JPH0119205Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing device for a tone arm, and more particularly to a bearing device suitable for application to knife edge type and pivot type bearing structures.

Conventionally, in the knife edge type bearing structure of a tone arm, as shown in FIG. 1, the fulcrum P between the knife edge shaft 11 and the knife edge bearing 12 moves due to the so-called drag force in which the tone arm is pulled as the record rotates. This causes the generation of frequency cross-modulation distortion and phase modulation distortion, and also has drawbacks such as poor howling characteristics and adverse effects on wow and flutter.

On the other hand, in a pivot type bearing structure, etc., the fulcrum is provided with an appropriate backlash in order to obtain appropriate sensitivity, so it is affected by the same drag force as described above.

Therefore, we previously proposed a bearing device that prevents drag force by providing a pivot on the base side and a pivot cradle on the tone arm side (Utility Model Application No. 56-25316), but in this case, There was a problem that setting the bearing fulcrum was extremely difficult.

An object of the present invention is to provide a tone arm bearing device that improves the above-mentioned points.

The structure of the present invention will be explained together with its embodiments based on the drawings shown in FIG. A shaft support 4 of the tone arm 3 is supported by a bearing mechanism 5 from both sides of the arm bracket 2.
As the bearing mechanism 5, a pivot bearing mechanism is used in the embodiment, but it goes without saying that it may also be of a knife edge type.

In the present invention, a knife edge 61, which is provided on the shaft support 4 of the tone arm 3 and whose tip 62 coincides with the axis 5c of the double bearing mechanism 5 and faces toward the cartridge side H, and a knife edge 61 that slides onto the arm bracket 2 are provided. a pivot 7 which is movably provided so that its tip 71 can come into contact with the tip 62 of the knife edge 61 and whose contact point P coincides with the axis 3c of the tone arm 3; 7 resiliently abut against the knife edge tip 62.

To explain the above-mentioned structure in detail, a notch 22 is formed in the lower surface of the arm bracket 2, and a pipe holder 33 of the arm pipe is accommodated in this so as to be perpendicular to the axis 5c. This pipe holder 33 has a shaft hole 34 that corresponds to the insertion hole 23 formed on both sides of the arm bracket 2, and the support shaft 6 inserted through the insertion hole 23 is inserted and fixed therein. , pivot bearing member 5
It is held at 5,56. Note that cylindrical weights 57 are attached to the support shaft 6 so as to be located on both sides of the pipe holder 33. A knife edge 61 is formed in the center of the support shaft 6 so that the tip 62 faces the cartridge side H, and the tip 62 is aligned with the axis 5c, and the tip 62 is slightly flat. formed on the surface,
This ensures proper contact with the pivot 7. The pipe holder 33 is provided with a recessed cutout 35 with an opening on the top surface, and the knife edge 61
is exposed in this recessed notch 35.
A support member 9 is attached to the upper wall surface of the notch 22 of the arm bracket 2, and the support member 9 is adapted to fit loosely into the recess 35. Further, this support member 9 is provided with a side hole 91 in which the pivot 7 can slide, and its tip 71 is connected to the tip 6.
It is designed to come into contact with 2. As described above, the contact point P is arranged to coincide with the axis 3c. The pivot 7 is elastically pressed by a spring means 8 inserted into the horizontal hole 91, so that it comes into contact with the tip 62 elastically.
A viscous substance such as silicone grease is placed in the horizontal hole 91 to brake the movement of the pivot and spring means. Incidentally, reference numeral 82 is a spring seat screw, which allows adjustment of the contact elastic force of the spring means 8. 93 is a mounting screw for the support member 9.

Next, an operation example will be described. The tone arm 3 rotates horizontally when the rotating shaft 1 rotates, but since it is supported by the bearing mechanism 5, it can swing up and down about the axis 5c. ing. Generally, the shaft supported by the bearing mechanism 5 has a certain amount of play, but when the so-called drag force, in which the tone arm 3 is pulled as the record rotates, occurs, the knife edge 61 Since the tip 62 of the pivot 7 is in contact with the tip 71 of the pivot 7, the drag force is regulated, and the contact is not fixed but is caused by the spring means 8.
Since it is elastic, it is possible to make a reasonable restriction, and the elastic contact force can be easily adjusted. Further, the contact point P is located at the intersection of the axis 5c of the bearing mechanism 5 and the axis 3c of the tone arm 3, and there is no possibility of affecting the operation of the tone arm 3 in any way.

According to the tone arm bearing device of the present invention, the knife edge is provided on the shaft portion of the tone arm, the tip of which is aligned with the axis of the bearing mechanism and faces the cartridge side, and the knife edge is provided on the arm bracket so as to be slidable thereon. a pivot whose tip is able to come into contact with the tip of the knife edge and whose point of contact is aligned with the axis of the tone arm; and a pivot which elastically comes into contact with the tip of the support shaft. Since it is equipped with a spring means for bringing the knife edge into contact with the tip, drag force is accurately prevented even if there is some play in the bearing device for supporting the shaft portion of the tone arm. The contact force can be adjusted arbitrarily and has the advantage that it does not affect the operation of the tone arm in any way.

[Brief explanation of the drawing]

Fig. 1 is a partially enlarged view for explaining the movement of the fulcrum in a conventional knife edge type bearing device, Figs. 2 to 5 show an embodiment of the tone arm bearing device according to the present invention, and Fig. 2 shows the main parts. 3 is a vertical sectional view of the main parts, 4 is a horizontal sectional view of the same,
FIG. 5 is a sectional view taken along the line A--A in FIG. 4. 1... Rotating shaft, 2... Arm bracket, 3...
...Tone arm, 3c...Axis line, 4...Axis support,
5... Bearing mechanism, 5c... Axis line, H... Cartridge side, 61... Knife edge, 62... Tip,
7...Pivot, 71...Tip, 8...Spring means.

Claims (1)

[Scope of Claim for Utility Model Registration] A bearing device for a tone arm in which a shaft support of a tone arm is supported by a bearing mechanism from both sides of an arm bracket fixed to a rotating shaft, the shaft support of the tone arm mentioned above. a knife edge provided on the arm bracket, the tip of which is aligned with the axes of the two bearing mechanisms and facing the cartridge side; and a knife edge that is slidably provided on the arm bracket so that the tip can come into contact with the tip of the knife edge. and a pivot whose contact point coincides with the axis of the tone arm, and spring means for elastically bringing the pivot into contact with the tip of the knife edge. Tone arm bearing device.