Patent Publication Number: US-8531699-B2

Title: Item transport system with pneumatic aligner

Description:
FIELD OF THE INVENTION 
     The present invention relates to an item transport system and, more particularly, to an item transport having a pneumatic aligner. 
     BACKGROUND OF THE INVENTION 
     Inserter systems are used to create mailpieces for a range of applications. Inserters utilize a generally modular array of components to carry out the various processes associated with mailpiece creation. The processes include preparing documents, assembling the documents associated with a given mailpiece, adding any designated inserts, inserting the assembly into an envelope, and processing the stuffed envelopes. Such processing may include multiple steps, including sealing the envelopes, edge marking, applying a postage indicia, outsorting, and stacking the completed mailpieces. 
     An important feature in the operation of inserter systems is the ability to maintain a desired spacing between the assembled mailpieces as they undergo output processing, for example. Such spacing allows the various output processing devices to process a given mailpiece and then reset for a subsequent mailpiece. 
     The change in spacing between consecutive mailpieces is known as “pitch dither.” Minimizing pitch dither allows inserter systems, for example, to process mailpieces more consistently and avoid jams. For example, if the spacing between mailpieces becomes too small, the output processing devices may be unable to process all of the mailpieces. In one example, a printer may be unable to properly position an edge marking or a bar code in the same location on mailpieces in a given batch. In another example, if the spacing between subsequent mailpieces is not maintained, the mailpieces may collide, causing a jam. 
     SUMMARY OF EXEMPLARY ASPECTS 
     In the following description, certain aspects and embodiments of the present invention will become evident. It should be understood that the invention, in its broadest sense, could be practiced without having one or more features of these aspects and embodiments. It should also be understood that these aspects and embodiments are merely exemplary. 
     In accordance with the purpose of the invention, as embodied and broadly described herein, one aspect of the invention relates to an item transport system comprising an input transport for receiving items along a first transport path, an angle transport for conveying the items along a second transport path disposed at an angle with respect to the first transport path, an alignment transport for conveying the items along a third transport path disposed at approximately 90 degrees to the first transport path, and an alignment surface for engaging the items while the items are conveyed in the alignment transport. 
     The alignment transport may comprise an alignment nip comprising a driven element and an idler element for engaging opposing surfaces of the items, a manifold, a source providing pressurized gas to the manifold, and an orifice in the manifold proximate to the third transport path, wherein the idler element is disposed in the orifice. 
     As used herein, “items” include papers, documents, postcards, envelopes, brochures, enclosures, booklets, media items, including CDs, DVDs, computer disks, and/or other digital storage media, and packages having a range of sizes and materials. 
     In another aspect, the invention relates to a method of transporting items in an item transport system comprising receiving the items in an input transport along a first transport path, conveying the items in an angle transport along a second transport path disposed at an angle with respect to the first transport path, conveying the items in an alignment transport along a third transport path disposed at approximately 90 degrees to the first transport path, and engaging the items with an alignment surface while conveying the items in the alignment transport. 
     Conveying the items in the alignment transport may comprise engaging the items in an alignment nip comprising a driven element and an idler element for engaging opposing surfaces of the items, providing pressurized gas to a manifold, and disposing the idler element in an orifice in the manifold proximate to the third transport path. 
     Aside from the structural and procedural arrangements set forth above, the invention could include a number of other arrangements, such as those explained hereinafter. It is to be understood that both the foregoing description and the following description are exemplary only. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, 
         FIG. 1  is a schematic view of an inserter system utilizing an embodiment of the item transport system of the present invention; 
         FIG. 2  is a schematic view of an embodiment of the item transport system of the present invention; and 
         FIG. 3  is a side view of an embodiment of an alignment transport element of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     Embodiments of the item transport system according the invention are described with reference to certain applications in mailpiece inserter systems. It should be understood, however, that the system of the invention may be used in association with other systems configured to handle and transport items. In addition, exemplary embodiments of the invention are described in association with the processing of envelopes. It should be further understood that the system of the invention may be utilized for processing other items, as that term is defined herein. 
     A schematic view of an inserter system  10  incorporating the item transport system  12  of the invention is shown in  FIG. 1 . The illustrated exemplary inserter system  10  comprises a sheet feeder  14 , which provides pre-printed documents for processing. The documents, which may comprise bills or financial statements, for example, may be provided by the sheet feeder  14  as individual “cut sheets,” or may be cut from a spool or a fan-fold stack using a web cutter (not shown). 
     The documents next move to an accumulator  16 , where the documents for respective mailpieces are assembled and folded. The folded accumulations next move to a buffer  18 , which holds the accumulations for sequential processing. The accumulations next move to a chassis  20 . As each accumulation moves through the chassis, inserts from a plurality of feeder modules  22  are added to the accumulation. 
     The accumulations next enter an envelope insertion station  24 , where the finished accumulations are inserted into envelopes provided by an envelope hopper (not shown). 
     The stuffed envelopes move into the item transport system  12  according to the invention, where the envelopes undergo a right-angle transfer, transitioning from motion in a depthwise orientation to motion in a lengthwise orientation. The operation of the item transport system is described in more detail below. 
     The envelopes next move into the output processing module  26  for sealing and outsorting, if required. Other output processing, such as weighing, for example, may also be carried out. The envelopes then enter a printing area  28 , where markings, such as a postage indicia and/or address information, for example, are applied using a printer  30 . Finally, the completed mailpieces are deposited on a stacker  32 , comprising a conveyor, for example. 
     An embodiment of the item transport system  12  of the invention is shown schematically in  FIG. 2 , in which an item  34  (e.g., envelope) is shown at three successive positions  34 A,  34 B,  34 C, respectively, as it moves through the system  12 . The item transport system  12  in the illustrated embodiment comprises an input transport  36  for receiving items  34  along a first transport path P 1 . The item  34 A is shown on the input transport  36 . Items  34  are conveyed on the input transport  36  using an input transport element  38 . In one embodiment, the input transport element  38  comprises a belt, but other drive arrangements may be used. The input transport element  38  drives the item  34 A along the first transport path P 1 . 
     The system  12  shown in  FIG. 2  further comprises an angle transport  40  for conveying the items  34  along a second transport path P 2  disposed at an angle with respect to the first transport path P 1 . The item  34 B is shown on the angle transport  40 . In one embodiment, the second transport path P 2  is disposed at approximately 45 degrees to the first transport path P 1 . Other path arrangements may also be used. 
     Items  34  are conveyed on the angle transport  40  using an angle transport element  42 . In one embodiment, the angle transport element  42  comprises a nip having a driven roller and an idler roller aligned with the second transport path P 2 . Other numbers of nips, as well as other angle transport elements, may also be used. The driven roller may be driven using a servo motor and a controller (not shown). Other driving arrangements may also be used. 
     The item transport system shown in  FIG. 2  further comprises an alignment transport  44  for conveying the items  34  along a third transport path P 3  disposed at approximately 90 degrees to the first transport path P 1 . The item  34 C is shown on the alignment transport  44 . 
     The illustrated item transport system  12  further comprises an alignment surface  46  for engaging the items  34  while the items are conveyed in the alignment transport  44 . In one embodiment, the alignment surface  46  comprises a driven belt for engaging an edge of the items  34  to drive the items along the third transport path P 3 . 
     Items  34  are conveyed on the alignment transport  44  using an alignment transport element  48 . As shown in  FIG. 3 , the alignment transport element comprises an alignment nip  50  comprising a driven element  52  and an idler element  54  for engaging opposing surfaces of the items  34 . Four alignment nips  50  are shown in the embodiment of  FIG. 3 , but a different number of nips may also be used. In  FIG. 3  an item  34  is shown entering the first two alignment nips  50  of the alignment transport  44 . 
     In one embodiment, the driven elements  52  of the alignment nips  50  are disposed at an angle to the alignment surface  46  in order to guide conveyed items  34  toward the alignment surface  46 , while simultaneously conveying the items  34  along the third transport path P 3 . In one embodiment, the driven elements  52  of the alignment nips  50  are disposed at approximately 25 degrees to the alignment surface  46 . 
     The driven element  52  shown in  FIG. 3  comprises a driven roller. In one embodiment, the driven element  52  is driven using a servo motor and a controller (not shown). Other driving arrangements may also be used. 
     The idler element  54  comprises a relatively lightweight, substantially spherical element. In one embodiment, the idler element  54  comprises a hollow, polypropylene ball having a diameter of approximately 1.75 inches and weighing approximately 0.3 ounces. Idler elements comprising other materials and having different sizes may also be used. 
     The alignment transport element  48  further comprises a manifold  56  and a source  58  providing pressurized gas to the manifold  56 . The manifold  56  is provided with an orifice  60  proximate to the third transport path P 3 . The manifold  56  shown in  FIG. 3  comprises an orifice  60  associated with each alignment nip  50 . The idler element  54  of each nip  50  is disposed in a respective orifice  60 . 
     In one embodiment, the pressurized gas provided to the manifold  56  comprises air. Other gases may also be used. The source  58  providing pressurized gas may comprise a dedicated source, such as a blower, for example. Alternatively, the source may comprise a device for processing the items that is not associated with the item transport system  12 . For example, the pressurized gas may be provided by the exhaust side of a blower system associated with a vacuum deck transport upstream of the item transport system  12 . Gas sources associated with other upstream or downstream devices may also be used. 
     The pressure in the manifold  56  is regulated to provide a desired force on each of the idler elements  54 . In some embodiments, the idler elements  54  provide a substantially constant force on the items  34  in a direction substantially perpendicular to the third transport path P 3 . The force may be determined based on the pressure in the manifold  56  and the diameter of the idler elements  54 . In one embodiment, the pressure in the manifold  56  is regulated to approximately 0.05 pounds per square inch in order to deliver approximately 2 ounces of force to each idler element  54  having a diameter of approximately 1.75 inches. 
     In the illustrated embodiment, each orifice  60  has a substantially circular shape and receives a respective idler element  54  having a substantially spherical shape. As shown in  FIG. 3 , the maximum diameter of the idler element  54  is less than the diameter of the orifice  60 . In one example, idler elements  54  having a diameter of approximately 1.75 inches are disposed in respective orifices  60  having a diameter of approximately 1.76 inches. The resulting gap around the idler element allows the gas to leak around the idler element. 
     In operation, as an item enters an alignment nip, the item forces the idler element laterally to the downstream side of the respective orifice, creating a gap  62  on the upstream side of the orifice  60 .  FIG. 3  shows an item  34  in the alignment transport  44  that has entered the first two alignment nips  50 . The upstream gaps  62  for those alignment nips are shown in  FIG. 3 . 
     The relatively high air leak rate in the gaps  62  creates a region of low pressure in accordance with Bernoulli&#39;s equation applied to compressible air flow. The low pressure region produces a self-centering, restoring force on the idler elements  54 . The use of air to load the idler elements  54  and, in particular, the restoring force on the idler elements  54  will reduce rolling friction in the system and may provide a smoother transition of items  34  between the alignment nips  50 . 
     In addition, the relatively low mass of the idler elements  54  and the constant force provided by the air flow may help maintain the idler elements  54  in contact with items  34  being conveyed. Accordingly, the item transport system  12  of the present invention may minimize the pitch dither of items  34  undergoing output processing, thereby increasing the system&#39;s reliability. In some embodiments of the item transport system  12 , the pitch dither was reduced to +/−9 milliseconds from +/−23 milliseconds, which had been achieved with conventional devices. 
     The operation of the item transport system  12  in transporting an item  34  will be described with reference to  FIG. 2 . 
     The item  34 A is initially received in the input transport  36  from an upstream component along the first transport path P 1 . Next, the item  34  is conveyed in the angle transport  40  along a second transport path P 2  disposed at an angle with respect to the first transport path P 1 . The item  34  is then conveyed in an alignment transport  44  along a third transport path P 3  disposed at approximately 90 degrees to the first transport path P 1 . Finally, the item  34  is engaged with an alignment surface  46  while being conveyed in the alignment transport  44 . 
     In one example, in order to process 26,000 items per hour in the item transport system, the items are conveyed in the direction of the third transport path P 3  at a velocity of 100 inches per second. The various transport elements are run at particular speeds in order to maintain the velocity component of the items along the third transport path P 3 . 
     In the case where the second transport path P 2  is disposed at approximately 45 degrees to the first transport path, the angle transport element is run at (100 inches per second)*(cosine 45 degrees)=141 inches per second. Further, in the case where the driven elements of the alignment nips are angled at approximately 25 degrees to the alignment surface, the driven rollers of the alignment transport element are driven at (100 inches per second)*(cosine 25 degrees)=110 inches per second. Lastly, in systems where the alignment surface comprises a driven belt, the driven belt, which is aligned with the third transport path P 3 , is driven at 100 inches per second. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure and methodology described herein. Thus, it should be understood that the invention is not limited to the examples discussed in the specification. Rather, the present invention is intended to cover modifications and variations.