Advancing material of indeterminate length – By orbitally traveling material-engaging surface – Including details of roll or mount
Reexamination Certificate
2002-05-31
2004-06-29
Matecki, Kathy (Department: 3654)
Advancing material of indeterminate length
By orbitally traveling material-engaging surface
Including details of roll or mount
C226S180000, C226S190000, C384S192000, C360S095000
Reexamination Certificate
active
06755333
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tape guide post mechanism for use in a magnetic recording/reproducing apparatus, such as a videotape recorder (VTR).
2. Description of the Related Art
In recent years, there has been a growing demand for decreases in size and price of magnetic recording/reproduction apparatus, such as VTRs, camcorders, etc.
Hereinafter, a tape guide post mechanism for use in a conventional magnetic recording/reproducing apparatus is described.
FIG. 6
is a plan view of a magnetic recording/reproducing apparatus which uses a conventional tape guide post mechanism.
FIG. 6
shows that a tape
2
has been pulled out from a cassette
1
by tape guide posts
8
,
9
,
10
, and
13
, and looped around a rotatable head cylinder
6
. In this state, recording/reproduction of data or information to/from the tape
2
can be performed. In
FIG. 6
, some parts are omitted (i.e., not shown) for clarity of illustration.
As shown in
FIG. 6
, reference numeral
2
denotes a tape, which is wound around an S-reel
4
a
and a T-reel
5
a
stored in the cassette
1
. For clarity of illustration, the external shape of the cassette
1
is represented by a dashed line. Reference numeral
3
denotes a base of the magnetic recording/reproducing apparatus, on which the cassette
1
is mounted. Reference numeral
4
denotes an S-reel bed, which is rotatably and axially supported on the base
3
. The S-reel bed
4
is engaged, and rotates integrally, with the S-reel
4
a.
Reference numeral
5
denotes a T-reel bed, which is rotatably and axially supported on the base
3
. The T-reel bed
5
is engaged, and rotates integrally, with the T-reel
5
a
. Reference numeral
15
denotes a tension arm (post arm). The tension arm
15
has: a tension post
8
, which is one of the tape guide posts, and which is one of the constituent elements of a tape running system; and a hole
15
a
. The base
3
has a tension arm shaft
14
, which is provided so as to penetrate through the hole
15
a
, so that the tension arm shaft
14
rotatably supports the tension arm
15
. Reference numeral
18
denotes a tension band, one end of which is supported by a shaft
15
b
formed in the tension arm
15
, and the other end which is fixed to the base
3
with a band fixture screw
19
. The intermediate portion of the tension band
18
is wound around a cylindrical portion
20
of the S-reel bed
4
. The tension arm
15
is urged by an urging spring
15
c
around the tension arm shaft
14
in a counterclockwise direction.
Reference numeral
6
denotes a rotatable head cylinder provided on the base
3
. The rotatable head cylinder
6
has a rotatable magnetic head, through which a signal is recorded in/reproduced from the tape
2
that is looped around the rotatable head cylinder
6
. Reference numeral
7
denotes a S1-post, which is one of the tape guide posts. Reference numeral
11
denotes a T2-post, which is one of the tape guide posts. The S1-post
7
and the T2-post
11
are fixed to the base
3
, and are constituent elements of the tape running system. Reference numeral
9
denotes a S2-post, which is one of the tape guide posts. Reference numeral
10
denotes a T1-post, which is one of the tape guide posts. The S2-post
9
and the T1-post
10
are constituent elements of the tape running system. Reference numeral
12
denotes a capstan shaft, and reference numeral
100
denotes a pinch roller. The tape
2
which is sandwiched by the capstan shaft
12
and the pinch roller
100
is driven in a forward/reverse direction by forward/reverse rotation of the capstan shaft
12
. Reference numeral
13
denotes a T3-post, which is one of the tape guide posts, and is a constituent element of the tape running system. The T3-post
13
is formed in a T3-arm
17
which is a post arm. The T3-arm
17
has a hole
17
a
. A T3-arm shaft
23
a
which is formed on the base
3
is provided so as to penetrate through the hole
17
a
, so that the T3-arm shaft
23
a
rotatably supports the T3-arm
17
.
FIG. 6
shows that the tape
2
has been pulled out of the cassette
1
by the tension post
8
, the S2-post
9
, the T1-post
10
, and the T3-post
13
.
The tape running system shown in
FIG. 6
is now described. The tape
2
pulled out from the S-reel
4
a
is first looped around the S1-post
7
on the base
3
, and then, looped around the tension post
8
and the S2-post
9
. Further, the tape
2
is looped around the rotatable head cylinder
6
, and around the T1-posts
10
and the T2-posts
11
. Thereafter, the tape
2
is looped around the capstan shaft
12
and the T3-post
13
. Thereafter, the tape
2
is wound around the T-reel
5
a.
Hereinafter, an operation of the tape guide post mechanism of the conventional magnetic recording/reproducing apparatus having the above described structure is described with reference to
FIGS. 7 through 9
.
FIG. 7
is a cross-sectional view showing the T3-arm
17
of the conventional tape guide post mechanism.
FIG. 8
is a cross-sectional view showing the state of the T3-arm
17
when a tape tension is applied to the T3-arm
17
.
FIG. 9
is a perspective view showing the details about engagement between the hole
17
a
of the T3-arm
17
and the T3-arm shaft
23
a.
In
FIG. 7
, the tape
2
is not looped around the T3-post
13
. The hole
17
a
of the T3-arm
17
is rotatably engaged with the T3-arm shaft
23
a
formed on the base
3
. The T3-arm
17
is prevented by a stoppage ring
21
from being upwardly disengaged from the T3-arm shaft
23
a
. Further, some space
22
is necessarily provided between the internal wall surface of the hole
17
a
and the external side surface of the T3-arm shaft
23
a
such that the T3-arm
17
is rotatable around the T3-arm shaft
23
a.
When the tape
2
is looped around the T3-post
13
so as to have a predetermined contact area therebetween which corresponds to a predetermined angular distance around the T3-post
13
so that the tape
2
can run, tape tension Ta is applied to the T3-post
13
as shown in FIG.
8
. Due to tape tension Ta, a rotation moment is caused in the T3-arm
17
and the T3-post
13
in the direction of arrow M. Accordingly, the T3-arm
17
slightly rotates in the direction of arrow M as shown in FIG.
8
. As a result, the internal wall surface of the hole
17
a
of the T3-arm
17
is in contact with the external side surface of the T3-arm shaft
23
a
at an upper contact point
30
and a lower contact point
31
as shown in
FIGS. 8 and 9
.
FIG. 9
shows the slanted T3-arm
17
only in the vicinity of the T3-arm shaft
23
a
. As seen from
FIG. 9
, a hole center line
33
between the center of the upper opening of the hole
17
a
of the T3-arm
17
(“upper hole center
32
a
”) and the center of the lower opening of the hole
17
a
of the T3-arm
17
(“lower hole center
32
b
”) is slanted with respect to the longitudinal axis of the T3-arm shaft
23
a.
However, the above conventional structure involves some problems as described below with reference to
FIGS. 8 and 9
.
Since the T3-post
13
is a constituent element of the tape running system, the slant of the T3-post
13
must be accurately determined. However, due to small, external disturbing factors, such as a variation of tape tension Ta, a variation of friction force generated between the T3-post
13
and the tape
2
, etc., the position of the upper contact point
30
unstably shifts in a direction indicated by arrow B of
FIG. 9
, and the position of the lower contact point
31
unstably shifts along a direction indicated by arrow C of FIG.
9
. That is, the slant of the hole center line
33
with respect to the axis of the T3-arm shaft
23
a
is varied, and the amount and direction of slant of the T3-post
13
are unstable.
Further, in the case where tape tension Ta is not sufficiently large with respect to the weights of the T3-arm
17
and the T3-post
13
, upper and lower contact points are sometimes formed at positions opposite to the upper contact point
30
and the lower contact point
31
, respectively, with
Hirabayashi Koichiro
Konishi Akio
Nagasaki Eiji
Kim Sang K
Matecki Kathy
Matsushita Electric - Industrial Co., Ltd.
Renner , Otto, Boisselle & Sklar, LLP
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