JPH02130401A - Touch sensor - Google Patents

Abstract

PURPOSE:To perform a measurement very simply and accurately by opening a first shut-off switch normally open when a contact probe is caused to be displaced with respect to a neutral position thereof. CONSTITUTION:When a spindle base 14 is fed finely to bring a spherical head 7a of a probe 7 into contact with work at a specified position, with the movement of a sensor body 1, the probe 7 is pressed with the work in an opposite direction to the movement of the spindle base 14. With the pressing thereof, the probe 7 is oscillated centered on a spherical body 35 or retracted axially, which causes a flange 7a to tilt or to move in a direction of separating from a base plate 23, in stead of having forced three protruding elements 24a, 24b and 24c as switching members on the side of the probe to press in contact with pins 26a, 26b and 26c as switching members on the side of a head cap. As a result, when any one or all of the three protruding elements 24a, 24b and 24c are separated from the pins 26a, 26b and 26c to open a first shut-off switch 10.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a touch sensor, which is attached to the main shaft of a machine tool or the main body of a special machine to center the workpiece or measure the machining dimensions. The present invention relates to a touch sensor used as a measuring device.

(Prior art and its problems) This type of touch sensor is normally attached to the machine spindle etc. by an automatic tool changer when necessary, and when measurement is completed, it is removed from the machine spindle etc. by the automatic tool changer and the machine is replaced. It is generally stored in a tool magazine.

However, in order to extract the electrical signal from the touch sensor during measurement, conventionally, as disclosed in Japanese Patent Publication No. 633242, the electric circuit on the touch sensor side and the electric circuit on the machine body side are connected using an electromagnetic coupler. Through this electromagnetic coupler, the electrical signal from the touch sensor is transmitted to the machine body and taken out. In addition to the signal transmission method using such an electromagnetic coupler, methods using radio waves and signal transmission methods using infrared rays have also been conventionally employed.

However, according to the above-described conventional technology, there are problems in that it is necessary to provide a power source such as a battery within the sensor body, and the configuration of the electric circuit becomes extremely complicated.

The present invention aims to solve this problem.

(Means for solving the problems) The touch sensor of the present invention that can solve the above problems has the following features:
The sensor body is detachably attached to the machine body, and the contact probe is three-dimensionally displaceable and protrudes from the tip head of the sensor body, and is normally biased to a neutral position by neutral position holding means. and when the contact probe is displaced in either direction from the neutral position, a first opening/closing switch consisting of a switch member provided on the contact probe side and a switch member provided on the head side of the sensor body is opened. It has a contact probe that is shaped like this, an arm that protrudes from the side surface of the sensor body, and a mounting block that is provided at a position that can face the tip of the arm on the machine body, and the arm and the mounting block are The opposite end has a second part that can be elastically contacted and closed when the sensor body is attached to the machine body.
The switch members for configuring the open/close switch are installed respectively, the switch member on the arm side is electrically connected to the sensor body via the first open/close switch, and the switch member on the mounting block side is connected to the machine body via the power supply. It is characterized by being electrically connected.

(Example) An example will be described with reference to the drawings. In Fig. 1, 1 is a sensor body integrally formed of a metal conductor such as steel, which is detachably fitted into a tapered hole 2a of a main shaft 2 in a machining center. a tapered shank portion 3;
It consists of a cylindrical body part 5 coaxially protruding toward the opposite side of the taper shank part 3 with the manipulator grip part 4 in between, and a head camp formed of an insulator such as plastic at the tip of the body part 5. 6 is removably attached. Reference numeral 7 denotes a three-dimensionally displaceable metal contact probe that penetrates the center opening 8 of the head cap 6, which is the tip head portion of the sensor body 1, and protrudes forward of the head cap 6, and is normally held in a neutral position by means 9. When the contact probe 7 is displaced in any direction from the neutral position, there is a gap between the contact probe 7 side and the herad cap 6 side. The interposed first opening/closing switch 10 is opened.

11 is an L-shaped hollow arm that integrally projects from the outer peripheral surface of the cylindrical body 5 of the sensor body 1; 12 is a conductive headstock that rotatably supports the main shaft 2 via a bearing 13; A mounting block is mounted on the front end surface of the arm 14 at a position facing the tip of the arm 11, and the arm 11 and the mounting block 12 are each made of an insulator such as plastic. Reference numeral 15 denotes a second open/close switch interposed between the arm 11 and the mounting block 12, and a conductive contact pin 1 serves as an arm-side switch member.
5a, and a conductive contact plate 15b as a switch member on the mounting block side, and the contact pin 15a is slidably supported within the tip of the arm 11, and the base end of this pin 15a is normally supported. The arm 11 is urged to protrude from the distal end surface by a conductive compression coil spring 16 coupled to the contact plate t, and when the sensor body 1 is attached to the main shaft 2, the contact pin 15a is in elastic contact with the contact plate t.
By being pressed against sb, the second open/close switch 15 is closed. The contact pin 15a, which is the arm-side switch member, is electrically connected to the first open/close switch 10 via the coil spring 16, the conductive coil spring mounting plate 17, and the conductor vA18. is connected to the body 5 of the sensor main body 1 via a conductive wire 19, while the contact plate 15b, which is a switch member on the mounting block side, is connected to the body 5 of the sensor body 1 through a conductive wire 19.
It is electrically connected to the headstock 14 by a conductive wire 22 passing through the a20 and a detection section 21 such as an indicator lamp. Therefore, when this touch sensor is attached to the main shaft 2, as shown in FIG.
A closed circuit is constituted by the detection unit 21, the power supply 20, the headstock 14, the bearing 13, and the main shaft 2.

A spherical head 7a is provided at the tip of the contact probe 7,
A flange portion 7b is provided at the base end located inside the head cap 6.
This flange portion 7b is disposed to face a donut-shaped base Fi, 23 made of an insulator that is removably fitted and fixed inside the head cap 6. As shown in FIG. 3, on the side of the contact probe flange portion 7b facing the base plate 23, there are three conductive protrusions 24a as contact probe side switch members of the first open/close switch 10.
, 24b, 24c are respectively attached at equal intervals in the circumferential direction via insulating members 25, while the base plate 23 has the protrusions 2
4a, 24b, 24c, conductive pins 26a, 26b as head cap side switch members,
26c are fixed through each other, and a stopper pin 28 is inserted into an elongated hole 27 provided in the flange portion 7b so that the correspondence relationship between them does not deviate. Further, as shown in FIG. 3, the protrusions 24a and 24b on the contact probe flange portion 7b are connected by a conductor 29, and the protrusion 24c is connected by a conductor 3.
0 is connected to the pin 26b on the base plate 23, and the base plate 23
The upper pin 26a is connected to the other end of a conducting wire 19 whose one end is connected to the body 5 of the sensor body 1, and the pin 26c is connected to the other end of a conducting wire 19 whose one end is connected to the arm-side switch member of the second open/close switch 15. The other end of 18 is connected. Therefore, when the contact probe 7 is in the neutral position, the protrusions 24a, 24b, 24C, which are switch members on the contact probe side, and the pins 26a, 26b, 26, which are switch members on the herad cap side,
c come into contact with each other as shown in FIG. 2, thereby closing the first open/close switch 10.

The neutral position holding means 9 includes a plunger 32 which is disposed coaxially with the contact probe 7 in the body 5 of the sensor body and supported movably in the axial direction by a slide ball bearing 31, and a plunger 32 which is disposed coaxially with the contact probe 7 in the sensor main body body 5 and which is supported by a slide ball bearing 31 so as to be movable in the axial direction. Taber recesses 33.3 formed in mutually opposite end surfaces of the jar 32
The steel sphere 35 fitted between the plunger 3 and the plunger 3
A compression coil is attached to an insulating mounting member 36 which is fitted into the inside of the body 5, has its tip end locked in the tip end of the plunger 32, and whose other end is attached to the center of the inner inner wall of the body part 5. The compression coil spring 37 connects the contact probe 7 via the plunger 32 and the sphere 35.
The contact probe 7 is held in a neutral position while being pressed forward. In addition, slide ball bearing 31
is supported by an insulating cylindrical support member 38 fitted within the body portion 5.

Further, a ring groove 39 is provided around the large-diameter end of the taper shank portion 3 of the sensor main body 1, and a gap between the ring groove 39 and the inner peripheral surface of the tapered hole portion 2a of the main shaft 2 is provided. An O-ring 40 as an air-tight ring for performing an air-tight seal is attached, and an annular groove 41 for receiving air that is sufficiently deeper and wider than the ring groove 39 is located at a position slightly away from the ring groove 39 toward the smaller diameter side. is provided around the annular groove 41, and an air passage portion 42a of a required length is provided from the bottom of the annular groove 41 along the axial direction of the sensor body 1, and the tip portion of the air passage portion 42a is bent into an L-shape. , is connected to an air passage section 42b extending through the arm 11 in its length direction, and the tip of this air passage section 42b is connected to the nozzle section 4.
2c, and is open at the distal end surface of the arm 11 so as to face the contact portion of the second open/close switch 15. this is,
The second open/close switch 15 is installed using cleaning air blown out from the taper hole of the spindle 2 for several seconds while changing tools in a machining center or the like with an automatic tool changer.
When attaching the sensor body 1 to the main shaft 2, the grip part 4 is grasped by a manipulator, and the taper shank part 3 is fitted into the tapered hole 2a of the main shaft 2. , air blown out from the inner depth of the tapered hole 2a is momentarily received in the annular groove 41, and this air flows from the annular groove 41 to the air passage 4.
Contact play 1 from the nozzle part 42c through 2a and 42b.
-15b and the tip of the contact bottle 15a that comes into contact with it, thereby removing deposits such as dust.

Note that 43 in FIG. 1 is a dust cover made of a flexible material.

Next, a case will be described in which, for example, the reference position of the main spindle 2 is measured using the touch sensor having the above-mentioned configuration. First, the sensor body 1 is attached to the main spindle 2 of the machining center, and the contact pin 15a at the tip of the arm 11 is attached. It presses against the contact plate 15b of the mounting block 12 of 14 examples of the headstock. At this time, the contact probe 7 is in the neutral position, the first opening/closing switch 10 is closed, and the second opening/closing switch 15 is also closed. Therefore, the electric circuit with the touch sensor attached is as shown in FIG. A closed circuit is constructed as shown in FIG. 2, and an indicator lamp is lit in the detection section 21.

Therefore, with the touch sensor attached as described above, the headstock 14 is finely fed to form the spherical head 7a of the contact probe τ.
When the contact probe 7 is brought into contact with a predetermined position of the workpiece, the headstock 14 moves after the contact, that is, the sensor body 1 moves, and the contact probe 7 is pressed by the workpiece in a direction opposite to the moving direction of the headstock 14. This pressure causes the contact probe 7 to become a sphere 35.
The three protrusions 24, which are the switch members on the contact probe side, swing around or move backward in the axial direction.
The flange portions 7a that had pressed the pins 26a, 26b, and 26c, which are the switch members on the head cap side, tilted or moved away from the base plate 23, and as a result, the three protrusions 24a, 24b,
Any one or all of pins 24c correspond to pins 26a.

When separated from 26b and 26c, the first open/close switch 10
is opened, and the indicator lamp of the detection unit 21 goes out. Since contact between the contact probe 7 and the workpiece can be detected by turning off the indicator lamp, the position of the reference point of the spindle 2 can be measured by reading the position of the spindle 2 at this time.

Note that a voltmeter or the like may be used in the detection section 21 instead of the display lamp.

(Effects of the Invention) According to the present invention, when a touch sensor is attached to a machine body such as a machine tool spindle, the touch sensor is composed of a machine body, a sensor body, a contact probe, a first opening/closing switch, a second opening/closing switch, and a power source. The electric circuit is configured to form a closed circuit, and the first open/close switch, which is always open, is opened when the contact probe is displaced from its neutral position. By detecting the moment when the open state changes to the open state using an indicator lamp, etc., measurement can be carried out extremely easily and reliably.However, there is no need to provide a power source to the sensor body, and the circuit configuration is as complicated as in the past. Maintenance is easy and costs can be significantly reduced as there is no need to use

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a touch sensor showing an embodiment of the present invention, Fig. 2 is an electric circuit diagram of the touch sensor attached to the main shaft of a machine tool, and Fig. 3 is a diagram showing how the first open/close switch is connected. FIG. 3 is an exploded perspective view showing the main parts of the provided contact probe and the head portion at the tip of the sensor body. DESCRIPTION OF SYMBOLS 1... Sensor book L 2... Main shaft of machining center, 3... Taper shank part, 6... Head cap, 7... Contact probe, 9... Neutral position holding means, 1
0...First opening/closing switch, 11...Arm, 12.
...Mounting block, 15...Second open/close switch, 20
...Power supply, 21...Detection unit, 40...O ring (
airtight ring), 41... annular groove for receiving air.

Claims (2)

[Claims] (1) A sensor body that is removably attached to the machine body, and a three-dimensionally displaceable contact probe that protrudes from the tip head of the sensor body, and is normally held in a neutral position by a neutral position holding means. When the contact probe is energized and displaced in any direction from the neutral position, a first open/close switch consisting of a switch member provided on the contact probe side and a switch member provided on the head side of the sensor body is activated. It has a contact probe that is designed to be opened, an arm that projects from the side surface of the sensor body, and a mounting block that is provided at a position that can face the tip of the arm on the machine body, and the arm A switch member for configuring a second opening/closing switch that can be closed by elastic contact when the sensor body is attached to the machine body is attached to the opposite end of the mounting block, and the switch member on the arm side is attached to the first switch member. It is electrically connected to the sensor body via an open/close switch,
A touch sensor characterized in that a switch member on the mounting block side is electrically connected to the machine body via a power source. (2) The sensor main body has a tapered shank part that is fitted into the tapered hole part of the machine main body, and an airtight ring is attached to the large diameter end on the outer peripheral surface of the tapered shank part, and this airtight ring An annular groove for receiving air is provided on the side with a smaller diameter than the mounting position, and an air passage is provided that passes from this annular groove through the inside of the sensor body, further through the inside of the arm, and opens at the tip of the arm. When the tapered shank part is fitted into the part, the air ejected from the inner part of the tapered hole part is received from the annular groove and is blown from the tip of the arm to the contact surface of the switch member of the second opening/closing switch through the air passage. The touch sensor according to claim 1, characterized in that: