Robot hand and robot

Abstract

To provide technique enabling suppression of such a problem that the malfunction of a robot hand occurs due to increase of temperature of a hand arm part to high temperature.SOLUTION: A robot hand holds a sagger carried out from a heat treatment furnace. The robot hand comprises a hand arm part which holds the sagger and a cooling mechanism which cools the hand arm part. A robot comprises a robot arms and robot hands which are mounted to the robot arms and hold the sagger carried out from the heat treatment furnace.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The technology disclosed in this specification relates to a robot hand and a robot.

Background Art

[0002] Patent Document 1 discloses a robot hand. After the crucible is carried out from the heat treatment furnace, the robot hand grips the crucible using the hand arm portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above robot hand, the high-temperature crucible is gripped by the hand arm portion. As a result, the hand arm portion becomes high temperature, and malfunction of the robot hand may occur.

[0005] This specification discloses a technology capable of suppressing the occurrence of malfunction of the robot hand due to the hand arm portion becoming high temperature.

Means for Solving the Problems

[0006] In a first aspect of the technology disclosed in this specification, the robot hand grips a crucible carried out from a heat treatment furnace. The robot hand includes a hand arm portion that grips the crucible and a cooling mechanism that cools the hand arm portion.

[0007] With the above configuration, the hand arm is cooled by the cooling mechanism. This prevents the hand arm from becoming overheated even when gripping a hot saggar. This helps to prevent malfunctions in the robot hand.

[0008] In a tenth aspect of the technology disclosed herein, the robot comprises a robotic arm and a robotic hand attached to the robotic arm for grasping a saggar removed from a heat treatment furnace. The robotic hand comprises a hand arm portion for grasping the saggar and a cooling mechanism for cooling the hand arm portion.

[0009] The above configuration can produce effects similar to those of the robotic hand described above. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view of the heat treatment system according to the first embodiment. [Figure 2] This is a schematic diagram of the heat treatment system of the first embodiment. [Figure 3] This is a perspective view of the robot hand of the first embodiment. [Figure 4] This is a perspective view of the right hand arm of the robot hand according to the first embodiment. [Figure 5] This is a cross-sectional view of the first right hand arm, the left hand arm, and the cooling mechanism when the first right gripping member, the second right gripping member, the first left gripping member, and the second left gripping member are in the second position in the first embodiment. [Figure 6] This is a perspective view of the left hand arm of the robot hand according to the first embodiment. [Figure 7] This is a cross-sectional view of the first right hand arm, the left hand arm, and the cooling mechanism when the first right gripping member, the second right gripping member, the first left gripping member, and the second left gripping member are in the first position in the first embodiment. [Figure 8] This is a cross-sectional view of the sagger and hand arm when the shutter is in the open position in the first embodiment. [Figure 9] In the first embodiment, it is a cross-sectional view of the crucible and the hand arm when the shutter is in the closed position. [Figure 10] It is a top view of the crucible and the hand arm after the preparation process in the first embodiment. [Figure 11] It is a top view of the crucible and the hand arm after the first gripping process or the second gripping process in the first embodiment. [Figure 12] It is a side view of the crucible and the hand arm after the first gripping process or the second gripping process in the first embodiment. [Figure 13] It is a side view of the crucible and the hand arm after the lifting process in the first embodiment. [Figure 14] It is a side view of the crucible and the hand arm after the positioning process in the first embodiment. [Figure 15] It is a side view of the crucible and the hand arm after the first inversion process in the first embodiment. [Figure 16] It is a side view of the crucible and the hand arm after the second movement process in the first embodiment. [Figure 17] It is a side view of the crucible and the hand arm after the gripping release process in the first embodiment. [Figure 18] It is a side view of the crucible and the hand arm after the first gripping process in the second embodiment. [Figure 19] It is a top view of the hand arm in the second embodiment. <00000⑧6>In the second embodiment, it is a side view of the crucible and the hand arm before the second right pressing member, the third right pressing member, the second left pressing member, and the third left pressing member move in the positioning process. [Figure 21] It is a side view of the crucible and the hand arm after the positioning process in the second embodiment.

Mode for Carrying Out the Invention

[0011] List the main features of the embodiments described below. Note that the technical elements described below are each independent technical elements, which exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

[0012] In the second aspect of the technology disclosed in this specification, in the above first aspect, the cooling mechanism is provided in the hand arm portion. According to the above configuration, it is possible to further suppress the hand arm portion from becoming high temperature.

[0013] In the third aspect of the technology disclosed in this specification, in the above first or second aspect, the hand arm portion includes a hand arm having a first opening, a second opening, and an internal space. The cooling mechanism is attached to the first opening, and includes a supply device that supplies fluid to the internal space through the first opening and discharges the fluid from the second opening. According to the above configuration, the fluid flows into the internal space from the first opening, passes through the internal space, and is then discharged to the outside of the hand arm portion from the second opening. Thereby, the cooling efficiency of the hand arm portion can be enhanced.

[0014] In the fourth aspect of the technology disclosed in this specification, in the above third aspect, the hand arm portion further includes a contact member that contacts the sagger when gripping the sagger. The hand arm includes a first wall to which the contact member is attached, and a second wall different from the first wall and in which the first opening is disposed. According to the above configuration, it is possible to suppress the supply device attached to the first opening from interfering with the sagger.

[0015] In the fifth aspect of the technology disclosed in this specification, in the above fourth aspect, the supply device is attached to the second opening. The second opening is disposed in the second wall. According to the above configuration, it is possible to further suppress the supply device from interfering with the sagger.

[0016] In a sixth aspect of the technology disclosed herein, in any one of the third to fifth aspects described above, the fluid is a cooling gas or compressed air. With the above configuration, it is possible to suppress the hand arm from becoming hot with a simple configuration.

[0017] In a seventh aspect of the technology disclosed herein, in any one of the first to sixth aspects described above, the robot hand further comprises a base portion that supports the hand arm portion, and a mounting member that allows the base portion to be attached to the robot arm. The thermal conductivity of the mounting member is lower than that of the base portion. With the above configuration, it is possible to suppress the transfer of heat from the hand arm portion to the robot arm.

[0018] In an eighth aspect of the technology disclosed herein, the robot hand further comprises, in the seventh aspect described above, a heat shield member disposed between the sagger and the base when the sagger is gripped by the hand arm. With the above configuration, it is possible to suppress the direct transfer of heat from the sagger to the base.

[0019] In a ninth aspect of the technology disclosed herein, the heat shielding member is attached to the base portion in the eighth aspect described above. With this configuration, it is possible to prevent the heat shielding member from shifting away from the gap between the sagger and the base portion.

[0020] (First embodiment) As shown in Figure 1, the heat treatment system 10 includes a heat treatment furnace 12, a conveying device 14, a robot 16, and a control device 18.

[0021] The heat treatment furnace 12 heat-treats the object to be treated 4 (see Figure 10) in the sagger 2. The sagger 2 has a box shape that is roughly rectangular with an open top. The sagger 2 is equipped with a plurality of notches 2a. The notches 2a are located on each of the four side walls of the sagger 2. Two of the notches 2a face each other, and the remaining two notches 2a face each other. The notches 2a are located at the top of the sagger 2. The notches 2a communicate the inside and outside of the sagger 2. The plurality of saggers 2 are stacked vertically. The plurality of saggers 2 are placed on a base plate 8 via spacers 6. Therefore, the sagger 2 located at the bottom of the stacked plurality of saggers 2 is away from the base plate 8 and does not come into contact with the base plate 8. The material to be processed 4 is, for example, a raw material for a ceramic capacitor, or a positive or negative electrode material for a lithium-ion battery.

[0022] The heat treatment furnace 12 is a thermal insulation structure with a roughly rectangular parallelepiped shape. The heat treatment furnace 12 has an inlet 20, an outlet 22 opposite the inlet 20, and a heat treatment space 24. The heat treatment space 24 is in communication with the outside space of the heat treatment furnace 12 via the inlet 20 and the outlet 22.

[0023] The conveying device 14 includes a guide member 28 and a pusher 30. The guide member 28 is positioned across the heat treatment space 24 and the space outside the heat treatment furnace 12. The base plate 8 is placed on the guide member 28. The pusher 30 is configured to press the base plate 8 on the guide member 28. By repeatedly pressing the base plate 8 under the control of the control device 18, the pusher 30 moves guided by the guide member 28. As a result, the sagger 2 and the base plate 8 are transported from the space outside the heat treatment furnace 12 to the heat treatment space 24 via the entrance 20, and after passing through the heat treatment space 24, are transported from the heat treatment space 24 to the space outside the heat treatment furnace 12 via the exit 22. The object to be treated 4 in the sagger 2 is fired, i.e., heat treated, by a heater (not shown) in the heat treatment space 24 while passing through the heat treatment space 24.

[0024] The robot 16 is positioned in the space outside the heat treatment furnace 12. The robot 16 is positioned near the discharge port 22. As shown in Figure 2, the robot 16 grasps the sagger 2 that has been discharged from the discharge port 22 and collects the heat-treated material 4 inside the sagger 2 into the recovery container 34. The control device 18 controls the robot 16 based on the position and orientation of the sagger 2 detected by the sagger detection device 36. The sagger detection device 36 is, for example, a camera.

[0025] Robot 16 is a multi-joint robot. Robot 16 comprises a base 40, a robot arm 42, and a robot hand 44. The robot arm 42 is mounted on the base 40. The robot arm 42 is, for example, a 6-axis multi-joint robot arm. The robot arm 42 is rotatable around axis AX1 extending in the vertical direction, around axis AX2 which is substantially perpendicular to the vertical direction, around axis AX3 which is substantially perpendicular to the vertical direction, around axis AX4 which is substantially perpendicular to axis AX3, around axis AX5 which is substantially perpendicular to the vertical direction, and around axis AX6 which is substantially perpendicular to axis AX5. By rotating the robot arm 42, the position and orientation of the robot hand 44 are adjusted. Note that the axes on which the robot arm 42 rotates are not limited to the above configuration.

[0026] The robot hand 44 is attached to the tip of the robot arm 42. The robot hand 44 grasps the sagger 2. As shown in Figure 3, the robot hand 44 comprises a base portion 48, a mounting member 50, a heat shielding member 52, and a pair of hand arm portions 54 and 56. In the following description of the robot hand 44, the direction in which the hand arm portions 54 and 56 extend will be called the front-rear direction, the direction perpendicular to the front-rear direction will be called the up-down direction, and the direction perpendicular to both the front-rear direction and the up-down direction will be called the left-right direction.

[0027] The base portion 48 comprises an arm support member 64 and a frame member 66. The arm support member 64 supports a pair of hand arm portions 54, 56. The arm support member 64 is made of, for example, a metal material. The arm support member 64 extends in the left-right direction.

[0028] The frame member 66 is attached to the upper end of the arm support member 64. The frame member 66 is made of, for example, a metal material. The metal material is, for example, aluminum. The frame member 66 has a hollow shape. Therefore, the frame member 66 can be made lighter compared to a configuration in which the frame member 66 does not have a hollow shape.

[0029] The mounting member 50 is attached to the rear end of the frame member 66. The mounting member 50 allows the frame member 66 to be attached to the tip of the robot arm 42 (see Figure 2). The mounting member 50 is positioned between the frame member 66 and the robot arm 42. The mounting member 50 is made of, for example, a cement-based material or a calcium silicate-based material. The thermal conductivity of the mounting member 50 is lower than the thermal conductivity of the arm support member 64 and the frame member 66 (i.e., lower than the thermal conductivity of the base portion 48). This prevents heat from the sagger 2 from being transferred from the base portion 48 to the robot arm 42 via the mounting member 50. The mounting member 50 may include a metal member and an insulating sheet sandwiched between the metal member and the tip of the robot arm 42.

[0030] The heat shielding member 52 is attached to the front end of the arm support member 64 and the front end of the frame member 66. The heat shielding member 52 has a plate shape. The heat shielding member 52 is made of, for example, a metal material. The metal material is, for example, stainless steel. When the robot hand 44 is gripping the sagger 2 (see Figure 2), the heat shielding member 52 is positioned between the sagger 2 and the arm support member 64, and away from the sagger 2. This suppresses the transfer of radiant heat from the sagger 2 to the arm support member 64 and the frame member 66. The heat shielding member 52 may comprise a metal member and an insulating material placed on the surface of the metal member facing the sagger 2.

[0031] The pair of hand arm sections 54 and 56 comprises a right hand arm section 54 and a left hand arm section 56. The right hand arm section 54 and the left hand arm section 56 are spaced apart in the left-right direction. The right hand arm section 54 is symmetrical with respect to the left hand arm section 56 with respect to a virtual plane P1. The virtual plane P1 is a plane that includes the vertical and horizontal directions and passes through the left-right center of the robot hand 44.

[0032] As shown in Figure 4, the right hand arm section 54 includes a right hand arm 70, a first right gripping member 72, a second right gripping member 74, a first right claw 76, a second right claw 78, a first right pressing member 80, and a second right pressing member 82.

[0033] The right hand arm 70 is made of, for example, a metal material. This increases the strength of the right hand arm 70. The metal material is, for example, stainless steel or aluminum. The right hand arm 70 has a substantially rectangular parallelepiped shape. The right hand arm 70 extends forward from the arm support member 64. The right hand arm 70 is movable in the left-right direction relative to the arm support member 64. The right hand arm 70 is moved by the control of an arm drive device (not shown) by a control device 18 (see Figure 2).

[0034] As shown in Figure 5, the right hand arm 70 has a hollow shape. The right hand arm 70 has a first opening 86, a second opening 88, and an internal space 90. The first opening 86 and the second opening 88 are located in the rear wall 70a of the right hand arm 70. The first opening 86 and the second opening 88 penetrate the rear wall 70a. The first opening 86 and the second opening 88 are spaced apart in the vertical direction. The internal space 90 communicates with the first opening 86 and the second opening 88.

[0035] As shown in Figure 4, the first right gripping member 72 and the second right gripping member 74 are made of, for example, ceramics. The ceramics are, for example, oxide-based ceramics or non-oxide-based ceramics. The first right gripping member 72 and the second right gripping member 74 are attached to the left wall 70b of the right hand arm 70. The first right gripping member 72 and the second right gripping member 74 have a substantially rectangular parallelepiped shape. The first right gripping member 72 and the second right gripping member 74 are spaced apart in the front-rear direction.

[0036] The first right claw 76 is made of, for example, ceramics. The ceramics are, for example, oxide ceramics or non-oxide ceramics. The first right claw 76 is attached to the upper wall 70c of the right hand arm 70. The first right claw 76 protrudes to the left from the upper wall 70c, beyond the left wall 70b. The first right claw 76 is positioned above the first right gripping member 72 and the second right gripping member 74.

[0037] The second right claw 78 is made of, for example, ceramics. The ceramics are, for example, oxide ceramics or non-oxide ceramics. The second right claw 78 is attached to the lower wall 70d of the right hand arm 70. The second right claw 78 protrudes to the left from the lower wall 70d, beyond the left wall 70b. The second right claw 78 is positioned below the first right gripping member 72 and the second right gripping member 74. The first right gripping member 72 and the second right gripping member 74 are positioned vertically between the first right claw 76 and the second right claw 78. The second right claw 78 is positioned vertically spaced apart from the first right claw 76. The length of the first right claw 76 protruding from the left wall 70b is shorter than the length of the second right claw 78 protruding from the left wall 70b.

[0038] The first right pressing member 80 and the second right pressing member 82 are made of, for example, ceramics. The ceramics are, for example, oxide ceramics or non-oxide ceramics. The first right pressing member 80 and the second right pressing member 82 are attached to the left wall 70b of the right hand arm 70. The first right pressing member 80 is rotatable around a pivot axis AX10 that extends in the left-right direction. The first right pressing member 80 rotates between a first position and a second position. The second right pressing member 82 is rotatable around a pivot axis AX11 that extends in the left-right direction. The pivot axis AX10 is substantially parallel to the pivot axis AX11. The second right pressing member 82 rotates between a first position and a second position. The first right pressing member 80 is positioned at a distance from the second right pressing member 82 in the front-rear direction. The first right pressing member 80 is positioned in front of the second right pressing member 82. In the front-rear direction, the first right gripping member 72, the second right gripping member 74, the first right claw 76, and the second right claw 78 are positioned between the first right pressing member 80 and the second right pressing member 82.

[0039] The first right pressing member 80 has a substantially L-shape. The first right pressing member 80 comprises a first contact portion 94 and a second contact portion 96. The first contact portion 94 is rotatably attached to the left wall 70b of the right hand arm 70. The second contact portion 96 protrudes from the lower end of the first contact portion 94 in a direction toward the second right pressing member 82. The second contact portion 96 is substantially perpendicular to the first contact portion 94.

[0040] The second right pressing member 82 has a substantially L-shape. The second right pressing member 82 comprises a first contact portion 100 and a second contact portion 102. The second contact portion 102 is rotatably attached to the left wall 70b of the right hand arm 70. The second contact portion 102 protrudes from the lower end of the first contact portion 100 in a direction toward the first right pressing member 80. The second contact portion 102 is substantially perpendicular to the first contact portion 100.

[0041] As shown in Figure 6, the left hand arm section 56 comprises a left hand arm 110, a first left gripping member 112, a second left gripping member 114, a first left claw 116, a second left claw 118, a first left pressing member 120, and a second left pressing member 122. Each of the left hand arm 110, the first left gripping member 112, the second left gripping member 114, the first left claw 116, the second left claw 118, the first left pressing member 120, and the second left pressing member 122 is positioned at a distance in the left-right direction from each of the right hand arm 70, the first right gripping member 72, the second right gripping member 74, the first right claw 76, the second right claw 78, the first right pressing member 80, and the second right pressing member 82. The left hand arm 110, the first left gripping member 112, the second left gripping member 114, the first left claw 116, the second left claw 118, the first left pressing member 120, and the second left pressing member 122 are all symmetrical with respect to the virtual plane P1 (see Figure 3) with respect to the right hand arm 70, the first right gripping member 72, the second right gripping member 74, the first right claw 76, the second right claw 78, the first right pressing member 80, and the second right pressing member 82. The shape and material of the left hand arm 110 are the same as those of the right hand arm 70. The materials of the first left gripping member 112, the second left gripping member 114, the first left claw 116, the second left claw 118, the first left pressing member 120, and the second left pressing member 122 are the same as the materials of the first right gripping member 72, the second right gripping member 74, the first right claw 76, the second right claw 78, the first right pressing member 80, and the second right pressing member 82.

[0042] The left hand arm 110 is movable in the left-right direction relative to the arm support member 64. The left hand arm 110 is moved by the control of an arm drive device (not shown) by a control device 18 (see Figure 2). The configuration of the left hand arm 110 is substantially the same as that of the right hand arm 70. Therefore, as shown in Figure 5, the left hand arm 110 has a first opening 86, a second opening 88, and an internal space 90. The first opening 86 and the second opening 88 penetrate the rear wall 110a of the left hand arm 110.

[0043] As shown in Figure 6, the first left gripping member 112 and the second left gripping member 114 are attached to the right wall 110b of the left hand arm 110. The right wall 110b of the left hand arm 110 faces the left wall 70b of the right hand arm 70. The configuration of the first left gripping member 112 is substantially the same as that of the first right gripping member 72, and the configuration of the second left gripping member 114 is substantially the same as that of the second right gripping member 74.

[0044] The first left claw 116 protrudes to the right from the upper wall 110c of the left hand arm 110 toward the first right claw 76. The second left claw 118 protrudes to the right from the lower wall 110d of the left hand arm 110 toward the second right claw 78. The length of the first left claw 116 protruding from the right wall 110b is shorter than the length of the second left claw 118 protruding from the right wall 110b.

[0045] The first left pressing member 120 and the second left pressing member 122 are attached to the right wall 110b of the left hand arm 110. The configuration of the first left pressing member 120 is substantially the same as that of the second right pressing member 82. Therefore, the first left pressing member 120 includes a first contact portion 100 and a second contact portion 102. The first left pressing member 120 is rotatable around a pivot axis AX12 that extends in the left-right direction. The first left pressing member 120 rotates between a first position and a second position. The configuration of the second left pressing member 122 is substantially the same as that of the first right pressing member 80. Therefore, the second left pressing member 122 includes a first contact portion 94 and a second contact portion 96. The second left pressing member 122 is rotatable around a pivot axis AX13 that extends in the left-right direction. The second left pressing member 122 rotates between the first position and the second position.

[0046] As shown in Figure 5, the robot hand 44 further comprises drive units 130 and 132, and link units 134 and 136. The drive units 130 and 132 are simultaneously controlled by a control device 18 (see Figure 2). The drive unit 130 and link unit 134 are located in the internal space 90 of the right hand arm 70. Link unit 134 connects the first right pressing member 80 and the second right pressing member 82. Link unit 134 is operated by the drive unit 130. This causes link unit 134 to rotate the first right pressing member 80 and the second right pressing member 82 simultaneously. The drive unit 132 and link unit 136 are located in the internal space 90 of the left hand arm 110. Link unit 136 connects the first left pressing member 120 and the second left pressing member 122. Link unit 136 is operated by the drive unit 132. As a result, the link unit 136 rotates the first left pressing member 120 and the second left pressing member 122 simultaneously. The configuration of the drive unit 130 is substantially the same as that of the drive unit 132, and the configuration of the link unit 134 is substantially the same as that of the link unit 136. For this reason, the following explanation will use the drive unit 130 and the link unit 134 as examples.

[0047] The drive unit 130 is positioned closer to the first opening 86 and the second opening 88 than the link unit 134. The drive unit 130 consists, for example, of a cylinder and a piston rod that moves back and forth by the cylinder.

[0048] The link unit 134 comprises a first member 140, a second member 142, and a connecting member 144. The first member 140, the second member 142, and the connecting member 144 have an elongated plate shape.

[0049] One end of the first member 140 is rotatably attached to the drive end of the drive device 130. The central portion of the first member 140 is directly or indirectly attached to the second right pressing member 82, and the two are integrated. The first member 140 is rotatable around the pivot axis AX11, and when the first member 140 rotates, the second right pressing member 82 also rotates.

[0050] One end of the second member 142 is directly or indirectly attached to the first right pressing member 80, and the two are integrated. The second member 142 is rotatable around the pivot axis AX10, and when the second member 142 rotates, the first right pressing member 80 also rotates.

[0051] The connecting member 144 is rotatably attached to the other end of the first member 140 and the other end of the second member 142.

[0052] As shown in Figures 5 and 7, when the drive unit 130 is operated, one end of the first member 140 is operated by the drive unit 130. This causes the first member 140 to rotate around the pivot axis AX11. As the first member 140 rotates, one end of the connecting member 144 is operated, and consequently the other end of the connecting member 144 operates one end of the second member 142, causing the second member 142 to rotate around the pivot axis AX10. As a result, the first right pressing member 80 rotates from the first position to the second position, and at the same time the second right pressing member 82 rotates from the first position to the second position, or the first right pressing member 80 rotates from the second position to the first position, and at the same time the second right pressing member 82 rotates from the second position to the first position.

[0053] The robot hand 44 is further equipped with a cooling mechanism 150. The cooling mechanism 150 is provided on the right hand arm 70 and the left hand arm 110. The cooling mechanism 150 is equipped with a supply device 152.

[0054] The supply device 152 is configured to supply fluid (refrigerant) to the right hand arm 70 and the left hand arm 110 under the control of the control device 18 (see Figure 2). The fluid is, for example, a cooling gas or compressed air. In a modified example, the fluid may be a liquid such as water. The supply device 152 is attached to the first opening 86 and the second opening 88 of the right hand arm 70, and the first opening 86 and the second opening 88 of the left hand arm 110. The supply device 152 supplies the fluid to the internal space 90 through the first opening 86 of the right hand arm 70 and the first opening 86 of the left hand arm 110. The right hand arm 70 and the left hand arm 110 are cooled as the fluid flows through the internal space 90. In Figures 5 and 7, the direction of fluid flow is illustrated by arrow lines. After flowing through the internal space 90, the fluid is discharged to the outside of the internal space 90 through the second opening 88 of the right hand arm 70 and the second opening 88 of the left hand arm 110. Furthermore, a fluid channel is formed in the internal space 90, and the fluid channel may control the fluid flow in the internal space 90. This prevents the fluid from taking a shortcut from the first opening 86 to the second opening 88, and allows for efficient cooling of the entire hand arms 70 and 110. The fluid channel may be formed by a pipe placed within the internal space 90. In this configuration, the pipe has multiple nozzles, and the fluid may be ejected to the outside of the pipe through the multiple nozzles.

[0055] As shown in Figure 8, the robot hand 44 further includes a shutter 160 and a saggar detection sensor 162.

[0056] The shutter 160 is movably attached to the heat shield member 52. The shutter 160 moves between an open position and a closed position under the control of the control device 18 (see Figure 2). When the shutter 160 is in the open position, it opens the opening 166 of the heat shield member 52 and the opening 168 of the arm support member 64. As shown in Figure 9, when the shutter 160 is in the closed position, it closes the opening 166 of the heat shield member 52 and the opening 168 of the arm support member 64.

[0057] The saggar detection sensor 162 is located inside the arm support member 64. The saggar detection sensor 162 detects whether the saggar 2 is positioned in a predetermined location. The saggar detection sensor 162 is, for example, a laser sensor. As shown in Figure 8, when the shutter 160 is in the open position, the saggar detection sensor 162, under the control of the control device 18 (see Figure 2), projects a laser beam towards the opening 166 of the heat shield member 52 and the opening 168 of the arm support member 64. When the saggar detection sensor 162 receives the laser beam within a predetermined period after it has projected it, the saggar 2 is positioned in a predetermined location.

[0058] As shown in Figures 10 to 17, the robot 16, under the control of the control device 18 (see Figure 2), grasps the sagger 2 that has been removed from the heat treatment furnace 12 (see Figure 1), retrieves the material to be processed 4 from the sagger 2, and places the sagger 2 on the base plate 8. The robot 16 sequentially performs the following steps: preparation, first grasping, lifting, positioning, second grasping, first moving, first inversion, second inversion, second moving, positioning release, lowering, and grasping release.

[0059] As shown in Figure 10, in the preparation step, the robot arm 42 (see Figure 2) operates based on the position and orientation of the sagger 2 detected by the sagger detection device 36 (see Figure 2), and the robot hand 44 moves so that the sagger 2 is positioned between the right hand arm 70 and the left hand arm 110. Next, as shown in Figure 8, the shutter 160 moves from the closed position to the open position, and the sagger detection sensor 162 emits a laser. When the control device 18 (see Figure 2) detects that the sagger detection sensor 162 has received the laser within a predetermined period, the shutter 160 moves from the open position to the closed position. This suppresses the transfer of heat from the sagger 2 to the sagger detection sensor 162 compared to a configuration in which the shutter 160 is always in the closed position. After that, the first gripping step is performed.

[0060] As shown in Figures 11 and 12, in the first gripping step, the right hand arm 70 and the left hand arm 110 move closer to each other. As a result, the sagger 2 is sandwiched between the first right gripping member 72 and the first left gripping member 112, and between the second right gripping member 74 and the second left gripping member 114. The sagger 2 is gripped with a first gripping force by the first right gripping member 72, the second right gripping member 74, the first left gripping member 112, and the second left gripping member 114. At this time, the sagger 2 is in contact with the first right gripping member 72, the second right gripping member 74, the first left gripping member 112, and the second left gripping member 114, but not in contact with the right hand arm 70 and the left hand arm 110. By creating clearances between the sagger 2 and the right hand arm 70, and between the sagger 2 and the left hand arm 110, the transfer of heat from the sagger 2 to the right hand arm 70 and the left hand arm 110 can be suppressed compared to a configuration in which the sagger 2 is in contact with the right hand arm 70 and the left hand arm 110. Furthermore, as shown in Figure 5, since the fluid passes through the internal space 90 of the right hand arm 70 and the left hand arm 110, it is possible to suppress the right hand arm 70 and the left hand arm 110 from becoming overheated. This suppresses malfunctions of the hand arm sections 54 and 56, i.e., the robot hand 44. In addition, since the first opening 86 and the second opening 88 are located on the rear walls 70a and 110a, interference between the supply device 152 and the sagger 2 can be suppressed.

[0061] As shown in Figures 11 and 12, the movement of the right hand arm 70 and the left hand arm 110 causes the first right claw 76 and the first left claw 116 to be inserted into the notches 2a of the crag 2 being gripped. This positions the first right claw 76 and the first left claw 116 on the upper side of the crag 2 being gripped. In addition, the second right claw 78 and the second left claw 118 (see Figure 6) are inserted into the notches 2a of the crag 2 located on the lower side of the crag 2 being gripped. This positions the second right claw 78 and the second left claw 118 on the lower side of the crag 2 being gripped (i.e., on the side where the first right claw 76 and the first left claw 116 are not positioned). As a result, the crag 2 is positioned between the first right claw 76 and the second right claw 78, and between the first left claw 116 and the second left claw 118. Furthermore, if the sagger 2 to be gripped is placed on the spacer 6 (see Figure 2), the second right claw 78 and the second left claw 118 are inserted between the sagger 2 and the base plate 8 (see Figure 2). In the first gripping step, the steps of gripping the sagger 2 with the first right gripping member 72, the second right gripping member 74, the first left gripping member 112, and the second left gripping member 114, positioning the first right claw 76 and the first left claw 116 on the upper side of the sagger 2, and positioning the second right claw 78 and the second left claw 118 on the lower side of the sagger 2 are performed simultaneously.

[0062] After the right hand arm 70 and the left hand arm 110 move closer to each other, the shutter 160 moves from the closed position to the open position, as shown in Figure 8, and the saggar detection sensor 162 emits a laser beam. When the control device 18 (see Figure 2) detects that the saggar detection sensor 162 has received the laser beam within a predetermined period, the shutter 160 moves from the open position to the closed position. After that, the lifting process is performed.

[0063] As shown in Figure 13, during the lifting process, the robot arm 42 (see Figure 2) moves, causing the robot hand 44 to move upward. This lifts the crest 2 by the robot hand 44, separating it from the base plate 8. If the crest 2 being gripped is placed on a spacer 6, the crest 2 will separate from the spacer 6. When the crest 2 is lifted by the robot arm 42, it rests on the second right claw 78 and the second left claw 118. In this state, clearances are formed between the crest 2 and the first right claw 76, and between the crest 2 and the second left claw 118.

[0064] As shown in Figure 7, in the positioning process after the lifting process, the drive units 130 and 132 operate simultaneously, causing the link unit 134 to operate the first right pressing member 80 and the second right pressing member 82 simultaneously, while the link unit 136 operates the first left pressing member 120 and the second left pressing member 122 simultaneously. As shown in Figure 14, the first right pressing member 80, the second right pressing member 82, the first left pressing member 120 (see Figure 6), and the second left pressing member 122 (see Figure 6) rotate simultaneously from the second position to the first position. As a result, the second contact portion 96 of the first right pressing member 80, the second contact portion 102 of the second right pressing member 82, the second contact portion 102 of the first left pressing member 120, and the second contact portion 96 of the second left pressing member 122 come into contact with the lower surface of the sagger 2 in the vertical direction, pressing the sagger 2 against the first right claw 76 and the first left claw 116 (see Figure 6). Consequently, the sagger 2 moves upward relative to the first right gripping member 72, the second right gripping member 74, the first left gripping member 112, and the second left gripping member 114, and moves away from the second right claw 78 and the second left claw 118 (see Figure 6). Clearances are formed between the sagger 2 and the second right claw 78, and between the sagger 2 and the second left claw 118. Furthermore, the rotation of the first right pressing member 80, the second right pressing member 82, the first left pressing member 120, and the second left pressing member 122 causes the sagger 2 to come into contact with the first contact portion 94 of the first right pressing member 80, the first contact portion 100 of the second right pressing member 82, the first contact portion 100 of the first left pressing member 120, and the first contact portion 94 of the second left pressing member 122 in the front-rear direction. As a result, the sagger 2 is sandwiched between the first contact portion 94 of the first right pressing member 80 and the first contact portion 100 of the second right pressing member 82, and between the first contact portion 100 of the first left pressing member 120 and the first contact portion 94 of the second left pressing member 122. Thus, the sagger 2 is positioned in the front-rear and up-down directions relative to the robot hand 44. Furthermore, in the positioning process, the steps of positioning the crest 2 in the front-to-back direction relative to the robot hand 44 and positioning the crest 2 in the up-to-down direction relative to the robot hand 44 are performed simultaneously. By performing the positioning process, it is possible to prevent the crest 2 from falling from the robot hand 44.Furthermore, compared to a configuration in which the steps of positioning the crest 2 in the front-to-back direction relative to the robot hand 44 and positioning the crest 2 in the up-to-down direction relative to the robot hand 44 are performed separately, the time required for positioning can be shortened. In addition, rattling of the crest 2 in the front-to-back and up-to-down directions can be suppressed. Moreover, movement of the crest 2 in the up-to-down and front-to-back directions can be suppressed when the robot hand 44 is operating. As a result, misalignment of the crest 2 in the up-to-down and front-to-back directions relative to the robot hand 44 can be suppressed.

[0065] As shown in Figure 11, in the second gripping step after the positioning step, the right hand arm 70 and the left hand arm 110 move slightly closer to each other. As a result, the sagger 2 is gripped with a second gripping force that is greater than the first gripping force applied in the first gripping step. This allows the sagger 2 to be gripped with a second gripping force in the left-right direction relative to the robot hand 44, suppressing rattling of the sagger 2 in the left-right direction. Furthermore, movement of the sagger 2 in the front-back and up-down directions is further suppressed when the robot hand 44 is operating. This further suppresses misalignment of the sagger 2 in the front-back and up-down directions relative to the robot hand 44. In this embodiment, the contact members that come into contact with the sagger 2 (for example, gripping members 72, 74, right claws 76, 78 and pressing members 80, 82) are made of ceramics. This allows the robot hand 44 to grip the high-temperature sagger 2 after it has been removed from the heat treatment furnace 12. Furthermore, in configurations where the contact member is made by coating a metal member with ceramics, the ceramics may peel off from the metal material. However, in the contact member of this embodiment, peeling does not occur. This makes it possible to suppress a decrease in the heat resistance and corrosion resistance of the contact member.

[0066] As shown in Figure 15, in the first moving step after the second gripping step, the robot arm 42 (see Figure 2) operates and the robot hand 44 moves, causing the saggar 2 to move to the collection container 34. Next, as shown in Figure 8, the shutter 160 moves from the closed position to the open position, and the saggar detection sensor 162 emits a laser beam. When the control device 18 (see Figure 2) detects that the saggar detection sensor 162 has received the laser beam within a predetermined period, the shutter 160 moves from the open position to the closed position. After that, the first inversion step is performed.

[0067] As shown in Figure 15, in the first inversion step, the robot arm 42 (see Figure 2) moves the robot hand 44 180 degrees around axis AX6 (see Figure 2), causing the sagger 2 to invert above the collection container 34. As the opening of the sagger 2 faces downward, the material to be processed 4 inside the sagger 2 is collected into the collection container 34. Furthermore, since the length of the first right claw 76 protruding from the left wall 70b is shorter in the left-right direction than the length of the second right claw 78 protruding from the left wall 70b, and the length of the first left claw 116 protruding from the right wall 110b is shorter in the left-right direction than the length of the second left claw 118 protruding from the right wall 110b, it is possible to prevent the material to be processed 4 from resting on the first right claw 76 and the first left claw 116.

[0068] In the second inversion step following the first inversion step, the robot arm 42 (see Figure 2) moves the robot hand 44 180 degrees around axis AX6 (see Figure 2), causing the saggar 2 to invert above the collection container 34. As a result, the opening of the saggar 2 faces upward. The direction in which the robot hand 44 rotates in the second inversion step is opposite to the direction in which the robot hand 44 rotates in the first inversion step. Next, as shown in Figure 8, the shutter 160 moves from the closed position to the open position, and the saggar detection sensor 162 emits a laser beam. When the control device 18 (see Figure 2) detects that the saggar detection sensor 162 has received the laser beam within a predetermined period, the shutter 160 moves from the open position to the closed position. After that, the second movement step is executed.

[0069] As shown in Figure 16, in the second moving step, the robot arm 42 (see Figure 2) operates and the robot hand 44 moves, causing the sagger 2 to move to the base plate 8. Alternatively, the robot hand 44 may move the sagger 2 to a location other than the base plate 8, for example, to a lift located at one end of a conveyor belt that transports the sagger 2 to the entrance 20.

[0070] In the positioning release step after the second movement step, the right hand arm 70 and the left hand arm 110 move slightly apart from each other. As a result, the sagger 2 is gripped by the first right gripping member 72, the second right gripping member 74, the first left gripping member 112, and the second left gripping member 114 with the first gripping force. This releases the left-right positioning of the sagger 2 relative to the robot hand 44. Next, as shown in Figure 5, the drive units 130 and 132 operate simultaneously, causing the link unit 134 to simultaneously operate the first right pressing member 80 and the second right pressing member 82, and the link unit 136 to simultaneously operate the first left pressing member 120 and the second left pressing member 122. As shown in Figure 16, the first right pressing member 80, the second right pressing member 82, the first left pressing member 120 (see Figure 6), and the second left pressing member 122 (see Figure 6) rotate simultaneously from the first position to the second position. This releases the force pressing the sagger 2 toward the first right claw 76 and the first left claw 116 by the first right pressing member 80, the second right pressing member 82, the first left pressing member 120, and the second left pressing member 122. The sagger 2 is held by the gripping members 72, 74, 112, and 114 with a first gripping force. If the first gripping force is set to a force smaller than the weight of the sagger 2, the sagger 2 will move downward due to its own weight. As a result, the crest 2 separates from the first right claw 76 and the first left claw 116 and is placed on the second right claw 78 and the second left claw 118 (see Figure 6). Thus, the positioning of the crest 2 in the front-to-back and up-to-down directions relative to the robot hand 44 is released. However, if the first gripping force is set to a force greater than the weight of the crest 2, the crest 2 will be held in a position where it is in contact with the first right claw 76 and the first left claw 116 without separating from them.

[0071] As shown in Figure 17, in the lowering process after the positioning release process, the robot arm 42 (see Figure 2) operates and the robot hand 44 moves downward. As a result, the sagger 2 is lowered and placed on the spacer 6 on the base plate 8.

[0072] In the gripping release step after the lowering step, the right hand arm 70 and the left hand arm 110 move further apart from each other. As a result, the sagger 2 separates from the first right gripping member 72, the second right gripping member 74, the first left gripping member 112, and the second left gripping member 114. Consequently, the grip of the sagger 2 by the first right gripping member 72, the second right gripping member 74, the first left gripping member 112, and the second left gripping member 114 is released. In addition, the first right claw 76 and the first left claw 116 (see Figure 6) disengage from the notch 2a of the sagger 2, and the second right claw 78 and the second left claw 118 (see Figure 6) disengage from between the sagger 2 and the base plate 8.

[0073] (effect) In the above embodiment, the supply device 152 supplies fluid to the internal space 90 of the right hand arm 54 and the left hand arm 56. The right hand arm 54 and the left hand arm 56 are cooled as the fluid flows through the internal space 90. As a result, even if the right hand arm 54 and the left hand arm 56 grasp the high-temperature saggar 2, it is possible to suppress the right hand arm 54 and the left hand arm 56 from becoming overheated. As a result, malfunctions of the robot hand 44 can be suppressed.

[0074] (Correspondence) The right hand arm section 54 and the left hand arm section 56 are examples of "hand arm sections". The first right gripping member 72, the second right gripping member 74, the first left gripping member 112, and the second left gripping member 114 are examples of "contact members". The rear walls 70a and 110a are "the 2 This is an example of a "wall". The left wall 70b and the right wall 110b are "the 1 This is an example of a "wall".

[0075] (Second example) The differences from the first embodiment will be explained in the second embodiment. As shown in Figure 18, in the second embodiment, the right hand arm portion 54 is equipped with a first right pressing member 280, a second right pressing member 282, a third right pressing member 284, and a fourth right pressing member 286, in place of the first right pressing member 80 and the second right pressing member 82 of the first embodiment.

[0076] The first right pressing member 280, the second right pressing member 282, the third right pressing member 284, and the fourth right pressing member 286 are attached to the left wall 70b of the right hand arm 70. The first right pressing member 280 and the second right pressing member 282 are positioned in front of the first right gripping member 72 (see Figure 4), the second right gripping member 74 (see Figure 4), the first right claw 76, and the second right claw 78. The third right pressing member 284 and the fourth right pressing member 286 are positioned behind the first right gripping member 72, the second right gripping member 74, the first right claw 76, and the second right claw 78. In the front-rear direction, the third right pressing member 284 and the fourth right pressing member 286 are positioned between the first right pressing member 280 and the second right pressing member 282. The first right pressing member 280 and the fourth right pressing member 286 are movable in the front-rear direction. The second right pressing member 282 and the third right pressing member 284 are movable in the up-down direction.

[0077] As shown in Figure 19, the left hand arm portion 56 replaces the first left pressing member 120 and the second left pressing member 122 of the first embodiment with a first left pressing member 290, a second left pressing member 292, a third left pressing member 294, and a fourth left pressing member 296. Each of the first left pressing member 290, the second left pressing member 292, the third left pressing member 294, and the fourth left pressing member 296 is symmetrical with respect to the virtual plane P1 with respect to each of the first right pressing member 280, the second right pressing member 282, the third right pressing member 284, and the fourth right pressing member 286. The first left pressing member 290, the second left pressing member 292, the third left pressing member 294, and the fourth left pressing member 296 are attached to the right wall 110b of the left hand arm 110. The first left pressing member 290 and the fourth left pressing member 296 are movable in the front-rear direction. The second left pressing member 292 and the third left pressing member 294 are movable in the up-down direction.

[0078] As shown in Figure 20, in the positioning step of the second embodiment, first, the first right pressing member 280 and the fourth right pressing member 286 move closer to each other, and at the same time, the first left pressing member 290 (see Figure 19) and the fourth left pressing member 296 (see Figure 19) move closer to each other. As a result, the sagger 2 is sandwiched between the first right pressing member 280 and the fourth right pressing member 286, and between the first left pressing member 290 and the fourth left pressing member 296. Thus, the sagger 2 is positioned in the front-rear direction with respect to the robot hand 44. Next, as shown in Figure 21, the second right pressing member 282, the third right pressing member 284, the second left pressing member 292 (see Figure 19), and the third left pressing member 294 (see Figure 19) move upward simultaneously. As a result, the second right pressing member 282, the third right pressing member 284, the second left pressing member 292, and the third left pressing member 294 press the sagger 2 against the first right claw 76 and the first left claw 116 (see Figure 19). Thus, the sagger 2 is positioned vertically relative to the robot hand 44.

[0079] As shown in Figure 18, in the positioning release step of the second embodiment, the second right pressing member 282, the third right pressing member 284, the second left pressing member 292, and the third left pressing member 294 move downward simultaneously. As a result, the crest 2 is placed on the second right claw 78 and the second left claw 118 (see Figure 6). At the same time, the first right pressing member 280 and the fourth right pressing member 286 move away from each other, and the first left pressing member 290 and the fourth left pressing member 296 move away from each other. As a result, the crest 2 is separated from the first right pressing member 280, the fourth right pressing member 286, the first left pressing member 290, and the fourth left pressing member 296. Thus, the positioning of the crest 2 in the front-to-back and up-to-down directions relative to the robot hand 44 is released.

[0080] (modified version) In one embodiment, the conveying device 14 may have multiple rollers instead of the guide member 28 and pusher 30. In this configuration, both ends of the multiple rollers are rotatably supported by the heat treatment furnace 12. As the multiple rollers rotate, the base plate 8 is conveyed on the multiple rollers. Alternatively, multiple saggers 2 may be placed on the base plate 8 in a stacked vertical position, or only one sagger 2 may be placed on the base plate 8. Furthermore, the saggers 2 may be placed directly on the rollers without using the base plate 8. In this configuration, the heat treatment system 10 may include a lifting device to separate the saggers 2 from the rollers. The robot hand 44 grasps the saggers 2 after they have been separated from the rollers by the lifting device (i.e., after a gap has been formed between the saggers 2 and the rollers).

[0081] In one embodiment, the right hand arm portion 54 may be equipped with only one of the first right gripping member 72 and the second right gripping member 74, or it may be equipped with one or more gripping members in addition to the first right gripping member 72 and the second right gripping member 74. Similarly, the left hand arm portion 56 may be equipped with only one of the first left gripping member 112 and the second left gripping member 114, or it may be equipped with one or more gripping members in addition to the first left gripping member 112 and the second left gripping member 114.

[0082] In one embodiment, during the positioning process, the first right pressing member 80, the second right pressing member 82, the first left pressing member 120, and the second left pressing member 122 may press the sagger 2 against the second right claw 78 and the second left claw 118. In this configuration, the sagger 2 is pressed downwards.

[0083] In one embodiment, the positioning step does not necessarily require the step of positioning the sagger 2 in the front-rear direction relative to the robot hand 44.

[0084] In one embodiment, the first opening 86 and the second opening 88 may be located on a wall other than the rear wall 70a of the right hand arm 70 (or a wall other than the rear wall 110a of the left hand arm 110). Furthermore, the first opening 86 and the second opening 88 may be spaced apart in the left-right or front-back direction. Additionally, the wall of the right hand arm 70 (or the wall of the left hand arm 110) on which the first opening 86 is located may be different from the wall of the right hand arm 70 (or the wall of the left hand arm 110) on which the second opening 88 is located. For example, the first opening 86 may be located on the rear wall 70a of the right hand arm 70 (or the rear wall 110a of the left hand arm 110), and the second opening 88 may be located on the front wall of the right hand arm 70 (or the front wall of the left hand arm 110). This can suppress fluid shortcuts from the first opening 86 to the second opening 88.

[0085] The specific examples of the technology disclosed herein have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples described above. Furthermore, the technical elements described herein or in the drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated herein or in the drawings achieves multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of Symbols]

[0086] 2: Sagger 4: Items to be processed 10: Heat treatment system 12: Heat treatment furnace 16: Robot 34: Collection container 42: Robot Arm 44: Robot Hand 48: Base section 50: Mounting parts 52: Heat-shielding material 54: Right hand arm section 56: Left hand arm section 70: Right Hand Arm 70a: Back wall 70b:Left wall 72: 1st right gripping member 74:Second right gripping member 76: First right claw 78: Second right claw 80: First right pressing member 82: Second right pressing member 86: First opening 88: Second opening 90: Interior space 94: 1st contact part 96:Second contact part 100: 1st contact part 102:Second contact part 110: Left hand arm 110a: Back wall 110b: Right wall 112: First left gripping member 114: Second left gripping member 116: 1st left claw 118: 2nd left claw 120: First left pressing member 122: Second left pressing member 134, 136: Link Unit 150: Cooling mechanism 152: Feeding device 280: First right pressing member 282: Second right pressing member 284: Third right pressing member 286: Fourth right pressing member 290: First left pressing member 292: Second left pressing member 294: Third left pressing member 296: Fourth left pressing member AX10, AX11, AX12, AX13: Rotary shaft

Claims

1. A robotic hand for grasping a saggar removed from a heat treatment furnace, A pair of hand arms for gripping the aforementioned saggar, The hand arm portion is provided with a cooling mechanism for cooling the hand arm portion, The aforementioned hand arm portion comprises a hand arm having a first opening, a second opening, and an internal space. The cooling mechanism is attached to the first opening and includes a supply device that supplies fluid to the internal space through the first opening and discharges the fluid from the second opening, in a robot hand.

2. The hand arm portion further includes a contact member that contacts the sag when gripping the sag, The aforementioned hand arm is The first wall to which the contact member is attached, The robot hand according to claim 1, comprising a second wall different from the first wall, wherein the first opening is located thereon.

3. The supply device is attached to the second opening, The robot hand according to claim 2, wherein the second opening is located in the second wall.

4. The robot hand according to claim 1, wherein the fluid is a cooling gas or compressed air.

5. A base portion that supports the aforementioned hand arm portion, The system further includes a mounting member that allows the base portion to be attached to a robot arm, The robot hand according to any one of claims 1 to 4, wherein the thermal conductivity of the mounting member is smaller than the thermal conductivity of the base portion.

6. The robot hand according to claim 5, further comprising a heat-shielding member disposed between the sagger and the base when the sagger is held by the hand arm.

7. The robot hand according to claim 6, wherein the heat shielding member is attached to the base portion.

8. A robotic arm and The system includes a robotic hand attached to the aforementioned robotic arm, which grasps the saggar removed from the heat treatment furnace, The aforementioned robot hand is A pair of hand arms for gripping the aforementioned saggar, The hand arm portion is provided with a cooling mechanism for cooling the hand arm portion, The aforementioned hand arm portion comprises a hand arm having a first opening, a second opening, and an internal space. The cooling mechanism is attached to the first opening and includes a supply device that supplies fluid to the internal space through the first opening and discharges the fluid from the second opening. robot.

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