CN2096180U

CN2096180U - Safety protector for electric blanket

Info

Publication number: CN2096180U
Application number: CN 91217213
Authority: CN
Inventors: 张福来
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-07-04
Filing date: 1991-07-04
Publication date: 1992-02-12

Abstract

The utility model relates to an improved safety protector for an electric blanket, which is mainly composed of a main power supply, a direct current power supply, a sample circuit, an amplifying circuit, an output stage relay and a final control relay. The utility model is characterized in that the bridge type sample circuit is adopted to detect the impedance of an electric blanket. When the impedance is beyond the normal value, the power supply is cut off, thereby, the fire accidents generated by striking fire and overheating can be prevented effectively. The utility model is also provided with an over-voltage protection circuit and an under-voltage protection circuit. When the fluctuation of the electric network is beyond limit, the electric blanket can be protected.

Description

Safety protector for electric blanket

A kind of improved protector that is used for the electric blanket safe handling belongs to the electrical protective device technical field.

Electric blanket is sleep in a winter warming appliance commonly used.In the practical application, often because of the control switch loose contact, heating wire or its junction fracture sparking and cause fire, for this reason, have invented various protective devices, are used for detection and give newspaper hidden danger on fire.Wherein, comparatively practical is to utilize a temperature-sensing probe to detect the actual temperature of electric blanket, cuts off the electricity supply and gives the alarm when finding overtemperature.But this protector can only be in hidden danger greatly when enough making probe action, could detect to obtain.And in the fault starting stage, then can't find out.

The purpose of this utility model provides a kind of new electric blanket protector, and it can detect potential faults in the budding stage, stops further developing of accident; Simultaneously, this protector also should have overvoltage and under-voltage protection function.

This novel purpose is to realize by sample circuit and the protective circuit that redesigns protector.Below with reference to drawings and Examples to this novel being described in further detail.

Fig. 1 is a theory diagram of the present utility model.

Fig. 2 is circuit theory diagrams of the present utility model.

This is novel to be to improve to form on the basis of former electric blanket protector; former protector is made up of main power source 1, DC power supply 2, sample circuit 3, amplifying circuit 4, promotion level 5, output stage 6 and execution relay J; wherein; sample circuit is used for the detection failure signal, and amplifying circuit, promotion and output stage are amplified to this signal is enough to make the relay J action.One group of normally-closed contact of relay J is connected on electric blanket load RL among the main power circuit, is about to electric blanket and cuts off from main power source when relay J is moved.

This novel improvement mainly is, sample circuit adopts bridge circuit, be that load resistance RL is connected in series with resistance R 1, resistance R 2 and potentiometer W serial connection, then be attempted by on one group of normally-closed contact of relay J, the other end of normally-closed contact then is connected on the main power source through K switch, the P of bridge circuit, Q point connects the primary coil of signal transformer B, and detected signal outputs to amplifying circuit through secondary coil.

In order to solve the unsafe factor that produces because of voltage fluctuation is excessive, this novel overvoltage and under-voltage protecting circuit of having installed additional.Overvoltage and under-voltage signal are detected by corresponding sample circuit, the action that detected signal goes to control output stage and carries out relay, and reaching transfinites cuts off the purpose of electric blanket power supply.

What detect overvoltage is overvoltage sample circuit 7, and sample circuit is by diode D2, D3, D4, and resistance R 5, R6, R7, R8 and coupling capacitance C2 form, and wherein, is connected on the main power source after D2, R5, the R6 serial connection, is used to detect the fluctuation situation of power supply.Be connected on the DC power supply after R7, the R8 serial connection, provide reference voltage by it, D3 is connected on A, the C point, and the signal that C is ordered outputs on the base stage of output stage T3 through D4 and C2.When the magnitude of voltage of main power source during, not conducting of D3 in prescribed limit, the output of C point no signal, when voltage surpasses setting, D3 conducting (flash of light simultaneously), signal arrives the ground level of T3 through D4, C2.Make the J action.The supply of cutting off the electricity supply.

Detect under-voltage signal for under-voltage sample circuit 8, sample circuit is by diode D2, D5, D7, resistance R 9, R10, R11, R12, transistor T 4, voltage-stabiliser tube D6 and coupling capacitance C2 form,, wherein be connected on the main power source after D2, R9, the R10 serial connection, detect the voltage fluctuation situation of main power source by it.Be connected on the DC power supply after R11, the R12 serial connection, provide the reference voltage of reference by it.The emitter of T4 connects the H point, and collector electrode meets D7, base stage meets D6, and under-voltage signal is outputed on the base stage of output stage T3 through D5 and C2 by collector electrode.When the magnitude of voltage of main power source was in prescribed limit, T4 was anti-inclined to one side, and the D5 no-output is when under-voltage transfiniting; L point current potential descends, D6, T4 conducting, and the luminous warning of D7, under-voltage signal arrives the base stage of T3 through D5, C2; make J action, the supply of cutting off the electricity supply reaches the purpose of protection.

This DC power supply in novel can be a battery pack, also can adopt the stabilized voltage power supply behind the AC rectification, and power supply shown in Figure 2 is by capacitor C 5, C4, C3, diode D8, voltage-stabiliser tube D9, and inductance L (or resistance) is formed.Wherein, be connected on the main power source after C5 and the D9 serial connection, C5 is a dropping resistor, and D8 is a half-wave rectifier tube, and it is connected to M, N point, and D9 is stabilized in voltage on the required numerical value.C3, C4 and L have constituted an II type filter circuit.

Amplifying circuit 4 during this is novel can adopt the normal transistor amplifying circuit, also can adopt integrated amplifier.It promotes level 5 is made up of transistor T 1, load resistance R3, and the effect of capacitor C 1 is to filter some unnecessary interference, makes the action of relay more reliable.Transistor T 2 in the output stage, T3 are connected into a multiple tube, i.e. the base stage of the collector electrode of T3 and T2, and the base stage of T3 and the collector electrode of T2 link together, and the emitter that diode D10 is connected to T2 is used to indicate " protection " state of electric blanket.In case this connection can be guaranteed the T3 conducting, can be self-locking in conducting state, thereby cut off the supply of electric blanket power supply reliably.

This is novel owing to utilize the impedance detection of electric blanket to obtain guard signal, so, all loose contacts, heated filament fault such as fracture all can detect rapidly, thereby has avoided the fire incident that causes because of sparking that these faults produce, heating etc.In addition, this novel overvoltage or under-voltage protecting circuit can be reacted rapidly when voltage fluctuation, makes the defencive function of electric blanket more become perfect.Can be widely used as the auxiliary products of electric blanket.

Claims

1; a kind of improved electric blanket protector; it is by main power source 1; DC power supply 2; sample circuit 3; amplifying circuit 4; promote level 5; output stage 6 and execution relay J are formed; wherein one of relay J group of normally-closed contact is connected on electric blanket load RL among the main power circuit; receiving fault-signal relay J in season when the sample detecting circuit moves and electric blanket is cut off from main power source; it is characterized in that; sample circuit 3 adopts bridge circuit; be that load resistance RL is connected in series with resistance R 1; resistance R 2 and potentiometer W serial connection; then be attempted by on one group of normally-closed contact of relay J; the contact commonly used other end then is connected on the main power source through K switch; the P of bridge circuit; the Q point connects the primary coil of signal transformer B, and detected signal is exported through secondary coil.

2, electric blanket protector according to claim 1; it is characterized in that it is provided with an overvoltage sample circuit 7; sample circuit is by diode D2, D3, D4, and resistance R 5, R6, R7, R8 and coupling capacitance C2 form, wherein; be connected on the main power source after D2, R5, the R6 serial connection; be used to detect the fluctuation situation of power supply, be connected on the DC power supply after R7, the R8 serial connection, provide reference voltage by it; D3 is connected on A, the C point, and the signal on the C point outputs on the base stage of output stage through D4 and C2.

3, electric blanket protector according to claim 2; it is characterized in that; it is provided with a under-voltage sample circuit 8; sample circuit is by diode D2, D5, D7; resistance R 9, R10, R11, R12; transistor T 4, voltage-stabiliser tube D6 and coupling capacitance C2 form; wherein be connected on the main power source after D2, R9, the R10 serial connection; be connected on the DC power supply after R11, the R12 serial connection, provide reference voltage by it, the emitter of T4 connects the H point; collector electrode meets D7, base stage meets D6, and under-voltage signal is outputed on the base stage of output stage through D5 and C2 by collector electrode.

4, according to claim 1 or 2 or 3 described electric blanket protectors; it is characterized in that DC power supply circuit is by capacitor C 5, C4, C3; diode D8, voltage-stabiliser tube D9; inductance L is formed; wherein; be connected on the main power source after C5 and the D9 serial connection, D8 is connected to M, N point, and C3, C4 and L constitute an II type filter circuit.