Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
2002-01-02
2002-07-23
Letscher, George J. (Department: 2655)
Dynamic magnetic information storage or retrieval
Record medium
In container
Reexamination Certificate
active
06424491
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a magnetic tape cartridge formed by ultrasonic welding.
In
FIG. 1
, reference numeral
1
designates the magnetic tape cartridge. The magnetic tape cartridge
1
is constructed as follows: A magnetic tape
20
is wound on a reel
3
which is formed by combining upper and lower reels
4
and
5
together by ultrasonic welding. The reel
3
is rotatably accommodated in a cartridge casing which is formed by combining upper and lower cartridges
2
a
and
2
b
together with screws
19
.
The upper reel
4
is made of polycarbonate resin containing glass fibers. The upper reel
4
has an upper flange
4
a
, and a recess at the center which has a boss section
4
b
extended towards the center. The upper flange
4
a
has a gear
4
y
on its outer cylindrical surface.
The aforementioned recess has a cylindrical rib, in which a ring-shaped bearing
6
is press-fitted. And a spring plug
7
is fixedly press-fitted in the central hole formed in the bearing. A reel spring
8
is mounted on the spring plug
7
, to push downwardly the aforementioned reel
3
and hold the reel
3
rotatably.
The lower reel
5
is made of polycarbonate resin, and has a lower flange
5
a
which has a hole at the center around which an ultrasonic welding rib
5
b
is formed. The lower reel
5
is combined with the shoulder of the aforementioned boss section
4
b.
When the cartridge is not in use, the reel
3
is locked by reel brakes
50
and
51
so that it may not be turned unintentionally, the reel brakes
50
,
51
which are suitably urged by braking torsion springs
12
. When the magnetic tape cartridge
1
is not in use, the magnetic tape
20
has been completely wound on the reel
3
, and the leader tape.
21
connected to the end of the magnetic tape is locked to the end of a hook
18
which is provided near the side wall of the cartridge.
The opening, through which the magnetic tape
20
is pulled out is designed as follows: That is, a lid
30
, which is swingable in a cartridge plane, is provided while being suitably urged by a torsion spring
15
. When the cartridge is not in use, the lid
30
is locked by a locking member
40
(which is suitably urged by a compression spring
16
) so that it may not be swung. On the side which is opposite to the side where the lid
13
is provided, the cartridge has a write protect
17
.
The aforementioned leader tape
21
is engaged with an engaging means adapted to lead the magnetic tape
20
in the tape path of the recording and reproducing device. The leader tape
21
is fastened to the magnetic tape
20
, for instance, by splicing.
In the above-described magnetic tape cartridge
1
, the upper and lower reels
4
and
5
are combined together by ultrasonic welding as follows. As was described before, the annular rib
5
b
, which is formed along the annular edge of the circular opening formed at the center of the lower flange
5
a
, is engaged with the shoulder of the lower portion of the boss section
4
b
. Under this condition, while a predetermined pressure is applied to the upper and lower reels
4
,
5
, those reels
3
are subjected to ultrasonic excitation, so that the rib
5
b
is molten to combine the upper and lower reels
4
and
5
together.
In this welding operation, the upper reel
4
is set below the lower reel
5
. More specifically, the upper reel
4
is fixedly set, and the lower reel
5
is placed on the upper reel
4
from above. Under this condition, the upper reel
4
is subjected to ultrasonic pressure excitation. As the rib
5
b
is molten, the surface of the lower reel
5
is brought into contact with the shoulder of the upper reel
4
. From this fact, it is determined that the welding operation has been accomplished.
FIG. 2
shows the conventional ultrasonic welding portions of the aforementioned reel
3
. The boss section
4
b
of the upper reel
4
comprises a shoulder
4
c
, and a protrusion
4
d
which is extended from the shoulder
4
c
and is smaller in diameter than the shoulder
4
c
. Along the outer annular edge of the shoulder
4
c
, a stopper ring
4
e
is integrally provided which is slightly higher in level. That is, the upper reel
4
is in the form of a shallow-bottomed container as a whole. In addition, between the stopper ring
4
e
and the protrusion
4
d
, turn-preventing stoppers
4
f
are provided in such a manner that they are diametrically opposite to each other, and are flush with each other.
On the other hand, the rib
5
b
of the lower reel
5
has cuts
5
d
at angular intervals of 90°. When, with the central hole of the lower reel
5
engaged with the protrusion
4
d
of the upper reel
4
, the lower reel
5
is turned, the cuts
5
d
are engaged with the turn-preventing stoppers
4
f
. When, under this condition, the reel
3
is subjected to pressure excitation, the rib
5
b
is molten. The molten portion of the rib
5
b
, being absorbed in the shallow-bottomed annular groove, is spread uniformly. As a result, the surface of the lower flange
5
a
is brought into contact with the upper surface of the stopper ring
4
e
. Thus, the welding operation has been accomplished.
In the above-described conventional magnetic tape cartridge, the lower flange
5
a
and the stopper ring
4
e
are almost in line contact with each other; that is, they are considerably small in contact area. Hence, it is difficult to weld the upper and lower reels
4
,
5
together in such a manner that they are high in parallelism. This fact results in a so-called surface play.
In the case where the tape
20
is wound on the reel
3
, the tape winding operation is carried out with the upper flange
4
a
and the boss section
4
b
of the upper reel
4
as a reference. In this case, since the upper flange
4
a
and the boss section
4
b
are formed as one unit by injection molding, the tape
20
can be wound on the reel
3
with high accuracy. However, in the case where the tape winding operation is carried out based on the lower reel
5
and the boss section
4
b
which suffer from the surface play, it is difficult to achieve the tape winding operation with high accuracy.
If, with the reel
3
, the welding area is increased in the direction of the diameter, the width of the stopper ring
4
e
should be increased. However, in this case, the molten portion flows out of the shallow-bottomed groove; that is, the resultant product is unacceptable. In addition, the welding area is not large enough; that is, the upper and lower reels
4
,
5
are not satisfactorily welded together.
In the case of the conventional reels
3
shown in
FIG. 2
, the lower reel
5
is prevented from turning as follows: That is, in order to prevent the lower reel
5
from turning, after the lower reel
5
is set on the upper reel
4
, the lower reel
5
must be turned at most 90°. Accordingly, it is impossible to subject the upper and lower reels
4
,
5
to ultrasonic work immediately after the lower reel
5
is set on the upper reel
4
. Furthermore, a metal mold for forming the turn-preventing stoppers
4
f
and the cuts
5
d
is intricate in configuration. Therefore, there is a strong demand for the provision of turn-preventing means which replaces the turn-preventing stoppers
4
f
and the cuts
5
d.
Furthermore, in the conventional magnetic tape cartridge, as shown in FIG.
3
(
a
) the rib
5
a
is molten starting from its end by pressure excitation, and the molten resin spreads gradually in the shallow-bottomed groove according to the pressure.
However, in practice, as indicated by a group of dots in FIG.
3
(
b
), owing to the pressure which is applied simultaneously when the melting operation starts a part of the molten resin sometimes flows over the stopper ring
4
e
to the outer periphery of the boss section
4
b
. The molten resin thus caused to over-flow is solidified as cooled, thus sticking onto the outer periphery. Hence, when the tape
20
is wound on the reel
3
, the winding center is shifted from the true center; that is, the resultant product is unacceptable.
SUMMARY OF THE INVENTION
Accordingl
Fuji Photo Film Co. , Ltd.
Letscher George J.
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