JPS5830288Y2 - Tone arm drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tone arm, and more particularly to a tone arm drive device that automatically reverses the driving direction of the tone arm when controlling the tone arm.

Conventionally, when moving the tone arm in the direction of the record in an automatic record player, it is common to move the tone arm from a drive source such as a phono motor via a link mechanism; Not only did it make a sound, but it also operated sequentially, and if you made a mistake, you had to start over from the beginning.

Further, even when a separate drive source is used so as not to apply a load to the phono motor or the like, the same drawback occurs when the tone arm is rotated to a predetermined position.

Furthermore, when stopping the tone arm in a predetermined position, it can be mechanically stopped by hitting a stopper.

The tone arm is stopped rotating by, for example, stopping the power supply to the rotation drive part, and the tone arm does not stop naturally at the desired position, such as stopping suddenly or overrunning. There were drawbacks such as unnatural movement, mechanical noise, and poor accuracy in stopping position.

The present invention aims to provide a tone arm driving device which eliminates the above-mentioned drawbacks, and which allows the tone arm to be rotated to a desired position no matter where the tone arm is located, and furthermore, when the tone arm is stopped, This system eliminates the unnaturalness of sudden stops and makes it stop gradually, and the stopping position is precisely achieved. A continuous control signal is obtained from a position detecting means associated with the tone arm to control the direction and speed of rotation of the tone arm.

The details of the present invention will be explained with reference to FIG. 1 and subsequent figures.

1 and 2 are structural diagrams of an embodiment of the present invention.

In the example shown in the figure, the tone arm 1 has a cartridge 1a having a stylus at its tip and a weight 1b at the other end, as usual, and a shutter at the lower end of the horizontal rotation shaft 2 of the tone arm 1. The plate 3 is pivotally mounted, and a drive unit 4 for directly rotating the horizontal rotation shaft 2 is provided at the intermediate part thereof, and a detector 5 for detecting the rotation speed is provided. A lid 6 for raising and lowering the arm 1 and a switch 1 for detecting the operation of the lid are provided, and a position detector 9 that can be rotated coaxially with the horizontal rotation axis 2 of the tone arm 1 is provided on the fixed part 8. will be established.

This position detector 9 has a light emitting element 10 and a light receiving element 11 with a shutter plate 3 in between.

This position detector 9 is connected to the knob 2130 via the belt 12.
It is commanded to be able to rotate by turning.

The circuit of the drive section 40 is shown in FIG.

As shown in FIG. 3, the drive unit 40 circuit includes a switch contact piece S2 arranged in connection with the lever 14 placed on the turntable board, a switch contact piece S1 of the switch γ related to the lifter 6, and an amplification circuit. A series circuit in which A1 is connected in series is connected to the midpoint between the resistor R to which electric currents E+E and -E are applied to both ends, and the light receiving element 11, and one end of the amplifying circuit Al is connected through the amplifying circuit A2. and is connected to the detector 5.

Next, the operation of the device having the above-described configuration will be explained.

In normal playing conditions, the lifter 6 is lowered, the contact piece S1 of the switch 7 is open, and the drive section 4
is not energized.

Therefore, the tone arm 1 is in a normal playing state without any force being applied to it.

Further, in this drive section 4, as shown in FIG. 4, for example, a disc-shaped armature 15 made of a magnetic material or the like is pivotally attached to the horizontal rotating shaft 2, and a coil 16 is wound around the armature 15 to surround the armature 15. Since the magnet 1γ is arranged in the same direction, when the coil 16 is energized, the resulting rotational torque changes almost sinusoidally as shown in FIG. Rotation angle is 45°
Since it is sufficient if there is a large torque, the shaded portion in FIG. 5 where the torque is large can be used.

In this case, since the deviation from the maximum torque point is only 10%, the drive torque can be considered to be approximately linear, so the rotational frictional resistance due to the brush that occurs when the drive unit 4 is driven using a DC motor, etc. There is no sound, and the instrument is in a playing state.

Next, by raising the lifter 6, the tone arm 1 is raised above the record surface, and the contact piece Sl of the switch 7 is activated.

If the contact piece S2 of the lever 14 is operated manually in this state.

The coil 16 of the drive section 4 is energized through the amplification circuit AI.

On the other hand, the output from the speed detector 5 is applied to the amplification circuit Al via the DC amplifier A2, and the reference voltage P, which is another input of the amplification circuit Al, is applied to the amplification circuit A1. The rotational speed of the drive section 4 is automatically feedback-controlled in accordance with the reference voltage P.

Further, when the reference voltage EP becomes Ov, it stops, and when it becomes a negative voltage, it rotates in the opposite direction.

In this case as well, the rotation speed depends on the voltage.

Here, the reference voltage P is obtained by using, for example, a cadmium sulfide cell as the light receiving element 11, connecting it in series with a resistor R, and applying voltages 1E and -E to both ends of this series connection.

Now, when the light-receiving element 11 is not completely hit by light, its resistance value is high and the reference voltage P becomes a positive potential.On the other hand, when the light-receiving element 11 is completely hit by light, its resistance value becomes low and it becomes a negative potential. Make it so that

At the first time, the shutter plate 3 moved with the rotation of the tone arm 1, which covered only half of the light receiving element 11.
There is a state as shown in Figure a, in which case the reference voltage is Ov.

Now, in FIG. 6a, as the edge 18 of the shutter plate 3 moves relative to the light receiving element 11, the reference voltage FEP changes according to the angle as shown by the curve a in FIG. 7.

If the light is blocked by the shutter plate 3, the seventh
As shown in the figure, the reference electric potential EP becomes a positive potential (+V), and the speed of the tone arm 1 is controlled in the direction of rotation toward the inside of the record.

Conversely, if the light hits the record, the speed is controlled so that it moves to the outside of the record.

Now, if the tone arm 1 is set to the outside by the operation of the auto switch lever 14, the tone arm 1 will automatically rotate inward at a constant speed, and the edge portion 18 of the shutter plate 3 As the light approaches the light receiving element 11 and gradually begins to be exposed to light, the reference voltage P increases to Ov.
As a result, the rotation speed of the tone arm 10 gradually slows down and stops exactly at the Ov position.

Conversely, even if the tone arm 1 is already inside, it will be rotated to the same angle O position, and even if it goes too far, it will be reversed again and returned to the angle O position.

Furthermore, if the shutter plate 3' is constructed such that the edge 18' is inclined as shown in FIG. 6, the reference voltage P changes from a position far away from the zero point, as shown in the curve shown in FIG. The movement of the tone arm 1 until it stops can be made smoother.

Furthermore, since the position detector 9 can be freely changed in position with the knob 13, if it is set to a position corresponding to the outside of the record, the tone arm 1 can be rotated to the outside of the record.

Furthermore, it can be set at any position.

In addition, the auto switch lever 14 is operated by 11, and the knob 13 is
By moving the tone arm 1, the tone arm 1 also rotates as the position detection moves, so the tone arm 1 can be arbitrarily rotated to a desired position without directly touching the tone arm 1.

1 with auto switch lever 14 set, lifter 6
By lowering the lifter 6, normal performance can be performed, and by raising the lifter 6, the tone arm 1 automatically rotates and stops at the position set by the knob 13.

In this way, the tone arm 1 can be used directly from any position.
It rotates to the target position and then stops while gradually decelerating to the target position.

Although the lifter 6 is operated manually here, it is of course possible to operate it using a plunger or other power source.

In this case, the tone arm was rotated by speed control, but this can also be done by a regular DC motor.

An example thereof is shown in FIG. In the example shown in FIG. 8, a DC motor 23 is installed in the fixed part 8 instead of the drive part 4 in FIG.
The first clutch plate 19a is attached to the lower surface of the shutter plate 3 of the horizontal rotation shaft 2, and the first clutch plate 19a is attached to the upper surface of the shaft 2a mounted on the position detector 9.
A second clutch plate 19a is provided opposite to the clutch plate 9a, and a gear 22 and a lever 20 are fitted and clamped onto the shaft 2a as shown in FIG.

The clutch plate 19b and the gear 22 are configured to be movable by a lever 20, and the lever 20 is normally pulled downward by a spring 25, and the clutch plates 19a and 19b are separated.

When the arm lifter 6 is moved upward, the lever 20 is raised by the lift spring 26, which is stronger than the spring 25, and the clutch plates 19a and 19b are connected.

On the other hand, in the drive circuit of this example, as shown in FIG.
This is a configuration in addition to 3.

Since the DC motor 23 rotates at a rotational speed proportional to the amount of human power, it operates almost the same as in the first embodiment.

In these embodiments, light is used for position detection, but
Magnets, Hall elements, and other differential transformers can also be used in the same way.

It is also obvious that the motor used can be controlled in reverse by changing the phase of an AC motor.

Since the present invention is constructed and operated as described above, it is possible to automatically rotate the tone arm to the desired position in any case, and the movement until it stops is smooth, gradually stopping, and the machine There is no physical shock, no vibration noise is generated, the target position can be changed freely, the tone arm can be operated without touching the tone arm, and there is no risk of damaging the needle or the like.

Furthermore, even if the tone arm should go too far past the stop position, it will automatically return to the desired position, so it can be lowered completely to the desired position.

[Brief explanation of the drawing]

Fig. 1 is a partially cross-sectional side view showing the main parts of the present invention, Fig. 2 is a perspective view of the drive section and position detector portion of Fig. 1, and Fig. 3 is the drive section of the present invention. The circuit diagram of Figure 4 is the circuit diagram of Figure 1.
Fig. 5 is an explanatory curve diagram showing the rotational torque and rotation angle of the drive unit, Fig. 6 is a plan view of the shutter plate used in the present invention, and Fig. 7 is a diagram showing the internal structure of the drive unit shown in the figure. A curve diagram showing the relationship between the rotation angle and the reference voltage for explanation, FIG. 8 is a side view of the drive unit with a partial cross section showing another embodiment of the present invention, and FIG. 9 is a diagram showing the relationship between the rotation angle and the reference voltage. FIG. 10 is a perspective view showing the relationship between levers and gears, and FIG. 10 is a circuit diagram of the drive section of FIG. 8. In the figure, 1 is a tone arm, 2 is a water rotation shaft, 3 is a shutter plate, 4 and 23 are drive parts, 5 is a rotation speed detector, 6 is a lifter, 9 is a position detector, 13 is a Knob, 1
4 is an auto switch lever.

Claims (1)

[Scope of utility model registration request] Related to means for driving the tone arm in the horizontal direction, means for detecting the horizontal position of the tone arm, means for detecting the horizontal rotation speed of the tone arm, and means for detecting the horizontal position of the tone arm. The external operating means for detecting the horizontal position of the tone arm and the means for detecting the horizontal position of the tone arm are configured to change a reference position by the external operating means, and the horizontal position detection output of the tone arm is determined by the external operating means. A tone arm driving device that controls means for driving the tone arm in the horizontal direction based on a comparison output between the horizontal rotation speed detection output and the horizontal position detection output.