Abstract:
A transport assembly with a driven split rollers and split nip gap includes a support and a first drive roller that is rotatably mounted to the support about a first drive roller axis. The first drive roller is driven by gears, belts or the like for rotating the first drive roller about its axis. A number of nip rollers are adjustably mounted to the support and positioned in spaced apart relation and adjacent to the first drive roller with the first drive roller being in frictional communication with each nip roller with the nip rollers being driven by the first drive roller. A second drive roller is rotatably mounted to the support and is positioned a distance from the each of the first nip rollers to define a split nip gap for receiving and transporting a web therethrough. The nip gap distance between each of the nip rollers is individually adjustable while being directly driven by the first drive roller.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority from prior U.S. Provisional Application Ser. No. 60/577,718 filed on Jun. 7, 2004. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates generally to transport assemblies, namely, assemblies for transporting paper and other web media. More specifically, the present invention relates to a new and novel transport assembly that includes split nip rollers that are driven to provide a split nip gap with adjustable gap across the width of the web.  
         [0003]     This invention relates to the control of a web, such as paper other web media, through a folding machine or printing apparatus. It should be understood that the present invention relates to transport of any type of media but paper, in particular, will be discussed in detail. This in no way limits the scope of the present invention to paper transport and it is intended that the present invention can be employed for transport of any type of web.  
         [0004]     In prior paper transport assemblies, it is common to provide a drive roller and associated nip or pinch rollers, which are spring biased against the drive roller, for effecting a resultant frictional force for transporting a sheet of paper or paper web that is fed between the drive roller and the nip or pinch rollers. Typically, the drive roller and the nip rollers span across the entire width of traveling paper web with a uniform nip gap thereacross because typically the paper traveling between the drive roller and the nip rollers is of equal thickness across its width.  
         [0005]     It is sometimes desirable for the thickness of a traveling web to be thicker at one point across the width of the web than at another point. For example, the web may have multiple layers, such as due to folding, at one running portion of the web. In such a folder, multiple webs may enter the machine to adjust the gaps between the driven rollers in the paper feed section of the machine. In the final stages of the paper feed, it is important to drive both sides of the nips for consistent feed of the web or webs to avoid undesirable skewing.  
         [0006]     The multiple webs may be distributed in one or more streams entering the folder. For example, there are double width folders where two streams of ribbons enter the folder side by side. In this case, the number of ribbons on each side will result in different thicknesses across the width of the web. Thus, the resultant nip gap is different at different locations across the width of the traveling web where the thickness of the web is different.  
         [0007]     In the prior art, there is difficulty in spacing the nip rollers to accommodate different thicknesses of the web, particularly where on only drive roller and only one nip roller is provided across the entire width of the traveling web. More specifically, rollers that span across the entire width of a web that has different thickness will wear unevenly causing the roller to fail more quickly. This can cause paper skewing resulting in jams and other problems.  
         [0008]     There have been attempts in the prior art to addresses the problem associated with accommodating webs that have different thicknesses across their width. For example, as shown in prior art  FIG. 1 , a web transport assembly  10  is provided with a frame  12  that carries a main drive roller  14  which is driven by belts  16 , or other structures, such as gears. The nip rollers  18  and  20  can be split into two groups so that respective nip gaps  22  and  24  associated with each of the sets of split nip rollers  18  and  20  can be independently adjusted to accommodate the thickness of the portion of the web traveling therethrough. As can be understood, nip rollers  18  must be adjusted to the same nip gap  22  and nip rollers  20  must be adjusted to the same nip gap  24 . Nip rollers  18  and  20  cannot be individually adjusted.  
         [0009]     For example, in the prior art  FIG. 1 , the main nip roller  14  is directly driven. On the opposing side of the web, nip rollers  18  and  20  are driven by belts  26  and  28  or meshed gears which can be driven off the belt  16  of the main nip roller  14 . However, this direct driving of nip rollers  18  and  20  limits the number of adjustable rollers to two because each one is driven by one side by belts  26  and  28 , which are in turn connected to the belt  16  attached to roller  14 . Thus, a third adjustable zone is not easily feasible because driving a shaft location in the middle of the assembly, from the outer two shafts, is not easily achievable because the lateral space taken by the bearing supports on the trolley shafts is considerable thereby resulting in dead space.  
         [0010]     Therefore, there is a need to provide more than two adjustable nip rollers to provide more than two adjustable nip gaps for accommodating a web with more than two thicknesses across its width.  
         [0011]     To further address the need for more than two adjustable nip gap zones across the width of the web, adjustable trolleys  52 , as shown in prior art  FIG. 2 , in a prior art assembly  50 . The trolleys  52  are provided on the opposing side of the web  54  from main driven roller  56 . Each individual trolley  52 , and roller  58  associated therewith, can be adjusted so the distance between each roller  58  and the main driven roller  56  can be specifically selected to accommodate the thickness of the paper web  54  traveling therethrough. However, the adjustable trolleys  52  of prior art  FIG. 2  are passive idlers that merely ride on the paper web  54  on the opposite side of the main driven roller  56 . Thus, prior art assembly  50  suffers from the disadvantage of having only one roller  56  on one side of the web  54  that is actively driven which reduces the amount of control over web transport.  
         [0012]     In view of the foregoing, the transport assemblies of the prior art suffer from various disadvantages that make them difficult and awkward to use with unexpected results. Therefore, there is a need for a transport assembly that can provide multiple nip rollers across the width of a traveling paper web. There is a further need for a transport assembly that provides multiple nip rollers that are each driven rollers rather than mere idling rollers. There is yet a further need in for a transport assembly that can provide more than two split nip rollers across the width of a web. There is a need for a transport assembly to provide a split nip rollers that can be individually adjusted to provide different nip gap across the width of a traveling web to accommodate different thicknesses thereof.  
       SUMMARY OF THE INVENTION  
       [0013]     The present invention preserves the advantages of prior art paper web transport assemblies. In addition, it provides new advantages not found in currently available assemblies and overcomes many disadvantages of such currently available assemblies.  
         [0014]     The invention is generally directed to a novel and unique paper web transport assembly that can accommodate a paper web with different thicknesses across the width of the traveling web.  
         [0015]     The present invention uniquely provides the capability of more than two individually adjustable trolley-mounted nip rollers that are also driven to provide better web control. A first driven roller is provided on one side of the paper web. Adjustable trolleys rollers are provided in contact with the opposing side of the web and are adjusted to provide the desired nip gap across the width of the web where each trolley can provide a different nip gap corresponding to a given nip gap zones. A second driven roller frictionally interfaces with the rollers of trolleys to drive them. The geometry and the positioning of the trolleys relative to driven roller enable roller to frictionally drive all of the trolleys even though they are positioned at different distances from the drive roller to provide different nip gaps. The ability to adjust the nip rollers and still be in frictional communication with the drive roller is well within the acceptable tolerance or error to maintain the needed friction to drive the individual nip rollers even though they are adjusted to different distances to providing different nip gaps in their respective nip gap zones.  
         [0016]     It is therefore an object of the present invention to provide a paper web transport assembly that is capable of providing more than two nip rollers across the width of a web.  
         [0017]     It is a further object of the invention to provide a paper web transport assembly where two or more nip rollers are each actively driven rather than passively as in the prior art.  
         [0018]     It is further an object of the present invention to provide a paper web transport assembly that can individually adjusted to provide different nip gaps to accommodate a traveling web with different thicknesses across its width.  
         [0019]     Another object of the present invention is to provide a paper web transport assembly that includes a nip roller drive assembly that can be easily modified to accommodate additional individually adjustable nip roller assemblies yet still be actively driven. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The novel features which are characteristic of the present invention are set forth in the appended claims. However, the invention&#39;s preferred embodiments, together with further objects and attendant advantages, will be best understood by reference to the following detailed description taken in connection with the accompanying drawings in which:  
         [0021]      FIG. 1  is a front elevational view of a prior art paper web transport assembly with two actively driven split nip roller sections;  
         [0022]      FIG. 2  is an elevational view of a prior art paper web transport assembly with multiple passively driven idling nip rollers;  
         [0023]      FIG. 3  is a perspective view of a paper web transport assembly of the present invention;  
         [0024]      FIG. 4  is a rear elevational view of the paper web transport assembly of  FIG. 3 ; and  
         [0025]      FIG. 5  is a cross-sectional view through the line  5 - 5  of  FIG. 4 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]     Referring first to  FIG. 3 , a perspective view of the paper web transport assembly  100  of the present invention is shown. A first drive roller  102  is provided on a first side of the traveling web  104  of paper. A number of nip rollers  106   a - d  on individual trolleys  108   a - d  (as seen in  FIG. 4 ) are provided on a second side of the web  104 . These nip rollers  106   a - d  are not merely idling rollers, as in the prior art, but are actively driven rollers. The active driving of the nip rollers  106   a - d  is carried out by the use of a drive roller, namely a second drive roller  110  that is positioned to be in frictional communication with each of the nip rollers  106   a - d . Thus, the second drive roller  110  causes the nip rollers  106   a - d  to actively rotate to assist in movement of the web  104  in conjunction with the first drive roller  102 .  
         [0027]     As can be seen in  FIG. 3 , the single second drive roller  110  can drive a larger number of nip rollers  106   a - d  across the width of the web  104  for added flexibility in web control. The nip rollers  106   a - d  are mounted on individual trolleys  108   a - d  so they can be easily spaced and adjusted as desired, as will be described in detail below. Most importantly, each nip roller  106   a - d  can be respectively independently adjusted to vary the nip gap  112   a - d  between it and the first drive roller  102  positioned on the opposite side of the web  104 . Thus, nip gap zones can be provided to accommodate web streams of differing thickness across the with of the web  104  which may be encountered by the assembly  100  due to folded portions of the web  104 , for example.  
         [0028]     Turning now to  FIG. 4 , a front elevational view of the paper web assembly  100  of the present invention is shown. The first drive  102  roller is rotatably mounted to a support structure  114 , such as a frame. The first drive roller  102  is rotatably driven preferably by belts  116 , but could also be driven by gears and other similar structures.  
         [0029]     The second drive roller  110  is also mounted to the support structure  114  and is rotatably driven by belts  118 , or the like. The belts  118  for the second drive roller  110  is preferably linked by pulleys  120  to the first drive roller  102  or it may be independently driven. The second drive roller  110  powers a number of nip rollers  106   a - d  across the width of the assembly  100 .  FIG. 4  shows four nip rollers  106   a - d  in spaced apart relation to one another, yet they are all actively driven by the aforesaid frictional communication with the second drive roller  100 . While four nip rollers  106   a - d  are illustrated, more or less than four nip rollers  106   a - d  can be employed and still be within the scope of the present invention.  
         [0030]     It can be seen in  FIG. 4  that the nip rollers  106   a - d  are each mounted on their own respective trolley structures  108   a - d  to enable individual adjustment of the location and respective nip gaps  112   a - d  created, as will be shown in further detail below in connection with  FIG. 5 . The nip gaps  112   a - d  can be individually set for each nip roller  106   a - d  to accommodate the thickness of the paper web  104  at that point across the width thereof. For example, a portion of the web, referenced as X in  FIG. 3  with thickness T as shown in  FIG. 4 , may be thicker because it includes a folded portion of the web  104  thereby necessitating a larger nip gap  112   a  to avoid paper jams or skewing. With the present invention, the rightmost nip roller  106   a  in  FIG. 4 , which corresponds to the leftmost nip roller  106   a  in FIG.  3 , can be adjusted to provided this needed nip gap  112   a  to accommodate the web  104  with a thickness T in region X. Other nip gaps  112   b - d  formed by other nip rollers  106   b - d  may be the same, greater than or less than the nip gap  112   a  formed by the nip roller  106   a  over region X of the web  104 . This ability of the present invention to provide multiple actively driven nip rollers  106   a - d  across the width of the web  104 , that can be individually adjusted, provides unprecedented control of the paper web  104  not found in prior art paper transport assemblies.  
         [0031]     Turning now to  FIG. 5 , a cross-sectional view through the line  5 - 5  of  FIG. 4  is shown.  FIG. 5  illustrates a preferred embodiment of the assembly  100  employed for individual adjustment of the nip rollers  106   a - d . As shown and described in  FIGS. 3 and 4 , the first drive roller  102  is provided on one side of the web  104  while a second drive roller  110  actively frictionally drives the nip roller  106   a . It can been by the marking in the center of the first drive roller  102  and the second drive roller  110  that they are each directly driven by belts, and the like. The nip roller, such as nip roller  106   a , frictionally slaves off of the second drive roller  110  so that it may be actively driven rather than merely idling off of the first drive roller  102  and the paper web  104 .  
         [0032]     Preferably, the second drive roller  110  is connected by a pivot mount  122  to a support structure, such as the frame  114  illustrated in  FIG. 4 . An adjustable linkage  124  is connected to the pivot mount  122  to vary the pivot angle of the pivot mount  122  to thereby position the first drive roller where desired. Similarly, the nip roller  106   a  is connected by a pivot mount  126  to a support structure, such as the frame  114  in  FIG. 4 . An adjustable linkage  128  is connected to the pivot mount  126  which is connected to the nip roller  106   a  to vary the pivot angle of the pivot mount  126  to thereby position the nip roller  106   a  where desired, namely, at a location from the first drive roller  102  to form a nip gap G of a desired distance to accommodate a web  104  having a thickness that is traveling therethrough. This configuration can be general referred to as the trolley  108   a . For example, the nip gap G in  FIG. 5  may be selected to be T to accommodate paper region X as shown in  FIG. 3 . The nip roller  106   a  and the second drive roller  110  are adjusted relative to each other to ensure that they frictionally engage each other so that the nip roller  106   a  is actively driven.  
         [0033]     The configuration shown in  FIG. 5  is present for each of the nip rollers  106   a - d  across the width of the assembly  100 . The geometry of this arrangement is such that each of the nip rollers  106   a - d  and their trolleys  108   a - d  can be adjusted to define a nip gap  112   a - d  with the first drive roller  102  with only a small “error” relative to the second drive roller  110 . Thus, the forces form the second drive roller  110  act against the nip rollers  106   a - d  to drive them with little or no effect on their respective nip gaps  112   a - d.    
         [0034]     More specifically, each of the nip rollers  106   a - d  across the width of the assembly are adjusted and set in place to provide the desired nip gap  112   a - d  with the first drive roller  102 . Thus, the nip rollers  106   a - d  may not be all co-axial with one another. The second drive roller  110  is then positioned to frictionally communicate with each of the nip rollers  106   a - d  even though they are not necessarily co-axially with one another. Thus, some of the rollers  106   a - d , for example those adjusted to provide a larger nip gap, will have a tighter frictional communication with the second drive roller  110  than those rollers adjusted to provide small nip gap. The resiliency of the rollers  106   a - d , which can be made of rubber, or the like, enables the aforesaid “error” in positioning of differently adjusted nip rollers to have no affect on the consistent friction driving of the nip rollers  106   a - d.    
         [0035]     It should be understood that the use of the adjustable pivot structure of  FIG. 5  is just one of many different structures that can employed to position the first drive roller  102 , the second drive roller  110  and the nip rollers  106   a - d  relative to each other to obtain the desired nip gap and web control.  
         [0036]     The assembly of the present invention can accommodate any type of rollers, support structures and adjustment configurations. The dimensions shown in the  FIGS. 3-5  of the present invention are shown by way of example and are not intended to limit the scope of the present invention. Also, the first drive roller  102 , the second drive roller  110  and the nip rollers  106   a - d  are shown to be of the same general configuration, namely, size in cross-section. For example, it is possible with the present invention to vary the size of the nip rollers  106   a - d  to achieve a different sized nip gap  112   a - d  when frictionally driven by the second drive roller  110 .  
         [0037]     In summary, a new and novel paper web transport assembly  100  is provides that includes more than two actively driven nip rollers, such as  106   a - d . Each of the nip rollers  106   a - d  can be adjusted to provide a desired nip gap between it and an opposing driven roller  102 . The nip gaps  112   a - d  can be adjusted and set across the width of the paper web  104  to accommodate different thicknesses of the paper web  104  to ensure smooth transport therethrough.  
         [0038]     It would be appreciated by those skilled in the art that various changes and modifications can be made to the illustrated embodiments without departing from the spirit of the present invention. All such modifications and changes are intended to be covered by the appended claims.