Patent Publication Number: US-8540227-B2

Title: Accumulating apparatus for discrete paper or film objects and related methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the filing date priority benefit of U.S. Patent Application Ser. No. 61/167,026, filed Apr. 6, 2009 entitled “Accumulating Apparatus for Discrete Paper or Film Objects and Related Methods,” the disclosure of which is expressly incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention generally relates to converting equipment and, more particularly, to apparatus for converting paper into sheets, collating and automatic envelope stuffing operations. 
     BACKGROUND 
     Converting equipment is known for automatically stuffing envelopes. Such equipment may include components for feeding a pre-printed web of paper, for cutting such web into one or more discrete sheets for collating sheets, and for feeding such discrete sheet collations into envelopes. Such equipment may further include components to convey the stuffed envelopes to a specified location. The industry has long known apparatus which accomplish these and other functions. However, improvements are needed where high volumes of paper piece count and high speeds are required without sacrificing reliability, accuracy and quality of end product. 
     More particularly, a large roll of paper is typically printed in discrete areas with piece specific information. That is, the initial roll of paper comprises vast numbers of discrete areas of already-printed indicia-specific information with each discrete area defining what is to eventually comprise a single page or sheet of indicia specific information. To complicate the process, a variable number of sheets with related indicia must be placed into the envelopes so that the content of one envelope varies from the content of another by sheet count and, of course, by the specific indicia on the included sheets. As one example, financial reports of multiple customers or account specifics may require a varied number of customer or account specific sheets to be cut, respectively collated, stuffed and discharged for delivery. Thus, the contents of each envelope include either a single sheet or a “collation” of from two to many sheets, each “collation” being specific to a mailing to an addressee. 
     In such an exemplary operation, a financial institution might send billing or invoice information to each of its customers. The billing information or “indicia” for one customer may require anywhere from one final sheet to a number of sheets which must be collated, then placed in that customer&#39;s envelope. While all this information can be printed in sheet size discrete areas, on a single roll, these areas must be well defined, cut, merged or collated into sheets for the same addressee or destination, placed into envelopes, treated and discharged. Thus, a system for conducting this process has in the past included certain typical components, such as a paper roll stand, drive, sheet cutter, merge unit, accumulate or collate unit, folder, envelope feeder, envelope inserter, and finishing and discharge units. Electronic controls are used to operate the system to correlate the functions so correct sheets are collated and placed in correct destination envelopes. 
     In such multi-component systems, the pass-through rate from paper roll to finished envelope is dependent on the speed of each component, and overall production speed is a function of the slowest or weakest link component. Overall reliability is similarly limited. Moreover, the mean down time from any malfunction or failure to repair is limited by the most repair-prone, most maintenance consumptive component. Such systems are capital intensive, requiring significant floor plan or footprint, and require significant labor, materials and maintenance capabilities and facilities. 
     In such a system, it is sometimes necessary to accumulate folded or unfolded discrete inserts made of paper or film while another operation takes place. For example, and without limitation, a particular batch or job may require stuffing an envelope with a relatively high number of folded inserts, such as 20, while a folding apparatus that is part of the system can only handle 10 inserts at a time. In such situation, it may be necessary to accumulate the inserts thereby forming a first stack of 10 inserts and feed the stack to the folder for processing while forming and thereby accumulating a second stack of 10 inserts for subsequent feeding to the folder. 
     Conventional apparatus used for accumulating discrete objects may include a pair of rollers in confronting relationship and contacting one another, with the discrete inserts being fed towards and held by the rollers which are typically stopped. As the stack of inserts forms and the thickness thereof increases beyond a certain magnitude, the resulting stack is staggered (i.e., in cascade fashion), for example such that each leading edge of the inserts follows the general circumference of one of the rollers, at a slightly different position, causing each successive sheet to stop slightly behind the leading edge of the preceding sheet. The resulting stack of inserts, accordingly, is one where one or more of the leading edges of the sheets do not coincide with one another, which may lead to handling problems downstream in the direction of travel of the stack. 
     In accumulating a stack of objects such as discrete paper sheets, it is desirable for the leading edges of the sheets to be in, or form, a flat leading edge of the accumulated stack and not to be staggered at different positions relative to each other. In the past, paper feeders such as rollers, tended to form stacks with such staggered or inclined leading edges. 
     Accordingly, it is desirable to provide an improved apparatus and related methods for accumulating discrete paper or film objects such as sheets in a high speed handling machine. It is also desirable to provide a transportation system and related methods that address inherent problems observed with conventional paper systems. Moreover, it is desirable to provide a converting apparatus in the form of an automatic envelope stuffing machine that address the problems of conventional machines for stuffing envelopes, such as the formation of stacks of inserts with staggered edges. 
     SUMMARY 
     To these ends, in some embodiments, an apparatus accumulates discrete paper or film objects to thereby form a stack with a uniform rather than a staggered profile, and which may include accumulator elements that accelerate to match a required speed downstream in the direction of travel of the objects. 
     More particularly, in one specific embodiment of the invention, an apparatus is provided for accumulating discrete paper or film objects traveling in a machine direction. A first accumulator element of the apparatus is rotatable about a first axis of rotation. A second accumulator element is disposed in confronting relationship with the first accumulator element and has a first, generally flat surface, and a first arcuate surface. Both of these surfaces are rotatable about the first axis of rotation and the first accumulator element has a first angular position that defines a first gap relative to the second accumulator element for receiving the objects there between. The first accumulator element has a second angular position that defines a second gap relative to the second accumulator element for moving the objects in the machine direction, with the second gap being smaller than the first gap. A stop of the apparatus is oriented transverse to the first axis of rotation and rotates about that first axis. The stop is configured to prevent movement of the objects in the machine direction when the first accumulator element is in the first angular position. 
     In another embodiment, an apparatus is provided for accumulating discrete paper or film objects traveling in a machine direction. The apparatus includes a first cam and a second cam. The first cam is rotatable about a first axis of rotation and the second cam is rotatable about a second axis of rotation that is generally parallel to the first axis of rotation. The second cam is disposed in confronting relationship with the first cam. The apparatus also includes a first stop that is oriented transverse to the first axis of rotation and which is rotatable thereabout. A second stop is oriented transverse to the second axis of rotation and is rotatable about that second axis. The first and second cams have a first common angular position that defines a first gap between them, and a second common angular position that defines a second gap between the cams. The first gap is wider than the second gap and is configured to receive the objects there between, and the second gap is effective to nip the objects there between to move the objects in the machine direction. The first and second stops are configured to prevent movement of the objects in the machine direction when the objects are received in the first gap. 
     In another embodiment, an automatic converting apparatus is provided. The converting apparatus has a first end that is associated with feeding of a roll of paper in a machine direction, a portion configured to process the roll of paper into discrete paper objects, and a second end associated with feeding of envelopes toward the discrete objects. The converting apparatus also has an accumulating apparatus that is configured for accumulating the discrete objects traveling in the machine direction. The accumulating apparatus includes first and second accumulator elements disposed in confronting relationship with one another. The first accumulator element is rotatable about a first axis of rotation and has a first angular position that defines a first gap relative to the second accumulator element for receiving the discrete objects there between. The first accumulator element also has a second angular position that defines a second gap relative to the second accumulator element for nipping and moving the discrete objects in the machine direction. The second gap is smaller than the first gap. The accumulating apparatus also has a stop that is oriented transverse to the first axis of rotation and which is rotatable about that first axis. The stop is configured to prevent movement of the discrete objects in the machine direction when the first accumulator element is in the first angular position. 
     In yet another embodiment, a paper sheet stacking apparatus is provided. The apparatus includes an accumulator element that has an abutting surface defining first and second paper receiving nips, with the first nip being wider than the second nip. The stacking apparatus also has a stop for blocking leading edges of successively fed paper sheets in generally the same position and thereby form a stack of sheets having a generally uniform leading edge. The sheets are dispensed within the first nip. The accumulator element may be rotatable to define the second nip for engaging and driving the formed stack in a downstream direction. 
     In another embodiment, a method is provided for accumulating discrete paper or film objects traveling in a machine direction. The method includes defining a first gap between first and second accumulator elements to receive the objects there between, the first gap being associated with a first angular position of the first accumulator element. The first accumulator element is rotated to define a second gap between the accumulator elements and which is associated with a second angular position of the first accumulator element. The second gap is smaller than the first gap and engagement of the objects with surfaces defining the second gap is effective to move the objects in the machine direction. Movement of the objects traveling in the machine direction is blocked when the objects are received in the first gap. 
     In yet another embodiment, a method is provided for accumulating a plurality of paper or film objects. A first one of the objects is moved in a machine direction into a space defined between a pair of rotatable accumulator elements that are in a non-rotating angular position. A second one of the objects is then moved toward a position above or below the first object to thereby form a stack of the objects. The stack of the objects is supported with an apparatus downstream from the accumulator elements and which is operable to move the stack in the machine direction at a first speed. Rotation of the accumulator elements is accelerated from the non-rotating position to a transfer position in which the stack of the objects is moving substantially at the first speed of the apparatus downstream and the stack of the objects is transferred away from engagement with the accumulator elements and into engagement with the apparatus downstream thereof. 
     Such apparatus and methods are particularly useful in a paper converting and envelope stuffing system contemplating improved paper converting and sheet inserting apparatus and methods, modular based, and having improved paper handling apparatus, servo driven components, improved sensor density and improved control concepts controlling the system operation. One or more of the embodiments of the invention contemplate the provision of an improved envelope conveying apparatus which can be used as a module of a modular paper converting and sheet insertion system where human capital, required space, required equipment, maintenance, labor and materials and facilities therefore are reduced compared to conventional systems of similar throughput. 
     More specifically, such improved apparatus and methods contemplate a plurality of functional modules providing the following functions in a series of modules of like or dissimilar modules where a specific module is multi-functional. The functions comprise:
         printed paper roll handling/unwinding;   paper slitting and cutting;   sheet collation and accumulation;   sheet folding;   transportation for interfacing with inserts;   envelope feeding;   collation interfacing and insertion; and   envelope treating and discharge.       

     More particularly, one or more aspects of the invention may contemplate, without limitation, new and unique apparatus and methods for:
         (a) guiding a web of the paper or film containing the printed indicia into a cutter apparatus;   (b) processing the web through slitting and transverse-cutting operation;   (c) transporting and merging discrete pieces of the insert;   (d) accumulating predefined stacks of discrete pieces of the insert;   (e) guiding and transporting a stack of discrete pieces of the insert toward an envelope-filling station;   (f) transporting individual envelopes toward the envelope-filling station;   (g) creating and processing a stack of the envelopes prior to the envelope-filling process; and   (h) processing an individual envelope from the stack of envelopes and through the envelope-filling station.       

     While the combination of the particular functions in the particular modules are unique combinations, the invention of this application lies primarily in the paper transporting apparatus and methods described herein. 
     In accordance with various embodiments of this invention, a plurality of objects such as paper sheets are sequentially fed to a nip or gap formed between two paper conveying, intermittently accumulator elements. Respective surfaces of the elements are rebated from the circumference of the curvilinear edges so that the nip or gap formed between the rebated edges is larger than the nip or gap formed by the circumferential edges. Paper sheets are fed to one or more stops between the larger nip where a stack having a flush, smooth leading edge, is formed in the larger nip. Thereafter, the accumulator elements are driven to engage and drive the whole stack, with a smooth flat leading edge, in a machine direction for further processing of the stack. 
     In some embodiments, the stop or stops comprise fingers radially extending from either or both of the accumulator elements or their drive axles in a predetermined angular position so as to stop leading edges of successively introduced sheets at generally the same location before the stack is conveyed further by the accumulator elements. 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
         FIG. 1  is a perspective view illustrating a portion of a converter for stuffing envelopes with selected paper or film objects. 
         FIG. 2  is a perspective view of an interior portion of an accumulating apparatus associated with the encircled area of  FIG. 1 . 
         FIG. 3  is a perspective view of a portion of the transporting apparatus of  FIG. 2 . 
         FIG. 4  is a perspective view of the accumulating apparatus of  FIGS. 2 and 3  illustrating the apparatus relative to a discrete paper or film object. 
         FIG. 5  is an elevation view of a portion of the accumulating apparatus of  FIGS. 2-4 . 
         FIG. 6  is an elevation view similar to  FIG. 5  showing a pair of accumulator elements of the accumulating apparatus in respective orientations different from those of  FIG. 5 . 
         FIG. 7  is an elevation view similar to  FIGS. 5 and 6 , showing the accumulator elements in an orientation different from those of  FIGS. 5 and 6 . 
         FIG. 8  is an elevation view of another embodiment of an accumulating apparatus. 
         FIG. 9  is an elevation view of yet another embodiment of an accumulating apparatus. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the figures and, more particularly to  FIG. 1 , a portion of an exemplary converter  10  is illustrated for processing a web  12  of paper or film. Although not shown, the web  12  processed by the converter  10  originates, for example, from a roll (not shown) of material containing such web  12 . The roll is generally associated with a first end  14  of the converter  10  and is unwound in ways known in the art, for example, by driving a spindle receiving a core of the roll or by contacting a surface of the roll with a belt or similar apparatus. Typically, the web  12  is pre-printed with indicia in discrete areas. 
     The web  12  thus travels in a machine direction, generally indicated by arrow  15 , through several modules that make up the converter  10 . In the exemplary embodiment of  FIG. 1 , converter  10  cuts the web material into discrete sheets (corresponding to the “areas”) of material (“inserts”) and feeds them into envelopes fed generally from an opposite end  16  of converter  10 . Converter  10  may further convey the envelopes containing the inserts away from the shown portion of the converter  10  for subsequent processing or disposition. The exemplary converter  10  includes, as noted above, several modules for effecting different steps in the processing of the web  12  and the inserts resulting therefrom, as well as processing of the envelopes. Those of ordinary skill in the art will readily appreciate that converter  10  may include other modules in addition or instead of those shown herein. 
     A first of the shown modules, for example, is a cutting module  30  relatively proximate first end  14  of the converter  10  and which cuts the web  12  into discrete objects such as inserts ( FIG. 2 ) for subsequent processing. A conveying module  40  controls and transports the discrete inserts received from the cutting module and feeds them into a folding and buffering module  50 . Module  50  may, if necessary, form stacks of the discrete inserts for subsequent processing, for example, if the intended production requires stuffing the envelopes with inserts defined by more than one discrete sheet. Module  50  folds the discrete inserts, if required by the intended production, along a longitudinal axis of the discrete inserts disposed generally along the machine direction. Moreover, module  50  accumulates, collates or buffers sets of the discrete sheets into individually handled stacks, if the particular production so requires. 
     With continued reference to  FIG. 1 , an uptake module  60  takes the inserts from folding and buffering module  50  and cooperates with components of a stuffing module  70  to transport the inserts and feed them into envelopes. The envelopes, in turn, are handled and fed toward the stuffing module  70  by an envelope conveyor  80 . A conveying assembly  90  is operatively coupled to the stuffing module  70  and the envelope conveyor  80  for conveying the stuffed or filled envelopes away from the shown portion of converter  10  for subsequent processing or disposition. 
     With reference to  FIGS. 2-7 , and with particular reference to  FIGS. 2-3 , an interior of the folding and buffering module  50  is illustrated. Module  50  includes an accumulating apparatus  100  having a plurality of belts  104   a ,  104   b  for feeding discrete film or paper objects  110  toward two sets of rotatable accumulator elements  113   a ,  115   a  and  113   b ,  115   b  of the accumulating apparatus  100 . In this regard, the belts  104   a ,  104   b  are driven by pulleys  116  that have respective grooves  118  on their circumferential surfaces, which allow the belts  104   a ,  104   b  to ride on and be secured relative to the pulleys  116 . The pulleys  116 , in turn, are driven by drive shafts  120  coupled to one or more drives (not shown) that selectively rotate the shafts  120 . Movement of the belts  104   a ,  104   b  generally along their respective length dimensions result in movement of the discrete objects  110  in the machine direction (arrow  130 ). Respective pairs of top and bottom belts  104   a ,  104   b  are spaced from one another so as to engage and move the objects  110  in the machine direction (arrow  130 ) toward the two sets of accumulator elements  113   a ,  115   a  and  113   b ,  115   b . As explained in further detail below, a plurality of adjustable ramps  132  of the apparatus  100  can direct the vertical position of each of the objects  110  relative to other ones of the objects  110  as the objects  110  travel toward the accumulator elements  113   a ,  115   a  and  113   b ,  115   b.    
     With particular reference to  FIG. 3 , the accumulating apparatus  100  has a first set of accumulator elements  113   a ,  113   b  laterally spaced from one another and which are respectively in confronting relationship relative to a second opposed set of accumulator elements  115   a ,  115   b . Each of the accumulator elements  113   a ,  113   b  of the first set, in this embodiment, is in the general form of a cam having at least one generally flat surface  144   a ,  144   b  and an arcuate surface  146   a ,  146   b . The accumulator elements  113   a ,  113   b  of the first set are mounted on a first common shaft  150  and therefore rotate about a first axis  150   a  of the shaft  150  in the general direction of arrow  152 , while the accumulator elements  115   a ,  115   b  of the second set are mounted on a second common shaft  156  and rotate about a second axis  156   a  that is generally parallel to the first axis  150   a . The first and second common shafts  150 ,  156  are operatively coupled to a schematically-depicted drive  126  that is actuatable to rotate the accumulator elements  113   a ,  113   b ,  115   a ,  115   b  to predetermined angular positions. As explained in further detail below, rotation of the accumulator elements  113   a ,  113   b ,  115   a ,  115   b  causes nipping engagement of the arcuate surfaces  146   a ,  146   b  with the object  110 , such that, when engaged, the accumulator elements  113   a ,  113   b ,  115   a ,  115   b  drive the object  110  in the machine direction (arrow  130 ). As shown in  FIG. 3 , rotation of the pulleys  116  (arrows  162 ) is such that they drive movement of several pairs of confronting top and bottom belts  104   a ,  104   b  also in the machine direction (arrow  130 ), with movement of each pair of confronting belts  104   a ,  104   b , and particularly their engagement with the objects  110 , in turn, moving the objects  110  also in the machine direction (arrow  130 ). 
     With particular reference to  FIG. 4 , movement of the object  110  in the machine direction (arrow  130 ) is blocked (i.e., stopped) by one or more stops of the apparatus  50 . The illustrated embodiment has one or more pairs of stops  172 ,  174  in the form of top and bottom plates that are respectively oriented transverse to the first and second axes of rotation  150   a ,  156   a . More specifically, the stops  172 ,  174  are aligned generally in the same plane with one another such as to define a positive stop that contacts the leading edge  110   a  of each of the objects  110  as the objects  110  move into a nip or gap  184  defined between each pair of confronting ones of the accumulator elements  113   a ,  113   b ,  115   a ,  115   b . In operation, once an object  110  is stopped by the stops  172 ,  174 , continuous movement of the top and bottom belts  104   a ,  104   b  results in the top and bottom belts  104   a ,  104   b  slipping relative to the object  110 . In an alternative embodiment (not shown), it is contemplated that the belts  104   a ,  104  may instead be positioned so as not to extend as illustrated, but rather extend to a location upstream of the gap  184 . In that alternative embodiment, once the object  110  is stopped in front of the gap  184 , there is no further contact between the belts  104   a ,  104   b  such that continuous movement of the belts  104   a ,  104   b  does not result in slippage thereof relative to the object  110 . 
     With particular reference to  FIGS. 5 ,  5 A,  5 B,  6 , and  7 , an exemplary operation of the accumulating apparatus  100  is illustrated. For ease of understanding, the figures and their description refer only to one pair of confronting accumulator elements  113   a ,  115   a , noting that the same principles may generally apply to the other pair of opposed accumulator elements  113   b ,  115   b  shown in  FIGS. 2-4 . The accumulator elements  113   a ,  115   a  of the first pair are in the form of top and bottom accumulator elements  113   a ,  115   a  depicted in  FIG. 5  in a first common, non-rotating angular position. In this first or home angular position, the flat surface  144   a  of the top accumulator element  113   a  is in general confronting relationship with the flat surface  144   a  of the bottom accumulator element  115   a , thereby defining a vertical space d 1  of the gap  184  between the top and bottom accumulator elements  113   a ,  115   a . In this first common angular position of the top and bottom accumulator elements  113   a ,  115   a , the two stops  172 ,  174  are shown in general alignment with one another (i.e., they are coplanar) so as to provide a positive stopping or blocking surface preventing forward movement of the object  110  in the machine direction (arrow  130 ). Accordingly, a first object  110  advances into the gap  184  toward the stops  172 ,  174 , with further movement of the object  110  in the machine direction (arrow  130 ) being prevented by the stops  172 ,  174 . In one aspect of this embodiment, the top and bottom accumulator elements  113   a ,  115   a  are stopped in this first common angular position, to thereby define a home position for the top and bottom accumulator elements  113   a ,  115   a . Movement in the machine direction (arrow  130 ) of additional objects will result in the formation of a stack of the objects  110 , the leading edges  110   a  of which will be in general vertical alignment with one another and abutting one or both of the stops  172 ,  174 . 
     With particular reference to  FIG. 5A , a second object  190  is illustrated moving in the machine direction (arrow  130 ) toward the gap  184 , and more specifically, toward the stops  172 ,  174 . Advancement in the machine direction (arrow  130 ) of this second object  190  is similarly blocked by the stops  172 ,  174  that prevent forward movement of the first object  110 . As suggested by the object drawn in phantom, the second object  190  may alternatively be stacked over or under the first object  110 . In this regard, adjustment of the ramp elements  132  ( FIG. 2 ) determine whether the second object  190  is stacked over or under the first object  110 . The ramp element  132  may, for example, be manually adjustable or alternatively automatically adjustable to thereby determine which of the two directions (i.e., above or below the first object  110 ) is followed by the second object  190 . 
     With particular reference to  FIG. 5B , an exemplary stack S of first, second and third objects  110 ,  190 ,  200  is shown being formed in the gap  184  between the top and bottom accumulator elements  113   a ,  115   a  and in front (i.e., upstream) of the stops  172 ,  174 . As  FIG. 5B  illustrates, the respective leading edges  110   a ,  190   a ,  200   a  of the first, second and third objects are generally aligned with one another, which thereby results in the formation of a generally uniform stack, which facilitates the handling of the stack downstream of the top and bottom accumulator elements  113   a ,  115   a . While  FIG. 5B  illustrates a stack of three objects  110 ,  190 ,  200 , it is contemplated that a stack of any number of objects may be alternatively formed, with the resulting thickness t of the stack S being only limited by the size d 1  of the gap  184 . 
     With particular reference to  FIG. 6 , the top and bottom accumulator elements  113   a ,  115   a  are shown having rotated (arrows  204 ) to a second angular position of the top and bottom accumulator elements  113   a ,  115   a  so as to cause nipping engagement of the arcuate surfaces  146   a ,  146   b  with the stack S of the objects  110 ,  190 ,  200 . In this regard, further rotation of the top and bottom accumulator elements  113   a ,  115   a  causes advancement of the stack S in the machine direction (arrow  130 ) towards a schematically depicted apparatus  250  downstream therefrom. The apparatus  250  may, for example and without limitation, be a pair of rollers or a belt supporting the stack S and operable to move the same in the machine direction (arrow  130 ). In the second angular position of the top and bottom accumulator elements  113   a ,  115   a , the top and bottom accumulator elements  113   a ,  115   a  define a second vertical space d 2  of the gap  184  that is smaller than the first vertical space d 1  of gap  184  associated with the first angular position ( FIG. 5 ) i.e., or stated differently, the accumulator elements  113   a ,  115   a  define a second, smaller gap  284 . Rotation from the first angular position of  FIG. 5  to the second angular position of  FIG. 6  in this embodiment is effected at a first speed, which could, for example, be suitably chosen to gently engage the stack S. 
     With particular reference to  FIG. 7 , a third angular position of the top and bottom accumulator elements  113   a ,  115   a  is shown which is different from the first and second angular positions ( FIGS. 5 and 6 ). This third angular position is such that the stack S is substantially (i.e., almost completely) discharged from engagement with the top and bottom accumulator elements  113   a ,  115   a  and is advanced toward the apparatus  250  downstream of the accumulator elements  113   a ,  115   a . In this exemplary embodiment, the speed of rotation of the accumulator elements  113   a ,  115   a  from the second angular position ( FIG. 6 ) to the third angular position ( FIG. 7 ) is effected at a second speed that may be greater or less than the first speed from the first angular position of  FIG. 5  to the second angular position of  FIG. 6 . More specifically, the top and bottom accumulator elements  113   a ,  115   a  may for example be accelerated or decelerated from the second angular position ( FIG. 6 ) to the third angular position ( FIG. 7 ) so as to match a speed of the apparatus  250  downstream of the top and bottom accumulator elements  113   a ,  115   a , depending of the speed of the apparatus  250 . To this end, one or both of the top and bottom accumulator elements  113   a ,  115   a  may be driven by a suitably chosen drive or motor, such as a servo motor  252 , that is configured to rotate the top and bottom accumulator elements  113   a ,  115   a  at variable speeds. 
     It is also contemplated that rotation of the accumulator elements  113   a .  115   a  may be accelerated from the first angular position ( FIG. 5 ) to the second angular position ( FIG. 6 ) at a first acceleration rate and from the second angular position ( FIG. 6 ) to the third angular position ( FIG. 7 ) at a second acceleration rate different from (e.g., greater or less than) the first acceleration rate. In addition, the accumulator elements  113   a ,  115   a  rotate from the third angular position ( FIG. 7 ) or from a fourth angular position (not shown) in which there is no further engagement with the stack S back to the first angular position ( FIG. 5 ). In specific embodiments, this last rotation from the third or fourth angular positions back to the first angular position may be effected at a speed that is greater than any or all of the speeds associated with rotation of the accumulator elements  113   a ,  115   a  between the first to the second, second to the third, or third to the fourth angular positions. This relatively quick return of the accumulator elements  113   a ,  115   a  to the first angular position increases the throughput of the accumulating apparatus  100  by minimizing the time in which the accumulating apparatus  100  is not in position to receive objects  110  into the gap  184 . 
     Additionally, the accumulating apparatus  100  may include a sensor  260  that may sense the speed of the apparatus  250  downstream of the top and bottom accumulator elements  113   a ,  115   a  and feed the sensed speed to a control unit  272  that controls the speed of the motor  252 . In addition or alternatively to the above, the accumulating apparatus  100  may also include a sensor  280  that senses the thickness t of the stack S held in front of the gap  184 , and feed the sensed thickness to the control unit  272 , to thereby control the magnitude of the first speed of rotation from the first angular position ( FIG. 5 ) to the second angular position ( FIG. 6 ) so as to gently engage the objects  110  forming the stack S. 
     Those of ordinary skill in the art will readily appreciate that the same principles described above may be applicable to variations of the apparatus described with respect to the above figures. For example, and without limitation, the accumulating apparatus  100  may include a single stop  172 , for example, extending only from the top accumulator element  113   a , rather than a pair of stops  172 ,  174  extending respectively from the top and bottom accumulator elements  113   a ,  115   a . Likewise, while the embodiments of the preceding figures include pairs of accumulator elements (e.g.,  113   a ,  115   a ) in the form of cams, it is contemplated that an alternative apparatus may include only the top or bottom accumulator element  113   a ,  115   a  having such shape (e.g., having a flat surface  144   a ,  144   b ) and cooperating with a roller rather than with a cam disposed in confronting relationship therewith. Moreover, while the preceding figures show two pairs of top and bottom accumulator elements ( 113   a ,  115   a  and  113   b ,  115   b  respectively) that are laterally spaced from one another, it is contemplated that an alternative accumulating apparatus may have any number of pairs of opposed accumulator elements other than the two that are shown in the preceding figures. 
     Materials defining the accumulator elements  113   a ,  115   a ,  113   b ,  115   b  are suitably chosen. For example, one or more of the accumulator elements  113   a ,  115   a ,  113   b ,  115   b  may be made of a relatively hard and/or lightweight material, such as a foam-based material or a foam-like material. Additionally, one or more of the accumulator elements  113   a ,  115   a ,  113   b ,  115   b  may include a coating such as a urethane coating on their surfaces, to thereby provide a predetermined level of hardness and durability to the accumulator elements  113   a ,  115   a ,  113   b ,  115   b . In addition, other design considerations may be suitably chosen. For example, in this particular embodiment, each of the accumulator elements  113   a ,  115   a ,  113   b ,  115   b  has a plurality of voids  294  that minimize the overall weight of the accumulator elements  113   a ,  115   a ,  113   b ,  115   b . The voids  294  also facilitate flexing of the accumulator elements  113   a ,  115   a ,  113   b ,  115   b  resulting from their compression when they nip the object  110  or stack S of objects s of  110 . This flexibility permits the accumulator elements  113   a ,  115   a ,  113   b ,  115   b  to generally conform with the thickness of the stack S, which facilitates gentle but effective engagement of the stack S and the forward movement thereof resulting from rotation of the accumulator elements  113   a ,  115   a ,  113   b ,  115   b  from the first angular position ( FIG. 5 ) to the second angular position ( FIG. 6 ). In embodiments in which the accumulator elements  113   a ,  115   a ,  113   b ,  115   b  are made of a foam-based material or a foam-like material, the porosity of that material also facilitates flexing of the accumulator elements  113   a ,  115   a ,  113   b ,  115   b  resulting from their compression associated with nipping engagement of the object  110  or stack S of objects s of  110 . 
     With reference to  FIGS. 8 and 9 , respective alternative embodiments of accumulating apparatus  300 ,  302  are illustrated. For ease of understanding, like reference numbers in  FIGS. 8 and 9  refer to like features in the preceding figures. With particular reference to  FIG. 7 , the apparatus  300  includes a first plurality of ramp elements  132  (only one shown) located upstream of a second plurality of ramp elements  310  (only one shown). The ramp elements  132  and  310  are mounted on a common bracket  312  to simultaneously adjust their position in the machine direction (arrow  130 ) to accommodate objects  110  of different pitch (i.e., length). In the view shown ( FIG. 8 ), the trailing edge  110   b  of the object  110  rests generally against the first ramp elements  132 , with every subsequent object being directed above an object  110  resting in front of the gap  184  and having its trailing edge  110   b  generally behind the first ramp elements  132 . The upward orientation of each of the ramp elements  132  facilitates directing of the subsequent objects  110  above objects  110  resting as described above. The second ramp elements  310 , meanwhile, direct the leading edge  110   a  of each of the objects  110  downward as they travel in the machine direction (arrow  130 ) toward the gap  184 . In this embodiment, mounting of the first ramp elements  132  onto the bracket  312  is such that their vertical position may be adjusted so that only the second ramp elements  310  act upon the objects  110 . In this regard, the second ramp elements  310  direct the objects  110  downward, thereby causing every subsequent object  110  to go under objects  110  already in the stack S. In another aspect of this embodiment, a pulley  116   a  is hingedly coupled to the apparatus  300  such that the upper belt  104   a  driven by pulley  116   a  may easily flex in response to the thickness of the objects  110 . Flexing of the belt  104   a  in this embodiment may, for example, be in the range of up to 14 mm. 
     With reference to the exemplary embodiment of  FIG. 9 , the illustrated apparatus  302  includes no second ramp elements  310  at all, but rather a first plurality of ramp elements  132  and a support plate  330  disposed between the top and bottom belts  104   a ,  104   b  to support the object  110 . This support plate  330  may be desirable, for example, to minimize the frictional forces experienced by the objects  110  associated with slipping movement in the machine direction (arrow  130 ) of the belts,  104   a ,  104   b  relative to the objects  110 , as the objects  110  are blocked from forward movement by the stops  172 ,  174  ( FIG. 5 ). 
     While the present invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the general inventive concept.