Abstract:
An apparatus for decelerating signatures moving in tandem fashion through sheet processing equipment is provided. A pair of counter-rotating cams lying in general face-to-face relation along a travel path of the signatures reach into the travel path of the signatures to effectively grab the trailing end of each signature so as to decrease the speed of each signature as the signature continues or to further processing equipment in the sheet handling system. 
     Also provided is a guide assembly which increases control over the signatures during the decelerating process and during transport of the signatures to further downstream processing equipment. 
     The guide assembly includes grooved rollers which act as pulleys for belts near the exit stream of the slow-down equipment, wherein the protruding segments between belt grooves act to push the signatures away from the belt. 
     Alternatively, or in combination, the guide assembly includes air nozzle means for impinging at least one stream of air parallel to, and/or at an obtuse angel to, the path of signature travel, which assists in keeping the signatures from opening out during delivery to further processing equipment. 
     Also disclosed is a timing belt means for correlating the rotation of the pair of opposed cams.

Description:
FIELD OF THE INVENTION 
     The present invention relates, generally, to sheet processing equipment for transporting signatures moving in serial fashion along a path to one of a plurality of collation paths and, more particularly, to sheet processing equipment for collation of printed signatures to be used in the binding of a publication such as a magazine or a newspaper. The present invention relates to an apparatus for decelerating substantially evenly spaced apart successive signatures found in a stream of fast moving signatures for delivery of the signatures to a subsequent process such as a rotary fan delivery device. The present invention also relates to an apparatus for guiding successive signatures from a slow down mechanism of the foregoing kind to a downstream destination such as a rotary fan delivery device. The present invention provides an improved signature delivery system for a high speed printing press which allows for increased operating speeds with fewer jams while, at the same time, reducing or preventing damage to the signatures as the signatures travel through sheet processing equipment. 
     BACKGROUND OF THE INVENTION 
     Sheet processing equipment contemplated herein may range from apparatus associated with an office copier, to sheet or web handling devices employed in the manufacture of paperboard articles, to sheet processing equipment specifically adapted to process signatures to be used in binding or otherwise assembling books, magazines or newspapers. Each of these environments presents a somewhat different challenge in designing an efficient collator or delivery system, but the same objective applies to the entire class of apparatus, namely, accurately routing selected flexible webs or ribbon sections along a desired collation path to achieve a desired order. 
     In the printing industry, an image is repeatedly printed on a continuous web or substrate such as paper. The ink is dried by running the web through curing ovens. In a typical printing process, the web is subsequently slit (in the longitudinal direction which is the direction of web movement) to produce a plurality of continuous ribbons. The ribbons are aligned one on top of the other, folded longitudinally, and then cut laterally to produce a plurality of multipaged, approximately page length web segments, termed signatures. A signature can also be one printed sheet of paper that has or has not been folded. It is often desirable to transport successive signatures in different directions along different paths in order to increase the overall operating speed and versatility of the printing process. In general, a sheet diverter operates to route fast moving signatures along a desired one of a plurality of paths as the signatures continue on to the next step in the signature processing system. 
     Printing press systems are operable at high speeds, typically in excess of 2,000-3,000 feet per minute (fpm). It is often desirable to run printing press equipment at the highest speeds possible in order to produce as many printed products as possible in a given amount of time. Because printing presses operate at high speeds, it is usually, if not always, necessary to reduce the speed of the signatures in the delivery system in order to shingle and to square the signatures and eventually stack the signatures. Various delivery systems for decelerating and shingling signatures are set forth in the prior art. 
     SUMMARY OF THE INVENTION 
     A system which employs a rotary fan delivery system is found after signature decelerating equipment to individually collect the signatures and subsequently pass each signature to a conveyor, such as a shingling conveyor. Generally, signatures are caused to fall or move into a receptive slot in the rotating fan-like delivery means. As the rotary fan rotates, the signatures fall out one after the other typically onto a slow moving conveyor in an overlying or shingled arrangement. Without signature decelerating equipment, in order to avoid damage to the signatures as the signatures are thrown into the respective slots of the rotary fan device, the speed of each signature must be generally slowed down by running the printing press and folder at a slower rate of speed so that the impact force of the leading edge of the signature against a dead end surface of the slot is reduced. Thus, without a slow down mechanism, reduced operating speeds limit the overall output of the printing system. 
     A problem which may occur when using a rotary fan delivery system concerns adequately controlling the path of each signature as the signatures are transferred from a slow down device to the rotary fan delivery system. In such systems, signatures generally fall from the slow down device to the rotary fan device. Stated differently, the signatures may be unsupported or unguided during this transfer step. Unsupported signatures have a tendency to freely flap, fold over, tear or be damaged in other different ways, or have a tendency to move to the wrong destination. The greater the distance between a slow down device and a fan delivery system, the more likely an unsupported signature will be damaged as it enters or attempts to enter the fan delivery system thereby causing jams in the overall process resulting in down time and repair expenses. 
     Yet another problem of utilizing a delivery system concerns guiding the signatures from a slow down mechanism to a subsequent processing device. Often, when a signature travels through a processing system between two signature transport tapes, the signature may tend to cling to one or both of the two tapes during the transition stage, instead of continuing on in a straight or substantially straight path to subsequent processing equipment. When a signature improperly follows a tape path and travels to the wrong place in the processing system, a jam can occur which results in the shut down of the entire printing production system until the jam is cleared. 
     Still another problem of such a delivery system concerns correctly timing the transfer of the signatures from one step in the printing process, such as a slow down step, to a subsequent step, such as a fan delivery step. If a respective signature slot in a rotary fan delivery device is not properly aligned with a signature emerging from a slow down mechanism at the appropriate time, a signature will be directed at the fan delivery device in such a way that the signature will not properly enter the rotary fan device which may cause a jam in the overall operation. 
     Although the problems described above generally correlate to a processing system which employs a rotary fan delivery device, the same or similar problems can occur in other delivery systems which utilize slow down mechanisms followed by other known processing equipment. The present invention may be utilized in various delivery systems for decelerating signatures and transferring the signatures to further processing equipment such as, for example, shingling devices or stackers, known to those skilled in the art. 
     Accordingly, there is a need for a sheet processing system that is capable of operating at high speeds, e.g., speeds in excess of 2,500-3,000 fpm and above, and yet is also capable of providing signatures that are acceptable in quality. What is needed is a delivery system which reduces the speed of signatures traveling through the processing system while allowing for an increased overall operating speed of the sheet processing system. What is also needed is a sheet processing system which increases control over signatures during a decelerating process and during transport of the signatures to a subsequent processing step. 
     In accordance with one embodiment of the present invention, a sheet diverter receives a fast moving stream of regularly spaced apart signatures from a sheet processing system. The sheet diverter sends the signatures down one of a plurality of collation paths. A signature slow down mechanism is positioned within the collation path such that as a signature travels down the collation path, the signature slow down mechanism grabs a tail end of the signature to slow down the speed of the signature. A pair of rotating cam lobes lying in general face-to-face relation along the collation path effectively reach into the collation path at the appropriate moment to grab the trailing end of the signature therebetween. 
     In a preferred embodiment, a pair of opposed tapes circulating in separate endless loops through the slow down mechanism and confining a signature therebetween, deliver the signature to the slow down mechanism which comprises a pair of counter-rotating independently driven roller or cam assemblies. The slow down mechanism has a lineal speed that is less than the lineal speed of the signatures so as to reduce the speed of the signatures as they are grabbed by the slow down mechanism. 
     In accordance with another embodiment of the present invention, regularly spaced apart signatures traveling at an original speed along a travel path are alternately diverted into a selected one of a plurality of collation paths to create a larger space between successive signatures in the selected paths after which the signatures are decelerated prior to being transferred to a subsequent process. The signatures are decelerated such that the leading edge of a trailing signature traveling down a selected one of the paths of signatures does not contact the trailing edge of a leading signature traveling down the same path as the leading signature is slowed down and the trailing signature continues on toward the slow down device. 
     In accordance with yet another embodiment of the present invention, a signature slow down mechanism is provided to decelerate the speed of individual signatures traveling along a path on their way to a further processing step in an overall sheet handling system. The slow down mechanism is positioned at the end of a collation path and is designed to be positioned as close as possible to the next device in the sheet handling system so as to increase control over the signatures as the signatures are transferred from one piece of equipment to another. 
     In accordance with still another embodiment of the present invention, a signature slow down assembly is provided along a path in which signatures travel on their way to further processing equipment in an overall sheet handling system. The signature slow down mechanism is capable of being opened and closed with respect to the path of the traveling signatures in order to clear away jams which may occur in the sheet handling system prior to, in or near, the signature slow down assembly. In addition, for those types of products produced in a printing press system which do not require the use of a slow down mechanism or need the advantages provided thereby, the adjustable, movable slow down mechanism can be, in effect, disengaged by moving the slow down device away from the signature path. 
     In a preferred embodiment, the signature slow down mechanism is capable of further adjustment so as to increase or decrease the gripping force applied to a signature as the signature is slowed down by the slow down mechanism. 
     In accordance with another embodiment of the present invention, a method for transporting signatures traveling at an original speed along a travel path through a sheet processing system is provided. The signatures are delivered to a slow down mechanism in which the speed of the signatures is reduced. The signatures are then fed to a further processing step. The original speed and position of the signatures, the position and operation of the slow down mechanism and the position and operation of the further processing equipment are phased in relation to each other so as to prevent or minimize damage to the signatures and increase the overall operating speed of the processing system. 
     In a further embodiment of the present invention, a signature guiding device is positioned intermediate of a signature slow down mechanism and a further delivery device. The guiding device is designed to prevent a signature from traveling along a wrong path as the signature is transferred from one device to the next. Preferably, the guiding device comprises a stripping signature eject idler roller which effectively strips a signature from a group of belts traveling in an endless loop in a processing system allowing the signature to properly continue on to the next step. An air blowing system may be used in combination with the eject idler roller or alternatively, by itself, to expel air in an appropriate manner thereby assisting in the control over the signatures as the signatures move from one device to another. 
     Accordingly, it is a general feature of the present invention to provide an apparatus for receipt of signatures from a high speed printing press and for slowing down the signatures to decrease signature damage, reduce jams and increase the overall operating speed of a sheet processing system. 
     Another feature of the invention is to provide a signature delivery system which is useful for a wide range of paper types and products over a wide range of press speeds and which is also useful in combination with diverter systems and signature discharge systems without significant modification to those systems. 
     Yet another feature of the present invention is to provide an improved signature delivery system which is easy to operate, easy to service, economical to manufacture and is relatively simple to construct and assemble. 
     Still another feature of the present invention is to provide a sheet processing system which increases control over signatures as the signatures travel from one processing step to another thereby decreasing signature damage, jams in the operating equipment and increasing overall speed of a printing press operation. 
     A further feature of the present invention is to provide a slow down mechanism that provides consistent, substantially non-varying signature transfer timing to subsequent processing equipment in a sheet handling system such as, for example, a rotary fan delivery system. 
     Yet, a further feature of the present invention is to effectively transfer signatures from a slow down mechanism to subsequent equipment in a sheet processing system thereby achieving the advantages provided for herein. 
     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial schematic diagram of a pinless folder in which various features of the present invention may be employed. 
     FIG. 2 is a partial cross-sectional view taken generally along line II—II of FIG. 1 showing a signature delivery system according to the present invention with certain parts added and removed for clarity. 
     FIG. 3 is a perspective view showing in clearer detail a signature slow down mechanism of FIGS. 1-2. 
     FIG. 4 is another perspective view showing even more detail of another slow down mechanism similar to that shown in FIGS. 1-3. 
     FIG. 5 is an illustrative view of a signature traveling through a signature delivery system according to the present invention and moving on to further processing equipment such as a rotary fan delivery device. 
     FIG. 6 is a perspective view of certain components of a signature guide assembly shown in FIG.  5 . 
    
    
     Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of “consisting of” and variations thereof herein is meant to encompass only the items listed thereafter. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Illustrated in FIG. 1 of the drawings is a partial schematic diagram of a pinless folder which is a part of a high speed printing press (not shown). A typical folder includes a forming section, a driving section, a cutting section, a diverting section and a collating section. The invention described herein is primarily directed to apparatus and methods found near the end of a collating section and upstream of further processing equipment in an overall printing press operation. A description of a typical pinless folder is found in U.S. Pat. No. 4,729,282, assigned to Quad/Tech, Inc., of Pewaukee, Wis., and is hereby incorporated by reference. Shown in FIG. 1, among other things, is a delivery system  10  according to the present invention. 
     Once a sheet or web has been transformed into a plurality of individual signatures as described, for example, in the &#39;282 patent, successive signatures enter a diverter section  12  including a pair of oscillating diverter rolls  13  along a diverter path  14 . The signatures are led serially via opposed tapes or belts  16  and  18  to a diverter  20 . The diverter  20  alternately deflects successive signatures to a selected one of a plurality of collation paths  22  or  24 . The signatures enter an appropriate collating section  26  or  28  and are fed along one of the collation paths  22  or  24  to a destination such as a rotary fan delivery device  30  and subsequently to a conveyor (not shown), such as a shingling conveyor as is known in the art. Prior to reaching the rotary fan delivery device  30 , the signatures travel through the delivery system  10 . 
     The signatures are routed along the diverter path  14  and to a selected one of the collation paths  22  or  24  under the control of a signature controller means including a primary signature controller  32  and secondary signature controllers  34  and  36 . Preferably, the distance through the diverter section  12  between the primary signature controller  32  and respective secondary signature controllers  34  and  36  is less than the length of the signature to be diverted. In this way, the selected secondary signature controller  34  or  36  assumes control of the leading edge of a signature before the primary signature controller  32  releases control of the trailing edge of the same signature. 
     The primary  32  and secondary signature controllers  34  and  36  include one or both of opposed face-to-face belts or tapes  16  and  18  disposed over rollers in endless belt configurations. The primary signature controller  32  includes the first diverter belt  16  and the second diverter belt  18  which circulate in separate continuous loops in the directions shown by the arrows in FIG.  1  and are joined at a nip between a set of idler rollers  38  near the outfeed of a cutting section (not shown), as such is described in the &#39;282 patent. Drive rollers  40  and  42  drive the diverter belts  16  and  18  respectively about, among other certain components in the separate continuous loops, idler rollers  38 , a plurality of idler rollers  44 , trailing edge signature slow down mechanisms  46  of delivery systems  10 , and idler rollers  48  and  50 . The diverter belts  16  and  18  are also driven around guide idler rollers  52 . Both diverter belts  16  and  18  are driven by respective drive rollers  40  and  42  at the same speed, which typically is from 8% to 15% faster than the paper speed through the printing press. The faster speed of the belts  16  and  18  causes a gap to occur between successive signatures as the signatures flow serially down path  14  between the diverter belts  16  and  18 . Preferably, for a signature having a length of about 10.875 inches, the gap between successive signatures is approximately between about 1-2 inches. Preferably, signatures travel generally vertically downward through the diverter section  12  alternately along collation paths  22  or  24  so that the signatures are bent as little as possible to avoid certain damage to the signatures. Since the signatures are alternately deflected and routed to one of a plurality of collation paths, the gap between successive signatures traveling down each collation path increases by at least the amount of the length of the signatures, typically, 10.875 inches. Therefore, the total gap between signatures traveling down a collation path includes the original gap length between successive signatures of about 1-2 inches, plus the length of a signature which is diverted to another collation path, plus the original gap length between what was originally successive signatures of about 1-2 inches. As will be further explained below, the gap between successive signatures in the collation paths, is one aspect of the present invention which assists in the operation of a slow down device according to that described herein. 
     The primary signature controller  32  includes a soft nip  54  defined by an idler roller  56  and an abaxially disposed idler roller  58 . The rollers  56  and  58  cause pressure between diverter belts  16  and  18  as these belts follow the diverter path  14  through the soft nip  54 . The soft nip  54  compressively captures and positively transports a signature that passes therethrough. Located upstream of the primary signature controller  32  is an idler roll  60  which also helps direct the signatures through the diverter section  12 . 
     The secondary signature controllers  34  and  36  include a first collator belt or tape  62  and a second collator belt or tape  64 , respectively, which both circulate in separate continuous loops in the directions shown by the arrows in FIG.  1 . The opposed collator belts  62  and  64  respectively share common paths with the diverter belts  16  and  18  along the collation paths  22  and  24 , beginning downstream of the diverter  20 . In particular, collator belt  62  is transported around idler rollers  52  and  66 , roll  68  of the respective trailing edge signature slow down mechanism  46 , idler roller  70 , drive roll  72  and idler roll  74 . Collator belt  64  is transported around idler roller  52 , snubber roller  76  of the respective trailing edge signature slow down mechanism  46 , idler rollers  78 ,  80  and  82 , drive roll  84 , and idler roll  86 . Idler rollers  88  and  90  also define the paths of the collator belts  62  and  64 . Rolls  70  and  82  are belt take-up rolls and are operable to adjust the tension in each belt loop of belts  62  and  64 . Rolls  72  and  84  drive belts  62  and  64 , respectively, around their continuous loops. The tension of diverter belts  16  and  18  can also be adjusted with belt take-up rollers A and B, which are connected via a pivotable lever arm to an air actuator that applies adjustable pressure to the belts  16  and  18  as illustrated. Since the tension in all four belts can be adjusted, adjustable pressure between opposed belts results to positively hold and transport signatures at tape speeds. Belts  16  and  18  are driven at the same speed as belts  62  and  64  through the use of timing belts and timing pulleys (not shown), such timing belts and timing pulleys generally known to those skilled in the art. The diameter of drive rolls  40  and  42  for the diverter belts  16  and  18  and the diameter of drive rolls  72  and  84  for the collator tapes  62  and  64  can be the same diameter so that the belts  16  and  18  and tapes  62  and  64  move at the same speed as the respective drive rolls rotate at the same rpm. However, it has been discovered that over the common paths traveled by belts  16  and  18  and tapes  62  and  64 , respectively, as a result of the different paths traveled by the belts and tapes, the wrap angles around the idlers in the noted paths, the tension applied to the belts and tapes, the tendency for the belts and tapes to stretch and/or creep, it has been determined that over the common paths traveled by belts  16  and  18  and tapes  62  and  64 , the belts and tapes travel different distances for the same degree of rotation of the respective drive rolls. Therefore, preferably, in order to account for the difference in distance traveled by the diverter belts  16  and  18  and collator belts  62  and  64 , the drive rollers  72  and  84  are made larger in diameter than drive rollers  40  and  42 . 
     The secondary signature controller  34  includes a soft nip  92  defined by idler roller  74  operating with the abaxially disposed idler roller  94 , the diverter belt  16  and the collator belt  62 . Similarly, the secondary signature controller  36  includes a soft nip  96  defined by idler roller  86  operating with the abaxially disposed idler roller  98 , the diverter belt  18  and the collator belt  64 . 
     Preferably, in a folder such as that shown in FIG. 1, it is contemplated that four signature delivery systems, two in front and two in back, will be used. FIG. 1 shows a front left-hand signature delivery system  10  and a front right-hand signature delivery system  10 . Not shown are the back left-hand and back right-hand signature delivery systems which lie generally adjacent to or directly behind the respective front signature delivery systems as such are arranged in the folder. Certain elements of the front left-hand signature delivery system are shown in FIG.  2  and an adjacent back left-hand signature delivery system is shown cut away. As illustrated in FIG. 1, it is contemplated that individual signatures are fed to a rotary fan delivery device  30  such as a rotary fan. Generally, there are the same number of fan devices as there are signature slow down devices. Other processing equipment can be used in place of the rotary fan delivery system in accordance with the principles of the subject invention. Each slow down mechanism  46  of a respective delivery system  10  is driven by its own individual motor whose timing phase relationship to signature arrival can be advanced or retarded as the situation requires, the details of which will be explained below. When utilized, each rotary fan is mounted on a shaft which is also driven by individual motors whose timing can be advanced or retarded so that the rotary fan pockets can be properly positioned in time relative to each signature slow down mechanism and the fan pocket injected signature. The slow down mechanism described herein slows down the original speed of the signatures before the signatures reach further processing equipment such as the rotary fan device. 
     The front left-hand signature slow down mechanism  46  shown in FIG. 1 is basically the same as the front right-hand signature slow down mechanism  46  shown in FIG.  1  and works in similar fashion except that the front right-hand signature slow down mechanism is located vertically above the front left-hand signature slow down mechanism because of the difference in the location of the two rotating fan buckets  30 . The two fan buckets  30  are spaced horizontally apart and at different heights because a pair of shingle conveyors (not shown) remove the product on the right-hand side of the machine and are placed one over the top of the other, as generally understood by those skilled in the art. 
     The other signature slow down mechanisms are, for all practical purposes, the same as the front left-hand signature slow down mechanism except for different mounting assemblies used to attach the signature delivery systems and components thereof to the proper framework in the folder. As such, only the front left-hand signature slow down mechanism will be explained in reference to most of the figures. The back left-hand signature slow down mechanism is shown in FIG. 4 to provide a different perspective in terms of the present invention. 
     Considering again FIG. 1, signatures traveling down the collation path  22  downstream of the diverter  20  are held between opposed belts  16  and  62  which firmly hold the signatures and positively transport the signatures on through the folder. The signatures approach idler roll  66  which generally represents the beginning of the signature delivery system  10 . Belts  16  and  62  start to diverge in linear fashion as they continue through the signature delivery system  10  (see FIG.  5 ). In other words, downstream of idler roll  66 , the belts  16  and  62  effectively let go of the signatures so that the signature slow down mechanism  46  can reduce the speed of the signatures as will be more fully explained below. 
     The signature delivery system  10 , according to the present invention, illustratively shown in FIG. 1, and more completely shown in FIG. 2, includes one or more of the following components: a lead-in idler roller  66 , a signature slow down mechanism  46  which includes a main roller assembly  100  and a snubber cam assembly  102 , a pivot shaft assembly  104 , an air cylinder assembly  106 , a signature guide assembly  108  and a drive system  110 . 
     With reference to FIG. 2, the main roller assembly  100  includes a housing  112  having a flange  113  which mounts to a machine side framework  114  with bolts  116 . A shaft  118  extends through the housing  112  and is supported by at least one bearing  120  which is supported by the housing  112 . Pulley  122  is attached to one end of the shaft  118  which enables shaft  118  to rotate by virtue of connection with the drive system  110  fully described below. Spaced apart main roller assembly cam members  124  are fixedly attached to shaft  118  with a key  126  (FIG. 5) and set screw  128 . Each main roller assembly cam member  124  includes an outwardly protruding cam-shaped lobe  130  (FIG.  5 ), the function of which will be made clear below. Spaced between each main roller assembly cam member  124  is a respective tape or belt idler roller  132  each of which rotates on respective bearings  134  which are secured to shaft  118 . A set collar (not shown) may cap the other end of shaft  118  in order to secure cam members  124  and tape rollers  132  in place. A standard nut and thread combination (not shown) could also be used to cap the other end of shaft  118  to secure the proper components in place. 
     With continued reference to FIG. 2, the snubber cam assembly  102  includes a shaft  138  upon which are mounted spaced apart snubber cam assembly cam members  140  which are preferably composed of two halves  142  and  144  (FIG.  5 ). The two halves  142  and  144  are held together with screws  146  and fixed to shaft  138  via keys  148  (FIG.  5 ). Snubber cam members  140  include outwardly protruding cam-shaped lobes  150  (FIG.  5 ). According to the present invention, snubber cam members  140  cooperate with main roller cam members  124  to slow down signatures traveling therebetween, as will be further explained herein. The lobes  150  of snubber cam members  140  are preferably made of steel covered with a layer of hard rubber that is molded to the steel. Snubber cam members  140  are made of a split construction (FIG. 5) so that they can be easily removed or added to shaft  138  without much other assembly or disassembly required. If a snubber cam member  140  wears out due to use, it can be easily replaced with a new snubber cam member. Also, snubber cam members  140 , because of their split construction, can easily be moved to different spots on the shaft  138  as desired. For example, depending on the number of desired snubber cam members  140 , the snubber cam members  140  can easily be relocated to proper positions along shaft  138 . Main roller assembly cam members  124  are preferably of a single construction and made from steel, but if desired, could also be of a split construction and incorporate rubber covered steel lobes, similar to snubber cam members  140 . The snubber shaft  138  is supported by a pair of bearings  152  and  154  at opposite ends thereof and which are mounted in respective swing arms  156  and  158 . Timing pulley  160  is attached to one end of the snubber shaft  138 . Timing pulley  160  enables shaft  138  to rotate as a result of connection with a belt such as a timing belt  162  which is a part of drive system  110  more fully described below. It should be noted that because of the out-of-balance forces caused by the cam-shaped lobes  130  of the main roller assembly  100  and the cam-shaped lobes  150  of the snubber cam assembly  102 , the assemblies  100  and  102  are dynamically balanced to allow for high speed rotation of the components so as to prevent damage to the assemblies  100  and  102  due to the rotational forces. Specifically, the forces generated by high speed rotation are counterbalanced in order to prevent damage to the bearings  120 ,  152  and  154  and reduce vibration which would occur if the assembly was left in an out-of-balance condition caused by the respective cam-shaped lobes  130  and  150 . 
     Still referring to FIG. 2, pivot shaft assembly  104  is coupled to snubber cam assembly  102 . Housing  164  having a flange  165  mounts to main machine wall  114  with screws  166  from the outside of the wall  114  as shown. The housing  164  and related parts are slipped through a bore in main machine frame  114  from the outside because assembly from the inside or other direction would be practically impossible because of the opposed components from the back side left-hand signature slow down device as shown. The housing  164  supports at least one bearing  166  which supports shaft  168 . Pulley  170  attaches to one end of pivot assembly shaft  168  and timing pulley  172  attaches to the other end of pivot assembly shaft  168 . Pulley  170  enables shaft  168  to rotate as a result of being connected to drive system  110 , as will be described directly below. Swing arms  156  and  158  house bearings  174  and  176 , respectively, which in turn support pivot assembly shaft  168 . The bearings  174  and  176  allow pivot assembly shaft  168  to rotate while swing arms  156  and  158  remain stationary. 
     It should be noted that the bearings described above may be axially fixed in or on the relevant components in any number at ways known to those skilled in the art, such as, for example, with retaining rings or shoulders. 
     Now, with reference to FIG. 3 in conjunction with FIG. 2, drive system  110  will be explained. Motor  178  includes a pulley  180  mounted to a motor output shaft  182 . A belt such as a timing belt  184  is properly wrapped around the pulley  180  attached to motor  178 , the pivot shaft assembly pulley  170  and main roller assembly pulley  122  so as to enable pivot assembly shaft  168  and main roller assembly shaft  118  to be driven in the directions shown by the arrows in FIG.  3 . Any slack in timing belt  184  may be removed with an internal belt take-up movable assembly idler  186 . Timing belt  162  is also properly wrapped around pivot shaft assembly timing pulley  172  and snubber cam assembly timing pulley  160 . Any slack in timing belt  162  may be removed with an external belt take-up assembly idler  188 . Preferably, pivot assembly shaft  168  turns at the same rotational speed (rpm) as the snubber cam assembly shaft  138  because the two are coupled together through timing belt  162  and through identically sized timing pulleys  160  and  172 . Also, preferably, pulleys  170  and  122  are identically sized so that pivot assembly shaft  168  and main roller assembly shaft  118  also turn at the same rotational speed (rpm). The drive system  110  is configured such that snubber cam assembly shaft  138  and main roller assembly shaft  118  turn in opposite directions as shown so that respective cam members  140  and  124  move in the direction of signature travel. Thus, the drive system  110  comprises a timing belt and timing pulley combination. The various pulleys may be provided with any number of teeth combinations to achieve the results described herein as can be appreciated by those skilled in the art. In a preferred embodiment, pulley  180  has 25 teeth and pulleys  170  and  122  have 40 teeth. Such an arrangement increases motor torque as applied to shafts  168 ,  138  and  118 . In this way, more motor torque will be applied where it is needed, namely, to the shafts  138  and  118  which include respective cam lobes  150  and  130 . 
     As shown in FIG. 4, the diverter belt  16  and collator belt  62  shown in FIG. 1 are part of separate groups of belts. Shown are seven diverter belts  16  and seven collator belts  62 . The collator belts  62  operatively engage with respective tape rollers  132  of main roller assembly  100  (see FIG.  3 ). Since the tape rollers  132  attach to bearings  134  (FIG.  2 ), the belts  62  cause the tape rollers  132  to freely rotate about main roller assembly shaft  118  irrespective of the rotation of shaft  118 . The main roller assembly cam members  124  keyed to shaft  118  are designed to rotate at a slower speed than tape rollers  132  as a result of shaft  118  being connected to drive system  110 . The diverter belts  16  travel between snubber cam assembly cam members  140  which are provided with sufficient clearance therebetween so that the belts  16  do not detrimentally contact the sides of the respective snubber cam members  140 . There are eight main roller assembly cam members  124 , seven main roller assembly tape rollers  132  and eight snubber cam assembly cam members  140  shown in FIG.  2 . Preferably, in order to properly support the signatures between the appropriate belts and tapes, seven belts and tapes are provided. For every belt or tape which travels around main roller assembly  100 , there is provided a respective main roller assembly tape roller  132 . For every tape roller  132 , there is preferably provided an adjacent cam member  124 . However, it is possible to use fewer snubber cam members  140  than there are main roller assembly cam members  124  (see FIG. 4 showing, for example, only five snubber cam members  140 ). The snubber cam members  140  can be appropriately positioned along shaft  138  between the respective tapes as previously described. It should be noted that with reference to FIG. 1, depending on the position of a slow down mechanism in a folder such as, for example, a front right-hand located signature slow down mechanism, the collator belts may travel around the snubber cam assembly and the diverter belts may travel around the main roller assembly. 
     FIG. 5 provides a clearer picture of a signature  190  being slowed down by a signature slow down mechanism  46 . The signature which is approximately 11 inches long travels through the main roller assembly  100  and snubber cam assembly  102  unimpeded until the last three inches or so of the signature. At that point, snubber cam-shaped lobes  150  of snubber cam members  140  reach out from between the diverter belts  16  and the main roller assembly cam-shaped lobes  130  of cam members  124  reach out from between the collator belts  62  in order to effectively grab the trailing end of the signature  190  to slow the speed of the signature  190  down. Since the cam-shaped lobes  150  and  130  of respective cam members  140  and  124  move at a slower lineal speed than the signature  190  and belts  16  and  62 , the speed of the signature  190 , having been effectively released by diverging belts  16  and  62  prior to reaching the signature slow down device  46 , is slowed as the slower rotating cam members  124  and  140  effectively grab the trailing edge of the signatures  190  with respective cam-shaped lobes  130  and  150 . 
     Preferably, the signature slow down mechanism  46  according to the present invention, is designed in such a way that for every signature delivered from a printing press which travels past the diverter  20  and down the left-hand collation path  22 , the cam-shaped lobes  130  and  150  of main roller assembly  100  and snubber cam assembly  102 , respectively, turn exactly once to slow down that particular signature by the right amount. As should be clear, the lineal speed of the cam-shaped lobes  130  and  150  of assemblies  100  and  102  is designed to be slower than the speed of the signatures and the speed of the tapes  16  and  62 . The signature slow down mechanism  46  is designed so that it is in synch with the printing press and timed properly to the printing press and how fast the signatures are being made at the printing press. Shafts  118 ,  138  and  168  turn at the proper rotational speeds so that the cam-shaped lobes  130  and  150  rotate at the proper speed by selecting the proper pulley diameters for  122 ,  160  and  170  and  172 , and the cam-shaped lobes  130  and  150  are made of the proper outside diameter so that the cam-shaped lobes move at the proper slow down signature speed. For every two signatures that are printed at the printing press, one goes down the left-hand side of the diverter  20  and the other one goes down the right-hand side of the diverter  20  and each signature slow down mechanism slows down the respective signature that travels to it. 
     Taking into account a number of variables, the diameters of cam members  124  and  140  can be determined for a given slow down mechanism. For a tapes speed gain factor of 13%, a signature having a length of 10.875 inches and a signature slow down factor of 30%, the diameters of cam members  124  and  140  should be about 5.5 inches. In a preferred embodiment, the speed of the cam-lobes is designed to be 20%-40% slower than the signature speed which is generally the same as the speed of the belts confining the signature therebetween. 
     It should be noted here that, with reference to FIGS. 3 and 5, initially, the cam-shaped lobes  130  and  150  can be properly aligned generally face-to-face along the signature path by removing timing belt  184  from pulleys  170  and  122 . Pivot assembly shaft  168  can then be rotated until cam lobes  150  are positioned opposite cam lobes  130 . After which, timing belt  184  is repositioned around pulleys  170  and  122 . Once the cam lobes  130  and  150  are properly aligned, the position of the lobes  130  and  150  with respect to signature arrival can be adjusted through the use of motor  178  and the drive system  110 . 
     Returning once again to FIG.  2  and in conjunction with the back left-hand signature slow down mechanism shown in FIG. 4, air cylinder assembly  106  is described. One end of each air cylinder  192  connects to respective swing arms  156  and  158  through a standard screw, nut and clevis combination  194 . A tie bar  196  mounts to main machine wall  114  with screws  198 . Although not shown, the other end of tie bar  196  attaches to another machine wall opposite wall  114 . A pair of stationary brackets  200  mount to tie bar  196 . The stationary brackets  200  and air cylinders  192  are provided with bores so that a separate pivot pin  202  can extend through the brackets  200  and the cylinders  192  in order to attach the other ends of the air cylinders to the stationary brackets  200 . An internally threaded adjustable knob  204  is positioned on each of the respective rear threaded rod ends of the double rod end air cylinders  192 . 
     The air cylinders  192  are provided so that the snubber cam assembly  102  can be opened or closed as needed. Engaging air cylinders  192  in one direction or the other causes swing arms  156  and  158  to rotate the snubber cam assembly  102  into or away from main roller assembly  100  (see FIG.  4 ). For example, in the event of a jam, at or near the signature slow down mechanism  46 , the snubber cam assembly  102  can be opened via electronic controls so that the jam can be cleared away. As another example, it may be desirable to run a printing press system in which a slow down device is not needed for the particular product being processed. In such a case, the slow down mechanism can be moved away from the path of the signatures so as not to interfere with the speed of the signatures. 
     The air cylinders  192  are provided for another reason in addition to that noted above. The internally threaded knobs  204 , which act much like a standard nut, control and limit the amount of extended (forward) stroke of the respective air cylinders  192 . Since the air cylinders  192  are connected to respective swing arms  156  and  158  which are connected to snubber cam assembly  102 , by turning knobs  204 , a fine adjustment can be made to the gap between the two opposite facing cam-shaped lobes  130  and  150  (see FIG.  5 ). The adjustment of the nut-like knobs  204  can be locked with a clamping screw lever mounted on the knobs  204  (not shown) so as to lock the air cylinders in place. Adjusting the gap between cam-shaped lobes  130  and  150  ensures that signatures traveling therebetween are not squeezed too hard which could cause damage or mar the folded signatures. A certain amount of signature squeeze is necessary, however, so that the speed of the signatures is adequately and accurately slowed down as planned, keeping in mind that excessive squeezing is to be avoided to prevent damage to the signatures. 
     Referring back to FIG. 2, a further aspect of the signature delivery system  10  is described. Shown is part of a signature guide assembly  108 . FIGS. 5 and 6, show in further detail, other parts of a signature guide assembly  108 . Shown in FIG. 2, housing  206  having a flange  207  mounts to the machine wall  114  with screws  208 . Housing  206  holds at least one bearing  210  which supports an idler shaft  212 . Idler  212  is shown in FIG. 1 downstream of the snubber roll  76  of slow down mechanism  46  in the path of the belts  16 . Idler  212  is a grooved roll referred to as a signature eject roller. Between each groove  214  is a respective raised step  216 . Belts  16  travel within respective grooves  214 . The grooves  214  are wider than the width of the belts  216 . Preferably, each groove  214  is slightly crowned so that as a belt  16  travels within a respective groove  214 , the belt does not substantially wander from side to side between respective raised surfaces  216 . The function of the crown is to keep the belts  16  running in the middle of the grooves  214  as much as possible. 
     As shown in FIG. 1, preferably a second idler roll  218  is provided to the left and parallel to eject roller  212  also within the path of belts  16 . Idler  218  can be a grooved roll like eject roller  212  (see FIG. 4) but can also be a smooth non-grooved idler roll. Idler  218  is provided to share the belt load with idler  212 , the load being generated by belt length variation, belt tension and belt wrap angle of belts  16 . 
     Shown also in FIG. 2, is a second signature eject roller  220 . The eject roller  220  is shown in FIG. 1 downstream of main roll  68  of slow down mechanism  46  in the path of the collator belts  62 . Eject idler roller  220  is also a grooved roll like eject roller  212 . Preferably, so that the eject rollers  212  and  220  can be positioned as close as possible to the fan delivery device  30 , the diameter of eject roller  220  is smaller than the diameter of eject roller  212 . As the signatures travel through the slow down mechanism  46  on their way to the fan delivery device  30 , it is desirable to support the signatures as much as possible. By positioning the signature eject rollers  212  and  220  as close as possible to the outside diameter of the fan delivery device  30 , there is less chance that the signatures will be damaged as they enter the fan delivery device thereby reducing the likelihood of jams occurring in this area. 
     FIG. 6 shows the signature eject roller  220  in the greatest detail. Brackets  222  and  224  are oppositely positioned around driven shaft  118  of main roller assembly  100 . The brackets house bearings  226  so that shaft  118  is able to rotate while the brackets  222  and  224  remain stationary. The mounting brackets  222  and  224  are connected at one end by tie bar  228  which is attached to the brackets by screws  230 . The brackets  222  and  224  are prevented from rotation by fixedly tieing bracket  222  to housing  112  of main roller assembly  100  with a dowel pin or similar means not shown. Mounted to the other end of brackets  222  and  224  is the signature eject roller  220  (see also FIG.  5 ). Eject roller  220  includes grooves  229  and raised steps  231  which are similar to grooves  214  and steps  216  of eject roller  212 . Eject roller  220  can be positionally adjusted with respect to collator belts  62  depending on where the brackets  222  and  224  are fixed relative to housing  112 . Although not shown, a stationary shaft is positioned through the eject roller  220 . The shaft is attached to brackets  222  and  224  with screws or the like. The eject roller  220  houses a pair of bearings which allows the idler eject roller  220  to rotate on the stationary shaft. One or both of the brackets  222  and  224  contain a slot near where the stationary shaft mounts to the brackets  222  and  224 . In this way, when the bearings housed in the eject roller  220  need to be replaced, the eject roller  220  can simply be removed from the brackets  222  and  224  and then easily returned thereto once the bearings have been replaced. 
     As the signatures travel down through a signature slow down mechanism, there is a natural tendency for the signature to want to cling to the transport belts or tapes and follow the belts or tapes rather than continue on in a straight path to further processing equipment which may lead to jams in the overall system. The signature eject rollers  212  and  220  are provided to prevent this scenario from happening. With reference to FIGS. 2,  5  and  6 , the diverter belts  16  travel in the grooves  214  of eject roller  212  and the collator belts  62  travel in the grooves  229  of eject roller  220 . The respective raised steps  216  and  231  are sufficiently extended to reach beyond the respective belts  16  or tapes  62 . If a signature attempts to follow belts  16  and/or tapes  62  around the bottom of eject rollers  212  and/or  220 , the raised step  216  and/or  231  will contact a respective side of the signature thereby forcing the signature from the respective belt or tape. In this way, the signatures are prevented from incorrectly following the belts  16  or tapes  62  and the signatures are sent on a substantially straight course into further processing equipment such as a rotary fan device  30 . 
     The signature eject rollers  212  and  220  can be referred to as rotary signature strippers. The eject rollers rotate at the speed of the belts or tapes in contact therewith. An advantage of the rotary signature stripper is that the signature eject rollers  212  and  220  are moving as they effectively strip the signature thereby causing less damage to the signatures than what a stationary stripper may cause. 
     Also, shown in FIGS. 5 and 6, is an air blowing device  232  which is another component of the overall signature guide assembly  108 . The air blowing device  232  and signature eject rollers  212  and  220  may be used in conjunction with or independent of each other. The air device  232  is positioned downstream of eject roller  220 . The air blowing device  232  is preferably composed of two round tubes  234  and  236  but may be a single tube fixedly attached to brackets  222  and  224 . One tube  234  is shown in FIG.  6 . As shown in FIG. 5, the air device  232  is positioned adjacent the signature path of the signatures. The air tubes  234  and  236  preferably have a row of evenly spaced holes through which air can be blown through. The air to each tube is independently provided from a source of pressurized air, not shown, attached to one or more nipples  238 . The amount of air flow and how the source of pressurized air is attached to the air device  232  is not significant in terms of the present invention. As shown in FIG. 5, the top tube  234  is positioned such that air can be blown toward the body of the signatures and towards the open side of the signatures traveling past the air device  232  from the signature slow down mechanism. The bottom tube  236  is positioned such that air can be blown generally parallel to the direction the signatures travel past the air device  232 . The air device assists in guiding the signatures from the slow down mechanism  46  to the next step in the sheet processing system such as a fan delivery device  30 . The air device also prevents a folded signature from opening at its open end as the signature is transferred from the slow down device to the downstream equipment. If the signature were to open, it could cause a jam of the overall system. 
     Another component of the overall system described thus far and which may also be a part of the signature delivery system  10  is a diverging belt or tape adjustment roller  240 , shown only in FIG.  5 . The roller  240  is mounted to machine wall  114  such that the roller  240  is adjustable in a horizontal direction generally transverse to the signatures and belts travel path as shown by the double arrow. The adjustable roll  240  is preferably provided to control and modify when the belts  16  and  62  will begin diverging from a point downstream of the slow down device lead-in roll  66 . In addition, adjustable roll  240  can be used to manipulate the belts  16  and/or tapes  62  in order to assist in preventing a folded signature from wanting to cock or go crooked as it travels downward toward opposed cam lobes  130  and  150  of the signature slow down mechanism  46 . As a folded signature travels down the collation path  22  past the lead-in idler roll  66 , the signature has a tendency to want to cock or become crooked between the belt  16  and tape  62 . The folded signature is not as thick on its open side as it is on the folded side. The open side of the signature tends to want to fall down quicker than the folded side as the signature travels to the slow down device  46 . The ends of roller  240  can be individually adjusted generally transverse to the path of the signatures and belts. As a result, by skewing roller  240 , the belt  16  and tape  62  can be caused to grip the open side of the signature more firmly thereby preventing the open side of the signature from falling ahead of the folded side of the signature. Roller  240  could also be designed to be smaller in length than, for example, lead-in roller  66 , and positioned in the delivery system so as to only effect those portions of belts  16  and/or  62  which transport the open side of the signature. 
     As is readily apparent in FIG. 2, the main roller assembly  100 , the snubber cam assembly  102 , the pivot shaft assembly  104  and the signature guide assembly  108  are cantilever mounted to the framework  114  of the folder. The purpose of the cantilever design is so that all of the belts and tapes used in the delivery system  10  are easy to install, remove and replace. In other words, since a folder according to the present invention may include four delivery systems as explained above, the noted assemblies are designed in such a way that there is a break in the middle of the machine (FIG. 2) so that belts or tapes can be easily inserted, removed or replaced between the front and back delivery systems as needed. 
     In another embodiment of the present invention, sensors (not shown) are provided upstream of the slowdown mechanism  46  and preferably near idler lead-in roll  66  to sense the location of the leading edge of the signatures as the signatures are delivered to the slow down device  46 . The sensors may be any type of sensor known to those skilled in the art designed to indicate the position of a moving article such as, for example, a through-beam sensor or an infra-red sensor. Signals from the sensors are delivered to the motor  178  to control the operation of the motor  178  which controls the drive system  110 . Signals from the sensors can be provided to the motor  178  such that the cam members  124  of the main roller assembly  100  and the cam members  140  of the snubber cam assembly  102  can be properly positioned such that the respective cam lobes  130  and  150  grab the trailing end of each signature traveling through the slow down mechanism  46 . If the cam-lobes  130  and  150  do not properly grab the trailing end of the signatures, the motor  178  can be advanced or retarded so as to correct the position of the cam lobes  130  and  150 . 
     The same sensors can also be used to send signals to the motors (not shown) driving the fan delivery system  30  such that the appropriate slot in the fan delivery system is positioned to receive the signatures as the signatures are delivered to the fan delivery system. 
     The motors of the slow down devices and the motors of the fan delivery devices can be phased so as to provide for optimum delivery of the signatures through the slow down devices and to the fan delivery devices. 
     In general, with reference to FIG. 1, considering what is shown in FIG. 5, signatures travel in tandem down the diverter path  14 . All of the signatures are moving at approximately the same speed and they are following each other one behind the other with a gap of a predetermined distance between them. As the signatures approach the diverter  20 , one signature will go down one collation path  22  and the next signature will go down the other collation path  24  and so on. Before being diverted, the signatures have a space between them equal to about 1-2 inches. As the signatures are diverted, the space between each signature grows by the length of one signature plus another 1-2 inches because every other signature is directed down a separate collation path. Downstream of diverter  20  is a signature slow down mechanism  46 . A front leading signature approaches the slow down mechanism  46 . A second following signature that has not yet reached the slow down mechanism  46  is traveling still at the original speed. Since the first signature is slowed down by the slow down mechanism  46  as it travels through the slow down mechanism  46 , the gap between the two signatures is shrinking at a very fast rate and there is a possibility of a collision between the signatures if the gap becomes too small. In other words, if the front signature is slowed down too much, the signature that is following it could crash into it. Because of the diverter  20 , which sends every other signature to a different location, the space between the signature becomes larger by one signature length and one gap space and therefore you can slow down the front signature more than you could without the diverter  20 . 
     The foregoing description of the present invention has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention in the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings in skill or knowledge of the relevant art, are within the scope of the present invention. The embodiments described herein are further intended to explain the best modes known for practicing the invention and to enable others skilled in the art to utilize the invention as such, or other embodiments and with various modifications required by the particular applications or uses of the present invention. It is intended that the appended claims are to be construed to include alternative embodiments to the extent permitted by the prior art. 
     Various features of the invention are set forth in the following claims.