JPH0880504A - Lumber processing machine - Google Patents

Abstract

PURPOSE: To provide a lumber processing machine which can prevent a motor from being damaged by a fire by overload without locking the motor and avoid a hazard in handling a processing edged tool at the time of locking the motor in the middle of cutting and prevents a loss in a commodity value of a work from being generated in either single operation or compound operation of the processing edged tool in the lumber processing machine having a plurality of the processing edged tools. CONSTITUTION: A driving current of a cutter motor 9 is detected by a detector 15, which is converted into a voltage signal by a conversion circuit 16, size comparison of which with a voltage value corresponding to an overload current pre-established by a comparator circuit 17 is performed, when it is revealed that the value exceeds the set value (if it is overload), a signal is applied to a timer 18 and when a time is longer than a set time of the timer 18, a signal is applied to an OR gate. As for a router motor 14, it has a similar circuit and a signal is applied to the OR gate. Either side of the above-mentioned signals is applied to the OR gate 23, a change-over contact point 31 is changed over and material feed is reduced to a low speed operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a feeding speed of a wood working board having a plurality of working blades and feeding a working material by a feeding device.

[0002]

2. Description of the Related Art A conventional wood processing board is disclosed in Japanese Patent Laid-Open No. 1-2570.
As described in No. 01 publication, the load current of the motor of one cutting blade is detected by the detecting means, and when the load current is equal to or less than the preset upper limit value, the material is fed at medium speed and exceeds the upper limit value. You were supposed to drive at a lower speed. In addition, as described in Japanese Utility Model Application No. 58-144429, the load state of one rotary blade is detected by a detector, and the phase of the power supply of the material feeding device is controlled automatically so as not to exceed a predetermined limit value. I was supposed to make adjustments.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In Japanese Patent Laid-Open Publication No. 1-Gazette, a load state of a motor for rotating a cutting blade is detected by a detection unit, and when a predetermined value set in advance is exceeded, the material feeding device is operated at a low speed so as not to exceed the predetermined value. However, even if the sharpness of the blade deteriorates even at this low speed operation, if an overload that exceeds a predetermined value occurs, such as when the cutting blade bites into the processed material, it stops and the motor locks. I will end up. Also,
In a wood processing board having a plurality of processing blades and capable of composite cutting, even when one processing blade is in the locked state, another processing blade is still in a rotating state, which is extremely dangerous. Further, it takes a lot of time to remove the processed material from the state, not only the working efficiency is significantly deteriorated, but also the commercial value as the processed material is lost. Further, when it is determined whether the preset value is exceeded, the time when the preset value is exceeded is not determined. Since an excessive current that exceeds a predetermined value instantaneously flows, it may be judged as an overload and an erroneous operation may occur such that the feeding speed is reduced. Also, single phase 1
When a 00V power supply is used, the allowable upper limit of the usable current is low. Therefore, when multiple motors are used at the same time, each motor cannot be used up to the maximum output. There were problems such as causing the descent and making it easier for the motor to lock.

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to lock the motor even under conditions where the machine blade is likely to be overloaded, such as a node of the machined material, a hard machined material, and deterioration of the sharpness of the machined blade. Continues to cut without preventing burnout due to overload of the motor, and if any motor locks due to simultaneous machining with multiple machining blades, rotation of other motors (rotation of machining blade) Is to stop safely and avoid danger. Furthermore, the excessive current that flows instantaneously when the motor is started is mistakenly determined as an overload current, and the feeding device is not malfunctioned.

[0005]

The above object is to provide a detection means for detecting load currents of a plurality of machining blade motors for each motor (M ₁ , M ₂ , ...), so that the load current can be preset for each motor. If any one or more of the set upper limit values (I ₁ , I ₂ , ...) Are exceeded and the preset time (T ₁ , T ₂ , ...) For each motor is exceeded, Upper limit values (I ₁ , I ₂ , ...) And time (T ₁ ,
T ₂ ,. ． ． ) Is reduced to a low speed operation so that the upper limit value (I ₁ ,
I ₂ ,. ． ． ) And time (T ₁ , T ₂ , ...) Are exceeded by providing a motor for the machining blade and a control means for stopping the feeding motor.

Further, the sum of the load currents (i ₁ + i ₂ + ...) Of the plurality of machining blade motors exceeds a preset upper limit value (Imax) regulated by the power supply capacity, and the upper limit value thereof is exceeded. When the time exceeding (Imax) exceeds a preset time (Tmax), the material feeding is reduced to low speed operation so as not to exceed the upper limit value (Imax) of the current,
Further, when the upper limit value (Imax) and the time (Tmax) are exceeded even in the low speed operation, it is achieved by providing a motor for the machining blade and a control means for stopping the feeding motor.

[0007]

In the above structure, the load current of any of the machining blade motors has a preset upper limit value (I ₁ ,
I ₂ ,. ． ． ) And its upper limit (I ₁ ,
I ₂ ,. ． ． ) Is exceeded for a preset time (T ₁ , T ₂ , ...), the speed is reduced to low speed operation so as not to exceed the upper limit (I ₁ , I ₂ , ...). And continue cutting. Further, even after the low speed operation, the upper limit value (I ₁ , I ₂ , ...) And the time (T ₁ ,
T ₂ ,. ． ． ) Again, stop the motor and feeding.

If the sum of the load currents (i ₁ + i ₂ + ...) Of a plurality of machining blade motors exceeds a preset upper limit value (Imax), the upper limit value (Imax) is not exceeded. Then, reduce the material feeding to low speed operation and continue cutting.
Further, even after the low speed operation, the upper limit value (Ima
x), and when the time (Tmax) is exceeded again, the motor and feeding are stopped.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view of a main body showing an embodiment according to the present invention,
FIG. 2 is a side view of FIG. In the figure, a table 2 is provided on a base 1, and above the table 2, a head 6 having a plurality of material-sending rollers 5 that is driven to rotate by a material-sending motor 4 and that sends a processed material 3 is disposed. A feeding path is formed between the table 2 and the head 6. The head 6 is provided with an elevating handle 7, and the head 6 can be raised and lowered via a feed screw 8 by rotating the elevating handle 7. An opening is provided at the center of the upper surface of the table 2, and the blade of the cutter 10 which is rotationally driven by the cutter motor 9 is projected from this opening by a link mechanism or the like, so that the amount of projection can be adjusted. ing. A guide 11 that guides the feeding of the processed material 3 is fixed to the table 2. A router 13 that rotatably projects the router bit 12 from the guide 11 is provided on the rear side of the table 2 in the material feeding direction. The router 13 is guided by a guide member such as a dovetail mechanism (not shown) so as to be movable in the vertical direction, and the amount of protrusion from the guide 11 can be adjusted. The router 13 is rotationally driven by the router motor 14.

Before cutting, the motor 9 or 1
Since No. 4 is not in the overload state, the relay contact 36 is closed, and the switch SW1 and SW2 are turned on so that the operation is possible. When the switch SW1 is turned on, the power supply voltage is applied to the cutter motor 9 and rotationally driven, so that the cutter 9 is rotated. Further, when the switch SW2 is turned on, the power supply voltage is applied to the router 14 so that the router 14 is rotated and rotated. Switch S
By turning ON one or both of W1 and SW2, it is possible to perform an independent operation of rotating one of the blades or a combined operation of rotating both of the blades. Switch S
When either one of W1 and SW2 is turned on, the power supply voltage is applied to the material feeding motor 4 through the triac 25 for phase control, and the tacho generator 35 rotates the material feeding speed corresponding to the indicated value of the volume 28. While detecting the speed, the comparator 29 compares them and the phase control circuit 30 controls the conduction of the triac 25 so that a predetermined feeding speed can be obtained. Generally, when used with a single-phase commercial power source, in the case of grooving or router processing as shown in this embodiment, the feeding speed is adjusted within a range of 1 to 5 m / min.

A detector 15 for detecting the load current of the cutter motor 9 and a conversion circuit 16 for converting an output signal from the detector 15 into a voltage signal proportional to the load current are provided, and an output voltage value V1 from the conversion circuit 16 is provided. It is applied to the non-inverting input of the comparator circuit 17. On the other hand, a voltage value V ₂ corresponding to the overload current I1 of the cutter motor 9 is given to the inverting input of the comparison circuit 17 in advance, and the load state is judged by comparing the magnitudes of the voltage values V ₁ and V ₂ . When V ₁ ≦ V ₂ , the overload has not been reached, so a logic “0” is output, and when V ₁ > V ₂ , it is determined that an overload has been reached and a logic “1” is output. The timer 18 monitors the time Ta during which the logic "1" is output. The timer 18 has a preset time T ₁ , and when Ta> T ₁ , the timer 18 outputs a signal of logic “1”. This time T1 is longer than the time required for the cutter motor 9 to start, and the cutter 10
Therefore, even if the load increases due to local knots during cutting of the workpiece, it is set to a few seconds so that it is not easily judged as an overload.

Similarly, a detector 19 for detecting the load current of the router motor 14 and a conversion circuit 20 for converting the output signal from the detector 19 into a voltage signal proportional to the load current are provided, and the output from the conversion circuit 20 is provided. Comparing circuit 2 with voltage value V ₃
1 to non-inverting input. Meanwhile advance given to overload current inverting input of the pre-comparator circuit ₂ 1 a voltage value V ₄ corresponding to the I ₂ of the router Motoru 14 determines the load state by comparing the magnitude of the voltage value V ₃ and V ₄ ing. When V ₃ ≦ V _4, the logic “0” is output because the overload has not been reached, and V ₃ >
When it is V ₄ , it is judged that the overload has been reached and the logic is “1”.
Is output. The timer 22 monitors the time Tb during which the logic "1" is output. The timer 22 has a time T in advance.
_{When 2} is set and Tb> T ₂ , the timer 22 outputs a signal of logic "1". This time T ₂ is larger than the time required for the router motor 14 to start up in the same way as the time T ₁ , and even if the load increases due to a local node during cutting of the workpiece by the router 12, it is easily overloaded. It is set to a few seconds so that it will not be judged.

The output signals of the timer 18 and the timer 22 are input to the OR gate 23, and when either one of the timers 18 and 22 has the logic "1", the OR gate 23.
The output of is inverted from logic "0" to logic "1". The flip-flop 24 is set by this inversion signal and a signal of logic "1" is output. Receiving the signal of logic "1", the switching contact 31 is switched from 31b to 31a, and the resistor 32 and the resistor 3 are connected.
Reduce to a low speed set by a partial pressure value of 3. This low speed may be set to the minimum value of the material feeding speed adjusted by the volume 28 or less, and it is appropriately set in consideration of the relationship between the working blade and the working material. The cutter 10 or the router 1 is operated even after the load is reduced by operating at a lower speed.
When the cutting load of _{No. 2} increases and one of the motors becomes overloaded, V ₁ > V ₂ or V ₃ > V ₄ is established as described above, and the timers 18 and 22 regulate it. OR gate 23 when time T ₁ or T ₂ is exceeded
The output of is inverted again from logic "0" to "1". Upon receiving this inversion signal, the flip-flop 34 is set and outputs the logic "1", so that the relay coil 36 is energized to open the relay contact 36, and the motors 4, 9 and 1 are opened.
The power supply to 4 is cut off. As a result, even if an overload state occurs again at low speed operation, the operation can be stopped safely without damaging the processing blade or the drive part.

In the above explanation, the explanation has been advanced on the assumption that the cutting work by each working blade can be sufficiently loaded until the overload of the motor is reached. However, when a sufficient power supply capacity cannot be obtained like a single-phase 100V power supply, it is impossible to utilize each motor to the maximum output for cutting. Therefore, the load current i ₁ of the cutter motor 9 is detected and the load current i ₂ of the router motor 14 is detected similarly to the voltage value V ₁ obtained by the conversion, and the voltage value V ₃ obtained by the conversion is calculated. The sum (V ₁ + V ₃ ) is added to the non-inverting input of the comparator 27 as the value added by the adder 26. The voltage value corresponding to the maximum current value (Imax) that can be used as the power supply capacity is set to V ₅ and the comparator 2
It is given to the inverting input of _{No. 7} and the magnitudes of the voltage values V ₁ + V ₃ and V ₅ are compared to determine the load state with respect to the power supply capacity. When (V ₁ + V ₃ ) ≦ V ₅ , there is no overload and a logic “0” is output, and (V ₁ + V ₃ )> V
When it is ₅ , it is judged that an overload has been reached and a logic "1" is output. The timer 37 monitors the time Tc when this logic is “1”. The timer 37 has a preset time (Tm
ax) is set and Tc> Tmax, the timer 37 outputs an inversion signal from logic “0” to logic “1”. This time (Tmax) is also set to several seconds based on the same idea as the times T ₁ and T ₂ described above. This inverted signal is input to the flip-flop 24 via the OR gate 23, and the flip-flop 24 sets and outputs a signal of logic "1". Therefore, similarly to the above, the switching contact 31 can be switched from 31b to 31a by receiving the signal of the logic "1", and the speed can be reduced to the low speed set by the divided voltage value of the resistors 32 and 33.

Furthermore, the cutting load of the cutter 10 or the router 12 increases even after the low-speed operation to reduce the load state, that is, the value of (V ₁ + V ₃ ) also increases, and (V ₁ + V ₃ )>
V ₅ and the time regulated by the timer 37 (Tma
x), the flip-flop 34 is set via the OR gate 23 to output the inverted signal of the logic “0” to “1”, and the logic “1” is output.
The relay coil 36 is energized to open the relay contact 36b,
The power supply to the motors 4, 9 and 14 is cut off.

As described above, in the embodiment, the load state is determined by the method of detecting the load current of each motor, but the same effect can be obtained by the method of detecting the rotation speed of the motor. Further, the control means is composed of an analog circuit and a logic circuit, but it is also possible to perform this control by a control program using a microcomputer. The above-mentioned control means is the part surrounded by the broken line 38 in FIG. 3, the conversion circuit is 16, 20, and the comparison circuit is 1.
7, 21, 27, 29, the timer is 18, 22, 37,
30 for phase control circuit, 25 for TRIAC, 2 for adder
6, flip-flops 24, 34, relay coil 3
6, the relay contact 36b. In the present embodiment, the case where the number of processing blades is two has been described, however, 3
The circuit may be configured with the same idea even when there are two or more cases. As described above, the motor is not locked even in the combined machining by the two motors of the cutter motor 9 and the router motor 14, so that it is possible to prevent the drive machine part and the machining blade from being damaged, and to prevent the motor from burning, and to start the motor. Incorrectly distinguishing the current as an overload current,
The control circuit no longer malfunctions.

[0017]

According to the present invention, the load currents of a plurality of motors are respectively detected, and the detected current value exceeds any one or more upper limit values preset for each motor, and the upper limit of the currents is exceeded. If the time exceeding the value exceeds the preset time for each motor, the feeding speed is reduced to a low speed operation that does not exceed the upper limit value of the current, and the upper limit value of the current is maintained even after the low speed operation. If it exceeds the limit, multiple motors and feeding are stopped, so it is possible to prevent burnout due to overload of the motor without locking the motor, and to prevent the excessive current that flows when the motor starts up from the overload current. By mistake, it was possible to prevent the operation of slowing down the feeding speed even though it was not overloaded.

[Brief description of drawings]

FIG. 1 is a front view of a main body showing an embodiment according to the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a block diagram.

[Explanation of symbols]

3 is a processed material, 4 is a feeding motor, 9 is a cutter motor,
14 is a router motor, 15 and 19 are detectors, 16 and 2
0 is a conversion circuit, 17, 21, 27 and 29 are comparison circuits, 1
8, 22, 37 are timers, 30 is a phase control circuit, 25
Is a triac, 26 is an adder, 24 and 34 are flip-flops, 36 is a relay coil, and 36b is a relay contact.

Claims (3)

[Claims] 1. A table on which a workpiece is placed, and an elevating body facing the table, a plurality of machining blades on either the table or the elevating body, and a plurality of motors for rotating the machining blade. , And a wood processing board which is provided with a material feeding device capable of adjusting the feed speed of the processed material and which can be operated independently by any one of the plurality of processing blades or by a compound operation for performing a plurality of processing. In the above, detection means for detecting the load current of the plurality of machining blade motors (M ₁ , M ₂ , ...) Are provided for each motor, and the detection means corresponds to the overload value of the load current for each motor. The upper limit value (I ₁ , I ₂ , ...) Is set in advance, and any one or more of the upper limit values (I ₁ , I ₂ , ...) Are exceeded during cutting of the workpiece, and The upper limit value of the load current of the motor (I ₁ ,
I ₂ ,. ． ． ) Exceeds the preset time (T ₁ , T ₂ , ...) For each motor, the speed of the material feeding device is set to the upper limit value (I ₁ , I ₂ ,. (...)
So as not to exceed the upper limit of the current (I ₁ , I ₁ ,
I ₂ ,. ． ． ) And the time (T ₁ , T ₂ , ...) Again, a wood processing board provided with a motor for the cutting blade and a control means for stopping the material feeding device, respectively. 2. A sum total (i ₁ +) of load currents (i ₁ , i ₂ , ...) Of the respective motors that rotate the processing blade.
i ₂ +. ． ． ) Exceeds a preset maximum value (Imax) and the time during which the maximum value (Imax) is exceeded exceeds a preset time (Tmax), the current exceeds the upper limit value (Imax). If the material feed rate is reduced to low speed operation to continue cutting, and the maximum value (Imax) and time (Tmax) are exceeded again even after the speed is reduced to low speed operation, the motor of the machined blade and the The wood processing board according to claim 1, further comprising control means for stopping the lumber device. 3. The upper limit value (Imax) according to claim 2.
Is set to the maximum value of the power supply capacity of the wood processing board.