Dynamic magnetic information storage or retrieval – Head mounting – For shifting head between tracks
Reexamination Certificate
1998-11-25
2001-02-06
Klimowicz, William (Department: 2754)
Dynamic magnetic information storage or retrieval
Head mounting
For shifting head between tracks
C451S036000, C451S104000
Reexamination Certificate
active
06185076
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a magnetic head carriage, so called a head arm member or an access arm, for a hard disc drive formed by drawing or extrusion molding, more particularly to a carriage, the head arm member or access arm, with novel surface finish polish.
2. Description of Related Art
FIG. 1
is a perspective view of a magnetic head carriage as a head arm member or an access arm for a hard disc drive, hereinafter HDD is used, as an example. The carriage
1
includes a base member
1
a
and a plurality of plate members
1
b
as arm members formed integrally as a comb shape extending parallel in the outer direction from the base member
1
a
. A plurality of slits
1
f
are provided between the plate members
1
b
. A support shaft hole
1
c
is provided in the base member
1
a
, and an opening
1
e
for lessening the weight of the plate members
1
b
and a head installation hole
1
d
for installing the magnetic head are formed by cutting work on the top of each plate member
1
b
formed in the triangle shape or the like viewed from the upper direction. A plurality of head arm members
1
b
move between a plurality of discs in the protrudent direction, and the magnetic head installed in the top position is capable of reading information from the disc.
Here, one example, in which the shape of the carriage is different from the above described type, of the head arm portion of the magnetic disc is explained using
FIGS. 2A
,
2
B and
3
.
In the disc apparatus, a magnetic head is provided on the both sides or a single side of each magnetic disc in a plurality of magnetic discs. The magnetic head is installed in the pointed end of a suspension, and the suspension is installed in the top position of a carriage arm of an actuator assembly. Thus, the carriage arm, namely the magnetic head, is capable of being positioned in an appointed position by moving in the radius direction of the magnetic disc when the actuator of the actuator assembly is driven.
FIG. 3
is a perspective view of one example of the actuator assembly. In the actuator assembly
6
shown in
FIG. 3
, one side of a rotating shaft
5
is a driving portion
7
as the actuator and the other side is a carriage arm
8
rotating by the rotating shaft
5
. The driving portion
7
includes a voice coil
9
installed on a coil supporting plate
7
a
and a flexible printed circuit (FPC)
7
c
supported by a fixed portion
7
b
. Here, the numeral
7
d
means a pressure plate. The necessary numbers of carriage arms are provided corresponding to the numbers of the magnetic discs, and a magnetic head assembly
11
is installed in two sides or one side of the top installation portion
10
as shown in
FIGS. 2A and 2B
, thus the magnetic head
13
is capable of being positioned in the appointed position in the radius direction of the magnetic disc
4
. In the top installation portion
10
, a hole
10
a
is provided for installing the magnetic head assembly
11
on two sides or one side of the top installation portion
10
. Here, a magnetic arm means a block in which the magnetic head assembly
11
is installed in the actuator assembly
6
.
This invention relates to the magnetic head carriage described above made of improved materials. Usually, in the above described carriage, the opening
1
e
or the hole
1
d
is formed by cutting work materials after drawing or extrusion molding. In
FIG. 1
, a bur would be made around each plate portion
1
b
of above mentioned magnetic head carriage or in angle positions of holes
1
c
and
1
d
, and opening
1
e
, by cutting work, drawing, or extrusion molding. If the apparatus is assembled without treating the bur, there are problems in which the bur damages the disc surface by contacting with the disc surface and the disc and the head would be damaged because the bur would be caught between the disc and the head and cutting work scraps would drop on the disk. Thus, it should be carefully done to remove the bur and chamfer. Further, a film or an alien substance would adhere to the plate members
1
b
in the hard disc assembly process for the next process, thus it should be securely done to remove and clean the film and alien substance. For the hard disc drive, the disc rotates at a high speed and the gap between the magnetic head and the magnetic disc is 0.005 to 0.10 &mgr;m as an ultra-minute mechanism, thus such high precision rate that thickness dimensional tolerance of each plate member
1
b
and form tolerance for each plate should be under 20 &mgr;m is required to the above described carriage. The above described precision is so high that HDD will crush even if tiny dust exists in the gap between the magnetic disc and the magnetic head when the disc is running because the magnetic head and the magnetic disc are damaged and the chip would damage the magnetic head and the magnetic disc as a synergy effect.
In the head arm member
1
of the above described
FIG. 1
, however, it is impossible to automatically remove the bur made in the angle position of the hole
1
c
,
1
d
, and
1
e
of the plate member
1
b
with comb shape because a processing tool is not able to enter inside. Thus, many people cannot help cleaning the bur using a brush, then actually a large amount of money is spent for just only finishing process. Further, in the method of removing the bur by a human being's hand, it might be impossible to make processing for the inside of the above described head arm member
1
arranged in a complicated manner. Thus, there is a problem in which the head arm member
1
is not capable of being small and light because the structure of the head arm member
1
should be changed to the simpler structure. Further, this type of problem is found not only in the above described head arm member
1
, but also in surface processing or surface treatment for precision parts having the hole or the opening inside and the narrow wide slit outside, thus there is another problem in which the capability of producing a variety of products is disturbed.
Further, there are electrolytic polishing, a shot method, or an ultrasonic method as a polishing method for those portions. There are defective points in which dimensional tolerance of each plate member is not capable of being solved if the bur is removed enough by electrolytic polishing and inside processing is impossible although outside surface processing is possible by the shot method. Further, the ultrasonic method does not have enough power to remove the bur, thus processing becomes uneven. Thus, those processing methods are not capable of being used because the surface shape inside the comb teeth made with a micron accuracy is destroyed. Unavoidably, those portions are processed by a brush by the human being's hand using abrasive material. Thus, there have been defective points in which polish efficiency has been very bad and the cost would be high because one hundred percent test has been required since the polish processing has been made by the human being's hand. Further, the bad quality rate based on processing has been high.
The applicant discloses a method and an apparatus in which the bur of the surface beyond one's reach or inside nonmagnetic parts is removed using a machine using magnetic beam processing additionally, so called magnetic polishing.
Here, surface finishing polish for the above described carriage based on the conventional manual processing is explained in detail. Conventionally, firstly, the big bur which can be seen by one's eye is removed roughly by rotating a metal brush as shown in
FIGS. 4A
,
4
B, and
4
C. The above described metal brush has the structure in which a number of wire brushes grow densely in a prop
14
in the same circle direction as shown in
FIGS. 4A
,
4
B, and
4
C, and, as shown in
FIG. 4A
, polish processing is made in such a way that the prop is rotated in the arrow direction and then the above described carriage is pressed by one's hand from one side. After the above described rough polish processing is finished,
Shinbo Yoshinori
Shinmura Takeo
Armstrong, Westerman Hattori, McLeland & Naughton
Klimowicz William
Kyoei Denko Co., Ltd.
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