JPH0244358Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> This invention relates to an improvement of a head position control mechanism for a tape recorder that controls the head position by using the rotational force of a motor.

<Prior art and its drawbacks> Examples of general mechanisms that use the rotational force of a motor to control the position of the head include PLAY, FF,
There is one in which a motor switch is turned on and off by a switch lever linked to each operation button such as REW, and the motor is driven when the switch is turned on. To control the head position as the motor rotates, the cam is rotated when the motor is turned on, and the cam driven lever pushes the head forward until the cam radius is at its maximum, and when the STOP button is operated, the motor is rotated again. The cam radius is decreased from the maximum to the minimum, and the return force of the return spring at that time returns the head to its original position. In this way, when the PLAY button is operated, the cam is rotated to push the head forward, and when the STOP button is pressed, the cam is rotated further to reduce the cam radius from the maximum to the minimum. However, with this type of mechanism, if you press the STOP button immediately after pressing the PLAY button, the cam will rotate a little and then stop, so the head will return to its original position. It ends up stopping at a position where it has moved forward by a length corresponding to the amount of rotation. That is, if the STOP button is pressed immediately after pressing the PLAY button, the head moves forward a little and remains there, causing the inconvenience that the cassette tape cannot be removed from the tape recorder.

Therefore, in the past, a separate switch was provided to detect when the cam was rotating a little, that is, when the head was between the original position and the play operation position, and when this switch was on, the switch was turned on.
The motor rotates even when the button is pressed, so that the cam position, that is, the head position, does not stop halfway. FIG. 1 shows a stop state diagram of a conventional head position control mechanism. In the figure, 1 is the REW button, 2 is the PLAY button, and 3 is the REW button.
This is the FF button, and 4 is a switch lever that turns on the motor switch 6 when moved to the right against the spring 5. The switch lever 4 is formed with inclined parts 40 to 42, and pins 1a, 2a, 2a, which are provided on these inclined parts project from the levers of the respective buttons.
3a are in contact with each other. In the stopped state shown in the figure, the cam 7 engages with a driven pin 8a protruding from a cam driven lever 8, and the tip of the cam driven lever 8 is in contact with the rear edge of the head stand 9. In addition, the notch part of the cam 10 coaxially connected to the cam 7 has an L
One end of the letter-shaped lever 11 is located, and the contact of the motor control switch 12 is located at the other end. With the above configuration, when the PLAY button 2 is pressed in the stopped state shown in the figure, the switch lever 4 moves to the right and the switch 6 is turned on. The motor now begins to rotate, causing the cam 7 to rotate clockwise. Also cam 1
0 also rotates, the lever 11 rotates counterclockwise, turning the switch 12 on. Immediately after pressing PLAY button 2, press the STOP button (not shown)
When pressed, the PLAY button 2 returns to its original position, the switch lever 4 is moved to the left by the return spring 5, and the switch 6 is turned off. The state at this time is shown in FIG. When the switch 6 is turned off, the motor-on signal through the switch 6 is canceled, but as shown in FIG.
0, the motor drive signal continues to be supplied to turn on the switch 12;
From the state shown in FIG. 2, the cams 7 and 10 further rotate clockwise in the same way as when the STOP button is not pressed. The cam rotates approximately once, and the driven pin 8a
The switch 12 is turned off when the cam diameter at the position where it contacts reaches its maximum. And at this time STOP
Since the button has already been pressed, the cam is further rotated slightly clockwise by a mechanism not shown, and when the cam diameter changes from the maximum to the minimum, it returns to its original stop state.

As mentioned above, the conventional head position control mechanism has two
The two switches 6, 12 are turned on and off by the interaction of the cams 7, 10 and the three levers 4, 8, 11, respectively, to prevent the head from being in a halfway position. However, in this structure, the number of cams, levers, and switches used increases, resulting in an increase in cost.

<Purpose of the invention> The purpose of the invention is to provide a head position control mechanism for a tape recorder that requires only one switch and fewer cams and levers.

<Structure of the invention> This invention is based on the fact that the cam driven lever is brought into contact with the switch lever, and the contact portion is shaped so that the displacement of the cam driven lever turns on the motor switch via the switch lever. The feature is that even when the cam slightly displaces from the stop position and attempts to stop, the cam driven lever displaces the switch lever, thereby turning the motor switch on even if the PLAY button is pulled. This is how it was done.

<Embodiment> FIG. 3 shows a stop state of a head position control mechanism according to an embodiment of the invention, and FIG. 4 shows its play state. FIG. 5 is a diagram showing the state when the cam has rotated a little.

In the drawings, parts that are the same as or equivalent to those of the conventional mechanism shown in FIGS. 1 and 2 are designated by the same reference numerals.

In terms of configuration, the head position control mechanism of this embodiment differs from the conventional mechanism shown in FIG. The right end portion of the switch lever 4 is brought into contact with the right end portion of the switch lever 4, and the shape of the contact portion is adjusted to match the slope portion 4 formed on the switch lever 4.
3 is shaped so that the pin 8b protruding from the cam driven lever 8 comes into contact with it. With this configuration, when the PLAY button 2 is pressed in the stop state shown in FIG. move in the direction. Therefore, the switch 6 is turned on, the motor is driven, and the cam 7 begins to rotate clockwise. As the cam 7 rotates, the cam driven lever 8 begins to rotate counterclockwise around the pin 8c, pushing the head stand 9 forward.
When the cam 7 makes approximately one rotation and the cam diameter at the contact position of the driven pin 8a reaches its maximum, the rotation transmission mechanism from the motor to the cam 7 is released by a mechanism (not shown). For this reason, the head stand 9 stops at a position where it has moved forward by the maximum length, as shown in FIG. 4, and maintains that position. When the STOP button (not shown) is pressed in this play state, the PLAY button 2 returns to its original position, and the switch lever 4 moves to the left by the return force of the spring 5 and returns to its original position.
At the same time, the cam 7 is operated by a mechanism (not shown) (such as a lateral pressure spring that is linked to the STOP button and applies rotational force to the cam only when the STOP button is pressed).
The rotational force is transmitted to the cam 7, and the cam 7 rotates a little. As a result, the cam diameter at the contact position between the driven pin 8a and the cam 7 changes from the maximum to the minimum, and the cam driven lever 8 rotates clockwise around the pin 8c by the action of the return spring 13 and returns to its original position. Return. Further, the head stand 9 is also returned to its original position, which is the most retracted position of the head, by the action of the return spring 14. In this way, when the play state is maintained for a certain period of time by pressing the PLAY button 2, and then the play state is canceled by pressing the STOP button, the operation is similar to that of the conventional mechanism.

On the other hand, if the PLAY button 2 is pressed and the STOP button is pressed before the cam 7 completes one rotation, the cam driven lever 8 rotates slightly counterclockwise around the pin 8c, causing the switch lever 4 and the cam driven lever to rotate slightly. 8, the pin 8b touches the inclined portion 4.
3 and move the switch lever 4 to the right. Therefore, even if the STOP button is pressed and the PLAY button 2 is released, the switch 6 remains on as shown in FIG. 5, and the cam 7 continues to rotate counterclockwise. As long as the cam 7 rotates counterclockwise, the pin 8b pushes up the inclined portion 43, so the switch 6 remains on, until the cam diameter reaches its maximum at the position where the driven pin 8a abuts. That is, the cam 7 continues to rotate until it reaches the state shown in FIG. When the state shown in Fig. 4 is reached, the STOP button has already been pressed and the PLAY button has been released, so the cam 7 rotates a little further, and the cam diameter at the position where the driven pin 8a comes into contact is at its minimum. becomes. As a result,
Even if the PLAY button 2 is pressed and the STOP button is pressed immediately, the head stand 9 will reciprocate once and return to the original stop state shown in FIG. 3. In addition, in this embodiment, when the time from when the PLAY button is operated to when the STOP button is operated is extremely short, the driven lever 8
The amount of displacement of the head stand 9 is small and it becomes impossible to turn on the switch 6.
In order to prevent the cam from moving forward, a slight distance t is formed between the rear edge of the head stand 9 and the side edge of the cam follower lever 8 in the stopped state shown in FIG. I have to. Therefore, when the amount of displacement of the cam driven lever 8 is extremely small, the cam 7 does not rotate once as in the above operation, and the switch lever 4 and the cam driven lever 8
is slightly displaced and then stops.

<Effects of the invention> As described above, according to this invention, the cam driven lever is brought into contact with the switch lever, and the shape of the contact portion is such that the displacement of the cam driven lever turns on the motor switch via the switch lever. Since the structure is only shaped to correspond to the direction, the structure is very simple and has the advantage of requiring only one motor switch and one cam for controlling the head position.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams respectively showing a stop state of a conventional head position control mechanism and a diagram showing a state when the STOP button is operated immediately after the play button is operated. Furthermore, Fig. 3 shows the stop state of the head position control mechanism which is an embodiment of this invention, Fig. 4 shows the play state, and Fig. 5 shows the state when the STOP button is operated immediately after the play button is operated. FIG. 2...PLAY button, 4...Switch lever,
6...Motor switch, 7...Cam, 8...Cam driven lever, 9...Head stand.

Claims (1)

[Claims for Utility Model Registration] Operated by a switch lever that turns the motor switch on and off in conjunction with the play button and a cam that rotates when the motor is turned on, and pushes the head stand forward as the cam rotates. a cam driven lever; when the play button is operated, the motor switch is turned on to rotate the cam, and the cam driven lever pushes the head base to a predetermined position. In the position control mechanism, the cam driven lever is brought into contact with the switch lever, and the contact portion is shaped such that displacement of the cam driven lever turns on the motor switch via the switch lever. A tape recorder head position control mechanism characterized by: