Note: Descriptions are shown in the official language in which they were submitted.
1303736
MAGNETIC TAPE CASSEl~E HOLD~
BACl~GROUND OF TEIE INVI~NTION
The present invention relates generally to a
recording and reproducing apparatus for a magnetic tape
cassette, such as a tape cassette especially adapted to
recording and reproducing pulse code modulated (PCM)
signals. More specifically, the invention relates to a
cassette holder in a magnetic tape cassette recording
and reproducing apparatus, in which the tape cassette is
provided with a tape protective closure covering a front
opening through which a magnetic tape is extracted and
accessed, and a locking mechanism for locking the
closure open when the cassette is in use and locking it
closed when not in use.
In recent years, various recording and
reproducing apparatus have been developed which convert
analog signals, such as audio signals and the like into
a digital signal, e.g. PCM signal, which is then
recorded on and reproduced from magnetic tape serving as
a recording medium. Some of these apparatus employ
rotary heads in order to achieve a relatively high
recording density. Recording and reproducing apparatus
specifically designed to record and reproduce PCM
signals and employing a rotary head will be referred to
as "PCM recorder" throughout the disclosure. A PCM
recorder, at first, pulls a loop of a magnetic tape out
through a front opening of the cassette and winds the
tape around a rotary drum accommodating the rotary head
and then the recording and reproducing is performed. In
such digital recording and reproducing systems, oily
deposits, such as fingerprints or the like, and/or dust
adhering to the ~ape surface may cause dropout of
reproduced signals.
Various approaches have been tried to protect
the magnetic recording medium. A magnetic tape
3~
R
1303736
- 2 -
cassette is known which has a closure lid for retractably
covering the front end opening of the cassette, through
which the tape is extracted for access by a rotary head.
This closure lid is held closed while the tape is not in
use and is moved to an open position when the cassette is
inserted into the PCM recorder. In this earlier approach,
a drawback may be encountered when the closure lid is
unintentionally or accidentally opened, exposing the tape
to oily fingerprints, dust and so forth while it is not in
use. A locking mechanism which can conveniently lock the
closure lid in its open and closed positions could resolve
this problem.
The magnetic tape cassette disclosed above also
has a sliding closure for closing a lower opening for
accepting entry of loading device and tape reel drive of
the recording and reproducin~ apparatus. The sliding
closure may also be movable between open and close
positions.
In order to enable a recording and reproducing
apparatus for aforementioned type of magnetic tape cassette
to handle, there has to be provided a mechanism or device
for releasing the locking mechanism from locking position
so that the closure may move between open and close
positions.
~UNMARY OF T~B INV~NTION
Therefore, it is an object of the present
invention to provide a mechanism or a device which can
effectively release locking of a locking mechanism of a
magnetic tape cassette and whereby enable closures of the
magnetic tape cassette to move between open and close
positions.
Another object of the present invention is to
provide a recording and reproducing apparatus for a
magnetic tape cassette, which is effectively prevent the
magnetic tape cassette from being inserted in wrong
13037~6
direction.
As will be appreciated, the lock release
mechanism of the present invention is applicable for a
maqnetic tape cassette of the such type type that is
provided with a pivotal closure lid pivotably secured to
opposite edges of a casing for movement between a closed
position, in which the front opening of the casing
through which a magnetic tape can be extracted for
loading onto a rotary head while not in use, and an open
position wherein the closure lid is pivoted away from
said opening to allow access to the tape while in use;
is also provided with a sliding closure member slidably
mounted on one face of the casing and cooperative with
the aforementioned pivotal closure lid, which sliding
closure member is held either in a closed position while
the pivotal closure lid is in its closed position to
cover a bottom spacing through which a device
constituting part of a tape handing mechanism may be
inserted, or an open position while the pivotal closure
lid is in its open position to allow the aforementioned
device of the tape handling mechanism to engage the
casing through the bottom spacing for extracting the
tape for loading onto the rotary head, and is retained
in its closed and open positions by means of a locking
member; and the locking member is associated with the
cassette casing and adapted to resiliently establish
locking engagement with the sliding closure member. The
locking member has an locking head engageable to the
sliding closure member but not protruding from the lower
surface of the sliding closure member.
In the preferred embodiment of the magnetic
tape cassette, the locking member comprises a resilien~
arm integrally extending from the bottom of the cassette
casing and a locking head formed integrally with the
free end of the resilient arm.
According to the present invention, a locking
~30;~736
releasing mechaism is provided in a cassette holder of
the recording and reproducing apparatus which comprises
' a projection means which is active for releasing locking
to allow movement the sliding closure member for
movement from closed position to the open position when
the magnetic tape cassette is correctly inserted
thereto. The lock releasing mechanism also include
means for inhibiting insertion of the magnetic tape
cassette thereto when the inserting direction of the
cassette is wrong direction.
~303736
According to a further aspect of the invention,
a magnetic tape cassette comprises a hollow casing formed
with an access opening therein, a tape transport means
including a pair of reel hubs rotatably mounted within the
casing in spaced-apart relationship with each other for
supporting a magnetic tape wound thereon, the tape
transport means defining a tape run including part of the
access opening, a brake means mounted within the casing and
movable between a braking position in which it prevents the
hubs from rotating and a releasing position in which it
allows the hubs to rotate, a lid means engageable with the
brake means and movable between a closed position in which
it covers the opening, thereby partially protecting the
tape, and an open position in which it partially uncovers
the opening, thereby exposing the tape for cooperation with
a recording and reproducing apparatus, the lid means, in
moving from the closed position to the open position
effecting movement of the brake means from the braking
position to the releasing position, and in moving from the
open position to the closed position effecting movement of
the brake means from the releasing position to the braking
position, mounting means mounting the lid means on the
casing so as to be mobile between the closed position and
the open position, a sliding shutter member slidable with
respect to the cassette casing and cooperating with the lid
means to fully cover and uncover the access opening, the
shutter member being movable between a first position
partially covering the access opening and a second position
partially uncovering the access opening, and a
spring-biased locking pin disposed within the cassette
casing and movable along its longitudinal axis, the locking
pin normally holding the shutter member in the first
position while the cassette is not in use, and allowing the
shutter Member to move to the second position when the
cassette is inserted into an associated recording and
reproducing apparatus.
736
-- 6 --
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be understood more
fully from the detailed description given herebelow and
from the accompanying drawings of the preferred embodiment
of the invention, which, however, should not be taken to
limit the invention to the specific embodiment illustrated
but are for explanation and understanding only.
In the drawings:
Fig. 1 is a perspective view of the preferred
embodiment of a magnetic tape cassette in accordance with
the present invention, in which a pivotal closure lid and
a sliding closure member are in their respective closed
positions;
Fig. 2 is a perspective view of the magnetic tape
cassette of Fig. 1, viewed from the lower side of the
cassette, in which the pivotal closure lid and the sliding
closure member are in their respec ive closed positions for
use of cassette, corresponding to the position illustrated
in Fig. 1:
Fig. 3 is a perspective view of the magnetic tape
cassette of Fig. 1, viewed from the lower side of the
cassette, in which the pivotal closure lid and the sliding
closure member are in their respective open position during
use of the cassette;
Fig. 4 is an exploded perspective view of the
magnetic tape cassette of Fig. l;
Fig. 5 is a perspective view from the above of
the upper section of the tape cassette of Fig. 1, the upper
section being shown upside down;
Fig. 6 is an enlarged section taken along line
VI - VI of Fig. 2:
Fig. 7 is an enlarged partial section taken along
line VII - VII of Fig. 2;
Fig. 8 is a plan view of the lower section of the
tape cassette shown in Fig. 4 with the edges of the lower
section partially cut away to show the mode of engagement
between a brake member and the lower section:
1303736
- 7 -
Fig. 9 is a partial plan view of a cassette
holder of the recording and reproducing apparatus of Fig.
10, as viewed along arrow IX of Fig. 10:
Fig. 10 is a partial section of a recording and
reproducing apparatus (PCM recorder) with a rotary head to
which the preferred embodiment of the magnetic tape
cassette according to the present invention is applied;
Fig. 11 is a diagrammatic elevation of the
magnetic tape cassette of Fig. 1 showing the pivotal
closure lid and the sliding closure member in their closed
positions while the cassette is not in use;
Figs. 1~, 13 and 14 are sections similar to Fig.
10, showing the process of insertion of the preferred
embodiment of a magnetic tape cassette into the cassette
holder; and
Fig. 15 is a diagrammatic elevation similar to
Fig. 11, but showing the pivotal closure lid and the
sliding closure member in their open positions while the
cassette is in use.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, particularly to
Figs. 1 to 4, the preferred embodiment of a magnetic tape
cassette according to the present invention generally
comprises a casing 1 including an upper section 2 and a
lower section 3 which are connected by threaded bolts (not
shown) in a per se well-known manner, to form a single
unit. A transparent window plate 2a is built into the
upper surface of the upper section 2. A pair of reel hubs
4a and 4b incorporated into the cassette casing 1 rotatably
engage a pair of reel shaft insertion apertures 5a and 5b.
The apertures 5a and 5b are formed in the lower section 3
at predetermined positions which establish a suitable
spacing between the reel hubs 4a and 4b. A magnetic tape
6 is wound around the reel hubs 4a and 4b.
A pivotal closure lid 8 is rotatably or pivotally
attached at the right and left side walls of the cassette
X
~30373~
-- 8 --
casing near the front end of the tape cassette. When the
pivotal closure lid 8 is pivoted away from the front
surface of the tape cassette, the magnetic tape 6 is
exposed. An essentially rectangular cut-out 3a is formed
in the front end of the lower section 3. When the magnetic
tape cassette is inserted into a PCM recorder which will be
briefly discussed later, a tape guide system or a device
constituting part of a tape retaining mechanism (not shown)
which pulls out some of the tape 6 for loading onto a
rotary head of the PCM recorder, is inserted into the
cut-out portion 3a. A sliding closure member 9 engages the
lower section 3 and covers and exposes the cut-out portion
3a as it slides back and forth.
While the tape cassette is not in use, the
pivotal closure lid 8 is located opposite a front opening
formed in the front surface of the casing l to cover the
latter. At the same time, the sliding closure 9 is in its
forwardly-shi*ted position in which it covers the cut-out
portion 3a of the lower section 3 and thus prevents the
tape guide system from reaching into the tape cassette for
the tape. The pivotal closure lid 8 can pivot away from
the front surface of the cassette to expose the magnetic
tape 6, and the sliding closure member 9 can move to the
rear to expose the cut-out portion 3a so that the tape
guide system can reach into the cut-out portion 3a to draw
some of the magnetic tape 6 out of the cassette casing for
loading onto a rotary drum for recording or playback.
Thereafter, when the recording or playback is over and the
tape cassette is returned to the stand-by state, the
pivotal closure lid and the sliding closure member are
returned to the aforementioned closed positions.
Throughout the rest of this document, the positions of the
pivotal closure lid 8 and the sliding closure 9 in which
they cover the front opening and the cut-out portion 3a
respectively will be referred to as "stand-by position" and
the position of the lid 8 and the closure 9 in which they
1303736
g
expose the front opening and the cut-out portion 3a will be
referred to as "use position".
The cassette casing 1 also has a pair of tape
guide columns 7a and 7b integrally formed to the left and
right sides of the front edge of the lower section 3, as
shown in Fig. 4. The magnetic tape 6 is stretched between
and around the tape guide columns 7a and 7b so as to follow
a predetermined tape run or path along the front edge of
the tape cassette and across the front opening over the
rotary head.
The essentially rectangular cut-out portion 3a of
the lower section 3 extends over a predetermined width so
as to expose the rear surface of the magnetic tape 6
stretched between the tape guides 7a and 7b. During
recording or reproduction, a device constituting part of
the tape handling system or the tape guide system projects
into the cut-out portion 3a and draws out a section of the
magnetic tape 6. The tape handling system is part of the
PCM recorder.
The pivotal closure lid 8 is elongated along the
major dimension of the front opening and has arms 8a, 8b
projecting from its opposite ends which pivotably attach
lid 8 to the front of the cassette casing 1 by means of
pivot shafts 8d. Thus, the pivotal closure lid 8 can be
pivoted to selectively cover and expose the front opening
of the cassette casing 1. The closure lid 8 also comprises
a plate 8c which is elongated in the direction of the
opening in the cassette casing 1 and covers the entire
length of the front of the cassette casing 1. When the
closure lid 8 is rotated to the closed position to cover
the front of the cassette casing 1, the arms 8a and 8b lie
flush with the contours of the upper section 2 as best
shown in Figs. 1 and 2. When the closure lid 8 is in this
position, the closure member 9 is held in its forward
position under the arms 8a and 8b as shown in Figs. 2 and
3 by means described later. The rotary shafts 8d (only one
of which is visible in Fig. 4) about which the lid 8 pivots
1303736
-- 10 --
are approximately centered on the inner surfaces of the
respective arms 8a, 8b. Cut-away portions 8e, 8f are
formed by cutting small grooves into the lower edge of the
plate 8c toward the left and right extremes of the cut-out
portion 3a of the lower section 3.
The sliding closure member 9 has a flattened
U-shaped configuration and is so mounted on the lower
section 3 of the cassette casing 1 that it can slide back
and forth parallel to the lower surface of the lower
cassette section 3. Apertures 9a and 9b respectively
corresponding to the reel shaft insertion apertures 5a and
5b are formed in the sliding closure member 9 in such
positions that after the sliding closure member 9 slides
all the way backwards to sxpose the cut-out portion 3a, the
apertures 9a and 9b are respectively aligned with the reel
shaft insertion apertures 5a and 5b.
Positioning holes lOa and lOb are formed through
the bottom of the lower section 3 directly under the tape
guide columns 7a and 7b respectively.
The sliding closure 9, as shown in Fig. 4
comprises a flat plate 9c which lies parallel to the lower
surface of the lower section 3 and side plates 9d, 9e along
the left and right sides of the flat plate 9c while lie
parallel to the outer surfaces of the left and right side
walls of the lower section 3. Flanges 9f and 9g are formed
by bending the upper ends of the side plates 9d, 9e
inwardly. The flanges 9f, 9g are restrained vertically but
not horizontally between the side walls of the upper and
lower sections 2, 3 after the casing 1 is assembled. After
assembly, a spring-engaging anchor 9h formed on the flat
plate 9c projects through a spring-accommodating slot 18 in
the lower section 3. The spring anchor 9h anchors one end
of a tension coil spring 27 designed to bias the closure
member 9 in the forward direction. The other end of the
tension coil spring 27 engages a spring-engaging column 19
disposed near ths cut-out 3a of the lower section 3, with
the result that the closure member 19 is biased forward
13037;~6
-- 11 --
toward a position in which it covers the cut-out portion
3a. This movement of the sliding closure 9 also moves the
apertures 9a, 9b out of register with the apertures 5a, 5b
so as to co~pletely enclose the tape 6.
Contact pieces 9i and 9j extend upwards
perpendicularly from the flat plate 9c at the front of the
plate at positions which correspond to the cut-away
portions 8e and 8f of the closure lid 8. The contact
pieces 9i and 9j enable the recording-reproducing apparatus
to slide the closure 9 to the rear in preparation for
opening the cassette 1 in a manner described below.
Fig. 4 shows the relative position of the closure
lid 8, the sliding closure 9, a reel brake member 11, which
is described below, the upper section 2 and the lower
section 3. Each of these components may be made of
synthetic resin, such as ABS resin. The lower section 3
comprises an essentially rectangular flat plate of in which
the reel shaft insertion apertures 5a and 5b are formed and
a frame including left and right side walls, a front
portion in which the tape guide columns 7a, b are formed
and a rear wall. Most of the side walls and the outer
surface of the flat plate of the lower section 3 are
recessed so that the sliding closure 9 lies flush with the
outer surface of the remainder of the side walls and floor
of the lower section 3.
The front ends of the left and right side walls
are stepped laterally inwards by the thickness of the arms
8a, 8b of the closure lid 8 to form support walls 12. The
tops of the support walls 12 are formed with indentations.
When the upper section 2 and lower section 3 are assembled
with the lower section 3, matching support walls 20 in the
upper section 2 abut the support walls 12 edge-to-edge.
The indentations then form apertures allowing pivotal
mounting of the rotary shafts 8d (only one of which is
visible in Fig. 4) of the closure lid 8. Rectangular
insertion apertures 13 are formed near the front, lower
corners of the support walls 12. Shields 14a, 14b and 14c
1303736
- 12 -
define the three walls of the cut-out portion 3a, whereby
the inside of the cassette casing 1 is shielded from the
cut-out portion 3a.
Stepped rests 16a (only one of which is visible
in Fig. 4) extend along the upper edges of the left and
right side walls of the lower section 3 and parallel
thereto. The depth of the stepped rests 16a is not as
great as the thickness of the arms 8a, 8b of the closure
lid 8. Guide grooves 16b extend along each of the side
wall of the lower section 3 parallel to each other and to
the stepped rests 16b. Similarly to the rests 16a, the
guide grooves 16b are not as deep as the ar~s 8a and 8b of
the closure lid 8 are thick.
As best shown in Fig. 6, the stepped rests 16a
receive the upper edges 9g of the sliding closure 9. Also,
the guide groove 16b slidably recei~es inwardly depressed
indentations 26 formed in the side plates 9d and 9e of the
sliding closure 9. Sliding engagement between the rests
16a and the edges 9g and between the guide grooves 16b and
the indentations 26 guides sliding movement of the sliding
closure 9 with respect to the cut-out portion 3a along the
side walls of the lower section.
Annular collar or flange portions 17a, 17b
encircle each of the reel shaft insertion apertures 5a, 5b.
In order to bias the sliding closure 9 toward the
forward closed position, the rectangular
spring-accommodating slot 18 formed in the bottom plate 3c
of the lower section 3 is centered between the reel shaft
insertion apertures 5a, 5b and extends with its major
dimension parallel to the front-to-rear direction. ~ The
spring-engaging column lg is positioned at the forward end
of the spring-accommodating slot 18. The tension spring 27
biasing the closure member 9 forwards is stretched between
the column 19 and the anchor projection 9h formed on the
closure member 9.
Figs. 4 and 5 show details of the upper section
2. The upper section 2 comprises an essentially
1303736
- 13 -
rectangular flat plate in which the transparent window
plate 2a is formed and a frame including left and right
side walls and a rear wall. The outer contours of the
upper section 2 match the outer contours of the lower
section 3 and the sliding closure 9.
Support walls 20 are formed so that the forward
ends of the left and right side walls are offset inwardly
by the thickness of the arms 8a and 8b of the closure lid
8, as are the support walls 12 of the lower section 3. The
support walls 20 and 12 define apertures as described above
when they are assembled edge-to-edge.
A shielding wall 14d (Fig. 5) is designed to mate
with the shielding wall 14c (Fig. 4). When the upper
section 2 and lower section 3 are coupled, the shielding
walls 14d and 14c abut each other, thereby separating the
inside of the cassette casing from the cut-out portion 3a.
Arcuate collars 21a, 21b, 21c and 21d are formed
in alignment with the annular collars 17a and 17b of the
lower section 3. The reel hubs 4a and 4b are rotatably
supported by the collars 21a, 21b and 21c, 21d of thc upper
section 2 and the annular collars 17a and 17b of the lower
section 3. The collars 21a, 21b, 21c and 21d are
approximately as thick as the portions of the reel brake
member 11 which contact the upper section 2, so that the
reel brake member 11 can not protrude beyond the collar
portions 2la, 2lb, 21c and 2ld. This prevents the reel
brake member 11 from damaging the magnetic tape 6.
A fixing boss 22 (Fig. 6) of U-shaped
configuration in cross-section is formed on the upper
section 2 opposite the spring-engaging column 19 of the
lower section 3. When the upper section 2 and lower
section 3 are connected, the spring-engaging column 19 is
received within the opening of the fixing boss 22, and
hence the end of the coil spring 26 engaging the
spring-engaging column 19 is retained by the end of the
fixing boss 22.
1303736
- 14 -
A knurled recess 23 is formed near the rearward end of
each of the right and left side walls to facilitate a
secure grip when the cassette is held in the hand.
V-shaped concave supports 24 are formed near the center of
the left and right side walls. When the tape cassette is
loaded in the recording and reproducing apparatus, the
concave supports 24 are engaged by support studs (not
shown) from both the right and the left.
As shown in Figs. 5 and 7, a hollow cylindrical
boss 2b extends downwards from the upper section 2. A
cylindrical locking pin 15 opposing the boss 2b can slide
into and out of it vertically. The locking pin 15 has a
lower locking head 15c at the end distal from the boss 2b.
A flange 15a is formed on the locking pin 15 between the
proximal end and the locking head 15c. The locking head
15c is connected integrally to the proximal end and the
flange 15a through a section 15b. The section 15b is
cylindrical and has a larger diameter than the proximal
end. The cylindrical section 15b extends through a
circular opening 3b through the lower section. The locking
head 15c engages either a circular first locking opening 9k
or a semi-circular second locking opening 9m, both formed
in the flat plate 9c of the sliding closure 9. When the
locking head 15c engages the first locking opening 9k, it
locks the sliding closure 9 in its closed position. On the
other hand, when the locking head 15c engages the second
locking opening gm, it locks the closure member 9 in its
open position.
The locking pin 15 can slide longitudinally into
and out of the boss 2b. A bias spring 15d is wound around
the proximal end of the locking pin 15. The upper end of
the bias spring 15d seats on the lower end of the boss 2b
and the lower end of the bias spring 15d seats on the
flange 15a. In other words, the flange 15a serves as a
spring seat for the spring 15d. At the same time, the
flange 15a serves to limit the downward travel of the
locking pin in response to the force of the spring 15d.
13()37~6
- 15 -
For this reason, the diameter of the flange 15a is larger
than the internal diameter of the opening 3b through the
lower section.
The spring 15d constantly biases the locking pin
15 downwards so that the locking head 15c protrudes out of
the lower surface of the lower section 3 through the
opening 3b. The locking pin 15 is normally held in its
locking position in which it restricts sliding movement of
the sliding closure 9.
As shown in Figs. 4 and 8, the reel brake member
11 comprises a slide guide plate lla which is elongated in
a direction parallel to the front opening of the casing and
to the lid 8 and lies along the inner surface of the upper
section 2. The member 11 also comprises L-shaped arms llb,
llc which respectively extend perpendicularly downward from
either end of the slide guide plate lla and then forward.
Brake pins lld and lle corresponding to the reel hubs 4a
and 4b respectively extend rearward from the slide guide
plate lla. Brake wheels are formed on the outer peripheral
portions of the reel hubs 4a and 4b opposite the brake pins
lld and lle.
A spring-engaging stud llf is provided at the
center of the slide guide plate lla, and operating tabs llg
and llh are formed on the extreme ends of the arms llb and
llc respectively. The center coil of a torsion spring 25
used to bias the reel brake member 11 towards its braking
position is fitted onto the spring-engaging stud llf. The
free ends of the spring 25 press against the rear of the
shield wall 14d (Fig. 5) of the upper section 2 so that the
brake pins lld, lle normally engage the brake wheels of the
reel hubs 4a and 4b (see Fig. 11), whereby the reel hubs 4a
and 4b are prevented from rotating.
The reel brake member 11 is so disposed within
the cassette 1 that the ends of the tabs llg, llh protrude
through the insertion apertures 13 of the lower section 3
outside of the support walls 12 to a predetermined extent.
When the closure lid 8 is pivoted upwards, the protruding
1303736
tabs llg, llh are engaged by the ends of the arms 8a and 8b
of the closure lid 8, and the reel brake member 11 is
pulled forward against the biasing force of the spring 25.
The brake pins lld, lle are thus disengaged from the brake
wheels of the reel hubs 4a and 4b, allowing the reel hubs
4a and 4b to rotate (see Fig. 15). It should be noted that
the closure lid 8 is driven upwards by actuating pins (not
shown) of the recording/playback system when the cassette
1 is fully deployed in the operating position. The
actuating pins provide the force needed to overcome the
force of the torsion spring 25.
Referring to Figs. 10 and 12 to 14, a pair of
locking levers 34 are built into a cassette holder 33 at
points opposite each of the cut-outs 8e and 8f in the
closure lid 8. Each of the locking levers 34 is pivotably
secured to the bottom of the cassette holder 33 for
rotation about a pivot. Each of the locking levers has a
first arm section 34L with a locking claw section 34N
extending upwards from the free end of the first arm
section. The locking levers 34 also have a second arm
section 34s extending opposite the first arm section 34L
with respect to the pivot. The first and second sections
34L and 34s extend oblique to each other in such a manner
that, when the first arm section 34L is parallel to the
bottom of the cassette holder 33, the second arm section
34s is at an angle of about 45 degrees relative to the
bottom of the cassette holder 33.
Although it is not clearly shown in the drawings,
the locking lever 34 is associated with a biasing means,
such as a torsion spring normally biasing the locking lever
counterclockwise as viewed in Fig. 10. Therefore, as will
be appreciated from Fig. 10, the first arm section 34L is
normally biased toward the bottom of the cassette holder 33
and the second arm section 34s is normally held away from
the bottom of the cassette holder as in Figs. 10, 12 and
13.
~303736
- 17 -
The locking claw section 34n opposes an opening
(not shown) through the bottom of the cassette holder 33.
In the position of the cassette holder 33 of Figs. 10, 12
and 13, the locking claw section 34n extends through the
opening into the internal space of the cassette holder.
The position of the locking claw when projecting into the
internal space 33a of the cassette holder 33 matches the
position of the front edge of the sliding closure 9 in its
rearwardly shifted or open position. The locking claw
section 34n thus restricts forward movement of the sliding
closure 9 after the cassette is inserted into the cassette
holder as far as the position shown in Fig. 12. A stopper
35 extends upwards from the floor of the cassette holder 33
near the opening for the locking claw 34n. The stopper 35
is designed to contact the front edge of the sliding
closure 9 after the locking engagement between the locking
claw 34n and the front edge of the closure member 9 is
released to ensure that the closure member 9 will not
abrupt shift forward and damage the recording and
reproducing mechanism inserted into the cut-out portion 3a
of the cassette. This function will be made clearer later.
The cassette holder 33 is also provided with a
retainer spring 36 protruding from the ceiling of the
cassette holder. The retainer spring 36 engages the upper
surface of the tape cassette casing to restrict movement of
the latter within the cassette holder.
In addition, a through opening 37 through the
floor of the cassette holder 33 allows the head 15c of the
locking pin 15 to extend therethrough.
Figs. 12 to 14 show the operation of the tape
cassette 1. When the cassette 1 is not in use (see Figs.
7 and 8), the front thereof is covered by the closure lid
8 and the sliding closure 9 is biased by the coil spring 27
to its forward position. In that case, the reel brake
member 11 is biased rearward by the spring 25 and hence the
brake pins lld, lle engage the brake wheels of the reel
hubs 4a and 4b so that the reel hubs 4a and 4b are locked
1303736
- 18 -
and cannot rotate. In addition, the reel shaft insertion
apertures 5a and 5b of the cassette casing 1 and the
corresponding apertures 9a and 9b in the sliding closure
member 9 are offset from each other and the cut-out portion
3a is covered by the sliding closure 9. The magnetic tape
6 is thus fully enclosed to prevent dust from entering
through the apertures 5a and 5b or the cut-out portion 3a
and depositing on the magnetic tape 6, and fingers and the
like from touching the magnetic tape 6. Furthermore, the
side plates 9d and 9e o~ the closure member 9 are directly
beneath the arms 8a and 8b, whereby the closure lid 8 is
prevented from rotating. As a result, when the cassette is
not in use, the closure lid 8 is prevented from being
opened unintentionally.
In use, the tape cassette is loaded into a
recording and reproducing apparatus 28. By inserting the
tape cassette into the internal space 33a of the cassette
holder 33, the head portion 15c of the locking pin 15
protruding through the hole 3b in the lower section 3 of
the cassette casing 1 comes into contact with the ~loor of
the cassette holder. At the same time, the locking claws
34n of the locking levers 34 of the cassette holder 33 of
the recording and reproducing apparatus 28 engage the
contact member 9i and 9j of the closure member 9 through
the cut-away portions 8e and 8f of the closure lid 8.
Then, as the tape cassette moves further forward into the
recording and reproducing apparatus 28, the sliding closure
9 is held stationary by the locking claws 34n of the
locking lever 34, while the cassette casing 1 moves against
the biasing fcrce of the coil spring 27.
When the cassette casing 1 is inserted into the
cassette holder 33, the locking pin 15 is driven upwards
out of the hole 9k to the position shown in phantom lines
in Fig. 7 by contact with the floor of the cassette holder
33. From this position, since the end of the head portion
15c is rounded, an upward biasing force is applied to the
locking pin by the edge of the opening 9k of the sliding
1303736
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closure 9 as the cassette casing 1 moves relative to the
sliding closure member 9. The upward biasing force applied
to the locking pin 15 overcomes the downward biasing force
applied by the spring 15d and moves the locking pin 15
upwards. Until the sliding closure 9 disengages from the
locking pin 15 to allow relative displacement of the
cassette casing 1 and the sliding closure 9. A spacer 35
supports the lower section 3 during insertion.
Thus the sliding closure 9 slides backwards
relative to the cassette casing 1, thus exposing the
cut-out 3a and the positioning apertures 10 and lOb (Fig.
9), and aligning the apertures 9a and 9b of the closure
member 9 with the reel shaft insertion apertures 5a and 5b
so that the reel shaft insertion apertures 5a and 5b are
opened.
After the cassette has been fully inserted into
the cassette holder 33, the locking pin 15 comes into
alignment with a hole 37 through the floor of holder 33 and
drops through the holes 9m and 37, thus locking the sliding
closure 9 and cassette casing 1 together again, as shown,
in Fig. 13. From this position, the cassette holder 33 is
ready to be lowered into the recording and reproducing
system 28 to the position shown in Fig. 14, which position
is specified by a spacer 29.
The closure lid 8 is then rotated upwards by the
lid actuating pins (not shown) of the recording and
reproducing apparatus to the position shown in Figs. 14 and
15. As the closure lid 8 pivots, the operating tabs llg,
llh of the reel brake member 11 are pressed forward by the
lower ends of the arms 8a, 8b, thus sliding the reel brake
member 11 forward against the biasing force of the spring
25. This disengages the brake pins lld and lle from the
brake wheels of the reel hubs 4a and 4b and releases the
reel hubs 4a, 4b so that they can rotate.
Positioning protrusions 30 and reel shafts 31 of
the recording and reproducing apparatus 28 are respectively
inserted into the positioning apertures lOa and lOb and the
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- 20 -
reel shaft insertion apertures 5a and 5b, the magnetic tape
6 is exposed at the front of the cassette casing 1, and the
tape guide system (not shown) is inserted into the cut-out
portion 3a. The guide system draws out some of the
magnetic tape and loads it onto the rotary drum of the
recording and reproducing apparatus, and then the desired
recording or playback can be carried out. Reference
numeral 32 designates the base of the reel shaft 31.
When the magnetic tape cassette is taken out of
19 service and returned to a standby condition, a procedure
opposite to that described above is carried out.
It will be apparent from the preceding
description of the preferred embodiments of the invention
that many modifications and variations can be effected by
one skilled in the art without departing from the scope of
the invention. For example, while in the disclosed
embodiments the spring 25 biases the brake member 12 toward
the braking position and the lid 8 in moving from the
closed position to the open position must overcome the
force of the spring 25 in order to release the brake, it is
also possible for a spring to bias the brake member 12
toward the released position and for the lid 8 in moving
from the open position to the closed position to overcome
the force of such a spring in order to apply the brake.
Accordingly, the scope of the invention should be
determined by the appended claims only.
