CN110855189A - Accidental start prevention circuit of electric tool controller - Google Patents

Accidental start prevention circuit of electric tool controller Download PDF

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Publication number
CN110855189A
CN110855189A CN201911145815.8A CN201911145815A CN110855189A CN 110855189 A CN110855189 A CN 110855189A CN 201911145815 A CN201911145815 A CN 201911145815A CN 110855189 A CN110855189 A CN 110855189A
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CN
China
Prior art keywords
resistor
electric tool
capacitor
transistor
switch
Prior art date
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Pending
Application number
CN201911145815.8A
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Chinese (zh)
Inventor
刘庆江
于盛
李军建
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhangjiagang Huajie Electronics Co Ltd
Black and Decker Inc
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Black and Decker Inc
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Filing date
Publication date
Application filed by Black and Decker Inc filed Critical Black and Decker Inc
Priority to CN201911145815.8A priority Critical patent/CN110855189A/en
Publication of CN110855189A publication Critical patent/CN110855189A/en
Pending legal-status Critical Current

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02PCONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P1/00Arrangements for starting electric motors or dynamo-electric converters
    • H02P1/02Details of starting control
    • H02P1/022Security devices, e.g. correct phase sequencing

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  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Power Engineering (AREA)
  • Secondary Cells (AREA)

Abstract

The invention relates to an accidental start preventing circuit of an electric tool controller, which comprises a first resistor and a capacitor, wherein the first resistor and the capacitor are connected in series on a B + terminal of an electric tool battery pack, the first resistor is positioned between the B + terminal and the capacitor, the other end of the capacitor is grounded, and the first resistor and the capacitor are electrically connected with a single chip microcomputer through a switch. The invention utilizes the single chip microcomputer to detect the voltage of the capacitor connected to the terminal B + of the battery pack, judges whether the starting of the electric tool belongs to normal starting or accidental starting according to the voltage change curve, and controls the action of the motor according to the judgment result, thereby ensuring that the motor does not work when the electric tool is accidentally started and normally runs when the electric tool is normally started, and effectively improving the use safety of the electric tool.

Description

Accidental start prevention circuit of electric tool controller
The technical field is as follows:
the invention relates to an accidental start preventing circuit of an electric tool controller.
Background art:
portable electric tool is more and more receiving user's favor because convenience, the flexibility of its use, but portable electric tool has a biggest drawback just to be the battery reserves restriction, and long in order to improve electric tool uses, can be equipped with two to three battery package for change for an electric tool usually, and when changing the battery, we discover, have a condition and can cause the injury to the user. Usually when the battery package electric quantity is not enough, the instrument can automatic shutdown, lead to the user to be difficult to judge whether the state of electric tool switch is the disconnection or the closure because electric tool loses the electricity this moment, if change the battery package then safe in the disconnection state, but if the switch directly changes the battery package in the closure state, then the electric tool that probably appears installing the battery package starts in the twinkling of an eye, because electric tool has great impact force, and some electric tool have the cutter, consequently, electric tool burst operation is very easy to hurt the user when installing the battery package.
The invention content is as follows:
the technical problem to be solved by the invention is as follows: the utility model provides an unexpected starting circuit of preventing of electric tool controller, this circuit plays a role in electric tool switch closed state installation battery package, restriction motor work to avoid the unexpected start-up of motor to cause the injury to the user.
In order to solve the technical problems, the invention adopts the technical scheme that: the accidental starting prevention circuit of the electric tool controller comprises a first resistor and a capacitor which are connected in series on a B + terminal of an electric tool battery pack, wherein the first resistor is located between the B + terminal and the capacitor, the other end of the capacitor is grounded, and the first resistor and the capacitor are electrically connected with a single chip microcomputer through a switch.
As a preferred scheme, a second resistor is further connected in series between the switch and the single chip microcomputer.
As a preferred scheme, a third resistor is connected in parallel between the second resistor and the singlechip, the other end of the third resistor is grounded, and the resistance value of the third resistor is smaller than that of the first resistor.
As a preferable scheme, the switch includes a first triode and a second triode which are connected in series, wherein the first triode is a PNP triode, the second triode is an NPN triode, an emitter of the first triode is connected between the first resistor and the capacitor, a collector of the first triode is connected with the second resistor, a base of the first triode is communicated with a collector of the second triode, a base of the second triode is connected to the control switch of the electric tool, and the emitter of the second triode is grounded.
The invention has the beneficial effects that: the invention utilizes the single chip microcomputer to detect the capacitance voltage variation trend when the electric tool is switched on and switched off, judges the electric tool to be started accidentally or normally according to the capacitance voltage variation trend, controls the motor according to the judgment result, limits the motor to work when the judgment result is the accidental start so as to ensure the personal safety of a user, and controls the motor to work when the judgment result is the normal start so as to ensure the normal use of the electric tool.
The invention further connects a second resistor between the switch and the singlechip to limit the current in the circuit, thereby avoiding the damage of the singlechip caused by overlarge current.
The invention further connects a third resistor in parallel between the second resistor and the single chip, and the other end of the third resistor is grounded, thereby reducing the voltage of the detection end of the single chip and further ensuring the use safety of the single chip.
The invention further uses the first triode and the second triode which are mutually connected in series as switches, thereby utilizing the control voltage to turn on or off the switches, and realizing the synchronous switching of the switch of the accidental starting prevention circuit and the switch of the electric tool.
Description of the drawings:
the following detailed description of embodiments of the invention is provided in conjunction with the appended drawings, in which:
FIG. 1 is an electrical schematic of the present invention;
FIG. 2 is a graph of the change in capacitor voltage detected by the single chip during normal start-up of the power tool;
fig. 3 is a graph of the change of the capacitor voltage detected by the single chip microcomputer when the electric tool is accidentally started due to the battery pack installed in the switch closed state.
In fig. 1: 1. the circuit comprises a first resistor, a second resistor, a capacitor, a third resistor, a switch, a first triode, a second triode, a third triode, a singlechip, a second resistor, a third resistor and a fourth resistor.
The specific implementation mode is as follows:
specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
As shown in fig. 1, the accidental start preventing circuit of the electric tool controller comprises a first resistor 1 and a capacitor 2 which are connected in series on a battery pack B + terminal of the electric tool, the first resistor 1 is positioned between the B + terminal and the capacitor 2, the other end of the capacitor 2 is grounded, the first resistor 1 and the capacitor 2 are electrically connected with a single chip microcomputer 4 through a switch 3, a second resistor 5 is connected in series between the switch 3 and the single chip microcomputer 4, a third resistor 6 is connected in parallel between the second resistor 5 and the single chip microcomputer 4, the other end of the third resistor 6 is grounded, and the resistance of the third resistor 6 is smaller than that of the first resistor 1.
The switch 3 comprises a first triode 301 and a second triode 302 which are mutually connected in series, wherein the first triode 301 is a PNP triode, the second triode 302 is an NPN triode, an emitting electrode of the first triode 301 is connected between a first resistor 1 and a capacitor 2, a collecting electrode is connected with a second resistor 5, a base electrode is communicated with a collecting electrode of the second triode 302, a base electrode of the second triode 302 is connected to a control switch of the electric tool, and the emitting electrode is grounded.
The working principle of the invention is as follows: as shown in fig. 1, when the battery pack is installed when the control switch of the power tool is turned off, B + is charged and charges the capacitor 2 through the first resistor 1 and is charged quickly while the battery pack is installed, which is about 2ms, so that it is impossible for an operator to close the control switch of the power tool in such a short time.
After the battery pack is installed, an operator closes a control switch of the electric tool, at the moment, the base electrode of the second triode 302 is electrified to form a high level, the collector electrode and the emitter electrode of the second triode 302 are enabled to be conducted, the base electrode of the first triode 301 is formed into a low level, the emitter electrode and the collector electrode of the first collector electrode 301 are further conducted, the switch 3 is conducted, the capacitor 2, the second resistor 5 and the third resistor 6 are conducted, the capacitor 2 starts to discharge, since the initial voltage of the capacitor 2 is higher, as the discharge time goes on and since the resistance of the third resistor 6 is smaller than that of the first resistor 1, therefore, the voltage detected by the single chip 4 is gradually reduced from the high voltage and then stabilized at a lower voltage value, forming a voltage trend chart as shown in fig. 2, under the condition, the singlechip 4 judges that the electric tool is normally started, and the singlechip 4 controls the motor to normally work.
When the control switch of the electric tool is closed to install the battery pack, B + is powered on and the base of the second triode 302 forms a high level to switch on the switch 3 when the battery pack is installed, at the moment, because the capacitor 2 is not powered yet, the terminal B + is still in a state of charging the capacitor 2, therefore, the voltage detected by the singlechip 4 is very low, along with continuous power supply of the battery pack, the voltage detected by the singlechip 4 gradually rises to a heightened level and then keeps balance, and a voltage trend graph as shown in figure 3 is formed, under the condition, the singlechip 4 judges that the electric tool is started accidentally, and the singlechip 4 controls the motor not to work.
How the single chip microcomputer 4 controls the motor to stop working or normally work can be realized through a relay connected with the motor driving circuit in series.
The above embodiments are merely illustrative of the principles and effects of the present invention, and some embodiments in use, and are not intended to limit the invention; it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the inventive concept of the present invention, and these changes and modifications belong to the protection scope of the present invention.

Claims (4)

1. The accidental starting prevention circuit of the electric tool controller is characterized by comprising a first resistor (1) and a capacitor (2) which are connected in series on a B + terminal of an electric tool battery pack, wherein the first resistor (1) is located between the B + terminal and the capacitor (2), the other end of the capacitor (2) is grounded, and the first resistor (1) and the capacitor (2) are electrically connected with a single chip microcomputer (4) through a switch (3).
2. The circuit for preventing accidental start of a controller of an electric tool according to claim 1, characterized in that a second resistor (5) is connected in series between the switch (3) and the single chip microcomputer (4).
3. The circuit for preventing the accidental start of the electric tool controller according to claim 2, wherein a third resistor (6) is connected in parallel between the second resistor (5) and the single chip microcomputer (4), the other end of the third resistor (6) is grounded, and the resistance value of the third resistor (6) is smaller than that of the first resistor (1).
4. The circuit of claim 1, wherein the switch (3) comprises a first transistor (301) and a second transistor (302) connected in series, wherein the first transistor (301) is a PNP transistor, the second transistor (302) is an NPN transistor, an emitter of the first transistor (301) is connected between the first resistor (1) and the capacitor (2), a collector of the first transistor is connected to the second resistor (5), a base of the first transistor is connected to a collector of the second transistor (302), a base of the second transistor (302) is connected to a control switch of the power tool, and an emitter of the second transistor is grounded.
CN201911145815.8A 2019-11-21 2019-11-21 Accidental start prevention circuit of electric tool controller Pending CN110855189A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911145815.8A CN110855189A (en) 2019-11-21 2019-11-21 Accidental start prevention circuit of electric tool controller

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911145815.8A CN110855189A (en) 2019-11-21 2019-11-21 Accidental start prevention circuit of electric tool controller

Publications (1)

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CN110855189A true CN110855189A (en) 2020-02-28

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022094851A1 (en) * 2020-11-05 2022-05-12 Techtronic Cordless Gp Power tool control system

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040155529A1 (en) * 2003-02-07 2004-08-12 Brotto Daniele C. Method and system for sensing switch position to prevent inadvertent startup of a motor
DE102010055626A1 (en) * 2010-12-22 2012-06-28 Continental Automotive Gmbh Circuit arrangement for detecting battery voltage produced by battery for e.g. starting engine of motor car, has voltage sensor detecting voltage on resistors that lie between end of series connections and electrical connection part
CN102723693A (en) * 2012-05-31 2012-10-10 南京德朔实业有限公司 Load protection circuit and method for electric tool
CN104779605A (en) * 2015-05-04 2015-07-15 苏州百微成智能科技有限公司 Power-off protection and control device
CN204538696U (en) * 2015-05-04 2015-08-05 苏州百微成智能科技有限公司 Power-off protection control device, power-off protection control circuit and electric tool
CN106385207A (en) * 2016-11-11 2017-02-08 江苏天行健汽车科技有限公司 DC brushless motor control system for preventing accidental starting
CN210807117U (en) * 2019-11-21 2020-06-19 张家港华捷电子有限公司 Accidental start prevention circuit of electric tool controller

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040155529A1 (en) * 2003-02-07 2004-08-12 Brotto Daniele C. Method and system for sensing switch position to prevent inadvertent startup of a motor
DE102010055626A1 (en) * 2010-12-22 2012-06-28 Continental Automotive Gmbh Circuit arrangement for detecting battery voltage produced by battery for e.g. starting engine of motor car, has voltage sensor detecting voltage on resistors that lie between end of series connections and electrical connection part
CN102723693A (en) * 2012-05-31 2012-10-10 南京德朔实业有限公司 Load protection circuit and method for electric tool
CN104779605A (en) * 2015-05-04 2015-07-15 苏州百微成智能科技有限公司 Power-off protection and control device
CN204538696U (en) * 2015-05-04 2015-08-05 苏州百微成智能科技有限公司 Power-off protection control device, power-off protection control circuit and electric tool
CN106385207A (en) * 2016-11-11 2017-02-08 江苏天行健汽车科技有限公司 DC brushless motor control system for preventing accidental starting
CN210807117U (en) * 2019-11-21 2020-06-19 张家港华捷电子有限公司 Accidental start prevention circuit of electric tool controller

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022094851A1 (en) * 2020-11-05 2022-05-12 Techtronic Cordless Gp Power tool control system

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