JPH074489Y2 - Touch probe detection circuit - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a detection circuit of a touch probe, and more particularly to a detection circuit of a touch probe that is mounted on a coordinate measuring machine or the like and detects contact with an object to be measured. .

[Conventional technology]

Generally, a touch probe moves the touch probe, and when a contact of the touch probe comes into contact with an object to be measured and an external force acts on the contact, the support part (movable part) of the contact tilts by the external force, It is designed not to damage the contactor or the object to be measured. In many cases, the tilt of the movable member is used to detect the contact between the contactor and the object to be measured.

Conventionally, as this type of touch probe, a plurality of seating portions are used as electrical contacts, and when the movable member is positioned and supported by each seating portion, an electrical circuit in which the electrical contacts of each seating portion are connected in series is closed. Detecting the contact of the contact with the object to be measured by detecting when the movable member tilts to open at least one of the plurality of electric contacts, that is, when the electric circuit opens. There is.

FIG. 2 shows an example of a detection circuit of a conventional touch probe, and the touch probe 10 is electrically connected to the detection circuit via a connector 12.

The touch probe 10 is a probe contact as described above.
The probe contact J1 is opened when the contact of the touch probe 10 contacts the object to be measured. Further, the touch probe 10 is provided with an LED 10A for probe monitoring.

Now, when the touch probe 10 is connected to the connector 12 and the probe contact J1 is closed, the input terminal 14 of the power supply V _cc
Since a current flows from the transistor Q1 through the resistor R1 and the probe contact J1, the base current does not flow in the transistor Q1 and the transistor Q1 is turned off. This also turns off transistor Q2.
Then, the output voltage of the output terminal 16 becomes L level, and the probe monitor LED 10A connected to the output terminal 16 via the monitor LED drive circuit 18 is turned off.

On the other hand, in the above state, when the contact of the touch probe 10 contacts the object to be measured and the probe contact J1 is opened, the capacitor C is charged through the resistors R1 and R2, and then the current flows to the base of the transistor Q1 to cause the transistor Q1 to flow. Q1 turns on. That is, when the probe contact J1 is opened for a certain period of time (a predetermined CR time constant by the resistors R1, R2 and the capacitor C), the transistor Q1 turns on. As a result, the transistor Q2 also turns on, the detection signal (H level) is output from the output terminal 16, and the probe monitor LED 10A connected to the output terminal 16 via the monitor LED drive circuit 18 lights up. To do.

[Problems to be solved by the invention]

By the way, in the conventional detection circuit, when the touch probe 10 is not connected to the connector 12, a detection signal is output from the output terminal 16, so a short circuit is added to prevent the detection signal from being output. Or, it was designed to be switched by another switch.

The present invention has been made in view of the above circumstances, and provides a detection circuit of a touch probe that can prevent a detection signal from being automatically output when the touch probe is not connected to a connector. With the goal.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides a touch probe having a contact, a contact that is seated by the contact and is opened by a posture displacement caused by contact with a work, and a probe monitor light-emitting element. In a detection circuit of a touch probe having a connector that is freely connected and a detection circuit that outputs a detection signal from a measurement output terminal when the contact is opened, the detection signal of the detection circuit A drive circuit for supplying a current for turning on the light emitting element by an input to the light emitting element, and a drive circuit for determining whether the contact is open or the touch probe is not connected to the connector. It is electrically connected to the output side, and when the touch probe and the connector are connected, the brightness of the light emitting element can be adjusted to the light emitting element. First passing a small current that can not be
When it is detected that a minute current is flowing in the circuit and the first circuit and the contact between the work and the touch probe is detected by opening the contact, a detection signal is output from the measurement output terminal, and the first signal is output. When it is detected that a minute current does not flow in the first circuit, the second circuit is configured to prevent the detection signal from being output from the output terminal.

[Action]

According to the present invention, the touch probe is connected to the connector depending on whether or not the current flows by passing a current through the light emitting device for the probe monitor of the touch probe so that the brightness of the light emitting device is not visible. Whether or not it is detected by the detection means. And this detection means
When the touch probe is not connected to the connector,
The detection signal is not output.

〔Example〕

Hereinafter, a preferred embodiment of a detection circuit of a touch probe according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing an embodiment of a detection circuit of a touch probe according to the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals, and their details are omitted.

The detection circuit shown in FIG. 1 is the conventional detection circuit shown in FIG. 2, that is, a main circuit that obtains a predetermined detection signal by opening and closing the probe contact J1 and the main circuit when the touch probe 10 is not connected to the connector 12. And a control circuit for disabling.

That is, the control circuit includes a transistor Q3, resistors R3, R4, R
5. It consists of Zener diode ZD and line L. The transistor Q3 is disposed between the connection point A1 of the resistors R1 and R2 and the ground, and the resistors R3, R4,
Zener diode ZD and resistor R5 are input terminals for power supply V _cc 1
4 is connected in series, and the connection point A2 between the Zener diode ZD and the resistor R5 and the base of the transistor Q3 are connected in series. In addition, line L has resistors R3 and R4
It is wired between the connection point A3 and the monitor LED 10A.

In the detection circuit configured as described above, the case where the touch probe 10 is not connected to the connector 12 will be described first.

In this case, a base current flows to the base of the transistor Q3 from an input terminal 14 of the power supply V _cc through a resistor R3, R4 and Tsuenaidaodo ZD, the transistor Q3 is turned ON. As a result, the connection point A1 becomes the ground level regardless of whether the probe contact J1 is opened or closed, and the transistors Q1 and Q2 are
It turns off. Therefore, the output voltage of the output terminal 16 becomes L level.

Next, a case where the touch probe 10 is connected to the connector 12 will be described.

In this case, a current always flows from the input terminal 14 of the power supply _Vcc to the probe monitor LED 10A through the resistor R3 and the line L. Note that the resistance value of the resistor R3 is set to a large value, and the above current is suppressed so as to be a minute current (about 0.5 mA) such that the brightness of the LED 10A cannot be seen.

Further, the potential of the connection point A3 at this time is lower than the set voltage of the Zener diode ZD, and the base current does not flow in the base of the transistor Q3. That is,
When the touch probe 10 is connected to the connector 12, the base current does not flow in the base of the transistor Q3,
Transistor Q3 is off.

Here, if the probe contact J1 is closed,
The potential of A1 becomes the ground level, the base current does not flow in the base of the transistor Q1, and the transistor Q1 is turned off. As a result, the transistor Q2 also turns off and the output terminal 16
Voltage becomes L level.

On the other hand, when the contact of the touch probe 12 contacts the object to be measured and the probe contact J1 is opened for a predetermined time or more, a current flows from the input terminal 14 of the power supply _Vcc to the base of the transistor Q1 via the resistors R1 and R2, Transistor Q1 turns on. This allows
The transistor Q2 is also turned on, and the detection signal (H level) is output from the output terminal 16. Also, output terminal 16 and monitor LED
In the LED 10A for probe monitor connected via the drive circuit 18, a sufficient current flows so that the brightness of the LED 10A can be seen, and the LED 10A lights up.

[Effect of device]

As described above, according to the touch probe detection circuit of the present invention, it is possible to detect whether or not the touch probe is connected to the connector by adding a simple circuit. That is, a circuit for passing a minute current to the extent that the brightness of the light emitting element is not visible is added to the probe monitor light emitting element, and whether or not the touch probe is connected to the connector based on whether or not the minute current is flowing. Since the touch sensor is detected, the existing touch probe and connector can be used as they are. Also, if it is detected that the touch probe is not connected to the connector,
Since the detection circuit is automatically disabled, it is possible to eliminate the short circuit that was necessary in the past in order to disable the detection circuit. It is possible to save the troublesome work of switching with a switch.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a detection circuit of a touch probe according to the present invention, and FIG. 2 is a circuit diagram showing an example of a detection circuit of a conventional touch probe. 10 ... touch probe, 10A ... LED, 12 ... connector,
16 ... Output terminal, J1 ... Probe contact, Q1-Q3 ... Transistor, R1-R5 ... Resistor, C ... Capacitor, ZD ...
Zener diode.

Claims (1)

[Scope of utility model registration request] 1. A contact probe, a touch probe having each of a contact, a contact that is seated and opened by a posture displacement caused by contact with a workpiece, and a probe monitor light-emitting element, and a connector to which the touch probe is detachably connected. In a detection circuit of a touch probe having a detection circuit configured to output a detection signal from a measurement output terminal when the contact is opened, the light emitting element is activated by inputting the detection signal from the detection circuit. A drive circuit for supplying a current for lighting to the light emitting element, and an electrical connection to the output side of the drive circuit to determine whether the contact is open or the touch probe is not connected to the connector. It is so small that the brightness of the light emitting element cannot be seen by the light emitting element when the touch probe and the connector are connected. When detecting that a minute current is flowing in the first circuit for passing an electric current and the first circuit and detecting the contact between the work and the touch probe by opening the contact, a detection signal is output from the measurement output terminal. A detection circuit for a touch probe, comprising: a second circuit that outputs a signal and that prevents a detection signal from being output from the output terminal when it is detected that a minute current does not flow in the first circuit.