Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Cartridge system
Reexamination Certificate
1999-12-02
2001-12-04
Nguyen, John Q. (Department: 3653)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Cartridge system
C360S132000
Reexamination Certificate
active
06325316
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to and claims priority, under 35 U.S.C. § 119, from Japanese Patent Application No. 10-345698, filed on Dec. 4, 1998, the entire contents of which is hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tape cartridge for digital recording with a DDS (Digital Data Storage), a DAT (Digital Audio Tape) or another medium used.
2. Discussion of Background
In such a type of conventional tape cartridge, a pair of hubs with a tape-shaped medium wound thereon are rotatably supported in a casing. In FIGS.
8
(
a
),
8
(
b
), and
8
(
c
), a bottom plan view, a cross-sectional view taken along line
8
b
—
8
b
of FIG.
8
(
a
), and a top plan view, respectively, show an example of conventional hubs. Each hub
103
comprises a dram
103
a
at an outermost side and an inner cylinder
103
b
formed inside of and integrally with the drum
103
a
The drum
103
a
is a portion that has a tape-shaped medium wound on an outer periphery thereof.
The inner cylinder
103
b
has a bore
103
e
formed therein to accept a driving shaft of a recording/reproducing device. The hub
103
has teeth
103
d
formed on an outer periphery of an upper portion thereof to be engageable with a pawl of a hub brake. When the pawl of the hub brake have leading edges engaged into between teeth
103
d
, the hub
103
is locked against rotation.
In FIGS.
9
(
a
) and
9
(
b
), a plan view and a cross-sectional view taken along line
9
b
—
9
b
of FIG.
9
(
a
), respectively, show a state wherein the driving shaft of a recording/reproducing device is inserted into the bore
103
e
of the inner cylinder
103
b
of the hub
103
. The inner cylinder
103
b
has six projections
103
c
provided on an inner peripheral surface thereof in a peripheral direction at equal intervals to extend in a vertical direction. The driving shaft
110
has a core or root
111
and three engaging portions
112
. The engaging portions
112
are provided on an outer peripheral surface of the driving shaft
110
at equal intervals to extend in the vertical direction. When the driving shaft
110
is inserted into the bore
103
c
of the hub
103
, the respective engaging portions
112
are located between projection
103
c
to transmit rotation from the driving shaft
110
from the engaging portions
112
to the projections
103
c
, rotating the hub
103
./
Recently, there have been demands to provide a tape cartridge having larger storage capacity for data storage. In order to increase the storage capacity, a tape-shaped medium is required to have a thinner thickness than conventional ones, allowing a greater tape length to be accepted. However, such a tape-shaped medium has a thickness limitation of about 5 &mgr;m in terms of production technique. From this viewpoint, the outer diameter of the drum
103
a
is required to be smaller than the conventional ones, allowing the tape length to be extended under the limitation.
The drum
103
a
is subjected to slow thermal shrinkage since the drum is thicker than surrounding parts. As a result, a phenomenon that a recess is formed by thermal shrinkage occurs in the drum in many cases. In order to prevent this phenomenon from occurring, preformed recesses
103
f
are formed in the drum. In order to prevent the occurrence of a recess due to thermal shrinkage in the drum
103
a
at the time of molding the drum, the preformed recesses
103
f
are formed in upper and lower portions of the drum to ensure that the drum
103
a
has a proper wall thickness. If the outer diameter of the drum
103
a
is decreased, the preformed recesses
103
f
are made smaller, creating problems in that the strength of portions of a mold for forming the preformed recesses
103
f
is weakened and that the form accuracy of the drum
103
a
is lowered.
It is an object of the present invention to make the outer diameter of drums smaller to wind a longer tape-shaped medium thereon without lowering the strength of a mold and the form accuracy of the drums.
In order to solve the problem, the present invention provides a tape cartridge comprising a pair of hubs, the respective hubs including respective drums for winding a tape-shaped medium thereon and respective inner cylinders with respective driving shaft insertion bores for accepting respective driving shafts of a recording/reproducing device, the respective inner cylinders being integrally molded with the respective drums; a casing including upper and lower halves, the casing rotatably supporting the hubs therein; driving shaft insertion holes formed in the casing, the respective driving shaft insertion holes accepting the respective driving shafts; a slider for slidably covering the respective driving shaft insertion holes; a hub brake engageable with the hubs; teeth provided on upper portions of the respective hubs so as to be engageable with the hub brake; recesses formed between the respective drums and the respective inner cylinders, the recesses having upper ends thereof opened; the respective drums having respective outer peripheral surfaces between adjoining teeth conformed to inner peripheral surfaces of the respective recesses; and the respective teeth having portions thereof extending into the respective recesses.
SUMMARY OF THE INVENTION
In the tape cartridge, the recesses may be provided at plural locations at certain intervals, reinforcing ribs may be provided between adjoining recesses to connect lower ends of the respective teeth and an inner peripheral surface of the respective drums, and the reinforcing ribs may be provided at locations except for locations where projections are provided, the projections being provided on the inner peripheral surface of the respective inner cylinders so as to be engageable with the respective driving shafts.
In the tape cartridge, the respective inner cylinders may have respective top plates formed on respective upper ends thereof to cover the respective driving shaft insertion holes.
In accordance with the present invention, the recesses are preformed between the respective drums and the respective inner cylinders, the respective drums have the respective outer peripheral surfaces between adjoining teeth conformed to the inner peripheral surfaces of the respective recesses, and the respective teeth have portions thereof extending into the respective recesses. This arrangement can reduce the outer diameter of the respective drums with the respective drums having a proper wall thickness and with the recesses having a certain volume.
In a preferred mode of the present invention, the reinforcing ribs are provided between adjoining recesses so as to be provided at locations except for the provision of the projections. This arrangement can prevent not only a recess from occurring due to thermal shrinkage in the drums but also the drums from leaning even if a tape-shaped medium is wound on the drums.
In another preferred mode of the present invention, the respective inner cylinders have the respective top plates formed on the respective upper ends thereof This arrangement can increase the strength of the inner cylinders with the teeth provided on the outer peripheral surfaces thereof. In addition, this arrangement can improve the moldability of the hubs by having a mold provided with a gate at a central portion on an outer surface of the top plate.
REFERENCES:
patent: 4719529 (1988-01-01), Oishi et al.
patent: 5647551 (1997-07-01), Ikeda et al.
patent: 675 790 (1990-10-01), None
patent: 0 565 888 (1993-10-01), None
patent: 2 223 479 (1990-11-01), None
patent: 2-049031 (1990-12-01), None
Hashizume Kenji
Ikebe Masaru
Miyazaki Yukio
Nguyen John Q.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
TDK Corporation
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