
   Another example of a movable envelope flap guide is shown in  FIGS. 5A and 5B . In this embodiment, the envelope catcher  521  is provided with a guide  527  that is connected to the catcher  521 , such that moves along with the catcher  521 . Therefore, there is no need for a guide extending along the catcher path  524 . Since the guide  527  is spaced from the envelope catcher  521 , an envelope flap can enter between the catcher  521  and the guide  527  and be pulled out from between the catcher  521  and the guide  527  after it has reached the end position without having to move the guide  527  relative to the catcher  521 . 
   In yet another embodiment shown in  FIGS. 6A to 6D , instead of an envelope catcher  21  mounted to a belt and movable along a path which is essentially straight in the vicinity of the hopper  8  and the stack  11 , a catcher wheel  621  is provided which is equipped with catchers  641 ,  642  mounted to its circumference for movement along a circular path. The catcher wheel  621  is positioned between the hopper  608  containing the stack of envelopes  611  with the envelope  617  in the separating position  615  and a transport path  632 . 
   When the catcher wheel  621  rotates in a clockwise sense, the catcher  641  engages an envelope  617  positioned in the separating position  615  at the inside of the fold  620  connecting the flap  619  to the envelope body  618 . The envelope  617  is then pulled away from between the rest of the stack of envelopes  611  and the abutment  633 . The envelope  617  partially bends around the catcher wheel  621  until the trailing edge of the envelope  617  has passed the threshold edge  609  of the hopper  608 . The envelope  617  then falls onto the transport path  632 . The distance between the catcher wheel  621  and the transport path  632  is larger than the distance between the catcher wheel  621  and the separating position  615 . Therefore, once the envelope  617  has dropped onto the transport track  632 , the free edge of catcher  642  is no longer engaging the envelope  617  in the fold  620  but further away from the envelope body. The catcher  642 , still engaging a part of the flap, is still moving in the clockwise direction while the transport path  632  moves the envelope  617  in the opposite direction. This causes the envelope flap to fold open. To ensure transport of the envelope along the transport track  632 , one or more clamping rollers or belts may press the envelope  617  against the rollers forming the underside of the transport track  632 . 
   Yet another example of an inserter according to the invention is shown in successive stages of operation in  FIGS. 7A-7D . Two envelope catchers  741 ,  742  are attached to a belt or chain that is tensioned over end pulleys as shown in  FIGS. 1 and 3 . The envelope catchers  741 ,  742  are movable along a circulating catcher path  724 . When the catchers  741 ,  742  circulate in a clockwise sense, each time the catchers  741 ,  742  pass an envelope in the separating position  717 , the respective one of the catchers  741 ,  742  engages a next one of the envelopes  717  in the separating position at the inside of the fold connecting the flap to the envelope body. The envelope  717  is then pulled away from between the rest of the stack of envelopes  711  and the support on which the stack rests. The envelope  717  swings around the turning point of the catcher path  724  ( FIG. 7B ) and then falls onto the transport path  732 . The distance between the catcher path  724  and the transport path  732  is larger than the distance between the catcher path  724  and the separating position. Therefore, once the envelope  717  has reached a position in the transport track  732 , the free edge of catcher  741  or  742  is no longer engaging the envelope  717  in the fold but further away from the envelope body (see  FIG. 7C ). The catcher  741  or  742 , still engaging a part of the flap, is still moving in the clockwise direction while the transport path  732  moves the envelope  717  in the opposite direction. This causes the envelope flap to fold open ( FIG. 7C ). To ensure transport of the envelope along the transport track  732 , clamping rollers  761  are provided for pressing the envelope  717  against the rollers forming the underside of the transport track  732 . 
   An extra advantage of the embodiments shown in the  FIGS. 6  A-D and  7  A-D in which at least two catchers circulate along the separating position, is that while a first envelope catcher is still engaged in an envelope positioned in for example the transport path, a second envelope catcher can already engage the next envelope in the separating position. 
   In  FIGS. 8A and 8B , yet another variant for the envelope supply is shown. In this example, the separating position  815  is at the top of the stack of envelopes  811 . A lift  860  is provided for keeping the topmost envelope of the stack  811  in the separating position  815  closely to the catcher path  824  as the height of the stack  811  decreases during feeding of envelopes from the stack  811 . Along the catcher path  824 , a guide  827  for limiting opening of the flap  819  of the envelope  817  extends. When the envelope catcher  821  has entrained the envelope  817  over such a distance that the trailing edge of the envelope body  818  has become free from the edge  809  of the hopper  808 , gravity causes the envelope body  818  to swing down to a vertical position oriented towards a nip between a pair of transport rollers  834 ,  835 . As the catcher  821  moves along a downwardly oriented last section of the catcher path  824 , the former trailing edge of the envelope  817  now forms a lowermost, leading edge, and the envelope  817  is lowered into the nip  836  between the transport rollers  834 ,  835 . When the transport rollers  834 ,  835  engage the envelope  817 , the envelope  817  is pulled down causing the envelope flap  819  to be folded open about the envelope catcher  821 . 
   In the embodiment shown in  FIGS. 9A and 9B , the hopper  908  and the stack  911  of envelopes has in principle the same configuration as in the embodiment shown in  FIGS. 8  A and B, the separating position  915  being at the top of the stack in an approximately constant position, the stack  911  being lifted by a lift  960  as the height of the stack  911  decreases. However, in this example, the transport path  932  is oriented at an angle upward from the path along which the catcher  921  is movable. Accordingly the nip between rollers  934 ,  935  of the transport path  932  is located higher than the path along which the catcher  921  is movable. Under the path along which the catcher  921  is movable, a lifter  938  is located for lifting an envelope  917  that has been entrained by the catcher  921  upward to an orientation directed towards the nip between rollers  934 ,  935 . 
   In operation, after separation from the stack  911 , the envelope body  918  is urged by a plunger  938  into the transport path  932 , the envelope  917  pivoting about the envelope catcher  921 . As in the embodiment shown in  FIGS. 1-4 , the envelope is held pressed against the envelope catcher  921  by a resilient abutment  930 . When the envelope catcher  921  moves back from its end position, the abutment  930  pushes envelope  917  with its body  918  leading into the nip  936 . The transport rollers  934 ,  935  then transport the envelope  917  towards an end position, whereby the flap  919  of the envelope  917  is folded open about the free edge  923  of the envelope catcher  921 . 
   Many other examples are possible within the framework of the invention as set forth in the claims, for instance an embodiment with the stack of envelopes in a horizontal configuration, the provision of a slit instead of a threshold for preventing more than one envelope passing through at a time, or fingers or grippers for a mechanical or pneumatic retaining of the stacked envelopes not yet to be transported.