JPS62282221A - Safety apparatus in scanning type laser surveying equipment - Google Patents

Abstract

PURPOSE:To prevent the danger of a large quantity of exposure to laser beam, by stopping the emission of laser beam when the rotational speed of a rotation speed detection mechanism reaches a set value or less. CONSTITUTION:The detection value of a rotational speed outputted from a rotational speed detection mechanism 6 is inputted to a rotational speed judging circuit 13 and a laser beam emitting drive circuit 14 is controlled corresponding to the magnitude of the rotational speed. In the circuit 13, two monostable multivibrators (#1MONO, #2MONO) having different time constants are connected to an OR gate and the output signal of the rotational speed detection mechanism 6 is inputted to #1MONO and triggered. Further, a reset signal is inputted to #2MONO by turning a power source ON and triggered for a definite time. By this constitution, when the number of rotations of a scanning optical member 1 is lowered or stopped, #1MONO is not triggered and the output of an OR gate is turned OFF by turning the outputs of #1MONO and #2MONO OFF, and the circuit 14 and a motor driving circuit 17 are stopped through a switching circuit 16.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention "Field of Industrial Application" This invention prevents the danger of being exposed to a laser beam in excess of the fermentation value in a scanning laser surveying instrument such as a two-dimensional level. This relates to safety equipment for

"Prior art, m points between invention and solution" Generally,
Since laser radiation is extremely dangerous to human health if exposed to large amounts, it is necessary to prevent exposure to laser radiation exceeding a certain standard value for a certain period of time.

However, in conventional scanning laser surveying instruments, when the scanning optical member is rotating, the human body is affected locally, so even if there is no effect, the rotation of the scanning optical member may stop due to a malfunction. If the laser is being emitted when the rotation speed is extremely low, there is a possibility that the device will be exposed to laser radiation exceeding a certain reference value for a certain period of time, which is dangerous.

"Means for Solving the Problems" In order to solve the above-mentioned conventional problems, the present invention constantly detects the rotational speed of a scanning optical member in a scanning laser surveying instrument, and sets the speed to a predetermined setting level. By installing a rotation speed discrimination circuit that stops laser emission when the temperature drops below i, the risk of large-scale exposure to laser beams can be prevented.
This paper proposes a safety device designed to prevent

"Embodiment" Below, a two-dimensional embodiment of the present invention shown in the drawings will be described. A scanning optical member 1 that scans a laser beam in a horizontal plane is rotated by a motor 3 and a belt 4 about a vertical rotation axis 2. A rotation detecting mechanism 6 is installed around the rotating body 5 to detect the rotational speed of the scanning optical member l.

The rotation detecting mechanism 6 shown in FIGS. 2 and 3 has a flange-shaped disk 7 around a four-rotator 5, an arbitrary number of slits 8 in the disk 7, and a photo frame with a part of the disk 7 sandwiched therebetween. The interrupter 9 detects the slit 8 and outputs a detected value of the rotational speed as a pulse signal corresponding to the rotational speed of the disk 7.

The rotation detection mechanism 6 shown in FIGS. 4 and 5 includes a reflective plate 0 provided around a part of the rotating body 5, and a reflective photointerrupter 11 provided around the rotating position of the reflective plate 10. Detected.

The detected value of the rotational speed is output as a pulse signal corresponding to the rotational speed of the rotating body.

The rotation detection mechanism 6 shown in FIG. 6 is provided with a light receiving sensor 12 around the rotating position of the laser beam exit window of the rotating body 5, and detects the scanning laser beam by the light receiving sensor 12, and detects the scanning laser beam and adjusts the rotational speed of the rotating body 5. The detected value of the rotational speed is output as a corresponding pulse signal.

The detected value of the rotational speed output as a pulse signal from the rotational speed detection mechanism 6 is inputted to the one-rotation speed determination circuit 13, which controls the laser emission drive circuit 14 depending on the magnitude of the rotational speed. .

As shown in FIG.
o, 112 MONO) are connected to the human power pin of the OR gate 15, the output signal of the rotation detection mechanism 6 is input to 11 MONO and it is triggered by the pulse, and t2 MONO is connected to the power supply pin. Input a reset signal activated by ON and wait for a certain period of time (for example, 5
seconds).

The time constant of II 14ONO is set longer than the detection pulse time during steady rotation of the scanning optical member 1,
During steady rotation, it is triggered again before the output turns OFF, and as long as steady rotation continues, the laser emission drive circuit 14 continues to be driven with the control output from the OR gate 15 kept ON.

Therefore, if the rotational speed of the scanning optical member 1 decreases or the rotation stops after that, 11 MONO will not be triggered, and the control output of the OR gate 15 will be OFF due to the outputs of 4 ONO and 2 MONO being turned off. , the laser emission drive circuit 14 and the motor drive circuit 17 are stopped via the switching circuit 16.

"Effects of the Invention" As described above, according to the present invention, in a scanning laser 4111 device configured to scan a laser beam by rotating a scanning optical member, rotation detection detects the rotational speed of the scanning optical member. and a rotation speed determination circuit configured to input a rotation speed signal of the rotation detection mechanism and stop driving the laser emission drive circuit when the rotation speed falls below a set value. The rotation speed of the scanning optical member is constantly detected by the rotation detection mechanism, and when the rotation speed decreases or stops, the rotation speed determination circuit stops driving the laser emission drive circuit. It is possible to reliably prevent excessive laser irradiation to the human body that exceeds the safety standard value.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an overview of the device according to the present invention;
FIG. 3 is a plan view of the same, FIG. 4 is a longitudinal side view of another example of the rotation detection mechanism according to the invention, and FIG. The same plan view,
FIG. 6 is a longitudinal sectional side view showing still another example of the rotation detection mechanism according to the present invention, FIG. 7 is a fi diagram of the rotation speed determination circuit according to the present invention, and FIG. 8 is a chart showing the principle of operation thereof. It is a diagram. 1...Scanning optical member, 6...Rotation speed detection mechanism, 13
...Rotation speed determination circuit, 14...Laser drive circuit.

Claims (1)

[Claims] 1) In a scanning laser surveying instrument configured to scan a laser beam by rotating a scanning optical member, a rotation detection mechanism that detects the rotation speed of the scanning optical member and a signal of the rotation speed of the rotation detection mechanism are provided. A safety device for a scanning laser surveying instrument, comprising: a rotational speed determination circuit configured to input a rotation speed and stop driving a laser emission drive circuit when the speed becomes less than a set value. .