JPH08320230A - Laser reference level setting target and laser reference level setting device - Google Patents

Abstract

PURPOSE: To surely detect the center of a target with simple constitution by scanning with laser beams in such a way as to cross a target in the driven state of a liquid crystal shutter on a reflecting surface, and detecting a reflected light from the reflecting surface. CONSTITUTION: Laser beams from a light emission diode 23 are made parallel laser beams by a collimator lens 24 and transmitted through a half mirror 26 or a holed mirror so as to be radiated on a target 35. A reflected light 25' reflected by the target 35 enters a laser oscillating device and is reflected by the half mirror 26. Part of the reflected light 25' is transmitted through a half mirror 32 and received by a detector 28. The remaining part of the reflected light 25' is received by a detector 34. The detectors 28, 34 are respectively provided with electrical filters synchronized with the frequency of a liquid crystal shutter. A control part 29 detects and computes a light receiving state by comparing light receiving quantities of the detectors 28, 34 or the like and controls a driving device according to the obtained light receiving state so as to determine the irradiating direction of the laser beams 25 from a laser transmitting device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser reference level setting device for setting a reference level that serves as a reference for the burying position, posture, etc. of a concrete pipe when burying a concrete pipe or the like in the soil. The present invention relates to improvement of a target used in a level setting device.

[0002]

2. Description of the Related Art As a typical work for burying concrete pipes in the soil, there is a work method in which the ground is dug down, concrete pipes are sequentially installed and buried in dug trenches, and backfilled.

[0003] The ground is dug deeper than the depth at which the concrete pipe is installed for each fixed straight section, and the concrete pipe is installed on a temporary stand provided at the bottom of the groove. At this time, the direction and inclination are adjusted so that the lowermost position of the inner surface of each concrete pipe is matched with each other, and then backfilling is performed.

Such concrete pipes are used for water supply and sewerage, etc.
It serves as a flow path for flowing a liquid substance, and is installed with a certain degree of inclination so as not to bend. When the buried concrete pipe meanders vertically and horizontally, the liquid substance stays, becomes clogged, or leaks into the ground, and cannot function as a flow path. Therefore, burying the concrete pipe requires an appropriate reference line.

A laser beam is convenient as such a reference line, does not slacken like a thread even at a long distance, does not become an obstacle during work, and further interferes with an operator, a concrete pipe, or the like. It will not be cut.

There is a laser reference level setting device for forming a reference line by the laser beam when installing a concrete pipe.

The laser reference level setting device has a laser aiming device and a target. The laser aiming device is installed at the starting point of the first dug down manhole or groove, and the target is installed at the other end of the groove. Is provided with a mark indicating the center position so that the center position can be known, and the target is installed so that the center position of the target matches the center position of the concrete pipe to be installed. The center position of the target is determined by a surveying device such as theodolite.

Next, the laser aiming device is adjusted such that a laser beam is emitted from the laser aiming device and the center of the target is irradiated with the laser beam. When the adjustment is completed, the laser beam emitted by the laser aiming device becomes the reference line for installing the concrete pipe.

However, during the construction work, there are vibrations during the work, vibrations when passing the vehicle, etc., and there are many displacements due to the vibrations. Moreover, when the construction is interrupted, the laser sighting device and the laser aiming device are frequently used. The position of the target must be adjusted.

Therefore, a laser reference level setting device capable of detecting the center of the target and a target have been proposed.

The laser reference level setting device comprises a laser aiming device and a target. Further, the laser aiming device has a means for emitting a polarized laser beam and a means for receiving a reflected laser beam from the target and is rotatably supported. The laser oscillating device described above, a driving device for rotating the laser oscillating means vertically and horizontally, and a control unit for driving the driving device according to a light receiving state of a reflected laser beam from the target. Further, the reflective surface of the target is a retroreflective surface having a reflective layer of small spheres or small prisms,
A quarter-wave birefringent plate is further attached to either the left or right half.

The polarized laser beam from the laser irradiation device is scanned so as to horizontally traverse the target, and when the target is irradiated with the laser beam, a reflecting surface on which a ¼ wavelength birefringent plate is attached. A polarized light different from the irradiated polarized light is reflected from. On the other reflecting surface, the polarized light is reflected while the polarized light is preserved. The laser oscillation device detects the state of the reflected light from the target, that is, the point where the polarization state changes, that is, the center of the target, and the controller controls the driving device to direct the laser beam to the center of the target.

[0013]

In the above-mentioned conventional laser reference level setting device and its target, a quarter wavelength birefringent plate is attached to half of the reflecting surface of the target to receive the reflected laser beam from the target. In this state, the center of the target is detected and the laser beam is emitted to the center to automatically adjust the position. Therefore, a polarized laser beam that is different from the polarized light of the irradiation laser beam is reflected on the reflecting surface on which the 1/4 wavelength birefringent plate is attached, while the other reflecting surface is in a state in which the polarized light of the irradiated laser beam is preserved. Since it is a normal reflecting surface that reflects light, a reflecting surface made of metal or the like is placed at a position opposite to the other reflecting surface across the reflecting surface on which the ¼ wavelength birefringent plate of the target plate is attached. If so, there is a problem that the center of the target cannot be detected because the reflected light whose polarization is preserved is reflected.

In view of the above situation, the present invention is capable of surely detecting the target center with a simple structure.

[0015]

The present invention provides a laser reference level setting target in which a plurality of liquid crystal shutters are provided on the reflecting surface of the target, a laser reference level setting target in which the opening and closing frequencies of the liquid crystal shutters are different, and From the laser reference level setting target that has a quarter-wave birefringent plate on the reflecting surface, and the laser reference level setting target that has the reflecting surface symmetrically with respect to the center of the target. A laser oscillating device having the laser aiming device having a laser beam emitting means and a reflected laser beam receiving means rotatably supported; a driving device for rotating the laser oscillating device; and the target. And a control unit for driving the driving device according to the reflected laser beam receiving state from the target, and the reflecting surface of the target. A laser reference level setting device provided with a plurality of liquid crystal shutters, a light receiving means having means for splitting reflected light, and a filter tuned to the opening / closing frequency of the liquid crystal shutter to determine the light receiving state of the reflected light split and received. Laser reference level setting device for detecting the center of the target by comparing the light amounts by detecting through the filter, and a laser reference in which a 1/4 wavelength birefringent plate is provided on the reflecting surface of the target and the light receiving means includes a polarizing means. The present invention relates to a level setting device.

[0016]

Operation: The liquid crystal shutter of the reflecting surface is driven, and the laser beam is scanned across the target, and the reflected light modulated by the opening / closing frequency of the liquid crystal shutter is reflected from the reflecting surface.
The reflected light reflected is detected by the light receiving means, and further only the reflected light is extracted and detected by the electric filter, and it is recognized that the received reflected light is from the target, and based on the change in the light receiving state. The target center is calculated, and the driving device is controlled based on the calculation result to determine the emission direction of the laser beam.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show a laser aiming device, and FIG.
Indicates a target 35.

First, the laser aiming device will be described.

A frame-shaped elevation frame 3 is provided in the vicinity of the front end of the frame 1 so as to be rotatable around a horizontal elevation shaft 2, and the elevation frame 3 can be pivoted about a pivot shaft 4 extending in the vertical direction. A laser oscillator 5 is provided.

A horizontal auxiliary frame 6 extending rearward is provided on the lower side of the elevation frame 3, and a horizontal pin 7 is projectingly provided on the horizontal auxiliary frame 6 between the pin 7 and the frame 1. A spring 8 is stretched to urge the elevation frame 3 clockwise in FIG. Also, the frame 1
The elevation motor 9 is provided at the base of the elevation motor 9
The elevation screw 10 is connected to the output shaft of the, and a nut 11 is screwed into the elevation screw 10, and a pin 12 protruding from the nut 11 is engaged with the pin 7.

A vertical auxiliary frame 13 is provided on the side of the elevation frame 3, a swing motor 15 is provided on the vertical auxiliary frame 13 via a gear box 14, and a guide shaft 16 is provided horizontally from the gear box 14. An oscillating screw 17 is extended, and the oscillating screw 17 is connected to the output shaft of the oscillating motor 15. A nut block 18 screwed onto the swing screw 17 is slidably fitted on the guide shaft 16.

A pin 19 protruding horizontally from the rear end of the laser oscillator 5 is engaged with an engaging pin 20 protruding from the nut block 18 and provided between the pin 19 and the vertical auxiliary frame 13. The laser oscillating device 5 is urged horizontally by the spring 21, that is, rightward in FIG.

The laser oscillation device 5 is rotated in two orthogonal directions by driving the elevation motor 9 and the swing motor 15.

Next, the laser oscillator 5 will be briefly described with reference to FIG.

In the figure, reference numeral 22 denotes a laser light emitting portion, the laser light emitting portion 22 has a light emitting diode 23 and a collimating lens 24, and the laser beam from the light emitting diode 23 is collimated by the collimating lens 24. 25
Then, the light passes through the first half mirror 26 or the perforated mirror and is irradiated onto the target 35.

Reflected light 2 reflected by the target 35
5'is incident on the laser oscillating device 5, reflected light 25 'is incident on the first half mirror 26, and a part of the reflected light 25' is transmitted through the second half mirror 32 to be combined. The light is received by the first light receiving means including the focusing lens 27 and the first detector 28. When the first detector 28 receives the reflected light 25 ′ via the focusing lens 27, the first detector 28 inputs a detection signal to the control unit 29. The remaining part of the reflected light 25 ′ is reflected by the second half mirror 32, and a second part including a focusing lens 33, a second detector 34, etc.
The light is received by the light receiving means. When the second detector 34 receives the reflected light 25 ′ via the focusing lens 33, the second detector 34 inputs a detection signal to the controller 29.

Each of the first detector 28 and the second detector 34 is provided with an electric filter tuned to the frequency of the liquid crystal shutter described later.

The control unit 29 includes the first detector 28 and the second detector 28.
The light receiving state is detected and calculated by comparing the amount of light received by the detector 34, and the driving device is controlled according to the obtained light receiving state to determine the irradiation direction of the laser beam 25 from the laser oscillator 5. The drive device is a power transmission means such as a elevation motor 9, an oscillation motor 15, an elevation screw 10, an oscillation screw 17, etc., and an elevation motor control unit 30 and an oscillation motor control unit for driving the elevation motor 9 and the oscillation motor 15. It consists of 31 mag.

Next, the target 35 will be described with reference to FIG.

The surface of the target plate 36 is a retroreflective surface composed of small spheres, small prisms or the like.
A liquid crystal shutter 39 and a liquid crystal shutter 40 are provided on the reflecting surface 6 so as to be divided into a left reflecting surface 37 and a right reflecting surface 38. A control means (not shown) for opening and closing the liquid crystal shutter 39 and the liquid crystal shutter 40 at different frequencies is provided at a required position of the target 35, for example, on the back surface. The boundary line between the liquid crystal shutter 39 and the liquid crystal shutter 40 is set to be the center of the target of the target 35.

The operation will be described below.

First, the laser sighting device is installed horizontally at the starting point and the target 35 is installed at the target position. Activating the laser aiming device, the laser beam 25
Is irradiated, and the left and right of the irradiation direction and the inclination are roughly set manually. After setting, activate automatic adjustment.

The oscillating motor 15 is rotated, the oscillating screw 17 is rotated, and the laser oscillating device 5 of the laser aiming device is moved to the oscillating shaft 4 via the nut block 18, the engaging pin 20, and the pin 19. It rotates back and forth horizontally in the center,
The laser beam 25 is horizontally scanned back and forth.

When the laser beam 25 crosses the target 35, it is reflected by the left reflecting surface 37 and the right reflecting surface 38.
When the liquid crystal shutter 39 and the liquid crystal shutter 40 are driven, the reflected light 25 ′ on the left reflection surface 37 and the right reflection surface 38.
Is blocked by the opening and closing of the liquid crystal shutter 39 and the liquid crystal shutter 40, and is modulated into reflected light having the same frequency as the opening and closing frequencies of the liquid crystal shutters.
It becomes as shown in (A).

The reflected light 25 'is generated by the laser oscillator 5
Light, and is split by the second half mirror 32,
The reflected light 2 is reflected by the first detector 28 and the second detector 34.
5'is detected. As described above, the first detector 28 and the second detector 34 are provided with an electric filter that transmits a frequency tuned to the opening / closing frequency of the liquid crystal shutter, and the first detector 28 is connected to the left reflecting surface 37. Only the reflected light 25 'is received and its output is input to the control unit 29,
The detector 34 receives only the reflected light 25 ′ from the right reflecting surface 38 and inputs its output to the controller 29. The output of the control unit 29 when the deviations of the two detectors 28 and 29 are taken is as shown in FIG. 6B, and the center of the target can be detected at the point where the outputs are inverted. . The control unit 29 controls the swing motor control unit 31 to drive the swing motor 15, so that the irradiation direction of the laser beam 25 is set to the target center of the target 35 (the left reflection surface 37 and the right reflection surface 38). Boundary).

Further, the first detector 28 and the second detector 34 are turned to the target 35 through the electric filter.
It is possible to receive only the reflected light from, and it is possible to remove noise from other unnecessary reflectors, and the detection accuracy is improved.

Another target 35 according to this embodiment will be described with reference to FIG.

A cross line 42 is marked on the center of the target of the rectangular target plate 41 (in the case of this figure, the center of the target coincides with the center of the figure), and left, right, up and down with the intersection of the cross lines as the center. Left reflective surface 3 at each symmetrical position
7, a right reflecting surface 38, an upper reflecting surface 44, and a lower reflecting surface 45 are provided, the left reflecting surface 37 and the right reflecting surface 38 have at least the same width in the horizontal direction, and the upper reflecting surface 44 and the lower reflecting surface 45 have at least the same width. The vertical width is the same. If the widths are not the same, the left reflecting surface 37 and the right reflecting surface 38, and the upper reflecting surface 44 and the lower reflecting surface 45 are symmetrical with respect to the vertical line and the horizontal line of the cross line. May be.

The left reflecting surface 37, the right reflecting surface 38, the upper reflecting surface 44, and the lower reflecting surface 45 are obtained by laminating a retroreflective layer composed of small spheres or small prisms on the target plate 41. 35 left reflective surface 37, right reflective surface 3
8. A liquid crystal shutter is further attached to the surfaces of the upper reflection surface 44 and the lower reflection surface 45, and a shutter control circuit for driving the liquid crystal shutter at a required frequency is provided at a required position of the target 35, for example, the back surface.

The laser aiming device is installed horizontally at the starting point, and the target 35 is installed at the target position.
The laser aiming device is operated to irradiate the laser beam 25, and the left and right of the irradiation direction and the inclination are roughly set manually. After setting, activate automatic adjustment.

The oscillating motor 15 is rotated, the oscillating screw 17 is rotated, and the laser oscillating device 5 of the laser aiming device is moved to the oscillating shaft 4 via the nut block 18, the engaging pin 20, and the pin 19. It rotates back and forth horizontally in the center,
The laser beam 25 is horizontally scanned back and forth. Laser beam 25
When the beam crosses the target 35, the reflected light 25 ′ from the left reflecting surface 37 and the right reflecting surface 38 enters the laser oscillator 5, and the reflected light 25 ′ is reflected by the first detector 28 and the second detector 34. Is detected. As shown in FIG. 8, the received light signals from both detectors 28 and 34 are in the form of pulses having the same width and the same shape with a predetermined time difference. The first detector 28 and the second detector 34
If the signals from the above are pulses having the same width with a predetermined time difference, the control unit 29 recognizes that the received reflected light is from the target 35, and determines the horizontal center of gravity of the two received signals, that is, the horizontal position. The intersection of the cross lines 41 in the direction is calculated. The control unit 29 controls the swing motor control unit 31 to drive the swing motor 15 to match the irradiation direction of the laser beam 25 with the horizontal center of gravity position.

Next, the elevation motor 9 is driven to rotate the elevation screw 10, and the nut 11, pin 12, and
The laser oscillation device 5 is tilted in the vertical direction at a required angle about the elevation axis 2 via the pin 7 and the horizontal auxiliary frame 6, and scanning is started in the vertical direction. The first detector 2
8. In the state of the received light signal from the second detector 34, the control unit 29 calculates the vertical center of gravity position, that is, the intersection of the cross lines 41 in the vertical direction, as described above. The elevation motor control unit 30 is controlled to drive the elevation motor 9, and the irradiation direction of the laser beam 25 is further matched to the vertical center of gravity position. The irradiation point of the laser beam 25 is the cross line 4
Match the intersection of 1.

When the liquid crystal shutter is driven, the reflected light is blocked in accordance with the opening and closing of the liquid crystal shutter and is modulated at the driving frequency of the liquid crystal shutter. Further, by opening the electric filter, the first detector 28 and the second detector 34 can receive only the reflected light from the target 35, and remove the noise from other unnecessary reflectors. Therefore, the detection accuracy is improved.

In the case of this embodiment, the second half mirror 3
2, the focusing lens 33 and the second detector 34 may be omitted, and the position of the center of gravity may be obtained from the received light signal from the first detector 28. Further, instead of the second half mirror 32, other light splitting means such as a beam splitter may be used. Further, the electric filter may be provided in the control unit 29.

The liquid crystal shutters provided on the left reflecting surface 37, the right reflecting surface 38, the upper reflecting surface 44, and the lower reflecting surface 45 may be opened and closed at the same frequency, or may be opened and closed at different frequencies. Good. When opened and closed at different frequencies, the left reflecting surface 37, the right reflecting surface 38, the upper reflecting surface 44,
The lower reflection surface 45 can be individually recognized.

The reflecting surface of the target 35 is the left reflecting surface 3
7, the right reflecting surface 38, the upper reflecting surface 44, and the lower reflecting surface 45 may be continuous, and the width of the reflecting surface may be changed in the horizontal direction and the vertical direction. If a quarter-wave birefringent plate is provided on the surface of the liquid crystal shutter and a polarization beam splitter is provided instead of the second half mirror, the phase of the reflected laser light reflected by the target reflection surface with respect to the irradiation laser light Is converted by 90 °, and the polarization beam splitter transmits only the beam converted by 90 ° in phase, so that the light rays reflected by unnecessary reflection surfaces are cut and the reflected light is more easily separated. Further 1/4
The wavelength birefringent plate may be provided on the back side of the liquid crystal shutter,
Furthermore, instead of the beam splitter, a separate polarizing plate may be provided on the target side of the second half mirror.

[0048]

As described above, according to the present invention, the reflected light from the target can be surely recognized, the target center can be accurately detected, and the irradiation position of the laser beam can be matched with the target center without malfunction. In addition, the irradiation position of up, down, left and right can be matched with the center of the target without rotating the target, eliminating the need for an auxiliary worker and eliminating time loss, improving work efficiency and requiring a target rotation mechanism. Since it does not have a structure, the structure is simple, and since it is not necessary to use polarized light for determining the center, the optical system is simplified. Furthermore, by providing a liquid crystal shutter, noise can be removed and malfunctions can be prevented. Exert the effect.

[Brief description of drawings]

FIG. 1 is a side sectional view of a laser aiming device according to an embodiment of the present invention.

FIG. 2 is a front view of the laser aiming device.

FIG. 3 is a view on arrow AA of FIG.

FIG. 4 is a skeleton view of a main part of a laser oscillator of the laser aiming device.

FIG. 5 is a perspective view of a target according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram showing an example of a state of reflected light from the target.

FIG. 7 is a front view of another target according to an embodiment of the present invention.

FIG. 8 is an explanatory diagram showing an example of a light receiving state of the detector.

[Explanation of symbols]

 5 laser oscillator 9 elevation motor 15 oscillation motor 22 laser light emitting section 25 laser beam 25 'reflected light 28 first detector 29 control section 30 elevation motor control section 31 oscillation motor control section 34 second detector 35 target 37 Left reflective surface 38 Right reflective surface 44 Upper reflective surface 45 Lower reflective surface

Claims (7)

[Claims] 1. A target for laser reference level setting, wherein a plurality of liquid crystal shutters are provided on a reflecting surface of the target. 2. The laser reference level setting target according to claim 1, wherein the opening and closing frequencies of the liquid crystal shutter are different. 3. The laser reference level setting target according to claim 1, wherein a ¼ wavelength birefringent plate is provided on the reflecting surface. 4. The laser reference level setting target according to claim 1, wherein the reflecting surfaces are provided symmetrically with respect to the center of the target in the left-right direction and the up-down direction. 5. A laser oscillating device comprising a laser aiming device and a target, wherein the laser aiming device has a laser beam emitting means and a reflected laser beam receiving means and is rotatably supported. A drive device for rotating the device, and a control unit for driving the drive device according to a reflected laser beam receiving state from the target are provided, and a plurality of liquid crystal shutters are provided on a reflective surface of the target. Laser reference level setting device. 6. The light receiving means has a means for splitting the reflected light and a filter tuned to the opening / closing frequency of the liquid crystal shutter, and the light receiving state of the reflected light split and received is detected through the filter to obtain the light quantity. The laser reference level setting device according to claim 4, wherein the target center is detected by comparing 7. The laser reference level setting device according to claim 6, wherein a ¼ wavelength birefringent plate is provided on the reflecting surface of the target, and the light receiving means comprises a polarizing means.