JPH06241794A - Bubble tube and tilt sensor using this bubble tube - Google Patents

Abstract

PURPOSE:To provide a small tilt sensor having high resolution, a wide measuring range, and high reliability by making the curvature of the surface kept in contact with bubbles large in radius at the center area and small at the periphery into a continuous nonspherical surface. CONSTITUTION:The nonspherical surface 11a of a recessed plate 11 has a large radius of curvature R1 at the center area A and a small radius of curvature R2 at the peripheral area to form the surface 11a having the continuous radius of curvature. The curvature of the surface 11a kept in contact with bubbles 15 is made a small radius R2 at the peripheral area of the upper face, and bubbles 15 are quickly moved to the area A from the wide measuring range (tilt state). In the area A having a large radius of curvature, i.e., in a narrow measuring range (nearly horizontal state), the shift quantity of bubbles 15 is small, and the leveling work with high resolution can be performed. The shift quantity of bubbles 15 is reduced as bubbles 15 are moved to the center of a tube, the tube can be largely moved for the measurement of a large angle, and the precision is increased near the horizon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bubble tube and a tilt sensor using the bubble tube, and more particularly to a bubble tube having a high accuracy and a wide measurement range, and a tilt sensor using the bubble tube.
For example, the present invention relates to a tilt sensor suitable for an automatic leveling device.

[0002]

2. Description of the Related Art Conventionally, a bubble tube for measuring a horizontal or inclination angle using a bubble is known. Generally, the curvature of the surface of the bubble tube which is in contact with the bubble is always constant, and the sensitivity of this bubble tube is expressed by the inclination angle required for the movement of the bubble.

For example, as shown in FIG. 10, when the bubble tube is tilted by an angle θ about a certain point C, if the bubble 101 moves relatively by a along a spherical surface 102 having a radius R, the distance a. = R · θ Then, the sensitivity of the bubble tube and the radius of the spherical surface 102 in contact with the bubble 101 are constant R (meter) ≅413 / θ · sec (the above a = 2 mm,
R = m, θ = second).

Generally, the tilt sensor 70 is a measuring device for detecting the horizontal or tilt angle, and is used for an automatic vertical correction sensor such as a theodolite, an automatic leveling sensor, etc. The structure thereof is shown in FIG. As described above, in general, the bubble tube K and the light transmitting unit 71 that irradiates the bubble tube K with light.
And light receiving elements 72, 72 for converting the light transmitted through the bubble tube K into an electric signal, and an arithmetic unit (not shown) connected to the light receiving element 72 and calculating an inclination angle based on the electric signal. Has been done.

The bubble tube K used here is a generally known bubble tube, and a concave plate 73 having a spherical surface in contact with the bubble 77 and a parallel glass plate 74 are joined by a bubble tube frame 75, It has a structure in which a liquid 76 and a bubble 77 are enclosed therein. The sensitivity of the bubble tube K directly affects the sensitivity of the tilt sensor 70. Incidentally, reference numeral 7 in FIG.
8 is a collimation lens.

[0006]

As described above, in the conventional bubble tube K, since the radius of curvature R of the surface in contact with the bubble 77 is constant, when the resolution of the bubble tube K is increased (that is, the surface is flattened). ), It is necessary to increase the curvature radius R1 as shown in FIG. 8. However, if the curvature radius R1 is increased in this way, the measurement range (measurement range) becomes narrower in the same shape (same curvature radius). There is.

Further, in order to widen the measurement range, the radius of curvature R2 is made small as shown in FIG. 9 (that is, the surface is curved).
If so, there is an inconvenience that the resolution is lowered. Therefore, it is difficult to provide a bubble tube having a wide measurement range and high resolution.

Also, regarding the tilt sensor, in order to widen the measurement range and increase the resolution, it is necessary to increase the shape of the bubble tube forming the tilt sensor or to electrically increase the resolution. As described above, in the conventional example, when the measurement range is wide and the resolution is high, it is necessary to increase the size of the tilt sensor to cope with the increase in the size of the tilt sensor and the space for arranging the tilt sensor. There were inconveniences such as complication of electric circuits.

An object of the present invention is to provide a bubble tube having a wide measuring range and high resolution.

Another object of the present invention is to provide a tilt sensor which has a high resolution in a horizontal portion and a wide measurement range, is small in size, has high reliability, and has a simple electric circuit.

[0011]

The invention according to claim 1 of the present application is a bubble tube K for detecting the horizontal or inclination angle from the position of the bubble.
In, the curvature of the surface of the bubble tube contacting the bubbles is made an aspherical surface having a continuous radius of curvature by increasing the radius of curvature in the central region and decreasing the radius of curvature in the peripheral region.

The invention of claim 2 of the present application relates to a tilt sensor, wherein the curvature of the surface of the bubble tube in contact with the bubbles is
A bubble tube having an aspherical surface having a continuous radius of curvature with a large radius of curvature in the central region and a small radius of curvature in the peripheral region; a light transmitting unit for irradiating light toward the bubble tube; It is provided with a light receiving element for converting the light transmitted through the tube into an electric signal, and a calculation section for calculating the inclination angle from the electric signal.

[0013]

According to the first aspect of the present invention, the curvature of the surface of the bubble tube in contact with the bubbles has a large radius of curvature in the central region and a small radius of curvature in the peripheral region, and is an aspherical surface having a continuous radius of curvature. Therefore, high resolution in the central area,
A wide measurement range can be secured in the peripheral area.

In the measurement, if the curvature of the surface of the bubble tube that comes into contact with the bubbles is constant, the leveling work is performed gradually so that the bubbles come to the center position when detecting the horizontal position. However, according to the bubble tube of the present invention, the radius of curvature is made small in the peripheral region, so that the bubble quickly moves from the wide measurement range (inclined state) to the central region. Then, in a measurement range having a large radius of curvature, that is, in a narrow measurement range (a substantially horizontal state), high-resolution leveling work can be performed.

According to the second aspect of the present invention, since the bubble tube is used, the resolution is high in the central region,
In the peripheral area, a tilt sensor having a wide measurement range can be used. Moreover, since it is not required that the size of the bubble tube K shape is large, the size is small, the reliability is high, and the electric resolution is high, the electric circuit is not complicated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The members, arrangements, and the like described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention. 1 to 3 show an embodiment of the present invention, FIG. 1 is an explanatory sectional view of a tilt sensor, FIG. 2 is an explanatory sectional view of an inclined tilt sensor, and FIG. 3 is a perspective view of a circular bubble tube.

The bubble tube K of this example is composed of a cylindrical so-called circular bubble tube, and a concave plate 11 having an aspherical surface 11a on its inner surface and a parallel glass plate 12 are joined by a bubble tube frame 13 to form a cylindrical shape. In the formed transparent container, the transparent liquid 14 and the bubbles 1
And 5 are enclosed. Then, the horizontal or tilt angle is detected from the position of the bubble 15.

The aspherical surface 11a of the concave plate 11 in this example.
Is an aspherical surface 11a having a continuous radius of curvature by increasing the radius of curvature R1 in the central region A and decreasing the radius of curvature R2 in the peripheral region B. In this example, the aspherical surface 11a
The radius of curvature of 2 is composed of two different radii R1 and R2, but three or more different radii may be composed of successively smaller radii from the central region.

The tilt sensor 21 of this embodiment is the bubble tube K.
And a light source forming the light transmitting unit 16, light receiving elements 18 and 19 forming a light receiving unit, and an arithmetic unit (not shown).

Below the bubble tube K, a light transmitting section 16 is arranged, and the light transmitting section 16 is a light emitting diode 16 which is a light source.
a, and the light emitting diode 16a includes a bubble tube K
The collimation lens 17 is used to irradiate the lower part of the laser light in parallel.

Above the bubble tube K, the light receiving elements 18 (18a, 18b) and 19 (19a, 19a, 19b, which are divided on both sides with the center as a boundary.
19b) is provided, and the light receiving elements 18 and 19 convert the light transmitted through the bubble tube K into an electric signal to detect the tilt angle.

In this example, as shown in FIG. 1 and FIG.
By attaching a pair of light receiving elements 18 and 19, it is possible to output tilt components in two directions, the X direction and the Y direction. The light receiving elements 18 and 19 are connected to a calculation unit (not shown).
The electric angle signal is received from and the tilt angle is calculated.

In order to convert the movement of the bubble 15 in the bubble tube K into an electric signal, the light emitted from the light emitting diode 16a is
The collimation lens 17 collimates the light and irradiates it from the lower portion of the bubble tube K to the light receiving elements 18 and 19 side.

The shadow of the bubble 15 is reflected by the light receiving elements 18, 19
2 sets of light receiving elements 18 (18a, 18b)
The position of the bubble 15 is converted into an electric signal from the difference between the outputs of 19 (19a, 19b). That is, when the tilt angle is converted into an electric signal by the tilt sensor 21 using the bubble tube K, the electric output of the angle is output as an exponential function of the angle as shown in FIG.

Next, the resolution of the tilt angle of the bubble tube K having the above-described structure and the tilt sensor 21 using this bubble tube K will be described with reference to FIGS. 4 and 5. As in the present example, the curvature of the surface 11a of the bubble tube K in contact with the bubble 15 is small in the peripheral region B (see FIG. 2) of the upper surface, so that the bubble 15 can be quickly moved from a wide measurement range (inclined state).
Moves to the central area A. And the radius of curvature is large,
That is, in the central region A, which is a narrow measurement range (substantially horizontal state), the movement amount of the bubbles 15 is small as shown in FIG. 1, and high-level leveling work can be performed.

That is, FIG. 5 is a graph showing the relationship between the amount of bubble movement and the inclination angle. As shown in FIG. 5, of the surface of the bubble tube K shown in FIG. In a spherical bubble tube K having a radius of curvature R2 (shown by a chain line γ), accuracy cannot be obtained unless the amount of movement of bubbles is smaller than 0.25 mm. The bubble tube K used can be configured so that the accuracy can be obtained from a moving amount of a little over 0.5 mm as shown by a solid line α.

As indicated by the solid line β, the curvature of the surface of the bubble tube shown in FIG. 8 in contact with the bubble has a radius R1 as shown by the solid line β.
The spherical bubble tube K has a diameter of 0.449 mm, which corresponds to a high resolution.

The output (y) of the inclination angle is an exponential function of the movement amount (x) of the bubble and can be expressed by the equation y = a (e ^bx -1). In this equation, y is the output of the tilt angle (seconds), x is the movement amount of the bubble (mm), and a is the radius of curvature R1.
Is an inclination angle at, and b is an inclination angle at a radius of curvature R2.

According to the tilt sensor 21 using the bubble tube K of the present invention as described above, as shown in the graph of bubble movement amount and tilt sensor inclination angle shown in FIG. Bubbles 15 as they move to the center of
Is configured to reduce the movement amount of the bubble tube, the bubble tube K can be moved largely for the measurement at a large angle, and the accuracy becomes higher as it approaches the horizontal direction. That is, a small amount of movement of bubbles can be achieved with high accuracy at an angle between 0 and a, and a measurement range similar to the radius R2 of the conventional example is provided between angles a and b. In addition, between the angles a and b, since the target measurement can be determined with the accuracy between 0 and a, there is no particular influence on the measurement accuracy. Therefore, when mounted on an automatic leveling device, it is possible to reduce the working time as a whole,
It is possible to improve work efficiency.

When the angle is small (horizontal part), the tilt sensor (having a large radius of curvature and high resolution in the range A of FIG. 2) exhibits the same characteristics. Can also be measured up to the angle b (range B in FIG. 2). Similarly, tilt sensor (curve radius is small and resolution is low in the range B of FIG. 2)
Can also measure up to the angle b.

There is no inconvenience that the movement amount of the bubble 15 is large and the output angle is narrow as in the tilt sensor corresponding to FIG. 8, that is, it is highly accurate but the measuring range is small.
Further, although the output range for measuring the output angle is large like the tilt sensor corresponding to FIG. 9, the inconvenience that the movement amount as a whole does not change even at an angular position where high accuracy is required can be solved.

FIG. 6 shows another example of the bubble tube according to the present invention, and is a perspective view showing an example of a rod-shaped bubble tube K in this example. Thus, in the case of measuring the inclination in one direction like the rod-shaped bubble tube K, the central area of the bubble tube K has a curvature close to a plane (that is, a curved surface with a large radius), and the distance from the central area increases. By making the cross section in the longitudinal direction, which is a surface having a large curvature (that is, a curved surface having a small radius), an aspherical surface, it is possible to achieve the same effect as that described for the circular bubble tube K.

[0033]

According to the first aspect of the present invention, the curvature of the surface of the bubble tube contacting the bubbles has a continuous radius of curvature by increasing the radius of curvature in the central region and decreasing the radius of curvature in the peripheral region. Since it is an aspherical surface, it is possible to obtain a bubble tube having a high resolution in the central region and a wide measurement range in the peripheral region and a high resolution in the horizontal portion and a wide measurement range. Therefore, according to the bubble tube of the present invention, since the radius of curvature is made small in the peripheral region, it is possible to speed up the measurement work by rapidly moving the bubble from the wide measurement range (inclined state) to the central region. In addition, it is possible to perform the leveling work with high resolution in the central region having a large radius of curvature, that is, a narrow measurement range (substantially horizontal state).

According to the second aspect of the invention, since the bubble tube is used, the resolution is high in the central region,
In the peripheral area, a tilt sensor having a wide measurement range can be used. Moreover, since the shape of the bubble tube is not enlarged, the size is small, the reliability is high, and the electric resolution is not high, a complicated electric circuit is not required.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of a tilt sensor.

FIG. 2 is an explanatory cross-sectional view of a tilt sensor that is tilted.

FIG. 3 is a perspective view of a circular vial.

FIG. 4 is a graph showing a bubble movement amount and a tilt angle of a tilt sensor.

FIG. 5 is a graph showing a relationship between a bubble movement amount and an inclination angle.

FIG. 6 is a perspective view showing an example of a rod-shaped bubble tube.

FIG. 7 is an explanatory sectional view of a conventional tilt sensor.

FIG. 8 is an explanatory cross-sectional view showing a state in which a conventional tilt sensor is tilted.

FIG. 9 is an explanatory cross-sectional view showing a state in which a conventional tilt sensor is tilted.

[Explanation of symbols]

 11 Concave Plate 11a Aspherical Surface 12 Parallel Glass Plate 13 Bubble Tube Frame 14 Transparent Liquid 15 Bubble 16 Light Transmitter 16a Light Emitting Diode 17 Collimation Lens 18, 19 Photoreceptor 21 Tilt Sensor A Center Region B Peripheral Region K Bubble Tube R1, R2 Curvature radius

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[Procedure amendment]

[Submission date] February 4, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 10

[Correction method] Added

[Correction content]

FIG. 10 is an explanatory diagram showing movement of bubbles when the bubble tube is tilted.

Claims (2)

[Claims] 1. In a bubble tube for detecting horizontal or inclination angle from the position of the bubble, the curvature of the surface of the bubble tube in contact with the bubble is
A bubble tube having an aspherical surface with a continuous radius of curvature with a large radius of curvature in the central region and a small radius of curvature in the peripheral region. 2. A bubble tube which is an aspherical surface having a continuous radius of curvature by increasing the radius of curvature in the central region and decreasing the radius of curvature in the peripheral region with respect to the curvature of the surface of the bubble tube in contact with the bubble, A tilt sensor comprising: a light transmitting unit for irradiating light toward a bubble tube; a light receiving element for converting light transmitted through the bubble tube into an electric signal; and a calculation unit for calculating an inclination angle based on the electric signal.