JPH055443Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an optical transmission type touch probe device used for the purpose of measuring the machined shape of a workpiece in a machine tool such as a machining center.

Conventional Technology In machining centers, various tools are automatically gripped by a chuck, and complex machining is continuously performed with a single device. In such machining centers, touch probes are often used for purposes such as centering the inner and outer diameters of the workpiece before machining, or checking the shape and dimensions of the workpiece after machining.

As shown in FIG. 5, this touch probe 1 is used by being held by a chuck 2 instead of a cutting tool such as a drill. A stylus 3 is protruded from the tip of the touch probe, and when the tip of the stylus 3 comes into contact with a workpiece or the like, a built-in switch detects this. A plurality of light emitting diodes are arranged on the outer circumferential surface of the touch probe 1, and this switch
The ON/OFF signals are FM modulated and projected to the outer periphery.

A receiver head 4 is fixedly installed near the chuck 2, which receives the modulated light from the touch probe 1, converts it into an electrical signal, and sends it through a signal cable 5 to an interface board 7 installed in the NC control device 6. Send to. The NC control device 6 receives an ON/OFF signal from the interface board 7 indicating whether the stylus 3 has contacted a workpiece, etc., and calculates target measurement data from the current position data of the workpiece, etc.

Here, touch probe 1 is used like other tools.
Since the chuck 2 is moved between the tool holder and the chuck 2 by a predetermined transfer mechanism, this driving power cannot be supplied from the outside via an electric wire. For this reason, it has a built-in power battery. In order to extend battery life, the light emitting circuit, which consumes a large amount of power, is operated only when it is in use. This is done by providing a flash light source on the receiver head 4 and a single light receiving element on the touch probe 1. When the flash light source is turned on once at startup, and the light receiving element of the touch probe 1 receives this light, the light receiving element of the touch probe 1 receives this light. , the light emitting circuit of the touch probe 1 is activated.

Problems to be Solved by the Invention In the conventional optical transmission touch probe described above, the touch probe is activated by flash light emitted from the receiver head. It is necessary to provide a large-diameter lens system and a high-voltage generation circuit. This has the disadvantage that the receiver head becomes larger.

Since this receiver head faces the chuck, it must be installed occupying a part of the working space where tools, workpieces, etc. move, and the large size of the receiver head poses a restriction on installation.

Means for Solving the Problems The present invention has been developed in view of the above-mentioned conventional problems, and the means for solving the problems are removably attached to the cutting tool mounting position of the machine tool, and are attached to the tip of the tool. A touch probe that detects whether the protruding stylus has touched the workpiece using a built-in switch and sends this to the outside as an optical signal, and a touch probe that faces the touch probe and receives the optical signal emitted from the touch probe. The touch probe includes a plurality of light emitting elements and a plurality of light receiving elements distributed around the outer circumference of the body, and a built-in switch that detects when the touch probe is turned on and when it is turned off. a light emitting circuit that changes the frequency of a light emitting current flowing through the plurality of light emitting elements at different times; and when modulated light for operation command from a receiver head is input to at least one of the plurality of light receiving elements; The light emitting circuit is provided with a light receiving circuit that turns on the power for driving the light emitting circuit, and the receiver head is provided with a light emitting element for operation commands, and a light emitting element for issuing operation commands only when the touch probe is in use. A light emitting circuit that supplies a light emitting current with a predetermined modulation frequency, a receiving light receiving element, and processing the output of the light receiving element, determining whether the received frequency is a high frequency or a low frequency, and indicating that reception is in progress. This is an optical transmission type touch probe device characterized by being provided with a light receiving circuit that generates a carry signal indicating that an ON signal is being input, and a touch output signal indicating that an ON signal is being input.

Operation In the above configuration, the modulated light for operation command from the receiver head is received by the touch probe regardless of the mounting direction of the touch probe, since a plurality of light receiving elements are distributed around the outer periphery of the touch probe.

Furthermore, since the above-mentioned operation command from the receiver head is carried out using modulated light, the light emitting element of the receiver head can reliably perform light emission even when a small LED is used, eliminating the influence of ambient light.

The light emitting circuit of the touch probe is configured to receive power only when the modulated light for operation command is being emitted from the receiver head, so whether or not the light emitting element of the touch probe is emitting light depends on Controlled only by this operation command modulation,
Easy to configure and reliable.

Example The present invention will be described below with reference to Examples.

The optical transmission type touch probe device 10 of the present invention has an external configuration as shown in FIG. 1, in which 11 is a touch probe, 12 is a receiver head, and 13 is an interface board.

Here, the touch probe 11 is composed of a holding part 11a that is held by the chuck of a machine tool, a main body part 11b containing an electronic circuit, etc., and a stylus 11a protruding from the main body part. And the main body part 11
At a predetermined height position of b, as shown in FIG.
Light receiving elements 15, 15, .

The receiver head 12 includes an optical system 12 such as a lens.
A is provided on the front, and a light emitting element for operation commands is installed inside.
It has a built-in light receiving element for receiving ON/OFF signals.

The interface board 13 is assembled with a circuit for interfacing the receiver head 11 with the controller of the NC control device.

Data is transmitted between the touch probe 11 and the receiver head 12 by optical communication, and data is transmitted between the receiver head 12 and the interface board 13 by a communication cable.

These touch probes 11, receiver head 1
The specific circuit configurations of 2 and the interface board 13 will be described next.

FIG. 3 is a block diagram showing the circuit configuration of the touch probe 11. In the figure, A is a power ON receiver, B is a modulated light transmitter, and 15, 15...
1 is the light receiving element consisting of a photodiode or the like;
6 is the power supply battery made of a lithium battery or the like; 17
18 is a bandpass filter for noise removal, and 18 is a low power amplifier with two operating modes: a normal mode with a high amplification factor and a low power consumption mode with a low amplification factor.
19 is ON only when a predetermined frequency signal is input
The detection circuit 20 generates an output, and the detection circuit 19 is
When an ON output is generated, the power supply ON circuit supplies the power supply 16 to the modulated high transmitter B and at the same time supplies a signal (voltage) for operating the low power amplifier 18 in the normal mode.

21 is a touch signal switch, which is connected to the main body 11b.
By pressure on the stylus 11c built into the
ON works. 22 is a resistor that supplies bias voltage to the touch signal switch, and 23 is a predetermined frequency.
24 is a programmable frequency divider that divides the output of the oscillation circuit 23 into 1/n ₁ or 1/n depending on ON/OFF of the touch signal switch.
Divide the frequency with a division ratio of n ₂ and output it. A power amplifier 25 amplifies and outputs the frequency-divided output. 1
4, 14... are the light projecting elements made of LEDs.

FIG. 4 shows the circuit configuration of the receiver head 12 and the interface circuit, where C is the light emitting circuit of the receiver head, D is the light receiving circuit of the receiver head, E is the operation command circuit of the interface circuit,
F is a light reception signal processing circuit of the interface circuit.

To explain the light emitting circuit C of the receiver head, 26 is the light emitting element made of an infrared light emitting diode (LED), etc., 27 is an oscillation circuit that can be switched between high output mode and low output mode, and 28 is an interface circuit. This is a differentiating circuit that detects the starting point of the operation command signal and supplies it to the oscillation circuit 27.

To explain the light receiving circuit D of the receiver head, 29 is the light receiving element made of a photodiode or the like, 30 is a band pass filter for removing noise, and 31 is an amplifier.

To explain the operation command circuit E of the interface circuit, 32 is an operation command contact such as a relay contact, and 33 is a photocoupler.

To explain the received light signal processing circuit F of the interface circuit, 34 is a limit amplifier that limits and amplifies the maximum output level, 35 is a PLL type FM detection circuit, and the received signal is processed at two predefined frequencies. A carry signal is generated when one of these frequencies is present, and when this received signal is one of these frequencies, for example a high frequency, the touch is ON.
Generate a signal. 36 is an output circuit that amplifies and outputs the touch ON signal and the carry signal.

Next, the operation of the optical transmission type touch probe device 10 of the present invention having the above configuration will be explained.

When the touch probe 11 is held in the chuck of a machine tool or the like and the touch probe starts to be used, the operation command contact 32 of the interface circuit 13 becomes conductive in response to a signal from a controller such as an NC control device. This conduction is sent by the photocoupler 33 to the light projecting circuit C of the receiver head 12 as a ground level signal A through the communication cable. While this signal is present, the oscillation circuit 2
Reference numeral 7 supplies a light projection current of a predetermined frequency to the light projection element 26, and the light projection element 26 irradiates the touch probe 11 with modulated light for operation command. Here, the fall of the signal A is detected by the differentiating circuit 28 and given to the oscillation circuit 27, so the output B of the oscillation circuit is at a high output level only for a short period of time at the beginning of the output.
After that, the output level returns to normal. Note that this high level only needs to correspond to the instantaneous rating of the light emitting element, so that at the initial stage of light projection, the light projecting element 26 can emit strong light.

The light emitted from the light projecting element 26 is directed toward the touch probe. A number of light receiving elements 15, 15... are distributed around the outer circumference of the touch probe 11, so no matter which direction the touch probe 11 is gripping the chuck, one or more of them You can receive this. The output of this light receiving element 15 is input to a low power amplifier 18 through a band pass filter 17. The low power amplifier 18 normally operates in a standby mode with extremely low power consumption, but the modulated light for startup from the receiver head 12 is initially quite strong as described above.
An output of sufficient level is given to the detection circuit 19. The detection circuit 19 detects this output, checks that it matches the frequency of the starting modulated light from the receiver head 12 and is not caused by other noise sources, and outputs it to the power ON circuit 20. power supply
When the ON circuit 20 receives this output signal, the power supply 1
6 into the modulated light transmitter B, and at the same time, a switching signal for operating the low power amplifier 18 in a normal mode with a high amplification factor is supplied.

Therefore, even if the modulated light for operation command from the receiver head becomes weak, the power supply is
The above power ON operation of the ON circuit 20 can be continued.

Modulated light transmitter B starts transmitting operation upon receiving power supply 16 . The oscillation circuit 23 has a predetermined frequency.
Oscillation starts at o, and this output is supplied to the programmable frequency divider 24. When the workpiece mounting table of the machine tool is moved by the NC control device, the workpiece may or may not come into contact with the tip of the stylus 11C of the touch probe.

When the workpiece comes into contact with the stylus 11c, the touch signal switch 21 becomes conductive, so that an "L" level signal is input to the programmable frequency divider 24.
If no touch is made, the touch signal switch 21 becomes non-conductive, and an "H" level signal is input to the programmable frequency divider 24.

In response to this, the programmable frequency divider 24
When receiving an “L” level signal, with a division ratio of 1/n ₁ ,
When receiving an "H" level signal, the oscillation output of frequency o is divided at a division ratio of 1/ _n2 . This frequency-divided output is amplified by the power amplifier 25,
A light projection current having a frequency of o/n or o/n ₂ is conducted to the plurality of light projection elements 14, 14, . . . . The light is then projected around the touch probe 11 at an angle of 360°.

This touch ON/OFF modulated light is received by the light receiving element 29 of the receiver head 12, and the received light output is passed through the bandpass filter 30 to the amplifier 3.
It is amplified by 1. Then, it is further sent to the interface board 13 through the communication cable, where the level is adjusted by the limiter amplifier 34.
The signal is detected by a PLL type FM detection circuit 35. This detection output generates a carry signal C indicating that reception is in progress when the modulation frequency of the received light signal is o/n ₁ or o/n ₂ , and furthermore, when this modulation frequency is o/n ₁
When this is the case, a touch ON signal (d) is also generated. These carry signals and touch ON
Signal D is amplified by the output circuit 36 and sent to a controller such as an NC control device.

As described above, the transmission/communication operation of the optical transmission type touch probe device 10 is performed, and desired measurements are performed.

When the touch probe 11 is no longer used, a controller such as an NC control device makes the operation command contact 32 of the interface circuit 13 non-conductive, so that the output transistor of the photocoupler 33 becomes non-conductive. Then, the signal A of the communication cable becomes "H" level, the output B of the oscillation circuit 27 disappears, and the modulated light for operation command is no longer projected from the receiver head 12 to the touch probe 11, so the power of the touch probe 11 is turned on. circuit 2
0 cuts off the power supply 16 to the modulated light transmitter B. After this, only the low power amplifier 18 operates in standby mode. In this state, power supply battery 1
Since only a very small current flows from the touch probe 6, and the consumption of the power supply battery is extremely low, the touch probe can be used repeatedly even if it is not used for a long time.

Effects of the invention According to the invention, the modulated light for operation command is emitted from the receiver head to the touch probe by an LED while the touch probe is in use. This increases the degree of freedom in installation, simplifies installation, and reduces costs.

In addition, since the touch probe has multiple light receiving elements distributed around its outer circumference, it is possible to receive modulated light for operation commands without being affected by the posture in which the touch probe is held in the chuck. During use, since the modulated light for operation commands is continuously projected, the configuration of the internal circuit of the touch probe can be simplified.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the external appearance of the device of the present invention, and FIG. 2 is a sectional view taken along line A-A in FIG. 1. 3 and 4 show the circuit configuration of one embodiment of the present invention, with FIG. 3 being a block diagram of the touch probe, and FIG. 4 being a block diagram of the receiver head and interface board. FIG. 5 is a perspective view showing an example of how the optical transmission type touch probe is attached to a machine tool. 10... Optical transmission touch probe device, 11...
...Touch probe, 11c...Stylus, 12
... Receiver head, 13 ... Interface board, 14 ... Light emitting element of touch probe, 1
5... Light receiving element of touch probe, 16... Power supply battery, 20... Power ON circuit, 21... Touch signal switch, 23... Oscillation circuit, 24... Programmable frequency divider, 26... Receiver head Light projecting element, 29... Light receiving element of the receiver head, A... Power ON receiving section, B... Modulated light transmitting section, C... Light projecting circuit of the receiver head, D...
Receiver head light receiving circuit.

Claims (1)

[Claim for Utility Model Registration] A built-in switch detects whether or not a stylus, which is detachably attached to the blade mounting position of a machine tool and protrudes from the tip, comes into contact with a workpiece, and this is sent as an optical signal to the outside. The touch probe is composed of a transmitting touch probe, and a receiver head that faces the touch probe and receives the optical signal emitted from the touch probe and converts it into an electrical signal. a plurality of light emitting elements and a plurality of light receiving elements; a light emitting circuit that changes the frequency of a light emitting current flowing through the plurality of light emitting elements depending on when a built-in switch is turned on and off; When at least one of the light-receiving elements receives modulated light for operation commands from the receiver head, the light-emitting circuit is provided with a light-receiving circuit that turns on power for driving the light-emitting circuit; a light emitting element, a light emitting circuit that supplies a light emitting current at a predetermined modulation frequency to the light emitting element for operation commands only while the touch probe is in use, a light receiving element for receiving, and an output of the light receiving element. A light receiving circuit is provided which processes the received frequency, determines whether it is a high frequency or a low frequency, and generates a carry signal indicating that reception is in progress and a touch output signal indicating that an ON signal is being input. An optical transmission touch probe device characterized by: