Method And Apparatus For Improved Web Transfer

Abstract

Improved method and apparatus for obtaining transfer of a web from a parent roll to sequentially supplied cores for rewinding. A transfer roll having a deformable surface is utilized in combination with a piston or the like for urging the individual cores against the web and the transfer roll surface. The deformable surface provides increased wrap of the web around the core and insures smooth web transfer without excessive wrinkling. In a preferred embodiment a phase shift differential arrangement is included to adjust the location of sheet or web separation upon breaking.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The manufacture of consumer-sized rolls of products such as sanitary bathroom tissue, paper toweling or the like, customarily involves the rewinding of relatively short lengths from large rolls produced by paper machines onto cores which are slit into sizes convenient for home use. In the cases where the product is to comprise two or more plies or sheets, a corresponding number of paper machine (parent) rolls are simultaneously unwound so that the sheets are in a face-to-face position when rewound. If desired, the plies may be bonded together by use of embossing, light adhesive application or the like. In order for this winding operation to work efficiently, it must take place at high speeds and on a generally continuous basis. This invention is related to improvements in methods and apparatus for transferring the web to a new core from a previously completely wound core without causing excessive wrinkling of the web.

2. Description of the Prior Art

Various apparatus have been devised to provide a continuous succession of cores for winding in a manner such that the speed of the parent roll may be continuously maintained at lineal velocities of up to 1,800 feet per minute and even higher. In most cases, the web is unwound into partial wrapping engagement with a transfer roll. Adhesive is usually applied to an empty core, and the sheet transferred thereto by contact between the core and the sheet on the transfer roll. In one form of apparatus for obtaining transfer of the sheet from the transfer roll to a new core, a tucker is utilized. This tucker is driven very quickly against the web forcing it outward from the transfer roll into contact with the new core. This action is usually quite violent and accomplished with a solenoid-operated hydraulic cylinder at about 600 to 700 p.s.i.g. line pressure. The very anture of the violent action has caused missalignment and maintenance problems as well as safety hazards and noise.

A second commonly used system involves mounting the cores on a turret and rotating them into position for contact with the web on the transfer roll. As this necessitates essentially a point-to-point contact, it has frequently resulted in excessive wrinkling of the web as it is first transferred to the core.

Reference may be had to U.S. Pat. No. 2,357,976 to Roesen; U.S. Pat. No. 2,769,600 to Kwitek et al. and U.S. Pat. No. 2,973,158 to Zernov for specific examples and further description of such methods and apparatus.

SUMMARY OF THE INVENTION

Briefly, in accordance with the present invention, in both single ply and multiple-ply operation improved sheet transfer to a new core is obtained by providing a transfer roll having a deformable surface combined with a piston or the like for forcing new cores against the deformable surface. As the web is being transferred to a new core from a previously fully wound one, the core contacts the web against this deformable surface and results in a partial wrap of the web around the core as the surface is deformed. This maintains the sheet in a smooth condition and insures clean, substantially wrinkle-free web transfer to the new core when the web is broken between the new core and the fully wound core. In this manner, the violent actions required of the tucker blades are rendered unnecessary since the core may be withdrawn more gradually, and the point-to-point contact which results from the use of previous turret-type apparatus and arrangements is also avoided. In accordance with conventional practice, a knife roll may be further used to provide perforations, and a phase shift differential transmission may be utilized to adjust the distance between the perf blade and the transfer roll, thereby insuring separation of the web between the cores at a desired line of perforation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall perspective view of one form of the transfer apparatus of the present invention;

FIG. 2 is a schematic side view of the apparatus of FIG. 1 in combination with one form of a phase shift differential;

FIG. 3 is a detailed partial perspective view of a phase shift differential transmission;

FIG. 4 is a detailed schematic view of the transfer operation;

FIG. 5 is a partially cut away view showing in perspective the transfer apparatus including air cyinders for urging the cores into position; and

FIG. 6 schematically illustrates how the present invention may be incorporated into an overall winding system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the invention will be described in connection with preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Turning first to FIGS. 1 and 2, the improved web transfer apparatus of the present invention will be described. These drawings illustrate the winding and transfer assembly immediately prior to transfer. The overall assembly includes supporting members generally indicated 10 which have been largely eliminated from the drawings for clarity but may be of conventional frame design. It may be divided into phase shift differential transmission section 12, and transfer section 14 both of which have transfer roll 22 in common. The phase shift differential section includes knife roll 16 (FIG. 2), adjusting gear 18 which includes a differential gear train (FIG. 3). Timing belt pulleys 20, 21, 23, and 25 tie the transfer roll in driving relationship with the knife roll. The transfer section includes transfer roll 22 on shaft 19, which also has bearing 29 for rotation in support 10 on shaft 80, deformable surface 24, winding belt assembly 26 including pulleys 28 stepped for shouldering belts 66 and journalled for rotation by bearing 27 on shaft 31 which has bearings 81. Belt 66 drives cores 30 on core shaft 78. Air cylinders 32 urge the winding belt assembly and the core against the transfer roll 22 at timed intervals. An arrangement such as chain transport 50 is provided as shown in greater detail in FIG. 6 for moving the cores into and out of winding positions.

Turning now also to FIGS. 3, 4, and 5 in conjunction with FIGS. 1 and 2, the operation of the method and apparatus for the present invention will be described in greater detail. Web 38, which may be slit along lines 39, if desired, is fed to knife roll 16 and then to transfer roll 22. Cores 30, which are preferably pre-glued and driven by contact with belt 66 are made of a suitable material such as cotton-duck backed natural rubber of 40 to 45 Shore A Durometer hardness, for example. They traverse past the transfer roll 22 at a rate timed to the number of sheets of web 38 for total web length required on the completed wound roll 42. Rotation of the cores and winding of the web 38 results from contact with driven belt 66. Adjustment of tension of belt 66 is provided by slide block 68 engaged for movement within tracks 70 and threaded adjusting rod 72 including adjusting nut 74 and locking nut 75. The pickup point, or the location at which the core contacts the transfer roll at transfer, is generally indicated at 36 (FIG. 2). To initiate the transfer, the air cylinders 32 connected to support 10 by clevis bracket 33, pin 35 through eye 37 bracket are activated, pivoting the winding belt assembly 26 about support pin 76 and connecting clevis pin 84 having suitable bearings 77, 79 and forcing core 30 against the deformable surface 24 of transfer roll 22 with the web 38 impinged between core 30 and deformable surface 24. Web 38 adheres to the core 30 and wraps around it, applying tension to the web between the core 30 and the fully wound core 42, eventually breaking the web at a perforation 40 (FIG. 4) thus completing the fully wound roll 42 and beginning the wind on new core 30. Core 30 is preferably held in contact with transfer rool 22 for a brief period, for example 3 to 4 core revolutions, and then is backed away at a controlled rate to assure good transfer and proper winding belt pressure.

As is evident from the drawings, the deformable surface of transfer roll 22 allows the core 30 to impress itself into the surface 24 giving increased surface contact and wrap which aid in the attachment of web 38 to core 30. Furthermore, deformable surface 24 acts as a shock absorber to cushion the force of the sudden motion of core 30 into the transfer position, thereby decreasing noise and increasing the life of the winding belt 66.

The phase shift differential transmission section 12 provides control of the perforation location at the time web 38 is broken. This is accomplished by means of the differential gear train mounted on support 10 (FIG. 3) with external adjustment handle 64 that allows the output shaft 46 to be infinitely adjustable rotationally with respect to input shaft 48 through timing pulleys 44, 62 while maintaining a constant speed ratio. Drive pulley 82 connected to a suitable power source (not shown) provides the drive for the winding belt 66. Similarly, the transfer roll 22 may be driven through a belt and pulley arrangement or by direct drive (not shown). Additionally, adjustment can be made either statically or dynamically so that only one sheet of the web will contact core 30 and so that the perforations 40 will be located for most reliable transfer through increasing or decreasing the distance between cutting blades 60 on knife roll 16 and transfer roll 22. Such phase shift differential transmission equipment will not be described in greater detail as it is known and available, for example, Model OOPSD from Specon as described in its Phase Shift Differential Transmission Bulletin No. 205C. With this feature, it is possible to drive the knife roll by the transfer roll through the phase shift differential transmission by the pulley arrangement as generally indicated in FIG. 3.

Knife roll 16 may be any one of a number of conventional constructions and will not be described in detail. It essentially includes blades 60 that contact web 38 at selected intervals to weaken the sheet strength at those locations. The blade 60 normally need not be sharp and may be serrated in the manner shown, as is well-known, to provide the desired degree of sheet strength reduction. Usually it will be desirable to provide an opposing surface such as an idler roll (not shown) or anvil 88 on support 90 so that the blades 60 may impinge web 38 against a surface for increased effectivnesss.

Preferably, the drive belt 66 for cores 30 is on the edges only to avoid contact with adhesives applied to the cores. While a single drive belt may be used, it is preferred to have at least a drive belt on each end for balanced operation and others as the length of the shaft may dictate (FIG. 5). The separation distance between core 30 and transfer roll 22, prior to contact, is preferably at least about 3/4 of an inch. The deformable surface is preferably substantially continuous around the transfer roll cross sectional circumference and composed of foam rubber such as medium density Durkee-Atwood open cell natural rubber foam sheeting and may simply be adhesively attached to the roll surface. Other materials may be utilized as well. It is preferably about 1/4 inch to 3/4 inch thick for shock and noise reduction. The preferred hardness of the deformable layer depends substantially upon the pressure applied by the piston as transferred to the core. Generally this will be in the range of from about 2 to about 5 pli for the winding of toilet tissue or the like. In such cases the Shore A hardness of the deformable surface may be in the range of from about 5 to about 20 with from 8 to 12 Durometer preferred. Where the applied pressures are greater or less, it will be recognized that the hardness may vary outside these ranges. It is important, however, that the core deform the surfaces sufficiently to produce significant area contact between the web and the core. Preferably this takes place over an arc subtended by from about 15.degree. to about 90.degree. on the core cross section.

Turning to FIG. 6 the application of the invention to improve the operation of a complete rewinder system will be described. In this arrangement the cores are supplied by chain link 50 which is driven counter-clockwise by sprockets 52, powered by a conventional source (not shown). There are nine core stations 54A to 54I for sequential operative steps. Cores 30 are provided at 54A, adhesive applied at 54E by a roll coater consisting of dip pan 56 and mist roll 58. At step 54G sheet 38 contacts core 30 and is transferred from finished roll 42 by the transfer section 14 as previously described. Finished roll 42 proceeds to step 54I where it is removed and the cycle repeated.

The advantages of the present invention include highly reliable web transfer, increased belt life, quieter operation with less maintenance, and reduced tendency to form wrinkles at the core.

Means for timing and activating apparatus such as the present invention are known and will not be described. It is only necessary that controls be provided that are capable of quick response for maximum benefits to be derived. However, the selection of any particular system is not critical and will depend upon the application involved. For example, core 30 may be forced against the deformable surface 24 through web 38 without moving the belt assembly 26. However, it should be recognized that it is usually desirable to have the core rotating at the same peripheral speed as the rate of movement of the web. For that reason, it is preferred that contact between belt 66 and core 30 be maintained.

While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and broad scope of the appended claims.

Claims

I claim:

1. Apparatus for transferring a moving web successively onto cores for rewinding said web comprising,

means for receiving said web,

a transfer roll having a deformable circumferential surface,

means for receiving cores and positioning them sequentially adjacent said transfer roll,

means for rotating said sequentially positioned core at about the same circumferential speed as the linear rate of web travel,

means for moving and urging said sequentially positioned core against said deformable transfer roll surface to pick up said web and cause it to be wound onto said core, and for moving said core away from said transfer roll, and

means for removing fully wound cores.

2. The apparatus of claim 1 wherein said deformable surface has a Shore A hardness in the range of from about 5 to 20.

3. The apparatus of claim 1 further including means to perforate said web.

4. The apparatus of claim 1 wherein said urging means comprises a piston adapted to move the means for rotating the cores and the cores towards said transfer roll.

5. The apparatus of claim 1 wherein said means for rotating said cores is a driven belt.

6. The apparatus of claim 1 wherein the area contact produced by said urging means takes place over an arc subtended by an angle of from 15.degree. to 90.degree. on the core cross section.

7. The apparatus of claim 1 further including means for applying adhesive to said sequentially supplied cores.

8. An improved method for transferring a moving web successively onto cores for rewinding said web comprising the steps of,

passing said web into partial wrapping engagement with a transfer roll having a deformable surface,

positioning cores sequentially adjacent said transfer roll,

rotating said sequentially positioned core,

moving and urging said sequentially positioned core against said deformable transfer roll surface thereby picking up said web and causing it to be wound onto said core,

moving said core away from said transfer roll,

removing said core when fully wound.

9. The method of claim 8 further including the step of applying adhesive to said core prior to urging it against said web.

10. The method of claim 8 wherein said cores are urged against said deformable transfer roll surface for a period of time required for about 3 to 4 core revolutions.