JPH0658177B2 - Surface heating tool - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface heating tool for a carpet or the like using a heater.

2. Description of the Related Art In a conventional carpet temperature control circuit, as shown in FIG. 4, a temperature signal voltage V _T of a temperature detection circuit 3 and a reference voltage V _R of a reference voltage setting circuit 4 are input to a comparison circuit 5 for comparison. When the temperature signal voltage V _T becomes higher than the reference voltage V _R , a HI signal is output from the comparison circuit 5, the transistor 73 is turned on, and the relay 72 operates to operate the contact 72a of the relay 72.
Is turned on to energize the heater 8 and / or the heater 9. Along with this, the hysteresis circuit 6 is connected in parallel with the resistor 44 of the reference voltage setting circuit 4, and the reference voltage V _R becomes lower, so that the drive circuit 7 becomes more and more operable. That is, hysteresis is given. A changeover switch for changing over the heating area is composed of S ₁ , S ₂ , and S ₃ , and they are interlocked with each other.

When the temperature signal voltage V _T becomes lower than the reference voltage V _R , the drive circuit 7 is turned off and the contact 72a of the relay 72 is turned off.
However, the heater 8 and / or the heater 9 is turned off, and the hysteresis circuit 6 is not connected in parallel with the resistor 44 of the reference voltage setting circuit 4.

Problems to be Solved by the Invention In such a conventional sheet heating device, the temperature signal voltages (V _T1 and V _{T2 in} FIG. 3) at the time of full-surface heating and at the time of single-side heating are different except at a high temperature. . However, since the reference voltage (V _R1 or V _{R2 in} FIG. 3) is the same, the surface temperature of the carpet is different (t ₁ , t ₂ and t ₃ , t _{4 in} FIG. ₃ ), and
Since the amount of hysteresis is constant (V _R1 −V _{R2 in} FIG. 3), the intervals of energization and de-energization of the heater 8 and / or 9 are different. That is, the temperature must be adjusted when the heating area is switched, and the sensible temperature is different because the interval between energization and de-energization of the heater 8 or / and 9 is different.

The present invention has been made in view of the above point, and provides a surface warming tool such as a carpet in which the surface temperature of the carpet does not change when the heating area is switched and the intervals of energization and de-energization are substantially the same. It is an object.

Means for Solving the Problems The present invention, in order to solve the above problems, interlocks with a changeover switch for changing over a heating area to change the resistance value of a temperature detection circuit and a reference for a temperature signal voltage and a reference voltage setting circuit. It has a varying means for varying the voltage and the amount of hysteresis of the hysteresis circuit.

Operation According to the present invention, when the changeover switch for changing the heating area is operated, the reference voltage and the amount of hysteresis change at the same time as the temperature signal voltage, so that the above object can be achieved.

Embodiment FIG. 1 is an embodiment of a temperature control circuit in the surface heating tool of the present invention, and FIG. 2 is an embodiment showing the main body structure of the surface heating tool of the present invention. FIG. 3 shows detected temperature vs. reference voltage and temperature signal voltage in the surface heating tool of the present invention.

The same number and the same symbol indicate the same thing.

In the figure, 1 is a commercial power supply, 2 is a power switch, 3 is a temperature detection circuit, and 31, 32, 33 and 37 are resistors. S ₃ is a switch for switching between full heating and single heating, and the figure shows the time of full heating. Reference numeral 34 is a temperature sensor that detects the temperatures of the heating elements 8 and 9. 35 is a diode, 36
Is a capacitor.

Reference numeral 4 is a reference voltage setting circuit, which is 41, 42, 44, 45.
Is a resistance, and 43 is a variable resistor used as a temperature controller.

5 is a comparison circuit, 6 is a hysteresis circuit, 61, 6
2 is a resistor and 63 is a diode. 7 is a drive circuit for energizing the heaters 8 and 9 used as heating elements, 73 is a transistor, 71 is a diode, 72 is a relay, 72
a is a contact of the relay. S ₁ , S ₂ , and S ₄ are changeover switches that interlock with the changeover switch S ₃ . Reference numeral 10 is a main body of the carpet.

Next, the operation will be described.

When heating the entire surface (state shown), the resistor 31 and the temperature sensor 34
The voltage obtained by dividing the commercial power supply voltage is rectified by the diode 35 and smoothed by the capacitor 36, and the temperature signal voltage V _T1 and the reference from the reference voltage setting circuit 4 are rectified. _Are compared by the comparison circuit 5, and when the temperature signal voltage V _T1 is larger than the reference voltage V _{R1, a} Hi signal is output from the comparison circuit 5, the relay 72 operates, the contact 72a is closed, and the heater 8 and the heater 9 are closed. While being energized, the hysteresis circuit 6 is connected to the ground side of the circuit, And, as the carpet temperature increases, it works.

V _{R1, V R2} See FIG. 2, the resistance value of R _41, the other is the same.

At this time, when the changeover switch S _{3 is set} to the one-side heating side, the temperature signal voltage is changed by the changeover switch S ₃ from the resistance 32 to the resistance 3
1 is connected in series, the temperature signal voltage V _T2 becomes lower than the temperature signal voltage V _T1 on the entire heating side, but at the same time, the reference voltage becomes Next to Becomes By selecting R ₆₁ and R _{45 such} that V _R3 = V _T2 and V _R4 = V _T2 , the hysteresis amount also changes at the same time, that is, the same temperature during full heating and single heating, that is, t ₁ and t _{2 in} FIG. It is possible to keep

In addition, the interval between energization and de-energization is substantially the same, and the life of energization control parts such as relays can be made the same, which is a very practical sheet heating tool.

EFFECTS OF THE INVENTION As described above, according to the present invention, the reference voltage and the amount of hysteresis change at the same time as the temperature signal voltage without changing the temperature controller when switching the heating area, and the carpet surface temperature does not change and is comfortable. Will be things.

[Brief description of drawings]

FIG. 1 is a control circuit diagram of a planar heating tool according to an embodiment of the present invention,
FIG. 2 is a plan view showing a main body configuration of the surface heating device.
FIG. 3 is a diagram showing the detected temperature versus the reference voltage and the temperature signal voltage in the surface heating tool. FIG. 4 is a control circuit diagram of a conventional example. 3 ... Temperature detection circuit, 4 ... Reference voltage setting circuit, 5 ...
Comparator circuit, 6 ...... hysteresis circuit, 7 a drive circuit for energizing the ...... heating element, _{V T} ...... temperature signal voltage, _{V R} ...... reference _{voltage, S 1, S 2, S} 3, S 4 ...... Heating Changeover switch for changing the area.

Claims (2)

[Claims] 1. A main body, a heating element dividedly arranged in the main body, a changeover switch for switching energization to the divided heating element, and a control circuit for controlling energization of the heating element.
A temperature sensor that detects the temperature of the heating element and transmits a temperature detection signal to the control circuit, the control circuit includes a temperature detection circuit in which a resistor is connected to the temperature sensor, a reference voltage setting circuit, and the reference voltage. The reference voltage of the setting circuit and a comparison circuit that compares the temperature signal voltage from the temperature detection circuit, a hysteresis circuit that gives a hysteresis to the output of the comparison circuit, and the heat generation based on the output of the comparison circuit to which the hysteresis is added. A drive circuit for urging the body, and a variable means for varying the temperature signal voltage of the temperature detection circuit, the reference voltage of the reference voltage setting circuit, and the hysteresis amount of the hysteresis circuit in conjunction with the switching of the changeover switch. Surface heating tool with. 2. The planar warming tool according to claim 1, wherein the reference voltage of the reference voltage setting circuit and the hysteresis amount of the hysteresis circuit are switched by a common contact.