JP3213405U - Tone arm without tracking error - Google Patents

Abstract

Provided is a tone arm which does not cause a tracking error in which a rotation angular velocity of a head shell is halved of a rotation angular velocity of a tone arm by an orthogonal gear mechanism. When a point target position C of A with respect to a spindle axis A and an axis B, O of a head shell 7 is arranged on a circle Y having a radius AO centered on a rotation fulcrum O of a tone arm 2, Since ACB is a half of ∠AOB, once the cantilever is set in the tangential direction of the record groove where the record needle contacts by setting the rotational angular velocity of the head shell to one half of the rotational angular velocity of the tone arm. Thereafter, the tracking error angle is always zero. [Selection] Figure 1

Description

  In the present invention, when reproducing the analog record, the cantilever can always be placed on the tangent line of the record groove where the record needle is in contact with the rotational angular velocity of the head shell by halving the rotational angular velocity of the tone arm. The present invention relates to a tone arm that does not cause a tracking error.

  When a one-fulcrum pivoting tone arm called a universal type pivots from the outside to the inside of the record board, the direction of the cantilever causes an angle error that causes a tracking error with respect to the tangent line of the record groove with which the needle tip contacts. As countermeasures against this, a number of mechanisms have been devised so far, but many of them are theoretically incomplete or cannot be put into practical use due to problems in the mechanism or structure.

JP-A-9-54901

Utility model literature

Utility model document 1

Sho 61-68520

Utility model document 2

Sho 61-95042

Utility Model Reference 3

Sho 62-2954

Utility Model Reference 4

Sho62-176617

  In order to realize a tone arm that does not cause a tracking error, a mechanism that theoretically does not cause a tracking error is required.

  The present invention is based on the theorem that in Euclidean geometry, the circumferential angle with respect to the arc is one-half of the central angle, and the rotational angular velocity of the head shell is divided into two by the orthogonal gear mechanism. It is realized by making it one.

  As described above, once the cantilever is set in the tangential direction of the record groove by setting the rotational angular velocity of the head shell to one half of the rotational angular velocity of the tone arm using the orthogonal gear mechanism, the tracking error angle is always set thereafter. It becomes 0 degrees and no tracking error occurs.

It is a top view which shows the outline | summary of one Example of this invention. It is a side view of the tone arm which shows the outline | summary of one Example of this invention.

  The tone arm shaft core gear is fixedly attached to the tone arm pedestal at a rotational fulcrum coaxial position of the tone arm. The tone arm tip gear is attached to the tone arm tip by a mechanism that freely rotates in the horizontal direction. Further, the tone arm shaft core gear and the tone arm tip gear are interlocked with each other through a shaft connecting the orthogonal gear and the orthogonal gear. Therefore, as the tone arm rotates, the tone arm tip gear rotates according to the number of teeth of the tone arm shaft core gear and each orthogonal gear. Here, by setting the rotation ratio of the tone arm shaft core gear and the tone arm tip gear to 2: 1, the rotation angular velocity of the head shell interlocked with the tone arm tip gear becomes one half of the rotation angular velocity of the tone arm. . In addition, the distance from the tone arm rotation fulcrum to the record center, that is, the spindle axis, and the center of the tone arm axis gear, that is, the distance from the tone arm rotation fulcrum to the tone arm tip gear center are made equal, and the tone arm tip gear Connect the head shell to the head shell, and attach the cartridge so that the tip of the cantilever, that is, the tip of the record needle, is on the pivot axis of the head shell, and then set the direction of the cantilever once to the direction of the record groove where the record needle contacts Then, since the cantilever is always on the tangential direction of the record groove where the record needle contacts, the tracking error angle becomes 0 degree and no tracking error occurs.

  Hereinafter, an embodiment will be described with reference to the accompanying drawings. The bevel gear 5a is fixed to the tone arm pedestal 12 at the rotation fulcrum position O of the tone arm 2, and interlocks with the bevel gear 6a via the bevel gear 5b, the shaft 4, and the bevel gear 6b. The head shell 7 is connected and fixed to the bevel gear 6a. Further, the tip of the cantilever 9, that is, the tip of the record needle 10 is on the bevel gear 6a center, that is, on the vertical line of the head shell rotation axis B. Further, the distance from the tone arm rotation fulcrum O to the spindle axis A is set equal to the distance from the tone arm rotation fulcrum O to the large-diameter pulley center B.

  The point C is on the extension line of the line segment AO, and the line segment AO = the line segment CO. Since the center of the record, i.e., the spindle axis A, and the center of the bevel gear 6a, i.e., the tip B of the record needle 10, and the point C lie on a circle Y centered on O and having a line segment AO as a radius, It is a half of Kakuno AOB.

  Therefore, by setting the rotation ratio of the bevel gear 5a and the bevel gear 6a to 2: 1, the center line of the head shell 7, that is, the center line of the cartridge 8, that is, the direction of the cantilever 9 is on the line segment BC, and the angle ∠ABC is on the diameter. Since it is a circumferential angle and a right angle, the cantilever 9 is on the tangential direction BC of the record groove with which the record needle 10 contacts.

  As described above, the tracking error angle is 0 degree, and no tracking error occurs.

DESCRIPTION OF SYMBOLS 1 Record or turntable 2 Tone arm 3 Balance weight for record needle pressure adjustment 4 Shaft connecting gears 5b and 6b 5a Gear concentric with rotation axis of tone arm 5b Orthogonal gear of gear 5a 6a Rotation of head shell Gear 6b Gear 6a orthogonal gear 7 Shaft shell 8 Cartridge 9 Cantilever 10 Record needle 11 Bearing 12 Tone arm pedestal O Tone arm pivot axis, center of gear 5a A Center of record , The center of the turntable, the axis of the spindle B, the axis of rotation of the gear 6a, the axis of rotation of the head shell, the vertical line C of the tip of the cantilever, that is, the tip of the record needle, on the extension of the line segment AO , Line segment AO = line segment CO
A virtual circle centered on Y 2 O and having a line segment AO as a radius. A, B, and C are located on the circle Y.

Claims (1)

In the tone arm with one fulcrum rotation used for analog record playback,
(1) Install and fix the tone arm shaft core gear so that it does not rotate with respect to the pedestal of the tone arm on the same axis of the tone arm rotation fulcrum.
(2) The tone arm tip gear is connected to the tone arm tip by a mechanism that freely rotates in the horizontal direction,
(3) Connect the orthogonal gear of the tone arm shaft core gear and the orthogonal gear of the tone arm tip gear with a shaft,
(4) The head shell carrying the cartridge is connected so that the tip of the cantilever, that is, the tip of the record needle is on the vertical line of the rotation axis of the tone arm tip gear so as to interlock with the tone arm tip gear,
(5) The tone arm is positioned at the center of the tone arm axis gear, that is, the distance from the rotation axis of the tone arm to the axis of the tone arm tip gear is equal to the distance from the rotation fulcrum of the tone arm to the spindle axis. Deploy,
(6) Here, by setting the rotation ratio of the tone arm shaft core gear and the tone arm tip gear to 2: 1,
(7) Once the rotational angular velocity of the head shell is half of the rotational angular velocity of the tone arm and the direction of the cantilever is set on the tangent line of the record groove where the record needle contacts, The tracking error angle is always 0 degree because it is tangential,
A tone arm that does not cause tracking errors due to the above structure and mechanism.

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