JPS6338941Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit for detecting malfunction of a paint gun that automatically paints an automobile body.

An example of an automatic coating machine for automatically painting automobile bodies is shown in Fig. 1. A workpiece W is placed on a dolly 2 attached to a conveyor 1, and the workpiece W is placed on a dolly 2 attached to a conveyor 1. It will be moved in the direction shown. A gate-shaped coating machine main body 5 is installed across the conveyor 1, and has left and right columns 3 and a lifting girder 4 attached to these columns 3 so as to be movable up and down. Painting on work W is done with work W.
While the paint passes through the coating machine main body 5 due to the movement of the conveyor 1, paint from the coating gun 6 attached to the elevating girder 4 is applied to the workpiece W automatically.

The coating machine main body 5 shown in FIG. 1 is for painting the upper surface of an automobile body, and includes a hood part W1,
The roof portion W2 and trunk portion W3 are painted. The painting gun 6 paints the upper surface of the automobile body while reciprocating in the left-right direction (in the direction perpendicular to the drawing in FIG. 1), and in order to maintain the distance between the work W and the painting gun almost constant. Paint gun 6
It is necessary to move it up and down.

Workpiece W and painting gun 6 as workpiece W moves forward
The locus of relative movement in the vertical direction with respect to the above is shown by the broken line in FIG. In the figure, the coating machine main body 5 in the state shown by the imaginary line temporarily suspends coating after the coating gun 6 coats the hood W1 up to the coating end position B due to the forward movement of the workpiece W. The relative positions of the workpiece W and the sprayer main body 5 are shown when the workpiece W and the sprayer main body 5 have moved up and reached the coating restart position C.

The movement of the coating gun 6 and the start and end of coating are controlled using a pulse transmitter, a counter, etc., although not shown. In other words, work W
A limit switch (not shown) detects that A has approached the sprayer main body 5 by a predetermined distance, and a signal from the limit switch operates a pulse transmitter, a counter, etc.
Painting starts at position B, painting is interrupted at position B and the painting gun 6 is raised, painting is restarted at position C, painting is interrupted at position D, the painting gun 6 is lowered, and painting is restarted at position E.

After the painting gun 6 finishes painting the hood part W1,
After reaching the position, the coating gun 6 moves upward to the C position, but if this is not done, the coating gun 6 will collide with the workpiece W as shown by G in FIG. Therefore, in order to detect such malfunction of the paint gun 6 and stop the conveyor 1 or issue a warning to the operator, a paint gun malfunction detection circuit 11 as shown in FIG. 2 has been conventionally used. .

This detection circuit 11 is provided with a delay circuit 14 having a timer 13 connected to a switch 12 which is activated when the paint gun 6 is in the B position. This switch 12 is activated in response to a rising command signal when the coating gun 6 reaches the B position by the pulse counter, and the timer 13 operates during the time during which the coating gun 6 moves from the B position to the C position. It has a built-in relay that activates the normally open contact 13a after a corresponding period of time has elapsed. A limit switch LS is attached to the sprayer body 5 to detect when the coating gun 6 has risen to the upper limit position, and a higher limit detection circuit 1 includes a relay 15 that is activated when the limit switch LS is closed.
6 is provided in the detection circuit 11. Further, a normally closed contact 15a, which is turned off by the operation of the relay 15, the normally open contact 13a, and these contacts 13a, 15a.
A discriminator circuit 18 is provided having a relay 17 which is activated when both are closed. It also has a self-holding normally open contact 17a that is turned on by the operation of the relay 17 and a normally closed contact 19 for reset,
An alarm circuit 20 having an alarm lamp R and an alarm buzzer B is provided. Note that a circuit (not shown) is connected to the normally open contact 17a for stopping the conveyor 1 when the contact 17a is turned on.

Therefore, after the painting gun 6 is in position B,
When it rises to position C, the limit switch usually
Since LS is activated and relay 15 is activated, normally closed contact 15a is turned off, no current flows through relay 17, and alarm lamp R and alarm buzzer B are not activated. However, if the limit switch LS does not turn on even though a certain period of time set by the timer 13 has elapsed after the paint gun has not fully risen and the switch 12 is activated, the switch 15 will not turn on.
a remains on and the contact 13a is turned on, so the relay 17 is activated and the contact 17a is turned on, the alarm lamp R lights up, and furthermore, the alarm buzzer B sounds and the conveyor 1 is stopped. Ru.

However, with such a conventional paint gun malfunction detection circuit 11, although it is possible to detect a delay in the upward movement of the paint gun 6, it is difficult to detect the position of the paint gun such as a limit switch LS. If the equipment is defective, the discrimination circuit 18 will not operate, causing the problem that the coating gun 6 may collide with the workpiece W.

The present invention is equipped with a circuit that determines whether the painting gun is painting a specific part of the work such as the hood or trunk lid of the work, and a rise limit detection circuit that detects when the paint gun has moved to the workpiece's rise limit position. This will issue an alarm if the limit switch that accidentally detects the upper limit position is activated for some reason while the paint gun is painting a hood, etc.
The purpose is to solve the above problem by making it possible to take measures such as immediately stopping the machine.

Next, a malfunction detection circuit for a coating gun according to an embodiment of the present invention shown in FIG. 3 will be explained.
In FIG. 3, parts common to those shown in FIG. 2 are given the same reference numerals.

As shown in the figure, the malfunction detection circuit 11 is provided with a rise limit detection circuit 16 having a limit switch LS and a relay 15 that are activated when the coating gun 6 rises to the rise limit position, as in the prior art. Further, when the painting gun 6 is painting the hood part W1, which is one of the specific parts of the workpiece, a switch 21 is turned on by a signal indicating that this is being painted, and this switch 21 is turned on. A hood painting detection circuit 23 consisting of a relay 22 that operates when the paint is worn out, and a paint gun 6 are painting the trunk part W3, which is one of the specific parts of the workpiece, when the trunk part W3 is being painted. A switch 24 that is turned on by a signal indicating that the switch 24 is turned on, and a relay 25 that is activated when this switch 24 is turned on.
A trunk paint detection circuit 26 is provided. A normally open contact 22a that is turned on by the operation of the relay 22 and a relay 25 that is connected in parallel to this
The determination circuit 28 has a normally open contact 25a that is turned on when activated, and has a relay 27 that is connected in series with these contacts and is activated when either one of them is turned on. The circuit 11 is provided. Among the contacts 22a and 25a in this discrimination circuit 28, one contact 22a is turned on by the operation of the relay 22, and the other contact 25a is turned on by the operation of the relay 22.
a is turned on by the operation of the relay 25.

The discrimination circuit 18 of the present invention includes a normally open contact 27a that is turned on when the relay 27 is activated, a normally open contact 15b that is connected in series with the normally open contact 27a that is turned on when the relay 15 is activated, and these contacts 27a and 15b. and a relay 17 that operates when both are turned on. The alarm circuit 20 has an alarm lamp R and an alarm buzzer B connected in parallel to the relay 17, and further includes a normally closed contact 19 for resetting.
This alarm circuit 20 is provided with a self-holding normally open contact 17a operated by a relay 17. Incidentally, a switch for stopping the conveyor 1 may be incorporated into the alarm circuit 20.

Next, to explain the operation, when the paint gun 6 is painting the hood part W1, the switch 21 is activated by a signal indicating that the hood part W1 is being painted.
turns on, relay 22 operates and its contact 2
2a is turned on. Moreover, when the painting gun 6 is painting the trunk part W3, the trunk part W3
The contact 24 is turned on by the signal indicating that the paint is being painted, and the relay 25 is activated to close the contact 2.
5a is turned on. Therefore, relays 22 and 2
When one relay among 5 is activated, relay 2
7 is activated and its contact 27a is turned on. In this state, for example, if the limit switch LS is accidentally turned on for some reason, the contact 15a is activated by the relay 15, the relay 17 is energized, and the alarm lamp R and alarm buzzer B are activated. Further, a circuit not shown is activated to stop the movement of the conveyor. Since the contact 17a is self-holding, the lamp R will continue to light up and the buzzer B will continue to light unless the reset contact 19 is turned off.
continues to operate.

Under normal conditions, when the hood W1 is being painted or the trunk W3 is being painted, the limit switch LS is in the OFF state, so contact 15b
is off, the alarm circuit 20 is not energized, and even if the paint gun 6 moves from the B position to the C position and the limit switch LS is activated at the C position, at this time, the hood part W1 or the trunk Since part W2 is not painted,
The contact 27a is off, and the alarm circuit 20 is not energized.

In the illustrated embodiment, the limit switch is activated both when the painting gun 6 is painting the hood part W1 and when painting the trunk part W3.
If the LS malfunctions for some reason and turns on, it is possible to issue an alarm, but in order to detect malfunction only in the hood section W1 or only malfunction in the trunk section W3, relay 22 Or directly contact 27a by relay 25
All you have to do is make it work.

As described above, according to the present invention, there is an ascent limit detection circuit that has a relay that operates when the coating gun reaches the ascent limit position, and a coating gun that paints specific parts such as the hood and trunk of the workpiece. Since the discriminating circuit has a discriminating circuit that issues an alarm when each of the relays of the discriminating circuit has a relay that operates when the sprayer is activated, it is also possible to detect malfunction of the equipment that detects the upper limit position of the paint sprayer. It is possible to improve the reliability of the coating machine.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an automobile paint sprayer, Fig. 2 is a circuit diagram showing a conventional paint gun malfunction detection circuit, and Fig. 3 is a paint gun malfunction detection circuit according to an embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 1...Conveyor, 5...Painting machine body, 6...Painting gun, 11...Painting defect detection circuit, 16...Rise limit detection circuit, 18...Discrimination circuit, 20...Alarm circuit, 23...Hood Paint detection circuit, 26... Trunk paint detection circuit, 28... Discrimination circuit.

Claims (1)

[Scope of utility model registration request] A coating machine that paints a workpiece by moving the workpiece relative to a main body of the coating machine to which a coating gun is mounted so as to be movable up and down, the coating machine having a relay that operates when the coating gun reaches the upper limit position. It has a rise limit detection circuit, a discrimination circuit having a relay that is activated when the painting gun is painting a specific part of the workpiece, and a discrimination circuit that issues an alarm when at least each of the relays is activated together. Paint gun malfunction detection circuit.