Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Cartridge system
Reexamination Certificate
2000-07-21
2001-11-20
Rivera, William A. (Department: 3653)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Cartridge system
C360S132000
Reexamination Certificate
active
06318658
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tape cassette including a casing which accommodates a tape reel wound with a tape and a cover member for protecting the tape, and more particularly to a tape cassette having front, upper and rear covers as cover members.
2. Related Background Art
A tape cassette including three pieces of cover members, i.e., front, upper and rear covers, has thitherto been known as, e.g., a DVC (Digital Video Cassette). In this type of tape cassette, the tape exposed outside the cassette in front of the casing is protected by being covered with the front, upper and rear covers when unused.
FIGS. 4A and 4B
are side views each showing the conventional cassette tape. As illustrated in
FIGS. 4A and 4B
, a front cover
103
is rotated when using the tape cassette
101
, and an upper cover
104
and a rear cover
105
move interlocking with the rotation of the front cover
103
and thus open the front surface of a casing
102
.
As indicated by a broken line in
FIG. 4B
, when the front cover
103
rotates upward, the upper cover
104
rotates about rotary spindles
106
, and moves rightwards in
FIG. 4B
while being guided at its guide spindles
104
a
along a guide groove
107
of the casing
102
. Simultaneously, the rear cover
105
rotates about its rotary spindles
105
a
and moves upwards while being guided at its guide spindles
105
b
along a cam groove
108
of the casing
102
. As shown in
FIG. 4A
, when the front cover
103
rotates farther upwards, the front surface of the casing
102
opens, and at the same time the tape
100
is released from a state of being protected by the front, upper and rear covers. At this time, a front side end of the rear cover
105
moves while depicting a trajectory x by a one-dotted chain line in FIG.
4
A.
As to a configuration of the guide groove for guiding the upper cover described above, Japanese Patent Application Laid-Open Publication No. 8-87861 discloses that the upper cover slides easier with the guide grooves having a smaller inclined angle, however, it is undesirable that the rear cover, if under 35 degrees, interlocking therewith might interfere with the tape.
Japanese Patent Application Laid-Open Publication No.11-110947 discloses that a slide resistance caused by opening the cover member decreases when an opening angle of the front cover is within a range of 0 to 30 degrees, and gives a specification value for a relation between an opening angle of the front cover and a height of the rear cover when the cover member of the tape cassette opens (FIGS.
18
and
19
).
As described above, in the tape cassette having the cover body composed of three pieces of the cover members, the cover body is easy to open, but there are problems in terms of the interference between the rear cover and the tape and a restriction based on the specification requirement of the height of the rear cover when the cover body opens. It is required that those factors be taken and a graph, wherein there is given a specification value of a height of the rear cover
105
from a bottom surface of the casing with respect to a rotation angle &ggr; of the front cover
103
in FIG.
4
B. In the tape cassette in the prior art, the rear cover has a height C satisfying the specification requirement. In the example shown in
FIG. 4B
, the height C of the rear cover is 4.6 mm as compared with a specification value of 4.0 mm when the rotation angle &ggr; is 35 degrees. Further, as shown in the graph in
FIG. 5
it can be comprehended that the height C of the rear cover tends to approximate the specification value when the rotation angle (opening angle) &ggr; is within a range of 20 to 45 degrees.
The prior art tape cassette shown in
FIGS. 4A and 4B
has, however, a problem in which an inclined angle &thgr; of an inclined portion
107
a
of the guide groove
107
for guiding the upper cover
104
is approximately 50 degrees with a large resistance caused when opening the cover body, and cuttings are produced in the guide groove and the guide spindles by this resisting force as the case may be. Such being the case, for reducing the resistance when opening the cover body, as shown in
FIG. 6
, if the inclined angle &thgr; of the inclined portion
107
a
of the guide groove
107
is set stepwise smaller than 50 degrees, as shown in
FIG. 7
, the front cover opens at the rotation angle &ggr; within a range of 25 to 45 degrees, and the height C of the rear cover approximates the specification value. Then, when the inclined angle &thgr; comes to 30 degrees, the specification value is not met. In the example shown in
FIG. 6
, when the rotation angle &ggr; of the front cover is 35 degrees, the height C of the rear cover is 4.2 mm as compared with the specification value of 4.0 mm at the inclined angle &thgr; of 35 degrees.
Then, as shown in
FIGS. 8A and 8B
, if contrived so that the inclined angle of the inclined portion
108
a
of the cam groove
108
for guiding the rear cover
105
is increased and the rear cover
105
is moved fast up to a high position, in an example in
FIG. 8B
, when the rotation angle &ggr; of the front cover is 35 degrees, the height C of the rear cover is 4.7 mm for the specification value of 4.0 mm at the inclined angle &thgr; of 30 degrees, which sufficiently satisfies the specification requirement. While on the other hand, however, as indicated by a trajectory x′ of a front side end of the rear cover
105
in
FIG. 8A
, the rear cover
105
gets close to the tape and interferes with the tape with the result that the tape might undesirably be damaged.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide a tape cassette capable of ensuring the opening and closing of a cover body, satisfying a specification requirement of a height of a rear cover, and preventing the rear cover from interfering with a tape.
To accomplish the above object, according to one aspect of the invention, a tape cassette includes a pair of tape reels wound with a tape-like member, a casing for accommodating the tape reels in a rotatable manner, and a cover member for protecting the tape-like member stretched outside the casing when the cassette is not used. The cover member includes a front cover having side plates pivotally supported on side surfaces of the casing, and a front plate, rotating together with the side plates, for covering a front surface of the tape-like member before the front surface of the casing when the cassette is not used, an upper cover, connected on its one end side to an upper end portion of the front cover and interlocking with a rotation of the front cover while being guided along guide portions provided in the side surface of the casing on its other end side, for covering from above the tape-like member stretched outside the casing when the cassette is not used, and a rear cover, connected at its upper end portion to the upper cover and interlocking with the movement of the upper cover while being guided by a cam portion provided in the casing, for covering a rear surface of the tape-like member when the cassette is not used. The front cover is biased in such a direction as to cover the front surface of the tape-like member and rotates against the biasing force when using the cassette, whereby the upper cover and the rear cover move interlocking with each other to open the front surface of the casing. The guide portion includes a horizontal portion provided on a rear side of the cassette, and an inclined portion provided on the side of the front surface of the cassette and inclined to the horizontal portion. The cam portion includes a first inclined portion, inclined to the lower surf ace of the casing, for guiding the rear cover so as to move away from the tape-like member when the front cover starts rotating to open the front surface of the casing, a second inclined portion, inclined much slant than the first inclined portion, for subsequently guiding the rear cover upwards of the casing, and a perpendicular portion inclined much sla
Kaneda Hiroshi
Okamura Masatoshi
Darby & Darby
Rivera William A.
TDK Corporation
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