Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Cartridge system
Reexamination Certificate
2001-05-25
2004-04-13
Nguyen, John Q. (Department: 3653)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Cartridge system
C360S132000
Reexamination Certificate
active
06719232
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a magnetic tape cassette such as a digital video cassette (DVC) or the like.
BACKGROUND OF THE INVENTION
Generally, in an audio apparatus, a video apparatus and the like, there are in many cases used magnetic tape cassettes of a structure that a magnetic tape wound around a pair of tape reels is held inside a cassette case so as to run for conducting recording and reproducing.
FIG. 12
is an exploded perspective view of the DVC which is one example of the magnetic tape cassette. The magnetic tape cassette
50
comprises an upper cassette half
2
and a lower cassette half
3
each of which has a flat plate and peripheral walls. These upper and lower cassette halves
2
,
3
are assembled and fastened by means of a plurality of screws. A pair of tape reels
1
which are formed by welding their upper flanges with their lower flanges are rotatably supported in the lower cassette half
3
in a state where a magnetic tape
47
is wound around the tape reels
1
.
There are provided tape guides
14
at both sides of an opening
5
which is formed at a front end side (a lower side in the drawing) of the lower cassette half
3
. Each of the tape guides
14
is adapted to guide the magnetic tape
47
which is fed from one of the tape reels
1
and taken up by the other tape reel and to pass the magnetic tape
47
at a determined position corresponding to the opening
5
.
A tape reel locking member
16
having a tape reel locking arm
15
is assembled to a rear end side (an upper side in the drawing) of the lower cassette half
3
. The tape reel locking member
16
is biased by means of a compression coil spring
17
so as to engage the tape reel locking arm
15
with an engaging tooth which is formed at an outer circumference of the lower flange of each of the tape reels
1
thereby to block an accidental rotation of the tape reel
1
. A slackened winding of the magnetic tape
47
can be prevented with this arrangement.
To the flat plate
4
of the upper cassette half
2
are fitted reel pressing leaf springs
48
for the respective tape reels
1
. Each of the reel pressing leaf springs
48
is supported by the upper cassette half
2
in a cantilever manner so as to push the corresponding tape reel
1
toward the lower cassette half
3
. Further, the flat plate
4
of the upper cassette half
2
is provided with an opening which extends in a transverse direction of the flat plate
4
at one side of the flat plate
4
in its longitudinal direction (a right hand in the drawing) so that an amount of winding of the magnetic tape
47
on the tape reels
1
can be confirmed. A transparent window member
49
is fitted so as to close the opening.
To a front end side of the upper cassette half
2
are freely and openably fitted an outer lid
20
, a top lid
21
and an inner lid
22
for covering a front and a back faces of the magnetic tape
47
which is stretched between a pair of the tape guides
14
in the lower cassette half
3
, in order to obtain such a dust proofing property as durable for an outdoor use.
FIG. 13
shows one of the tape guides
14
which are provided in the lower cassette half
3
and shown in FIG.
12
. Generally, the tape guide is uprightly provided on the flat plate of the lower cassette half. In this case, a hollow, that is, cylindrically formed tape guide
14
is integrally formed on the flat plate
10
of the lower cassette half
3
. The tape guide
14
includes a curved portion
30
with which the magnetic tape
47
slidably contacts, and flat portions
31
a
,
31
b
at a rear end side (an upper side in the drawing) and at an inner side (a left hand in the drawing) of the tape guide respectively with which the magnetic tape
47
does not contact. In this case, the tape guide
14
is formed in such a manner that a thickness of the tape guide
14
is substantially constant in a circumferential direction, and therefore, the curved portion
30
and the flat portions
31
a
,
31
b
are substantially equal to each other in thickness.
When the lower cassette half
3
is formed by molding, a molten resin introduced into a mold fills at first a cavity for the flat plate
10
. Then, the molten resin flows into cavities for the tape guides
14
connected to the cavity for the flat plate
10
and into cavities for other members.
There has been sometimes formed a weld line (hereinafter referred to as “a weld”) W on a surface of the curved portion
30
of the tape guide
14
as shown in
FIG. 14
, when the lower cassette half
3
of the above described magnetic tape cassette
50
is molded. In addition, a pock v of an air bubble which is generated when the air bubble is discharged has been also formed in some cases on the surface of the curved portion
30
. There is a fear that such a weld W or an air bubble pock v may damage the magnetic tape if they are formed on the surface of the curved portion
30
with which the magnetic tape slidably contacts.
The term “weld” means herein a thin line which is formed at a portion where two or more streams of the molten resin join, and the term “air bubble” means a hollow spot which is formed inside a molded article.
A first object of the invention is to provide a magnetic tape cassette which is free from molding defects on the surface of the curved portion of the tape guide with which the magnetic tape slidably contacts.
FIG. 15
shows a manner of placing the window member
49
on the flat plate
4
so as to close the opening formed in the flat plate
4
, when the window member
49
shown in
FIG. 12
is welded to the flat plate
4
of the upper cassette half
2
. As shown in
FIG. 15
, this work is generally conducted by hand.
An inner face (an upper face in the drawing) of the flat plate
4
of the upper cassette half
2
is formed at a peripheral part of the opening with a stepped flat face
35
a
(hereinafter referred to as “a window supporting face”) which is recessed from other parts of the inner face of the flat plate. The window supporting face
35
a
supports the peripheral edge of the window member
49
, when the window member
49
is placed on the flat plate
4
. A side face
35
b
between the inner face of the flat plate
4
and the window supporting face
35
a
is formed in a tapered shape which serves as an introducing face for guiding the window member
49
to the window supporting face
35
a.
FIG. 16
shows a sectional view taken along a line Y—Y in
FIG. 15
in a state where the window member
49
has been placed on the flat plate
4
. As shown in
FIG. 16
, a peripheral wall (a back end wall)
7
of the upper cassette half
2
is provided at its outer face with a recess
7
a
to which a label is to be attached. A peripheral edge of the window member
49
is arranged close to an inner face of a base portion of the peripheral wall
7
.
A part of an outer face (a lower face in the drawing) of the window member
49
which is supported by the window supporting face
35
a
is in a form of a stepped flat face
49
a
(hereinafter referred to as “a supported face”) which is recessed from other parts of the outer face of the window member. The supported face
49
a
is projectingly provided with a welded rib
49
b
in a shape of a triangle in section, which is adapted to abut against the window supporting face
35
a
of the flat plate
4
when the window member
49
is placed on the flat plate
4
.
FIG. 17
shows another upper cassette half
52
which has been conventionally used. The flat plate
4
of the upper cassette half
52
, similarly to the upper cassette half
2
shown in
FIG. 16
, has the window supporting face
35
a
, and the side face
35
b
connecting the inner face of the flat plate to the window supporting face
35
a
is formed in a tapered face. A positioning rib
45
having a side face which is vertical with respect to the inner face of the flat plate is formed at the inner face of the base portion of the peripheral wall
7
. In such an upper cassette half
52
, the window member
49
can be accurately positioned on the flat plate
4
without affecting its mountabil
Ashikawa Teruo
Hiraguchi Kazuo
Naito Hiroyuki
Onmori Shozo
Fuji Photo Film Co. , Ltd.
Nguyen John Q.
Sughrue & Mion, PLLC
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