Background Art In prior art the cutting groups of the present invention usually include substantially at least a shear for the rolled sections cutting, generally known as flying shear, to which a shifter is associated, which alternatively shifts the bar on two channels placed downstream the shear, in order to allow the cut crop-ends advancement stopping, generally by means of a tail-braking device of known art, and then the following discharge on an underlying cooling bed, also known as cooling plate.

These cutters generally include a couple of opposite rotating cutters, which are stopped in stand-by, and at the suitable time are made rotate substantially at the peripheral speed corresponding to the advancement speed of the rolled section to be cut + 0%/+10%.

This art, even if effective, allows a maximum speed which cannot be exceeded because of the high accelerations and decelerations which must be exerted on said rotating cutters.

For obviating this drawback, solutions with opposite blade cutters always in continuous rotation, with peripheral speed substantially equal to the bar advancement speed were studied, while the bar being rolled is made pass sideways of the rotating cutters, and when it needs the cutting, this is actioned by said shifter, shifting the bar route beneath the cutting cutters and vice-versa, or always on the same side or rather, making the bar pass from one side to the other of said shear

cutters. (For this purpose see IT-769668; Application 9027/65-DEMAG, filed in 1965 and granted in June 1967).

Also the solution of T-8397A/87 (Danieli), utilises said system and for a rational co-ordination it obviously provides the co-ordination of the shifter movement with respect to the cutters movement and in the specific case: the synchronization between the rotating cutters circumferential position and the shifter temporal side position, in the phase just previous to the cutting. All this being anyway obvious and necessary in order to allow a rational cutting, with no jamming or cutting errors.

The solution of making the cutters rotate continuously has the great advantage of working at high speeds and practically evenly with the bar advancement speed also up to 100 m/sec and over.

The present innovation substantially thought for a cutting group in which the cutters are continuously rotating as above and the bar is made pass at a suitable time beneath the cutters in continuous rotation for the cutting, just like in the solution proposed in said IT-769668 (Application 9027/65-DEMAG).

These cutting groups though, which adopt continuously rotating cutters, have the drawback of wasting or scrapping a bar crop-end at the beginning (bar head) and a bar crop-end at the end (bar tail), and anyway present errors in the exact positioning of the rolled section cutting point, particularly the cutting values being corresponding to a certain necessarily whole number of blade revolutions.

The main purpose of the present invention is that of making all the cut bars have the same length.

A further purpose of the present invention is that of obtaining the highest number of bars from the rolled section whole length.

In order to obtain the same bars length, adopting a constant speed of the cutting cutters, up to now it was necessary cutting the initial part of the rolled section head known as discard (which is wasted, that is, destined to scrapping), in a way that all the subsequent bars have the same length, finally having to scrap the rolled section

tail which remains after the last cutting generally because it is shorter than the bars cut up to that time.

For example, it should be considered that the standard lengths of the bars to be cut by the shear, are generally equal to"n x c", where"n"is the number of submultiples which can be obtained from a bar discharged on the cooling plate, and "c"is the length of the bars which make up the finished product bundle. The length of the bar discharged on the plate may vary according to the finished product multiples (e. g. with c=12 metres, the bars on plate may have a length of metres: 12,24,36,48,60 etc.).

In other words, in the present art, the cutters in continuous rotation for the rolled section cutting to measure use a cutters angular speed which is constant in time and: -the shifter movement is tightly bound to the cutters angular speed (IT-769668- application 9027/65-DEMAG); -otherwise the shifter movement is adjustable by synchronization means with respect to the cutters position in the phase just previous to the cutting (IT- 8397A/87-Danieli).

The present invention is neither directed to one nor to the other of these solutions.

Solutions for the head and tail cutting and shifter movement modalities are also disclosed in: FR-666433; DE-804056; GB-2075.899; FR-1.578587, where different solutions for the bar's head and tail cutting and co-ordination of the shear with the other rolled section and cut bars movement means are proposed.

Nevertheless, when using the cutters at a determined rotational speed, some errors on the first cutting due to the non-corresponding position of the cutters on the arrival of the rolled bars, which obviously with their respective heads are not always at the same distance one from the other, occur.

The cutting position error is anyway also enhanced on the bar last cutting, if, for avoiding problems of discharge on plate, some optimisation of the same bar cutting length is required.

Purpose of the invention: The purpose of the present innovation is that of obviating the aforementioned drawbacks and of substantially making possible: -a higher operational speed; -the avoidance of material wasting in the rolled section head and tail; -a greater functionality with minor stress for the mechanisms and a whole system simplification.

Essence of the invention: The problem is solved as claimed by a high speed cutting method for rolled sections in continuous advancement, of the type in which is substantially provided: -a flying shear for the rolled section cutting with always rotating cutters; -shifter means which guide the rolled section to be cut from a position sideways of said cutting rotating cutters, through said cutting cutters, for carrying out the cutting, and -sensing means of the rolled section to be cut; characterised in that -said sensor means of the rolled section to be cut include at least means for detecting its advancement speed"Vb"and its position"Pb"along the advancement line with respect to the cutting point; -computer means and means for changing the rotational speed of said cutters"Vr", with finding of the respective angular position"Pc", driven by said computer means are further provided, and in which: -said rolled section sensor means are connected to said computer means; -some programming means are further provided for forcing said rotating cutters to rotate at a higher or a minor"Vr"in function: -of said"Vb"rolled section advancement speed, -of the head position of the rolled section in advancement before being cut"Pb" and

-of the respective cutters"Pc"position so that: -said cutters are pre-arranged with acceleration or deceleration for carrying out said rolled section first cutting for obtaining bars at the desired exact length"nc", where"n"is a whole number and"c"is a bar standard length constant.

Advantageously said method and computer means are conceived in a way that: -in case the remaining rolled section tail length was minor than"c", said computer shall provide, at least, for reducing of a unit said value"n"of the pre-determined cutting length, in at least the penultimate bar, and this in order to make said last bar increase of an equal length.

Thus recovering tail bars which, being too short for allowing an affective braking would be scrapped with a respective reduction of the amount of bars obtainabie from the rolled section whole length, will be possible.

Therefore, in this way also the system performance is improved. The solution of the position control in closed virtual chain adopted by the high speed shear allows, instead, a cutting to measure length variation because the system synchronizes in position the rolling electric axis and the cutters rotation electric axis in real time.

Thus the shear is a cutting to measure system for rolled section made up of a shear in continuous rotation and of a known system for shifting the rolled material.

The shear being a machine made up of two or more cutters counter-rotating on two rotation axes parallel one to the other and driven in their movement by a known electric motor.

As in the known art, the cutting occurs by a displacement orthogonal to the rolling axis, the shifting system brings the rolled section beneath the shear cutters for then displacing it away from the cutters interference once this has been cut.

By means of such a cutting cycle and a suitable control algorithm, the machine in object will thus be able to cut the rolled section at lengths which are pre- determined or calculated by means of cutting length optimisation algorithms. The high speed shear system according to the present innovation method is thus made up

of -a rotating shear with one or more cutters -a rolled section shifting system -an automation system which is made up of: -a micro-processor system which controls the cutting process; -an electric drive electrically connected to the finishing stand; -an electric drive mechanically connected to the shear cutters; -a pneumatical or electric or hydraulic drive connected to the shifting device; -a sensor of the rolled section position; -a sensor of the shear cutters angular position (encoder); -three sensors of the shifting device position, respectively: -one on a side -one on the other side; and -one at the centre in the middle position, corresponding to the cutting one; -a sensor of the rolling cylinders angular position (encoder); being provided that: -said micro-processor acquires in real time, by means of the sensors on the rolled section advancement line, the position of the same and controls and adjusts the shifting system position and the shear cutters rotation speed in order to perform the desired cutting series, obtaining bars of the required optimal lengths.

Such electronic system is thus able to effect a continuous synchronization between the head position of the rolled section in advancement on the rolling line ("Master" electric axis, that is master electric axis) and: -the shear cutters position and rotation speed. ("Slave"electric axis, that is slave electric axis).

-the material shifting device position ("Slave"electric axis) Advantageously the control principle between the"Master"axis and the"Slave" axes is based on that:

-The rolled section axis represents the control system"Master"axis while the cutters rotation axis is the"Slave"axis which must be synchronized with the "Master"axis.

-The synchronism point is the cutting point at the desired length of the rolled material on the"Master"axis and the cutters crossing for the"Slave"axis.

-The perfect synchronization occurs when once it has passed a cutting to measure length on the"Master"axis"nc" ; the"Slave"axis is at the cutters crossing with the speed necessary for correctly performing the cutting.

-The shear remaining in continuos rotation with a cutters peripheral speed (Vc) very close to that of the rolled section (Vb), whereby the cutting rotation is spaced by a certain number of idle revolutions.

-Such adjustment occurs by means of a control closed ring where, moment by moment, the shear cutters position in time is generated and corrected.

Advantageously it is provided that, in order to perform a perfect cutting to measure, the bar in advancement is displaced with a certain advance with respect to the cutting time, this being performed by the displacement device movement control; -being further provided that: -during the shear cutters revolution previous to the cutting one, such device brings the material on the axis of interference with the cutters before these may cross; -the two axes interference phase causes the bar cutting.

-once this has occurred, the shifter moves the rolled section into a non- interference position before the cutters complete their next revolution.

-once this has occurred, the shifter remains into an external position with respect to the cutting axis up to the next cutting cycle.

In an advantageous and possible variation, a shear with a couple of opposite cutters driven by respective electric motors, preferably without brushes"brushless", which are in electric axis one with the other.

Thus even higher cutting speeds may be reached, the mechanical gear mechanisms

being avoided.

Description of at least one embodiment form of the invention These and other advantages will result from the following description of an embodiment preferred form, with the aid of the enclosed drawings, whose execution details are not to be considered as limitative but are only given as examples.

Figure 1 is a schematic view of the rolling line section concerning the cutting plant according to the present invention.

Figure 1A is a block schematic view of the cutting shear group drive and control system according to the present invention and which thus is an integrant part of Figure 1.

Figures 2 and 3 are respective front and side schematic views of the shear controlled by the system according to the present invention.

Figure 4 shows the system operational scheme, that is the operational method according to the present invention, in its optimal version.

According to the figures, it may be noticed that"L"indicates the rolled section in advancement and the corresponding rolling line, while (Lb) indicates a bar cut in a first shifting line and (Lb') indicates the second shifting line for a next cut bar, being the cut bars shifted on one or on the other channel (25), by means of a shifter (23) placed upstream the always rotating opposite cutters (24).

Downstream the shear group (2), as in the known art, a tail-braking device (bars braking device 5) and a movable multi-channel raceway (6) also of known art which has the function of receiving the bars, that after being stopped in their advancement are made fall onto an underlying cooling bed, also known as cooling plate, which provides for the transversally cut bars translation, before conveying them again in a movement longitudinal to the packing line also of known art and not shown, are provided.

The shifter (23) is controlled by a fluidynamical cylinder (234) and its movement is controlled by three position sensors:

-two end ones (231-233) for the corresponding shifting lines (Lb, Lb') and -a centre one (232) for detecting the moment of passage under the cutting cutters (24).

The cutters are driven by an electric motor (20) whose angular position parameters, and following rotational speed, are transmitted by an encoder (21), while the cutters crossing position is determined by a cutters crossing sensor (22).

The shifter control fluidynamical cylinder (234) is controlled and driven by the computer (7) controlled shifter drive control system (2340).

The computer (7) receives the rolled section advancement position and speed parameters, respectively from the encoder (11) which detects the rotational parameters of the finishing stand (1) rolling cylinders before the shear (2) and from the photocell (L1) which shows the advancing rolled section presence, starting from its coming head, and which thus allows, in function of the angular total route of the finishing stand rolling cylinders and their diameter (1-11) and, in function of the finishing stand distance with respect to the cutting point (232) of the shear (2) cutters (24) and/or of a rolled section head (L1) position sensor in relation to its distance form the cutting point, to know the exact moment in which the shifter (23) must be driven for reaching the cutting position (232) and this by a cutters (24) rotation speed slight acceleration or deceleration in function of the rotational parameters detected by the respective encoders (21) and of the cutters crossing position (cutting condition 22).

Obviously the parameters detected by the finishing stand (1) may also be detected by the bars pinch-roll (8) just upstream of the shear or also by a couple of rolls which copy the bar advancement speed (idle rolls provided with said encoder), nothing changing in the innovative system of the present patent.

According to the block scheme of Fig. 1A, which should be meant as integrated with Fig. 1, all is explained, being the respective electric means of known art for the finishing stand (1) and shear (2) drive indicated with their respective references

(100) and (200).

In the solution indicated the shear is controlled by a single motor (20) which by a known gear system transmits the same motion in a contrary, equal and symmetrical angular direction to one and the other cutters (24).

Advantageously and for reaching even higher speeds, two electric motors (preferably brushless), one for each blade (24) axis, and the same concept of "Master"electric axis (finishing stand motor or pinch-roll motor placed just upstream the shear), and"slave"electric axis but in this case for both motors of the two cutters which in such case would be driven in an absolutely alike way, are used.

Thus the shear eliminates the need of any type of gearing, notoriously noisy and highly limitative for reaching high speeds, being always able to use the cutters (22) crossing sensor and also making possible, thanks to the computing speed of the present processors, to make in operating time corrections of the speed and then of one and the other blade position for obtaining the optimal cutting conditions, which would not otherwise be possible by using the mechanical transmission rigid restrains between the angular position of one and the other cutters.

Figure 4 shows the operational method which results very explanatory.