JPH0664802U - Tabletop cutting machine - Google Patents

Abstract

(57) [Abstract] [Purpose] The object of the present invention is to improve the life of the endless belt and to improve the quality of the cut surface of the material to be cut in a tabletop cutting machine using the endless belt for the power transmission means of the motor. It is to improve the efficiency of workability. In a tabletop cutting machine using an endless belt as a power transmission means of a motor, a magnetic pickup 20 serving as a rotation speed detection means and a resistor 24 serving as a load current detection means are provided on a motor shaft, and a signal of each detection means is provided. In response to this, a control circuit 29 for controlling the triac 23 is provided, and further, when the motor power is cut off, the motor shaft serving as a braking means of the motor and the endless belt and the cutting tool shaft and the endless belt do not slip. By providing the motor with the dynamic braking coil 25 to be stopped, the number of rotations and the torque of the motor at the time of starting, disconnecting and stopping the motor are controlled.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a tabletop cutting machine using an elastic endless belt as a power transmission means of a motor.

[0002]

[Prior art]

 Conventionally, rotation control for an electric motor is disclosed, for example, in Japanese Patent Laid-Open No. 61-180593. This is a motor that performs forward / reverse rotation and detects the number of rotations and the load current to keep the number of rotations of the motor constant and to provide an adjusting device that adjusts the motor load current so that the number of rotations can be adjusted to be constant Is. Here, as an example, the present invention is applied to a processing machine such as a drill, but this control was the rotation control of the motor limited only to the processing load. Further, it is well known to use an endless belt as a power transmission means of a motor. However, there is no one that simultaneously controls the motor torque and rotation speed corresponding to the allowable transmission torque of the endless belt.

[0003]

[Problems to be solved by the device]

 In the conventional motor control, in a tabletop cutting machine that uses an elastic endless belt as a power transmission means, the transmission torque of the endless belt is usually limited. Slip occurs between the blade shaft and the endless belt. In particular, slips frequently occurred when the motor was started, suddenly stopped, and overloaded, leading to early wear of the endless belt. Also, in the tabletop cutting machine, when the power supply to the motor is cut off, a brake device is provided to prevent the cutting blade from rotating freely, and the motor is stopped suddenly. Repeating this sudden stop markedly caused early wear of the endless belt. Furthermore, in a tabletop cutting machine, the rotational speed of the cutting blade axis changes depending on the actual load during cutting, which causes a difference in the amount of cutting due to the change in rotational speed, and a saw mark, which is generally called, is generated. However, it deteriorated the finish of the cut surface. For this reason, the worker slowly adjusts the cutting descent speed so that the rotational speed of the cutting blade shaft does not suddenly change, which deteriorates workability and work efficiency. The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, prevent slipping on the endless belt, improve the finishing quality of the cut surface of the material to be cut, and improve workability and work efficiency during cutting. To improve.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the tabletop cutting machine of the present invention is as follows. An elastic endless belt is used as the power transmission means of the tabletop cutting machine, and a rotation speed detection means for detecting the rotation speed of either the motor or the rotation drive section and a load current detection means for detecting the load current of the motor. The motor control means for controlling the rotation speed and the torque by performing a soft start for temporarily increasing the electric power supplied to the motor in response to the signals from the rotation speed detection means and the load current detection means. In addition, the motor is equipped with braking means to stop the rotation of the motor when there is no slip between the motor shaft and the endless belt or between the cutting blade shaft and the endless belt when the motor power is cut off. The purpose is to control the number and torque relatedly.

[0005]

[Action]

 When the motor is started, the tabletop cutting machine configured as described above causes the motor control means to soft-start the motor to slowly start the rotation of the motor, and the motor shaft and the endless belt and the cutting blade shaft and the endless belt are connected. To transmit the power so as not to slip, and then feed back the signal of the rotation speed detection means to the motor control means until the rotation speed of the motor reaches the rotation speed preset in the motor control means. Controls the number of rotations of the motor. At this time, the rotation speed preset as the no-load rotation speed is set to the same level as the actual load rotation speed of the material to be cut. Therefore, when cutting the material to be cut, the rotation speed of the cutting blade does not change, saw marks do not occur, and the finish quality of the cut surface improves. Further, since the load current is detected by the load current detection means of the motor, when the motor load detects a load that exceeds the allowable transfer torque of the endless belt while cutting the material to be cut, the motor control means It limits the input current and reduces the torque of the motor. This can prevent the endless belt from slipping during the cutting of the material to be cut. Further, when the power is cut off while the motor is rotating, the motor braking is stopped by the braking means of the motor when the slip does not occur between the motor shaft and the endless belt or between the cutting blade shaft and the endless belt. As a result, the endless belt does not slip and the inertial rotation of the motor can be stopped.

[0006]

【Example】

 An embodiment according to the present invention will be described with reference to FIGS. 1 is a left side view showing an embodiment of a tabletop cutting machine according to the present invention, FIG. 2 is a partial sectional front view of FIG. 1, FIG. 3 is a partially enlarged sectional view of FIG. 2, FIG. 4 is a block circuit diagram, and FIG. FIG. 4 is a motor rotation speed-torque, rotation speed-load current characteristic diagram. In the figure, a fence 3 supporting a material 16 to be cut is fixed to the rear of the base 1, and a turntable 2 is embedded in the center of the base 1 so as to be horizontally rotatable. A holder shaft 4 provided on the rear side of the turntable 2 supports a holder 6 so that the holder 6 can be tilted left and right. A clamp lever 5 for fixing the inclined position is formed in a long hole (not shown) formed in the holder 6 and fitted into a screw hole formed in the rear of the turntable 2. Above the holder 6, a cutting blade portion 8 having a cutting handle 14 is pivotally supported on the upper surface of the base 1 so as to be vertically swingable about a shaft 7 as a fulcrum. The cutting blade unit 8 is composed of a cutting blade 10 and a motor housing 15 that rotationally drives the cutting blade 10. The power of the motor unit 11 is transmitted from the motor shaft 12 to the cutting blade 10 via the elastic endless belt 13 and the cutting blade shaft 9. The motor portion 11 is provided with a magnet holder 18 fixed to the motor shaft 12 at the end of the motor shaft 12 opposite to the endless belt 13 and a magnet ring 17 rotating with the motor shaft 12. A plurality of magnetic poles are magnetized on the magnet ring 17. A controller box 19 serving as motor controller means for controlling the motor is provided on the magnet ring 17 side of the motor housing 15, and the magnetic pickup of the controller box 19 detects magnetic poles of the magnet ring 17 and serves as rotation speed detection means. Is provided. The motor unit 11 is generally called a direct-winding commutator motor. An armature 22 is connected in series with the field winding 21, and a triac 23 for controlling a current flowing through the field winding 21 and the armature 22. A resistor 24, which serves as a load current detecting means, is connected and housed in the controller box 19. Further, the dynamic braking coil 25 serving as a braking means is provided so as to form a closed circuit in series with the armature 22 and the field winding 21a when the power is cut off by the switch 26. The dynamic braking coil 25 is connected in series with a field coil 27 that generates a field in the direction of braking the armature 22 and a field coil 28 that generates a field in the direction opposite to the direction of braking. It is formed. The output signals of the magnet pickup 20 and the resistor 24 are connected to the control circuit 29 in the controller box 19, and the output signal of the control circuit 29 is connected to the gate of the triac 23 to control the triac 23. The control circuit 29 has a circuit for gradually increasing the conduction angle of the triac 23 when the power is turned on, or the data and the rotational speed N of the actual cutting load and the torque value T of the allowable transmission torque of the endless belt, or the torque T. The load current value I to be set is set. A current gradually flows through the armature 22 by the triac 23, and the rotation of the motor shaft 12 is temporarily increased to be a soft start. The power of the motor shaft 12 rotates the cutting blade 10 via the endless belt 13 and the cutting blade shaft 9. When the motor shaft 12 rotates, the magnet ring 17 rotates, and the magnet pickup 20 detects the rotation of the magnet ring 17 and outputs a signal to the control circuit 29. The control circuit 29 compares the number of revolutions N set in advance with the number of revolutions from the magnet pick-up 20, and matches the set number of revolutions of the actual cutting load to prevent overshoot and ringing of the number of revolutions. The triac 23 is controlled to control the current flowing through the armature 22 to control the rotation of the motor shaft 12. Thereby, the rotation of the cutting blade 10 is controlled. The characteristics of the motor unit 11 of this embodiment are shown in FIG. In FIG. 5, the wavy line portion is the motor characteristic when the control is not performed, and the solid line portion is the motor characteristic when the control is performed. The rotation speed of the motor shaft 12 is regulated to N and the torque is regulated to T. . Next, the handle 14 is gripped and the cutting blade portion 8 is swung downward to cut the material 16 to be cut. As for the load current of the motor at the time of disconnection, the voltage generated by the current flowing through the resistor 24 is detected, and the load current is detected by inputting it to the control circuit 29. In the embodiment, the increase / decrease in load current is proportional to the motor shaft torque due to the characteristics shown in FIG. As a result, by detecting the load current, the motor shaft torque can be indirectly detected. Therefore, the control circuit 29 converts the motor load current at the time of disconnection into the motor shaft torque via the resistor 24, compares it with the torque value T of the allowable transmission torque of the endless belt 13 which is set in advance, and The triac 23 is controlled so as not to exceed the allowable transmission torque of the belt 13. Further, when the motor power is cut off by the switch 26, the armature 22 and the dynamic braking coil 25 become a closed circuit, the kinetic energy of the armature 22 generates a voltage, and a current flows in the dynamic braking coil 25, so that the armature is closed. The rotation of the armature 22 is smoothly braked by the field coil 27 that controls the motor 22 and the field coil 28 that is opposite to the direction in which the braking is applied, and the motor shaft 12 and the endless belt 13 are disconnected or disconnected. The rotation of the armature 22 stops, the rotation of the motor shaft 12 stops, and the rotation of the cutting blade shaft 9 via the endless belt 13 stops during the time when no slip occurs between the blade shaft 9 and the endless belt 13. As an effect peculiar to one embodiment of the present invention, since the handle 14 is provided at the extension of the cutting blade portion 8, there is no recoil at the time of starting the motor due to the soft start at the time of starting the motor, and it is possible to reduce the It has the effect of making noise. Further, since the distance between the motor shaft 12 and the cutting blade shaft 9 is increased by the endless belt 13, there is an advantage that a large tilt angle can be obtained when the holder 6 is tilted left and right. 1 and 2, the endless belt is an elastic body, but it may be a V belt, a poly V belt, or the like, or a steel belt such as an iron belt. Although the magnet ring 17 and the magnet pickup 20 are used as the rotation speed detection means, a rotation detector such as a rotary encoder may be used. Further, the rotation speed detecting means may detect the rotation of the cutting blade shaft 9, the endless belt 13 and the like as well as the end of the motor shaft 12. The control circuit 29 may be configured by a microcomputer, a phase control IC, or the like. The motor section 11 uses a series-wound commutator motor, but an induction motor may also be used. The braking means 25 is formed by a power generation braking coil 25 that includes a field coil 27 that generates a field in the braking direction and a field coil 28 that generates a field in a direction opposite to the braking direction, and performs a gentle stop. However, the resistance value of the dynamic braking coil 25 may be simply increased to weaken the braking field, or the motor shaft 12 and the cutting blade shaft 9 may be tensioned by the belt to mechanically apply a gentle braking. Absent. The rotation speed N and the torque value T preset in the control circuit 29 may be set at a high efficiency point or a high cutting efficiency point in terms of motor characteristics. As the triac 23 that controls the motor current, a thyristor, a FET, a transistor, an inverter control, or the like may be used.

[0007]

[Effect of device]

 According to the present invention, in a tabletop cutting machine using an endless belt as a power transmission means of a motor, a rotation speed detection means and a load detection means are provided, and signals of these detection means are provided to control the motor rotation speed and torque. The brake means is provided to control the motor torque when the motor is stopped and to stop the motor when the motor is stopped.Therefore, the motor rotation speed and torque can be controlled in all steps from the motor start to the motor stop. It is possible to set the proper torque and rotation speed without slip between the motor shaft and the endless belt and between the cutting blade shaft and the endless belt, so that the life of the endless belt can be extended. . In addition, since the rotation speed feedback control is performed so that the rotation speed during cutting does not change suddenly, there is no difference in the cutting amount due to fluctuations in the rotation speed. It is possible to improve workability and work efficiency.

[Submission date] May 20, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content] [Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a tabletop cutting machine using an elastic endless belt as a power transmission means of a motor.

[0002]

[Prior art]

Conventionally, rotational control of the motor is disclosed, for example, in JP-A-61-180593. This is because, in a motor that performs forward and reverse rotations, a rotation speed and load current are detected, a motor rotation speed is kept constant, and a motor load current adjustment device is provided so that the rotation speed can be adjusted to a constant value. It was done. Oite here, but is to utilize a processing machine such as a drill, this control was the rotation control of the motors to be limited only to the load of processing. Further, it is well known that an endless belt is used as a power transmission means of a motor. However, there is no one that simultaneously controls the motor torque and rotation speed corresponding to the allowable transmission torque of the endless belt.

[0003]

[Problems to be solved by the device]

In the conventional motor control, in a tabletop cutting machine that uses an elastic endless belt as a power transmission means, the transmission torque of the endless belt is usually limited. Slip occurs between the blade shaft and the endless belt. In particular, slips frequently occurred when the motor was started, suddenly stopped, and overloaded, leading to early wear of the endless belt. Also, in the tabletop cutting machine, when the power supply to the motor is cut off, a brake device is provided to prevent inertial rotation of the cutting blade , and the motor is stopped suddenly. Performing Repeat this sudden stop, it had led to significant premature wear of the endless belt. In addition, in a tabletop cutting machine, the rotational speed of the cutting blade axis changes according to the actual load during cutting, which causes a difference in the cutting amount due to the fluctuation of the rotational speed on the cutting surface, resulting in the commonly known saw mark. However, the finish of the cut surface was deteriorated. Therefore, the operator must take place by holding back Gently the descent of the cutting blade portion such that the rotational speed of the cutting blade shaft does not change abruptly, had poor workability and work efficiency. The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to prevent the endless belt from slipping, to improve the finishing quality of the cut surface of the material to be cut, and to improve workability and work efficiency during cutting. To improve.

[0004]

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the tabletop cutting machine of the present invention is as follows. An elastic endless belt is used as the power transmission means of the tabletop cutting machine, and a rotation speed detection means for detecting the rotation speed of either the motor or the rotation drive section and a load current detection means for detecting the load current of the motor. The motor control means for controlling the rotation speed and the torque by performing a soft start for temporarily increasing the electric power supplied to the motor in response to the signals from the rotation speed detection means and the load current detection means. provided, is La, provided brake means for stopping the rotation of the motor at a time that does not generate slip between the motor shaft and an endless belt or between the cutting tool axis and the endless belts at the time of power cut off of the motor to the motors, the motor This is to control the rotation speed and torque in a related manner.

[0005]

[Action]

With the above configuration, when the motor is started, the motor control means starts the motor softly to start up the rotation of the motor gently and does not slip between the motor shaft and the endless belt or between the cutting blade shaft and the endless belt. Power is transmitted to the motor control means, and then the signal from the rotation speed detection means is fed back to the motor control means until the rotation speed of the motor is preset to the motor control means, and the motor rotation speed is controlled by the motor control means. To do. At this time, that is, the rotation speed preset as the no-load rotation speed is set to the same level as the actual load rotation speed of the material to be cut. Therefore, when the material to be cut is cut, the rotation speed of the cutting blade does not change, so that saw marks do not occur and the finishing quality of the cut surface can be improved . Further, since the load current is detected by the load current detection means of the motor, when the motor load detects a load that exceeds the allowable transfer torque of the endless belt while cutting the material to be cut, the motor control means It limits the input current and reduces the torque of the motor. This can prevent the endless belt from slipping during the cutting of the material to be cut. Further, when the power is cut off while the motor is rotating, the motor braking is stopped by the braking means of the motor when the slip does not occur between the motor shaft and the endless belt or between the cutting blade shaft and the endless belt. As a result, the endless belt does not slip and the inertial rotation of the motor can be stopped.

[0006]

【Example】

 An embodiment according to the present invention will be described with reference to FIGS. 1 is a left side view showing an embodiment of a tabletop cutting machine according to the present invention, FIG. 2 is a partial sectional front view of FIG. 1, and FIG.ofFIG. 4 is a partially enlarged sectional view, FIG. 4 is a block circuit diagram, and FIG. 5 is a motor rotation speed-torque, rotation speed-load current characteristic diagram. In the figure,Behind the upper surface of the base 1While fixing the fence 3 that supports the material 16 to be cut,A turntable 2 which is rotatable in the horizontal direction at approximately the center of the base 1. To bury. Behind the turntable 2, the holder shaft 4 can be tilted left and right around the holder shaft 4 as a fulcrum.A long hole (not shown) that supports the shaft and forms the clamp lever 5 on the holder 6 Of the holder 6 by fitting it into the screw hole formed at the rear of the turntable 2. The tilt position can be fixed. Above the holder 6, a cutting blade portion 8 provided with a cutting handle 14 is pivotally supported about a shaft 7 as a fulcrum so as to be vertically swingable with respect to the upper surface of the base 1.The cutting blade unit 8 includes a cutting blade 10, a motor 11 and a moving blade. It is composed of a motor housing 15 which houses force transmission means. With cutting blade 10 The power transmission means between the motors 11 includes the cutting blade shaft 9, the motor shaft 12, and the cutting blade shaft 9. An elastic endless belt 13 stretched between the motor shafts 12 is formed. Motor 11Is the motor shaft 12 on the opposite side of the endless belt 13.At the end ofA magnet ring 17 rotating with the motor shaft 12 is provided on a magnet holder 18 fixed to the motor shaft 12. The magnet ring 17 has a plurality of magnetic poles. On the magnet ring 17 side of the motor housing 15,Motor 11A controller box 19 serving as a motor controller means for controlling the motor is provided, and a magnetic pickup 20 serving as a rotational speed detecting means for detecting a magnetic pole of the magnet ring 17 is provided in the controller box 19.Motor 11Is generally called a series-wound commutator motor. An armature 22 is connected in series with the field winding 21, and a triac 23 for controlling the current flowing through the field winding 21 and the armature 22 and a load current. A resistor 24 serving as a detecting means is connected and housed in the controller box 19. Further, the power-generating braking coil 25, which serves as a braking means, is powered by a switch 26.ToIt is provided so as to form a closed circuit in series with the armature 22 and the field winding 21a when cut off. The dynamic braking coil 25 includes a field coil 27 that generates a field in a direction in which the armature 22 is braked.,A field coil 28 that generates a field in the direction opposite to the braking direction is connected and formed in series. The output signals of the magnet pickup 20 and the resistor 24 are connected to the control circuit 29 in the controller box 19, and the output signal of the control circuit 29 is connected to the gate of the triac 23 to control the triac 23. The control circuit 29 includes a circuit for gradually increasing the conduction angle of the triac 23 when the power is turned on, or data and the rotation speed N of the actual disconnection load.Endless belt 13 The torque value T of the allowable transmission torque of or the load current value I corresponding to this torque T is set. A current gradually flows through the armature 22 by the triac 23, and the rotation of the motor shaft 12 is temporarily increased to be a soft start. The power of the motor shaft 12 rotates the cutting blade 10 via the endless belt 13 and the cutting blade shaft 9. When the motor shaft 12 rotates, the magnet ring 17 rotates, and the magnet pickup 20 detects the rotation of the magnet ring 17 and outputs a signal to the control circuit 29. The control circuit 29PresetThe rotation speed N and the rotation speed from the magnet pick-up 20 are compared, and the triac 23 is controlled by the armature 22 so as to match the rotation speed of the set actual cutting load and prevent overshoot and ringing of the rotation speed. By controlling the flowing currentMotor 11Control the rotation of. Thereby, the rotation of the cutting blade 10 is controlled. The characteristics of the motor 11 of this embodiment are shown in FIG. In FIG.Broken lineIs the motor characteristic when control is not performed, and the solid line is the motor characteristic when control is performed.Limit the actual cutting load to the number of revolutions N and set the torque to the allowable transmission torque. The torque value T is regulated. The handle 14 lowers the cutting blade portion 8 and the cutting blade 10 cuts the workpiece 16. When the motor 11 The load current of,The load current is detected by detecting the voltage generated by the current flowing through the resistor 24 and inputting it to the control circuit 29. In addition, in the embodiment, the increase / decrease in the load current due to the characteristics of FIG.Of the motor shaft 12 torque Proportional to. By detecting the load current by this, indirectlyMo Torque of data shaft 12 Can be detected. Therefore, the control circuit 29 supplies the motor load current at the time of disconnection via the resistor 24,Torque of motor shaft 12The allowable transmission torque of the endless belt 13 is compared with the torque value T of the allowable transmission torque of the endless belt 13 which is set in advance.TThe triac 23 is controlled so as not to exceed.further, By switch 26Of the motor 11When the power is cut off, the armature 22 and the dynamic braking coil 25 become a closed circuit, and the kinetic energy of the armature 22 is reduced.soA field coil 27 that generates a voltage and a current flows through the dynamic braking coil 25 to brake the armature 22.,The rotation of the armature 22 is gently braked by the field coil 28 opposite to the direction in which the braking is applied, and the electric motor is operated in a time period during which no slip occurs between the motor shaft 12 and the endless belt 13 or between the cutting blade shaft 9 and the endless belt 13. The rotation of the child 22 stops, the rotation of the motor shaft 12 stops, and the rotation of the cutting blade shaft 9 stops via the endless belt 13.According to this embodiment,Since the handle 14 is provided at the extension of the cutting blade portion 8,Motor 11It is transmitted to the steering wheel 14 by soft start at startupmotor 11 There is no recoil at the time of startup and there is an effect of low noise. Further, since the distance between the motor shaft 12 and the cutting blade shaft 9 is increased by the endless belt 13, there is an advantage that a large tilt angle can be obtained when the holder 6 is tilted left and right.In this embodiment, the endless belt 13Is an elastic body, but it is a V-belt, poly-V-belt, etc. Or A steel belt such as an iron belt may be used. Rotational speed detection meansAs real The example is Although it is performed by the magnet ring 17 and the magnet pickup 20, a rotation detector such as a rotary encoder may be used. Further, the rotation speed detection means is the motor shaft 12ofThe rotations of the cutting blade shaft 9, the endless belt 13 and the like may be detected in addition to the ends. The control circuit 29 may be configured by a microcomputer, a phase control IC, or the like. The motor 11 is a series-wound commutator motor, but it is an induction motor.ButI do not care.In this embodiment,A braking coil 25 for power generation is formed in the braking means by a field coil 27 for generating a field in the braking direction and a field coil 28 for generating a field in the direction opposite to the braking direction to perform a gentle stop. However, the resistance value of the coil 25 for dynamic braking is simply increased to weaken the braking field, and the tension of the belt is used on the motor shaft 12 and the cutting blade shaft 9 to mechanically and gently brake. I don't mind. The rotation speed N and the torque value T preset in the control circuit 29 are determined by the motor characteristics., High efficiency point orYou may set it to a point with high cutting efficiency. As the triac 23 for controlling the motor current, a thyristor, FET, transistor, inverter control, etc. may be used.

[0007]

[Effect of device]

According to the present invention, the entire process from the time the motor starts up when the motor stops, since the control of the rotational speed and torque of the motor, and between the motor shaft and an endless belt between the cutting tool axis and the endless belt, slip proper torque does not occur, e setting speed row, it is possible to prolong the life of the endless belt. In addition, since the rotation speed feedback control is performed so that the rotation speed during cutting does not change suddenly, there is no difference in the cutting amount due to fluctuations in the rotation speed. It is possible to improve workability and work efficiency.

[Brief description of drawings]

FIG. 1 is a left side view showing an embodiment of a tabletop cutting machine according to the present invention.

FIG. 2 is a partial sectional front view of FIG.

FIG. 3 is an enlarged view of a partial cross section of FIG.

FIG. 4 is a block circuit diagram.

FIG. 5 is a characteristic diagram of motor rotation speed-torque and rotation speed-load current.

[Explanation of symbols]

8 is a cutting knife part, 9 is a cutting knife axis, 10 is a cutting knife, 1
1 is a motor part, 12 is a motor shaft, 13 is an endless belt, 1
6 is a material to be cut, 19 is a controller box, 20 is a magnetic pickup, 23 is a triac, 24 is a resistor, 25 is a coil for dynamic braking, 26 is a switch, 29
Is a control circuit.

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[Procedure amendment]

[Submission date] May 20, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Name of device] Desktop cutting machine

[Scope of utility model registration request]

[Brief description of drawings]

FIG. 1 is a left side view showing an embodiment of a tabletop cutting machine according to the present invention.

FIG. 2 is a partial sectional front view of FIG.

FIG. 3 is an enlarged view of a partial cross section of FIG.

FIG. 4 is a block circuit diagram.

FIG. 5 is a characteristic diagram of motor rotation speed-torque and rotation speed-load current.

[Explanation of Codes] 8 is a cutting blade, 9 is a cutting blade axis, 10 is a cutting blade, 1
1 is a motor, 12 is a motor shaft, 13 is an endless belt, 16
Is a material to be cut, 19 is a controller box, 20 is a magnetic pickup, 23 is a triac, 24 is a resistor, 25 is a coil for dynamic braking, 26 is a switch, and 29 is a control circuit.

Claims (4)

[Scope of utility model registration request] 1. A base for supporting a material to be cut, a turntable embedded in the base so as to be horizontally rotatable, a holder supported by a tilting member provided at the rear of the turntable so as to be tilted left and right, and an upper end of the holder. From a motor shaft having a cutting blade portion that supports a cutting blade shaft that is pivotally movable up and down with respect to the upper surface of the base with a provided shaft as a fulcrum, and a motor portion that is covered by a motor housing. In a tabletop cutting machine that rotates a cutting blade shaft through a power transmission means, an endless belt is used as the power transmission means, and a rotation speed detection means for detecting the rotation speed of either the motor or the rotation drive unit and the motor. A load current detecting means is provided to receive signals from the rotation speed detecting means and the load current detecting means to temporarily increase the electric power supplied to the motor and to allow the endless belt to operate. The motor control means is set in advance so as to regulate the proper number of rotations and the torque in relation to the transmission torque, and further, the motor is disconnected between the motor shaft and the endless belt when the power of the motor is cut off. A tabletop cutting machine characterized in that the motor is provided with a braking means for stopping the rotation of the motor during a time period during which no slip occurs between the blade shaft and the endless belt. 2. The tabletop cutting machine according to claim 1, wherein the endless belt is formed of an elastic body that absorbs electromagnetic vibrations of the motor and has a width parallel to the motor shaft. 3. The motor control means sets and controls the load rotation speed and the non-load rotation speed at the time of cutting the material to be cut to the same degree, and sets an appropriate delay time with respect to the load fluctuation. The tabletop cutting machine according to claim 1, wherein the tabletop cutting machine is provided and regulates overshoot and ringing of the load rotation speed to perform stable feedback control. 4. A serially wound commutator motor is used as the motor,
A coil for dynamic braking formed by a coil for generating a field for braking the rotation of the motor in a dynamic braking circuit of the series-wound commutator motor and a coil for applying a field in a direction opposite to the field for braking. The tabletop cutting machine according to claim 1, further comprising braking means.