JPH0498721A - Switch with display lamp - Google Patents

Abstract

PURPOSE:To reduce a variation in luminance of a display element according to a load current and make a failure difficult to happen even in the case of flowing of a surge current by connecting light emitting diodes between the input and output terminals of a rectifier block via a choke coil. CONSTITUTION:A switch main body A is interposed between a power source V and a load L. When a switch portion SW is turned on, a current in the direction indicated by a solid line and a current in the direction indicated by a broken line are alternately supplied because of AC power sources of diodes D1-D5 in bridge connection. A constant potential difference is always generated between points (a) and (b). Luminance of light emitting diodes LED1, LED2 is not largely changed, thus keeping nearly constant luminance. A rush current and a surge current are difficult to pass through a choke coil L1. However, energization to the diodes LED1, LED2 is not prevented with respect to a normal current. The insertion of the coil L1 enables stable currents of the diodes LED1, LED2 to be supplied. Therefore, effects are attainable including that a variation in luminance of the light emitting diodes is small and that an accident is difficult to happen.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a switch with an indicator light that allows confirmation of the operating state of a load.

[Prior Art] Conventionally, in this type of switch with an indicator light, a current transformer is inserted and connected to the main circuit, an output is obtained from the secondary side of the current transformer according to the magnitude of the load current, and the output is [Problem to be Solved by the Invention] In such a conventional example, the manufacturing cost is high because a current transformer is used, and the current transformer has a problem in that the secondary current changes depending on the magnitude of the primary current. Because of the difference, there was a problem in that the brightness of the display element changed. Furthermore, there is a problem in that the display element is likely to fail when a surge current flows through the primary side of the current transformer.

The present invention has been provided in view of the above-mentioned points, and an object of the present invention is to reduce the change in brightness of a display element due to the magnitude of load current, and to make it less likely to fail even when a surge current flows. The present invention provides a switch with an indicator light.

[Means for Solving the Problems] The present invention connects diodes in a bridge shape, and
A rectifier block with a diode connected between the midpoints of each side, a display block with a light emitting diode connected between the input and output terminals of the rectifier block via a choke coil, and a switch section not connected in series with the display block. It is equipped with the following.

[Function] Therefore, the voltage drop of the rectifier block is used to light the light emitting diode of the display block with a small change in brightness, and the light emitting diode is equipped with a choke coil to block surge current. Therefore, it is affected by surge current.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure shows a circuit diagram of the switch main body A, and its electrical circuit configuration includes a rectifier block 1, a display block 2, and a switch section SW of an opening/closing mechanism section. The rectifier block 1 has diodes D1 to D4 connected in a bridge shape, and further connects the anode of the diode D to the connection point between the canards of the diode D1, and connects the anode of the diode D,
The 5-display block 2, whose cathode is connected to the connection point between the anodes of diodes D2 and Ds, is composed of two light emitting diodes LED, , LED, connected in parallel in opposite directions, and a choke coil L1.

The display block 2 is connected to the input and output terminals of the rectifier block 1.

The switch main body A is interposed between a power source V and a load. Now, when the switch part SW is on, the diodes D1 to D are AC power sources, so the current in the direction of the solid line and the current in the direction of the broken line alternately flow. That is, in the positive half cycle of the AC power supply, as shown by the solid arrow, the diode D1→D.

A current flows from -+-D3 to the load, and in the negative half cycle, current flows from the load L to the diode D, and from D5 to D2. Since the voltage drop across the diodes D, .about.D is substantially constant without being affected much by the magnitude of the load current, a constant potential difference always occurs between a and b. Therefore,
This potential difference between a and b is the light emitting diode LED, LE
Since a substantially constant current is supplied to D2, the brightness of the light emitting diodes LED does not change much and remains almost constant.

Here, the forward voltage drop per diode is
The voltage is about 0.7V. In addition, the forward voltage drop of a light emitting diode is, for example, in the case of a gallium-phosphide device,
It is about 18V, and in the case of gallium aluminum arsenic element it is about 15V, so the light emitting diode LED,...
In order to cause current to flow through LED2, three diodes are required to be connected in series. In the present invention, when diodes D, .

However, when a series circuit of three diodes is connected in parallel as shown in FIG. 2, a total of six diodes are required to light a light emitting diode. That is, by connecting as shown in FIG. 1 of the present invention, the number of diodes can be reduced by one.

By the way, in the case of a switch with a built-in conductor, the element may fail due to factors such as inrush current when the power is turned on, induced lightning surges induced in the power line, and electrostatic discharge that a person receives when operating it, resulting in non-conductivity. There are possible cases.

Figure 3 shows the current waveforms of the diodes D, ~D5 in the circuit of Figure 1, where (a) shows the load current, and (b) shows the currents of the diodes D, D, and D5. (e) is the diode D2. The figure (d) shows the current of D3 and the current of diode D, respectively. Diode D.

Compared to the other diodes D1 to D4, in which current flows only in one half cycle, current flows in both half cycles, so there is a high probability that diode D will fail and become non-conductive. When the diode D becomes non-conductive, the entire rectifier block 1 becomes non-conductive, and the load current is transferred to the display block 2.
Everything will flow to. This means that if the load current is within the ratings of the light emitting diodes LED1+LED2, switch body A can be used without any problem, but if it exceeds the ratings, the light emitting diodes LED, LED2 will fail and switch body A will become non-conducting. Become.

In this respect, the above-mentioned No. 21! simply connects a plurality of diodes in series and parallel! In the case of a circuit as shown in I, the diode D1~
The probability that all D, will fail is constant, and if diode D1 fails and the load @ current is light emitting diode L
ED,, above the rating of LED2, light emitting diode LED
,, If LED2 fails, a half-wave rectified current as shown by the broken line will flow through the circuit. Incidentally, since the rated current of a light emitting diode is as small as several tens of mA, the load current is usually higher than the rated current.

This situation is dangerous because it will adversely affect the load and, in the worst case, may cause failure or burnout of the load. However, with the circuit configuration shown in FIG. 1 of the present invention, there is a high probability that the entire switch body A becomes non-conductive, as described above, and failure occurs in a safe mode.

FIG. 4 compares the load current and brightness of the light emitting diode between the switch body A of the present invention and a conventional switch with a built-in current transformer. As is clear from FIG. 4, the change in brightness of the switch body A of the present invention is smaller than that of the current transformer type, regardless of the magnitude of the load current.

Next, the light emitting diodes LED+, LED
The role of the choke coil L1 connected in series to 2 will be explained. As mentioned above, when an inrush current or surge current flows into a load circuit, these currents naturally flow in a divided manner to the rectifier block 1 and display block 2, but the rectifier diodes D, ~D, light emitting diode LE
Although D,, has relatively excellent durability compared to LED2, the light emitting diode LED,, LED Dz is very weak, and even if the diode D, ~D, is intact, the light emitting diode LED,,,
There is a possibility that only LED2 fails.

Rush currents and surge currents have very high peak values, but pulse widths are very short, ranging from several μSees to several 111 Sees.
Since the amount of current change Ai/Δt per unit time is very large, it is difficult for the current to pass through the choke coil L. If the choke coil L1 protects the light emitting diodes LED, LED2, the light emitting diodes LED, LED will experience inrush current and surge. It is less susceptible to the influence of current, so it is less likely to fail. In addition, since the impedance is not so large for a steady current, the choke coil L is
5 light emitting diodes LED by inserting 1, L
A stable current supply to ED2 can be realized.

Next, the specific structure of the switch body A will be explained with reference to FIGS. 5 to 8. The outer shell of the switch main body A is composed of a body 4 and a cover 5, and terminal portions 6 are formed on both sides of the body 4 to be connected to electric wires from the outside. The terminal section 6 is composed of a substantially U-shaped terminal plate 7, a substantially S-shaped locking spring 8 for press-connecting the conductor of the electric wire to the terminal plate 7, and a release button 9 for releasing the electric wire. There is. The bottom of the body 4 is provided with a wire insertion hole 10 through which an electric wire is inserted, and a release hole 11 into which the tip of a screwdriver or the like is inserted to press the release button 9 into contact.

A rib 12 made of an insulating material is integrally protruded approximately at the center of the body 4, and a storage portion 13.1 is formed with the rib 12 as a border.
4 is formed. An opening/closing mechanism section is stored in one of the storage sections 13. That is, the support plate 15 electrically connected to one terminal plate 7 is arranged at the bottom of the storage section 13,
A substantially U-shaped opening/closing body 1 is mounted on a protrusion 16 formed on the support plate 15.
7 are arranged so as to be swingable. A movable contact 18 is fixed to one side of the opening/closing body 17, and a fixed contact 19 facing the movable contact 18 is provided on the other terminal plate 6.

A handle 21 is provided in the opening 20 of the cover 5, and the lower surface of the actuator 22 protruding from the lower surface of the handle 21 comes into contact with the upper end of the opening/closing body 17, and the seesaw movement of the handle 21 causes the opening/closing body 17 to open and close. Operate the seesaw and contact 18
．． It is designed to open and close 19 times. Furthermore, this contact point 1
8.19 constitutes the switch section SW shown in FIG.

Inside the other storage section 14, a diode D of the rectifier block 1 is placed.
1 to D and a printed circuit board 23 on which the choke coil L1 is mounted. Further, the display body 24 in which the light emitting diodes LEDs of the display block 2 are integrated, is mounted on another printed circuit board 25, and this printed circuit board 25
is fixed to the lower surface of the handle 21. Both printed circuit boards 23 and 25 are connected by a lead wire 26. Here, the printed circuit boards 23 and 25 have grooves 27 and 27, respectively.
, 28 are formed, and the soldering ends of the lead wire 26 are slightly slackened from the parts, and the lead wire 26 is connected to the ends 27, 28.
It is fixed at This means that even if the handle 21 is reversed,
The purpose of soldering the lead wires 26 is to prevent parts from being disconnected. Further, the printed circuit board 23 and the terminal board 7 are also connected by lead wires 29.

Display body 24 of printed circuit board 25 fixed to handle 21
The upper surface of the handle 21 is located in correspondence with the display hole 30 of the handle 21, so that the load state can be visually confirmed from the outside of the handle 21.

Here, the switch main body A of the present invention is formed to have the size of one standardized wiring device module, and is configured to be detachably attached to a standardized mounting frame. On both sides of the cover 5, locking claws 31 for attachment to the mounting frame are provided to protrude laterally.

Figure 9 shows a plate frame 32 to which the switch body A is mounted.
This is an exploded perspective view when installing the second root frame 3.
2 is large enough to mount three switch bodies A each having the size of a standardized wiring device module 1fi1.

The body 4 and cover 5 of the switch main body A are the assembly frame 3.
3, and the above-mentioned locking pawl 31 is formed on this assembly frame 33. A pair of locking holes 34 are formed in one side piece of the plate frame 32, into which a pair of locking claws 31 on one side of the switch body A are inserted and locked. Further, a flexible piece 35 that can be bent laterally is integrally formed on the other side piece of the plate frame 32, and the other pair of the switch body A is engaged with a pair of locking portions of this flexible piece 35. The claw 31 is inserted and locked, and the switch body A is detachably mounted on the plate frame 32. Further, the plate frame 32 is provided with a mounting hole 36 for inserting a screw for mounting to a switch box buried in a wall surface.

A decorative plate 37 is attached to the front surface of the plate frame 32, and an engaging claw 38 is protruded from the back surface, and by fitting the engaging claw 38 into the engaging hole 39 of the plate frame 32, , a decorative plate 37 is detachably attached to the plate frame 32. The decorative plate 37 also includes a switch body A.
An opening 40 is bored through which the handle 21 of the handle 21 is exposed.

[Effect of the invention 1] As described above, the present invention includes a rectifier block in which diodes are connected in a bridge shape, and diodes are connected between the midpoints of each side, and a light emitting diode is connected between the input and output terminals of this rectifier block. Since it is equipped with a display block connected via a choke coil and a switch section connected in series with the display block, the voltage drop of the rectifier block is used to change the brightness of the light emitting diode of the display block. By making the light smaller and lighting it, it can be manufactured at a lower cost compared to the conventional method that uses a current transformer.Moreover, since the light emitting diode is lit using the voltage drop of the diode, the light emitting diode Changes in brightness are small, and the light emitting diode uses a choke coil to block surge current, making it less susceptible to surge current, so even if surge current flows through the load circuit, it will not emit light. This has the effect that excessive current does not easily flow through the diode, making it less likely to break down.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the same as above, Fig. 3 is an operation waveform diagram of the same as above, and Fig. 4 is a characteristic showing the load current and brightness of the light emitting diode as above. Figure 5 is a sectional view of the switch body as above, Figure 6 is a planar opening with the cover removed, Figure 7 is a perspective view of the main parts of the same as above, Figure 8 is
The figure is a front view of the main parts of the same as above, and FIG. 9 is an exploded perspective view showing the construction state of the same. 1 is a rectifier block, 2 is a display block, and D. ~D, is a diode, LED+, LED
2 is a light emitting diode, and SW is a switch section. Agent Patent Attorney Ishi 1) Long 71... Rectification Pro N. 2... Display Block Figure 3

Claims (1)

[Claims] (1) A rectifier block in which diodes are connected in a bridge shape and the midpoints of each side are connected by diodes, and a display block in which a light emitting diode is connected between the input and output terminals of this rectifier block via a choke coil. , a switch with an indicator light, which includes an indicator block and a switch part connected in series.