JPH0123841B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of exciting an electromagnetic plunger for driving a tone arm of a record player.

(Prior Art) In excitation of the electromagnetic plunger that drives the tone arm, it is possible to maintain the plunger position of the electromagnetic plunger by applying a holding current to the solenoid of the electromagnetic plunger (hereinafter simply referred to as the electromagnetic plunger). When driving the plunger, it is necessary to supply an operating current greater than the holding current to the electromagnetic plunger. For this reason, in a record player, an operating current is supplied to the electromagnetic plunger from the time a drive signal is generated to drive the tone arm in the direction of the record, and after the tone arm contacts the record, a holding current is supplied to the electromagnetic plunger. That's what I do. Conventionally, the operating current is switched to the holding current using a timer using an electrical time constant circuit, and switching is performed by a set time elapsed signal of the timer, or by mechanically changing the position of the arm lifter that raises and lowers the tone arm. The detection signal was used for switching.

However, in the case of the former, especially when the arm lifter is driven via an oil damping device, changes in ambient temperature not only change the descending speed of the arm lifter, that is, the tone arm, but also change the time constant of the electrical time constant circuit. Therefore, the set time must be set with safety in mind. For this reason, the period during which the operating current is applied becomes long, and the current consumption also increases.

Furthermore, the latter method not only requires a long time to adjust the position of the mechanical switch, but also has the disadvantage of being expensive.

(Object of the Invention) The present invention has been made in view of the above, and is based on the following: After the stylus reaches the record disc stably and reliably without using a timer or mechanical switch,
It is an object of the present invention to provide a method of exciting an electromagnetic plunger that can switch from an operating current to a holding current.

This object, according to the present invention, is a record player equipped with an arm lifter that moves a tone arm toward the surface of a record by being driven by an electromagnetic plunger whose solenoid is excited by an operating current. This is achieved by first detecting that the tracking error has reached a predetermined value after excitation, and switching the operating current to the holding current based on this detection signal.

The present invention will be explained below using examples.

(Structure of the Invention) FIGS. 1a, b, and c are schematic plan views showing an example of a conventional tone arm and arm lifter of a linear tracking record player;
A sectional view and a BB sectional view of FIG. 1a,
FIG. 2 is a block diagram showing an embodiment to which the present invention is applied.

1 is a tone arm. 2 is record 15
This drive plate is driven by the rotation of the tone arm 2 in a plane parallel to the surface of the tone arm 2 (hereinafter referred to as a horizontal plane). A pivot receiver 3-1 protruding from the arm base 3 is integrally formed on the arm base 3, and the drive plate 2 and the L formed on the drive plate 2 are integrally formed on the arm base 3.
A pivot 2-1 fixed to a letter-shaped protrusion 2-3 is received by a pivot receiver 3-1. On the other hand, the protrusion 1-1 of the tone arm 1 forms a pivot receiver, and the pivot 2-2 fixed to the protrusion 2-3 and the protrusion 2-4 of the drive plate 2 is connected to the protrusion 1-1 of the tone arm 1. It is configured to be received by a pivot receptacle formed in the. Here, the pivot 2-1 and the pivot receiver 3-1 form a pivot means 4 for pivotally supporting the tone arm 1 on the arm base 3 in a horizontal plane.
2 and the pivot receiver formed on the protrusion 1-1 of the tone arm 1 allows the tone arm 1 to be connected to the record disc 1.
A plane perpendicular to the surface of 5 (hereinafter referred to as a vertical plane)
The tone arm 1 is rotatably supported in the horizontal plane and the vertical plane, and the driving plate 2 is connected to the tone arm 1.
Tone arm 1 is rotated in the horizontal plane by
is pivoted to rotate in the horizontal plane by a rotation angle in the horizontal plane. A pick-up cartridge 6 is detachably attached to the tip of the tone arm 1.

A U-shaped support member 7 is fixed to the arm base 3 opposite the free end of the drive plate 2. A light emitting diode 8 and a phototransistor 9 shown in FIG.
A shutter 10 that protrudes between the two is firmly fixed. The shutter 10 is configured to limit the light from the light emitting diode 8 reaching the phototransistor 9 by the rotation of the drive plate 2 due to the rotation of the tone arm 1 in the horizontal plane.
A tracking error detector 11 is formed by the phototransistor 9 and the shutter 10.

On the other hand, the bearing body 12- fixed to the arm base 3
1 and 12-2 are rotatably equipped with arm lifter 1.
3 is installed. A V-shaped notch 13-1 is formed on the circumferential surface of one end of the arm lifter 13, and a holding member 1 having a V-shaped cross section that protrudes from and is fixed to the upper surface of the tone arm 1 is attached to the notch 13-1. -2 is in contact with it. A crank 14 is fixed to the other end of the arm lifter 13.

On the other hand, the arm base 3 has an electromagnetic plunger 16.
is attached to the plunger 16-1 of the electromagnetic plunger 16, and a connecting rod 17 whose one end is rotatably attached to the crank 14 is connected to the plunger 16-1 of the electromagnetic plunger 16. Further, a spring 18 is attached to the plunger 16-1, which biases the tone arm 1 in a direction to bring it into contact with a stopper 3-2 formed to protrude from the arm base 3 via the crank 14 and the arm 13. When the electromagnetic plunger 16 is in a non-excited state, the tone arm 1 is brought into contact with the stopper 3-2 by the spring 18, and the stylus tip 19 is brought into contact with the record disc 1.
5 and away from the surface of electromagnetic plunger 1.
6 is energized, the connecting rod 17 is pulled toward the electromagnetic plunger 16 against the force of the spring 18, the arm lifter 13 is rotated in the direction of the record 15, and the tone arm 1 is moved toward the record 15 by its own weight. It is configured to rotate in the direction of. Note that, as in the conventional case, when the output of the tracking error detector 11 reaches a set value, the arm base 3 is moved by a drive means (not shown) so as to reduce the output of the tracking error detector 11.
is configured to move toward the inner circumferential side of the record 15. 1-3 is a weight for balance fixed to the tone arm 1.

Reference numeral 20 denotes a tone arm operating switch. The operating voltage V _p is supplied to the tone arm operating switch 20 , and the operating voltage V _p via the tone arm operating switch 20 is applied to a resistor 21 and a capacitor 22 .
It is supplied to a differentiating circuit 23 consisting of. The output of the differentiating circuit 23 consists of an operational amplifier 24 to which the voltage of a voltage source 25 is supplied as a reference voltage.
Comparator 26 that detects the positive side output of 3 and shapes the waveform.
and an operational amplifier 27 to which the voltage of the voltage source 28 is supplied as a reference voltage, which detects the negative output of the differentiating circuit 23 and supplies it to a comparator 29 for waveform shaping. The output of comparator 24 is supplied to flip-flops 30 and 31 as a set signal, and the output of comparator 29 is supplied to flip-flop 30 as a reset signal.

The output of the tracking error detector 11 is comprised of an operational amplifier 32 supplied with the voltage of a voltage source 33, and is supplied to a comparator 34 that detects when the tracking error has exceeded a predetermined value lower than the set value. The output of comparator 34 is supplied to flip-flop 31 as a reset signal.

The voltage at the Q output terminal of the flip-flop 30 is supplied to the base of a transistor 35 having a load resistor 36 and driving the electromagnetic plunger 16;
It is supplied as one input to AND gates 38 and 39. The voltage at the Q output terminal of flip-flop 31 is provided as the other input of AND gate 38. The output of the AND gate 38 is supplied as the other input of the AND gate 39, and is also supplied to the base of a transistor 40 that drives a mute relay 41. Miyuto Relay 4
The contact 42 of No. 1 is connected between the output end of the pick-up cartridge 6 and the ground.
The output of the pickup cartridge 6 is muted while the pickup cartridge 6 is on.

On the other hand, the output of the AND gate 39 and the output of the transistor 35 are supplied to the base of a transistor 43 that directly drives the electromagnetic plunger 16.

(Operation of the invention) In one embodiment to which the present invention configured as described above is applied, a record disc 1 is
It is assumed that the turntable on which 5 is placed has already been driven to rotate.

When the tone arm operation switch 20 is in the OFF state, the tone arm 1 is lifted to a position where it contacts the stopper 3-2 by the action of the spring 18, and the stylus tip 19 is moved to a position away from the surface of the record 15. is maintained.

When the tone arm operating switch 20 is turned on, the voltage V _p is supplied to the differentiating circuit 23 via the tone arm operating switch 20 as shown in FIG. 4a. The output of the differentiating circuit 23 is output when the tone arm operation switch 20 is turned on and off as shown in FIG. 4b.
Generates positive and negative outputs in synchronization with off. The positive spike output of the differentiating circuit 23 is detected and waveform-shaped by the comparator 26, and the comparator 26 is configured as shown in FIG.
As shown in FIG. 2, a synchronized pulse is generated when the tone arm operation switch 20 is turned on. On the other hand, differentiator circuit 2
The negative spike output of 3 is detected and waveform-shaped by a comparator 29, which generates a pulse synchronized when the tone arm operating switch 20 is turned off, as shown in FIG. 4d. Therefore, the output from the Q output terminal of the flip-flop 30 generates a positive output while the tone arm operation switch 20 is on, as shown in FIG. 4e. As a result, the transistor 35 is controlled to be on during the on period of the tone arm operation switch 20, and the electromagnetic plunger 1
6 is excited. In this case transistor 3
The current flowing through the electromagnetic plunger 16 by the load resistor 36 of No. 5 is limited to the holding current of the electromagnetic plunger 16.

On the other hand, the flip-flop 31 is set by the output of the comparator 26, and the output from the Q output terminal of the flip-flop 31 becomes high potential as shown in FIG. 4g almost at the same time as the tone arm operation switch 20 is turned on. When the output from the Q output terminal of the flip-flop 31 becomes a high potential, the AND gate 38
The output of the AND gate 38 becomes a high potential, and the output of the AND gate 39 becomes a high potential. As a result, the transistor 40
and 43 are controlled to be in the on state.

Since the transistor 43 is turned on, the collector current of the transistor 43 flows through the electromagnetic plunger 16 superimposed on the collector current of the transistor 35, that is, the holding current of the electromagnetic plunger 16. Here, since no load resistance other than the electromagnetic plunger 16 is connected to the transistor 43, the electromagnetic plunger 16 is connected to the transistor 43.
The value of the current flowing through the transistor 35 is large, and this current value is set so that when it is superimposed on the holding current by the transistor 35, it becomes the operating current value. Therefore, the electromagnetic plunger 16 is excited by the operating current from the time the tone arm operating switch 20 is turned on, as shown in FIG. 4h.

Due to this excitation of the electromagnetic plunger 16, the plunger 16-1 is attracted against the force of the spring 18, and the connecting rod 17 moves upward in FIG. rotate in the direction. Arm lifter 1
Due to this rotation of 3, the tone arm 1 moves in the direction of the record 15 along with the movement of the arm lifter 13 due to its own weight, and when the stylus tip 19 of the pick-up cartridge 6 is in contact with the surface of the record 15, the tone arm 1 is moved toward the record 15 due to its own weight. The arm 1 stops moving in the vertical direction. Further, the arm lifter 13 is further lowered to a predetermined position in the vertical plane direction.

On the other hand, since the transistor 40 is turned on, the relay 41 is energized, the contact 42 is turned on, and the output terminal of the pickup cartridge 6 is grounded via the contact 42.
The output of the pickup cartridge 6 is muted. This mute is performed almost simultaneously when the tone arm operating switch 20 is turned on.

As the stylus tip 19 comes into contact with the surface of the record 15, the stylus 19 moves along the record 15 as the record 15 rotates, following the sound groove of the record 15.
5 and in the inner circumferential direction of the record 15. Due to this movement of the stylus tip 19, the tone arm 1 also moves in the radial direction of the record 15 and in the inner circumferential direction of the record 15 along with the movement of the stylus 19. Due to this movement of the tone arm 1, the shutter 10 also moves, and the amount of light received by the phototransistor 9 increases. In other words, the tracking error increases. When the output of the phototransistor 9 exceeds the voltage of the voltage source 33, that is, when the tracking error exceeds a predetermined value set by the voltage value of the voltage source 33, the comparator 34 operates as shown in FIG. Generates high potential output. The generation of the high potential output of the comparator 34 resets the flip-flop 31, and the output from the Q output terminal of the flip-flop 31 becomes a low potential as shown in FIG. 4g. When the output from the Q output terminal of flip-flop 31 becomes low potential, the outputs of AND gates 38 and 39 become low potential, and transistors 40 and 43 are controlled to be off. As a result, Miyuto Relay 4
1 is de-energized, the contact 42 is turned off, and the mute of the output of the pickup cartridge 6 is released. At the same time, the excitation current of the electromagnetic plunger 16 by the transistor 43 is cut off, and only the holding current by the transistor 35 flows through the electromagnetic plunger 16, so that the position of the arm lifter 13 is maintained.

However, the transistor 43 is turned off when the tracking error detector 11 detects a tracking error of a predetermined value or more.
5 has reached the surface of the arm lifter 13, it is not necessary to supply an operating current to the electromagnetic solenoid 16, and it is sufficient to maintain the position of the arm lifter 13 by supplying only a holding current. Also, the transistor 40
Since the stylus tip 19 has already reached the surface of the record disc 15 when the stylus tip 19 is controlled to be in the OFF state, the shock noise generated when the stylus tip 19 comes into contact with the record disc surface is muted.

On the other hand, at the same time as the miute is released, the electromagnetic plunger 1
Since the supply of collector current from transistor 43 to transistor 6 is stopped, power consumption is reduced.

Further, when the tone arm operating switch 20 is turned off, the comparator 29 generates an output, the flip-flop 30 is reset, the output from the Q output terminal of the flip-flop 30 becomes a low potential, and the transistor 35 is turned off. As a result, the holding current of the electromagnetic plunger 16 is also cut off, and the electromagnetic plunger 16 becomes in a non-excited state. With the electromagnetic plunger 16 in a non-excited state, the plunger 16-1 moves downward in FIG. During this rotation, the holding member 1-2 of the tone arm 1 comes into contact with the notch 13-1 of the arm lifter 13, and by the subsequent rotation of the arm lifter 13, the tone arm 1
moves in a direction away from the surface of the record 15, contacts the stopper 3-2, and stops rotating. This rotation of the tone arm 1 causes the stylus tip 19 to separate from the surface of the record 15.

Note that the AND gate 39 may be omitted and the transistor 43 may be driven by the output of the AND gate 38.

Next, other embodiments to which the present invention is applied will be described.

FIG. 4 is a block diagram of another embodiment to which the present invention is applied.

In another embodiment to which the present invention is applied, the differentiating circuit 23, comparators 26, 29, flip-flops 30, 31, and AND gate 38 are substantially replaced by a microcomputer 50. The microcomputer 50 includes a first control means that maintains the output terminal C at a high potential during a period when the high potential signal is supplied to the input terminal A, and
The output terminal D is maintained at a high potential during the period from the time when a high potential signal is supplied to the input terminal A to the time when the high potential signal is supplied to the input terminal A and the first high potential signal is supplied to the input terminal B. and second control means.

The input terminal A of the microcomputer 50 is supplied with the voltage V _p via the tone arm operation switch 20, and the input terminal B is supplied with the output of the comparator 34, that is, a signal indicating that the tracking error exceeds a predetermined value. It has been supplied. Further, the output from the output terminal C of the microcomputer 50 is supplied as one input of the AND gate 39 and is also supplied to the base of the transistor 35, and the output from the output terminal D is supplied as the other input of the AND gate 39. It is also supplied to the base of the transistor 40.

The other configurations are the same as those of the embodiment to which the present invention is applied.

The operation of this embodiment constructed as described above is as shown in the flowchart of FIG. When the tone arm operation switch 20 is turned on, the output terminals C and D are brought to a high potential by the first and second control means. Therefore, the transistor 40
is controlled to be on, the output of the pickup cartridge 6 is muted, and the transistor 35
is controlled to be on, and a holding current flows through the electromagnetic solenoid 16. At the same time, the output of the AND gate 39 also becomes a high potential, the transistor 43 is controlled to be on, and the collector current of the transistor 43 flows through the electromagnetic solenoid 16 superimposed on the holding current, and the tone arm 1 moves in the direction of the record 15. do.

Then, the output of the tracking error detector 11 increases, and when the tracking error exceeds a predetermined value, the output of the comparator 34 becomes high potential. So the second
The control means sets the output terminal D to a low potential when the output of the comparator 34 first becomes a high potential. Since the output terminal D becomes a low potential, the transistor 40 is controlled to be off, and the muting of the output of the pickup cartridge 6 is released. At the same time, the output of the AND gate 39 becomes a low potential, the transistor 43 is controlled to be off, and the supply of the collector current of the transistor 43 to the electromagnetic solenoid 16 is stopped. This state continues until the tone arm operation switch 20 is turned off. In this case, before the output mute of the pick-up cartridge is released, the stylus tip 19
The fact that it is in contact with the surface of 5 is the same as in the previous embodiment.

Then, when the tone arm operation switch 20 is turned off, the output terminal C is brought to a low potential by the first control means, and the transistor 35 is turned off. Therefore, the electromagnetic plunger 16
becomes a non-excited state, the tone arm 1 is driven in the direction of the stopper 3-2, and the stylus tip 19 leaves the surface of the record. These actions are exactly the same as in one embodiment to which the present invention is applied.

(Effects of the Invention) As explained above, according to the method of the present invention, in a record player equipped with an arm lifter that is driven by an electromagnetic plunger whose solenoid is excited by an operating current and moves the tone arm in the direction of the record disc, After the solenoid is energized by the operating current, it is first detected that the tracking error has reached a predetermined value, and the moving speed of the tone arm is changed in order to switch the operating current to a holding current based on this detection signal. The solenoid is driven by the holding current after the stylus reaches the record in a stable and reliable manner, so that the period during which the operating current is applied does not become unnecessarily long. Furthermore, the stylus does not switch to the holding current before reaching the record surface, and the stylus reaches the record surface reliably.

In addition, in order not to use mechanical switches etc.
There is no need for a long time to adjust the position of a mechanical switch.

[Brief explanation of drawings]

Figures 1a, b, and c are schematic plan views showing an example of a conventional tone arm and arm lifter for a linear tracking record player, and A-A in Figure 1a.
View and BB view of FIG. 1a. FIG. 2 is a block diagram of an embodiment to which the present invention is applied. FIG. 3 is a timing diagram for explaining the operation of the embodiment shown in FIG. 2. FIG. 4 is a block diagram of another embodiment to which the present invention is applied. FIG. 5 is a flowchart explaining the operation of another embodiment to which the present invention is applied. 1...Tone arm, 6...Pickup cartridge, 8...Light emitting diode, 9...Phototransistor, 10...Shutter, 11...Tracking error detector, 13...Arm lifter, 1
5...Record, 16...Electromagnetic plunger, 1
9... Needle tip, 20... Tone arm operation switch, 23... Differential circuit, 26, 29 and 34...
... Comparators, 30 and 31 ... Flip-flops, 35, 40 and 43 ... Transistors, 4
1...Mute relay, 42...Relay contact.

Claims (1)

[Claims] 1. In a record player equipped with an arm lifter that moves a tone arm toward the record surface by being driven by an electromagnetic plunger whose solenoid is excited by an operating current, a tracking error occurs first after the solenoid is excited by the operating current. 1. A method for exciting an electromagnetic plunger, comprising detecting that the current has reached a predetermined value, and switching the operating current to a holding current based on this detection signal.