Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
2000-08-17
2002-06-18
Davis, David (Department: 2652)
Dynamic magnetic information storage or retrieval
Record medium
In container
Reexamination Certificate
active
06407887
ABSTRACT:
TECHNICAL FIELD
This invention relates to a magnetic tape cassette, and more particularly to the lock mechanism of the lid which, when the magnetic tape cassette is loaded in a device such as a VTR (video tape recorder), is opened to pull out the magnetic tape, and is closed when the cassette is not in use.
BACKGROUND ART
As is well known in the art, a variety of magnetic tape cassettes are used for video devices such as video decks. Among those cassettes, a relatively small one is for instance a digital video cassette (DVC).
Now, an example of a magnetic tape cassette known as a DVC will be described with reference to
FIGS. 3 and 4
. First, the construction of a conventional magnetic tape cassette will be described with reference to FIG.
3
. In a lower half case (hereinafter referred to as “a lower half”, when applicable)
31
, a pair of reels
32
a
and
32
b
are rotatably arranged, and a magnetic tape (not shown) is wound on those reels
32
a
and
32
b.
The magnetic tape is guided by right and left tape guides
33
a
and
33
b
which are provided at the front end of the cassette, thus passing through an opening
34
formed in the front end of the lower half
31
. The peripheries of the reels
32
a
and
32
b
(the peripheries of the lower flanges) have teeth
35
a
and
35
b,
respectively.
On the other hand, in order to eliminate the difficulty that, when the magnetic tape cassette is not loaded in the video deck (not shown); i.e., when the cassette is carried or stored, the magnetic tape is loosen; in a space at the rear side of the cassette which is formed between the reels
32
a
and
32
b,
a brake member
38
and a compression spring (or a brake spring)
39
are arranged. The brake member
38
has locking pawls
37
a
and
37
b
forming a lock device which is to lock the rotation of the reels
32
a
and
32
b.
The compression spring
39
urges the brake member
38
.
On the other hand, the upper half case (hereinafter referred to as “an upper half”, when applicable)
40
has an outer lid
41
to cover the front opening of the lower half
31
, an upper lid
42
, and an inner lid
43
. Those lids are provided in such a manner that they are freely opened and closed.
Lid lock pawls
45
are protruded from the inner surfaces of both side boards
44
of the outer lid
41
. And frame-shaped accommodating sections
51
are provided inside of the right and left side boards
46
. The frame-shaped accommodating sections
51
have functions for mounting swingably lid locks
47
which are locked to the lid lock pawls
45
of the outer lid
41
. Behind each of the accommodating sections
51
, a spring
48
is provided which is to urge the lid lock
47
to be locked. The provision of the spring
48
is achieved by coupling the ring which is formed at the end of the spring
48
to a locking pin
52
.
The accommodating sections
51
are symmetrical in structure and the lid locks
47
are also symmetrical in its accommodation state, and therefore the left half of
FIG. 3
shows a state of explosion, while the right half shows the state of accommodation. In
FIG. 3
, for simplification in description, those other than essential components are not designated by reference characters, and are not described.
Now, the lock arrangement and function to freely open and close the outer lid
41
will be described with reference to FIG.
4
.
FIG. 4
is a side view of the front part of the magnetic tape cassette; more specifically,
FIG. 4
is a side view, with parts cut away, to clearly show the structure and function of the lid lock pawl
45
, the lid lock
47
, and parts concerning the latter
45
and
47
.
As shown in
FIG. 3
, the position of formation of the lid lock pawl is shown on the inner surface of the side board
44
forming the outer lid
41
. Its configuration is such that, as shown in FIG.
4
, it is vertically long, and its lower end portion is tapered. On the other hand, a pair of shafts
53
are provided on both sides of the lid lock
47
. The shafts
53
are placed on recess-shaped shaft receiving sections
54
which are formed in both walls of the accommodating section
51
, so that the lid lock
47
is swingably supported. The top of the lid lock
47
has a locking groove
55
, to which one end of the spring
49
is locked. In the locking groove
55
, a protrusion
55
a
is formed on the right side of the shaft
53
. As the spring
48
is engaged with the protrusion
55
a,
the lid lock
47
is kept urged clockwise.
In the above-described magnetic tape cassette
30
, when it is not loaded in a video deck or the like, the lid lock
47
is urged clockwise. Hence, the lid lock pawl
45
is locked by a hook
47
a,
so that the outer lid
41
integral with the lid lock pawl
45
is not opened.
On the other hand, when the magnetic tape cassette
30
is loaded in a video deck of the like, a reacting section
47
b
is urged in the direction of the arrow A, so that the whole lid lock
47
is swung counterclockwise about the shaft
53
. That is, the whole lid lock
47
is swung from the position indicated by the solid line to the position indicated by the phantom line, so that the locking of the lid lock pawl
45
and the hook
47
a
of the lid lock
47
is released.
As a result, the outer lid
41
is swung clockwise about the fulcrum pin
63
, thus swinging while pushing the upper lid
42
thereby to open the front
34
of the magnetic tape cassette
30
. Owing to the urging force of the outer lid
41
, the upper lid
42
is moved backwardly while being guided by the guide grooves
54
formed in both side surfaces, so that the magnetic tape can be pulled out towards the front
34
.
The above-described magnetic tape cassette
30
has a variety of problems as described below: That is, since the lower portion of the lid lock pawl
45
is tapered, for instance when the magnetic tape cassette is dropped, the lid lock pawl may be deformed if a shock is applied to the end portion which is abutted against the hook
47
a
of the lid lock
47
. For instance, owing to the impact force attributing to the dropping of the magnetic tape cassette, the end of the lick lock pawl
45
is strongly abutted against the side surface of the lid lock, thus being deformed, collapsed or rolled up. Owing to this deformation, the lid lock pawl
45
is pushed upwardly, so that the lid
41
is pushed upwardly as a whole, thus playing with respect to the hook
47
a.
That is, the lid is not satisfactorily closed.
Sometimes, the locking force is decreased, so that the lid is unintentionally opened. Owing to the impact attributing to the dropping of the magnetic tape cassette, the magnetic tape is slackened so that its part comes out of the lid
41
thus opened. In this case, when the lid
41
is closed, the magnetic tape is bitten thereby. This trouble is serious.
Japanese Utility Model Unexamined Publication No. Sho. 62-229583 has disclosed an example of a tape cassette in which the lid lock is engaged with the side surface of the lid lock pawl, thereby to prevent the lid from being unintentionally opened, and, in order that the end of the lid lock pawl is suitably disengaged from the lid lock when unlocked, the engaging section of the lid lock is inclined at a suitable angle, and a gap is formed between the lid lock pawl and the lid lock.
However, the effect of the tape cassette disclosed by the Japanese Utility Model Unexamined Publication No. Sho. 62-229583 cannot be obtained unless the lid pawl is formed with an accurate angle of inclination. On the other hand, the lid lock of a DVC or the like is a small component. Hence, in the case where the technical concept of the Japanese Utility Model Unexamined Publication No. Sho. 62-229583 is applied to the lid lock of a DVC or the like, its dimensions must be controlled with extremely high accuracy when molded.
DISCLOSURE OF THE INVENTION
In view of the foregoing, an object of the invention is to provide a magnetic tape cassette which is advantageous as follows: Even when the magnetic tape cassette is dropped, or an impact is applied onto it, the lid is prevente
Asano Katsuki
Ashikawa Teruo
Davis David
Fuji Photo Film Co. , Ltd.
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