Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Cartridge system
Reexamination Certificate
2001-05-14
2003-05-27
Nguyen, John Q. (Department: 3654)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Cartridge system
C360S132000, C242S610400
Reexamination Certificate
active
06568619
ABSTRACT:
TECHINICAL FIELD
The present invention relates, in a magnetic tape cartridge where a single reel with magnetic tape wound thereon is rotatably housed within a cartridge case, to the reel of the magnetic tape cartridge.
BACKGROUND ART
In magnetic tape cartridges, which are being used as storage media that are employed in external storage units for computers, etc., there is known a type where a single reel with magnetic tape wound thereon is rotatably housed within a cartridge case. This magnetic tape is employed to archive data for computers, etc. Since important information has been stored, the magnetic cartridge is constructed so that problems, such as tape jamming, etc., do not occur and that the magnetic tape is not pulled out of the cartridge case unexpectedly when not being used, such as when being archived, etc.
The reel is provided with a reel gear which meshes with the driving gear of the rotation means of a cartridge drive mechanism so that it is rotatable and also provided with a magnetic metal plate for keeping the meshed state therebetween.
Hence, when rigidly attaching the aforementioned metal plate to the reel, it is preferable to hold this metal plate to the inside surface of a metal mold and provide the metal plate and the reel integrally by insert molding, because they can be easily manufactured. However, in the insert molding which injects molten resin from a gate provided in the center of the central hole of the annular metal plate, the resin injected under high pressure flows directly to the inner peripheral surface of the central hole of the metal plate. Because of this, there is a possibility that the resin will enter the space between the metal plate and the inside surface of the metal mold and therefore the metal plate cannot be held at a predetermined position in the reel. There is another possibility that in a molded reel product where resin has flowed to the top surface side of the metal plate because of the above-mentioned entrance of resin, it cannot be assured that the metal plate is parallel with the magnet of the rotation means of the cartridge drive mechanism and therefore chucking failure will occur.
If the injecting pressure is reduced to prevent the above-mentioned entrance of resin, a portion insufficiently filled with resin will occur and thus the dimensional precision of the molded produce will be reduced.
The present invention has been made in view of the problems mentioned above. Accordingly, it is a first object of the present invention to provide a reel of a magnetic tape cartridge which can be manufactured by insert molding, without reducing pressure under which resin is injected and without causing resin to enter the space between the metal plate and the inside surface of the metal mold.
The above-mentioned reel, incidentally, is constructed of a cylindrical hub with tape wound on the outer peripheral surface thereof, and flanges extending in disc form from both ends of the hub so that the wound tape is interposed therebetween. Generally, in the case of constituting the reel with resin molded components, one of the two flanges and the hub are molded integrally and the other flange molded as a separate body is rigidly attached to the end portion of the hub.
The rigid attachment between the hub and the flange is usually performed by an ultrasonic welding method using weld bosses or an energy director. The ultrasonic welding shortens manufacturing time, and is low in running cost because a portion melted from a molded component is used as a binder, so ultrasonic welding is now being widely used for manufacturing reels.
Thus, in the rigid attachment of the reel by ultrasonic welding, it is difficult to assure satisfactory attachment precision with enhancements in recording density and recording precision. That is, if data is recorded with high density, the lateral deflection of tape will have an influence on recording and reproducing characteristics. For this reason, the traveling height precision of tape is required to be very strict. In the ultrasonic welding of the hub and the flange which are resin-molded components, however, it is extremely difficult to rigidly attach the flange to the hub at a right angle to the rotation axis of the hub with high precision. Because of this, the development of a high-precision reel has been hastened so that it can satisfactorily meet the high-density recording being required in recent years. In addition, as the recording capacity of the magnetic tape is increased, as described above, the tension of winding a magnetic tape that is wound on the reel becomes greater. Because of this, it is necessary to make the strength of attachment between the hub and the flange stronger.
The aforementioned problems with the ultrasonic welding will be described in detail. Rigid attachment type reels are shown in FIG.
10
and
FIGS. 11 and 12
. The example of
FIG. 10
is a type in which the longitudinal end portions of magnetic tape are respectively fixed to two reels housed in the cartridge case and the magnetic tape is wound from one of the reels onto the other. In the reel, a hub
153
formed integrally with one flange
154
, and another flange
155
formed as a separate body, are connected together by ultrasonic welding. Within the cylindrical hub
153
with an outer peripheral surface on which magnetic tape is wound, six weld bosses
156
protruding in a direction parallel to the rotation axis of the hub
153
are provided at regular intervals in the circumferential direction. On the other hand, at positions corresponding to the weld bosses
156
, a disc flange
155
has transmission holes
157
into which the weld bosses
156
are inserted. The flange
155
is placed on the hub
153
so that the upper ends of the weld bosses
156
inserted into the transmission holes
157
project from the flange
155
. Then, with the annular tip end surface of a welding horn pressed against the upper end portions of the weld bosses
156
, ultrasonic waves are applied to the upper portions of the weld bosses
156
to melt the weld bosses
156
. The melted weld bosses
156
are flattened so that the flange
155
is rigidly attached to the hub
153
.
Similarly, in the reel shown in
FIGS. 11 and 12
, a hub
153
formed integrally with one flange
154
, and another flange
155
formed as a separate body, are connected together by ultrasonic welding. Within a cylindrical hub
153
, three weld bosses
158
are provided at regular intervals in the circumferential direction. A disc flange
155
has transmission holes
159
into which the weld bosses
158
are inserted. As with the aforementioned, the flange
155
is placed on the hub
153
so that the weld bosses
158
are inserted into the transmission holes
159
. Then, the upper end portions of the weld bosses
158
are melted and flattened with the 3-point annular tip end surface of a welding horn so that the flange
155
is rigidly attached. Note that the above-mentioned weld bosses
156
and
158
may be welded by heating.
In the rigid attaching by the weld bosses
156
and
158
, however, pushing force will remain exerted on the central portion of the attached flange
155
and deform the flange
155
, if the welding by the welding horn is too strong. If the welding is too weak, the flange
155
will not be satisfactorily attached due to underwelding of the weld bosses
156
and
158
and chatter of the flange
155
against the hub
153
will occur. Furthermore, if a plurality of weld bosses
156
and
158
are unequally welded, a warp will develop in the flange
155
. If such a reel rotates, deflection of the flange
155
will occur and accordingly deflection of the magnetic tape will occur. Thus, it is difficult to manage welding conditions suitably.
FIGS. 13 and 14
show a rigid attachment type reel having an energy director. A flat fixing portion
160
in the form of a ring is formed in an end surface near the outer peripheral surface of a cylindrical hub
153
on which magnetic tape is wound. At the inner peripheral surface of a disc flange
155
, a generally triangular
Shiga Hideaki
Tsuyuki Seiji
LandOfFree
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