Measuring and testing – Dynamometers – Responsive to force
Reexamination Certificate
1998-03-31
2001-02-27
Fuller, Benjamin R. (Department: 2214)
Measuring and testing
Dynamometers
Responsive to force
Reexamination Certificate
active
06192765
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a planarity measuring roller constructed as a loop lifter which is adjustable relative to a rolled strip. The loop lifter includes a plurality of measuring zones located next to one another over the width of the rolled strip. Each measuring zone includes a rotatably mounted individual measuring roller which is pivotable in a clockwise direction and interacts with a force measuring device.
2. Description of the Related Art
A loop lifter of the above-described type was disclosed in DE-C2 40 31 666 as a control element for controlling the strip tension in strip rolling mills. The strip should preferably be without tension, i.e., a corresponding control variable should be zero. The loop lifter serving as a control element for controlling the strip tension is arranged, for example, at the exit side of a roll stand. The loop lifter has a plurality of measuring rockers arranged in pairs and distributed over the width of the loop lifter, wherein each measuring rocker has on one side a measuring roller facing the strip and a force measuring element on the other side.
In principle, the loop lifter or its individual measuring zones are constructed like a scale. Always two plate-shaped measuring rockers arranged parallel next to each other at a distance receive a measuring roller and have a pivot bearing screwed to a guide plate. Arranged additionally underneath the pivot bearing is a rotary axis for a height correction arm; this height correction arm is adjusted by several screws in such a way that the measuring roller is in a horizontal position. Each measuring roller is provided with two force measuring elements, wherein one force measuring element is provided at the measuring rocker and the other force measuring element is provided at a height correction arm. The height correction screws simultaneously constitute means for securing against lifting off. The configuration of the measuring zones of this known loop lifter make it necessary that the measuring roller has a degree of freedom in the horizontal plane. This is achieved by a cantilevered mounting by means of spherical roller bearings which are each arranged on an axis of the measuring rockers.
The two measuring rocker plates supporting each measuring roller have only a low stiffness in transverse direction, so that an appropriately large free space must remain between the individual measuring zones or measuring rocker plate pairs in order to prevent the plates from contacting each other. Because of the low stiffness of the measuring rocker plates and the cantilevered mounting of the measuring roller, there is the danger that the measuring rollers will be deflected out of the horizontal in the case of an eccentric load and that, as a result, the rolled strip is damaged by the raised roller edge on one side. When the measuring roller is inclined in this manner, there may also occur a contact with the measuring rocker which would lead to damage.
In this connection, especially endangered are the lubricant supply lines to the measuring roller bearings a damage of which would result in a failure of the bearing function. Finally, the friction resulting from a contact of the measuring rocker by the measuring roller would falsify the measurement. Furthermore, this loop lifter has many individual components which additionally must be mounted so as to be rotatable and, consequently, require a complicated lubrication. Also, the measuring rollers must not only be aligned in a time-consuming manner by means of many counterscrews and adjustment screws, but they must also be readjusted very frequently because they become loose or separated by the external loads and vibrations.
SUMMARY OF THE INVENTION
Therefore, it is the primary object of the present invention to provide a planarity measuring roller of the above-described type which does not have the disadvantages of the above-described loop lifter and is of particularly simple construction.
In accordance with the present invention, each measuring roller is mounted in a pivotable housing-like lever frame.
The lever frame in hollow box-type construction offers a very high stiffness which prevents inclined positions of the measuring rollers which are additionally preferably arranged on a continuous bearing axis. This makes it possible to arrange the individual lever frame segments of the loop lifter closely next to each other. As compared to the known embodiments, the planarity measuring roller or loop lifter according to the present invention can be of much flatter construction and can have a lighter weight and has significantly less mass especially in the area of the measuring roller. This makes it possible to achieve a substantially lower mass inertia moment which, particularly when manufacturing thin strips, results in significant advantages with respect to the strip tension control.
In accordance with a further development of the invention, the pivot points for the lever frames are provided on a shaft on which the force measuring devices are arranged. Consequently, the shaft, which may also be constructed as a hollow shaft in order to reduce the mass in this manner, has from the outset as many force measuring devices, for example, pressure pickups fastened by means of screws, as measuring zones or measuring rollers are desired. For pivoting the planarity measuring roller or the loop lifter into the strip travel path of the rolled strip, an adjusting cylinder is provided at least at one end of the shaft and the shaft is additionally equipped with a rotation sensor.
In accordance with a preferred embodiment of the invention, the pivot point of each lever frame, the point of rotation of the corresponding measuring roller and a force introduction point of the force measuring device arranged underneath of the pivot point of the lever frame form an approximately isosceles triangle. Since, in accordance with the present invention, these three points are connected to each other through a frame, wherein the connection between the points is subjected to tensile load or compressive load, it is possible to achieve an optimum stiffness and an optimum efficiency in force introduction due to the large lever arm from the point of rotation of the measuring roller to the rotary joint or pivot point of the lever frame.
It is possible to arrange the force measuring device perpendicularly of the connection line of the pivot point of the lever frame to the force introduction point and, thus, to transmit the strip tension in an advantageous manner to the force measuring device as a compressive force, and not as a tensile force as is the case in the known loop lifter. In addition, except for the bearings of the measuring rollers, only one joint is provided, namely in the area of the point of articulation or pivot point of the lever frame at the shaft, so that the unavoidable plays of the strip tension control due to finishing tolerances are much smaller than in conventional devices.
In accordance with an advantageous feature, a lift-off protection is provided outside of the triangle formed by the three points discussed above for each lever frame segment; this ensures that the lever frame can be pivoted in a clockwise direction, but not in a counter-clockwise direction. The liftoff protection may be formed, for example, by a bolt inserted into a throughopening of the lever frame and into an aligned bore in a projection of the shaft, wherein the screw head has on the side of the lever frame some free space, for example, 0.1-0.3 mm, from the lever frame when the lever frame is pivoted under the strip tension in the clockwise direction; alternatively, for example, a pretensioned screw may be provided for the same purpose, namely, to permit a movement in the clockwise direction and to prevent a movement in the counter-clockwise direction.
The modular construction of the planarity measuring rolling according to the present invention makes it possible, by loosening the lift-off protection which is freely accessible underneath the leve
Braun Martin
Kipping Matthias
Löhr Andreas
Sudau Peter
Tuschhoff Matthias
Fuller Benjamin R.
Kueffner Friedrich
SMS Schloemann--Siemag Aktiengesellschaft
Thompson Jewel V.
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