JPS632964Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a rotation mechanism for a tone arm in a record player, and in particular, an auto-read system for a tone arm using a tone arm drive member that is reciprocated by a heart-shaped cam. In a device that performs in-auto lead-out, the purpose is to smoothly convert the forward movement of the tone arm driving member to the backward movement.

The tone arm driving member is caused to reciprocate in response to the rotation of the cam body having a heart-shaped cam, thereby performing tone arm auto lead-in (moving the tone arm from the rest position to the playing position) and auto lead-out (tone arm movement). A rotary mechanism for a record player configured to move the arm from the playing position to the rest position was developed, for example, in the
9169, JP-A-55-153171, etc.

That is, in such a tone arm rotation mechanism, the cam follower pin 1a provided on the tone arm driving member 1 engages with the bottom portion 3a of the heart-shaped cam 3 provided on the cam body 2 in the stopped state. (See Figure 1). As is well known, a gear part 4 is formed on the outer periphery of the cam body 2 , and in a stopped state, a gear part 7 provided on the turntable shaft 6 is located in a notch 5 on the outer periphery. In the auto lead-in/auto lead-out state, as is well known, the gear portion 4 of the cam body 2 and the turntable shaft 6
The gear portions 7 provided in the cam member 7 are in mesh with each other, and the cam body 2 is rotated in response to the rotation of the turntable shaft 6. In response to the rotation of the cam body 2 , the tone arm driving member 1 is guided by the guide hole 1b and the guide pin 8 and is caused to make a reciprocating movement (in the illustrated embodiment, a linear reciprocating movement). Then, a tone arm lever (not shown) is rotated to perform automatic lead-in and automatic lead-out operations of the tone arm.

By the way, considering the state at the time of transition in which the tone arm driving member 1 moves forward from the position shown in FIG. 1 to the position shown in FIG. top of cam 3
There will be a sudden change in b. Therefore, the cam follower pin 1a could not easily escape from the top 3b of the heart-shaped cam 3, making it difficult to make a smooth transition. Therefore, in the present invention, a biasing means (stepper spring) 9 is provided which comes into contact with the tone arm driving member 1 and biases this member 1 in the backward movement direction at the time of such conversion. . The stepper spring 9 is wound around a pin 10 provided on the board. 11 is a stopper pin.

According to the present invention described above, when the tone arm driving member changes from forward movement to backward movement,
With an extremely simple configuration that includes a biasing means that biases the tone arm drive member in the backward movement direction, such a transition can be performed smoothly, and auto lead-in/auto lead-out operations can be reliably achieved. It is possible.

In addition, even in the conventional type, a means is provided for constantly biasing the tone arm driving member so that the cam follower pin traces the cam surface reliably, and this biasing means is used at the time of changeover. As a result, the tone arm driving member was urged in the backward movement direction. However, the purpose of this biasing means is to make the cam follower pin trace the cam surface, and because the biasing force is weak, it is difficult to make the cam follower pin escape from the top of the heart-shaped cam at the time of changeover. It cannot be a sufficient urging force. The present invention can reliably achieve such escape by providing means for biasing the tone arm driving member only at the time of change.

[Brief explanation of the drawing]

The drawings all show the rotating mechanism of the tone arm according to the present invention; FIG. 1 shows the tone arm in a stopped state, and FIG. 2 shows it in a state of change. DESCRIPTION OF SYMBOLS 1... Tone arm drive member, 1a... Cam follower pin, 2 ... Cam body, 3... Heart-shaped cam,
9...Biasing means.

Claims (1)

[Scope of utility model registration request] a cam body having a heart-shaped cam; and a tone arm driving member that has a cam follower pin that engages with the heart-shaped cam and rotates the tone arm by reciprocating in response to rotation of the cam body; and biasing means that comes into contact with the tone arm driving member when the tone arm driving member changes from the forward motion to the backward motion, and the biasing means causes the tone arm to be driven during the transition. A tone arm rotation mechanism characterized by biasing a tone arm member in a backward movement direction.