Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
1999-07-16
2002-11-19
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S434000, C029S721000, C029S737000, C029S760000
Reexamination Certificate
active
06481085
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for manufacturing a disc cartridge accommodating therein a disc serving as an information-recording medium, and to a disc cartridge.
2. Description of the Related Art
Optical discs or magnetic discs are accommodated in cartridges so as to facilitate handling.
FIG. 30
is an exploded perspective view showing an example of a conventional disc cartridge. A disc cartridge
110
includes a disc
120
as an information-recording medium, a cartridge
130
in which the disc
120
is rotatably accommodated, and a shutter
140
slidably attached to the cartridge
130
.
The disc
120
is formed of a synthetic resin, such as a polycarbonate resin, a polystyrene resin, a polyolefin resin, a polymethylmethacrylate resin, or a norbornene-based resin, or aluminum or glass, and is annular. The disc
120
has an optical recording layer or a magneto-optic recording layer
121
formed on a principal plane thereof, and a chucking hub (center core)
122
made of a magnetic metal is attached to the central section thereof.
The cartridge
130
is formed in the shape of a flat box by injection molding of a thermoplastic resin, such as an ABS resin and a polycarbonate resin. The cartridge
130
consists of an upper shell
131
and a lower shell
132
coupled by screws
133
. The upper shell
131
has a recording/reproducing opening
131
a
formed in the center of a front end (a leading end in a direction of insertion into a driving device) thereof, and first to fourth circular-arc ribs
131
b
to
131
e
formed on the same circumference of the periphery of the inner surface thereof. These ribs
131
b
to
131
e
forms a rigid circular disc accommodating section
131
f
for rotatably accommodating the disc
120
. The lower shell
132
has a recording/reproducing opening
132
a
, first to fourth circular-arc ribs
132
b
to
132
e
, and a circular disc accommodating section
132
f
similarly to the upper shell
131
, and a driving (spindle shaft-inserting) opening
132
g
to which the chucking hub
122
of the disc
120
faces is formed in the center of the disc accommodating section
132
f.
The shutter
140
is formed into a U-shape in cross section by punching and bending a thin metal sheet having a thickness of about 0.15 mm to 0.4 mm, such as a stainless steel sheet or an aluminum sheet, or by injection molding of an acetal resin. The shutter
140
consists of a pair of upper and lower shutter plate portions
141
and
142
superposed on the outer surfaces of the upper and lower shells
131
and
132
, and a connecting portion
143
for connecting one of the ends of the shutter plate portions
141
and
142
. The shutter plate portion
141
is formed so as to have a length capable of opening and closing the opening
131
a
of the upper shell
131
, and the shutter plate portion
142
is formed so as to have a length capable of opening and closing both of the openings
132
a
and
132
g
of the lower shell
132
.
The shutter
140
is slidably attached to the front end of the cartridge
130
in a state where legs
151
and
152
of a slide guide member
150
attached to the inner surface of the connecting portion
143
by screws
133
are engaged with a slide guide groove
132
h
provided in the lower shell
132
, and the slide guide member
150
is sandwiched by the upper and lower shells
131
and
132
, and is biased by a torsion coil spring
160
to keep the openings
131
a
,
132
a
, and
132
g
closed.
A shutter guide plate
170
for preventing an end of the longer shutter plate portion
142
from curling is attached to the outer surface of the lower shell
132
. An accidental erasure-protecting member
180
is attached on the inner surface of the upper shell
131
. The accidental erasure-protecting member
180
has lugs
181
on both side surfaces thereof, as shown in
FIG. 31
, and the lugs
181
are engaged with recesses
131
i
formed in the inner wall of the upper shell
131
.
The thus-constructed disc cartridge
110
is assembled in a clean room using an automated assembly line so that dust does not adhere to the surface of the disc
120
and does not enter the cartridge
130
during assembly, which would affect recording and reproducing. The upper and lower shells
131
and
132
are brought together and stocked so as not to deform after being subjected to injection molding, and are placed on the assembly line on a conveyor. First, the upper and lower shells
131
and
132
are divided in a first step, the shutter guide plate
170
is bonded to the outside of the lower shell
132
in a second step, and then the accidental erasure-protecting member
180
supplied from a part feeder is engaged with the inner surface of the lower shell
132
at a predetermined position in a third step. The slide guide member
150
supplied from the part feeder is engaged with the slide guide groove
132
h
of the lower shell
132
in a fourth step.
Then, the disc
120
having the chucking hub
122
attached thereto and being stocked in a disc stocker is accommodated in the disc accommodating section
132
f
of the lower shell
132
and thereafter, the upper shell
131
that has been supplied on the line in synchrony with the lower shell
132
is coupled to the lower shell
132
by screws
133
in a sixth step. The head of the shutter plate portion
142
is inserted into a space between the shutter guide plate
7
and the lower shell
132
, and holes of the connecting section
143
and the slide guide member
150
are coupled by the screws
133
. Finally, the torsion coil spring
160
supplied from the part feeder is attached to the shutter
140
to complete the disc cartridge
110
.
The disc cartridge
110
is sent to an inspection step to be subjected to recording/reproducing inspection. A disc cartridge
110
confirmed to have sufficient quality is sent to a packaging step to be packaged together with an index card and a label and is accommodated in a plastic case, etc., and is then sealed by a plastic film, etc., to be distributed commercially. On the other hand, a disc cartridge
110
that is determined to be defective follows the above assembly step in reverse to remove the disc
120
. Thereafter, swarf of tapping screws produced at the time of fastening screws is removed by high-pressure clean air, and the disc cartridge
110
is introduced in the assembly step again, and a new disc
120
is incorporated into the disc cartridge
110
.
In order to manufacture the above-described conventional disc cartridge
110
, it is necessary to install and maintain a long assembly line, and a large clean room having a high-performance clean air feeder for installing the assembly line.
In addition, adjustment of an overall tact (volume of production per unit time) is required to synchronize the manufacture of the disc
120
and the assembly of the disc cartridge
110
, resulting in a reduction in operational availability of the assembly line.
Furthermore, the disc cartridge
110
that is determined to be defective must follow the assembly step in reverse and follow the assembly step again. Therefore, not only are complicated operations required, but also components may be damaged and the yield of the components may be reduced when disassembling the disc cartridge
110
.
Furthermore, when the tapping screws for use in coupling the upper and lower shells
131
and
132
are repeatedly removed and fastened, coupling strength of the upper and lower shells
131
and
132
is lowered. Therefore, the upper and lower shells
131
and
132
must be destroyed when the disc cartridge
110
is determined to be defective a second time.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a method and apparatus for manufacturing a disc cartridge for which a large-scale manufacturing facility is not required and of which manufacturing efficiency is high, and to provide a disc cartridge.
According to a first aspect of the present invention, there is provided a method for manufacturin
Hong John C.
Hughes S. Thomas
Kananen, Esq. Ronald P.
Rader & Fishman & Grauer, PLLC
Sony Corporation
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