Wiping nozzle of hot-dip metal plating equipment and wiping position control device for hot-dip metal plating equipment

Abstract

The present invention reduces the amount of gas consumed, edge-overcoating and splashing and adjusts plating thickness with high precision by providing a wiping nozzle with: thin plates, which are each inserted into a lip from the entrances to the lip for a specified distance to the inside of the two ends of the lip in the sheet width direction in order to seal the gas jet where the thin plates are inserted, and which are movable in the sheet width direction of the lip; and ropes extending in the sheet width direction of the lip so as to track the movements of the thin plates and seal the gas jet in a specified range.

Claims

1. A wiping nozzle of hot-dip metal plating equipment, including a lip which is a slit extending in a plate-width direction of a steel plate and blows a gas jet, and being configured to blow the gas jet onto the steel plate to adjust a plating thickness of the steel plate, characterized in that the wiping nozzle comprises: plates inserted from an inlet of the lip into the lip at positions located inward respectively from end portions of the lip in the plate-width direction by a predetermined distance, to seal in the gas jet at inserted portions, the plates being capable of moving in the plate-width direction; and ropes extending in the plate-width direction in such a manner as to follow movements of the plates to seal in the gas jet in a range of the predetermined distance, thereby making variable a length of a blowing port for the gas jet of the lip in the plate-width direction; the wiping nozzle comprising: two sliding tables capable of moving in the plate-width direction; first pulleys disposed on the respective sliding tables; second pulleys disposed on the respective sliding tables at positions inward of the corresponding first pulleys in the plate-width direction, and in contact with an inlet of the lip; and protrusions disposed from the corresponding second pulleys inward in the plate-width direction, wherein each rope is wound on the corresponding first pulley and the corresponding second pulley, is fixed at opposite end portions thereof, and is slidably fitted to the inlet of the lip in a range from each of the opposite end portions to a contact point with the corresponding second pulley, and the plates are supported on the respective protrusions.

2. The wiping nozzle of hot-dip metal plating equipment according to claim 1, wherein the plates are capable of moving in a direction opposite to a blowing direction of the gas jet.

3. A wiping position control device for hot-dip metal plating equipment, comprising: a plurality of wiping nozzles of hot-dip metal plating equipment according to claim 1, the wiping nozzles being disposed to face each other on a front surface side and a back surface side of the steel plate; a plate end position measuring unit which measures positions of opposite end portions of the steel plate in the plate-width direction; a sliding table drive position calculating unit which calculates positions of the sliding tables such that the positions correspond to the positions of the opposite end portions of the steel plate in the plate-width direction, based on a measurement result by the plate end position measuring unit; and a sliding table driving unit which drives the sliding tables, based on a calculation result by the sliding table drive position calculating unit.

4. A wiping position control device for hot-dip metal plating equipment, comprising: a plurality of wiping nozzles of hot-dip metal plating equipment according to claim 2, the wiping nozzles being disposed to face each other on a front surface side and a back surface side of the steel plate; a plate end position measuring unit which measures positions of opposite end portions of the steel plate in the plate-width direction; a sliding table drive position calculating unit which calculates positions of the sliding tables such that the positions correspond to the positions of the opposite end portions of the steel plate in the plate-width direction, based on a measurement result by the plate end position measuring unit; and a sliding table driving unit which drives the sliding tables, based on a calculation result by the sliding table drive position calculating unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a top view for describing a wiping nozzle of hot-dip metal plating equipment according to Embodiment 1 of the present invention.

(2) FIG. 2 is a view in a direction of arrows A-A in FIG. 1.

(3) FIG. 3 is a top view for describing a wiping nozzle of hot-dip metal plating equipment according to Embodiment 2 of the present invention.

(4) FIG. 4 is a graph illustrating a distribution, in a plate-width direction of the wiping nozzle, of a ratio of a gas jet impact pressure to a maximum gas jet impact pressure of the wiping nozzle of hot-dip metal plating equipment according to Embodiment 2 of the present invention.

(5) FIG. 5 is schematic views for describing a wiping nozzle of hot-dip metal plating equipment according to Embodiment 3 of the present invention, Part (a) illustrates the event of sealing a nozzle lip, and Part (b) illustrates the event of cleaning.

(6) FIG. 6 is schematic views for describing a wiping position control device for hot-dip metal plating equipment according to Embodiment 4 of the present invention, Part (a) illustrates a side view, Part (b) illustrates a top view, and Part (c) illustrates a flowchart.

MODES FOR CARRYING OUT THE INVENTION

(7) Hereinafter, a wiping nozzle of hot-dip metal plating equipment and a wiping position control device for hot-dip metal plating equipment according to embodiments of the present invention will be described with reference to the drawings.

Embodiment 1

(8) A wiping nozzle of hot-dip metal plating equipment according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a top view for explaining the wiping nozzle of hot-dip metal plating equipment according to Embodiment 1 of the present invention, and FIG. 2 is a view in a direction of arrows A-A in FIG. 1.

(9) The wiping nozzle (wiping nozzle 11) of hot-dip metal plating equipment according to Embodiment 1 of the present invention has an internal space formed into a passage chamber for a compressed gas, and has a shape extended in a plate-width direction of a steel plate, like the conventional techniques. As illustrated in FIGS. 1 and 2, the wiping nozzle 11 includes a guide 12, a sliding table drive screw 13, a sliding table 14, a first pulley 16a, a second pulley 16b, a rope 17, a fixing portion 18, a thin plate supporting portion 19, a thin plate 20, and a lip 21, and is blowing a gas jet onto a steel plate 10 as indicated by outlined arrows in FIG. 1. Here, the guide 12, the sliding table drive screw 13, the sliding table 14, the first pulley 16a, the second pulley 16b, the rope 17, the fixing portion 18, the thin plate supporting portion 19, and the thin plate 20 are disposed inside the wiping nozzle 11.

(10) Note that the mechanism illustrated in FIG. 1 is part of the wiping nozzle 11, and a mechanism obtained by laterally inverting the mechanism illustrated in FIG. 1 is provided on the opposite side in the lip plate-width direction (the same applied to FIGS. 3 and 5 described later). Hereinafter, only a range illustrated in FIG. 1 will be described.

(11) The sliding table 14 is slidably fitted to the guide 12 extended in the lip plate-width direction. This allows the sliding table 14 to move in the lip plate-width direction as indicated by an outlined double-headed arrow in FIG. 1. In addition, the sliding table 14 is positioned by the sliding table drive screw 13.

(12) The first pulley 16a and the second pulley 16b are each disposed on the sliding table 14. In addition, the second pulley 16b is disposed at a position inward of the first pulley 16a in the lip plate-width direction, and in contact with an inlet of the lip 21 (a portion with a length L).

(13) The rope 17 extends in the lip plate-width direction and is wound on the first pulley 16a and the second pulley 16b. In addition, an end portion of the rope 17 is fixed to the fixing portion 18 disposed at an end portion in the lip plate-width direction, so that a tensile force is applied to the rope 17. Note that the material of the rope 17 may be a fiber, a metal, and the like, but is not particularly limited to any material here.

(14) Moreover, the rope 17 is slidably fitted to the inlet of the lip 21 in a range W (see FIG. 1) from the end portion to a contact point with the second pulley 16b. This allows the rope 17 to seal in the gas jet blown out in a region a (see FIG. 1) from the end portion to the second pulley 16b in the lip 21. In other words, the rope 17 plays a role as a seal member.

(15) The thin plate supporting portion 19 is disposed in such a manner as to have a protrusion from the second pulley 16b inward in the lip plate-width direction.

(16) The thin plate 20 is supported on the protrusion of the thin plate supporting portion 19 and is inserted in the lip 21. This allows the thin plate 20 to seal in the gas jet blown out in a region b (see FIG. 1) further inward of the portion sealed by the rope 17 (inward of the second pulley 16b in the lip plate-width direction).

(17) The lip 21 is configured such that since in the regions a and b in FIG. 1, the gas jet is sealed in by the rope 17 and the thin plate 20, a region c serves as a gas jet blowing port. Note that the region c is set to be longer than the plate width of the steel plate 10.

(18) With the above-described configuration, when supplied with a compressed gas as indicated by the downward outlined arrows in FIG. 1, the wiping nozzle 11 blows out the gas jet from the lip 21. At this time, adjustment using the pulleys 16a and 16b causes the rope 17 and the thin plate 20 to move in the lip plate-width direction, thereby changing the ranges of the regions a and b where the gas jet is sealed in. As a result, the width of the region c in the gas jet blowing port can be changed.

(19) In addition, although in FIG. 2, the thickness of the thin plate 20 is illustrated as being equal to a slit gap g of the lip 21, this embodiment is capable of securing the effect of blocking the gas jet even when the thickness of the thin plate 20 is set to be equal to or more than half of the gap g, but less than the gap g. Moreover, since there is almost no sliding resistance in moving the thin plate 20, the thin plate 20 can be moved smoothly even when the rope 17 is deflected or waved. Thus, the precision and response in positioning the thin plate 20 are improved.

(20) Moreover, in FIGS. 1 and 2, the length of the thin plate 20 in a gas jet blow direction is illustrated as being equal to the length L of the slit of the lip 21 in the gas jet blow direction (hereinafter referred to as a lip length L). The length of the thin plate 20 in the gas jet blow direction is preferably equal to the lip length L as described here, but may be shorter than the lip length L.

(21) Then, the width of the thin plate 20 in the lip plate-width direction (the region b in FIG. 1) is preferably equal to or more than the radius of the pulley 16b+20 mm from the center of the pulley 16b.

(22) The wiping nozzle 11 has been described above, and what is important for the wiping nozzle 11 is that part of the gas jet from the lip 21 is sealed in by the rope 17 and the thin plate 20 placed inward thereof, and also, that the range to seal is made changeable.

(23) As in the wiping nozzle described in Patent Document 3, with only the seal using a wire, the gas flow is disturbed at the end portions of the wire, and thus the wiping ability is lowered. By contrast, in the wiping nozzle 11, since the thin plate 20 is provided inward of the rope 17, the gas flow is not disturbed, and the wiping ability is improved.

(24) In addition, in general, a wiping nozzle needs to be cleaned particularly at the tip of the lip. In this regard, when the length of the thin plate 20 in the gas jet blow direction is made equal (or substantially equal) to the lip length L, the thin plate 20 naturally serves as a cleaner as well, so that the tip of the lip 21 can be cleaned by the moving thin plate 20.

(25) In other words, the wiping nozzle of hot-dip metal plating equipment according to Embodiment 1 of the present invention is a wiping nozzle of hot-dip metal plating equipment, including a lip which is a slit extending in a plate-width direction of a steel plate and blows a gas jet, and being configured to blow the gas jet onto the steel plate to adjust a plating thickness of the steel plate, the wiping nozzle including: a thin plate inserted from an inlet of the lip into the lip at a position located inward from each of end portions of the lip in the plate-width direction by a predetermined distance, to seal in the gas jet at an inserted portion, the thin plate being capable of moving in the plate-width direction; and a rope extending in the plate-width direction in such a manner as to follow movement of the thin plate to seal in the gas jet in a range of the predetermined distance.

(26) Therefore, the wiping nozzle of hot-dip metal plating equipment according to Embodiment 1 of the present invention is capable of reducing the amount of gas consumed, edge-overcoating, and splashing only with the functions inside the wiping nozzle. Accordingly, any baffle plate is unnecessary, and a damping device and the nozzle can be arranged adjacent to each other to enhance the dampening effect. In addition, the reduction in splashing allows the distance between the wiping nozzle and the steel plate to be shortened, so that the wiping ability is improved and the plating thickness can be adjusted with high precision. Then, it is possible to achieve a uniform thin plating even at a high line speed, making it possible to enhance the production speed.

Embodiment 2

(27) A wiping nozzle of hot-dip metal plating equipment according to Embodiment 2 of the present invention is configured by changing a configuration of part of the wiping nozzle of hot-dip metal plating equipment according to Embodiment 1, thereby stabilizing the gas flow at an inner end portion of the thin plate in the lip plate-width direction.

(28) Hereinafter, the wiping nozzle of hot-dip metal plating equipment according to Embodiment 2 of the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a top view for describing the wiping nozzle of hot-dip metal plating equipment according to Embodiment 2 of the present invention. FIG. 4 is a graph illustrating a distribution, in the plate-width direction of the wiping nozzle, of a ratio of a gas jet impact pressure to a maximum gas jet impact pressure of the wiping nozzle of hot-dip metal plating equipment according to Embodiment 2 of the present invention.

(29) The wiping nozzle (wiping nozzle 31) of hot-dip metal plating equipment according to Embodiment 2 of the present invention has an internal space formed into a passage chamber for a compressed gas, and has a shape extended in a plate-width direction of a steel plate, like the wiping nozzle 11 of Embodiment 1. Then, as illustrated in FIG. 3, the wiping nozzle 31 includes a guide 12, a sliding table drive screw 13, a sliding table 14, a first pulley 16a, a second pulley 16b, a rope 17, a fixing portion 18, a thin plate supporting portion 19, a thin plate 40, and a lip 21.

(30) The guide 12, the sliding table drive screw 13, the sliding table 14, the first pulley 16a, the second pulley 16b, the rope 17, the fixing portion 18, the thin plate supporting portion 19, and the lip 21 are the same as those of Embodiment 1, and thus will not be described.

(31) The thin plate 40 is supported on a protrusion of the thin plate supporting portion 19 and is inserted in the lip 21, like the thin plate 20 of the Embodiment 1. This allows the thin plate 40 to seal in the gas jet blown out in a region b (see FIG. 1) further inward of the portion sealed by the rope 17 (inward of the second pulley 16b in the lip plate-width direction).

(32) Moreover, in this embodiment, the inner end portion of the thin plate 40 in the lip plate-width direction is inclined, or the inner end portion in the lip plate-width direction is formed in an arc shape, to narrow an outlet side more than an inlet side in a gas jet blowing port (corresponding to the region c in FIG. 1) of the lip 21. Note that FIG. 2 illustrates the case where the inner end portion in the lip plate-width direction is inclined.

(33) In the graph of FIG. 4, the vertical axis indicates (gas jet impact pressure)/(maximum gas jet impact pressure), and the horizontal axis indicates the coordinate (position) in the lip plate-width direction. In addition, it is assumed that the thin plate 40 is provided on the negative side of the point of 0 mm on the horizontal axis, and the inner end portion of the thin plate 40 in the lip plate-width direction is located at the point of 0 mm. Note that when (gas jet impact pressure)/(maximum gas jet impact pressure) is zero, it means that the gas jet is not blown at all from the wiping nozzle, and when (gas jet impact pressure)/(maximum gas jet impact pressure) is one, it means that the gas jet is being blown completely from the wiping nozzle (there is no influence of the sealing member on the gas flow).

(34) As illustrated in the graph of FIG. 4, in the region provided with the thin plate 40, the gas jet is almost sealed in (from 20 mm to near 0 mm). On the other hand, in the region not provided with the thin plate 40, the gas jet is being blown completely (from near 0 mm to 20 mm). Then, near 0 mm, the blowing amount of the gas jet changes largely and stably.

Embodiment 3

(35) As for the wiping nozzle of hot-dip metal plating equipment according to Embodiment 1 of the present invention, the configuration in which the thin plate serves as a cleaner as well, making it possible to clean the tip of the lip, has been described. A wiping nozzle of hot-dip metal plating equipment according to Embodiment 3 of the present invention is configured by changing configurations of part of the wiping nozzles of hot-dip metal plating equipment according to Embodiments 1 and 2 so as to cause the thin plate to move into the wiping nozzle, thereby improving convenience during cleaning by a worker and during cleaning using a separate cleaner.

(36) Hereinafter, the wiping nozzle of hot-dip metal plating equipment according to Embodiment 3 of the present invention will be described with reference to Part (a) of FIG. 5. FIG. 5 is schematic views for describing the wiping nozzle of hot-dip metal plating equipment according to Embodiment 3 of the present invention, and Part (a) of FIG. 5 illustrates the event of sealing a nozzle lip.

(37) The wiping nozzle (wiping nozzle 51) of hot-dip metal plating equipment according to Embodiment 3 of the present invention has an internal space formed into a passage chamber for a compressed gas, and has a shape extended in a plate-width direction of a steel plate, like the wiping nozzles 11 and 31 of Embodiments 1 and 2. Then, as illustrated in Parts (a) and (b) of FIG. 5, the wiping nozzle 51 includes a guide (not illustrated), a sliding table drive screw (not illustrated), a spring 52, a sliding table 54, a first pulley 56a, a second pulley 56b, a rope 17, a fixing portion (not illustrated), a lever 59, a thin plate 60, and a lip 21.

(38) The guide, the sliding table drive screw, the rope 17, the fixing portion, and the lip 21 are the same as those of Embodiments 1 and 2, and thus will not be described.

(39) The sliding table 54, although not illustrated, is slidably fitted to the guide extended in a lip plate-width direction, like the sliding tables 14 in Embodiments 1 and 2. This allows the sliding table 54 to move in the lip plate-width direction. In addition, the sliding table 54 is positioned by the sliding table drive screw 13. Moreover, in this embodiment, the spring 52 is disposed on the sliding table 54.

(40) The lever 59 is connected to the spring 52, and disposed on a rotational shaft 53a of the first pulley 56a and a rotational shaft 53b of the second pulley 56b. The lever 59 is disposed in such a manner as to have a protrusion from the second pulley 56b inward in the lip plate-width direction.

(41) In addition, the rotational shaft 53a of the first pulley 56a is fixed to the sliding table 54, and the rotational shaft 53b of the second pulley 56b is not fixed.

(42) The thin plate 60 is supported on the protrusion of the lever 59, and is inserted in the lip 21. This allows the thin plate 60 to seal in the gas jet blown out in a region (see the region b in FIG. 1) further inward of the portion sealed by the rope 17 (inward of the second pulley 56b in the lip plate-width direction). In other words, in this embodiment, the lever 59 plays also a role of the thin plate supporting portion 19 in Embodiments 1 and 2.

(43) In addition, in this embodiment, as illustrated in Part (a) of FIG. 5, the length of the thin plate 60 in the gas jet blow direction is equal to the lip length L.

(44) In the wiping nozzle 51 of the above-described configuration, in the event of sealing the nozzle lip, as indicated by an outlined arrow on the rope 17 in Part (a) of FIG. 5, a tensile force is applied to the rope 17 by the fixing portion (see the fixing portion 18 in FIGS. 1 and 3). In addition, as indicated by an outlined arrow on the spring 52, a spring force is applied to the lever 59 by a spring 52. Then, the tensile force and the spring force are balanced out so that the thin plate 60 is stopped at a predetermined position.

(45) How the lip 21 of the wiping nozzle 51 is cleaned will be described below with reference to Part (b) of FIG. 5. Note that Part (b) of FIG. 5 illustrates one for the event of cleaning among the schematic views for describing the wiping nozzle of the hot-dip metal plating equipment according to Embodiment 3 of the present invention.

(46) First, the tensile force applied to the rope 17 by the fixing portion is removed. Once the tensile force is removed, the lever 59 is rotated about the rotational shaft 53a of the first pulley 56a by the spring force of the spring 52. The rotation of the lever 59 about the rotational shaft 53a causes the second pulley 56b and the protrusion of the lever 59 to move away from the lip 21. Thus, the thin plate 60 also moves away from the tip of the lip 21 (C in Part (b) of FIG. 5).

(47) In other words, the wiping nozzle of hot-dip metal plating equipment according to Embodiment 3 of the present invention is such that in a case where the thin plate and the lip have an equal length in the blowing direction of the gas jet, when the thin plate is made movable in a direction opposite to the blowing direction, it is possible to maximize the advantageous effect by sealing the entire lip length L, and also to prevent the thin plate from obstructing the cleaning of the tip of the lip. Thus the convenience in cleaning is improved, leading to avoidance of clogging of the lip and improvement in operation rate.

(48) Note that in this embodiment, the cleaning of the tip of the lip may be conducted by a worker, or may be automatically conducted by providing a cleaner.

Embodiment 4

(49) A wiping position control device for hot-dip metal plating equipment according to Embodiment 4 of the present invention is a device that performs such control that the positions of the thin plates of the wiping nozzle of hot-dip metal plating equipment according to any of Embodiments 1 to 3 follow the positions of the opposite end portions of a steel plate in the plate-width direction, during plate-width change or meandering of the steel plate.

(50) First, the wiping position control device for hot-dip metal plating equipment according to Embodiment 4 of the present invention will be described with reference to FIG. 6. FIG. 6 is schematic views for describing the wiping position control device for hot-dip metal plating equipment according to Embodiment 4 of the present invention. Part (a) of FIG. 6 illustrates a side view, Part (b) of FIG. 6 illustrates a top view, and Part (c) of FIG. 6 illustrates a flowchart.

(51) As illustrated in Parts (a) and (b) of FIG. 6, the wiping position control device for hot-dip metal plating equipment according to Embodiment 4 of the present invention includes a first wiping nozzle 71, a second wiping nozzle 81, plate end position measuring units 91a, 91b, a sliding table drive position calculating unit 92, and sliding table driving units 93a, 93b.

(52) The wiping nozzles 71, 81 have the same configuration as those of the wiping nozzles 11, 31, 51 of Embodiments 1 to 3, and disposed to face each other on a front surface side and a back surface side of a steel plate 10. Note that Part (b) of FIG. 6 illustrates only sliding tables 74a, 74b inside the wiping nozzle 71 and sliding tables 84a, 84b inside the wiping nozzle 81.

(53) The plate end position measuring units 91a, 91b are sensors for measuring the positions of the opposite end portions of the steel plate 10 in a plate-width direction.

(54) The sliding table drive position calculating unit 92 calculates the positions of the sliding tables 74a, 74b, 84a, 84b such that the positions correspond to the positions of the opposite end portions of the steel plate 10 in the plate-width direction, based on a measurement result by the plate end position measuring units 91a, 91b.

(55) The sliding table driving units 93a, 93b drive the sliding tables 74a, 74b, 84a, 84b, based on a calculation result by the sliding table drive position calculating unit 92.

(56) With the above-described configuration, as illustrated in the flowchart of Part (c) of FIG. 6, the wiping position control device for hot-dip metal plating equipment according to Embodiment 4 of the present invention: first measures the positions of the opposite end portions of the steel plate 10 in the plate-width direction with the plate end position measuring units 91a, 91b as step S1; next calculates the positions of the sliding tables 74a, 74b, 84a, 84b such that the positions correspond to the positions of the opposite end portions of the steel plate 10 in the plate-width direction with the sliding table drive position calculating unit 92 as step S2; and drives the sliding tables 74a, 74b, 84a, 84b with the sliding table driving units 93a, 93b as step S3. In this way, the device performs such control that the positions of the thin plates (see the thin plate 20 in FIG. 1) follows the positions of the opposite end portions of the steel plate 10 in the plate-width direction, during plate-width change or meandering of the steel plate 10.

(57) The wiping position control device for hot-dip metal plating equipment according to Embodiment 4 of the present invention have been described above. In other words, the wiping position control device for hot-dip metal plating equipment according to Embodiment 4 of the present invention is a wiping position control device for hot-dip metal plating equipment, including: wiping nozzles of hot-dip metal plating equipment, each of which is any one of the wiping nozzles according to Embodiments 1 to 3 and which are disposed to face each other on a front surface side and a back surface side of the steel plate; a plate end position measuring unit which measures positions of opposite end portions of the steel plate in a plate-width direction; a sliding table drive position calculating unit which calculates positions of the sliding tables such that the positions correspond to the positions of the opposite end portions of the steel plate in the plate-width direction, based on a measurement result by the plate end position measuring unit; and a sliding table driving unit which drives the sliding tables, based on a calculation result of the sliding table drive position calculating unit.

(58) Therefore, the wiping position control device for hot-dip metal plating equipment according to Embodiment 4 of the present invention is capable of causing a gas jet blowing region of the wiping nozzle to follow an appropriate position in conformity with the steel plate, during plate-width change or meandering of the steel plate, and thus enables the wiping of the opposite end portions in the plate-width direction accurately.

INDUSTRIAL APPLICABILITY

(59) The present invention is favorably applicable to a wiping nozzle of hot-dip metal plating equipment and a wiping position control device for hot-dip metal plating equipment.

REFERENCE SIGNS LIST

(60) 11, 31, 51, 71, 81 WIPING NOZZLE 12 GUIDE 13 SLIDING TABLE DRIVE SCREW 14, 54, 74a, 74b, 84a, 84b SLIDING TABLE 16a FIRST PULLEY 16b SECOND PULLEY 17 ROPE (SEAL MEMBER) 18 FIXING PORTION 19 THIN PLATE SUPPORTING PORTION 20, 40, 60 THIN PLATE 52 SPRING 53a FIRST PULLEY ROTATIONAL SHAFT 53b SECOND PULLEY ROTATIONAL SHAFT 56a FIRST PULLEY 56b SECOND PULLEY 59 LEVER 91a, 91b PLATE END POSITION MEASURING UNIT 92 SLIDING TABLE DRIVE POSITION CALCULATING UNIT 93a, 93b SLIDING TABLE DRIVING UNIT