Abstract:
An inserter system includes a pre-fold accumulator subsystem in which plural sheets are collected before folding and insertion into an envelope. A divert gate is at the upstream side of the pre-fold accumulator to selectively downwardly divert sheets fed in a reverse direction from the pre-fold accumulator. Positioning of the divert gate is controlled by a mechanism that couples the divert gate and a drive shaft that drives a sheet drive belt component of the pre-fold accumulator.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention disclosed herein relates generally to paper handling equipment, and more particularly to a folder and inserter system for assembling mail pieces. 
       BACKGROUND 
       [0002]      FIG. 1  is a front elevational view of a conventional inserter system  100 . As seen from  FIG. 1 , the inserter system  100  includes a control panel  102 , and several sheet feeder towers  104  arranged along a sheet transport path  106 . Each sheet feeder tower  104  may, for example, include two or more sheet feeders that hold and contain feed trays for paper sheets and inserts. The sheets are fed from the sheet feeders along the sheet transport path to a pre-fold accumulator  108 . In the case of at least some mail pieces to be assembled by the inserter system  100 , two or more sheets are accumulated to form a collation, which is then fed downstream to a folder  110 . 
         [0003]    The inserter system  100  also includes an envelope feeder  112 . Envelopes are fed from the envelope feeder  112  to an insertion station  114 , at which each folded collation is inserted into a respective one of the envelopes. Sealing and metering of the resulting mail pieces may be performed downstream from the inserter system  100 , in a mailing machine which is not shown. 
         [0004]      FIGS. 2A and 2B  schematically illustrate operation of a divert gate  202  positioned upstream from the pre-fold accumulator  108 . Also schematically shown in  FIGS. 2A and 2B  is a sheet transport mechanism  203  that transports paper sheets in a downstream direction (indicated by arrow  204  in  FIG. 2A ) to the pre-fold accumulator  108 . The pre-fold accumulator  108  includes one or more drive belts (discussed further below, not separately shown in  FIGS. 2A and 2B ) which drive the sheets toward a pre-fold accumulator gate (not separately shown). Until the collation of sheets is complete, the pre-fold accumulator gate blocks the sheets so that they are held in the pre-fold accumulator  108 . 
         [0005]    On occasion, a collation is too large to be folded by the folder  110 . In such a case, it is necessary to outsort the collation from the fold/insertion transport path. This is accomplished in cooperation with the divert gate  202 , in a manner schematically illustrated in  FIG. 2B . As shown in  FIG. 2B , the oversize collation (not shown) is fed in a reverse or upstream direction (indicated by arrow  206 ) by the drive belt(s) (not separately shown), such that the oversize collation contacts the divert gate (in its open position shown in  FIG. 2B ) and is diverted downwardly (as indicated by arrow  208 ) out of the normal feed path. 
         [0006]    According to a previously proposed arrangement, the divert gate  202  is biased by a spring (not shown) towards the open position shown in  FIG. 2B . A stop (which is not shown) limits the upward movement of the divert gate  202  to define the open position. During normal feeding of a sheet from the sheet transport mechanism  203  toward the pre-fold accumulator  108 , the sheet pushes downwardly against the divert gate  202  against the force of the spring to push the divert gate  202  to its closed position (shown in  FIG. 2A ) to allow the sheet to be fed to the pre-fold accumulator  108 . Once the sheet clears the divert gate  202 , the spring pushes the divert gate  202  back to the open position shown in  FIG. 2B  to allow for outsorting/diverting of the collation, if necessary. 
         [0007]    There are potential problems with the spring-driven divert gate arrangement, as described above. For example, the spring must provide enough force to reliably return the divert gate  202  to its open position, yet not so much force that the divert gate  202  fails to close when a sheet is fed in the downstream direction over the divert gate  202  from the upstream transport. In practice, it has been difficult to arrive at a suitable amount of spring force. In some cases, the spring selected has provided too much force, and as a result, in the case of a relatively light sheet, the divert gate may fail to close upon downstream feeding of the sheet against the divert gate, resulting in the sheet crashing upwardly against the system frame (not shown) and failing to reach the pre-fold accumulator. However, if the spring force were to be reduced, the response time in opening of the divert gate may not be rapid enough for desired operation of the inserter system. 
       SUMMARY 
       [0008]    According to an aspect of the invention, an inserter system includes a sheet transport mechanism for transporting a sequence of sheets in a downstream direction. The inserter system further includes a sheet accumulator subsystem, located in the downstream direction from the sheet transport mechanism. The sheet accumulator subsystem is for receiving and accumulating the sheets transported by the sheet transport mechanism. The sheet accumulator subsystem includes a drive belt and a drive shaft engaged with the drive belt at an upstream end of the drive belt. The drive shaft selectively drives the drive belt in a forward direction and a reverse direction. The drive belt is for driving one or more of the sheets in the downstream direction when the drive belt is driven in the forward direction by the drive shaft. The drive belt is also for driving one or more of the sheets in an upstream direction when the drive belt is driven in the reverse direction. The upstream direction is opposite to the downstream direction. 
         [0009]    According to this aspect of the invention, the inserter system also includes a divert gate located in the upstream direction relative to the drive belt. The divert gate is pivotally mounted at an upstream end of the divert gate. The divert gate has a downstream end that is movable between an upper position and a lower position. The divert gate is located relative to the drive belt such that the divert gate downwardly diverts one or more of said sheets when the downstream end of the divert gate is in the upper position and the drive belt is driven in the reverse direction. The inserter system further includes a coupling mechanism for coupling the divert gate to the drive shaft to impart force from the drive shaft to the divert gate for pivotally moving the divert gate to shift the downstream end of the divert gate between the lower position and the upper position. 
         [0010]    The coupling mechanism may include a linkage connected to the divert gate and a friction clutch carried on the drive shaft and connected to the linkage. 
         [0011]    When the drive shaft rotates in a first rotational direction to drive the drive belt in the forward direction, the coupling mechanism couples torque from the drive shaft to the divert gate to shift the downstream end of the divert gate from the upper position to the lower position. When the drive shaft rotates in a second rotational direction (opposite to the first rotational direction), the coupling means couples rotational force from the drive shaft to the divert gate to shift the downstream end of the divert gate from the lower position to the upper position. 
         [0012]    The friction clutch may include a collar fixed to the drive shaft to rotate with the drive shaft, a first bushing slidably confronting the collar, a second bushing, and a coil spring between the first and second bushings for biasing the first bushing into contact with the collar. 
         [0013]    According to another aspect of the invention, a method includes driving a drive belt in a forward direction by rotational motion of a drive shaft in a first rotational direction, with the drive belt driving at least one sheet in a downstream direction. The method further includes driving the drive belt in a reverse direction by rotational motion of the drive shaft in a second rotational direction, where the reverse direction is opposite to the forward direction, and the second rotational direction is opposite to the first rotational direction. The drive belt drives the at least one sheet in an upstream direction while the drive belt is driven in the reverse direction. The method further includes coupling the drive shaft to a divert gate to shift the divert gate from a closed position to an open position in response to the drive shaft rotating in the second rotational direction, and downwardly diverting the at least one sheet by driving the at least one sheet by the drive belt into contact with the divert gate when the divert gate is in the open position. 
         [0014]    The coupling step may include engaging the drive shaft with a friction clutch that is connected to the divert gate. The method may further include coupling the drive shaft to the divert gate to shift the divert gate from the open position to the closed position in response to the drive shaft rotating in the first rotational direction. 
         [0015]    According to still another aspect of the invention, an improvement is provided in an inserter system. The inserter system includes a sheet transport mechanism, a sheet accumulator that includes (a) a drive belt for receiving paper sheets from the sheet transport mechanism and for driving the paper sheets and (b) a drive shaft for driving the drive belt. The inserter system further includes a divert gate for diverting downwardly paper sheets driven in an upstream direction by the drive belt. The improvement includes a coupling mechanism for converting rotational force of the drive shaft into pivotal force for pivoting the divert gate between a closed position and an open position. 
         [0016]    In accordance with these aspects of the invention, the divert gate is actuated in response to forward or reverse rotation of the accumulator belt drive shaft, thereby closely and reliably coordinating positioning of the divert gate with operation of the accumulator drive belt. 
         [0017]    Therefore, it should now be apparent that the invention substantially achieves all the above aspects and advantages. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Various features and embodiments are further described in the following figures, description and claims. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0018]    The accompanying drawings illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain the principles of the invention. As shown throughout the drawings, like reference numerals designate like or corresponding parts. 
           [0019]      FIG. 1  is a front elevational view of an inserter system in which the present invention may be applied. 
           [0020]      FIGS. 2A and 2B  schematically illustrate operation of a divert gate that is a component of the inserter system of  FIG. 1 . 
           [0021]      FIGS. 3A and 3B  schematically illustrate an arrangement, provided in accordance with aspects of the present invention, by which the divert gate shown in  FIGS. 2A and 2B  is actuated in response to operation of an accumulator belt drive shaft that is part of the pre-fold accumulator subsystem of the inserter system of  FIG. 1 . 
           [0022]      FIG. 4  shows details of the actuating mechanism that couples the accumulator belt drive shaft to the divert gate. 
           [0023]      FIG. 5  is a sectional view that schematically illustrates details of a friction clutch that is part of the actuating mechanism shown in  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    In accordance with aspects of the present invention, a divert gate positioned just upstream from a pre-fold accumulator in an inserter system is actuated for movement between open and closed positions via a linkage coupled to the drive shaft for the sheet drive belt(s) of the accumulator. When the drive shaft rotates in a direction for causing the drive belt to drive sheets in the downstream direction, the linkage converts shaft rotation into an actuation force to move the divert gate to its closed direction. When the drive shaft rotates in a direction for causing the drive belt to drive sheets in the upstream direction, the linkage converts shaft rotation into actuation force to move the divert gate to its open position for downwardly diverting the upstream driven sheets. 
         [0025]      FIGS. 3A and 3B  schematically illustrate an arrangement, provided in accordance with aspects of the present invention, by which the divert gate (reference numeral  202   a  in  FIGS. 3A and 3B ) is actuated in response to operation of an accumulator belt drive shaft that is part of the pre-fold accumulator subsystem  108  of the inserter system.  FIG. 4  shows details of the actuating mechanism  302  that couples the accumulator belt drive shaft to the divert gate in accordance with aspects of the present invention. The features shown in  FIGS. 3A ,  3 B and  4  may be incorporated into the inserter system environment described above with reference to  FIGS. 1 ,  2 A and  2 B. Except for the manner in which it is controlled, the divert gate  202   a  of  FIGS. 3A ,  3 B and  4  may be the same, and provide the same functionality, as the divert gate shown in  FIGS. 2A and 2B . Moreover, apart from the coupling to the divert gate  202   a,  as described herein, the pre-fold accumulator  108  may be substantially conventional in its structure and functioning. (A more detailed example of an inserter system in which the invention may be applied is described in U.S. Pat. No. 7,427,059, which is incorporated herein by reference. Moreover, other example inserter systems in which the invention may be applied are commercially available from Pitney Bowes Inc., the assignee hereof, as the DI900/DI950 series.) 
         [0026]    In particular, the pre-fold accumulator  108  (also referred to as a sheet accumulator subsystem) may be located downstream from the sheet transport mechanism  203  ( FIGS. 2A ,  2 B) and may receive and accumulate sheets transported toward the pre-fold accumulator  108  by the sheet transport mechanism  203 . The pre-fold accumulator  108  includes one or more drive belts, schematically illustrated at  304  in  FIGS. 3A and 3B . The drive belt  304  is for driving sheets received by the pre-fold accumulator  108  from the sheet transport mechanism  203 . The drive belt  304 , in turn is driven by a drive shaft  306  ( FIG. 4 ) which is engaged with the drive belt  304  at an upstream end  308  ( FIG. 3A ) of the drive belt  304 . (In  FIGS. 3A ,  3 B, the drive shaft is obscured from view by the friction clutch  310 , which rides on the drive shaft  306  and which is described below.) When the drive shaft rotates in the rotational direction indicated at  312  in  FIG. 3A , the drive belt  304  is driven in a forward direction (arrow  314 ) to drive a sheet or sheets in the downstream direction of the inserter system  100 . When the drive shaft rotates in the rotational direction indicated at  316  in  FIG. 3B , the drive belt is driven in a reverse direction (arrow  318 ) to drive a sheet or sheets in the upstream direction of the inserter system  100 . It will be noted that the reverse direction  318  of the drive belt  304  is opposite to the forward direction  314  of the drive belt  304 , and the rotational direction  316  of the drive shaft  306  is opposite to the rotational direction  312  of the drive shaft  306 . 
         [0027]    The pre-fold accumulator  108  may also include idler rollers, etc. The drive shaft may be driven by a conventional motor, which is not shown. The motor may be controlled by a conventional control circuit, also not shown. 
         [0028]    Noting again that the divert gate  202   a  itself is substantially conventional, and referring to  FIGS. 3A ,  3 B and  4 , the divert gate  202   a  includes an upstream end  320  and a downstream end  322 . The upstream end  320  of the divert gate  202   a  is pivotally mounted, via a pivot  324  to the frame (not shown) of the inserter system  100  or to other mechanical ground. The downstream end  322  of the divert gate  202   a  is movable (by pivoting of the divert gate  202 a) between an upper position ( FIG. 3B ) and a lower position ( FIG. 3A ). The upper position of the downstream end  322  of the divert gate  202   a  corresponds to the open position of the divert gate  202   a;  the lower position of the downstream end  322  of the divert gate  202   a  corresponds to the closed position of the divert gate  202   a.  The upper and lower positions of the downstream end  322  of the divert gate  202   a  may be defined by respective stops (not shown) which limit the upward and downward motion of the downstream end  322  of the divert gate  202   a.  Relative to the reverse feed path of the pre-fold accumulator  108 , as illustrated in  FIG. 2B , the divert gate  202   a  may be located (when in the open position) in the same manner as the divert gate  202  shown in  FIG. 2B . 
         [0029]    In addition to the sheet transport mechanism  203 , the pre-fold accumulator  108  and the divert gate  202   a,  the inserter system  100  also includes the above-mentioned actuating mechanism  302 , which is provided in accordance with aspects of the present invention. A function of the actuating mechanism  302  is to couple the divert gate  202   a  to the drive shaft  306  so that force from the drive shaft  306  is imparted to the divert gate  202   a  to shift the downstream end  322  of the divert gate  202   a  between the positions shown respectively in  FIGS. 3A and 3B . The actuating mechanism  302  includes the above-mentioned friction clutch  310 , and a linkage  325  that is connected both to the divert gate  202   a  and to the friction clutch  310 . 
         [0030]      FIG. 5  is a sectional view that schematically illustrates details of the friction clutch  310 . As before, reference numeral  306  indicates the drive shaft. The friction clutch  310  includes a generally cylindrical collar  502  which is fixed to the drive shaft  306  for rotation with the drive shaft. The friction clutch  310  further includes a bushing  504  which rides on the drive shaft  306  in such a manner as to be slidable on the drive shaft  306 . The bushing  504  is adjacent to and confronts the collar  502 . The bushing  504  is flanged at  505  ( FIG. 4 ) to allow the linkage  324  to be connected to the bushing  504 . 
         [0031]    Still further, and continuing to refer to  FIG. 5 , the friction clutch  310  includes a bushing  506  which is adjacent to a portion  508  of the frame of the inserter system. The bushing  506  also rides on the drive shaft  306 . It will be appreciated that the drive shaft  306  may be mounted in the frame, which serves as mechanical ground for the friction clutch  310 . Alternatively, mechanical ground for the friction clutch  310  may be provided by the inner race of a ball bearing for mounting the drive shaft  306 . The ball bearing race enclosure may alternatively be considered to be represented by component  508  in  FIG. 5 . 
         [0032]    In addition, the friction clutch  310  includes a coil spring  510 , which rides on the drive shaft  306  between the bushings  504 ,  506 . The spacing of the bushings  504  and  506  and the dimensions of the coil spring  510  are such that the coil spring  510  is held in compression and therefore exerts a biasing force on the bushing  504  to bias the bushing  504  into frictional contact with the collar  502 . Steel washers  512  may be provided to interface the coil spring  510  to the bushings  504 ,  506 . 
         [0033]    It may be the case that the pre-fold accumulator is unchanged from a conventional design except perhaps for a small increase in the torque provided by the accumulator belt drive shaft. 
         [0034]    In operation, the rotational direction of the drive shaft  306  controls the position of the divert gate  202   a  via the actuating mechanism  302 . Let it first be assumed that the divert gate  202   a  is in the open position ( FIGS. 3B ,  2 B) and that the next step to be performed is feeding of a sheet from the sheet transport mechanism  203  into the pre-fold accumulator  108 . To receive the sheet and feed it to the above-mentioned accumulator gate (not shown), the drive shaft  306  is rotated in the direction  312  shown in  FIG. 3A , to drive the drive belt  304  in the forward direction  314 . Because of frictional engagement between the collar  502  and the flange bushing  504 , flange bushing  504  rotates together with the drive shaft  306  and the collar  502 . The linkage  325  ( FIGS. 3A ,  4 ) translates the rotational motion of the drive shaft  306 , the collar  502  and the flange bushing  504  into pivotal motion to pivot the divert gate  202   a  from its open position shown in  FIG. 3B  to its closed position shown in  FIG. 3A . The response time of the divert gate  202   a  relative to the beginning of rotation of the drive shaft  306  may be quite rapid, on the order of 15 milliseconds. 
         [0035]    The feed path  204  shown in  FIG. 2A  is now clear to allow transport of the incoming sheet from the sheet transport mechanism  203  into the pre-fold accumulator  108 . The drive shaft  306  continues to turn, continuing to drive the drive belt  304  in the forward direction to drive the sheet to the accumulator gate (not shown). The pivoting motion of the divert gate  202   a  is stopped at the closed position, and thus the flanged bushing  504  is prevented by the linkage  325  ( FIG. 4 ) from rotating with the drive shaft  306 /collar  502 , and the flanged bushing therefore slips on the drive shaft  306 , while remaining in slipping contact with the collar  502 . 
         [0036]    Next let it be assumed that a collation of sheets (not shown) held in the pre-fold accumulator  108  is to be outsorted via the path shown in  FIG. 2B . It is assumed that the divert gate  202   a  is in the closed position shown in  FIG. 3A . The drive shaft  306  is rotated in the direction  316  shown in  FIG. 3B , to drive the drive belt  304  in the reverse direction  318 . The frictional engagement between the collar  502  and the flange bushing  504  causes the flange bushing  504  to rotate with the drive shaft  306  and the collar  502 . The linkage  325  translates the rotation motion of the drive shaft  306 , the collar  502  and the flange bushing  504  into pivotal motion to pivot the divert gate  202   a  from its closed position shown in  FIG. 3A  to its open position shown in  FIG. 3B . The response time of the divert gate  202   a  is rapid enough to open the divert gate  202   a  before the reverse-driven collation reaches the divert gate  202   a.  The collation is driven into the divert gate  202   a  by the drive belt  304  and diverted downwardly by the divert gate  202   a,  as illustrated in  FIG. 2B . The drive shaft  306  continues to turn with the divert gate  202   a  in the open position as the reverse driving of the collation is completed. While this takes place, the pivoting motion of the divert gate  202   a  is stopped at the open position, such that the linkage  325  prevents the flanged bushing  504  from rotating with the drive shaft  306 /collar  502 . Again the flanged bushing  504  slips relative to the drive shaft  306  and the collar  502 . 
         [0037]    With the divert gate actuating mechanism described above with reference to  FIGS. 3A-5 , the short-comings of a spring-loaded divert gate may be avoided, and reliable operation of the divert gate achieved, at low cost. 
         [0038]    In addition or as an alternative to the function of the divert gate in regard to outsorting reverse-fed over-sized collations, the divert gate may perform a function relative to preventing or minimizing jamming of sheets upon entry into the pre-fold accumulator  108 . According to this function, before an additional sheet is fed into the pre-fold accumulator  108 , one or more sheets already present in the pre-fold accumulator  108  are driven a short distance upstream by the drive belt, and the upstream (relative to normal feed direction) edge of the reverse driven sheets is slightly downwardly diverted by the divert gate  202   a  (which is opened to a limited extent) to allow the new sheet to be fed into the pre-fold accumulator  108  while clearing the upstream edge of the sheets already in the pre-fold accumulator  108 . 
         [0039]    The words “comprise,” “comprises,” “comprising,” “include,” “including,” and “includes” when used in this specification and in the following claims are intended to specify the presence of stated features, elements, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, elements, integers, components, steps, or groups thereof. 
         [0040]    A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Other variations relating to implementation of the functions described herein can also be implemented. Accordingly, other embodiments are within the scope of the following claims.