Patent Publication Number: US-9902192-B1

Title: System and method for high-speed insertion of envelopes

Description:
RELATED APPLICATIONS 
     This application is a divisional of copending U.S. application Ser. No. 12/857,702, filed Aug. 17, 2010, entitled SYSTEM AND METHOD FOR HIGH-SPEED INSERTION OF ENVELOPES, the entire disclosure of which is herein incorporated by reference, which application is a divisional of copending U.S. application Ser. No. 12/204,773, filed Sep. 4, 2008, entitled SYSTEM AND METHOD FOR HIGH-SPEED INSERTION OF ENVELOPES, issued on Aug. 17, 2010 as U.S. Pat. No. 7,775,015, the entire disclosure of which is herein incorporated by reference, which claims the benefit of U.S. Provisional Application Ser. No. 60/969,912 entitled SYSTEM AND METHOD FOR HIGH-SPEED INSERTION OF ENVELOPES, by H. W. Crowley, filed Sep. 4, 2007, the entire disclosure of which are expressly incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to high-speed envelope inserters used for high-volume mailing operations. 
     BACKGROUND OF THE INVENTION 
     Current estimates place the number of envelopes used annually in the United States at over 100 billion. A significant percentage of these envelopes are used in connection with bulk mailings, and are accordingly filled, addressed and processed by a variety of automated devices. A lynchpin of all automated processes is the automatic envelope inserter. Automatic inserters are large, complex devices that are loaded with contents to be inserted (e.g., individual letter sheets and/or fillers) and envelopes in which these contents are to be inserted. Other devices such as binders, that bind inserts together (into a books, catalogs, newspapers or magazines), presses that apply logos and decoration, addressing devices, collating and a variety of other devices are also used selectively to process individual sheet-like materials in bulk mailing and other processes. These various devices can be termed generally “utilization devices” as they utilize sheet-like materials that are typically dispensed in stacks. 
     Reference is made generally to U.S. Pat. No. 6,698,748, entitled SYSTEM AND METHOD FOR SINGULATING A STACK OF SHEET-LIKE MATERIALS, by H. W. Crowley, the teachings of which are expressly incorporated herein by reference.  FIG. 1  of the incorporated patent shows, by way of background, a high-volume envelope inserter in current use by industry and representing generally the state of the prior art. The depicted exemplary inserter ( 100 —in which the following numbers in parenthesis represent reference numbers in the incorporated patent) is a large, modular unit that combines various contents stored in hoppers (not shown) in the rear ( 102 ) of the device and that directs (arrows  104  and  106 ) contents ( 105 ) onto a raceway ( 108 ) downstream (arrow  110 ) toward a stack of envelopes ( 112 ). At each point along the raceway, additional insert sheets are added to the contents. These contents may be folded, or otherwise compacted, to fit within the selected envelope by mechanism within the inserter. Envelopes are drawn from the stack ( 112 ), and directed downstream (arrow  114 ) to an inserting station ( 116 ) at which the closed-but-unsealed envelope flaps ( 118 ) are opened so that the final contents ( 120 ) can be inserted thereinto. The filled envelopes ( 122 ) are then transferred further downstream (arrow  124 ) to a stacking position or further-processing module (not shown). 
     Industrial inserters, referred to generically as swing-arm inserters, are available from a variety of well-known companies including Bell &amp; Howell (Phillipsburg), as well as by Mailcrafter (Inserco model), Pitney Bowes (AMOS model), EMC Document Systems (Conquest Lsi model) and HM Surchin (Cornish model). A rotary variation is made by Buhrs (BB300 and BB 500) series. One more-specific example is the Bell &amp; Howell Imperial™. 
     Most inserters cycle at least 10,000 per hour without any material. However, once the various hopper materials are inserted into the envelopes, the net production is significantly slower. Due to paper handling problems, swing-arm inserters often net less than one third of their capabilities. A typical swing-arm device in production may net less than 3000 completed envelopes per hour. After careful study, it is now recognized that there are several issues of unreliability in the feeding of materials in conventional inserter devices. Many device areas are subject to jams. In fact, the design of these inserters has not changed significantly in 30 years. And for that matter, they have changed little since their invention 70 years ago, as exemplified by U.S. Pat. No. 2,325,455. 
     A number of inefficiencies and disadvantages have been noted in prior art swing arm inserters, for example, the overlying swing-arm structure of the inserter is complicated and difficult to access owing to a large number of interconnecting shafts that drive the various arm and gripper components. These shafts require a complicated series of adjustments and tuning to insure proper function. They also obscure access to, and view of, the contents feed hoppers, and more generally interfere with the operator&#39;s loading, unloading and operation of the device. In addition, the operative mechanism of the prior art inserter resides beneath a heavy feed table, which is only accessible from beneath. Repair and service of the mechanism is therefore inconvenient and requires the service person to stoop and crawl beneath the device for even the most basic tasks. Other aspects of prior art inserters are similarly deficient. For example, adjusting the size of an envelope in the envelope feed hopper requires adjustments to several elements on the downstream feed table. This is because the upstream end of the envelope hopper is fixed, while the downstream end must be moved, and this causes the synchronization of contents feed components with the envelope leading edge to change whenever the size is readjusted. Likewise, the inserter is constructed with a housing and table that are placed at an average height for an average worker with no easy way to change that height to accommodate shorter or taller operators. Also, while prior art inserters may contain a facility for dealing with the exhaustion or jamming of a “primary” contents hopper by providing a backup, or secondary contents hopper, such backup implementations are non-intuitive and difficult for an operator to implement. 
     Moreover, prior art inserters generally lack straightforward design in their individual components and power-transmission, making them more expensive to manufacture, more difficult to repair, and more prone to misfeed, due to bad tuning (given the many interconnected parts, which must interact perfectly). 
     Accordingly, it is highly desirable to provide an inventive high-speed envelope inserter, which intelligently addresses a variety of the foregoing concerns and thereby provides a more-serviceable, faster-running and generally more-reliable device. 
     SUMMARY OF THE INVENTION 
     This invention overcomes the disadvantages of the prior are by providing a system and method for inserting contents into envelopes that generally reduces the number of operative device components, locates all components in a readily and accessible location, reduces the number of adjustments needed to change envelope size and contents size, provides an efficient and aesthetically pleasing design, allows for a highly flexible arrangement of backup hoppers to primary hoppers for feeding envelope contents and otherwise affords a substantial number of improvements over currently available envelope inserters. 
     According to an illustrative embodiment, the device includes a “low-slung” swing arm design with a plurality of grippers for retrieving contents from hoppers and depositing contents on a moving raceway. The low-slung design employs a moving beam and a pair of opposing arms that are secured in a pivoting relation to a pair of respective uprights. This includes closely fitted shims so as to maintain a high degree of parallelism within the structure. This low-slung design insures that the area above the arm is relatively free of any inconvenient components that interfere, obstruct or hinder an operator&#39;s loading of the hoppers, or obscure his or her view of the hoppers&#39; contents. The contents hoppers include back and side supports that are easily adjustable and/or removable, and the entire working surface or table top, when removing the envelope hopper as well, can be pivoted into an inverted position with the swing arm extending into the volume of the underlying device housing. In this pivoted-open position, the moving/operative components of the device are fully exposed to the user at waist level for extremely easy inspection and servicing. 
     In an illustrative embodiment, device components are powered by a central drive motor that is attached to the underside of the feed table. Three shafts power all the components. One of the shafts is a continuously rotating shaft that powers elements requiring continuous motion. An interconnected shaft includes an indexer to provide intermittent motion to power, for example, the contents raceway belt. A third shaft arranged on an axis perpendicular to the first two shafts (fixed and intermittent) powers the swing arm and envelope inserter components. All shafts and their respective power take-offs are mounted on the underside of the table and readily accessible. 
     In an embodiment of the invention, the front face of the housing includes a concave panel that is aesthetically pleasing and also provides additional clearance for an operator&#39;s knees, etc. A further embodiment of this invention provides other desirable features such as moveable feet that allow the height of the housing to be raised and lowered to suit an operator. These feet can be electrically (or otherwise) powered in an embodiment of the invention. In addition, the device includes an elevated control panel with a highly intuitive control-switch-and-status-light display. The control switches include particular controls for activating/deactivating each of the contents hoppers and allowing adjustment contents hoppers to be designated as backups to a given primary hopper. In this manner, the device can be run continuously as each hopper is emptied in turn. The novel raceway belt having timing belt teeth driven by drive and follower sprockets, transports contents downstream to the insertion area and includes spaced-apart lugs that grasp trailing edges of contents and carry them forward, in the downstream direction. These lugs are attached through the belt with through-fasteners and respective backing plates that substitute for one of the timing belt teeth. The backing plates have a slightly smaller dimension than the timing belt teeth so as to avoid damage to drive sprockets. 
     In a further embodiment, the swing arm includes easily accessible internal fasteners that allow for quick removal and/or reconfiguration of individual contents grippers. Each of the contents grippers are driven by a common camshaft that operates to opening and close the grippers at opposing ends of the swing arm arc. Each opposing end of the swing arm arc, respectably, picks up contents from a hopper and deposits the contents onto the raceway. In a further embodiment, the insertion area of the device can include a not-moving table section that avoids many of the needed readjustments common to currently available envelope inserters. This non-moving table section allows for easy adjustment of the device to accommodate different-width envelopes. It relies upon a movable envelope leading edge (downstream) hopper guide plate and a clamp bar having a nip that can be adjusted in an upstream-to-downstream direction so that envelopes enter the constant-cycle envelope drive belt at an appropriate time to ensure proper registration with a downstream contents transfer and stuffing station. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention description below refers to the accompanying drawings, of which: 
         FIG. 1  is a perspective view showing a general overview of a high-speed envelope inserter according to an illustrative embodiment of this invention; 
         FIG. 2  is a more-detailed partial perspective view of the envelope feed table surface for the inserter of  FIG. 1  featuring a “low-slung” swing arm design in accordance with an illustrative embodiment; 
         FIG. 3  is a side cross-section of the swing arm beam and removable gripper assembly according to an illustrative embodiment; 
         FIG. 4  is a side cross-section of the swing arm beam and removable gripper assembly showing the gripper assembly removed; 
         FIG. 5  is a partially exposed side perspective view of the inserter feed table being rotated so as to access the operative mechanism along the underside thereof; 
         FIG. 6  is a partially exposed side perspective view of the inserter feed table of  FIG. 5  shown secured in an upright orientation, ready for operation. 
         FIG. 7  is a fragmentary perspective view of the contents raceway conveyor belt and associated drive sprocket including an inventive pushing lug assembly according to an illustrative embodiment; 
         FIG. 8  is a plan view of an illustrative control panel arrangement for the inserter of  FIG. 1 ; 
         FIG. 9  is a flow diagram of procedure for switching from primary to secondary, backup contents feed hoppers according to an illustrative embodiment; 
         FIG. 10  is a diagram of an exemplary backup hopper setup in accordance with the control panel arrangement of  FIG. 8  and the procedure of  FIG. 9 ; 
         FIG. 11  is a schematic plan view of the general arrangement of continuously driven and intermittently driven power transmission shafts for operating various components of the system according to an illustrative embodiment; 
         FIG. 12  is a schematic side view of a an eccentric-cam-driven pivot bar applicable to the shaft arrangement of  FIG. 11 ; 
         FIG. 13  is a schematic side view of an eccentric-cam-driven slide bar applicable to the shaft arrangement of  FIG. 11 ; and 
         FIG. 14  is a top view of the envelope insertion area of the inserter of  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION 
     A system for inserting contents into envelopes  100  is shown in  FIG. 1 . In overview, the system  100  (also termed herein generally as the “inserter” or “device”) includes a main housing  102  having a concave front panel  104  that particularly aids workers in gaining closer access to the device (with room for knees), and also provides a unique, pleasing appearance to the device housing  102 . 
     The housing  102  is supported on at least four heavy duty caster wheels  106  that provide portability. In general the housing  102  is a relatively lightweight structure consisting of an internal framework (not shown) and removable covering panels that allow access to the device&#39;s interior (as an alternative to the flipping-table system described below). The caster wheels  106  are supplemented by at least four (located adjacent each of the four caster wheels) retractable feet  110  that resist sliding, once deployed. The feet move up and down (double arrows  112 ) based upon a manual or automated drive system (a screw drive for example). This drive system allows the elevation of the housing  102  to be raised and lowered to accommodate different-height users. An up/down switch  113  can be located at a convenient position on the housing  102  to facilitate upward and downward movement. The top side of the housing  102  includes the working surface or table  124 . This table surface  124  is constructed from a casting of aluminum in this embodiment, although it can be constructed from sheet and/or plate components in alternate embodiments. 
     The illustrative table surface  124  contains all of the exposed components needed to insert predetermined contents into envelopes. The envelopes  128  are stored in a stacking hopper  126 . In alternate embodiments, a cartridge that includes envelopes can be provided. Such a feeding system is shown and described in U.S. Pat. No. 6,663,100 entitled “SYSTEM AND METHOD FOR SUPPLYING STACKED MATERIAL TO A UTILIZATION DEVICE,” by H. W. Crowley, the teachings of which are expressly incorporated herein by reference. Contents, which comprise folded, or otherwise appropriately dimensioned, documents that are sized to be inserted into envelopes  128  within the hopper  126 , are stored in a series of contents hoppers defined by removable and adjustable back guides  130 ,  132 ,  134  and  136 . Each depicted back guide represents a feed station for selected contents. Pairs of removable side guides  138  define the upstream and downstream widthwise edges of each content feed hopper. An exemplary set of contents  140  are shown stacked with respect to the first back guide  130 . In this embodiment, two additional content feed stations/hoppers can be provided in the open area  142  residing downstream of the back guides  130 - 136 . The side guides  138  are each removably attached to the underlying bar by pinch clamps and turn screws (not shown) of relatively conventional design. They can be slid (double arrows  157 ) along the bar and secured in place to define the appropriate upstream-to-downstream width for a respective stack of contents. 
     As used herein, the terms “upstream” and “downstream” refer to the flow of both contents and envelopes through the device. The upstream end  150  is at the beginning of a contents raceway that is defined by a moving, continuous transport belt  280 . The belt  280  moves downstream in the direction of arrow  154  until all contents on the raceway are presented to an insertion area  156 . Envelopes  128  are driven in succession into the insertion area  156  from the envelope hopper  126  along a continuous feeding belt  158 . A series of pickers  160  and pusher fingers that are part of a contents-insertion transfer station  162  (described further below) urge the envelope into a flap-open position while retrieving, in turn, the now-stacked contents from the raceway, and driving these contents pieces through the flap opening on the envelope. A wetting system, which is fed by a reservoir  170  in an elevated control panel  172 , is used to wet the adhesive on the envelope flaps so that they may be sealed. In this embodiment, the now-sealed envelopes are passed from the station  162  through a twisting belt arrangement  174  to a final, downstream location where they are boxed, stacked, or otherwise accumulated. 
     According to a novel feature of the device  100 , contents are drawn from respective stacks using cam-actuated grippers  180 . The grippers  180  are mounted at the end of a swinging bar or beam  182  that swings, pendulum-like, through a predetermined arc between one end position adjacent to the raceway and an opposing end position adjacent to the contents stacks. The bar or beam  182  swings on the end of each of two durable (aluminum in this example) arms  184  at each or the opposing ends of the beam  182 . The arms  184  each include clevis assemblies  186  with pivot pins  188  that pass through each of a pair of overhanging uprights  190  and  192  that are fixed to the table  124 . 
     The swinging arm and beam components will now be described in further detail with reference to  FIG. 2 . Various components associated with the device&#39;s top surface  124  have been omitted for clarity. For example, only the upstream-most and downstream-most grippers  180  are shown. As will be described below, grippers  180  can be removed easily from the beam  182  as needed for service or reconfiguration of the device. The beam  182  is constructed from aluminum, steel or another durable material in the form of a channel member  210  with an overlying, removable access cap  212 . The specific arrangement of parts to define the beam is widely variable. The cap  212  is attached by a series of bolts or other removable fasteners  214  in this embodiment. Again, a variety of attachment mechanisms can be employed. As described above, each of the opposing ends of the beam  182  are attached to a respective swing arm  184 . In this embodiment, the swing arm  184  is constructed from bar stock or another solid material with a lower portion attached to the beam and an upper clevis portion  186  that is split into side-by-side wings  220  with a central slot  222 . The central slot  222  is sized and arranged to closely conform to the width WA of each upright  190  and  192 . The respective pivots  188  are also relatively closely conformed to both the upright and the clevis  186 . This arrangement results in each swing arm  184  being maintained at conforming right angles to the uprights  190  and  192  so that minimal twist, or other unwanted non-parallel movement, occurs as the arm swings (double curved arrow  230 ) about the axis of each pivot  188 . 
     In general, the tolerance of each swing arm slot  222  with respect to the width WA of the upright is in a general range of two to five thousands of an inch in order to obtain desired parallelism throughout the arc of swing. In an illustrative embodiment, such close tolerances can be obtained by inserting shims of a given thickness along the pivot between the upright and the clevis. In this manner, the actual slot width can be significantly wider than the width WA of the upright to a count for variability in these dimensions. An appropriate-thickness shim  240 ,  242  (shaped as an annular washer in this example) is then inserted on each side of each upright between the clevis wing and the upright. 
     The downstream swing arm ( 184 ) is interconnected at the pivot point  188  to a drive arm  250  that is fixed by fasteners  252  to the clevis wing  220 . This drive arm  250  is a rigid beam with an opposing end  254  that rides on a pivot  255 , which is, in turn, attached to a drive wheel  256 . The drive wheel  256  is mounted on a keyed (or otherwise rotationally filed—e.g. splined) shaft  258  that communicates with a drive motor system so that the rotation (curved arrow  260 ) of the drive wheel  256  is translated into a rocking motion within the arm  250  about the pivot  188 . The degree of eccentricity on the wheel  256  between the shaft  258  and drive arm&#39;s pivot  255  dictates the resulting arc (double-curved arrow  230 ) through which the beam  182  swings. This arc can be adjustable, but is typically a fixed degree value. The degree of the arc should be sufficient to allow the grippers  180  to transition between a location on the raceway and a location in which they engage the bottom sheet in each contents stack. 
     It should be clear that the use of uprights and a swinging beam with high parallelism allows the upper region of the device to be essentially free of interfering components, secondary drive shafts and other items that complicate the device and can interfere with the operator&#39;s ability to properly load, unload and operate the device. In addition, the open and “low-slung” arrangement of the swinging beam and uprights facilitates its easy viewing and convenient loading access to each of the contents bins. This aids workers in monitoring when contents are about to become exhausted from a given bin. As discussed above, envelope inserters according to prior art arrangements include a plurality of such overhanging rods, interconnections, and the like. The novel arrangement of this invention effectively eliminates such features. 
     As further shown in  FIG. 2 , the contents feed hopper back guide  130  (etc.) can be quickly removed from the rear support table  270  by turning a pair of handles  272  that selectively engage and disengage respective key slots  274  with corresponding locking cams (not shown) that can comprise a conventional implementation. The slots  274  are oriented with elongation perpendicular to the upstream-downstream direction. This allows the width of contents within a given hopper to be varied by sliding (double arrow  159  in  FIG. 1 ) the back guide (exemplary guide  130  in this example) along the slots  274  to the appropriate location, and then locking the handles  272 . The sliding, adjustable back guides act in concert with the adjustable-width side guides  138  described briefly above. The side guides  138  are mounted to a rail  196  (see also  FIG. 12  further detail) for that is positioned behind the swinging beam  182 , and between the two uprights  190  and  192 . The rail is omitted from the view in  FIG. 2  for clarity, but is shown in  FIG. 1 . The rail  196  also supports movable vacuum suckers that selectively engage the bottom sheet in each stack of contents, and allow its leading edge to be spaced downwardly from the upper sheets in the stack so as to enable a respective gripper  180  to engage the contents sheet when the beam attains the rearmost end of the arc. The structure and operation of a novel sucker assembly is described in the above-incorporated U.S. Pat. No. 6,698,748, entitled SYSTEM AND METHOD FOR SINGULATING A STACK OF SHEET-LIKE MATERIALS, by H. W. Crowley. 
     The contents pieces ( 140 ) are moved downstream along the raceway  150  on a belt  280 . Briefly, the belt  280  includes spaced-apart lugs  282  that project upwardly from the otherwise relatively smooth surface of the belt. The belt resides within a trough or slot  284  formed within the table top  124 . The underside of the belt  280  (described further below) includes a set of spaced-apart teeth, in the manner of a timing belt. These teeth engage corresponding sprocket teeth on a drive and follower roller on each of opposing upstream and downstream ends of the belt&#39;s run on the raceway  150 . Certain teeth are removed or shortened to accommodate a backing plate that secures a given lug  282  to the belt  280  using fasteners, adhesives and/or other attachment systems. The lugs  282  can be constructed from a durable medal, plastic or another material. 
     Significant economy of moving components is achieved by the gripper assemblies  180  of this embodiment. With further reference to  FIG. 3 , each gripper  180  is secured to the bottom side  310  of the beam  182  by (in this example) threaded fasteners  312 . A variety of attachment mechanisms are contemplated in alternate embodiments. The gripper  180  consists of a lower jaw  320  that is fixed by an upper base  322  to the beam  182 . The movable upper jaw  330  is attached by a pivot  332  to the base  322 . The lower and upper jaws  320 ,  330  together define a movable pincer  336  that pivots between a gripping position and an open position. The pincer jaw is normally biased closed by a compression spring  340  so that varying thicknesses of contents can be accommodated with a relatively constant gripping pressure provided by the spring. During the midcourse of the arc, as shown in  FIG. 3 , the pincers are normally in a sprung-closed position (herein instead shown opened against the spring bias for clarity). A common cam bar  350  interconnects the tail end of each upper jaw  330  of each gripper  180  along the beam. A cam trip assembly  352  at the downstream end  298  (shown in  FIG. 2 ) comes into engagement with a pair of ramps  360  and  362  located with respect to each of opposing ends of the beam&#39;s swing arc. Thus, when the cam trip  352  and interconnected cam bar  350  move adjacent to the raceway belt  280 , the cam trip  352  and bar  350  thereby come into engagement with the ramp  360  and cause the gripper jaws  320 ,  330  to open, which deposits any gripped contents onto the raceway belt  280 . Similarly, when the beam  182  swings toward the contents hoppers, the ramp  362  engages the trip  352  and interconnected cam bar  350 , thereby causing the gripper jaws  320 ,  330  to open so as to enable gripping of the plucked bottom contents of the contents hopper stack ( 140  in  FIG. 1 ). In an illustrative embodiment, the ramp  362  can include a latching mechanism that causes a sudden snap-closure of the jaws to occur as the beam withdraws from its rear most position, thereby ensuring that the contents are firmly gripped before the grippers pass out of an overlapping orientation with the contents. Such a latching mechanism can be implemented in accordance with conventional mechanical design techniques, and is not further described. 
     As shown in  FIG. 4 , one or more gripper assemblies  180  can be readily removed for servicing, replacement or reconfiguration of the device (i.e. changing the number and positioning of contents hoppers) by removing the top cap  212  of the beam  182 , or otherwise (for example through access holes) gaining access to the interior of the channel portion of the beam so that the gripper base fasteners  312  can be backed out, or otherwise disengaged. As such, the base  322  of the gripper assembly  180  is detached from the bottom side  310  of the beam  182 . In one embodiment, the cam bar  350  is a continuous rod that is connected through all of the grippers. The upper jaw  336  can be adapted to allow detachment from the bar  350 . Conversely, the bar can be segmented, with the bar segments between each of the grippers being attached using a conventional coupling—for example, an Oldham coupling. Alternately, grippers may simply be slid off by moving them down the (one-piece) bar  350  and off of (for example) the upstream end once the grippers are all detached from the beam  182 . Other forms of attachment mechanism that allow for entirely external attachment and detachment of gripper assemblies  180  can also be employed in alternate embodiments. 
     The above-described low-slung design, in combination with other efficient implementations of device components allows for highly useful and novel arrangement for accessing the various moving mechanisms of the device. As shown in  FIG. 5 , the table top  124  can be rotated (double curved arrow  527 ) almost 180 degrees (135-145 degrees as shown) to expose most of the essential operative components of the device. As further shown, the table top  124 , and the interconnected rear contents-hopper-supporting surface  270  is rotated (curved arrow  526 ) about a pair of opposing pivots  510  and  520  into the depicted exposed position. In this position, the rear contents hopper support surface  270  moves from its original position overlying the rear frame rail  520  to an upside down orientation, suspended over the front face  104  of the housing  102 . Note that before rotating the table assembly, the user need only remove the envelope feed hopper  128  and each of the contents back guides  130 ,  132 ,  134 ,  136 , and corresponding back guides  138 , so that these components do not interfere with the rotational motion. The front side (edge  530 ) of the main tabletop  124  is submerged within the open volume of the housing  102  as shown. The table  124  and rear surface  270  are balanced with respect to the pivots  510  and  520  so that very little force is required to rotate the assembly. In general, the top&#39;s weighting favors the depicted open position so that releasing the hold-downs  556  (described below) causes the table to gently rotate open. The pivoted opening of the table top  124  is limited the where the front edge  530  of the table top  124  engages a small bumper (not shown) on an upright frame member(s)  538  within the interior of the housing  102 . A variety of rotation-limiting, or stopper, mechanisms can be employed in alternate embodiments to restrict the degree of rotation of the table top  124  into the inverted orientation whereby components are exposed. 
     As further illustrated in  FIGS. 5 and 6 , all, or a vast majority, of the operative mechanism of the device is mounted to the bottom side of the table  124  and adjoining surface  270 . That is, drive motors, drive rods, raceway components, pneumatic circuits and electrical circuits can be largely provided within the underside of the table and made easily accessible. In one embodiment, the table is constructed as a solid casting with appropriate cutouts and strengthening ribs. The surface  270  can be a sheet metal plate mounted on ribs that extend from the table  124 . It should be clear that a variety of table and surface structures can be employed in alternate embodiments. While not shown, certain components such as pumps, lifting mechanisms and power distribution components can be provided within the roomy volume of the housing, generally off to one side—such as at the downstream rear corner beneath the control panel  172 . 
     Securing the table top  124  and rear contents hopper supporting surface  270  to the underlying housing is relatively simple. A pair of elastomeric, T-shaped hold-downs  550 , which can be a conventional design, are attached to each of opposing end ribs  552  and  554  on the table. These ribs  552  and  554  can also be employed to secure part of the surface  270  to the table  124 . The hold downs each include a hole or other locking structure adjacent to the T-shaped end  556 . As shown in  FIG. 6 , when the table assembly is forcibly pivoted into a closed orientation by the operator, each of the T-shaped hold downs is tensioned so that the hole passes over a fixed post or other locking base (not shown) secured to the rear side of the housing  102 . Typically, each post is secured on a plate (not-shown) attached to an upright frame member within the housing. A pair of feet or cushions  522  (see also  FIG. 5 ) are provided on the bottom side of the overlying supporting surface  270  to prevent damage. It should be noted that a variety of securing mechanisms can be used in alternate embodiments. In addition, while the rotation of the table assembly is performed manually in this embodiment, hydraulic, numeric and/or electromechanical systems can be employed to rotate the table assembly and/or to lock it in place. In a further alternate embodiment, gas springs or other damping mechanisms can be used to slow the opening of the device. Such damping mechanisms can be rotary dampers that act in conjunction with the pivot or linear dampers that are attached to appropriate portions of the table assembly and to the housing. 
     It should also be clear that the above-described arrangement for allowing easy access to most, or all, moving device components provides a substantial improvement over prior art devices. Such prior art devices typically require removing of one or more panels on the housing to access permanently fixed components therein. A large number of interconnecting gears, pushrods, links and other members are provided between the elements in the housing and the exposed elements on the table assembly in such prior art arrangements. Hence, these prior art arrangement make the servicing of the device more uncomfortable for the maintenance worker, as significant time must be spent stooping down, and working in uncomfortable orientations beneath the device. 
     As described above, the raceway&#39;s contents transport belt  280  includes a plurality of regularly spaced lugs  282  that are located at spacing distances that are sufficient to span the width of the maximum-width (upstream-to-downstream width) contents expected to be presented to the system  100 . As shown further in  FIG. 7 , in this embodiment, the belt  280  is constructed with a series of regularly-spaced timing-belt grooves  710  that are adapted to engage corresponding teeth  720  on a drive sprocket  730 , and an opposing, similarly shaped follower sprocket (not shown). The drive and follower sprockets maintain the registration of the lugs  282  as they move along the raceway with the drive sprocket  730  being part of the overall central drive motor system (not shown). The lugs  282  are provided to the continuous belt  280  using a novel technique. Each tooth  710  on the belt has an average height HL as adapted to conform to the teeth  720 . Since the belt is elastomeric, its teeth will not generally mar the teeth of the sprocket, thereby assuring the sprocket a long life. However, the lugs present a concern in that securing them to the top of the belt requires a stiffener plate  760  on the opposing side of this embodiment. The stiffener plate  760  is adapted to reduce the risk of marring of the sprocket teeth  720  because the plate  760  defines a width WP that is narrower by several thousandths of an inch than the maximum WT of a standard belt tooth. Likewise, the height HP of the plate  760  is less by several thousandths (or more) of an inch than the maximum height HL of a conventional tooth. It has been determined through observation that, for a sprocket having a diameter of at least two to three inches, the adjacent teeth  710  to the plate  760  maintain sufficient contact with the sprocket teeth so that the plate never digs into a sprocket tooth  720 . In this manner, the lug is effectively secured (by through-fasteners, such as rivets  750 ) to the top of the belt  280   
     In this embodiment, the lug  282  also includes a pair of opposing, upright, outer wings  740  having a height of approximately three-sixteenths to five-sixteenths of an inch in this embodiment. The center region of the lug  282  between the wings  740  consists of a shorter-height plate  752 , through which the fasteners  750  pass. Various different lug geometries are expressly contemplated according to other implementations, each with the goal of urging contents deposited by grippers downstream to the collection and insertion area of the device. Likewise, the technique for attaching a lug to a belt is widely variable and the depicted technique is one of a variety of possible attachment techniques. 
       FIG. 8  shows an exemplary control panel face  810  that resides on the front of the suspended control console  172  ( FIG. 1 ), according to an illustrative embodiment. The control panel  810  includes a conventional power switch for activating the device. Emergency stop switches, circuit breakers and other operation-interlock/safety mechanisms (for example, the kill device-operation button  199  on the table  124  in  FIG. 1 ) can be placed at convenient locations on the device housing  102 . In addition, there is a caliper switch  822  that allows for the setting of the grippers&#39; set-point to match a given standard-thickness sample of the contents to-be-inserted. The panel also includes an envelope counter readout  824 . A variety of fault and jam detectors, which operate based upon inputs from grippers and other system components, are provided in the window  830  of the panel  810 . These and other components of the device&#39;s control system can be run using a microcontroller, microprocessor, and/or state device logic as appropriate. In an illustrative embodiment, a microprocessor of appropriate size and processing speed is employed along with an associated memory (neither being shown). 
     Notably, the control panel  810  includes an array of six hopper “on-off” switches  850 ,  852 ,  854 ,  856 ,  858  and  860  (denoted as Hoppers  1 - 6 , respectively, in an downstream-most to upstream-most arrangement). When a given on-off switch is shifted from the “off” to “on” position, the vacuum valve for a given contents-hopper sucker is activated. This operational vacuum enables the bottommost piece to be drawn downwardly so that it is aligned to engage the swinging gripper for the selected contents hopper. When the vacuum is switched off, the gripper misses the bottommost piece at the end of its swing-arc, and the bottom contents piece is not drawn. Note that when a hopper is switch on, the gripper looks for an appropriate thickness (caliper) of contents to be provided thereto. An electro-optical or resistance-based sensor within each gripper assembly determines when the gripper jaw has deflected due to the presence of a contents piece. When an appropriate degree of deflection has occurred, then the system is signaled that a contents piece is present. A variety of conventional electromechanical and/or electro-optical detectors can be employed in this arrangement. If contents pieces are not gripped, or more than one contents pieces are gripped by the grippers, then a fault light  870 ,  872 ,  874 ,  876 ,  878  and  880  is indicated for the respective hopper (Hoppers  1 - 6 , respectively). 
     Referring now to the flow diagram of  FIG. 9 , the system “ASAP” procedure  900  checks the status of each hopper. If a hopper is switched on (decision step  910 ), then the system procedure  900  determines whether the hopper&#39;s gripper caliper (e.g. degree of opening) indicates a fault or miss (decision step  920 ). If hopper is not toggled on, or no miss is determined, then the system procedure moves to the next hopper (step  930 ). If, however, a miss/fault in gripping a contents piece is indicated for an activated hopper, then the system procedure branches to decision step  940 . With reference also to  FIG. 8 , the control  810  includes five backup switches  890 ,  892 ,  894 ,  896  and  898  that overlie the associated indicia for each hopper (e.g.  1 - 6 ). The back up switches can be toggled between off and on. When a backup switch is toggled on, it allows the system to automatically switch from a given right-hand hopper to the immediately adjacent left-hand hopper when the right-hand hopper experiences a fault (as indicated by one of the lights  870 - 880 ). Hence, in the decision step  940 , a misfeed (branch  922  from decision step  920 ) causes the system to look for a backup switch to the left of that hopper in an on position. If there is no designated backup for that hopper, then the system triggers a stop of the device (step  950 ). However, if a backup switch to the left of the faulty hopper is toggled on, then the faulty or “primary” hopper is turned off (caliper is no longer scanned, and the vacuum of the sucker is deactivated), and a secondary hopper to the left of that hopper is turned on as shown in step  970 . The system then returns via branch  972  to scan the next hopper in step  930 . The process continues indefinitely until the job is complete or the device is cycled off. Hence, the backup switches allow automatic switching from a first or primary hopper to a secondary hopper without experiencing a device stoppage. Typically, the right-most hopper (e.g. Hopper  1 ) on the panel  810  represents the most-downstream hopper. In the example of  FIG. 1 , the two downstream most hoppers have been disabled and no backing guides are provided thereto. Thus, switches  1  and  2  would be in the off position in that implementation. 
     By way of a basic operating example, as shown in  FIG. 10 , all Hoppers  1 - 6  ( 850 - 860 ) are switched into the on position—meaning that they are all being used as either a primary contents source or a secondary, backup, contents source. The backup switch  890  between Hopper  1  and Hopper  2  is switched on, meaning that Hopper  2  is a backup to primary Hopper  1 . Likewise, the backup switch  892  between Hopper  2  and Hopper  3  are switched on. This means that when Hopper  2  becomes a primary (due to a fault or emptying of Hopper  1 ), then Hopper  3  becomes a backup to it. However, the backup switch  894  is toggled off. This means that Hopper  3  has no backup, and its fault would cause the system to stop. Since Hopper  4  is activated, it is its own primary source but, the backup switch  896  allows Hopper  5  to become its backup. Since the final backup switch  898  is toggled off Hopper  6  has no backup and operates only as a primary. Again, its fault would cause the system to stop. It should be clear that a large number of variations on the exemplary settings in  FIG. 10  can be implemented in accordance with alternate embodiments. For example, where all backup switches  890 - 898  are toggled on, and all hopper switches  870 - 880  are toggled on, each hopper will be emptied, and in turn, before the device shuts off. Where all hoppers are filled with the same identical contents pieces, this arrangement allows for an extremely long runtime before hoppers must be refilled with new contents pieces (if at all). Likewise, where some contents pieces are significantly thicker than others, they can be spread among two adjacent hoppers to provide the same number of contents pieces as an adjacent hopper having larger number of thinner contents pieces in its stack. For example, two adjacent hoppers accommodate one hundred thick pieces, fifty each, while the next hopper accommodated one hundred thinner pieces in a single stack. 
     Typically envelope inserters include functional components (such as the swing arm that require a continuous drive, while other components, such the contents insertion assembly, require an intermittent drive that operates only at particular times relative to the continuous drive—for example, when the contents are all accumulated before an envelope, and ready for insertion. Most prior art inserters employ several different power transmission shafts and bearing points to implement such an arrangement. This increases the machine&#39;s cost and complexity and leads to higher maintenance costs and failure rates. 
     Conversely, the device  100  in the illustrative embodiment includes a novel arrangement of operative components (all of which are mounted on the underside of the table  124 , as described above) that effectively reduces the number of shafts to a total of three.  FIG. 11  details schematically the arrangement  1100  of power transmission shafts as viewed from below the table  124 . The bottom of the figure represents the area nearest the front face of the device, while the top represents the area nearest the rear face of the device. The sides of the figure are oriented in the upstream-to-downstream direction. The device is powered by a central drive motor  1110 . The motor  1110  is mounted to the underside of the table using conventional motor mounts that can include conventional vibration-damping components. The motor  1110  can be any acceptable type, typically with a variable speed capability and operated by AC electric power (typically 110 VAC, 220 VAC and/or 440 VAC, single-phase or three-phase). The motor  1110  is connected by a sprocket  1112  and drive chain or belt  1114  to a driven sprocket  1116  mounted on the first, continuous motion shaft  1120  (continuous rotary motion being represented by a solid curved arrow  1122 ). The shaft  1120  is supported by at least two bearings  1124  and  1126  at opposing ends thereof. The bearings can be presses or otherwise secured into mountings that are attached to or integral with the underlying table  124 . The continuous shaft  1120  drives device components which require a continuous rotary output using each of a plurality of take-offs  1128 . Some takeoffs ( 1128 ) are chain or gear drives for transferring direct rotary motion, while others operate pivoting bars or slides where a reciprocating, linear or arcuate motion is needed. 
     Referring briefly to  FIG. 12  a pivoting bar takeoff  1200  that can be driven by the shaft arrangement  1100  is shown. The takeoff  1200  includes a bearing fulcrum  1210  that is secured to the table  124  or other part of the device  100 . The fulcrum  1210  allows a drive bar  1220  to reciprocally pivot thereby producing a generally linear reciprocating motion (double arrow  1222 ) at an end actuator  1224 . The bar is driven by a cam  1230  with a circular or non-circular (e.g. lobular) perimeter mounted eccentrically with respect to the shaft  1250  (representative of any shaft in the arrangement  1100 ). The shaft rotates in either direction (arbitrarily shown as curved arrow  1260 ) to cause a cam follower  1270  to rise and fall against the undulating surface  1280  of the cam  1230 . The cam follower  1270  can be either a solid, non-moving, low-friction component, or a rotating wheel like that shown in  FIG. 12 . A tension (or compression) spring can be fixed to the device at a base  1272 , and bias the arm  1220  against the cam  1230  so as to ensure an accurate path of travel for the follower  1270  relative to the moving cam  1230 . 
       FIG. 13  details an alternate implementation of a linear drive takeoff  1300 . In this embodiment, the exemplary shaft  1310  rotates (curved arrow  1320 ) an eccentric cam  1330  that contacts an overriding fixed or rotating follower  1340  that bears against the cam surface  1350 , either by weight or spring bias. The follower  1340  is directly connected to a linear actuator arm or shaft  1360  that transmits reciprocating motion (double arrow  1370 ) to a desired device component. Note that a chase or channel  1380  is provided through the table ( 124 ) or other device surface  1382  to allow the actuator  1360  to pass therethrough. 
     Referring again to  FIG. 11 , as discussed above, the continuous shaft  1120  typically contains takeoffs  1128  that drive such system components as the raceway hold-down lift, envelope-flap-opening suckers, open-flap clamping mechanism, envelope hopper elevator and envelope hopper pusher. The continuous shaft includes a drive sprocket  1140  and drive chain  1150  that connect to a driven sprocket  1152  on a parallel second shaft  1160 . The driven section  1162  of the shaft  1160  is mounted on bearings  1164  that are also fixed to the underside of the table  124 . This shaft section  1162  is driven at a faster, 2:1 ratio with respect to the first continuous shaft  1120  by providing differently-sized sprockets  1140 ,  1152 . This shaft includes a bevel gear  1166  at the front end to drive a perpendicularly (90-degree) offset bevel gear  1165  on a perpendicular (aligned upstream-to-downstream) third shaft  1170  also mounted on fixed bearings  1172 . This shaft includes the takeoff  256  ( FIG. 2 ) that drives the swing arm assembly (arm  250 ), and a takeoff  1174  that drives contents pusher fingers in the envelope insertion section. Since both of these components require reciprocating motion that is perpendicular to the upstream-to-downstream feed direction, the shaft  1170  is, thus, aligned with a rotational axis in the feed direction. This shaft  1170  rotates (curved arrow  1176 ), using gear reduction, at a speed of ½ the speed of the second continuous shaft  1120 , thereby providing the requisite duty cycle of its interconnected components. 
     The opposing end of the shaft section  1162  of the overall (second) shaft assembly  1160  is connected to the driven member of an indexer assembly  1180 . A variety of indexer designs known in the art can be employed to implement the indexer assembly  1180 . In this embodiment, the indexer includes a cam  1182  and follower  1184  on the end of a crank-arm that is connected to the intermittent shaft section  1186 . Likewise, this shaft section  1186  is secured by fixed bearings  1188  to the underside of the table  124 . As should be capable of implementation by one of ordinary skill, the driven cam  1182  of this embodiment includes spring loaded-gate that directs the follower into an eccentric slot that captures the follower and cranks it through one revolution. Since the second shaft assembly  1162  moves at twice the speed as the first shaft assembly  1120 , the indexed section of the second shaft assembly&#39;s one revolution equals half a revolution for the first shaft (and its components&#39; duty cycle). The gate releases the follower  1184  from the indexer&#39;s eccentric slot on the second revolution of the second shaft&#39;s driven section  1160  and the follower/crank assembly idles during this second revolution. Thus the second shaft&#39;s indexed section  1162  rotates one revolution during half the rotation cycle of first shaft, while pausing during the other half of the first shaft&#39;s cycle. This provides the requisite intermittent rotary motion (designated by dashed arrow  1190 ) needed to drive and pause the lugged raceway belt ( 280  in  FIG. 2 ) in each cycle. This intermittent operation is desired because the raceway belt should briefly pause for contents to be deposited on the raceway by still-moving grippers, and also pause for contents to be inserted downstream into waiting, flap-opened envelopes by contents pushers. A drive sprocket takeoff  1192  is provided to the intermittent shaft section  1186  so as to drive the raceway belt as described above. 
     Reference is now made to  FIG. 14 , which shows a top view of the insertion area  156  of the device. The insertion area receives contents from the raceway  280  where they are deposited in a contents insertion transfer station  162  that includes a set of side-by-side contents pusher fingers  1410 . The pusher fingers are constructed from a durable material, such as a hard plastic. They slide along an underlying feed surface  1412  that can be constructed from a ferromagnetic material. While not shown, each of the contents pusher fingers  1410  includes a strong magnet (not shown) in its base that allows it to remain securely, but slidably engaged to the plate  1412 . The pusher fingers  1410  are pivotally mounted on extension arms  1414  that project rearwardly to a pivot shaft  1415 . The pivot shaft is secured to a drive arm  1418 . The drive arm is secured by a base to the swing arm  184 . In this manner, each time the lug belt  280  delivers a new contents to the plate  1412  of the transfer station  162 , the swing arm  182  urges the pusher fingers  1410  forwardly to drive (arrow  1422 ) the contents transverse to the downstream direction and towards a waiting opened envelope that has been transferred from the hopper  126  along an envelope conveyor belt  1425  to an envelope stuffing station  1428 . The contents pieces arrive at the transfer station  162 , and are driven under a set of parallel brushes  1425  that hold the contents flat for the pusher fingers  1410  to thereafter drive each delivered contents piece into the waiting envelope. The pusher finger pivot shaft  1415  rides on a ramp (not shown) that allows the fingers to rise above the incoming contents insert when withdrawn to a rearmost position after feeding. Unlike prior art, this ramp is not adjustable, and is rigid so it cannot be bent out of shape and does not contact the transfer station. As such the ramp causes none of the potentially annoying clinking sound experienced with prior art ramps. The ramp has a discontinuity at its rearmost location that causes the bar to drop back down, returning the fingers  1410  into contact with the underlying plate  1412 . The transfer station plate  1412  can include a rubber landing zone to further eliminate noise, grooves  1431  that interlock with the fingers to prevent insert material from inadvertently passing underneath as they  1410  reciprocate therealong. 
     Note that the raceway includes overlying raceway contents hold down “skis”  1417  that are each mounted on a common rotating shaft  1415 . The hold downs  1417  normally overlie the contents as they pass downstream on the raceway. The hold downs  1417  retract as the grippers  180  deliver contents onto the race way so as to provide clearance for the grippers  180  to deposit their respective contents thereon. The hold downs then reengage as the contents move along the race, again retracting, and opening for the next gripper-delivery cycle. In the illustrative embodiment, the hold downs can be metal plates that do not actually engage the contents with pressure, but rather reside approximately one quarter to one half inch above the belt. This geometry boxes in the material so it remains on the moving belt. Also, the upstream edge of each hold down can include an upwardly ramped end to help guide the contents thereunder. In general, the hold downs serve to prevent contents from becoming unfolded or otherwise falling off the race way. In this manner, the contents remain under physical control and engagement of a paper-handling device during substantially all stages of the process (with the grippers handing that control/engagement responsibility off to the hold downs during the raceway-delivery stage of the process). 
     Note further that the envelope hopper  126  includes a series of uprights  1430  that are secured to the table  124  by slotted brackets  1432  and thumb screws  1434 . Thus, the spread of uprights in the envelope hopper  126  can be adjusted for envelope width (double arrow  1436 ) by sliding the brackets  1432  appropriately and locking the screws  1434 . Beneath the hopper resides a moving envelope elevator  1438  that is powered by the continuous power transmission shaft described above. The elevator includes a series of suction cups  1440  to which a vacuum is applied under control of the controller to intermittently grasp and release envelopes drawn from the bottom of the hopper. Unlike prior art, each and every of these cups is independently connected to a respective vacuum chamber. Therefore, if one sucker does not make contact and looses vacuum, the other suckers will still perform. Hence, the suckers can each be said to obtain suction from an “independent vacuum source.” Envelopes, which are drawn by the elevator  1438 , are then engaged and driven onto the belt  1426  by a rod-mounted pusher block  1441  which drives the upstream edge of each drawn-down (by the elevator) envelope out of the bottom of the hopper stack, and onto the envelope drive belt and flap plow assembly  1444 . 
     Envelopes are thereby vacuum-released onto the envelope conveyor belt  1426  where they are pushed into a waiting nip arrangement. The envelopes are grasped by a nip defined between the belt and a clamp bar ( 1478 , described further below) that applies a predetermined pressure to the belt. When driven from the hopper, the envelope flaps are in a closed position. They pass through a flap-opening section  1444  that includes an overriding flap plow  1446  that engages a closed flap, and biases it open. The flap then engages a knife, whose leading edge is above the top surface of the incoming envelope behind the flap section, but transitions to below the flap before it contacts the flap. This geometry ensures the knife will scrape the flap open, even if the subsequent upstream flap plow does not open. As such the opened flap is rotated by the plow at its seam 180 degrees, laying the flap flat against the working surface of the feed table. When the belt completes its cycle, the opened envelope stops with its opened side in registration with the stuffing station  1428 —where a series of grippy, springy hold-downs  1448  retain the flap in the desired laid-flat, opened orientation, firmly engaged against the underlying feed table supporting surface. The hold downs  1448  can be constructed from any acceptable resilient sheet material including a thin metal, rubber, or another flexible or semi-rigid polymer, cut into a narrow (½-1½-inch) strip. The hold downs  1448  are mounted adjustably on an overlying bar  1449 . They exhibit a slight curve to provide spring force against the underlying surface/flap. 
     With the envelope flap held down, a series of vacuum (suction cup) lifters  1450 , which are fed by independent vacuum lines  1452  move up and down to selectively draw up the opposing non-flap portion side of the envelope. This serves to open the mouth of the envelope for insertion of contents. 
     The transfer station also contains a set of envelope fingers that serve to transition the material from the pusher fingers. When the envelope is pulled open, the envelope fingers, which are uniquely wider than the incoming inserts and have a novel shaped front edge, are driven into the envelope ahead of the insert contents pieces. This insures the envelope is opened sufficiently when the pusher fingers  1410  subsequently drive contents transversely (to the downstream direction) into the pulled-open envelope. 
     The lower side of the non-flap edge (closer to the device front) of the envelope is driven into position as it is held between the belt  1426  and a hold-down bar  1448 . The hold-down bar in this embodiment includes any acceptable clamping mechanism that allows the envelope to be driven along the belt  1426  while sliding against the hold-down bar  1448 . This bar is raised once the envelope is clamped to allow the incoming insert contents room. Once the contents are completely engaged inside the envelope, the hold-own bar returns to its down-and-clamped position. The envelope can eventually exit the outlet  1458  when filled with contents in the next envelope-belt-movement cycle. 
     As the envelope exits the outlet  1458 , it passes under an illustrative wetting brush  1460  arrangement. The wetting brush is fixed in position, slightly higher than the incoming envelope but the flap is driven up into it and drip-fed by a tube  1462  from the overlying reservoir  170  shown above. A valve controls a gravity-feed, or pump-feed, of water from the reservoir  170  to the brush  1460 . This wets the filled envelope flap adhesive as the envelope exits the stuffing station  1428  on the next belt ( 1426 ) cycle. Its flap is then folded by an illustrative folding ramp assembly  1492 . The unique geometry ensures that even if the inserter stops, envelopes with wet flaps will be drawn to the flap closing and sealing section. Note in this embodiment, the liquid reservoir  170  has been placed in a mounting  1464  that is on the opposing side of the control console from the side shown in the view of  FIG. 1 . In practice, the reservoir  170  can be placed at any convenient location on the device and/or console. Notably, in the depicted elevated position, the reservoir is much higher and wider than that of the prior art. This placement ensures that, in the illustrative gravity-fed embodiment, the liquid pressure in the wetting brush is high, and remains relatively constant even as the water level diminishes before refilling the reservoir. 
     In the illustrative embodiment, a series of levers  1466  and thumbscrews  1468  allow the relative width of the downstream inserter components to be varied. In particular, a raised front guide edge  1469 , which restricts transverse movement of the lower (device-front-adjacent) edge of the envelope along the feed path, is adjustable using the screws  1468 . This allows for varying width envelopes to be accommodated. An informed operator can easily readjust both the hopper  126  and downstream components to accommodate differing widths. 
     Notably, prior art insertion devices typically require substantial readjustment of the feed/insertion components of the device to accommodate differing upstream-to-downstream width envelopes due to changes in envelope leading edge registration with respect to their stuffing station (assuming the timing and degree of envelope transport does not vary to accommodate different registration lengths. However, the novel insertion device  100  of this embodiment allows for a very simple upstream-to-downstream registration adjustment due to changes in the fed envelope&#39;s width. In this embodiment, the front/envelope leading edge guide  1470  of the hopper  126  is slidably adjustable along an upstream-to-downstream guide bar  1472  that allows for different envelope widths to be quickly accommodated. The belt  1426  has an upstream edge  1478  that is positioned so that it will engage contents within the expected range of widths to be accommodated. The hopper front guide  1470  is locked into a position along the bar  1472  by a locking screw  1474 . Of course, any acceptable mechanism, including automated (rack-and-pinion, for example) mechanisms, can be used to move and lock the envelope hopper front guide in a desired position. 
     Once the hopper&#39;s front guide  1470  is adjusted to accommodate a given width of envelope, the leading edge of the envelope must be registered to arrive at the appropriate location with respect to the stuffing station  1428 . Otherwise contents will jam because they will not be aligned with the opening. If the location of the leading edge changes, but the point at which the envelope becomes grasped by the belt  1426  does not change, then the envelope will arrive out of phase with the stuffing station. One solution would be to change the length of the belt cycle in view of change in front guide location. However, a more reliable solution is to maintain a constant cycle length of the belt  1426  for all envelope widths, and to change the timing upon which different sized enveloped become grasped by the belt (which may already be in motion for a small time) once they are delivered from the hopper  126  by the pusher finger  1441 . The phasing of entry onto the belt is, thus, adjusted by moving a weighted clamp bar  1490 , which overrides the belt in an upstream-to-downstream direction use of the locking screw  1480  that engages an adjustment slide bar  1478 . In this manner, the weighted clamp bar  1490  can be set at a predetermined in an upstream to downstream direction. The attached flap plow assembly  1444  is likewise movable with the clamp bar. In this manner so that the upstream-to-downstream registration of the flap plow can also be adjusted. The upstream edge of the clamp bar engages the belt with a clamp nip (denoted by the “X”  1494 ) that, with the appropriate timing, initiates grasping of the leading edge of an envelope and subsequent driving of the envelope downstream to the stuffing station  1428 . Explained briefly, the belt  1426  in this embodiment always moves the same distance value with each cycle. Likewise, the pusher always drives the trailing edge of the envelope from the bottom of the hopper  126  with the same synchronized timing as the belt&#39;s movement. Thus, by changing where the nip  1494  first engages the leading edge of the fed envelope, the final location of the leading edge when the belt stops moving can be accurately regulated/registered. This allows the leading edge to arrive at the correct, registered location with respect to the stuffing station  1428  when the belt stops. A grasping nip can be constructed in a variety of ways. In one embodiment, the nip comprises a weighted roller or ball contained within the bar  1490  that contacts the belt  1426 . However, it is expressly contemplated that any mechanism that allows the belt or other transport mechanism to grasp the envelope leading edge, and thereafter carry it downstream at the appropriate time and phasing, can comprise a nip in accordance with this invention. 
     The upstream/downstream adjustment of the clamp bar  1490  and associated nip  1494  can be accomplished in a variety of manual and/or automated ways. For example, in an alternate embodiment a drive screw attached to a servo motor (or other controllable actuator) can be used to apply predetermined adjustments in view of the position of the hopper front guide  1470 . Likewise, the clamp bar may remain relatively stationary in an alternate embodiment, while the location of the grasping surface or nip is adjusted in an upstream to downstream direction. 
     In summary it should be clear that the above-described components, mechanisms and procedures afford superior performance, ease of maintenance, servicing and adjustment to the overall envelope insertion device described herein. 
     The foregoing has been a detailed description of illustrative embodiments of the invention. Various modifications and additions can be made without departing from the spirit and scope if this invention. Each of the various embodiments described above may be combined with other described embodiments in order to provide multiple features. Furthermore, while the foregoing describes a number of separate embodiments of the apparatus and method of the present invention, what has been described herein is merely illustrative of the application of the principles of the present invention. For example, the shape, size and layout of the housing and various components are each highly variable. Likewise, in alternate embodiments certain components can be separately powered by additional electronic or fluid-driven motors. The materials employed for various components can be widely varied as well. Accordingly, this description is meant to be taken only by way of example, and not to otherwise limit the scope of this invention.