JPH0151923B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a displacement measuring method and apparatus, and in particular, a method for measuring the shape of a three-dimensional object by arranging a large number of contact type linear displacement measuring machines (hereinafter referred to as contact type gauges) in parallel. The amount of relative displacement of the spindle from the reference position when the tip of the spindle is attached to the main body case so that it can freely move in the axial direction and has a protruding tip, which is suitable for use in various situations, comes into contact with the object to be measured. The present invention relates to an improvement in a displacement measuring method and device that detects the displacement and also regulates the stroke of the spindle using a damping means.

Conventionally, as a device for measuring the height or length of an object to be measured, as shown in FIGS. 1 and 2,
A main body case 12, and a spindle 1 which is attached to the main body case 12 so as to be movable in the axial direction and whose tip 14a protrudes, and which is displaced by contacting the object to be measured.
4, a tension spring 16 for urging the spindle 14 in the projecting direction (downward in FIG. 1) and applying a measuring force, a stopper 18 for regulating the stroke of the spindle 14, and the spindle 14. a detector 20 that detects the amount of displacement of the spindle 14 and outputs it as an electric signal; and a digital display 22 that displays the amount of relative displacement of the spindle 14 from the reference position based on the electric signal output from the detector 20. A so-called electric contact type gauge, which detects and displays the amount of relative displacement of the spindle 14 from a reference position when the tip of the spindle 14 contacts an object to be measured. 10 are known.

In this electric contact type gauge 10, the spindle 14 is used as the detector 20, for example.
A main scale 26 on which an optical grating is formed, which moves together with the spindle 14 and is attached to the
, an index scale 28 on which an optical grating is also formed, which is mounted at a position facing the main scale 26 on the body case 12 side via a substrate 27, and a light source ( (not shown), a photoelectric encoder consisting of a light receiving element 30 for detecting the brightness of the light transmitted through the main scale 26 and the index scale 28 is employed, and the photoelectric encoder detects: The amount of relative displacement of the spindle 14 from the reference position is digitally displayed, for example, on a digital display 22. Note that, normally, a zero clear circuit including a zero set switch 32 is provided so that the digital display 22 can display zero at the fixed position.

In the figure, 34 is a power switch, 36 is
AC power adapter used as needed, 3
Reference numeral 8 denotes a detent guide for vertically slidingly guiding the end of the lateral connecting member 40 connected to the spindle 14 on the side opposite to the spindle 14.

According to the above-mentioned contact type gauge 10, unless the power is cut off, the reference position set at an arbitrary position by pressing the zero set switch 32 is set to zero, and the amount of relative displacement from the reference position is set to zero. It has the feature that it is digitally displayed including the code.

On the other hand, in recent years, with the development of application technology for various types of measurements using the contact type gauges, as shown in FIG. Attempts have been made to compare and measure the shape of the three-dimensional object 54 placed thereon with a reference object. However, if the conventional contact type gauge is used as is, the detector and digital display will be cleared to zero when the power is turned off. Therefore, even if the reference body is placed on the surface plate 52 and the reference position is set, if the power to the contact type gauge 10 is cut off when replacing the reference body with the object to be measured, each displayed value will change. becomes zero, contact type gauge 10
It has been difficult to perform accurate comparative measurements because the reference position of

Particularly, when comparatively measuring a relatively large object to be measured with respect to a reference body, the power supply may be actively turned off at the time of loading/unloading in order to facilitate the loading/unloading of the measured object. There are also cases where the power must be turned off due to power outages, operational errors, measurements over two days, etc.

Note that the contact type gauge 10 usually includes a stopper 1 for regulating the stroke of the spindle 14.
8, it is conceivable to adopt a state in which the spindle 14 is at its maximum protrusion position (hereinafter referred to as a resting state) as the reference position. However, in general, whether the detector is a photoelectric encoder or another type, it is necessary to provide a buffer at the stroke end for accuracy and protection of the object to be measured. This buffer means utilizes a coil spring, a rubber cylinder, or the like. Therefore, the spindle 1 in the resting state
The reproducibility of the maximum protrusion position of No. 4 is poor, for example, it is not possible to obtain the reproducibility on the μm order required for a linear gauge, and therefore it is difficult to use a stationary state as a reference position.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional art, and is capable of reliably reproducing the reference position even if the power is actively or passively cut off. The object of the present invention is to provide a method and device for measuring displacement without any limitations.

The present invention detects the amount of relative displacement of the spindle from a reference position when the tip of the spindle, which is attached to a main body case so as to be movable in the axial direction and has a protruding tip, comes into contact with an object to be measured. In the displacement measuring method in which the stroke of the spindle is regulated using a buffer means, the above object is achieved by setting the spindle position immediately before the buffer means operates as the reference position.

The present invention also provides a main body case, a spindle that is attached to the main body case so as to be movable in the axial direction and whose tip protrudes, and is displaced by contacting the object to be measured, and a spindle that is biased in the projecting direction. a biasing means for applying a measuring force to the spindle; a buffer means for regulating the maximum protrusion position of the spindle; a detector for detecting the amount of displacement of the spindle and outputting it as an electric signal; A displacement measuring device comprising: a display device that displays the amount of relative displacement of the spindle from a reference position based on an electric signal output from a detector; The above object is achieved by providing a reference position detecting means and setting the spindle position when the reference position detecting means is activated as the reference position.

Furthermore, the reference position detection means is connected to a leaf spring attached to the main body case and an electrode piece which is also attached to the main body case and is in contact with the leaf spring when the spindle is not near the maximum protrusion position. ,
An engaging piece is attached to the spindle and is configured to break contact between the leaf spring and the electrode piece at a position immediately before the spindle comes into contact with the buffer means, so that the reference position can be easily detected. This is what I did.

In addition, the thickness of the leaf spring is different between the support part and the tip part, and the plate thickness of the tip part is made larger than the plate thickness of the support part, so that the reference position can be set with high precision without hindering the movement of the spindle. It is designed to be detectable.

Further, the position of the electrode piece can be adjusted in the axial direction of the spindle, so that the reference position can be adjusted.

Further, the buffering means is a cantilever-shaped thin piece made of an elastic member fixed to the main body case, so that high buffering performance can be obtained with a simple structure without impairing the effective stroke of the spindle. It is something.

Embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in FIGS. 4 to 7, this embodiment includes a main body case 12, and is attached to the main body case 12 so as to be movable in the axial direction and with the tip 14a protruding.
Spindle 14 that is displaced by contacting the object to be measured
, a tension spring 16 that is stretched between approximately the center of the spindle 14 and the main body case 12 and applies a measuring force by urging the spindle 14 in the protruding direction; and a maximum protrusion position of the spindle 14. (lower limit position in the figure) and a lower cushion stopper 60 that also serves as a buffer means to regulate the maximum retracted position (upper limit position in the figure) of the spindle 22. An upper cushion stopper 62, a main scale 26 attached to the spindle 14 for detecting the amount of displacement of the spindle 14 and outputting it as an electric signal, and an index attached to the main body case 12 side. Tux scale 28, light source (not shown)
and a detector 20 consisting of a photoelectric encoder including a light receiving element 30, and a digital display (not shown) for displaying the amount of relative displacement of the spindle 14 from the reference position based on the electrical signal output from the detector 20. The contact type gauge 10 has a reference position detector 64 for detecting the spindle position immediately before the spindle 14 contacts the lower cushion stopper 60, and the reference position detector 64 is activated. The spindle position at that time is set as the reference position.

The reference position detector 64 is fixed by a screw 66.
A leaf spring 70 (the fourth leaf spring 70 whose one end (the left end in FIG. 4) is attached to the main body case 12 side is inserted through the board 68
, and FIG. 6), and when the spindle 14, which is also attached to the main body case 12 side via the insulating bushing 72 and the board 68, is not near the maximum protrusion position (the leaf spring 70 shown by the broken line in FIG. is substantially straight), a pair of cylindrical electrode pieces 74 and 76 (see FIG. 4) are in contact with the tip of the leaf spring 70, and a pair of cylindrical electrode pieces 74 and 76 (see FIG. 4) are attached to the spindle 14 side.
At a position immediately before the spindle 14 contacts the lower cushion stopper 60 (when the right end of the leaf spring 70 shown in solid lines in FIGS. 4 and 7 is pushed downward), the leaf spring 70 and the electrode A substantially inverted L-shaped engagement piece 78 (fourth
(see Fig. 7).

The plate spring 70 has different thicknesses at the support portion and the tip portion, and the plate thickness at the tip portion is larger than the thickness at the support portion, so the engagement piece 78 allows the electrode pieces 74, The reproducibility of the position where contact with 76 is broken is very good.

Further, the positions of the electrode pieces 74 and 76 can be adjusted in the axial direction of the spindle 14, so that the reference position can be easily adjusted.

The cushion stoppers 60 and 62 each have one arm fixed to the main body case 12.
It is made of an elastic member, for example, a cantilever-like thin piece made of rubber. Therefore, a good damping effect can be obtained without substantially impairing the effective stroke of the spindle 14.

In the figure, 80 is a circuit board on which various electric circuits are arranged.

The action will be explained below.

As shown in FIG. The body is placed on the body, and the amount of displacement of the spindle 14 at that time is read from the digital display 22. At this time, if the power of each contact type gauge 10 is turned on before placing the reference body on the surface plate 52, the spindle 14 of each contact type gauge 10 is at its maximum protrusion position. For,
The reference position detector 64 will definitely operate.
Therefore, the dimensions of the reference body are measured based on the absolute reference position detected by the reference position detector 64.

Next, with the power turned off, the contact type gauge 12 is removed together with the frame 50 from the surface plate 52, and the object to be measured is placed on the surface plate 52. Furthermore, if the power to each contact type gauge 10 is turned on again before returning the frame 50 onto the surface plate 52, the spindle 14 of each contact type gauge 10 is at its maximum protrusion position at this time as well. , spindle 14
The reference position detector 64 always operates with the retracting operation, and the contact type gauge 10 measures the amount of displacement based on the absolute reference position. Therefore, even if the power to the contact type gauge is cut off when transporting the object to be measured or the contact type gauge, or even if the power is cut off due to a power outage, operational error, etc., the same absolute reference position will be maintained. Based on this, it becomes possible to perform accurate comparative measurements.

In this example, the reference position detector is provided near the maximum protrusion position of the spindle, so when the contact type gauge is not in the measurement state, the displayed value is always calibrated at the absolute reference position. Therefore, calibration using the reference position is reliably performed. Note that the method of obtaining the reference position is not limited to this, for example,
Of course, it is also possible to provide a reference position detector near the maximum retracted position or near the center of the spindle to set it as the reference position.

Furthermore, in this embodiment, a mechanical reference position detector composed of a leaf spring, an electrode piece, an engagement piece, etc. is used as the reference position detection means.
The configuration is simple and the burden on the electric circuit is small.
Note that the configuration of the reference position detection means is not limited to this. For example, a random pattern of scale stripes for detecting the absolute reference position is provided in the middle of the main scale, and the reference position is detected using the scale stripes. It is also possible to do so.

In the embodiments described above, the present invention was applied to a contact-type linear displacement measuring machine that includes a detector having a photoelectric encoder, but the scope of the present invention is not limited to this, and is applicable to devices other than photoelectric encoders. The present invention is similarly applicable to encoders including, for example, magnetic encoders, and displacement measuring devices other than linear displacement measuring devices. Furthermore, in addition to digital display, the present invention can be similarly applied to displaying measurement results using a printer or the like.

As explained above, according to the present invention, the reference position can be reliably reproduced even if the power is cut off, and the effective stroke of the spindle is hardly limited, which is an excellent effect. .

[Brief explanation of drawings]

Figure 1 is a front view showing a conventional contact type linear displacement measuring device, Figure 2 is an enlarged front sectional view, and Figure 3 is a three-dimensional object using a large number of contact type linear displacement measuring devices arranged in parallel. FIG. 4 is a front sectional view showing an embodiment of the displacement measuring device according to the present invention, FIG. 5 is a side sectional view, and FIG. The sectional view taken along the - line in Figure 4 and Figure 7 are as follows:
FIG. 4 is a sectional view taken along the line - in FIG. 4; 10... Contact type linear displacement measuring device, 12... Main body case, 14... Spindle, 16... Tension spring, 20... Detector, 60... Cushion stopper, 64... Reference position detector, 70...plate spring,
74, 76...electrode piece, 78...engaging piece.

Claims (1)

[Claims] 1. Detecting the amount of relative displacement of the spindle from a reference position when the tip of a spindle attached to the main body case so as to be movable in the axial direction and with the tip protruding comes into contact with an object to be measured. In addition, in the displacement measuring method in which the stroke of the spindle is regulated using a buffer means, a position of the spindle immediately before the buffer means operates is set as the reference position. Method. 2. A main body case, a spindle which is attached to the main body case so as to be movable in the axial direction and whose tip protrudes and is displaced by coming into contact with the object to be measured, and a measuring force is applied by urging the spindle in the protruding direction. a biasing means for regulating the maximum protrusion position of the spindle; a detector for detecting the amount of displacement of the spindle and outputting it as an electrical signal; A displacement measuring device having a display that displays the amount of relative displacement of the spindle from a reference position based on a signal, further comprising reference position detection means for detecting a spindle position immediately before the spindle contacts the buffer means. A displacement measuring device characterized in that the spindle position when the reference position detecting means is activated is set as the reference position. 3. The reference position detection means includes a leaf spring attached to the main body case, and an electrode piece that is also attached to the main body case and is in contact with the leaf spring when the spindle is not near the maximum protrusion position; Claim 2, further comprising an engaging piece attached to the spindle for breaking contact between the leaf spring and the electrode piece at a position immediately before the spindle contacts the buffer means. displacement measuring device. 4. The displacement measuring device according to claim 3, wherein the thickness of the leaf spring is different between the support portion and the tip portion, and the thickness of the tip portion is greater than the thickness of the support portion. . 5. The displacement measuring device according to claim 3, wherein the position of the electrode piece is adjustable in the axial direction of the spindle. 6. The buffer means is fixed to the main body case,
The displacement measuring device according to claim 2, which is a cantilever-like thin piece made of an elastic member.