JPH0825161B2 - Centering method for mounting logs on a sawmill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a method for centering and attaching a log in a sawing machine that grinds a lumber from a log, and in particular, there is a difference in diameter between the source opening and the end opening. In addition, in a sawing machine used for sawing off timber from logs that have a gentle bend that can be regarded as an almost circular arc over the entire length, the log is sent with centering so that the timber of standard dimensions as thick as possible can be sawed. It relates to a method of attaching to a lumber car.

[Prior Art] This lumbering machine is provided with a feeding vehicle, a set of one or two sets of band saws provided in the vicinity of the running track of the feeding vehicle, and a device for loading and unloading logs and timber. The feeder car has a log holding device such as a push cup provided coaxially with the lumber machine spindle, for example, and holds the log by means of which a traveling track provided in parallel with the saw machine spindle. It reciprocates along and cuts the attached logs with a band saw for lumbering.

At this time, the work actually performed is centering and stepping.

Centering is, for example, when a push cup is used, determination of the relative position of the log with respect to the push cup center axis,
Specifically, it is a work that consists of determining the position of the points on both wood mouths of the log that should be matched to the tip of the pushing cup, and determining the rotation angle of the log around the center axis of the pushing cup.
This is the work of adjusting the distance between the center axis of the push cup and the cut surface of the band saw.

The logs lumbered by this lumbering machine usually have a diameter difference between the main opening and the end opening and are gentle over the entire length, but have a bend that cannot be ignored during the lumbering operation.

When cutting out one or a plurality of timbers and / or plate materials (simply referred to as timbers in this specification) from such logs, it is natural to obtain thick timbers without wasting the material as much as possible. The log is centered and attached, but until recently, these operations were entirely dependent on the experience and intuition of skilled workers.

When cutting a desired timber from a log using these sawmills, first, the main plane of the log, that is, a curve connecting the center points of the cross-sections at each position along the longitudinal direction of the log (in this specification, simply The center line of the log) and the plane of curvature of the center line of the log are attached between the pushing cups of the feeding car so that they are parallel to the cut surface of the band saw, and first parallel to the main plane. After performing double cut cutting to obtain an intermediate material having a drum-shaped cross section, this is rotated 90 degrees around the center axis of the pressing cup, and the remaining two surfaces are cut to obtain a desired square wood.

Since the shape of the log is substantially symmetrical with respect to its principal plane, the centering for the first double-cutting cutting is extremely easy and there is no particular problem. That is, the main plane is determined by detecting the bending direction of the log, the main plane is parallel to the cut surface by the band saw, and the center axis of the pushing cup of the sawmill is located on the main plane. Is.

The bend of the log or the position of the main plane can be easily determined, for example, by temporarily supporting both ends of the log with pressing cups, rotating the log around the center axis of the pressing cup, and detecting the runout at the center of the log. known.

However, the centering on the main plane, that is, the centering for cutting in the plane orthogonal to the main plane in the second step later is not easy because the log has a bend, and is solved here by the present invention. There are technical challenges to be addressed.

That is, the technical problem of the present invention is to cut a log that is gently curved in a substantially arcuate shape on the main plane by cutting it along the longitudinal direction of the log with two planes parallel to the main plane and two planes at right angles. In order to obtain, it is possible to use a cheap and simple device without using an expensive device such as a large-capacity computer or a high-class shape recognition device, and to obtain the maximum sawing efficiency in practice. To provide an efficient method.

In addition, although the centering of the log is described here by dividing it into the first and second lumbering stages, in reality, the centering of these logs is not performed separately but is performed integrally at the same time. is there.

In other words, centering is performed so that the main plane of the log is parallel to the cut surface of the band saw and the center of the pushing cup is rotated 90 degrees about the center axis so that the heart does not get out of alignment.

This conventionally known centering work is carried out by a worker who has boarded a lumbering machine's feeding vehicle, and measures the shape of the log, such as the thickness and bend of the log, with a visual or simple measuring instrument, based on many years of experience.
Using the log operating device installed in the sawmill and the push cup of the feeding car, the main plane of the log becomes vertical, and in order to obtain the most efficiently square wood from the log, This is done by adjusting the center position.

Normally, the timber cut out from the log is of standard size, but during sawing, the worker performs the centering of the log so that the timber with the largest possible cross-sectional area can be cut out from the given log. It is a thing.

The reason for this is that, when centered in such a way, the minimum value of the stock removal increases over the entire circumference of the log, the part where the stock removal becomes extremely small decreases, the failure of sawing work decreases, and the sawing efficiency decreases. Because it will be higher.

However, this known method of relying on manpower requires considerable skill and spatial recognition ability, requires a long time for centering even by a skilled worker, and often fails, and there is no guarantee that the highest lumber efficiency will always be achieved. .

In addition, this work is a heavy work with considerable danger, and it is forced to work for a long time in a place where the work environment is bad.Therefore, a successor cannot be obtained recently, and the operation of the sawmill gradually becomes obstructed. ing.

Therefore, recently, there is an increasing demand for automation of this work, but conventional automation attempts have been made by using, for example, a CCD or other shape recognition device and a large-capacity computer.
A computer is used to control the robot arm that attaches the log to the push cup or other attachment device of the feeding vehicle based on the results of the calculation for log shape recognition and centering, and to perform automatic centering. I focused on what I did.

That is, what is currently proposed is that the log is rotatably supported around a predetermined rotation center axis, the shape of the cut end of the log is imaged by a CCD or the like, and an optical or contact shape sensor is used. Measuring devices such as are installed at many points along the rotation center axis of the log at appropriate intervals, and the log is rotated around the rotation center axis to measure changes in the contour shape and bending of the log. , The center axis of the maximum square member contained in the contour is obtained, and the robot arm that holds the log is computer-controlled based on the calculation result, and the center axis of the maximum square member is set to, for example, a push cup of a feeding vehicle. It is said that the mounting is done according to the center.

This calculation is to calculate the maximum size and position of the square material inscribed in the log contour surface from the given log shape data, and the calculation is by no means simple, and the calculation amount is enormous. Therefore, a computer with a considerably large capacity is required to perform lumber at a normal speed.

Therefore, the presently proposed device of this type requires an expensive arithmetic unit which is several times as expensive as the main unit of the sawmill, and is extremely expensive. However, there is a problem that it is difficult to completely automate the sawmill process.

The reason is that the shape of the log is extremely complicated, and it is impossible to handle the complete shape data without omission.Therefore, in reality, the sample values obtained by the measuring devices installed at several places are used. Although it will be handled, if the sample value is large, the calculation will take too much time, and conversely, if the sample value is small, perfect centering calculation will be impossible and good sawmill efficiency will not be obtained. This is because, in the end, it becomes necessary for the operator to operate the robot arm while looking at the image of the computer and the like to center the log and correct the mounting posture.

In addition, these devices have a delicate structure and are not suitable for use in places where the working environment is poor, such as sawmills, and workers who used to work at sawmills for a long time in the past. It is extremely difficult to handle.

[Problems to be solved by the invention]

The present invention is intended to solve these problems, since no expensive device such as a computer or an image recognition device is used at all, or even if it is used, only a very simple, inexpensive and easy-to-handle device is sufficient. A centering method for logs that requires low equipment costs and operating costs, can completely automate the centering process in sawing work, and can achieve high sawing efficiency equivalent to using an expensive computing device. Is to provide.

[Means for solving problems]

The present invention is separated by a distance of about 70% of the length of a log of raw wood,
At the reference points A and B, which are set equidistant from both wood mouths, a log is gripped by a sandwiching device composed of a pair of V blocks, and the center of the log cross section is obtained. This was done based on the knowledge that, if it is aligned with the main axis of a sawing machine such as a cup center axis and chucked at that position, perfect centering can be automatically performed practically without any special calculation.

In other words, this leads to performing centering by regarding the cross-sectional center curve of the log as an arc.

In this way, when a log is viewed as a slender columnar body having a uniform thickness that is gently bent in an arc shape, the height H of the arc formed by the center curve of the columnar body is measured on both sides of the lumber machine spindle. The logs will be retained so that they will be distributed to each other, and the most rational centering will be realized.

That is, the gist of the present invention is that a log having a diameter difference between the front end and the end end and having a gentle bend that can be regarded as a substantially circular arc over the entire length should be made as thick as possible with a standard size timber. In the method of centering the log so that it can be ground and mounting it on the saw truck of the sawmill, detecting the bending of the log that has been loaded and connecting the center points of the cross section of the log, and the center of curvature of the center curve Hold so that the main plane of the log including and is parallel or at a right angle to the cut surface by the band saw, and keep a distance of about 70% of the total length L of the log, and equidistant from the center of both ends of the log. At the defined position, each log is gripped by a pair of V blocks that face each other, and the center points of the V blocks that face each other are set as reference points A and B, and the straight line connecting the reference points A and B is aligned with the mounting reference axis. Sending logs to a sawmill It is characterized in that attached to.

The attachment reference axis is usually the push cup center axis of the material feeding vehicle. In this case, the reference points A and B are aligned with the push cup center axis, and the logs are chucked by the push cup to perform lumber milling. .

Thus, an actual log has a taper, and an ordinary log has a shape in which a slender truncated cone having an extremely small apex angle is gently bent.

Therefore, since the diameter of an actual log increases in sequence toward the original opening, the log is seen as a cylinder with the same diameter as the end opening,
There will be a margin.

Therefore, if the center of the cross section at the reference points A and B is simply adjusted to the attachment reference axis as described above, this margin is not used at all, and it may not be possible to perform lumber with the highest efficiency.

In such a case, for example, find the diameter difference of the main part of the log,
It is possible to calculate the amount of margin in the main part of the log and correct the position of the mounting reference axis where the center of the log should be aligned.

Further, in such a case, the log is gripped by a pair of V blocks facing each other at a position different from the reference points A and B, and the cross-sectional center of the log at that position is obtained. By aligning with the mounting reference axis, it is possible to effectively use the margin and obtain a square bar with the maximum size.

[Action]

Since the present invention is configured as described above, according to the present invention, the centering and mounting of logs can be automatically performed without the need for a skilled worker, and the occurrence rate of defects due to the failure of lumber can be reduced. The log is significantly reduced, which enables extremely efficient and economical sawmilling, and is a fully automatic log that can be operated unattended for a long time without using an expensive large-capacity computer or image recognition device. It is possible to provide a centering device.

[Best Mode for Carrying Out the Invention]

Hereinafter, the method of the present invention will be specifically described with reference to the drawings.

FIG. 1 is an explanatory view of the principle of the centering attachment method according to the present invention, and FIG. 2 is an explanatory view showing an example of a more preferable centering method when there is a difference in diameter between the root and end openings of logs. FIG. 4 is an explanatory view showing the relationship between the cross-sectional shape of the log and the obtained timber at the midpoints of both ends of the log and the center curve, and FIG. 4 shows the device that can be used to carry out the centering attachment method according to the present invention. It is a side view which shows an outline.

In addition, although the actual log has a substantially circular cross section, in order to simplify the description in these drawings, the log is shown as a planar one in FIGS. 1 and 2. That is, what is shown in the figure is a fan-shaped plate body in which a log is thinly sliced in the main plane portion, and a rectangular plate is cut out from this. Also, in the figure, the bending of the logs and the difference in diameter are emphasized.

Further, the log 1 generally has bending and twisting, but the log suitable for lumber has less twisting and the bending is limited to within a certain allowable limit, so the twisting is ignored here, and the bending is an arc shape. The curvature will be described as being small and constant over the entire length of the log.

Further, although the end surface of the actual log has an irregular shape, it is assumed here that the irregular portion and unnecessary portions are excluded.

 Hereinafter, description will be sequentially given from FIG.

FIG. 1 is a diagram showing a state in which a log is thinly cut along a main plane of the log 1, that is, a plane including a center curve connecting the cross-sectional center points of the log and the center of curvature of the center curve. The lumbering work will be described as cutting out a rectangular plate.

In FIG. 1, 1 is a log, 1a is a center curve thereof, 1b indicated by a broken line is a square timber cut out from the log 1, X ₀ is a main axis of a sawmill, that is, a central axis of a pushing cup. .

Here, the log 1 will be described as being attached between push cups of a material feeding vehicle, but the present invention can be applied to any log attachment device other than push cups.

It should be noted that FIG. 1 is for simply explaining the basic principle of the present invention, and here it is assumed that the thickness D _{S of the} log is uniform from the front end to the end end.

It is assumed that the log 1 is uniformly curved gently in an arc shape, and its center curve 1a is an arc SACBT having a radius R (hereinafter simply referred to as arc ST).

Also, S and T are the centers on both end faces of the log on the trailing edge side and the original mouth side, respectively, and C is a point on the arc ST equidistant from both ends of the log, that is, the midpoint of the arc ST. To do.

When the center of the string ST is D, the height of the arc ST is H
Is the amount of bending of the log.

In this case, rational centering is realized by mounting so that the bending amount H is distributed to the upper and lower sides of the push cup center axis X _{0 of the} material feeding vehicle.

That is, a line passing through the midpoint E of the CD, parallel to the string ST, and an arc ST
Assuming that the intersections with and are A and B, the straight line AEB should be pressed to coincide with the cup center axis X ₀ .

At this time, the length L _AB of the string AB is calculated as follows.

However, the length of the log, that is, the length of the string ST is L, the height of the string AB is h, the central angle of the string ST is θ, and the central angle of the string AB is η.
And

In that case, regarding the arc ST, Now, assuming that the log has a small bend, 2R >> L, so And meanwhile And, and Therefore, Becomes

Similarly, for arc AB, Therefore, Also, in order to perform the best centering, Since, That is, the distance L _AB between the reference points A and B should be about 70% of the total length L of the log 1.

Since it is desirable to provide the reference points A and B symmetrically with respect to the center plane CD, the reference points A and B are about 15% of the total length L of the log 1 from the end opening and the base opening, respectively.

Hold the log at the position corresponding to these reference points A and B,
Press the center of the log section at those positions and press the cup center axis.
If it matches X ₀ , it means that the optimum positioning is performed.

In determining the reference points A and B, it is needless to say that the length L of the log may be measured one by one, but normally the length L of the log is set to be substantially constant for each lot. Therefore, even if the average value or the nominal size is adopted, there is no practical problem.

Thus, in the above description, the diameter of the log has been described as being constant, but since the actual log tapers from the front end to the end end, the maximum lumber efficiency cannot always be obtained by the above. Sometimes.

That is, as shown in FIG. 2, the log 1 is not a simple columnar shape as shown in FIG. 1 described above, but has an extremely small apex angle and is a slender truncated cone shape bent in an arc shape. Has become.

As can be seen from the figure, when the log is considered to be a slightly bent cylinder, the portion with the most margin is the side of the center of curvature of the log (hereinafter referred to as the inner side) and the side opposite to the center of curvature of the ends (hereinafter, Outside).

Therefore, considering the taper of the log, when centering by the above method, there is actually a margin at the center and the front mouth side of the log, and if this is effectively used, the lumber efficiency will be further improved. Turns out to get.

In order to effectively use such a margin, reference points A and B
Instead of directly aligning the cross-sectional center of the log with the main axis of the sawing machine, it is also possible to make it coincide with the mounting reference axis that is provided in parallel with it at a minute distance, or the mounting reference axis that is determined by inclining it at a minute angle. Recommended.

The distance or angle between these mounting reference axes and the lumber machine spindle is
As described below, depending on the shape of the log and the capability of the arithmetic and control unit to be used, it is determined so that a square bar as thick as possible can be obtained.

 The setting method of the mounting reference axis will be described below.

FIG. 3 is a view showing a cross section perpendicular to the central axis of the log. The cross section of the log's end opening, center, and main opening shown in FIGS. 1 and 2 and the cross section of a lumber cut out from the log. It is shown.

In the figure, C _S is a circle showing the outline of the log at the end opening, C _C0 and C _M0 are circles showing the outline at the center and the original opening of the curved cylindrical log shown in FIG. 1, C _C and C _M are the circles that show the contours at the center and the mouth of the logs with different curvatures and diameters shown in Fig. 2, and G _M is a straight cylindrical log with no curvature and a diameter of D _S. The square member having the maximum facing distance obtained from (the facing dimension is W), G _S is the bending amount H shown in FIG. 1, and the square member obtained from a log having a constant diameter (the facing dimension is W ′ It is).

Thus, from the diameter D _S of these logs and the bending amount H,
The face-to-face dimension W of the square member G _{M and} the face-to-face dimension W'of the square member G _S are obtained, and the center position can be corrected based on this.

That is, if a log with a diameter difference between the end opening and the base opening and a bend is calculated, the margins Δ _S and Δ that occur at the inner end and the center of the log can be calculated. Is to be corrected.

Therefore, the bending amount H is determined by determining the main plane of the log,
It is inevitably measured, and D _S , D _M and D _A , D _B are logs with V at the end opening, main opening and reference points A and B, respectively.
It will be known immediately if grasped by a block.

Therefore, Δ is calculated from those values, and the magnitude of H is compared with H. However, if H <Δ, the contour line on the curvature center side of the log in the main plane of the log is the second It does not become a concave arcuate curve as shown in the figure, on the contrary, because it will be projected toward the center of curvature, there is no effect of bending, it is not originally according to the method of the present invention, It is only necessary to align the center of the cross section of both the wood openings with the reference axis so that a timber of a size inscribed in the cross section of both wood openings, especially the cross section of the end wood, can be taken, so here it is assumed that H> Δ. To do.

Therefore, when considering the taper of the log, if the core position of the log is corrected in consideration of this margin Δ, a considerably thick square bar can be obtained as compared with the above case.

Even in the method of the present invention, if the equipment cost of the apparatus is to some extent high, the diameter and bending amount of the log front end and the end or the reference points A and B are measured. However, it is desirable to use a device that calculates the margins at the center of the trailing edge and the log and corrects the center position of the log so that the margin of the smaller one of them is eliminated.

Thus, in order to correct the center position of the log, a method of providing the mounting reference axis of the log in parallel with a small distance from the center axis of the pressing cup and a method of providing it with a slight angle inclination are conceivable. In any case, since a special shape recognition device is not required and a complicated calculation is unnecessary, a computer with a very small capacity is sufficient.

The shape of the log is not such that the slender truncated cone shape is gently bent in an arc shape as assumed here, the cross section is also non-circular, the curvature is not constant, there is also twisting, The diameter also does not change uniformly in the longitudinal direction, and furthermore, there are bumps, knots, cavities, ax scratches, etc. on the surface, but according to the method of the present invention, it is practically the same as that using a large capacity computer. It has been demonstrated that a degree of sawing efficiency can be obtained.

Next, an apparatus for carrying out the method of the present invention will be described with reference to FIG.

In the figure, 1 is the above-mentioned log, 2 is a centering device, 3 is a tact conveyor for carrying in logs, 4 is a log mounting attitude control device,
Reference numeral 5 is a log receiving guide, and 6 is a log checker to be carried in.

The tact conveyor 3 includes a belt 31, a drive pulley 32, and a drive device (not shown), and carries the log 1 into the single-addressed device.

The receiving guides 5 are respectively provided on the front side and the rear side of the logs carried by the tact conveyor 3, and receive the logs carried by the tact conveyor 3.

The centering device 2 measures the first position indicated by a thin line in the drawing, that is, the shape of the log carried into the receiving device by a turning drive device (not shown), and the position to be grasped is indicated by a thick line. 180 ° between the second position, i.e. the mounting position for holding the logs between the push cups on the feeder car (not shown).
It can be turned once.

In the figure, 20 is the central axis of rotation, 21 is a swing arm, 22 and 23 are V-shaped clamps that pair and hold the log 1, 24 is the distance between the clamps 22 and 23, and the log diameter is measured. Positioner to detect, 25 and 26 are clamp drive arm, 27
Is a turnbuckle for opening and closing the clamp, 28 is a motor, and 29 is a gear.

Further, the mounting attitude control device 4 detects the bending of the carried-in log and positions the main plane of the log in the vertical direction.
Is a device for correctly grasping the arm 41, which is rotatably supported by a support shaft 40, an actuator 42 for rotating the arm 41, a pair of rotary rollers 43 corresponding to the original and end openings of the log, respectively. 44, a measuring arm 45 provided corresponding to the approximate center of the log, a pivot 46 rotatably supporting the measuring arm 45, a positioner 47, a stopper 48 and a spring 49.

The mounting posture control device 4 swings between the retracted position indicated by the thick line and the measurement position indicated by the thin dashed-dotted line by the expansion and contraction of the actuator 42.

When the log 1 is loaded into the receiving device 5, the actuator
42 is extended, and the mounting posture control device 4 occupies the measurement position 4 indicated by a thin chain line.

The log 1 is lifted up to about the center of the clamps 22 and 23 by the rotating rollers 43 and 44 provided at the original opening and the ending opening, respectively, and the rotation of these rollers causes the log 1 to rotate around its longitudinal central axis. It can be rotated in the direction of.

The measuring arm 45 is pushed down by the weight of the log 1 against the elastic force of the spring 49 and acts on the positioner 47, whereby the bending of the log 1 is detected.

The rotation of the log is stopped at the position where the maximum bending is directly below the log 1, the motor 28 is rotated, the clamps 22 and 23 are closed, and the log 1 is gripped.

As described above, the clamps 22 and 23 are respectively provided on the root opening side and the tail opening side of the log. Due to the action of the V-shaped clamp, the center of the log cross section at the grip portion is the clamp. Will be aligned with the center of.

In this state, the attachment attitude control device 4 is returned to its retracted position, the centering device 2 is turned 180 degrees about the turning center axis 20, and the log 1 is conveyed between the push cups of the material feeding vehicle.

By doing this, as described above, the optimum centering can be performed, so that the pushing cup is moved to set the log 1 correctly in the feeding vehicle, and then the same step as in the known sawmill is started. Then, the feeding car is reciprocated toward the rotating band saw to obtain a predetermined square bar.

As described above, according to the method of the present invention, it is possible to perform lumber with high efficiency and fully automatic unmanned operation without using a large computer or an image processing device.

The configuration of the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be applied not only to a square bar, but also to a plate or a square bar.

[Brief description of drawings]

FIG. 1 is an explanatory view of the principle of the centering mounting method according to the present invention, and FIG.
The figure is an explanatory view showing an example of a more preferable centering method when there is a difference in the diameter of the root and the end of the log, and Fig. 3 is the cross-sectional shape of the log at both ends of the log and the midpoint of the center curve. And FIG. 4 is a side view showing an outline of an apparatus that can be used for carrying out the centering attachment method according to the present invention. 1 …… Log 2 …… Centering device 3 …… Tact conveyor 4 …… Mounting posture control device 5 …… Log receiving guide

Claims (2)

[Claims] 1. A log having a difference in diameter between the base end and the end end and having a gentle bend that can be regarded as a substantially circular arc over the entire length is centered so that a log having a standard size as thick as possible can be ground. In the method of mounting the log in the sawmill of a sawmill, the main curve of the log including the center curve formed by connecting the center points of the cross sections of the log by detecting the bend of the carried log and the center of curvature of the center curve. Hold the log so that the plane is parallel or at a right angle to the plane cut by the band saw, and separate the log by a distance of approximately 70% of the total length L of the log and at an equal distance from the center of both ends of the log. Each of them is gripped by a pair of V blocks facing each other, and the center points of the V blocks facing each other are set as reference points A and B. A straight line connecting the reference points A and B is aligned with the mounting reference axis to feed a log. Made by mounting on How to install the centering of logs on a lumber machine. 2. The method for centering and attaching a log in a sawmill according to claim 1, wherein the attachment reference axis is a push cup center axis of a material feeding vehicle.