Abstract:
A turnbar for use in a sheet accumulator having an accumulating assembly which causes sheets serially and separately entering an entry point to overlap each other to form a stack at an exit point. The turnbar is used to change the direction of the sheets at the entry point and the stack at the exit point. The turnbar can be disengaged from the accumulating assembly for jam clearance and maintenance purposes. Preferably, the turnbar has a securing mechanism for removably mounting the turnbar on the sheet accumulator.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates generally to an inserting machine for mass mailing and, more specifically, a device to cause a large number of separate cut sheets to be accumulated into individual stacks each having a number of sheets.  
         BACKGROUND OF THE INVENTION  
         [0002]    Multi-station document inserting systems are generally used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mailings where the contents of each mailpiece are directed to a particular addressee. One of the most important features of the inserting systems is speed, which is measured by the number of mailpieces that can be assembled in a given time period. A modern inserting system is expected to assemble over ten thousand mailpieces per hour. A typical inserting system includes a plurality of serially arranged stations including a sheet feeding station, a folding station and an insertion station. In general, the sheet feeder feeds one or a plurality of sheets of mailing materials to an accumulator, which collects the fed sheets into a predefined collated packet or stack. Mailing materials are usually printed on a continuous web of paper and the printed paper is cut into individual sheets. These sheets are then accumulated into individual stacks and each stack is stuffed into an envelope for mailing. One of the conventional ways of sheet accumulation is to slow down or stop the sheets in an impending accumulation (i.e., for a mailpiece) at a certain point until all the sheets have arrived. This conventional method is cumbersome and inefficient because it requires a drastic change in machine speed.  
           [0003]    As disclosed in related patent application Ser. No. 09/310,217, now issued as U.S. Pat. No. 6,273,419 sheets  100   1 ,  100   2 ,  100   3  are accumulated in an apparatus  1 , which has a plurality of paths  211 ,  212 ,  123 , . . . , connecting the entry point  2  and the exit point  4 , with each path having a different pathlength. Related U.S. Pat. No. 6,273,419 in hereby expressly incorporated by reference. The paths are so controlled that, for each stack of the sheets in an impending accumulation, a sheet entering the accumulator will travel a progressively shorter path than the preceding one. In other words, the first sheet travels a longer path than the second sheet, the second sheet travels a longer path than the third sheet, and so forth. The pathlength difference between two successive paths can be designed in accordance with the requirement in sheet stacking. If the sheets are stacked in a way that one sheet is partially overlapped with another, like the shingle pattern on a rooftop (see stack  110 , FIG. 1), then the pathlength difference between two successive paths is smaller than the length of the sheets. If the edges of the accumulated sheets in a stack are flush with each other, then the pathlength difference is substantially equal to the sheet length. For example, if only three sheets  100   1 ,  100   2 ,  100   3  are to be accumulated into a stack  110 , then sheets  100   1    100   2 ,  100   3  are separately directed to paths  213 ,  212  and  211 , respectively, as shown in FIG. 2. As shown in FIG. 2, when the sheets to be accumulated enter the entry point  2  along a path  200 , they are caused to change direction so that they can be separately directed toward different paths. As shown, the direction of incoming sheets is changed from  200  to  202 . After being accumulated, the stacked sheets are moved along path  218  and they are again caused to change direction to path  220  before exiting through the exit point  4 .  
           [0004]    As sheets are moved in high speed in and out of the accumulating apparatus  1 , jams could occasionally occur. It is advantageous and desirable to provide a way to clear the jam.  
         SUMMARY OF THE INVENTION  
         [0005]    It is an object of the present invention to provide an apparatus for sheet accumulation, wherein the sheets to be accumulated are not required to slow down significantly or pause in the accumulation process.  
           [0006]    It is another object of the present invention to provide an apparatus for sheet accumulation, wherein the apparatus can have a small footprint.  
           [0007]    It is yet another object of the present invention to provide an apparatus for sheet accumulation, which has a turnbar to change the direction of the sheets to be accumulated when the sheets are separately entering the accumulation apparatus, and the direction of the accumulated stack when the stack exits the accumulation apparatus. As such, the sheets prior to accumulation and the accumulated stack travel in the same direction. According to the present invention, the turnbar can be removed from the accumulation apparatus for jam clearance and maintenance purposes.  
           [0008]    Accordingly, the first aspect of the present invention is a sheet accumulator, which comprises:  
           [0009]    an accumulating assembly that accumulates a plurality of sheets that serially and separately enter an entry point so as to allow these sheets to overlap each other thereby forming a stack at an exit point, the accumulator having a plurality of paths connecting the entry point and the exit point with each path having a different path length, and means for controlling the paths so as to allow each sheet of said plurality of sheets to travel a different path such that a sheet entering the entry point travels a shorter path than a preceding sheet, wherein the sheets travel along a first direction prior to entering the entry point, a second direction different from the first direction after entering the entry point, a third direction different from the second direction prior to leaving the exit point, and a fourth direction different from the third direction after leaving the exit point;  
           [0010]    a removable turnbar having first means located in the proximity of the entry point for directing the sheets entering the entry points from the first direction to the second direction, and second means located in the proximity of the exit point for directing the sheets leaving the exit point from the third direction to the fourth direction.  
           [0011]    Preferably, the turnbar is operable at a first position and a second position, and wherein when the turnbar is operated at the first position, the turnbar is engaged with the accumulating assembly for directing the sheets entering the entry point from the first direction to the second direction and for directing the sheets leaving the exit point from the third direction to the fourth direction, and when the turnbar is operated at the second position, the turnbar is disengaged from the accumulating assembly to facilitate maintenance and/or jam clearance of the sheet accumulator.  
           [0012]    Preferably, the sheet accumulator further comprises a securing mechanism to prevent the turnbar from being disengaged from the accumulating assembly when the turnbar is operated at the first position, wherein the security mechanism comprises a pin on the turnbar which is engaged with a latch on the accumulating assembly.  
           [0013]    Preferably, the sheet accumulator further comprises a securing mechanism to prevent the turnbar from accidentally engaging with the accumulating assembly when the turnbar is operated in the second position, wherein the security mechanism comprises a pin on the turnbar which is engaged with a latch on the accumulating assembly.  
           [0014]    The second aspect of the present invention is a turnbar for use in a sheet accumulator having an accumulating assembly, wherein the accumulating assembly accumulates a plurality of sheets that serially and separately enter an entry point so as to allow these sheets to overlap each other and thereby form a stack at an exit point, the accumulator having a plurality of paths connecting the entry point and the exit point with each path having a different path length, and means for controlling the paths so as to allow each sheet of said plurality of sheets to travel a different path such that a sheet entering the entry point travels a shorter path than a preceding sheet, wherein the sheets travel along:  
           [0015]    a first direction prior to entering the entry point;  
           [0016]    a second direction different from the first direction after entering the entry point;  
           [0017]    a third direction different from the second direction prior to leaving the exit point; and  
           [0018]    a fourth direction different from the third direction after leaving the exit point. The turnbar comprises:  
           [0019]    a first means located in the proximity of the entry point for directing the sheets entering the entry point from the first direction to the second direction;  
           [0020]    a second means located in the proximity of the exit point for directing the sheets leaving the exit point from the third direction to the fourth direction; and  
           [0021]    a mounting mechanism for removably mounting the turnbar on the sheet accumulator.  
           [0022]    According to the present invention, the sheets are capable of leaving the exit point along the fourth direction in a first exit path or a second exit path, and the turnbar further comprises a path diverting mechanism for selecting either the first or the second path.  
           [0023]    According to the present invention, the turnbar further comprises a center bar located between a first side arm and a second side arm, wherein the first side arm has a first surface substantially parallel to the first direction for guiding the sheets to move toward the entry point, the second side arm has a second surface substantially parallel to the fourth direction for guiding the sheets to move away from the exit point, the center bar has a third surface substantially parallel to the second direction for guiding the sheets to move toward the accumulating assembly in the second direction and a fourth surface substantially parallel to the third direction for guiding the sheets to move toward the exit point in the third direction.  
           [0024]    According to the present invention, the first means may comprise a curved surface located between the first surface and the third surface for urging the sheets to move from the first direction to the second direction, and the second means may comprise a curved surface located between the second surface and the fourth surface for urging the sheets to move from the third direction to the fourth direction.  
           [0025]    According to the present invention, the sheets are capable of leaving the exit point along the fourth direction in a first exit path along the second surface or a second path spaced from the second surface, and wherein the turnbar further comprises a path diverting mechanism for selecting either the first or the second path.  
           [0026]    According to the present invention, the path diverting mechanism comprises a flipper operable at a first position to allow the sheets to reach the second curved surface and a second position protruding into the third direction to cause the sheets to move toward the second path.  
           [0027]    The present invention will become apparent upon reading the description taken in conjunction with FIGS.  3  to  6   b.    
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    [0028]FIG. 1 is a diagrammatic representation illustrating the function of a sheet accumulator.  
         [0029]    [0029]FIG. 2 is a diagrammatic representation illustrating the principle of the sheet accumulator.  
         [0030]    [0030]FIG. 3 is a cross sectional view illustrating the sheet accumulator having an accumulating assembly and a turnbar, according to the present invention, wherein the turnbar is operated in a “home” position.  
         [0031]    [0031]FIG. 4 a  is a cross sectional view of the upper portion of the sheet accumulator illustrating the turnbar being disengaged from the accumulating assembly.  
         [0032]    [0032]FIG. 4 b  is a cross sectional view of the middle portion of the sheet accumulator illustrating the turnbar being disengaged from the accumulating assembly.  
         [0033]    [0033]FIG. 4 c  is a cross sectional view illustrating the lower portion of the sheet accumulator.  
         [0034]    [0034]FIG. 5 a  is a cross sectional view illustrating a mechanism for securing the turnbar on the sheet accumulator when the turnbar is engaged with the accumulating assembly.  
         [0035]    [0035]FIG. 5 b  is a cross sectional view illustrating a mechanism for securing the turnbar on the sheet accumulator when the turn is disengaged with the accumulating assembly.  
         [0036]    [0036]FIG. 6 a  is a diagrammatic representation illustrating a first exit path of the sheet accumulator.  
         [0037]    [0037]FIG. 6 b  is a diagrammatic representation illustrating a path diverting mechanism to cause a stack of accumulated sheets to move along a second exit path. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]    Referring to FIG. 3, the sheet accumulator  10 , according to the present invention, comprises an accumulating assembly  18  and a turnbar  20  located on top of the accumulating assembly  18 . The turnbar  20  has a first side arm  40 , a second side arm  42 , and a center bar  30  located between the first and second side arms. The accumulating assembly  18  has a first top section  50  and a second top section  60  defining a gap  62  (see FIG. 4B) to engage with the center bar  30  when the turnbar  20  is mounted on the accumulating assembly for normal operation. The first side arm  40  of the turnbar  20  has one or more rollers  22 ,  24  to form an entry point  12  of the sheet accumulator with one or more rollers  52 ,  54  on the first top section  50  of the accumulating assembly  18 . The first side arm  40  and the first top section  50  further have rollers  24  and  54  to move a sheet (not shown) from the entry point  12  into the accumulating assembly  18 . As shown in FIG. 3, a curved section  32  on the left side of the center bar  30  causes the sheet to change direction, as indicated by the rightward path  200  to the downward path  202 . The curved section  32  is located between a surface  31  of the first side arm  40  and a surface  33  of the center bar  30  (see FIG. 4 a ). If four sheets (not shown) are accumulated into one stack (not shown), then the first sheet is caused to travel along the path  214 ; the second sheet is caused to travel along the path  213 ; the third sheet is caused to travel along the path  212 , and the fourth sheet is caused to travel along path  211 . The traveling paths are controlled by a plurality of flippers  191 ,  192 ,  193  and  194 . The control of the traveling paths is not part of the present invention. After the sheets have traveled past their designated paths, they travel along the upward path  218  in an overlapping manner. The stack is then caused by a curved surface  34  on the upper right side of the center bar  30  to change direction, from the upward path  218  to the rightward path  220  at an exit point  14 . The curved surface  34  is located between a surface  37  of the second side arm  42  and a surface  35  of the center bar  30  (see FIG. 4 a ). Thus, the main function of the turnbar  20  is to direct the sheets entering the entry point from the rightward path  200  to the downward path  202 , and direct the stack from the upward path  218  to the rightward path  220  at the exit point  14 .  
         [0039]    The sheet accumulator  10  has two side doors  96  and  98  for covering both sides of the accumulating assembly  18 . The side doors  96  and  98  can be swung out to a clear paper jam around any one of the paths  211 - 215 , as shown in FIG. 3. However, if the jam occurs in the path near the first top section  50  or second top section  60 , it may be quite difficult to clear the jammed sheets. Thus, it is preferable that the turnbar  20  can be separated from the accumulating assembly  18  for jam clearance and for maintenance purposes.  
         [0040]    As shown in FIGS. 4 a  to  4   c,  the turnbar  20  can be pulled upward, away from the accumulating assembly  18 , thereby exposing the gap  62 , the first top section  50  and the second top section  60 . As such, the rollers  22  and  24  are separated from the rollers  52  and  54 , making it easy to remove any sheets that are stuck near the entry point  12  or the exit point  14 . Preferably, the turnbar  20  has a securing mechanism to allow the turnbar  20  to engage with a lower latch  72  when the turnbar  20  is fully engaged with the accumulating assembly  18  in a “home” position. The same mechanism is also engaged with an upper latch  74  when the turnbar  20  is disengaged from the accumulating assembly  18 . The upper latch  74  and the lower latch  72  are shown in more detail in FIGS. 5 a  and  5   b.    
         [0041]    [0041]FIG. 5 a  shows the turnbar  20  being in the home position and the lower latch  72  in a locking position. As shown, the pin  38  is engaged with the lower latch  72 , preventing the turnbar  20  from being pulled upward. However, when the lower latch  72  is shifted to the left, as indicated by arrow  172 , to disengage the pin  38  therewith by turning the lever  70  in a clockwise direction  170 , the turnbar  20  can be pulled upward to separate it from the accumulating assembly  18 .  
         [0042]    [0042]FIG. 5 b  shows the turnbar  20  being in the disengaged position and the upper latch  74  in a locking position. As shown, the pin  38  is engaged with the upper latch  74 , preventing the turnbar  20  from being moved downward. However, when the upper latch  74  is shifted to the left, as indicated by arrow  174 , to disengage the pin  38  therewith by turning the lever  70  in a counter-clockwise direction  171 , the turnbar  20  can be pushed downward to its home position.  
         [0043]    [0043]FIGS. 6 a  and  6   b  show that at the exit point  14  of the sheet accumulator  10 , a stack of accumulated sheets (not shown) moving along path  218 , can exit along path  220  or path  220 ′. The paths are controlled by a flipper  80  operatively linked to an actuator  82 . As shown in FIG. 6 a,  the actuator  82  keeps the flipper  80  away from the roller  56 , allowing the stack to enter the nip  90  formed by a roller  26  and a roller  58 . The stack is then moved by the rollers  26  and  58  along the path  220  onto a platform  84 . In FIG. 6 b,  the actuator  82  pushes the flipper  80  to move close to a roller  56 , causing the stack to enter a nip  92  formed by a roller  57  and the roller  56 . The stack is then moved by the rollers  56  and  57  along path  220  onto a platform  84 .  
         [0044]    The removable turnbar  20 , according to the present invention, has been disclosed as having means to cause the sheets entering the entry point to change direction, as indicated by arrows  200  and  202 , and means to cause the stack exiting the exit point to change direction, as indicated by arrow  218 ,  220  and  220 . However, it is not necessary that the turnbar changes the direction of the separated sheets and the accumulated sheets at both the entry point and the exit point. Furthermore, two exiting paths  220  and  220 ′ at the exit point  14  can be alternately selected so that stacks moving along path  208  can be alternately directed to path  220  and  220 ′. However, when only one exiting path is needed, only one of the exiting paths will be selected. Thus, it is possible that the sheet accumulator has only one exiting path. Moreover, it is also possible to have more than two exiting paths.  
         [0045]    Thus, although the invention has been described with respect to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and various other changes, omissions and deviations in the form and detail thereof may be made without departing from the spirit and scope of this invention.