Surface cutting apparatus for hotrolled steel products

Abstract: The present invention relates to a surface cutting apparatus for hot-rolled steel products for cutting the top and bottom surfaces of a hot-rolled steel product continuously or intermittently by passing said steel product between a pair of rotary drums (55a,55b) rotating in the direction reverse to each other, said apparatus having chip discharge means (57) for discharging chips, which are produced by the cutting of the hot-rolled steel product by using said rotary drums, for each rotary drum.

Description: TECHNICAL FIELD The present invention relates to an apparatus according to the preamble of claim 1. Such an apparatus is known from EP 0 705 653 B1. In EP 0 705 653 B1, a metal product is passed between a lower scalping cutter and a back roller whereby the entirety of the bottom surface of said product is planarly cut be means of the lower scalping cutter. After the cutting of said bottom surface has been completed, the metal product is fed through two groups of feed rollers and passes then between an upper scalping cutter and a back roller, whereby the entirety of the top surface is planarly cut by means of an upper scalping cutter. In the apparatus disclosed in EP 0 705 653 B1, there is a risk that the cutting edges of the rotary drum might come into contact with the back roller, if the sheet is broken due to excessive cutting, which might be caused by damage to the cutting edges, operation error of the cutting apparatus and/or due to excessive pressing against the sheet. It is an objective of the present invention to provide an apparatus which solves the above-identified problem. As a solution to the objective, the present invention provides an apparatus as defined in new claim 1. Preferred embodiments of the present invention are set out in the dependent claim. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a configuration of the apparatus in accordance with the present invention, which can prevent the breakage of cutting edge and can recognize the gap between drums; Fig. 2 is a view showing another configuration of the apparatus in accordance with the present invention, which can prevent the breakage of cutting edge and can recognize the gap between drums; Fig. 3 is a view showing still another configuration of the apparatus in accordance with the present invention, which can measure the wear amount of cutting edge; Fig. 4 is a view showing an example in which measuring means are disposed on the upside and downside of rotary drum; Fig. 5 is a view showing another example of cutting apparatus in accordance with the present invention; Fig. 6 is a chart showing a specific procedure carried out when zero adjustment is made; The following is a description of a case where excessive cutting caused by the damage to cutting edge especially by operation error of the cutting apparatus and the excessive pressing against the sheet, which is an object to be cut, is avoided by using the means described in claim 1 and 2. In an apparatus having a sheet cutting rotary drum such as a milling cutter and grinding wheel, the outside diameter of the drum measured off-line is inputted to a computer by the operator, and the rotary drums are moved vertically based on the inputted information to adjust the position, by which a predetermined pressing amount is given to the cutting edge or grinding stone (specifically, the level of cutting edge or grinding stone face of the rotary drum is made to coincide with the level of sheet surface, that is, so-called zero adjustment is made, and then the rotary drum is moved from this state so as to obtain a predetermined working allowance). In the state in which the rotary drum is being rotated at a high speed for cutting, the position of cutting edge or grinding stone face of the rotary drum cannot be checked, so that exact zero adjustment cannot be made. Therefore, the working allowance of sheet exceeds the allowable range, or inversely the target working allowance cannot be obtained because the wear of cutting edge or grinding stone is higher than expected, so that working must be performed again. In particular, if the sheet is broken by the rotary drums because of the error of input to computer by the operator (for example, error of setting of rotary drum diameter) or the failure of a servo valve etc. of the cylinder for vertical movement, the cutting edges or grinding stones of the rotary drum are brought into contact with each other, resulting in an accident of damage to rotary drum. According to the present invention, the apparatus, in which a sheet is passed between a pair of rotary drums rotating in the direction reverse to each other and the top and bottom surfaces thereof is cut continuously or intermittently, is configured so that a disk for recognizing gap between drums having a larger diameter than that of the rotary drum is arranged at both ends or at one end of at least one rotary drum. This drum is brought into contact with the disk of the other rotary drum, and zero adjustment is made with this state being a reference. Thereby, the error of working amount caused by excessive pressing of rotary drum can be decreased greatly. Also, even if there is an input error of disk outside diameter, the load becomes excessive by the contact between disks, so that the input error can be recognized in the screw down system before the sheet is cut. In the case where a measuring means (non-contact type distance meter, eddy-current type sensor, etc.) which can find the wear amount (outside diameter of cutting edge on rotary drum) of rotary drum is provided in place of the disk, even if a wear of cutting edge or grinding stone is produced by the cutting of sheet, the rotary drums can be moved vertically on the line exactly by the wear amount (however, the speed of rotary drum is low). Therefore, more precise working can be performed than following the planned allowance. As the measuring means, an eddy-current type sensor, a laser type distance sensor, etc. can be used. The eddy-current type sensor measures a distance by detecting the current value changing according to the distance between the measuring means and the ferrous cutting edge by using eddy current. The laser type distance sensor measures a distance by detecting a reflected wave of laser beam irradiated on the cutting edge or grinding stone face by using laser beam. At the outer periphery of rotary drum, cutting edges or grinding stones are arranged in accordance with the sheet to be cut. For example, when scratches or dents of hot-rolled steel, projections of steel product joint portion, etc. are treated, a milling cutter cutting edge is used. When pushing flaws of cold-rolled steel, oscillation marks of hot-rolled steel, slight dents, etc. are treated, a grinding stone is used. Fig. 1 shows a configuration of the cutting apparatus in accordance with the present invention. In this figure, reference numerals 38a and 38b denote rotary drums arranged so as to cut the top and bottom surfaces of the sheet S 1 , S 2 continuously or intermittently by holding the sheet therebetween (a rotary drum can be used, for example, which is configured so that a plurality of disks having cutting edges at the outer periphery thereof are arranged along the rotating shaft of the drum and the positions of cutting edges on the adjacent disks are shifted alternately.), 39a and 39b denote disks for recognizing gap between drums shown in the example in which the disk is arranged at both ends of the rotary drum 38a, 38b, 40 denotes a shaft case for containing a bearing rotatably supporting the rotary drum, 41 denotes a screw down cylinder, 42 denotes a housing, 43 denotes a spindle, 44 denotes a pinion stand, and 45 denotes an electric motor. In order to surface-cut a sheet with a predetermined allowance, the disks 39a and 39b are brought into contact with each other by moving the rotary drums 38a and 38b to find the vertical absolute positions of cutting edges of the rotary drums (zero adjustment). Subsequently, the rotary drums 38a and 38b are rotated to a predetermined speed, and the rotary drums 38a and 38b are moved from that position to the same level as that of the top and bottom surfaces of the sheet S (S 1 , S 2 ) respectively, and then the movement of the rotary drums 38a and 38b is stopped at the point of time when the level such that the predetermined cutting allowance can be obtained is reached. The sheet 1 passing between the pair of rotary drums is cut by the cutting edge or grinding stone at the outer periphery of the rotary drum. Although there is fear of too large allowance caused, for example, by the setting error of initial position of the rotary drum 38a, 38b, excessive cutting or grinding of sheet can be prevented by bringing the disks 39a and 39b installed at the end of the rotary drums 38a and 38b into contact with each other in the state of maximum cutting allowance. In the present invention, as shown in Fig. 2, the disk 39a, 39b may be installed only at one end of the rotary drum 38a, 38b. Also, in place of the disk 39a, 39b, as shown in Figs. 3 and 4, several measuring means 4 6 may be arranged along the axial direction of at least one rotary drum. Fig. 3 shows an example in which the measuring means 46 are arranged on the upside only, while Fig. 4 shows an example in which the measuring means are arranged on both the upside and downside. It is best that the measuring means 46 be arranged on the upside of the rotary drum, but they may be arranged on both the upside and downside, or they may be arranged on the downside only. The measuring means on the downside is required to strictly take waterproof measures when cooling water is used for cutting or grinding and dustproof measures against chips as compared with the measuring means on the upside. By making zero adjustment by grasping the wearing state of cutting edge or grinding stone at the outer periphery of rotary drum using the measuring means 46, excessive cutting or grinding of sheet can be avoided. By disposing a cylinder on the measuring means 46 so that the measuring means can move close to or apart from the rotary drum, an accident of contacting the measuring means 46 with the rotary drum 38a caused when the rotary drum is moved can be prevented. Also, the measuring means 46 may be constructed so as to be capable of moving in the width direction of sheet S. Fig. 5 shows another example of apparatus in accordance with the present invention. Although the disk 39a, 39b, which is provided only on one side of the rotary drum 38a, 38b, shown in Fig. 2, has a larger diameter than that of the rotary drum, the diameter of the disk 39b is equal to or smaller than the diameter of the rotary drum 38b. Moreover, when the upper and lower rotary drums are brought close to each other by the screw down cylinders, the disk 39a and the disk 39b come in contact with each other before the rotary drum 38a and the rotary drum 38b come in contact with each other. In the case where the diameter of the disk 39a is different from that of the disk 39b, when the upper and lower rotary drums are rotated at the same rotational speed, a difference in circumferential speed occurs on the aforementioned disks, so that there is a possibility of damage to disk caused by frictional heat generation. Therefore; adjustment including zero adjustment should be made without rotating the drum. An example of specific procedure for zero adjustment is shown in Fig. 6. The gap between the upper and lower rotary drums is decreased with the command of zero adjustment start, and when a load is applied by hydraulic reduction, screw down is performed to the expected position (40 t load is applied when the disk width is 150 mm). After it is confirmed that the oil column value calculated from the outside diameter of rotary drum agrees with the actual oil column value, the cutting edge is rotated, and it is confirmed that the load deviation caused by disk eccentricity is not larger than ±2t. Thus, zero adjustment is completed. The wear amount at the tip end of rotary drum 38a, 38b is measured by the measuring means 46 as shown in Fig. 3, and the upper rotary drum 38a is moved downward and the lower rotary drum 38b is moved upward by the wear amount, by which a constant working amount can always be maintained. When the cutting edge or grinding stone wears eccentrically, uniform working sometimes cannot be performed in working sheets with a different width by simply moving the rotary drums up or down. Therefore, the rotary drum is replaced, or the disks subjected to heavy eccentric wear are replaced for the rotary drum which is configured so that disks having cutting edges etc. at the outer periphery thereof are combined. Such zero adjustment can be made not only on-line but also off-line. In either case, a trouble caused by input error does not occur. The absolute position of cutting edge or grinding stone can be detected only by vertically moving the rotary drums and bringing the disks into contact with each other, so that zero adjustment can be made easily, and hot-rolled steel products can always be cut in the allowable range (a predetermined cutting allowance), by which the sheets of stable quality can be supplied for a long period of time. Also, the cutting edges or grinding stones installed at the outer periphery of the rotary drum are not brought into contact with each other, so that the damage to the cutting edge or grinding stone can be prevented. In particular, by using a measuring means, the wear state (wear deviation) of cutting edge or grinding stone in the direction along the rotary drum can be detected, and the replacement of cutting edge etc. following the increase in deviation by wear can be performed automatically, so that labor saving can be achieved (claims 1 and 2).

Claims: A surface cutting apparatus for hot-rolled steel products for cutting the top and bottom surfaces of a hot-rolled steel product continuously or intermittently by passing said steel product between rotary drums (38a, 38b) rotating in the direction reverse to each other, characterized in that said rotary drums (38a, 38b) are arranged in pairs, that each rotary drum (38a, 38b) has at least one disk (39a, 39b), which has a diameter larger than that of said rotary drum (38a, 38b), at both ends or at one end of at least one rotary drum (38a, 38b), such that said disks (39a, 39b) are placed opposite to each other, for setting a gap between the rotary drums (38a, 38b) to a predetermined maximal cutting allowance. A surface cutting apparatus for hot-rolled steel products according to claim 1, wherein at least one rotary drum is provided with measuring means for measuring a wear amount at the tip end of said rotary drum to make a level adjustment of said rotary drum with respect to the hot-rolled steel product.

Inventors: AMAGASA TOSHIAKI, HAYASHI KANJI, HIRABAYASHI TAKESHI, ICHIKIZAKI TETSUO, ISOYAMA SHIGERU, KATSURA SHIGEFUMI, KURODA MOTOFUMI, NAKAGAWA TADASHI, NIKAIDO HIDEYUKI, SHIMIZU MASUTO, TAKAGI MITSUHIRO, TASHIRO SHOZO, YUKI ATSUSHI, AMAGASA, TOSHIAKI, HAYASHI, KANJI, HIRABAYASHI, TAKESHI, ICHIKIZAKI, TETSUO, ISOYAMA, SHIGERU, KATSURA, SHIGEFUMI, KURODA, MOTOFUMI, NAKAGAWA, TADASHI, NIKAIDO, HIDEYUKI, SHIMIZU, MASUTO, TAKAGI, MITSUHIRO, TASHIRO, SHOZO, YUKI, ATSUSHI, AMAGASA, Toshiaki, Kawasaki Steel Corporation, Hayashi, Kanji, Mitsubishi Jukogyo Kabushiki K., HIRABAYASHI, Takeshi, Kawasaki Steel Corporation, Ichikizaki, Tetsuo, Mitsubishi Jukogyo K. K., ISOYAMA, Shigeru, Kawasaki Steel Corporation, KATSURA, Shigefumi, Kawasaki Steel Corporation, Kuroda, Motofumi, Mitsubishi Jukogyo Kabushiki K., Nakagawa, Tadashi, Mitsubishi Jukogyo Kabushiki K., NIKAIDO, Hideyuki, Kawasaki Steel Corporation, SHIMIZU, Masuto, Kawasaki Steel Corporation, Takagi, Mitsuhiro, Mitsubishi Jukogyo Kabushiki K., Tashiro, Shozo, Mitsubishi Jukogyo Kabushiki K., YUKI, Atsushi, Kawasaki Steel Corporation
Applicants: JFE STEEL CORP, MITSUBISHI HEAVY IND LTD, JFE STEEL CORPORATION, MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1996
Main classification: B23C3
IPC codes: B23Q11, B21B15, B23C3