Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Cartridge system
Reexamination Certificate
1999-11-12
2002-09-10
Rivera, William A. (Department: 3653)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Cartridge system
C242S338300, C360S132000
Reexamination Certificate
active
06446896
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a tape cassette for use in a magnetic recording and reproducing device such as a video tape recorder (VTR) and more particularly to a tape cassette for use as a video tape cassette such as an 8 mm video tape cassette and a digital video cassette (DVC) which has a tape-like medium received in a case thereof via tape reels and incorporates therein a reel brake mechanism for regulating the rotation of the tape reels when the tape cassette is not in use.
Conventionally, in a tape cassette in which a pair of tape reels around which a tape-like medium is wound are rotatably installed in a case thereof, a brake mechanism for stopping the rotation of the tape reels when the tape cassette is not in use is widely used which is constructed such that a brake member is biased against teeth provided on outer circumferences of flanges of the tape reels by means of a resilient member such as a torsional coil spring and a leaf spring, and when this tape cassette so constructed is mounted in the recording and reproducing device, a brake releasing member of the recording and reproducing device is brought into abutment with the brake member and moves the brake member against the resilient force of the spring so as to disengage the brake member from the tape reels to thereby allow the tape reels to rotate (Japanese Unexamined Patent Publication Nos. 6-318383 and 10-112158, and Japanese Unexamined Utility Model Publication Nos. 3-106587 and 58-173073).
FIGS. 31A and 31B
are plan views showing one example of a conventional reel brake for a tape cassette,
FIG. 31A
showing a state in which the reel brake is in normal use, and
FIG. 31B
showing a state in which pawls are deployed. Arms
826
are provided on left and right sides of a main body
821
of the reel brake
820
in such a manner as to outwardly protrude therefrom. This arm
826
and the pawl
822
are connected to each other at a thin hinge portion
824
. The pawl
822
comprises a distal end portion
822
a,
a guided portion
822
b
and a root portion
822
c
which are integrally formed. The pawl
822
is formed so as to rotate about the hinge portion
824
as a fulcrum, and they are so constructed as to allow the pawl
822
to rotate appropriately when the distal end portion
822
a
of the pawl
822
is brought into engagement with teeth formed in a tape reel to thereby provide a smooth engagement between the pawl
822
and the teeth.
The reel brake
820
is disposed in the tape cassette in a state as shown in
FIG. 31A
, in which the guided portion
822
b
engages a guide groove formed on a case main body side.
In the aforesaid conventional reel brake for a tape cassette, however, a number of reel brakes are received as one of parts for a tape cassette in a box or the like for transportation after they are formed until they are incorporated into a tape cassette, and in assembling, they are put in volume in a part feeder or the like of an automatic assembling machine. During these stages, reel brakes
820
get entangled in each other, and as shown in
FIG. 31B
, the pawl
822
is unnecessarily rotated (excessive rotation), and moreover this repeatedly happens, since the thickness of the hinge portion
824
is extremely thin (e.g., on the order of 0.13 mm), there is caused a cut (crack) in the hinge portion
824
and there may be even a case where the hinge portion
824
is cut thereat.
In addition, when the reel brake
820
is used in a state in which there is cause to cut in the hinge portion
824
, the hinge portion
824
is cut while in use, thereby causing a problem that the reel brake
820
cannot fulfill the function to lock the tape reels.
Furthermore, although the strength of the hinge portion
824
is improved if a resin material (for instance, polypropylene) is used which has a hinge effect strong enough to deal with repeated bending, since materials have to be selected while taking into consideration the moldability and slidability of the reel brake
820
, there has been a certain limit to increasing the strength of the hinge portion
824
.
FIGS. 32A and 32B
shows an example of another conventional reel brake, in which
FIG. 32A
is a plan view showing a state in which a reel brake
908
mounted in a lower case
902
engages teeth
903
d
formed in a tape reel
903
and
FIG. 32B
is a sectional view corresponding to a plane A—A of FIG.
32
A and showing a state in which an upper case
901
is mounted on the lower case
902
.
The teeth
903
d
are formed in an outer circumference of the tape reel
903
. In addition, in
FIG. 32A
, the reel brake
908
is disposed slidably in vertical directions. Pawls
908
c
are provided on left and right sides of a main body
908
a
of the reel brake
908
, which pawls
908
c
are adapted to freely rotate via thinned hinge portions
908
b.
The reel brake
908
is biased toward the tape reel
903
side by virtue of a spring force of a spring (not shown) when the tape cassette is not in use, and the tape reel
903
is locked when the pawl
908
c
of the reel brake
908
enters between the teeth
903
d
formed in the tape reel
903
.
In addition, when the tape cassette is in use, the reel brake
908
is slid in a direction in which it moves away from the tape reel
903
against the biasing force of the spring, whereby the engagement between the reel brake
908
and the tape reel
903
is released.
Furthermore, a position regulating portion
902
b,
for regulating the position of the reel brake
908
, is provided in the lower case
902
in such a manner as to be erect therefrom. A front of the main body
908
a
of the reel brake
908
and a position regulating wall
902
b
are constructed so as to be brought into abutment with each other at a position where a distal end of the pawl
908
c
of the reel brake
908
engages the teeth
903
d
of the reel brake
903
, whereby the reel brake
908
is prevented from sliding further toward the tape reel
903
side from this regulated position.
In the conventional tape cassette, however, since a gate portion
908
f
exists in the front of the main body
908
a
of the reel brake
908
, there is no problem caused when the gate portion
908
f
is flat, but as shown in
FIGS. 32A and 32B
, in a case where there remains a projection (the remains of the gate) at the gate portion
908
f,
there is caused a problem that the front of the main body
908
a
does not abut with the position regulating wall
902
b,
but only the gate portion
908
a
abuts therewith, and there may be caused a risk in which the reel brake
908
is not allowed to slide to an original engagement position where the reel brake
908
engages the teeth
903
d
of the tape reel
903
.
Even if the distal end of the pawl
908
c
of the reel brake
908
engages the teeth
903
d
of the tape reel
903
, the engagement therebetween becomes insufficient, and this causes a problem that the designed braking function cannot be securely performed.
Here, to deal with the aforesaid problem, first of all, it is considered to finish the gate after the reel brake
908
is formed such as by cutting a projection with a pair of nippers or grinding away the same with a file. However, a processing like this involves a problem of increased costs.
Secondly, it is considered to dispose the gate of the reel brake
908
at a position other than in the front of the main body
908
a
of the reel brake
908
. However, upper and lower surfaces of the main body
908
a
of the reel brake
908
are brought into abutment with internal walls of the upper case
901
and the lower case
902
and constitute a sliding surface for the reel brake
908
, and therefore if the gate portion
908
f is provided in these surfaces, there may be caused a risk of a sliding failure, which is not preferable.
In addition, generally, the back of the main body
908
a
is a surface which is adapted to be brought into abutment with a spring for biasing the reel brake
908
and therefore, the configuration thereof becomes complicated, and it is not preferable to provide the gate portion
Hashizume Kenji
Kaneda Hiroshi
Momoi Akio
Okamura Masatoshi
Shima Motohiko
Rivera William A.
TDK Corporation
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