JPH04144701A - Control device for feeding cutting speed of running circular saw - Google Patents

Abstract

PURPOSE:To improve the safety and the protection of cutting system and the accuracy of cut face by a method in which the actual load-resistance of a spindle motor in working is detected, and it is compared with limit load value, and while the feeding speed of a circular saw is reduced and controlled correspondingly to the result, an alarm is issued. CONSTITUTION:The load resistance of a spindle motor 10 is detected by a loading current-detector 40, and it is converted into loading voltage V1 by a converting circuit 41. The converted voltage V1 is compared with the set voltages V2-V4 of each load-setting circuit 42, 44, 46 by comparing circuits 48-50. The compared result thereof is outputted to a speed-designating circuit 59 from gates 51, 53, 55 correspondingly to whether the detected loading voltage V1 is large or small for the set voltage V2-V1. That is, when the loading voltage V1 is larger than V2, a feeding motor 26 is driven by the commanded voltage Va of speed-commanding part 60, but when the voltage V1 is smaller than the voltage V2 in low loading, speed-reducing is commanded by respectively corresponding commanded voltages Vb-Vd or the speed commanding parts 61-63, and an alarm is sent by an informing means 67.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a cutting feed speed control device for a traveling circular saw, which controls the cutting speed in a deceleration direction when excessive cutting load resistance is detected. This system protects the safety of cutting systems such as circular saws and spindle motors, improves the precision of cutting surfaces, and warns operators to prompt them to take immediate action.

(Prior Art) Traveling circular saws, also known as panel saws and running saws, exist as processing machines for cutting large-format materials.

This type of processing machine is equipped with a main shaft motor for rotating the circular saw and a feed motor for cutting the circular saw, and takes into account the unit cutting amount of the circular saw on the workpiece, such as the cutting thickness. The cutting speed was artificially adjusted and even set.

In addition, an ammeter for the spindle motor is provided as an instrument to indicate cutting load resistance, and when visually checking the maximum load, the feed speed must be manually slowed down or stopped.6 (Problems to be Solved by the Invention) In cutting operations, it is desirable to set the cutting speed as high as possible in order to maximize efficiency, but the cutting load resistance during processing is determined by the amount of cutting per unit time. It increases proportionately,
Therefore, if the settings are not appropriate, the cutting load will be excessive. Moreover, even if the initial settings are appropriate, the cutting load increases as the sharpness of the saw decreases, and the accuracy of the cut surface deteriorates due to the decrease in rotation of the circular saw. In addition, if machining is performed under poor power conditions, the motor may lock up, resulting in burnout and shortening the service life.

In addition, since the ammeter that indicates the cutting load merely displays the information and does not take any active avoidance measures, considering the above circumstances, monitoring cannot be neglected, resulting in a large burden on the operator. Ta.

The present invention has been made by focusing on the problems of the prior art described above, and compares the actual load resistance of the spindle motor during machining with a limit load value, and changes the feed rate in the direction of deceleration according to the comparison result. This system not only controls the cutting process but also warns the operator using a notification means, and is intended to protect the safety of the cutting system, improve cutting surface accuracy, and reduce the burden on the operator.

(Means for Solving the Problems) When the cutting load resistance applied to the circular saw increases or decreases, the load on the spindle motor changes depending on the increase or decrease. The present invention has the advantage that if this load resistance is within an allowable range, the motor will not burn out, the cutting surface accuracy and the life of the cutting edge can be guaranteed, and the cutting amount can be reduced by suppressing the unreliable cutting feed rate. This method has been developed with the focus on the fact that the load resistance is small and good cutting surface accuracy can be obtained.

That is, the present invention provides a detection circuit that measures the load current of the spindle motor that drives a circular saw and detects the cutting load resistance from the detected value, a load setting circuit that sets the limit value of the cutting load resistance, and these detection circuits and load settings. It has a comparison circuit that compares the outputs of the circuits, a notification means activated by the output of the comparison results, a switching circuit, and a speed designation circuit that outputs each rotation command voltage corresponding to the switching position of the switching circuit. The circuit configuration is devised so that the output of the result gives an accurate warning to the operator and controls the feed motor in the direction of deceleration.

(Implementation (M)) One embodiment of the cutting feed speed control device for a traveling circular saw according to the present invention will be specifically described.

Fig. 1 is a front view of a panel saw equipped with this device. Fig. 2 is a side view of the panel saw. Frame 3 is a table board 4 attached to the front frame 2 with a slight space left in the vertical direction at the center of the front fixation area.
a and 4b (see Fig. 3) are a pair of mounting rib members on both sides that are built on the front frame 2 and are arranged corresponding to the above-mentioned spaces; 5 is a blade tip attached to the mounting rib members 4a and 4b; The cutting edge plate 5 is formed on the same plane as the table plate 3 described above, and is connected to the table plate 3.

The cutting edge plate 5 is made of a hard synthetic resin plate, light metal, or the like. Reference numeral 6 denotes a single saw running slit bored in the vertical direction of the upper J upper cutting edge plate 5, and this saw running slit 6 divides the cutting edge plate 5 into two cutting edge plates 5a and 5b on both sides. .

Reference numeral 7 denotes a horizontal ruler plate disposed at the lower part of the table plate 3 perpendicular to the saw running slit 6, and the workpiece W is placed on the table surface with its lower end received by the horizontal ruler plate 7.

Reference numeral 8 denotes a guide rail with an H-shaped cross section, which is supported by the upper and lower horizontal ribs 1a of the rear frame 1 and arranged on the back surface of the table board 3.
and arranged in parallel with appropriate spacing. Reference numeral 9 denotes a movable base disposed on the guide rail 8 so as to be movable up and down, and the cutting unit B is mounted on this movable base 9.

In FIGS. 3 and 4, reference numeral 10 denotes an arm 1 which is attached to a moving base 9 with the rotating shaft 11 horizontal, and a main shaft motor 12 is rotatably mounted on a bearing 13 concentric with the rotating shaft 11.
4 is a bearing tube provided at the free end of the arm 12; 15 is a horizontal saw shaft rotatably supported on the bearing tube 14; and 16 is a circular saw attached to one end of the saw shaft 15 via a flange 17.
A pneumatic cylinder 18 is connected to the arm 12, and when the piston rod is extended, the circular saw 16 is projected from the saw travel slit 6 onto the table 3, and when the piston rod is retracted, the circular saw 16 is projected onto the table 3. Immerse yourself in it from there.

Reference numeral 19 denotes a passive pulley 20 fixed to the saw shaft 15 and a rotating shaft 1.
When the circular saw 16 is in the retracted position, the transmission belt 22 is stretched between the driving pulley 21 fixed to the circular saw 16 and the driving pulley 21 fixed to the circular saw 16
This is a dust collection cover that surrounds the

E is a cutting feed means for moving the cutting unit B up and down;
A pair of sprockets 25 attached to the upper and lower ends of the guide rail 8, respectively, 3 and 24 are chains extended endlessly from the sprockets 23 and 24, and one end of this chain 25 is tied to the movable base 9. 26 is a feed motor consisting of a three-phase induction motor linked to the lower sprocket 24 via an appropriate transmission means. This feed motor 26 drives the chino 25 to run in the upward or downward direction.
Transfer the cutting unit B in the desired cutting feed direction.

F indicates a holding means for pressing and fixing the workpiece W to the table surface, and 27 indicates a support frame which is U-shaped in side view and is installed on the front side so as to correspond to and straddle the cutting edge plate 5. This support frame 27 The lower end is fixed to the table plate 3 via the slit cover 28, and the upper end is fixed to the table plate 3 via the attachment part 29.

Reference numeral 30 denotes a presser plate movably provided on the support frame 27 by means of a pair of upper and lower link arms 31. 32 denotes a cushion pad 33 attached to the contact surface with the workpiece W, and a cushion pad 33 is connected to one link arm 31. The pressure cylinder moves the presser plate 30 toward the table surface when the piston rod is extended, and moves the presser plate 30 away from the table surface when the piston rod is retracted.

The workpiece W is pressed and fixed to the table surface during the above-mentioned approach operation.

In the above configuration, after the workpiece W is supplied onto the horizontal ruler plate 7 and the cutting position is appropriately set, when the presser means F is operated at this position, the workpiece W is pressed and fixed to the table surface. In this state, when the circular saw 16 rotated by the spindle motor 10 is projected onto the table and moved downward from the top by the cutting feed motor 26, the workpiece W is linearly moved by the circular saw 16. Processed by cutting.

Here, the operator determines the cutting speed by the feed motor 26 by considering the unit cutting amount that can be machined according to the thickness, material, hardness, etc. of the workpiece, but in any case, the circular saw 16 is driven. The cutting load resistance of the spindle motor 10 increases in proportion to the cutting feed rate. If the above settings are not appropriate or if the sharpness of the circular saw 16 becomes dull, the cutting load becomes excessive and the rotation of the circular saw 16 decreases, causing various problems.

Therefore, by setting an allowable value for the cutting load resistance and decelerating the feed motor 26 when the actual cutting load resistance becomes larger than this value, an appropriate amount of cutting can be obtained and the circular saw 16 will It is possible to return to normal rotation and perform high-precision machining.8 Figure 5 shows a block circuit that controls the feed rate according to the cutting load resistance.

First, an operation switch 34 is connected to the three-phase power supply lines R, S, and T, and the main shaft motor 10, which is a three-phase induction motor that drives the circular saw 16, is connected in series to the load side of the operation switch 34. Further, a feed motor 26 consisting of a three-phase induction motor for feeding and controlling the cutting unit B by branching the same power lines R, S, and T, and a speed control circuit 35 of this motor 26 are controlled in series. The above-mentioned speed control circuit 35 comprises, for example, a pulse width modulation frequency converter (PWM), a rectifier 36 of a three-phase power supply, an intermediate circuit 37, an inverter 3
8 and a control section 39 that controls and adjusts these.

A control signal from a speed specifying circuit, which will be described later, is input to the control section 39, and the voltage and frequency supplied to the feed motor 26 are controlled in accordance with this signal.

40 is a load current detector that detects the load resistance of the spindle motor 10. 41 is a conversion circuit that receives the detection signal from the detector 40 and outputs a load voltage V1 according to its output.
42 is a suitable reference power supply and a variable resistor 4 connected to it.
The first load setting circuit configured as shown in FIG.

44 is a voltage set by a variable resistor 45 as well.

A second load setting circuit 46 is a variable resistor 47 that outputs
In the third load setting circuit which outputs the set voltage V4 according to the above, each set voltage is set to V2>V3>v4.

48 is a first comparison circuit that compares the load voltage v1 and the set voltage V2, and when V + > V 2, the logical value is "1".
", and when V i - < V 2, a logic value of "0" is output.

49 is a second comparator circuit which has a logical value of "1" when vl>v3
When V<V, a logical value of "0" is output. Also, 5
0 is a third comparison circuit, which outputs a logical value r 1 when V'+>V4, and a logical value 0 when Vl<V4.

Next, 51 is a first comparison circuit 48 and a second comparison circuit 49.
The first AND gate 52 inputs the output signal of
and a second AND gate 53 which receives the output signals of the third comparison circuit 49 and 50 as inputs. 3 AND gate 55 is a third AND gate 53 via a knot gate 56, a first AND gate 51 via a knot gate 57, and a third AND gate 53 via a knot gate 56.
A fourth AND gate 58 receives each output of the comparison circuit 50 as an input; 58 indicates each of the first, third, and fourth AND gates 51.5
This is a NOR gate that receives a 3.55 output signal as input.

These first to fourth AND gates 51.52.53.5
5, NOT gates 56.57 and NOR gates 58 form a switching circuit, and first, third, and fourth AND gates 51.5
3.55 and each output line a, b of the NOR gate 58
, c, and d selectively output a logical value "1". 5
9 is a speed specifying circuit that outputs a speed command voltage to the control section 39 of the speed control circuit 35, and each output line a of the above switching circuit
, b, c, and d, speed command units 60-63 are provided. Each speed command unit 60 to 63 outputs command voltages Va, vb, and V for driving the feed motor 26 at a predetermined rotational speed.
c and Vd are output.

The command voltage is set to Va>Vb>Vc>'Vd and Vd=O. 65 is an artificial setting means for setting the command voltages Va to Vd; 66 is a notification means connected to the first AND gate 51 via a NOT gate 67;
Outputs when the logical value is "0". This notification means generates sound or light and is recognized by the worker by hearing or seeing.

Since the configuration of the cutting feed rate control device according to the present invention is as described above, if the cutting load resistance applied to the circular saw-16 is within the limit value, that is, in a state of V,>V2, the first AND gate 51 Since the output signal has a logical value of "1", the command voltage Va is output from the speed command section 60 to the speed control circuit 35 at this time. The feed motor 26 is given a cutting feed speed corresponding to this command voltage Va.

Also, if the cutting load resistance increases for some reason during machining at the above feed rate and becomes v , <'v 2, the output of the first AND gate 51 becomes a logical value "0" and the Then, the output of the third analogue lower 53 becomes the logical value "1".
”. Therefore, the command voltage vb is output from the speed command section 61 to the speed control circuit 35. In the above, 'V
Since a>'Vb, the feed motor 26 is decelerated and the cutting feed rate is reduced. Therefore, the cutting load resistance of the circular saw 16 is reduced.

Further, when the output of the first AND gate 51 becomes a logical value "0", the notification means 66 operates and outputs a warning signal,
Warn workers.

When the cutting load resistance is reduced in this way, the circular saw 16 recovers its rotation to a normal state, and V + > V 2. However, taking into account chipping of the cutting edge during the overload, etc.
The cutting feed rate is fixed at a reduced rate.

Furthermore, during the above-mentioned deceleration, if the cutting load resistance is still large and V + < V 3, the fourth AND gate 55 outputs a logical value of "1", so in this case, the command voltage Vc Cutting feed will be performed at the low speed determined by .

In this way, the feed rate is set to a low speed each time excessive cutting load resistance is detected, so that no strain is placed on the cutting system, such as the circular saw or the spindle motor, allowing safe work. Note that when V, (V) and the output signal from the NOR gate 58 becomes a logical value "1", the cutting feed is stopped.

It should be noted that a healthy work environment can be ensured if the operator inspects, adjusts, and replaces the setting of the cutting speed, the sharpness of the saw, etc. when the above-mentioned warning signal is output.

Further, in the above embodiment, the cutting load resistance is measured by detecting the load current of the spindle motor.

However, it is also possible to detect increases and decreases in the rotational speed of the circular saw with a rotation detector and determine the cutting load resistance from this.

(Effects of the Invention) According to the present invention, a limit value is set for cutting load resistance, and when an actual load resistance exceeding this limit is detected, a warning is given to the operator, and the cutting feed rate is controlled in the direction of deceleration. This is what I did. Therefore, there is no strain on the cutting mechanism such as the circular saw and the spindle motor, allowing highly accurate machining work to be performed.

Additionally, abnormal situations can be recognized and inspected quickly to improve a healthy work environment.

[Brief explanation of the drawing]

The drawings show an embodiment of the cutting feed speed control device for a traveling circular saw according to the present invention, and FIG. 1 is a front view of a panel saw equipped with this device. FIG. 2 is a side view as well. 4 is a cross-sectional plan view showing a partially enlarged view; FIG. 4 is a front view; and FIG. 5 is a block circuit diagram. A: Main body frame B: Cutting unit E. Cutting feed means F: Holding means W: Processed material 3: Table plate 5 (
5a, 5b): Cutting edge plate 6 Slit for saw travel 9: Moving base 10: Spindle motor 16: Circular saw 26: Feed motor 35: Speed control circuit 36: Rectifier 37: Intermediate circuit 38: Inverter 39: M part 40: Rotation speed detector 41: Conversion circuit 42: First load setting circuit 4
3.45.47: Variable resistor 44: Second load setting circuit 46: Third load setting circuit 48: First comparison circuit 49: Second comparison circuit 50: Third comparison circuit 51
;First AND gate 52: Second AND gate 53
:3rd AND gate 55:4th AND gate 5
8: Noah gate 59: Speed designation circuit 60 to 63: Speed command section 65 Artificial setting means 66: Notification means

Claims (1)

[Claims] A traveling circular saw that protrudes from a slit for saw travel and cuts a workpiece held on a table surface by the circular saw, comprising: a main shaft motor that rotationally drives the circular saw; , a feed motor for driving the circular saw is provided separately, and a detector for detecting the cutting load resistance, a conversion circuit for outputting a load voltage signal in response to the output of this detector, and a cutting A load setting circuit that sets a limit value of the load resistance and outputs a voltage signal according to the set value, and a comparison circuit that compares the voltage signal of these conversion circuits and the voltage signal of the load setting circuit,
The output of this comparison circuit operates the notification means, and
The feed motor side is provided with a speed control circuit that controls its rotation speed, and a speed designation circuit that outputs each rotation command voltage to this speed control circuit, and each speed command part of this speed designation circuit is connected to the comparison circuit. A cutting feed speed control device for a traveling circular saw, characterized in that the cutting feed speed control device for a traveling circular saw is connected to a speed control circuit in a switching manner based on an output signal, and is configured to control the power voltage and frequency supplied to a feed motor in the direction of reducing it.