JP2697268B2 - Robot hand - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a set including a pair of fingers for gripping a work having one joint, and particularly in a narrow place, a work for gripping a work and inverting the work upside down and placing and inserting the work at a predetermined position. The present invention relates to a robot hand capable of facilitating an operation.

[Prior art]

A conventional example will be described below with reference to the drawings. FIG. 4 is a side view of a robot apparatus to which a conventional robot hand is attached, and FIG. 5 is a front view of the conventional robot hand and its periphery. In FIG. 4, a conventional robot hand without a reference numeral is attached via a wrist 12 to the distal end of a final stage arm of a four-axis horizontal articulated robot device 11. This conventional robot hand mainly includes a hand base 13 and fingers 14. As shown in FIG. 5, the fingers 14 are a pair of members provided on the hand base 13 so as to open and close. As shown in FIG. 4, the conventional robot hand can rotate within a range of two right angles from a position indicated by a solid line in the center to each position indicated by a broken line on the right and left via a wrist portion 12. FIGS. 6 (a) and (b) show the operation steps of the conventional example. FIG. 1A shows a work 10 on a mounting surface C, which is provided with a finger provided on a base 13 of a conventional hand.
FIG. 14B shows a case where the workpiece 10 is gripped from the right lateral direction, and FIG. 14B shows a case where the workpiece 10 is placed upside down on another placement surface D. During the transition from FIG. 1A to FIG. 1B, the work 10 is turned upside down by two counterclockwise rotations of the wrist 12. Meanwhile, the wrist 12 is moved by the unlabeled arm (see FIG. 4).

[Problems to be solved by the invention]

The conventional techniques described above have the following disadvantages. FIG. 7 is a side view showing a disadvantage in operation of the conventional example, and shows an operation of taking out the work 10 housed in the returnable box 20 by grasping it with the fingers 14. Since the work 10 is stored in the returnable box 20 without sufficient space, the wrist 12 hits the peripheral wall of the returnable box 20 when the fingers 14 are to be gripped.
Inability to approach 10. FIG. 8 is a side view of another conventional example excluding the above-mentioned disadvantages. In this other conventional example, an L-shaped finger 15 is used so that the work 10 can be gripped even in a narrow space. In other words, the hand is replaced with a special hand having fingers suitable for the holding, placing and inserting operations. As described above, exchanging the hands according to the work brings a disadvantage in terms of cost for preparing various kinds of hands and a disadvantage in terms of an increased number of work steps. An object of the present invention is to solve the above problems of the prior art, and to use a small finger with a simple structure, particularly in a narrow place, and to place a work at a predetermined position by turning the work upside down and turning the work upside down. An object of the present invention is to provide a robot hand capable of facilitating a setting operation such as insertion.

[Means for Solving the Problems]

In order to solve this problem, a robot hand according to the present invention includes first and second fingers, and one first finger grips a workpiece on a hand base fixed at one end to an arm tip. The other second finger is pivotally connected at one end to the other end of the first finger and pivotally about an axis perpendicular to the other end of the second finger. A pair of fingers in which two fingers are opposed to each other so as to share the rotation axis; and the second finger is restrained and released at a predetermined angular position with respect to the first finger. Position restraint means capable of
For example, means having positioning pins detached by an actuator, or pressing,
Means for providing an isolated friction plate; and in the state where the restraint is released from the first finger, the second finger side is brought into contact with the arm by the action of gravity or with a stationary object in a working space. A controller configured to cause the second finger to assume the predetermined angular position with respect to the first finger by using gravity or abutting, and then restrict the second finger to the position restricting means.

[Action]

As a preparation stage for gripping, in the state where the constraint on the first finger is released, the position and the posture of the arm are controlled,
The second finger is brought into contact with a stationary object in the working space by the action of gravity or after taking a predetermined angular position suitable for gripping the workpiece with respect to the first finger by utilizing or contacting with the gravity, and then by the position restricting means. Be bound. Next, the workpiece is gripped and then transported. The placement and insertion of the gripped work at a predetermined position are performed after restraining at a predetermined angle position suitable for mounting and inserting the work according to the preparation stage of gripping.

【Example】

An embodiment of a robot hand according to the present invention will be described below with reference to the drawings. 1A and 1B relate to the first embodiment, in which FIG. 1A is a side view of the main part, and FIG. 1B is a sectional view of the main part. In the first embodiment, each finger includes first and second fingers which are rotatably connected at their ends, and
Position restriction means for restricting the angular position of the second finger with respect to the finger is provided on the first finger side. In FIG. 1, reference numeral 1 denotes a first finger, which is provided on a hand base (not shown) (see reference numeral 13 in FIGS. 4 and 5) so as to be capable of opening and closing. Although the number of fingers is a pair, only one is shown here. Reference numeral 2 denotes a second finger, one end of which is rotatably connected to an end of the first finger 1. Reference numeral 4 denotes a pneumatic cylinder fixed to the first finger 1 as a position restricting means, and a portion of the piston protruding outward is a positioning pin 5 (see FIG. 1 (b)). The positioning holes 6 corresponding to the pins 5 are equally arranged at four positions on the same circumference around the rotation axis of the second finger 2 as indicated by broken lines in FIG. The second finger 2 cannot rotate by itself, but is rotated by force by contact with an object fixed in the work space by the robot arm or by gravity. When the second finger 2 is at a predetermined angular position with respect to the first finger 1, the pin 5 is driven by the pneumatic cylinder 4, and the pin 5 is fitted into the corresponding hole 6 to be restrained and positioned. A second embodiment will be described with reference to FIG. 1A is a side view of the main part, and FIG. 2B is a cross-sectional view of the main part, corresponding to FIGS. 1A and 1B, respectively. The difference between the second embodiment and the first embodiment is that
The position restricting means is of a solenoid type instead of a pneumatic cylinder type. As shown in FIG. 2 (b),
A portion of the solenoid 8 that protrudes outward from the plunger is a positioning pin 9. The same members as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The operation of each of the first and second embodiments will be described with reference to FIG. FIG. 3 relates to the common operation of the first and second embodiments, and (a) to (g) are operation process diagrams of the respective embodiments. The operation shown in FIG. 3 is performed as shown in FIG.
Work 10 placed side by side in
It is to hold or set it on the bottom of a narrow recess as shown in FIG. FIG. 4A shows a preparatory operation for gripping, in which the second finger 2 is pressed against the contact surface A, and the first and second fingers 1 and 2 are positioned so that the angles thereof become a right angle, and are restrained. I do. Here, a hand composed of the hand base 13 and a pair of fingers including the first and second fingers 1 and 2 connected via the joint 3 is fixed to the wrist 12. Note that position restraining means such as a pneumatic cylinder and a solenoid provided in the finger are not shown. As shown in FIG. 3B, the fingers are inserted into the narrow gaps of the box 20, and are moved to the left to grip the work 10.
Next, as shown in FIG. 4C, while lifting the same, the pin of the position restraining means is pulled out to release the joint 3 and let the gravity move, and then the wrist 12 is rotated as shown in FIG. Then, the first finger 1 is made horizontal. Next, as shown in FIG. 3E, the left side surface of the work 10 is pressed against the contact surface B, and the first and second fingers 1 and 2 are positioned at right angles and then restrained. Then, the wrist portion 12 is rotated to make the first finger 1 vertical, the work 10 is turned upside down as shown in FIG. End the operation. By the above operation, the joint 3 is shown in FIGS.
Is in a state where it can rotate freely.
May vibrate. If this is not desirable, the operation can be performed as shown in FIG. In FIG. 7G, after the work 10 is lifted from the above-described view of FIG. 7B, the wrist 12 is rotated while pressing the left side surface of the work 10 against the contact surface B, and the dash-dotted arc is displayed. The finger is moved along the trajectory, and the finger is set to the posture indicated by the broken line. Then, the wrist 12 is rotated, and the work 10 is placed on the bottom surface of the recess with the posture shown in FIG. During the above operation, the work 10 does not vibrate. However,
There is a drawback that moving the wrist 12 along an arc trajectory requires a slightly complicated control. In each of the first and second embodiments, the position restricting means has a positioning pin, and is fitted into a corresponding positioning hole on the other side. Instead of this method, it is also possible to use a position restricting means of a method in which a friction member is pressed toward a partner and the position is restricted by the frictional force.
The advantage of this friction method is that the angular position does not need to be determined in advance and is free. On the other hand, the disadvantage is that the binding force is not as reliable as with a pin.

【The invention's effect】

As described above, in the present invention, as a preparation stage for gripping, in the state where the constraint on the first finger is released, the second finger is moved by the action of gravity or by the control of the position or posture of the arm. A predetermined angle position suitable for gripping the workpiece with respect to the first finger by utilizing or contacting with the fixed object, and then being restrained by the position restraining means. In this state, the workpiece is gripped, and then conveyed. The setting such as placing and inserting the gripped work at a predetermined position is performed after restraining at a predetermined angular position suitable for mounting and inserting the work according to the preparation stage of gripping. Therefore, according to the present invention, the following excellent effects are obtained as compared with the prior art. (1) Since the tips of the fingers are movable, the robot operation for moving and placing the work upside down can be performed reliably, safely, and quickly, which is particularly suitable for work in a narrow place. (2) Since the structure is simple, small and light, the operability can be improved and the cost can be reduced. (3) Especially when working in a narrow place, it is not necessary to replace the special hand for the work, shortening the work man-hour,
The cost of the entire apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 relates to a first embodiment according to the present invention, (a) is a side view of the main part, (b) is a cross-sectional view of the main part, and FIG. 2 is a second embodiment according to the present invention. (A) is a side view of the main part, (b) is a cross-sectional view of the main part, and FIG. 3 is a diagram showing common operations of the first and second embodiments.
(A) to (g) are the respective operation process diagrams, FIG. 4 is a side view of a robot apparatus to which a conventional robot hand is attached, FIG. 5 is a front view of a conventional robot hand and its surroundings, and FIG. Regarding the operation of the conventional example, FIGS. 7 (a) and 7 (b) show respective operation process diagrams, FIG. 7 is a side view showing an operational defect of the conventional example, and FIG. 8 is a side view of another conventional example. A, B: contact surface, C, D: mounting surface, 1, 7: first finger, 2: second finger, 3: joint, 4: pneumatic cylinder, 5, 9: pin, 6: hole , 8: solenoid, 10: work, 20: return box.

Claims (3)

(57) [Claims] A first finger provided at one end of a hand base fixed to an end of an arm so as to be capable of gripping a workpiece, and a second finger provided at the other end thereof; The finger is connected at one end thereof to the other end of the first finger so as to be rotatable around an axis perpendicular to the axis thereof, and the other end of the finger has a work holding portion.
A pair of fingers arranged opposite to each other so as to share the rotation axis; and position restraint means capable of restraining and releasing the second finger at a predetermined angular position with respect to the first finger. In the state where the restraint is released from the first finger, the second finger side is brought into contact with the arm by the action of gravity or with a stationary object in a work space, and the first finger is brought into contact with the arm by utilizing or contacting the gravity. A controller for causing the second finger to assume the predetermined angular position with respect to the finger, and then restricting the second finger to the position restricting means. 2. The robot hand according to claim 1, wherein the position restricting means includes a positioning pin detachable by an actuator. 3. The robot hand according to claim 1, wherein the position restraining means includes a friction plate pressed and isolated by an actuator.