JPS6156568B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reel stand braking device used in a cassette type tape recorder, and an object of the present invention is to provide an excellent reel stand braking device that can effectively brake with a simple configuration. That is.

Generally, in a cassette type tape recorder,
When applying a brake to the reel stand, use another brake plate 3 so that both ends thereof face the reel stand 1 on the take-up side and the reel stand 2 on the supply side, as shown in Fig. 1. By bringing the reels into a stopped state or a temporarily stopped state, the brake plates 3 come into pressure contact with the outer peripheries of the reel stands 1 and 2, respectively, and apply a brake to the reel stands 1 and 2. However, in this type of reel, the braking force acting on each reel stand 1, 2 on the take-up side and the supply side is not necessarily uniform, and when the braking force on the reel stand 2 on the supply side is small, it stops abruptly than in a queue state. When the capstan is turned on or paused, the magnetic tape wraps around the capstan. That is, in the queue state, the magnetic tape is running at high speed while contacting the magnetic head or head pad, and the magnetic tape may be charged with a large amount of static electricity.
The capstan is still rotating at that moment, so there is a problem in that the magnetic tape is attracted by the static electricity and may wind around the capstan.

The present invention eliminates the above-mentioned conventional drawbacks and provides an excellent reel stand brake device that can prevent this type of winding with a simple structure.

EMBODIMENT OF THE INVENTION Hereinafter, the reel stand brake device of this invention is demonstrated with the drawing of one Example. In FIG. 2, 4 is a take-up reel stand, 5 is a supply reel stand, 6 is a rotating shaft of the motor, 7 is a rotating lever whose one end is pivoted by a shaft 8, and 9 is the center of the rotating lever 7. A transmission roller 10 is pivotally attached to the shaft 8 and transmits the rotation of the rotating shaft 6 to the reel stands 5, 4 on the supply side or the winding side. This is a spring that applies a biasing force in a direction in which the transmission roller 9 is pressed against the transmission roller 9 . Here, the rotation lever 7 includes a transmission roller 9, and constitutes a rolling contact mechanism that presses the transmission roller 9 into contact with the reel stands 5, 4 on the supply side or the winding side depending on the rotation direction of the rotation shaft 6 of the motor. ing.

FIG. 3 is an electrical connection diagram for driving the motor, and in the figure, M is the motor, S ₁ to S ₃ , S ₄
~ _S6 , _S7 ~ _S9 , _S10 ~ _S12 , _S13 ~ _S15 are switches and TRs that are turned on when the stop button, pause button, play button, fast forward button, and rewind button are operated, respectively. is a transistor that controls the current flowing to the motor M,
R ₀ , R ₁ , R ₂ , and R ₃ are the above transistors TR
The base bias resistor C is a capacitor that forms a time constant circuit with the resistor _R1 .

In the above embodiment, if the play button is operated now, switches S ₇ to _{S 9} are turned on, so a predetermined bias is applied to the base of the transistor TR via switch S ₇ and resistors R ₂ and R ₀ . Therefore, the transistor TR is turned on in a region corresponding to this bias value. Therefore, current will flow through the motor M in the direction of arrow A through the transistor TR and switches _S9 and _S8 , and the rotating shaft 6 of the motor M will rotate in the direction of arrow C in Figure 2. . Therefore, the transmission roller 9 rotates in the direction of arrow D, and the rotation lever 7 rotates in the direction of arrow E. Therefore, in this state, the transmission roller 9 comes into pressure contact with the take-up reel stand 4 and rotates the take-up reel stand 4 in the direction of arrow F.

On the other hand, if you operate the fast forward button, the switch
Since S ₁₀ to S ₁₂ are on, the switch is not activated in this case.
A predetermined bias is applied to the base of the transistor TR via S ₁₀ and resistors R ₃ and R ₈ , so that the transistor TR is turned on in a region different from that in the case of reproduction. In other words, if the value of resistor _R3 is set smaller than the value of resistor _R2 , the base of transistor TR will be biased at a higher voltage than in the case of regeneration, and a higher voltage will be applied to motor M. As a result, the rotational speed of the motor M becomes faster. In this case, the rotational direction of the motor M is the same as that for reproduction, and the take-up reel stand 4 rotates in the direction of arrow F via the transmission roller 9.

Next, if you operate the rewind button, Switch S ₁₃
~ Since _S15 is turned on, a predetermined bias is applied to the base of the transistor TR via the switch _S13 , resistors _R3 and _R8 , and the transistor TR is turned on in the same state as in the case of fast forwarding. Become.

In this case, a current flows to the motor M in the direction of arrow B via the transistor TR and the switches S ₁₅ and S ₁₄ , so that the motor M rotates in the opposite direction to that in the case of playback and fast forwarding. Therefore, in this case, the rotating shaft 6 of the motor M, the transmission roller 9,
The respective rotation directions of the rotation lever 7 are all opposite to the arrows C, D, and E, and the transmission roller 9
is pressed against the supply reel stand 5 and rotates the supply reel stand 5 in the direction of arrow G.

When the stop button or the pause button is finally operated, the switches S ₁ to S ₃ or S ₄ to _{S 6} are turned on, so the base of the transistor TR is connected to the switch S ₁ or S ₄ and the resistor R. ₁ , a capacitor C, and a resistor _R0 . Therefore, in this case, the transistor TR will be turned on for a certain period of time determined by the resistor R ₁ and the capacitor C, and thereafter the transistor TR will be turned off. and,
During a certain period when the transistor TR is on, current flows to the motor M in the direction of arrow B via the transistor TR and the switches S ₃ , S ₆ or S ₂ , S ₅ , so that the transmission roller 9 is turned on as in the case of rewinding. will drive the supply reel stand 5 to rotate in the direction of arrow G. In this case, since the value of resistor R ₁ is set sufficiently larger than the values of resistors R ₂ and R ₃ , the current flowing through motor M can be made considerably smaller than in the case of playback, fast forwarding, and rewinding, and it is possible to prevent the supply reel stand 5 itself from rotating in the direction of arrow G by simply applying a braking force in the direction of arrow G to the supply reel stand 5. .

In this way, according to the above embodiment, when the stop button or pause button is operated, the transmission roller 9 is reversely switched but the supply reel stand 5 is not rotated, and the motor M is rotated in the opposite direction as in the case of regeneration or fast forwarding. Since a braking force is applied when the tape tries to rotate in this direction, the magnetic tape will never wrap around the capstan even if the magnetic tape is abruptly changed from a playback state or fast forward state to a stop state or a pause state. In other words, since the capstan generally rotates in the direction in which the magnetic tape is fed during playback or fast forwarding, if the motor rotates in the opposite direction when paused or stopped, the magnetic tape will be moved in the same direction as the capstan. It will be pulled in the opposite direction,
Therefore, the magnetic tape is never attracted to the capstan, and winding of the magnetic tape is completely prevented. Of course, in the case of queue operation, the running direction of the magnetic tape is the same as in the case of fast forwarding, so even if the queue state is abruptly changed to a stop state or a pause state, winding of the magnetic tape around the capstan is similarly prevented. be able to.

According to the above embodiment, when the rewinding state is switched to the stop state or the pause state, the motor is configured to rotate in the same direction as in the rewinding state. Wrapping can be completely prevented.

Although not specifically mentioned in the embodiment, if a switch is connected in parallel to the capacitor C and the switch is configured to turn on automatically when the play button, fast forward button, or rewind button is operated, these functions can be achieved. Since the charge stored in the capacitor C is completely discharged when the button is operated, there is an advantage that no malfunction will occur even when the stop button or pause button is subsequently operated.

As is clear from the above embodiments, the brake device of the present invention reverses and switches the transmission roller that is brought into contact with the supply reel stand and the take-up reel stand when the stop button or pause button is operated. The motor is configured to rotate in reverse within the range where the reel stand is not rotated, and apply a rotational biasing force to the supply reel stand so as to pull the magnetic tape in the opposite direction to the running direction of the capstan. It is extremely advantageous in practice, as it does not attract or become entangled at all.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional brake device, FIG. 2 is a schematic diagram of an embodiment of the reel stand brake device of the present invention, and FIG. 3 is an electrical connection diagram of a motor drive circuit constituting the device. . 4... Take-up reel, 5... Supply reel, 7...
Rotating lever, 8... shaft, 9... transmission roller, 10
...Spring, M...Motor, _S1 to _S15 ...Switch, TR...Transistor, _R0 to _R3 ...Resistance.

Claims (1)

[Claims] 1 A transmission roller to which a rotational force is applied by a rotational shaft of a motor is pivotally connected to a rotary lever whose one end is pivotally connected to the shaft, and the rotational direction of the transmission roller is changed depending on the rotational direction of the motor. , the rotary lever rotates in response to this, and the transmission roller is switched and press-contacted to the supply reel stand and the take-up reel stand, respectively, and when the rewind button is operated, the motor is activated. The motor drive circuit is provided with a motor drive circuit that rotates in the opposite direction to that in the playback state or fast-forward state, and the motor drive circuit switches the transmission roller in reverse when the stop button or pause button is operated from the playback state or fast-forward state. The polarity of the voltage supplied to the motor is reversed within a range where the supply reel base is not rotated even if the supply reel base is pressed against the supply reel base side, and the magnitude and time of the supply voltage is set, and the supply voltage is set. A reel stand brake device that includes an electric brake means that applies a braking force by canceling the moment of inertia of the reel.