JPS63135695A - Safety device for machine tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a stop system that is attached to a machine tool such as a press machine, and stops the machine tool when an abnormal object enters the monitored range and blocks the light beam. This invention relates to a light beam type safety device that generates a signal.

<Conventional technology> Conventionally, general optical safety devices installed on machine tools have multiple emitters and receivers installed facing each other in the hazardous area on the front of the machine tool, that is, the area to be monitored. When at least one of the multiple optical axes is blocked, the machine tool will be stopped because a part of the worker's body has entered the monitored range. It is configured.

<Problems to be solved by the invention> In such conventional optical beam safety devices, the number of emitters and receivers are arranged side by side at a predetermined interval, equal to the number of optical axes. When trying to set the optical axis, it is necessary to use a large number of emitters and receivers in line.

In addition, since light emitting diodes that emit normal light are generally used for floodlights, when the range to be monitored is wide and the optical axis distance is long, the optical axis diameter becomes thick and diffuses, and the optical axis spacing, that is, the light emitting/receiving element. There was a problem in which the installation interval could not be set in detail.

Additionally, at sites where machine tools are used, when machining is performed using a press machine, bender, etc., there may be cases where machining must be performed with part of the workpiece or jig protruding from the monitoring range of safety equipment. As shown in FIG. 9, when the processed material 40 protrudes from the monitored range, the optical axis emitted from the light projecting section 41 is blocked by the processed material 40 and does not enter the light receiving section 42. When such processing must be carried out because the safety device is activated and the press machine etc. cannot be used, the optical axis, which is blocked by the processing material etc., is used in an invalid state. For this reason,
There was a problem that the region 43 from the processed material 40 to the light receiving section 42 became a blind spot for the safety device as it had no optical axis.

<Means for Solving the Problems> The present invention was made to solve the above problems, and it eliminates the need to install a large number of emitters and receivers side by side as in the past, and uses a narrow optical axis. Machine tool safety that can generate multiple optical axes at narrow intervals, ensuring safety without creating blind spots even when machining materials protrude from the monitored range. The device is configured as follows.

That is, the machine tool safety device of the present invention, as shown in the overall configuration diagram of FIG. 1 and two reflectors 12a and 12b are attached to each parabolic mirror 3a.
, 3b, each parabolic mirror 3
Rotating mirrors 2a and 2b are located near the focal points of a and 3b, respectively.
are arranged, and two laser oscillators emit laser light toward each rotating mirror 2a, 2b so as to generate a large number of parallel optical axes between the two pairs of parabolic mirrors 3a, 3b and the reflectors 12a, 12b. 1a and lb are arranged, and two light receivers 5a and 5b are provided for receiving the laser light reflected by the reflectors 12a and 12b and returned on the respective optical axes via the half mirrors 4a and 4b. The control section 20 inputs the light reception data sent from the detection section 10 and outputs a stop signal to stop the machine tool when the optical axis is blocked.

The detection unit 10 includes two laser excavators la and l.
a light emitting and scanning processing means 6 that drives the mirror 2b to project a laser beam, and scans the optical axis by rotating the two rotating mirrors 2a and 2b by a predetermined angle by a motor, and a light receiver 5.
A light reception processing means 7 is provided which outputs a light reception data signal based on the light reception signal sent from the detectors 10a and 5b, and the control section 20 determines whether or not all optical axis light is received based on the light reception data signal sent from the detection section 10. and a stop command means 9 which outputs a stop signal and instructs the machine tool to stop if not all the optical axis light is received. When the rotating mirrors 2 , a , 2 b are rotated synchronously by a predetermined angle while projecting laser light, the laser beam is reflected by each rotating mirror 2 a , 2 b and reflected by each parabolic mirror 3 .
A, 3b are irradiated while gradually changing the angle of incidence,
Laser beams are projected in parallel from the parabolic mirrors 3a and 3b toward the corresponding parabolic mirrors at regular intervals according to the rotation angles of the rotating mirrors 2a and 2b, and by scanning the laser beams, a large number of optical axes are It is formed between a pair of parabolic mirrors 3a, 3b and reflectors 12a, 12b.

At this time, the laser beam of each optical axis is reflected by the reflector 12a or 12.
b, passes through the parabolic mirror 3a or 3b and the rotating mirrors 2a, 2b again, and is reflected by the half mirrors 4a, 4b.
The light is received by the light receiver 5a or 5b on the opposite side. The light reception signals output from the light receivers 5a and 5b are taken into the light reception processing means 7, and light reception data is created for each scan. It is determined whether or not the beam is received by a bearing, and if any of the optical axes is blocked and the beam is not received by all optical axes, the stop command means 9 outputs a stop signal to the machine tool.

<Example> Embodiments of the present invention will be described below based on the drawings.

The optical system of the detection section of the safety device is constructed as shown in Figs. 2 and 3, and two parabolic mirrors 3a and 3b are placed in front of the dangerous area of the machine tool, that is, on both sides of the area to be monitored. So that the reflected optical axis is slightly shifted back and forth,
placed facing each other. And two reflectors 12a
, 12b are arranged on both sides facing each parabolic mirror 3a, 3b. The parabolic mirrors 3a and 3b are formed by forming a part of a spherical surface into a vertically thin arcuate shape, and always reflect the light projected toward the partial spherical surface from the approximate focal point in parallel toward the opposing reflectors 12a and 12b. It has a structure that
The reflectors 12a and 12b have a structure that always reflects incident light onto the same optical axis as the incident light. parabolic mirror 3
Rotating mirrors 2a, 2b (
For example, a polygon mirror) is provided, and a rotating mirror 2a,
2b has four reflective surfaces around it, and is driven to rotate accurately at a constant angle by rotating mirror motors lla and 11b (eg, stepping motors). 1a and 1b are HeN
A laser oscillator using an e-gas laser, a semiconductor laser, etc. irradiates a laser beam toward a part of the rotating mirrors 2a, 2b, respectively, and the laser beam reflected from the rotating mirrors 2a, 2b is transmitted to the inner surface of the parabolic mirrors 3a, 3b. It is placed in a position where it emits light. Between the laser oscillators 1a, lb and the rotating mirrors 2a, 2b, a condensing lens and half mirrors 4a, 4b inclined at about 45 degrees with respect to the optical axis are arranged. Below the half mirrors 4a and 4b, there is a light receiver 5a,
5b (for example, a photodiode, a phototransistor, etc.) is arranged to receive laser light emitted from a laser oscillator on the opposite side via half mirrors 4a and 4b.

As shown in the block diagram of FIG. 4, the safety device scans the laser beam by rotating rotating mirrors 2a and 2b, and connects two parabolic mirrors 3a and 3b and reflectors 12a and 12.
A detection unit 10 has two light receivers 5a and 5b that receive the laser light generated between the two points and returns on the optical axis via half mirrors 4a and 4b, respectively, and generates light reception data.
and a control section 20 that manually inputs light reception data from the detection section 10 and outputs a stop signal to stop the machine tool when there is a light blockage on any of the many optical axes generated by scanning.

In the detection unit 10, a microcomputer using a so-called one-chip CPU is used as a light emission scanning processing means and a light reception processing means. A ROM 16 that stores data, a RAM 17 that stores data such as the number of optical axes in a readable and writable manner, and an input/output circuit 18, and each unit connects to a common bus 19.
are connected to each other to transmit data and control signals. The input/output circuit 18 includes a rotating mirror motor ll.
a, a driver circuit for synchronously driving the llb, an amplifier, a filter, and an A/D converter for amplifying and filtering the received light signals inputted from the light receivers 5a and 5b, and then converting them into digital signals. It will be done.

The laser oscillators 1a and lb have a built-in drive circuit and a modulator, and emit laser light modulated at a specific frequency. The laser oscillators 1a and Ib are controlled to start and stop by a microcomputer, but operate continuously while the safety device is in operation. When a stepping motor is used as the motor for rotating mirror motors Ila and Ilb, the driver outputs a specific number of pulses each time each optical axis is generated to drive the two motors at a constant angle.

The number of optical axes setting device 13 is used to preset the number of optical axes generated by scanning, and is configured with, for example, a digital switch or a numeric keypad. When generating, the number of optical axes is 10.
Set to 0.

The control unit 20 includes a microcomputer that takes in the received light data signal from the detection unit 10, determines whether or not all optical axes are received, and outputs a stop signal when a light blockage occurs, and serves as a stop command unit. , a check switch 21 operated to check whether the main relay contacts are welded, a welding detection circuit 22 as shown in FIG. It is equipped with The microcomputer of the control unit 20 is configured using a one-chip CPU, similar to that of the detection unit 10 described above, and includes a CPU 24 that executes optical axis determination and output processing of a stop signal based on a predetermined program, and program data. It consists of a ROM 25 that stores fixed information such as, a RAM 26 that stores light reception data sent from the detection unit 10 in a readable and writable manner, and an input/output circuit 27. The input/output circuit 27 is the detection unit 10
The input/output circuit 27 is connected to the input/output circuit 18 to transmit synchronization signals and take in received light data. is connected.

The stop circuit 31 is composed of a driver and a main relay, and is configured to operate the main relay in response to a stop signal output from the input/output circuit 27 to stop the machine tool. Auxiliary stop circuit 3
0 consists of a driver and an auxiliary relay, and is configured to operate the auxiliary relay to stop the machine tool if the main relay of the stop circuit 31 malfunctions such as welding.

As shown in the connection diagram in Figure 5, contact 1x of main relay 1x
Contacts a, lxb and contact 2xa of auxiliary relay 2x are connected in parallel between the stop input terminals of the machine tool, and when the main relay is de-energized, contact 1xb is turned on and stopped, and when the auxiliary relay is energized, contact 2xa is connected. turns on and becomes stopped.

The welding detection circuit 22, which detects the welding state of the main relay, is constructed by connecting a photocoupler PC to one contact 1xa of the main relay, as shown in FIG. outputs a detection signal. In other words, when the stop signal is output and the main relay is de-energized, contact 1xa is off, so no current flows to the output side of the photocoupler PC, a high level detection signal is output, and a stop signal is output. When the main relay is energized, contact IXa
is turned on, the output side of the photocoupler PC becomes conductive, and a low-level detection signal is output.

The detection unit 10 configured as described above is installed near the monitored part of the machine tool, and the control unit 20 is installed near the control panel of the machine tool, but each of the detection unit 10 and the control unit 20 has a built-in microcomputer. However, since data is transmitted serially, the lines between them may be two trees, one for signals and one for data.

Next, the operation of the detection section 10 of the safety device will be explained based on the flowchart shown in FIG.

The CPU 15 of the detection unit 10 first performs initialization such as resetting various registers in step 100, and then
At step 110, the set number of optical axes set by the number of optical axes setter 13 is read and stored in the RAM 26. Next, in step 120, the laser oscillators 1a and lb are started,
Laser beams are oscillated from laser oscillators la and lb. The laser light is modulated by a modulator at a frequency of, for example, about 5 MH2, and the modulated laser light is continuously oscillated.

Next, in step 130, a synchronization signal is input from the control unit 20, and in step 140, a specific number of drive pulses are output to the rotating mirror motors lla and llb to rotate the rotating mirrors 2a and 2b at a constant angle. . At this time, the laser beams emitted from the laser oscillators 1a, lb pass through the half mirrors 4a, 4b, are reflected by the rotating mirrors 2a, 2b, hit the inner peripheral surfaces of the parabolic mirrors 3a, 3b, and are reflected there. As shown in FIG.
This corresponds to 2b. The laser beams reflected by the reflectors 12a and 12b return on the same optical axis and pass through the parabolic mirrors 3a and 3b, the rotating mirrors 2a and 2b, and the half mirrors 4a and 4b, respectively, to the light receivers 5a and 5b. Light is received.

When the light receivers 5a and 5b receive the laser light, a light reception signal is output, and after the light reception signal is amplified, it is passed through a filter circuit to remove the influence of disturbance light, and in step 150,
The received light signal is passed through the A/D converter and converted into a digital signal, and then read into the CPU 15. And step 1
At step 60, it is determined whether or not light has been received based on the light reception signal, and when it is determined that light has been received when the level of the light reception signal is equal to or higher than a predetermined value, the process proceeds to step 170, where a light reception pulse signal (light reception data) is detected.
is output to the control section 20. Meanwhile, at step 160,
If it is determined that one of the light receivers 5a and 5b is blocked,
Without executing step 170, the process directly jumps to step 180, subtracts "1" from the set number of optical axes, and then determines whether the subtracted number of optical axes is O in step 190.

When the number of optical axes to be subtracted is not O, the process returns to step 140 and the rotating mirror motor 11a is activated again.

A driving pulse is output to 11b to further rotate rotating mirrors 2a and 2b at a constant angle. As a result, the laser beam reflected by the rotating mirrors 2a and 2b is transmitted to the parabolic mirror 3a.
, 3b, and the next optical axis is formed immediately below the previously generated optical axis. Then, the laser beam returned on the optical axis is received by the light receivers 5a and 5b on the same side in the same way as above, and the light receivers 5a and 5b
In step 150, the light reception signal outputted from the light reception signal is converted into a digital value and read into the CPU 15, and after determining whether or not light is being received, the CPU 15 transmits the light reception pulse signal to the control section if the two light receivers 5a and 5b are in the light reception state. 20 and further subtracts "1" from the number of optical axes, thus step 140
- Step 190 is repeated, and when the number of subtracted optical axes reaches 0, one scan by the laser beam is completed. Then, the process returns from step 190 to step 130, and after inputting the synchronization signal sent from the control section 20, steps 140 to 190 are repeated, and scanning by the laser beam is repeated in the same manner as above.

Next, the operation of the control section 20 will be explained based on the flowchart shown in FIG.

First, in step 200, the CPU 24 of the control unit 20
A synchronizing signal is output to the detection section 10, and then in step 210, a light reception pulse signal (light reception data) sent from the detection section 10 is read. Then, in step 220, it is determined whether the check switch 21 that checks the welding of the contacts 1xa and lxb of the main relay for stopping is turned on, and if the check switch 21 is not turned on, then step 2
Proceeding to step 30, based on the light reception data sent from the detection unit 10, it is determined whether all optical axes generated by scanning the laser beam are in the light receiving state, and if there are no optical axes blocked and all optical axes are in the light receiving state. If so, then in step 240, a safety signal is output to the stop circuit 31. At this time, the main relay 1x of the stop circuit 31 is energized by the safety signal and closes the contact 1xa and opens the contact 1xb, so it stops. Output is produced, the machine tool is not stopped.

On the other hand, if it is determined in step 230 that there is a light-shielded optical axis and that all the optical axes are not in the light-receiving state, the process proceeds to step 250, in which the output of the safety signal is stopped and the stop circuit 31
The machine tool is stopped by deenergizing the main relay 1x and turning on its contact 1xb. Subsequently, from step 240 or from step 250 to step 26
0, and the main relay contacts 1xa and lx of the stop circuit 31
It is determined whether or not b is in a welded state based on the output signal from the welding detection circuit 22, and if the main relay contacts are not welded, this process is finished, and if the main relay contacts are welded, Next, the process proceeds to step 320, where a welding abnormality signal is output to the auxiliary stop circuit 30.

The auxiliary stop circuit 30 energizes the auxiliary relay 2x by the manual input of the welding abnormality signal, closes its contact 2xa, and performs stop control, thereby stopping the machine tool.

On the other hand, if it is determined in step 220 that the check switch is turned on, steps 270 and subsequent steps are executed to check the operation of the stop circuit 31. That is, in step 270, the output of the safety signal is stopped and the stop circuit 3
Deenergize main relay 1 and turn on contact 1xb to stop the machine tool. Then, in step 280, a welding abnormality detection signal is output to the auxiliary stop circuit 30, thereby energizing the auxiliary relay of the auxiliary stop circuit 30, and the contact 2xa
is turned on, and further in step 290, "stop circuit 3" is turned on.
1, the main relay of the stop circuit 31 is energized and the contact 1xb is turned off. After turning on and off the contacts of the main relay in this way, the process proceeds to step 300.
It is determined whether or not the contacts of the main relay are in a welded state based on the output signal from the welding detection circuit 22. If the contacts of the main relay are welded, the process proceeds to step 320 and a welding abnormality signal is sent to the auxiliary stop circuit 30. output to stop the machine tool. On the other hand, if there is no contact welding of the main relay, then step 310
, the output of the welding abnormality signal is stopped, and the auxiliary stop circuit 3
0 stop control is canceled and the inspection operation is completed.

In this way, by repeatedly executing steps 200 to 260 or 320, the light reception data sent from the detection unit 10 is checked, and if there is a blocked optical axis, the safety signal is stopped and the stop circuit is activated. 31 performs stop control to stop the machine tool. At the same time, the welding condition of the main relay of the stop circuit 31 is also checked.
If welding is detected, a welding abnormality signal is output to the auxiliary stop circuit 3°, and the auxiliary stop circuit 30 controls the stop of the machine tool. Further, when the check switch 21 is turned on, the process advances from step 220 to step 270, and steps 270 to 310 are executed to forcibly turn on and off the contacts of the main relay of the stop circuit 31, and the welded state of the contacts is is checked.

As described above, in the safety device of the present invention, laser light is emitted from both sides of the monitored area, and the laser light that is reflected by the reflectors installed oppositely on both sides and returned on the same optical axis is received by the light receiver. Due to the structure, when it is necessary to perform work by protruding jigs and processing materials from the working area of the machine tool, from the monitored range, that is, the area where the optical axis is formed, the protruding parts should be protruded as shown in Figure 8. If the reflector 39 is bonded to a location where the processed material 40 or the like blocks light from the optical axis, monitoring can be performed without creating a blind spot. That is, the optical axis blocked by the protruding processing material 40 hits the reflectors 39 on both sides and is reflected, and the parabolic mirrors 3a, 3b,
The light is received by the light receivers 5a, 5b through the rotating mirrors 2a, 2b and the half mirrors 4a, 4b, creating optical axes on both sides of the processed material, and monitoring the monitored range without creating blind spots as in the past. be able to.

<Effects of the Invention> As explained above, according to the machine tool safety device of the present invention, since the optical axis is generated by a laser beam, it is possible to project light over a long distance with the optical axis narrowly focused. Even if the range to be monitored is wide and the optical axis length is long, the optical axis diameter is thick and does not spread, and the optical axis gap can be set narrow, allowing for narrow-eyed monitoring. A laser beam is emitted, the reflected laser beam is returned on the same optical axis by a reflector installed on the opposite side, and the returned laser beam is received by a receiver, so that it can be seen from the monitored area. Even when machining is performed with protruding materials or jigs, by gluing reflectors on both sides of the materials or jigs (where light is to be blocked), monitoring can be done without creating blind spots where the optical axis disappears, ensuring safety. can.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of the present invention, Figs. 2 to 8 show examples thereof, Fig. 2 is a front view of the optical system of the detection section, Fig. 3 is a plan view thereof, and Fig. 4 is A block diagram of the safety device, Figure 's5 is a connection diagram of the welding detection circuit, Figure 6 is a flowchart showing the operation of the detection section, Figure 7 is a flowchart showing the operation of the control section, and Figure 8 is an explanation of other usage examples. 9 are explanatory diagrams of a conventional safety device. la, lb...laser oscillator, 2a, 2b...rotating mirror, 3a, 3b...parabolic mirror, 4a, 4b...half mirror 1 3a, 5b...light receiver, 6...emitter Optical scanning processing means, 7... Light reception processing means, 8... Optical axis determination means, 9... Stop command means, 10... Detection section, 12a, 12b... Reflector, 20... Control Department. Patent application: Toyo Electronics Co., Ltd.

Claims (1)

[Scope of Claims] Two parabolic mirrors are disposed on both sides of the monitored area facing each other with their optical axes shifted, and two reflectors are disposed on both sides facing each parabolic mirror, A rotating mirror is disposed approximately near the focal point of each parabolic mirror, and a laser beam is irradiated toward each rotating mirror so as to generate a large number of parallel optical axes between the two pairs of parabolic mirrors and the reflector. a detection unit including two laser oscillators, and two light receivers for receiving laser light reflected by the reflector and returned on each optical axis via a half mirror; A safety device comprising: a control section that inputs received light data sent from a detection section and outputs a stop signal to stop the machine tool when there is light shielding on the optical axis; A light emitting and scanning processing means drives a laser oscillator on the base to emit laser light, and scans the optical axis by driving the two rotary mirrors to rotate at predetermined angles by a motor; A light reception processing means for outputting a light reception data signal based on a light reception signal sent from the detection section is provided, and the control section includes an optical axis determination means for determining whether or not all optical axes are received based on the light reception data signal sent from the detection section. 1. A safety device for a machine tool, characterized in that a stop command means is provided for outputting a stop signal and commanding the machine tool to stop when the entire optical axis is not received.