JPH0677911B2 - Robot hand - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot hand particularly suitable for handling a work of a special shape having poor stability.

2. Description of the Related Art For example, a robot hand used for handling a work in a forging process has a structure shown in FIGS. 4 and 5.

As shown in FIGS. 4 and 5, the hand body 2 is attached to the arm 1 of the industrial robot,
A pair of long and short arm bars 3 and 4 are arranged in parallel with each other. Fingers 5 and 6 are attached to the tips of the arm bar kings 3 and 4, respectively.

The arm bars 3 and 4 are slidably supported by the hand main body 2 via bushes 7, and racks 3a and 4a are formed on one side of each arm bar 3 and 4. These racks 3a, 4a mesh with a pinion 8 rotatably arranged between the arm bars 3, 4.

A cylinder 9 as an actuator is arranged between the arm bars 3 and 4. The piston rod 9a of the cylinder 9 is connected to the arm bar 3 on one side through a bracket 10.
It is connected to the end of 4.

Therefore, when the piston rod 9a slides in the direction in which it is drawn into the cylinder tube 9b, both arm bars 3 and 4 slide in opposite directions in synchronization with each other. That is, the arm bar 3 slides in the A direction, the arm bar 4 slides in the B direction, and the fingers 5 and 6 work W.
Then, the work W is taken out from the die 11.

Here, as a peculiarity of the work in the middle of forging, a flash F is generated in a part thereof as shown in FIG. 4, so in the case of the above robot hand, the flash F is grasped by the finger 6 There is.

Problems to be Solved by the Invention When the work W gripped by the above robot hand is handled and released in the die of the next process, since there is a flash F as shown in FIG. 4, it is released by the finger 5. The release by the finger 6 will be delayed than the release. Therefore, in combination with the fact that the work W itself has a special shape having the rod portion Q, the work W falling from the hand with respect to the mold 11 is inclined, and the work W is smoothly inserted into the mold 11. I can't.

The present invention is intended to provide a robot hand that can sufficiently cope with a work having a special shape as described above.

Means for Solving the Problems The present invention is a hand capable of releasing the portion corresponding to the flash in advance when the work having the flash described above is targeted.

Specifically, in a robot hand that grips a predetermined work by sliding a pair of parallel arm bars in opposite directions, a positioning block provided on the hand main body to position the hand main body and the work, and a hand main body. A first arm bar and a second arm bar that are slidable in the axial direction in parallel with each other; and an assist cylinder that is provided in the hand main body and constantly urges the first arm bar in a direction to separate the first arm bar from the work , The cylinder tube is integrally connected to the first arm bar, and the piston rod is connected to the second arm bar. The force generated by the assist cylinder is overcome to slide both arm bars to directly contact the work. It is composed of a cylinder that performs a gripping operation until it comes into contact with and stops.

The first arm bar, the assist cylinder, and the cylinder are arranged in parallel with each other while maintaining the parallel state of the three.

Action According to the present invention, when one arm bar reaches the gripping motion limit or the releasing motion limit, the other arm bar shifts to the initial motion or the releasing motion under the reaction force.

Therefore, in the case of targeting a work involving the occurrence of flash as described above, the posture of the work after the release can be improved by advancing the release timing of the portion corresponding to the flash.

Embodiment FIG. 1 to FIG. 3 are views showing a more specific embodiment of the present invention, and exemplify a robot hand for the forging work described above. 1 and 2 show a state in which the work W is gripped, and FIG. 3 shows the work W.
Shows the state in which each is released.

1 and 2, a substrate 20 as a hand body is integrally attached to the arm 1 of the industrial robot. Substrate 20 has supporting portions 20a, 20b protruding from its side.
including.

The support portion 20a includes a pair of first arm bars 21 parallel to each other.
Are slidably supported via bushes 22.
A holder plate 23 is fixed to one end of each arm bar 21, and a finger 24 is fixed to the other end. A slit 25 corresponding to the flash F of the work W is formed on the finger 24.

An assist cylinder 26 is disposed on the lower surface of the support portion 20a, and its piston rod 26a is connected to the holder plate 25. Air is constantly fed into the head side chamber of the assist cylinder 26, and acts so as to push out the piston rod 26a with respect to the cylinder tube 26b.
That is, the assist cylinder 26 acts as an air spring, and constantly biases the arm bar 21 in the direction in which the finger 24 separates from the work W.

Further, an air cylinder 27 for holding or releasing a second arm bar 28, which will be described later, in addition to the first arm bar 21 is fixed to the holder plate 23. This air cylinder 27 has a diameter (pressure receiving area) that is larger than that of the assist cylinder 26.
Of the air cylinder 27, the assist cylinder 26, and the first arm bar 21 are arranged so as to overlap each other in the diameter direction of the air cylinder 27.

The support portion 20b has a pair of second arm bars 28 parallel to each other.
Is slidably supported via bush 29.
A holder plate 30 is fixed to one end of each arm bar 28, while a finger 31 is fixed to the other end. Furthermore, the holder plate 30 is an air cylinder 27.
Is connected to the piston rod 27a.

Therefore, the action of the air cylinder 27 causes the second arm bar 28 to slide and the finger 31 to grip or release the work W.

A pair of guide pins 32 and a positioning block 33 are fixed to the lower surface of the support portion 20b. Then, the guide pin 32 and the positioning block 33 are used for the hand and the work W.
Will be positioned relative to.

A stopper 34 is provided at a position facing the holder plate 23, and has a function of restricting the slide limit position of the first arm bar 21.

Further, 11 is a die for forging, and the forged work W is levitated by a predetermined amount by a knockout pin 13 which is moved upward by the rotation of the eccentric cam 12.

The robot hand thus configured operates as follows.

FIG. 3 shows a state before the work W is gripped, and the work W is floated from the die 11 by a predetermined amount by the action of the knockout pin 13 described above. In this state, the hand is pressed from directly above the work W, and the work W is positioned by the guide pin 32 and the positioning block 33.

When the air cylinder 27 is actuated in the direction of pulling its piston rod 27a into the cylinder tube 27b, the second arm bar 28 slides in the B direction together with the finger 31,
One end of the work W is gripped by the finger 31 and one positioning block 33.

If the air cylinder 27 continues to operate after the finger 31 grips the work W, the thrust force output from the air cylinder 27 overcomes the thrust force of the other assist cylinder 26.
On the contrary, the first arm bar 21 slides in the A direction together with the cylinder tube 27b and the holder plate 23. As a result, the finger 24, which is integral with the first arm bar 21, and the positioning block 33 on the other side grip a portion of the work W corresponding to the flash F.

That is, assuming that air is introduced into the assist cylinder 26 and the air cylinder 27 from the same pressure source, the air cylinder 27 is the thrust force of the cylinder due to the difference in diameter (pressure receiving area) of both cylinders 26 and 27. growing. Therefore, the gripping by the finger 31 precedes, and the finger
Wait for 31 gripping operations to complete and wait for the other finger 25
Shifts to a gripping operation. As described above, the work W is firmly gripped as shown in FIG. Then, the gripped work W is handled by the die in the next step.

Next, the operation of releasing the work W will be described with reference to FIG. 1 for convenience.

When the chamber of the air cylinder 27 into which air has been introduced until then is released to the atmosphere, the thrust force of the air cylinder 27 and thus the gripping force of the finger 31 are reduced. Then, the thrust of the assist cylinder 26 again overcomes the thrust of the air cylinder 27, and the holder plate 23 moves in the B direction together with the cylinder tube 27b and the first arm bar 21 while the finger 31 remains in contact with the work W. Moving. As a result, the finger 24 separates from the work W and releases the work W.

When the holder plate 23 comes into contact with the stopper 34, the second arm bar 28 slides in the direction A in response to the reaction force thereof. As a result, the finger 31 separates from the work W and releases the work W.

In this case, the work W is released by the finger 24 first, and the work W is released by the finger 31 later, but the center of gravity of the work W is on the right side of FIG. 1 due to its shape. Therefore, the work W is smoothly inserted into the mold 11 without tilting. The knockout pin 13 is lowered when the work W is inserted.

EFFECTS OF THE INVENTION According to the present invention, the releasing operation of one arm bar precedes the releasing operation. Therefore, for example, even when targeting a forged work and a work of a special shape, the posture of the work after release varies. Be stable without.

Further, since the positioning block is also used, the workpiece can be reliably gripped even when the posture of the workpiece varies a little during gripping, and the workpiece is not lost as compared with the conventional case. Further, since the first arm bar, the assist cylinder, and the cylinder are arranged so as to overlap each other in the diameter direction of the cylinder while maintaining their parallel state, the total length of the robot hand can be shortened. In particular, even when a heavy work such as a forged work is gripped, the supporting rigidity is high.

[Brief description of drawings]

1 is a sectional view of a work gripping state showing an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, FIG. 3 is a sectional view of the work gripping state, and FIG. 4 is a conventional robot hand. Explanatory drawing and FIG. 5 are plan views of FIG. 20 ... substrate as hand body, 21 ... first arm bar, 24 ... finger, 26 ... assist cylinder, 27 ...
… Air cylinder, 28 …… Second arm bar, 31 …… Finger, 33 …… Positioning block, W …… Workpiece, F…
… Burr.

Claims (1)

[Claims] 1. A robot hand for holding a predetermined work by sliding a pair of parallel arm bars in mutually opposite directions, a positioning block provided on the hand main body for positioning the hand main body and the work, and a hand main body. A first arm bar and a second arm bar that are axially slidable in parallel with each other; and an assist cylinder that is provided in the hand main body and constantly urges the first arm bar in a direction to separate the first arm bar from the work. , The cylinder tube is integrally connected to the first arm bar and the piston rod is connected to the second arm bar, and both arm bars are slid by overcoming the force generated by the assist cylinder to directly contact the work. And a cylinder that performs a gripping operation until it comes into contact with and stops. A robot hand characterized in that the mubar, the assist cylinder, and the cylinder are kept in parallel with each other while the three are superposed on each other in the diameter direction of the cylinder.