JPS59193565A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the automatic stoppage and to improve the safety for a magnetic recording/reproducing device by actuating a pulse generating circuit with the output of a tape end detecting circuit and detecting by another detecting circuit the fact that the pulse intervals of said pulse generating circuit are reduced. CONSTITUTION:When a tape reaches its end and the revolution of a reel drive disk is stopped, the output of a tape end detecting circuit 3 is set at level 0 after T seconds. Then transistors TR5 and 6 conduct through a switch 4, and an automatic inverting solenoid 7 is actuted to switch the direction where the tape is traveling at a constant speed. When this inverting action is repeated some times, the reel drive disk has no revolution at all. The circuit 3 produces a pulse of level 0 after T seconds from the time point when the reel drive disk has no revolution. The O-level pulse turns on and off a TR11 repetitively. Then a capacitor 12 is charged via a resistance 14 and dischrged via resistances 15 and 16 respectively. Thus the both-end voltage of the capacitor 12 is gradually raised up. When a TR13 is turned on, its collector is set at level 0. Then a TR10 is turned off to stop automatically the opeation of a magnetic recording/reproducing device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reciprocating type magnetic recording and reproducing apparatus capable of running a magnetic tape at a constant speed in both the forward and reverse directions.

Conventional configuration and its problems Conventional reciprocating magnetic recording and reproducing devices cannot reproduce data.

When the end of the tape is detected while the tape is running at a constant speed during recording, an automatic reversing mechanism is activated to switch the tape feeding direction. However, especially when playing back or recording using a cassette tape, if the magnetic tape wraps around a capstan etc. and the tape is forced to stop running, an automatic reversal operation is performed and the end of the tape is reached. There is a drawback that the reversing operation described above is repeated until a person notices and performs a stop operation. In addition, in the case described in item 2, the tape running drive motor may stop rotating; in this case, the automatic reversing nozzle and the motor described above may generate heat, which could lead to a dangerous situation that could lead to a fire. Ta.

OBJECT OF THE INVENTION The present invention solves the drawbacks of the prior art.When the tape wraps around the capstan or the motor is locked, an automatic stop means is activated to stop the tape feeding, thereby increasing the safety of the device. The purpose is to increase the

Structure of the Invention The present invention includes an end detection circuit for detecting the end of a magnetic tape;
automatic reversing means that automatically switches the constant speed running direction of the tape according to the detection output of the end detection circuit; a pulse generation circuit that receives the output of the end detection circuit and generates pulses; and a pulse generation interval of the pulse generation circuit. It is equipped with a detection circuit that detects that the length becomes short, and an automatic stop means that automatically stops the device based on the detection output of this detection circuit. The magnetic tape is constructed in such a way that if the magnetic tape runs out, the running direction of the magnetic tape is not reversed and the running is immediately stopped, thereby preventing dangerous situations such as the motor overheating.

DESCRIPTION OF THE EMBODIMENT FIG. 1 shows an embodiment of the present invention, and 1 indicates a reel stand (
A ring-shaped magnet 2 rotates in conjunction with the rotation of the magnet 1 (not shown), and is a Hall IC that detects the change in magnetic pole due to the rotation of the magnet 1 and outputs the output shown in FIG. 2 (7'). Reference numeral 3 designates a tape end detection circuit that receives the output from the Hall IC 2, and this detection circuit 3 generates a pulse at the P0'' level T seconds after the pulse from the Hall IC 2 disappears, and thereafter the Hall IC continues to generate pulses. If there is no pulse from IC2, the configuration is such that the same pulse of °'0'' level is generated every T seconds. FIG. 2(a) shows the output waveform of the detection circuit 3. Reference numeral 4 denotes a changeover switch which is switched in conjunction with the tape running operation, and when the tape is running at a constant speed during playback and recording, the movable contact 4a and one fixed contact 4b are connected.
When the tape runs at high speed with one fast forward and one rewind, the movable contact 4a and the other fixed contact 4C are connected.

5.6 is a transistor that controls the operation of the automatic reversal solenoid 7; when the automatic reversal solenoid 7 is operated, a constant speed tape running direction switching mechanism (not shown) is activated to change the constant speed running direction of the magnetic tape. is now inverted. 8 is the play button.

A locking solenoid locks a tape running operation button (not shown) such as a fast forward button in an operating position; 9 is a power switch that is closed by operating the tape running operation button; 9 is turned on υ, the transistor 1o becomes conductive, which activates the locking solenoid 8 and locks the operated operation button in the operating position, and the transistor 10 becomes non-conductive, so that the locking solenoid 8 is activated. 8 is in a non-operating state, the operation button that was locked in the operating position returns to the original non-operating position, and the power switch 9 is turned off.

Reference numeral 11 denotes a switching transistor that turns on and off in response to the output pulse of the termination detection circuit 3, 12 a capacitor that charges and discharges depending on the on and off operations of the transistor 11, and 13 a voltage across the capacitor 12 at a predetermined level. This transistor is turned on when the value exceeds E, and the collector of this transistor 13 is connected to the base of the transistor 1o that controls the locking solenoid 9.

The operation of the above embodiment will now be explained.

Assuming that the magnetic tape is being played back, a pulse as shown in Figure 2 is generated at the output end of the Hall IC2.When the tape reaches its end, the rotation of the reel stand is stopped. Then (at time ts), the output of the termination detection circuit 3 becomes "o" level after T, and this "o" level output conducts the transistors 5 and 6 through the switch 4, and the automatic reversal solenoid γ is activated to turn the tape off. The constant speed running direction of the vehicle is switched.

On the other hand, when the tape reaches the end in the fast forward 91 rewind state, as mentioned above, the output of the end detection circuit 3 becomes "°O" level after T from the time 1 s when the rotation of the reel stand is stopped. 4, the transistor 10 is made non-conductive, the operating button is returned to its original position, and the device is automatically stopped.

In addition, if the rotation of the JIJ-ru table is stopped due to the tape being wound around the capstan during the above-mentioned playback, the automatic reversing nozzle is activated and the constant speed running direction of the tape is switched as described above. If the reversing operation is repeated several times, the reel stand will no longer rotate at all. From this point on, the termination detection circuit 3 generates a "0" level pulse every T seconds as shown in FIG. However, discharge occurs through resistors 15 and 16, and capacitor 1
The voltage across point 2 gradually increases toward point E, as shown in FIG. The voltage across this capacitor 12 reaches a level E that turns on the transistor 139, and when the transistor 13 turns on, its collector becomes the "0" level as shown in Figure 2), turning off the transistor 1o. , the locking solenoid 8 returns to the non-operating state and the device automatically enters the stopped state.

Note that in normal operating conditions, the output pulses of the termination detection circuit 3 are at long intervals of at least every few minutes, so in this case, the charge in the capacitor 12 is completely discharged;
The voltage across it will never reach E.

Effects of the Invention According to the magnetic recording/reproducing apparatus of the present invention, a pulse generation circuit is activated by the output from the tape end detection circuit, and a separate detection circuit detects that the pulse interval from this pulse generation circuit becomes short. Since the device is configured to automatically stop, even if tape wrapping occurs while the tape is running at a constant speed, the device will always be stopped and dangerous situations such as fire can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 1...Magnet, 2...Hall IC, 3...
...Tape end detection circuit, γ...Automatic reversal solenoid, 8...Lock solenoid, 11...
... Switching transistor, 12 ... Capacitor, 13 ... Automatic stop transistor.

Claims (1)

[Claims] an end detection circuit that detects the end of the magnetic tape; an automatic reversing means that automatically switches the constant speed running direction of the tape according to the detection output of the end detection circuit; and a pulse that receives the output of the end detection circuit and generates a pulse. A magnetic recording/reproducing device comprising a generation circuit, a detection circuit for detecting that the pulse generation interval of this pulse generation circuit becomes short, and an automatic stop means for automatically stopping a device based on the detection output of this detection circuit. Device·