Vibration Absorbing Support Assembly for a Disc Memory

This invention relates to a disc memory device such as a magnetic disc storage.

In a movable head type magnetic disc storage used as a memory device, a magnetic head is positioned at a desired track on the surface of a magnetic disc through servo control. In positioning, as soon as a request for calling a specified piece of information on the magnetic disc surface has been issued, the magnetic head is moved at a high speed radially of the magnetic disc so as to decrease the call time. Accordingly, an actuator of relatively high mechanical output energy is used for moving the magnetic head and for positioning.

Accordingly, when the high output actuator which is fixedly mounted on a base is energized for quick movement of the magnetic head in response to a call instruction, it is affected by abrupt acceleration/deceleration control to undergo a shock, and consequently a carriage carrying the magnetic head and the base are forced to vibrate, followed by occurrence of off tracking (or a tracking error) in the magnetic disc memory device.

With the trend toward increased recording density, the above disadvantage has been more aggravated. A prior art technique for coping with this problem is found in a proposal disclosed in, for example, U.S. Pat. No. 3,643,242 wherein a magnetic circuit block for a voice coil motor serving as an actuator is made in the form of a movable structure which can absorb the above-mentioned shock. Disadvantageously, the movable structure is massive and a device of this proposal becomes large-sized and complicated by incorporating the massive movable structure. In addition, the dust generated from the movable structure can not be shielded sufficiently.

An object of this invention is to provide a disc memory device which can absorb vibrations generated in response to acceleration/deceleration of an actuator without being affected by the above prior art disadvantages.

To accomplish the above object, according to this invention, the whole of a disc memory assembly incorporating an actuator is made in the form of a movable structure which is movable in the same direction as an operative direction of the actuator, so that vibrations generated upon acceleration/deceleration of the actuator may be absorbed by the whole assembly.

FIG. 1 is a perspective view of an embodiment of a magnetic disc memory device according to the invention; and

FIG. 2 is a sectional view showing the internal construction of the FIG. 1 device.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, a magnetic disc memory device has a disc memory assembly 1 including a housing 4 in which a magnetic disc 2 recorded with data and a recording/reproducing magnetic head 3 are accomodated, and a linear drive actuator 5 for moving the magnetic head 3. The magnetic disc 2 is fixedly mounted on a spindle 7 rotated by a motor 6. The actuator 5 is a voice coil motor comprised of a voice coil 8 connected to the magnetic head 3 inside the housing 4, and a magnet 9.

This invenion particularly features a vibration damping structure as best seen in FIG. 1. Specifically, the disc memory assembly 1 is movably supported on a pair of rigid shafts 20 by means of a pair of front guides 18 and a pair of rear guides 19. The assembly 1 can therefore be moved in a direction in which the actuator 5 is operative, namely, the voice coil 8 is moved. For smooth movement, a slide bushing 17 is fitted in each of the guides. The pair of shafts 20 are fixedly mounted, at their opposite ends, to a rigid base 16 and the magnetic disc assembly 1 is supported on the base 16.

When the actuator is accelerated or decelerated abruptly, a reaction force is first generated in the magnet 9 and then transmitted to the housing 4, with the result that the whole of the disc memory assembly is affected by the reaction force. Under the influence of this reaction force, the disc assembly 1 moves on the shafts 20 to thereby absorb the reaction force. Of course, the operative direction of disc assembly 1 due to the reactive force is in exact opposition to the operative direction of the actuator. Since the actuator is operated randomly in general services, the reaction force exerted on the disc memory assembly 1 becomes random and the assembly 1 tends to place itself frequently, on the average, at around the midpoint of the shafts 20.

For special services, however, springs 21 may be applied on opposite ends of one shaft 20 (or both shafts as necessary) to thereby absorb a reaction force due to movement of the actuator and also rapidly bring the assembly 1 back to the midpoint after movement of the assembly 1. To prevent resonance, the spring 21 is required to have a spring constant which is designed not to be equal to a period of movement timing of the actuator. (Such consideration is unnecessary when the spring 21 is not used.)

As is clear from the foregoing description, since the disc memory assembly is so configured as to be movable in the operative direction of the actuator for the purpose of absorbing vibrations generated in response to acceleration/deceleration of the actuator, a very compact, inexpensive high-density magnetic disc memory device can be obtained.

To increase storage capacity, several of the megnetic disc memory devices may be packaged in a common enclosure or several of the disc assemblies may be mounted to a common base like the base 16 in the same manner as in FIG. 1. In this way, interaction between the devices or assemblies can be minimized and a highly reliable memory system can be materialized. Furthermore, in contrast to the prior art vibration absorbing movable structure which is disadvantageously provided interiorly of the device, the external movable structure in accordance with the invention will not at all raise the problem of dust generation, thus improving reliability of the disc memory device.

The present invention, therefore, is well adapted to carry out the object and attain the advantages mentioned as well as those inherent therein.