JPH09251006A - Portable strength judging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate carrying and to perform the judgment of the strength degree of a body under inspection very easily. SOLUTION: When the signal of the vibrating sound of a piece of wood 20, which is captured by a compact microphone 40, is converted into the digital signal by an A/D converting means 42, a naturalfrequency judging part 43 obtains the natural-frequency value of the wood 20 based on the digital signal. A Young's modulus judging part 44 obtains the Young's modulus based on the length data obtained by the operation by the combination of a dial switch 14 and a set switch 15, the kind data obtained by the operation in combination of the set switch 15 and a selecting switch 16 and the natural frequency value from the natural-frequency judging part 43. When, a strength-degree judging part 45 judges the strength degree based on the Young's modulus, a display part 13, which is the output means, outputs the result of the judgement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable strength judging device for judging the strength class of a test object such as wood by a method of gently hitting the test object with a hammer or the like and exciting the test object with vibration.

[0002]

2. Description of the Related Art For example, it is known that the mechanical strength of wood can be determined by utilizing the correlation with the frequency of the tapping sound generated when the wood is hit.

If the size of the object is constant, the frequency is
The higher the hardness, the lower the softness. If the hardness is constant,
The larger the size of the object is, the lower it is, and the smaller it is, the higher it is. Therefore, by utilizing such resonance phenomenon, it is possible to measure the pitch of the sound (frequency of vibration) determined by the size and elastic modulus of the wood, and conversely from the theory of vibration, it is possible to measure the elastic modulus. It is possible to determine the mechanical strength of the.

As a method for determining the mechanical strength of such wood, for example, in Japanese Examined Patent Publication No. 6-78974, the cutoff frequency of the filter is automatically set according to the type and size of the test piece. A method has been disclosed in which the function is incorporated into a computer, the cutoff frequency of the filter is determined from the statistical lower limit value and the theoretical vibration formula in consideration of the Young's modulus of the material, and the cutoff frequency of the low-pass filter is automatically set via the computer. There is.

According to such a method, even a person who has no knowledge of measurement can easily handle the measurement, but since the weight must be detected by the load sensor system, the whole system is large. Not only that, but also because it is necessary to carry the wood to the load sensor system at each measurement, the measurement becomes complicated.

Further, for example, in Japanese Unexamined Patent Publication No. 6-18388, the wood mouth surface is struck by the hitting means, the generated frequency is detected by the frequency sensing means, and the Young's modulus of the wood is based on this frequency. A method for determining the grade of wood by determining is disclosed.

According to such a method, since the Young's modulus of the wood can be obtained only by striking the mouth of the wood, the grade of the beam girder material or the like which is generally difficult to bend can be easily discriminated. Since the wood support part, the hitting means and the frequency sensing means are installed in the frame, not only the whole system becomes large-scale as above, but also it is necessary to carry the wood to the wood support part every time it is discriminated. Therefore, the discrimination is complicated.

[0008]

As described above, in the case where the mechanical strength of wood is judged by the above-mentioned conventional method, not only the whole system becomes large-scale, but also the measurement or judgment is performed. Since it is necessary to carry the wood to the load sensor system or the wood support section every time, the measurement or judgment is complicated.

The present invention has been made in consideration of such circumstances, and provides a portable strength judging device which can be carried easily and can judge the strength class of a subject extremely easily. The purpose is to

[0010]

In order to achieve the above-mentioned object, the present invention detects a vibration sound generated when a subject is hit by a small microphone incorporated in the apparatus body, and based on this vibration sound A portable strength determination device for performing strength determination of the subject, wherein the device body is an A / D converter for converting a signal of a vibration sound generated by the subject obtained through the small microphone into a digital signal. Means, a natural vibration determining means for obtaining a natural vibration value of the subject from a signal obtained by A / D conversion, a length data input means for inputting length data of the subject, and a length data input means for the subject. Type data input means for inputting type data according to type, Young's coefficient determination means for obtaining Young's coefficient of the subject from the natural vibration value, the length data and the type data, Based on the Young's modulus obtained by the coding coefficient determining means, a strength grade determining means for determining the strength grade of the subject and an output means for outputting the determination result determined by the strength grade determining means are incorporated. It is characterized by

[0011]

In the portable strength judging device of the present invention, when the vibration sound signal generated when a subject is hit by a small microphone is converted into a digital signal by the A / D converting means, the natural vibration judging means The natural vibration value of the subject is obtained based on the digital signal.

Then, the Young's coefficient determining means obtains the Young's coefficient based on the length data from the length data inputting means, the type data from the type data inputting means, and the natural vibration value from the natural vibration judging means. When the strength class judging means judges the strength class based on the Young's modulus, the output means outputs the judgment result.

Therefore, since the apparatus main body includes a small microphone and various functions for obtaining the strength grade determination result are incorporated, the apparatus can be made compact and lightweight, and is easy to carry.

Further, in the case of judging the strength class of the object, the length data and the type data of the object to be judged are inputted in advance, and a small microphone is pressed against the object to hit the object. Since it is only necessary to take in the vibration sound generated at the time, and it is not necessary to carry the subject to the load sensor system or the wood supporting portion as in the conventional case, the determination work becomes extremely easy.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of a portable strength determination device of the present invention. A power switch 1 for turning on / off a power source is provided on an upper surface side of a device body 10.
1 is provided. A microphone pad 12 is provided on the upper side of the front side of the apparatus main body 10 so as to prevent ambient noise from being captured by pressing the microphone pad 12 against the mouth of the wood 20, which is an object to be described later.

A display unit 13 is provided in the middle of the front side of the apparatus main body 10 to display an input instruction of length data and tree species data, which will be described later, which is necessary for the determination, and a natural vibration of the measured wood 20. The number is displayed and the strength grade judgment result is displayed.

The dial switch 14, the set switch 15, and the selection switch 1 are provided on the lower side of the front side of the apparatus body 10.
6 and a battery monitoring lamp 17 are provided. Then, the length data of the wood 20 can be input by a combination of the dial switch 14 and the set switch 15. Further, the tree species data can be input by a combination of the set switch 15 and the selection switch 16.

FIG. 2 shows the internal structure of the apparatus main body 10. As shown in the figure, the natural frequency from the ostium of the wood 20 taken in by the small microphone 40 is amplified to a predetermined level by the amplification unit 41, and then A
When converted to a digital signal by the / D conversion unit 42, the natural frequency determination unit 43 obtains the natural frequency.

The length data output unit 46 outputs length data based on the input by the combination of the dial switch 14 and the set switch 15 described above. The tree species data output unit 47 is the set switch 1 described above.
5 and the selection switch 16 are combined to output the tree species data.

Here, the length data and the tree species data output from the length data output unit 46 and the tree species data output unit 47 are kept until the new data is input by the combination of the respective switches. It is held in the output unit 46 and the tree species data output unit 47.

As shown in FIG. 5, the tree species data output from the tree species data output unit 47 are provided corresponding to, for example, cedar, cypress, and bay pine, 1a to 3a.
It is classified data shown by b. This division data 1a-3b
The data includes data indicating the type of product, data indicating the density ρ, water, shape (logs, timbers, etc.), morphology (bark, etc.), and the like.

The Young's modulus determining unit 44 includes the length data output from the length data output unit 46, the tree type data output from the tree type data output unit 47, and the natural frequency determining unit 4
The Young's modulus is obtained based on the data indicating the natural frequency output from No. 3.

Here, the arithmetic expression in the Young's modulus determining unit 44 is E (Young's modulus) = 4 · L ² · ρ · _fr ² where L is length, ρ is density, and _fr is natural frequency. is there.
The strength class determination unit 45 determines the strength of the wood 20 based on the Young's system numerical value obtained by the Young's coefficient determination unit 44, and the determined strength is displayed by the display unit 13.

That is, as shown in FIG. 6, the strength is divided into ranks of, for example, 1 to 5, and the contents indicated by (rank display) in FIG.

Next, the operation of the portable strength determination device having the above-mentioned structure will be described with reference to FIGS. 3 and 4. First, with the power switch 11 turned on, length data and tree species data are input (steps 401, 40).
2). At the time of inputting these data, when inputting the tree species data, an input operation is performed by a combination of the set switch 15 and the selection switch 16.

That is, when the set switch 15 is operated, the display content of the display unit 13 is in a standby state for inputting tree species data. By the way, every time the set switch 15 is operated, the display content of the display unit 13 is switched between the tree species data input standby state and the length data input standby state.

When the selection switch 16 is operated in this state, the classification data corresponding to each applicable product type 1a to 3b shown in FIG. 5 is displayed for each operation. Therefore, for example, when the wood 20 as the subject is cedar,
By operating the selection switch 16 to display the classification data 1a and operating the set switch 15 in this state, the tree species data output unit 47 outputs the tree species data corresponding to the cedar of the wood 20.

On the other hand, when inputting the length data, the input operation is performed by the combination of the dial switch 14 and the set switch 15. That is, the set switch 15
Is operated to bring the display content of the display unit 13 into a standby state for inputting length data.

In this state, the dial switch 14 is operated to input the size of the wood 20 which is the subject. In this case, the size display displayed on the display unit 13 changes according to the rotation of the dial switch 14. Therefore, when a predetermined size is displayed, the set switch 15 is operated in this state to adjust the length. The length data is output from the data output unit 46.

After the setting of these data is completed, as shown in FIG. 3, the microphone pad 12 is lightly pressed against the surface of the wood 20. This prevents ambient noise from being taken in.

In this state, when the same portion of the wooden piece 20 is tapped slowly about three times with the sun bar 30 (step 403) (step 403), as shown in FIG. The propagating peculiar vibration wave is picked up, amplified to a predetermined level by the amplification part 41, further converted into a digital signal by the A / D conversion part 42, and then the peculiar frequency determination part 43 obtains the peculiar frequency.

Then, the Young's modulus judging section 44 outputs the data showing the natural frequency obtained by the natural frequency judging section 43 and the lengths outputted from the length data output section 46 and the tree species data output section 47. Young's modulus is calculated based on the size data and the tree species data (step 40).
4).

The arithmetic expression in the Young's modulus determining section 44 here is, as described above, E (Young's modulus) = 4 · L ² · ρ · _fr ² . When the data indicating the Young's modulus obtained by the Young's modulus determining unit 44 is output, the strength class determining unit 4
The strength of the timber 20 is determined by 5, and the determination result is displayed on the display unit 13 (steps 405 and 406).

That is, as shown in FIG. 6, the strength is divided into ranks of, for example, 1 to 5, and the contents indicated by (rank display) in FIG. Subsequently, when the strength is determined for the timbers 20 of the same type and the same length, the length data and the tree species data previously input are valid, and therefore the input setting of these data is not necessary. Similarly to the above, the judgment result is displayed on the display unit 13 by gently tapping the same portion of the wood 20 with the sun bar 30 while the microphone pad 12 is lightly pressed against the wood mouth surface.

Next, in order to determine the strength of the cypress shown in FIG. 5, as described above, the tree switch data is input by the operation of the combination of the set switch 15 and the selection switch 16, and then the dial switch 14 is pressed.
And the length data is input by the operation by the combination of the set switch 15.

Here, when the length dimension of the cypress is the same as that of the cedar determined previously, the length data is stored and the input is unnecessary. Then, after the input of these data is completed, in the same manner as above, by gently pressing the same portion of the wood 20 with the sun bar 30 about three times with the microphone pad 12 lightly pressed against the ostium of the wood 20. The determination result is displayed on the display unit 13.

By the way, also in the case of performing the strength determination for the bay pine, the strength determination is performed by the same operation procedure as above. Therefore, when the strength grade judgment of the timber 20 of the same type is performed, not only continuous judgment work is possible, but even if the kinds are different, continuous judgment can be made only by changing the data input condition. Since the work can be performed, it is possible to determine the strength class of many woods 20 in a short time.

As described above, in the present embodiment, the signal of the vibration sound generated when the wood 20 which is the object to be detected is hit by the small microphone 40 is A / D converting means which is A / D converting means. When converted into a digital signal by 42, a natural vibration judging section 43 which is a natural vibration judging means.
Calculates the natural vibration value of the wood 20 based on the digital signal.

Then, the Young's coefficient determining unit 44, which is Young's coefficient determining means, sets the length data by the operation of the combination of the dial switch 14 and the set switch 15, which are the length data inputting means, and the type data inputting means. Type data by an operation by a combination of the switch 15 and the selection switch 16 and the natural vibration determination unit 4
The Young's modulus is obtained based on the natural vibration value from No. 3, and when the strength class determination unit 45, which is the strength class determination unit, determines the strength class based on the Young coefficient, the display unit 13, which is the output unit, displays the determination result. Output.

Therefore, since the apparatus main body 10 includes the small microphone 40 and incorporates various functions for obtaining the determination result of the strength class, the apparatus main body 10 can be made small and lightweight and easy to carry. be able to.

When determining the strength class of the wooden piece 20, the length data and the type data of the wooden piece 20 to be judged are input in advance, and the small microphone 40 is used as the wooden piece 20.
Since it is only necessary to capture the vibration sound generated when the wood 20 is hit against the load sensor system and hitting the wood 20, it is not necessary to carry the subject to the load sensor system or the wood support portion as in the conventional case. The determination can be made extremely easily.

In the present embodiment, the subject is wood 2
Although the case of 0 has been described, the present invention is not limited to this, and can be applied to the determination of strength and grade strength grade of logs and resins. Further, in the present embodiment, the case where the determination result of the strength class is displayed on the display unit 13 has been described, but the determination result is not limited to the display unit 13, and the determination result may be output by printing.

[0043]

As described above, according to the portable type strength determination device of the present invention, the vibration sound signal generated when the subject is hit by the small microphone is set to A /
When converted into a digital signal by the D conversion means, the natural vibration determination means determines the natural vibration value of the subject based on the digital signal.

Then, the Young's coefficient determining means obtains the Young's coefficient based on the length data from the length data inputting means, the type data from the type data inputting means, and the natural vibration value from the natural vibration judging means. When the strength class judging means judges the strength class based on the Young's modulus, the output means outputs the judgment result.

Therefore, since the apparatus main body includes a small microphone and incorporates various functions for obtaining the determination result of the strength class, the apparatus can be made small and lightweight and easy to carry. it can.

Further, in the case of judging the strength class of the object, the length data and the type data of the object to be judged are inputted in advance, and a small microphone is pressed against the object to hit the object. It is only necessary to capture the vibration sound generated when the object is in contact, and since it is not necessary to carry the object to the load sensor system or the wood support as in the past, it is extremely easy to judge the strength class of the object. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a portable strength determination device of the present invention.

FIG. 2 is a diagram showing an internal configuration of the apparatus main body of FIG.

FIG. 3 is a diagram showing a usage state of the portable strength determination device of FIG.

FIG. 4 is a flowchart for explaining the operation of the portable strength determination device of FIG.

FIG. 5 is a diagram for explaining the operation of the portable strength determination device of FIG.

FIG. 6 is a diagram for explaining the operation of the portable strength determination device of FIG.

[Explanation of symbols]

 10 Device Main Body 11 Power Switch 12 Microphone Pad 13 Display Section 14 Dial Switch 15 Set Switch 16 Selection Switch 17 Battery Monitoring Lamp 20 Wood 40 Small Microphone 41 Amplification Section 42 A / D Converter 43 Natural Frequency Judgment Section 44 Young's Coefficient Judgment Section 45 Strength class judgment unit 46 Length data output unit 47 Tree species data output unit

Claims (1)

[Claims] 1. A portable strength determination device for detecting a vibration sound generated when a subject is hit by a small microphone incorporated in the apparatus body and determining the strength of the subject based on the vibration sound. The device body has an A / D for converting a vibration sound signal generated by the subject obtained through the small microphone into a digital signal.
Conversion means, natural vibration determination means for obtaining a natural vibration value of the subject from a signal obtained by A / D conversion, length data input means for inputting length data of the subject, and the subject Type data input means for inputting type data according to the type, Young coefficient determining means for obtaining Young's coefficient of the subject from the natural vibration value, the length data and the type data, and the Young coefficient determining means. It is characterized in that strength class judging means for judging the strength class of the subject based on the obtained Young's modulus and output means for outputting the judgment result judged by the strength class judging means are incorporated. Portable strength determination device.