JP3228980B2 - Safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device used for an NC machine tool or the like.

[0002]

2. Description of the Related Art Conventionally, when processing a workpiece using an NC machine tool, an operator first opens a protective cover of the machine tool while the machine tool is stopped, and attaches the work.
After the work is mounted, the protective cover is closed and the work is processed. After the work is completed and the machine tool is stopped, the protective cover is opened again to remove the processed work.

[0003] In a machine tool in which the above-mentioned operation is performed in a dangerous place having a movable portion, if the movable portion is erroneously operated during the operation due to a malfunction of the machine, an erroneous operation of the operator, etc. May cause damage to machine tools, workpieces or tools. Therefore, the NC machine tool is provided with a protective cover that can be opened and closed to prevent such dangers, and further includes a safety device as shown in FIG.

[0004] The protective cover is provided with a protective cover open / closed detection switch 7 for detecting the open / closed state, and the safety monitor 1 is connected to the protective cover open / closed detection switch 7. In order to further detect the rotation of the motor 5, the safety monitoring device 1 has an encoder 6 connected to the rotating shaft of the motor 5.
The output of the tachogenerator 16 is input, the interlock release switch 8 is connected, and connected to the trip coil of the main power switch 9 for opening and closing the power of the motor amplifier 4. The motor amplifier 4 is connected to a motor control unit (CNC) 3 that controls the motor 5 by feeding back the output of the encoder 6.

The operation of the safety device configured as described above will be described.

After the work of the workpiece is completed, when the machine tool stops and the protective cover is opened, an open signal is input to the safety monitoring device 1 from the protective cover open / close detection switch 7.
The safety monitoring device 1 to which the open signal has been input starts monitoring the rotation of the motor 5 by the encoder 6 and the tachogenerator 16. At this time, when the motor 5 starts rotating due to a malfunction of the machine or a malfunction of the operator, the encoder 6
And the tachogenerator 16 detects the rotation of the motor 5 and sends the detection result to the safety monitoring device 1. Then, the safety monitoring device 1 outputs to the trip coil of the main power switch 9 to open the main power switch 9. When the main power switch 9 is opened, the power of the motor amplifier 4 is cut off and the motor 5 is turned off.
Stops. The stop operation of the safety monitoring device 1 operates when the interlock release switch 8 is selected to be open.

[0007]

However, in the above-mentioned safety device, when the protective cover is opened while the motor is stopped, the motor is erroneously operated due to a malfunction of the machine or an erroneous operation of the operator.
Since the detection is performed after the motor 5 starts rotating, the power supply of the motor amplifier 4 is cut off after that, so that it takes time until the motor 5 starts operating and stops.

Further, since the power supply is cut off at only one place, there is a problem that the safety is not sufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a safety device capable of ensuring safety quickly and with high reliability in consideration of such conventional problems.

According to the present invention, an open / close signal indicating the open / close state of the protective cover (or door) is input, and when the input open / close signal is an open signal, the motor driving means of the motor of the machine main body is opened. a first control means for outputting a first cutoff signal for cutting off the first power supply switching means provided on the power supply side, the open-close signal
Inputs the detection signal indicating the open or closed state of the first power switching means and said detection signal the switching signal is an open signal is close signal
If it is, the motor and the power supply - between data, the first
(1) A second power supply switching means provided in series with
And a second control means for outputting a second shut-off signal for shutting off the power supply opening / closing means.
And the first control of each of the safety detection / interruption means.
Logic of each of the first cut-off signals output from the means
AND circuit for taking the product and outputting the product to the first power switching means
And the second control of each of the safety detection / shutoff means.
Logic of each of said second cut-off signals output from the means
An OR circuit for taking the sum and outputting the sum to the second power supply switching means;
A safety device comprising:

[0011]

According to the present invention, there are provided two safety detecting / cutting means.
There, the first control means receives the switching signal indicating the open or closed state of the protective cover (or doors), when the switching signal is open signal, outputs a first cutoff signal for cutting off the first power supply switching means And a second control means for shutting off the second power supply opening / closing means when the detection signal indicating the closed state of the first power supply opening / closing means is detected after the first cutoff signal is output. Outputs the cutoff signal.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing embodiments thereof.

FIG. 1 is a configuration diagram of a safety device according to an embodiment of the present invention. That is, in order to prevent harm to an operator and damage to a machine tool, a work or a tool, an openable / closable protective cover (or door) provided on the NC machine tool has a protective cover open / closed detection for detecting an open / closed state. A switch 7 is provided, and the output of the protection cover open / close detection switch 7 is output to the safety monitoring device 1 and the machine control unit (P
MC) 2.

Among them, the safety monitoring device 1 includes an output of a voltage / current detection circuit 10 provided on a power supply side of a motor amplifier 4 as a motor driving means for driving the motor 5,
An interlock release switch 8 is connected, and two outputs are connected to an OR circuit 13 and an AND circuit 1 to cut off the power.
4 input terminals. The motor amplifier 4 is provided with a converter 15 for converting AC into DC and an inverter 12 for generating AC for driving the motor 5 from the DC. The output of the voltage / current detection circuit 10 is used for detecting the open / closed state of the electromagnetic switch 11.

The safety monitoring device 1 includes, for example, AND circuits 31 and 32, an ONDELAY circuit 19, and the like as shown in FIG.

On the other hand, the output of the voltage / current detection circuit 10 and the interlock release switch 8 are connected to the machine control unit 2 similarly to the safety monitoring device 1, and the two outputs are connected to the input terminals of the OR circuit 13 and the AND circuit 14. Each is connected. Further, the machine control unit (PMC) 2 is connected to a motor control unit (CNC) 3 for controlling the motor amplifier 4, and its motor
The output of the encoder 6 connected to the motor 5 is connected to the motor control unit 3.

On the other hand, on the power supply side of the motor amplifier 4, an electromagnetic switch 1 having a suction coil 23 as first power supply switching means is provided.
1 is connected to a power supply side of the electromagnetic switch 11, and a main power switch 9 having a trip coil 27 as a second power switch is connected to the main power switch 9.
A 200 volt power supply is connected. The output of the AND circuit 14 is connected to the suction coil 23 of the electromagnetic switch 11, and the trip coil 27 of the main power switch 9 is
The output of the R circuit 13 is connected. That is, two safety detection and shutoff devices are provided in parallel and in series to form a double structure.

Next, the operation of the above embodiment will be described.

First, when the protective cover is kept closed while the movable part of the NC machine tool is stopped, a signal to close the electromagnetic switch 11 is output from the safety monitoring device 1 and the machine control unit 2, and the signals are output. The closing signal is input to the AND circuit 14, and as a result, the attraction coil 23 is energized, and the electromagnetic switch 11
Remain closed, and a voltage is applied to the motor amplifier 4.

Thereafter, for example, when the protective cover is opened to mount a work, an open signal is input from the protective cover opening / closing detection switch 7 to the safety monitoring device 1 and the machine control unit 2. When the opening signal of the protective cover is input, the safety monitoring device 1 and the machine control unit 2 immediately stop the closing signal output to the AND circuit 14. For example, in the safety monitoring device 1, the opening signal of the protective cover opening / closing switch 7 is
1 and the input and the cancel signal of the interlock release switch 8 (in this case, the cancel signal is OF
The logical product of the inverted input of F) and the inverted input is output to the AND circuit 14, and as a result, the energization of the attraction coil 23 is stopped, the electromagnetic switch 11 shifts to the open state, and the power supply of the motor amplifier 4 is cut off. Similarly, an open signal is output from the machine control unit 2 to the AND circuit 14.

At this time, even if one of the safety monitoring device 1 and the machine control unit 2 fails or malfunctions, the AND circuit 1
4, the opening signal to the electromagnetic switch 11 works effectively.

Next, although the safety monitoring device 1 and the machine control unit 2 output an open signal, the electromagnetic switch 11 remains closed due to a failure of the AND circuit 14 or the electromagnetic switch 11 side. Then, since the voltage monitoring circuit 10 is always connected to the safety monitoring device 1 and the machine control unit 2, the safety monitoring device 1 and the machine control unit 2 output a signal indicating that the motor amplifier 4 is closed on the power supply side. Is entered. The input signal and the protective cover open signal are output from the AND circuit 32 in the safety monitoring device 1 and the machine control unit 2, and output an open signal for opening the main power switch 9 to the OR circuit 13. The OR circuit 13 energizes the trip coil 27 in response to the open signal to open the main power switch 9 and reliably shut off the power supply of the motor amplifier 4.

In this case, even if one of the safety monitoring device 1 and the machine control unit 2 fails or malfunctions, the OR circuit 13
Thus, the open signal to the main power switch 9 works effectively.

As described above, when the protective cover is opened, the electromagnetic switch 11 is opened to shut off the power supply of the motor amplifier 4, so that even if an erroneous operation or the like occurs, safety is ensured. If the switch 11 is not opened due to a failure or the like, the main power switch 9 is opened, so that the motor is securely opened.
The power of the amplifier 4 is cut off.

In the above-described embodiment, the first control means and the second control means are provided as one set, and are provided in the safety monitoring device 1 and the machine control unit 2 respectively. However, needless to say, it may be provided in only one of the safety monitoring device 1 and the machine control unit 2.

In the above embodiment, the voltage and the current on the power supply side of the motor amplifier 4 are detected. However, only one of the voltage and the current may be detected.

In the above-described embodiment, the second power supply switching means is provided on the power supply side of the first power supply switching means. However, the present invention is not limited to this, and may be provided between the power supply and the motor 5.

In the above embodiment, the first power switching means is the electromagnetic switch 11 and the second power switching means is the main power switch 9.
However, the present invention is not limited to this, and it is sufficient that opening / closing control can be performed. For example, a semiconductor relay may be used.

FIG. 2 is a configuration diagram of a safety device according to the related art of the present invention . That is, the open / close signal of the protection cover open / close detection switch 7 provided on the protection cover and the output of the voltage / current detection circuit 10 for detecting the power supply voltage of the motor amplifier 4 are output by the safety monitoring device 1 and the machine control unit (PMC) 2. Has been entered.

In the safety monitoring device 1, an open / close signal of the protective cover open / close detection switch 7 and a cancel signal of the interlock release switch 8 via the machine control unit (PMC) 2 are set to AN.
The signal is input to the D circuit 31 and its output is inverted and connected to the NAND circuit 33 provided in the motor amplifier 4. The output of the voltage / current detection circuit 10 and the output of the AND circuit 31 are input to the AND circuit 32, and the output is connected to the trip coil 27. A detection signal of the encoder 6 is input to the other input of the NAND circuit 33 via the decoding circuit 41. Part of the output of the NAND circuit 33 is connected to the attraction coil 23 of the electromagnetic switch 11, and part of the output is
It is connected to the ND circuit 34. The other input of the AND circuit 34 is connected to an inverter drive signal from the servo processor 40. The output of the AND circuit 34 is connected to the inverter 12 via the drive circuit 42.

Next, the operation of the related art will be described.

First, when the protective cover is closed, the closing signal is transmitted to the safety monitor 1 and the machine controller (PMC) 2.
Is input to In the safety monitoring device 1, the input and inverted close signal and the cancel signal (usually not canceled) from the machine control unit (PMC) 2 are input to the AND circuit 31, and a part of the output is supplied to the ONDELAY circuit 19. Through the input of the AND circuit 32, and is partially inverted to N
Input to the AND circuit 33. From the NAND circuit 33, regardless of the presence or absence of the detection signal of the encoder 6, the attraction coil 23
And outputs the same to the AND circuit 34. The power is supplied to the motor amplifier 4 by this signal, and the drive circuit 42 of the inverter 12 becomes operable.

Next, when the protective cover is opened with the motor 5 stopped, the protective cover open / close detection switch 7 outputs an open signal. The safety monitoring device 1 takes a logical product of the open signal and the cancel signal from the machine control unit (PMC) 2 and sends the logical product to the NAND circuit 33 in the motor amplifier 4. At this time, a stop state signal of the motor 5 from the decoding circuit 41 causes
Immediately, the energization of the suction coil 23 of the electromagnetic switch 11 is stopped, and the AND circuit 34 outputs a stop signal so that the drive circuit 42 cannot be driven.

At this time, if the electromagnetic switch 1
1 is not released, the voltage / current detection circuit 10
Detects the voltage on the power supply side of the motor amplifier 4, and the closed state signal of the electromagnetic switch 11 is transmitted to the safety monitoring device 1 and the machine control unit (P
MC) 2. In the safety monitoring device 1, the closed state signal is input to the AND circuit 32, and the logical product of the input signal and the open signal of the protective cover open / close detection switch 7 is output to the trip coil 27 and output to the main power switch. 9 is opened to surely shut off the power supply of the motor amplifier 4.

Next, when the worker accidentally opens the protective cover during the operation of the NC machine tool, an open signal of the protective cover open / close detection switch 7 is input to the machine control unit (PMC) 2 and the machine control unit (PMC) 2 outputs a deceleration stop signal of the motor 5 to the servo processor 40 via the CNC 3. The servo processor 40 outputs a stop signal of the inverter 12 to the AND circuit 34 to stop the motor 5. Until the motor 5 stops, the NAND circuit 33 keeps energizing the attraction coil 23 of the electromagnetic switch 11 by turning off the motor 5 stop state signal output from the decoding circuit 41. Thereafter, when the motor 5 stops and the encoder 6 detects the stop of the motor 5, the NAND circuit 33 stops the energizing of the attraction coil 23 by the signal, and the electromagnetic switch 11 is turned off.
Open.

As described above, when the motor 5 is stopped, when the protective cover is opened, the electromagnetic switch 11 is immediately opened, and when the motor 5 is operating, the protective switch is erroneously protected. When the cover is opened, the motor 5 is stopped before the electromagnetic switch 11 is opened. Further, the open / close state of the electromagnetic switch 11 is checked. If the open state is not checked, the main power switch 9 is opened to surely shut off the power of the motor amplifier 4.

When the interlock release switch 8 is pressed, a signal is input to the machine control unit (PMC) 2 and a cancel signal is output from the machine control unit (PMC) 2 to the safety monitoring device 1 to open and close the protective cover. The open signal of the switch 7 is invalidated so that the safety monitoring device 1 does not operate.

In the related art , the electromagnetic switch 11
Was detected by the voltage / current detection circuit 10,
Instead, as shown by the two-dot chain line in FIG.
The detection may be performed using one auxiliary b-contact (or a-contact). Alternatively, the detection may be performed by using both the auxiliary b-contact (or a-contact) and the voltage / current detection circuit 10.

The present invention is not limited to NC machine tools,
It is also applicable to safety devices of other machines.

[0040]

As apparent from the above description, the present invention can provide a safety device that can ensure safety quickly and reliably.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a safety device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a related technology of the present invention .

FIG. 3 is a configuration diagram of a conventional safety device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Safety monitoring device 2 Machine control part (PMC) 4 Motor amplifier 5 Motor 7 Protective cover open / close detection switch 9 Main power switch 10 Voltage / current detection circuit 11 Electromagnetic switch 13 OR circuit 14 AND circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B23Q 11/00

Claims (1)

(57) [Claims] An open / close signal indicating an open / close state of a protective cover (or a door) is input, and when the input open / close signal is an open signal, a power supply side of a motor driving means of a motor of the machine body. enter a first control means for outputting a first cutoff signal for cutting off the first power supply switching means is provided, and a detection signal indicating the open or closed state of the switching signal and the first power supply switching means to the If the detection signal switching signal is in an open signal is in the closed signal, the motor and the power supply - between the motor, the second power supply switching means are provided to connect the first power supply switching means and in series and a second control means for outputting a second cutoff signal for blocking, two safety detection
· Shutoff means and the first control means of each of the safety detection and shutoff means
AND of each of the first cutoff signals output from
AND circuit for outputting to the first power supply switching means, and the second control means of each of the safety detection / cutoff means
The OR of each of the second cutoff signals output from
An OR circuit for outputting to the second power supply switching means.
Safety device according to claim that there were example.