JPH05305593A - Article nipping device - Google Patents

Abstract

PURPOSE:To provide an article nipping device capable of easily providing a highly precise article nipping force by use of compressed air relatively easily available in a factory at a low manufacturing cost. CONSTITUTION:An article nipping device has an electromagnetic switching valve 15 connected to one-side working chambers 9, 10 of air cylinders 1, 2 for driving claws 7, 8 for nipping an article 6 to supply compressed air or stop the supply; an electromagnetic switching valve 16 for exhausting the compressed air in the one-side working chambers to the outside or stopping the exhaust; and a pressure control valve 24 connected to the other working chambers 12, 13 to decreasingly control the pressure to a fixed pressure. According to the operation signal from an electric control means 29 which outputs the signal according to the difference between a detected pressure and a set value, the two electromagnetic switching valves 15, 16 are operated to increasingly control the pressures of the one-side working chambers, whereby the air pressure cylinders 1, 2 allow the claws 7, 8 to satisfactorily nip the article without breaking it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an article holding device suitable for use in an arm portion of a robot or the like which holds and conveys a fragile article.

[0002]

2. Description of the Related Art Conventionally, an article holding device provided on an arm portion of a robot or the like for holding a fragile article such as a core of a casting or a resin product with a nail and carrying the article is stronger than a predetermined value. If the gripping force is weaker than the specified value, the product may not be able to be held, or may be dropped and damaged due to operational vibration during transportation. .. For this reason, an electric servomotor that can obtain a holding force of a predetermined value with high accuracy is used to drive the claw that holds the article.

[0003]

However, the use of such an electric servomotor allows the claws for holding an article to be driven with high precision and speed, but on the other hand, the product structure is complicated and the price is high, so maintenance is difficult. However, there is a problem that it is troublesome and increases the manufacturing cost of the device.

The present invention is intended to solve such a problem, and provides an article holding device which uses compressed air relatively easily available in a factory and can obtain a high-precision holding force at low cost. With the goal.

[0005]

Therefore, according to the present invention, a movable portion is provided with a pneumatic cylinder for driving a claw for holding an article,
This pneumatic cylinder is connected to one working chamber to supply and stop compressed air to one working chamber, and an electromagnetic on-off valve that discharges compressed air in one working chamber to the low pressure side and discharges it. An electromagnetic on-off valve for stopping is provided, and a pressure control valve is connected to the other working chamber of the pneumatic cylinder to supply compressed air to the other working chamber to control its pressure to a constant pressure. The on-off valve is capable of raising and lowering the pressure in one working chamber of the pneumatic cylinder, and is electrically connected to an electric control means that detects the pressure in one working chamber and outputs an operation signal according to the difference between the detected pressure and the set value. It is characterized by being provided by. In order to solve the same problem, it is preferable that a part of the compressed air supplied to the other working chamber of the pneumatic cylinder is throttled and discharged to the low pressure side.

[0006]

In the structure of the present invention, the pressure in one working chamber of the pneumatic cylinder is raised and lowered by the operation of supplying and discharging the compressed air by the operation of the two electromagnetic on-off valves, and is controlled to the set value of the electric control means. The pressure cylinder rapidly drives the claw that holds the article by the difference in the acting force between the pressure in the one working chamber and the pressure in the other working chamber controlled to a constant pressure by the pressure control valve. Since the electric control means detects the pressure of the one working chamber and operates the two electromagnetic on-off valves according to the difference from the set value, the pressure control of the one working chamber can be performed to the set value with high accuracy. Since a highly versatile pneumatic valve is used with the compressed air that can be obtained and easily obtained in the factory as a power source, it is possible to satisfactorily obtain a highly accurate holding force at low cost. Further, by squeezing and discharging a part of the compressed air supplied to the other working chamber of the pneumatic cylinder to the low pressure side so as to have the pressure control valve in the operating state, the response performance of the valve is improved and the other working chamber The pressure can be satisfactorily maintained at a constant pressure, and the gripping force of the article can be obtained with higher accuracy.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numerals 1 and 2 are pneumatic cylinders, which are fixedly provided on a movable portion 3 of an actuator, and are provided with claws 7 and 8 for holding an article 6 by a piston rod 4 and 5 so as to be driven. The two pneumatic cylinders 1 and 2 are provided by connecting one working chamber 9 and 10 on the head side by a flow passage 11 and the other working chamber 12 and 13 on the rod side by a flow passage 14, respectively. ing. Reference numerals 15 and 16 denote solenoid on-off valves,
The electromagnetic on-off valve 15 is installed in the flow path 18 that connects the flow path 11 and the pneumatic pressure source 17 side, and supplies compressed air from the pneumatic pressure source 17 to the one working chamber 9 or 10 and supplies the compressed air. The electromagnetic on-off valve 16 is installed in the flow passage 19 which is branched from the flow passage 11 and is open to the outside air on the low pressure side so that the compressed air in the working chambers 9 and 10 can be stopped. It is provided so that it can be discharged to the outside air or stopped.
The electromagnetic on-off valves 15 and 16 are the resting springs 20,
It is normally closed by the force of 21. (Note that the two electromagnetic opening / closing valves may be integrally provided so as to share the valve body in order to miniaturize the valves.)

Reference numerals 22 and 23 are flow rate adjusting valves with a check valve.
A valve 22 installed in the flow path 18 controls the flow rate of the compressed air flowing to the electromagnetic opening / closing valve 15, and a valve 23 installed in the flow path 19 controls the flow rate of the compressed air flowing through the electromagnetic opening / closing valve 16 to the outside air. The opposite direction is provided for free flow. A pressure control valve 24 is installed in a flow path 25 connecting the flow path 14 and the air pressure source 17 side, and when the pressure on the flow path 14 side rises to a set value of the spring 26 force, the flow path 25 Is provided so that the pressure in the working chambers 12, 13 can be maintained at a constant pressure. Reference numeral 27 denotes a throttle, which is installed in a flow path 28 which is branched from the outlet side flow path 25 of the pressure control valve 24 and opened to the outside air, and on the other hand, a part of the compressed air in the working chambers 12 and 13 is always throttled to the outside air. The pressure control valve 24 is provided so as to be discharged and to be activated.

Reference numeral 29 is an electric control means having a pressure setting mechanism (not shown) for controlling the operation of the electromagnetic on-off valves 15 and 16.
Electromagnet 3 of solenoid on-off valves 15 and 16 via electric wires 33 and 34
1 and 32, the pressure on the flow path 11 side is detected by the pressure sensor 30, and the solenoid on-off valve is operated according to the difference between the detected pressure and the set value set by the operation of the built-in pressure setting mechanism. It is provided to output an actuation signal for actuating 15, 16.

Next, the operation of this structure will be described. FIG. 1 shows that the two solenoid on-off valves 15 and 16 are in a rest state and flow paths 18 and 1
9 is closed, compressed air from the air pressure source 17 flows from the flow passage 25 through the pressure control valve 24 and the flow passage 14, and is supplied to the other working chambers 12, 13 of the pneumatic cylinders 1, 2.
On the other hand, the pressure inside the working chambers 12 and 13 is maintained at the set pressure of the pressure control valve 24. And the pneumatic cylinders 1, 2
Drives nails 7 and 8 to a position away from article 6.

From this state, when the electric control means 29 is operated to hold the article 6 and the electromagnetic opening / closing valve 15 is operated, the compressed air from the air pressure source 17 flows from the flow path 18 to the flow path 11
Is supplied to the one working chamber 9, 10 of the pneumatic cylinders 1, 2 and the pneumatic cylinders 1, 2 drive the pawls 7, 8 to hold the article 3. When the pressure in the working chambers 9 and 10 rises to the set value of the electric control valve 29, the solenoid opening / closing valve 15
Are actuated to close the flow path 18 and the pneumatic cylinders 1, 2
Will stop. At this time, if the pressure in the one working chamber 9, 10 rises above the set value due to some cause, the electric control means 29 detects the phenomenon via the pressure sensor 30 and operates the electromagnetic opening / closing valve 16. Solenoid on-off valve 16
Discharges the compressed air due to the pressure increase above the set value to the outside air, and corrects the pressure in the working chambers 9 and 10 to the set value and stops the discharge. Such an electromagnetic opening / closing valve 15, 1
By the operation of 6, the claws 7 and 8 hold the article 6 in a good condition, and the article 6 is reliably transported to a predetermined place by the movement of the movable portion 3 without being broken.

In order to release the holding of the article 6, the electromagnetic on-off valve 16 is operated to discharge the compressed air in the one working chamber 9, 10 to the outside air, so that the pneumatic cylinders 1, 2 are operated in the other working chamber. The pawls 7 and 8 are actuated by the pressure of 12 and 13 so that the pawls 7 and 8 are quickly separated from the article 6.

In this operation, two solenoid on-off valves 1
Since the pressures in the first working chambers 9 and 10 of the pneumatic cylinders 1 and 2 are controlled up and down by the action of supplying and discharging the compressed air by the operations of 5 and 16, the flow path 11 via the pressure sensor 30 of the electric control means 29. That is, in combination with the pressure detection action in the one working chambers 9 and 10, the pressures in the one working chambers 9 and 10 are controlled to a set value with high precision and speed, and a highly versatile pneumatic valve using compressed air as a power source. I'm trying to use it,
The manufacturing cost can be reduced, and the high precision article holding force can be satisfactorily obtained.

The other working chamber 1 of the pneumatic cylinders 1 and 2
Since a part of the compressed air supplied to the Nos. 2 and 13 is squeezed and discharged to the outside air by the squeeze 27, the pressure control valve 24 is always in the operating state and its response performance is enhanced, and the other working chamber 1
The pressure of 2 and 13 can be satisfactorily maintained at a constant reduced pressure.
The holding power of is obtained with higher accuracy. Furthermore, because of the combination of the pneumatic valves, the structure thereof is simple and the handling and maintenance management can be performed easily compared with the conventional use of the electric servomotor.

FIG. 2 shows another embodiment of the present invention. The same parts as those of the first embodiment are designated by the same reference numerals and different points will be described. 35 is the other working chamber 12, 13 of the pneumatic cylinders 1, 2.
Is a pressure control valve for maintaining a constant reduced pressure of the spring 36.
When the pressure rises to a set value, the flow passage 25 is closed, and when the pressure rises above the set value for some reason, compressed air resulting from the pressure rise is discharged to the outside air and the other working chambers 12, 13 It has a relief pressure reducing valve provided so as to maintain the pressure reduced to a constant pressure. Then, the two electromagnetic opening / closing valves 15 by the electric control means 29,
When the pressure in the one working chamber 9 and 10 is controlled to rise and fall by the operation of 16, the pneumatic cylinders 1 and 2 hold the article 6 by driving the pawls 7 and 8 by the acting force due to the pressure difference between the two working chambers. Or remove it from the article 6.

FIG. 3 shows an example of a specific structure of the pressure control valve 35. The pressure reducing valve body 37 is separated from the valve seat 39 by the force of the spring 36 via the rod member 38 and flows into the primary side port 40. Compressed air flows through the opening of the valve seat 39 to the secondary side opening 41 and is supplied to the other working chambers 12 and 13. Secondary side port 41
A part of the compressed air that has flowed through flows through the small holes 42 and acts on the diaphragm 43. On the other hand, when the force acting on the diaphragm 43 becomes larger than the force of the spring 36 due to the pressure increase in the working chambers 12 and 13, the diaphragm 43 is moved to the left in the drawing and the pressure reducing valve body 37 is seated on the valve seat 39 to shut off the flow. ..
The pressure on the side of the secondary port 41 causes the spring 3
When the force is increased to 6 force or more, the diaphragm 43 is further moved to the left in the drawing, the relief valve hole 44 is opened apart from the rod member 38, and the compressed air resulting from the pressure increase of the set value or more is provided to the outside air. ing.

In this structure, the relief mechanism provided in the pressure control valve 35 discharges part of the compressed air in the other working chamber 12, 13 to the outside air, so that the pressure control valve 35 is always in the operating state. , The other working chambers 12, 13 and the secondary side port 4 of the pressure control valve 35 due to the operation of the pneumatic cylinders 1, 2.
Even if a pressure fluctuation occurs in the compressed air between 1, the pressure fluctuations are quickly eliminated by the operation of the pressure reducing valve body 37 and the diaphragm 43, while the pressures in the working chambers 12 and 13 are satisfactorily maintained at a constant pressure. It is possible to obtain the same effect as that of the embodiment.

[0018]

As described above, according to the present invention, the movable portion is provided with the pneumatic cylinder for driving the claw that holds the article, and the pneumatic cylinder is connected to one working chamber to supply the compressed air to the one working chamber. And an electromagnetic on-off valve that shuts off the supply of the compressed air and a solenoid on-off valve that discharges compressed air in one working chamber to the low pressure side and stops its discharge, and is connected to the other working chamber of the pneumatic cylinder. By providing compressed air to the other working chamber and controlling its pressure to a constant pressure, two electromagnetic on-off valves enable the pressure of one working chamber of the pneumatic cylinder to be controlled up and down. Since it is provided by being electrically connected to an electric control means that detects the pressure of the device and outputs an operation signal according to the difference between the detected pressure and the set value, a general-purpose pneumatic valve can be used to hold the device at low cost and with high accuracy. It is possible to provide a device with good strength. , Yet its structure a combination of pneumatic valve also becomes simpler, the use and Hirabe handling and maintenance of the conventional electric servo motor can be easily performed.

Further, since a part of the compressed air supplied to the other working chamber of the pneumatic cylinder is provided so as to be squeezed and discharged to the low pressure side, the pressure control valve for controlling the pressure of the other working chamber to a constant pressure is operated. In addition, since the response performance is improved, the pressure in the other working chamber can be satisfactorily maintained at a constant pressure even when it is installed in a device with frequent operation, and the gripping force of the article can be obtained with higher accuracy.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an article holding device showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of an example of a pressure control valve.

[Explanation of symbols]

 1, 2 Pneumatic cylinder 3 Movable part 6 Article 7, 8 Claw 9, 10 One working chamber 12, 13 Other working chamber 15, 16 Electromagnetic on-off valve 17 Pneumatic source 24 Pressure control valve 27 Throttle 29 Electric control means 30 Pressure sensor 35 relief pressure reducing valve

Claims (3)

[Claims] 1. A pneumatic cylinder for driving a claw that holds an article is provided in a movable portion, and the pneumatic cylinder is connected to one working chamber to supply compressed air to the one working chamber or to stop the supply thereof. And an electromagnetic on-off valve that discharges the compressed air in the one working chamber to the low pressure side and stops the discharge, and connects it to the other working chamber of the pneumatic cylinder to apply the compressed air to the other working side. A pressure control valve that supplies the pressure to the chamber and controls the pressure to a constant pressure is provided, and the two electromagnetic on-off valves enable the pressure of one working chamber of the pneumatic cylinder to be controlled up and down. An article holding device which is electrically connected to an electric control means for outputting an operation signal according to a difference between a pressure and a set value. 2. The article holding device according to claim 1, wherein a part of the compressed air supplied to the other working chamber of the pneumatic cylinder is always discharged to a low pressure side through a throttle. 3. A relief pressure reducing valve is provided as a pressure control valve connected to the other working chamber of the pneumatic cylinder, and a part of compressed air supplied to the other working chamber is discharged to a low pressure side by a relief mechanism of the pressure reducing valve. It is provided, The claim 1 characterized by the above-mentioned.
The article holding device described in 1.