JP4169904B2 - Inclination angle measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tilt angle measuring device such as a bubble tube in which liquid and bubbles are sealed in a glass container and the bubbles are moved according to the tilt angle of the glass container.
[0002]
[Prior art]
There is a bubble tube as a device for detecting the inclination of the device, and the bubble tube is filled with liquid and bubbles in a glass container. When a device such as a surveying instrument that requires leveling is installed, an inclination angle measuring device provided with the bubble tube is used. There is a photoelectric bubble tube that photoelectrically detects the movement of bubbles in the bubble tube, and a conventional tilt angle measuring apparatus including the photoelectric bubble tube will be described with reference to FIG.
[0003]
The photoelectric bubble tube 1 is configured by combining a light source 2 and light receiving elements 3, 4 and a bubble tube 5, and an inclination angle is detected based on a signal from the photoelectric bubble tube 1.
[0004]
The light source 2 is disposed below the bubble tube 5, and the optical axis of the light source 2 is orthogonal to the axis of the bubble tube 5. A pair of the light receiving elements 3 and 4 are disposed with a required distance therebetween at positions symmetrical to the optical axis of the light source 2 while facing the light source 2 with the bubble tube 5 interposed therebetween. As the light receiving elements 3 and 4, photoelectric conversion elements are used.
[0005]
The detection light 7 emitted from the light source 2 passes through the bubble tube 5 and reaches the light receiving elements 3 and 4, and a light receiving current corresponding to the amount of light received by the light receiving elements 3 and 4 is output.
[0006]
The detection light 7 emitted from the light source 2 is transmitted through only the liquid 11 portion of the bubble tube 5, but is reflected at the boundary surface between the bubble 12 and the liquid 11 when the bubble 12 is present. Incidence to both light receiving elements 3 and 4 is blocked. Accordingly, the amount of the detection light 7 incident on the light receiving elements 3 and 4 varies depending on the position of the bubble 12. Since the position of the bubble 12 moves with inclination, the inclination angle is detected by detecting the difference in the amount of light received between the light receiving element 3 and the light receiving element 4.
[0007]
Alcohol-based, ether-based hydrocarbons, or a mixed solution thereof has been widely used as the liquid sealed in the bubble tube of the tilt angle measuring device. For example, a mixed solution of ethanol and diethyl ether and a mixed solution of n (normal) -hexane and n (normal) -heptane can be given.
[0008]
FIG. 9 shows the experimental results showing the detection accuracy of the bubble tube 5 in which a conventional hydrocarbon-based (in this case, n-hexane and n-heptane) mixed liquid is enclosed. FIG. 9 shows an example of the result of actual measurement of the relationship between the tilt angle and the sensor output in the range of ± 4 ′ when the temperature is sequentially changed from 25 ° C. → −20 ° C. → 50 ° C. → 25 ° C.
[0009]
In this example, the reproducibility in the range of ± 4 ′ at 25 ° C. is 10 ″ at the maximum, and the temperature shift at the zero point (origin) from −20 ° C. to 50 ° C. is about 0.12 ″ / ° C., ± The temperature drift of the sensitivity in the range of 3 ′ is about 12%, and the linearity (operation range) is obtained in the range of ± 3 ′.
[0010]
[Problems to be solved by the invention]
However, the reproducibility, the temperature shift of the zero point, the temperature drift, and the linearity of the bubble tube 5 filled with a conventional hydrocarbon-based mixed liquid (n-hexane and n-heptane) are all satisfactory performances. The cause is that there is a problem with the liquid sealed in the bubble tube, and the specific cause is as follows.
[0011]
That is, since the mixed solution used as the encapsulating liquid has a large coefficient of thermal expansion, the size of encapsulated bubbles changes depending on the environmental temperature.
[0012]
Moreover, although the container which enclosed the said mixed solution is made from glass, since the wettability with respect to the glass of the said mixed solution is bad, a bubble does not move smoothly.
[0013]
Furthermore, since the mixed solution has a low thermal conductivity and a large specific heat, the followability with respect to the environmental temperature is poor, and as a result, the performance of the bubble tube may be adversely affected.
[0014]
In view of such circumstances, the present invention has a thermal expansion coefficient smaller than about 1/100 or less than that of a conventional liquid, has extremely good wettability with respect to glass, and encloses a mixed liquid with high thermal conductivity in a glass container together with bubbles. An inclination angle measuring device is provided.
[0015]
[Means for Solving the Problems]
The present invention provides an inclination angle measuring apparatus for measuring an inclination angle by enclosing a solution and bubbles in a glass container and detecting the amount of movement of the bubbles, and the solution contains N-methylformamide and a solvent. The present invention relates to a tilt angle measuring apparatus, and the solvent is a nitrogen compound such as acetonitrile, alcohols such as methanol and ethanol, phenols, ethers, acetals, ketones, esters, fatty acids, acid anhydrides, sulfur compounds, 2 -Two or more functionalities of methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol, diethylene glycol, triethylene glycol, lactic acid, lactate ester, methyl salicylate, methyl acetoacetate, ethyl acetoacetate At least one of a group-containing compound and an inorganic solvent The present invention relates to a tilt angle measuring apparatus that is one solvent, and further relates to a tilt angle measuring apparatus in which the mixing ratio of the N-methylformamide and the solvent is a ratio of 3: 7 by volume.
[0016]
The N-methylformamide has a thermal expansion coefficient as small as about 1/100 or less of that of hydrocarbon liquids such as methanol, ethanol, n-hexane and n-heptane, which are conventionally used, and has a high thermal conductivity. Very good wettability to glass.
[0017]
Nitrogen compounds such as acetonitrile, alcohols such as methanol and ethanol, phenols, ethers, acetals, ketones, esters, fatty acids, acid anhydrides, sulfur compounds, compounds having two or more functional groups as diluents The viscosity of N-methylformamide is reduced by mixing at least one of the inorganic solvents.
[0018]
As for the mixing ratio, when N-methylformamide and the solvent are respectively 3: 7, the bubble length temperature change (%) is extremely small, and the ease of movement of the bubbles is improved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
An inclination angle measuring apparatus having a photoelectric bubble tube will be described with reference to FIG. In this embodiment, the configuration of the liquid in the bubble tube is different from the above-described conventional example, but the other configuration is the same as that of the above-described conventional example, and is the same as that in FIG. 8 in FIG. The same sign is attached to the thing.
[0021]
The photoelectric bubble tube 1 is configured by combining a light source 2 and light receiving elements 3 and 4 and a bubble tube 5 ′, and an inclination angle is detected based on a signal from the photoelectric bubble tube 1.
[0022]
The light source 2 is disposed below the bubble tube 5 ', and the optical axis of the light source 2 is orthogonal to the axis of the bubble tube 5'. A pair of the light receiving elements 3 and 4 are disposed with a required distance therebetween at positions symmetrical to the optical axis of the light source 2 while facing the light source 2 with the bubble tube 5 ′ interposed therebetween. As the light receiving elements 3 and 4, photoelectric conversion elements are used.
[0023]
The light source 2 is driven by a light source driving unit 6, and detection light 7 emitted from the light source 2 passes through the bubble tube 5 ′ and reaches the light receiving elements 3 and 4, and is received by the light receiving elements 3 and 4. The received light current corresponding to the received light amount is output to the tilt angle detection control unit 8. The inclination angle detection control unit 8 includes a differential amplifier 9 and a control calculation unit 10. The differential amplifier 9 amplifies a current difference between output signals from the light receiving elements 3 and 4 and converts the current voltage into current. And output to the control calculation unit 10. The control calculation unit 10 processes the signal from the differential amplifier 9 and calculates the tilt angle.
[0024]
The detection light 7 emitted from the light source 2 passes through only the liquid 11 ′ portion of the bubble tube 5 ′, but is reflected at the boundary surface between the bubble 12 and the liquid 11 ′ where the bubble 12 is present. Therefore, the incident on both the light receiving elements 3 and 4 is blocked. Accordingly, the amount of the detection light 7 incident on the light receiving elements 3 and 4 varies depending on the position of the bubble 12. Since the position of the bubble 12 moves with inclination, the inclination angle is detected by detecting the difference in the amount of light received between the light receiving element 3 and the light receiving element 4.
[0025]
Such an inclination angle measuring apparatus is mounted on various surveying instruments, for example, laser surveying instruments. The outline of a laser surveying instrument equipped with an inclination angle measuring device will be described below with reference to FIGS.
[0026]
The laser surveying instrument rotates and irradiates a directional laser beam in the horizontal direction to form an irradiation surface, and a light receiving device (not shown) located on the rotation irradiation surface detects and detects the laser beam. By doing so, a reference line and a reference plane can be obtained.
[0027]
The laser beam emitting portion 14 is supported so as to be tiltable in all directions, and has a rotating portion 15 that can rotate around the optical axis of the laser beam emitting portion 14 at the head. The laser beam emitting section 14 is provided with the photoelectric bubble tubes 16 and 17 orthogonal to the horizontal direction described above, and further provided with a vertical inclination sensor 18, the inclination sensor 18, and the photoelectric bubble tubes 16 and 17. And the inclination detection control part 19 comprises the inclination detection apparatus.
[0028]
The rotating unit 15 deflects the laser beam 21 emitted in the vertical direction in the horizontal direction and is rotated by the scanning motor 22 to rotate and irradiate the laser beam 21.
[0029]
Arms 23 and 24 (not shown for arm 24) are extended from the laser beam emitting portion 14 in two orthogonal horizontal directions, and the tips of the arms 23 and 24 are engaged with an inclination mechanism.
[0030]
The tilt mechanism includes two sets of tilt drive units 25 and 26 (the tilt drive unit 26 is not shown) provided for each of the arms 23 and 24, and a tilt control unit (see FIG. 5) that controls the tilt drive units 25 and 26. The tilt drive units 25 and 26 are provided with a screw 27 extending in the optical axis direction of the laser beam emitting unit 14, and a nut 28 that is screwed into the screw 27 and abuts against the tips of the arms 23 and 24. And an inclination adjusting motor 32 for rotating the screw 27 through gears 30 and 31. Also, what is indicated by 29 in the figure is a focus adjusting device, and the laser beam 21 is focused by moving the condensing lens 33 disposed in the optical path of the laser beam emitting section 14 in the optical axis direction. .
[0031]
As shown in FIG. 2, the tilt detection control unit 19 includes a differential amplifier 9 to which a light reception signal from the light receiving elements 3 and 4 is input, and a control calculation unit that generates a control signal based on the signal from the differential amplifier 9. 10, the drive circuit 35 drives the tilt adjusting motor 32 based on the control signal from the control calculation unit 10, and the optical axis of the laser beam emitting unit 14 is adjusted to a vertical or required angle.
[0032]
A laser beam 21 is irradiated from the rotating unit 15 in the horizontal direction, and an irradiation surface is formed by rotating the rotating unit 15 by the scanning motor 22, and the scanning position of the laser beam is set to a predetermined position by a light receiving device. A reference plane can be obtained by setting.
[0033]
By obtaining the reference plane, it is possible to easily determine a wide range of work positions. For example, setting of a window position in interior work of building work or leveling of civil engineering work.
[0034]
The bubble tube 5 ′ of the photoelectric bubble tubes 1, 16, and 17 is a transparent glass container, and a solution containing N-methylformamide that is a transparent liquid and a solvent is sealed in the glass container.
[0035]
The N-methylformamide has a thermal expansion coefficient of 0.08 × 10 ⁻³ / ° C., conventional methanol (1.19 × 10 ⁻³ / ° C.), ethanol (1.08 × 10 ⁻³ / ° C.). , N-hexane (1.35 × 10 ⁻³ / ° C.) and n-heptane (1.22 × 10 ⁻³ / ° C.), etc. The thermal conductivity is large, and the wettability to glass is very good (see FIG. 4).
[0036]
However, since the N-methylformamide has a high viscosity, acetonitrile is mixed as a solvent. As shown in FIG. 4, when N-methylformamide and acetonitrile are in a ratio of 3: 7 (volume ratio) as shown in FIG. 4, the bubble length temperature change (%) is very small, and the movement of the bubbles is also easy to move. Experimental results with good results were obtained.
[0037]
As the solvent, in addition to acetonitrile, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, isobutyl alcohol, isopentyl alcohol, benzyl alcohol, and cyclohexanol may be used.
[0038]
Also, hydrocarbons such as toluene, xylene, ethylbenzene, naphthalene, tetralin, butylbenzene, diethylbenzene, pentylbenzene, cyclohexane, phenols such as phenol, cresol, xylenols, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether Such as ethers, acetals, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acid anhydride solutions, methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, etc. Esters, fatty acids, nitromethane, nitroethane, nitrobenzene, acetonitrile, propionitrile, succinonitrile, butyronitrile, isobutyronitrile, valeronitrile, benzo Nitrogen compounds such as tolyl, sulfur compounds such as carbon disulfide, dimethyl sulfide, diethyl sulfide, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol, diethylene glycol, triethylene glycol, A compound having two or more functional groups such as lactic acid, lactic acid ester, methyl salicylate, methyl acetoacetate and ethyl acetoacetate, water, an inorganic solvent such as propylene carbonate, and the like can also be used.
[0039]
By adding these solvents to N-methylformamide, the kinematic viscosity is 0.3 to 0.8 cps (25 ° C.), the boiling point is 60 to 130 ° C., the freezing point is −30 ° C. or less, the thermal expansion coefficient is small, and the thermal conductivity. Is large and wettability to glass is also good.
[0040]
Thus, when a mixed solution of N-methylformamide and methanol, ethanol or the like is used, the expansion coefficient is decreased, the thermal conductivity is increased, and the wettability to glass is improved. N-methylformamide is a polar solvent. For this reason, the polarity of hydrocarbon-based molecules such as methanol and ethanol attracts the polarity of N-methylformamide to form a complex and coordinate bond.
[0041]
FIG. 5 shows an experimental result representing the detection accuracy of the bubble tube 5 ′ in which the mixed liquid according to the present invention is sealed.
[0042]
FIG. 5 shows an example of the result of actual measurement of the relationship between the tilt angle and the sensor output in the range of ± 4 ′ when the environmental temperature is changed in the order of 25 ° C.−20 ° C. → 50 ° C. → 25 ° C. ing. In this example, the reproducibility in the range of ± 4 ′ at 25 ° C. is 6 ″ or less, the temperature shift of the zero point (origin) at −20 ° C. to 50 ° C. is about 0.07 ″ / ° C., ± The temperature drift of the sensitivity in the 3 ′ range is about 6%, and a good linearity (operating range) is obtained in the ± 4 ′ range.
[0043]
In the case of the above-mentioned conventional hydrocarbon-based mixed solution, as shown in FIG. 9, the reproducibility is 10 ″ at maximum, the temperature shift at the zero point (origin) is 0.12 ″ / ° C., and the temperature drift of sensitivity is maximum. Since it is 12% and the operation range is ± 3 ′ or more, the detection accuracy is greatly improved by the present invention.
[0044]
Furthermore, durability tests, such as a temperature change test (heat shock) and a time-dependent change test, were performed using the bubble tube which enclosed the liquid mixture which concerns on this invention. The results are shown in FIGS.
[0045]
FIG. 6 shows the result of actual measurement of how the zero point shift amount changes with time when a sudden temperature change of 30 ° C. from 55 ° C. to 30 ° C. is given. It takes 1 hour or more to eliminate the zero point shift, but it returns to 15 ″ or less in 10 minutes and 6 ″ or more in 20 minutes, and there is no practical problem.
[0046]
FIG. 7 shows the result of measuring the change in the relationship between the inclination angle and the sensor output at 25 ° C. during 30 cycles of the temperature cycle (25 ° C.−30 ° C. → 60 ° C. → 25 ° C., 8 hours). An example is shown. A shift of about 7 ″ in the shift width is seen over the whole, but the sensitivity is not changed and there is no problem. In the results of the three units tested, the shift amount is 10 ″ at the maximum and no change in sensitivity was observed. .
[0047]
As described above, the solution sealed in the tilt angle measuring device (bubble tube) according to the present invention has been conventionally used in terms of expansion coefficient, thermal conductivity, wettability to glass, sensitivity to environmental temperature changes, and environmental temperature durability. It can be seen that this is superior to alcohol-based and ether-based materials.
[0048]
The tilt angle measuring device of the present invention is not limited to the solvent in the above-described embodiment, and it is needless to say that two or more kinds of solvents may be used in combination.
[0049]
【The invention's effect】
As described above, according to the present invention, since a solution containing N-methylformamide and a solvent is sealed in the bubble tube of the tilt angle measuring device, the expansion coefficient of the solution is the conventional alcohol-based or ether-based hydrocarbon. The system solution is reduced to about 1/100 or less, and the size of the bubbles hardly changes depending on the environmental temperature. In addition, since the wettability to glass is very good, the movement of bubbles is smooth, and since the thermal conductivity is small and the specific heat is large, the followability to the environmental temperature is good, the performance of the bubble tube is improved, and the inclination angle is measured. Various excellent effects such as improved detection accuracy of the apparatus are exhibited.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an outline of an embodiment of the present invention.
FIG. 2 is a block diagram showing an outline of an inclination angle measuring device mounted on a laser surveying instrument.
FIG. 3 is a schematic sectional view of a laser surveying instrument equipped with an inclination angle measuring device.
FIG. 4 is a table comparing the performance of the sealing liquid in the bubble tube and the performance of a conventional sealing liquid in the embodiment of the present invention.
FIG. 5 is a diagram showing the operation of the embodiment of the present invention.
FIG. 6 is a diagram showing the operation of the embodiment.
FIG. 7 is a diagram showing the operation of the embodiment.
FIG. 8 is a block diagram showing an outline of a conventional example.
FIG. 9 is a diagram showing the operation of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photoelectric bubble tube 2 Light source 3 Light receiving element 4 Light receiving element 5 'Bubble tube 6 Light source drive part 7 Detection light 8 Inclination angle detection control part 9 Differential amplifier 10 Control calculating part 11' Liquid 12 Bubble 19 Inclination detection control part 35 Drive circuit

Claims (3)

  An inclination angle measuring apparatus for measuring an inclination angle by enclosing a solution and bubbles in a glass container and detecting a movement amount of the bubbles, characterized in that the solution contains N-methylformamide and a solvent. Tilt angle measuring device. Solvents are nitrogen compounds such as acetonitrile, alcohols such as methanol and ethanol, phenols, ethers, acetals, ketones, esters, fatty acids, acid anhydrides, sulfur compounds, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol, diethylene glycol, triethylene glycol, lactic acid, lactic acid ester, methyl salicylate, methyl acetoacetate, ethyl acetoacetate compound, inorganic solvent The tilt angle measuring device according to claim 1, which is at least one of the solvents.   The tilt angle measuring device according to claim 1 or 2, wherein the mixing ratio of N-methylformamide and the solvent is a volume ratio of 3: 7.

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