JPS61286780A - Ultrasonic range finder - Google Patents

Abstract

PURPOSE:To enable the range finding of a relatively long distance without being affected by the surface unevenness of a matter, by arranging the relay mounted to the matter in a freely detachable manner in a state spaced apart from the main body of a range finder. CONSTITUTION:A range finder main body 1 is equipped with a transmitting means 10 for intermittently sending out a transmitting signal being an ultrasonic pulse, a receiving means 20 for receiving a return signal being the ultrasonic pulse returned from a relay 2, a means 30 for calculating the distance up to the relay 2 on the basis of the time difference between the time when the trans mitting signal was sent out from the means 10 and the time when the return signal was received by the means 20 and a distance display means 40 for displaying the distance calculated by the means 30. The relay 2 is equipped with the receiving means 5 for receiving the transmitting signal sent out from the range finder main body 1 and the transmitting means 60 for sending out the return signal toward the range finder main body 1 upon the reception of the return transmitting signal. By using the relay 2, accurate measurement can be performed even if unevenness is present on the surface of the matter and the measurement of a relatively long distance is enabled.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an ultrasonic distance meter, and more particularly, to a repeater detachably attached to an object, and a rangefinder body disposed apart from the repeater. The present invention relates to an ultrasonic distance meter that transmits ultrasonic waves from at least one of a distance meter main body and a repeater, and measures the distance to an object based on the time that the ultrasonic waves propagate through space.

[Background technology] Generally, in an ultrasonic range finder, when the ultrasonic waves sent out from the range finder body are reflected by an object, the reflected waves are detected, and the detection method is calculated based on the time difference between sending out the ultrasonic waves and receiving the reflected waves. to detect the distance to the object. However, since the surface of an object usually has unevenness, the ultrasonic wave will be reflected diffusely, causing multiple reflections and making it impossible to measure the accurate distance. The problem is that ultrasonic waves are attenuated, making it impossible to measure very large distances.

[Objective of the Invention J The present invention has been made in view of the above-mentioned points, and its main purpose is to provide an ultrasonic wave that enables distance measurement regardless of the unevenness of the surface of an object. Another object of the present invention is to provide an ultrasonic distance meter capable of measuring relatively large distances.

[Disclosure of the Invention] The present invention includes a repeater that is detachably attached to an object and a rangefinder main body that is spaced apart from the repeater,
The distance meter body is the first one that sends out transmission signals toward the repeater.
a first receiving means that receives a return signal sent back from the repeater; and a calculation that calculates the distance to the repeater based on the time difference between sending the transmission signal and receiving the return signal. and distance display means for displaying the distance calculated by the arithmetic means, the repeater includes second receiving means for receiving the transmission signal, and generating and transmitting a return signal when the transmission signal is received. Since at least one of the transmission signal and the return signal is an ultrasonic wave, the distance can be accurately measured regardless of the shape of the object surface, and the distance can be measured over a relatively large distance. An ultrasonic distance meter capable of performing measurements is disclosed.

(Embodiment 1) As shown in FIG. 1, the present invention basically provides a repeater 2 that is detachably attached to the surface of an object 3 whose distance is to be measured, and a repeater 2 that is separated from the repeater 2. It is composed of a distance meter main body 1 arranged therein.

As shown in FIG. 2, the distance meter main body 1 includes a transmitting means 10 that intermittently sends out a transmission signal that is an ultrasonic pulse, and a return means that is an ultrasonic pulse that is sent back from the repeater 2 based on the transmission signal. Receiving means 20 for receiving signals and transmitting means 10
After the transmission signal is sent from p!, the return signal is sent to the receiver p! i
20, and distance display means 4o for displaying the distance calculated by the calculating means 30.

The transmitting means 10 includes an integrating circuit 11 that sets the transmission interval of ultrasonic pulses, a first monostable multivibrator (hereinafter referred to as monostable multi) 12, and a rise of the output of the first monostable multivibrator 12. The second monostable multi 13 generates a pulse corresponding to the pulse of the ultrasonic pulse as a signal, and the second monostable multi 13 changes the frequency of the ultrasonic pulse during the period when the pulse is output. An oscillation circuit 14 that outputs high frequencies of equal frequency, and an oscillation circuit 1
The ultrasonic transducer includes a driver circuit 15 that amplifies the output level of the ultrasonic transducer 4 to a level capable of driving an ultrasonic transducer, and a transducer 5 that is an ultrasonic transducer. As a result, when the power is turned on, the integrating circuit 11 starts integrating with the power supply voltage input at a predetermined time constant, and when the output level of the integrating circuit 11 passes the input threshold of the first monostable multi 12, the A pulse with a predetermined time width is output from one monostable multi-channel 12. The integration circuit 11 continues to perform integration while the pulse from the first monostable multi 12 is being output, and is reset by the fall of the pulse from the monostable multi 12. .

After being reset, V8 starts again, so this operation continues, and the first monostable multi 12 generates pulses at a predetermined period, and the generation period of this pulse is the same as that of the ultrasonic pulse. This is the transmission interval. This pulse is input to the second monostable multi 13 which detects the rising edge of the pulse and outputs a pulse for a sufficiently shorter time than the pulse output from the first monostable multi 12. Oscillation circuit 1
4 is designed so that an oscillation output can be obtained only during the period when the output pulse of the second monostable multi 13 is being sent.
Therefore, as the output of the oscillation circuit 14, high frequency pulses are obtained at time intervals corresponding to the output pulses of the first monostable multi 12 and during times corresponding to the output pulses of the second monostable multi 13.

By raising the level of this high-frequency pulse to the driving level of the ultrasonic transducer via the driver circuit 15 and applying it to the transducer 5, the transducer 5 sends out an ultrasonic pulse corresponding to the high-frequency pulse. .

The receiving means 20 includes a transducer 5, an amplification circuit 21 that amplifies the received signal received by the transducer 5, and an amplifier circuit 2.
A tuning amplification circuit 22 that passes only a signal of a predetermined frequency component out of the output of the tuning amplification circuit 22, and a detection circuit 2 that extracts only the envelope component excluding high frequency components from the output of the tuning amplification circuit 22.
3, a determination circuit 24 that outputs a detection signal when the output level of the detection circuit 23 is equal to or higher than a predetermined level and is obtained within a predetermined receivable period; and a date setting circuit 25 that sets the receivable period of the determination circuit 24 based on the date and time. The date setting circuit 25 is a circuit that generates a pulse that rises after a predetermined time delay from the rise of the output of the first monostable multi 12 based on the output of the first monostable multi 12 and has a duration of a predetermined time. The period during which pulses are output from the setting circuit 25 is the receivable period, and distance measurement is possible only when a reflected wave is received during this period.

It becomes.

The calculation means 30 is a calculation circuit 31 composed of a counter or the like.
The output of the judgment circuit 24 and the output of the second monostable multi 13 are input, and the reception detection signal output from the judgment circuit 24 is determined from the rise of the output of the second monostable multi 13. The time until the rise is measured, and the distance corresponding to the time difference is calculated. That is, if the outside temperature is Th degree Celsius, the sound speed Vs is expressed as (3310, 6 Th), so the time from when the ultrasonic pulse is sent out by the transmitting means 10 until it is received by the receiving means 20 is If Tm, then the calculation is performed assuming that the distance Ds at that time is expressed by the following equation.

Note that in order to correct the outside temperature, it is sufficient to appropriately provide a temperature measuring means for measuring the outside temperature and to perform the above calculation based on the output of the temperature measuring means.

The output of the arithmetic circuit 31 is input to a distance display circuit 41 which is a distance display means 40, and the result of the arithmetic operation in the arithmetic circuit 31 is displayed.

On the other hand, the repeater 2 includes a receiving means 50 that receives the transmission signal sent from the rangefinder main body 1, and a transmitting means 60 that sends a return signal toward the rangefinder main body 1 when the transmission signal is received.
Equipped with.

The receiving means 50 includes a transducer 6 that is an ultrasonic transducer, an amplifying circuit 51 that amplifies the received signal received by the transducer 6, and a signal of a predetermined frequency component among the outputs of the amplifying circuit 51. a tuning amplification circuit 52 that only allows the signal to pass through; a detection circuit 53 that extracts only the envelope #i acid component excluding high frequency components from the output of the tuning amplification circuit 52; A determination circuit 54 that allows the received signal to pass if it is obtained outside the reception prohibited period.
and a date setting circuit 55 for setting the reception prohibition period of the determination circuit 54 based on the output of the first monostable multi 62 of the transmitting means 60, which will be described later. The pulse width determination circuit 56 outputs a detection signal when the pulse width is equal to or longer than the middle time. The date setting circuit 55 is configured based on the output of the first monostable multi 62 to prohibit the received signal from passing through the determination circuit 54 at least during the period in which the output of the first monostable multi 62 is rising. This is a circuit that generates pulses. In other words, the period during which the pulse is output from the date setting circuit 55 is the reception prohibited period.

The transmitting means '60 includes a switching circuit 61 which is controlled to open and close by the output of the pulse width determining circuit 56 and which shapes the waveform of the output of the pulse width determining circuit 56, and a switching circuit 61 which is controlled to open and close by the output of the pulse width determining circuit 56, and a switching circuit 61 which uses the rising edge of the output of the switching circuit 61 as a trigger signal to transmit data during a predetermined period of time. Monostable multi 62 that generates pulses and monostable multi 62
an oscillation circuit 63 that outputs a high frequency wave having a frequency equal to the frequency of the ultrasonic pulse during a period when the pulse is output from the ultrasonic pulse;
It is composed of a driver circuit 64 that raises the output level of the oscillation circuit 63 to a level capable of driving an ultrasonic transducer, and a transducer 6 that is an ultrasonic transducer. Here, the output frequency of the oscillation circuit 63 is set to the same frequency as the output frequency of the oscillation circuit 14 of the rangefinder body 1. When the transmission signal transmitted from the rangefinder body 1 is received by the receiving means 50 and a detection signal is output from the pulse determination circuit 56, the signal is input to the monostable multi 62, and the monostable multi 62 A short pulse is output from the

Since the oscillation circuit 63 is configured to provide an oscillation output only during the period when the output pulse of the monostable multi 62 is being sent, the output of the oscillation circuit 63 is the monostable multi output immediately after the transmission signal is received. A high frequency pulse with a time width corresponding to 62 output pulses can be obtained. By applying this high-frequency pulse to the transducer 6 via the driver circuit 64, the transducer 6 sends out a return signal that is an ultrasonic pulse corresponding to the high-frequency pulse. During the period in which the return signal is being output, an output pulse is being sent from the date setting circuit 55, so this period becomes a reception prohibition period, and looping from the transmitting means 60 to the receiving means 50 is prevented, and the repeater 2 is one that does not self-oscillate.

As shown in FIGS. 3 and 4, the housing 70 of the rangefinder main body 1 is box-shaped, and the transducer 5 has a horn 71 attached to the front thereof to provide strong directivity.
The switch handle 72 of the power switch 76 is exposed, and a display 73 such as a light emitting diode display connected to the distance display circuit 41 is also exposed on the side of the Haunonga 0. Inside the housing 70, a printed circuit board 74 on which the above circuit is mounted, a battery 75 serving as a power source, and the like are installed.

As shown in FIGS. 5 and 6, the housing 80 of the repeater 2 has a thin box-like shape at the front and rear, and the transducer 6 has a horn 81 attached to its front surface to provide strong directivity. and the switch handle 82 of the power switch 86 are exposed. (g) Inside the puffer fish 80, a printed circuit board 83 on which the above circuit is mounted, a battery 84 serving as a power source, etc. are installed.

Appropriate attachment means 85 such as magnets are provided on the rear surface of the housing 80.
is provided so that the repeater 2 can be detachably attached to a target object 3 for measuring distance.

(Operation) The operation will be explained below based on FIG. 7. Oh, fj
In the IJ7 diagram, S, -S,. indicates the signal in the portion indicated by the corresponding symbol in FIG. First, when the power is turned on, as shown in FIG. 1
2 is triggered, and a relatively long pulse 11 is output as shown in FIG. 7(b). The integration circuit 11 is reset by the fall of this pulse, and the output level increases again. Pulses will be sent out at predetermined intervals. In other words, the integrator circuit 11 and the first monostable multi 1
2 constitute an astable multivibrator. The second monostable multi 13 uses the rising edge of the output of the first monostable multi 12 as a trigger signal, and as shown in FIG.
) outputs pulses of relatively short duration. In other words, in the repetition period of the pulse output from the first monostable multi 12, the second monostable multi 13 outputs a short time rl.
The J pulse will be output. A high frequency wave is output from the oscillation circuit 14 during the period when this pulse is output. In other words, high-frequency pulses are obtained intermittently at regular intervals. As shown in FIG. 7(d), the level of this high frequency pulse is raised by the driver circuit 15, and then converted into an ultrasonic pulse by the transducer 5 and emitted. As described above, intermittently generated ultrasonic pulses are obtained and sent out as transmission signals.

The transmission signal outputted from the transmitting means 10 in this way is received by the transducer 6 of the repeater 2, amplified by the middle circuit 51, unnecessary frequency components are removed by the tuned amplification circuit 52, and then the detection circuit 53, and the envelope component of the received signal is extracted as shown in FIG. 7(f). Detection circuit 5
When the output signal of No. 3 exceeds a predetermined reference value Vref set in the determination circuit 54, it passes through the determination circuit 54, and if this pulse width is greater than or equal to the predetermined value, a detection signal is output from the pulse-in-pulse determination circuit 56. Based on this, the switching circuit 61 is opened, and the rising edge 9 of the switching circuit 61 becomes a signal for the monostable multi 62, and a pulse during a predetermined time is output. During the period when this pulse is output, an oscillation output is obtained from the oscillation circuit 63, and this oscillation output is applied to the transducer 6 via the driver circuit 64, thereby being converted into an ultrasonic pulse and emitted. In this way, in repeater 2,
When the transmission signal is received, it sends out an ultrasonic pulse as a return signal. Here, during the period when the monostable multi 62 is outputting a pulse, the determination circuit 54 is prohibited from receiving data by the output of the date setting circuit 55.
During the period when the return signal is being transmitted from the transmitting means 60, no reception detection signal is obtained from the receiving means 50, and it is possible to prevent the transmitting means 60 from malfunctioning due to a signal that goes around from the transmitting means 60 to the receiving means 50. It's pleasing.

The return signal sent back from the repeater 2 is received by the transducer 5 of the rangefinder body 1, amplified by the middle circuit 21, and then unnecessary frequency components are removed by the tuning amplification circuit 22, as shown in FIG. A signal like (i) is obtained. This signal is detected by the detection circuit 23 and input to the determination circuit 24. As shown in FIG. 7(e), the N-leg circuit 24 receives a pulse for setting the receivable period T2 from the date setting circuit 25, and when the output level of the detection circuit 23 is above a predetermined level and If the level is reached during the receivable period, a detection signal is output. Here, the pulse output from the date setting circuit 25 rises with a delay of a predetermined time T after the output of the first monostable multi 12 rises, and the measurement distance is determined by the delay time T and pulse width T2. limits are set. When a detection signal as shown in FIG. 7(j) is obtained from the determination circuit 24, the arithmetic circuit 31 calculates the above-mentioned signal based on the time difference Tm between the rise of the output of the second monostable multi 13 and the rise of the detection signal. By performing such calculations, the distance DS to the repeater 2 is calculated. The calculated distance is input to the distance fi display circuit 41, and the value is displayed on the display 73.

(Example 2) In Example 1, an example was shown in which the transmission signal and the return signal were ultrasonic pulses with the same frequency, but in this example, an example was shown in which both signals were ultrasonic pulses with different frequencies. .

Since the transmission signal and the return signal have different frequencies in the distance meter main body 1 and the repeater 2, different transducers are used for transmitting and receiving ultrasonic waves. That is, in the first embodiment, transmission and reception were performed by one transducer 5, 6, but as shown in the diagram tAa, here, the transducer 16.6 is used for transmission and reception.
5 and the delivery device 26+57. For example, if a 20 KHz ultrasonic wave is used as a transmission signal, the transmitter 16 and the receiver 57 each use an ultrasonic vibrator with a natural frequency of 20 KHz, and a 40 KHz ultrasonic wave is used as a return signal. Therefore, the transmitter 65 and the receiver 26 each use a sadonic wave oscillator with a natural frequency of 40 KHz.

The circuit configuration of the distance meter main body 1 is basically the same as that of the first embodiment, except that the transmitter 16 and the transfer device 26 are separated. In the repeater 2, the pulse determination circuit 56 is omitted, and instead, when an output is obtained from the determination circuit 54, the switching circuit 91 is closed by the output, and a light emitting light is turned on when the switching circuit 91 is in a conductive state. A reception confirmation display means 9 constituted by a reception indicator 92 such as a diode is provided.

That is, if the repeater 2 receives the transmission signal sent from the rangefinder body 1 and the level is above a predetermined level,
The reception indicator 92 is turned on to indicate that the transmission signal has been received. Here, since the receiving frequency and the transmitting frequency of the repeater 2 are different, the ultrasonic waves sent out from the transmitter 65 do not go around to the transfer device 57, and the date setting as in the first embodiment is not possible. The circuit 55 is no longer necessary.

As shown in FIG. 9, a horn 17.2 is provided on the front surface of the housing 70 of the rangefinder body 1 to provide strong directivity.
The transmitter 16 and the receiver 26 to which numbers 7 are attached, respectively, and the switch handle 72 of the power switch are exposed, and a display 73 is exposed on the side. On the front surface of the housing 80 of the repeater 2, as shown in FIG. 92 is exposed, and the switch handle 82 of the power switch is exposed on the side.

With the above configuration, the transmitted signal and the returned signal are completely separated, and interference is less likely to occur, making it possible to measure distance more accurately. Furthermore, when the repeater 2 receives the transmission signal sent from the rangefinder main body 1, it lights up the reception indicator 92, so it is possible to check whether the repeater 2 is operating while the rangefinder main body 1 is being operated. It has the advantage of being easy to operate. Although a light emitting device such as a light emitting diode is used as the reception indicator 92, it may be replaced with a sounding device such as a buzzer.

(Embodiment 3) This embodiment shows an example in which a light beam is used as a transmission signal and an ultrasonic wave is used as a return signal.

In this embodiment, since the return signal is an ultrasonic wave, the receiving means 20 of the rangefinder main body 1 and the transmitting means 60 of the repeater 2 have the same configuration as in the first embodiment.

As shown in FIG. 11, the transmitting means 10 of the rangefinder main body 1 is an astable multivibrator (hereinafter abbreviated as astable multivibrator) that outputs a pulse having a relatively long period of time to set a transmission interval. 18, a monostable multi 13 that outputs a pulse with a relatively short duration using the rising edge of the output pulse of the astable multi 18 as a tri-signal, and a floodlight drive that converts the output of the monostable multi 13 to a predetermined level. It is composed of a circuit 19 and a light projector 7 such as a light emitting diode that blinks based on the output of the projector driving circuit 19. Therefore, the projector 7 lights up at the cycle of the pulses output from the astable multi 18, and a light beam as a transmission signal is output. Although the astable multi 18 is used here to set the transmission interval, the transmission interval may also be set by combining the integrating circuit 11 and the monostable multi 12 as in the above two embodiments. .

The receiver Pi 60 of the repeater 2 is composed of a photoreceiver 8 such as a photodiode and an amplification circuit 51 that amplifies the output of the photoreceiver 8. The output of the amplifying circuit 51 is input to the switching circuit 61, and when the light beam emitted from the emitter 7 is received by the light receiver 8, the switching circuit 61 of the transmitting means 60 is turned on, and the transmitter of the transmitting means 60 is turned on. 65 outputs an ultrasonic wave as a return signal.

As shown in FIG. 12, the front surface of the housing 70 of the rangefinder main body 1 includes a delivery device 26 to which a horn 27 is attached, a floodlight 7, and a switch handle 7 of a power switch 76.
2 are exposed, and a display 73 is exposed on the side. Furthermore, as shown in FIG. 13, inside the Haunonga 0, a printed circuit board [74 with a circuit portion mounted thereon, a battery 75 as a power source, and the like are stored.

On the other hand, at the front of the housing 80 of the repeater 2, as shown in FIG. There is. Further, as shown in FIG. 15, inside the housing 80, a printed circuit board 83 on which a circuit part is mounted, a battery 84 serving as a power source, and the like are installed.

(Operation) The operation will be explained below based on FIG. 16. In addition, the first
Symbols R1 to R+3 in FIG. 6 indicate signals of corresponding parts in FIG. 11. First, when the power is turned on, astable multi 1
8 oscillates for a predetermined time width T, as shown in FIG. 16(a).
pulse is generated. The monostable multi 13 uses the rising edge of this pulse as a tri-signal to generate a pulse having a relatively short time width T2, as shown in FIG. 16(b).

This pulse is input to the light emitter drive circuit 19, and a pulse as shown in FIG. A light pulse with T2 is generated. This optical pulse is sent toward the repeater 2 as a transmission signal.

In the repeater 2, the transmitted signal is detected by the optical receiver 8. When the optical pulse is received by the optical receiver 8, FIG. 16(d)
As shown in FIG. 16(f), the optical pulse is converted into a corresponding electrical signal, amplified by an amplification circuit 64 as shown in FIG. 16(e), and then waveform-shaped by a switching circuit 61 as shown in FIG. 16(f). be done. The rise of the output of the switching circuit 61 is a signal from the monostable multi 62, and the monostable multi 62
A pulse having a predetermined time width T3 as shown in FIG. 16(g) is outputted from. During the period when this pulse is being output, the oscillation circuit 63 oscillates and outputs a high frequency pulse like @161J(h), which is amplified by the driver circuit 64 as shown in FIG. 16(i). The transmitter 65 sends out an ultrasonic pulse as a return signal.

The ultrasonic pulse is received by the receiving wave 526 of the range finder body 1,
As shown in FIG. 16(j), when the unnecessary frequency component is amplified by the zero-order amplifying circuit 21 and removed by the tuning term intermediate circuit 22, which is converted into a corresponding electric signal, the signal is converted into a corresponding electrical signal. A signal like this is obtained, which is further detected as shown in FIG. 16 (1) and input to the judgment circuit 24.

When a signal of a predetermined level or higher is input from the detection circuit 23 during a predetermined receivable period set by the setting circuit 25, a detection signal is output as shown in FIG. When input to the arithmetic circuit 31
Then, the distance to the repeater 2 is calculated based on the time difference Tm from the rise of the monostable multi 13 to the rise of the reception detection signal. Here, since the transmission signal is light and the return signal is a sound wave, the delivery time to the repeater 2 can be ignored for the transmission signal, and the above time difference Tl11 is the return signal from the repeater 2 to the distance meter. Since it can be considered that this is the time when the signal is delivered to the main body 1, the distance Ds between the rangefinder main body 1 and the repeater 2 is given by the following formula.

Ds=(331+0.6 Th)XTa+However, Th
is the outside temperature, measured by suitable temperature measuring means,
The signal is input to the arithmetic circuit 31.

As described above, the distance calculated by the arithmetic circuit 31 is input to the distance display circuit 41, and the distance is displayed on the display 73.

As described above, the transmitted signal and the returned signal are completely separated without interference, so there is an advantage that no malfunction occurs and accurate measurements can be performed.

Note that in order to prevent the influence of external light on the transmission signal, a method such as applying appropriate modulation to the transmission signal may be used. Furthermore, although here the transmission signal is light and the return signal is ultrasonic wave, they may be reversed.

(Embodiment 5) In this embodiment, the delay time of signal processing within the repeater 2 is corrected to obtain a more accurate distance. In the main body 1, a third monostable multi 28 is inserted between the second monostable multi 13 and the arithmetic circuit 31 as a correction means.

In other words, if repeater 2 performs pulse detection during internal processing from receiving the transmission signal to sending the return signal, a non-negligible time delay will occur. On the other hand, since the transducer 6 of the repeater 2 is disposed above the surface of the object 3, the measured value is smaller than the true value. This situation is plS1
This is shown in Figure 8. In other words, if the transmission signal is received by the repeater 2 as shown in FIG. 18(c), and the return signal is output as shown in FIG.
There will be a delay. If the time for the ultrasonic waves to travel the distance corresponding to the thickness of the repeater 2 is Td, and the distance between the rangefinder body 1 and the surface of the object 3 is the true time for the ultrasonic waves to travel back and forth, 2Tt, then tIS18 diagram ( When a transmission signal is sent from the rangefinder body 1 to the repeater 2 as shown in a), the time required for the transmission signal to be delivered to the repeater 2 is (Tt) as shown in FIG. 18(c). -Td), and the time it takes for the return signal to be delivered from the repeater 2 to the rangefinder body 1 is also shown in Figure #18 (e
) will be the same time. The time required from sending out the transmission signal from the rangefinder main body 1 to receiving the return signal is calculated by adding the internal processing time Ti of the repeater 2 to this time, which is 2.
(T t - Td) +T i, that is, the error is Ti
-2Td.

However, since the ratio of the internal processing time of repeater 2 is generally large as an error factor, Ti>2Td, and the above 2.
If errors in the measured value due to causes are subtracted, the measured value will be larger than the true value. Therefore, the true value can be obtained by delaying the calculation start time of the calculation circuit 31 by the time (Ti 2Td) from the sending time of the ultrasonic pulse. Here, time (Ti-27cl
) is a nearly constant value in one system, so the second
This time (
If a third monostable multi 28 is inserted to create a signal (Ti-2Td), the calculation gIl? of the calculation circuit 31 is inserted. ! The start time is set to a predetermined time (Ti-2
This can be achieved by delaying by Td). In the manner described above, the error is corrected and the true value is determined.

In addition, although the above-mentioned example described the case where both the transmission signal and the return signal are eyebrow sound waves, it goes without saying that if one of them is light, the correction value will be (Ti-Td). Also, Ti<2Td.

In such a system, the output of the third monostable multi 28 may be used to delay the stop time of the arithmetic circuit 31 by the time (2Td-Ti).

(Example 6) In Example 6, as shown in FIG.
77 is the display 7 on the side of Haunonga 0 of the rangefinder body 1.
3, and the calculator 77 is capable of performing operations such as addition, subtraction, multiplication, and division, and is equivalent to an ordinary electronic desktop calculator having a memory. However, as shown in FIG. 20, if repeaters 2 are installed at multiple locations on the walls of the room and the distance to each wall is measured, the area of the workstation shop can be determined by calculating with the calculator 77, This allows you to instantly know the volume, which is very convenient.

[Effects of the Invention] As described above, the present invention includes a repeater that is detachably attached to an object and a rangefinder body that is disposed apart from the repeater. a first transmitting means that sends a transmission signal to a repeater; a first receiving means that receives a return signal sent back from the repeater; and a time difference between sending the transmission signal and receiving the return signal. and distance display means for displaying the distance calculated by the calculation means, and the repeater has second receiving means for receiving the transmission signal, and a second transmitting means that creates and transmits a return signal when received, and since at least one of the transmission signal and the return signal is an ultrasonic wave, by using a repeater, it is possible to transmit a signal to the object surface. It has the advantage that accurate measurements can be made regardless of the presence of irregularities. In addition, since the repeater has a transmitting means, the rangefinder itself can receive the return signal sent from the repeater rather than the reflected wave, so the return signal can reach a relatively short distance. , has the advantage of being able to measure relatively long distances.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram showing the usage state of the present invention, Fig. 2 is a block diagram showing Embodiment 1 of the invention, Fig. 3 is an external perspective view of the rangefinder body used in the above, and Fig. 4 is 5 is an external perspective view of the repeater used in the above, FIG. 6 is a longitudinal sectional view of the repeater used in the above, and FIG. 7 is the same as the 2nd figure. Operation explanatory diagram showing the signals of each part inside,
FIG. 8 is a block diagram showing a second embodiment of the present invention, FIG. 9 is an external perspective view of a rangefinder body used in the same, FIG. 10 is an external perspective view of a repeater used in the same, and FIG. A block diagram showing Embodiment 3 of the present invention, Fig. 12 is an external perspective view of the rangefinder body used in the above, Fig. 13 is a vertical sectional view of the rangefinder main body used in the above, and Fig. 114 is used in the same. 15 is a vertical sectional view of the repeater used in the same manner as above, FIG. 16 is an operation explanatory diagram showing the signals of each part in FIG. 11, and FIG. FIG. 18 is a block diagram showing the fourth embodiment, FIG. 18 is an explanatory diagram of the same operation as above, FIG. 19 is an external perspective view showing the fifth embodiment of the present invention, and FIG. 20 is an explanatory diagram of the operation showing one usage state of the same. . 1 is a distance meter body, 2 is a repeater, 3 is an object, 9 is a reception confirmation display means, 10 is a transmitting means, 20 is a receiving means, 30 is a calculation means, 40 is a distance display means, 50 is a receiving means, 60 is a The transmitting means 77 is a calculator. Agent Patent Attorney Ishi 1) Ai 7*7 Figure 9 Figure 101g Figure 16

Claims (6)

[Claims] (1) It has a repeater that is detachably attached to an object and a rangefinder main body that is arranged separately from the repeater, and the rangefinder main body has a first transmitter that sends a transmission signal toward the repeater. a first receiving means that receives a return signal sent back from the repeater; and a calculation that calculates the distance to the repeater based on the time difference between sending the transmission signal and receiving the return signal. and distance display means for displaying the distance calculated by the arithmetic means, the repeater includes second receiving means for receiving the transmission signal, and generating and transmitting a return signal when the transmission signal is received. an ultrasonic range finder comprising a second transmitting means, wherein at least one of the transmission signal and the return signal is an ultrasonic wave. (2) The ultrasonic distance meter according to claim 1, wherein the transmission signal and the return signal are both ultrasonic waves and have different frequencies. (3) The ultrasonic distance meter according to claim 1, wherein the transmission signal is light and the return signal is an ultrasonic wave. (4) The calculation means comprises a correction means for correcting a delay time from when the repeater receives the transmission signal until it sends out the return signal, as set forth in claim 1. Ultrasonic distance meter. (5) The ultrasonic distance according to claim 1, wherein the repeater is provided with a reception confirmation display means for displaying that the transmission signal has been received when the transmission signal is received. Total. (6) The ultrasonic distance meter according to claim 1, wherein the distance meter main body includes a calculator.