JPS5814401Y2 - wireless record player - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a wireless record player with a built-in transmitting circuit, and its purpose is to enable the reproduction sound of records to be transmitted without distortion.

In conventional record players, the output terminal of the pickup cartridge had to be connected to an amplifier using a connecting cord in order to hear the record playback sound.

Therefore, no matter how expensive a record player is purchased, the output wiring must be done and is troublesome, and if the wiring is incorrect, it will not be possible to play records correctly.

Moreover, once the wiring was done, it was no longer possible to move the record player freely, and records had to be replaced at the player's location 1 each time.

Furthermore, if you try to hear the sound of a record playing in a room far away from the room where the record player is located (for example, if you place the record player on the second floor and try to hear the sound in a room on the first floor), The volume had to be turned up considerably, which caused a nuisance to others.

Therefore, in the past, it was difficult to freely and easily listen to the playback sound of a record anywhere and while doing anything, which hindered the widespread use of record players.

In order to solve these conventional problems, the present inventor developed a system that transmits the sound of a record as a radio wave and receives and listens to it using a radio receiver or the like.

That is, the record player has a built-in transmitting circuit that converts the output signal of the pickup cartridge into radio waves and transmits them.

According to this, there is no need to do troublesome output wiring work and you can immediately listen to the record playback sound, so the problems of the conventional method can be solved. However, it turned out that there was a flaw that could be called fatal.

That is, when a turntable is rotating while playing a record, thumping noises are mixed into the reproduced sound.

This noise was relatively loud, and especially when playing quiet music, it was extremely harsh and impractical.

Therefore, the inventor conducted research and development with the theme of eliminating this noise, and as a result, found that the above noise could be almost completely eliminated by electrically insulating between the turntable and the turntable support board. .

The inventor of the present invention conjectures that this is due to the following reasons.

That is, in the case of a wireless record player, a transmitting antenna is attached to the Blair cabinet to transmit the output of the pickup cartridge.

Therefore, there is an image ground (virtual ground) for the transmitting antenna.

This image ground is usually represented by the earth, but depending on where the product is placed, the chassis within the product may have a turntable, such as this Weimares record player, and this can be considered an extremely large earth. High frequency current will always flow into the chassis through the shaft with the turntable.

In this case, even if the turntable and the chassis are not coupled in a direct current manner, current flows even if they are coupled with a capacitor.

When the turntable is rotated in such a state, the high frequency current becomes a current that is interrupted depending on the degree of contact of the shaft.

When the transmitting circuit is constructed using the FM system, the frequency modulation circuit, which is one of its components, is not infinitely isolated from the antenna circuit, so a large amount of modulation current flows also in the antenna system, which affects the modulation circuit.

Therefore, the noise due to the intermittent current generated in the shaft portion is reproduced from the speaker through the system system of modulation transmission → reception → demodulation.

Therefore, it seems that the noise was eliminated by completely cutting off the high frequency current flowing from the turntable to the chassis.

Next, one embodiment of the present invention will be explained using a drawing showing a belt-driven coat player.

As shown in the figure, 1 is a synthetic resin Blair cabinet;
Reference numeral 2 denotes a bottom cover also made of synthetic resin, and this bottom cover 2 is attached to the player cabinet, and the two constitute a cabinet body.

3 is a vibration-absorbing insulator attached to the bottom cover 2, and 4 is a metal chassis fixed with screws 6 to a boss 5 integrally provided on the bottom of the player cabinet 1. A drive plate 8 and the like are attached to which the large gear 1 for driving the mechanism reciprocates in response to the rotational force of the large gear 7.

9 is the turntable for setting the record, 10 is its rotating shaft, 11 is the pink-up cartridge, 1
2 is a tone arm, and 13 is a rotation bearing for the tone arm.

Reference numeral 14 denotes an FM stereo transmitting circuit that stereo-modulates the left channel output signal R and the right channel output signal R from the pickup cartridge 11 and transmits them as FM radio waves.
Reference numeral 5 denotes a transmitting antenna for radiating the output high-frequency signal from the transmitting circuit 14, and this antenna 15 is fixedly attached to the rear edge of the upper surface of the player cabinet 1.

16 indicates a dust cover. Next, the structure between the turntable 9 and the chassis 4 that supports it will be explained.

Since the turntable 9 is made of metal and its shaft 10 is also made of metal, a tapered portion IT made of synthetic resin is provided in the groove portion 10a provided on the upper outer periphery of the shaft 10 in order to eliminate electrical continuity between the grooves. The center taper hole of the turntable 9 is fitted into the taper portion 17 of the turntable 9.

Note that the reference numeral 18 placed on the turntable 9 is a rubber sheet, and the turntable 9 and the shaft 10 are not electrically connected to each other by this rubber sheet.

A small gear 19 that meshes with the large gear 7 is integrally provided at the lower end of the tapered portion 17 .

Furthermore, a bearing 20 that rotatably supports the rotating shaft 10 is also made of synthetic resin and is fixedly attached to the chassis 4.

A metal cylinder 21 is embedded in the bearing 20, taking into consideration that resin alone causes a large amount of wear.
so that the shaft 10 is received.

As described above, in this embodiment, the tapered portion 17 and the bearing 20 are made of synthetic resin, and the turntable 9 and the chassis 4 are electrically insulated, so that the high frequency signal from the antenna 15 is transmitted to the turntable 9. from the shaft 10 to the chassis 4, and therefore the shaft 1
As the zero rotates, the flow condition changes and there is no noise.

In this case, since the turntable 9 is completely floating, static electricity may accumulate as the record is played, and this may suddenly discharge and cause noise. If conductive powder is mixed into the resin to be formed and the resistance value is controlled to a value of several MQ that does not damage the insulating metal, only static electricity will be discharged to the chassis 4 side, and noise generation will be eliminated.

The tapered portion 17 can be easily formed by a molding method in which the shaft 10 is placed in a mold and resin is injected, so-called insert molding.

The same applies to the bearing 20 and the cylindrical metal 21.

In the player of this embodiment, the motor that drives the turntable via a belt is operated by a battery built into the cabinet.

As explained above, according to the wireless record player of the present invention, there is no need for troublesome wiring work between the record player and its playback amplifier system, and it is possible to immediately listen to and enjoy the playback sound of the record. Moreover, since there is no need for wiring as described above, there is no problem of incorrect reproduction of sound due to wiring errors.

In addition, since the record player can be used freely separated from the reproduction amplification system, the user can easily perform record changing operations while keeping the player at hand.

If a portable receiver or the like is used as a playback amplification system for a player with a housing, the user can enjoy the playback sound of a record at a location of his/her preference even if the player is placed in a predetermined position.

Furthermore, since the transmitting circuit section is built into the same casing that constitutes the player, the relatively large space inside the casing of the player can be used effectively, and wiring connections can be simplified.

Moreover, the simple structure of insulating between the turntable and the substrate such as the chassis that supports it can prevent the generation of noise caused by the rotation of the turntable, making it possible to provide a record player with excellent characteristics at a low cost. .

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a wireless record player according to an embodiment of the present invention, FIG. 2 is a sectional view of a rotating shaft of the player, and FIG. 3 is a sectional view of a bearing thereof. 4...Chassis, 9...Turntable, 11...Pickup cartridge, 14
...FM stereo transmission circuit, 15...
Transmission antenna, 1T...Synthetic resin taper part,
20...Synthetic resin bearing.

Claims (1)

[Scope of utility model registration request] A record player comprising a transmitting circuit for transmitting an output signal from a pickup cartridge in the form of radio waves and a transmitting antenna for radiating the output signal from the transmitting circuit, the turntable and the turntable support substrate; A wireless record player characterized by electrically insulating the space between the record players.