JPS6038762B2 - record player - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a record player in which a horizontal position servo is applied to a tone arm, and in particular, when the tone arm enters a playing state from a moving state, the control circuit is operated at an appropriate timing. This is what I did.

The present applicant previously proposed an electronically controlled record player in which a tone arm is provided with a horizontal drive motor and a vertical drive motor.

In this player, a horizontal drive motor rotates the tone arm from the rest position to a desired position above the cord, and at that position the tone arm is held in that position by applying a position servo to the horizontal drive motor, and then The arm is lowered by a vertical drive motor while the position servo is applied, and the side is lowered onto the sound groove of the record to begin the performance. After the performance is over, the vertical drive motor raises the arm, and then the horizontal drive motor rotates the arm to the next desired position. In addition, this player is equipped with a system control circuit (hereinafter simply referred to as system control) so that the first chord songs can be played in a pre-programmed order.The above-mentioned operation can be performed by pressing the start button provided on the player. This process is automatically and repeatedly performed based on instructions from the system controller. In a record player in which the horizontal position servo is applied to the arm in this way, it is necessary that the position servo be released when the arm is lowered and enters the playing state while the horizontal position servo is applied. The reason for this is that if a performance is performed while the position servo is applied, the stylus tip will forcefully trace the tone groove against the servo action that attempts to hold the stylus tip in that position. Therefore, conventionally, the descending time from when the arm starts descending from the holding position until the needle tip reaches the sound groove is estimated, and that time is set in advance.
When this set time elapsed, the horizontal position servo was canceled according to instructions from the system controller. However, the actual falling time varies from case to case, and therefore, with this method, the position servo is sometimes released too early or too late. For this reason, if the release is too early, the stylus tip may swing and fall to the wrong position before it reaches the tone groove, and if it is released too late, the stylus tip may be forced to move at the beginning of the performance. Tracing the sound grooves could damage the stylus tip or record, or impair the sound quality. The present invention is intended to solve the above problem, and an embodiment in which the present invention is applied to a record player having the above-mentioned horizontal drive motor and vertical drive motor will be described below with reference to the drawings.

In FIG. 1, a tone arm 1 is provided so as to be horizontally rotatable in the directions of arrows a and b by an arm shaft 2, as is conventionally known, and vertically rotatable in the directions of arrows c and d by a shaft 3. Cartridge 5 with regenerated needle 4 at the tip
and a song interval detector 37 are provided.

For this tone arm 1, a horizontal drive motor 6, a vertical drive motor 7, a horizontal position detector 8 and a vertical position detector 2 are provided.
6 are arranged. The horizontal drive motor 6 includes a rotor consisting of a coil 10 wound around a bobbin 9, and a stator consisting of a yoke 11 and a magnet 12.

The bobbin 9 is a support village 13 that is integrally provided on the arm shaft 2.
is attached to the tip of the The yoke 11 has a yoke portion formed in a rectangular ring shape as shown in the figure, and is attached to the arm shaft 2.
It has a curved shape in an arc centered on
The player is fixedly supported by appropriate means. A magnet 12 is provided on the lower part 11a of this yoke 11 by gluing or the like in the thickness direction, and the upper part 11b is
The bobbin 9 is rotatably attached to the magnet 12 with a predetermined gap. The vertical drive motor 7 includes a rotor consisting of a coil 16 wound around a bobbin 15 attached to the rear end of the tone arm 1, and a yoke 18 attached to the tip of a support village 17 provided on the arm shaft 2. The stator includes magnets 19 and 20. The yoke 18 is formed into a rectangular ring shape as shown in the figure, and has a guide portion 18a formed in the center thereof.
Moreover, the yoke member has a shape in which a guide portion 18a is formed in the center of the yoke member, which is curved into an arc shape centered on the shaft 3. Magnets 19 and 20 are fixed to the inner surfaces of the left and right side parts 18b and 18c of this yoke 18 by adhesive etc. with the same magnetic pole faces facing each other, and the guide part 18a
A bobbin 15 is rotatably fitted between two magnets 19 with a predetermined gap. The horizontal position detector 8 includes a slit plate 22 that is provided on the arm shaft 2 and rotates integrally with the arm shaft 2, and light emitting elements 23 that are fixedly supported above and below the slit plate 22, facing each other by appropriate means. and a light receiving element 24. A large number of slits 25 are arranged in the slit plate 22 along an arc centered on the arm axis 2. According to the above configuration, when the tone arm 1 horizontally rotates from the rest position together with the slit plate 22, the number of pulses corresponding to the number of slits 25 passing above the light receiving element 24, that is, the rotation angle, is sent as the horizontal position detection signal. can be obtained from the light receiving element 24 as follows.
This detection signal is transmitted to the system control circuit 38 and the horizontal speed control circuit 3.
2 and horizontal position detection circuit 33. As shown in FIG. 2, the vertical position detector 26 is provided with a rod-shaped magnet 28 provided on the lower surface of the support portion 27 of the tone arm, and is provided on the support village 17 and close to the magnet 28. It is composed of a core 29 and a coil 30 wound around the core 29.

The coil 30G is connected as a tuning coil for the oscillator 31. According to the above configuration, when the tone arm rotates in the directions of arrows c and d, the magnet 2
8 and the core 29 change, the coil 30
The inductance of changes. Therefore, from the oscillator 31, a vertical position detection signal having an oscillation frequency corresponding to the vertical rotation angle of the tone arm 1 is obtained. This detection signal is applied to the system control circuit 38 and the vertical speed control circuit 35. Mouse 6, position detector 8,
A horizontal speed servo system and a horizontal position servo system are configured by a horizontal speed control circuit 32, a horizontal position detection circuit 33, a DC amplifier 34, and the like. That is, the horizontal speed control circuit 32 outputs a speed control signal in response to the position detection signal from the horizontal position detector 8, and outputs this speed control signal.
This can be added. As a result, the coil 10' and the magnet 12
A current interlinking with the magnetic flux flows, and a horizontal force acts on this coil 10. As a result, the tone arm 1 moves to arrow a,
It is rotated at a constant speed in the b direction. Further, the horizontal position detection circuit 33 applies a position control signal to the coil 1W through the DC amplifier 34 based on the position detection signal of the horizontal position detector 8, so that the tone arm 1 is rotated to a predetermined position.
control to hold it in that position so that it does not swing horizontally. Mo
A vertical speed servo system is composed of a vertical position detector 26, an oscillator 31, a vertical speed control circuit 35, a DC amplifier 36, and the like.

The vertical speed control circuit 35 applies a vertical speed control signal to the coil 16 of the motor 7 through the DC amplifier 36 based on the vertical position detection signal from the oscillator 31. As a result, a current that interlinks with the magnetic flux of the magnets 19 and 20 flows through the coil 16, and a vertical force acts on the coil 16. As a result, the tone arm 1 is rotated at a predetermined speed in the directions of arrows c and d. Incidentally, the coil 16 of the motor 7 is configured to receive voltages for adjusting the stylus pressure and zero balance from a separately provided stylus force and zero balance adjustment circuit (not shown). With this voltage, it is possible to apply a desired stylus pressure to the tone arm 1 during performance, and also to provide balance in the raised state of the tone arm 1. The output signal of the cartridge 5 is output from output terminals 39a and 39b derived from the lower part of the arm 2.
It is designed so that it can be taken out and added to an audio amplifier system (not shown).

At the same time, the noise generated when the playback needle 4 lands on the record is detected by four noise detectors from the output terminal 39a, and this landing detection signal is applied to the system control circuit 38. The track interval detector 37 may be of a conventionally known type, such as one that detects a track interval based on the difference between the amount of light reflected from the sound groove surface of the record and the amount of light reflected from the feed groove (between tracks) surface. is used. This inter-music detection output signal is applied to the system control circuit 38. This record player is also provided with a start button 41 connected to the system control circuit 38, and by pressing the start button 041, the system control circuit 38 is connected to the system control circuit 38.
Each circuit is operated at a predetermined timing according to each instruction. Furthermore, this player is provided with a programming device (not shown).
Before starting the performance, the tone arm is rotated once from the rest position to approximately the center of the chord. During this time, the inter-song detector 37 memorizes the inter-song part of the record, and then the next play is performed. It is designed so that you can program it in the order you want it to play. Next, the operation of the above configuration will be explained.

First, the program device selects the number of songs on the record and sets the order of performance.

After the tone arm 1 is zero-balanced by the adjustment circuit, the stylus pressure is set and preparations are completed. Next, press start button 4 in this state. As a result, a control command signal is sent from the system control circuit 38 to the horizontal speed control circuit 32, the horizontal speed servo system starts operating, and the tone arm rotates at a predetermined speed in the direction of arrow a from the rest position. During this rotation, the song interval detector 37 detects the song interval on the record,
When the song interval before the first programmed song is detected,
A control release signal is sent from the system control circuit 38 to the horizontal speed control circuit 32, and a control command signal is also sent to the horizontal position control circuit 33. As a result, the horizontal speed servo system stops operating, and the tone arm 1 stops. At the same time, the horizontal position servo system is operated, and the tone arm 1 is held at that position so as not to swing in the horizontal direction. After a certain period of time, for example 0.5 seconds, has elapsed from this state, a descending command signal is sent from the system control circuit 38 to the vertical speed control circuit 35. As a result, the vertical speed servo system is operated, the tone arm is rotated at a predetermined speed in the direction of arrow d with the horizontal position servo applied, and the reproduction needle 4 is lowered. Noise generated when the playback needle 4 lands between predetermined songs on the record appears at the output terminal 39a, and this noise is detected by the landing detector 40. As a result, a control release signal is sent from the system control circuit 38 to the horizontal position detection circuit 33 and the vertical speed control circuit 35, and the horizontal position servo and vertical speed servo are released. At the same time, a voltage is applied to the coil 16 of the motor 7 from the adjustment circuit to apply a preset stylus pressure. With the above steps, the player enters the playing state.
When the performance of one or more selected pieces of music is finished, the song interval detector 37 detects the song interval at that time, and based on the detection signal, the system control circuit 38 sends an increase command signal to the vertical speed control circuit 35. is sent, thereby causing the tone arm 1 to rise.

When the tone arm stops rising, the horizontal speed control circuit 3
2 is operated by a control command signal, and the tone arm 1 rotates at a predetermined speed in the direction of arrow a or b depending on the next set song. When a predetermined song interval is detected by the song interval detector 37, the horizontal speed servo is released, the tone arm stops, and the same operation as described above is performed again. That is, the horizontal position servo is activated at the same time as the tone arm 1 is stopped, and 0.5 seconds later, the vertical speed servo is activated and the tone arm 1 is lowered. Then, the horizontal position servo and vertical speed servo are canceled due to the noise when the playback needle 4 lands, and the player enters the playing state again. The above-mentioned operation is repeatedly and automatically performed, and when all the programmed songs have been played, the tone arm is raised and rotated in the direction of arrow b to return to the rest position.

According to the above, the horizontal position servo is canceled based on the noise generated when the playback stylus 4 lands on a predetermined position on the record, the vertical speed servo is canceled, and the system control circuit 38, stylus pressure adjustment circuit, etc. Since we try to match the conditions of the performance state, we prevent the playback needle 4 from swinging before landing and landing on the wrong &calendar, or tracing the sound groove while the position servo is still applied. This can be prevented, and the operation timing of each other circuit can be set appropriately. Note that the above-mentioned operation is for auto-lead-in and auto-lead-out of the tone arm 1, but
It is also possible to manually operate the tone arm 1 and apply the horizontal position servo when the tone arm 1 is positioned at a desired position above the record. In this case, the reproduction needle 4 may be lowered with the horizontal position servo applied by the vertical speed servo, and the horizontal position servo and vertical speed servo may be canceled based on the noise when it lands. As described above, the present invention provides a horizontal position servo circuit (for example, a motor 6, a horizontal position detector 8, a horizontal position control circuit, 33), and a detection circuit (for example, a noise detection circuit 40) for detecting the noise generated when the tone arm descends and the stylus tip reaches the record. The present invention relates to a record breaker characterized in that the horizontal position servo is canceled based on a signal.

Therefore, according to the present invention, when entering the playing state, it is possible to prevent the playback needle 4 from swinging and landing at the wrong position, or from tracing the tone while the position servo is applied. be able to.

[Brief explanation of the drawing]

FIG. 1 is a perspective view and circuit diagram of the main parts of a player showing an embodiment of the present invention, and FIG. 2 is a side view of the main parts of FIG. 1. In addition, in the symbols used in the drawings, 1...Tone arm, 4...Regeneration needle, 6...Horizontal drive motor, 8...
...Horizontal position detector, 33...Horizontal position control circuit, 3
8...System control circuit, 39a, 39b...
Output terminal, 40... noise detector. Figure 2 Figure 1

Claims (1)

[Claims] 1. A horizontal position servo circuit that applies a horizontal position servo to the tone arm to hold the stylus at the desired position when the tone arm is rotated and the stylus is stopped at a desired position above the record; A detection circuit is provided to detect noise generated when the tone arm descends with the horizontal position servo applied and the stylus reaches the record, and releases the horizontal position servo based on the detection signal. A record player characterized by: