Patent Publication Number: US-8122845-B2

Title: Envelope flap moistener

Description:
FIELD AND BACKGROUND OF THE INVENTION 
     The invention relates to an envelope flap moistener. Envelope flap moisteners are typically used for moistening one or more strips of adhesive material such as arabic gum on a flap of an envelope prior to closing the flap in an inserting apparatus for inserting postal items into the envelope, moistening the strips on the envelope flap and closing the envelope flap. Such envelope flap moisteners typically have an envelope transport track. An envelope is transported along the envelope track such that the flap to be moistened and closed is passed along a moisture transfer member. Moisture is transferred from the moisture transfer member to the adhesive material, which becomes to some extent liquefied and sticky when water is applied thereto. Then the flap is mechanically closed and the adhesive sticks to the body of the envelope and is to some extent absorbed by the envelope body, so that a strong joint between the flap and the body of the envelope is obtained. In practice, the joint is generally so strong that the flap cannot be disconnected from the envelope body without damaging the envelope. Thus, the adhesive also constitutes a sealing material. 
     During operation of inserting apparatus, the dosage of liquid (generally simply water) should be such that the adhesive is moistened sufficiently to obtain a sufficiently strong bond between the body and the flap of the envelope, but not excessively to avoid excessive wrinkling of the envelope or even damage to the contents of the envelope. When the apparatus is operating in an essentially steady state condition, moistening a fairly constant number of envelope flaps per unit of time, providing a proper dosage of liquid is generally no problem. However, when the apparatus is started after having been out of operation for a longer period, e.g. more than an hour or several hours, it is often a problem to ensure quickly that the liquid is properly dosed as of the first envelopes of a series of mail pieces. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a simple solution to facilitate dosing amounts of liquid to be applied to envelope flaps of a series of envelopes as of the first envelopes of that series, even if the apparatus for moistening envelopes has been inactive for a prolonged period of time immediately previous to the start of closing the series of envelopes. 
     According to the invention, this object is achieved by providing an envelope moistener having a moisture transfer member for transferring liquid adhering thereto to a flap of an envelope, a support for supporting an envelope in a flap moistening position with a flap of the envelope in contact with a contact surface of the moisture transfer member, a liquid reservoir communicating with the moisture transfer member for feeding liquid to the moisture transfer member; and an encapsulation containing the moisture transfer member, the encapsulation having a cap suspended movably between a closed position and an open position and the encapsulation encapsulating at least a portion of the moisture transfer member including the contact surface when the cap is in the closed position and leaving the contact surface of the moisture transfer member exposed for allowing the contact surface to contact an envelope flap when the cap is in the open position. 
     By encapsulating at least a portion of the moisture transfer member including the contact surface from all sides when the cap is in the closed position, that portion of the moisture transfer member is fully shielded from the environment, so that evaporation of moisture is counteracted. Thus, the moisture transfer member will dry out less, so adequate amounts of liquid are dosed readily to the first flaps of a series of envelopes even if the apparatus has been out of operation for a prolonged period immediately preceding the moistening of the first envelopes of a series. 
     The cap is moreover suspended such that it leaves the contact surface of the moisture transfer member exposed for allowing the contact surface to contact an envelope flap when the cap is in the open position. Thus, the envelope flap moistener can be put into operation, without removing the cap from the apparatus. 
     Particular elaborations and embodiments of the invention are set forth in the dependent claims. 
     Further features, effects and details of the invention appear from the detailed description and the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of a side view of a first example of an apparatus according to the invention; 
         FIG. 2  is a schematic representation of a side view of the apparatus according to  FIG. 1  in a different operating condition; 
         FIG. 3  is a schematic representation of a view along the lines III-III in  FIG. 1 ; and 
         FIG. 4  is a schematic representation of a side view of a second example of an apparatus according to the invention; and 
         FIG. 5  is a schematic representation of a side view of the apparatus according to  FIG. 4  in a different operating condition. 
     
    
    
     DETAILED DESCRIPTION 
     A first example of an envelope flap moistener is described with reference to  FIGS. 1-3 . 
     A housing and support frame of the apparatus has schematically been designated by hatched portions  1 - 3 . A moisture transfer member  4  for transferring liquid adhering thereto to a flap  6  of an envelope  5  is mounted to an arm  7  that is hinged to the housing about a pivot axis  8 . The moisture transfer member  4  has a plurality of moistening brush portions  9  that are held by brush holder  10 , which is mounted to a bridge member  11  interconnecting the arms  7  on opposite side of the apparatus. The moisture transfer member  4  may also be constituted or include one or more liquid absorbing structures including small cavities for retaining and dispensing liquid, such as a sponge, felt or woven or braided elements. 
     A support for supporting the envelope  5  in a flap moistening position (see  FIG. 1 ), with the flap  6  of the envelope  5  in contact with a contact surface  12  of the moisture transfer member  4 , is constituted by a set of pressing disks  13  mounted to a pressing axis  14  which is rotatably suspended to the frame  1 - 3  and by envelope path guides  15 - 18 . 
     A liquid reservoir  19  communicates via a liquid transfer conduit  20  and a pump  21  (not shown in  FIG. 2 ) with the moisture transfer member  4  for feeding liquid to the moisture transfer member  4 . 
     For counteracting evaporation of liquid from the moisture transfer member  4 , an encapsulation containing the moisture transfer member  4  is provided. The encapsulation includes a cap  22  suspended movably between a closed position shown in  FIG. 2  and an open position shown in  FIG. 1 . In the present example, the encapsulation further includes the bridge member  11  against which a rim of the cap  22  rests when in the closed position. 
     When the cap  22  is in the closed position, the encapsulation encapsulates the brush portions  9  of the moisture transfer member  4  including the contact surfaces  12  from all sides, so that evaporation of liquid from the moisture transfer member  4 , and in particular from the contact surfaces  12  thereof is effectively counteracted. The cap  22  in the closed position covers the contact surfaces  12  of the moisture transfer member  4 , which are exposed to allow an envelope flap access thereto when the cap  22  is in its open position. 
     Depending on the extent to which counteracting evaporation is desired, the cap  22  may sealingly contact the bridge member  11  so that moisture transfer member  4  is hermetically encapsulated or leave slight gaps or slits between its rim and the bridge member  11  when in closed condition. The latter may be advantageous for facilitating opening of the cap  22  and avoiding subjecting the moisture transfer member to pressure variations and associated displacements of liquid to and from the reservoir  19  when the cap  22  is opened and closed. Preferably such gaps or slits are narrower than 1 or 2 mm, the moisture transfer member  4  otherwise being hermetically enclosed and shielded from the environment. 
     As is shown in  FIG. 1 , when the cap  22  is in the open position, it leaves the contact surfaces  12  of the moisture transfer member  4  exposed for allowing the contact surfaces  12  to contact an envelope flap  6 . In  FIG. 1 , a representation in dash-and-dot lines shows the arm  7  and the moisture transfer member  4  in a position with the contact surfaces  12  contacting an envelope flap  6 . As can be seen from  FIGS. 1 and 2 , the moisture transfer member  4  is movable between a moistening position projecting to an envelope flap position for moistening the envelope flap  6  and a retracted position retracted relative the moistening position. 
     For moving the cap  22  between the open and the closed position, a cap drive  23  is provided, which is connected to the cap  22  for moving the cap  22  between the open position and the closed position. In the example shown in  FIGS. 1-3 , the cap drive  23  includes an electric motor  24  mounted to the frame  1 - 3 , a shaft  25  drivable by the electric motor  24 , a worm wheel  26  coupled to the shaft  25  so as to rotate with the shaft  25 , a gear wheel segment  27  pivotably suspended relative to the frame  1 - 3  about a pivot axis  28  and having teeth engaging a helical profile in the circumference of the worm wheel  26 . The cap  22  is fixedly connected to the gear wheel segment  27  so that the cap  22  pivots with the gear wheel segment  27  about the pivot axis  28  when the motor  24  drives rotation of the shaft  25  about its centre line. 
     A control circuitry  29  is connected to the motor  24  for controlling the motor  24  and, accordingly, the cap drive  23 . The control circuitry  29  is arranged for controlling the cap drive  23  for causing the cap  22  to open in response to activation of the envelope flap opener for successively moistening a plurality of envelopes, for leaving the cap  22  open between moistening of the envelopes, and for causing the cap  22  to close in response to de-activation of the envelope moistener after completion of moistening the plurality of envelopes. Thus, the cap  22  closes automatically, each time a job of moistening flaps of a series of envelopes is completed or at least if the envelope moistener is switched off. Movement of the cap  22  does not interfere with operation of the apparatus while evaporation of liquid is counteracted between periods of operation in which, due to the often prolonged durations of such non-operating periods (from one to two hours to a day or more), the problem of drying out of the moisture transfer member  4  between periods of operation is most relevant. The control circuitry  29  may be connected to a control system for controlling the envelope flap moistener, of the inserter system or of a system for preparing items to be mailed for receiving signals indicating whether the system is active for processing a series of envelopes or inactive after completion of processing a series of envelopes and awaiting a command to process a next batch of envelopes. An inactive signal may also be provided if a feeder for feeding contents or envelopes is empty and the system for preparing items to be mailed is waiting for the feeding station to be reloaded. 
     To further counteract evaporation of moisture and also for reducing humidity inside an inserting station, it may be provided that the control circuitry  29  is arranged for controlling the cap drive  23  for causing the cap  22  to open each time the moisture transfer member  4  is moved to the moistening position and for controlling the cap drive  23  for causing the cap  22  to close each time the moisture transfer member  4  is moved to the retracted position. 
     In  FIGS. 4 and 5  a second example of an envelope flap moistener according to the invention is shown. 
     A housing and support frame of the apparatus has schematically been designated by hatched portions  100 - 103 . A moisture transfer member  104  for transferring liquid adhering thereto to a flap  6  of an envelope  5  is mounted to a push rod  107  that is connected to a pin  131  guided in a slot  108  in the housing. 
     A support for supporting the envelope  5  in a flap moistening position (see  FIG. 5 ), with the flap  6  of the envelope  5  in contact with a contact surface  112  of the moisture transfer member  104 , is constituted by a set of pressing disks  113  mounted to a pressing axis  114  which is rotatably suspended to the frame  100 - 103  and by envelope path guides  115 - 118 . 
     A liquid reservoir  119  communicates via a liquid transfer conduit  120  and a pump  121  with the moisture transfer member  104  for feeding liquid to the moisture transfer member  104 . The moisture transfer member  104  is mounted to a holder  110  which also bounds a chamber for holding a volume of liquid for keeping the moisture transfer member  104  moist. An overflow conduit  130  has an inlet at a level determining the level of liquid in the chamber and allows excess amounts of liquid to flow back to the reservoir  119 . The pump  121  is connected to a control circuitry  129  for receiving commands to pump liquid into the holder  110  at regular intervals, for instance each time after moistening one or a plurality of envelope flaps. 
     The moisture transfer member  104  is movable between a moistening position projecting to an envelope flap position for moistening an envelope flap  6  (see  FIG. 5 ) and a retracted position retracted relative to the moistening position (see  FIG. 4 ). For driving this movement back and forth, according to the present example, the push-rod  107  is connected to a drive unit  124  including a motor and a gear box. The drive unit  124  is mounted to the frame portion  103  and coupled to the control circuitry  129  for moving the push-rod  107  back and forth such that the moisture transfer member  104  is pushed from the retracted position to the moistening position each time an envelope flap  6  passes the pressing member  113  and is to be moistened. Thereafter, the drive unit  124  is controlled to retract the moisture transfer member  104  to the retracted position. 
     For counteracting evaporation of liquid from the moisture transfer member  104 , an encapsulation containing the moisture transfer member  104  is provided. The encapsulation includes a cap  122  suspended movably between a closed position shown in  FIG. 4  and an open position shown in  FIG. 5 . In the present example, the encapsulation further includes walls  111  bounding a passage in which the holder  110  is movable. The holder  110  rests against the surfaces of the walls  111 , such that the passage is effectively closed off. When the cap  122  is in the closed position, the cap  122 , the walls  111  and the holder  110  constitute an encapsulation of the moisture transfer member  104 , which counteracts evaporation of liquid from the moisture transfer member  104 . Depending on the extent to which counteracting evaporation is desired, the cap  122 , the walls  111  and the holder  110  may be in sealing contact or leave slight gaps or slits in-between when the cap  122  is in closed condition. Preferably such gaps or slits are narrower than 1 or 2 mm. 
     As is shown in  FIG. 5 , when the cap  122  is in the open position, it leaves the contact surfaces  112  of the moisture transfer member  104  exposed and allows the moisture transfer member  104  to be in the moistening position shown in  FIG. 5  contacting an envelope flap  6 . 
     For moving the cap  122  between the open and the closed position, the cap  122  is coupled to the moisture transfer member  104  so that the cap  122  moves to the open position when the moisture transfer member  104  moves to the moistening position and the cap  122  moves to the closed position when the moisture transfer member  122  moves to the retracted position. In the present example, this coupling is realized by a connecting bar  133  linking the pin  131  connected to the push-rod  107 , which is guided in the slot  108  to a further pin  132  coupled to the cap  122  and guided in a further slot  134  defining a direction in which the cap  122  is movable back and forth. When the pin  131  coupled to the push-rod  107  moved upwardly for driving displacement of the moisture transfer member  104  from the retracted position to the moistening position, the connecting bar  133  pushes the further pin  132  away from the moisture transfer member  104  in a direction transverse to the direction of movement of the moisture transfer member  104 , thereby retracting the cap from the closed position to the open position, leaving room for the moisture transfer member  104  to pass from the retracted position to the moistening position. When the moisture transfer member  104  moves back to the retracted position, the connecting bar  133  pulls back the further pin  132  and the cap  122  attached thereto back so that the cap  122  is displaced back to the closed position. 
     Since the cap  122  is coupled to the moisture transfer member  104  so that the cap  122  moves to the open position when the moisture transfer member  104  moves to the moistening position and the cap  122  moves to the closed position when the moisture transfer member  104  moves to the retracted position, no separate motor is needed to drive the displacements of the cap  122 . 
     It will be clear to the skilled person that within the framework of the present invention as defined by the claims, many other embodiments than the above described embodiments are conceivable. For instance, the movement of the cap between the open and the closed position may be driven or triggered by the passage of an envelope of which the flap is to be moistened and/or has been moistened. Feeding of liquid to the moisture transfer member may be realized without pumps, for instance using capillary effects and/or gravity. Furthermore, the encapsulation may be partially integrated with the reservoir. 
     Instead of Arabic gum, the adhesive to be moistened may also be another adhesive that become liquid and/or sticky when water or another solvent is applied thereto, such as a natural adhesive made from inorganic mineral sources, or biological sources such as vegetable matter, starch (dextrin), natural resins or from animals e.g. casein or animal glue.