JPH0559390B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention is installed in washrooms, toilets, etc.
The present invention relates to a hand dryer that dries hands that have been washed with water using warm air, and more specifically relates to a mounting structure for an ultrasonic sensor that detects hands. [Prior art] Conventionally, as a hand dryer, an ultrasonic wave is installed near the hot air outlet, and this ultrasonic sensor outputs ultrasonic waves to the hot air outlet side, and the reflected waves are used to stimulate the hand held over the hot air outlet. Some devices detect this and blow out warm air from a hot air outlet. [Problems to be Solved by the Invention] However, in the above hand dryer, immediately after the hand is out of the sensing range of the ultrasonic sensor and the energization of the motor, heater, etc. is terminated, the air volume decreases as the motor rotation speed decreases. Therefore, the outlet temperature may rise due to the amount of heat remaining in the heater.
When this air whose temperature has increased flows toward the output direction of the ultrasonic waves due to the weak air flow after the energization ends, the ultrasonic waves are disturbed. Then, there is a problem in that the ultrasonic sensor receives a disturbed reflected wave from the crosspiece of the hand dryer, misidentifies it as a hand, and causes the hand dryer to malfunction. This invention was made to solve the above problems, and its purpose is to prevent the disturbance of ultrasonic waves caused by the temperature rise in the vicinity of the hot air outlet immediately after the end of energization of the heater and blower fan. An object of the present invention is to provide a sensor mounting structure for a hand dryer that can prevent malfunctions. [Means for Solving the Problems] In order to achieve the above object, the present invention includes a heater that heats air, a blower fan that blows air to the heater and blows out warm air from the hot air outlet, and an ultrasonic sensor that is installed adjacent to the hot air outlet and outputs ultrasonic waves toward the hot air outlet, receives reflected waves, and detects a hand placed at the hot air outlet; In the hand dryer, the heater and the blower fan are energized and driven to blow out hot air from the hot air outlet based on the hand detection result, and the ultrasonic sensor and the hot air outlet are connected between the ultrasonic sensor and the hot air outlet. The gist of this invention is a sensor mounting structure for a hand dryer that is provided with a partition wall to prevent warm air from going around in the output direction of sound waves. Further, the ultrasonic sensor may be installed so that the output direction of the ultrasonic wave is inclined by 10° to 20° toward the hand insertion direction with respect to the hot air blowing direction. [Function] Therefore, the air near the hot air outlet, whose temperature has risen immediately after the end of energization of the heater and blower fan, is prevented from going around in the direction of ultrasonic output by the partition wall, so that the air that is output from the ultrasonic sensor is Disturbance of ultrasonic waves due to temperature is prevented. In addition, by installing the ultrasonic sensor so that the output direction of the ultrasonic wave is inclined 10° to 20° toward the hand insertion direction with respect to the hot air blowing direction, the sensing range of the ultrasonic sensor is Since it deviates from the blowing direction, disturbances due to temperature of the ultrasonic waves are reliably prevented. [Example] Hereinafter, an example embodying the present invention will be described as follows.
This will be explained according to FIG. FIG. 1 shows a hand dryer 1, and a mounting plate 2 arranged and fixed inside a case (not shown) has a duct 3.
is installed, and a motor 4 is installed at the top of the duct 3.
A fan/motor unit 6 is provided which includes a blower fan 5 and a blower fan 5 driven by the motor 4.
Moreover, between the atsupa duct 3a at the bottom of the duct 3 and the lower duct 3b equipped with the hot air outlet 3c,
A heater 7 having PTC (positive temperature coefficient) characteristics,
A heater section 9 consisting of heat radiation fins 8 and the like is provided. When the motor 4 drives the blower fan 5 and the heater 7, the air is heated as it passes through the heat radiation fins 8, and warm air is blown out from the hot air outlet 3c. A pair of ultrasonic sensors 10 for both transmitting and receiving purposes are attached to the left and right side walls of the lower duct 3b so that the output direction of the ultrasonic waves intersects the hot air blowing direction, and each ultrasonic sensor 10 detects reflected waves. Accordingly, an object (hand) placed in the sensing range below the hot air outlet 3c is detected. Further, as shown in FIGS. 1 and 2, on the left and right side walls of the lower duct 3b, there are partition walls 3 for preventing hot air from flowing around from the vicinity of the hot air outlet 3c toward the ultrasonic output direction side.
4 are integrally provided. On the other hand, both ultrasonic sensors 1 are mounted on the mounting plate 2.
a control circuit 11 for driving the fan motor section 6 and the heater section 9 based on the detection signal from 0;
A control panel C is installed. Further, a transformer 13, a triax 14, a switch 15, a fuse 16, etc., which constitute the power supply section 12, are attached to the mounting plate 2. Next, the electrical configuration of the hand dryer is
This will be explained based on the diagram. The motor 4 and heater 7 are connected in parallel to the power supply section 12, and in this embodiment, these are driven at 100 volts AC. Further, a voltage step-down circuit 18 is connected to the power supply section 12 via a terminal terminal 17 for supplying the drive power V2 to the control circuit 11. The step-down circuit 18 includes a full-wave rectifier 19, capacitors C1 to C4, and a resistor R.
1 and a voltage divider 20, and outputs a DC driving power supply V2 (12 volts in this embodiment) which is a step-down and rectified 100 volt AC power supply.
Further, this step-down circuit 18 is adapted to supply a driving power source V1 to a display 21 that indicates that the motor 4 and heater 7 are being driven. The control circuit 11 includes an oscillation circuit 22 and an amplifier circuit 2.
3. Consists of a determination circuit 24 and a timer circuit 25,
The ultrasonic sensor 10 is connected to an oscillation circuit 22 and an amplification circuit 23. The oscillation circuit 22 includes an oscillation IC 26, a variable resistor R3,
Consisting of resistors R2, R4, capacitors C5, C6, variable resistor R3, resistor R2, and capacitor C6
signal determined by the constant (40.5kHz in this example)
is output to the ultrasonic sensor 10 via a resistor R4. The amplifier circuit 23 includes amplifiers 27 to 29, capacitors C7 to C9, variable resistor R5, and resistors R6 to R10, and the amplifier 27 converts a current signal according to the reflected wave received by the ultrasonic sensor 10 into a voltage signal, The amplifier 28 detects the strong and weak parts of the reflected wave (2 to 20Hz)
The amplifier 29 further amplifies the output signal of the amplifier 28 and sends the amplified signal to the judgment circuit 24.
Output to. This is because the waves reflected from a fixed object do not change in strength, but the ultrasound reflected from a person's hand is distorted and changes in strength due to the movement of the hand, so this distortion occurs. The device detects the hand by amplifying only the hand part. The judgment circuit 24 includes a comparator 30 and a resistor R11.
~ R13, which compares the reference voltage determined by resistors R11 and R12 with the amplified signal from the amplifier circuit 23, and outputs an on signal to the next stage timer circuit 25 when the amplified signal is larger than the reference voltage. I'm starting to do that. The timer circuit 25 includes counters 31 and 32, and a resistor R.
14, R19, capacitors C10 to C13, and a diode D1, and turns on the transistor 33 based on the on signal from the determination circuit 24 to turn on the triax 14 of the power supply section 12,
The motor 4 and heater 7 are driven. Next, the operation of the hand dryer configured as described above will be explained. When the switch 15 is turned on to turn on the power, the oscillation circuit 22 sends a 40.5kHz signal to both ultrasonic sensors 10, and both ultrasonic sensors 10 send out ultrasonic waves. When there is an object within the sensing range of both ultrasonic sensors 10, the ultrasonic waves are reflected, and the returned reflected waves are received by both ultrasonic sensors 10 and converted into current signals. This current signal is transmitted to the amplifier 27 of the amplifier circuit 23.
is converted into a voltage signal, and only the low frequency signal (approximately 2 to 20 Hz) that is detected by the hand is amplified by the next stage amplifier 28. The output signal from the amplifier 28 is amplified by the amplifier 29 and the amplified signal is output to the determination circuit 24. Then, the amplified signal of the amplifier 29 is transmitted to the determination circuit 24.
When the amplified signal is larger than the reference voltage, the determination circuit 24 outputs an ON signal to the timer circuit 25, and the timer circuit 25 turns on the transistor 33 for a predetermined period of time (1 to 3 in this embodiment).
(about seconds). This transistor 3
3, the triax 14 of the power supply section 12 is turned on, and the motor 4 and heater 7 are driven by a power source of AC 100 volts, and warm air is blown toward the hand from the hot air outlet 3c. Figure 5 shows the hot air outlet 3c as shown in Figure 4.
It shows the temperature change at the temperature measuring point ~ at a distance of 20cm from . The temperature rise is the largest at the temperature measurement point in the hot air blowing direction l, followed by the temperature measurement point on the side where the hand is inserted into the hot air outlet 3c. The temperature rise is the smallest. At the temperature measuring point in the hot air blowing direction l, the warm air blowing outlet 3c is activated by the operation of the heater 7 and the motor 4.
The temperature of rises as shown by the solid line in Figure 5, reaching approximately
Stable at around 45℃. Immediately after the hand disappears from below the warm air outlet 3c and goes out of the sensing range of the ultrasonic sensor 10, and the heater 7 and motor 4 are stopped, the air volume decreases as the rotational speed of the motor 4 decreases. Heater 7 and lower duct 3
Due to the amount of heat remaining in b, the outlet temperature rises rapidly as shown by the solid line in FIG. However, in this embodiment, the partition walls 34 are integrally provided on both left and right walls of the lower duct 3b to prevent hot air from flowing around from the hot air outlet 3c, so the ultrasonic waves from the ultrasonic sensor 10 are not disturbed. , it is possible to prevent erroneous detection immediately after the end of energization of the heater 7 and the motor 4, thereby preventing the hand dryer 1 from malfunctioning. 6 and 7 show another embodiment. That is, as shown in FIG. 6, in this example, the ultrasonic sensor 10 is connected to
It is attached so as to be inclined by 10° to 20° in the hand insertion direction, and the other configurations are the same as those of the previous embodiment. In this example, as shown in FIG.
Based on the fact that the temperature rise at the temperature measurement point on the side where the hand is inserted is the smallest, the sensing range of the ultrasonic sensor 10 is removed from the hot air blowing direction l, reducing the influence of temperature and transmitting ultrasonic waves. It is possible to reliably prevent disturbances. Then, as shown in FIG. 7, the ultrasonic sensor 10
When tilted toward the installation side of the hand dryer 1 and the hand insertion side with the hot air blowing direction l as the center,
The results shown in the table below were obtained.

[Table] As you can see from the table above, towards the insertion side of the hand +
It can be seen that it works normally when tilted at 10 degrees or more. However, if the hand is tilted by +30° or more toward the hand insertion side, the sensing range of the ultrasonic sensor 10 will deviate significantly from the warm air blowing range. Therefore, it is best to install the ultrasonic sensor 10 so that it is inclined by 10 to 20 degrees toward the hand insertion direction with respect to the hot air blowing direction l. In both of the embodiments described above, the partition walls 34 are integrally provided on both left and right walls of the lower duct 3b, but it goes without saying that the partition walls may be provided separately. [Effects of the Invention] As described in detail above, according to the present invention, the partition wall can prevent hot air from going around from the vicinity of the hot air outlet toward the output direction of the ultrasonic waves. It is possible to prevent the malfunction of the hand dryer by preventing the disturbance of ultrasonic waves caused by the temperature rise near the hot air outlet. In addition, by installing the ultrasonic sensor so that the output direction of the ultrasonic wave is inclined 10° to 20° toward the hand insertion direction with respect to the hot air blowing direction, the sensing range of the ultrasonic sensor will be in the low temperature range. Since the arrangement reduces the influence of temperature, it is possible to reliably prevent disturbance of ultrasonic waves due to temperature and prevent malfunction of the hand dryer.

[Brief explanation of the drawing]

1 to 5 show an embodiment of a hand dryer embodying the present invention, FIG. 1 is an exploded perspective view showing the main parts, FIG. 2 is a front view of the main parts, and FIG. 3 is an electric circuit diagram. Fig. 4 is a diagram for explaining the action, Fig. 5 is a graph showing the relationship between temperature measurement points and temperature, Fig. 6 is a side view showing another embodiment, and Fig. 7 is for explaining the action. This is a diagram. In the figure, 3c is a warm air outlet, 5 is a blower fan, and 7
10 is a heater, 10 is an ultrasonic sensor, and 34 is a partition wall.

Claims (1)

[Scope of Claims] 1. A heater that heats air; a fan that blows air to the heater and blows out warm air from a hot air outlet; an ultrasonic sensor that outputs ultrasonic waves toward the hot air outlet and detects a hand placed at the hot air outlet by receiving reflected waves, and the heater and the blower fan are activated based on the hand detection result by the ultrasonic sensor. In a hand dryer that is driven with electricity to blow out hot air from a hot air outlet, there is a device between the ultrasonic sensor and the hot air outlet that prevents hot air from flowing around from the vicinity of the hot air outlet toward the output direction of the ultrasonic waves. A hand dryer sensor mounting structure characterized by having a partition wall for preventing the problem. 2 Set the ultrasonic sensor so that the output direction of the ultrasonic wave is 10° to 20° toward the hand insertion direction with respect to the hot air blowing direction.
2. The sensor mounting structure for a hand dryer according to claim 1, wherein the sensor mounting structure is mounted so as to be inclined.