Winding – tensioning – or guiding – Material guide or guard – Variable guide path
Reexamination Certificate
1999-11-09
2004-12-14
Jillions, John M. (Department: 3653)
Winding, tensioning, or guiding
Material guide or guard
Variable guide path
C242S615200, C226S023000
Reexamination Certificate
active
06830212
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to surface winding and unwinding of cloth, paper, metal, or plastic webs and the like from web rolls. The present invention utilizes an equalizing roll to be used in manufacturing for providing equal tension across a web, belt, or sheet of material during winding and conveying operations such as used in polymer film processing applications, corrugators, paper machines, printing presses, cloth winders and metal winding operations.
2. Background Information
The present invention comprises an equalizing roll which may be used as a stand alone unit or in a tracking apparatus for stabilizing the run of a material web which is being rolled off of or onto a drum or through a series of rollers. The present invention is designed to provide a method of optimally stabilizing, controlling the tension, controlling the slack, and the direction of a web, belt or sheet of material while the web is traveling between rolls.
One application is in the drying section of a high speed paper machine where the paper web to be dried meanders over drying cylinders. The present equalizing roll is also useable in connection with a “transfer foil”, i.e. a device for transferring the paper web from the press section to the drying section such as described in U.S. Pat. No. 4,551,203 [Eskelinen]. The present invention may also be utilized for stabilizing and controlling the tension of a paper web of paper coaters. It is contemplated that the present invention can also be used in the fabric industry; plastics film, sheet, and tape industry; and in the metal film and foil industry. The invention may be used in small diameter, narrow width applications measurable in centimeters on inches or industrial operations wherein the rolls may extend thirty to fifty feet in length or longer depending on the application.
The equalizing roll of the present invention in the paper industry solves the problem of wrinkles and slack being formed in the paper or plastic film web during processing by an apparatus such as is described in U.S. Pat. No. 4,441,263 [Vedenpaa]. The present invention provides a means to control the pressure conditions in the area where the paper web runs together with a backing belt on a receiving drying cylinder and across the entire width of the paper web extending across the entire length of the drying cylinder or other such conveyor assembly. As is generally known, air flow transverse to the drying section causes the edges of the paper web to flutter and/or the formation of wrinkles in the paper web as shown in FIG.
1
. This occasionally causes the paper web to break or a plastic web to be stretched and permanently distorted. A stable, smooth run of the paper web requires that the forces resulting from the longitudinal tension of the paper web be equal. The longitudinal tension on the paper web caused by the drying cylinder in combination with a backing belt creates a region in the paper web where the curvature is irregular as viewed across the width of the paper web. In the center, the paper web bows out more heavily than on the edges resulting in stretching and deformation of the web.
Another application for the present invention is in the cloth industry to avoid wrinkling cloth being unwound from rolls on surface winders and unwinders, batchers, cradle let-offs and the like. As set forth in U.S. Pat. No. 5,431,358 [Alexander], hereby incorporated by reference, in the area where the support rolls engage the cloth roll, the cloth roll is indented presenting a shorter cloth roll radius at that point than the radius in the unengaged areas of the roll resulting in the formation of a bulge or bagging down in advance of the support roll. Sometimes, the bulge or loose pucker resulting from such bagging down advances entirely about the wound roll causing wrinkling, marking and uneven tension.
U.S. Pat. No. 1,738,170 [Cohen], U.S. Pat. No. 3,433,429 [Schnitzspahn] and U.S. Pat. No. 4,026,487 [Ales] illustrate efforts to solve the problem through compressible support roll covering wherein an effort is made to match the compressibility of the support roll to the compressibility of the wound web roll. An inflatable support roll and other efforts to solve the problem include uniform or continuously spaced fluting on the support rolls. Such fluting may be skewed or spiraled in respect to the longitudinal axis. A roll having spaced segments is illustrated in U.S. Pat. No. 1,093,913 [Church], whereas U.S. Pat. No. 3,239,163 [Ciniglio] illustrates uniformly spaced compressible fluting having upper surface areas conforming to the curvature of the flexible roll. Attempts to match or otherwise utilize the relative compressibility of the support rolls in relation to the compressibility of the wound rolls have met with limited success. Fluted rolls having uniform circumferential spacing result in vibration or chattering and sometimes mark the wound rolls with the pattern of the fluted segments due to the limited areas of support.
The present invention provides an equalizing roll means to equalize the tension of the web as the web runs over the rolls distributing the lateral forces so that any imbalance of lateral tension will cause the roll to pivot at its center permitting the roll to move forward on the side of least tension until the web tension is equalized across the entire roll.
SUMMARY OF THE INVENTION
The equalizing roller of the present invention is a universal mount idler roll that works off of a center pivot point and is able to swivel a selected amount preferably in a range of from about 0° to about 15°. The, equalizing roll is placed before or after, and in alignment with, a plurality of idler rollers having a web roll or belt of material in order to maintain a constant tension of the web or sheet of material unrolling from a web roll to prevent stretching or wrinkling of the material and facilitating off rolling of the material in a straight line so that the sheet or ribbon does not want to veer to one side. Moreover, the tracking apparatus may be used in conventional conveyor assemblies to provide directional stability to a belt, sheet, or web of material being conveyed over at least one equalizing roll.
In one embodiment of the present invention, a common axis shaft is rigidly clamped to support means preventing rotation. In some applications it may be desirable to support the shaft on two shaft support bearings providing for rotation; however, oscillation may occur if the roll is not perfectly balanced or if the pivoting-rotary bearing has experienced wear making control of the roll difficult. Mounted in the center of the shaft is a self-aligning pivoting-rotary bearing assembly having an inner convex ball and an outer concave socket portion disposed within a housing sleeve. The single center pivoting-rotary bearing assembly is mounted inside a hollow cylinder or roll machined to be in balance with respect to the centrally disposed pivoting-rotary bearing assembly. The mating of the concave and convex portions of the pivoting-rotary bearing permits a selected degree of lateral rotation and allows the roll to rotate independently of the shaft. As the web runs over the roll, any imbalance of lateral tension will cause the roll to pivot at its center permitting the roll to move forward on the side of least tension until the web tension is equalized across the entire roll.
More particularly, the present invention provides an equalizing roll for controlling web tension including a longitudinal shaft having distal ends rotatably supported by a pair of shaft support bearings, a self-aligning center pivoting-rotary bearing assembly having an inner ball portion fixedly connected to the weighted center of the shaft and an outer socket portion fixedly connected to the weighted center of the cylindrical roll coaxially mounted around the shaft, wherein the deflection of the roll with respect to the shaft is in the range of from about 1° to about 10°, and most prefera
Jillions John M.
Piltch, Esq. Sanford J.
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