The present invention relates to a winding assembly for a rolling mill.
The invention has been developed with particular reference paid to rolling mills for rolling aluminium sheet. Rolling mills for aluminium produce sheets with a thickness ranging from 8 mm to 5 μm. Downstream of the rolling mill, the sheet is gathered in a coil by means of a winding assembly.
A winding assembly for a rolling mill for aluminium sheets generally comprises the following main components:
a winding spool, which turns about a first horizontal axis, wound on which is a coil formed by a continuous sheet of metal;
an ironing roll, which turns about a second axis parallel to the first axis;
an oscillating support, carrying the ironing roll and associated to actuator means, which are designed to push the ironing roll against the coil being formed;
a pass-line roll, which turns about a third axis parallel to the first axis and to the second axis; and
at least one deflector roll, which turns about a fourth axis parallel to the first, second, and third axes and is set between the pass-line roll and the ironing roll.
The pass-line roll is tangential to the plane of the sheet coming out of the rolling mill. In more traditional solutions, the pass-line roll is constituted by a simple roll. In more modern solutions, the pass-line roll is constituted by a flatness-measuring roll, designed to detect possible errors of flatness of the sheet immediately downstream of the rolling mill. The signals provided by the flatness-measuring roll are used for correcting the operating conditions of the rolling mill, according to a technique in itself known in the sector.
The deflector roll has the purpose of ensuring that the sheet will have a certain angle of winding with respect to the pass-line roll.
The ironing roll has the task of expelling the air between the sheet and the coil being formed. The air that remains trapped between successive layers of the coil produces major problems of flatness of the sheet and, given the same dimensions of the coil, entails a reduction in the useful weight of the coil.
The ironing roll is pressed against the coil in a point situated slightly further downstream with respect to the point of tangency between the sheet and the coil. Defined as angle of winding is the angle comprised between the radius of the coil passing through the point of tangency between the sheet and the coil and the radius of the coil passing through the point of contact between the ironing roll and the coil. The angle of winding is a very important process parameter for ensuring correct winding of the sheet on the coil.
Since the ironing roll is carried by an oscillating structure about a fixed axis, the angle of winding varies as a function of the diameter of the coil. For example, in a winding assembly of a known type, during formation of the coil, the angle of winding can vary from a minimum of 1.6° when the coil has a diameter of approximately 665 mm up to a value of 7.6° when the coil reaches dimensions in the region of 2000 mm.
This variation of the angle of winding creates considerable problems, amongst which the greater tendency to accumulate air between the layers of the coil as the diameter of the coil increases. Traditionally, formation of the coil is interrupted when, on account of the increase in the angle of winding, a regular winding of the sheet can no longer be ensured.
The object of the present invention is to provide a winding assembly for a rolling mill that will enable the aforesaid drawbacks to be overcome. In particular, the purpose of the invention is to provide a winding assembly that will enable control and adjustment of the angle of winding during formation of the coil.
According to the present invention, this object is achieved by a winding assembly having the characteristics forming the subject of claim 1.
The present invention will now he described in detail with reference to the attached drawings, which are provided purely by way of non-limiting example and in which:
With reference to
The rolling mill 10 has been illustrated in a purely schematic way merely to provide a framework for the present invention. The invention regards specifically the winding assembly 20, which can be combined with rolling mills of any type.
In
With reference in particular to
The winding assembly 20 comprises an ironing role 30, which turns about a second axis 32 parallel to the axis of rotation 26 of the spool 24. The ironing roll 30 is carried by an oscillating structure 34, which is articulated to the stationary base 28 about an axis 36 parallel to the axis of rotation 32 of the ironing roll 30.
With reference to
With reference to
The winding assembly 20 comprises a pass-line roll 48 carried by the stationary base 28 in such a way that it turns about a third axis 50 parallel to the first axis 26 and the second axis 30. In the example illustrated in the figures, the pass-line roll 48 is constituted by a flatness-measuring roll. This roll is in itself known and is typically constituted by a plurality of sections set side by side (
The winding assembly 20 comprises a deflector roll 52 set, with reference to the direction of advance of the sheet F, between the pass-line roll 48 and the ironing roll 30. The deflector roll 52 turns about a fourth axis 54 parallel to the axes 26, 32 and 50. The deflector roll 52 has the purpose of deflecting the sheet F downstream of the pass-line roll 48 so as to ensure that the sheet F will have an angle of winding with respect to the pass-line roll 48.
According to the present invention, the axis of rotation 54 of the deflector roll 52 is mobile parallel to itself, and the position of said axis is adjustable as a function of the diameter of the coil 22. The adjustment of the position of the axis 54 of the deflector roll 52 enables control and adjustment of the angle of winding.
Thanks to the present invention, the angle of winding is no longer an uncontrollable parameter depending only upon the geometry of the winding assembly but becomes a parameter adjustable by varying the position of the deflector roll.
The winding assembly according to the present invention could also be provided with two deflector rolls, set in series with respect to one another along the path of the sheet F. In this case, the deflector roll immediately adjacent to the pass-line roll 48, which turns about a fixed axis, would have the purpose of keeping the angle of winding of the sheet constant on the pass-line roll 48, whilst the deflector roll 52 immediately adjacent to the ironing roll 32 would be mobile for controlling the angle of winding.
In what follows, an adjustment mechanism will be described For adjusting the position of the deflector roll 52 during formation of the coil 22. It is understood, however, that the present invention is not limited to this particular adjustment mechanism, it being possible to use various other systems for adjusting the position of the deflector roll.
With reference to
Preferably fixed to one of the two slides 58 is a flange 62 carrying an electric motor 64, which drives the deflector roll 52 in rotation about the axis of rotation 54 by means of a belt transmission 66. The two slides 58 are fixed to one another by means of a cross-member 68 that is associated to an actuation device 70.
The actuation device 70 comprises an electric motor 72 numerically controlled by an electronic control unit 74, which, among other things, receives information regarding the diameter of the coil 22 being formed. The motor 72 is connected to two transmission devices 76 carried by a fixed beam 78. The two transmission devices 76 convert the rotary movement imparted by the motor 72 into a linear movement of respective output members 80 connected to the cross-member 68. The two transmission devices 76 are connected together by means of a shaft 82.
Preferably, the actuation device 70 is moreover provided with a stabilization mechanism designed to guarantee that the cross-member 68 moves remaining always parallel to itself. Said stabilization mechanism can be obtained by means of a pair of rack devices 86 including respective racks 87 fixed to the cross-member 68. The two rack devices 86 are provided with respective toothed gears that are fixed to one another by means of a tubular shaft 88 set coaxially on the outside with respect to the shaft 82 that connects the actuation devices 76 to one another.
In operation, the electronic control unit 74 controls the electric motor 72 as a function of the diameter of the coil 22. The actuation device 70 controls the movement of the deflector roll 72 in the direction indicated by the arrow 90 in
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Number | Date | Country | Kind |
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07425238.8 | Apr 2007 | EP | regional |