Robot hand and robot device

1. A method for handling a bag-shaped object having an open end and a closed end by a robot,

the robot has:

a first finger that has a first attracting section, the first finger having first and second states that are positionally different from each other; and

a second finger that has a second attracting section, the second finger having third and fourth states that are positionally different from each other, the method comprising:

placing the bag-shaped object on a table;

attracting a first edge surface of the bag-shaped object by the first attracting section in the first state, the first edge surface being located at the open end of the bag-shaped object while the bag-shaped object is in a closed state;

moving the first finger upwardly while the first attracting section attracts the bag-shaped object so that the bag-shaped object is spaced apart from the table; and

attracting a second edge surface of the bag-shaped object by the second attracting section in the third state, the second edge surface being located at the open end of the bag-shaped object while the bag-shaped object is in the closed state, the second edge surface being opposite to the first edge surface, wherein

the first finger and the second finger are respectively in the second and fourth states so that the bag-shaped object is in an open state.

2. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 1 ,

wherein the first finger has a pressure sensor.

3. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 1 ,

wherein each of the first and second fingers has:

a first knuckle that is supported to a base and a second knuckle that is supported to the first knuckle section;

a drive member that includes a male screw that is rotatable around a screw axis by a drive source and a female screw that is screw-coupled with the male screw and moves in an axial direction of the screw axis according to rotation of the male screw, in which the female screw and the first knuckle are connected to each other so that the first knuckle moves in association with movement of the female screw; and

a link that connects the first knuckle and the second knuckle so that the second knuckle moves in association with movement of the first knuckle.

4. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 3 ,

wherein the link includes:

a first connector that connects the base and the first knuckle so that the first knuckle is rotatable around a first axis that is parallel to a tangential line of a virtual circle centering around a reference axis; and

a second connector that connects the first knuckle and the second knuckle so that the second knuckle is rotatable around a second axis that is parallel to an axial direction of the first axis.

5. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 3 ,

wherein the link includes a locking member that is locked to a first connection state where the first knuckle and the second knuckle form an angle of 180°.

6. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 4 ,

wherein the base includes a planar surface that intersects with the reference axis,

wherein the planar surface is provided at an end in an axial direction of the reference axis, and

wherein each of the first and second fingers is disposed so that the first knuckle and the second knuckle protrude upward in an extending direction of the reference axis with respect to the planar surface according to rotation of the first knuckle.

7. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 5 ,

wherein the planar surface has a frictional coefficient higher than that of a front surface of each of the first and second fingers.

8. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 3 ,

wherein the base is connected to a multi-axial arm.

9. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 8 ,

wherein the multi-axial arm is configured with a plurality of multi-axial arms.

10. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 1 , further comprising:

a third finger that has a third attracting section, the third finger having the third and fourth states,

wherein when the second edge surface of the bag-shaped object is attached by the second attracting section in the third state, the second edge surface of the bag-shaped object is attached by the third attracting section, and

the first finger is in the second state and the second and third fingers are in the fourth state so that the bag-shaped object is in an open state.

11. The method for handling a bag-shaped object having an open end and a closed end by a robot, according to claim 10 ,

wherein the first, second, and third attracting sections respectively include first, second, and third attracting pads, and

the first, second, and third attracting pads are respectively attached to tips of the first, second, and third fingers.