Note: Descriptions are shown in the official language in which they were submitted.
64~3
, ,
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates in general to tape cassettes and in
particular to a novel tape cassette.
Description of the Prior Art
In prior art tape cassettes the front tape guides which guide
the tape by the magnetic heads are generally molded on either the
upper or lower cassette half as one unit and are designed to guide the
tape passed the front edge portion of the cassette. The cassette is
normally made of plastic synthetic resin and it has been found that the
guides inclille or tilt backwardly after being removed from the mold in
which the cassette housings are formed. The guides tend tO tilt toward
the inside direction of the cassette housing perhaps because the guides
thermally shrink after being removed from the mold. For example if
the guide is 4 mm in height, the free end of the guide is misaligned
by 40 microns inwardly of the housing. .
Thus, the prior art machines have utilized guide members
extending from one side of the cassette wl~ich tilt backwardly into the
..
confines of the cassette and thus result in the tape being transported -~
in a manner which tends to bias i~ up or down in the cassette or tends
to cause it to wave in one direction which is undesirable and will
result in the tape being urged toward the bottom or top wall of the
cassette housing depending upon the angle of tik and the side from which
the pins extend.
Thus, also when the cassette is ~urned over for recording
or reproducing a signal on the other side of the tape, the tape will
also be biased or urged against the same side wall of the casse~e
_z_-
~-
.'~' ' ' .
,
- 1064~S~
which causes the magnetic head lo be misaligned with the magnetic
track on the tape which causes the reproduction to be of poor quality.
This of course presents a large problem for recording or reproducing
signals with the proper high quality sound which is desired.
SUMMARY OF THE INVENT~ON
Therefore, the present invention provides molding tape
guldes partially on the upper cassette half and partially on the lower
cassette half with approximately one-half of the guides on the upper
cassette half and the other half on the lower cassette half and wit~
the guides spaced so that they interleaf between each other. In a
particular embodiment two guides extend from the upper half and two
guides extend from the lower half with the guides interleafed between
each other such that even if each guide tilts inwardly the tape will pass
and be maintained in the center poxtion of the cassette by the tape guides
which causes the magnetic recording and/or reproducing head to engage
the tape in the desired position.
Another feature of the invention is that the head pads are
supp~rted by a leaf spring which is attached to one half of the cassette
by guides which are molded into the cassette. One supporting guide
extends from the tape guide on one side and the other silpporting guide
is mounte~l symmetrically in the cassette and a.center support guide
engages the center of the spring and thus the spring is supported
between the guides under a spring biasing force.
Another feature of the invention is providing a plurality
of projections on the inside walls of the cassette housing so as to
prevent the magnetic tape from sticking. The various thin film tapes
used with micro-cassettes tend to stick to the walls as the tape ,~;
': ' '
-3- ~:
:~:
,,, , ,, , ,,, ., , ,, ,
-1064~53
becomes ~lack parcicularly und~r humid conditions. Also during mold
of the cassette h~using a silicon type oil is used for removing the
cassettes from the mold which sometimes remains OD the wall sur-
~aces and causes the magnetic tape to stick thereto. The projections~
prevent such sticking.
In accordance with the foregoing features, there is
provided~
a tape cassette having a pair of parallel lower and upper
cassette hal~es, a pair of tape reels disposed side by side in
a common plane between said halves and a magnetic tape w~und ::
onto at least one of said reels comprising:
a. tape guide rollers for defining at least part of the tape - .
transport path; and
b. a plurality of tape guides formed on said cassette halves ~
with a first group of said tape guides formed on said .
lower half and another group of said guides formed on
.~. said upper half and said tape guide project from said
cassette halves so that tape guides of said first group
interleave with tape guides -of said second group, and
said magnetic tape engages surfaces of said first and
, another groups of said guides which hold it centered
between ~aid lower and upper cassette halve~.
There i~ also provided~
a tape ca~sette formed of molded plastic and having a
- pair of mating lower and upper cassette ~embers and including
a pair of tape reels rotatably mounted in said cassette with
magnetic tape extending between said reels and having a portion
; available for recording and playback functions along a front
sidewall of said cassette which has an open area, comprising
a plurality of tape guides formed on said lower and upper
cassette members and extending generally parallel to ~aid front
. .
~-4- j
, ..
, ~ ~
. -. : . , ' ,:: .
_~ -10644~3
face of said casset~ë and~providing guides for said tape
~ at said front face and a first portion of said tape guides
attached to said upper cassette member and a second portion
of said tape guides attached to said lower cassette member
and said first and second portions interleaved between each
other such that said tape engages alternately guides from
said first and second portions, and said first and second
portions maintaining said tape centered between said lower
and upper cassette members.
- 10 Other objects, features and advantages of the invention wi~:
be readily apparent from the following description of certain preferred
embodiments thereof taken in conjunction with the accompanying
drawings although variations and modifications may be effected without
departing from the spirit and scope of the novel concepts of the
disclosure and in which:
BRIEF DESCRIPI'ION OF THE DRAWINGS : :
. , .
Figure 1 is a perspective view of a cassette according to
the invention;
Figure 2 is a top plan view of a prior art cassette;
; 20 Figure 3 is a sectional view taken along line III-III in
Figure 2;
Figure 4 is a sectional view through the cassette;
Figure 5 is a sectional view through the casse~te
illustrating certain of the internal parts mounted therein; ;
Figure 6 is a sectional view taken along line VI-VI in
Figure 5;
Fi~ure 7 is a detailed perspective view of the pad `~
supporting spring;
.. ,~ .
-4a-
:
, . . . : :
.:
io644~3
Figure 8 is an enlarged dOEailed view taken on sectic>n
lines VIII-~TIIl from ~igure S;
Figure 9 is a partially cu~-away ~ectional top view through
-4b-
'
~ 10644~3
.
the cassette illustrating the pinc ll roll and recording heads; and
Figure 10 illustrates a partial sectional view sl-owing a
pinch roller of the side~type.
DESCRIPTION OF THE PREFERRED EM13ODIMENTS
. . _ _
Figures 1, 2 and ~ illustrate cassettes of the prior art.
The cassette 10 is made of two halves 11 and 12 which are held to-
gether by bolts 13, 14 and 16. Feeler openings 17 and 18 are formed
near the rear wall of the cassette so as to prevent erasure of the
tape if desired. Reels 19 and 22 are rotatably supported in the -;
cassette and have projections 21 and 23 for tape drive and rewind.
Openings 24, 26 and 28 extend through both halves of the cassette and `~
corner guide rollers 29 and 31 are mounted adjacent the front edge of
the cassette and the tape 32 passes over them and by the vertical
guides 33, 34, 36 and 37. Extending upwardly from the lower half 12
of the cassetteareguide members 38, 39, 41 and 42 all of which are
attached to the lower half 12 and extend upwardly therefrom and are
of generally cylindrical shape. A rear spring receiving notch 51 is
formed iD the rear of the cassette to hold it in the tape machine.
With such prior art tape cassettes, the tape guides 38,
39, 41 and 42 which are attached to only one of the halves 12 of the
cassette tend to have their ends away from the base which is attached
to the cassette half 12 bent or inclined into the body of the cassette
as shown in Figure 3 in dotted line. Generally, such guides in micro-
cassettes are about 4 mm in height and the top of the guides is
shifted or displaced upwardly relative to Figure 3 by about 40 microns.
This is caused prirnarily due to heat shrinking as the cassette halves
are removed from the mold in whlch the cassette halves are formed
~5~
.. . . . .. . . . . . .
,~o~ 4~5 3
and during cooling the guide berld as shown in Figure 3 in dotted line.
Figures 4, 5 and 6 illustrate the invention in which the ~ -
cassette halves lla and 12a are formed with openings 26, 27, 28 and
24 and support reels 19 and 22 upon which the tape 32 is carried.
Behind the protector members 33, 34, 36 and 37 are mounted guide
members 52 and 54 which extend upwardly relative to Figure 6 from
the bottom half 12a of the cassette Additional guide members 57 and
58 extend downwardly relative to Figure 6 from the cassette half lla
and the guide members 52, 57, 54 and 58 are interleaved between
each other as shown in Figure 6. When the tape rides against the
surface of the guides, 52, 57, 54 and 58 it will ride in the center of
~he cassette between the cassette halves lla and 12a because the tOp
ends relative to Figure 6 of guide members 52 and 54 will be bent
back into ~he cassette due to heat shrinking whereas the lower ends
relative to Figure 6 of guides 57 and 58 will be bent into the cassette.
The result is that the bending of guides 52 and 54 will be compensated
for by the bending of guides 57 and 58 such that the tape 32 will run
in the center relative to Figure 6 of the front opening in the cassette
; such that magnetic heads will maintain alignment with the tape and,
thus, improved reproduction will occur.
~`~' Also, when the tape is turned over for recording or repro-
ducing a signal on its other side the tape will be biased toward the
center of the cassette and proper alignment will exist thus allowing
the recording and reproduction of signals with high fidelity.
Thus, in accordance with the present invention the tape
guides 57 and 58 are molded ~nd extend downwardly from the upper
casse~e lla whereas the tape guides 12 and 54 extend upwardly and
are molded from the lower cassette half 12a as shown in Figures
--6--
,~
106~g~5~
4, 5 and 6.
Even though each of the guides tilts inwardly, the tape
will pass at the center of the cassette and exact alignment with mag-
netic recording and/or reproducing heads will be obtained.
Wiper pads 42 and 43 are mounted on a leaf spring 61
as illustrated in perspective view in Figure 7 and have end tabs 64
and 66 at its opposite ends which engage spring guides 53 and 56. A
center sprmg engaging member 62 is formed in the cassette and the
spring is held between the guides 53, 56 and member 62 as shown in
Figure 5, for example. As the tape 32 passes the wiper pads 42;and
43, it will be wiped and cleaned by the pads 42 and 43. The guide 53
is attached to and extends from the guide 52 and guide 56 is symmetri
cally spaced relative to guide 53. The spring 61 is maintained betwee~
the spring support 62, 53 and 56 due to spring tension in the spring.
On the side walls 91a and 91d of the lower half of the
.
cassette 12a as well as the side walls 91b and 91c of the upper half
lla of the cassette are formed a number of projections 98a, 98d,
98b and 98c. As shown in greater detail in Figure 8, the projections
98 may comprise a number of individual projections 92, 93, 94 and 96
which extend from the side wall 91 adjacent the bottom wall 97 of the
cassette. The projections 98 engage the tape 32 and prevent it from
... :
sticking to the side walls of the cassette. The very thin film tape
used with Micro Cassettes tends to stick to the walls wh~n the tape
is slack in the cassette housing due to high humidity conditions. Also,
silicon oil is used for removing the molded cassette housings from the
mold during manufacture and such oil remains on the wall surfaces
and causes the magnetic tape to stick thereon. The prcjections 98
hold the tape away from the wall and prevents such sticking. Although
-7-
1()6~5;3
the projections 92 through 93 al-~ illustrated as triangular in cross-
section in Figure 8 it is to be realized, of course, that they may be
rounded or of any suitable shape so as to hold the tape away from
the side walls 91 of the cassette.
It is seen that this invention provides for a proper
alignment in tape cassettes by forming tape guides from opposite halves
of the cassette such that they interleaf between each other which
provides accurate guiding of the ~pe. The invention also encompasses
a novel leaf spring and support for head pads and projections on the
side walls of the cassette for preventing sticking. ;
Figure 9 is a sectional view illustrating the cassette of
the invention in use with a center pinch roll 81 and center capstan
82 which extends through the opening 27. Magnetic heads 83 and 84
are Inounted so as to engage the tape 32.
Figure 10 illustrates a side drive with a pinch roll 86
:. ~
which engages a capstan 87 that passes through opening 26 in the
cassette and magnetic heads 88 and 89 are mounted so as to engage
the tape 32.
Although the invention has been described with respect
to preferred embodiments it is not to be so limited as changes and
modifications may be made which are within the full intended scope
as defined by the appended claims.
