Roll or roller – With antideflection means – Rotatable relative to supporting shaft
Reexamination Certificate
2001-03-30
2003-02-25
Rosenbaum, I Cuda (Department: 3726)
Roll or roller
With antideflection means
Rotatable relative to supporting shaft
C492S001000, C492S016000
Reexamination Certificate
active
06524228
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a roller for the pressure treatment of a fabric web.
BACKGROUND OF THE INVENTION
A roller for the pressure treatment of a fabric web is known from German Patent 29 42 002 A1. In particular, FIGS. 9 through 12 of that patent show a roller which has a hollow cylinder that can rotate about an axis. A non-rotatable cross-head extends through the hollow cylinder. Lateral support elements are mounted on the cross-head. As a result of the lateral support elements, additional forces can be exerted on the hollow cylinder perpendicular to its active plane, i.e., in general, parallel to the web.
A roller for the pressure treatment of a fabric web is subject during operation not only to forces lying precisely in the active plane. Rather, forces also arise that are perpendicular to the active plane, whether as a result of the driving forces of the fabric web, or as a result of the deformation resistance of the latter, or as a result of incorrectly calculated driving power, when the roller is driven. If the driving power is set too high, it can lead, for example, to the roller tending to operate in advance contrary to the direction of motion of the fabric web, which, since the roller is generally fixedly supported at its ends, can lead to a deformation of the roller in a plane that is parallel to the web. The same applies in the case of insufficient driving power, if the web thus carries the roller along with it and deforms it in the direction of motion.
If relatively thin-walled roller tubes made of steel, or especially plastic, are used, (whose bending resistance is not very high in comparison to thick-walled rollers made of steel), all stresses perpendicular to the active plane lead especially to noticeable deformations in the roller in a plane that is perpendicular to the active plane.
A deformation-controllable roller having lateral support elements can be seen from German Patent AS 22 30 139, FIG. 9. In this roller, however, four mating rolls are arranged around the roller offset by 90° with respect to each other. The mating rolls, along with the roller, form four roller gaps. Therefore, the deformation of a free roller parallel to a web that is moving essentially in a planar fashion is not emphasized in this context.
In the known embodiments of rollers having lateral support elements, it is true that lateral forces can be exerted on the hollow cylinder by applying a predetermined pressure in the support element. However, in these embodiments, the position of the support element of the hollow cylinder is determined as a function of the equivalence of forces and is not established geometrically. Therefore, it is not possible, using the known embodiments, to position the hollow cylinder in a plane that is perpendicular to the active plane.
SUMMARY OF THE INVENTION
The object of the present invention is to design a deflection controlled roller so that a positioning of the hollow cylinder perpendicular to the active plane is achieved.
This objective in a first aspect is achieved by a roller which has a hollow cylinder that can rotate about an axis A and that supports the working roller periphery. A non-rotatable crosshead extends through the length of the hollow cylinder, leaving all around a distance with respect to the inner circumference of the hollow cylinder. The crosshead is supported at its ends on external support pieces. A support device is arranged on the crosshead and acts radially in the active plane of the roller against the inner circumference of the hollow cylinder. The support device transmits the forces necessary for creating the line forces exerted by the roller from the crosshead to the hollow cylinder. At least one hydrostatic support element is arranged laterally on the crosshead and acts radially perpendicular to the active plane of the roller against the inner circumference of the hollow cylinder. The hydrostatic support element is hydraulically extendable against the inner circumference of the hollow cylinder and has on the exterior side an arrangement of hydrostatic bearing pockets that are open with respect to the inner circumference of the hollow cylinder. The bearing pocket arrangement of the lateral support element can be supplied in a throttle-free manner with hydraulic fluid quantity that is constant over time. A mechanical limit stop is provided for limiting the lateral extension motion of the lateral support element.
The lateral support element is hydraulically extendable. However, the extension is only possible until the limit stop is reached. In this position, the support element stops. A quantity of hydraulic fluid that is constant over time and that escapes over the edge of the bearing pockets is continually conveyed into the bearing pockets. Between this closed, circumferential edge and the inner circumference of the hollow cylinder there is a certain gap. When, as a result of a deformation perpendicular to the active plane, the inner circumference of the hollow cylinder approaches the edge of the bearing pocket arrangement, stationary with respect to the crosshead, both the gap and the escape-flow cross-section provided by it are reduced, and the pressure in the bearing pocket arrangement rises. With it, there is also an increase in the force exerted on the inner circumference of the hollow cylinder by the support element counteracting the deformation of the hollow cylinder that has occurred. In this manner, an equilibrium is achieved. In this way, care is taken that the hollow cylinder is always in a predetermined position—seen from a point of view perpendicular to the active plane.
The predetermined position is determined by the position of the limit stop or stops. It is obvious that this position is selected such that in the normal case, i.e. when the hollow cylinder is not deformed perpendicular to the active plane, no forces acting to deform the hollow cylinder are exerted upon it. In the normal case, care is taken that the gap at the lateral support element amounts to roughly 0.5 mm. In the case of support elements opposite each other and perpendicular to the active plane, this gap is specified in both support elements.
This means, in normal operation, that the quantity of hydraulic fluid conveyed constantly over time to the bearing pocket arrangement can flow, in a practically pressure-free manner, into the interstitial space between the crosshead and the inner circumference of the hollow cylinder, from where it is continually drawn off. In normal operation, the lateral support elements are therefore in a practical sense not active. They only begin to carry out their function when the gap on one or the other side begins to change perpendicular to its active plane as a result of an undesirable deformation of the hollow cylinder. Then the pressure on the side having the decreasing gap rises, and a force is exerted upon the hollow cylinder in opposition to the deformation.
The length of the lateral support elements in the roller longitudinal direction amounts to roughly {fraction (1/100)} to {fraction (1/20)} of the length of the roller. In general, over the length of the roller there will be a few, e.g., three or four, given a normal roller length of 3 to 8 m, lateral support elements of this type, support elements of this type being situated opposite each other on both sides of the crosshead, assuming deformations of the hollow cylinder are possible in both directions.
As used herein the “bearing pocket arrangement” is taken to mean both an individual bearing pocket as well as a group of two, three, or four bearing pockets, introduced in the contact surface of the support element, which can be provided for balancing the forces on the support element.
The “mooring” of a hydrostatic support element at a predetermined maximum position using a mechanical limit stop is, taken by itself, known from German Patent 39 18 989 C1. However, in this context, a support element of a different type is involved, which is arranged in the active plane of the roller and aids in positioning the hollow cylinde
Cuda Rosenbaum I
Eduard Kusters Maschinenfabrik GmbH & Co. KG
Kenyon & Kenyon
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