JPS6117522Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rest position control device that prevents a tone arm returned to a rest by an auto-return device in a record player from being displaced when the tone arm is lowered to the rest.

Conventional auto-return devices for record players have a structure in which the tone arm is placed on the rest by rotating the rotation shaft of the tone arm by a certain angle using an idler or belt from a drive source, etc. However, this conventional structure has the drawback that the idler or belt slips due to mechanical transmission, and therefore the return operation ends with the tone arm not placed on the arm rest.

In consideration of this point, the present invention emits an electric signal just before the tone arm reaches the rest position, and this electric signal gives rotational movement to the tone arm for a certain period of time, so that the tone arm is always at the normal rest position. The purpose is to prevent conventional malfunctions.

An example of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an external perspective view of an example of the tone arm structure. As before, the tone arm 1 is provided with a rotating shaft 2 in the vertical direction, a cartridge shell 3 is provided at one end, and a balance weight 4 is provided at the other end. 5 indicates a cartridge. A fan-shaped slit plate 6 is attached to the lower end of the rotating shaft 2, and a slit 7 is formed in the slit plate 6. A detection element consisting of a light emitting element 8 and a light receiving element 9 is provided in a direction orthogonal to a certain point of the trajectory of the slit 7 as the slit plate 6 rotates, and the light beam emitted from the light emitting element 8 is normally blocked by the slit plate 6. However, when the light coincides with the slit 7, the light is detected by the light receiving element 9.

As shown in Fig. 2, the positional relationship between the detection element and the armrest is set at a constant angle (θ°) from the tone arm rotation axis, with the position of the armrest 10 being the rotation origin (0°) of the tone arm 1. The light emitting element 8 and the light receiving element 9 are provided in corresponding positions. That is, the tone arm 1 performs a return operation by the auto-return mechanism, but just before it approaches the armrest 10, that is, at the constant angle (θ°) position, the light beam from the light emitting element 8 passes through the slit 7 and reaches the light receiving element. It is configured to reach 9.

As shown in FIG. 2, the armrest 10 is formed with a concave mounting portion 10a matching the diameter of the tone arm 1, a stopper 10b for preventing return rotation of the tone arm 1, and a lock piece 10c. The stopper 10b is provided so that the axis of the tonearm 1 coincides with the center of the armrest 10 when the tonearm 1 comes into contact with the stopper 10b.

Next, regarding the electric control section including the light receiving element 9, the third
To explain with reference to the figure, the output of the light receiving element 9 is waveform-shaped by a waveform shaping circuit 12, and the output of the waveform shaping circuit 12 is supplied to a monostable multivibrator 13 as a trigger signal. The monostable operation time width (time constant) of the monostable multivibrator 13 is set to be larger than the time width for the tone arm 1 to reach the rotational origin (0°) from the rotational position (θ°). When the operation of the monostable multivibrator 13 ends, the output control circuit 14 is driven. This output control circuit 14 is configured to issue a signal for ending the return operation of the tone arm 1, and at the same time issue a signal for causing the tone arm 1 and armrest 10 to lower. 15
16 indicates a return end output terminal, and 16 indicates a descent start output terminal.

Next, the operation of the device of the present invention will be explained with reference to FIG. In the figure, the rotation angle of the tone arm 1 is set on the vertical axis, the time is set on the horizontal axis, and the return of the tone arm 1 is set based on a line connecting the rotation center point of the tone arm 1 and the center of the armrest 10. It represents the operating state of the motion and electric circuit parts.

When the record performance ends, the tone arm 1 rises and starts a return operation, at which time the opening angle of the tone arm 1 is set to (α°). When the tone arm 1 rotates over time and reaches a certain angle (θ°), that is, when the slit 7 reaches the position where the light emitting element 8 and the light receiving element 9 are provided, an output is output to the light receiving element 9. occurs, and the monostable multivibrator 13 operates, and the rotational movement of the tone arm 1 ends before the monostable multivibrator 13 ends its operation. In other words, tone arm 1
Even if it comes into contact with the stopper 10b of the armrest 10, the return operation does not end immediately.

After a certain period of time t has elapsed since the tone arm 1 came into contact with the stopper 10b, the operation of the monostable multivibrator 13 ends. Then, a stop signal for the auto-return operation is issued from the output control circuit 14 and the return operation is completed, and a lowering signal is issued and the lowering operation is started, and the tone arm 1 is placed on the concave mounting portion 10a of the armrest 10. That will happen.

As described above, according to the present invention, since it is configured as described above, the auto-return operation does not end and the tone arm lowering operation does not occur unless the tone arm reaches the armrest. After the tone arm contacts the stopper of the armrest and a certain period of time elapses, the auto-return operation ends and the tone arm starts lowering. Therefore, the return operation is never completed without the tone arm being placed on the armrest, which increases the reliability of this operation and has the effect of improving the performance of the product.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view showing an example of the tone arm mechanism, Fig. 2 is a schematic diagram showing the positional relationship between the detection element and the armrest, Fig. 3 is a block diagram showing an example of the electric control section, and Fig. 4 FIG. 2 is a diagram for explaining the operation of the present invention. 1...Tone arm, 6...Slit plate, 7...
...slit, 8... light emitting element, 9... light receiving element,
10...Armrest, 10b...Stopper, 1
2... Waveform shaping circuit, 13... Monostable multivibrator, 14... Output control circuit.

Claims (1)

[Scope of utility model registration request] The tone arm has a detecting means for detecting the position of the tone arm before it reaches the arm rest after making a return operation from the performance end position, and a regulating member for regulating further movement of the tone arm after reaching the arm rest, After the detection signal is generated by the detection means, the auto-return operation is stopped after a predetermined time that is longer than the time it takes for the tone arm to reach the armrest from the position detected by the detection means. Tone arm rest position control device.