Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
1999-07-14
2002-08-20
Letscher, George J. (Department: 2652)
Dynamic magnetic information storage or retrieval
Record medium
In container
Reexamination Certificate
active
06437942
ABSTRACT:
BACKGROUND OF THE INVENTION:
a) Field of the invention
The present invention relates to a disc cartridge in which a shutter is arranged to open or close a record playback opening of a shell rotatably housing a disc-shaped recording medium and in which a spring force exerted by a shutter biasing spring biasing the shutter in a close direction can prevent the shutter from being projected from a front end surface of the shell.
b) Description of the related art
FIGS. 9 through 14
show a previously proposed disc cartridge, for example, a floppy disc cartridge.
The disc cartridge
101
includes: a disc-shaped recording medium
102
; a shell
103
rotatably housing the disc-shaped recording medium; a shutter
105
opening and closing a record playback opening
104
installed on upper and lower surfaces
103
a
and
103
b
of the shell
103
; and a spring
106
used for a biasing purpose of the shutter (a twisted coil spring) to bias the shutter
105
toward the opening
104
for the record playback purpose.
The shell
103
is provided with an upper surface
103
a
, a lower surface
103
b
, a front end surface
103
c
, and a recess
103
d
for attaching the shutter, the recess
103
d
constituting a shutter slide area. The above-described recess
103
d
is formed with the approximately same depth D as the thickness T of the shutter
105
.
The shutter
105
includes: first and second shutter plate portions
105
a
and
105
b
overlapped on the shutter attaching recess
103
d
of the upper and lower surfaces of the shell
103
; and a linkage plate portion
105
c
linked to each one end of the first and second shutter plate portions
105
a
and
105
b
and having an inner surface overlapped on the shutter attaching recess
103
d
of the front end surface
103
c
of the shell
103
. In addition, the second shutter plate portion
105
b
is provided with front and second slide guide projections
107
and
108
disposed on one end and the other end of the plate portion
105
b
in its shutter slide direction.
The above-described shutter
105
is attached on the shell
103
so that the first and second slide guide projections
107
and
108
are inserted into first and second slide guide grooves
109
and
110
and are slid along these slide guide grooves
109
and
110
.
The first and second slide guide grooves
109
and
110
are disposed on the upper surface
103
b
of the shell
103
in parallel to each other along the front end surface
103
c
of the shell
103
.
The shutter biasing spring
106
has one end
106
a
engaged to a spring engagement portion
111
installed on a side portion of the shutter
105
on which the first slide guide projection
107
is attached and has the other end
106
b
engaged to an inner wall of the shell
103
.
As typically shown in
FIG. 11
, a distance L
11
from an inner surface (a surface opposed against a linkage plate portion
105
c
) of the first slide guide projection
107
to an outer surface of the linkage plate portion
105
c
of the shutter
105
and a distance L
12
from an inner surface (the surface opposed against the linkage plate portion
105
c
) of the second slide guide projection
108
to the outer surface of the linkage plate portion
105
c
of the shutter
105
are formed to be equal to each other (L
3
11
=L
12
). In other words, both of the first slide guide projection
107
and the second slide guide projection
108
are arranged on the same straight line position in parallel to the linkage plate portion
105
c
of the shutter
105
.
In addition, a distance L
13
from the first slide guide groove
109
into which the first slide guide projection
107
is inserted to the front end surface
103
c
of the shell
103
and a distance L
14
from the second slide guide groove
110
into which the second slide guide projection
108
is inserted to the front end surface
103
c
of the shell
103
are formed to be equal to each other (L
13
=L
14
).
In other words, the first slide guide groove
109
and the second slide guide groove
110
are arranged on the same straight line position in parallel to the front end surface
103
c
of the shell
103
.
The shutter
105
is slidably attached on a shutter attaching recess
103
d
of the shutter
103
by inserting the shell
103
between the first and second shutter plate portions
105
a
and
105
b
from the front end surface
103
c
of the shell
103
and by inserting the first and second slide guide projections
107
and
108
into the first and second slide guide grooves
109
and
110
, respectively.
SUMMARY OF THE INVENTION
However, in the disc cartridge
101
described in the BACKGROUND OF THE INVENTION, the spring force exerted by the shutter biasing spring
106
causes the one end of the shutter
105
to which the spring
106
is engaged to be projected from the front end surface
103
c
of the shell
103
. Hence, the shell
103
becomes easy to be interfered against other parts. Dust becomes easy to be invaded into the shell
103
. Or, a clearance &dgr; is developed between the side portion of the shutter plate portions
105
a
and
105
b
and the side portion
103
e
of the shutter attaching recess
103
d
of the shell
103
. This clearance gives a user, to his eye, a kind of unstable sense of feeling and gives worse outer appearance.
Causes of the projection of the one end of the linkage plate portion
105
c
of the shutter
105
from the front end surface
103
c
of the shutter
103
was pursued.
As the result of this pursuit, one cause was determined.
That is to say, the cause was that the distance L
11
from the first slide guide projection
107
to the outer surface of the linkage plate portion
105
c
of the shutter
105
and the distance L
12
from the second slide guide projection
108
to the outer surface of the linkage plate portion
105
c
of the shutter
105
were formed to be mutually w the same value (L
11
=L
12
). In details, the cause was that the first slide guide projection
107
and the second slide guide projection
108
were arranged on the same straight line position in parallel to the linkage plate portion
105
c
of the shutter
105
. In addition, the cause was that a distance L
13
from the first slide guide groove
109
into which the first slide guide projection
107
was inserted to the front end surface
103
c
of the shell
103
and a distance L
14
from the second slide guide groove
110
into which the second slide guide projection
108
was inserted to the front end surface
103
c
of the shell
103
were formed to be mutually the same value (L
13
=L
14
). In details, the first slide guide groove
109
and the second slide guide groove
110
were arranged on the same straight line position in parallel to the front end surface
103
c
of the shell
103
.
As shown in
FIG. 12
, a (play) clearance (hereinafter, referred to as a play clearance) &dgr;
1
is provided between the first slide guide projection
107
and the first slide guide groove
109
and another play clearance &dgr;
2
is provided between the second slide guide projection
108
and the second slide guide groove
110
in order for the first and second slide guide projections
107
and
108
to be inserted into the first and second slide guide grooves
109
and
110
and to be slid smoothly thereon.
The play clearances &dgr;
1
and &dgr;
2
have mutually the same value. Hence, the shutter biasing spring
106
causes the shutter
105
to be pressed against the side portion
103
e
of the shutter attaching recess
103
d
of the shell
103
causes the shutter
105
to generate a resultant force to project the shutter
105
. At this time, one end of the linkage plate portion
105
c
of the shutter
105
is projected from the front end surface
103
c
of the shell
103
by a distance quantity which is approximately the same as the play clearance &dgr;
1
.
To suppress the projection, magnitudes of the play clearances &dgr;
1
and &dgr;
2
may be reduced.
However, the reduction of the play clearances &dgr;
1
and &dgr;
2
, in turn, worsens a slide guide ability of the shutter
Bell Boyd & Lloyd LLC
Letscher George J.
Sony Corporation
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