JPS62275405A - Apparatus for preventing electric shock of electric machinery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Industrial Field of Application) The present invention provides a method for preventing damage to the human body due to electrical leakage when an electric device such as a hair dryer A7 or a hair eye [1] comes into contact with a conductive substance such as water. The present invention relates to an electric shock prevention device that prevents electric shock to the body.

(Prior art) In recent homes, the restroom is often located in the bathroom. If an AI is accidentally dropped into water such as a bathtub, there is a possibility that it could cause an electric shock accident to the human body.

In order to prevent such electric shock accidents, conventionally an insulating transformer means 2 is provided between the commercial AC source 1 and the electrical equipment 3, as shown in FIG. However, electrical equipment 3
When it comes into contact with a conductive substance, for example water 5, the ground fault current flowing through the path a will not flow to the person 4 present because the isolation transformer means 2 is provided, but the current flowing through the path will cause the earth fault current to flow through the path a. 4 may receive an electric shock. Therefore, the live parts and housing of the electrical equipment 3 are sealed with a sealing member,
Electric shock can be prevented by preventing the current inside the electrical device 3 from leaking to the outside, but there is a drawback that gaps develop in the housing due to aging of the housing, and current leaks from there, resulting in electric shock. .

(Object 1 of the Invention) The present invention solves the above-mentioned technical problem, and provides an insulating transformer means between an electrical device and a commercial AC power source, and also provides conductive pieces at the openings of the electrical device housing, By electrically connecting these conductive pieces to the
An object of the present invention is to provide an electric shock prevention device for electrical equipment that can prevent electric shock to the human body when the device is immersed in conductive material such as water.

(Structure of the Invention) The present invention provides insulation between electrical equipment as a load and a commercial AC power source! - A lance means is provided, conductive pieces are respectively provided in a plurality of openings formed in the housing of the electrical device, and the conductive pieces are electrically connected to each other.

With this configuration, if the electrical equipment is inadvertently submerged in water, the leakage current through the water will flow through the conductive piece and return to the electric machine, so each opening in the housing will have a conductive piece to completely eliminate the leakage current. The potential is the same, and tm does not flow to the human body outside the housing.

(Example) Fig. 1 is a configuration diagram of a Baird wire in which an electric shock prevention device for an electric appliance according to an embodiment of the present invention is adopted, and Fig. 2 is a plan view of the discharge port metal mesh shown in Fig. 1. Figure 3 (a> is a plan view of the conductive piece near the switch shown in Figure 1, Figure 3 (b)
) is a plan view of the conductive piece near the mounting part shown in FIG. 1, FIG. 4 is a sectional view taken from cutting line IV-IV shown in FIG. 1, and FIG. 5 is an electric circuit including the electric shock prevention device. It is a diagram.

In FIGS. 1 to 5, a power plug 12 includes an insulating transformer means 13 and is connected to a commercial AC power source 11. As shown in FIGS. Commercial literary current 11ff is generated by the isolation transformer means 13.
The 7fJ source isolated from i11 is
It is supplied to the circuit of the dryer main body 15 through. The dryer main body 15 includes a switch 16, a motor 17 and a heater 1 that are controlled by turning on and off the switch 16.
8 is provided. Fan 17 is installed on the shaft of king 17.
When the motor 17 is on and the heater 18 is on, the hot air 11 is sent out from the discharge port 19, respectively.

Furthermore, inside the Dry A7 main body 15, there are a conductive piece 21 made of a metal piece disposed near the attachment part 20 of the power cord 14, and a conductive piece 22 made of a metal piece disposed near the switch 16. It's boiled. The conductive piece 21 has a rectangular shape as shown in FIG. 3(b), and the conductive piece 22 has a ring shape as shown in FIG. 3(a).

A discharge port metal mesh 23 as a mesh-like conductive piece is disposed at the discharge port 19, and a suction port metal mesh 25 is disposed at the suction port 24. Discharge port metal mesh 23
The suction port metal mesh 25, the conductive piece 21, and the conductive piece 22 are electrically connected by the lead wires 26 and 27 and the heater enclosure frame 28.

According to this embodiment, even if the hair dryer main body 15 is immersed in water, the insulation transformer means 13 can prevent electric shock due to ground fault current.

In addition, current flowing through water from the switch 16, motor 17, heater 18, and their connection parts of the hair dryer main body 15 is transmitted through the conductive pieces 21, 22 and the metal mesh 2.
According to 3.25, the housing 1 of the hair dryer main body 15
5a is prevented from leaking to the outside, and therefore, even if the main body 15 of the hair dryer 17 is immersed in water, there is no risk of electric shock. Further, according to the present embodiment, the opening where the switch 16 is formed in the housing 15a and the power source:]
- In places with relatively narrow gaps, such as the opening where the mounting portion 20/'fi of the board 14 is provided, the conductive pieces 22, 21
For places with wide openings such as the discharge port 19 and the suction port 2124 that cannot be blocked as an open flow path, use a metal mesh structure like metal mesh 23.25. By doing, metal mesh 23.25
The current leaking from the gap is small, and all the openings, including the metal meshes 23 and 25, are at the same potential.
No more getting electrocuted. In addition, metal mesh 23.2
5, even if the outer surface is painted, the metal surface is exposed on the inner surface, so the potential will be the same and there will be no electric shock.

In places where the opening is wide and it is necessary to keep the opening open for functional purposes, as in the Beardry 87 shown in this example, the conductor has a mesh structure, so it does not impair functionality. It can also prevent electric shock.

FIG. 6 is an electrical circuit diagram of an inverter circuit showing a first embodiment of the single-stage isolation transformer f shown in FIG.

This inverter circuit A1 includes a rectifier bridge circuit 32 that full-wave rectifies a commercial AC power supply 31, a smoothing capacitor 33 that smoothes the output of this rectifier bridge circuit 32, and a transistor (MO8 type F E-r) that is a switching element. 34, an oscillator 35 that outputs an oscillation signal for switching the transistor 34, and the switching operation of the transistor 34 controls the on/off of 11 currents of the primary coil 36a, and the secondary coil High frequency transformer 36 that generates high frequency induced voltage in 36b
It is equipped with In addition, this inverter circuit Δ1 converts the output from the secondary coil 36b of the high frequency transformer 36 into 7
! ! diodes 37a and 37b to flow the current, and a V slipping coil 38 to smooth the output of the diodes 37a and 37b.
and a \l'ifl capacitor 39.

The outputs of the diodes 37a and 37b smoothed by the smoothing coil 38J3 and the three smoothing capacitors are used as a power source for the hair trie V (main body) 40. In this case, the smoothing coil 38 and the smoothing capacitor 39 may be omitted, and the high frequency pulsating currents output from the diodes 37a and 37b may be supplied to the Ardryre 40 as they are.

The high frequency transformer 36 of the inverter circuit having such a configuration connects the commercial AC power supply 31 and the hair dryer 40.
It will be electrically isolated from the Therefore, even if the hair dryer 40 is immersed in water, there will be no electric shock.

Moreover, by using an inverter circuit as the isolation transformer means, it is possible to achieve a reduction in size and weight compared to an isolation transformer for commercial AC power supply.

FIG. 7 is an electrical circuit diagram of an inverter circuit and a feedback circuit showing a second embodiment of the isolation transformer means of the present invention. In this second embodiment, the output of the inverter circuit A2 is fed back to the input side, and the commercial AC power supply 31 is
00V, 120V.

The circuit is configured so that the output voltage remains constant even if the voltage changes to 240V or the like.

In FIG. 7, components corresponding to those shown in FIG. 6 are given the same reference numerals.

The inverter circuit 2 of this second embodiment includes a rectifier bridge circuit 32, a smoothing capacitor 33, a transistor 34,
High frequency transformer 36, diodes 37a, 37b, smoothing coil 38, three smoothing capacitors, and fuse 4
1.

The feedback circuit 131 includes an output voltage detection circuit 42,
It has an isolator 43 such as a hole to a cover, and a control circuit 44.

The output voltage detection circuit 42 detects the voltage applied to the hair dryer 40 and inputs it to the control circuit 44 through the isolator 43. The control circuit 44 switches the transistor 34 using the output of the built-in oscillator, and controls the switching duty so that the voltage applied to the hair dryer 40 is constant according to the output of the isolator 43. .

With this configuration of the second embodiment, the commercial AC power supply 31
A constant voltage is applied to the hair dryer 40 regardless of changes in the voltage. However, in this second embodiment, the voltage applied to the primary coil 36a of the high-frequency transformer 36 is adjusted so that the voltage applied to the hair dryer 40 does not change even if the voltage of the commercial AC power source 31 changes. There is no need for voltage switching operations such as setting the voltage to a constant value.
Therefore, it becomes possible to switch the own IJ voltage. In addition, the voltage applied to the hair dryer 40 is fed back to the control circuit 44, and in feedback control to keep this voltage constant, an isolator 43 is used to feed back the voltage applied to the hair dryer 40.
0 and the commercial AC power source 31 side are electrically insulated, so that it also functions as an insulating transformer means to prevent electric shock.

Furthermore, when the Hair Dry V40 is dropped into water, various parts of the Hair Dry A740 may become short-circuited and the load current may suddenly flow.
A fuse 41 is provided at fZ, and this fuse 111
By disconnecting, it is possible to prevent the inverter circuit Δ2, the feedback circuit 81, the power cord 14, the hair dryer 40, etc. from being damaged or deteriorating. Note that the fuse 41 may be provided on either the primary side or the secondary side of the high frequency transformer 36. Also,
By providing a current cutoff means that detects the output current and cuts off the output current instead of the fuse 41, the inverter circuit A2, power cord 14, hair dryer 1740
, the feedback circuit 81, etc. can be prevented from being damaged or deteriorated.

In addition, the output current is detected instead of the fuse 41, and when the detected output current exceeds a certain value (a current value above the rated value that does not flow under normal loads), the switching duegay of the transistor 34 is preferentially changed. Even if this output current is suppressed within a predetermined value, the same effect can be achieved by 1
1 will be given.

Note that although the present invention is employed in a hair dryer as an electrical device, it may be employed in other electrical devices.

(Effects of the Invention) As described above, according to the present invention, by providing the isolation transformer means between the electric appliance and the commercial AC power source, the electrical equipment and the commercial AC power source are electrically isolated, Prevents electric shock due to ground fault current when electrical equipment is dropped into water. Moreover, by providing conductive pieces in the openings of the electrical equipment housing and electrically connecting these conductive pieces, each conductive piece has the same potential, thereby preventing the electric shock.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a hair dryer employing an electric shock prevention device for electrical equipment according to an embodiment of the present invention, FIG. 2 is a plan view of the discharge port metal mesh shown in FIG. 1, and FIG. 3 (a> is a plan view of a conductive piece placed near the switch, which is not shown in Figure 1;
FIG. 3(b) is a plan view of the conductive piece placed near the mounting part shown in FIG. 1, and FIG. 4 is a cutting line IV-I not shown in FIG.
5 is an electric circuit diagram of the electric shock prevention device and the hair dryer, and FIG. 6 is an electric circuit diagram of a polyinverter circuit showing the first embodiment of the isolation transformer means shown in FIG. FIG. 7 is an electric circuit diagram of an inverter circuit and a feedback circuit that constitute a second embodiment of the insulating transformer means, and FIG. 8 is an electric circuit diagram for explaining a conventional electric shock prevention device. 13... Insulation transformer means, 15... Hair dryer body (electrical equipment), 15a... Housing, 19...
...Discharge [1 (opening >, 21.22...conductive piece, 2
3...Discharge port metal mesh (mesh-like conductive piece), 2
4... Suction port (listening part), 25... Suction port 1 metal mesh (mesh-like conductive piece), 40... Hair dryer, A1. A2 --- Inverter circuit, B1 --- Feedback circuit. fI revised applicant Matsushita Electric Works Co., Ltd. Representative Patent attorney Etsushi Kotani Patent attorney Chief 1) 1 Patent attorney Yasuo Itaya Figure 2 Figure 3 Figure 4 Figure 7 Figure 8 Figure 2

Claims (1)

[Claims] 1. An insulating transformer is provided between an electrical device as a load and a commercial AC power source, and a conductive piece is provided in each of a plurality of openings formed in the housing of the electrical device. An electric shock prevention device for electrical equipment, characterized in that pieces are electrically connected to each other. 2. Prevention of electric shock in an electric device according to claim 1, wherein the electric device is a hair dryer, and mesh-like conductive pieces are provided at the suction port and the discharge port of the hair dryer. Device. 3. The electric shock prevention device for electrical equipment as set forth in claim 1, wherein the insulating transformer means is constituted by an inverter circuit. 4. The insulating transformer means has a feedback circuit that feeds back the output of the inverter circuit to its input side and sets the output of the inverter circuit to a predetermined value. Electric shock prevention device for electrical equipment.