JPH0249029Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a support structure for a magnetic head in a magnetic drum device that records and reproduces analog/digital signals on multiple tracks. This invention relates to a magnetic head support structure in which the head is always brought into contact with the magnetic drum in an appropriate direction without being tilted.

Announcement systems using magnetic drum devices are known for automobile OK monitors, vending machines, various terminal devices, elevators, various public notice devices, and the like. In these applications, there are requirements such as being able to directly record and play back audio information, and being able to randomly access a large amount of audio information. This is because the above requirements can be met by recording and reproducing information on each track via the track.

In this case, it is desirable to make the magnetic drum device as small and lightweight as possible. In order to make the magnetic drum smaller (smaller in diameter) for the same recording capacity, it is necessary to reduce its circumferential speed, and the resulting drop in output level can be achieved by pressing the magnetic head against the surface of the magnetic drum. This can be compensated to some extent by means of reducing gap loss.
Therefore, the magnetic head must always be pressed against the magnetic drum with as constant a pressure as possible, and must also be in direct contact with the surface of the magnetic drum at the position of the head gap. This is because if the magnetic heads are in contact with each other at an angle, gap loss will occur and the output will decrease accordingly. Furthermore, it is necessary to hold the magnetic head in such a way that the above-mentioned good contact state can be maintained at all times, even against play when the carriage member moves and shocks and vibrations applied to the entire device.

A conventional magnetic head support mechanism has a structure in which the magnetic head is attached to the tip of a leaf spring, the base end of the leaf spring is fixed to a carriage member, and the elasticity of the leaf spring presses the magnetic head against the surface of the magnetic drum. Something was warm. However, devices installed using only leaf springs require delicate adjustments for each device in order to keep the contact pressure of the magnetic head constant, and in addition, the magnetic drum is slightly eccentric. This has the disadvantage that the contact pressure of the magnetic head changes significantly, causing uneven rotation, wear, and changes in output level.

The uniformity of the contact pressure of the magnetic head can be improved by using a soft leaf spring, but then the weight of the magnetic head cannot be supported sufficiently, and when the magnetic head performs a track selection operation, the surface of the magnetic drum It may happen that the product is pressed in a tilted state. A similar defect occurs when a magnetic head is supported using only a coil spring instead of a soft leaf spring.

An object of the present invention is to provide a support structure for a movable magnetic head that can overcome the drawbacks of the prior art.

The present invention, which can achieve the above objectives, has a magnetic head at the tip so that when the magnetic head is pressed against the magnetic drum surface with a constant pressure, the head gap always contacts the magnetic drum surface in the correct direction. A rotatable arm supports a leaf spring to which the head is attached, and a coil spring is attached to the tip of the arm, so that the elastic force of the coil spring presses the magnetic head against the magnetic drum.

Hereinafter, the present invention will be explained in more detail based on the drawings. FIG. 1 is an explanatory diagram showing an embodiment of the present invention. The magnetic head support mechanism located near the magnetic drum includes a carriage member 1 that is movable in a direction parallel to the rotational axis of the magnetic drum for track selection operation, and a base end rotatably attached to the carriage member 1. A leaf spring 3 having one end fixed to the tip of the arm 2, a magnetic head 4 fixed to the other end of the leaf spring 3, and a rotating force applied to the tip of the arm 2. The magnetic head 4 supported by the leaf spring 3 slides against the outer peripheral surface of an opposing magnetic drum (not shown) by the elastic force of the coil spring 5.

The carriage member 1 has its guide tube 7 loosely fitted into two guide rods 6 (however, only one is shown in FIG. 1), which are usually arranged in a direction parallel to the rotation axis of the magnetic drum. Therefore, it is possible to slide only in the length direction of the guide rod 6 without rotating.For example, although not shown, the stepper motor and the feed screw rod attached to its shaft are attached to the carriage member. The carriage member 1 is moved by screwing into a female threaded portion provided therein and rotationally driving a stepper motor, so that track selection can be performed. The arm 2 supports the leaf spring 3 in such a manner that its base end (rotation axis) is located closer to the magnetic head 4 and its tip end is located in the opposite direction to the magnetic head 4. is subjected to a tensile force. With this configuration, it becomes possible to install the leaf spring 3 at the end of the carriage member 1, and when a magnetic drum and a support structure for a magnetic head are provided together, an extremely preferable arrangement can be adopted. Note that the leaf spring 3 used here has a strong enough springiness to sufficiently support the weight of the magnetic head 4 attached to its tip.

The operation of the magnetic head support structure constructed in this way will be explained with reference to FIGS. 2 and 3. The contact pressure of the magnetic head 4 to the magnetic drum 8 is mainly determined by the coil spring 5. Since the change in elastic force of the coil spring 5 is relatively small with respect to the amount of expansion and contraction, even if the magnetic drum 8 is eccentric, or there is some play between the guide rod 6 and the carriage member 1, it will not be affected. It can be absorbed to obtain a substantially uniform pressing force. In addition, the leaf spring 3 supporting the magnetic head 4 absorbs vibrations, shocks, etc., and when a track is selected, the magnetic head tilts as shown by the broken line in FIG. When a force acting on the magnetic head to prevent contact with the layer 9), the leaf spring 3
As a result of this action, the magnetic drum 8 is brought into contact with the surface of the magnetic drum 8 precisely at the position of the head gap, as shown by the solid line in FIG.

Since the present invention is configured as described above,
Due to the elastic force of the coil spring, even if the magnetic drum is eccentric, the magnetic head is always pressed against the surface of the magnetic drum with a nearly constant force, and due to the action of the leaf spring, even during head track selection operation. The practical effects are extremely great, such as being able to accurately contact the magnetic drum surface at the position of the head gap, improving the reliability of track selection, and stabilizing the output.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention;
The figure is an explanatory diagram showing the operation, and FIG. 3 is an explanatory diagram showing the head contact situation. 1...Carriage member, 2...Arm, 3...
Leaf spring, 4...Magnetic head, 5...Coil spring.

Claims (1)

[Scope of utility model registration request] A carriage member movable for track selection, an arm rotatably attached to the carriage member at its base end, a leaf spring having one end fixed to the distal end of the arm, and the leaf spring. The outer periphery of a magnetic drum includes a magnetic head fixed to the other end and a coil spring that applies rotational force to the tip of the arm, and the magnetic head supported by a leaf spring faces each other due to the elastic force of the coil spring. A support structure for a movable magnetic head, characterized in that it comes into sliding contact with a surface.