Tool adapter and automatic tool swapping device

Abstract

Provided is a tool adapter capable of contributing to the reduction of a moment which is from a robot tool and which acts around a joint of a robot arm. A tool adapter 27 of an automatic tool swapping device 25 is coupled to a robot tool and detachably coupled to a robot adapter 26 which is coupled to a robot arm. The tool adapter 27 comprises: an upper housing 61 that is formed from a solid material having a first strength, and that has a connection surface 28 connected to the robot adapter 26; a lower housing 62 that is formed from a solid material having a second strength smaller than the first strength, and that is coupled to the upper housing 61 and connects a robot tool connection-article to the robot tool; and a lock part 54 that is received by the upper housing 61 from below, and that transmits a pressing force, which presses the connection surface 28 to the robot adapter 26, from a cam member 35 of the robot adapter 26 to the upper housing 61.

Description

Tool adapter and automatic tool changer

[0001] The present invention relates to a tool adapter that is coupled to a robot tool and is removably coupled to a robot adapter that is coupled to a robot arm.

[0002] When attaching a robot tool, a robot adapter is connected to the robot arm, while a tool adapter is connected to the robot tool. By connecting the tool adapter to the robot adapter, the robot tool is fixed to the robot arm. At this time, when a pressing force acts on the locking part of the tool adapter from the cam of the robot adapter, the robot adapter can be held on the connecting surface without rattle. The locking part is fixed to the tool adapter with a bolt. The pressing force acting on the locking part is supported by the base material of the tool adapter. The base material of the tool adapter is processed from aluminum, for example. Aluminum contributes to reducing the weight of the tool adapter.

[0003] Patent No. 5697549

[0004] A large pressure force acts on the base material of the tool adapter to maintain the connection. The base material needs to have the strength to support the pressure force, so it has a corresponding thickness. The lock part and tool adapter are fixed with bolts, so the thickness of the base material of the tool adapter increases. The robot tool moves away from the joint depending on the thickness of the base material. In a robot arm, the moment acting from the robot tool around the joint increases.

[0005] An object of the present invention is to provide a tool adapter that can contribute to reducing the moment acting from a robot tool around the joint of a robot arm.

[0006] A tool adapter according to one aspect of the present invention is coupled to a robot tool and detachably coupled to a robot adapter coupled to a robot arm. The tool adapter includes: an upper housing formed from a solid material having a first strength and having an upward coupling surface coupled to the robot adapter from below; a lower housing formed from a solid material having a second strength smaller than the first strength and coupled to the upper housing from below to connect a connector of the robot tool to the robot tool coupled from below; and a lock part received by the upper housing from below and transmitting a pressing force, which presses the coupling surface against the robot adapter, from a cam of the robot adapter to the upper housing.

[0007] As described above, according to one aspect of the present invention, a tool adapter can be provided that can contribute to reducing the moment acting from a robot tool around a joint of a robot arm.

[0008] 1 is a side view schematically illustrating the configuration of a robot according to an embodiment of the present invention. It is an enlarged cross-sectional view of the automatic tool changer taken along line 2-2 in FIG. 1, illustrating a state in which a cam surface is engaged with a lock part. It corresponds to FIG. 2 and illustrates a state in which the cam surface has disengaged from the lock part. It corresponds to FIG. 3 and illustrates a state in which the robot adapter is detached from the tool adapter. It is an enlarged perspective view schematically illustrating the exterior of the tool adapter. It corresponds to the enlarged cross-sectional view taken along line 6-6 in FIG. 5 and illustrates an enlarged front view showing the relationship between the lock part and the upper and lower housings. It corresponds to the enlarged cross-sectional view taken along line 7-7 in FIG. 5 and illustrates the relationship between the lock part and a set screw. It is an enlarged perspective view showing the lock part observed from the lower housing side. It corresponds to the cross-section taken along line 9-9 in FIG. 8 and illustrates an enlarged perspective view showing a groove engraved in the lock part.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] 1 shows a schematic configuration of a robot 11 according to an embodiment of the present invention. The robot 11 includes a base 13 fixed to a fixed surface 12, such as a floor, and a robot arm 15 rotatably connected to the base 13 around a first joint 14. The first joint 14 allows the robot arm 15 to rotate around a horizontal axis. The rotation of the robot arm 15 is achieved by the driving force of a built-in electric motor. A robot tool 16 is attached to the tip of the robot arm 15.

[0011] The robot arm 15 includes a first link 19, a second link 21, and a third link 22, which are connected in sequence by a second joint 17 and a third joint 18. The first link 19 and the second link 21 are formed of two members that rotate relatively around axes 23 and 24 at an intermediate position. When the two members rotate relative to each other at the first link 19, the orientation of the second link 21 can be changed around the axis 23. When the two members rotate relative to each other at the second link 21, the orientation of the third link 22 can be changed around the axis 24. The axes 23 and 24 define the longitudinal directions of the links 19 and 21.

[0012] The second joint 17 allows the second link 21 to rotate relative to the first link 19 around a horizontal axis perpendicular to the axis 23 of the first link 19. The rotational movement of the second link 21 is realized by the driving force of a built-in electric motor. The third joint 18 allows the third link 22 to rotate relative to the second link 21 around a rotation axis perpendicular to the axis 24 of the second link 21. The rotational movement of the third link 22 is realized by the driving force of a built-in electric motor.

[0013] The automatic tool changer 25 is disposed between the tip of the third link 22 and the robot tool 16. The automatic tool changer 25 includes a robot adapter 26 connected to the robot arm 15 and a tool adapter 27 connected to the robot tool 16. The tool adapter 27 is detachably connected to the robot adapter 26. The robot tool 16 is fixed to the robot arm 15 by connecting the tool adapter 27 to the robot adapter 26.

[0014] When mounting, the robot tool 16 is held in an upright position. In the upright position, the coupling surface 28 of the tool adapter 27 fixed to the robot tool 16 is aligned horizontally and facing upward. The coupling surface 28 of the tool adapter 27 is formed in a plane perpendicular to the axis 29 of the third link 22. The coupling surface 31 of the robot adapter 26 is superimposed on the coupling surface 28 of the tool adapter 27. The coupling surface 31 of the robot adapter 26 is aligned horizontally and facing downward. The coupling surface 31 of the robot adapter 26 is also formed in a plane perpendicular to the axis 29 of the third link 22 and is joined to the coupling surface 28 of the tool adapter 27.

[0015] 2 , the tool adapter 27 has a through hole 34 drilled in the coupling surface 28 to receive the mating body 33 of the robot adapter 26. The mating body 33 protrudes downward from the coupling surface 31. When the coupling surface 31 of the robot adapter 26 is placed on the coupling surface 28 of the tool adapter 27, the mating body 33 enters the through hole 34.

[0016] A cam member 35 that protrudes outward from the outer periphery of the fitting body 33 is supported on the fitting body 33. To support the cam member 35, a support shaft 36 that is rotatably held by the fitting body 33 is formed. The support shaft 36 allows the cam member 35 to rotate about an axis 37. A plurality of cam members 35 are arranged at equal intervals around a center line 38 of the fitting body 33. In this example, three cam members 35 are arranged at 120° intervals around the center line 38. The center line 38 of the fitting body 33 is perpendicular to the connecting surface 31. In each cam member 35, the axis 37 is tangent to a circle drawn around the center line 38 in a plane perpendicular to the center line 38. The axes 37 and the center line 38 are set equidistant from each other.

[0017] A drive mechanism 41 is incorporated into the robot adapter 26, causing the cam member 35 to rotate about the axis 37. The drive mechanism 41 includes a cylinder 42 that defines an airtight cylindrical space coaxially with the center line 38, a piston 43 housed in the cylinder 42 so as to be displaceable in the axial direction of the center line 38, and a rod 44 that is coaxially connected to the piston 43 and protrudes downward from the coupling surface 31. A disc 45 is coaxially formed at the lower end of the rod 44. The disc 45 contacts the operating piece 35a of the cam member 35 from below. A ring 46 is formed on the rod 44 at a position spaced from the disc 45 in the axial direction of the center line 38 and extends around the rod 44. The ring 46 contacts the operating piece 35a of the cam member 35 from above. The cylindrical space within the cylinder 42 is divided into a first pressure chamber 47 and a second pressure chamber 48 according to the arrangement of the piston 43. When pressure increases in the first pressure chamber 47, the piston 43 is driven upward within the cylinder 42. The rod 44 and the disk 45 rise to their maximum. The disk 45 pushes up the operating piece 35a of the cam member 35. The cam surface 35b of the cam member 35 faces upward and protrudes outward from the fitting body 33. As shown in FIG. 3, when pressure increases in the second pressure chamber 48, the piston 43 is driven to its lowest position within the cylinder 42. The rod 44 and the ring 46 descend to their maximum. The ring 46 pushes down the operating piece 35a of the cam member 35. The cam surface 35b of the cam member 35 faces upward and is housed within the fitting body 33.

[0018] A first air passage 51 and a second air passage 52 are connected to the cylinder 42. The first air passage 51 is connected to the first pressure chamber 47. Air is introduced at high pressure from the first air passage 51 into the first pressure chamber 47. At this time, the pressure in the second pressure chamber 48 is released. The second air passage 52 is connected to the second pressure chamber 48. Air is introduced at high pressure from the second air passage 52 into the second pressure chamber 48. At this time, the pressure in the first pressure chamber 47 is released.

[0019] The first pressure chamber 47 contains a helical spring 53 wound around the rod 44. The helical spring 53 drives the piston 43 upward within the cylinder 42. The rod 44 and the disk 45 rise to their maximum position. The helical spring 53 maintains the positions of the rod 44 and the disk 45. Even if pressure is simultaneously released from the first pressure chamber 47 and the second pressure chamber 48, the cam surface 35b of the cam member 35 remains facing upward and outward from the mating body 33. Even if a problem occurs with the air pressure introduced into the first pressure chamber 47 and the second pressure chamber 48, the coupling between the robot arm 15 and the robot tool 16 can be maintained properly.

[0020] The tool adapter 27 includes a locking part 54 disposed in the through hole 34 and supporting the pressing force applied by the cam surface 35b of the cam member 35. A plurality of locking parts 54 are disposed at equal intervals around the center line 38 of the mating body 33 corresponding to each cam member 35. In this example, three locking parts 54 are disposed at 120° intervals around the center line 38. When pressure increases in the first pressure chamber 47, the cam surface 35b of the cam member 35 is pressed against the locking part 54 as the rod 44 and the disc body 45 rise. The cam member 35 converts the outward force around the axis 37 to generate a pressing force that presses the coupling surface 28 of the tool adapter 27 against the robot adapter 26. When the pressing force acts from the cam member 35 of the robot adapter 26 to the locking part 54 of the tool adapter 27, the robot adapter 26 can be held on the coupling surface 28 without rattle.

[0021] A positioning pin 55 is fixed to the robot adapter 26. The positioning pin 55 stands perpendicular to the coupling surface 31. When the coupling surface 31 of the robot adapter 26 is placed on the coupling surface 28 of the tool adapter 27, the positioning pin 55 is received in a positioning hole 56 drilled in the coupling surface 28 of the tool adapter 27. When the positioning pin 55 is fitted into the positioning hole 56, relative displacement between the coupling surface 28 and the coupling surface 31 in the in-plane direction is prevented. In this way, the corresponding cam surface 35b is aligned with each lock part 54, allowing a uniform pressing force to be applied to each lock part 54 from the cam surface 35b. Here, multiple sets of positioning pins 55 and positioning holes 56 are arranged around the center line 38.

[0022] As shown in FIG. 4 , the robot adapter 26 and the tool adapter 27 can be displaced relative to each other in the axial direction of the center line 38. At this time, high-pressure air is introduced into the second pressure chamber 48. The cam surface 35b of the cam member 35 faces upward and is housed in the fitting body 33. The engagement between the cam member 35 and the lock part 54 is released. In response to this relative displacement, the robot adapter 26 can be separated from the tool adapter 27. The robot tool 16 can be removed from the robot arm 15.

[0023] A connector 57 of the robot tool 16 is coupled to the tool adapter 27. The robot adapter 26 connects the connector 57 to the robot tool 16. For example, when a pipe is coupled to the tool adapter 27 as the connector 57, a flow path 58 of the pipe can be connected to a port 59 formed in the tool adapter 27. The port 59 can be connected to a pressure chamber of the robot tool 16.

[0024] As shown in FIG. 5 , the tool adapter 27 includes an upper housing 61 having an upward coupling surface 28 that is coupled to the robot adapter 26 from below when the robot tool 16 is in an upright position, and a lower housing 62 that is joined to the upper housing 61 from below. The upper housing 61 is made of a solid material having a first strength. Examples of the solid material having the first strength include stainless steel (e.g., SUS304) and carbon steel (e.g., S45C). The lower housing 62 is made of a solid material having a second strength that is weaker than the first strength. Examples of the solid material having the second strength include aluminum and hard resin.

[0025] As shown in FIG. 6 , the locking part 54 is received in the upper housing 61 from below. The locking part 54 is supported from below by a pair of supports 63 formed in the lower housing 62 at a distance sufficient to allow the cam member 35 to pass through. As shown in FIG. 7 , each support 63 has a threaded hole 65 formed therein, which penetrates the support 63 and receives a set screw 64 from below. The tip of the set screw 64 abuts against the locking part 54. The set screw 64 presses the locking part 54 against the upper housing 61. In this way, a restraining force is applied to the locking part 54. The axis of the set screw 64 is set parallel to the center line 38. Here, a hexagon socket head screw is used for the set screw 64. With a hexagon socket head screw, the screw head can be omitted. As a result, the formation of a protruding or countersunk portion at the screw head can be avoided.

[0026] 8, the lower housing 62 is formed with a step 67 that defines a space 66 that is open from the surface of the support body 63 in the axial direction of the setscrew 64. A tool can be inserted in the axial direction of the setscrew 64. By operating the tool, the setscrew 64 can be tightened toward the lock part 54. Similarly, by operating the tool, the setscrew 64 can be loosened.

[0027] 9 , a groove 68 is formed in the locking part 54 to receive the tip of the set screw 64 and prevent the locking part 54 from falling out from between the upper housing 61 and the lower housing 62. The groove 68 can reliably prevent the locking part 54 from falling out from between the upper housing 61 and the lower housing 62.

[0028] When attaching the robot tool 16, the robot adapter 26 is coupled to the robot arm 15, while the tool adapter 27 is coupled to the robot tool 16. The robot tool 16 is held in an upright position. High-pressure air is introduced into the second pressure chamber 48 of the robot adapter 26 from the second air passage 52. The rod 44 and the ring body 46 are lowered to their maximum extent against the elastic force of the helical spring 53. The ring body 46 presses down the operating piece 35a of the cam member 35. The cam surface 35b of the cam member 35 is housed within the fitting body 33.

[0029] The coupling surface 31 of the robot adapter 26 and the coupling surface 28 of the tool adapter 27 overlap in one horizontal plane. The fitting body 33 of the robot adapter 26 enters the through-hole 34 of the tool adapter 27. Because the cam member 35 is housed in the fitting body 33, interference between the cam member 35 and the tool adapter 27 can be avoided during the entry. The positioning pin 55 of the robot adapter 26 is fitted into the positioning hole 56 of the tool adapter 27. The cam surface 35b is precisely aligned with each lock part 54.

[0030] High-pressure air is introduced into the first pressure chamber 47 of the robot adapter 26 from the first air passage 51. When the connecting surfaces 31, 28 overlap, the rod 44 and the disk 45 rise to their maximum. The disk 45 pushes up the operating piece 35a of the cam member 35. The cam surface 35b is pressed against the lock part 54. A pressing force acts on the robot adapter 26 toward the connecting surface 28 of the tool adapter 27. The robot adapter 26 can be held on the connecting surface 28 without rattle. In this way, by connecting the tool adapter 27 to the robot adapter 26, the robot tool 16 is fixed to the robot arm 15.

[0031] When a pressing force is applied from the cam member 35 of the robot adapter 26 to the lock part 54 of the tool adapter 27, the tool adapter 27 requires high strength in the area where a large pressing force is applied to maintain the connection, but does not require as much strength in the area where the connecting part 57 is connected to the robot tool 16. When the upper housing 61 with a first strength and the lower housing 62 with a second strength are combined, the moment acting from the robot tool 16 around the joint 18 in the robot arm 15 can be reduced. As a practical option, a high-strength material has a high specific gravity. If the entire structure is molded from a solid material with the first strength, the overall weight increases, increasing the moment. If the entire structure is molded from a solid material with the second strength, the thickness increases, moving the robot tool away from the joint.

[0032] When replacing the robot tool 16, the robot tool 16 is placed on the stand. The robot arm 15 positions the robot tool 16 at a predetermined position. The robot tool 16 is held in an upright position. High-pressure air is introduced into the second pressure chamber 48 of the robot adapter 26 from the second air path 52. The rod 44 and the ring body 46 are lowered to their maximum extent against the elastic force of the helical spring 53. The ring body 46 presses down the operating piece 35a of the cam member 35. The cam surface 35b of the cam member 35 moves away from the lock part 54. The cam member 35 is housed within the fitting body 33. When the robot adapter 26 is pulled up vertically, it is separated from the tool adapter 27. The robot tool 16 is removed from the robot arm 15.

[0033] When replacing the lock part 54, the tool adapter 27 is removed from the robot tool 16. An operator can engage a tool with the set screw 64 from the space 66. When the set screw 64 is loosened by operating the tool, the lock part 54 can be removed from the space between the upper housing 61 and the lower housing 62. The lock part 54 is removed from the through hole 34. A new lock part 54 can be inserted from the through hole 34 into the space between the upper housing 61 and the lower housing 62. When the set screw 64 is tightened toward the lock part 54 by operating the tool, the tip of the set screw 64 hits the lock part 54 from below. The set screw 64 can apply a restraining force to the lock part 54.

[0034] The locking part 54 can be held between the supports 63 of the upper housing 61 and the lower housing 62. The supports 63 can face the upper housing 61 and support the set screw 64. The set screw 64 only needs to contact the locking part 54. The locking part 54 does not require the formation of a threaded hole. This can shorten the machining process for the locking part 54 and reduce manufacturing costs. Furthermore, the locking part 54 is formed with a groove 68 that receives the tip of the set screw 64 and prevents the locking part 54 from falling out from between the upper housing 61 and the lower housing 62. The groove 68 can reliably prevent the locking part 54 from falling out from between the upper housing 61 and the lower housing 62.

[0035] When the tool adapter 27 according to this embodiment is coupled to the robot adapter 26, the positioning pins 55 of the robot adapter 26 are fitted into the positioning holes 56 of the coupling surface 28. Since high strength is ensured in the upper housing 61, the upper housing 61 can favorably hold the positioning pins 55 in the positioning holes 56. If the upper housing 61 were molded uniformly from a solid material with the second strength, the strength of the positioning holes 56 would have to be reinforced with bushings.

[0036] 15 Robot arm 16 Robot tool 25 Automatic tool changer 26 Robot adapter 27 Tool adapter 28 Coupling surface (of tool adapter) 35 Cam (cam member) 54 Lock part 55 Positioning pin 56 Positioning hole 57 Connecting part 61 Upper housing 62 Lower housing 63 Support 64 Set screw 66 Space 67 Step 68 Groove

Claims

1. A tool adapter that is connected to a robot tool and detachably connected to a robot adapter that is connected to a robot arm, comprising: an upper housing formed from a solid material of a first strength and having an upward coupling surface that is coupled to the robot adapter from below; a lower housing formed from a solid material of a second strength smaller than the first strength and coupled to the upper housing from below to connect a connector of the robot tool to the robot tool that is coupled from below; and a lock part that is received by the upper housing from below and transmits a pressing force that presses the coupling surface against the robot adapter from a cam of the robot adapter to the upper housing.

2. The tool adapter according to claim 1, further comprising a support for supporting a set screw formed in the lower housing at an interval that ensures a path for the cam, the set screw contacting the lock part from below with its tip to apply a restraining force to the lock part.

3. The tool adapter according to claim 2, further comprising a step formed in the lower housing to define a space that is open from the surface of the support in the axial direction of the set screw.

4. A tool adapter according to claim 2, wherein the locking part is formed with a groove that receives the tip of the setscrew and prevents the locking part from falling out from between the upper housing and the lower housing.

5. A tool adapter according to claim 1, wherein the coupling surface is formed with a positioning hole for receiving a positioning pin that stands up from the robot adapter when the robot adapter is received on the coupling surface.

6. An automatic tool changer comprising the tool adapter according to claim 1 and a robot adapter.

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