CN2225730Y - Moment limiter for electric tool - Google Patents
Moment limiter for electric tool Download PDFInfo
- Publication number
- CN2225730Y CN2225730Y CN 94239935 CN94239935U CN2225730Y CN 2225730 Y CN2225730 Y CN 2225730Y CN 94239935 CN94239935 CN 94239935 CN 94239935 U CN94239935 U CN 94239935U CN 2225730 Y CN2225730 Y CN 2225730Y
- Authority
- CN
- China
- Prior art keywords
- resistance
- relay
- electric tool
- moment
- thyristor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
The utility model relates to a moment limiter for an electric tool, which can judge the magnitude of the load moment by detecting the load current in the AC electric tool. When the load moment reaches the predetermined moment, the current taken by a sampling resistor which is rectified and filtered triggers a thyristor, a relay is attracted, the normally closed contact is off, and the circuit is switched off. The circuit can be switched off under the condition that the load moment of the tool is too big, or the tool is jammed, the operator of the electric tool and the electric tool are protected.
Description
The utility model is a kind of loading moment restricting circuits that is used for the AC electrical instrument, belongs to the electrical control gear in the electric tool.
Present domestic electric tool does not still use the moment limiting device of electrical control, though abroad have, complex circuit needs special-purpose integrated package, the TBH2RP electric hammer of producing as German BOSCH company.
The purpose of this utility model provides a kind of simple and reliable loading moment restraint device.
For achieving the above object, the technical solution adopted in the utility model is: a kind of electric tool limiter of moment, after connecting, the moving disconnecting point J1 of load and relay J and sampling resistor R1 be access to power supply, power supply is by diode D3, resistance R 5 be connected on the anode of thyristor G after relay J is connected, be parallel to sampling resistor R1 two ends after setting potentiometer W and resistance R 2 being connected, the potentiometer mid point extremely links to each other with the control of thyristor G by the series circuit of diode D1 and resistance R 3, resistance R 4, capacitor C 1, C2 all is parallel to the control utmost point and the negative electrode two ends of thyristor G, and filter capacitor C3 and sustained diode 2 all are parallel to the relay J two ends.
The time constant of the RC circuit of being made up of resistance R 3, resistance R 4, capacitor C 1 was more than or equal to 0.3 second.
Characteristics of the present utility model are that circuit is simple, and reliable operation can be used in some more powerful electric tools; as electric hammer etc.,, can protect the electric tool operator when work, not thrown or sprain to limit high capacity moment; especially when work high above the ground, can prevent that injury accident from taking place.This device can also use in some expensive electric tools, is not damaged with the protection electric tool.
Below in conjunction with accompanying drawing the utility model is described.
Among the figure: R1-R5 is a resistance; C1-C3 is an electric capacity; D1-D3 is a diode; G is a unidirectional thyristor; J is a relay line bag; J1 is the relay J break contact; J2 is the relay J make contact; W is a potentiometer; M is a circuit common.
As figure, after connecting electric tool and moving disconnecting point J1 of figure repeat circuit J and sampling resistor R1 connect, load L is access to power supply, and a certain power end that links with sampling resistor R1 is common port M.When loading moment increases, current of electric also increases, this electric current produces pressure drop on sampling resistor R1, this voltage obtains the pulsating semi-wave direct current after being sent to diode D1 rectification by the setting potentiometer W mid point in parallel with sampling resistor R1, pass through R3, directly remove to trigger the control utmost point of highly sensitive thyristor G after the C1 filtering, when loading moment reaches a certain set point, be that electric current reaches a certain set point, the thyristor G connection that is triggered, direct current relay J adhesive, moving disconnecting point J1 disconnection, the make contact J2 closure that links to each other with relay line bag lower end, the relay J self-insurance, circuit is cut off, and electric tool quits work.Form the relay current supply circuit after D3, R5, relay J are connected with thyristor G, wherein D3 carries out halfwave rectifier, and R5 is a dropping resistor.Because halfwave rectifier, the relay J contact will cause beats, so adopt capacitor C3 directly to be parallel to the relay J two ends, has reduced the rated voltage of capacitor C3, helps reducing cost and reducing volume.Wherein do not bear back-pressure, fly-wheel diode when yet being the relay J dead electricity simultaneously with relay J diode connected in parallel D2 protection capacitor C 3.
Resistance R 4 is parallel between thyristor G trigger electrode and negative electrode in the accompanying drawing, to reduce the input impedance of thyristor G, has improved the anti-interference ability of thyristor.Capacitor C 2 is that low capacity electric capacity is with filtering high frequency interference.
Because impulse current is very big during the electric tool electric motor starting, will cause the limiter of moment misoperation.The filter circuit that this practical firewood type is made up of R3, R4, C1 adopts time constant to reach more than 0.3 second.If resistance R 3 obtains greatly, circuit operation sensitivity reduces, so this circuit adopts the RC circuit of the big electric capacity of low resistance.The R2 that connects with potentiometer W defines maximum actuation moment.After the power supply dead electricity, relay J discharges, and relay J is moved disconnecting point J1 closure, and circuit recovers automatically.
Claims (2)
1. electric tool limiter of moment, it is characterized in that: be access to power supply after the moving disconnecting point J1 of load and relay J and sampling resistor R1 connect, power supply is by diode D3, resistance R 5 be connected on the anode of thyristor G after relay J is connected, be parallel to sampling resistor R1 two ends after setting potentiometer W and resistance R 2 being connected, the potentiometer mid point extremely links to each other with the control of thyristor G by the series circuit of diode D1 and resistance R 3, resistance R 4, capacitor C 1, C2 all is parallel to the control utmost point and the negative electrode two ends of thyristor G, and filter capacitor C3 and sustained diode 2 all are parallel to the relay J two ends.
2. limiter of moment according to claim 1 is characterized in that: the time constant of the RC circuit of being made up of resistance R 3, resistance R 4, capacitor C 1 was more than or equal to 0.3 second.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 94239935 CN2225730Y (en) | 1994-12-29 | 1994-12-29 | Moment limiter for electric tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 94239935 CN2225730Y (en) | 1994-12-29 | 1994-12-29 | Moment limiter for electric tool |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2225730Y true CN2225730Y (en) | 1996-04-24 |
Family
ID=33847042
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 94239935 Expired - Fee Related CN2225730Y (en) | 1994-12-29 | 1994-12-29 | Moment limiter for electric tool |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2225730Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100366399C (en) * | 2005-06-16 | 2008-02-06 | 朝程工业股份有限公司 | Electric tool torque controlling device |
| CN101051744B (en) * | 2006-04-07 | 2013-03-27 | 罗伯特·博世有限公司 | Electric machine tool and method for operating thereof |
| CN109599839A (en) * | 2019-01-14 | 2019-04-09 | 深圳和而泰智能控制股份有限公司 | A kind of protection circuit and blender |
-
1994
- 1994-12-29 CN CN 94239935 patent/CN2225730Y/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100366399C (en) * | 2005-06-16 | 2008-02-06 | 朝程工业股份有限公司 | Electric tool torque controlling device |
| CN101051744B (en) * | 2006-04-07 | 2013-03-27 | 罗伯特·博世有限公司 | Electric machine tool and method for operating thereof |
| CN109599839A (en) * | 2019-01-14 | 2019-04-09 | 深圳和而泰智能控制股份有限公司 | A kind of protection circuit and blender |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |