Dynamic optical information storage or retrieval – Dynamic mechanism optical subsystem – Chassis base supporting transducer carriage
Reexamination Certificate
2000-11-21
2004-08-10
Davis, David (Department: 2652)
Dynamic optical information storage or retrieval
Dynamic mechanism optical subsystem
Chassis base supporting transducer carriage
Reexamination Certificate
active
06775837
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a head lifting device for moving a magnetic or optical head toward and away from a data-recording disk such as a magnetic disk, optical disk, MO (magneto-optical) disk. It also relates to a disk apparatus incorporating such a head lifting device.
2. Description of the Related Art
Conventional head lifting devices are disclosed in JP-A-6(1994)-20326, U.S. Pat. No. 5,500,838, JP-B2-8(1996)-31264 and JP-B2-8(1996)-10499 for example. Among these, the first three documents disclose similar head lifting mechanisms, in which a head-supporting arm is caused to pivot about a predetermined axis. The last document discloses a different type of mechanism from those disclosed in the first three documents.
Specifically,
FIG. 23
of the accompanying drawings shows the principal components of a magneto-optical disk apparatus disclosed in JP-A-6(1994)-20326. As seen from the figure, the conventional disk apparatus includes a magnetic head
90
and a head-supporting arm
91
. The magnetic head
90
is attached to the free end of the arm
91
. The opposite end or base end of the arm
91
is formed with a through-hole
92
into which a horizontal pin
93
is inserted. Thus, as shown in the figure, the arm
91
is vertically pivotable about the pin
93
, thereby moving the head
90
toward or away from the MO disk D. When the magnetic head
90
is held the uppermost position, the MO disk D is easily loaded into or unloaded from the disk apparatus. To perform data-writing or data-reading with the MO disk D, the arm
91
is caused to pivot to the lowermost position, so that the head
90
is held adjacent to the disk D.
FIGS. 24A and 24B
show the principal components of a magneto-optical disk apparatus disclosed in JP-B2-8(1996)-10499. As shown in
FIG. 24A
, the conventional disk apparatus includes a horizontally movable frame
94
and an elastic head-supporting arm
95
attached to the upper part of the frame
94
. The downwardly diagonal arm
95
carries a magnetic head
90
at its lower end, to position the head
90
adjacent to the MO disk D. The conventional disk apparatus is also provided with a stationary pin
96
protruding horizontally under the upper part of the frame
94
. The position of the pin
96
is adjusted so that it comes into contact with the arm
95
when the frame
94
is moved in the Na-direction shown in FIG.
24
B. Thus, as the frame
94
is moved in the Na-direction, the elastic arm
95
will bump into the pin
96
and consequently be flattened, as shown in the figure. As a result of this, the magnetic head
90
, attached to the lower end of the arm
95
, will be brought away from the MO disk D.
The above-described conventional disk apparatuses have been found disadvantageous in the following points.
In the first type of conventional apparatus shown in
FIG. 23
, it is necessary to provide some play between the pin
93
and the through-hole
92
for allowing smooth pivotal movement of the arm
91
. Due to this play, however, the positioning of the head
90
relative to the recording surface of the disk D tends to become inaccurate. To address this problem, the conventional apparatus is provided with an upright positioning pin
98
to engage with an elongated opening
97
formed in the arm
97
. Here again, some play needs to be provided between the pin
98
and the opening
97
, whereby the problem of inaccurate positioning of the head
90
will remain unsolved.
In the second type of conventional apparatus shown in
FIGS. 24A and 24B
, the above-described inaccurate positioning of the head will not be a problem. Disadvantageously, however, the head-supporting arm
95
may lose its initial elasticity after it has been repeatedly deformed through contact with the pin
96
. Since this problem is apt to be exacerbated as the arm
95
is bent to a greater extent, the movable range of the magnetic head
90
cannot be made large enough to facilitate the loading and unloading of the Disk D.
SUMMARY OF THE INVENTION
The present invention has been proposed under the above-described circumstances, and its object is to provide a simple structure which allows a read/write head to move a great distance (or stroke) relative to a data storage disk without compromising the accuracy of head positioning procedure.
According to a first aspect of the present invention, there is provided a head lifting device includes: a head-supporting member including a first end and a second end opposite to the first end; a head element supported by the first end of the head-supporting member; a base member for supporting the second end of the head-supporting member; and connecting means for pivotably connecting the base member to the second end of the head-supporting member. The connecting means includes at least one hole and at least one protrusion held in sliding engagement with the hole. The protrusion as a whole is prevented from passing through the hole.
With such an arrangement, no play will be provided between the protrusion and the hole. Thus, it is possible to accurately perform the positioning of the head element (carried by the head-supporting member) relative to e.g. a data storage disk. When such accurate positioning is possible, a magnetic head (an example of the claimed head element) can be made appropriately small, since there is no need to generate an unduly strong magnetic field to compensate for the otherwise inaccurate head positioning operation. Further, in such an instance, the coil inductance of the magnetic head can be made smaller, which is advantageous to improving the data transfer speed.
The head element may be an optical head other than a magnetic head.
According to a preferred embodiment of the present invention, the hole may be formed in the head-supporting member, while the protrusion may be formed on the base member. Alternatively, the hole may be formed in the base member, while the protrusion may be formed on the head-supporting member.
Preferably, the protrusion may include a spherical portion engaging with the hole. In this manner, the head-supporting member can pivot smoothly on the protrusion.
Preferably, the hole may have a circular or triangular configuration.
According to another preferred embodiment of the present invention, the protrusion may include anon-spherical portion. For instance, the protrusion may be a prism or pyramid. Here, the “pyramid” is defined as a solid or hollow shape with a square or triangular base and sloping sides that meet in a point at the top. Of course, the protrusion may have other configurations.
According to another preferred embodiment of the present invention, the connecting means may include first and second protrusions spaced from each other in a direction perpendicular to a line connecting the first and the second ends of the head-supporting member. The first and the second protrusions may be engaged with a single hole of the connecting means.
According to still another preferred embodiment of the present invention, the connecting means may be provided with first and second holes engaging with the first and the second protrusions, respectively.
According to still another preferred embodiment of the present invention, the hole and the protrusion may be elongated in a direction perpendicular to a line connecting the first and the second ends of the head-supporting member.
The protrusion may be formed separately from the head-supporting member and the base member. Alternatively, the protrusion may be formed integral with either one of the head-supporting member and the base member.
The protrusion may be made up of a solid metal ball used in e.g. a ball bearing. Instead of having a completely round figure, the protrusion may include a flat surface to be adhered to either one of the head-supporting member and the base member.
Preferably, the base member may be provided with a stopper to abut against a particular portion of the head-supporting member for facilitating the positioning of the head element.
Preferably, the head lifting device of the pre
Davis David
Fujitsu Limited
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