JPS5814345A - Magnetic sound recording and reprducing device - Google Patents

Abstract

PURPOSE:To prevent the breakdown of a device and a tape, by detecting the reversal of a reel base for abnormality to reverse or stop the tape running in a tape driving part. CONSTITUTION:A disc 1 rotated synchrnously with a reel base is provided with plural holes so as to obtain prescribed pulses. When a magnetic tape is run, a pulse signal is outputted to the output terminal of a photo detecting part 3 in accordance with the normal rotation direction or the reverse rotation direction. Intervals of high pulses of this pulse signal are counted with a period shorter than the minimum period by a counting circuit of a controlling part 5, and three counted numbers older than the current counted number are stored in a storage circuit of the controlling part 5 to grasp the state of counted numbers. When a microcomputer of the controlling part 5 detects reversal, a tape driving operation is stopped to protect the driving mechanism and the tape from breakdown.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording/reproducing machine, and more particularly to a malfunction prevention mechanism thereof, which prevents the magnetic tape from being damaged when it is wound around a tape drive mechanism.

Various methods have been devised to prevent the magnetic tape from being caught in the tape drive mechanism, but none of them have been perfect. In the present invention, by detecting the rotational direction of the reel stand while the tape is running, when an abnormality occurs in the tape running due to winding of the magnetic tape, etc., it is detected that the reel stand is reversed and the tape drive mechanism is stopped. In addition, magnetic recording/playback machines equipped with an automatic reversing mechanism are designed to reverse the tape running direction of the tape drive mechanism.
This is to prevent damage to the equipment or the tape itself due to abnormal tape running.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of the main parts of the device for detecting the rotational direction of the reel stand of the magnetic recording/reproducing machine of this embodiment. Reference numeral 1 denotes a disc that rotates in synchronization with the reel stand, and 2゜a denotes a light emitting part and a light receiving part, respectively, and these light emitting part 2 and light receiving part 3 are controlled by a control part 6.
connected to. This control section 6 is a tape running drive mechanism section 4.
It also controls the motor, solenoid (not shown), etc., and is composed of a microcomputer. Furthermore, audio processing 3.

It also controls muting and the like of the section 6. Although not shown, the audio processing section 6 is also connected to a magnetic head included in the tape drive mechanism section 4, and performs audio recording and reproduction processing. FIG. 2 is a detailed view of the disc 1, in which holes 11L to 1f are made. The intervals between these holes are set so that a predetermined pulse output, which will be described later, can be obtained.

With the above configuration, when the magnetic tape is running, the light receiving section 3
At the output end of the running direction (
In this case, it is output as normal rotation ′). Further, in the reverse direction, a pulse output shown in FIG. 4 is generated. Here's the third. The interval between the bipulses shown in FIG. 4 is cycled by the count circuit of the control unit 60 at a cycle smaller than the minimum cycle of the bipulse, and three of the counts older than the current one are stored in the memory circuit of the control unit 6. Understand the status of those three counts. Assuming that the above three pulses are a, b, and c in descending order, Fig. 6 (
4) Three types of states as shown in (01, (c)) occur, and when the inversion occurs, three types of states as shown in Figure 6 (a1, (@, (c)) occur. .Accordingly, in this embodiment, the control unit 6 is used to determine which of the three detected counts corresponds to FIG.
A microcomputer is used to perform the processing according to the flowchart shown in FIG.

For example, if the symbol shown in FIG.
) Since the determination of b is No, the next determination is b>C. Here, the answer is YES, and then a>c is determined.

This is also YES, indicating that normal rotation has been determined. In this flowchart, in order to detect that the tape running is reversed, a memory address is set. Therefore, if the current normal rotation operation continues, K=1, but
When a reversal is detected at a certain moment, the judgment 1c=o is made, and the result is No in this case, and the running operation of the tape drive mechanism is stopped to protect the mechanism from being seriously damaged due to malfunction. Furthermore, if the tape drive mechanism has an automatic tape running direction reversal mechanism, the tape running direction may be reversed without stopping the tape drive mechanism.

As explained above, according to the magnetic recording/playback device of the present invention,
In addition to preventing increased damage due to equipment malfunction, it is also possible to prevent malfunctions at the same time as controlling the tape drive mechanism using a microcomputer, so the number of parts does not increase and the effect is large. It is what it is.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the main parts of a magnetic recording/reproducing machine according to an embodiment of the present invention, Fig. 2 is a plan view of a disc 1, Figs.
The figure shows the magnetic tape running in the normal direction. Waveform diagrams of output pulses from the light receiving unit 3 during reversal, Fig. 6 9) to (c), Fig. 6 9) to (c) are pulse intervals when the running direction of the magnetic tape is normal/9 reverse. FIG. 7 is a diagram for explaining the operation of the control circuit. 1... Disc, 2... Light emitting section, 3...・・・
. . . Light receiving section, 4 . . . Tape drive mechanism section, 6.
...Control unit, 6...Audio processing unit, 11L
~1f...hole. 6. Name of agent: Patent attorney Toshio Nakao and 1 other person91
Figure 1 fC Figure 3 Figure 4 Figure 5 (wa (hair)
c) Figure 6

Claims (1)

[Claims] A reel base rotation detection mechanism that outputs pulses with at least three different cycles in synchronization with the rotation of a reel base of a tape drive unit that drives a magnetic tape, a count circuit that determines the cycle of the pulses, and a count circuit that outputs pulses with at least three different cycles; A tape running direction determining circuit is provided which detects the output order by the count number of a counting circuit and determines whether the tape running direction of the drive section is forward or reverse, and this tape running direction determining circuit detects that the tape running is reversed. A magnetic recording/reproducing machine configured to reverse or stop the tape running of the tape drive unit by being turned on.