JPH0512118B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a hand device for an industrial robot, and in particular, when the hand device is damaged due to a failure of the robot's CPU during rotation, raising, or lowering operations of the robot arm. The present invention relates to a hand device for an industrial robot that can prevent damage to the hand device due to impact when the hand device collides with surrounding objects.

[Conventional technology]

FIG. 3 is a configuration diagram showing an example of a normal industrial robot. In the figure, 1 is the robot body, 2 is the vertical slide shaft that moves up and down by the drive of the robot body 1, 3 is the first arm, and 4 is the first arm 3.
A second arm 5 rotates around the tip of the second arm 4, a hand device 5 attached to the tip of the second arm 4 to grip a workpiece 6, and a workpiece table 7 on which the workpiece 6 is placed.

FIG. 4 is a configuration diagram of the hand device 5 in FIG. 3, where 5a is an actuator, 5b is a piston rod, and the left and right pistons 5c receive air pressure that acts on the center 5f or both ends 5g of the actuator 5a. A pair of piston rods 5b are driven to open and close hand arms 5b fixed to these piston rods 5b. Reference numeral 5e denotes a claw provided at the tip of each hand arm 5d.

In the conventional industrial robot hand device configured as described above, for example, when gripping and transporting the workpiece 6, first, both end chambers 5g in the actuator 5a are opened to the atmosphere by a command from a control unit (not shown). Then, when supply air pressure is applied to the central chamber 5t, the piston rods 5b move left and right to open the pair of claws 5e at their tips. In this state, the hand device 5 moves closer to the workpiece 6 according to the next command from the control section, and when it descends directly above the workpiece 6 and reaches the gripping position, the central chamber 5f of the actuator 5a is opened to the atmosphere. Then, supply air pressure is applied to both end chambers 5g, and the workpiece 6 is gripped by a pair of claws 5e and transported to a predetermined position according to a command from the control section.

[Problem that the invention seeks to solve]

In the conventional industrial robot hand device as described above, for example, when the hand device 5 approaches the workpiece 6 while descending, the hand device 5 may move toward the workpiece 6 due to a malfunction of the CPU or an erroneous operation by the operator. If it runs out of control in the direction and collides with the workpiece 6, workbench 7, etc., a reaction force of the impact will occur in the direction shown by the arrow in Fig. 4, damaging the hand device 5, second arm 4, etc., which do not have a buffer part. I had a problem like this.

This invention was made to solve this problem, and even if the tip of the hand device collides with a surrounding object, there is a risk of damage to the hand device etc. due to the buffer section provided within the hand device. The purpose of the present invention is to obtain a hand device for an industrial robot that is free of mechanical problems.

[Means for solving problems]

The hand device for an industrial robot according to the present invention includes: a pair of first hand arms that open and close in parallel in the horizontal direction by the operation of an actuator; and a pin connected to each of the pair of first hand arms. a pair of second hand arms that are rotatably attached and whose inner tip grip portions are moved in the horizontal direction by opening and closing the first hand arms; the tips of each of the second hand arms; Between the first hand arm and the second hand arm on the opposite side of the gripping portion sandwiching the pin, the second hand arm is prevented from rotating beyond a predetermined position due to gripping reaction force. a stopper for holding the second hand arm at the predetermined position; and a tension spring for holding the second hand arm at the predetermined position; It is configured by interposing a switch to do so.

[Effect]

As described above, the first hand arm and the second hand arm are pivotally connected by a pin, and a shock absorbing device is formed by a tension spring and a stopper interposed between both arms. Therefore, when the tip of the second hand arm receives an impact, the second hand arm rotates about the pin as a fulcrum to buffer the impact.

At the same time, the operating piece of the switch, which is normally pressed, is released and the robot suddenly stops.

〔Example〕

FIG. 1 is a block diagram of a hand device for an industrial robot according to an embodiment of the present invention, in which 4, 5a, 5
b and 5e are the same or equivalent parts as those with the same reference numerals in FIG. 4 showing the conventional example.

A pair of first hand arms 5d1 are fixed to the left and right piston rods 5b, respectively.
Similarly, 5d2 is a pair of second hand arms, which are pivotally connected to the first hand arm 5d1 by pins 5h. In addition, 5i is the first hand arm 5d.
A stopper provided on the first hand arm 5d1 side is normally used by the biasing force of the tension spring 5j stretched between the first hand arm 5d1 and the second hand arm 5d2. A fixed stopper 5i is connected to the second band arm 5d2.
It comes into contact with the protrusion provided on the side, and the second
The hand arms 5d2 are held so as to face each other symmetrically. Note that 5k is a normally open or normally closed contact switch such as a micro switch.
The actuating piece presses a protrusion 5l provided on the second hand arm 5d2 side.

In the industrial robot hand device according to the present invention configured as described above, the first hand arm 5d1 and the second hand arm 5d2 are normally controlled by increasing or decreasing the air pressure in the air chamber of the actuator 5a. move left and right as one, and the second hand arm 5d2 performs normal gripping or releasing work on the workpiece 6 with the left and right claws 5e by point restraint by the pin 5h and biasing force of the tension spring 5j. People are starting to do this.

Next, during the process in which the hand device 5 is transporting, gripping, etc. the workpiece 6, the hand device 5 collides with surrounding objects due to a malfunction of the CUP of the robot body 1 or an erroneous operation by the operator. In particular, the second arm 4 of the hand device 5
When the second hand arm 5d2 collides with a surrounding object, such as the workpiece 6 as shown in FIG. It rotates counterclockwise about the axis 5h against the force of the tension spring 5j. Therefore, the reaction force that the hand device 5 receives due to the impact is only the reaction force of the tension spring 5j that corresponds to the rotation angle of the second hand arm 5d2.
The impact applied to the hand device 5 due to the collision will be buffered.

Furthermore, due to the rotation of the second hand arm 5d2, the operating piece of the switch 5k separates from the protrusion 5l that was pressing it, so for example, if the switch 5k is a normally open contact, the contact is closed. The robot body 1 moves from the position to the open position, passes through a relay device, etc.
By transmitting an abnormality signal to the robot and suddenly stopping the robot, accidents subsequent to the above-mentioned collision are prevented.

〔Effect of the invention〕

As explained above, in this invention, the left and right arms of the hand device are divided into the first and second hand arms, respectively, these two arms are pivoted, and the holding force is normally applied by the biasing force of the tension spring. A pair of claws face each other and have a gripping function, and once the hand device collides with the surrounding object, the second hand arm rotates around the pin to which it is pivoted, and at the same time The operating piece of the switch, which is normally pressed, is released and switches the switch contacts to bring the robot to a sudden stop. This prevents damage caused by the impact of a collision, and also prevents accidents after this collision. This has the effect of providing a hand device for industrial robots that is free from fear.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a hand device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the hand device shown in FIG. 1, FIG. 3 is a block diagram showing an example of a normal industrial robot, and FIG. The figure is a configuration diagram showing an example of a conventional hand device. In the figure, 5 is a hand device, 5a is an actuator, 5d1 is a first hand arm, 5d2 is a second hand arm, 5h is a pin, 5i is a stopper, 5j is a tension spring, and 5k is a switch. In addition,
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A pair of first hand arms that open and close in parallel in the horizontal direction by the operation of an actuator, and each of the pair of first hand arms is rotatably attached via a pin. and a pair of second hand arms that move the inner tip gripping portions in the horizontal direction when the first hand arms are opened and closed, and each of the tip gripping portions of the second hand arms A stopper is provided between the first hand arm and the second hand arm on the opposite side of the pin to prevent the second hand arm from rotating beyond a predetermined position due to gripping reaction force. , a tension spring that holds the second hand arm at the predetermined position; and a switch that is activated when the second hand arm is rotated from the predetermined position by an external force against the biasing force of the tension spring. A hand device for an industrial robot, characterized in that it is equipped with a. 2. The hand device for an industrial robot according to claim 1, wherein the switch has a function of transmitting an abnormality signal to the robot body to stop the robot when the second hand arm collides.