Crucible tray and control method of robot arm handling crucible tray

Abstract

To provide crucible trays allowed to be stably picked up using a crucible holding part of a robot arm even when crucible trays vary in sizes.SOLUTION: A crucible tray is configured to receive a crucible C picked up or mounted on with a crucible holding part 10 which a robot arm device 31 has at its tip part, wherein hole parts 40a or through holes 50a in which a lower end parts of the crucible C are arranged in one or a plurality positions of upper surface side 1. A shape of the hole part 40a or the through hole 50a viewed from directly above is a generally droplet-like shape. When the number of these hole parts 40a or through holes 50a is plural, preferably, all of projection parts in a generally droplet-like shape arranged in a matrix state are oriented in a same direction.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a crucible tray on which a crucible is picked up or placed, and a control method for a robot arm device that handles a crucible using the crucible tray. [Background technology]

[0002] Dry metallurgy analysis is known as a method for quantitatively analyzing precious metal components such as gold and silver contained in ores. Dry metallurgy analysis is a quantitative analysis method in which a sample is prepared by mixing the ore to be analyzed with lead oxide and a flux, and then the sample is placed in a crucible, which is then loaded into a melting furnace and melted to dissolve the precious metals such as gold and silver into the lead and separate them from other metals, and the obtained alloy of the precious metal and lead is treated by cupellation to extract only the precious metal and measure its mass.

[0003] In the above-mentioned dry metallurgical analysis method, a crucible containing a sample is placed in a melting furnace, and the sample in the crucible is heated for a predetermined time at a temperature condition of, for example, about 1200°C until it is fully melted, and then the crucible is removed from the melting furnace and the high-temperature molten sample inside is quickly poured into a mold. Conventionally, this series of operations was manually performed by an operator using crucible tongs. Therefore, the operator had to work close to the melting furnace in a high-temperature environment, which placed a heavy burden on the operator, and various measures had to be taken to ensure safety.

[0004] Under such circumstances, in order to reduce the workload of the worker and to prevent safety problems, it has been proposed to automate the handling of the crucible during the dry metallurgical analysis, which has been done manually as described above. For example, Patent Document 1 discloses a tip holding means of a robot arm device that can pick up multiple crucibles from a predetermined location and place them in an aligned state on the mounting surface of a conveying means such as a belt conveyor. The tip holding means of this Patent Document 1 is made of a rectangular plate-like member having a through-hole that holds one or more crucibles, and the plate-like member is open on one side edge side extending in the longitudinal direction so that the crucible can be inserted and removed from the through-hole. As a result, for example, multiple crucibles can be placed on the mounting surface of a belt conveyor so as to be lined up in a row in the width direction, and multiple crucibles can be sequentially loaded into a heating furnace such as a melting furnace in a state where they are densely arranged on the mounting surface, thereby improving the processing capacity of the heating furnace. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2023-007212 A Summary of the Invention [Problem to be solved by the invention]

[0006] The robot arm device having the tip holding means as disclosed in the above Patent Document 1 repeats the operation of picking up a predetermined number of crucibles from a tray on which a plurality of crucibles are previously placed, and then placing the picked up crucibles on the placement surface of a conveying means such as a belt conveyor. In order to perform this operation stably, it is necessary that the plurality of crucibles are all placed in a state in which they are accurately positioned at a predetermined position on the tray. The reason is that if the crucibles are not accurately placed at a predetermined position on the tray, it will hinder the stable operation by the tip holding means, and there is a risk that the crucible will tip over when picking up or placing it, spilling the sample inside, or that the crucible will fall off the tip holding means while being transported by the robot arm device.

[0007] On the other hand, the crucibles handled by the tip holding means are not necessarily all the same size due to manufacturing tolerances and the like, and often have large variations in dimensions. In addition, since the crucibles are used repeatedly multiple times, they may be deformed by heating or the like. For example, as described above, an empty crucible immediately after the operation of pouring a high-temperature sample into a mold is larger in size than a crucible at room temperature due to thermal expansion. When handling multiple crucibles using a robot arm device, even if the crucibles have such variations in dimensions, it is required to stably repeat the operation of picking them up from a tray and placing them on the placement surface of the transport means.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a crucible tray that can be stably handled using the crucible holding portion of a robot arm device, even if the crucibles have dimensional variations. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the crucible tray of the present invention is a crucible tray that stores a crucible that is picked up or placed by a crucible holding part at the tip of a robot arm device, and is characterized in that a hole or through hole into which the lower end of the crucible is fitted is provided at one or more locations on the upper surface, and the shape of the hole or through hole when viewed from directly above is approximately teardrop-shaped with a part of a circle protruding.

[0010] A control method of a robot arm device according to the present invention is a control method of a robot arm device that handles a crucible in cooperation with a crucible holder provided at a tip end of the robot arm device and a crucible tray having a hole or through hole at one or more locations on an upper surface side into which a lower end of a crucible is fitted, the hole or through hole having a generally teardrop shape with a part of a circle protruding when viewed from directly above, the control method including a first step of picking up, with the crucible holder, a crucible that is placed in contact with two locations on the protruding part side of the generally teardrop shape of the hole or through hole of a first crucible tray; The method includes a second step of placing the crucible picked up in the first step on a loading surface on the upstream side of the heating furnace in a transport means that transports the crucible to a heating furnace, a third step of picking up the crucible placed on the loading surface on the downstream side of the heating furnace in the transport means, and a fourth step of discharging and emptying the contents of the crucible picked up in the third step, and then loading the emptied crucible into a hole or through-hole in a second crucible tray, and is characterized in that in the fourth step, after the crucible is placed, the crucible holder is moved horizontally to press the crucible against two points on the side of the approximately teardrop-shaped protruding portion. Effect of the Invention

[0011] According to the present invention, even if the crucible has a variation in size, it is possible to stably handle the crucible using the crucible holding portion of the robot arm device. [Brief description of the drawings]

[0012] [Figure 1]FIG. 11 is a plan view showing a state in which a robot arm device equipped with a crucible holding section is used to place multiple crucibles on a loading surface of a belt conveyor moving inside a heating furnace, and to pick up multiple crucibles from the loading surface. [Diagram 2] FIG. 1 is a perspective view showing a specific example of a robot arm device capable of placing and removing a crucible on the crucible tray of the present invention. [Diagram 3] 3 is a perspective view of a crucible holder provided at the tip of the robot arm device of FIG. 2. [Figure 4] 4A is a partial plan view of some of the through-holes of the crucible holding part of FIG. 3 as viewed from directly above, and FIG. 4B is a side view showing the positional relationship between the through-holes when the crucible is inserted into or removed from the through-hole. [Diagram 5] 4 is a perspective view showing a state in which six crucibles are held by the crucible holder of FIG. 3. FIG. [Figure 6] 6 is a side view showing a series of operations when six crucibles are placed simultaneously from the state shown in FIG. 5. FIG. [Figure 7] 4 is a side view showing a series of operations when the crucible is lifted up by using the crucible holding part of FIG. 3. [Figure 8] FIG. 11 is a perspective view showing a state in which six falling prevention means are aligned and placed on a placement table. [Figure 9] 4 is a side view showing a posture when the crucible holding part in FIG. 3 is rotated by 90 degrees or more to pour the contents from the crucible held in the penetration part. FIG. [Figure 10] 11 is a side view showing a series of operations in which the crucible holding part holding the crucible picks up the anti-fall means and then rotates to pour the contents of the crucible. FIG. [Figure 11] 13 is a perspective view showing a state in which six anti-falling means are aligned in a row on a mounting table by a comb-shaped alignment means equipped with an air cylinder. FIG. [Figure 12] FIG. 2 is a perspective view of one embodiment of a crucible tray of the present invention. [Figure 13] FIG. 13 is a cross-sectional view of the crucible tray of FIG. 12 taken along the line AA. [Figure 14]FIG. 2 is a perspective view of another embodiment of the crucible tray of the present invention. [Figure 15] 15 is a cross-sectional view of the crucible tray of FIG. 14 taken along the line BB. [Figure 16] 15 is a plan view of the hole portion of the crucible tray in FIG. 12 and the through hole of the crucible tray in FIG. 14 viewed from directly above. [Figure 17] 2A to 2C are plan views of various specific examples of holes or through holes in the crucible tray of the present invention. [Figure 18] 1 is a perspective view showing a state in which a crucible is placed on a crucible tray of one embodiment of the present invention using a crucible holding portion of a robot arm device. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the crucible tray according to the present invention will be described in detail with reference to the drawings. The crucible tray according to the embodiment of the present invention temporarily accommodates a crucible used when melting a sample prepared by mixing an ore with lead oxide and a flux in a melting device in order to quantitatively analyze precious metals such as gold and silver contained in the ore by dry metallurgical analysis. That is, the crucible tray according to the embodiment of the present invention is a tray used when picking up or placing a crucible by a robot arm device having a crucible holding part at the tip end capable of holding multiple crucibles, and even if the crucibles have different dimensions, they can be stably handled by cooperation with the robot arm device, and therefore the operation of picking up multiple crucibles and placing them on the placement surface of a conveying means such as a belt conveyor can be repeated without human intervention. This makes it possible to maximize the processing capacity of the melting device which melts the sample contained in the crucible.

[0014] 1. Melting equipment The melting device into which the crucibles picked up from the crucible tray of the embodiment of the present invention by the robot arm device having the crucible holder at its tip are loaded is generally composed of a conveying means for continuously or intermittently conveying the crucibles placed on the placement surface, and a melting furnace for heating and melting the contents of the crucibles as they are conveyed by the conveying means while passing through a tunnel-shaped furnace in sequence. There is no particular limitation on the specific type of the melting device, and it may be a type in which the crucibles conveyed by a conveying means running in one direction, such as a caterpillar belt conveyor, are passed through a tunnel-shaped melting furnace in sequence to be heated continuously, or a type in which the crucibles conveyed by rotating a circular or annular base around its central axis are passed through a tunnel-shaped melting furnace in sequence to be heated continuously. The former type of melting furnace is shown in FIG. 1.

[0015] 1 is composed of a belt conveyor 32 having an endless track, and the conveying path is configured so that the belt conveyor 32 enters through the charging port of the melting furnace 33, travels inside the melting furnace 33 in the right direction on the paper as indicated by the white arrow, and then exits through the exit on the opposite side of the charging port. On the conveyor surface of this conveying path, which is the crucible placement surface, the crucibles are placed one after another by the robot arm device 31 at the pre-charging crucible placement position 32a upstream of the charging port of the melting furnace 33. The placed crucible C is charged through the charging port of the melting furnace 33 by the continuous or intermittent running of the belt conveyor 32, and is heated inside the melting furnace 33 to melt the sample in the crucible C. The crucible C containing the sample melted in the melting furnace 33 exits the exit of the melting furnace 33 by continuous or intermittent transport on the belt conveyor 32, and is then transported to the post-exit crucible waiting position 32b downstream of the exit, where it is scooped up by the crucible holding portion 10 of the robot arm device 31.

[0016] 2.Robot arm device The operation of picking up a crucible from the crucible tray of the embodiment of the present invention and placing a crucible on the crucible tray is automatically performed by the crucible holder 10 of the robot arm device 31 as described above. That is, the crucible holder 10, which is also called an end effector provided at the tip of the robot arm device 31, can pick up a plurality of crucibles C containing samples, which are objects to be heated, from the crucible tray of the embodiment of the present invention and place them on the placement surface upstream of the melting furnace 33 on the belt conveyor 32 moving within the melting furnace 33. This crucible holder 10 can further scoop up a plurality of crucibles C containing heat-treated samples on the placement surface downstream of the melting furnace 33 on the belt conveyor 32, pour them into a mold, and then place the empty crucibles C on the crucible tray of the embodiment of the present invention.

[0017] As described above, in order to freely handle the crucible C by the crucible holding unit 10, it is preferable to use a robot with a vertical multi-joint structure, also called a manipulator, having the shape shown in FIG. 2, as the robot arm device 31. The robot arm device shown in FIG. 2 generally comprises a base unit 1 fixed to the floor surface with bolts or the like, a rotating unit 2 provided on the upper surface of the base unit 1 so as to be horizontally rotatable about the A1 axis, a vertical link unit (lower arm) 3 connected to the upper end of the rotating unit 2 so as to be rotatable back and forth about the A2 axis, a horizontal link unit (upper arm) 4 connected to the tip of the vertical link unit 3 so as to be rotatable up and down about the A3 axis, and a wrist unit 5 connected to the tip of the horizontal link unit 4 so as to be rotatable about the A4 axis. The wrist unit 5 is bent at its center around the A5 axis, and the crucible holding unit 10 is attached to its tip so as to be rotatable about the A6 axis.

[0018] 3. Crucible holding part The crucible holding part 10 provided at the tip of the robot arm device 31 is made of a rectangular plate-like member having six through-holes 11 capable of fitting and holding up to six crucibles C, as shown in Fig. 3, and is provided with a falling-out prevention means 20 to prevent up to six crucibles C held by the crucible holding part 10 from falling out of the through-holes 11. The six through-holes 11 are provided at equal intervals along the longitudinal direction of the rectangular plate-like member, and have an opening part in a shape in which one side edge (first side edge 10a) of both side edges extending in the longitudinal direction of the plate-like member is partially cut out so that the crucible C can be taken in and out from the first side edge 10a. This allows the robot arm device 31 to be operated to move the crucible holding portion 10 horizontally as a whole, so that up to six crucibles C held in the through-portion 11 of the crucible holding portion 10 can be passed through the open portion and placed simultaneously, or up to six crucibles C placed at predetermined positions can be picked up simultaneously by passing through the open portion.

[0019] By using the robot arm device 31 equipped with the crucible holder 10 having the above structure, it is possible to simultaneously scoop up to six crucibles C containing samples before heating that are placed on the crucible tray of the embodiment of the present invention, and then simultaneously place these six crucibles C on the loading surface of the belt conveyor 32 as a conveying means that runs continuously or intermittently, at a position upstream of the inlet of the melting furnace 33. In addition, it is possible to simultaneously scoop up to six crucibles C containing samples after heating that are waiting at a position downstream of the outlet of the melting furnace 33, and then incline the crucible holder 10 directly above the molds provided for each of these six crucibles C, thereby pouring the samples in each crucible C into the corresponding molds. The number of through-holes 11 provided on the crucible holder 10 is not limited to six. Furthermore, the shape of the crucible holding part 10 is not limited to a rectangular shape, but may be a rod shape or the like, so long as the individual crucibles C can be fitted into the through-holes and stably held therein.

[0020] As shown in Fig. 4(a), the inner diameter D of each of the six through-holes 11 of the crucible holder 10 is not particularly limited as long as the crucible C can be stably held in a fitted state, but since the crucible C has a shape that decreases in diameter toward the bottom, it is preferable that the inner diameter D is large enough to fit the outer diameter portion of the crucible C corresponding to a height H1 that is 60 to 70% of the total height H of the crucible C based on the lower end surface of the crucible C as shown in Fig. 4(b). In addition, the width W of the open part of each through-hole 11 shown in Fig. 4(a) is preferably large enough to pass the outer diameter portion of the crucible C corresponding to a height H2 that is 30 to 40% of the total height H so that insertion and removal can be performed at the outer diameter portion at a position lower than the outer diameter portion of the height H1. In addition, it is preferable that the inner wall surface of the approximately circular through-hole 11 has a smoothly curved convex shape when cut along any plane including the central axis of the through-hole 11 so that the side surface of the crucible C can be abutted along a line extending in the circumferential direction.

[0021] As shown in FIG. 5, when up to six crucibles C held in advance in six through holes 11 of the crucible holder 10 are simultaneously placed at a predetermined position on the placement surface of the conveying means, the robot arm device 31 first moves the crucible holder 10 to a position directly above a predetermined placement position on the placement surface S of the conveying means, and then lowers the crucible holder 10 directly below along the normal direction of the placement surface S to bring the lower end surface of the crucible C into contact with the placement surface S. At this time, the height of the center of the crucible holder 10 in the thickness direction from the placement surface S corresponds to the height H1 shown in FIG. 4(b). The crucible holder 10 is further lowered from the position of this height H1 so that the height of the center of the crucible holder 10 in the thickness direction from the placement surface S is equal to or less than the height H2 shown in FIG. 4(b). While maintaining this height, the crucible holder 10 is moved in a direction parallel to the mounting surface S and away from the crucible C, which is the left direction in the plane of the drawing in Figure 6. This completes the operation of simultaneously mounting up to six crucibles C at predetermined positions on the mounting surface S.

[0022] On the other hand, when using the crucible holding part 10 to simultaneously scoop up to six crucibles C placed at a predetermined position such as on the placement surface S of the transport means, the crucible holding part 10 may be operated using the robot arm device 31 in the reverse order to that shown in Fig. 6. Specifically, as shown in Fig. 7, first, while maintaining the front and back surfaces of the crucible holding part 10 approximately parallel to the placement surface S of the transport means, the robot arm device 31 moves the crucible holding part 10 to a position where the height of the center part in the thickness direction from the placement surface S is equal to or less than the height H2 shown in Fig. 4(b). At this time, the first side edge part 10a of the crucible holding part 10 faces the crucible C. By moving the crucible holder 10 closer to the crucible C while maintaining this position, up to six crucibles C are inserted into the six through-holes 11 provided on the first side edge 10a side through the openings of the six through-holes 11. When the six crucibles C have been inserted into the through-holes 11, the horizontal movement of the crucible holder 10 is stopped. Next, the crucible holder 10 is raised directly upward along the normal direction of the mounting surface S, so that the sides of the crucible C are entirely abutted against the inner peripheral edges of the through-holes 11. At this time, the height of the center of the crucible holder 10 in the thickness direction from the mounting surface S corresponds to H1 shown in FIG. 4(b). By further raising the crucible holding part 10, the operation of simultaneously scooping up up to six crucibles C by the crucible holding part 10 is completed.

[0023] Next, the robot arm device 31 moves the crucible holding part 10, which is holding up to six crucibles C as shown in Fig. 5 due to the completion of the above-mentioned scooping operation, toward the mounting table T on which the same number of falling prevention means 20 as the number of through-holes 11 possessed by the crucible holding part 10 are aligned and placed as shown in Fig. 8, and then picks up these falling prevention means 20 by the crucible holding part 10. At that time, as shown in Fig. 3, the approximately middle part of the arm part of the falling prevention means 20 described later is accommodated by the protrusion 12 which is provided on the crucible holding part 10 so as to protrude horizontally and has an approximately L-shape in a plan view. Specifically, the protrusion 12 protrudes horizontally in a direction perpendicular to the longitudinal direction of the crucible holding part 10 at a position corresponding to each of the through-holes 11 on the second side edge 10b side opposite to the first side edge 10a side where the open parts of the through-holes 11 are provided, and its tip is bent at a right angle to the horizontal direction and extends in the direction of the tip of the crucible holding part 10. As a result, a gap having a substantially rectangular shape in plan view is formed between the bent part of the protrusion 12 and the second side edge 10b of the crucible holding part 10, and the substantially middle part of the arm part described later, which is a component of the drop prevention means 20, can be accommodated in this gap. The substantially middle part of the arm part can be inserted and removed through the open part on the tip side of the crucible holding part 10 in this gap. In this way, by accommodating approximately the middle portion of the arm portion of the anti-falling means 20 in the gap formed by the protrusion 12, it is possible to prevent the anti-falling means 20 from shifting away from the crucible holding portion 10 or from wobbling significantly when the crucible holding portion 10 is moved by the robot arm device 31.

[0024] Next, the structure of the falling-off prevention means 20 will be described. As shown in Fig. 3, the falling-off prevention means 20 is composed of an arm portion 21, which is preferably made of two parallel rod-shaped members having a substantially inverted J-shape, and a weight portion 22 provided at the end of the arm portion 21. In this arm portion 21, the other end opposite to the end to which the weight portion 22 is connected is adapted to be hooked on the opening edge of the crucible C held by the crucible holding portion 10 when the robot arm device 31 lifts the crucible holding portion 10 to pick up the falling-off prevention means 20. Note that the arm portion 21 is not limited to the two rod-shaped members described above, and may be formed of one rod-shaped member, a long plate-shaped member, or the like, as long as it can be accommodated in the above-mentioned gap formed by the protruding portion 12 of the crucible holding portion 10.

[0025] With the above configuration, when the crucible holding part 10, together with up to six crucibles C held in its through-hole 11, is rotated approximately 90 to 120 degrees around an axis parallel to the longitudinal direction of the crucible holding part 10 as shown in Figure 9, the anti-fall-out means 20 which rotates together with the crucible holding part 10 functions as a balancer with the portion of its arm part 21 that abuts against the second side edge part 10b of the crucible holding part 10 as a fulcrum, thereby preventing the crucibles C from falling out of the through-hole 11.

[0026] More specifically, when the crucible C is tilted so as not to fall using the fall prevention means 20 picked up by the crucible holding part 10 holding the crucible C and the contents are discharged, the robot arm device 31 operates the crucible holding part 10 in the order of (a) to (e) shown in Fig. 10. That is, first, as shown by the white arrow in Fig. 10(a), the second side edge 10b side of the crucible holding part 10 holding the crucible C is abutted against or brought close to the group of arms 21 of the plurality of fall prevention means 20 placed in an aligned state on the placement table, and then the crucible holding part 10 is moved slightly toward its tip side, so that the approximately middle part of the arm part 21 is accommodated in the above-mentioned gap between the protrusion 12 provided on the second side edge 10b side of the crucible holding part 10 and the crucible holding part 10.

[0027] Next, as shown by the white arrow in Fig. 10(b), the crucible holding part 10 is raised directly upward along the normal direction to the mounting surface of the mounting table, and the entire falling prevention means 20 is lifted from the mounting table with the bent part at the tip of the arm part 21 having a generally inverted J-shape inserted into the opening edge part of the crucible C. In this state, the crucible holding part 10 holding the crucible C is moved together with the falling prevention means 20 to a location where the contents of the crucible C are to be discharged, for example, where molds are provided. Then, when up to six crucibles C held by the crucible holding part 10 are directly above the corresponding mold groups, the crucible holding part 10 is rotated about an axis parallel to its longitudinal direction as shown in Figs. 10(c) to (e). This allows up to six crucibles C held in the through-holes 11 of the crucible holder 10 to be tilted simultaneously, so that the samples contained therein can be poured into the group of molds, respectively.

[0028] Since the arm portion 21 is accommodated in the gap formed between the crucible holding portion 10 and its protruding portion 12 in a loosely fitted state, the fall-off prevention means 20 functions as a balancer when the crucible holding portion 10 rotates, i.e., functions like a balancer with weights attached to both ends of a horizontal bar. Specifically, when the crucible holding portion 10 rotates about 90 to 120 degrees, the crucible C, which is hooked at the other end by the weight portion 22 attached to one end of the arm portion 21 as a horizontal bar, is balanced like a balancer with the approximate middle portion of the arm portion 21 abutting against the second side edge portion 10b of the crucible holding portion 10 as a fulcrum, or at least functions so that a moment of upward rotation acts on the other end on the crucible C side when the crucible C becomes empty. This makes it possible to prevent the crucible C from falling off the penetration part 11 provided in the crucible holding part 10. After the content inside the crucible C is discharged, the crucible holding part 10 may be operated in the reverse order to the order shown in (a) to (e) of FIG.

[0029] As described above, the crucible holding part 10 has a plurality of through-holes 11 along its longitudinal direction, so that one or a plurality of crucibles C can be placed on a predetermined placement surface at the same time in a single operation, and one or a plurality of crucibles C can be simultaneously scooped up from the predetermined placement surface at the same time in a single operation. Furthermore, after the crucibles C are scooped up, the crucible holding part 10 can be rotated about an axis along its longitudinal direction, so that the molten contents can be simultaneously discharged from one or a plurality of crucibles C and poured into a plurality of molds, respectively.

[0030] Furthermore, the falling-off prevention means 20, whose moment is adjusted by the mass of the weight portion 22 and the horizontal distance from the weight portion 22 to the fulcrum when the hand is tilted to a predetermined angle, is attached to and detached from the crucible holding portion 10 before and after the above-mentioned discharge of the contents, so that the problem of the crucible C falling off from the penetration portion 11 can be prevented even when the crucible holding portion 10 is tilted, despite the extremely simple structure having no movable parts for gripping or holding the crucible C. Note that the adjustment of the moment is specifically made so that when the crucible C is tilted to an angle at which molten metal can be poured as shown in Fig. 9, the moment of gravity due to the weight portion 22 on the left side of the fulcrum on the paper becomes equal to or greater than the moment of gravity due to the crucible C on the right side of the fulcrum on the paper.

[0031] 4. Crucible tray As shown in FIG. 12, the crucible tray according to the embodiment of the present invention is a base 40 on which the crucible C picked up by the crucible holder 10 of the robot arm device 31 is accommodated, and a plurality of bottomed concave holes 40a into which the lower end of the crucible is fitted are provided on the upper surface side. In FIG. 12, the plurality of holes 40a are provided in a matrix shape overall, but this is not limited thereto, and a single row of holes may be provided, or only one hole may be provided. As shown in FIG. 13, since only the lower end of the crucible C is fitted into the hole 40a, a solid plate-like body having a thickness t of about 10 to 20 mm and made of metal, ceramic, resin, etc. can be used for the base 40.

[0032] The form of the crucible tray according to the embodiment of the present invention is not limited to the above-mentioned solid plate-like body as long as it can stably hold the crucible. For example, it may be a hollow metal box-like body, or as shown in FIG. 14, two thin metal plates 50 and 51 of the same size and substantially rectangular shape may be stacked with a space between them in the vertical direction, and these metal plates 50 and 51 may be joined together at least at four corners using metal pieces 52. By forming the crucible tray from a box-like body or two thin plates in this way, it is possible to reduce the weight. In addition, when forming the crucible tray from a box-like body or two thin plates, a through hole is provided only in the upper plate, and the crucible is supported by the lower plate. FIG. 15 shows a case where a through hole 50a is provided only in the upper metal plate 50. Regardless of the shape of the crucible tray, it is preferable that the crucible C is sufficiently fitted so that the crucible C does not easily fall over when the crucible tray is transported in a state in which the crucible C is fitted into the hole 40a or through hole 50a of the crucible tray. For this reason, it is preferable that the fitting depth d of the crucible shown in Figures 13 and 15 is about 5 to 15 mm.

[0033] In the crucible tray according to the embodiment of the present invention, regardless of the above-mentioned configuration, the hole 40a or the through hole 50a has a generally teardrop shape with a part of a circle protruding in a V-shape when viewed from directly above. Since the hole 40a or the through hole 50a has such a characteristic shape, even if the dimensions of the crucible C vary, the crucible C can always be accurately placed in the same position on the crucible tray.

[0034] 16, the hole 40a and the through hole 50a are generally teardrop-shaped when viewed from directly above, except for the acute angle range θ, and the majority of the hole 40a and the through hole 50a are arc-shaped with a radius r centered on the center point O, and in the angle range θ, two line segments l1 and l2 extending tangentially from both ends p and q of the arc-shaped portion intersect at one point to form a V-shaped protrusion. The inner diameter of this arc-shaped portion (i.e., 2r) is larger than the intermediate outer diameter a of the crucible C at the same height as the upper surface of the crucible tray when the crucible C is placed on the crucible tray, so that a gap is generated between the crucible C and the outer wall of the crucible C when the crucible C is placed on the crucible tray.

[0035] There is no particular limitation on how large the inner diameter 2r of the arc-shaped portion is to be relative to the intermediate outer diameter a of the crucible C, as long as the holes 40a and through holes 50a can be provided at the same pitch as the multiple through holes 11 provided in the crucible holding part 10 of the robot arm device 31 described above, but considering the variation in the outer diameter dimension of the crucible C and the thermal deformation that occurs when the crucible C is used repeatedly multiple times, it is preferable that the size of the gap G that occurs on the opposite side to the protruding part side when the crucible C is placed in a state in which the outer wall of the approximately teardrop-shaped V-shaped protruding part side is abutted against the hole part 40a or through hole 50a of the crucible tray is about 5 to 10 mm. If the size of the gap G is within this range, the crucible C can be smoothly placed and picked up by the robot arm device 31.

[0036] In the crucible tray according to the embodiment of the present invention, when the crucible C is fitted into the hole 40a or the through hole 50a as described above, the outer wall of the crucible C is brought into contact with two points on the V-shaped protruding portion side of the approximately teardrop shape, so that the crucible C can always be positioned at the same position when the crucible C is placed in the hole 40a or the through hole 50a in a fitted state. This makes it possible for the robot arm device 31 to stably pick up the crucible C. This makes it difficult to cause problems such as the crucible C tipping over by the robot arm device 31, which is a problem when using a conventional tray having a hole or through hole that is simply circular and has an outer diameter larger than the intermediate outer diameter a of the crucible C.

[0037] In the above-mentioned teardrop-like shape, as long as the outer wall of the crucible C can be stably supported at two points on the V-shaped protruding portion side, there is no particular limitation on the length of the two line segments l1 and l2 or the angle range θ between the positions p and q of the ends of these two straight lines l1 and l2, but this angle range θ is preferably about 45 to 90 degrees, and more preferably about 60 degrees. In the crucible tray of the above-mentioned embodiment of the present invention, the V-shaped protruding portion has been described on the premise that it is composed of two straight lines l1 and l2, but as long as the crucible C can always be positioned at the same position, the V-shaped protruding portion is not limited to being composed of straight lines. For example, instead of straight lines, the hole portion 140a and the through hole 150a in FIG. 17(a) may be curved inward. Alternatively, the tip of the protruding portion may be smoothly curved as in the hole 240a and through hole 250a in FIG. 17(b), or the tip of the protruding portion may be flat as in the hole 340a and through hole 350a in FIG. 17(c). In either case, when the crucible C is placed with the outer wall abutting against two points of the radially protruding portion as described above, it is necessary that a gap G is secured on the side opposite to the protruding portion. If the gap G is not secured in this portion, it will be impossible to fit the crucible C into the hole 40a or through hole 50a or to remove the crucible C from the hole 40a or through hole 50a.

[0038] In the above description, the case where the crucible tray is used when the robot arm device 31 picks up the crucible is described, but the present invention is not limited to this case, and the crucible tray of the embodiment of the present invention may be used when picking up the crucible containing the molten sample from the melting furnace and placing the empty crucible after pouring the sample into the mold. In this case, it is preferable to place the crucible C held by the crucible holder 10 of the robot arm device 31 on the crucible tray, and then slightly move the crucible holder 10 in the horizontal direction as shown by the black arrow in Fig. 18 to press the outer wall of the crucible C against two points on the V-shaped protruding portion side of the hole 40a or the through hole 50a in the above-mentioned approximately teardrop shape. This allows the empty crucible C placed on the crucible tray to be stably handled when scooped up again by the crucible holding portion 10 of the robot arm device 31.

[0039] As described above, the crucible tray of the embodiment of the present invention allows the crucible to always be placed in the same position when the robot arm device picks up a crucible containing contents before processing, or when the robot arm device places an empty crucible after processing. Therefore, even if there is variation in the dimensions of the crucible, it is possible for the robot arm device 31 to handle the crucible stably without causing problems such as the crucible tipping over.

[0040] 4. Control method of robot arm device for handling crucible Next, a control method for the robot arm device 31 according to the embodiment of the present invention, which handles the crucible C using the crucible holder and the crucible tray, will be described. The control method of the robot arm device 31 of this embodiment of the present invention includes a first step of scooping up multiple crucibles C containing samples before heat treatment from a first crucible tray, a second step of placing the crucibles C picked up in the first step on a conveyor surface that is the upstream loading surface of the melting furnace 33, which is a type of heating furnace, on a belt conveyor serving as a transport means for transporting the crucibles C to the melting furnace 33, which is a type of heating furnace, a third step of scooping up multiple crucibles C containing molten samples after heat treatment from the conveyor surface that is the downstream loading surface of the belt conveyor from the melting furnace 33, and a fourth step of discharging the molten samples from the crucibles C picked up in the third step to empty them, and then placing the empty crucibles C on a second crucible tray different from the above. A series of these steps is repeatedly performed using one robot arm device 31. The control method of the robot arm device 31 is performed by the controller 6 that the robot arm device 31 has.

[0041] To explain in more detail, first, the robot arm device 31 is operated so that the crucible holding part 10 attached to the tip of the robot arm device 31 is used to scoop up six of the crucibles C placed on the first crucible tray and hold them at the penetration part 11. Then, by performing the series of operations shown in FIG. 6 described above, these six crucibles C are simultaneously placed on the conveyor surface of the belt conveyor 32 at the pre-loading crucible placement position 32a upstream of the loading entrance of the melting furnace 33, as shown by the solid line in FIG. 1.

[0042] When the robot arm device 31 picks up the crucible C, each crucible C is fitted in the teardrop-shaped hole 40a of the crucible tray in a state of abutting two points on the V-shaped protruding portion side, so that even if there is dimensional variation in the crucible C due to allowable dimensional tolerance variation during manufacture or thermal deformation due to repeated use, it is possible to always accurately position the crucible C in the same position. This makes it less likely that the crucible holder 10 will be unable to pick up the crucible C or that the crucible C will tip over. In addition, when the crucible C picked up by the crucible holding part 10 is placed on the conveyor surface, it is preferable that the longitudinal direction of the crucible holding part 10 is parallel to the width direction of the belt conveyor 32, and that the first side edge 10a side having the open portion of the through portion 11, among the both side edges extending in the longitudinal direction of the crucible holding part 10, is positioned facing the melting furnace 33.

[0043] The six crucibles C thus simultaneously placed on the pre-loading crucible placement position 32a of the belt conveyor 32 are loaded into the melting furnace 33 by the continuous or intermittent running of the belt conveyor 32, where the samples in the crucibles C are subjected to heat treatment under predetermined temperature conditions. The six crucibles C containing the samples that have been molten by this heat treatment exit the exit of the melting furnace 33 by the continuous or intermittent running of the belt conveyor 32, and are then transported on the conveyor surface of the belt conveyor 32 to the crucible standby position 32b after exiting the exit.

[0044] When the six crucibles C waiting in a row in the width direction of the belt conveyor 32 at the crucible waiting position 32b after the exit are simultaneously scooped up by the crucible holding part 10 of the robot arm device 31, the crucible holding part 10 may be moved in the order shown by the white arrows in Fig. 7. At that time, it is preferable that the crucible holding part 10 is in a position in which its longitudinal direction is parallel to the width direction of the belt conveyor 32, and the second side edge part 10b opposite to the first side edge part 10a having the opening part of the through part 11 faces the melting furnace 33, as shown by the dashed line in Fig. 1. After the six crucibles C are simultaneously scooped up from the conveyor surface, the crucible holding part is moved by the robot arm device 31 in the order shown in (a) to (e) of Fig. 10, so that the molten sample is poured into a mold (not shown).

[0045] Specifically, first, in Figure 10(a), the second side edge 10b of the crucible holding part 10 is brought close to the arm portions 21 of multiple anti-falling means 20 that are aligned in a row on the mounting table, and then the crucible holding part 10 is moved horizontally toward its tip side so that approximately the middle portions of the multiple arm portions 21 are inserted from their open sides into multiple gaps between the second side edge 10b and multiple approximately L-shaped protrusions 12 provided on the second side edge 10b side of the crucible holding part 10.

[0046] 10(b), the crucible holding part 10 is moved directly upward from the mounting surface of the mounting table T, so that the bent part formed at the tip of the arm part 21 having an inverted J shape is inserted into the corresponding opening edge of the crucible C. This causes the tip to hook onto the opening edge of the crucible C. By further moving the crucible holding part 10 upward in this state, the falling prevention means 20 is lifted by the crucible holding part 10.

[0047] Next, the crucible holder 10, which has been lifted together with the fall-prevention means 20 in the above manner, is moved to a location where multiple molds are lined up in a row, and the crucible holder 10 is rotated about an axis extending in its longitudinal direction while the crucible C is held by the multiple through holes 11 of the crucible holder 10 in the order of Figures 10(c) to 10(e). This allows the crucible C to be tilted so that its opening faces diagonally downward, allowing the molten sample to be poured into multiple molds (not shown) at once.

[0048] The falling prevention means 20 adjusts the mass of the weight part 22 and the horizontal distance between the weight part 22 and the fulcrum when the crucible C is tilted to a predetermined angle at which molten metal can be poured, so that the gravity moment on the weight part 22 side with the fulcrum as a boundary when the crucible holding part 10 rotates is equal to or greater than the gravity moment on the crucible C side with the fulcrum as a boundary. This allows the crucible C to be stably poured without falling off the crucible holding part 10 not only when the crucible C is in a horizontal position tilted by 90 degrees, but also when the crucible C is in a position tilted by more than 90 degrees to about 120 degrees. After the above pouring is completed, the crucible holding part 10 is moved in the reverse order to the order of Figs. 10(a) to (e) described above, and the falling prevention means 20 can be returned to its original position on the mounting table T.

[0049] Incidentally, as shown in Fig. 10(a), when the crucible holder 10 picks up the multiple fall-prevention means 20 on the mounting table, it is preferable to align the multiple fall-prevention means 20 in a row at equal intervals in accordance with the pitch of the multiple protrusions 12 of the crucible holder 10. In addition, as shown in Fig. 10(b), it is preferable to lock the fall-prevention means 20 so that it does not move on the mounting table T until it is lifted by the crucible holder 10. Therefore, as shown in Fig. 11, it is preferable to use an alignment means 23 having a shape in which multiple rectangular protrusions are provided at equal intervals in a comb shape on one side of a substantially rectangular plate-like body extending in the longitudinal direction, to store the multiple fall-prevention means 20 between the adjacent rectangular protrusions, thereby making the multiple fall-prevention means 20 wait in a row aligned on the mounting table. In this case, by matching the pitch of the multiple rectangular protrusions of the alignment means 23 with the pitch of the multiple through holes 11 of the crucible holding part 10, the falling-off prevention means 20 can be picked up simply by moving the crucible holding part 10 of the robot arm device 31 in the horizontal direction as shown in Fig. 10(a). It is preferable to form the interval between adjacent rectangular protrusions to be slightly wider than the width of the weight part 22 so that the falling-off prevention means 20 aligned by the alignment means 23 can be easily picked up by the crucible holding part 10.

[0050] After the molten sample in the crucible C is poured into the mold, the falling-off prevention means 20 is returned to the alignment means 23 on the mounting table by operating the crucible holding part 10 in the reverse order of Figures 10(a) to (e) as described above. At this time, it is preferable to push the weight part 22 until it abuts against the back of the space between the adjacent rectangular protrusions using a pushing means 24 such as an air cylinder so that the weight part 22 fits securely between the adjacent rectangular protrusions. This makes it possible for the crucible holding part 10 to pick up the multiple falling-off prevention means 20 more reliably.

[0051] Next, the crucible holder 10, with the six crucibles C emptied after the samples are discharged and held in the through-hole 11, is moved to a different crucible tray from the one used when the crucibles C containing the samples were picked up, and the six empty crucibles C are placed in the holes 40a by moving the crucible holder 10 in the order shown in Fig. 6. Of the series of movements shown by the white arrows in Fig. 6, it is preferable to move the crucible holder 10 in the direction opposite to the direction of separation from the crucible C facing left on the paper, as shown by the black arrow in Fig. 18, to press the outer wall of the crucible C against the V-shaped protruding portion of the approximately teardrop shape of the hole 40a or the through-hole 50a. As a result, the outer wall of the crucible C is supported at two points on the V-shaped protruding portion side, so that it is possible to always accurately position the crucible C at the same position even if there is dimensional variation in the crucible C. In this way, by placing unheated samples again into the crucibles C on the crucible tray on which the empty crucibles C are placed, the crucibles C can be repeatedly handled as crucibles C containing samples to be picked up by the robot arm device 31 described above. [Explanation of symbols]

[0052] 1 Base 2 Swivel section 3 Vertical link section 4. Horizontal link 5 Wrist part 6 Controller 10 Crucible holding part 10a 1st side edge 10b 2nd side edge 11 Penetration 12 Protrusion 20 Fall prevention means 21 Arm section 22 Weight section 23 Alignment means 24 Pushing means 31 Robot arm device 32 Conveyor Belt 32a Crucible placement position before charging 32b Crucible standby position after exit 33 Melting Furnace 40 Foundations 40a Hole 50, 51 Metal plate material 50a through hole 52 Metal piece A1, A2, A3, A4, A5, A6 rotation axis C Crucible D Inner diameter G Gap H Total height of crucible S Placement surface T mounting table W Width of the open part

Claims

1. A crucible tray for accommodating a crucible to be picked up or placed by a crucible holder at the tip of a robot arm device, A crucible tray having a hole or through hole in one or more places on the upper surface into which the lower end of the crucible is fitted, and the shape of the hole or through hole when viewed from directly above is approximately teardrop-shaped with a portion of a circle protruding.

2. 2. The crucible tray according to claim 1, wherein the number of holes or through holes provided on the upper surface side is multiple, the multiple holes or through holes are arranged in a matrix, and all of the protruding portions of the approximately teardrop shape face in the same direction.

3. A method for controlling a robot arm device, which handles a crucible in cooperation with a crucible holder at a tip end of the robot arm device and a crucible tray having a hole or through hole at one or more locations on an upper surface side into which a lower end of the crucible is fitted, the hole or through hole having a generally teardrop shape with a part of a circle protruding when viewed from directly above, a second step of placing the crucible picked up in the first step on a placement surface on the upstream side of the heating furnace in a transport means that transports the crucible picked up in the first step to a heating furnace; a third step of picking up the crucible that is placed on a placement surface on the downstream side of the heating furnace in the transport means; and a fourth step of discharging the contents of the crucible picked up in the third step to empty it, and then placing the emptied crucible in the hole or through hole of a second crucible tray, wherein in the fourth step, the crucible is pressed against the two places on the approximately teardrop-shaped protruding portion by moving the crucible holding part in a horizontal direction after placing the crucible.

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