JP4975508B2 - Tilt angle detector - Google Patents

Description

  The present invention relates to a tilt angle detector that extracts a tilt angle as an electrical signal.

Surveying instruments used in surveying, civil engineering, construction, etc., ie automatic level and electronic level, equipped with a compensator (automatic tilt correction mechanism) that automatically corrects the collimation axis horizontally when tilted slightly. It has been. However, since this compensator has a tilt limit that can be corrected, an alarm is required when the automatic level and the electronic level exceed the range that can be corrected by the compensation center. For this purpose, a tilt angle detector that extracts the tilt angle as an electrical signal is required. The horizontal direction or horizontal plane refers to a direction or plane perpendicular to the direction of gravity.

  By the way, what is described in the following patent document 1 is known as an inclination angle detector provided in a surveying instrument and extracting the inclination angle of the surveying instrument as an electrical signal.

  An inclination angle detector described in Patent Document 1 shown below is shown in FIGS. FIG. 4 is a side view of the tilt angle detector. FIG. 5 is a plan view of the tilt angle detector. FIG. 6 is a diagram showing an output from a line sensor provided in the inclination angle detector.

  As shown in FIGS. 4 and 5, the inclination angle detector includes a bubble tube 11 in which a transparent liquid 14 and bubbles 15 are enclosed in a circular transparent container 13 having a curved upper inner surface 12. In order to take out the inclination angle as an electric signal, light is emitted from the light source 16 below the bubble tube 11, and this light is converted into parallel rays by the lens 17 to irradiate the bubble tube 11. The light transmitted through the bubble tube 11 is divided into two by the half mirror 18 arranged above the bubble tube 11. The light transmitted through the half mirror 18 is incident on the first line sensor 20 arranged along the X-axis direction (see FIG. 5) above the half mirror 18. The light reflected to the side by the half mirror 18 is incident on the second line sensor 21 disposed along the direction parallel to the Y axis (see FIG. 5) orthogonal to the X axis on the side of the half mirror 18. .

  An output signal as shown in FIG. 6 is obtained from the first line sensor 20 or the second line sensor 21. Light is mostly reflected near the periphery of the bubble 15 and light does not pass through the bubble tube 11, so that the line sensor output is substantially zero. From the position on the line sensor where the line sensor output is substantially zero, the position in the X-axis direction and the Y-axis direction of the center of the bubble 15 can be detected. When the tilt angle detector is tilted, the position of the bubble 15 is moved. In response, the position on the line sensor where the line sensor output is substantially 0 changes, and from this change in position, the X of the center position of the bubble 15 is changed. An axial displacement and a Y-axis displacement are obtained, and a tilt angle change of the tilt angle detector in the X-axis direction and the Y-axis direction can be detected from the displacement.

Japanese Patent No. 3072779

Recent surveying instruments are required to be highly accurate and low in price. Since the tilt angle detector disclosed in Patent Document 1 detects a tilt angle in two axial directions, two line sensors 20,
21 is used, and there is a problem that it tends to be expensive. In particular, when high accuracy is required and a line sensor having a high resolution is used, there is a problem that the two line sensors 20 and 21 are further expensive.

  Moreover, since the half mirror 18 and the line sensor 20 are arrange | positioned above the bubble tube 11, the inclination | tilt angle detector disclosed by the said patent document 1 is difficult to visually recognize the bubble 15 from upper direction, and is for visual recognition. It was necessary to provide a bubble tube for visual recognition separately. This was also the cause of the problem of expensive surveying instruments.

  The present invention has been made in view of the above problems, and in an inclination angle detector that extracts an inclination angle as an electrical signal, the inclination angle in two axial directions can be detected by one line sensor. It is an object of the present invention to realize a further price reduction of a surveying instrument by sharing two bubble tubes for an inclination angle detector and for viewing a horizontal plane.

In order to solve the above-described problem, an inclination angle detector according to a first aspect of the present invention includes a bubble tube, a single line sensor disposed on the same horizontal plane as the bubble tube, and the same horizontal plane as the bubble tube. Two light emitting means for projecting shadows of bubbles in the bubble tube to different positions of the line sensor, and light emitted from one of the two light emitting means is light after irradiating the bubble tube. The light is reflected by the reflector and reaches the line sensor, and the light emitted from the other of the two light emitting means is configured to reach the line sensor directly after irradiating the bubble tube.

The invention according to claim 2 is the invention according to claim 1, wherein one of the two light emitting means emits light parallel to the line sensor, and the light is perpendicular to the line sensor by the reflector. It is configured to reflect, and the other of the two light emitting means emits light perpendicular to the line sensor.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the light emitting means is composed of a light source and a collimation lens that makes the light emitted from the light source parallel light.

According to the first aspect of the present invention, the tilt angle detector of the present invention includes a bubble tube, one line sensor disposed on the same horizontal plane as the bubble tube, and the same horizontal plane as the bubble tube. Since two light emitting means for projecting the shadow of the bubble in the bubble tube to different positions of the line sensor are provided, the tilt angle in the biaxial direction can be measured with one line sensor. For this reason, the inclination angle detector can be manufactured at a low cost by the amount of one line sensor. In addition, since there is no half mirror or line sensor above the bubble tube, it is possible to visually check whether the bubble is in the center by visual inspection of the bubble tube, which also makes it possible to detect the tilt angle and is convenient. Thereby, since the bubble tube can be shared for the inclination angle detector and the visual recognition of the horizontal plane, the surveying instrument can be made more inexpensive.
Further, the light emitted from one of the two light emitting means is reflected by a light reflector so as to reach the line sensor, and the light emitted from the other of the two light emitting means is directly applied to the line sensor. Therefore, the degree of freedom of the arrangement of the two light emitting means and the light reflector is increased, and it becomes possible to give the inclination angle detector a certain degree of freedom.
According to the invention of claim 2, in the invention of claim 1, one of the two light emitting means emits light parallel to the line sensor, and the light is a light reflector and is perpendicular to the line sensor. Since the light is reflected in the direction and the other of the two light emitting means emits light perpendicularly to the line sensor, both the light emitted from the two light emitting means is perpendicularly incident on the line sensor. In particular, it is possible to detect a tilt angle with high accuracy.

According to the invention of claim 3 , since the light emitting means is composed of a light source and a collimation lens that collimates the light emitted from the light source, the light emitted from the light source and the shadow of the bubbles are formed. Does not spread, the inclination angle detector can be made small.

  Further, since the light emitted from the light source does not spread and the light does not become weak, the edge of the shadow of the bubble can be reliably detected, and a highly reliable tilt angle detector can be obtained.

  Embodiments of the present invention will be described below. First, an inclination angle detector according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view for explaining the arrangement of the optical system of the tilt angle detector according to the first embodiment of the present invention. FIG. 2 is a diagram for explaining the line sensor output in the tilt angle detector.

  As shown in FIG. 1, the tilt angle detector 50 includes a circular bubble tube 52, two light emitting means 54a and 54b, one line sensor 56, and one mirror on a horizontal plane. 58 is arranged. The light emitting means 54a and 54b are composed of a light source 60 such as an LED, and a collimation lens 62 that converts the light emitted from the light source 60 into parallel rays. The bubble tube 52 is a tube in which a transparent liquid is sealed in a circular container, and a bubble 64 is sealed in the liquid, as in the conventional case. The line sensor 56 includes a large number of pixels (pixels) that generate electrical signals when receiving light, and each pixel is numbered sequentially from one to the other. Instead of the mirror 58, an appropriate light reflector such as a prism may be used.

  One light emitting means 54 a emits light L in parallel with the line sensor 56. The light emitting means 54 a, the mirror 58, and the line sensor 56 are arranged so that the light L is reflected by the mirror 58 in a right angle direction and enters the line sensor 56 perpendicularly. The other light emitting means 54 b faces the line sensor 56. Thus, the light L ′ emitted from the light emitting means 54 b enters the line sensor 56 perpendicularly. The bubble tube 52 is disposed at a position where the lights L and L ′ emitted from both the light emitting means 54 a and 54 b intersect.

Now, the shadows 66 and 66 ′ of the bubble 64 are projected onto the line sensor 56 by the lights L and L ′ emitted from the light emitting means 54 a and 54 b. The line sensor output is input to a CPU (calculation means) (not shown). As shown in FIG. 2, since the line sensor output sharply decreases at the edges of the shadows 66 and 66 ′, the CPU starts the shadow 66 from the pixel numbers P ₁ , P ₂ , P ₃ and P _{4 at which the} line sensor output rapidly decreases. , 66 'edge can be detected.

In advance, when the tilt angle detector 50 is horizontal, pixel numbers X ₀ and Y _{0 on} which the center 64a of the bubble 64 is projected by the light emitted from the light emitting means 54a and 54b are stored. If the pixel numbers P ₁ , P ₂ , P ₃ , and P ₄ corresponding to the edges of the shadows 66 and 66 ′ of the light emitted from each light emitting means 54a can be read, when the tilt angle detector 50 is horizontal, (P ₁ + P ₂ ) / 2 = X ₀ , (P ₃ + P ₄ ) / 2 = Y _0, and it can be seen that it is horizontal.

If the tilt angle detector 50 is tilted, (P ₁ + P ₂ ) / 2 = X ₀ and (P ₃ + P ₄ ) / 2 = Y ₀ are not satisfied. From the values of displacement (P ₁ + P ₂ ) / 2−X ₀ , (P ₃ + P ₄ ) / 2−Y ₀ in the X axis direction and Y axis direction of the center 64a of the bubble 64, the X axis direction and Y An inclination angle with respect to each of the axial directions can be obtained.

  According to the present embodiment, as described above, the tilt angle in the biaxial direction can be obtained with one line sensor 56, and the tilt angle detector 50 can be made inexpensive. In the case of the present embodiment, since the half mirror 18 and the line sensor 56 do not exist above the bubble tube 52 as in the conventional case, even if the bubble tube 52 is visually observed, it is inclined by visually confirming whether the bubble 64 is in the center. It is convenient to enable corner detection. Thereby, since the bubble tube 52 can be used for both the inclination angle detector and the visual recognition of the horizontal plane, the surveying instrument can be made more inexpensive.

  Next, an inclination angle detector according to the second embodiment of the present invention will be described with reference to FIG. The angle detector 50 also uses the bubble tube 52, the two light emitting means 54a and 54b, and the one line sensor 56 as in the first embodiment shown in FIG. A mirror is not required. One of the two light emitting means 54 a and 54 b emits light in a direction of 45 ° with respect to the line sensor 56, and the other 54 b of the two light emitting means 54 a and 54 b is connected to the line sensor 56. In contrast, light is emitted in the direction of −45 °. The bubble tube 52 is disposed at a place where the lights L and L ′ emitted from both the light emitting means 54 a and 54 b intersect.

  Also in this embodiment, one line sensor is obtained by detecting the edges of the shadows 66 and 66 ′ of the bubble 64 by the light L and L ′ emitted from the two light emitting means 54 a and 54 b by the line sensor 56. The inclination angle in the biaxial direction can be obtained with 56, and the same effect as in the first embodiment can be obtained. In addition, since the mirror 58 is not necessary, the tilt angle detector 50 can be made more inexpensive.

  In addition, the bubble tube 52 of both embodiments is mounted on a part of the surveying instrument to detect the inclination of the surveying instrument, but the vertical axis is rotated and the position of the bubble 64 is corrected with the adjusting screw, When the bubble 64 stops moving, the vertical axis and the direction of gravity are the same as in the conventional surveying instrument.

  By the way, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in both the above-described embodiments, the light L emitted from the light source 60 is collimated by the collimation lens 62, but the collimation lens 62 can be omitted.

  In the first embodiment, one light emitting means 54a emits light L parallel to the line sensor 56, and the light L is reflected by the mirror 58 in the vertical direction to the line sensor 56. The light emitting means 54b emits light L ′ perpendicular to the line sensor 56, but the light L emitted from one light emitting means 54a is reflected by the mirror 58 after irradiating the bubble tube 52. If the light L ′ emitted from the other light emitting means 54 b reaches the line sensor 56 and directly reaches the line sensor 56 after irradiating the bubble tube 52, the tilt angle detector 50 is reached. Depending on the shape required for the light, the emission direction of the light L and L ′ from both the light emission means 54a and 54b and the reflection direction of the light at the mirror 58 may be appropriately changed.

  Further, in the second embodiment, light is emitted from the two light emitting means 54 a and 54 b in the directions of 45 ° and −45 ° with respect to the line sensor 56, but the shape required for the inclination angle detector 50 is used. Depending on the above, the emission directions of the lights L and L ′ from both the light emitting means 54a and 54b may be appropriately increased or decreased from 45 ° and −45 °.

It is a top view of the optical system of the inclination angle detector which concerns on the 1st Example of this invention. It is a figure explaining the line sensor output in the said inclination-angle detector. It is a top view of the optical system of the inclination angle detector which concerns on the 2nd Example of this invention. It is a longitudinal cross-sectional view of the conventional inclination angle detector. It is a top view of the conventional inclination angle detector. It is a figure explaining the line sensor output in the conventional inclination angle detector.

Explanation of symbols

50 Inclination angle detector 52 Bubble tube 54a, 54b Light emitting means 56 Line sensor 58 Mirror (light reflector)
60 Light source 62 Collimation lens 64 Bubble

Claims (3)

A bubble tube, one line sensor arranged in the same horizontal plane as the bubble tube, and two lines that are arranged in the same horizontal plane as the bubble tube and project shadows of bubbles in the bubble tube to different positions of the line sensor. Light emitting means,
Light emitted from one of the two light emitting means is reflected by a light reflector after irradiating the bubble tube, and reaches the line sensor, and is emitted from the other of the two light emitting means. An inclination angle detector in which the light reaches the line sensor directly after irradiating the bubble tube.
One of the two light emitting means emits light parallel to the line sensor, and the light is reflected by the reflector in a direction perpendicular to the line sensor, and the other of the two light emitting means is The inclination angle detector according to claim 1 , wherein light is emitted perpendicularly to the line sensor.
The tilt angle detector according to claim 1 or 2, wherein the two light emitting means are configured by a light source and a collimation lens that converts light emitted from the light source into parallel rays.

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