JPS6339961B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a stylus force adjustment mechanism, in which a conductive rotating piece is pivoted in place of a cantilever within a cartridge case, and the tip of the rotating piece is brought into contact with a signal recording surface. To provide a stylus force adjustment mechanism which allows a predetermined stylus force to be obtained extremely simply and accurately by fixing the height of a cartridge when the cartridge is pressed.

Generally, a disc-shaped recording medium is played back by driving a backup cartridge to run parallel to the disc-shaped recording medium while the disc-shaped recording medium is being rotated at a constant speed, thereby reproducing the signals recorded on the recording medium. The device is known. This type of playback device is based on the premise that the stylus pressure of the cantilever in the pick-up cartridge is set to a predetermined stylus pressure with respect to the disc-shaped recording medium, and unless this is done, good playback cannot be performed. It is necessary to adjust the attitude of the stylus tip to a predetermined attitude when the stylus tip is brought into contact with the signal recording surface of the recording medium on the turntable.

However, the conventional disk-shaped recording medium playback device is
When the pick-up cartridge is installed in the carrier, the adjustment screw screwed into the carrier regulates the installation position of the cartridge and changes the needle tip posture, so the height of the carrier relative to the chassis can be adjusted. If the stylus is out of alignment, proper stylus pressure cannot be obtained and the signal recorded on the recording medium cannot be accurately reproduced.

Furthermore, in conventional playback devices, when confirming whether the pick-up cartridge has actually been adjusted to a predetermined stylus force, it is necessary to use a special stylus force adjustment tool or
Alternatively, the only way to judge whether the reproduced signal is good or bad is to actually reproduce the disc-shaped recording medium, which has drawbacks such as the work is extremely troublesome and time-consuming.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings. 1 and 2 are a schematic perspective view and a schematic vertical cross-sectional view, respectively, showing the internal structure of an example of a disk-shaped recording medium reproducing device to which the stylus force adjustment mechanism of the present invention is applied, and FIGS. A front view and a side view of an example of the pick-up mechanism used are shown.

In FIGS. 1 and 2, a disk-shaped recording medium (hereinafter referred to as a disk) 1 is inserted into the playback device 2 through the opening 2a while being housed in a case 1a, and by pulling out the case 1a, the playback device 2 is inserted into the playback device 2. It is placed on the turntable 3 inside. Next, when playback is started by pressing a button, etc., the disk 1 rotates integrally with the turntable 3 as the motor 4 is driven, and the signal recording surface of the disk 1 is picked up by the pick-up mechanism 7 running on a pair of guide rails 5 and 6. The signal recorded on 1b is reproduced. Pick-up mechanism 7
The pick-up cart cartridge 7a and the carrier 7
The cartridge 7a is removably assembled into the carrier 7b. A shaft 7as, which is the center of rotation of the cantilever 7al, is rotatably held in the case 7ac of the cartridge 7a. 7ap is a needle tip, which is fixed to the tip of the cantilever 7al.

The guide rails 5 and 6 are arranged facing each other at a predetermined distance from each other on the upper surface of the chassis 8 in the reproduction device 2, and the two grooved rollers 9 and the non-grooved rollers 10 provided on both sides of the carrier 7b They are rotatably supported on guide rails 5 and 6, respectively. The stylus tip 7ap of the pick-up cartridge 7a must always be in contact with the signal recording surface of the disk 1 with a predetermined stylus pressure, and for this reason, the height of the carrier 7b relative to the chassis 8 is adjusted by the method described later. . Note that the rotating surface of the turntable 3 is adjusted in advance so that it is parallel to the chassis 8.

Here, the grooveless roller 10 rolling on one of the guide rails 6 is pivotally supported by a U-shaped shaft support member 11, as shown in FIGS. It is integrally formed with the other end of an elastic piece 13 whose one end is fixed to the side collar 12 using a screw 12a. A nut 14 is fixed to the upper part of the elastic piece 13, and an adjusting screw 15 is threaded through the nut 14. This adjustment screw 15 is for adjusting the needle pressure of the needle tip 7ap during regeneration, and its lower end is in contact with the collar 12 so that the height of the carrier 7b with respect to the roller 10 can be directly adjusted. It has been stopped.

Therefore, the height of the carrier 7b on the guide rail 5 side relative to the chassis 8 can be adjusted by changing the screwing amount of the adjustment screw 15.
For example, by increasing the screwing amount of the adjustment screw 15, the distance between the elastic piece 13 and the flange 12 becomes larger, so that the height of the carrier 7b relative to the chassis 8 becomes lower. Conversely, by reducing the screwing amount of the adjustment screw 15, the distance between the elastic piece 13 and the flange 12 becomes smaller, so that the carrier 7
The height of b relative to the chassis 8 can be increased.

Next, adjustment of the stylus pressure of the pick-up cartridge 7a will be explained with reference to FIG. FIG. 5 shows an exploded perspective view of an embodiment of the stylus pressure adjusting cartridge of the present invention.

In FIG. 5, the stylus force adjustment cartridge 17a is
Instead of the cantilever 7al shown by the dashed line,
The shaft 17as of the rotating piece 17al shown by a solid line is rotatably supported on the cartridge case 17ac about the same rotation center as the cantilever 7al. This rotating piece 17al is made of a conductive member, and the length from the center of its rotating shaft 17as to the tip is from the center of the rotating shaft 7as of the cantilever 7al, which is optimal during reproduction, to the signal recording surface of the disk 1. It is made to match the distance h.

In this way, the rotating piece 1 is replaced with the cantilever 7al.
The adjustment cartridge 17a assembled with the adjustment cartridge 7al is assembled into the pick-up mechanism 7, and the disk 1 is placed at a position higher than the thickness of the disk 1, that is, the upper surface of the periphery is properly installed in the playback device 2 during normal playback. The carrier 7b is moved to the peripheral edge of the turntable 3 which is fixed so as to be at the same height as the signal recording surface 1b (hereinafter referred to as the signal recording surface including the upper surface of the peripheral edge of the turntable which is fixed as described above).

Here, in order to check whether the rotating piece 17al has come into contact with the disk 1, a lamp 18 and a power source 19 are connected in series between the rotating piece 17al and the disk 1, as shown by the dashed line in FIG. A connection circuit 20 is connected.

However, at the time of starting the adjustment, the height of the carrier 7b is set sufficiently higher than the target height by reducing the screwing amount of the adjustment screw 15, so the rotating piece 1
7al does not come into contact with the turntable 3, and therefore electrical continuity between the rotating piece 17al and the turntable 3 cannot be obtained.
Lamp 18 does not light up.

Next, the height of the carrier 7b is gradually lowered by increasing the screwing amount of the adjusting screw 15. Perform this operation slowly and carefully. And the rotating piece 17al
When the lower end of comes into contact with the turntable 3,
The rotating piece 17al and the turntable 3 are electrically connected to each other, and as a result, the lamp 18 is lit. By lighting this lamp 18, it is confirmed that the distance between the rotation center of the cantilever 7al and the turntable 3 has been adjusted to the predetermined distance h, so the screwing in of the adjustment screw 15 is stopped and the height of the carrier 7b is adjusted. Finish the adjustment.

Furthermore, when the height adjustment of the carrier 7b is completed,
Although the carrier 7b may not be parallel to the chassis 8, this does not prevent successful regeneration and the inclination of the carrier 7b does not pose a problem. Furthermore, even when the carrier 7b is tilted with respect to the chassis 8, the rotating piece 17al, which is rotatably supported by the cartridge case 17ac, always hangs down in the vertical direction due to its own weight. . Therefore, as long as the turntable 3 is horizontal, the distance between the adjusted rotational center position of the cantilever 7al and the signal recording surface 1b of the disk 1 on the turntable 3 is accurately set to a predetermined value h. be able to.

In this way, the reproducing device 2 having the above-mentioned configuration can vary the height of the carrier 7b by adjusting the adjustment screw 15, and thereby can extremely easily adjust the height of the cantilever 7al.
Since the distance between the rotation center of the disk 1 and the disk 1 can be set to a predetermined value h, the needle tip 7 can be
The inclination angle of the cantilever 7al when ap contacts the signal recording surface 1b of the disk 1 can be set to an appropriate value. Therefore, during reproduction, the stylus tip 7ap of the pick-up cartridge 7a can be brought into contact with the signal recording surface of the disk 1 with a predetermined stylus pressure, and a highly accurate reproduction signal can be obtained.

Furthermore, the playback device 1 having the above configuration can easily and accurately adjust the stylus force by using the stylus force adjustment cartridge 17a to which the conductive rotating piece 17al is attached instead of the cantilever 7al.

Here, by adjusting the height of the carrier 7b to which the cartridge 17a for adjusting stylus pressure is attached at the position where the rotating piece 17al contacts the signal recording surface 1b, the cantilever 7al can be used in place of the cartridge 17a for adjusting stylus force. Installed cartridge case 1
The reason why a predetermined stylus pressure can be obtained when the 7ac is attached to the carrier 7b will be explained.

The cantilever 7al is configured to be biased toward the disk when fixed to the cartridge case 17ac by a suspension (not shown) provided on the shaft 7as. That is, the biasing force generated by this suspension becomes the stylus pressure when the stylus tip 7ap comes into contact with the disk 1. This biasing force changes depending on the position where the shaft 7as of the cantilever 7al is adhesively fixed to the cartridge case 17ac, but when assembling the pick-up cartridge 7a, a predetermined stylus pressure can be obtained using an electronic balance or the like in a properly installed state. It has been assembled and adjusted so that

Next, referring to FIG. 3, the state in which the pick-up cartridge cartridge 7a is installed at the proper position will be described. Now, assume that the state shown in FIG. 3 is the state in which the pick-up cartridge 7a is properly installed. In this state, the shaft 7as and the needle tip 7
The position where ap contacts the signal recording surface 1b and the axis 7as
Pay attention to the right triangle formed by the point where the line drawn vertically from the point intersects with the signal recording surface 1b. If this right triangle deviates from the shape shown in FIG. 3, the stylus pressure will change from its proper value. Now, signal recording surface 1b
Since it is the surface of the disk 1 placed on the turntable 3, it can be considered to be fixed, and the length of the cantilever 7al is also constant. Therefore, it is the axis 7as that destroys the above triangular shape.
This is the case when the height position h from the signal recording surface 1b is changed. If h is longer than the appropriate value, the stylus pressure will be lighter, and if h is shorter than the appropriate value, the stylus pressure will be heavier. That is, the stylus pressure can be adjusted by changing the height position between the signal recording surface 1b and the shaft 7as.

Therefore, by attaching the stylus force adjustment cartridge 17a to the carrier 7b and fixing the carrier 7b at a position where the rotating piece 17al, which has been selected to have the appropriate length as described above, comes into contact with the recording signal surface 1b, the stylus pressure adjustment cartridge 17a can be fixed. Carrier 7b replaces pressure adjustment cartridge 17a
When installing the pick-up cart cartridge 7a,
The above-mentioned triangle is uniquely determined, and therefore the stylus pressure becomes a predetermined value.

In the above embodiment, the adjustment screw 15 was configured to be screwed into the nut 14 that is integrated with the shaft support member 11, but for example, the adjustment screw 15 is screwed and inserted into the flange 12 of the carrier 7b from below, and the screw It is also possible to have a configuration in which the distal end portion of the elastic piece 13 or the shaft support member 11 is brought into contact with and locked from below.

Further, in the above embodiment, the height of the carrier 7b is adjusted on the guide rail 6 side, but
The height may be adjusted on the guide rail 5 side.

As described above, according to the present invention, even when the height of the cartridge case is changed to adjust the stylus pressure,
Since the rotating piece always hangs vertically due to its own weight, accurate stylus pressure adjustment is always possible regardless of the inclination of the cartridge case.Furthermore, the stylus pressure can be adjusted based on the presence or absence of continuity of the rotating piece. It has the advantage that there is no risk of erroneous investigation.

[Brief explanation of the drawing]

1 and 2 are a schematic perspective view and a schematic vertical cross-sectional view, respectively, showing the internal structure of an example of a disk-shaped recording medium reproducing device to which the stylus force adjustment mechanism of the present invention is applied, and FIGS. A front view and a side view of an example of the pickup mechanism used, and FIG. 5 is an exploded perspective view of an example of the stylus force adjustment mechanism of the present invention. 7ac, 17ac... Cartridge case, 7al... Cantilever, 15... Adjustment screw, 17a... Cartridge for adjusting stylus pressure, 17al... Rotating piece.

Claims (1)

[Claims] 1. A conductive rotating piece whose length from the center of rotation to the tip is equal to the appropriate distance from the center of rotation of the reproduction cantilever to the signal recording surface of the recording medium; In place of the cantilever, there is provided a stylus force adjustment cartridge rotatably supported on a cartridge case with its rotation center aligned with the rotation center of the cantilever, and a stylus force adjustment cartridge that supports the stylus force adjustment cartridge and extends over the guide member. a height position adjustment mechanism configured to adjust the height position of the stylus force adjustment cartridge with respect to the recording medium by varying the height position of the carrier to be transferred with respect to the guide member; When the height position adjustment mechanism changes the height of the stylus pressure adjustment cartridge on the surface, the tip of the rotary piece contacts the signal recording surface at a position where appropriate stylus pressure is obtained, and the corresponding contact is made. A stylus force adjustment mechanism comprising a detection means capable of detecting electrical continuity between the rotating piece and the signal recording surface.