Dynamic magnetic information storage or retrieval – Head – Core
Reexamination Certificate
2001-04-03
2003-09-23
Davis, David (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Core
Reexamination Certificate
active
06624969
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head, which is used in a floppy disc drive (a downwardly compatible high recording density FDD) having both a standard (i.e., low) recording density and a high recording density, or the like, and which is compatibly applicable to a plurality of recording media having respective recording densities different from each other.
2. Description of the Related Art
An example of a magnetic head used in a downwardly compatible high recording density FDD is shown in
FIGS. 6
to
8
.
A magnetic head
30
shown in
FIGS. 6
to
8
is of a type bearing two magnetic cores
31
and
32
(for instance, a magnetic core of 120 MB type and a magnetic core of 2 MB type) having respective recording densities different from each other, and the magnetic cores
31
and
32
form respective closed magnetic circuits independent of each other. The magnetic cores
31
and
32
are inserted and positioned in slits
37
and
38
formed in a slider
35
, and fastened with glass or the like. After a sliding surface of a magnetic recording medium is formed by machining such as cutting and polishing, coil windings
33
and
34
are applied on a window portion of the magnetic core respectively.
In addition, a conventional type of magnetic head without so-called compatibility is shown in
FIGS. 9 and 10
. The magnetic head shown in
FIGS. 9 and 10
is of a so-called separated type as will be described later and used in an FDD for a standard recording density (a normal FDD). In this magnetic heads a read/write core
42
and an erasing core
43
are accommodated and held in an opening
41
formed in a substantially rectangular slider
40
. A back yoke
44
is connected to the read/write core
42
, the erasing core
43
and the slider
40
. The back yoke
44
forms a closed magnetic circuit in association with the read/write core
42
and the erasing core
43
, and supports the slider
40
.
The back yoke
44
is generally comprised of a substantially rectangular back yoke body
45
which is a little larger than a slider
40
, a first leg portion
46
, a second leg portion
47
and a third leg portion
48
which are all standing upright in a line on one face of the back yoke body
45
, and an outer circumference wall portion
49
standing upright on the outer circumference portion of the back yoke body
45
and connected to the slider
40
.
The first leg portion
46
is connected to the read/write core
42
thereby forming a closed magnetic circuit with the read/write core
42
. The third leg portion
48
is connected to the erasing core
42
thereby serving to form a closed magnetic circuit with the erasing core
42
. The second leg portion
47
is connected to a joint portion of the read/write core
42
and the erasing core
43
thereby serving in common to form respective closed magnetic circuits with the read/write core
42
and the erasing core
43
.
As mentioned above, since the back yoke body
45
is formed a little larger than the slider
40
, a space
50
, which is not covered by the slider
40
, is formed on an upper surface of the outer circumference wall portion
49
. A resin
51
is applied to this space
50
to fix the slider
40
and the back yoke
44
together.
A read/write coil
52
having three lead wires
52
a,
52
b
and
52
c
is mounted on the first leg portion
46
. An erasing coil
53
having two lead wires
53
a
and
53
b
is mounted on the third leg portion
48
.
Two cut-outs
54
a
and
54
b
are formed on the outer circumference wall portion
49
. Three lead wires
52
a
,
52
b
and
53
c
of the read/write coil
52
are let through the cut-out
54
a
to the outside, and two lead wires
53
a
and
53
b
of the erasing coil
53
are let through the cut-out
54
b
to the outside.
In the magnetic head shown in
FIGS. 9 and 10
, the resin
51
is applied to the space
50
of the upper surface of the outer circumference wall portion
49
. It is difficult to control an amount of application, and the resin may be accidentally attached to the upper surface of the slider
40
, or a poor adhesion may be caused due to an insufficient amount of resin.
Further, since the magnetic head shown in
FIGS. 9 and 10
has one kind of recording density applicable to a recording medium and is not compatible, it is not convenient. Further, three lead wires
52
a
,
52
b
and
52
c
of the read/write coil
52
are let through one cut-out
54
a
and two lead wires
53
a
and
53
b
of the erasing coil
53
are let together let through one cut-out. This makes it happen that wires with respective different roles such as a starting end of coil or finishing end of coil are mistaken for each other when wiring. So, careful work is required thereby lowering workability and productivity.
The present invention has been made in light of the above circumstance, and an object thereof is to provide a magnetic head, which enables workability for coil termination to be increased, prevents mistake in wiring and which is compatibly applicable to recording media having respective recording densities different from each other.
According to a first aspect of the present invention, in a magnetic head comprising a slider which slides on a magnetic recording medium, and accommodates and holds a plurality of magnetic cores having respective gaps and having recording densities different from each other in a plurality of openings formed on a sliding side, respectively, and a back yoke which comprises a substantially plate-like back yoke body provided parallel to the slider, a plurality of inner pillars standing upright on the back yoke body and four walls standing upright on respective edges of the back yoke body and connected to the slider and which is connected to the magnetic cores thereby forming closed magnetic circuits, holds the slider, and includes a plurality of coils provided on the plurality of inner pillars provided corresponding to the plurality of magnetic cores, respectively, the four walls include cut-outs in number equal to or larger than number of lead wires of the plurality of coils.
According to a second aspect of the present invention, in the first aspect, at least three cut-outs are provided on each of the four walls.
According to a third aspect of the present invention, in the first or second aspect, the back yoke, the inner pillar and the walls are integrally molded using a soft magnetic material.
According to a fourth aspect of the present invention, in any one of the first to third aspects, at least two of the plurality of magnetic cores are for a standard recording density floppy disc drive and for a high recording density floppy disc drive, respectively.
REFERENCES:
patent: 5402397 (1995-03-01), Ohmori et al.
patent: 6075681 (2000-06-01), Egawa et al.
patent: 6226148 (2001-05-01), Egawa et al.
patent: 6297930 (2001-10-01), Egawa et al.
patent: 11149608 (1999-06-01), None
Egawa Motoji
Oishi Shigeyuki
Davis David
Minebea Co. Ltd.
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