Clamp device, end effector and robot

Abstract

To provide a clamp device capable of being easily installed on an end effector or the like.SOLUTION: A clamp device comprises a first arm 211, a second arm 212 and a main body part 213 is configured in such a manner that: the first arm 211 and the second arm 212 are rotatably connected via a connection member 216 penetrating through the main body part 213; ends of a torsion coil spring 215 are connected to the first arm 211 and the main body part 213; the connection member 216 is inserted into a coil portion of the torsion coil spring 215; and when the second arm 212 is rotated together with the first arm 211, one surface of a workpiece is pressed by a pressing portion 217 mounted on the tip of the second arm 212, and when it is reversely rotated, the first arm 211 and the second arm 212 return to original positions due to energization of the torsion coil spring 215.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a clamping device, an end effector, and a robot. [Background technology]

[0002] Robots are now being introduced into manufacturing lines with the aim of improving efficiency through automation that eliminates human labor. For example, robots have been introduced to automate the transfer of workpieces from one location to another (see, for example, Patent Document 1). The robot described in Patent Document 1 has an end effector attached to the tip, which grasps the workpiece and transfers it to another location. Various innovations have been made for such robots that grasp and transfer workpieces to ensure reliable gripping of the workpiece (see, for example, Patent Document 2). Patent Document 2 discloses a robot equipped with a pressing body on an arm that grasps the workpiece, and which grasps the workpiece while adjusting the pressing body. This increases the gripping force. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-138937 [Patent Document 2] Japanese Patent Publication No. 2022-142908 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, clamping devices are known for fastening a workpiece. For example, if a clamping device could be provided on the end effector of a robot such as that described in Patent Document 1, the workpiece could be gripped more firmly. Therefore, there is a demand for a clamping device that can be easily attached to an end effector, for example, since it would be possible to fasten the workpiece and increase the gripping force. [Means for solving the problem]

[0005] In order to solve the above problem, the clamping device of the present invention comprises a first arm, a second arm, and a main body, the first arm and the second arm being rotatably connected via a connecting member that passes through the main body, the first arm and the main body being connected to the ends of a torsion coil spring, the connecting member being inserted into the coil portion of the torsion coil spring, when the second arm rotates together with the first arm, a pressing portion attached to the tip of the second arm presses down on one side of the workpiece, and when the second arm rotates in the opposite direction to the rotation, the torsion coil spring is urged and the first arm and the second arm return to their original positions. [Effects of the Invention]

[0006] The clamping device according to the present invention has been made in view of the above-mentioned problems, and can be easily installed on an end effector, for example. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a side view of a robot according to an embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of an end effector according to an embodiment of the present invention. [Figure 3] FIG. 1 is a perspective view of an end effector according to an embodiment of the present invention. [Figure 4] FIG. 10 is another perspective view of an end effector according to an embodiment of the present invention. [Figure 5] FIG. 2 is a perspective view of a replacement claw according to an embodiment of the present invention. [Figure 6] 1 is a perspective view of a clamping device according to an embodiment of the present invention. [Figure 7] FIG. 2 is an exploded view of the clamping device according to the embodiment of the present invention. [Figure 8] 1A and 1B are diagrams illustrating a torsion coil spring according to an embodiment of the present invention. [Figure 9] 5A to 5C are diagrams illustrating the operation of the clamping device according to the embodiment of the present invention. [Figure 10] FIG. 10 is a perspective view illustrating an operation of the end effector according to the embodiment of the present invention gripping a workpiece. [Figure 11] FIG. 2 is a perspective view illustrating an operation of clamping a workpiece by the clamping device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, it is assumed that the clamping device according to the present invention is installed on the end effector of a robot. Note that although the reference symbols a to d may be used in the drawings, the same numbers indicate the same functions and roles.

[0009] FIG. 1 is a side view of a robot 10 equipped with an end effector to which a clamping device of the present invention is installed. As shown in FIG. 1, the robot 10 is of an articulated type, with robot arms 30a to 30c connected to each other via joints 40a to 40d. The end effector 20 is for gripping a workpiece and is connected to the robot arm 30c via joint 40d. The robot arm 30a is attached to a fixed rotation unit 50 that can rotate horizontally via joint 40a. The specific type and configuration of the robot arms and joints are not particularly limited, and any configuration may be used as long as they can be used to attach and operate end effectors.

[0010] FIG. 2 is a perspective view of an end effector 20 according to an embodiment of the present invention. As shown in FIG. 2, the end effector 20 is composed of clamping devices (210a, 210b), a gripper device 220, and gripping claws (230a, 230b). The clamping devices (210a, 210b) are symmetrical. The gripping claws (230a, 230b) are also symmetrical. The gripping claws (230a, 230b) may be made of any material that can withstand the load of the workpiece, such as aluminum or a resin such as plastic. The same applies to the clamping devices (210a, 210b).

[0011] FIG. 3 is a perspective view of the end effector 20 according to an embodiment of the present invention. As shown in FIG. 3(A), the gripping claws 230a are composed of outer claws 231a and replacement claws 232a, and the gripping claws 230b are composed of outer claws 231b and replacement claws 232b. Note that the end effector 20 shown in FIG. 1 shows the outer surface of the outer claws 231. The gripping claws (230a, 230b) are coupled to a workpiece holder 250 that accommodates and holds at least a workpiece, and are used to grip the workpiece. FIG. 4 is a perspective view of the end effector according to an embodiment of the present invention. As shown in FIG. 4, the replacement claws 232a are detachable from the outer claws 231a. Furthermore, the replacement claws 232b are detachable from the outer claws 231b. The outer claws 231 are fixed to the movable part 221 of the gripper device 220, and specifically, as shown in Fig. 3(B), the outer claws 231a are coupled to the movable part 221a, and the outer claws 231a are coupled to the movable part 221a, and move in conjunction with the movable part 221. The outer claws 231a have screw holes, and are coupled to the movable part 221a by screwing them in. The same applies to the outer claws 231b and the movable part 221b.

[0012] The gripper device 220 is equipped with a motor, which can move the movable part 221 in the ±X directions, thereby opening and closing the gripping claws (230a, 230b). The movable part 221 is made up of movable parts 221a and 221b that move in different directions. For example, when the movable part 221a moves in the +X direction shown in FIG. 3(B), the movable part 221b moves in the −X direction. The gripper device 220 may use, for example, a pneumatic gripper, which can move the movable part 221 in the X direction using compressed air.

[0013] FIG. 4 is a perspective view of the end effector 20 according to an embodiment of the present invention, illustrating the state in which the replacement claws (232a, 232b) are detached from the outer claws (231a, 231b). As shown in FIG. 4, the replacement claw 232b has two protrusions 234. The replacement claw 231b has two holes 233. The protrusions 234 are cylindrical with hemispherical tips, and the holes 233 are circular holes with a larger diameter than the cylinder. The replacement claw 232b can be attached to the outer claw 231b by inserting the protrusions 234 into the holes 233. Meanwhile, when the replacement claw 232b is attached to the outer claw 231b, the replacement claw 232b can be removed from the outer claw 231b by pulling the protrusions 234 out of the holes 233. Note that the outer claw 231b may have protrusions, and the replacement claw 232b may have holes. The present invention can be implemented even if the replacement claw and the outer claw are not detachable.

[0014] A catch cylinder can be used to more firmly connect the outer claws 231b and the replacement claws 232b. Specifically, a catch cylinder 235 is attached to the outer claws 231b, and a catch cylinder receiver 236 is attached to the replacement claws 232b. The catch cylinder 235 has an air supply port supplied via an air tube (not shown) and a tip end equipped with a steel ball. When air is supplied, the steel ball fits radially into the tip end of the catch cylinder 235. When air is not supplied, the steel ball protrudes radially from the tip end of the catch cylinder 235. The catch cylinder receiver 236 has an internal storage ring 239 that accommodates the protruding steel ball, and can engage and lock the steel ball when it protrudes from the catch cylinder 235. The tip end of the catch cylinder 235 can be inserted into or removed from the catch cylinder receiver 236 when air is supplied to the catch cylinder 235.

[0015] When attaching the replacement claws 232b to the outer claws 231b, air is supplied to the catch cylinder 235, and the replacement claws 232b are inserted into the catch cylinder receiving portions 236, and then the air supply is stopped. When the replacement claws 232b are attached to the outer claws 231b, the replacement claws 232b can be pulled out from the outer claws 231b by supplying air to the catch cylinder 235. The outer claws 231b and 232b are symmetrical to the outer claws 231a and 232a, and the outer claws 231a and 232a can also be provided with catch cylinders 235 and catch cylinder receiving portions 236 in the same way.

[0016] Figure 5 shows a perspective view of the replacement claw 232. Figure 5(A) is a perspective view of the replacement claw 232b, and Figure 5(A) is a perspective view of the replacement claw 232a. As shown in Figure 5(A), a clamp device 210b is attached to the replacement claw 232b. Also, as shown in Figure 5(B), a clamp device 210a is attached to the replacement claw 232a. The attachment position of the clamp device 210b is a position where the second arm 212 rotates and the pressing member 217 reliably abuts against the workpiece.

[0017] Figure 6 shows a perspective view of clamp device 210b according to an embodiment of the present invention. In Figure 6, the dotted line portions of torsion coil spring 215 and connecting member are seen through. Clamp device 210a is bilaterally symmetrical to clamp device 210b, and the functions of the components are the same as those of clamp device 210b.

[0018] As shown in FIG. 6, the clamp device 210b is made up of a first arm 211, a second arm 212, a main body 213, a locking member 214, a torsion coil spring 215, a connecting member 216, and a pressing member 217.

[0019] The first arm 211 and the second arm 212 are connected by a connecting member 216. The first arm 211 and the second arm 212 each have a cylindrical hollow portion, and a cylindrical connecting member 216 is inserted into and fixed to the first arm 211 and the second arm 212, respectively. The connecting member 216 is inserted into a hollow portion of the main body 213 and is rotatable within the main body 213. The connecting member 216 has a protrusion (see FIG. 7) that can be fitted into a recess (see FIG. 7) of the second arm 212.

[0020] The first arm 211 is attached to the outer claw 231b side of the main body 213. A pressing member 217 is attached to the tip of the second arm 212. A portion of the pressing member 217 is arcuate, and when the pressing member 217 rotates together with the second arm 212, it comes into contact with the workpiece and presses down one side of the workpiece from above. By using an elastic material such as resin for the pressing member 217, it can be used to handle multiple workpieces of different thicknesses.

[0021] Torsion coil spring 215 is attached between first arm 211 and main body 213. The distance between first arm 211 and main body 213 is at least greater than the coil width T (see FIG. 8(B)) of coil portion 215a. Connecting member 216 passes through coil portion 215a.

[0022] FIG. 7 is an exploded view of a clamping device according to an embodiment of the present invention. As shown in FIGS. 6 and 7, main body 213 has one or more insertion holes 218 through which bent portion 215e of torsion coil spring 215 (see FIG. 8(A)) can be inserted. For example, as shown in FIG. 7, there are three insertion holes 218-1 to -3 through which bent portion 215e of torsion coil spring 215 can be inserted. In this embodiment of the present invention, as shown in FIG. 6, bent portion 215e of torsion coil spring 215 is inserted through insertion hole 218-1. First arm 211 has one or more insertion holes 219 through which bent portion 215d of torsion coil spring 215 (see FIG. 8(A)) can be inserted, and bent portion 215d is inserted through one of insertion holes 219. This connects torsion coil spring 215 to first arm and main body 213. By providing a plurality of insertion holes, even if the free angle of the torsion coil spring 215 (see FIG. 8C) or the thickness of the workpiece changes, it is possible to flexibly respond by changing the insertion holes.

[0023] 6 and 7, locking member 214 has a plate-like shape and is screwed to main body 213. Locking member 214 locks second arm 212. Bush 261 supports connecting member 216 to ensure smooth rotation. Collar 262 is screwed to connecting member 216 to prevent connecting member 216 from sliding in the direction of the rotation axis.

[0024] 8A and 8B are diagrams showing torsion coil spring 215 according to an embodiment of the present invention. As shown in Fig. 8A, torsion coil spring 215 is composed of coil portion 215a and two arms (215b and 215c) extending tangentially from both ends of coil portion 215a. The tips of arm 215b and arm 215c have a single-stage bent structure with bent portions 215d and 215e bent at a right angle, respectively.

[0025] Fig. 8(B) is a front view of torsion coil spring 215, and Fig. 8(C) is a side view of torsion coil spring 215. As shown in Fig. 8(B), coil portion 215a is a spiral coil, and its coil width is T.

[0026] Next, the operation of the clamping device 210 will be described. First, a rectangular workpiece W having a predetermined thickness as shown in FIG. 10(A) will be described. By operating the gripper device 220 from the state shown in FIG. 10(A) to move the gripping jaws 230a and 230b, the workpiece W can be gripped as shown in FIG. 10(B). The clamping device 210b at this time is as shown in FIG. 9(A). Here, in FIGS. 9(A)-(C), the left side is a side view of the clamping device 210b as seen from +X in FIG. 2, and the right side is a side view of the clamping device 210b as seen from -X in FIG. 2. Note that FIG. 9 is a perspective view of the torsion coil spring 215.

[0027] The state shown in Fig. 9(A) is the origin position. When actuator 240b is operated in the state shown in Fig. 9(A) to extend rod 241b, the tip of rod 241b presses against first arm 211. Note that actuator 240b is installed on a stand provided on outer claw 231b as shown in Fig. 3(A). The same applies to actuator 240a.

[0028] As the rod 241b further extends, it pushes the first arm 211 to rotate clockwise, as shown on the left side of FIG. 9(B). Accordingly, the second arm 212 connected to the first arm 211 also rotates in the same direction. In the side view shown on the right side of FIG. 9(B), the second arm 212 is rotating counterclockwise. FIGS. 11(A) and 11(B) are perspective views showing the state of the clamp device 210b at this time. For ease of explanation, the gripping claws 230a are omitted from FIG. 11(A). As shown in FIG. 11(A), in the state shown in FIG. 9(B), it can be seen that the rod 241b is pushing against the groove in the first arm 211. This groove allows the contact position to slide depending on the degree of extension of the rod 241b.

[0029] When rod 240b extends further from the state shown in Figure 9(B), first arm 211 rotates further clockwise as shown in the side view on the left side of Figure 9(C), and extension of rod 240b stops at the position where pressing member 217 abuts against the workpiece. This position is called the clamp position. Note that, as shown in the side view on the right side of Figure 9(C), second arm 212 rotates further counterclockwise from the state shown in Figure 9(B).

[0030] In the state shown in FIG. 9(C), the workpiece is clamped by the pressing member 217, preventing it from moving upward (in the Z direction shown in FIG. 2). To release the clamp, the rod 240b of the actuator 240b is shortened. When the rod 240b is shortened, the first arm 211 and the second arm 212 return to their original positions while being biased by the torsion coil spring 215 so that the torsion angle of the torsion coil spring 215 narrows. As a result, the pressing member 218 that had been pressing the workpiece is released from the workpiece, and the clamp is released. When the rod 240b is further shortened, the first arm 211 and the second arm 212 return to their original positions as shown in FIG. 9(A). Note that the rod 241b is not shown in FIGS. 9(A) to 9(C).

[0031] When returning to the origin position, rod 241b separates from first arm 211 and is urged by torsion coil spring 215, urging first arm 211 of clamp device 210b shown on the right side of Fig. 9(A) in the clockwise direction, but second arm 212 is locked by locking member 214 so that it cannot rotate any further. The first arm also returns to the origin position shown in Fig. 9(A). In this way, locking member 214 can prevent vibration.

[0032] (Variation 1) In the embodiment of the present invention, as shown in FIG. 3(A), two actuators 240a and 240b are used, but it is also possible to use one actuator and connect a connecting member to the first arm 211 of each of the clamp devices 210a and 210b shown in FIG. 2, so that the rod 241 of this single actuator 240 rotates the first arm 211 of each of the clamp devices 210a and 210b.

[0033] (Variation 2) In the embodiment of the present invention, the clamping device 210 is attached to the replacement jaws 232, but this is not limited to this. If the pressing member 217 is arranged directly above the receiving portion of the workpiece on other equipment, etc., the same clamping operation as in the present invention can be performed not only with an end effector but also with other equipment.

[0034] (Variation 3) In the embodiment of the present invention, first arm 211 is rotated by rod 241 of actuator 240, but this is not limiting and it is also possible to rotate it manually and add a locking member to lock it when it has rotated to the position shown in Figure 9(C) to prevent it from returning to the original position due to the force of torsion spring 215, and when the clamp is released, the locking member is removed to return it to the original position.

[0035] (others) 10, in the embodiment of the present invention, the workpiece has a rectangular shape with a predetermined thickness, but is not limited to this and can be applied to, for example, a round workpiece by changing the shape of the workpiece holder 250. Cables, air tubes, etc. are omitted from the drawing. [Explanation of symbols]

[0036] 10. Robot 20 End Effector 30 Robot Arm 40 Joints 50 Fixed rotating part 210 Clamping device 211 First Arm 212 Second Arm 213 Main body 214 Locking member 215 Torsion coil spring 215a Coil section 215b,c Arm 215d,e Bend section 216 Connecting member 217 Holding member 218 Insertion hole 219 Insertion hole 220 Gripper device 221 Moving parts 230 Gripping claw 231 External claw 232 Replacement Claws 233 Hole 234 Protrusion 235 Catch cylinder 236 Catch cylinder receiving part 240 Actuator 241 Rod 250 Work holding part 261 Bushes - those that make connecting members easier to rotate 262 Color

Claims

1. a first arm, a second arm, and a main body; the first arm and the second arm are rotatably coupled via a connecting member that penetrates the main body portion, the first arm and the main body are connected to ends of a torsion coil spring, the connecting member is inserted into the coil portion of the torsion coil spring, When the second arm rotates together with the first arm, a pressing portion attached to the tip of the second arm presses down one surface of the workpiece, When the arm is rotated in the opposite direction to the rotation, the torsion coil spring biases the first arm and the second arm to return to their original positions. Clamping device.

2. The clamping device according to claim 1 , wherein the main body portion has a plurality of insertion holes for connecting ends of the torsion coil spring.

3. The clamping device according to claim 1 , wherein the first arm has a plurality of insertion holes for connecting ends of the torsion coil spring.

4. The clamp device according to claim 1 , wherein the first arm has a groove on a rear surface thereof, and the rotation is caused by a rod of an actuator being pressed against the groove.

5. The clamping device according to claim 1 , wherein the pressing portion is made of an elastic material.

6. The clamping device according to claim 1 or 5, wherein the tip of the pressing portion includes a circular shape.

7. The clamping device of claim 1 , further comprising a locking member attached to the body portion for locking the second arm in the original position.

8. An end effector, a first arm, a second arm, and a main body; the first arm and the second arm are rotatably coupled via a connecting member that penetrates the main body portion, the first arm and the main body are connected to ends of a torsion coil spring, the connecting member is inserted into the coil portion of the torsion coil spring, When the second arm rotates together with the first arm, a pressing portion attached to the tip of the second arm presses down one surface of the workpiece, When the arm is rotated in the opposite direction to the rotation, the torsion coil spring biases the first arm and the second arm to return to their original positions. A clamping device is provided, The clamping device is attached to a position where the pressing portion can press down on one surface of the workpiece when the workpiece is gripped.

9. The clamping device according to claim 8 , wherein the clamping device is attached to two gripping jaws for gripping the workpiece.

10. The clamping device of claim 9 , wherein the first arms of the respective attached clamping devices are coupled to one another via a connecting member.

11. A robot comprising the end effector according to any one of claims 8 to 10.

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