JPH01155821A - Control circuit for power-driven rotary brush in electric cleaner - Google Patents

Abstract

PURPOSE: To remove the cause of over-current and make a vacuum cleaner possible to reuse rapidly by connecting a shape memory alloy to a switch in an electric series and further connecting a lever of the switch to the shape memory alloy mechanically. CONSTITUTION: A shape memory alloy 1 is connected with a switch 3 in an electric series, and an over-current shut-down circuit lever of the switch 3 mechanically jointed to the alloy 1 is prepared. In addition, the shut-down circuit is also mounted in an electric source line of motor-drive rotary brush. As a result, if removing the locked cause of a motor to return on the switch, the vacuum cleaner can be reused immediately.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control circuit for a power-driven rotating brush of a vacuum cleaner.

BACKGROUND OF THE INVENTION As shown in FIG. 3, a conventional power-driven rotating brushed nozzle (suction port) of a vacuum cleaner has a rotating brush 8 provided inside a main body 7 and connected to a motor 10 via a belt 9. It was rotating. This motor 10 is controlled by a circuit shown in FIG. 4, and a power supply II is connected in series to the motor 1G via a switch 12, a current limiting resistor RI3, and a positive characteristic thermistor RI4. As shown in FIG. 5, the positive characteristic thermistor RI4 has a characteristic that its resistance value increases above a predetermined temperature, and its current-voltage characteristics are as shown in FIG. 6.

If the motor IO is locked due to some external factor, the current will increase, but this current value is the current maximum point! . If the value exceeds , the voltage falls within a certain range, so the voltage and current value is maintained at a point where the heat dissipation of the positive temperature coefficient thermistor and the amount of self-heating are balanced. In this way, it works to prevent excessive current from flowing into the motor.

Problems to be Solved by the Invention However, in the conventional circuit as described above, due to the heat capacity and heat dissipation characteristics of the self-holding and positive temperature coefficient thermistors, - once the motor is locked, after turning off the power switch. , unless you wait for a while until the temperature of the positive temperature coefficient thermistor R14 falls and the current-voltage characteristics enter the 1F characteristic region.
There was a problem that it could not be used even if it was reinserted.

The purpose of the present invention is to solve the above-mentioned problems, remove the cause of the motor locking, and turn on the switch again.
It is an object of the present invention to provide a control circuit for a power-driven rotating brush that can be immediately reused.

Means for Solving the Problems In order to achieve the above object, the present invention electrically connects a shape memory alloy and a switch in series, and mechanically connects a lever of the switch to the shape memory alloy. The present invention provides a control circuit for a power-driven rotary brush of a vacuum cleaner, in which the overcurrent cut-off circuit is provided in the power line of the power-driven rotary brush.

Effect of the present invention With the above-described configuration, when the load current increases beyond a predetermined value for some reason, the shape memory alloy deforms into the shape memorized at the time of manufacture, and in conjunction with this, the switch lever changes. can be moved to interrupt the circuit current.

In addition, shape memory alloys have a small heat capacity, so heat dissipation is
<Once the cause of the overcurrent has been removed, it can be restored immediately by turning on the cut-off switch.

Embodiment FIG. 1 shows an embodiment of a control circuit for a power-driven rotating brush according to the present invention.

In FIG. 1, 1 is a shape memory alloy, which is electrically connected in series with a switch 3 and a current limiting resistor 2, and this shape memory alloy 1 is mechanically connected to a lever of the switch 3. 4 is negative -; I is the motor, 5 is the main switch,
6 is a power source.

FIG. 2 is a characteristic diagram showing general temperature and displacement of shape memory alloy I. It is shown that when an electric current is applied to the shape memory alloy to cause it to self-heat, or when the ambient temperature changes and exceeds To shown in FIG. 2, the shape changes to the shape memorized at the time of manufacture.

In the above configuration, when the load current increases due to locking of the motor 4, etc., the shape memory alloy l is displaced due to self-heating, and the switch 3 linked to this displacement is driven to cut off the circuit current of the power-driven rotating brush. It functions as an overcurrent cutoff circuit.

If a locking mechanism is added to the switch 3, an overcurrent cutoff circuit with a self-holding function will be achieved. Because the current is interrupted as above.

Furthermore, since the heat capacity of the shape memory alloy is small, it can be used by immediately turning on the switch 3 again after the cause of the overcurrent is removed.

Effects of the Invention As described above, in the present invention, the shape memory alloy and the switch are electrically connected in series, and the lever of this switch is mechanically connected to the shape memory alloy, thereby eliminating the cause of overcurrent. After that, it can be reused immediately. Furthermore, the present invention provides a control circuit for a power-driven rotary brush of a vacuum cleaner, which does not require a complicated drive mechanism such as a motor or a plunger as a drive element for a switch, so that a predetermined purpose can be easily achieved at low cost.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram shown as an example of the present invention, Fig. 2 is a characteristic diagram showing a general temperature and displacement relationship of a shape memory alloy,
FIG. 3 is a perspective view of a power-driven rotating brush nozzle, FIG. 4 is a conventional control circuit, and FIGS. 5 and 6 are characteristic diagrams of a positive temperature coefficient thermistor.

Claims (1)

[Claims] An overcurrent cutoff circuit is provided in which a shape memory alloy and a switch are electrically connected in series, and a lever of the switch is mechanically connected to the shape memory alloy, and the overcurrent cutoff circuit is provided in the power supply line of the power-driven rotating brush. A control circuit for a power-driven rotating brush of a vacuum cleaner, characterized in that the circuit is provided.