Dynamic magnetic information storage or retrieval – Head – Coil
Reexamination Certificate
2001-07-25
2003-11-04
Miller, Brian E. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Coil
C360S125020
Reexamination Certificate
active
06643094
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head device for use in floppy disk devices or the like.
2. Description of the Related Art
In a magnetic recording method in which a leakage flux from a magnetic recording medium is introduced from a gap into a magnetic head including a coil for a readback process, a magnetic flux is also introduced into a magnetic head core due to an external magnetic field from a motor, a power supply or the like, and noise may be generated by the magnetic flux causing errors.
To cope with the above noise, there are provided various types of magnetic head devices in which a shield ring (shield portion) made of a magnetic material such as ferrite or permalloy is disposed at an outer circumference of a magnetic head core in order to guide magnetic fluxes from external magnetic fields into the shield ring thereby preventing the magnetic fluxes from going into the magnetic head core.
As one example of the aforesaid type of magnetic head devices, there is a magnetic head device in which a magnetic head core, a slider, and a coil wound on a bobbin are disposed in a shield ring, a terminal block having terminal pins to which lead wires of the coil are connected is formed integrally with the bobbin at one end of a narrow extension whose width is smaller than the width of a flange of the bobbin, the narrow extension of the bobbin fits in a slit of the shield ring to thereby allow the terminal block to be disposed outside the shield ring, and the slit of the shield ring is kept to a minimum size required to eliminate the influence of external noise.
As one example of a bobbin and a terminal block integrated with the bobbin for use in such a magnetic head device as described above (hereinafter referred to as “integration bobbin”), the inventor of this application disclosed an integration bobbin in Japanese Patent Application Laid-open No. Hei 11-53707. The integration bobbin will be described with reference to FIG.
7
.
In
FIG. 7
, lead wires
53
from a coil
52
on a bobbin proper
51
of the integration bobbin
50
are guided toward a terminal block
56
passing over a narrow extension
55
extending from a bobbin flange
54
formed at one end of the bobbin proper
51
. The bobbin flange
54
, the narrow extension
55
and the terminal block
56
are integrally formed. The width of the narrow extension
55
is made slightly larger than the width of a slit (opening portion) in a shield ring (not shown).
A projection
57
is provided on the terminal block
56
for guiding the lead wires
53
. The lead wires
53
from the coil
52
are bound on respective terminal pins
58
a
to
58
c
by way of the projection
57
.
In recent years, magnetic disk devices tend to become higher in density and smaller in size, and in association with this tendency magnetic head devices for use in the magnetic disk devices have been also made smaller and thinner. In addition, the magnetic head devices are required to be constructed to allow a certain tolerance in dimensions in consideration of variance in assembly and components.
However, in the prior art shown in
FIG. 7
, the projection
57
is provided on the terminal block
56
, which increases the longitudinal dimension of the magnetic head device, whereby a tolerance in dimension relative to a shutter of a floppy disk is reduced. Thus, depending on an accuracy of assembling magnetic head devices, there may be a risk such that the floppy disk and the projection
57
on the terminal block
56
are in contact with each other causing scratches or damages to magnetic heads of the magnetic head device or the floppy disk.
SUMMARY OF THE INVENTION
The present invention has been made in light of the above, and it is an object of the present invention to provide a magnetic head device which can achieve the same effect as the prior art devices without providing a projection for guiding lead wires.
According to a first aspect of the present invention, in a magnetic head device in which a shield ring comprises a magnetic head core, a slider and a coil wound on a bobbin, one flange of the bobbin extends (flange extension) in one direction for a predetermined length maintaining its width, a narrow extension having a smaller width than the flange extension is formed integrally on an end face of the flange extension, a terminal block having terminal pins to which lead wires of the coil are connected is formed integrally at an end of the narrow extension and in which the narrow extension of the bobbin fits in a slit provided in the shield ring making the terminal block to be positioned outside the shield ring, a guide recess for guiding the lead wires of the coil is formed on a distal end of the terminal block, and the lead wires are connected to the terminal pins through the recess.
According to a second aspect of the present invention, in the first aspect of the invention, the terminal block is of a substantially rectangular shape, the guide recess is formed on a face of the distal end of the terminal block away from the narrow extension, and the terminal pins are provided on a lower face of the terminal block, which is present on a side of an outward face of the one flange opposite to a face in contact with the coil.
According to a third aspect of the invention, in the second aspect of the invention, the narrow extension is formed such that one side thereof is recessed from one side of the flange extension thereby defining a cutout while another side thereof is flush with another side of the flange extension, and an angle &thgr; formed between the one side of the flange extension and a line segment connecting a point defined by a side line of another flange in line with the one side of the flange extension intersecting with an end line of the another flange positioned toward the terminal block and a point defined by a bottom corner of an inlet of the guide recess toward the cutout is set to meet &thgr;>tan
−1
(b/a) where a is a length of the flange extension and b is a depth of the cutout.
According to a fourth aspect of the present invention, in any of the first to third aspects of the invention, the depth of the guide recess ranges from 0.1 mm to 0.5 mm.
According to a fifth aspect of the present invention, in any of the first to third aspects of the invention, the depth of the guide recess gradually decreases from the inlet for lead wires toward the terminal pins.
According to a sixth aspect of the present invention, in any of the first to fifth aspects of the invention, the width of the guide recess is small at the inlet on a lead wire introduction side of the guide recess and gradually increases toward the terminal pins.
REFERENCES:
patent: 4879620 (1989-11-01), Yamashita
patent: 5148342 (1992-09-01), Kato
patent: 5402397 (1995-03-01), Ohmori et al.
patent: 5459629 (1995-10-01), Wakasugi
patent: 5497283 (1996-03-01), Kato
patent: 5629821 (1997-05-01), Wakasugi et al.
patent: 5889642 (1999-03-01), Egawa et al.
patent: 5963402 (1999-10-01), Egawa et al.
patent: 6075681 (2000-06-01), Egawa et al.
patent: A 11-53707 (1999-02-01), None
patent: 11053707 (1999-02-01), None
Miller Brian E.
Minebea Co. Ltd.
Oliff & Berridg,e PLC
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