JPH0142869Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a movable range limiting mechanism for a magnetic head in a magnetic drum type audio output device. This invention relates to a magnetic head movable range limiting mechanism designed to prevent damage to the magnetic head, its drive mechanism, the magnetic recording medium layer on the outer circumferential surface of the magnetic drum, etc. even if the magnetic head goes out of control due to a failure.

2. Description of the Related Art Audio output devices using magnetic drums are conventionally known and are used in various announcement systems. This device divides the magnetic recording medium layer on the outer circumferential surface of the magnetic drum into a large number of tracks, and a magnetic head that performs a track selection operation randomly accesses each track, and transmits audio information to a predetermined track via the magnetic head. It is configured for recording and playback.

In this case, it is necessary to make the magnetic drum as small and light as possible and to secure a certain recording capacity, so the magnetic head is pressed against the surface of the magnetic drum in order to improve the output level. At this time, the pressure must be as uniform as possible and a good contact state must be maintained at all times, and for this purpose, the elastic force of a leaf spring, coil spring, etc. is used. Therefore, the magnetic head continues to be in sliding contact with the magnetic recording medium layer on the outer peripheral surface of the magnetic drum even during the track selection operation (movement in the direction of the rotation axis of the magnetic drum).

The track selection operation of the magnetic head is performed by a sufficiently reliable control circuit and drive device.
There is a possibility that the magnetic head may malfunction due to some kind of failure and run out of control. If the magnetic head goes out of control, it may protrude from the magnetic recording medium layer on the outer peripheral surface of the magnetic drum, or even jump out from the edge of the magnetic drum, damaging the magnetic head, its drive mechanism, or the magnetic recording medium layer. There is a risk that recovery will be difficult.

The purpose of the present invention is to solve such technical problems and to be able to reliably stop the movement of the magnetic head at a predetermined position even if the magnetic head control mechanism goes out of control. There is no risk of damaging the head, its drive mechanism, or the magnetic recording medium layer, and it is mechanically extremely simple.
It is an object of the present invention to provide a highly reliable movable range limiting mechanism for a magnetic head that can be easily restored.

The present invention that can achieve this purpose is:
In summary, a pin is provided protruding from a magnetic head that is pressed against the outer circumferential surface of a magnetic drum by the elastic force of a spring, and the pin is arranged to follow a guide member, and the pin is attached to both ends of the guide member. This magnetic head movable range limiting mechanism has a stopper recess that can be inserted and locked.

Hereinafter, the present invention will be explained in more detail based on the drawings. FIG. 1 is an explanatory diagram showing one embodiment of a magnetic head movable range limiting mechanism according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a side view thereof. The magnetic head support member 1 is placed on a carriage member (not shown) that is movable in a direction parallel to the rotational axis of the magnetic drum 2 (indicated by arrow A) for track selection operation, and is supported by a shaft 3. It is rotatably supported. A leaf spring 20 is mounted on the front surface of the magnetic head support member 1.
is fixed, and a magnetic head storage case 5 containing a built-in magnetic head 4 is located at the tip thereof, and a coil spring 6 is attached to the end of the magnetic head support member 1. In other words, the magnetic head 4 is connected to the leaf spring 2.
0, and the coil spring 6
The magnetic head support member 1 receives a rotating force about the shaft 3 due to the tensile force in the direction of the arrow B, whereby the magnetic head 4 is always pressed against the outer peripheral surface of the magnetic drum 2 with a constant pressure. be.

Now, in the present invention, a pin 7 is provided protruding from the tip of the magnetic head storage case 5, and the tip of the pin 7 is arranged to follow the surface of the guide plate 8. In this embodiment, the guide plate 8 is vertically attached to the tip of a magnetic head lever 10 which is pivotable about an axis 9, and the guide plate 8 is attached to the magnetic drum at both ends thereof, as clearly shown in FIG. 2 magnetic recording medium layer 11
It has a structure in which a raised part 12 is formed at a position corresponding to the vicinity of the end of the pin 7, and a stopper recess 13 into which the tip of the pin 7 can be fitted and locked is formed in the raised part 12. and the magnetic head lever 10
Due to the action of the spring 14, the magnetic head 4
is set at such a position that it can be in pressure contact with the magnetic drum 2 at all times.

The operation of this device is as follows. Under normal conditions, as shown in Figures 2 and 3,
The magnetic head 4 is brought into pressure contact with the surface of the magnetic recording medium layer 11 of the magnetic drum 2 by the tensile force of the coil spring 6, selects a track, and records and reproduces audio information on a predetermined track. In the unlikely event that a trouble occurs in the control mechanism that performs the track selection operation of the magnetic head and the magnetic head 4 runs out of control beyond the area of the magnetic recording medium layer 11, the pins 7 will move along the surface of the guide plate 8. Therefore, the raised part 1
It will move up to 2. As a result, the magnetic head 4 separates from the outer surface of the magnetic drum 2, and if the runaway continues, the pin 7 will move into the stopper recess 13.
It is inserted into and locked. As a result, the runaway of the magnetic head 4 is completely stopped. Since the magnetic head 4 moves with the pin 7 tracing the surface of the guide plate 8, it is reliably fitted into the stopper recess 13 and the magnetic head does not move any further. In this way, even if the magnetic head control mechanism malfunctions due to some kind of failure and the magnetic head goes out of control, the magnetic head is first separated from the outer peripheral surface of the magnetic drum.
Since it is then locked and fixed, there is no risk of damage to the magnetic head, its drive mechanism, magnetic recording medium, etc.

If such a situation occurs, turn off the power to the device, inspect and repair the magnetic head control mechanism, and then remove the pin 7 from the stopper recess 13 and move it to an intermediate position on the guide plate 8. Just turn on the power.

In addition, in this embodiment, the magnetic head lever 1
0 performs the function of swinging when replacing the magnetic drum 2 in a cassette type, thereby momentarily moving the magnetic head 4 away from the outer peripheral surface of the magnetic drum 2.

Although a preferred embodiment of the present invention has been described in detail above, it goes without saying that the present invention is not limited to such a configuration. A magnetic head lever is not necessarily required, and the guide member may be a groove of a predetermined shape into which a pin is loosely fitted.

Further, in order to attach the lead wire to the magnetic head 4, it is preferable to attach it as shown in FIG. The magnetic head 4 is inserted into the magnetic head storage case 5 and fixed. At this time, a spacer 22 is pushed into the gap between the two to prevent play. Therefore, using the spacer 22, a bendable protruding piece 24 is integrally formed at the end thereof, and the protruding piece 24 is bent while the lead wire 26 is along the surface of the spacer 22. Then, the lead wire 26 is pressed and fixed from the outside.
In this way, not only is handling easier, but no force is applied to the connection between the magnetic head 4 and the lead wire, so there is no risk of wire breakage, and reliability is further improved.

Since the present invention is a magnetic head movable range limiting mechanism configured as described above, even if the magnetic head control mechanism fails and the magnetic head goes out of control, the magnetic head can be reliably moved at a predetermined position. Therefore, there is no risk of damaging the magnetic head, its drive mechanism, or the magnetic recording medium layer, and it can be easily restored, and it is mechanically extremely simple, durable, and reliable. The practical effect is extremely large in that a device with high performance can be obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing one embodiment of the magnetic head movable range limiting mechanism according to the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a side view thereof, and Fig. 4 is a diagram showing a lead wire to the magnetic head. It is an explanatory view showing an example of a mounting structure. 2...Magnetic drum, 4...Magnetic head, 7...
Pin, 8... Guide plate, 10... Magnetic head lever, 11... Magnetic recording medium layer, 13... Concave portion for stopper.

Claims (1)

[Scope of utility model registration request] A magnetic head that performs a track selection operation in a direction parallel to the rotational axis of the magnetic drum and is pressed against the outer circumferential surface of the magnetic drum by the elastic force of a spring, a pin that protrudes from a storage case of the magnetic head, and a guide member through which the tip of the pin is guided, and the guide member has a stopper recess into which the pin can be inserted and locked in order to regulate the movable range of the magnetic drum at a position corresponding to the vicinity of the end of the magnetic drum at both ends of the guide member. A movable range limiting mechanism for a magnetic head, characterized in that it has a structure in which: