JPS5853428B2 - Tone arm drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tone arm drive device for a record player.

The tone arm is desired to be easily operable with a minute driving force, that is, to be highly sensitive, in order to move the stylus of the cartridge to follow the sound groove of the record without resistance.

Conventionally, the mechanism of the rotating part of a tone arm includes bearings,
A method was adopted in which the rotating shaft was supported by means such as a knife or pinpoint.

However, in such a structure, there is frictional resistance associated with the rotation of the rotating shaft, and it does not operate at all with a driving force less than the maximum static frictional force, making it difficult to obtain sensitivity above a predetermined value. .

Therefore, in order to reduce the frictional resistance and obtain a highly sensitive tone arm, methods such as using a jewel in the bearing or increasing the arm length have been adopted, but the former is extremely expensive and It has the disadvantage of being easily damaged, and the latter has the disadvantage of increasing its effective mass.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tone arm drive device that has high sensitivity regardless of the configuration of the bearing mechanism, in order to eliminate the above-mentioned drawbacks.

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

FIG. 1 is a side view of a tone arm drive device according to the present invention applied to an offset arm, and FIG. 2 is a partial plan view of FIG. 1.

In the figure, a tone arm 1 is rotatably supported by a holder 2 in the vertical direction.

One end of an elastic member 3 such as a plate spring is fixed to this holder 2 .

The other end of the elastic member 3 is held by a holding part 6 of a rotating means 7 consisting of a gear 5 rotatably held by a support shaft 4 and a holding part 6 interlocked with the gear.

This gear 5 is rotationally driven by a driving means 10 consisting of a motor 8 and a worm 9 fixed to the rotating shaft of the motor and engaged with the gear.

The rotating means 7 is not limited to the gear 6 that engages with the worm 9, but may be any means that can hold the elastic member 3 and be rotationally driven by the motor 8.

The driving means 10 is controlled by a displacement detecting means for detecting the displacement of the tone arm 1 with respect to the rotating means 7, for example, a control means 12 which is fixed to the elastic member 3 and receives a detection signal from a strain gauge 11 which detects this strain. Ru.

The displacement detection means may be an optical system comprising a light emitting element, a light receiving element, and a mirror provided on the tone arm to reflect the light from the light emitting element to the light receiving element.

Note that 13 is a spring for preventing loose fludge.

Further, a head shell 15 having a cartridge 14 and a counterweight 16 are disposed at the tip and rear ends of the tone arm 1, respectively.

Next, the operation of the tone arm drive device configured as described above will be explained.

The tone arm 1 is configured so that the stylus tip of the cartridge 14 follows the sound groove of a record (not shown), so that the elastic member 3
is distorted and deformed, for example, by an angle θ, as shown in FIG. 3a.

When the elastic member 3 is distorted, the strain gauge 11 detects this distortion and supplies a detection signal to the control means 12.

The control means 12 rotates the motor 8 in response to this input signal.

As the motor 8 rotates, the gear 5 engaged with the worm 9 rotates by an angle θ, thereby making the strain in the elastic member 3 zero, as shown in FIG.

By repeating these operations, the stylus tip of the cartridge 14 moves without resistance, following the sound groove of the record.

At the end of the performance or when the performance is being performed, there is a means to detect this (
The control means 12 drives the motor 8 in response to a signal from a tone arm (not shown) to rotate the gear 5 in the opposite direction to the above-mentioned direction and return the tone arm 1 to the armrest (not shown).

As described above, since the drive device according to the present invention uses the elastic member 3 such as a leaf spring, it can operate even with an extremely small force, unlike bearings and the like that operate only on a fixed force plate.

Also, a strain gauge 11 for detecting strain in the elastic member 3
By increasing the gain of the control means 12 and increasing the response speed, the angle θ shown in FIG. 3a can be made extremely small, and a highly sensitive drive device can be obtained.

Although the above embodiment is applied to an offset arm, it is also possible to use a slidable sliding means instead of the rotating means 7 to provide a driving device for a linear tracking arm.

As described above, according to the tone arm driving device according to the present invention, the tone arm can be easily operated with a minute driving force.

In addition, high-precision parts are not required, and especially when used in record players with automatic functions, the same motor can automatically start and stop the performance without using a separate motor, and furthermore, the tone arm can be freely used while playing. Since no complicated latch mechanism is required for this purpose, the cost is extremely low.

[Brief explanation of the drawing]

FIG. 1 is a side view of a tone arm drive device according to the present invention applied to an offset arm, FIG. 2 is a partial plan view of FIG. 1, and FIG. 3 is a schematic plan view showing the operation of the tone arm drive device according to the present invention. It is a diagram. Explanation of symbols of main parts, 1... Tone arm,
2...Holder, 3...Elastic member, 5
... Gear, 7 ... Rotating means, 8 ...
Motor, 9...Worm, 10...Driving means, 11...Strain gauge, 12...
...control means.

Claims (1)

[Scope of Claims] 1. A holder that rotatably supports a tone arm vertically; an elastic member having one end fixed to the holder;
a rotating or sliding means that holds the other end of the elastic member and is rotatably or slidably disposed, a driving means that drives the rotating or sliding means, and a control means that controls the driving means; A tone arm driving device comprising: displacement detecting means for detecting displacement of the tone arm with respect to the rotating or sliding means and supplying this detection signal to the control means. 2. The tone arm drive device according to claim 1, wherein the elastic member is a plate spring. 3. The rotating means comprises a rotatably provided gear and a holding part that is interlocked with the gear and holds the elastic member.
Tone arm drive device as described in section. 4. The tone arm driving device according to claim 1 or 3, wherein the driving means includes a motor and a worm that is fixed to the rotating shaft of the motor and engages with the gear. . 5. The tone arm drive device according to claim 1 or 2, wherein the displacement detecting means is a strain gauge fixed to the elastic member.