JPH0438561B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves cutting a veneer by moving a planer stand while holding and rotating the raw wood with a spindle rotation mechanism, and conveying it by a conveyor installed to be able to control the speed uniformly. This relates to a device that detects the amount of vertical displacement of a veneer during cutting and automatically follows the same speed.

Usually, the veneer lace 1 is composed of a spindle rotation mechanism 3 that grips and rotates the raw wood 2, and a planer stand 6 having a blade 4 and a cutting edge 5 that move forward and backward with respect to the spindle rotation mechanism 3. A conveyor 8 is installed to convey the cut veneer 7 to the next stage of the veneer winding process.

The spindle rotation mechanism 3 includes a veneer race 1
It is rotated via a variable speed motor 10 that rotates at a continuously variable speed by a lever 9 operated by a driver, and the rotation speed is detected by a detection generator 11 connected to the variable speed motor 10 during normal operation. ing.

On the other hand, a variable resistor 12 is attached to the planer stand 6, and detects the amount by which the planer stand 6 moves in accordance with the decrease in the diameter of the log 2, and a calculation is made by connecting this variable resistor 12 and the detection generator 11. The circuit 13 constantly calculates the cutting speed of the veneer 7 and transfers it to the conveyor 8.
The variable speed motor 14 that drives the veneer 7 is instructed to
The cutting speed of the conveyor 8 and the circumferential speed of the conveyor 8 are controlled to be uniform.

However, the veneer 7 cut from the raw wood 2 tends to elongate immediately after cutting due to changes in its material.
In addition, during cutting, when controlling the rotation speed of the spindle rotation mechanism 3 to either high or low due to changes in the thickness of the veneer 7, etc., a high-speed response error occurs with respect to uniform speed control of the conveyor 8, which causes further cutting. When conveying the veneer 7, uniform speed synchronization is hindered by mechanical errors caused by slips with the conveyor 8, etc.

When this uniform speed error occurs, the veneer 7 that is continuously cut will be displaced either up or down on the back of the planer stand 6 or on the conveyor 8. That is, when the circumferential speed of the conveyor 8 becomes faster than the cutting speed, the veneer 7 becomes in a tensile state where it is displaced upward, and in an excessively tensile state, the veneer 7 tears in the direction of its fibers, and vice versa. When the veneer 7 slows down, the veneer 7 is in a deflected state where it is displaced downward, and in an excessively deflected state, it is wound up while being folded over each other, and when it is unwound, the veneer 7 is torn in the direction of its fibers. There is a risk.

For this reason, in order to correct the above-mentioned speed uniformity error, various methods have been adopted to detect the vertical displacement of the veneer 7 to be cut and to follow the circumferential speed of the conveyor 8. Specifically, there is a mechanical method in which a swingable lever is hung vertically above the veneer 7 that is being transported, and the amount of swing of the lever is detected by a limit switch, or a reflective phototube is suspended and the veneer 7 is moved to the veneer 7. There are methods to detect the moisture content of the veneer 7 by detecting an increase or decrease in the amount of reflection, and a method to detect the moisture content of the veneer 7 using capacitance by placing a hollow wire. After being converted into a signal, it is transmitted to the variable speed motor 14 of the conveyor 8, and the circumferential speed is controlled accordingly.

However, the material of the veneer 7 to be cut is fragile, and the color of the veneer 7 may vary due to the process of cutting a single log 2 from its surface layer to the core layer, and due to differences in the wood species of the log 2. Since the mechanical and moisture content changes are wide-ranging, the conventional methods described above, namely the mechanical method, cannot deal with fiber tearing, the phototube method cannot deal with color changes, and the capacitance method cannot deal with changes in water content and cannot be fixed at a uniform speed. It was virtually impossible to eliminate the error.

In order to solve the above-mentioned situation, Japanese Patent Application Laid-Open No. 109707/1983 proposes a method of detecting loops in cut veneers during the unloading process by also employing an ultrasonic method.

However, although this has made it possible to detect the vertical position of the cut veneer to some extent in response to changes in the material of the cut veneer, the proposed method still It is impossible to automatically correct the discrepancy between the plate cutting speed and the unloading speed in constant speed control. Regarding correction control, a new drawback has arisen.

That is, firstly, the tip of the presser conveyor is brought into contact with the lower surface of the plane table on the nose bar side, and an appropriate space is provided above the slope of the plane table on the knife side and the delivery conveyor provided in connection with the slope of the plane table on the knife side. Therefore, the loop of the cut veneer is physically restricted. For this reason, if the cut veneer continues to loop in a moderately relaxed state, the cut veneer will be carried out onto the carry-out conveyor while being lightly abutted by the holding conveyor, but if the cut veneer remains in an excessively relaxed state, If a loop occurs, the space in which the cut veneer can loosen is limited by the presser conveyor, so the upper part of the cut veneer is held down and loops are formed in many layers, causing the veneer to loosen while being transported or The problem was that it folded over itself during winding.

The second drawback is that when the ultrasonic detector detects a loop in the tensile state of the cut veneer, this tension detection signal corrects the speed command signal of the uniform speed controller to the deceleration side. In other words, the tensile state of the cut veneer can only be resolved by reducing the speed of the unloading conveyor.Furthermore, this uniform speed control is time-limited control based on ON/OFF output, so accurate control due to the time lag is impossible. Control is difficult, and as a result, hunting is likely to occur. Therefore, with this constant speed control, there is a risk that a slack state may occur, and once a slack state occurs, it is impossible to automatically eliminate the slack state.

In view of the above, the present invention arranges a planer stand, which holds a cutting edge and a cutter, to be movable forward and backward with respect to a spindle rotation mechanism that imparts rotation to logs, and conveys a cut veneer to the lower part of the planer stand. The spindle rotation mechanism and the conveyor are each equipped with a separate variable speed motor, and an arithmetic circuit is provided to uniformly adjust the conveyance speed of the conveyor based on the spindle rotation speed and the amount of plane table movement. On the other hand, an ultrasonic detection method detects the amount of displacement of the cut veneer from the blade attachment side of the planer stand via the support at the upper open position of the connection formed between the planer stand and the conveyor. After hanging the container and inputting the displacement detected by the ultrasonic detector to a proportional controller, the controller is connected to a comparator attached to the arithmetic circuit, and the controller instructs the variable speed motor of the conveyor to increase/decelerate. An embodiment thereof will be described below with reference to the accompanying drawings. For convenience, the same reference numerals are given to the parts that have already been explained, and redundant explanation will be omitted.

The transport conveyor 8 is installed almost horizontally from the lower part of the planer stand 6 to the next process, the veneer winding process, and a certain level difference is formed at the connection part 15 between the planer stand 6 and the transport conveyor 8. It turns out. Therefore, the vertical displacement of the veneer 7 to be cut is likely to occur near the connecting portion 15, and the planer stand 6 has a tendency to displace the wood 2 held by the spindle rotation mechanism 3.
Since the veneer 7 is cut by moving a certain amount at a time,
The position of the connection part 15 has changed.

For this reason, the support 16 is made to protrude from approximately the center of the plane stand 6 on the side where the blade 5 is attached, in the conveying direction of the veneer 7.
A frame 17 adjustably attached to this support 16
The ultrasonic detector 18 is vertically suspended from the surface of the connecting portion 15 via the connecting portion 15 .

This ultrasonic detector 18 is equipped with a transmitting part 19a and a receiving part 19b, and can be easily calculated from the time required for the transmitted wave from the transmitting part 19a to reach the surface of the veneer 7 in the middle of cutting and the received wave reflected to the receiving part 19b. The position of the plate 7 is obtained from the detection signal.

The detection signal obtained by the ultrasonic detector 18 is once converted into a voltage and inputted to the proportional controller 20. The change in voltage with respect to the amount of displacement is regarded as a proportional characteristic.
Specifically, the cutting speed of the veneer 7 and the conveyor 8
In order to perform proportional control so that the circumferential speeds of the veneers are synchronized and the veneer 7 is conveyed in the most stable state as shown by the solid line in Figure 1, a table showing the proportional characteristics of distance and voltage in Figure 2 is used. In the middle, distance h point and voltage amount point e corresponding to this h point are used as base points, and the amount of vertical displacement of the veneer 7 due to the speed uniformity error is regarded as an increase or decrease in the voltage amount.

Therefore, when the veneer 7 is displaced upward and becomes in tension, the distance from point h in FIG. 2 becomes shorter, that is, the direction approaches the origin 0, so the voltage amount is e It is perceived as a negative direction from the point and becomes a deceleration signal, and conversely, when the veneer 7 is displaced downward and becomes bent, the direction increases from the point h, that is, the direction moves away from the origin 0. The voltage amount is taken as a positive direction from point e and becomes a speed-up signal.

The increase/decrease signal based on the voltage amount in the proportional controller 20 is inputted each time to a comparator 21 attached to the arithmetic circuit 13. , or the deceleration signals are compared, and the variable speed motor 14 of the conveyor 8 is controlled to follow, and the veneer 7 is
This is to constantly return to point h, which is the most stable transport position.

As described above, according to the present invention, the planer stand 6 holding the blade mouth 5 and the cutter 4 is arranged so as to be movable forward and backward with respect to the spindle rotation mechanism 3 that imparts rotation to the log 2, and the lower part of the planer stand 6 A conveyor 8 for conveying the cut veneer 7 is installed in series, and the spindle rotation mechanism 3 and the conveyor 8 are each equipped with variable speed motors 10 and 14 to control the spindle rotation speed and the amount of plane table movement. constitutes an arithmetic circuit 13 that makes the conveyance speed of the conveyor 8 uniform, and on the other hand,
At the upper open position of the connection part 15 formed between the planer stand 6 and the conveyor 8, an ultrasonic wave is applied to detect the amount of displacement of the cut veneer 7 from the side where the cutting edge 5 of the planer stand 6 is attached via the support 16. The type detector 18 is suspended, and the amount of displacement detected by the ultrasonic type detector 18 is controlled by the proportional controller 2.
After inputting 0, it is connected to the comparator 21 attached to the arithmetic circuit 13 and instructs the variable speed motor 14 of the conveyor 8 to increase/decelerate, so that the veneer 7
It is possible to reliably detect the amount of vertical displacement caused by the properties of the veneer, high-speed response errors, mechanical errors, etc., and to bring the veneer 7 into the most stable conveyance state.

Therefore, the drawbacks that occurred in the conventional method described above, namely, that the upper part of the cut veneer is pressed down in a limited space and loops are formed in many layers, and the loops are folded over each other during transportation or when winding up the veneer. In addition, since the tensile state of the cut veneer is resolved only by correcting the speed command signal of the uniform speed controller to the deceleration side using the tension detection signal, it eliminates the problem that the slack state cannot be automatically resolved. However, veneer 7 due to uniform speed error
This eliminates inconveniences such as tearing and folding of fibers during transportation, and allows the veneer 7 to be transported with minimum vertical displacement at all times.

[Brief explanation of drawings]

Figure 1 is a side view showing one embodiment of the present invention, Figure 2 is a side view showing one embodiment of the present invention;
The figure is an explanatory diagram showing proportional characteristics. 2... Log, 3... Spindle rotation mechanism, 6... Planer stand, 7... Single plate, 8... Conveyor, 10... Variable speed motor, 13... Arithmetic circuit, 14... Variable speed motor,
15... Connection part, 18... Ultrasonic detector, 20... Proportional controller, 21... Comparator.

Claims (1)

[Claims] 1 A planer stand, which holds a cutting edge and a cutter, is arranged so as to be movable forward and backward with respect to a spindle rotation mechanism that imparts rotation to the raw wood, and a conveyor for conveying the cut veneer is connected to the lower part of the planer stand. Separate variable speed motors are installed in the spindle rotation mechanism and the transfer conveyor, and an arithmetic circuit is configured to uniformly adjust the conveyance speed of the transfer conveyor based on the spindle rotation speed and the amount of movement of the planer stand. An ultrasonic detector that detects the amount of displacement of the cut veneer is suspended from the blade attachment side of the planer stand via the support at the open position above the connection formed between the machine and the conveyor.
After inputting the displacement detected by the ultrasonic detector to a proportional controller, the proportional controller is connected to a comparator attached to the arithmetic circuit, and the controller instructs the variable speed motor of the conveyor to increase/decelerate. Automatic tracking device in uniform speed conveyance process.