Tape cassette having means for locking reels thereof

A tape reel lock and release device having gear portions formed around outer peripheries of a pair of tape reels rotatably provided within a cassette half, a tape reel locking member having a slider portion which is slidably spring-biased by a spring between the pair of tape reels within the cassette half in the direction in which it is engaged with the gear portions of the pair of tape reels and a pair of engaging members coupled to a top end of the slider portion to be engaged with the gear portions of the tape reels, the pair of engaging members being curved at their tip ends toward the gear portions and having hinge portions formed at their base end portions so as to be displaced in the direction in which the pair of engaging members approach each other and an extending operation member protrusively formed on the cassette half so as to be located between the engaging members and entering, when the tape reel locking member is slidably moved toward the reel locking direction, between the engaging members to extend the engaging members toward the gear portions of the tape reels. Thus, when the engaging members are engaged with the gear portions of the tape reels, the slackening of a magnetic tape wound around the tape reels can be absorbed and the tape reels can be prevented from being rotated inadvertently.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to a tape cassette having means for 
locking reels thereof and, more particularly, is directed to a tape reel 
lock and release device of a tape cassette which can, upon non-use of tape 
cassette, prevent tape reels from being rotated unintentionally by 
engaging members formed on a reel locking member with gear portions of the 
tape reels. 
2. Description of the Prior Art 
In a tape cassette, when tape reels rotatably provided within cassette 
halves are rotated upon non-use, a magnetic tape wound around the tape 
reels is slackened. The assignee of the present application has previously 
proposed a tape reel lock and release device which can prevent tape reels 
from being rotated inadvertently. This previously-proposed tape reel lock 
and release device is disclosed, for example, in Japanese Patent 
Application No. 62-78747. 
An enlarged, plan view forming FIG. 1 illustrates an example of such tape 
reel lock and release device. As Fig. 1 shows, a reel locking member 4 
having a pair of engaging members 3, 3 to be engaged with gear portions 2 
of a tape reel 1 is spring-biased toward the tape reels 1 by a spring 9. 
Hinge portions 5 and 6 are each formed on the base portions and 
intermediate portions of the pair of engaging members 3 and 3. Further, a 
central rib 7 is protrusively formed from a cassette half 8 at the 
position in which the engaging members 3 are engaged with the gear 
portions 2. This central rib 7 extends the engaging members 3, 3 toward 
the tape reels 1, causing the tape reels 1 and the engaging members 3 to 
be engaged with each other. 
In this prior art tape reel lock and release device, however, the gear 
portions 2 and the engaging members 3 can be engaged positively to some 
extent. In this engagement, the engaging members 3, 3 push the tape reels 
1 in the direction shown by arrows a in FIG. 1 such that the tape reels 1 
are moved toward the tape eject opening side. There is then a risk that 
the magnetic tape (not shown) wound around the tape reels 1 will be 
slackened. If the magnetic tape is slackened as described above, when the 
tape cassette, for example, is ejected from a cassette loading portion of 
a video camera or the like, its lid portion will bite the magnetic tape. 
Therefore, as shown in FIGS. 2 to 4, the configuration of the central rib 7 
which extends the engaging members 3, 3 is modified, whereby while the 
reel locking member 4 is moved from its lock-released state shown in FIG. 
2 to its locking completion state shown in FIG. 4, the engaging members 3, 
3 come in contact with the central rib 7 as shown in FIG. 3, thus the 
engaging members 3, 3 being extended to be engaged with the gear portions 
2. Thereafter, the reel locking member 4 is slid further such that the 
engaging members 3, 3 rotate the tape reels 1 in the tape slack absorbing 
direction shown by arrows b in FIG. 4. Thus, upon locking, the tape slack 
can be absorbed. 
When the reel locking member 4 is slid relative to the central rib 7 as 
described above, the pair of engaging members 3 and 3 formed at the top of 
the reel locking member 4 are provided with hinge portions 6 and 6 at 
their intermediate portions so that the engaging members 3 and 3 can be 
displaced at their hinge portions 6 and 6. Thus, when the engaging members 
3 rotate the tape reels 1 in the tape slack absorbing directions b, the 
engaging members 3 are flexed at their hinge portions 6 formed at the 
intermediate positions thereof, thus the tape reels 1 cannot be rotated 
sufficiently in the tape slack absorbing direction b. 
Further, when the engaging members 3 rotate the tape reels 1 in the tape 
slack absorbing direction b, the engaging members 3 push the tape reels 1 
in the direction shown by arrows c in FIG. 4 with the result that their 
pushing forces weaken, swinging the engaging members 3 in the direction 
shown by arrows e in FIG. 5. There is then a risk that the engaging 
members 3 will come off from the gear portions 2 of the tape reels 1. 
Consequently, the tape reels 1 cannot be sufficiently prevented from being 
inadvertently rotated by the above-mentioned locking member 4. 
Furthermore, since the hinge portions 6 are formed on the intermediate 
portions of the engaging members 3, when the engaging members 3 are 
handled as assembly parts and/or attached to the tape cassette or the 
engaging members 3 are left for a long period of time under the reel lock 
releasing condition after they are incorporated in the tape cassette, the 
engaging members 3 are frequently deformed so that the tape reels 1 cannot 
be positively prevented from being rotated. 
OBJECTS AND SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide an 
improved tape reel lock and release device which can remove the defects 
encountered with the prior art. 
It is another object of the present invention to provide a tape reel lock 
and release device in which tape reels can be locked positively without 
slackening a magnetic tape. 
It is a further object of the present invention to provide a tape reel lock 
and release device which can positively prevent tape reels from being 
rotated unintentionally. 
It is a yet further object of the present invention to provide a tape reel 
lock and release device for use with a tape cassette of an 8 mm video 
camera. 
According to one aspect of the present invention, there is provided a tape 
reel lock and release device comprising: 
(a) gear portions formed around outer peripheries of a pair of tape reels 
rotatably provided within a cassette half of a cassette housing; 
(b) a tape reel locking member having a slider portion which is slidably 
spring-biased by spring-biasing means between said pair of tape reels 
within said cassette half in the direction in which it is engaged with 
said gear portions of said pair of tape reels and a pair of engaging 
members coupled to a top end of said slider portion to be engaged with 
said gear portions of said tape reels, said pair of engaging members being 
curved at their tip ends toward said gear portions and having hinge 
portions formed at their base end portions so as to be displaced in the 
direction in which said pair of engaging members approach each other; and 
(c) an extending operation member protrusively formed on said cassette half 
so as to be located between said engaging members of said tape reel 
locking member and entering, when said tape reel locking member is 
slidably moved toward the reel locking direction, between said engaging 
members to extend said engaging members toward said gear portions of said 
tape reels, wherein said engaging members are engaged with said gear 
portions of said tape reels thereby preventing said tape reels from being 
rotated inadvertently. 
The above, and other objects, features and advantages of the present 
invention will become apparent from the following detailed description of 
the preferred embodiments to be taken in conjunction with the accompanying 
drawings, in which like reference numerals identify like elements and 
parts.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be described with reference to the attached 
drawings. 
A partly cut-away plan view forming FIG. 6 illustrates a tape cassette for 
use in a so-called 8 mm video camera to which an embodiment of a tape reel 
lock and release device according to the present invention is applied. 
As FIG. 6 shows, in this tape cassette, an upper half 11 and a lower half 
12 each made of a synthetic resin are combined together to form a cassette 
housing 10 by some suitable means such as screws (not shown) and the like. 
A pair of tape reels 13 around which a magnetic tape T is wound are 
rotatably provided within the cassette housing 10. 
The magnetic tape T wound around the tape reels 13 is extended along a 
front opening portion 14 of the cassette housing 10 and pinched by lid 
members (not shown) at the inside of a front lid 15. Thus, when this tape 
cassette is loaded on a cassette loading portion of a video camera or the 
like though not shown, the front lid 15 and the lid members are moved 
upward to withdraw the magnetic tape T. 
This cassette housing 10 incorporates therein a tape reel lock and release 
device 20 of which the main portion is illustrated in FIGS. 6 to 10. The 
arrangement of this tape reel lock and release device 20 will be described 
with reference to FIGS. 6 to 10. 
Referring to the figures, gear portions 21 are formed on the outer 
peripheries of the pair of tape reels 13 that are rotatably provided 
within the upper and lower halves 11 and 12 of the cassette housing 10. 
A reel locking member 22 is located between the pair of tape reels 13 so as 
to be engaged with the gear portions 21. 
As shown, for example, in FIG. 7, the above-mentioned reel locking member 
22 is spring-biased by a spring 23 in the direction in which it is engaged 
with the gear portions 21 of the tape reels 13 and, this reel locking 
member 22 is supported between guide walls 24 so as to become freely 
slidable. 
Specifically, the reel locking member 22 is comprised of a slider portion 
25 slidably provided between the guide walls 24 and a pair of engaging 
members 26, 26 that are mounted on the top of the slider portion 25 so as 
to be engaged with the gear portions 21 of the tape reels 13, 
respectively. The engaging members 26 and 26 are curved in substantially 
C-letter configuration at their intermediate curved portions 26a so that 
their top portions form engaging nails 27, respectively. Hinge portions 28 
are respectively formed at the base portions of the engaging members 26 
and 26 so as to be displaced in the direction in which they approach each 
other. The engaging members 26 are coupled to the slider portion 25 via 
these hinge portions 28. The curved portions 26a of the engaging members 
26 are formed slightly thick in order to come in contact with an extending 
operation member 29 which will be described later. It is also possible 
that slightly thin portions 26b may be formed on the outside of the curved 
portions 26a to allow the engaging members 26 to function as limiters. 
Near the top portions of the guide walls 24 which slidably support the tape 
reel locking member 22, the extending operation member 29 is protrusively 
formed from the lower half 12 so as to oppose the engaging nails 27, 27 of 
the tape reel locking member 22. This extending operation member 29 
advances, when the tape reel locking member 22 is slidably moved in the 
reel locking direction, between the engaging members 26 and 26 to extend 
the engaging members 26 and 26 toward the gear portions 21 of the tape 
reels 13, whereby the engaging nails 27 are engaged with the gear portions 
21, thus the tape reels 13 being prevented from being rotated. 
As shown in FIG. 10, a step portion 30 is formed on the lower half 12 at 
the sliding position of the tape reel locking member 22, whereby the 
engaging nails 27 of the tape reel locking member 22 can be positively 
engaged with the gear portions 21 of the tape reels 13. 
The thus constructed tape reel locking member 22 can prevent, upon non-use 
of the tape cassette, the tape reels 13 from being rotated inadvertently 
as follows. 
Upon use of the tape cassette, as shown in FIG. 7, a lock release pin (not 
shown) provided on the cassette loading mechanism of, for example, a video 
camera enters this cassette housing 10 through an entrance 32 (see FIG. 
10) to bias the tape reel locking member 22 against the spring force of 
the spring 23, allowing the tape reels 13 to rotate. At that time, the 
engaging members 26 of the tape reel locking member 22 are displaced by 
stoppers 31 formed on the top portions of the guide walls 24 such that 
they approach each other. 
In the unloading operation for unloading the tape cassette from the 
cassette loading mechanism or the like from this condition, the tape reel 
locking member 22 thus spring-biased by the lock release pin (not shown) 
is released. 
When the tape reel locking member 22 is released from its biased state by 
the lock release pin, the tape reel locking member 22 is slidably moved 
between the guide walls 24 in the locking direction of the tape reels 13 
by the spring-biasing force of the spring 23. 
At that time, as shown in FIG. 8, while the tape reel locking member 22 is 
being slid, the extending operation member 29 comes in contact with the 
curved portions 26a of the engaging members 26 coupled to the top portion 
of the tape reel locking member 22 and then advances between the engaging 
members 26 to extend the engaging members 26, thus causing the engaging 
nails 27 formed on the top portions of the engaging members 26 to be 
engaged with the gear portions 21 of the tape reels 13, respectively. 
When the tape reel locking member 22 is further slid to the position of the 
stoppers 31 of the guide walls 24 under the condition that the engaging 
members 26 are engaged with the gear portions 21 of the tape reels 13, the 
engagement between the engaging members 26 and the gear portions 21 
slightly rotates the tape reels 13 in the direction in which the magnetic 
tape T is wound. Then, the reel locking operation is completed at the 
position shown in FIG. 9. The tape reels 13 are rotated in the magnetic 
tape rewinding direction, thus removing the slackening of the magnetic 
tape T. 
Specifically, according to the present invention, during the process where 
the tape reel locking member 22 is moved from the lock releasing state 
shown in FIG. 7 and the locking completion state shown in FIG. 9, the tape 
reel locking operation is carried out in former and latter steps. That is, 
in the former step, as shown in FIG. 8, the engaging members 26 come in 
contact with the extending operation member 29 to extend the engaging 
members 26, thus allowing the engaging nails 27 to be engaged with the 
gear portions 21 of the tape reels 13. In the latter step, the engaging 
members 26 rotate the tape reels 13 in the tape slack absorbing directions 
x. 
According to the above-mentioned tape reel locking member 22, while 
removing the slackening of the magnetic tape T, the tape reels 13 can be 
prevented from being rotated unintentionally upon non-use. Since the 
slackening of the magnetic tape T can be removed in the locking operation 
of the tape reels 13 as described above, when the tape cassette is 
unloaded from the cassette loading mechanism of the video camera or the 
like, the front lid 15 and the lid members (not shown) can be prevented 
from biting the magnetic tape T. Also, upon loading the tape cassette, a 
so-called tape jamming and the like can be prevented. 
Further, in the tape reel locking operation, the engaging members 26 for 
avoiding the inadvertent rotation of the tape reels 13 can be prevented 
from being displaced at their intermediate portions so that the top 
portions of the engaging members 26 can be prevented from being swung, 
thus enabling the engaging nails 27 to be positively engaged with the gear 
portions 21 of the tape reels 13. At the same time, the tape reels 13 can 
be positively rotated in the tape slackening absorbing directions x shown 
in FIG. 8. Even after the tape reels 13 are rotated as described above, 
the above-mentioned engagement between the engaging nails 27 and the gear 
portions 21 can be maintained positively by a sufficient pushing force. 
Furthermore, the above engaging members 26 are not provided with the hinge 
portions at their intermediate portions so that even when the engaging 
members 26 are left for a long period of time under the tape reel lock 
released condition or the like, the engaging members 26 can be prevented 
from being deformed. 
While the embodiment of the present invention is described as above, the 
present invention is not limited to the above embodiment but can take 
various modifications thereof on the basis of the technical idea of the 
present invention. As, for example, shown in FIG. 11, ribs 37 are formed 
on the curved portions of engaging members 36 of a tape reel locking 
member 35 thereby to reinforce the engaging members 36 such that they can 
be prevented from being displaced at their curved portions. 
On the other hand, as shown in FIG. 12, engaging members 41 of a reel 
locking member 40 are formed thick from their curved portions 42 to their 
engaging nails 43 so as not to be displaced, while the engaging members 41 
are formed thin from their curved portions 42 to their hinge portions 
formed on the base ends thereof so that the engaging members 41 function 
as a limiter which limits the rotation of the tape reels 13. 
According to the present invention, as set forth above, after the tape 
reels are slightly rotated in the slackening absorbing direction of the 
magnetic tape by the tape reel locking member, the tape reels can be 
locked. Therefore, the tape reels can be locked positively without 
slackening the magnetic tape. Further, when the tape reels are locked by 
the tape reel locking member, the engaging members to be engaged with the 
tape reels can be prevented from being displaced at their intermediate 
portions so that the gear portions of the tape reels and the engaging 
nails can be engaged with each other by a sufficient pushing force. 
Accordingly, when the tape reels are rotated in the tape slackening 
absorbing directions by the engaging nails, the engaging nails can be 
prevented from being disengaged from the gear portions of the tape reels. 
Therefore, according to the present invention, the tape slack can be 
avoided and the tape reels can be positively prevented from being rotated 
unintentionally upon non-use. 
It should be understood that the above description is presented by way of 
example on the preferred embodiments of the invention and it will be 
apparent that many modifications and variations thereof could be effected 
by one with ordinary skill in the art without departing from the spirit 
and scope of the novel concepts of the invention so that the scope of the 
invention should be determined only by the appended claims.