Roll or roller – Rotatable relative to supporting shaft
Reexamination Certificate
1999-11-04
2002-02-05
Hughes, S. Thomas (Department: 3726)
Roll or roller
Rotatable relative to supporting shaft
C492S007000, C100S16200R
Reexamination Certificate
active
06344019
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a rolling contact cylinder device for subjecting webs to a pressure treatment. The device has a deflection-controllable cylinder that includes a hollow cylinder rotating around its axis and forming the working cylinder circumference. It is traversed lengthwise by a non-rotatable crosshead, clearance being maintained between the crosshead around the entire inner circumference of the hollow cylinder, and having an inner support device which is mounted on the crosshead and which acts on the inner circumference of the hollow cylinder. Outer bearings are provided, which support the ends of the crosshead at outer sidewalls and which have cooperating spherical surfaces for absorbing the deflection of the crosshead, one of which is attached to the crosshead and the other to the respective sidewall. The parts of the bearing in question are combined within a ring-shaped bearing element arranged in a plane that is perpendicular to the axis of the crosshead and the bearing element being arranged in an opening in the sidewall.
A cylinder device of this kind is described in U.S. Pat. No. 4,856,154. Here, the inner support device includes a series of support plungers, having hydrostatic bearing pockets, mounted on the crosshead along the cylinder gap which act on the inner circumference of the hollow cylinder on the cylinder gap side and apply the necessary individual forces there so as to generate the line force. When subjected to the opposite forces of the support plungers, the crosshead sags within the hollow cylinder without touching its inner circumference. For this reason, separation is maintained between the crosshead and this inner circumference all around. The alignment of the hollow cylinder is not affected or is only slightly affected by the line force in the cylinder gap. The sagging crosshead, which is subject to a line load due to the line force and is supported at its ends, provides the deformation required to apply counterload to the line load along the cylinder gap.
The type of support device used is independent of the invention. In the case of the cylinder device per U.S. Pat. No. 4,856,154, the support device includes the aforementioned plungers. However, it is also possible to use a longitudinal chamber in the shape of a semicylindrical pan filled with hydraulic fluid as described in German Patent No. PS 10 26 609. Magnetic or mechanical support devices are also feasible.
In all instances, the crosshead sags as described above, and as a result the ends of the crosshead that protrude from the hollow cylinder become inclined. In the known embodiment, these ends are supported in static outer bearings which are generally arranged in the sidewalls of a cylinder housing or in calender rockers and have spherical parts to prevent jamming which allow the crosshead to sag and transfer the cylinder forces to the machine housing.
The load applied to an individual pair of spherical parts at one end of the crosshead on the order of magnitude of 100 t. As the degree of deflection of the crosshead changes, the position of the spherical parts relative to one another changes due to the substantial load and the corresponding friction, and as a result substantial tilting forces are transferred from the bearing to the machine housing. It is therefore very important that a static bearing be used in which a given bearing does not turn relative to its counterpart during operation, but rather merely shifts slightly towards its counterpart in the plane of action when a change in deflection occurs. In this case the friction problem is particularly severe, as the break-away moment must be overcome.
U.S. Pat. No. 4,856,154 also makes reference to the space limitations to which the cylinders in question are subject: The bearing at the end of the crosshead must not project beyond the diameter of the hollow cylinder, otherwise it will come into conflict with the bearing of the adjacent cylinder. Therefore any embodiment of a cylinder of this kind must be designed so that it is radially as compact as possible.
In the case of the embodiment per German Auslegeschrift No. As 22 54 392, which is in other respects similar to U.S. Pat. No. 4,856,154, the friction is limited to the spherical parts, as movement only occurs there. This embodiment has inner throw, i.e. the hollow cylinder as a whole can move in a transverse direction relative to the crosshead. Cylinder adjustment movements are carried out by the inner support device, i.e. inside the cylinder. The bearings on the ends of the crosshead only have to absorb the deflection-related changes in angle, and do not have to be shifted as a whole in the plane of action when adjustment movements are carried out.
Bearing-centered cylinders are also used, and have rotatable bearings at the ends of the hollow cylinder via which the crosshead is supported. In this case the crosshead cannot move in a transverse direction relative to the crosshead, and therefore adjustment movements cannot be made inside the cylinder itself; instead, the cylinder as a whole must be shifted, along with its crosshead. In the case of these cylinders, adjustment movements are carried out by plunger/cylinder units which act on the end of the crosshead, are arranged in the cylinder housing, and act on the ends of the crosshead. The ends of the crosshead move along guideways which are parallel to the plane of action of the cylinder or in the cylinder housing. Due to the substantial amount of friction on the spherical parts that are also present in this case, load is applied to the guideways and results in frictional forces that make it difficult to precisely control the line force in the cylinder gap. The spherical surfaces in the bearings of the crosshead are used to absorb the alignment errors of the end of the crosshead that occur when the crosshead sags. Particularly in the case of tempered cylinders, the crosshead, which may be as much as 10 meters in length, undergoes thermal-related changes in length that cause the crosshead to shift in its longitudinal direction relative to the sidewalls of the cylinder housing, which are unaffected by the thermal elongation. Particularly in the case of heated cylinders, in which the crosshead also increases in temperature in its stationary state, the ends of the cylinders can shift by a significant amount. In the case of a 10-meter-long cylinder, a temperature difference of 100 degrees [C] can result in a shift of more than one centimeter, which must be absorbed by the outer bearings, and in this respect friction also arises at full load.
There remains a need therefore, in the case of a cylinder of the type described, to eliminate the problems associated with the high level of friction on the outer bearings while preserving the desired radially compact design.
SUMMARY OF THE INVENTION
The present invention provides for a cylinder device for processing continuous material strips having a deflection-controllable cylinder that includes a hollow cylinder rotating around its axis and which forms the working cylinder circumference. It is traversed lengthwise by a non-rotatable crosshead, clearance being maintained between the crosshead around the entire inner circumference of the hollow cylinder, and has an inner support device which is mounted on the crosshead and which acts on the inner circumference of the hollow cylinder. It also has outer bearings, which support the ends of the crosshead at outer sidewalls and which have cooperating spherical surfaces for absorbing the deflection of the crosshead, one of which is attached to the crosshead and the other to the respective sidewall. The parts of the bearing in question are combined within a ring-shaped bearing element arranged in a plane that is perpendicular to the axis of the crosshead and the bearing element is arranged in an opening in the sidewall. The given end of the crosshead extends through the ring-shaped bearing element and has a shoulder in the area of the bearing element that supports the single constructional unit formed by t
Butler Marc W.
Eduard Ku
Hughes S. Thomas
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