Transport assembly with driven split nip rollers

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

This application claims priority from prior U.S. Provisional Application Ser. No. 60/577,718 filed on Jun. 7, 2004.

BACKGROUND OF THE INVENTION

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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

The novel features which are characteristic of the present invention are set forth in the appended claims. However, the invention'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:

FIG. 1 is a front elevational view of a prior art paper web transport assembly with two actively driven split nip roller sections;

FIG. 2 is an elevational view of a prior art paper web transport assembly with multiple passively driven idling nip rollers;

FIG. 3 is a perspective view of a paper web transport assembly of the present invention;

FIG. 4 is a rear elevational view of the paper web transport assembly of FIG. 3; and

FIG. 5 is a cross-sectional view through the line 5-5 of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

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 106a-d on individual trolleys 108a-d (as seen in FIG. 4) are provided on a second side of the web 104. These nip rollers 106a-d are not merely idling rollers, as in the prior art, but are actively driven rollers. The active driving of the nip rollers 106a-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 106a-d. Thus, the second drive roller 110 causes the nip rollers 106a-d to actively rotate to assist in movement of the web 104 in conjunction with the first drive roller 102.

As can be seen in FIG. 3, the single second drive roller 110 can drive a larger number of nip rollers 106a-d across the width of the web 104 for added flexibility in web control. The nip rollers 106a-d are mounted on individual trolleys 108a-d so they can be easily spaced and adjusted as desired, as will be described in detail below. Most importantly, each nip roller 106a-d can be respectively independently adjusted to vary the nip gap 112a-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.

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.

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 106a-d across the width of the assembly 100. FIG. 4 shows four nip rollers 106a-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 106a-d are illustrated, more or less than four nip rollers 106a-d can be employed and still be within the scope of the present invention.

It can be seen in FIG. 4 that the nip rollers 106a-d are each mounted on their own respective trolley structures 108a-d to enable individual adjustment of the location and respective nip gaps 112a-d created, as will be shown in further detail below in connection with FIG. 5. The nip gaps 112a-d can be individually set for each nip roller 106a-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 112a to avoid paper jams or skewing. With the present invention, the rightmost nip roller 106a in FIG. 4, which corresponds to the leftmost nip roller 106a in FIG. 3, can be adjusted to provided this needed nip gap 112a to accommodate the web 104 with a thickness T in region X. Other nip gaps 112b-d formed by other nip rollers 106b-d may be the same, greater than or less than the nip gap 112a formed by the nip roller 106a over region X of the web 104. This ability of the present invention to provide multiple actively driven nip rollers 106a-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.

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 106a-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 106a. 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 106a, 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.

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 106a 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 106a to vary the pivot angle of the pivot mount 126 to thereby position the nip roller 106a 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 108a. 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 106a 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 106a is actively driven.

The configuration shown in FIG. 5 is present for each of the nip rollers 106a-d across the width of the assembly 100. The geometry of this arrangement is such that each of the nip rollers 106a-d and their trolleys 108a-d can be adjusted to define a nip gap 112a-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 106a-d to drive them with little or no effect on their respective nip gaps 112a-d.

More specifically, each of the nip rollers 106a-d across the width of the assembly are adjusted and set in place to provide the desired nip gap 112a-d with the first drive roller 102. Thus, the nip rollers 106a-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 106a-d even though they are not necessarily co-axially with one another. Thus, some of the rollers 106a-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 106a-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 106a-d.

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 106a-d relative to each other to obtain the desired nip gap and web control.

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 106a-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 106a-d to achieve a different sized nip gap 112a-d when frictionally driven by the second drive roller 110.

In summary, a new and novel paper web transport assembly 100 is provides that includes more than two actively driven nip rollers, such as 106a-d. Each of the nip rollers 106a-d can be adjusted to provide a desired nip gap between it and an opposing driven roller 102. The nip gaps 112a-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.

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.

Claims

1. A transport assembly, comprising:

a support;

a drive roller rotatably mounted to the support about a drive roller axis; the drive roller having a drive roller outer surface and a width;

means connected to the drive roller for rotating the drive roller about the drive roller axis;

a nip roller adjustably mounted to the support about a nip roller axis; the nip roller having a nip roller outer surface and a width; the nip roller being positioned adjacent to the drive roller with the drive roller outer surface being in frictional communication with the nip roller outer surface;

whereby rotation of the drive roller drives the nip roller about the nip roller axis.

2. The transport assembly of claim 1, wherein the drive roller axis is substantially parallel to the nip roller axis.

3. The transport assembly of claim 1, wherein the nip roller is connected to the support by an adjustable pivot mount.

4. The transport assembly of claim 1, wherein the width of the nip roller is less than the width of the drive roller.

5. A transport assembly, comprising:

a support;

a drive roller rotatably mounted to the support about a drive roller axis; the drive roller having a drive roller outer surface and a width;

means connected to the drive roller for rotating the drive roller about the drive roller axis;

a plurality of nip rollers each being adjustably mounted to the support and each having respective nip roller axes; each of the plurality of nip rollers having a respective nip roller outer surface and a width; the plurality of nip rollers each being positioned adjacent to the drive roller with the drive roller outer surface being in frictional communication with each nip roller outer surface of the plurality of nip rollers;

whereby rotation of the drive roller drives the plurality of nip rollers about their respective nip roller axes.

6. The transport assembly of claim 5, wherein the drive roller axis is substantially parallel to each of the nip roller axes.

7. The transport assembly of claim 5, wherein the nip roller axes are not co-axial with each other.

8. The transport assembly of claim 7, wherein each of the plurality of nip rollers are connected to the support by an adjustable pivot mount.

9. The transport assembly of claim 5, wherein the plurality of nip rollers are positioned in spaced apart relation to one another across the width of the width of the drive roller.

10. An assembly for transporting a web having a width, comprising:

a support;

a first drive roller rotatably mounted to the support about a first drive roller axis; the first drive roller having a first drive roller outer surface and a width;

means connected to the first drive roller for rotating the first drive roller about the first drive roller axis;

a plurality of nip rollers each being adjustably mounted to the support and each having respective nip roller axes; each of the plurality of nip rollers having a respective nip roller outer surface and a width; the plurality of nip rollers each being positioned in spaced apart relation and adjacent to the first drive roller with the first drive roller outer surface being in frictional communication with each nip roller outer surface of the plurality of nip rollers; the plurality of nip rollers being driven by the first drive roller drives about their respective nip roller axes;

a second drive roller rotatably mounted to the support about a second drive roller axis; the second drive roller having a second drive roller outer surface and a width; the second drive roller outer surface being positioned a distance from the each of the first nip roller outer surfaces defining a split nip gap therebetween; the web being receivable through the split nip gap;

whereby the split nip gap distance between each of the plurality of nip rollers are individual adjustable and directly driven by the first drive roller.

11. The assembly of claim 10, wherein the first drive roller axis is substantially parallel to each of the nip roller axes.

12. The assembly of claim 10, wherein the nip roller axes are not co-axial with each other.

13. The assembly of claim 12, wherein each of the plurality of nip rollers are connected to the support by an adjustable pivot mount.