Robot hand

Abstract

To provide a robot hand in which claws are not opened by a reaction force even if a gripping force of the claws is weak when a robot performs a fastening work or the like.SOLUTION: A robot hand includes: a hand main body attached to a distal-end part of a robot arm; a plurality of claws provided to protrude from the hand main body and configured to move between an open position at which the claws are separated from each other and a closed position at which the claws are close to each other, thereby gripping a to-be-gripped object at the closed position; and a lock member that is positioned around the plurality of claws at the closed position, thereby coming into contact with the plurality of claws when a force in a direction of the open position acts on the plurality of claws, and restricting movement of the plurality of claws.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a technique for preventing the claws of a robot hand from accidentally opening. [Background technology]

[0002] Industrial robots are used in manufacturing sites for various products. Robots equipped with robot hands at the ends of their robot arms perform various tasks, such as gripping and moving parts with the claws of the robot hand, and gripping and rotating fastening members such as screws with the claws to fasten them to other members. The gripping force of the claws that grip parts is strong, and if a human's finger is caught in the robot's claws, it can lead to serious injury, so it has been common to restrict humans from entering the robot's workspace.

[0003] In order for a robot to perform a wider variety of tasks, it can be effective for it to work in collaboration with humans. However, in the case of a collaborative robot working in collaboration with humans, it is necessary to set the gripping force of the claws to be weak in case a human's finger or other body part becomes caught in the collaborative robot's claws. Summary of the Invention [Problem to be solved by the invention]

[0004] When a collaborative robot with a weak gripping force rotates to tighten a fastening member such as a screw, if you try to tighten it with a strong force, the jaws may open due to the reaction force of the tightening. However, since the gripping force of the jaws of a collaborative robot is limited, there is a problem that it cannot perform fastening work that requires a strong force. In addition to fastening work, there is also a problem that the jaws open when a force in the opening direction is applied to the jaws.

[0005] An object of the present disclosure is to provide a robot hand that, when the robot performs tightening work or the like, does not cause the claws to open due to the force acting on the claws even if the gripping force of the claws is weak. [Means for solving the problem]

[0006] The robot hand of the present disclosure includes a hand body attached to a tip of a robot arm, a plurality of claws protruding from the hand body and movable between an open position in which they are spaced apart from each other and a closed position in which they approach each other to grasp an object to be grasped in the closed position, and a locking member positioned around the plurality of claws in the closed position to come into contact with the plurality of claws and restrict movement of the plurality of claws when a force is applied to the plurality of claws in the direction of the open position. The locking member has a rectangular frame shape surrounding the plurality of claws.

[0007] The robot hand of the present disclosure includes a hand body attached to a tip of a robot arm, a plurality of claws protruding from the hand body and movable between an open position in which they are spaced apart from each other and a closed position in which they approach each other to grasp an object to be grasped in the closed position, and a locking member positioned around the plurality of claws in the closed position to come into contact with the plurality of claws and restrict movement of the plurality of claws when a force is applied to the plurality of claws in the direction of the open position. The locking member has a rectangular frame shape surrounding the plurality of claws and has a notch in part of the frame shape.

[0008] The robot hand of the present disclosure includes a hand body attached to a tip of a robot arm, a plurality of claws protruding from the hand body and movable between an open position in which they are spaced apart from each other and a closed position in which they approach each other to grasp an object to be grasped in the closed position, and a locking member positioned around the plurality of claws in the closed position to come into contact with the plurality of claws and restrict movement of the plurality of claws when a force is applied to the plurality of claws in the direction of the open position. The locking member is movable between a locked position located around the multiple claws and an unlocked position not located around the multiple claws, and the multiple claws are formed with engagement portions that engage the locking member in the locked position, and the engagement portions are formed in multiple numbers according to the size of the object to be grasped. Effect of the Invention

[0009] According to the present disclosure, by positioning a locking member around multiple claws in the closed position, even if a force in the direction of opening the claws acts on the claws due to a tightening reaction force or the like, the claws are restricted from moving toward the open position, so that various tasks can be performed reliably without the claws accidentally opening even if the gripping force of the claws is weak. [Brief description of the drawings]

[0010] [Figure 1]FIG. 2 is a perspective view showing an entire robot hand. [Diagram 2] FIG. [Diagram 3] FIG. 13 is a diagram showing a state in which a workpiece is gripped by the jaws. [Figure 4] 13A and 13B are diagrams showing a state in which the claw is locked by the locking member. [Diagram 5] 5A and 5B are schematic diagrams illustrating an example of a locking member. [Figure 6] 5A and 5B are schematic diagrams illustrating an example of a locking member. [Figure 7] 5A and 5B are schematic diagrams illustrating an example of a locking member. [Figure 8] 5A and 5B are schematic diagrams illustrating an example of a locking member. [Figure 9] 5A and 5B are schematic diagrams illustrating an example of a locking member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment that is an example of the present disclosure will be described with reference to the drawings.

[0012] FIG. 1 is a perspective view of a robot hand 1 attached to the tip of a robot arm. The robot hand 1 is provided at the tip of the robot arm so as to be rotatable around the axis of the robot arm. The robot arm can also bend and extend and rotate around its joints. By bending and extending and rotating the joints of the robot arm, the robot hand can move along a predetermined trajectory to perform a predetermined task.

[0013] The robot hand 1 has a hand body 10 attached to the tip of the robot arm, a pair of claws 2, 2 that protrude from the hand body 10 and can be opened and closed by moving closer and farther apart relative to each other, a locking member 3 in the shape of a roughly rectangular frame, and an air cylinder 4 as a driving means for moving the locking member 3 between an unlocked position located on the outer periphery of the hand body 10 and a locked position located on the outer periphery of the pair of claws 2, 2.

[0014] The pair of claws 2, 2 are configured to be movable in parallel with the hand body 10 by a driving means (not shown) provided on the hand body 10, so that they can approach and move away from each other to open and close. As the driving means, a known driving means such as an air cylinder or an electric actuator is used.

[0015] 2 shows the details of one of the pair of claws 2, 2. A gripping surface 21 is formed on the side facing the other claw 2 (the right side in the drawing). A plurality of step portions (an example of an engagement portion) are formed on the side of the claw 2 opposite the gripping surface 21 (the left side in the drawing). The plurality of step portions are formed by alternating horizontal surface portions 22, 24, 26 and vertical surface portions 23, 25, 27 from the bottom. Furthermore, an inclined surface portion 28 (an example of a tapered portion) and a vertical surface portion 29 are formed continuously on the vertical surface portion 27. The vertical surface portions 23, 25, 27, 29 are formed at positions spaced apart from the gripping surface 21 by L1, L2, L3, L4, respectively.

[0016] The pair of claws 2, 2 have the same shape and are provided on the hand body 10 so that their respective gripping surfaces 21, 21 face each other. When the pair of claws 2, 2 approach each other, a workpiece is gripped between the opposing gripping surfaces 21, 21.

[0017] Returning to FIG. 1, the locking member 3 comprises a frame body 31 formed in a frame shape so as to surround the hand body 10 and the pair of claws 2, 2, and a flange 32 formed to protrude horizontally from the frame body 31.

[0018] The air cylinder 4 has a cylinder portion 41 attached to the side of the hand body 10, and a piston 42 is disposed so as to extend and retract downward from the cylinder portion 41. The piston 42 is coupled to the flange 32 of the locking member 3. As the piston 42 extends and retracts, the locking member 3 moves between an unlocked position where it surrounds the hand body 10 and a locked position where it surrounds the pair of jaws 2, 2.

[0019] Next, the operation of the robot hand 1 will be described with reference to FIGS. 3 and 4. Here, let the inner diameter in the left-right direction of the frame body 31 in FIG. 3 be L, and the length of the workpiece in the same left-right direction be W. With the lock member 3 in the unlocked position and the pair of claws 2, 2 in the open position, the robot hand 1 moves so that the pair of claws 2, 2 sandwich the workpiece 100 and are positioned on both sides. Next, the pair of claws 2, 2 move closer to each other by the driving means to grip the workpiece 100 (FIG. 3). At this time, the distance between the pair of vertical surfaces 23, 23 is 2×L1 + W, the distance between the pair of vertical surfaces 25, 25 is 2×L2 + W, the distance between the pair of vertical surfaces 27, 27 is 2×L3 + W, and the distance between the pair of vertical surfaces 29, 29 is 2×L4 + W. Also, the distance between the pair of inclined surfaces 28, 28 decreases as it goes upward in FIG. 3 between 2×L3 + W and 2×L4 + W. Then, as the piston 42 extends, the lock member 3 descends from the unlocked position to the locked position. At this time, the lock member 3 descends to the position of the vertical surface or the inclined surface whose distance from each other matches the inner diameter L in the left-right direction of the frame body 31 among the vertical surfaces 23, 25, 27, 29 or the inclined surface 28. In the examples of FIGS. 3 and 4, since the inner diameter in the width direction of the frame body 31 and the distance between the pair of vertical surfaces 27, 27 both match L, the frame body 31 descends to the position of the vertical surfaces 27, 27 and abuts against the horizontal surfaces 26, 26 directly below the vertical surfaces 27, 27 and stops. At this time, the inner side surfaces in the width direction of the frame body 31 face each other so as to fit into the vertical surfaces 27, 27 of the pair of claws 2, 2.

[0020] Also, depending on the size of the workpiece 100, the frame body 31 abuts against the inclined surface 28 and stops descending. Since the inclined surface 28 is formed by continuously inclining with the distance from the gripping surface 21 being between L3 and L4, when W is in the range of L - 2×L3 < W < L - 2×L4, the frame body 31 engages with and locks to the inclined surface 28. That is, if the inclined surface 28 is formed, it is possible to correspond steplessly to the size of the workpiece 100 without forming a plurality of stepped portions corresponding to the size of the workpiece 100.

[0021] Next, the robot hand 1 and the workpiece 100 move as the robot arm moves. Then, a predetermined task is performed, such as assembling the workpiece 100 to another member, or fastening and fixing the workpiece 100 to another member. At this time, depending on the task, a large reaction force acts on the gripping surfaces 21, 21 of the pair of claws 2, 2 in a direction in which the pair of claws 2, 2 open. However, since the frame body 31 of the locking member 3 is positioned so as to face the vertical surfaces 27, 27, the locking member 3 restricts the movement of the pair of claws 2, 2, and prevents the pair of claws 2, 2 from opening.

[0022] 5 to 7 are plan views that typically show various forms of the locking member 3. In Fig. 5, the locking member is rectangular in shape surrounding the pair of claws 2, 2, but the shape of the locking member is not limited to a rectangle, and it may be U-shaped as in Fig. 6, or separate left and right members as in Fig. 7, or may have any shape that faces the side surfaces of the pair of claws 2, 2 in the opening direction.

[0023] 8 and 9 are plan views that typically show the form of the locking member 3 when the robot hand has three claws 2, 2, 2. The locking member 3 may have a shape that surrounds the three claws 2, 2, 2 (a hexagon in FIG. 8) or may have a shape that is divided corresponding to each of the claws 2, 2, 2 as in FIG. 9.

[0024] Although the above description has been given with reference to the drawings, the invention according to the claims of the present application is not limited to the above embodiment. For example, the locking member may be of any shape as long as it is positioned opposite the side surface of the claw in the opening direction to restrict the movement of the claw in the opening direction. In addition, the side surface of the claw in the opening direction does not necessarily have to be a step shape consisting of a horizontal surface portion and a vertical surface portion, and may have an inclined surface portion instead of the horizontal surface portion, or may be composed only of a vertical surface portion or an inclined surface portion. Furthermore, a driving means for moving the locking member is not necessarily required, and may be a manual type. In the above embodiment, the unlocked position is located on the base end side of the robot hand and the locked position is located on the tip end side of the robot hand, but the unlocked position may be located on the tip end side of the robot hand and the locked position may be located on the base end side of the robot hand. [Industrial Applicability]

[0025] The present disclosure is applicable to robot hands of various robots. [Explanation of symbols]

[0026] 1. Robot Hand 2 Claws 23, 25, 27, 29 Vertical section 28 Slope section 3 Locking member 4 Air Cylinder 10 Hand body 100 Work

Claims

1. A hand body attached to a tip of the robot arm; a plurality of claws provided to protrude from the hand body, the claws being movable between an open position in which they are spaced apart from each other and a closed position in which they approach each other and capable of gripping an object to be gripped at the closed position; a locking member that is positioned around the plurality of claws in the closed position and that comes into contact with the plurality of claws to restrict movement of the plurality of claws when a force is applied to the plurality of claws in the direction of the open position; A robot hand equipped with

2. The locking member has a rectangular frame shape surrounding the plurality of claws. The robot hand according to claim 1 .

3. The locking member has a rectangular frame shape surrounding the plurality of claws, the rectangular frame shape having a notch in a part of the frame. The robot hand according to claim 1 .

4. The locking member is provided to be movable between a locked position in which the locking member is positioned around the plurality of claws and an unlocked position in which the locking member is not positioned around the plurality of claws. The robot hand according to any one of claims 1 to 3.

5. The plurality of claws are formed with engagement portions that engage the locking member at the lock position. The robot hand according to claim 4.

6. The engaging portion is formed in a plurality of portions according to the size of the object to be grasped. The robot hand according to claim 5.

7. The engaging portion is formed in a plurality of positions so as to be spaced apart from the gripping surface that grips the object toward the tip of the claw. The robot hand according to claim 5.

8. The engagement portion has a step portion. The robot hand according to claim 6.

9. The engagement portion has a tapered portion. The robot hand according to claim 6.

10. A lock member moving means for moving the lock member is provided. The robot hand according to claim 4.

11. a claw opening / closing drive means for opening and closing the plurality of claws, and a lock member moving means for moving the lock member, After the claw opening / closing drive means moves the claw to a closed position, the locking member moving means moves the locking member from an unlocked position to a locked position. The robot hand according to claim 4.

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