JPH0443764Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a measuring touch sensor used in various machine tools.

(Technical background) Conventionally, for example, a touch sensor for measurement was attached coaxially to the main axis of an NC (numerical control) machine tool, etc.
While moving the NC workpiece table, the tip of the touch sensor is brought into contact with the surface of the workpiece fixed on the table, and this contact is detected by electrical means, for example, the center of the main shaft of the machine tool is connected to the surface of the workpiece. It is known to measure dimensions such as the distance between reference plane parts of a body and the intervals between parts of a workpiece.

An example of the above-mentioned prior art is a measuring touch sensor disclosed in Utility Application No. 172545/1983 (filed on November 7, 1988) by the applicant of the present invention.
This prior art will be explained with reference to FIGS. 1 and 2.

In FIGS. 1 and 2, 11 is a workpiece table, 12 is a support arm, and 13 is a machine tool main body. A metal workpiece W is placed and fixed on the workpiece table 11. The table 11 is movable in the horizontal direction (X, Y direction) and vertical direction (Z direction). Tool spindle 15 of machine main body 13
Additionally, the touch sensor 16 can be attached and detached coaxially using a method similar to a known tool attachment method.

The touch sensor 16 has a metal cylindrical centering bar 17, as shown in FIG. An annular seat 24 is formed to support the in place. A battery 22 is disposed inside the handle member 18, and the inner bottom surface of the handle member 18 is electrically connected to one electrode, for example, a cathode, of the battery 22. A conductive coil spring 25 is installed in the inner space of the cylindrical body portion of the centering bar 17, and a conductive spherical measuring element 19, such as a steel ball, is connected to one end of the coil spring 25. While the spring force of the coil spring 25 allows the coil spring 25 to be returned to a predetermined position on the annular seat 24 at the tip, the other end of the coil spring 25 is mechanically connected to the other positive electrode of the battery 22 via the indicator light 21. and electrically connected. As shown in FIG. 2, the indicator light 21 is disposed in the inner space of the body of the centering bar 17 at the center thereof, and a transparent insulating resin material is placed in the centering bar 17 at a position corresponding to the indicator light 21. An insulator member 20 which also serves as a see-through window and is formed by using an adhesive is interposed. In this way, the probe 19 seated on the tip of the centering bar 17 is
An insulator member 20 interposed approximately in the middle provides electrical insulation from the positive electrode of the battery 22, and the battery 22, indicator lamp 21, coil spring 25, and spherical probe 19 are connected in series.

As shown in FIG. 1, the touch sensor 16 is coaxially attached to a tool spindle 15 of a machine tool, for example, a drilling machine, and a metal workpiece W is fixed to the movable table 11. Next, the tool spindle 15 is lowered while moving the table 11,
When the spherical probe 19 at the tip of the touch sensor 16 comes into contact with the measurement surface of the workpiece W, the anode of the battery 22, the indicator light 21, the coil spring 25, the probe 19,
Workpiece W, machine tool arm 12, machine tool main body 1
3. An electrical closed circuit is formed between the handle member 18 and the cathode of the battery 22. At this time, the indicator light 21 lights up to indicate that the contact point 19 has come into contact with the workpiece W to be measured in shape and dimension through the window section 20, and is fixed to the tool spindle 15 by a known method by a calculation device (not shown). The position coordinates X, Y, Z of the touch sensor 16 are calculated.

According to the above-mentioned prior art, since the measuring element 19 is made into a sphere and is biased by the spring force of the coil spring 25 so as to come into close contact with the annular seat part 24, when measuring, even if the workpiece W Even if overtravel of the contact point 19 occurs, it can be smoothly absorbed by the coil spring 25, effectively preventing damage to the contact part of the touch sensor, and making it possible to measure at the appropriate contact position, resulting in high precision. It has the advantage of being able to perform measurements using

However, in the touch sensor of the above type, since the centering bar 17 is formed with the insulator member 20 interposed in the body portion approximately in the center, when it comes into contact with the workpiece W to be measured, the touch sensor moves in the lateral direction. The force applied to the centering bar 17 from the moving workpiece W is applied to the insulator member 2 at approximately the center of the bar 17.
This has a serious drawback in that a large bending moment acts on the bonded portion of 0, and the bonded portion is easily damaged.

(Purpose of the present invention) The present invention was made in order to solve the problems with the above-mentioned type of measurement touch sensor.
It is an object of the present invention to provide a touch sensor that has sufficient resistance to bending moments that act during measurement without requiring special reinforcing members.

(Structure of the present invention) In order to achieve the above object, the present invention interposes an electrical insulator member at either one end or the tip of the centering bar member, and connects the spherical probe to the other end of the battery. It is electrically insulated from the electrodes, so that electricity flows from one electrode of the battery to the other electrode of the battery via the coil spring member, the spherical probe, the object to be measured, the machine tool main body, and the handle member. A closed circuit is formed to enable detection of contact between the probe and the object to be measured.

Hereinafter, the present invention will be explained with reference to the accompanying FIGS. 3 to 6 showing embodiments.

(First Embodiment) In FIGS. 3 and 4, parts equivalent to those of the measuring touch sensor shown in FIGS. 1 and 2 are given the same reference numerals, and their explanations will be omitted.

In FIG. 3, four window holes are formed on the circumferential surface of one end of the centering bar 17 at angular intervals of, for example, 90°.
30 will be provided. A signal light 21 is arranged at a position corresponding to the window hole 30 inside the centering bar 17.
A cylindrical transparent insulator member 32 is adhered to cover the outer peripheral surface of the base of the centering bar 17, and each window hole 30 is
is covered and sealed with the transparent insulator member 32.
One end of the cylindrical transparent insulator member 32 is fitted into a closed opening of one end of the hollow handle member 18, and the transparent insulator 32 and the handle member 18 are bonded together with an adhesive (not shown). A power source 22 using, for example, a dry battery is housed in the hollow handle member 18 . A support pedestal 24 is provided at the other end of the bar 17, and the spherical probe 19 is seated in contact with the support pedestal 24 via a coil spring 25 stretched within the centering bar 17. ing. Above power supply 22, indicator light 2
1. The coil spring 25 and the spherical probe 19 are electrically connected in series. As shown in FIG. 4, from the circumferential surface of the measurement touch sensor formed in this way, the blinking of the indicator light 21 arranged in the bar 17 is observed through the transparent insulator member 32 and the window hole 30. can do.

In the touch sensor configured as described above, even if a lateral force is applied to the tip of the centering bar 17 from the moving workpiece W during measurement, the transparent insulator member 32 will not move the base of the centering bar 17 and the handle member 18. Since it is sandwiched between the transparent insulator members 32, only compressive stress acts on the transparent insulator member 32, and the bending stress is extremely small. Therefore, it is possible to reliably avoid damage to the attachment portion of the transparent insulator member 32, which has the same strength as a metal material against compressive stress.

(Second Embodiment) In the present invention, an insulator for electrically floating the probe 19 from one electrode of the battery 22 to form an electric circuit for detecting the time of contact is shown in FIGS. 3 and 4.
The tip of the centering bar 17 is not limited to the one that is sandwiched between the centering bar 17 and the handle member 18 as in the first embodiment shown in the figure, but as shown in FIG.
Insulator member 4 integrally formed with annular pedestal portion 42
0 may be formed by adhering.

(Third Embodiment) As shown in FIG. 6, a support pedestal member 43 having an annular seat portion 42 for supporting a spherical probe is made of steel and hardened. A cylindrical insulator member 44 is interposed between the support base member 43 and the centering bar 17. The insulator member 44 has an inward flange portion 44a and an outward flange portion 44b at both ends. The insulator member 44 and the support pedestal member 43 are bonded together using a fitting method or, for example, using a synthetic resin adhesive.

In the embodiment with the above configuration, since the insulator member 44 is interposed at the other end of the centering bar 17, it is possible to prevent the workpiece W from moving laterally during measurement, as in the first embodiment. The force applied to the touch sensor 16 acts exclusively as compressive stress, and the bending stress is made very small, so that damage to the insulator 44 portion can be reliably avoided. Additionally, the support pedestal can be made very sturdy.

(Operations and Effects of the Invention) As is clear from the above explanation, the measurement touch sensor of the present invention connects the conductive probe to the battery in order to form an electric circuit for detecting the point of contact with the workpiece W to be measured. By placing the insulator member to be electrically suspended from one electrode at either one end or the tip of the centering bar, the force applied from the workpiece W moving laterally during measurement is exclusively compressive stress. As a result, damage to the insulator portion can be reliably avoided without requiring any special protective member, and the insulator portion can be made to have excellent durability.

[Brief explanation of the drawing]

Figure 1 is a schematic side view of a machine tool with a conventional measuring touch sensor attached to the tool spindle, Figure 2 is a vertical cross-sectional view of the conventional measuring touch sensor shown in Figure 1, and Figure 3. 4 is a side view of the touch sensor of FIG. 3, and FIG. 5 is a longitudinal sectional view of the touch sensor of the second embodiment of the present invention. FIG. 6 is an enlarged partially cutaway sectional view of a touch sensor according to a third embodiment of the present invention. DESCRIPTION OF SYMBOLS 11... Workpiece table, 13... Machine tool body, 15... Tool spindle, 16... Touch sensor for measurement, 17... Centering bar, 18... Handle member, 19... Spherical measuring tip, 20 ...transparent insulator part (window), 21 ... indicator light, 22 ... power supply (battery), 24 ... annular seat, 30 ... window hole, 32 ...
... Transparent insulator member, 40 ... Insulator, 43 ... Support pedestal member, 44 ... Insulator member, W ... Workpiece (measurement object).

Claims (1)

[Claim for Utility Model Registration] A conductive cylindrical centering bar member that can be attached coaxially to the tool spindle of a machine tool, and a conductive handle member is attached to one end of the centering bar member. At the same time, a battery is disposed inside the handle member, an annular seat is formed at the other end of the centering bar, and a conductive coil spring member is installed inside the body of the centering bar member. One end of the coil spring member is connected to a conductive spherical measuring element, and the spherical measuring element is seated so as to be able to return to a predetermined position on the annular seat by the spring force of the spring member, and one of the batteries inside the handle member is connected to the conductive spherical measuring element. The object to be measured is constructed by electrically connecting an electrode, a coil spring, and a spherical gauge head in series, and the spherical gauge head attached to the tip of the centering bar member is fixed on a workpiece moving table of a machine tool. In a measurement touch sensor that electrically detects contact with the surface of an object and measures the shape and dimensions of the object to be measured, an electrical insulator member is attached to either one end or the tip of the centering bar member. The spherical gauge head is electrically insulated from the other electrode of the battery by intervening the coil spring member, the spherical gauge head, the object to be measured, the machine tool main body, and the handle member from one electrode of the battery. A measuring touch sensor, characterized in that an electrical closed circuit is formed that connects to the other electrode of the battery via the contact point, thereby making it possible to detect contact between the probe and the object to be measured.