JP2001289828A - Class discriminating device for timber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a class discriminating device for a timber capable of accurately measuring a Young's modulus. SOLUTION: A butt end of the timber W is struck by a manner 72A. Its striking sound is captured by a sound collector microphone 74. A controller 12 calculates the Young's modulus from a frequency of the sound and a mass (weight) of the timber W. Since the sound is captured by the microphone 74 having directivity, an external noise is not superposed, but the Young's modulus can be accurately measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood grade judging apparatus for judging wood by measuring the Young's modulus of the wood.

[0002]

2. Description of the Related Art Wood for building materials is generally classified according to Young's modulus (elastic modulus). As a discriminating device for classifying wood according to Young's modulus, conventionally, a load was applied to the discriminated wood, and the Young's modulus was determined from the relationship between the load and the deflection, but now, the wood is hit with a hammer, The so-called striking acoustic method for measuring the Young's modulus from the frequency of the striking sound has been used.

[0003]

However, the percussion acoustic method is inferior in measurement accuracy to the conventional method of applying a load to measure. The present inventor has studied the cause and found that the frequency cannot be measured accurately because noise is superimposed on the impact sound.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a wood grade discriminating apparatus capable of accurately measuring Young's modulus.

[0005]

According to a first aspect of the present invention, there is provided a hitting device for hitting a wood to be discriminated, and a sound collecting device for catching sound when the wood is hit by the hitting device. A device, a Young's modulus measurement device that determines the Young's modulus from the frequency of the sound captured by the sound collection device,
The technical feature of the wood grade discriminating apparatus comprising: a sound collecting microphone having directivity toward the discriminated wood side.

According to the first aspect of the present invention, since the sound collecting device is composed of a sound collecting microphone having directivity, it is possible to capture sound without superimposing external noise, and to accurately measure the Young's modulus. It becomes possible.

According to a second aspect of the present invention, in the first aspect, a hitting device for hitting the wood to be discriminated, a sound collecting device for capturing sound when the hitting wood is hit by the hitting device,
And a Young's modulus measuring device that obtains a Young's modulus from the frequency of the sound captured by the sound collecting device, wherein the sound collecting device has an opening formed on the discriminated wood side. A technical feature is that a cover made of a material and a microphone having a sound collecting portion protruding from the cover are provided.

According to the second aspect of the present invention, since the sound collecting portion of the microphone is covered with a cover made of a sound absorbing material having an opening formed on the side of the discriminated wood, the sound can be generated without superimposing external noise. As a result, the Young's modulus can be measured accurately.

According to a third aspect of the present invention, in the second aspect, at least a portion of the hitting device for hitting the discriminated wood is:
It is a technical feature that it is housed in the cover.

According to the third aspect of the present invention, the portion of the striking device that hits the wood to be discriminated and the sound collecting portion of the microphone are covered by a cover made of a sound absorbing material having an opening formed on the side of the wood to be discriminated. In addition, the sound can be captured without external noise superimposed thereon, and the Young's modulus can be accurately measured.

A fourth aspect of the invention is characterized in that, in the second aspect, the opening of the cover is arranged so as to be in contact with the wood to be discriminated.

According to the fourth aspect of the present invention, since the opening of the cover is disposed so as to be in contact with the wood to be discriminated, it is possible to capture sound without superimposing external noise and accurately measure the Young's modulus. Becomes possible.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wood grade discriminating apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG.
FIG. 2 is a plan view showing a line configuration of the wood grade discriminating apparatus according to the first embodiment. The grade discriminating device 10 includes a front-stage transport device 20 including a pair of chain rollers C for loading the wood W, a weight measuring device 30 for measuring the weight of the wood W loaded from the front-stage transport device 20, and a weight measuring device. A post-conveying device 22 comprising a pair of chain rollers C for conveying the wood W whose weight has been measured by the device 30;
Measuring device 5 for measuring the moisture of the wood W transported 2
0, Young's modulus measuring device 7 for measuring Young's modulus of wood W
Printing device 9 for printing 0 and the measured Young's modulus on wood W
0, the above-mentioned weight measuring device 30, moisture measuring device 50,
It comprises a Young's modulus measuring device 70 and a control device 12 for controlling the printing device 90.

FIG. 2 is a side view of the line configuration shown in FIG. 1 as viewed from the B side. The weight measuring device 30 includes a transport device 32 for transporting the wood W, the transport device 32 and the transport device 32.
And a weight measuring device 34 for measuring the weight of the wood W being transported. The transport device 32 includes a pair of chain rollers C
(See FIG. 1), a sprocket S for suspending the chain roller C, a motor 36 for driving the sprocket, and a chain 38 for transmitting the driving force of the motor 36 to the sprocket side.

A moisture measuring device 50 for measuring the moisture of the wood W
A microwave irradiator 52 disposed above the transfer position of the wood W and irradiating the microwaves to the wood W, and a microwave irradiator 52 provided below the transfer position of the wood W and irradiated with the microwave from the microwave irradiator 52 A microwave receiver 54 for receiving the microwave transmitted through W. The control device 12 measures the water content (moisture content) of the wood W based on the output of the microwave receiver 54.

FIG. 3 is a view of the Young's modulus measuring device 70 for measuring the Young's modulus of the wood W shown in FIG. 2 as viewed from the arrow D side. The Young's modulus measuring device 70 includes a striking device 72 for striking the tip of the wood to be discriminated, a sound-collecting microphone 74 for catching sound when the discriminated wood W is struck by the striking device 72, and a chain roller C And a transfer device 78 including an air cylinder for transferring the lifted wood W to the stopper 76 provided on the hitting device 72 described above.

The impact device 72 includes a hammer 72A, a shaft 72B for pivotally supporting the hammer 72A, and a hammer 72A.
A hammer 72A strikes the tip of the timber W when the rod of the cylinder 72C is retracted. On the other hand, the sound collecting section of the sound collecting microphone 74 is provided with a cover 75 provided with an opening 75a on the opening side, so that directivity toward the opening side is provided.

The lifting device 80 includes a support rod 86 for supporting the wood W, and an air cylinder 82 for raising and lowering the support rod 86 via a rod 84. An elastic member 88 made of an elastic material such as rubber or resin is provided at the top of the support rod 86, that is, at the contact portion with the wood W.

FIG. 4 shows a view from the arrow E side of the printing device 90 for printing the Young's modulus on the wood W shown in FIG. The printing device 90 includes a print head 90 </ b> A disposed above the wood W conveyed on the subsequent conveyance device 22, and a wood W
And a print head 90B disposed below the print head 90B. The print head 90A and the print head 90B both use an ink jet system.

A sensor 93 for detecting the wood W is provided together with the printing device 90. The sensor 93 is provided with a plurality of infrared light emitters 93a provided above the wood W conveyed on the subsequent conveying device 22 and provided with a plurality of infrared light emitters 93a, and a light receiver provided below the wood W and provided with a plurality of light receiving elements 93b. Device 93B. That is, the light receiving element 93b of the light receiver 93B detects that the infrared light from the infrared light emitter 93a of the light emitter 93A is cut off by the arrival of the wood W.

Next, the operation of judging the Young's modulus of the discriminated wood by the wood grade discriminating apparatus will be described with reference to FIG. The wood W is placed and transported in a direction perpendicular to the transport direction of the upstream transport device 20. Front transfer device 20
When the wood W is carried into the weight measuring device 30 from the above, the weight of the wood W is measured by the weight measuring device 30. As described above, the transfer device 32 of the weight measuring device 30 uses the chain roller C
And transports the wood W onto the chain roller C.

The weight measuring device 34 also measures the weight of the wood W being transported by the transport device 32 and the transport device 32,
The measured values are transmitted to the control device 12 shown in FIG. Here, the measured value changes with time as the wood W is transported, as shown in FIG. That is, in the state where the transfer of the wood W is started to be applied not only to the transfer device 32 but also to the transfer device 20 in the state where the transfer is started from the transfer device 20 to the transfer device 32 of the weighing device, the measured value becomes low. . Then, when the wood W is completely transferred to the transfer device 32 and transferred to the center position of the transfer device 32 (time T), the measured value reaches a peak. Further, in the state where the transfer of the wood W is started not only from the transport device 32 but also from the transport device 32,
In addition, the measured value gradually decreases as the sheet is transported.

The control unit 12 controls the peak value of the measured value (see FIG. 5).
The weight of the wood W is calculated based on the time T) w1 shown in FIG.
That is, from the peak value W1, the transport device 3 that is known in advance
The weight of wood 2 is subtracted from the weight of wood 2
Find the weight of This correction value is obtained by actually flowing the wood W whose weight has been measured in advance into the wood grade discriminating device 10, measuring the weight with the weight measuring device 30, and comparing the measured value with the actual weight. Have been.

In the weight measuring device 30 of the first embodiment, since the weight is measured while transporting the wood W by the transport device 32, the weight of the wood W transported on the transport path can be measured smoothly. Here, since the weight is measured while transporting the wood W by the transport device 32, the measured value changes with the transport of the wood W. However, since the weight of the wood W is measured based on the peak value of the change, the weight is accurately measured. Can be measured.

The wood W whose weight has been measured by the weight measuring device 30 is transferred to the post-conveying device 22, and is placed and conveyed in a direction perpendicular to the conveying direction. Then, the moisture (moisture content) of the wood W is measured by the moisture measuring device 50. The moisture measuring device 50 includes a sensor 91 (see FIG. 1) similar to the sensor 93 of the printing device 90 described above with reference to FIG. Then, at the sensor 91,
When the arrival of the wood W is detected, the control device 12 irradiates the microwave from the microwave irradiator 52 to the upper surface of the wood W. Then, the microwave transmitted through the wood W is disposed below the transport position of the wood W and received by the microwave receiver 54, and the received value is sent to the control device 12 side.
The control device 12 calculates the water content (moisture content) of the wood W based on the transmitted value.

The wood W for which the moisture measurement has been completed is further conveyed by the post-conveyance device 22, and the Young's modulus is measured by the Young's modulus measurement device 70. As shown in FIG. 1, the Young's modulus measuring device 70 is provided with a sensor 92 similar to the sensor 93 of the printing device 90. Then, when the arrival of the wood W is detected by the sensor 92, the control device 12 starts measuring the Young's modulus. First, as shown in FIG. 3, the air cylinder 82 of the elevating device 80 is operated to
By 6, the wood W is lifted from the chain roller C of the subsequent conveying device 22. Next, the cylinder of the transfer device 78 is protruded as shown by a chain line in the figure, and the wood W is transferred to a position where it comes into contact with the stopper 76.

Then, the cylinder 72C of the hitting device 72 is pulled in, and the tip of the wood W is hit by the hammer 72A. Then, the striking sound is captured by the sound collecting microphone 74. The control device 12 calculates the Young's modulus from the frequency of the impact sound and the mass (weight) of the wood W measured by the weight measuring device 30.

Here, in the wood grade discriminating apparatus 10 of the first embodiment, the wood W is placed and transported in a direction perpendicular to the traveling direction of the rear transporting device 22. Then, the striking device 72 of the Young's modulus measuring device 70 is struck from the side at the lateral position of the latter conveying device 22 which does not interfere with the wood W conveyed by the latter conveying device 22, It is placed in a position where it can be done. That is, since the striking device 72 is arranged at a position where it does not interfere with the wood W, it is not necessary to raise and lower the striking device 72 every time the measurement is performed in order to avoid interference with the wood W, so that the structure can be simplified. Furthermore, since the elevating device 80 lifts the wood W from the post-conveying device 22, it is possible to capture the sound without the noise of the chain roller C of the post-conveying device 22 being superimposed, and to accurately measure the Young's modulus. Become.

In the wood grade discriminating apparatus 10 according to the first embodiment, a support rod 86 for supporting the wood W is provided with an elastic member 88 at a contact portion with the wood W. Therefore, the sound can be captured without external noise superimposed, and the Young's modulus can be accurately measured.

Further, since the impact sound is captured by the sound collecting microphone 74 having directivity, the Young's modulus can be accurately measured without superimposing external noise.

Next, the correction of the Young's modulus according to the water content by the controller 12 will be described. Although the moisture content of the wood W varies, the Young's modulus increases as the moisture content decreases. Here, the wood W has a high moisture content (20% or more) at the time of lumbering, and when used in a house or the like, the wood W gradually dries, and becomes stable in an air-dried state of about 15%. Therefore, it is desirable to display the Young's modulus in an air-dry state of 15%, which is the stable state. For this purpose, a correction coefficient Xe corresponding to the water content shown in the chart in FIG. 7 is searched, and the correction coefficient Xe is multiplied by the measured Young's modulus to obtain a 15% air-dried Young's modulus. it can.

The control device 12 of the present embodiment corrects the Young's modulus according to not only the above-mentioned water content but also a change in the sectional area of the wood W in accordance with the moisture. That is, the cross-sectional area of the wood W is
As the water content decreases, the water content decreases, and as the cross-sectional area decreases, the Young's modulus decreases. The decrease in Young's modulus due to the change in cross-sectional area based on the water content is shown as (correction value due to decrease in the second moment of area of wood) in FIG. In order to correct the cross-sectional area change of the discriminated wood according to the water content together with the above-described water content, the controller 12 adjusts the correction coefficient Xe and the cross-sectional area change according to the water content shown in the table of FIG. By retrieving the value of (Xe * Xi) multiplied by the correction coefficient Xi and multiplying the measured Young's modulus by the correction coefficient (Xe * Xi),
A 15% air-dried Young's modulus is determined.

The correction coefficient according to the change in the cross-sectional area was obtained from the following equation. First, the following equation is widely used as an equation for calculating the deflection.

[Equation 1] Deflection amount = 5wL ⁴ / (384 · E · I) where, w is a uniformly distributed load, E is a Young's modulus, L is a span, I is a second moment of area. Desired

I = (b · h ³ ) / 12 where b represents the width of the wood and h represents the height.

In the present embodiment, the correction coefficient Xi was determined from the following equation, assuming that the cross-sectional area of the wood W contracts 1% in the tangential direction of the wood tip when the water content decreases by 5%.

Xi = 1− (w−15.0) × (0.01 / 5)

The wood grade discriminating apparatus according to the first embodiment includes:
Since the measured Young's modulus is corrected by the moisture and the cross-sectional area change of the discriminated wood according to the moisture, the Young's modulus can be accurately obtained.

The control device further adjusts the corrected Young's modulus so as to conform to the standard value of wood. Here, in the present embodiment, the Young's modulus (× 10 ³ Kgf / cm ² ) is E
Less than 70, less than E90, less than E110, less than E130,
The value is any of E150. That is, when E is less than 70 (for example, E = 66), E is set to E70 and E is set to 7
When it is 0 or more and less than 90, E90 is set, and E is 90 or more and 11
When it is less than 0, it is E110, when E is 110 or more and less than 130, it is E130. When E is 130 or more (for example, E = 155), it is E150.

Subsequently, the wood grade discriminating device prints the Young's modulus divided into the above standard values on the wood W by the printing device 90 as shown in FIGS. When the control device 12 detects the arrival of the wood W conveyed on the rear conveyance device 22 by the sensor 93, it drives the print head 90A disposed above the wood W to move the print head 90A on the upper surface of the wood W as shown in FIG. As shown in A), the Young's modulus according to the above standard is printed by a numeral. At the same time, the print head 90B disposed below the wood W prints the Young's modulus on the back of the wood W as shown in FIG. 6B, which is a back view of the wood W shown in FIG. .

Although not shown, the print head 90A disposed above the wood W is provided with an automatic elevating device.
The height of the wood W is measured by a sensor (not shown).
The height of the print head 90A is automatically adjusted in accordance with the timing. In this embodiment, the height of the print head 90A is adjusted, but instead, the wood W is turned over, and the upper surface is brought to the lower side, and the upper surface is moved by the print head arranged below. It is also possible to configure so as to perform printing.

In the wood grade judging device 10 of this embodiment, the measured Young's modulus is printed by a printing device 90 on the upper surface and the lower surface of the wood W by numbers. For this reason, in post-processing,
The Young's modulus can be confirmed by cutting the end of the wood. In addition, the state where wood was accumulated at the construction site, or
The Young's modulus can be easily confirmed in a state where the wood is incorporated as a horizontal member or a pillar member. Further, since the Young's modulus is printed by numbers, anyone can determine the Young's modulus.

Next, a description will be given, with reference to FIG. 8, of a Young's modulus measuring device of a wood grade discriminating device according to a second embodiment of the present invention. The Young's modulus measuring apparatus according to the first embodiment described above with reference to FIG.
No. 5 was covered, and the directivity toward the tip of the wood W was provided. On the other hand, in the second embodiment, the hammer 72A of the striking device 72 is housed in the cover 175 made of a sound absorbing material together with the microphone 74. The cover 17
The fifth opening 175a faces the wood W side.

In the Young's modulus measuring apparatus of the second embodiment, the hammer 72A and the sound collecting section of the microphone 74 are
Since it is covered with the cover 175 made of a sound absorbing material, it is possible to capture sound without superimposed external noise, and to accurately measure the Young's modulus.

Next, a description will be given of a Young's modulus measuring device of a wood grade discriminating device according to a third embodiment of the present invention with reference to FIG. In the third embodiment, the opening 275a of the cover 275 made of a sound absorbing material is arranged at the same position as the wood side end surface of the stopper 76 so as to be in contact with the wood W. In the third embodiment, sound can be captured without external noise superimposed, and the Young's modulus can be measured accurately.

[0043]

As described above, according to the present invention, since the sound collecting device is composed of a sound collecting microphone having directivity, it is possible to capture sound without superimposing external noise and to accurately determine the Young's modulus. Can be measured.

[Brief description of the drawings]

FIG. 1 is a plan view showing a line configuration of a wood grade discriminating apparatus using a weight measuring device according to a first embodiment.

FIG. 2 is a view of the line configuration shown in FIG.

FIG. 3 is a view of the Young's modulus measuring device 70 shown in FIG.

FIG. 4 is a view as seen from an arrow E of the printing apparatus shown in FIG. 1;

FIG. 5 (A) is a graph showing a change in measured weight of wood W by a weighing device, and FIG. 5 (B) is a graph showing a relationship between a water content and a Young's modulus correction coefficient. .

FIG. 6A is a plan view of wood W on which Young's modulus is printed, and FIG. 6B is a rear view.

FIG. 7 is a table showing a relationship between a water content and a Young's modulus correction coefficient.

FIG. 8 is a side view of a Young's modulus measurement device according to a second embodiment.

FIG. 9 is a side view of a Young's modulus measuring apparatus according to a third embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 wood grade discriminating device 12 control device 20 front-stage conveying device 22 rear-stage conveying device 30 weight measuring device 32 conveying device 34 weight measuring device 36 motor 38 chain 50 moisture measuring device 52 microwave irradiator 54 microwave receiver 70 Young's modulus measurement Device 72 Hitting device 74 Sound collecting microphone 75, 175, 275 Cover 75a, 175a, 275a Opening 76 Stopper 78 Transfer device 80 Elevating device 82 Air cylinder 84 Rod 86 Support rod 88 Elastic member 90 Printing device 90A, 90B Print head C Chain roller S Sprocket W Specified wood

Claims (4)

[Claims] 1. A striking device for striking wood to be discriminated, a sound collecting device for catching sound when the striking wood is struck by the striking device, and a Young's modulus based on a frequency of the sound captured by the sound collecting device. And a Young's modulus measuring device for determining the wood grade, wherein the sound collecting device comprises a sound collecting microphone having directivity toward the discriminated wood side. 2. A striking device for striking wood to be discriminated, a sound collecting device for capturing sound when the striking wood is struck by the striking device, and a Young's modulus based on the frequency of the sound captured by the sound collecting device. And a Young's modulus measuring device for determining the wood grade, wherein the sound collecting device comprises a cover made of a sound absorbing material having an opening formed on the discriminated wood side, and a sound collecting portion protruding from the cover. The wood grade discriminating device according to claim 1, further comprising a microphone. 3. The wood grade judging device according to claim 2, wherein at least a portion of said hitting device striking said discriminated wood is accommodated in said cover. 4. The apparatus according to claim 2, wherein the opening of the cover is disposed so as to be in contact with the wood to be determined.