JPH0817821B2 - Warming tool - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heating tool, and more specifically, to a heating circuit having a negative potential with respect to the ground regardless of the insertion direction of a power plug. Thus, the present invention relates to a heating tool that eliminates the generation of positive potential.

[Conventional technology]

It has been conventionally known that a therapeutic effect such as stiff shoulder can be obtained by disposing an electrode kept at a negative potential near a human body, and it has been conventionally attempted to incorporate such a therapeutic device into a heating device.

For example, Japanese Patent Application Laid-Open No. 62-74373, in which heat is generated in a positive cycle of an AC power supply and the heating circuit is insulated from the power supply in the negative cycle and a negative potential is applied to the insulated circuit. There is technology. In the prior art of this publication, as shown in FIG. 4, a heater circuit including an electric heater 1, a power control rectifying element 2 composed of an SCR and a temperature fuse 4, and a power supply 6 when this circuit is in a negative cycle.
A main current circuit is composed of an isolation switch element (SCR) 8 and a diode 10 which are isolated from
Are connected in parallel to the power supply 6 to form a power supply circuit of the control circuit 14. Reference numeral 16 denotes a high voltage generating transformer, which is adapted to give a negative potential to the heater circuit and control circuit 14 through the high voltage generating transformer 16, the diode 17 and the resistor 18. The circuit of FIG. 4 has a heat-sensitive layer 20 whose impedance changes with temperature,
A signal line 22 for detecting the impedance change of the heat sensitive layer 20.
Are provided to detect the temperature of the heat sensitive layer 20 and apply a temperature signal to the control circuit 14 and the fusing resistor 24 of the thermal fuse 4.

[Problems to be Solved by the Invention]

By the way, when the ground electrode is connected as shown by the solid line in the circuit of FIG. 4, the anode of the power control rectifier element 2 is connected to the ground electrode side, and as shown in FIG. Then, as shown in the middle of FIG. 5, the electric heater 1
When a current is supplied to the electric heater 1, a portion of the electric heater 1 has a zero potential, a central portion b has a negative potential of half the peak value, and a portion c has a negative voltage drop of the peak value. While generating heat. Further, when the power control rectifying element 2 is off, the a, b, and c parts have zero potential, and no positive potential is generated. However, when the polarity of the power source 6 is reversed and the ground electrode is connected as shown by the dotted line in FIG. 4,
As shown in the lower part of FIG. 5, when a current is supplied to the electric heater 1, a part of the electric heater 1 has a positive potential of a peak value, b part thereof has a positive potential of ½ of the peak value, with reference to the ground. The part c generates a voltage drop of zero potential to generate heat, and when the power control rectifier 2 is off, positive potentials with peak values are generated in parts a, b, and c respectively, which is generally considered to be harmful and harmful to the human body. There is a problem that the known positive potential is generated.

However, since the single-phase commercial AC power supply does not indicate which pole is grounded, it cannot be used by limiting the insertion direction of the power plug.

The present invention has been made in view of the above problems, and has a built-in means for detecting the ground side of a power supply without attaching a special electrode and always connecting a negative voltage generating circuit to the ground side of the power supply. , The purpose of the present invention is to provide a heat collecting tool that generates heat in the negative potential side cycle with respect to earth.

[Means for solving the problem]

The configuration of the heating tool of the present invention for achieving the above object is that the heating tool circuit selects a power supply circuit, a heater circuit provided with a power control rectifying element, and a connection polarity between the power supply circuit and the heater circuit. And a connection terminal selection circuit. The connection terminal selection circuit is formed of a delay switch circuit described below, an earth line detection circuit for detecting the ground pole of the power supply, and a changeover switch circuit.

That is, the insulating switch of the delay switch circuit forms a capacitor having the heater circuit as one pole and the other pole as the ground by insulating the heater circuit from the power circuit when the insulating switch is opened. The power control rectifier of the circuit is configured to detect whether the anode is on the ground electrode side or not, and when closed, connects the heater circuit to the power supply circuit, and the drive circuit of the isolation switch connects the power supply to the power supply circuit. Then, the delay action works to close the isolation switch after a lapse of a certain time, and opens when the power supply is disconnected.

As the delay means provided in the delay switch circuit, for example, a general delay circuit utilizing a charging time of a capacitor can be used, but the delay means is not limited to this and a known delay means can be appropriately used.

The earth line detection circuit detects a current flowing to the ground through one pole of the power supply circuit and the heater circuit to detect whether the one pole is the ground of the power supply.

Further, the changeover switch circuit is formed by a changeover switch that connects the anode side of the power control rectifying element to the ground electrode of the power supply according to the output signal of the earth line detection circuit.

Further, the present invention may be arranged such that the heating tool circuit is provided with a voltage doubler circuit so that the heater circuit is insulated from the power source and gives a negative high potential during the negative cycle of the power control rectifying element.

The warming tool as referred to in the present invention means a sleeping warming tool such as an electric blanket, a warming tool such as an electric carpet and an electric cushion, and a thermotherapy device.

〔Example〕

Hereinafter, a warming tool of the present invention will be described in detail by way of an embodiment with reference to the accompanying drawings.

FIG. 1 is a block diagram for explaining the outline and operation of the heat collecting tool of this embodiment. In the figure, the heat collecting tool 26 is
Heater circuit 28 and power supply circuit provided with power control rectifying element 2
And a connection terminal selection circuit 32 provided between the connection terminal 30 and the connection terminal. The outlet 34 is a supply terminal of the commercial power source 6, and one pole thereof is grounded. And the power supply circuit 30
A plug 36 connected to the outlet 34, a main switch SW, a transformer 12 ′ which is a power supply circuit for the connection terminal selection circuit 32, and a DC power supply circuit 37.

The connection terminal selection circuit 32 includes a delay circuit 38 and this delay circuit.
Relay circuit RY ₁ driven by 38 and this relay circuit R
A switch closing delay circuit 39 constituted by an insulating switch RY ₁ -K driven by Y ₁ , a relay circuit RY ₂ driven by an earth line detection circuit 40, and a changeover switch RY driven by this relay circuit RY _2. It is composed of a changeover switch circuit 41 composed of _2- K. Each of the relay circuits can be configured by a contactless circuit.

As the detection electrode when the earth line detection circuit 40 detects the earth line, one pole wire of the power supply 6 connected to the heater circuit 28 and one line 42 of the power supply circuit 30 is used. Therefore, the heater circuit 28 and the earth line detection circuit 40,
A line 44 connected through a high impedance resistor R ₀ is connected, and the line 42 and the earth line detection circuit 40 are connected to each other.
It is connected by a line 46 on the low voltage side of the DC power supply circuit 34.

Next, the operation of the circuit shown in FIG. 1 will be described. When the plug 36 is connected to the outlet 34 (in the state shown in the figure) and the main switch SW is turned on, power is supplied to the delay circuit 38 and the earth line detection circuit 40. Then, the delay circuit 38
Turning on the isolating switch RY ₁ -K after a predetermined time has elapsed. During this time, that is, while the main switch SW is turned on and before the insulation switch RY ₁ -K is closed, power is not supplied to the heater circuit 28, the earth line detection circuit 40 performs the earth line detection operation.

The earth line detecting operation utilizes the fact that the heater circuit 28 and the ground E form a capacitor C ₀ as shown in FIG. That is, when the plug 36 is inserted into the outlet 34 as shown, the lines 42 and 46 are connected to the ungrounded side of the power source. In this case, the alternating current I _{0 from the} power source 6 flows through the capacitor C ₀ .

However, if the plug 36 is inserted in the reverse direction and the line 42 of the power supply circuit 30 is connected to the ground E side, both electrodes of the capacitor C ₀ have the same potential, so that no current flows. The earth line detection circuit 40 detects this difference in current and drives the changeover switch RY ₂ -K so as to connect the ground electrode of the power supply 6 to the anode side of the power control rectifier element 2 (from the state shown in the figure to the contrary. Switched state). If the time constant of the delay circuit 38 is set to an appropriate value, the insulation switch RY ₁ -K is closed and power is supplied to the heater circuit 28 when this switching operation (in some cases, it is not switched and remains unchanged). To be done. Therefore, how to plug 36 into outlet 34
Even if you insert it regardless of the polarity of the connection terminal selection circuit 32
Can always connect the anode side of the power control rectifier 2 to the ground E side of the power supply 6.

Next, the essential parts of the circuit shown in FIG. 1 will be specifically described with reference to FIG. In FIG. 2, a voltage doubler circuit 48 that provides a high negative potential is provided.

In FIG. 2, the earth line detection circuit 40 detects the voltage generated in the electrolytic capacitor C ₁ by the current I ₀ flowing through the capacitor C ₀ in FIG. ₁ by the OP amplifier U2A, and inputs this detection signal to the OP amplifier U1A. The control signal output to the relay circuit RY ₂ is obtained. Relay circuit RY ₂ solenoid Y
_The switching switch RY ₂ -K connects the ground line of the power supply 6 to the anode side of the power control rectifier ₂ by the transistor Q _{2 which} is operated by the control signal.

The delay switch circuit 39, after the main switch SW is turned on, detects the voltage change determined by the time constant of the capacitor C ₂ and the resistor R ₉ and the divided voltage value of the resistors R ₁₀ and R ₁₁ in the OP amplifier.
U2B compares and detects the decrease in the voltage generated in the resistor R ₉ as the charging of the capacitor C ₂ progresses, drives the transistor -Q ₁ and closes the isolation switch RY ₁ -K to supply power to the heater circuit 28. Discharge circuit 50 a condenser C ₂ is discharged when the power is cut off, the capacitor C ₂ to be actuated to initialize the delay switch circuit 18 when again the power immediately after turning off the power supplied Is a switch circuit that discharges.

Voltage doubler circuit 48, a capacitor C ₃ -C ₈ and the diode
Using D ₃ to D _8, obtained by connecting a conventional voltage doubler circuit in cascade, so that to generate a high pressure in the case of FIG 600V, providing this voltage to the heater circuit 28. Therefore, when the current flowing through the electric heater 2 during the negative cycle of the power control rectifying element 2 is cut off, the heater circuit 28 can be insulated from the power source by the insulating switch element 8 and the diode 10 to give a negative potential.

In FIG. 2, the circuit 52 is a drive circuit for the insulating switch element 8, and the control circuit 14 is the control circuit of FIG.
The same circuit as that of 14 is used, and details are omitted. Also, the second
In the figure, the temperature fuse blowing means, the noise removing means, and other various safety means when the temperature rises excessively are omitted because they are complicated.

FIG. 3 is a graph showing the operation of the circuit shown in FIG. In the figure, when power is applied to the warming tool 26, no matter which line of the power circuit 30 the ground line of the power source 6 is supplied to, as shown in FIG. In the cycle, when a current is supplied to the electric heater 1, a negative potential voltage drop occurs with respect to the ground to generate heat, and when the temperature is high, the control circuit 14 causes the power control rectifying element 2 to operate. The electric current of the electric heater 1 is cut off. Then, since no voltage drop occurs in the electric heater 1, the ground and the electric heater 1 as a whole have the same electric potential and become zero electric potential. In the cycle of the negative power source 6 of the power control rectifier element 2, the power control rectifier element 2 reversely blocks, so that the electric heater 1 has the same potential as the ground and zero potential. Therefore, when the electric heater 1 is energized, a negative potential is generated with respect to the ground, and at other times, it becomes a zero potential and no positive potential, which is harmful and useless, is not generated.

〔The invention's effect〕

As described above, the warming tool of the present invention is provided with the ground electrode detecting means that does not require special electrode attachment, and the ground side of the power source can be automatically connected to the anode side of the power control rectifier. During use of the warming tool, heat can be generated on the negative potential side with respect to the ground, and at the same time as warming, a therapeutic effect or health effect due to the negative potential can be given.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of a heating tool of the present invention according to an embodiment, FIG.
Fig. 1 is a ground pole detection circuit diagram of Fig. 1, Fig. 3 is a graph diagram for explaining the operating state of the circuit of Fig. 1, Fig. 4 is a circuit diagram of a conventional heating tool, and Fig. 5 is Fig. 4 It is a graph which shows the operation state of the circuit shown. 1 ... Electric heater, 2 ... Power control rectifier, 6 ...
Commercial power supply, 30 ... Power supply circuit, 32 ... Connection terminal selection circuit,
39 …… Delay switch circuit, 40 …… Earth line detection circuit, 48 …… Double voltage circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-57-195472 (JP, A) Actually opened 61-21546 (JP, U) Actually opened 58-1452 (JP, U)

Claims (2)

[Claims] 1. A warming tool circuit includes a power supply circuit, a heater circuit provided with a power control rectifying element, and a connection terminal selection circuit for selecting a connection polarity between the power supply circuit and the heater circuit. The selection circuit is formed by a delay switch circuit, an earth line detection circuit that detects a ground electrode of a power supply, and a changeover switch circuit, and the delay switch circuit includes an insulation switch and a drive circuit. When the AC power supply is connected to the power supply circuit, the insulating switch is closed with a delay, and when the power supply is cut off, the switch is opened to electrically cut off the heater circuit from the power supply circuit. Detecting the current flowing through the ground through one pole of the power circuit and the heater circuit,
Detecting whether the one pole is on the ground side of the AC power supply, the switching switch circuit controls the anode side of the power control rectifying element to the AC power supply by the control signal output from the earth line detection circuit. A warming tool formed by a changeover switch connected to the grounding electrode of. 2. A power control rectifying element for controlling an electric heater insulates the heater circuit from a power supply circuit during a negative cycle of the power control rectifying element for interrupting a current flowing through the heater circuit, and is supplied from the polarity changeover switch means. The warming tool according to claim 1, further comprising a negative potential circuit that applies a predetermined negative potential to the heater circuit by a voltage doubler circuit of a power source.