JPS581875Y2 - cassette tape recorder - Google Patents

Description

[Detailed description of the invention] This invention returns the drive mechanism to a stopped state by detecting that power is supplied during playback, fast forwarding, and rewinding operations, and that the rotation of the reel shaft has stopped due to the end of tape winding. The present invention relates to a cassette tape recorder having an automatic stop device.

A high-grade cassette-type tape recorder called a tape deck is equipped with a so-called automatic stop device that returns the drive mechanism to a stopped state by utilizing the characteristic of cassette-type tape recorders that the rotation of the reel shaft stops at the end of tape winding. We are prepared.

The rotation detection mechanism that constitutes such an automatic stop device includes a method of detecting the rotation of the take-up reel shaft and a method of detecting the rotation of the rewind reel shaft, but in general, the method is advantageous for tape running characteristics such as wow and black. A method for detecting the rotation of the take-up reel shaft has been used and will be described below.

If you press the button on a cassette tape recorder configured in this way and perform a rewind operation without a cassette installed, the drive mechanism of the tape recorder will enter the rewind state, but the take-up reel shaft will stop automatically, so it will stop automatically. The device is activated and the drive mechanism is returned to its stopped state.

However, when playback or fast-forwarding is performed, the take-up reel shaft rotates, so the automatic stop device does not operate, and the tape recorder's drive mechanism continues to drive even though no cassette is installed. become.

Such operation not only causes wear of drive parts such as belts and pinch rollers, but also wastes valuable power in portable tape recorders that use batteries.

The present invention has been developed in view of these points, and will be described in detail below with reference to the illustrated embodiments.

In the figure, 1 is a signal generation circuit that generates an alternating current signal as the reel shaft rotates, 2 is a switching transistor that repeatedly turns on and off according to the signal from the signal generation circuit 1, and 3 is a signal generation circuit that the switching transistor 2 is connected to. It is a charging/discharging capacitor that is charged through the resistors 4 and 5 when the transistor 2 is in the off state, and discharged through the resistors 5 and 6 and the collector-emitter path of the transistor 2 when the transistor 2 is in the on state. During rotation, the charging potential is set so as not to rise to a predetermined value.

7 is a transistor that is turned on when the charging potential of the charging/discharging capacitor 3 exceeds a predetermined value; 8 is a transistor that is turned on as the transistor 7 is turned on, and a stopping plunger 9 is turned on; This is a transistor that turns on the drive transistor 10 that causes the suction operation.

11 is a switch that is closed during playback, fast forwarding, and rewinding operations to supply power to the aforementioned circuit; 12 is a detection switch that is opened when a cassette is inserted; It is connected between the power supply line 14 and the charging/discharging capacitor 3 together with a resistor 13 to charge the capacitor.

15 is a feedback circuit provided for rapidly inverting the transistors 7, 8 and 10.

The present invention is constructed and operated as described above, and its operation will now be explained.

First, the operation when a cassette is installed will be explained.

When the cassette is installed, the detection switch 12 is opened, and when playback, fast forwarding, or rewinding operations are performed in this state, the switch 11 is closed and the drive mechanism enters the operating state corresponding to each operation.

While the tape is running in each operating state, an AC signal is output from the signal generation circuit 1 as the reel shaft rotates, and the switching transistor 2 repeats on/off operations, so the charging potential of the charging/discharging capacitor 3 exceeds a predetermined value. It will never rise.

Therefore, the transistors 7, 8 and 10 are not turned on, and the stop plunger 9 does not perform the suction operation.

When the tape is driven and reaches the end, the rotation of the reel shaft is stopped and the alternating current signal from the signal generating circuit 1 disappears.

As a result, the switching transistor 2, which has been repeatedly on and off, is continuously turned off, and the charging/discharging capacitor 3 is no longer discharged.

The charging potential of the light emitting discharge capacitor 30 increases, and when the charging potential reaches a predetermined value, the transistor 7.8.1
0 is reversed to the on state, causing the stopping plunger 9 to perform a suction operation.

As a result, the drive mechanism of the tape recorder is released and the tape recorder comes to a halt.

Although the automatic stop device operates as described above, the operation when no cassette is installed will be described next.

When the cassette is not installed, the detection switch 12 is in a closed state as shown.

In such a state, when a playback, fast forwarding or rewinding operation is performed, the switch 11 is closed and the drive mechanism is put into operation.

However, since the detection switch 12 is in a closed state, the charging/discharging capacitor 3 is charged at a predetermined time constant through the detection switch 12 and the resistor 13 at the same time as the switch 11 is closed.

When the charging potential of the charge/discharge capacitor 3 reaches a predetermined value after a predetermined period of time, the transistor γ 810 is turned on and the stop plunger 9 is operated to attract.

As a result, the tape recorder is returned to its stopped state and the unnecessary operation of the drive mechanism is released.

As explained above, according to the present invention, even if a drive operation is performed without a cassette installed, the drive operation can be canceled, thereby reducing unnecessary wear and tear on the parts that make up the drive mechanism. Waste can be prevented.

As the mechanism of the housing uses a charging/discharging capacitor that constitutes an automatic stop device, the circuit is simple, and furthermore, since the release operation is performed after a predetermined period of time, it is possible for the user to press the button while the user presses the button. There is no release action and it does not give a mysterious impression to the user0.

[Brief explanation of drawings]

The illustrated circuit is one embodiment of the present invention. Explanation of main drawing numbers, 1...Signal generation circuit, 2...
...Switching transistor, 3...
Charge/discharge capacitor, 9... Stop plunger 12... Detection switch.

Claims (1)

[Scope of utility model registration request] A cassette-type tape recorder that is supplied with power during playback, fast-forwarding, and rewinding operations, and has an automatic stop device that returns the drive mechanism to a stopped state by detecting the stoppage of rotation of the reel shaft upon completion of tape winding. In,
A signal generation circuit that outputs an alternating current signal as the reel shaft rotates, a switching transistor that repeatedly turns on and off according to the output signal of the signal generation circuit, and a charging and discharging capacitor that repeatedly charges and discharges as the switching transistor turns on and off. , a transistor that turns on when the charging potential of the charge/discharge capacitor reaches a predetermined value and causes the stop plunger to operate as a suction, and a detection switch that detects whether or not a cassette is attached. The charging/discharging capacitor is charged by a predetermined time constant through the detection switch when the drive operation is turned off, and the drive operation is canceled after a predetermined time by suction of the stop plunger. A cassette tape recorder.