JPS6320200Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a switching circuit between a speaker of an external handset and a speaker (or microphone) of the main body of a portable radio to which an external handset can be connected.

Traditionally, portable radios have been used in two ways: holding the main body of the radio in the hand to make calls, and with radios equipped with an external handset, the main body of the radio is attached to the waist of the human body and only the external handset is held in the hand. There are times when you hold the phone while making a call. Traditionally, radios that use an external handset did not have a built-in speaker in the main body of the radio, but recently, with the diversification of uses, it is now possible to have a speaker built into the main body of the radio and use an external transmitter. It has become necessary to also be able to connect a telephone receiver. In this case, since the external handset also has a built-in speaker, the first speaker inside the radio and the second speaker on the external handset are connected in parallel or in series as an audio circuit. When the speakers are connected in parallel, the current consumption increases, and when they are connected in series, the sound pressure at each speaker is decreased.
This has the disadvantage of reducing the overall efficiency of the audio system. Furthermore, when a speaker is used as a microphone, there is a drawback that noise other than the call may be mixed in from other speakers that are not involved in the call.
Therefore, when an external handset is connected, it is necessary to stop the function of the main body's speaker.

One structure to achieve this is to insert a mechanical switch into the speaker circuit of the radio device itself. However, with this structure, the switch must be mounted by drilling a hole in a separate location in the housing, so for applications that require waterproofness, both the mounting hole and the switch itself must be waterproof. , the company could not avoid the factor of cost increase. Another structure is to use a relay or semiconductor switch to disconnect the speaker line on the main body side. These have an advantage over mechanical switches in terms of waterproofness, but when using relays, the mounting space for the relay must be secured, and the excitation current of the coil is approximately 10%.
It required ~20mA, making it unusable for portable radios. In addition, compared to mechanical switches or relay contacts, which have a contact resistance of 10 mΩ or less, semiconductor switches have a large connection resistance of about 10 to 100 Ω, and the speaker voice coil has a low impedance of 4 to 16 Ω. As a circuit switch, it suffers from large losses, so it cannot be used in applications such as portable radios where the necessary output cannot be obtained even when the power supply voltage is fully utilized.

Therefore, the purpose of the present invention is to eliminate the drawbacks of the conventional structure, and also to prevent the built-in speaker or microphone from being disconnected from the audio circuit by the way it is attached to the mounting bracket of the portable radio device. An object of the present invention is to provide a speaker microphone switching device that controls the speaker microphone switching device.

According to the present invention, a portable radio device main body has a built-in speaker or microphone and a switch for disconnecting the audio circuit for the speaker or microphone;
a mounting means for mounting the main body, and when the main body is mounted on the mounting means with the front surface of the built-in speaker or microphone facing outward to the mounting means, the switch is closed or opened, and There is obtained a switching device for a speaker microphone of a portable radio device, characterized in that the switch is arranged so that the circuit is open or closed when the device is mounted in the opposite direction.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram of a conventional speaker switching device. The audio output circuit 1 reproduces and outputs an audio signal from a wireless signal received by a receiving section (not shown) of a portable wireless device. An external handset 11 including a speaker 7 (which may function as a microphone in some cases) is connected to the audio output circuit 1 in parallel with the speaker 3 via a jack 6 . In order to block the sound from the speaker attached to the main body 10 of the radio, the circuit of the speaker 3 is realized as an open loop by operating a mechanical switch 31 provided in series with the speaker 3. In the figure, reference numeral 2 is a DC blocking capacitor, and 4 and 8 are voice coils of speakers 3 and 7, respectively.

FIG. 2 is a schematic diagram of a conventional speaker switching device. Relay switches 32 and 33 are inserted in place of the mechanical switch 31 shown in FIG.

The conventional speaker switching devices shown in FIGS. 1 and 2 have the drawbacks mentioned above.

FIG. 3 is a schematic diagram of an embodiment of a speaker switching device for a portable wireless device according to the present invention. The output terminal of the audio output circuit 1 is connected to the voice coil 4 of the speaker 3 on the radio main body side 10 via a DC blocking capacitor 2, and to an external signal via a reed switch 5 and an external plug 6 connected in series. External speaker 7 in speaker 11
are connected. Now, when the reed switch 5 is closed, the voice coils 4 and 8 of the speakers 3 and 7 are connected in parallel, and the load impedance becomes 1/2, so the load 4 A total of about twice as much current will flow through 8 and 8. In this state, sound will be output from the two speakers 3 and 7 at the same time.
In general, even if a radio device worn on the waist emits sound, the distance from the user's ears is far away, so the sound pressure decreases and it is not a practical sound source in places with a lot of external noise. Since only the handset contributes to the transmission of information, the overall efficiency is reduced in this case. Therefore, when using the external handset 11, the main body of the radio device is generally housed in a fitting attached to the waist of the human body, and the magnet 21 is mounted on this device fitting so that the reed switch 5 of the main body 10 is connected to the magnet 22. The normally closed contact formed by magnetization is arranged so as to open depending on the strength of the magnetic field when the magnet 21 is brought close to the speaker 3.
turn off. Here, the following methods can be considered as ways of arranging the main body of the radio with respect to the equipment fitting. In other words, if the radio is mounted on a metal fitting so that the front of the built-in speaker 3 faces outward from the human body, the reed switch 5 will be closed, and if it is mounted facing inwards, the reed switch 5 will be opened. That's what I do.

As is well known, a reed switch is a device in which two opposing leads of two ferromagnetic materials are magnetized by applying an axial magnetic field to one free end of the leads from the outside, and the free ends attract each other and come into contact with each other. .
For this reason, the main body is enclosed in a glass tube and isolated from the outside air, and it is connected to the control magnet only through a magnetic circuit, making it ideal for a switch that requires waterproofness. In addition, no current is required to control the switch, and
The space it occupies is about the same as that of a general resistor, which is sufficient for use in portable radio equipment. Furthermore, due to the fact that it is used in large quantities in switching equipment and small precision machines,
The price is low, and the reliability and strength are perfect for practical use.
It is ideal for use in the applications required by the present invention. Although the present invention has been explained using an example of a reed switch having a normally open contact and two magnets, the present invention can use any magnetic switch circuit formed between a radio and a mounting bracket.
Furthermore, various applications can be considered regarding the type of reed switch, the number of magnets, and the configuration of the magnetic shield circuit. Furthermore, although the embodiment shown in FIG. 3 is shown only for receiving calls, the present invention can also be applied to press-to-talk type radios if the radio has a built-in transmitter and speakers 3 and 7 are used together with the microphone. You can use it.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams of a conventional speaker switching device for a portable wireless device, and FIG. 3 is a schematic diagram of an embodiment of the present invention. In the figure, 10...Portable radio device body, 11...External receiver, 1...Audio output circuit, 2...DC blocking capacitor, 3...Speaker inside the portable radio device body, 4...Voice coil of speaker 3, 5...Reed switch, 6...External connector, 7...Speaker for external receiver, 8...Voice coil of speaker 7, 21...Magnet inside the equipment fitting, 22...Magnet inside the radio body, 31...
...Mechanical switch, 32...Relay contact, 33...
...It's a relay.

Claims (1)

[Scope of utility model registration request] It consists of a portable radio main body having a built-in speaker or microphone and a switch for disconnecting and disconnecting an audio circuit for the speaker or microphone, and a mounting means for mounting this main body, and the main body is attached to the mounting means. The mounting means is configured such that the switch is closed or open when the built-in speaker or microphone is mounted with the front surface facing outward on the mounting means, and the switch is opened or closed when the built-in speaker or microphone is mounted with the front face facing outward. 1. A speaker microphone switching device for a portable radio device, characterized in that a means for controlling connection/disconnection of the switch provided therein and the switch are arranged in relation to each other.