JPS59178307A - Ultrasonic measuring apparatus - Google Patents

Abstract

PURPOSE:To measure the thickness or the number of sheets of superposed objects to be measured, by non-linearly compressing the receiving amplitude of a transmitted ultrasonic wave which is transmitted from one transmitting ultrasonic sensor and received by the other receiving ultrasonic after transmitted through the objects to be measured. CONSTITUTION:A transmission circuit 1 generates an electric signal applied to an ultrasonic sensor 2 for emitting an ultrasonic wave into the air and a transmission signal may be a continuous wave or a tone burst wave. Objects 3, 3', 3''... to be measured are a same kind of thin plates or sheets each having a same thickness of which the number of sheets should be counted. An ultrasonic sensor 4 for receiving the transmitted wave obtained after the ultrasonic wave emitted into the air by the transmitting ultrasonic sensor transmits the cloths 3, 3', 3''... is opposed to the cloths 3, 3', 3''... and arranged to the side opposite to the position of the ultrasonic sensor 2. A circuit 6 to be inspected performs the envelope-detection of the receiving signal amplified by a preamplifier 5. A non-linear amplifier 7 compresses the signal after detection and a subtraction circuits 8 obtains the difference of the output voltage of a reference voltage generator 9 and the output of the non-linear amplifier 7. A display device 10 displays the number of the cloths.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an ultra-high-speed measuring device for counting the number of thin plates or sheets or measuring the thickness of one or more thin plates or sheets stacked on top of each other. This relates to a sonic needle puller 1] device.

Configuration of conventional example and its problems This is a method for automatically counting the thickness of a thin plate or sheet-like object such as cloth or porous material, and the number of overlapping objects to be measured in a non-contact manner. Conventionally, thickness measurements and number of sheets were measured manually, which was slow and required a lot of attention, making it a time-consuming process.

Purpose of the Invention The present invention has been made in order to solve the above-mentioned problems of the conventional art. An object of the present invention is to provide an ultrasonic measuring device that can count the number of objects to be measured.

Structure of the Invention In order to achieve this object, the present invention arranges a pair of ultrasonic sensors facing each other so that an object to be measured such as cloth to be measured is interposed between them. After being transmitted from the transmitting ultrasonic sensor and passing through the object to be measured,
By nonlinearly compressing the reception amplitude of the transmitted ultrasound received by the other receiving ultrasonic sensor, the thickness of the object to be measured and the number of overlapping objects to be measured are measured in a non-contact manner.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a transmitting circuit that generates an electric signal to be applied to an ultrasonic sensor 2 that emits ultrasonic waves into the air, and the transmitted signal can be either a continuous wave or a tone burst wave. 3, 3', 3''... are thin plate-like or sheet-like objects of the same type and thickness to be counted, and in this example, they are cloth. The cloths do not necessarily have to be stacked closely together, and there may be gaps between each cloth.

Reference numeral 4 denotes an ultrasonic sensor for receiving the transmitted waves after the ultrasonic waves emitted into the air by the transmitting ultrasonic sensor 2 are transmitted through the cloths 3, 3', 3', etc., and the cloths 3.3
', 3'', etc., and are arranged on the side opposite to the position of the ultrasonic sensor 2. A detection circuit 7 for envelope detection is a nonlinear amplifier for compressing the signal after detection, which is a log amplifier in this embodiment.

8 is a subtraction circuit for obtaining the difference between the output voltage of the reference voltage generator 9 and the output of the log amplifier 7;
0 is an indicator that displays the number of cloths.

According to experiments conducted by the present inventor, the logarithm of the amplitude of transmitted ultrasonic waves transmitted through these cloths with respect to the number of overlapped cloths has a linear relationship as shown in Figure 2. has been confirmed. In Figure 2, the straight line I, IT
, each of different kinds of cloth, each of 100 pieces of cotton
%, 35% cotton + 65% polyester, 10% polyester
This shows the relationship obtained from the actual 1t1 theta for the number of overlapping sheets at 0%, and the ultrasonic frequency used here is 360 KHz. That is, the amount of ultrasonic attenuation in one piece of cloth differs depending on the material of the cloth, and a straight line can be obtained depending on the material of each cloth.

The linear relationship shown in FIG. 2 can be explained as follows. The thickness of a piece of cloth to be measured is to(m+)
, the attenuation constant of ultrasonic waves due to cloth is α (Neper/m)
Then, the amplitude of the transmitted ultrasonic wave after passing through one piece of cloth is AO・e−“5, where the amplitude before transmission is Ao. Therefore, after passing through n pieces of superimposed −LχtO cloth The transmitted ultrasound amplitude is AO・e υ, which corresponds to the transmitted ultrasound amplitude, assuming that the attenuation of the ultrasound in the air in the ultrasound propagation path is negligibly small compared to the attenuation of the transmitted ultrasound due to cloth. When the value obtained by taking the logarithm of the output voltage of
-・(1), and it can be seen that there is a linear relationship between the number of cloths n and the value of 7.

In order to display the number of sheets of cloth overlapped by the above-mentioned transmitted ultrasonic amplitude, if the output voltage of the reference voltage generator 9 in FIG. Just subtract V. Output voltages 7, 71 . of the subtraction circuit 8 obtained here. 7), =Es-7)=8.68nαto+Es-201
o, j9Ao - (2), and it can be seen that there is a monotonically increasing relationship with the number n of cloth. However, it is necessary to set Eo so that the value of τS becomes positive.

Next, a method of adjusting the sensitivity of the log amplifier 7 according to the type of cloth to be counted will be explained. First, when there are m pieces of superimposed cloth and the output of the subtraction circuit 8 expressed by equation (2) is V, then vm==s, 6smαto+E, -2060gAO...
...13). At this time, as shown in FIG.
= point to m)'' = sea urchin Adjust the sensitivity of the log amplifier 7. Next, when the number of superimposed cloths is n, and the output of the subtraction circuit 8 is taken as the knee, then 1) n = 8.68nαtO + E5-2o1oj9o
-=--(4), and at this time, the sensitivity of the lock amplifier 7 is adjusted so that the indicator 11 points to the scale N (N=n) of the display 10 (man). Here, if n)m, then m
may be O. In this way, when adjusting the sensitivity of the log amplifier 7 at two points on the scale of the display 10, the linear relationship between the number of cloths and the output of the log amplifier 7 is used to adjust the number of cloths that have been overlapped. The output display corresponding to the above is impressive.

FIG. 4 shows a block diagram of a second embodiment of the present invention. 1st
The same numbers are used for the same components as those in the block diagrams shown in the embodiments. In this embodiment, the subtraction circuit 8 and reference voltage generator 9 shown in FIG.
Since the output voltage of the log amplifier 7 shown by the formula is directly used as the display input to display the number of cloth, the number display scale of the display 10 in FIG. 4 is opposite to the scale in the first embodiment. The value increases in the clockwise direction.

The method of adjusting the sensitivity of the log amplifier 7 is exactly the same as in the first embodiment. In addition, in the first and second embodiments, the display device 1
It is also possible to omit the log amplifier 7 by using a logarithmic scale as the 0 sheet number display scale.

The above embodiments have been explained with respect to counting the number of pieces of cloth, but when measuring the thickness of the object to be measured, steps (3), (
4) In the equation, replace the integer values m and n that indicate the number of cloths with continuous quantities, and let the corresponding thickness be tm.

When tn, tm = mto, tn = nt.

By setting this, it is possible to apply the method used to measure the number of cloth sheets to the thickness measurement of the cloth.

In the embodiments described above, a method of measuring a thin plate-shaped or.../t-shaped object made of cloth or other porous paulownia material using aerial ultrasonic waves was explained. The same method can be used to measure the number or thickness of a plate-like or sheet-like object made of plastic, metal, or other solid that is immersed in a liquid.

Effects of the Invention - As explained above, according to the ultrasonic measuring device of the present invention, since measurement is performed using ultrasonic waves, the thickness and number of thin plate-like or sheet-like objects to be measured can be measured without contact. It is possible to measure quickly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the ultrasonic measuring device of the present invention, and FIG. 2 shows the relationship between the logarithm of the transmitted 11B sound wave amplitude and the number of objects to be measured. Figures 3 and 3 are diagrams showing the display section of the display device according to the present invention, and the fourth drawing is a block diagram showing a second embodiment of the ultrasonic meter M1+ device according to the present invention. 1... Transmission circuit, 2, 4... Ultrasonic sensor, 3゜3', 3''... Measured object, 5... Preamplifier, 6... Envelope detection Circuit, 7...-Nonlinear amplifier circuit, 8. Subtraction circuit, 9... Reference voltage generation circuit, 10
... -Indicator, 11... Indicator hand. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 2 v t '345. fp, number of sheets Figure 3 Figure 4 Figure 3'

Claims (3)

[Claims] (1) Disposed facing each other with the object to be measured in between,
Two ultrasonic sensors that transmit and receive waves (1), a transmitting circuit that gives a transmission signal to one ultrasonic sensor, and a receiver C-i (ij) that transmits and receives waves from the other ultrasonic sensor. What is claimed is: 1. An ultrasonic measuring device comprising: a non-linear circuit for non-linearly compressing the object; and a display means for displaying the thickness or number of objects to be measured based on the output of the linear circuit. (2) Patent ii characterized in that the nonlinear circuit consists of a logarithmic amplifier? #Ice range The ultrasonic measuring device described in item 1. (3) The ultrasonic measurement device according to claim 11, wherein the display means displays the result of subtracting the output voltage of the nonlinear circuit from a predetermined reference voltage.