APPARATUS AND METHOD FOR CHANGING METAL MOLDS FOR PLATE THICKNESS REDUCING PRESSES

Abstract: An apparatus for changing metal molds for plate thickness reducing presses, comprising upper and lower metal mold receivers (28a, 28b) opposed vertically to each other with a transfer line provided therebetween, and capable of being moved toward and away from each other, a mold receiver guide rail (31) provided on the upper metal mold receiver and extending substantially horizontally in the widthwise direction of the transfer line, an upper metal mold (29a) which has rollers (33) therefor rollable along the mold receiver guide rail, and which is fixed to the upper metal mold receiver by these rollers, a fixing member (30) capable of securing the upper metal mold to the upper metal mold receiver, a lower metal mold (29b) placed on the lower metal mold receiver (28b), a fixing member (30) capable of securing the lower metal mold to the lower metal mold receiver, metal mold fastening members (38) opposed to side surfaces of the upper and lower metal molds and capable of being combined with the two metal molds, and a metal mold changing mechanism capable of moving one metal mold fastening member substantially horizontally in the widthwise direction of the transfer line.

Description: This invention relates to apparatus and method for changing dies for a plate reduction press machine. Prior art 1. Figs. 1 and 2 show an example of a conventional plate reduction press machine; the machine comprises a frame 1 installed at a predetermined location on a transfer line S, provided with guide columns 3 such that the material to be pressed 2 can be moved inside the frame 1, a lower die holder 4 fixed substantially horizontally at the lower ends of the guide columns 3, an upper die holder 5 connected to the guide columns 3 so that it can be freely raised and lowered in opposition to the lower die holder 4 across the transfer line S a crank shaft (not illustrated) located above the die holder 5, extending substantially horizontally in a direction orthogonal to the transfer line, and supported on the frame 1 by bearings on the non-eccentric portions, and a lower die 8 and an upper die 9 mounted on the lower die holder 4 and the upper die holder 5, respectively, facing each other, on opposite sides of the transfer line S. The lower die holder 4 is provided with a dovetail groove 10 extending in the direction of the transfer line, on the upper surface, and a lower slide plate 12 coupled with the dovetail groove 10 in a freely movable manner and the lower die 8 is mounted on the upper surface of the slide plate 12 and coupled to it by means of a cotter pin 11.The upper die holder 5 can move up and down with a reciprocating movement along the guide columns 3 when the crankshaft rotates, as the holder is supported and driven by an eccentric portion of the crankshaft. The holder is provided with a dovetail groove 13 extending in the direction of the transfer line, in its lower surface, and provided with an upper slide plate 15 engaging in a freely movable manner with the dovetail groove 13, and coupled to the upper die holder 5 by the cotter pin 14.At the center of the upper slide plate 15, a through-hole 17 is bored with a peripheral groove 17a, and the upper die 9 installed, on the lower surface of the lower die support holder 18 is provided with a flange 18a that can engage with the peripheral groove 17a of the through-hole 17 and is inserted through the top of the through-hole 17.The crank shaft is connected to the output shaft (not illustrated) of a motor through a universal coupling and a speed reduction gear, and when the motor operates, the upper die holder 5 moves towards and away from the transfer line S, so that the upper die 9 mounted on the die holder 5 via the lower die support holder 18, also moves towards and away from the lower die 8.When the material to be pressed 2 is pressed and formed in the direction of its thickness using the plate reduction press machine shown in Figs. 1 and 2, the motor is operated and the crankshaft is rotated. Then, the material to be pressed 2 is inserted from the upstream A side of the transfer line, into the gap between the upper die 9 and the lower die 8. The material to be pressed 2 moves from the upstream A side of the transfer line along the transfer line S towards the downstream Side B of the transfer line, while the material is pressed and shaped in the direction of its thickness by the upper die 9 that moves towards and away from the transfer line S according to the movement of the eccentric portion of the crank shaft.When the lower die 8 is to be replaced, the cotter pin 11 that locates the lower slide plate 12 in the lower die holder 4 is removed, the lower slide plate 12 is pulled out along the dovetail groove 10 of the lower die holder 4, the lower die 8 is moved out of the plate reduction press machine, the lower die 8 mounted on the lower die holder 4 is released from the lower die holder 4, and then the lower die 8 is lifted up by a hoist not illustrated and transferred to another predetermined site. Using the same hoist, a new lower die 8 is then lifted up, carried over the lower slide plate 12 and mounted there, and then the lower slide plate 12 is pushed into the center of the plate reduction press machine along the dovetail groove 10 of the lower die holder 4, and locked on the lower die holder 4 using the cotter pin 11.When the upper die 9 is to be replaced, the cotter pin 14 that locates the upper slide plate 15 to the upper die holder 5 is removed, the upper slide plate 15 is pulled out along the dovetail groove 13 of the upper die holder 5, and is moved out of the plate reduction press machine, the upper die support holder 18 incorporated in the upper slide plate 15 is lifted up by a hoist not illustrated and taken to another predetermined site, and after the upper die 9 is removed from the die support holder 18, a new upper die 9 is mounted on the upper die support holder 18, and then the die support holder 18 is lifted up by the hoist and carried above the upper slide plate 15, and after the holder 18 is positioned in the through-hole 17 of the upper slide plate 15, the slide plate 15 is pushed in along the dovetail groove 13 of the upper die holder 5, into the center of the plate reduction press machine, and then locked in the upper die holder 5 by the cotter pin 14.However, with the plate reduction press machine shown in Figs. 1 and 2, the wear of the lower and upper dies 8, 9 is so severe that each die 8 or 9 must be replaced frequently. Consequently, unless the dies are often replaced, the specified capacity of the plate reduction press machine, even if it has a high efficiency, cannot be achieved, and this is a problem. 2. Conventionally, a rough rolling mill is used to roll a slab. The slab to be rolled may be as short as 5m to 12m, and a plurality of rough rolling mills are required to roll the slab or the slab must be rolled backwards and forwards in a reversing rolling system, to obtain the predetermined thickness of the slab. In addition, it is planned to use a reduction press machine of which an example is shown in Fig. 3. The example shows a case in which cranks and connecting rods are used; the cranks 104 are connected to the dies 102 installed above and below the slab 101, through connecting rods 103, and the dies 102 are moved up and down to press on the slab. The slab 101 is moved by pinch rolls 106 and the transfer table 107. Recently, a continuous casting system has been introduced to produce a long slab, so it is necessary to move the slab continuously to a reduction press machine after it leaves the casting system. When a slab is rough rolled with a rough rolling mill, there is a minimum nip angle (about 17∞), and the permissible reduction Δt per rolling operation is about 50 mm. Reversing rolling cannot be applied because the slab is continuous, therefore to achieve a predetermined thickness, it is necessary to provide a plurality of rough rolling mills in series, or if one rolling machine is used, the diameter of the working rolls must be made much greater. However, such a rough rolling mill with large diameter rolls is difficult to design and manufacture because of its high cost, and furthermore rolls with a large diameter must rotate at a low speed so that the rolls cannot be cooled easily, which results in a short life for the rolls. When a reduction press machine with cranks and connecting rods is used, the slab must be continuously moved even during pressing, so the slab is moved by pulling it with pinch rolls. As a result, there is a large load on the pinch rolls, which makes the size of the entire system large. Consequently, there are many problems with vibration and cost.To solve these problems, the inventors of the present invention, invented and applied for a patent for the "Thickness reduction press machine" (unexamined Japanese patent application No.10-42328 see JP-A-11239832). This machine is shown in Fig. 4 and comprises dies 102 provided above and below the slab 101, a slider 108 provided for each die to give the die an up and down and backwards and forwards motion, and a drive system to drive these sliders. The aforementioned sliders are provided with a main unit 108a in which circular holes are bored with center lines at right angles to the direction of the slab, these circular holes with axes 109a engage with, cranks 109 (eccentric axes) with second axes 109b and a diameter less than the diameter of the holes, and the center lines of these axes are displaced from those of the holes. These cranks are rotated by the above-mentioned drive system.With this configuration, when the cranks are rotated, the axes of the circular holes are cranked around the center line of the second set of axes, and this transmits an upwards and downwards and backwards and forwards movement to the main unit 108a. Thereby, the slider 108 can press the dies and give a forward movement to the dies during pressing, so that the slab 101 is pushed forwards (in the direction of drawing the slab) during pressing, so enabling a continuous pressing operation. In addition, according to this invention, the slab 101 is pressed by dies 102 from both above and below, so a large rolling reduction can be attained.Although the aforementioned plate reduction press machine provides a large rolling reduction and can press a slab continuously, there is a proportionally severe wear on the upper and lower dies, possibly resulting in shorter intervals for replacing dies. As known in the prior art, there are die changing systems for reduction press machines, stentering machines, etc. However, even if any of the systems is adapted for use in a plate reduction press machine, there is the problem that excessive time and labor are spent in replacing dies. 3. Moreover, conventional reduction press machines such as slab presses that reduce the thickness of a slab, stentering presses that compress a slab laterally, or forging presses, incorporate dies that are constructed integrally. When a high-temperature material, e.g. a slab, is compressed using a thickness reduction press, the temperatures of the dies are not distributed evenly in the direction of breadth (lateral direction of the slab), so the dies may often deform or crack. In addition, the sides of the center portion of the dies wear more than both ends. Therefore, when the center portion wears by a predetermined amount, the dies must be replaced even if both ends have not worn so much. When the size of the dies is large, integral dies cannot be manufactured easily, and they also become expensive. SUMMARY OF THE INVENTION The present invention has been accomplished in the above-mentioned circumstances, with the objective of providing a die changing apparatus for a plate reduction press machine used in a hot rolling transfer line, which can replace dies efficiently, and a method for operating said apparatus. The above objective is achieved by an apparatus as defined in claim 1 and by a method as defined in claim 12. Preferred embodiments of the inventive apparatus are defined in the dependent subclaims 2-11. In the die changing apparatus according to the present invention, the upper die is fixed by means of the upper fixing device, on to the upper die support holder, and the lower die is fixed by the lower fixing device to the lower die support holder. In addition, when the upper and lower fixing devices are released, the upper and lower dies that are connected together by means of the die fastening members and are supported on the support holder guide rails by the die rollers, are moved in a direction perpendicular to the transfer line using the die changing mechanism. According to a preferred embodiment of the present invention, the upper and lower dies are connected together by the die fastening members in the condition that the upper and lower fixing devices are released and the external guide rails are located correctly opposite the support holder guide rails, and then with the dies suspended from the support guide rails by the die rollers, a moving member is connected to one of the die fastening members, through a connecting member, and the moving member is moved by the actuator of the die changing mechanism along the external guide rails, in the direction lateral to the transfer line. In this way, the upper and lower dies connected together are moved from the support holder guide rails to the external guide rails, and vice versa. According to another preferred embodiment of the present invention, the turntable is rotated to a location where the external guide rails of a predetermined die changing mechanism out of the plurality of die changing mechanisms are placed correctly opposite the support holder guide rails, the upper and lower dies to be replaced, whose upper and lower fixing devices are released, are connected together using the die fastening members, and after suspending the dies on the support holder guide rails by means of the dies rollers, a moving member is connected to a predetermined die fastening member by a connecting member, the moving member is moved along the external guide rails in the opposite direction to that of the transfer line, by means of the actuator of the die changing mechanism, thus the above-mentioned old upper and lower dies are moved from the support holder guide rails to the external guide rails of the predetermined die changing mechanism. At the same time, new upper and lower dies connected integrally with the die fastening members are placed on the external guide rails of another die changing mechanism, and the moving member is connected to the aforementioned die fastening member via a connecting member. After that, the turntable is rotated to the location where the external guide rails of the second die changing mechanism are opposite the support guide rails, the actuator of the second die changing mechanism is operated, and by moving the moving member towards the transfer line along the external guide rails, the new upper and lower dies are moved to the support holder guide rails, and after removing the die fastening member, the upper die is fixed by the upper fixing device, and the lower die is fixed by the lower fixing device In another preferred embodiment of the present invention, the cart is moved to a location where the external guide rails of one of the die changing mechanisms are correctly opposite the support holder guide rails, and after suspending the old upper and lower dies to be replaced, whose upper and lower fixing devices have been released, and coupling the dies together by means of the die fastening members, the moving member is connected to one of the die fastening members via the connecting member, and by moving the aforementioned moving member in the opposite direction to that of the transfer line along the external guide rails by means of the actuator of the die changing mechanism, the above-mentioned old upper and lower dies are transferred from the support holder guide rails to the external guide rails of the die changing mechanism. At the same time, new upper and lower dies connected together by the die fastening members are loaded on the external guide rails of another die changing mechanism, and the moving member is connected to the die fastening member by the connecting member. After that, the cart is moved to a location where the external guide rails of the changing mechanism are correctly opposite the support holder guide rails, and by operating the actuator of the die changing mechanism and moving the moving member towards the transfer line along the external guide rails, the above-mentioned new upper and lower dies are moved to the support holder guide rails, and after removing the die fastening member, the upper and lower dies are fixed by means of the upper and lower fixing devices, respectively. According to a further preferred embodiment of the present invention, the old upper and lower dies whose upper and lower fixing devices have been released, are coupled together using the die fastening members, and after suspending the dies on the support holder guide rails by means of the die rollers, one end of the pulling rope is attached to one of the die fastening members, and the other end is attached to the other die fastening member. After the above, the winch of the die changing mechanism is operated so that the pulling rope is reeled in the direction that causes the die rollers to move towards the rack, thereby the aforementioned old upper and lower dies are transferred to the rack, the upper and lower dies are replaced with the new upper and lower dies, and the dies are suspended from the die rollers. Then, the winch of the die changing mechanism is operated so that the pulling rope is reeled in the direction that causes the die rollers to move to the support guide rails, thus the above-mentioned new upper and lower dies are transferred to the support holder guide rails, and after removing the die fastening members, the upper and lower dies are fixed using the upper and lower fixing devices, respectively. In another preferred embodiment of the present invention, the old upper and lower dies to be replaced, whose upper and lower fixing devices have been released, are coupled together by means of the die fastening members, and after suspending the dies on the support holder guide rails by means of the die rollers, one end of the pulling rope is attached and fixed to one of the die fastening members, and the other end is attached and fixed to the other die fastening member. At the same time, new upper and lower dies joined together with the die fastening members are placed on the external guide rails on the rack on one side. Thereafter, the winch of the die changing mechanism is operated so that the pulling rope is reeled in the direction that causes the die rollers to move to the rack on the other side, thereby transferring the aforementioned old upper and lower dies to the rack on the other side. Then, one end of the pulling rope disconnected from the die fastening members that connect the old upper and lower dies, is attached and fixed to one of the die fastening members that connect new upper and lower dies, and the other end of the rope is attached and fixed to the other die fastening member, and by operating the winch of the die changing mechanism so that the pulling rope is reeled in the direction that causes the die rollers of the new upper die to move to the support holder guide rails, thereby transferring the above-mentioned new upper and lower dies to the support holder guide rails, and after removing the die fastening members, the upper and lower dies are fixed by means of the upper and lower fixing tools, respectively. According to a preferred embodiment of the present invention press dies which are used in the inventive apparatus and can make the distribution of temperatures on the slab uniform, in which it is possible to replace only the center portions of the dies because these portions wear sooner than the other portions, and which can be manufactured easily with a lower manufacturing cost, are provided. In a preferred embodiment of the present invention dies comprising an upper die and a lower die such that the material being pressed is positioned between the dies, with parallel surfaces and sloping surfaces on opposite sides of the material to be pressed, in which the press dies comprises a plurality of segments split in the lateral direction of the material being pressed. When dies are comprised of segments divided in the lateral direction, the temperature distribution of each segment of the dies is made uniform, so that the occurrence of defects such as cracks and deformations is reduced drastically. When a center portion of the dies wears, it is possible to replace only the central segments of the dies. Dies split into segments can be manufactured more easily than dies consisting of large blocks, so the cost is lower. According to another preferred embodiment of the invention, the surface of one of the above-mentioned segments of the dies, in contact with the surface of an adjacent segment is set at an angle to the direction of movement of the material being pressed. By setting the surface of a segment in contact with an adjacent segment, at an angle to the direction of movement of the material being pressed (longitudinal direction), stripes produced on the material being pressed by the split segments during drawing can be reduced in size. According to another preferred embodiment of the invention a passage for cooling water, inside the aforementioned split segments of the dies is provided. The life of split segments of dies can be prolonged by cooling by means of cooling water passages, constructed inside the segments. According to a further embodiment of the present invention, a plurality of grooves are formed in at least one of the parallel or sloping surfaces of the segments of the dies. Slippage between the segments of the dies and the material being pressed can be reduced by means of grooves formed in either or both the parallel or sloping surfaces of the segments of the dies, in contact with the material being pressed. In addition, the flow of the material being pressed can be regulated better when the material is pressed and formed to change. According to another preferred embodiment of the invention apparatus, a plurality of raised parts are formed on at least one of the parallel or sloping surfaces of the above-mentioned segments of the dies. Slippage between the segments of the dies and the material being pressed can be reduced, by forming raised parts on either or both the parallel or sloping surfaces of the segments of the dies, which are in contact with the material being pressed. Other objects and advantages of the present invention will be clarified in the following paragraphs and by referring to the attached drawings. BRIEF DESCRIPTION OF THE DRAWING Fig. 1 is a schematic view of an example of a conventional plate reduction press machine. Fig. 2 is a section view of Fig. 1 along the line XI-XI. Fig. 3 shows a schematic arrangement of a conventional plate reduction press. Fig. 4 is a schematic arrangement of a plate reduction press of an unexamined Japanese patent application. Fig. 5 is a schematic view showing the main reduction press machine provided with a die changing apparatus according to the present invention. Fig. 6 is an enlarged view of parts of the dies related to Fig. 5. Fig. 7 is a schematic view showing the die changing mechanism of the first embodiment of the die changing apparatus according to the present invention. Fig. 8 is a section view of Fig. 7 along the line IV - IV. Fig. 9 is a plan layout view of the die changing mechanism shown in Fig. 7. Fig. 10 is a schematic view showing the die changing mechanism of the second embodiment of the die changing apparatus according to the present invention. Fig. 11 is a section view of Fig. 10 along the line VII-VII. Fig. 12 is a plan layout view of the die changing mechanism shown in Fig. 10. Fig. 13 is a schematic view showing the die changing mechanism of the third embodiment of the die changing apparatus according to the present invention. Fig. 14 is a configuration of a reduction press using the split dies according to the present invention. Fig. 15 is a view of Fig. 19 along the line X-X, showing the first embodiment of the split dies. Fig. 16 is a view showing the arrangement of a cooling water passage, constructed in the split dies. Fig. 17 is a view showing the condition of the split dies when grooves or raised parts are formed in the parallel or sloping surfaces. Fig. 18 is a view of Fig. 19 along the line X-X, showing the second embodiment of the split dies. DESCRIPTION OF PREFERRED EMBODIMENTS The embodiments of the present invention are described in the following paragraphs, referring to the drawings. (First embodiment) Figs. 5 through 9 show the first embodiment of the apparatus according to the present invention. A plate reduction press machine 20 comprises a housing 21 erected at a predetermined location in a hot rolling transfer line S for the purpose of pressing a material 2, an upper journal box 23a and a lower journal box 23b housed in window portions 22 of the housing 21, facing each other across the transfer line S, upper and lower crank shafts 24a, 24b extended substantially horizontally in the lateral direction of the transfer line S, whose non-eccentric portions are supported by bearings (not illustrated) in the upper journal box 23a and the lower journal box 23b, respectively, rods 25a, 25b supported by bearings on the eccentric portions of the aforementioned crank shafts 24a, 24b at the extreme ends thereof while being rotated, above and below the transfer line S, respectively, an upper die holder 27a and a lower die holder 27b connected to the ends of the rods 25a, 25b through brackets 26a, 26b, an upper die 29a mounted on the above-mentioned die holder 27a by an upper die support holder 28a, and a lower die 29b mounted on the lower die holder 27b by a lower die support holder 28b. The crank shafts 24a, 24b are connected to the output shaft (not illustrated) of a motor, via a universal coupling and a speed reduction gear which are not illustrated, and when the motor is operated, the upper and lower dies 29a, 29b move towards and away from each other in synchronism with the transfer line S. The upper die holder 27a and the lower die holder 27b are housed so they are free to slide in the window portion 22 of the housing 21, and are provided with hydraulic cylinders 30 arranged to extend the tips of piston rods through the upper and lower die support holders 28a, 28b. The upper die support holder 28a is fixed on the lower surface of the upper die holder 27a and provided with support holder guide rails 31 that are fixed on the bottom surface of the upper die holder 27a, the rails face each other with a predetermined spacing in the direction of the transfer line, extend in the lateral direction of the transfer line S parallel to each other, and each is shaped to be convex at the top, on the lower surfaces. The lower die support holder 28b is fixed on the upper surface of the lower die holder 27b, and is provided with a square groove 32 extending in the lateral direction of the transfer line S, as wide as appropriate for the length in the longitudinal direction of the transfer line of the lower die 29b, on the upper surface of the lower die holder. The upper die 29a is provided with a plurality of die rollers 33 that are mounted on and protrude outwards from both ends of the upper surface in the direction of the transfer line, and arranged in rows to be capable of rolling along the aforementioned support holder guide rails, and a dovetail groove 34a in the center portion of the upper surface, penetrating in the direction lateral to the transfer line. This dovetail groove 34a is shaped to allow the insertion of and engagement with the tip of the piston rod of the above-mentioned hydraulic cylinder 30 when the upper die 29a is mounted on the upper die support holder 28a, and when hydraulic pressure is applied to the hydraulic chamber at the rod end of the hydraulic cylinder 30, the top surface of the dovetail groove 34a is pressed into close contact with the upper die support holder 28a by the aforementioned tip of the piston rod so that the upper die 29a is fixed to the upper die support holder 28a. The length of the lower die 29b in the longitudinal direction of the transfer line is such that the die can move along the dovetail groove 32 of the lower die support holder 28b described above, and the lower die is provided with a dovetail groove 34b in the center portion of the lower surface, penetrating in the lateral direction of the transfer line S. This dovetail groove 34b receives and engages with the tip of the piston rod of the above-mentioned hydraulic cylinder 30 when the lower die 39b is mounted on the lower die support holder 38b, and the tip of the piston rod presses the bottom surface of the groove 34b into close contact with the lower die support holder 28b when hydraulic pressure is applied to the fluid chamber at the rod end of the hydraulic cylinder 30, and the lower die 29b is fixed on the lower die support holder 28b. The upper die 29a and the lower die 29b are provided with flat forming surfaces 35a, 35b gradually tapering towards the transfer line S from the upstream A side of the transfer line to the downstream Side B of the line, and flat forming surfaces 36a, 36b continuing from these forming surfaces 35a, 35b, parallel to each other on opposite sides of the transfer line S. The width of each die 29a or 29b is determined by the plate width (about 2,000 mm or more) of the material being pressed. A position adjusting screw 37 is provided at the top of the housing 21, which drives the upper journal box 23a towards and away from the transfer line S, and by rotating this position adjusting screw 37, the upper die 29a is raised and lowered via the crank shaft 24a, the rods 25a, the upper die support holder 27a, etc., thereby the space between the upper die 29a and the lower die 29b, that is, the reduction caused by pressing the material being pressed, is adjusted. P15 The die fastening member 38 is provided to fasten the upper die 29a and the lower die 29b to form a single unit when replacing the upper and lower dies 29a, 29b. The die fastening member 38 comprises a pair of left and right members with raised parts 38a that can contact both sides of each of the upper and lower dies 29a, 29b in the lateral direction of the transfer line and can be sandwiched between the contacting surfaces of the upper and lower dies 29a, 29b, and shaped so that each of the left and right members can be bolted to the upper die 29a and the lower die 29b. The bracket 39 shown in Fig. 7 is provided on the surface of each die fastening member 38, to which a connecting member 46 to be detailed later can be bolted. The die changing mechanism 40 comprises a rack 42 alongside the transfer line S as shown in Figs. 7 and 8 that can be correctly aligned with the aforementioned support holder guide rails 31, and has external guide rails 41 on which the die rollers 33 roll and travel, a moving member 44 that is provided with rollers 43 for the moving member which can roll and travel along the above-mentioned external guide rails 41 and the moving member is mounted on the rack 42 by means of the aforementioned rollers 43, a hydraulic cylinder 45 which can drive the above moving member 44 in the lateral direction of the transfer line S, and connecting member 46 that is installed on the moving member 44 and can be connected to the bracket 39 of one of the die fastening members. The rack 42 comprises a base 47, and gate columns 48 erected with a predetermined spacing between each other in the lateral direction of the transfer line on this base 47. The external guide rails 41 are supported by brackets 49 provided at a predetermined height inside the columns 48 and protruding inwards, and which have a pentagonal section with a peak at the top. The moving member 44 comprises a main member 50 and legs 51 constructed at the 4 corners of the main member 50 of the moving member and extending upwards. When the external guide rails 41 are correctly opposite the support holder guide rails 31, one end of the connecting member 46 is bolted to the side of the two legs 51 installed on the transfer line side. The moving member is equipped with rollers 43 which sandwich the external guide rails 41 from above and below, by using 2 rollers at the top of each leg 51. Regarding the hydraulic cylinder 45, the cylinder unit is supported by bearings at the center of the top surface of the base 47 of the rack 42, near the transfer line in a horizontal position such that the cylinder can reciprocate in a direction parallel to the external guide rails 41, and the tip of the piston rod is connected through bearings to the bottom surface of the moving member 50. When hydraulic pressure is applied to the fluid chamber at the rod end of the above-mentioned hydraulic cylinder 45, the moving member 44 travels towards the transfer line. When hydraulic pressure is applied to the fluid chamber at the head end, the moving member 44 is driven in the reverse direction away from the transfer line. With the plate reduction press machine shown in Figs. 5 through 9, a turntable 52 is provided near the press 20 alongside the transfer line S, and two die changing mechanisms 40 are arranged with a predetermined spacing on the top of the turntable 52, and by rotating the turntable 52, the external guide rails 41 of each rack 42 can be correctly aligned with the support holder guide rails 31 of the press 20. When a material 2 to be pressed is pressed in the direction that reduces its thickness using the plate reduction press machine shown in Figs. 5 to 9, the position adjusting screw 37 is rotated appropriately, and the spacing between the upper die 29a and the lower die 29 is determined according to the thickness of the material 2 to be reduced and shaped in the direction of the plate thickness. Next, the motor is operated to rotate the upper and lower crank shafts 24a, 24b, and simultaneously, the material 2 to be pressed is inserted between the upper and lower dies 29a, 29b from the upstream side A of the transfer line. Then, the material 2 to be pressed is pressed, reduced and formed in the direction of plate thickness by the upper and lower dies 29a, 29b when the dies move towards and away from each other and relative to the transfer line S according to the displacement of the eccentric portions of the crank shafts 24a, 24b while traveling from the upstream side A to the downstream side B of the transfer line, along the transfer line S. When the upper and lower dies 29a, 29b are to be replaced, the die fastening members 38 are placed in contact with both sides of the upper and lower dies 29a, 29b, the raised parts 38a are sandwiched between the upper and lower dies 29a, 29b, and then bolts are tightened to connect the upper and lower dies 29a, 29b into one unit, and after that, hydraulic pressure is applied to the fluid chamber at the head end of the hydraulic cylinders 30 that hold the upper dies 29a, 29b, thereby releasing the dies 29a, 29b that were fixed to the die support holders 28a, 28b, and the motor of the press 20 is operated slightly to separate the upper die support holder 28a from the lower die support holder 28b. Then, the turntable 52 is rotated, and is stopped when the external guide rails 41 of the rack 42 of one of the two die changing mechanisms 40 installed on the turntable are correctly aligned with the support holder guide rails 31 of the press 20. Hydraulic pressure is applied to the fluid chamber at the rod end of the hydraulic cylinder 45 of the die changing mechanism 40, thereby driving the moving member 44 to the press machine side, and after connecting the moving member 44 to the bracket 39 of the die fastening member 38 via the connecting member 46, the moving member 44 is moved to the side away from the press machine by applying hydraulic pressure to the fluid chamber at the head end of the hydraulic cylinder 45. Then, the upper and lower dies 29a, 29b connected together by the die fastening members 38 are guided by the support holder guide rails 31 and travel on to the external guide rails 41, using the die rollers provided on the upper die 29a, and as a result, the upper and lower dies 29a, 29b are removed simultaneously from the press machine 20 and transferred to the rack 42 of the die changing mechanism 40. In the meantime, new upper and lower dies 29a, 29b connected together by another pair of die fastening members 38 are mounted on the external guide rails 41 of the rack 42 of another die changing mechanism 40 installed on the turntable 52, and the bracket 39 of the die fastening members 38 is connected to the moving member 44 of the die changing mechanism 40 through the connecting member 46. The turntable 52 is rotated again, and is stopped when the external guide rails 41 of the rack 42 of the other die changing mechanism 40 of the two die changing mechanisms 40 provided on the turntable 52 are correctly aligned with the support guide rails 31 of the press machine. Here, hydraulic pressure is applied to the fluid chamber at the rod end of the hydraulic cylinder 45 of the die changing mechanism 40 to move the moving member 44 towards the press machine, then the upper and lower dies 29a, 29b vertically coupled by the die fastening members 38 connected to the moving member 44 through the connecting member 46, are guided along the external guide rails 41 by the die rollers 33 provided on the upper die 29a, and as a result both upper and lower dies 29a, 29b are transferred simultaneously from the rack 42 of the die changing mechanism 40 to the press machine 20. At this time, the ends of the piston rods of the hydraulic cylinders 30 that fix the upper and lower dies 29a, 29b engage automatically with each of the dovetail grooves 34 provided in the upper and lower dies 29a, 29b. After the upper and lower dies 29a, 29b are transferred to the press machine 20, the connecting member 46 is disconnected from the die fastening members, the motor of the press machine 20 is operated to make the upper die support holder 28a move slightly towards the lower die support holder 28b, and after removing the die fastening members 38 bolted to both sides of the upper and lower dies 29a, 29b, hydraulic pressure is applied to the fluid chambers at the rod ends of the hydraulic cylinders 30 that fix the upper and lower dies 29a, 29b, thereby the dies 29a, 29b are fixed to the die support holders 28a, 28b, respectively. Thus, replacing the dies 29a, 29b is finished. As described above, with the plate reduction press machine shown in Figs. 5 through 9, die fastening members 38 are provided that can connect the upper and lower dies 29a, 29b vertically to form one unit, and the die changing mechanism 40 is also provided that can mount the freely detachable upper and lower dies 29a, 29b on to the press machine 20, so the upper and lower dies 29a, 29b can be quickly replaced, and the plate reduction efficiency of the plate reduction press machine can be maintained at a high level. (Second embodiment) Figs. 10 through 12 show the second embodiment of the apparatus according to the present invention, and the numerals used in Figs. 10 to 12 refer to the same objects as those in Figs. 5 to 9. This press machine comprises tracks 53 installed on one side of the transfer line S and extending in a direction parallel to the line S for transporting a cart 54 that can travel along the tracks 53, a hydraulic cylinder 55 that can move the cart 54, and two die changing mechanisms 40 installed on the cart 54. The tracks 53 consist of a foundation frame 56 installed near the press machine 20 on one side of the transfer line S, and a pair of rails 57 installed substantially horizontally parallel to each other with a predetermined spacing in the lateral direction of the transfer line S on the upper surface of the foundation frame 56, also along the transfer line S. The cart 54 is provided with a plurality of wheels 58 that can roll and move along the rails 57, and a cart body 59 formed to be capable of carrying the die changing mechanisms 40; the external guide rails 41 of each rack 42 of the two die changing mechanisms 40 installed on the cart body 59 can be correctly aligned with the support holder guide rails 31 of the press machine 20 when the cart 54 is moved. The hydraulic cylinder 55 is arranged substantially horizontally inside the foundation frame 56 of the tracks 53; a cylinder unit is supported by bearings from the foundation frame 56 of the tracks 53, and the tip of the piston rod is connected through bearings to the bracket 60 provided on the lower surface of the cart body 59 of the cart 54, and the cart 54 can be moved by applying hydraulic pressure to the fluid chamber at the head end or to the fluid chamber at the rod end. When the upper and lower dies 29a, 29b are to be replaced, the dies 29a, 29b are connected together in the same manner as for the plate reduction press machine shown in Figs. 5 through 9, the dies 29a, 29b fixed on the die support holder 28a, 28b are released, and the upper die support holder 28a is separated slightly from the lower die support holder 28b. Next, hydraulic pressure is applied to the fluid chamber at the head end or rod end of the hydraulic cylinder 55, and the cart 54 is moved and stopped at a location where the external guide rails 41 of the rack 42 of one of the two die changing mechanisms 40 installed on the cart 54 is placed correctly opposite the support holder guide rails 31 of the press machine 20. After that, the upper and lower dies 29a, 29b are removed simultaneously from the press machine 20 using the same operations as those of the press machine shown in Figs. 5 through 9, and the dies are transferred to the rack 42 of the die changing mechanism 40. Meanwhile, new upper and lower dies 29a, 29b connected together using another pair of die fastening members 38 are mounted on the external guide rails 41 of the rack 42 of the other die changing mechanism 40 installed on the cart 54, and the bracket 39 of a die fastening member 38 is connected to the moving member 44 of the die changing mechanism 40, by the connecting member 46. The cart 54 is moved again and stopped at a location where the external guide rails 41 of the rack 42 of the other one of the two die changing mechanisms 40 provided on the cart 54, are aligned correctly in front of the support holder guide rails 31 of the press machine 20. Here, new upper and lower dies 29a, 29b are transferred simultaneously from the rack 42 of the die changing mechanism 40 to the press machine 20 using the same operations as those of the plate reduction press machine shown in Figs. 5 to 9, and the holders 29a, 29b are fixed onto the die support holders 28a, 29b, respectively. The aforementioned operations finish the replacement of the dies 29a, 29b. As described above, the upper and lower dies 29a, 29b can also be replaced quickly with the plate reduction press machine shown in Figs. 10 to 11, in the same way as with the first embodiment of the present invention shown in Figs. 5 to 9, so the plate reduction efficiency of the press machine can be maintained at a high level. (Third embodiment) Fig. 13 shows the third embodiment of the apparatus according to the present invention, and the numerals used in the drawing refer to the same objects as those in Figs. 5 to 9. Die changing mechanisms 61 are arranged on both sides of the transfer line S, and each mechanism comprises a rack 63 provided with external guide rails 62 that can be correctly aligned with the support holder guide rails 31 of the press machine 20 and which allow the die rollers 33 to roll and move thereupon, a hydraulic cylinder 64 that can raise and lower the external guide rails 62 relative to the rack 63, a wire rope 65 of which one end is connected and fixed to one of the die fastening members 38 on one side of the transfer line S and the other end is connected and fixed to the other die fastening member 38 on the other side of the transfer line S, and a winch 66 that pulls the wire rope 65 towards one or the other side of the transfer line S as selected. The rack 63 comprises a base 67 and a pair of diagonal cross arms 68 arranged at a predetermined spacing on the upper surface of the base 67 in the direction parallel to the transfer line S. The diagonal cross arms 68 comprise two links 70, 71 joined with a pin 69 at an intermediate position in the longitudinal direction of the links where they cross each other; one of the links 70 is connected through bearings to a base at the end of the base 67 nearest the press machine 20, and the tip is provided with a bearing that supports one end of the external guide rails 62 on the opposite side to the press machine; the other link 71 comprises a base that is provided on the side opposite to the press machine on the base 67 and is supported in a movable manner by a guide member 72 extending in the lateral direction of the transfer line and a tip that engages with a guide member 73 provided at the end of the external guide rails 62, in a freely movable manner. The hydraulic cylinder 64 comprises a cylinder supported from the center part of the base 67 by bearings, close to the press machine 20, and a piston rod whose tip is connected to the center of the axle 74 that connects the movable base of the other link 71 of the diagonal cross arms 68, in the direction parallel to the transfer line S; when hydraulic pressure is applied to the fluid chamber at the rod end, the piston rod is retracted and the diagonal cross arms 68 are raised, thereby raising the external guide rails 62; and when hydraulic pressure is applied to the fluid chamber at the head end, the piston rod is pushed out and the diagonal cross arm 68 are lifted, so that the external guide rails 62 are lowered. Rope pulleys 75 are arranged on the center line of the press machine, at the far end of the base 67 on each of the racks 63, 63, and rope guide rollers 76 are provided close to the press machine 20 on opposite side of the transfer line S (Side A shown in Fig. 13). A winch 66 is installed near the press machine 20 on the center line of the base of the rack 63 on one side (B side shown in Fig. 13) of the transfer line S. When a wire rope 65 is rewound from the winch 66 on one side (B side in Fig. 13) of the transfer line S, one end thereof passes over the rope pulleys 75, 75 on one side of the transfer line S, and is attached to the bracket 39 of one of the die fastening members 38; and the other end of the wire rope 65, rewound on the other side (Side A in Fig. 13) of the transfer line S, passes over rope guide rollers 76, and rope pulleys 75, 75 at the other end of the transfer line S, and is attached to the bracket 39 of the other die fastening member 38. When the winch 66 is operated in such a direction that the wire rope 65 located on one side (B side in Fig. 13) of the transfer line S is wound in and the wire rope 65 located on the other side (Side A in Fig. 13) is rewound, the upper and lower dies 29a, 29b can be pulled out by one of the die fastening members 38 to one side (B side in Fig. 13) of the transfer line S; when the winch 66 is operated in the opposite direction such that the wire rope 65 located on the one side (B side in Fig. 13) of the transfer line S is rewound and the wire rope 65 located on the other side (Side A in Fig. 13) is wound in, the upper and lower dies 29a, 29b can be pulled out to the other side (Side A in Fig. 13) of the transfer line S. When the upper and lower dies 29a, 29b must be replaced, the dies 29a, 29b are connected together into one unit by the same operations as for the plate reduction press machine shown in Figs. 5 through 9, the dies 29a, 29b fixed to the die support holders 28a, 28b are released, and the upper die support holder 28a is separated slightly from the lower die support holder 28b. Next, hydraulic pressure is applied to the fluid chamber at either the rod or head end of the hydraulic cylinder 64, thereby the external guide rails 62 are raised or lowered, so that the top of the external guide rails 62 is made flush with the top of the support holder guide rails 31 of the press machine. In addition, one end of the wire rope 65 rewound of the winch 65 on one side (B side in Fig. 13) of the transfer line S is attached and fixed to the bracket 39 of one of the die fastening members 38, and the other end of the wire rope 65, rewound to the other side (Side A in Fig. 13) of the transfer line S is fixed to the bracket 39 of the other die fastening member 38. After the above, the winch 65 is operated in such a direction that the wire rope 65 extending on one side (B side in Fig. 13) of the transfer line S is wound in and the wire rope 65 extending on the other side (Side A in Fig. 13) is rewound, the upper and lower dies 29a, 29b are pulled out of the, press machine 20 together, and transferred to the rack 63 of the die changing mechanism 61 on the B side in Fig. 13. At that time, new upper and lower dies 29a, 29b connected together vertically by another pair of die fastening members 38 are mounted on the external guide rails 62 of the rack 63 on the die changing mechanism 61 on the other side (Side A in Fig. 13) of the transfer line, the bracket 39 of the die fastening members 38 on the transfer line side of the dies 29a, 29b is connected to the bracket 39 of the die fastening members 38 on the other side of the transfer line of the old dies 29a, 29b, and the other end of the wire rope 65 is attached and fixed to the bracket 39 of the die fastening members 38 on the side opposite to the transfer line, of the new dies 29a, 29b, thereby the new dies 29a, 29b can be installed in the press machine 20 at the same time that the old dies 29a, 29b are pulled out of the press machine 20. After that, each of the dies 29a, 29b is solidly coupled to each of the die support holders 28a, 28b by the same operations as those of the first embodiment of the present invention shown in Figs. 5 to 9, after disconnecting the die fastening members 38 of the new and old dies 29a, 29b and each end of the wire rope 65. Thus replacing the dies 29a, 29b is completed. Hence, the upper and lower dies 29a, 29b can be replaced as quickly as with the first embodiment of the present invention shown in Figs. 5 through 9, therefore the plate reduction efficiency of the plate reduction press machine can be maintained at a high level. However, the apparatus according to the present invention is not limited only to the embodiments described above, but various modifications, for example, a single die changing mechanism can also be provided beside the press machine, are also included in the scope of the invention, as a matter of course. As described above, the apparatus according to the present invention can offer the following miscellaneous excellent advantages. (1) The apparatus according to the present invention, comprises die fastening members that can clamp the upper and lower dies vertically together to form a single unit, and die exchanging mechanisms that can move the die fastening members in the direction lateral to the transfer line, therefore the operation of replacing upper and lower dies can be carried out quickly, and the plate thickness reduction efficiency of the press machine can be maintained at a high level. (2) With the preferred embodiment of the die changing apparatus for a plate reduction press machine, specified in Claim 2 of the present invention, the actuator of the die changing mechanism is operated to quickly transfer the upper and lower dies connected together into a single unit by the die fastening members using the moving member equipped with rollers, from the upper and lower die support holders to the external guide rails on the rack. (3) In any of the preferred embodiments of the die changing apparatuses for a plate reduction press machine described in Claims 3, 4 and 6 of the present invention, two or more die changing mechanisms are provided, with which old dies can be removed by one die changing mechanism and new dies can be mounted by another die changing mechanism, so that dies can be replaced more quickly. (4) With the preferred embodiment of the die changing apparatus for a plate reduction press machine, specified in Claim 5 of the present invention, the winch of the die changing mechanism is operated to quickly move the upper and lower dies connected together by the die fastening members, using the pulling rope, from the upper and lower die support holders to the external guide rails of the rack. Fig. 14 is a view showing the configuration of a press machine using the split dies of the first embodiment according to the present invention. The press machine consists of split dies 202 arranged vertically above and below a material 201 to be pressed, die clamps 203 holding the split dies 202 together to form a single body, and a pressing apparatus 204 that applies a pressing load to the split dies 202 via the die clamps 203. Although Fig. 19 schematically shows a crank mechanism as the pressing apparatus 204, another mechanism such as a hydraulic cylinder may also be used. Fig. 15 is a view in the direction of the arrows X-X in Fig. 14, showing a plan view of the first embodiment of split dies used in the inventive apparatus. In Fig 15, the dies consist of a plurality of split segments 202 arranged closely to each other in the lateral direction of a material 201 to be pressed. In Fig, 15, 5 split segments 202 are shown, but the plurality of split segments can be adjusted appropriately according to the width of the material 201 to be pressed. The planar shape of a split segment 202 in plan view is rectangular, and the surface facing the material 201 to be pressed is configured as a plane 202a parallel to the surface of the material 201 and a sloping surface 202b inclined to the surface of the material 201. Fig. 16 shows an example of a passage for cooling water, provided in a split die 202. (A) and (B) show a side view and a view in the direction of the arrows Y-Y, respectively. The cooling water passage 205 is constructed inside the split die 202, to pass cooling water, and a hose not illustrated is connected to supply the cooling water. Thereby, even when a high-temperature slab etc. is to be pressed, the split die 202 can be maintained at a low temperature, so that the life of the split die 202 can be made longer. Fig. 17 shows grooves 206 or raised parts 207 formed on the parallel and sloping surfaces 202a, 202b of the split die 202. (A) is concerned with a case in which a plurality of circular grooves 206 partially superimposed on each other, are formed on the parallel and sloping surfaces 202a, 202b. (B) is a case in which a plurality of straight grooves 206 are formed on the parallel and sloping surfaces 202a, 202b in the direction of movement of the material 201 to be pressed. (C) represents a case in which a plurality of straight grooves 206 aligned in the direction perpendicular to the direction in which the material 201 to be pressed is moved are formed on the parallel and sloping surfaces 202a, 202b. In (D), a plurality of straight grooves 206 in the direction of movement of the material 201 to be pressed are formed on the parallel surface 202a, and straight grooves 206 in the direction perpendicular to the direction of movement of the material 201 to be pressed are formed on the sloping surface 202b. (E) is a case in which a diagonal check pattern of grooves 206 is formed on the parallel and sloping surfaces 202a, 202b. (F) shows many square raised portions 207 formed on the parallel and sloping surfaces 202a, 202b. In this manner, by incorporating grooves 206 or raised portions 207, slippage during pressing, between the dies and the material being pressed 201, is reduced. In addition, because the volume of the material being pressed 201 substantially does not change even during pressing, a volume of material proportional to the reduction in thickness, must be displaced (this is called the deformation flow of the material). These grooves 206 or raised portions 207 can control the direction of this deformation flow. A further embodiment of the split dies used in the inventive apparatus is described below. Fig. 18 is a view in the direction of the arrows X-X in Fig. 14 and shows said further embodiment of the split dies 202. With the split dies 202 of this embodiment, the surfaces of a die 202 in contact with adjacent dies are inclined to the direction of movement (longitudinal direction) of the material 201 to be pressed, and this is a difference from the split dies 202 of the first embodiment shown in Fig. 15. The cooling water passages 205 shown in Fig. 16 are provided also in the split dies 202 of said further embodiment on which the grooves 206 or raised portions 207 shown in Fig. 22 are constructed on either or both the parallel and sloping surfaces 202a, 202b. As the surfaces of a die in contact with adjacent dies 202 are skewed in this way, stripes that may be produced longitudinally in the material 201 to be pressed when it is being pressed, can be reduced. Obviously from the foregoing descriptions, the invention apparatus comprising said split dies offers the following advantages. 1) By dividing dies in the lateral direction of the material 201 to be pressed, cracks and deformation of the dies can be suppressed. When dies wear, it is possible to replace only the split dies in the center which have the greatest wear. In addition, the plurality of split dies to be used can be varied depending on the width of the material 201 to be pressed, so the plurality of dies to be prepared can be reduced compared to when dies have to be prepared for all widths of materials to be pressed 201. Moreover, split dies can be manufactured more easily at a lower cost. 2) By making the contact surfaces of a split die in contact with the adjacent split dies inclined to the longitudinal direction of the transfer line, longitudinal stripes produced when a material 201 to be pressed is pressed, can be reduced. 3) By cooling split dies with cooling water through internal passages, the life of the dies can be prolonged. 4) By constructing grooves 206 or raised portions 207 on the parallel and sloping surfaces of dies, slippage between the material being pressed 201 and the dies can be reduced. In addition, the direction of the deformation flow of the material being pressed 201 can be controlled to a preferred direction. The present invention has been described referring to several preferred embodiments, but it should be understood that the scope of the rights claimed in the present invention is not limited to these embodiments. Conversely, the scope of the claims of the present invention should include all modifications, corrections or the like to be included in the scope of the attached claims.

Claims: A die changing apparatus for a plate reduction press machine (20) used in a hot rolling transfer line (S), comprising: an upper die support holder (28a), placed above said transfer line (S), and a lower die support holder (28b), placed below said transfer line (S) such that said die support holders (28a, 28b) are placed vertically on opposite sides of said transfer line (S), support holder guide rails (3) fixed to the upper die support holder (28a) and extending substantially horizontally in the lateral direction of the transfer line (S), an upper die (29a) equipped with die rollers (33) capable of rolling along the guide rails (31) and is mounted on the upper die support holder (28a) by means of the die rollers (33), a first fixing device (30) capable of fixing the upper die (29a) to the upper die support holder (28a), a lower die (29b) mounted on the lower die support holder (28b), a second fixing device (30) capable of fixing the lower die (29b) to the lower die support holder (28b), die fastening members (38) arranged opposite each other on each side of the upper and lower dies (29a, 29b) and capable of being connected to each of the upper and lower dies (29a, 29b), and a die changing mechanism (40) that moves said dies (29a, 29b) and the fastening members (38) substantially horizontally in the lateral direction of the transfer line (S) by being connected to one of said die fastening members (38). The die changing apparatus specified in claim 1, in which the die changing mechanism (40) comprising: a rack comprised of external guide rails (41) that can be placed correctly opposite the support holder guide rails (31) alongside the transfer line (S) and allow the die rollers (33) to roll and move thereon, a moving member (44) comprised of moving-member rollers (43) capable of rolling and moving on the external guide rails (41) and is mounted on the rack (42) by means of the moving-member rollers (43), an actuator (45) capable of moving the moving-member in the lateral direction of the transfer line (S), and a connecting member (46) that is fixed to the moving member (44) and capable of being connected to one of the die fastening members (38). The die changing apparatus specified in claim 2, comprising a plurality of the die changing mechanisms (40) mounted on a turntable (52) located alongside the transfer line (S) in such a manner that the external guide rails (41) concerned with each die changing mechanism (40) can be placed correctly opposite the support holder guide rails (31) when the turntable (52) rotates. The die changing apparatus specified in claim 2, comprising a plurality of the die changing mechanisms (40) which are mounted on a cart (54) arranged alongside the transfer line (S) that can be moved along the direction of the transfer line (S) in such a manner that the external guide rails (41) concerned with each die changing mechanism (40) can be placed correctly opposite the support holder guide rails (31) when the cart is moved. The die changing apparatus specified in claim 1, comprising a rack (63) comprised of external guide rails (62) that can be placed correctly opposite the support holder guide rails (31) alongside the transfer line (S) and allow the die rollers (33) to roll and move thereon, a pulling rope (65) one end of which can engage with one of the die fastening members (38) on one side of the transfer line (S) and the other end can engage with the other die fastening member (38) on the other side of the transfer line (S), and a winch (66) that pulls the pulling rope (65) towards either side of the transfer line (S) as selected. The die changing apparatus specified in claim 5, comprising two racks (63) arranged on opposite sides of the transfer line (S) in such a manner that the external guide rails (62) of each rack can be placed correctly opposite the support holder guide rails (31). Apparatus according to claim 1, comprising an upper die (202) and a lower die (202) which press the material (201) there between, with parallel surfaces (202a) and sloping surfaces (202b) facing the material (201) to be pressed, where the press dies (202) comprise a plurality of segments divided in the lateral direction of the material (201) to be pressed. Apparatus according to claim 7, in which the surface of one of the segments of the dies (202), in contact with the surface of an adjacent segment is inclined to the direction of movement of the material (201) to be pressed. Apparatus according to claim 7, provided with passages (205) for cooling water inside the segments of the dies (202). Apparatus according to claim 7, in which a plurality of grooves (206) are formed on at least one of the parallel surfaces (202a) and sloping surfaces (202b) of the segments of the dies (202). Apparatus according to Claim 7, in which a plurality of raised portions (207) are formed on at least one of the parallel surfaces (202a) and sloping surfaces (202b) of the segments of the dies (202). A method for operating an apparatus according to claim 1, comprising the steps of: placing said fastening member (38) in contact with both sides of said upper and lower dies (29a, 29b), releasing said dies (29a, 29b) from said first and second fixing device (30), aligning external guide rails (31) of said die changing mechanism (40) with support holder guide rails (31) of said press machine (20), moving a moving member (44), which rolls on said external guide rails (31), to said press machine (20) side, connecting said moving member (44) to said fastening member (38) via a connecting member (46), and moving said moving member (44) to a side away from said press machine (20), wherein said dies (29a, 29b) are guided by said support holder guide rails (31) and travel on the external guide rails (41), using said die rollers (33) provided on the upper die (29a), thereby removing said dies (29a, 29b) from said press machine (20).

Inventors: DODO YASUSHI, FUJII YASUHIRO, IDE KENICHI, IKEMUNE SHOZO, MASUDA SADAKAZU, NARUSHIMA SHIGEKI, TAZOE NOBUHIRO, YAMASHINA SHUICHI, DODO, YASUSHI, FUJII, YASUHIRO, IDE, KENICHI, IKEMUNE, SHOZO, MASUDA, SADAKAZU, NARUSHIMA, SHIGEKI, TAZOE, NOBUHIRO, YAMASHINA, SHUICHI
Applicants: ISHIKAWAJIMA HARIMA HEAVY IND, JFE STEEL CORP, ISHIKAWAJIMA-HARIMA HEAVY INDUSTRIES CO., LTD., JFE STEEL CORPORATION
Application year: 1998
Main classification: B21B15
IPC codes: B21J1, B21B15