JPS6412001B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a linear tracking type record player. In general, a linear tracking arm device that traces a tone arm in a tangential direction with respect to the sound groove of a record disc without any error has a support rod 8 and an auxiliary guide plate 9 as shown in FIGS. 1 and 2. The tone arm 6 is moved by the support rod 8 and the auxiliary guide plate 9.
was attached directly to the inner surface of the cabinet lid 1. 3 is a turntable, 4 is its drive motor, and 5 is a support rubber. 10 is tone arm 6
11 is a transmission gear, 12 is a transmission wire, and 7 is a reproduction head. All of these are directly attached to the cabinet cover 1, and the arm support rod 8 and auxiliary guide plate 9 are also attached to the cabinet cover 1. In a linear tracking arm device having such a structure, the acoustic output from the speaker causes the cabinet cover 1 and the cabinet body 2 to resonate, and the unnecessary vibrations are transmitted to the tone arm 6, causing howling and changing the acoustic characteristics. The disadvantage was that it worsened the In order to prevent this, it has been proposed that the support rod 8, auxiliary guide plate 9, etc. are independently installed in a floating state using an elastic body such as rubber, and this has a considerable vibration-proofing effect. can get. However, sufficient vibration-proofing effects have not yet been achieved, and each individual component must be attached via an elastic member, which increases man-hours and makes it difficult to obtain dimensional accuracy for the motor and drive mechanism, resulting in poor reliability and There was a problem with lack of stability. Therefore, an object of the present invention is to provide a record that prevents vibrations from the cabinet from being transmitted to the tone arm housed inside the cabinet, has excellent acoustic characteristics, requires fewer assembly steps, and has excellent reliability and stability. The goal is to provide a player. An embodiment of this invention is shown in FIGS. 3 to 5. That is, in this record player, a base body 13 is fixed to the back surface of the cabinet lid body 1 through four cylindrical elastic bodies 15 in a floating state with screws 16, and a guide member of the tone arm 6' is attached to the base body 13. A supporting rod 8' and an auxiliary guide plate 9' are integrally attached, and a motor 1 serving as an arm driving device is installed.
0', gear 11' and wire 12' pulley 17
is installed on the base body 13. The screw 16 is inserted into the mounting hole 14 of the base body 13. The base body 13 is made of a press-molded product of iron or stainless steel. The elastic body 15 is made of rubber or the like. The tone arm 6' has a reproduction head 7' at its tip, and is supported movably in the radial direction of the turntable 3 by a support rod 8' and an auxiliary guide plate 9'. Further, the tone arm 6' is connected to a wire 12' and driven by the rotation of a motor 10' via a gear 11' and a wire 12'. In this way, all the members for supporting and driving the tone arm 6' are attached to the base body 13, and this base body 13 is attached to the cabinet lid body 1 via the elastic body 15, so that the cabinet 1,
2 resonance is not transmitted to the tone arm 6', and an excellent acoustic effect can be obtained. In addition, unlike the method in which each individual component is installed via an elastic body, only the base 13 to which each component is attached is attached to the cabinet lid 1 via the elastic body 15, so the number of man-hours is reduced. , it is easy to achieve mutual dimensional accuracy between parts, and excellent reliability and stability can be obtained. By forming the base body 13 by press working as described above, even more reliable dimensional accuracy can be obtained. FIG. 6 shows the vibration isolation effect of this embodiment. FIG. 6A shows that resonances ₁ , ₂ , and ₃ are present in the cabinet body 2. In this case, if _the resonance frequency _of the base ₁₃ is set to ₀ ( ₀ < ₁ ) as shown in FIG. FIG. 7 is a comparison diagram of the pickup output characteristics of the record player of this embodiment, where A shows the conventional type and B shows the case where the base body 13 of this embodiment is floated by an elastic body 15 made of rubber. In this way, the acoustic characteristics were improved. Next, the vibration characteristics of this example will be theoretically considered. This record player can be analogized to the equivalent circuit shown in FIG. In the figure, V〓 ₀ : Vibration velocity of the cabinet lid body 1 [m/s] C ₁ : Compliance of the elastic body 14 [m/N] R ₁ : Resistance of the elastic body 14 [Nsec/m] m ₁ : Base body Mass of 13 [Kg] (Including tone arm, support rod, auxiliary guide plate, arm drive device, etc.) C ₂ : Compliance of cartridge 7' [m/
N〕 R ₂ : Resistance of cartridge 7' [Nsec/m] m ₂ : Effective mass of cartridge 7' [Kg] V〓 : Vibration speed of cartridge 7' [m/s] In the equivalent circuit of Fig. 8, m ₁ 》m ₂ ≒0, the speed ratio V〓 ₀ /V〓 is given by the following formula. However, X=jω/ω ₀ ,

【formula】

[Equation] The transfer function of the above equation is as shown in FIG. 9, and the resonance frequency ₀ of the system of the base mass and the elastic body is expressed by the following equation. Therefore, when the resonance frequency ₀ is selected which is sufficiently lower than the frequency of the cabinet cover 1, the vibration of the cabinet base 1 is not transmitted to the tone arm 6', which proves that the vibration isolation effect is excellent. can. As described above, in the record player of the present invention, the guide member and drive mechanism of the tone arm are attached to the base body, this base body is attached to the cabinet lid body via an elastic body in a floating state, and the base body including the tone arm etc. Since the resonance frequency is sufficiently lower than the vibration frequency of the cabinet lid, the vibration of the cabinet is not transmitted to the tone arm, resulting in excellent acoustic characteristics, less assembly time, and excellent reliability and stability. This has the effect that it can be obtained.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional record player, Fig. 2 is a partial plan view thereof, Fig. 3 is a sectional view of an embodiment of the present invention, Fig. 4 is a partially enlarged plan view thereof, and Fig. 5 is the same. 6 is an explanatory diagram showing the vibration isolation effect, FIG. 7 is a comparison diagram of the pickup output characteristics, FIG. 8 is an equivalent circuit diagram of the vibration system of the same example, and FIG. 9 is a partially enlarged sectional view of the same. is an explanatory diagram showing the transfer characteristics of an equivalent circuit. DESCRIPTION OF SYMBOLS 1... Cabinet lid body, 2... Cabinet body, 3... Turntable, 6'... Tone arm, 8... Support rod (guide member), 9... Auxiliary guide plate (guide member), 10... Motor (arm drive mechanism), 13...base body, 15...elastic body.

Claims (1)

[Claims] 1. A cabinet body on which a turntable is installed, a cabinet lid facing the cabinet body, a tone arm movable in the radial direction of the turntable, a support rod and an auxiliary member that are guide members for the tone arm. It is composed of a guide plate, an arm drive mechanism for moving the tone arm, the support rod, and a base body on which the auxiliary guide plate is installed, and an elastic body is interposed between the cabinet lid body and the base body. A record characterized in that a base body is mounted in a floating state with respect to the cabinet cover body, and the resonance frequency of the base body including each component installed on the base body is set to be sufficiently lower than the vibration frequency of the cabinet cover body. player.