Roll winder and process of operating same

Details Roll winder and process of operating same Roll winder and process of operating same

1999-01-27

2001-03-06

Walsh, Donald P. (Department: 3653)

Winding, tensioning, or guiding

Convolute winding of material

With particular drive

C242S533300

Reexamination Certificate

active

06196492

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to a roll winder including a roll retainer, which is coupled to a wound roll in the region of its pivot axis, to a support apparatus, and to a process.
2. Discussion of Background Information
Beyond certain roll diameters, roll winders, which are provided to hold a roll in a region of its pivot axis, require that the wound roll be supported from below. Otherwise, under the influence of its own weight, the wound roll would sag too much, which can lead to damage to the web of material.
However, supporting the wound roll from below leads to the problem that the bearing pressure has an influence on the winding hardness. In particular, for take-up winding, the influence of bearing pressure on the winding hardness can lead to undesired results. In principle, it is desirable to have the winding hardness decrease from the inside out. However, with increasing bearing pressure, winding hardness increases from the inside out, i.e., contrary to the desired effect.
Some suggestions have already been made in the prior art for addressing this problem. For example, one proposal is based on supporting the wound roll on an air cushion. However, this is relatively energy-intensive. Another solution is to arrange the wound roll on a revolving belt that is tensed between two deflection rolls, which sometimes causes considerable wear.
SUMMARY OF THE INVENTION
The present invention provides a device for supporting a wound roll that does not suffer from the above-noted drawbacks of the prior art.
In a roll winder of the type generally discussed above, a support apparatus is provided having a plurality of roll bodies with axes extending parallel to the pivot axis of the wound roll and which are combined into pairs of rolls. Each pair of rolls are pivotable about a shaft that extends parallel to the pivot axis.
In this manner, because the wound roll is always supported on or by a plurality of roll bodies, the bearing force is distributed over a plurality of bearing faces. Correspondingly, the resultant contact pressure remains within allowable limits. Because the pairs of rolls are pivotable, they automatically adjust to adapt to the circumference of the wound roll. This ensures that the wound roll will rest on the roll bodies. When the wound roll diameter is small, the individual roll bodies are loaded differently. However, this is not critical, since at a smaller diameter the force of gravity of the roll is also less. Hence, the contact pressure remains low. The greater the diameter of the wound roll becomes, the more uniformly the roll bodies are loaded. In other words, the roll bodies take part in distributing the bearing force, which limits the force per bearing point.
Preferably, two pairs of rolls may be arranged on a pivotable rocker, whose pivot shaft extends parallel to the pivot axis. The rocker permits a largely uniform support of the wound roll by the roll bodies even if the wound roll is not located symmetrically between the roll pairs. In such a case, the rocker may be inclined somewhat. Moreover, a plurality of rockers can also be provided, which then, because they are pivotable, can adapt to the diameter of the wound roll.
Advantageously, the roll pairs may be spaced apart from one another on the rocker and located under the wound roll in the direction of gravity by a distance at which the respective outer roll bodies are less than approximately 800 mm away from each other. The magnitude of approximately 800 mm has been selected because, beyond this diameter, the dead weight force becomes so great that support from below becomes necessary. If the two outer roll bodies are less than 800 mm away from one another, then beyond this diameter in the take-up winding process, or down to this diameter in unwinding, the wound roll is supported by all the roll pairs.
Advantageously, the rocker may be arranged on a carrier that is pivotable about a pivot shaft extending parallel to the pivot axis. The arrangement has advantages, particularly if the pivot axis of the wound roll remains in the same plane, e.g., when the roll retainer is arranged in stationary fashion. In this case, the change in diameter upward or downward can be followed by pivoting of the carrier.
Advantageously, the pivot shaft of the carrier is stationary, and a connection point of the carrier to the rocker may then describe a circular arc. In many cases, the arc can be placed so that, e.g., in unwinding, it corresponds to a portion of a circle disposed in the vicinity of a vertically extending tangent. In this case, the support of the wound roll by the roll bodies remains largely symmetrical. Furthermore, the stationary support of the pivot shaft of the carrier makes construction simpler.
Preferably, the carrier may include a carrier pivot drive mechanism. In the unwinding operation, the carrier pivot drive mechanism can guide the roll bodies to follow the decreasing diameter of the wound roll and can ensure that the wound roll is always sufficiently supported from below. in the take-up winding, the pivot drive mechanism can lower the carrier, so as to establish the desired force ratios.
In an advantageous embodiment, it is provided that the spacing of the roll bodies within the roll pairs and the spacing of the bearing points of the wound roll from the pivot shafts of the roll pairs may be adapted to the spacing of the individual pivot shafts so that, with increasing diameter, the wound roll is supported substantially symmetrically to its vertical center plane. Such an embodiment may be especially advantageous when a support apparatus is used in a winding operation in which a central roll is provided to bear against the wound roll in winding procedure. The contact pressure of the wound roll against the central roll primarily determines the winding hardness. As the diameter of the wound roll increases, the pivot axis of the wound roll moves farther away from the central roll, however, the pivot axis remains in the same horizontal plane as the pivot axis of the central roll. As a result, the lowest point of the wound roll moves obliquely downward along a straight line at an angle of 45°. The carrier, which is pivotable about a carrier pivot shaft, executes a circular motion. However, the wound roll does not rest against the pivot shaft of the rocker, but against the roll bodies, which are spaced apart from this pivot shaft and are still separated by the pivot shaft of the roll pairs. Because of the latter pivot shaft, the circular motion of the carrier is somewhat compensated for by a counter-pivoting of the roll pairs, so that the contact points of the wound roll body extend in such a way that at least approximately largely symmetrical loading is assured. This loading can be limited to certain diameter ranges of the wound roll, e.g., within a range of approximately 800-1500 mm in diameter.
In an advantageous embodiment, the rocker may be pivotable relative to the carrier by an angle on the order of magnitude of from approximately 50° to 100°. Particularly in the winding operation, one roll pair of the support apparatus can then be used to press the winding tube of the wound roll and the wound roll, when the winding roll diameter is small, against the central roll so that the high winding hardness desired can be established at the outset of the winding operation. Moreover, in this way, sagging of the winding tube or wound roll due to web tension and from the contact pressure of the roll retainer when the roll diameter is small can be prevented. However, care should be taken to enable the roll body to exert a substantially horizontally oriented force on the wound roll, which is accomplished by the pivotability of the rocker relative to the carrier.
It may be preferred to position a rocker pivot drive mechanism between the carrier and the rocker. With the aid of the rocker pivot drive mechanism, the requisite adjustment of the rocker relative to the carrier and the requisite force on the winding tube or wound roll with the small diameter can th

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