JP3907950B2 - Electric tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a portable electric tool of hand-held and tabletop circular saw type such as a hammer drill, and more particularly to an electric tool provided with an illumination light and a warning light such as overheating.
[0002]
[Prior art]
As a conventional electric tool with a lighting device, US Pat. No. 2,525,588 proposes a lamp in which a lamp bulb and a lens glass are provided on a front cap of a casing to illuminate the tip of a drill. Japanese Utility Model Publication No. 49-54733 discloses a warning lamp for overheating of a small electric tool, in which a thermistor is attached to the field of a motor so that a neon tube is lit when overheated.
[0003]
[Problems to be solved by the invention]
In an electric tool, it is preferable that both a lighting device for a work location and a warning device for overheating coexist. However, the conventional power tool includes only one of them, and does not include both. It is because it is not preferable in terms of design because it takes up a place on the electric tool if both the lighting device and the alarm device are provided, and both the wiring is troublesome and the cost is increased. The present invention has been made to solve the above-described problems, and an object of the present invention is to enable simultaneous illumination and warning display of a work site using a single illuminator.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 of the present invention is a power tool provided with an illuminator that irradiates the vicinity of the tip of the tool, and a normal illumination driving means for normally lighting the illuminator; comprising an abnormality detecting device for detecting a motor abnormality, and a warning display drive means for different abnormal lighting display the normal illumination to the illuminator when the abnormality detecting device detects an abnormality,
The abnormality detection element is one or more of a temperature detection element that detects the temperature of the motor, a brush wear detection element that detects wear of the brush of the motor, and an overcurrent detection element that detects overcurrent of the motor. ,
The illuminator comprises three types of light emitting diodes (LEDs) consisting of red, green and blue,
The normal illumination driving means is means for causing the three types of light emitting diodes to emit light simultaneously,
The warning display driving means is means for turning off or blinking at least one of the three types of light emitting diodes according to the type of abnormality detected .
[0005]
When formed in this way, the illuminator is turned on by the normal illumination driving means at the normal time, and the worker can work safely. When the motor is abnormal, the warning display means displays an abnormal lighting such as blinking of the illuminator, so that the operator can easily know the abnormality of the motor and can interrupt the work. Since the illuminator also serves as a warning light, it is only necessary to attach one illuminating light to the power tool, the wiring is easy, and the design process is easy.
[0006]
In this case, as in the first aspect of the invention, the abnormality detection element includes a temperature detection element that detects the temperature of the motor, a brush wear detection element that detects wear of the brush of the motor, and an excessive current that detects an overcurrent of the motor. Any one or a plurality of current detection elements may be provided. When formed in this way, the illuminator displays abnormal illumination when the motor is overheated, and the illuminator displays abnormal illumination when the motor brush is consumed, depending on the type of anomaly detection element attached. Since the device displays abnormal illumination, the operator can easily know overheating of the motor, wear of the brush or overload of the motor according to the type of the abnormality detecting element attached.
[0007]
Here, as in the invention of claim 1, wherein the illuminator consists of red, green, and consisting of a blue three light emitting diode (LED), a said normal illumination driving unit, the three kinds of light-emitting diodes The warning display drive means is means for turning off or blinking at least one of the three types of light emitting diodes according to the type of abnormality detected. Can do.
[0008]
When formed in this manner, three types of light emitting diodes emit light simultaneously at the normal time. Since the three types of light emitting diodes have three primary colors of red, green, and blue, the three colors are mixed and white illumination light irradiates near the tip of the tool. When an abnormality occurs, such as when the motor is overheated, the color of the irradiation light changes or blinks to warn the operator of the abnormality. For example, when an overload occurs due to overcurrent, the green and blue light emitting diodes are turned off and only the red light emitting diodes are turned on, resulting in red illumination. Become a signal. Furthermore, when the brush is worn, if only the green light-emitting diode is turned on, the illumination becomes green. In this case as well, the electric tool only needs to be provided with one set of light emitting diodes at the same place, so that the wiring is easy and the design process is easy.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of a power tool according to the present invention, with a part of a handle portion cut away. An electric motor is accommodated in the main body 12 of the electric tool 11, and a chuck 13 that holds the tool 14 is provided at the tip. The handle portion 15 of the electric tool 11 is provided with a trigger switch 16 that activates the electric motor. Below the trigger switch 16, an RGB-LED light-emitting diode 17 comprising a set of three types of light-emitting diodes of red, green and blue is disposed so as to irradiate the vicinity of the tip of the tool 4 as indicated by a chain line 18. Has been. The RGB-LED light emitting diode 17 constitutes an illuminator.
[0010]
FIG. 2 is a block diagram showing an embodiment of the control device for the electric tool. The electric motor 20 includes an armature 21, two field windings 22 and 23, and brushes 24 and 25. The electric motor 20 is connected to a power source by a trigger switch 16. In addition, a shunt resistor 26 is connected in series to the electric motor 20 so that a load current flowing through the electric motor 20 can be detected. The shunt resistor 26 serves as an overcurrent detection element. The field winding 23 is provided with a thermistor 27 that is a temperature detection element for detecting the temperature of the electric motor 20. Further, the brush 24 is provided with a brush wear detecting element 28. Signals from the shunt resistor 26, the thermistor 27, and the brush wear detecting element 28 are input to a microcomputer 30 as a control unit.
[0011]
Further, the microcomputer 30 receives a signal from the illumination switch 31 that turns on and off the illumination function. In this embodiment, the illumination switch 31 is interlocked with the trigger switch 16, and the illumination switch 31 is also turned on when the trigger switch 16 is pulled. The output of the microcomputer 30 is connected to an illuminator drive circuit 40, and the illuminator drive circuit 40 drives an RGB-LED light emitting diode 17 composed of a set of three types of light emitting diodes which are illumination warning combined lights.
[0012]
FIG. 3 is a cross-sectional view showing the structure of the brush wear detecting element 28. The brush 24 mainly composed of graphite is held by a brush tube 101 made of a conductor and a brush holder 102 made of an insulator, and is pressed and urged by a compression spring 103. A small hole is formed in the side surface of the brush tube 101 and the brush holder 102, and a stepped columnar probe 105 is accommodated in the small hole. The probe 105 is made of an insulator, and its tip is in sliding contact with the side surface of the brush 24. The back surface (from the right side of the drawing) of the probe 105 is pressed by the leaf spring 106 so that the tip of the probe 105 comes into contact with the side surface of the brush 24. When the brush 24 wears and falls below the position of the probe 105, the tip of the probe 105 is disengaged from the side surface of the brush 24, the probe 105 advances, and the leaf spring 106 contacts the contact 107 to detect the wear of the brush 24. . The probe 105, the leaf spring 106, and the contact 107 constitute a brush wear detection element 28.
[0013]
FIG. 4 is a circuit diagram showing a control device for an AC power tool. A constant voltage current is supplied from an AC power source 51 such as a commercial power source to the microcomputer 30 by a constant voltage circuit including a diode D1, a resistor R1, a capacitor C1, and a Zener diode ZD1. Similarly, a constant voltage current is supplied from an AC power source 51 such as a commercial power source to the illuminator drive circuit 40 by a constant voltage circuit including a diode D2, a resistor R2, a capacitor C2, and a Zener diode ZD2.
[0014]
The input system of the microcomputer 30 will be described. The illumination switch 31 has one end connected to the common line 202 and the other end connected to the power supply line 201 by a pull-up resistor and is input to the microcomputer 30 via the input resistor. The detection voltage of the shunt resistor 26 that detects the load current of the armature 21 is input to the microcomputer 30 via the input resistance. One end of the thermistor 27 is connected to the common line 202, and the other end is connected to the power supply line 201 by a pull-up resistor and to the microcomputer 30. The signal of the brush wear detecting element 28, which is a contact signal, has one contact connected to the common line 202, the other contact connected to the power supply line 201 by a pull-up resistor, and the microcomputer 30 via the input resistor. It is connected to the.
[0015]
The output system of the microcomputer 30 and the illuminator drive circuit 40 will be described. The RBG-LED light emitting diode 17 driven by the illuminator driving circuit 40 includes four light emitting diodes. One red light-emitting diode R, green light-emitting diode G, and two blue light-emitting diodes B. The microcomputer 30 uses four output terminals, and each output terminal is connected to the base of each drive transistor 41, 42, 43, 44 via a base resistor. The emitters of the drive transistors 41, 42, 43, and 44 are connected to the common line 202, and the collectors are connected to the bases of the PNP type switching transistors 45, 46, 47, and 48 via base resistors, respectively, and pulled up. The power supply line 203 is connected via a resistor.
[0016]
The emitters of the switching transistors 45, 46, 47, and 48 are connected to the power supply line 203, and the collectors are respectively connected to the red LED R, the blue LED B, and the green LED of the RGB-LED LED 17 via current limiting resistors. G, connected to the anode of the blue light emitting diode B. The cathodes of the respective light emitting diodes R, B, G, B are connected to the common line 202. Therefore, when each output terminal of the microcomputer 30 becomes H, the corresponding switching transistors 45, 46, 47, and 48 are turned on, and the RGB-LED light emitting diodes 17 emit red, blue, green, and blue.
[0017]
FIG. 5 is a circuit diagram showing a control device for a DC power tool. Since the power tool is different from the AC power tool described with reference to FIG. 4 and the others are the same, the same members are denoted by the same reference numerals and description thereof is omitted. A DC power source 52 such as a battery is connected to the armature 21 of the electric motor 20 via the trigger switch 16. Since the electric motor 20 uses a permanent magnet field, there are no field windings 22 and 23. From the DC power source 52, the voltage is dropped by a constant voltage circuit including a resistor R 1, a capacitor C 1, and a Zener diode ZD 1 to form a power line 201, and a constant voltage current is supplied to the microcomputer 30. The detection elements 26, 27, and 28 and the illumination switch 31 that are input to the microcomputer 30 are the same as those described with reference to FIG. The power supply line 204 from the DC power supply 52 is directly led to the illuminator drive circuit 40. The illuminator drive circuit 40 is the same as that described in FIG. Therefore, when each output terminal of the microcomputer 30 becomes H, the corresponding switching transistors 45, 46, 47, and 48 are turned on, and the RGB-LED light emitting diodes 17 emit red, blue, green, and blue.
[0018]
FIG. 6 is a flowchart showing processing in the microcomputer 30. When power is turned on to the power tool 11, the processing of the microcomputer 30 is started (S10). First, the microcomputer 30 is initialized (S11). Subsequently, the temperature signal T from the thermistor 27 is read (S12). Then, it is determined whether or not the temperature signal T is equal to or greater than a predetermined value T0 (for example, 80 ° C.) (S13). If the temperature signal T is equal to or greater than the predetermined value T0, the process proceeds to S14 and an overtemperature warning signal is output. As the overtemperature warning signal, for example, only the drive transistor 41 is intermittently turned on / off, and only the red light emitting diode R of the RGB-LED light emitting diodes 17 is blinked. Then, the process returns from S14 to S12.
[0019]
If the temperature signal T is less than or equal to the predetermined value T0, the process proceeds from S13 to S16. In S16, the contact signal from the brush wear detecting element 28 is read. In S17, it is determined whether or not the contact is closed, that is, whether or not the brush is worn and shortened. If the brush is worn, the process proceeds to S18 and a brush wear warning signal is output. As the brush wear warning signal, for example, only the driving transistor 43 is intermittently turned on and off, and only the green light emitting diode G of the RGB-LED light emitting diodes 17 is blinked. Then, the process returns from S18 to S12.
[0020]
If the brush is not worn, the process proceeds from S17 to S20. In S20, the load current value from the shunt resistor 26 is read. In S21, it is determined whether or not the load current is an overcurrent. If the load current is an overcurrent, the process proceeds to S22 and an overcurrent warning signal is output. As the overcurrent warning signal, for example, only the drive transistors 42 and 44 are intermittently turned on and off, and only the blue light-emitting diode B of the RGB-LED light-emitting diodes 17 is blinked. Then, the process returns from S22 to S12.
[0021]
If the load current is not an overcurrent, the process proceeds from S21 to S24. In S24, the contact signal from the illumination switch 31 is read. In S24, it is determined whether or not the illumination switch 31 is closed. If the illumination switch 31 is closed, the process proceeds to S26 and the illumination operation is output. As an illumination operation output, all the four drive transistors 41, 42, 43, and 44 are turned on, and all the light emitting diodes RBG of the RGB-LED light emitting diodes 17 are turned on. As a result, light of three colors of red, green, and blue is mixed and becomes white light to illuminate the vicinity of the tool. Then, the process returns from S26 to S12.
[0022]
If the illumination switch 31 is open, nothing is executed and the process returns from S25 to S12. What is noticed here is that warning signals from the thermistor 27, the brush wear detecting element 28, and the shunt resistor 26 are read in preference to the lighting switch 31. Therefore, only when there is no warning signal, the illumination switch 31 is activated and illumination is performed. When any warning signal is output, the warning signal is given priority.
[0023]
In the above configuration, the processes of S25 and S26 constitute normal illumination driving means, and the processes of S13, S14 and S17, S18 and S21, S22 constitute warning display driving means.
[0024]
Based on the above configuration, the operation will be described. When the electric power tool 11 is connected to the power source, normally, no warning signal is issued unless the brush 24 is worn. When the trigger switch 16 is pulled, the electric motor 20 is driven to rotate, and the RGB-LED light emitting diode 17 emits white light. Light is irradiated to illuminate the work place and improve work efficiency. If an overload (overcurrent) is detected during the work, the white illumination is extinguished and the blue light blinks. Therefore, it is sufficient to weaken the force for pressing the electric tool 11 against the work location. If green light blinks during work or at the start of work, the brushes 24 and 25 are worn, so the brushes 24 and 25 are replaced. If the red light blinks during the work, the motor 20 is overheated, so the work may be interrupted and stopped.
[0025]
In this embodiment, the RGB-LED light-emitting diode 17 as an illuminator is attached not to the main body 12 in which the electric motor 20 is accommodated but to the handle portion 15 having a relatively large margin, so that the assembly is easy and the wiring is routed. Will also be easier.
[0026]
In the embodiment described above, in order to simplify the description, one type of light emitting diode blinks according to the type of abnormality, but in reality, a color that is perfect for human sensitivity according to the type of abnormality. It is easy to blink or irradiate the light. The color change can be realized by appropriately selecting a duty ratio that causes the light emitting diodes of the three primary colors red, green, and blue to blink at an extremely short time interval.
Further, it will be apparent to those skilled in the art from the present invention that a warning may be displayed by using a light bulb without using a light emitting diode, continuously lighting in a normal state, and blinking in an abnormal state.
In the above embodiment, the illumination switch 31 is interlocked by the trigger switch 16. However, the illumination switch 31 may be provided separately from the trigger switch 16.
[0027]
【The invention's effect】
As described above, since the present invention includes an illuminator and warns of an abnormal state by the illuminator, the work efficiency can be improved by the illumination, and further, an excellent effect that an abnormal state can be quickly treated. There is. And since the warning display is performed using the illuminator, the wiring can be reduced as compared with the case where the warning indicator lamp is provided separately, and there is an effect that the assembling property is improved and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a side view of an electric power tool according to the present invention, with a handle portion partially broken away.
FIG. 2 is a block diagram showing a control device for an electric tool.
FIG. 3 is a cross-sectional view showing the structure of a brush wear detecting element.
FIG. 4 is a circuit diagram showing a control device for an AC power tool.
FIG. 5 is a circuit diagram showing a control device for a direct-current power tool.
FIG. 6 is a flowchart showing processing in a microcomputer.
[Explanation of symbols]
11 Electric tool 16 Trigger switch 17 RBG-LED light emitting diode (illuminator)
26 Shunt resistor (overcurrent detection element)
27 Thermistor (Temperature detection element)
28 Brush Wear Detection Element 30 Microcomputer

Claims (1)

In an electric tool equipped with an illuminator that illuminates the vicinity of the tip of the tool,
Normal illumination driving means for normally lighting the illuminator;
An abnormality detecting element for detecting an abnormality of the electric motor;
A warning display driving means for the abnormal lighting display that is different from the normal illumination to the illuminator when the abnormality detecting device detects an abnormality,
Equipped with a,
The abnormality detection element is one or more of a temperature detection element that detects the temperature of the motor, a brush wear detection element that detects wear of the brush of the motor, and an overcurrent detection element that detects overcurrent of the motor. ,
The illuminator comprises three types of light emitting diodes (LEDs) consisting of red, green and blue,
The normal illumination driving means is means for causing the three types of light emitting diodes to emit light simultaneously,
The warning display driving means is means for turning off or blinking at least one of the three types of light emitting diodes according to the type of abnormality detected.
An electric tool characterized by that.

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