JPH0138721Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing device for a tone arm, and particularly to improvements in knife edge type and pivot type bearing devices.

Conventionally, in a tone arm in which the vertical rotation axis of the tone arm was constructed with a knife edge type bearing,
As shown in Fig. 1, the fulcrum P between the knife edge shaft 11 and the knife edge bearing 12 is likely to move due to the so-called drag force in which the tone arm is pulled as the record rotates, so the movement of the fulcrum of the tone arm affects the playback signal. This results in modulation, causing frequency cross-modulation distortion and phase modulation distortion, and also has drawbacks such as poor housing characteristics and adverse effects on wow and flutter.

In addition, in a knife edge type bearing, a device such as JP-A-50-67107 that prevents the movement of the fulcrum is known, but by pressing the rotation shaft with a locking part from above, the fulcrum can be prevented from moving. Since it is intended to prevent forward movement, the drag force is suppressed from a direction perpendicular to the direction in which it is generated, so a sufficient prevention effect cannot be obtained, and high processing accuracy is required. There were drawbacks such as poor machining accuracy that adversely affected the movement of the tone arm itself.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tone arm bearing device that eliminates the above-mentioned drawbacks.

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

In the figure, 1 indicates an arm pipe, 1a indicates the head shell side, and 1b indicates the main weight side. Reference numeral 2 refers to the entire bearing, and this structure itself is supported horizontally rotatably on a horizontally rotatable bearing member (not shown).

Figure 2 shows an example of the knife edge type.
4 represents a knife edge shaft, and 4 represents a knife edge bearing portion (vertical rotation bearing member). The knife edge shaft 3 is fixed to the arm pipe 1, and the arm pipe 1 swings around the ridgeline of the knife edge shaft 3.

The bearing part 2 is provided with a movement prevention means 5 for preventing movement of the bearing fulcrum of the vertical rotation shaft due to the drag force, and the movement prevention means 5 is located near the center of the cross section perpendicular to the longitudinal direction of the tone arm. provided. As shown in FIG. 2, this movement prevention means 5 is composed of a pivot 6 (movement prevention member) that makes point contact and a pivot holder 7 (receiving part). 1, a substantially L-shaped pivot 6 protruding from the knife edge bearing 4 is extended to the notch 8, inserted into the notch 8, and inserted into the arm pipe side. The cartridge side is brought into contact with the rear wall of the notch 8, that is, the pivot pedestal 7 provided in a section perpendicular to the longitudinal direction of the tone arm, to prevent the tone arm from moving forward. As a result, the arm pipe 1 is prevented from moving toward the cartridge, and movement of the fulcrum due to the drag force generated as if being pulled toward the cartridge is prevented.

As is clear from the drawings, the contact point between the pivot 6 and the pivot pedestal 7 is aligned with the axis of the tips of the knife edges 3, 3, and is also located on the longitudinal axis of the arm pipe 1. Incidentally, in the case of point contact, the pivot may be provided on the arm pipe side and the pivot pedestal may be provided on the knife edge bearing portion side.

FIG. 3 shows an example in which the pivot pedestal 7 is formed flat. With this configuration, the tone arm can be easily removed from the bearing part, and also,
There is no need to improve the machining accuracy of the contact point, and the tone arm can be replaced.

The need to provide the above-mentioned fixing means on the bearing of the tone arm is not limited to the knife edge type or pivot type, but applies to all types of bearing devices in which the shaft fulcrum may move due to drag force. Of course, the invented bearing device can be used for all of these.

According to the tone arm bearing device of the present invention, it is possible to prevent the bearing fulcrum from moving due to the drag force in the direction in which the drag force is generated, and the movement preventing means consists of a pivot and a pivot pedestal, and the contact point Since the axis line coincides with the axis of the bearing, the vertical pivot point is clear, and even when the tone arm traces the record, the vertical pivot point does not move due to the drag force, resulting in the following effects. .

(a) Frequency cross modulation distortion and phase modulation distortion can be reduced.

(b) Howling characteristics are improved.

(c) Good wow/fluttering.

(d) Since the tone arm does not move forward even in the knife-edge type bearing portion, the tone arm does not require more weight than necessary, so the tone arm can have a small equivalent mass.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged view for explaining the movement of the fulcrum in a knife edge type bearing device in a conventional tone arm, and FIGS. 2 and 3 show an embodiment of the tone arm bearing device according to the present invention. FIG. 2 is a partially cutaway perspective view, and FIG. 3 is a sectional view showing another configuration example. DESCRIPTION OF SYMBOLS 1... Arm pipe, 2... Bearing part, 3... Knife edge shaft, 4... Knife edge bearing part, 5...
...Fixing means, 6... Pivot, 7... Pivot cradle, 8... Notch.

Claims (1)

[Scope of utility model registration request] A vertical rotation bearing member configured to be horizontally rotatable, a movement prevention member provided on the vertical rotation bearing member and extending to the center of vertical and horizontal rotation, and a cross section perpendicular to the longitudinal direction of the tone arm. 1. A bearing device for a tone arm, comprising: a receiving portion provided on the tone arm, the distal end of the movement preventing member being brought into point contact with the receiving portion of the tone arm from the cartridge side.