Abstract:
An apparatus for stacking articles on edge is provided which has a discharge magazine for stacking the articles face-to-face and on-edge. The magazine has an article edge receiver having a non-offset position and an offset position. The article edge receiver has a register wall for aligning the articles in the non-offset position and a segmented rotational offset disk for aligning the articles in the offset position. The disk has a cut out segment having a planar stop edge surface. The cut out segment is rotatable from an article receiving position to an article bypass position. When in the receiving position, the planar stop edge surface is at a right angle to the two faces of the article. When in the article bypass position, the segmented rotational offset disk allows the articles to bypass the segmented rotational disk.

Description:
CROSS REFERENCES TO RELATED APPLICATION 
     This application is a Continuation-In-Part Application of U.S. application Ser. No. 10/091,196, filed Mar. 5, 2002, which is a Continuation of U.S. application Ser. No. 09/561,506, filed Apr. 28, 2000 now U.S. Pat. No. 6,398,204. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to mass mail handling equipment. More particularly, this invention relates to an improved apparatus for taking a series of flat articles such as envelopes, orienting them, and then stacking the articles in groupings. 
     In the high volume mail industry, in both U.S. First Class and Third Class mail, envelopes are filled with various letter pieces using automated mail inserters. For example, U.S. Pat. Nos. 5,029,832 and 5,211,384 disclose an in-line inserter device having envelope and feeding assemblies, an envelope inserting station, a sealing and stacking assembly, and various diverter stations. 
     Mass-mailing equipment has become very diverse in its functions. For instance, inserting equipment transports envelopes along an inserting track while various types of inserts are automatically inserted into the envelopes. The envelopes are normally transported to another piece of equipment that automatically seals the envelopes, weighs them and affixes postage. Still additional equipment automatically reads the zip codes or zip code indicia on the envelopes and indicates zip code breaks in the envelope groups for zip code presorting. This allows the user to take advantage of lower postage rates. Other mass-mailing equipment may include remittance processing equipment and zip code sorting equipment. 
     Customers utilizing mass-mailing equipment may have differing needs and requirements. Therefore, mass-mailing equipment is generally designed for one specific function. Each piece can then be connected by conveyor or other transport means to additional mail processing equipment so that a customized system can be assembled. One problem with this approach is that adjacent mail processing equipment may require the envelopes to be oriented in a position which is different from the discharge device of the preceding equipment. This necessitates transition conveyors or re-orientation devices. 
     For example, most mail processing inserting equipment in use today moves the envelopes along a track with their faces (the addresses) face down and the flaps extended with the back of the flaps up during the insertion mode. The envelopes, as they leave the inserting machine, may have the flaps moistened and sealed before exiting the inserting machine. If the envelope is then going to have postage applied, it must be turned over 180 degrees so that the postage can be affixed to the face of the envelope. Other operations may require the envelope to be turned 90 degrees. 
     One such stacking apparatus is disclosed in U.S. Pat. No. 4,705,157. Here, a device is disclosed for turning envelopes 90 degrees as the envelopes are moved forward through the device from an entrance location to an exit location using two endless belts adjacent to one another. The envelopes are ultimately stacked once they leave the exit location. 
     Currently, many inserters simply eject the filled envelope onto a short flat conveyor, allowing the envelopes to free float on the conveyor. This causes the possibility that the zip order of the envelopes will get mixed up, the possibility of envelopes becoming disorderly and difficult to quickly pick up, and the possibility of envelope flaps popping opened prior to proper glue drying. Additionally, this method is an inefficient use of conveyor space, allowing only a short amount of time before the conveyor becomes full. This requires the increased attention from an operator. Often, an operator is forced to shut down the entire machine so that he or she can catch up with the emptying of the conveyor. Obviously, this drastically reduces the overall throughput of envelopes. 
     These mail inserters may run at speeds, for example, from several hundred filled envelopes per hour to approximately 18,000 envelopes per hour. These speeds have created a need on the end of the inserters to collect the filled envelopes in such a way as to allow the operator to load them into mail trays or other forms of storage quickly and efficiently. In addition, since these envelopes are often prearranged in special zip code order, this order must be maintained by the operator and then separated into different trays depending on these zip code groupings. 
     This area has proven to be the “bottleneck” of the mail insertion process. Many times, the operator has a difficult time keeping up with the inserter. Additionally, the envelopes are not presented in such a way that the zip code breaks can be read easily. The operator may develop fatigue, possibly even carpal tunnel syndrome, because of excess handling of envelopes. One means to assist here is the inclusion of an envelope stacking apparatus at the end of the system to secure the sorted mail pieces in a stacked position to facilitate the orderly removal of the processed mail pieces from the system. 
     One area of difficulty with envelope stacking apparatus is the high likelihood of jamming and high complexity of various apparatus presently available. For example, one method used to handle envelopes after inserting, as provided in U.S. Pat. No. 4,903,955, is a conveyor that turns the envelopes on edge and horizontally stacks them using a wire auger, in the form of an enlarged corkscrew. Shortcomings of this method include the requirement for a complex algorithm to keep an open part of the auger exposed to the incoming envelope in addition to a possible short life of a spring clutch used to turn the auger. 
     U.S. Pat. No. 4,705,157 provides an article turning apparatus for turning envelopes to an on-edge position and discharging those envelopes for stacking on a conveyor. Two belts receive an envelope in a horizontal position and turn it ninety degrees to an on-edge position. This patent also discloses a segmented roller that assists in stacking the envelopes vertically. However, here, the segmented roller turns continuously and the segmented roller is adapted to strike the surface of the last discharged envelope to create a pulsing force. This system does not prevent the jamming of an incoming envelope. 
     U.S. Pat. Nos. 5,485,989 and 5,201,504 do handle higher speed inserters and offset the stack at a zip break. However, the conveyors disclosed in these patents are complex and costly and require that the zip break signal be given to it via electronic communication from the inserter. 
     PCT Serial No. PCT/93/02731 discloses an apparatus for stacking sheet like articles having a discharge magazine that includes conveyor belts and a document stop element for receiving articles on edge. A sensing means indexes the conveyor belts to allow envelopes to be stacked on a magazine. 
     One feature of many on-edge stacking conveyors is the ability to offset the registered edge of a horizontal envelope stack so as to easily identify the zip code change or count to the offloading operator. This is typically accomplished by a printing, such as a zip code, bar code, optical mark, etc., on the envelope, read by an electronic reading device, as the envelope enters the on-edge stacking apparatus. This data is then used to index an offsetting device that causes the front perimeter edge of the envelope stack to create an offset from the envelopes previously received in the stack. That is, a series of envelopes is first stacked against a register wall. When a new zip code break is read, the offset device causes new envelopes to offset by a small amount. The result is an indexed stack with zip code breaks easily identified. In present systems, after a set of envelopes has been offset by the offset device and a new zip code break is read, the next set of envelopes coming in no longer is required to be offset. However, the first incoming envelope of a new set may drag the prior, offset, envelope back to the register wall due to frictional drag. This occurs particularly when the offset device is withdrawn too soon. This may be overcome by delaying, for example, via software, the moment when the parallel wall of the offset device is retracted to several inches before the new envelope gets to the offset device. This solution is only partially successful because the retraction of the offset device must be started early because the front lip of the offset must be clear before the new envelope passes it. Because there are still several inches of travel for the incoming envelope, there is still some frictional drag of the prior envelope. 
     Accordingly, it would be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles on edge which overcomes the disadvantages of the prior art. 
     It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that operates at high speed. 
     It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that operates without jamming. 
     It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that provides a means to separate different groups of the articles. 
     It would still further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that re-orients from a flat position to an upright, on-edge position. 
     It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that does not require an operator to shut down the apparatus on a regular basis so that the operator can catch up with the emptying of the stacked articles. 
     It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that does not require a complex algorithm to operate causing potential jamming and failure of the apparatus. 
     It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that provides a means to offset a horizontal envelope stack to mark zip code changes. 
     It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that maintains pressure on the envelopes in the stack to allow time for the flap glue to dry. 
     It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge where the articles are moved from a flat position to a horizontal position, either clockwise or counterclockwise using a single belt. 
     Many other attendant features of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     A stacking apparatus for stacking a plurality of flat articles on edge is provided. Each article has a front perimeter edge and two faces. The stacking apparatus receives each of the flat articles as each article enters the stacking apparatus moving in a direction generally parallel to the faces of each article. The stacking apparatus includes a discharge magazine for sequentially receiving and stacking the flat articles face-to-face in an on-edge stack. The discharge magazine includes an article inlet and an article edge receiver. The article edge receiver includes a non-offset position and an offset position. In either the offset position or the non-offset position, the front perimeter edge contacts the article edge receiver to align the front perimeter edge of each article as the articles enter the stack. The discharge magazine further includes an article face receiver wherein a face of one of the flat articles abuts the article face receiver. The article edge receiver has a register wall, wherein when the article edge receiver is in the non-offset position, each front perimeter edge contacts the register wall to align the front perimeter edge of each article. The article edge receiver also has a segmented rotational offset disk to provide the offset position. The segmented rotational offset disk has a rotational axis and at least one cut out segment where the cut out segment has a planar stop edge surface parallel to the rotational axis. The cut out segment is rotatable from an article receiving position to an article bypass position. When the cut out segment is in the article receiving position, the planar stop edge surface is at substantially a right angle to the two faces of the article and the planar stop edge surface is adapted to receive the front perimeter edge of each article. When the cut out segment is in the article bypass position, the article edge receiver is in the non-offset position such that the segmented rotational offset disk allows the front perimeter edge of each article to bypass the segmented rotational disk. 
     The article face receiver is preferably moveable along a conveyor to provide additional space, as required, for articles while providing a compressive force to the stack of articles. 
     A continuously rotating additional roller adjacent the segmented roller may be included to assist in driving each article to the article edge receiver. 
     The article stack offsetter may be adapted to offset the articles at specific article counts. 
     The article stack offsetter may be adapted to offset the articles when an electronic signal is received. 
     Preferably, the cut out segment is pie-shaped. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     Other objects and many attendant features of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
     FIG. 1 is an isometric view of an on-edge stacking apparatus in accordance with one preferred embodiment of the present invention; 
     FIG. 2 is a top view of a belt turn-up mechanism as used in the on-edge stacking apparatus of FIG. 1; 
     FIG. 3 is a partial top view of the on-edge stacking apparatus of FIG. 1 depicted without an envelope stack; 
     FIG. 4 is a partial top view of the on-edge stacking apparatus of FIG.  1 . depicted with an envelope stack and a single envelope entering the envelope stack with a segmented roller in its home position and an envelope engaging the segmented roller; 
     FIG. 5 is a partial top view of the on-edge stacking apparatus of FIG.  1 . depicted with an envelope stack and a single envelope entering the envelope stack showing the segmented roller during rotation; 
     FIG. 6 is a partial top view of the on-edge stacking apparatus of FIG.  1 . depicted with an envelope stack with the segmented roller in its home position awaiting an envelope; 
     FIG. 7 is a partial top view of the on-edge stacking apparatus of FIG. 1 depicted with an envelope stack and showing an envelope offset device in an extended position such that the envelope stack is offset to indicate a zip code break; and 
     FIG. 8 is a partial top view of the on-edge stacking apparatus of FIG. 1 depicted with an envelope stack and showing an envelope offset device in a retracted position, subsequent to the offset device being in an extended position, such that an additional zip code break is shown. 
     FIG. 9 is a top view of an alternate discharge magazine for use in an on-edge stacking apparatus in accordance with a second preferred embodiment of the present invention, depicting a rotational offset disk in an article non-offset position. 
     FIG. 10 is a top view of the alternate discharge magazine of FIG. 9 depicting the rotational offset disk in an article offset position. 
     FIG. 11 is a is a top view of the alternate discharge magazine of FIG. 9 depicting the rotational offset disk in the article non-offset position where an offset set of envelopes is shown indicating, for example, a zip code break. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the various figures of the drawing wherein like reference numbers refer to like parts throughout the several views, there is shown in FIG. 1 an on-edge stacking apparatus  10 , for stacking articles such as envelopes, in accordance with one preferred embodiment of the present invention. The on-edge stacking apparatus  10  comprises several major components: a belt turn-up mechanism  20  (see FIG.  2 ), a discharge magazine  40  (see FIG.  3 ), an article stack offsetter  60 , and an article stack conveyor  80 . Each of these components may operate individually, or in combination with the other components of the system. Each is discussed in detail below. 
     As can be seen in FIGS. 1 and 2, the on-edge stacking apparatus  10  of the present invention uses a belt turn-up mechanism  20  to turn a generally flat article such as an envelope  12  from flat to on-edge. The unique design of the belt turn-up apparatus allows use of a single belt  22 . This belt turn-up mechanism  20  can be set up to either turn the envelope  12  clockwise or counterclockwise simply by re-threading the belt over existing pulleys  24  in the system. The entrance  26  to the belt turn-up apparatus  20  offers an area to mount an electronic reading device that can detect a zip code break mark on the incoming envelope. 
     As can best be seen in FIGS. 3-8, once the envelope  12  is on edge, the envelope  12  is transferred through the discharge magazine  40  onto a conveyor  80 , usually about 6 to 8 feet long, and inserted into the rear of an envelope stack  100 . The discharge magazine  40  takes a series of on-edge envelopes  12  and aligns them to be stacked. The discharge magazine  40  utilizes a novel segmented roller  42  in which a segment is removed such that the generally cylindrical segmented roller  42  has a flat, planar surface  44  that is perpendicular to the longitudinal axis of the segmented roller  42 . As can be seen in FIG. 4 where a first envelope  12  is entering the discharge magazine  40 , as the envelope  12  enters the article inlet  46  of the discharge magazine  40 , the segmented roller  42 , stationary in its home position, maintains a gap  48  for the first envelope  12  to enter. The flat, planar surface  44  of the segmented roller  42  acts as a guide to the incoming envelope  12 . If the flat, planar surface  44  of the segmented roller  42  was not there, the incoming envelope  12  would crash into the roller. As soon as the first incoming envelope  12  (and each succeeding incoming envelope  12 ), approaches the segmented roller  42  and enters the gap  48 , the segmented roller  42  indexes 360 degrees and then stops to assist in driving the first envelope  12  to start the horizontal stack  100  and then stacks each succeeding envelope  12  behind the first envelope (now  12 A; see FIG. 1) into the stack  100 . As can be seen in FIG. 4, the stack  100  is formed and the gap  48  formed by the flat, planar surface  44  of the segmented roller  42  on each rotation continues to be maintained for each successive envelope  12 . FIG. 5 depicts an envelope  12  in the process of being moved by the segmented roller  42  against a register wall  52 , as described below. Here, the segmented roller  42  has rotated approximately 135 degrees. FIG. 6 shows the segmented roller  42  back in its home position awaiting the next envelope to enter. 
     Preferably, as depicted in FIG. 1, the segmented roller  42  is formed in three sections. This decreases the mass of the roller to allow for easier incremental driving of the roller  42 . 
     In addition to the segmented roller, there is optionally a second continuously rotating roller  50  which is an assist drive roller that runs continuously and assures that the incoming envelope is driven to an article edge receiver, for example, in the form of a register wall  52 , where the front perimeter edges  14  of envelopes  12  are aligned for stacking. 
     As indicated above, after rotating the 360 degrees, the segmented roller  42  stops and holds in its home position, awaiting the next envelope  12 . As can be seen particularly clearly in FIG. 1, a face  16  of the first envelope  12 A entering to form the stack  100  mates with an article face receiver  54  in the form of a movable upright support member provided to hold the first envelope  12 A and the succeeding envelopes  12  upright in an on-edge position. As each successive envelope  12  enters the stack  100  and the stack  100  increases in size, the article face receiver  54  may be incrementally moved along a conveyor  80 , either manually or as described below, to allow additional room for a large stack  100  or envelopes  12 . 
     Optionally, mounted on the discharge magazine  40  is a conveyor sensor, preferably a pressure sensitive stack switch  82  which is used to sense the pressure of the horizontal envelope stack  100  against the article face receiver  54 . When pressure due to a large number of envelopes in the stack  100  causes the switch to trip, a horizontal conveyor belt on the conveyor  80  indexes to relieve this pressure, thereby making room for the next envelope or series of envelopes  12  to enter. 
     As best can be seen in FIGS. 7 and 8, another optional feature of the on-edge stacking conveyor is the ability to offset the registered edge of the horizontal envelope stack  100  so as to easily identify the zip code change or count to the offloading operator. This is accomplished by, for example, a printing (zip code, bar code, optical mark, etc.) being read onto the envelope  12  by an electronic reading device as the envelope  12  enters the on-edge stacking apparatus. This data is then used to index an article stack offsetter, for example, article stack offsetter  60 , as shown in FIGS. 6-8. The article stack offsetter  60 , as shown, may be a cylinder having an electronically controlled shaft that moves in a longitudinal direction, to cause the front perimeter edge  14  of the envelope stack  100  to include an offset  62  from the envelopes  100  previously received in the stack. When a new zip code break is read, the offsetter  60  retracts, causing new envelopes to move to the register wall  52 . That is, a series of envelopes is first stacked against a register wall  52 . When a new zip code break is read, the offsetter  60  causes a plurality of new envelopes  100  to offset by a small amount. The result is an indexed stack with zip code breaks easily identified, thereby saving significant time unloading the envelopes  12  into mail trays. 
     After a set of envelopes has been offset by the offsetter  60  and a new zip code break is read, the next set of envelopes coming in no longer is required to be offset. However, the first incoming envelope of the new set of envelopes may drag the prior, offset envelope back to the register wall  52  due to frictional drag. This occurs particularly when the offsetter  60  is withdrawn too soon. This may be overcome by delaying, for example, via software, the moment when the shaft of the offset device is retracted to several inches before the new envelope gets to the offsetter  60 . This solution is only partially successful because the retraction of the offsetter  60  must be started early because the front lip of the shaft of the offsetter  60  must be clear before the new envelope passes it. Because, due to the desired speed at which the system operates, there are still several inches of travel for the incoming envelope against the envelope stack  100 , there is still some frictional drag of the prior envelope. 
     As shown in the alternate embodiment of an on-edge stacking apparatus 10 ′ of FIGS. 9-11, a novel rotational offset disk  102 , limits this problem. For convenience, elements similar to that described with respect to the stacking apparatus  10  of the first embodiment are not described again here with respect to the stacking apparatus  10 ′ of the second embodiment. The rotational offset disk  102  is a disk having a “stop edge”  104  which is preferably a planar surface, parallel to the axis of rotation  103  of the offset disk  102 , provided by a cut out  106 , preferably pie-shaped, in the rotational offset disk  102 . The stop edge  104  of the rotational offset disk  102  is located adjacent to the register wall  52 ′ and is rotatable, preferably in a clockwise direction, away from the first incoming envelope of a new set of envelopes and therefore, does not have to start rotating until the first incoming envelope is almost upon it. Frictional drag on the preceding envelope is thereby minimized. The rotational offset disk  102  may be rotatable by an offset disk drive belt  108  connected to, for example, a motor  110 . 
     The rotational offset disk  102  operates as follows. First, as can be seen in FIG. 9, a series of envelopes  12 ′ (or other flat objects) enters the discharge magazine  40 ′ of the stacking apparatus  10 ′ and is indexed to the register wall  52 ′. As shown in FIG. 10, when the stacking apparatus  10 ′ receives a signal to offset a series of envelopes, the rotational offset disk  102  rotates one hundred eighty degrees (preferably clockwise) and stops such that the stop edge  104  is blocking the envelope path. Finally, as shown in FIG. 11, when the stacking apparatus receives a signal to offset again, the rotational offset disk  102  rotates one hundred eighty degrees (clockwise or counterclockwise) so that the envelope path is clear to the register wall. The offset envelopes caused by the rotational offset disk  102  are clearly shown here. 
     The motor  110  for the rotational offset disk  102  can be actuated, for example, utilizing stepper motor technology. A stepper motor would likely offer improved control and response time for a more precise operation over that of, for example, a solenoid. 
     Without further elaboration, the foregoing will so fully illustrate our invention that others may, by applying current or future knowledge, readily adopt the same for use under various conditions of service.