US 3410499 A
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Nov. 12, 1968 w. J. SCHMIDT WEB MATERIAL WINDING APPARATUS Filed April 15, 1965 INVENTOR. M7]! J Scfimz'df flak-u ATT IVE) United States Patent 3,410,499 WEB MATERIAL WHNDING APPARATUS Willi J. Schmidt, Kelkheim, Taunus, Germany, as-
signor to Kalle Aktiengesellschaft, Wiesbaden-Biebrieh, Germany Filed Apr. 15, 1965, Ser. No. 448,531 Claims priority, application Germany, Apr. 17, 1964, K 52,723 4 Claims. (Cl. 24267.1)
ABSTRACT OF THE DISCLOSURE The present invention relates to a process and an apparatus for winding up webs of material, e.g., small tapes of synthetic plastic film, wherein winding is effected with straight edges and a particularly suitable web tension The apparatus of the invention includes a guide roller, a driven winding core of a series of driven winding cores mounted side-by-side, the distance of which from the guide roller may differ correspondingly to the increasing radius of the winding roll, one or several transmission rolls, depending on the number of webs which are incorporated between the guide roller and the corresponding wind-up roll in a loop of the web, which are not otherwise supported and which are at least as long as the web is wide. The width of the gap between the outer surface of the guide roller and the outer surface of the wind-up roll is maintained smaller than the diameter of the transmission roll.
In practice, it is necessary for many purposes to divide large webs of material into small webs, the large web of material usually being unwound and cut into the desired number of smaller webs, which are then immediately rewound. The winding cores necessary for the windingup operation are usually mounted on two driven shafts and the cut webs are distributed thereon in such a manner that neighboring webs are conveyed to winding cores which are not mounted on the same shaft. The winding cores also may be mounted on more than two driven shafts or individually on rocking levers. This arrangement has been used especially when using insertion rolls with different winding tensions. Almost every known apparatus is provided with at least one guide roller between the unwind and the wind-up rolls.
Two methods are generally known for winding-up longitudinally cut webs of material parallel to each other. When employing the so-called contact-free winding process, the winding cores mounted on a driven winding shaft are not in contact with the guide roller which conveys the webs of material to the wind-up rolls on the winding cores. Between the winding rolls, the diameter of which steadily increases, and the guide roller, a small constant distance is maintained in order to more successfully equalize the irregularities in the unwind roll, which, among other things, cause different diameters of the rolls to be rewound. This distance is relatively small but entails inexact conveyance of the Webs and, therefore, lateral conveyance of the web tapes often can not be prevented. Furthermore, air and dust may be included in the Wind-up rolls. When air is included as a uniform film, the rolls are too loosely wound and the film layers may slideslip on the air cushion. Incomplete removal of the air and compression in some places, by the upper winding layers and the tension of the web, result in blisterlike bulges on the periphery of the roll which later may adversely cause a permanent distortion of the web.
When employing the so-called contact-winding process, winding cores mounted on a common shaft contact the last guide roller from which the web tapes are conveyed to the winding cores, in order to avoid the disadvantages of the contact-free winding method. Despite the tension of the web, an unequal increase of the diameter of the individual winding rolls can not be prevented because of the different winding tensions in some parts of the unwind roll. The rolls with the greatest diameter thus determine the contact and the high contact pressure involved, together with the high moment of inertia of the common winding shaft, leads to strong pressure points of the rolls concerned. The thinner unsupported rolls, however, are likely to swing and include air in a manner similar to that of the contact-free process. The operators requirements of wound rolls with straight edges, i.e., tightly wound without including air and dust, thus can not be met by both of the above processes.
The process of the present invention simultaneously uses the system and advantages of the contact-free process as well as of the contact-winding process but eliminates the disadvantages of both.
When employing the process of the invention for winding up webs of material, which are, if desired, repeatedly deviated prior to being Wound up, the clearance between the last guide roller and the wind-up roll, analogously to the contact-free winding method, remains constant by employing known means. The web of material, on its way between the last guide roller and the Wind-up roll, is conveyed in the form of a loop over a transmission roll supported only in this loop, i.e., being otherwise unsupported, and the constant clearance between the guide roller and the wind-up roll is kept smaller than the diameter of the transmission roll, the transmission roll being moved by contact pressure, resulting from the web tension, at a speed corresponding to that of the web. The transmission device can not move inside the loop because of the limited distance between the guide roller and the wind-up roll.
The continuous conveyance of the web in accordance with the process of the invention ensures complete removal of air so that no air is included during the winding operation. The wind-up process of the invention is particularly suitable for winding up two or more webs of material running side-by-side, as occurring, for instance, when dividing a large web of material into two or more small webs.
An apparatus for performing the process of the invention comprises a guide roller, a driven winding core or a series of driven winding cores mounted side-by-side, the distance of which from the guide roller may differ correspondingly to the increasing radius of the wind-up roll, one or several transmission rolls, depending on the number of webs, which are incorporated between the guide roller and the corresponding wind-up roll in a loop of the web, which are not otherwise supported and which are at least as long as the web is wide.
The width of the gap betwen the guide roller and the wind-up roll is smaller than the diameter of the transmission roll. The length of the transmission roll is as great as, or advantageously somewhat greater than, the width of the web to be wound up in order to make a slight lateral movement of the transmission roll possible. The transmission roll may be cylindrical or slightly spherical. Light, rigid material, e.g. aluminum, is preferably used for the fabrication thereof. Particularly suitable are roll-like transmission devices with an elastic surface layer such as rubber or synthetic plastic, e.g., polyethylene, polytetrafluoroethylene or polyamides.
The invention will be further illustrated by reference to the accompanying drawing in which one embodiment of the Winding apparatus of the invention is schematically shown.
A web 1 passes over the guide roller 2, then winds around the transmission roll 3 which, by means of the web tension, is maintained in contact with the guide roller 2 as well as with the winding roll 4, and is then Wound onto the Winding roll 4. The winding roll 4 is driven by means of the winding core 5 so that a certain tensionof the web, and thus simultaneously a certain contact pressure of the transmission roll, can be adjusted at the winding roll and the guide roller. The winding core 5, together with the Winding shaft, is suspended and swings around an axis 6 so that, in spite of the increasing diameter of the wind-up roll, the distance between the top layer of the Winding roll and the guide roller 2 remains constant, by using conventional means.
By means of the process of the present invention, Webs of material other than plastic films, which are particularly suitable, may be Wound up, e.g., from paper, cellophane, metal and the like. The rolls thus obtained are distinguished by edge-straight winding and do not show defects caused by inclusion of air. The practically perfect yield of excellently wound materail, based on the rolls used, shows the superiority of the process of the invention as compared with conventional winding processes.
It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
What is claimed is:
1. An apparatus for winding a web of material onto a wind-up roll which comprises at least one guide roller, at least one driven wind-up roll, at least one transmission roll having a length at least equal to the Width of the 4 web .and being supported only by the web passing from the guide roller to the wind-up roll and being in engagement with said guide roller and said Wind-up roll, and means for increasing the center-to-center distance between the guide roller and the wind-up roll While maintaining the distance between the peripheries thereof less than the diameter of the transmission roll and the transmission roll in engagement with the guide roller and the Wind-up roll.
2. An apparatus according to claim 1 in which the transmission roll is fabricated from a light, rigid material.
3. An apparatus according to claim 1 in which the transmission roll has .a resilient material on the surface thereof.
4. An apparatus according to claim 1 in which the means for increasing the center-to-center distance between the gnide roller and the wind-up roll includes means for moving the wind-up roll relative to the guide roller.
References Cited UNITED STATES PATENTS 1,964,076 6/ 1934 Petersen et al 242- 2,135,668 11/1938 Judelshon 242-67.1 X 2,702,772 2/1955 Pronio 24265 X 2,777,644 1/1957 Nicholson 242-56.9 X 3,240,442 3/1966 Kilmartin 242-66 GEORGE F. MAUTZ, Primary Examiner.