JPS6127835B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a record detection device that automatically detects the presence or absence of a record on a turntable, the size of the record, etc. in a record player.

As shown in FIGS. 1A and 1B, this type of device has a plurality of sensor pins P disposed radially on the turntable T, which descend against elastic means (not shown) due to the weight of the record. On the other hand,
It has been proposed that the cabinet C has a plurality of optical detection means Ph each consisting of a pair of a light emitting element and a light receiving element arranged so that opening and closing of the optical path is controlled for each sensor pin. Note that FIGS. 1A and 1B show a plan view and a sectional view of the record detection device.

In this case, there is a problem that an optical detection means is required for each sensor pin, resulting in a complicated structure.

The present invention aims to provide a record detection device that can improve this point.

As an embodiment of the record detection device for a player of the present invention, the presence or absence of a record on a turntable,
A method that allows record size detection to be performed extremely simply and reliably at a single location will be described with reference to the drawings.

2A and 2B show a plan view and a sectional view of an embodiment of the record detecting device of the present invention, and FIG. 2C
and D respectively show an enlarged plan view and an enlarged sectional view of the same.

A sensor pin holder H is installed on the turntable T at a position 175 mmφ from the center of the turntable T, and this sensor pin holder H is provided with sensor pins P ₁ and P ₂ that can be moved up and down.
P ₁ and P ₂ are provided with return springs S ₁ and S ₂ respectively between them and the sensor pin holder H.
When a force due to the weight of the record is applied from above, P ₁ and P ₂ descend to block the optical path of optical detection means Ph, which will be described later, and when the force is removed, they return to release the blocking of the optical path.

In the above embodiment, the sensor holder H is fitted into the through hole of the turntable T, and the sensor holder H is attached to the rubber sheet G so that the sensor pins P ₁ and P ₂ can protrude upward from the turntable T.
A through hole with the same diameter is drilled.

Currently, the size of EP records is determined by Japanese Industrial Standards to be 175mm±1mm, so the sensor pin holder H should be placed from the center of the turntable B.
It is placed at a position of 175mmφ so that it can detect whether the record is an EP or something else, but if you want to detect whether it is a record of another size, the record size Needless to say, they are placed at appropriate positions depending on the situation.

Here, the sensor pins P ₁ and P ₂ are connected to the turntable T.
It is located inside and outside the concentric circle r of 175mmφ. The sensor pins P ₁ and P ₂ are further provided at the positions shown in FIG. 2C, where they are arranged on both sides so as not to overlap with respect to the radiation line 1 of the turntable T, or at the positions shown in FIG. 3, where they are arranged on both sides so as to overlap. In the arrangement shown in FIG. 3, it is desirable that the diameter of the sensor pin _P2 be larger than that of the sensor pin _P1 .

A holder _H1 is disposed in the cabinet C at a position 175 mmφ from the center of the turntable T, and the holder _H1 is provided with a light emitting diode D and a phototransistor PT to constitute an optical detection means.

Here, the light emitting diode D and the phototransistor PT are located on the radial line at the center of the turntable T, and the optical path from which the light from the light emitting diode D reaches the phototransistor PT is located between the sensor pins P ₁ and P ₂ . Opening/closing is also controlled by
That is, when the sensor pins P ₁ and P ₂ are in a position lowered by the weight of the record, each rotation of the turntable T passes between the light emitting diode D and the phototransistor PT, and the light from the light emitting diode D is temporarily transmitted. The light is cut off to prevent the phototransistor PT from receiving light. For example, in the case of an EP record, as shown in FIG. 4A, only sensor pin _P1 falls to a position where it can block the optical path due to the EP record's own weight.
In the case of LP record LP, as shown in Figure 4B,
Sensor pins P ₁ and P ₂ are lowered together.

The above light emitting diode D and phototransistor
As shown in Figure 5, PT is connected to the power supply Vcc, and this phototransistor PT controls the on/off of the transistor Tr, and the collector of the transistor Tr is connected to the turntable according to the presence or absence of a record and the size of the record. Output as T rotates
Vx is obtained. This output Vx is shown in FIGS. 6A and B as V ₁ when there is no record, V ₂ when there is an EP record, and V ₃ when there is an LP record. In addition, in Fig. 6 A and B, the sensor pins P ₁ and P ₂ are as shown in Fig. 2 C,
This corresponds to the arrangement example shown in FIG.

Now, if the turntable T is rotated in the state shown in Fig. 2 with no record placed on it, the sensor pins P ₁ and P ₂ are not lowered, so the light from the light emitting diode D is constantly received by the phototransistor PT. At the same time, the transistor Tr is always on, so the output _V1 remains at a low level (0V).

Now, when the turntable T is rotated in the state shown in Fig. 4A with the EP record EP placed on it, the phototransistor PT does not receive light while the light from the light emitting diode D is blocked by the sensor pin _P1 , so the transistor Tr is turned off. Therefore, the output V ₂ becomes high level.

Furthermore, when the turntable T rotates with the _LP record LP placed thereon as shown in _FIG . Since the Tr is turned off, the output _V3 becomes high level. In this case, if _the sensor pins P _{1 and P 2 are arranged} as shown in FIG. Two pulses are obtained per revolution. If the sensor pins P ₁ and P ₂ are arranged as shown in FIG. 3, light will be continuously blocked by the sensor pin P ₂ following the sensor pin P ₁ , and the output V ₃ will be at a high level. It is assumed that this high level period T ₂ is longer than the high level period T ₁ due to the blocking of light by the sensor pin P ₁ .

Therefore, this output Vx is introduced into a record discrimination circuit (not shown), where the presence or absence of a record and the record size can be detected. Output Vx
If Vx does not reach a high level, there is no record, and by identifying the number of times the output Vx reaches a high level and the period during which the output Vx is at a high level, it is possible to determine whether it is an EP record or an LP record and obtain a discrimination output.

In the above embodiment, a record response assembly consisting of a sensor pin holder H in which a pair of sensor pins P ₁ and P ₂ are displaceably incorporated is mounted on a turntable T, while a light receiving diode D and a phototransistor PT are mounted on a cabinet C. This can be achieved by installing an optical detection assembly consisting of a holder _H1 with a By rotating the sensor pin holder H on the same plane as the turntable T, in the case of an LP record, it is possible to adjust the period during which the output _V3 is at a high level, such as _T2 , or the interval at which the output V3 is at a high level.

According to the record detecting device for a player of the present invention, as described above, since a plurality of record detecting pieces that are displaced in response to a record are provided on the same optical detecting means, the number of optical detecting means can be reduced.
As a result, there are great practical advantages such as the possibility of simplifying the configuration.

[Brief explanation of the drawing]

1A and B show a plan view and a sectional view of a record detecting device for a player before improvement according to the present invention, and FIGS. 2 A and B show a plan view and a sectional view of an embodiment of the record detecting device for a player according to the present invention. 2C and D show a partially enlarged plan view and a sectional view of the same as above, FIG. 3 shows a partially enlarged plan view of another embodiment of the same, and FIGS. B shows an explanatory diagram for explaining the operation of the above, FIG. 5 shows an electric circuit diagram of the same, and FIGS. 6A and B show output waveform diagrams of the same. T: turntable, P ₁ and P ₂ : sensor pin,
S ₁ and S ₂ : Return spring, C: Cabinet, D:
Light emitting diode, PT: Phototransistor, EP:
EP record, LP: LP record.

Claims (1)

[Scope of Claims] 1. The turntable is provided with a record detection piece that is displaced in response to records placed thereon, and an optical detection means is fixed below the turntable to control the opening and closing of the optical path by this detection piece. In the case where a plurality of record detection pieces are arranged on a turntable and are shifted in the radial and circumferential directions, one optical detection means can be used to open and close the optical path with a plurality of record detection pieces. A record detection device for a player, characterized in that it is provided to be controlled.