Winding – tensioning – or guiding – Convolute winding of material – Pressure element against coil
Reexamination Certificate
1999-06-08
2001-02-13
Nguyen, John Q. (Department: 3653)
Winding, tensioning, or guiding
Convolute winding of material
Pressure element against coil
Reexamination Certificate
active
06186438
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for positioning a smoothing roll which is mounted so as to be displaceable by means of a cantilever arm against the reeling mandrel of a strip coiler and to be adjustable particularly with a roll changing head against the reeling mandrel with the use of force application means.
2. Description of the Related Art
When coiling thin strips, particularly aluminum strips, it is known in the art to place a smoothing roll during the entire coiling process against the reeling mandrel or on the strip coiler in order to prevent air inclusions and strip defects, so called couch defects.
Because of jumps of the roll due to a diameter increase at the strip beginning, the so-called layer jump, the roll rotates unsteadily and hammer-like vibrations of the entire roll arm occur. In the past, it was not possible to eliminate this disadvantageous phenomenon even by using springs and dampers.
DE 33 18 031 A1 discloses a method and an apparatus for controlling the pressure rollers of a strip coiler influenced by pressure medium-operated cylinders. In accordance with this known method, in which the pressure rollers serve to introduce and press the first and last strip layers against the reeling mandrel or the previously wound strip layers, the strip beginning of the entering strip is observed and monitored without contact during the formation of the first winding and its respective position is utilized for positioning the pressure rollers.
In the apparatus for carrying out this known method, optical sensors are provided for the contactless monitoring of the strip beginning and an optical sensor is arranged immediately following each pressure roller as seen in the travel direction. The method and the apparatus require complicated mechanical and control-technological elements, so that, particularly when a diameter change of each strip layer occurs in the area of the strip beginning, the generation of markings due to mass inertia of the pressure rollers on the strip surface are avoided. For this purpose, the pressure rollers are controlled in such a way that they are moved back each time by a distance corresponding to the strip thickness before the strip beginning which causes the diameter jump passes the rollers. The reeling mandrel is coupled to a pulse generator which interacts with a pulse counter which starts to operate after a contact of the strip beginning at the reeling mandrels without slip has been achieved. It has also been proposed to observe and monitor without contact the strip beginning of the entering strip when the first winding is formed and to utilize the respective position for positioning the pressure rollers.
EP 0 391 135 A2 discloses a method of reeling strip in reeling plants. Using the method for controlling the pressure roller adjustment of a strip coiler which has become known under the name step control, it is possible to coil even strips on the reeling mandrel without damage. For this purpose, it is proposed that the pressure rollers move the strip as closely as possible to the reeling mandrel without, however, applying pressure forces against the reeling mandrel, or that only the last pressure roller in the entry direction of the strip moves the strip against the reeling mandrel, while the remaining pressure rollers move the strip as closely as possible to the reeling mandrel without exerting any pressure forces against the strip or the reeling mandrel. The contact of the strip against the reeling mandrel without slip is achieved by a position-controlled spreading of the mandrel segments.
SUMMARY OF THE INVENTION
Therefore, starting from the prior art discussed above, it is the primary object of the present invention to provide a smoothing roll unit for a strip coiler which is of particularly simple construction and operates with high vibration damping, wherein the smoothing roll unit is suitable to be mounted without problems at the exit side of a rolling train for thin strips and particularly aluminum strips, and the unit can particularly be used for retrofitting such a rolling train.
In accordance with the present invention, the roll change head includes a swivel arm which can be swivelled in a joint and is drivable to carry out a swivelling motion, wherein a steel roll is mounted at the free end of the swivel arm in a bearing, and an adjusting arm supporting the smoothing roll is mounted at the free end of the swivel arm, wherein the adjusting arm includes a force-controllable adjusting system for adjusting the smoothing roll against the strip coiler or the outer tube surface thereof, wherein the force application means for displacing the cantilever arm is a distance-controllable adjusting unit.
In the construction according to the present invention, the smoothing roll unit is supported through an oscillating crank system preferably on the axis of the steel roller. A support of the oscillating crank and, thus, of the smoothing roller is realized by a support at a pressure-controlled hydraulic cylinder. This ensures a targeted contact force regulation of the smoothing roller.
In accordance with further developments of the invention, the distance-controllable adjusting system includes at least one hydraulic cylinder and especially pulsation dampers, for example, bladder-type pressure accumulators or bladder-type accumulators, are arranged in the area of the connections of the hydraulic force application means on the side of the piston and piston rods, wherein the pulsation dampers are arranged as closely as possible next to the hydraulic cylinders.
In accordance with a useful further development, the bladder pressure of the pulsation dampers is preferably adjusted to a fixed value while narrowing the pressure range. Consequently, since the natural oscillation frequency of the pulsation dampers is far outside of the oscillation frequency of the oscillation crank supporting the smoothing roller, a complicated regulating system for the oscillation damping of the pulsation damper is not necessary.
The support of the smoothing roller or the oscillation crank support thereof at a pressure-controlled hydraulic cylinders ensures a targeted contact force regulation, while commercially available pulsation dampers are used at the cylinder supply lines at the side of the piston and piston rod for compensating and damping the jump at the strip beginning.
In accordance with the invention, the adjustment of the cantilever arm is effected through distance regulation, particularly in accordance with the build-up of the coil whose diameter increases. Instead of using force-controlled hydraulic cylinders, the force-controlled adjustment of the oscillation crank with smoothing roller could also be effected by pneumatic cylinders or another spring-type damping system.
In accordance with another advantageous feature, the masses of the smoothing roller system which are not spring-supported can be reduced by about 50% by a targeted selection of the material, i.e., a change from previously steel to aluminum. This ensures a significantly better adherence of the smoothing roller on the coil which is being coiled up.
In accordance with another advantageous further development of the invention, the smoothing roller may be formed by a tubular casing of light metal, for example, AlCuMgPb, and may be surrounded by a lining of highly resistant synthetic material.
As a result of the configuration of the smoothing roller unit according to the present invention, a significant increase of the service life of the roller lining can be achieved and the oscillations which build up during operation are simultaneously optimized in this manner.
In accordance with another feature, the individual proportional valves, pressure valves, distance valves, throttling valves and locking valves are mounted in accordance with their function on valve blocks and the valve blocks are combined to form control columns and are arranged on a substructure.
In accordance with another advantageous feature, the force application means
Grell Jürgen
Hoppe Rainer
Zeppenfeld Josef
Friedrich Kueffner
Nguyen John Q.
SMS Schloemann--Siemag Aktiengesellschaft
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