JPH0720027A - Method and instrument for measuring young's modulus of grading machine - Google Patents

Abstract

PURPOSE:To provide a Young's modulus measuring method by which the Young' s modulus of wood can be measured inexpensively with a simple structure and the variation of the Young's modulus can be found. CONSTITUTION:A first displacement is given to wood 10 to be measured and, at the same time, a first reaction which is variably generated in response to the displacement is measured while the wood 10 is passed through a first station 56 provided on a straight pass line PL so that the wood 10 can be displaced constantly, and then, second displacement larger than the first displacement is given to the wood 10 and, at the same time, a second reaction which is variably generated in response to the displacement is measured while the wood 10 is passed through a second station 58 provided on the downstream side of the line PL so that the wood 10 can be displaced constantly. Then the first and second reactions variably measured at the first and second stations 56 and 58 are compared with each other synchronously to the positions of the wood 10 and the Young's modulus of the wood 10 in its moving direction is continuously calculated from the difference between the two reactions and the constant displacement difference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Young's modulus measuring method in a grading machine for selecting wood grades, and an apparatus for suitably carrying out the method.

[0002]

2. Description of the Related Art Wood is widely used for structural members for homes, fittings, furniture, crafts, etc. due to its excellent properties. However, since wood is a natural material, there are variations in its strength, and when it is used as an industrial material or a structural member for a house, the part where strength is required,
It is important to properly use the parts that are not necessary. That is, when wood is used in a place where strength is particularly required, such as an industrial material or a structural member for a house, it is necessary to evaluate in advance the strength suitable for the application and its distribution.

From this point of view, a wood grade sorter capable of mechanically measuring the strength of wood to make a grade classification relating to the strength of the wood has already been put into practical use. This wood grade sorter is roughly classified into a guaranteed load tester (proof loading machine) and a grade sorter (grading machine). The former guaranteed load tester is a quality measuring machine that mechanically applies the required stress (estimated to be incurred during actual use) to the wood to be tested to ensure safety in the operating environment. Is. Therefore, the load applied is relatively large, and stresses of about the short-term allowable stress or more are sometimes applied.
Therefore, a material having a low strength or a defect such as a crack or a knot is immediately broken at that portion, and a quality judgment that the material is rejected is made.

The latter grade selection tester is basically a non-destructive tester, and is a target technology to which the present invention is applied. This is a technique for inspecting and selecting grades related to wood strength, and as a basic method of grade selection,
The mainstream technique is to estimate the strength by measuring the Young's modulus of the wood used for the test. That is, a required load is applied to wood, and the Young's modulus is calculated from a known calculation formula based on the displacement (deflection) generated by the load and the load. The applied load may be much smaller than that of the above-mentioned guaranteed load tester, and it is sufficient to apply a load that causes a long-term allowable stress at the maximum. This grade selection tester is also generally referred to as a "grading machine", and hence this term will be used hereinafter.

[0005]

As described above, the conventional grading machine applies an external load to a portion of the wood to be measured, and the displacement and the previous load when the wood bends due to this load. From this, the Young's modulus is calculated. Most conventional grading machines hold a piece of wood to be measured in a stationary state and apply an external load to a portion where the strength of the wood is desired to be measured one by one, and are so-called batch type machines. The measurement efficiency was extremely poor. Therefore, a grading machine has been proposed that enables the Young's modulus of the wood to be measured while continuously feeding the wood. For example, load detecting means such as a load cell is arranged on the front surface side and the back surface side of the wood across the traveling path of the wood, and the fluctuation of the reaction force on the front surface and the back surface generated by a constant displacement is continuously detected. Then, the Young's modulus is calculated from the average value of the obtained values. However, this has the drawback that the structure is complicated and the manufacturing cost is extremely high.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned drawbacks inherent in the grading machine according to the prior art, and has a simple structure and a low manufacturing cost. Moreover, it is an object of the present invention to provide a Young's modulus measuring method and apparatus capable of continuously knowing the variation of Young's modulus of wood and the distribution of the Young's modulus.

[0007]

In order to solve the above-mentioned problems and preferably achieve the intended purpose, the Young's modulus measuring method according to the present invention is based on the displacement applied to the wood and the reaction force generated by the Young's modulus. In the grading machine for measuring the strength of the wood, the wood to be measured passes through the first station provided along a straight path line in a state where the displacement is constant. While applying the first displacement while measuring the first reaction force which fluctuates with this, the second station provided downstream of the first station along the straight path line A second displacement larger than the first displacement is applied while allowing the wood to pass through in a state where the displacement is a constant amount, and a second reaction force that fluctuates correspondingly is measured, and the first displacement is measured. Ste The first reaction force that is variably measured by the measurement and the second reaction force that is also variably measured by the second station are compared and compared in the state where the measurement material is positionally synchronized. The Young's modulus in the moving direction of the wood is continuously calculated by the difference between the two reaction forces and the constant displacement difference.

Further, in order to overcome the above-mentioned problems and achieve the intended purpose, a Young's modulus measuring device according to another invention of the present application measures Young's modulus from displacement applied to wood and reaction force generated by the displacement. In the grading machine for evaluating the strength of the wood, the first station and the second station are arranged from the upstream side to the downstream side along a straight path line through which the wood to be measured passes. The first station and the second station are respectively arranged at required intervals along the pass line, and the upper surface of the first drive roller and the second drive roller are aligned with the pass line, and the path. A first clamp roller that faces the first drive roller and the second drive roller with the line interposed therebetween and is rotatable while maintaining a gap according to the plate thickness of the wood. And a second clamp roller, and a displacement imparting roller located between the first drive roller and the second drive roller and biased to the clamp roller side with respect to the pass line, and a load detection means connected to the displacement imparting roller. And the displacement amount of the displacement imparting roller provided in the second station is set to be larger than the displacement amount of the displacement imparting roller provided in the first station.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A Young's modulus measuring method for a grading machine and an apparatus therefor according to the present invention will be described below with reference to the accompanying drawings, with reference to a preferred embodiment. FIG. 1 shows a grading machine according to an embodiment in a side view, and a symbol PL in the drawing indicates a straight pass line through which the wood 10 is fed horizontally. This pass line P
Below the L, a machine base FB composed of a frame structure is arranged in parallel with the L. The machine base FB includes a plurality of vertically-standing upright columns 34, a horizontal beam 21 horizontally extending over the tops of the upright columns 34, and an intermediate beam 46 vertically extending between the upright columns 34. It consists of As is clear from FIG. 2, the machine base FB is a box-shaped structure as a whole. The machine base FB that horizontally extends as the box-shaped structure is roughly divided into a first station 56 located on the right side of the middle portion in FIG. 1 and a second station 58 located on the left side. . Since the members forming the first station 56 and the second station 58 are basically the same, only the structure of the first station 56 on the right side will be described in the present specification.
Regarding the second station 58, the first station 56
Only the differences from and will be touched upon.

In the first station 56 shown in FIG. 1, a pair of first drive rollers 12 are provided upstream of the horizontal beam 21 constituting the upper part of the machine base FB, and also at a downstream side thereof separated from the horizontal drive 21 by a required distance. Second drive roller 1 paired with
3 are rotatably provided respectively. That is, the first drive roller 12 on the upstream side is composed of a pair of rollers rotatably supported by a bearing 19 fixed to the upper part of the horizontal beam 21, and as shown in FIG. It is rotationally driven in a fixed direction by the provided material feeding motor 50. The power transmission is performed by the sprocket 54 of the motor 50, the sprocket 54 provided on the rotating shaft of the first drive roller 12, and the chain 52 that is bridged over these sprocket groups. The second drive roller 13 on the downstream side is also composed of a pair of rollers rotatably supported by a bearing 19 fixed to the upper part of the horizontal beam 21, and is also driven to rotate in a fixed direction by the material feeding motor 50. It has become. The upper surfaces of the first driving roller 12 and the second driving roller 13 are positioned so as to be aligned with the horizontally extending pass line PL.

In the first station 56, a first clamp that is rotatable at an upper position facing the first drive roller 12 with the pass line PL interposed therebetween and that is rotatable at an interval corresponding to the plate thickness of the wood 10 is held. Rollers 14 are correspondingly arranged. Similarly, the second clamp roller 15 which is rotatable at an upper position facing the second drive roller 13 with the pass line PL interposed therebetween while keeping an interval corresponding to the plate thickness of the wooden piece 10 is possible.
Are arranged correspondingly. In the illustrated example, of the pair of the first drive roller 12 and the pair of the second drive roller 13,
The drive roller located on the left side and the clamp roller face each other. This first clamp roller 14
Since the second clamp roller 15 and the second clamp roller 15 have basically the same configuration, only the specific configuration of the first clamp roller 14 will be described. The first clamp roller 14 is the bearing 1
6 is attached downward to the lower surface of a long horizontal arm 18, and one end of this horizontal arm 18 is pivotally attached to a fixed portion (not shown) of the grading machine via a support shaft 20 so as to be swingable. Has been done. The other end of the arm 18 is
It is pivotally attached via a pin 24 to (the piston rod 25 of) the air cylinder 22 attached downward to the upper horizontal beam 23 of the machine base FB.

The first clamp roller 14 can be raised and lowered by operating a means (not shown) so that a gap corresponding to the plate thickness of the wood 10 can be set between the first clamp roller 14 and the first drive roller 12. It has become. Then, after the interval is set according to the plate thickness of the wood 10, the first clamp roller 14 is pressed by the air cylinder 22 with a sufficiently large force, so that the first drive roller 12 will be described later.
And the wood 10 located between the first clamp roller 14
Will be passed while being pressed firmly by both rollers 12,14. The air cylinder 22 is biased by a constant air pressure,
When the plate thickness of 0 fluctuates significantly, the piston rod 25 of the air cylinder 22 is retracted, and the first clamp roller 14 can be retracted upward. Also the first
The clamp roller 14 and the second clamp roller 15 are
It may be free rotation that is not positively driven by other members, or may be positively driven by a motor to move in the same direction as the first driving roller 12 and the second driving roller 13 which face each other (the wood 10 in FIG. 1 is fed to the left side). Be supplied) to be rotated at the same speed. Further in the illustrated embodiment,
The inter-axis dimension of the first clamp roller 14 and the second clamp roller 15 is set to 1200 mm as an example.

In the first station 56, a displacement applying roller 26 is rotatably provided approximately in the middle of the first driving roller 12 and the second driving roller 13, and the displacement applying roller 26 is represented by a load cell. It is connected to the load detection means 30. The displacement imparting roller 26 is
Beyond the pass line PL, the first clamp roller 14,
The second clamp roller 15 side is biased by a required adjustment amount. That is, the upright columns 34 that form the machine base FB.
A linear rail 36 is vertically disposed on the linear rail 36, and a key-shaped bracket 32 is disposed on the linear rail 36 via a linear slider 38 so as to be vertically movable.
The displacement imparting roller 26 is rotatably supported on the upper surface of the horizontal portion of the bracket 32 via a bearing 28.
The load detecting means 30 is closely fixed to the lower surface side of the horizontal portion. A support 44 is mounted upright on the intermediate beam 46 which is located below the load detecting means 30 and which is horizontally arranged on the machine base FB. And the support 4
The upper end of the adjusting screw 48 provided upright on the No. 4 is in contact with the lower surface of the load detecting means 30. And the adjusting screw 48
The bracket 32 supporting the displacement imparting roller 26 moves up and down along the linear rail 36 within a prescribed range by rotating the. This amount of elevation can be read by the dial gauge 40 shown. In the present embodiment, basically, the upper surface of the displacement imparting roller 26 is adjusted by the adjusting screw 48 so as to be displaced above the pass line PL by a required distance. The lower limit of the bracket 32 is set by a stopper 42 shown in the figure.

The first drive roller 12, the second drive roller 13, the first clamp roller 1 in the first station 56.
4, second clamp roller 15 and displacement imparting roller 26
The arrangement configuration of No. 2 is as described above, and therefore the arrangement configuration of the roller group in the second station 58 provided on the downstream side has basically the same configuration. However,
The displacement imparting roller 26 in the second station 58 is
The deviation amount with respect to the pass line PL is set to be larger than that of the displacement imparting roller 26 in the first station 56. For example, if the displacement amount of the displacement imparting roller 26 at the first station 56 is δ ₁ (example: 2 mm),
The deviation amount of the displacement imparting roller 26 at the station 58 is δ
₂ (example: 8 mm), and the relationship of δ ₁ <δ ₂ is established. Further, in each station 56, 58, a sensor 60 is provided in the middle of the pair of second drive rollers 13 located on the downstream side. It sends the detection signal to. As an example, the first station 56
Then, the wood 10 whose supply has been started is first sandwiched between the first drive roller 12 and the first clamp roller 14 on the upstream side. As the supply further proceeds, the wood 10 comes to be sandwiched between the second drive roller 13 and the second clamp roller 15 on the downstream side. In this way, when the wood 10 reaches a state of being stretched between the upstream rollers 12 and 14 and the downstream rollers 13 and 15, the tip of the wood 10 is detected by the sensor 60.

Next, an actual method for measuring the required Young's modulus of the wood 10 using the grading machine having this structure will be described. As shown in the schematic view of FIG. 3, the wood 10 to be measured is fed horizontally, and the first drive roller 12 and the first drive roller 12 on the upstream side of the first station 56 are fed.
Between the clamp rollers 14 and the downstream second drive roller 1
3 and the space between the second clamp roller 15. At this time, the timber 10 has the first clamp roller 14 and the second drive roller 13 located above the first drive roller 12.
The bearing 16 located above the upper part of the upper part of FIG.
Further, the displacement imparting roller 26 located between the first drive roller 12 and the second drive roller 13 has its roller upper surface biased upward by a required distance from the pass line PL. Therefore, while the wood 10 is being fed across the first drive roller 12 and the second drive roller 13, the displacement imparting roller 26 imparts a first displacement to the surface of the wood 10. It will be. Moreover, the wood 10 is
Since the first clamp roller 14 and the second clamp roller 15 are pressed so that they cannot be displaced, the first reaction force corresponding to the first displacement given by the displacement imparting roller 26 is the load detecting means 30. Detected by. The first reaction force variably occurs as the wood 10 is fed.

As described above, the displacement giving roller 26 in the second station 58 is set to have a larger deviation amount than the displacement giving roller 26 in the first station 56 so as to project above the pass line PL. Therefore, the wood 10 enters the second station 58 via the first station 56, and is located between the first drive roller 12 and the first clamp roller 14 on the upstream side and the second drive roller 13 and the second drive roller 13 on the downstream side. When it is laid across the clamp rollers 15 so that it can travel and cannot be displaced, the displacement imparting rollers 2
6 is a second reaction force larger than the first reaction force, and the wood 10
Will be caused to. That is, when the wood 10 is fed across the first drive roller 12 and the second drive roller 13, since the wood 10 cannot be displaced, the load applied to the second station 58 Detection means 3
At 0, the second reaction force that changes in accordance with the feeding of the wooden piece 10 in correspondence with the second displacement is detected. This second reaction force is
Of course, it is larger than the first reaction force generated at the first station 56.

As described above, the first reaction force is detected by the load detecting means 30 provided in the first station 56, and the second reaction force is detected by the load detecting means 30 provided in the second station 58.
The reaction force of is detected. Therefore, the first reaction force and the second reaction force will be compared, but when the first reaction force occurs,
Since the second reaction force precedes the time when it occurs, it is necessary to positionally synchronize the measurement material.
For this purpose, as described above, the tip of the wood 10 is attached to the sensor 6 provided on the second drive roller 13 of the first station 56.
Data regarding the first reaction force detected by the load detecting means 30 is taken into the control circuit from the time point when it is detected as 0. Further, the tip of the wood 10 is the second station 58.
The data relating to the second reaction force detected by the load detecting means 30 is loaded into the control circuit from the time when the sensor 60 provided on the second drive roller 13 detects the data. Then, the first reaction force and the second reaction force are positionally synchronized with each other in the control material in the control circuit to calculate the difference between the two reaction forces. Then, the Young's modulus in the moving direction of the wood is continuously calculated and the Young's modulus distribution is determined based on the obtained difference between the reaction forces and the constant displacement difference amount with respect to the wood 10. The calculation of the Young's modulus uses a known calculation formula as described above, and thus this will not be described. After that, it is more preferable if the Young's modulus distribution is color-coded and printed on the surface of the wood 10 by, for example, color-coded stamp rollers so that the user can visually confirm the distribution.
In addition, between the first station 56 and the second station 58, the displacement imparting roller 26 is provided at the first station 56.
In order to temporarily release the stress applied to the wood 10 by the above, it is preferable to provide a constant stress release zone.

[0018]

As described above, according to the Young's modulus measuring method for a grading machine and the apparatus therefor of the present invention, the Young's modulus of the wood can be real-timed by continuously feeding the wood and making one pass. The Young's modulus distribution can be determined along with the calculation. Moreover, there are excellent advantages such as a simple device configuration and a low manufacturing cost.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic configuration of an apparatus for carrying out a Young's modulus measuring method according to the present invention.

FIG. 2 is a front view of the device shown in FIG.

FIG. 3 is an explanatory diagram showing an outline of a method according to the present invention.

[Explanation of symbols]

 10 Wood 12 First Drive Roller 13 Second Drive Roller 14 First Clamp Roller 15 Second Clamp Roller 26 Displacement Roller 30 Load Detection Means (Load Cell) 56 First Station 58 Second Station PL Pass Line

Claims (3)

[Claims] 1. A grading machine in which Young's modulus is measured from a displacement applied to wood and a reaction force generated from the displacement to evaluate the strength of the wood. The grading machine is provided along a straight pass line (PL). First station
The first displacement is given to (56) while passing the wood (10) to be measured in a state where the displacement is constant, and the first reaction force that fluctuates with this is measured. , Along the straight path line (PL) at the first station (5
At the second station (58) provided on the downstream side of 6), the wood (1
0) is passed with a constant amount of displacement, a second displacement larger than the first displacement is applied, and a second reaction force that fluctuates with the second displacement is measured. The first reaction force variably measured at the 1 station (56) and the second reaction force variably measured at the second station (58) were positionally synchronized with each other. Compared in the state, by the difference of the two reaction forces and the constant displacement difference,
A Young's modulus measuring method for a grading machine, characterized in that Young's modulus in the moving direction of the wood (10) is continuously calculated. 2. A wood grade (10) to be measured is passed through in a grading machine in which Young's modulus is measured from the displacement given to the wood and the reaction force generated thereby to evaluate the strength of the wood. Straight path line
Along the (PL), the first station (5
6) and the second station (58) are arranged, and the first station (56) and the second station (5
Each of 8) is a first drive roller (12) and a second drive roller (13) which are arranged along the pass line (PL) at required intervals and whose upper surfaces are aligned with the pass line (PL). ) And the first drive roller (12) and the second drive roller (13) respectively with the pass line (PL) in between, and can rotate while maintaining a gap corresponding to the plate thickness of the wood (10). Na first clamp roller
(14) and the second clamp roller (15), and the first drive roller (12) and the second drive roller (13) are located intermediately, and the clamp roller (14, The displacement imparting roller (26) biased to the side of (15) and the load detecting means (30) connected thereto, and the displacement amount of the displacement imparting roller (26) provided in the first station (56) A Young's modulus measuring device for a grading machine, characterized in that the displacement imparting roller (26) provided in the second station (58) is set to have a large deviation amount. 3. A first station (56) and a second station (58) for releasing the stress applied to the wood (10) by the displacement applying roller (26) at the first station (56).
The Young's modulus measuring device of the grading machine according to claim 2, wherein a stress release zone is provided between the stress relief zone and the stress relief zone.