JPS6226802Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tone arm horizontal/vertical rotation device using electromagnetic means.

Recently, various methods have been proposed that use electromagnetic means (a type of linear motor) to perform horizontal rotation of the tone arm during lead-in/lead-out and vertical rotation during cueing up/down. ing. The present invention greatly simplifies the structure and allows the electromagnetic means to be housed below the motor board (the top plate of the record player's cabinet).

Hereinafter, a detailed description will be given with reference to embodiments shown in the drawings.
In FIG. 1, 1 is a tone arm, 2 is a counterweight, 3 is a motor board, and 4 is a tone arm stand, which serves as a bearing for the horizontal rotation shaft 5 of the tone arm 1. The tone arm stand 4 is fixed on the motor board 3. A horizontal rotation shaft 5 of the tone arm 1 is rotatable with respect to the tone arm stand 4 by a ball bearing 6.
A U-shaped support portion 5a is formed at the top of the horizontal rotation shaft 5, and the tone arm 1 is attached to this support portion 5a.
It is rotatably supported in the vertical direction at a pivot 5b. The horizontal rotation shaft 5 is hollow,
Moreover, a horizontal rotation plate 7 is attached to the lower end. A vertical shaft 8 fixed to the tone arm 1 passes through the hollow portion of the horizontal rotation shaft 5.

Next, the horizontal rotation device for the tone arm 1 will be described in detail with reference to FIGS. 1, 3, and 4. The horizontal rotation device utilizes electromagnetic means consisting of a magnet (permanent magnet) and a yoke for forming a magnetic field, and a coil placed in this magnetic field. Such electromagnetic means includes a drive electromagnetic means that applies horizontal rotational force to the tone arm 1 during lead-in and lead-out, and a drive electromagnetic means that applies horizontal rotational force to the tone arm 1 during lead-in and lead-out, and a drive electromagnetic means that suppresses low-frequency resonance of the tone arm that occurs during performance (called Q dump). ) and servo electromagnetic means for controlling the speed of horizontal rotation of the tone arm. The driving electromagnetic means includes a magnet mounting plate 9 made of a magnetic material attached to the lower surface of the motor board 3, a magnet 10 fixed to this mounting plate 9, and a magnet 10 attached to the magnet mounting plate 9 in such a way as to be in contact with one end of this magnet 10. It is composed of a fixed yoke 11 and a hollow driving coil 12 fixed on a horizontal rotating plate 7. The yoke 11 is inserted into the hollow part of the drive coil 12. The servo electromagnetic means is similarly composed of a magnet 13, a yoke 14, and a servo coil 15, and is fixed to the magnet mounting plate 9 and the horizontal rotating plate 7, respectively. The positional relationship between the driving electromagnetic means and the servo electromagnetic means is shown in Fig. 3 (bottom view showing the magnet mounting plate 9 and various parts provided on this mounting plate) and Fig. 4 (horizontal rotation plate 7 and this This is clearly shown in the bottom view (bottom view) showing the parts provided on the pivot plate. In addition, in order to avoid complicating the drawing,
The figure shows a magnet 1 constituting the driving electromagnetic means.
0, yoke 11, and coil 12 are only shown.

Next, a vertical rotation device for the tone arm 1 will be explained with reference to FIGS. 2 and 4. The vertical rotation device is also constructed of electromagnetic means in the same way as the horizontal rotation device described above, but it is installed inside a cylindrical shield case (magnetic material) 16 provided to prevent mutual magnetic influence between the two devices. Contains electromagnetic means for vertical drive. FIG. 2 shows a cross-sectional view of the inside of the shield case 16. The vertical drive electromagnetic means also includes a drive electromagnetic means and a servo electromagnetic means. In FIGS. 2 and 4, the magnet 17 and yoke 18 fixed in the case 16 and the lower end of the vertical shaft 8 (which is connected to the horizontal rotating plate 7 and the through hole 19 provided in the case 16) are shown. A driving electromagnetic means is constituted by a driving coil 20 fixed to a case 16 (facing inside the case 16). The yoke 18 is inserted into the hollow part of the drive coil 20.
In FIG. 2, only the drive coil 20 is shown, and the magnet 17 and yoke 18 are not shown in order to avoid complicating the drawing. A magnet 21 and a yoke 22, which are also fixed in the case 16, and a servo coil 23 (this is shown by a broken line only in FIG. 4) fixed to the lower end of the vertical shaft 8, are used for the servo. Electromagnetic means are configured. The drive coil 20 and the servo coil 23 are integrated by a U-shaped fixture 24, and are fixed to the lower end of the vertical shaft 8 as described above. By the way, when the drive coil 20 and the servo coil 23 are arranged close to each other, leakage magnetic flux of the magnetic flux generated by the current flowing through the drive coil 20 interlinks the servo coil 23. Electric power will be generated, which is not desirable. Therefore, in this embodiment, a compensation coil is wound around the center of the servo coil 23 separately from the servo coil 23. As shown in FIG. 5, the compensation coil 20' is connected in series with the drive coil 20, and is configured so that a magnetic field distribution is generated in the opposite direction to the magnetic field of the drive coil 20. . Therefore, when a current is passed through the drive coil 20, a magnetic flux opposite to the leakage flux generated by the drive coil 20 is generated in the compensation coil 20', and the two cancel each other out, causing unnecessary magnetic flux to occur. Generation of electricity is prevented.

Further, in the illustrated embodiment, a horizontal position detection device for detecting the rotational position of the tone arm in the horizontal direction and a vertical position detection device for detecting the rotational position of the tone arm in the vertical direction are provided.

The vertical position detection device is composed of a photocoupler 25 attached to the inner wall of the shield case 16 and a shutter plate 26 attached to the vertical shaft 8 together with a driving coil 20. The photo coupler 25 has a light emitting element 25a and a phototransistor 25b facing each other with a shutter plate 26 in between.

The horizontal position detection device is composed of through holes 27a, 27b for setting performance conditions provided in the horizontal rotation plate 7, and a photo coupler 28 attached to the magnetic mounting plate 9 for detecting the through holes 27a, 27b. has been done. Photo coupler 28 has through hole 27
It has two sets of light emitting elements and phototransistors facing each other with a and 27b in between. The photo coupler 28 is fixed at a position facing a photo coupler 29 constituting an inside force canceling device which will be described later (see FIG. 3), but is not shown in FIGS. 1 and 2. . Through holes 27a, 27b
The position and length of the disc are set according to the size of the record and the position of the sound groove.

Further, in this embodiment, an inside force canceling device using the above-mentioned horizontal drive electromagnetic means is provided. This device is composed of a photo coupler 29 attached to a magnet mounting plate 9 and an inside force through hole 30 provided in a horizontal rotating plate 7. The photo coupler 29 consists of a light emitting element 29a and a phototransistor 29b facing each other with a through hole 30 in between. Through hole 30
is shaped so that the amount of light hitting the phototransistor 29b changes in response to rotation of the tone arm so as to reliably cancel out the inside force that changes depending on the position of the tone arm.

Further, in this embodiment, when the tone arm is placed on an armrest stand (not shown), it is configured to be locked by a magnet 31.
That is, as shown in FIG. 2, a magnet 31 attached to the inner wall of the shield case 16 attracts the fixtures (magnetic material) 24 of the coils 20 and 23 attached to the lower end of the vertical shaft 8, thereby attaching the tone arm. Hold it on the armrest stand. Furthermore, during a performance when the tone arm is removed from the armrest stand, this magnet 31 prevents any force from being applied to the tone arm in the downward direction (the direction in which the record stylus contacts the record surface). Therefore, the distance between the mounting tool 24 and the magnet 31 during performance (in a state where the record stylus is in contact with the record surface) is such that there is a certain distance between them. Therefore, when the tone arm is locked on the armrest base, the record needle is located below the surface of the record.

The operations of the horizontal/vertical rotation device, inside force canceling device, etc. described above will be more clearly understood by referring to the circuit diagram of FIG. 6 described below.

In FIG. 6, Q ₁ and Q ₂ are transistors for selecting the direction of current flowing through the horizontal drive coil 12 (that is, selecting lead-in/read-out of the tone arm), and OP ₁ is a transistor Q ₁ , _Q2 , and _A1 is an amplifier that amplifies the induced voltage generated in the horizontal servo coil 15. Q ₃ and Q ₄ are transistors for selecting the direction of current flowing through the vertical drive coil 20 (that is, selecting tone arm cueing up and cueing down), and OP ₂ is a switching transistor for transistors Q ₃ and Q ₄ . A comparator circuit _A2 is an amplifier that amplifies the induced voltage generated in the vertical servo coil 21.

First, in the stopped state, the horizontal drive coil 1
2 and the vertical drive coil 20, it is necessary to prevent any current from flowing through them. In the stopped state, zero balance is adjusted, for example, by adjusting the counterweight. In this stopped state, a constant voltage is input to terminals T ₃ and T ₇ . At this time, the voltages are divided by resistors so that voltages equal to the (+) sides of the comparison circuits OP ₁ and OP ₂ are input to the (-) sides, respectively. Therefore, the outputs of the comparison circuits OP ₁ and OP ₂ become O, and the transistors Q ₁ , Q ₂ , Q ₃ , and Q ₄ are all turned off. Therefore, no current flows through the drive coils 12 and 20.

To raise the tone arm, input a constant voltage to terminal T ₁ , divide it with a resistor, and set it to (+).
so that a voltage higher than that on the (-) side of the comparator circuit _OP2 is input to the (-) side of the comparator circuit OP2. Then, the output of the comparator circuit _OP2 becomes L level. Therefore, the transistor _Q4 becomes conductive, and current flows from the drive coil 20 to the power supply -Vcc via the transistor _Q4 , and the tone arm rises. On the other hand, to lower the tone arm, input a constant voltage to terminal T ₂ and divide it with a resistor, and the voltage lower than the (+) side is applied to the comparison circuit OP _2.
so that it is input on the (-) side of Then, the output of comparator circuit OP ₂ becomes H level, and the transistor
Q ₃ turns on. Therefore, current flows from the power supply +Vcc to the drive coil 20 through the transistor _Q3 , and the tone arm moves downward.

During performance, by inputting a constant voltage to the terminal _T4 , the output of the comparator circuit _OP2 is set to H level, and the drive coil 20 is connected via the transistor _Q3 .
By passing a current through, stylus pressure can be applied to the record stylus. The stylus pressure is a variable resistor for partial pressure.
It can be varied by adjusting VR ₁ .

Further, the voltage induced in the servo coil 21 is input to the (-) side of the comparator circuit OP ₂ via the amplifier A ₁ . Therefore, the current flowing through the drive coil 20 is controlled according to the induced voltage, and Q-dump or speed servo control is achieved.

To operate the tone arm in lead-out operation, input a constant voltage to terminal T ₅ , and then set the output of comparator circuit OP ₁ to H level and make transistor Q ₁ conductive. To operate the tone arm in lead-in operation, input a constant voltage to terminal T ₅ . By inputting a constant voltage to the comparator circuit OP ₁
It is clear from the above description that current can be caused to flow through the horizontal drive coil 12 by setting the output of Q2 to L level and making the transistor _Q2 conductive.

Furthermore, the voltage induced in the servo coil 15 is input to the comparator circuit _OP1 via the amplifier _A2 , thereby achieving horizontal Q-dump or speed servo control. In addition, a voltage responsive to the voltage output from the photo coupler 29 for inside force cancellation IFC described above is inputted to the terminal _T8 , and the current flowing to the horizontal drive coil 12 via the transistor _Q1 is controlled. By doing so, the inside force can be canceled. Note that since the size of the inside force also depends on the stylus pressure, it is convenient to adjust the variable resistor VR ₂ for adjusting the inside force in conjunction with the variable resistor VR ₁ for adjusting the stylus force.

Note that the resistors Rf ₁ and Rf ₂ that constitute the feedback circuit of the amplifiers A ₁ and A ₂ can be switched according to each operation mode of the record player, so that the level of Q dump and speed servo can be adjusted. It is becoming. In other words, when the tone arm is cued up (raised), when the tone arm is cued up (descent)
It can be switched during zero balance adjustment in the stopped state, and during performance.

Furthermore, instructions and stop signals for tone arm lead-in/lead-out, cueing up/down, etc. can be derived from the photo couplers 25, 28, etc. constituting the above-mentioned horizontal/vertical position detecting device. Furthermore, in record players that have a mechanism that automatically adjusts the zero balance (for example, moving a counterweight using a motor), the output of the photo coupler 25 that constitutes the vertical position detection device described above is used. The zero balance point can be found by

As described above, the device of the present invention includes a tone arm, a horizontal rotation shaft having a hollow portion and having a support portion on the upper part that supports vertical rotation of the tone arm, and a horizontal rotation shaft that horizontally rotates the horizontal rotation shaft. a bearing provided on the top plate of the cabinet to freely support the tone arm, a horizontal rotating plate attached to the lower end of the horizontal rotating shaft extending below the top plate of the cabinet, and a horizontal rotating plate fixed to the tone arm. The vertical shaft extends downward through the hollow part of the horizontal rotation shaft and the through hole of the horizontal rotation plate, and a constant magnetic field is applied by the magnet and yoke, and a lead-out or lead-in voltage is supplied to the horizontal rotation. a horizontal drive coil that horizontally rotates the tone arm in the opposite direction together with a moving plate; and a horizontal servo coil that induces a voltage by applying a constant magnetic field by a magnet and a yoke to control the current flowing through the horizontal drive coil. , a vertical drive coil that raises or lowers the tone arm along the vertical axis by applying a constant magnetic field by the magnet and yoke and supplying a cueing up or down voltage; a vertical servo coil that induces a current to control the current flowing through the vertical drive coil; and a horizontal position detection device that detects the horizontal rotational position of the tone arm and generates a lead-out or lead-in voltage. , and a vertical position detection device for detecting the vertical rotational position of the tone arm and generating a cueing up or down voltage. An electromagnetic means and an electromagnetic means for vertical rotation can be provided, and the horizontal rotation speed and vertical rotation speed of the tone arm can be controlled by the respective servo electromagnetic means provided for each of these electromagnetic means. Since the servo can be activated to perform stable horizontal and vertical rotations.

Further, according to the present invention, instruction signals such as tone arm lead-in/lead-out and cueing up/down are generated by detecting the horizontal rotational position and vertical rotational position of the tonearm. This makes it possible to smoothly automate the performance of records electromagnetically, making it extremely useful.

[Brief explanation of the drawing]

The drawings all show a horizontal/vertical rotation device for a tone arm according to the present invention; FIG. 1 is a partially sectional side view, FIG. 2 is a partially sectional side view, and FIG. 3 is a partially sectional side view. Figure 4 is a bottom view of the magnet mounting plate seen from below, Figure 4 is a bottom view of the horizontal rotation plate seen from below, Figure 5 is a diagram showing the drive coil, servo coil, and compensation coil, and Figure 6 is a diagram showing the drive coil, servo coil, and compensation coil. It is an electrical circuit diagram. 1 is a tone arm, 5 is a horizontal rotation axis, 7 is a horizontal rotation plate, 8 is a vertical axis, 10, 13, 17, 21 are magnets, 11, 14, 18, 22 are yokes,
12, 15, 20, 21 are coils.

Claims (1)

[Scope of utility model registration request] a tone arm, a horizontal rotation shaft having a hollow portion and a support portion for vertical rotation of the tone arm; a horizontal rotating plate attached to the lower end of the horizontal rotating shaft extending below the top plate of the cabinet; a hollow portion of the horizontal rotating shaft fixed to the tone arm; A constant magnetic field is applied by the vertical axis extending downward through the through hole in the horizontal rotating plate, a magnet and a yoke, and a lead-out or lead-in voltage is supplied, so that the tone arm is moved in the opposite direction along with the horizontal rotating plate. A horizontal drive coil that rotates horizontally, a horizontal servo coil that receives a constant magnetic field from a magnet and a yoke, induces a voltage, and controls the current flowing through the horizontal drive coil, and a constant magnetic field that is applied by a magnet and a yoke. a vertical drive coil that raises or lowers the tone arm along with the vertical axis by being supplied with a cueing up or down voltage; and a vertical drive coil that induces a voltage when a constant magnetic field is applied by a magnet and a yoke. a vertical servo coil for controlling current flowing through the tone arm; a horizontal position detection device for detecting the horizontal rotation position of the tone arm and generating a lead-out or lead-in voltage; 1. A horizontal/vertical rotation device for a tone arm, comprising a vertical position detection device for detecting a moving position and generating a cueing up or down voltage.