JPS5850836B2 - Grip devices for industrial robots, etc. - Google Patents

Description

[Detailed Description of the Invention] This invention changes the grasping force of the opening/closing claw according to the weight of the article, and is capable of grasping even light and easily crushed articles without crushing them. This invention relates to a grip device.

Gripping devices are conventionally attached to industrial robots and used in a wide variety of applications, but when the weight of the object to be gripped is constant and known in advance, the gripping force of the opening/closing claws of these gripping devices is can be determined in advance according to the weight of

However, when it becomes necessary to grasp articles of different weights, it is necessary to adjust the grasping force, which requires labor and is troublesome.

The present invention has been made in view of the above-mentioned circumstances, and includes a gripping device for an industrial robot, etc., in which a plurality of article grasping sensors are arranged vertically on a grasping surface of an opening/closing claw thereof, and the article grasping portions of these sensors The gripping force of the opening/closing claws becomes stronger as the number of the opening/closing claws decreases, so that the gripping force of the opening/closing claws can be automatically changed according to the weight of the article. Focusing on the fact that many objects are fragile and heavy objects are strong, the object is to allow even objects that are easily crushed to be grasped without any trouble.

Embodiments of the present invention will be described in detail below based on the drawings.

First, the embodiments shown in FIGS. 1 to 5 will be described in detail. 1...
...This is the main body of the grip device, and shows the tip of the arm of an industrial robot, etc.

2.2...This is an opening/closing pawl that is pivoted at 3°3 to the main body 1 so that it can be opened and closed on a horizontal plane, and is engaged by a sector gear.

In this embodiment, the claws 2, 2 are configured to be able to grasp the article W in the closed position.

4...This is a cylinder device (in the embodiment, a single acting cylinder device with a built-in compression spring 4a) which is connected between the claws 2, 2.

In the fluid non-operating state, the cylinder device 4 has a spring 4
a so that it is in the extended position, that is, the claws 2, 2 are in the closed position.

S: In this embodiment, a plurality of sensors (three in this embodiment) for grasping the article W are arranged vertically on the inner grasping surfaces of the claws 2, 2.

Note that the example sensor S includes light emitters (light sources) S□ to S3,
Photoreceptor (phototransistor in this example) S1o-S
This is due to the combination with 30.

6...A control valve that controls the pressure of the fluid (air in the embodiment) actuated in the cylinder device 4 based on the output from the sensor S.

The control valve 6 is a proportional electromagnetic IJ-F valve in this embodiment.

6a is the solenoid.

7...It is a compressor.

The cylinder device 4, relief valve 6, and compressor I are then piped as shown in FIG.

E...IJ by the output from sensor S
- Control means for controlling the valves 6-8.

X1 to X3 are relays, and X1o to X3o are relays
1 to X3 are normally open contacts, and R1 to R3 are resistors.

SW...Switch.

R4...Resistor.

Then, the light sources 81 to S3 and the phototransistor 510-8
30, relays X1 to X3, contacts X1o to X3o, resistors R□ to R3, solenoid 6a, switch SW, and resistor R4 are connected as shown in FIG. 2 to form an electric circuit.

Further, the operation of this embodiment will be explained.

First, power is applied to the electric circuit in the state shown in Figure 2,
Drive the compressor 7.

Then, the phototransistors SIO"""S30 receive light from the light sources 81 to S3 and all operate, and all the relays X
1 to X3 are energized and their contacts X1o to X3o are closed, but the switch SW is open, so the solenoid 6a
No current flows through.

Therefore, the air pressure by the compressor 7 is IJ IJ-
Since the fluid resistance at the valve 6 is maximum, all of the fluid acts on the cylinder device 4, and the cylinder device 4 contracts against the force of the spring 4a, and the claws 2.2 are in an open state.

Then, move the main body 1 and place the claws 2, 2 around the article W placed on a table (not shown), for example.
position.

Then, the phototransistor SIO""'S30 becomes inactive due to the presence of the article W between the claws 2, 2, all the relays X1 to X3 become de-energized, and the contacts X1o to X3o become open, and The switch SW is closed by an output signal from a control device (not shown).

Therefore, at this time, the only resistance in the circuit including the solenoid 6a is the resistor R4, the fluid resistance at the IJ-F valve 6 becomes slightly smaller, and the air pressure applied to the cylinder device 4 is slightly increased.

Therefore, the cylinder device is slightly expanded by the force of the spring 4a,
The claw 2.2 grasps the article W with a weak force.

Then, slowly raise the main body 1, that is, the claws 2,
2 (upwards in Figures 2-5).

At this time, if the gripping force of the claws 2, 2 is smaller than the force required to lift the article W, slipping occurs between the article W and the claws 2, 2, and only the claws 2, 2 rise while the article W remains as it is. This will result in

Then, as shown in FIG. 3, a space is created between the light source S1 and the phototransistor 810, and the phototransistor St
Since only O is activated, relay X1 is energized,
The contact X1o is closed, and the resistance of the circuit including the solenoid 6a becomes parallel to resistors R4 and R1.

Since the current at this time is slightly larger than the current when only the resistor R4 was used last time, the fluid resistance in the relief valve 6 is further reduced, and the air pressure applied to the cylinder device 4 is further reduced than before.

Therefore, the cylinder device 4 is expanded by the force of the spring 4a, and a larger force than the previous time is applied, and the claws 2, 2 grasp the article W with a stronger force than the previous time.

Even so, if the gripping force is smaller than the force required to lift the article W, only the claws 2, 2 will rise as described above.

Then, as shown in Fig. 4, there will be a space between the light source S0°S2 and the phototransistor sto9S20,
Since phototransistor SIOt 820 is activated, relay X1. X2 is energized, and the contacts X1o,
X2o is closed, and the resistance of the circuit including the solenoid 6a is the parallel resistance of resistors R4, R1, and R2.

Since the current at this time is larger than the current in the previous case where the resistor R4 and the R work were connected in parallel, the fluid resistance in the relief valve 6 is further reduced, and the air pressure applied to the cylinder device 4 is further reduced.

Therefore, the cylinder device 4 is expanded by the force of the spring 4a, and a larger force than the previous time is applied, and the claws 2, 2 grasp the article W with an even stronger force than the previous time.

Even so, if the gripping force is smaller than the force required to lift the article W, only the claws 2, 2 will rise as described above.

Then, as shown in FIG. 5, there will be a space between all the light sources S1 to S8 and all the phototransistors S1o to S30,
Since all phototransistors SIO""'830 are activated, all relays X1 to X3 are energized and their contacts X
1o to X3o are closed, and the resistance of the circuit including the solenoid 6a becomes parallel to resistors R4, Ro, R2, and R3.

The current at this time is higher than the previous case of parallel resistors R4, R1, and R2 (maximum in this example), so
+71. ) - The fluid resistance at the valve 6 is further reduced (minimum in this embodiment) and the air pressure on the cylinder arrangement 4 is further reduced (minimum in this embodiment).

As a result, the cylinder device 4 is extended in the direction of expansion by the force of the spring 4a, and a larger force than the previous time (the maximum in this embodiment) is applied, so that the claws 2, 2 grasp the article W with the maximum force.

After all, the fewer the number of article gripping parts of the sensor S, the stronger the gripping force of the claws 2, 2 becomes.

In other words, the lighter the article W, the weaker the claws 2, 2 can grasp it,
The heavier the article W, the stronger the claws 2, 2 can grasp it.

Note that when the article W is to be separated from the claws 2, 2, the switch SW is opened by an output signal from the control device (not shown), no current flows through the solenoid 6a, and IJ IJ-
The air pressure resistance at the valve 6 becomes maximum, and the maximum air pressure is applied to the cylinder device 4 against the force of the spring 4a.
The cylinder device 4 is retracted, the claws 2, 2 are opened, and the article W can be separated from the claws 2, 2.

Next, the embodiment shown in FIG. 6 will be described.

In this embodiment, the cylinder device is a single-acting cylinder device,
The article grasping sensor uses back pressure from air blowing to grasp the article W.
can be detected, and the control valve is a proportional solenoid pressure reducing valve.

Differences from the previous embodiment will be explained below.

20.20...Opening/closing claw.

SO...It is an article grasping sensor.

SOa to SOc are air blowing holes provided in three locations in the vertical direction on one claw 20.

SO1 to SO3 are bellows.

SO1□ to SO are throttle valves. SO2, ~5O23
are normally open contacts connected to bellows SO1-SO3.

These are connected and piped as shown in Figure 6, and the sensor SO
is configured.

40 is a single-acting cylinder device, and in the fluid non-operating state, it is set in a retracted position by a compression spring 40a, that is, the pawls 20, 20 are in an open position.

60...Proportional electromagnetic pressure reducing valve.

60a is a solenoid of the pressure reducing valve 60.

8...It is an electromagnetic switching valve.

8a is a solenoid of the switching valve 8.

SWO......Switch.

Then, the sensor SO, compressor 7, cylinder device 40, pressure reducing valve 60, and switching valve 8 are arranged as shown in FIG. Connected like.

In this embodiment, the switch SW and the resistor R4 in the embodiments shown in FIGS. 1 to 5 are omitted.

The rest is the same as the previous embodiment.

Furthermore, the operation of this embodiment will be briefly explained.

First, in the state shown in Fig. 6, the compressor 1 is driven and the air is passed through the throttle SOl, ~SO, and into the pore 5Oa=
Air is blown from the SOc, and the eye-like claws 20.20 are positioned around the article W.

Then, the switch SWO is closed by an output signal from a control device (not shown), voltage is applied to the solenoid 8a, the switching valve 8 is switched to the right in the figure, and the air from the compressor 7 is also forced into the cylinder device 40.

However, at this time, the air blown out from the pores SOa to SOc is resisted by the presence of the article W, so that the entire bellows SO0 to
Back pressure is applied to SO3, its contacts SO2, ~5023 are closed, and all relays X1~X3 are accordingly energized, their contacts X1°~X3o are closed, and the resistors R0 and R2 of the circuit including the solenoid 60a are energized. Since it is connected in parallel with R3 and the maximum current flows, most of the air forced into the cylinder device 40 escapes from the pressure reducing valve 60.

Therefore, the cylinder device 40 is slightly expanded against the force of the spring 40a, and the claws 20, 20 grasp the article W with a weak force.

Then slowly raise the main body 1 (set the claws 20 and 20 to the 6th
(upwards in the figure).

At this time, if the grasping force of the claws 20.20 is smaller than the force required to lift the article W, the article W remains in the same position and the claws 20.
Only 0.20 will increase.

Then, the following is the same as in the embodiment shown in FIGS. 1 to 5 above.
At first, the back pressure of bellow SO1 disappears and its contact SO2,
becomes open.

Furthermore, the back pressure on the bellow SO2 disappears and the contact SO2
2□ is also open.

Furthermore, the back pressure of the bellow SO3 disappears, and its contact 5O23 also becomes open.

And so on, relay X1, and then Xl and X2
Further, all the relays X1 to X3 are sequentially deenergized, and the contact X1o, furthermore, X1o and X2o, and furthermore, all the contacts X1o to X3o are sequentially brought into the state.

Therefore, the current flowing through the variable solenoid 60a becomes smaller (zero at the end), the air escaping from the pressure reducing valve 60 becomes smaller (zero at the end), and the cylinder device 40
In the direction of stretching by force 0a, and successively larger forces (
Finally, the maximum force) acts, and the claws 2020 grasp the article W with a sequentially strong force.

In the end, the fewer the number of object grasping parts of the sensor SO, the more
The gripping force of the claws 20.20 becomes stronger.

In other words, the lighter the article W is, the weaker the force is required by the claws 20.20 to grasp it, and the heavier the article W is, the stronger the force is required to grasp it.

Note that when the article W is to be separated from the claws 20, 20, the switch SWO is opened by an output signal from the control device (not shown), and the switching valve 8 is switched to the left in the figure.

Therefore, the pressurized air in the cylinder device 40 is released to the outside by the force of the spring 40a, the cylinder device 40 is contracted, the claws 20, 20 are opened, and the article W can be separated from the claws 20, 20.

Next, the embodiment shown in FIG. 7 will be described. In this embodiment, the cylinder device is replaced with the single acting cylinder device 4 and m- in the embodiment shown in FIGS. This shows piping in which a throttle valve 9 is added between the servo valve 61 and the servo valve 61.

If this piping configuration is replaced with the piping configuration of the embodiment shown in FIGS. 1 to 5 or 6, the operation can be explained in the same manner as in those embodiments, so the explanation thereof will be omitted.

Next, the embodiment shown in FIG. 8 will be described. In this embodiment, the cylinder device is a double-acting cylinder device 41, and the control valves are the first to
IJ in the embodiment of Fig. 5 IJ-F valve 6 and gate,
1 shows piping to which an electromagnetic two-position switching valve 10 is added.

If this piping configuration is replaced with the piping configuration of the embodiment shown in FIGS. 1 to 5 or 6, the operation can be explained in the same manner as in those embodiments, so the explanation thereof will be omitted.

Next, the embodiment shown in FIG. 9 will be described. In this embodiment, the cylinder device is replaced with the double-acting cylinder device 4 in the embodiment shown in FIG.
1 and m-, the control valves are the pressure reducing valve 60 in the embodiment shown in FIG.

If this piping configuration is replaced with the piping configuration of the embodiment shown in FIGS. 1 to 5 or 6, the operation can be explained in the same manner as in those embodiments, so the explanation thereof will be omitted.

Finally, the embodiment shown in FIG. 10 will be described. In this embodiment, the cylinder device is the same as the double-acting cylinder device 41 in the embodiments shown in FIGS. 8 and 9, and the control valve is the same as that in the embodiment shown in FIG. 7 shows piping in which a throttle valve identical to the throttle valve 9 in the embodiment of FIG. 7 is added between the cylinder device 41 and the servo valve 61.

If this piping configuration is replaced with the piping configuration of the embodiment shown in FIGS. 1 to 5 or 6, the operation can be explained in the same manner as in those embodiments, so the explanation thereof will be omitted.

In addition to the above-mentioned embodiments, it is also possible to use a sensor capable of detecting an article using negative pressure caused by suction of air as the article grasping sensor.

In this case, for example, in the embodiment of FIG.
2□ to 5O23 should be normally open contacts that are closed by negative pressure, and the piping of the sensor SO may be connected so as to suck air from the pore 5Oa=SOc.

Further, as an article grasping sensor, for example, in the embodiment shown in FIG. 6, pores SOa to SOc are provided in both claws 20, 20, and from one pore 5Oa=SOc to the other S Oa=S
It is also possible to uniformly carry out the method by blowing air toward Oc, using this blowing air pressure to operate the bellows SO1 to SO3, and using a sensor capable of detecting the article.

Note that the above explanations are for cases in which the claws close when the cylinder device is extended, and open when the cylinder device contracts, but even in the opposite case, it can be easily done by changing the piping. It is possible to implement.

In addition, when the article is hollow and the hollow part of the article is to be grasped by opening the claw, the sensor S using the combination of the light sources 81 to S3 and the phototransistors StO to 830 cannot be used. It can be implemented uniformly.

Since this invention is as explained above, it is possible to automatically change the gripping force of the opening/closing claw according to the weight of the article. It is possible to grasp the weight of the item without losing weight, and unlike conventional methods, it is possible to grasp the
There is no need to adjust your grip strength.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a plan view of the grip device, FIG. 2 is an overall explanatory view, and FIGS. 3 to 5 are action explanatory views. FIG. 6 is an overall explanatory diagram showing another embodiment, and FIGS. 7 to 10 are all explanatory diagrams showing main piping parts of the different embodiments. In the figure, 2, 2, 20, 20... are all opening/closing claws, 4, 40, 41... are all cylinder devices, and 6, 60, 61... are all Proportional control valve, 10...Solenoid 2-position switching valve, S, SO...
. . . All of them are an article grasping sensor, E: a control unit, and W: an article.

Claims (1)

[Scope of Claims] 1. A gripping device for an industrial robot, etc., comprising a cylinder device connected to open and close the opening/closing claw, a plurality of article grasping sensors arranged vertically on the grasping surface of the opening/closing claw, and these sensors. A control valve that controls the pressure of fluid applied to the cylinder device based on the output from the sensor, and a control means that controls the control valve based on the output from the sensor, and the control means is configured to control the object gripping of the sensor. A grip device for the industrial robot, etc., configured such that the gripping force of the opening/closing claw becomes stronger as the number of parts decreases. 2. A gripping device for an industrial robot or the like according to claim 1, wherein the control valve is a proportional electromagnetic IJ-F valve. 3. A grip device for an industrial robot or the like according to claim 1, wherein the control valve is a proportional electromagnetic pressure reducing valve. 4. A grip device for an industrial robot or the like according to claim 1, wherein the control valve is a servo valve. 5. A grip device for an industrial robot or the like according to claim 1.2.3 or 4, wherein the cylinder device is a single-acting cylinder device. 6 The cylinder device is a double-acting cylinder device, and an electromagnetic type 2
A gripping device for an industrial robot or the like according to claim 1, 2 or 3, further comprising piping with a position switching valve. 7. A grip device for an industrial robot or the like according to claim 1 or 4, wherein the cylinder device is a double-acting cylinder device. 8. A gripping device for an industrial robot or the like according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the article grasping sensor is a combination of a light emitting body and a light receiving body. 9. A gripping device for an industrial robot or the like according to claim 1, 2, 3, 4, 5.6 or 7, wherein the article grasping sensor is capable of detecting back pressure due to air blowing. 10 The article grasping sensor is capable of detecting the blowing pressure of air blowing out.
A gripping device for an industrial robot or the like according to item 5, 6 or 7. 11. A gripping device for an industrial robot or the like according to claim 1, 2, 3, 4, 5.6 or 7, wherein the article grasping sensor is capable of detecting negative pressure due to air suction.