Tape cassette brake assembly

In a cassette for use in a magnetic recording and/or reproducing apparatus and which is of the type having a housing containing freely rotatable reels having magnetic tape wound thereon with the tape extending between said reels being guided to direct a run thereof across an access opening in said housing, an improved brake assembly is provided for automatically preventing excess slackness in the run of tape when the cassette is disengaged from the magnetic recording and/or reproducing apparatus and for automatically releasing the tape run when the cassette is so engaged. A holder having a resiliently flexible element slidably disposed in a gap provided therein is arranged with respect to a support element such that the free end portion of the element preferably having a low coefficient of friction normally urges a tape portion into pressing contact with the support element so as to provide the braking action. When the tape run is drawn out of the access opening or otherwise tensioned, however, the element is flexed thereby such that only the free end portion having the low coefficient of friction is in sliding contact with the tape, whereby the automatic release action is provided.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to tape cassettes for use in 
magnetic recording and reproducing apparatus, and more particularly, to a 
tape cassette of the type in which the tape is wound on and is guided 
between freely rotatable reels in the cassette housing. Specifically, the 
present invention is directed to improved elements for preventing undue 
slackness in the run of the tape extending across the opening of the 
casette housing when the casette is removed from the magnetic recording 
and/or reproducing apparatus and for providing automatic release of the 
run of the tape during recording and reproducing operation of such 
apparatus. 
2. Description of the Prior Art 
Tape cassettes for use in magnetic recording and/or reproducing apparatus 
are well known in the art. Particularly in the case of tape cassettes used 
in video recording and/or reproducing apparatus, it is necessary for 
proper recording and reproducing operations to withdraw the magnetic tape 
from within the cassette housing and to wrap or load the withdrawn tape 
about at least a portion of the periphery of the guide drum adjacent the 
rotary magnetic head which scans skewed record tracks on the tape as the 
tape is moved about the guide drum. 
The required removal of the magnetic tape from within the cassette housing, 
however, creates several problems. When, for example, the tape cassette is 
loaded into a video recording and/or reproducing apparatus having an 
automatic loading device, the tape engaging member of the automatic 
loading device extends into the opening of the cassette housing to engage 
the tape. When the tape is engaged, the engaging member is actuated or 
moved in a path that extends out of the tape cassette housing and ends 
with the magnetic tape wrapped or loaded about the guide drum. Thus, the 
magnetic tape must be freely drawn out of the opening in the casette when 
the engaging member of the automatic loading device is operated. Moreover, 
the magnetic tape must be freely drawn out of the opening in the cassette 
during either the record or reproduction mode. 
While the magnetic tape must be freely drawn out of the opening during 
either the loading, record, or reproduction mode, as described above, 
excessive looseness or slackness in the run of the magnetic tape is 
disadvantageous. Excessive looseness or slackness in the run of the 
magnetic tape causes the magnetic tape not to follow a substantially 
straight path between the guides provided within the cassette housing at 
opposite sides of the opening. Thus, the excessive looseness or slackness 
in the magnetic tape run causes the magnetic tape not to be properly 
engaged by the magnetic head or by the tape engaging member of the tape 
loading device, which often leads to damage of the magnetic tape or 
defective recording or reproducing operations. Moreover, excessive 
looseness or slackness of the magnetic tape often leads to damage of the 
extended run of magnetic tape during storage or non-use of the tape 
cassette. 
There are several known approaches for preventing excessive looseness or 
slackness of the extended run of magnetic tape of the tape cassette. One 
approach is to provide the tape cassette or magazine with brakes for 
holding taut or preventing undue slackness in the run of magnetic tape. 
Such approach was disclosed in U.S. Pat. No. 2,894,700. 
Another approach is disclosed in U.S. Pat. No. 3,797,779, assigned to the 
assignee of the present invention. In U.S. Pat. No. 3,797,779, as shown in 
FIGS. 1 to 3, slackening of the tape run T.sub.1 which traverses the 
opening 15 of the cassette housing 11 as a result of free turning of the 
tape reels 16, 17 within the cassette housing 11 when the cassette 10 is 
apart from the magnetic recording and/or reproducing apparatus, is avoided 
by providing resiliently flexible elements 24, 25, each being fixed at one 
end within the cassette housing 11. Specifically, resiliently flexible 
elements 25, 24 each have an end portion 25a or 24a cemented or otherwise 
suitably secured to partition 21 or 21', respectively, as shown in FIG. 2. 
Alternatively, resiliently flexible elements 25, 24a are secured by an 
adhesive provided on the end portions 25a, 24, respectively, as designated 
by reference numeral 18 in FIG. 4. The resiliently flexible elements 25, 
24, in this case, are secured to the partitions 21, 21', respectively, by 
the peeling off of the release paper provided over adhesive portions 18 
and by manually positioning and contacting the end portions 25a, 24a with 
the respective partitions 21, 21'. 
After the resiliently flexible elements 25, 24 have been secured to the 
respective partitions 21, 21', the free ends of elements 25, 24 engage 
their respective portions of the tape between a respective one of the tape 
reels 16, 17 and the tape run T' for urging the respective tape portion 
into a relatively tortous path in which the tape is engaged by a fixed 
surface, which may be on guide members 26, 18, respectively. The tortuous 
paths impose an increased resistance to movement of the tape into the tape 
run. Each resiliently flexible element 25, 24 is deflected in response to 
tension in the respective engaged tape portion to permit the latter to 
follow a relatively less tortuous path in which the resistance to movement 
of the tape is reduced to free substantially the tape for transfer between 
the reels. 
The use of the resiliently flexible elements 25, 24 to prevent excessive 
looseness or slackness of the extended run of magnetic tape of the tape 
cassette exhibits several major deficiencies. The fastening of the end 
portions 25a, 24a to the partitions 21, 21' is not reliable over a long 
time period primarily because of drying of the adhesive or cement used to 
fasten the end portions 25a, 24a to the partitions 21, 21'. The pressure, 
for example, finger pressure, used when the end portions 25a, 24a are 
fastened to the partitions 21, 21' inherently is not of a constant value 
from end portion to end portion. Leakage of adhesive or cement from the 
sides of the end portions 25a, 24a to the inside of the cassette causes 
contamination of the magnetic tape. Leakage of adhesive or cement is very 
difficult to prevent, especially over a long period of time. Exact 
positioning of the end portions 25a, 24a with the partitions 21, 21' when 
the end portions 25a, 24 are attached to the partitions 21, 26 is 
difficult to achieve. Because the end portions 25a, 24a must be exactly 
positioned with the partitions 21, 21', fabrication is not suitable for 
automatic machine assembly. In addition, the required fastening of the end 
portions 25a, 24a with the partitions 21, 21' is expensive to perform, and 
requires complex manual fabrication steps. 
SUMMARY OF THE INVENTION 
It is the object of the present invention to provide an improved brake for 
a cassette which does not exhibit the above-noted deficiencies present in 
conventional cassette brakes and the like. 
More particularly, it is an object of this invention to provide, in a 
cassette for use in a magnetic recording and/or reproducing apparatus and 
which is of the type having a housing containing freely rotatably reels 
having magnetic tape wound thereon with the tape extending between said 
reels being guided to direct a run thereof across an access opening in 
said housing, an improved brake for automatically preventing excess 
slackness in the run of tape when the cassette is disengaged from the 
magnetic recording and/or reproducing apparatus and for automatically 
releasing the tape run when the cassette is so engaged. 
In accordance with an aspect of this invention, a holder having a 
resiliently flexible element slidably disposed in a gap provided therein 
is arranged with respect to a support element such that the free end 
portion of the resiliently flexible element, preferably having a low 
coefficient of friction, normally urges a tape portion into pressing 
contact with the support element so as to provide the braking action. When 
the tape run is drawn out of the access opening, however, the element is 
flexed thereby such that the free end portion having the low coefficient 
of friction is only in sliding contact with the tape, whereby the 
automatic release action is provided.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 5, it will be seen that, in the embodiment of the present 
invention there illustrated, elements corresponding to those described 
above with reference to FIGS. 1-4 are identified by the same reference 
numerals. 
The tape cassette 10 of the present invention, as shown in FIG. 5, has a 
housing 11 divided into a top half 11' and a bottom half 11". The housing 
11 is preferably of a flat, substantially rectangular configuration which 
may be formed of a suitable plastic, and consists of a top wall 12 (not 
shown on FIG. 5), a bottom wall 13 and a peripheral wall 14 joining the 
margins of top and bottom walls 12 and 13. The peripheral wall 14 and 
adjacent portions of top and bottom walls 12 and 13 are cut away along one 
relatively long side of rectangular housing 11 to define an elongated 
opening or cutout 15. Reels 16 and 17 are suitably located within cassette 
housing 11 so as to be freely rotatable in side-by-side relation, and a 
magnetic tape T is wound on reels 16 and 17 and is guided therebetween by 
guide pins 18 and 19 located adjacent the opposite ends of opening 15. 
Thus, a run T' of the magnetic tape extending between guide pins 18 and 19 
runs along or traverses the opening 15 and may be engaged and withdrawn 
from cassette housing 11 through such opening as hereinafter described. 
The cassette housing 11 may further have a partition 21 extending between 
top and bottom walls 12 and 13 intermediate guide pins 18 and 19 along the 
edge of cutout or opening 15 in bottom wall 13 and being disposed inwardly 
or forwardly in respect to run T' of the magnetic tape extending between 
guide pins 18 and 19. 
In accordance with the present invention, excessive looseness or slackness 
in tape run T' by reason of free rotation of reels 16, 17 is prevented by 
the resiliently flexible elements 100, 102, which are respectively 
associated with a tape portion X1 between guide pin 19 and a support 
member 104, such as a roller, and with the tape portion X2 between guide 
pin 18 and a support member 106, such as a roller. The free end 100' of 
the resiliently flexible element 100 normally urges tape portion X1 into 
pressing contact with a portion of the outer surface of support member 104 
and, thus, normally provides braking action to the tape from reel 16. 
Similarly, the free end 102' of the resiliently flexible element 102 
normally urges tape portion X2 into pressing contact with a portion of the 
outer surface of the support member 106 and, thus, normally provides 
braking action to the tape from reel 17. When, however, tension is applied 
to tape portion T', for example, during loading, recording, or 
reproduction, so as to draw the tape portion T' away from opening 15, tape 
portion X1 draws free end 100' away from pressing contact with support 
member 104 and tape portion X2 draws free end 102' away from pressing 
contact with support member 106 . Thus, the drawing of tape portion T' 
away from opening 15 automatically causes free ends 100', 102' to no 
longer be in pressing contact with their respective support members 104, 
106, thus allowing the tape portion T' to be freely drawn out of the 
opening 15. In other words, free ends 100', 102' together with support 
members 104, 106 prevent excessive slackness in the tape portion T' when 
the cassette 10 is removed from the magnetic recording and/or producing 
apparatus (not shown), and also provide automatic release of the tape T so 
that the tape T can be freely transferred between reels 16, 17 when the 
tape portion T' is drawn out of the opening 15 during the loading, 
recording and reproducing operations. 
In accordance with the present invention, the fixed end 100" of resiliently 
flexible member 100 and the fixed end 102" of the resiliently flexible 
member 102 are not attached by cement or adhesive to a partition provided 
within the cassette housing 11, as is the case in the conventional 
cassette 10 discussed above. Instead, as is discussed in detail below, the 
fixed ends 100" and 102" are slidably disposed in respective holders 110, 
112, as shown in FIG. 5. The use of holders 110, 112 instead of cement or 
adhesive substantially eliminates all of the deficiencies produced 
thereby. 
The first embodiment of the holder 110 or of the holder 112 is shown in 
FIG. 6. Because holders 110 and 112 are identical in configuration in the 
first embodiment, only holder 110 is described. Holder 110 includes a wall 
120, a wall 122, an end wall 124, and a bottom wall 126. Walls 120, 122 
are arranged so as to be substantially parallel and to define a relatively 
wide gap therebetween. A projection 128 is provided along the inner 
surface of wall 120 facing wall 122, and defines a narrow gap, the 
thickness of which is, for example, substantially equivalent to the 
thickness of the flexibly resilient member 100 at the fixed end 100". 
Similarly, a projection 130 is provided along the inner surface of wall 
122 facing wall 120, and defines a narrow gap, the thicknss of which is, 
for example, substantially equivalent to the thickness of the flexibly 
resilient member 100 at the fixed end 100". A tang 132 is provided on the 
inner surface of bottom wall 126 adjacent end wall 124 and extends 
upwardly, as shown best in FIG. 7. 
The first embodiment of the resiliently flexible elements 100, 102 adapted 
to be slideably disposed within the first embodiment of holder 110 is 
shown in side view in FIG. 8 and in top plan view in FIG. 9. Because 
resiliently flexible elements 100, 102 are identical in configuration in 
the first embodiment, only resiliently flexible element 100 is described. 
As shown in FIGS. 8 and 9, resiliently flexible elements 100 is provided 
at the top of its fixed end portion 100" with a cut-away portion 135', and 
is provided at the bottom of fixed end portion 100" with a cut-away 
portion 135". The area of the cut-away portion 135" must be substantially 
equal to or slightly greater than the cross-section of tang 132, as is 
described in detail below. 
Resiliently flexible element 100 may be formed from a strip of suitably 
resilient plastic, such as, polyester resin, or of a spring metal which is 
relatively highly flexible. A or coating 138 exhibiting a low coefficient 
of friction is disposed along the two outer side surfaces of the free 
portion 100' of resiliently flexible element 100. Suitable materials for 
coating 138 include polytetrafluoroethylene, etc., or materials containing 
carbon or gaphite. The material 138 is suitably attached to or pressed 
onto free end portion 100' using an adhesive, cement, heat or mechanically 
activated bonding technique, or the like. 
As shown in FIG. 5, the first embodiment of holder 110 is attached at its 
bottom plate 126 to bottom wall 13 of the cassette housing 11 in a 
position adjacent support member 104 so that when resiliently flexible 
element 100 is slideable disposed at its fixed end 100' in holder 110, the 
free end 100' is normally urging tape portion X1 into pressing contact 
with a portion of the outer surface of support member 104. Because 
material 138 is provided at the free end 100' and is in physical contact 
with the tape portion X1, when tape portion T' is drawn away from opening 
15, very little sliding friction is present between tape portion X1 and 
material 138, and, thus, the automatic release occurs at a low tension 
level. 
As shown in FIGS. 7 and 10, the first embodiment of resiliently flexible 
element 100 is slidably disposed at the fixed end portion 100" in the 
first embodiment of holder 110 in the gap between walls 120, 122. 
Specifically, fixed end portion 100" is disposed in the narrow gap between 
projection 128 and the inner surface of wall 122, and in the narrow gap 
between projection 130 and the inner surface of wall 120. In addition, 
tang 132 is engaged within cut-away portion 135", and the bottom edge of 
fixed end 100" is in contact with the top surface of bottom wall 126 and 
the end portion edge of fixed end 100" is in contact with the inner 
surface of end wall 124. As shown in FIG. 10, the narrow gaps defined by 
projections 128 and 130 do not fall within the same plane defined by fixed 
end portion 100" in its normal unflexed flat state. Thus, fixed end 
portion 100" must be flexed due to projections 128, 130 when it is 
slidably disposed within holder 110. This flexing of fixed end portion 
100" acts to securely hold it in holder 110. In addition a tang 132' can 
be provided, if desired, on the inner surface of the top wall 12, as shown 
in FIG. 20, for engagement with the top cut-away portion 135' when the top 
wall 12 and the bottom wall 13 of cassette housing 11 are fastened 
together. In this case, the fixed end portion 100" of the first embodiment 
of the resiliently flexible element 100 is securely held in the first 
embodiment of holder 110 when top wall 12 is fastened to bottom wall 13 
because of the physical contact of the edges of fixed end portion 100" 
with the adjacent walls, the flexing of the fixed end portion 100" by 
projections 128, 130, and the engagement between tang 132 and cut-away 
portion 135" and between tang 132' and cut-away portion 135'. It should be 
noted that the space between walls 120, 122 is substantially wider than 
the narrow gaps defined by the projections 128, 138, and this space 
permits the free end portion 100' of the resiliently flexible element 100 
to be flexed, as shown in FIG. 10, between the normal braking position and 
the automatic release position. It is apparent that the major 
disadvantages inherent in the conventional approach where an adhesive or 
cement is used to fasten the fixed end is not present in present invention 
where the fixed end portion 100" is accurately positioned by slidably 
inserting the fixed end portion 100" of the first embodiment of the 
resiliently flexible element 100 into the first embodiment of the holder 
110 according to the present invention. 
An alternate version of the first embodiment of the resiliently flexible 
element 100 is shown in FIG. 11. Because the resiliently flexible elements 
100, 102 are identical in configuration in this alternate embodiment, only 
resiliently flexible element 100 is described. The difference between the 
alternate embodiment shown in FIG. 11 and the first embodiment, as shown 
in FIG. 8, is that a pair of projections 140', 140 are provided instead of 
the cut-away portions 135', 135". Thus, a holder 110 in which the fixed 
end portion 100" having projection 140 is slidably disposed must be 
provided with a recess (not shown) along bottom wall 126 instead of tang 
132. In addition, a recess must be provided in the top wall 12 of the 
cassette housing 11 instead of tang 132'. 
A second alternate version of the first embodiment of the resiliently 
flexible element 100 is shown in FIG. 13. Because the resiliently flexible 
elements 100, 102 are identical in configuration in this second alternate 
embodiment, only resiliently flexible element 100 is described. The 
difference between the second alternate embodiment of FIG. 13 and the 
first embodiment, as shown in FIG. 8, is that a single projection 140 is 
provided instead of the cut-away portion 135". Thus, a holder 110 in which 
the fixed end portion 100" having a projection 140 (FIG. 13) is slidably 
disposed must be provided with a recess (not shown) along bottom wall 126 
instead of tang 132. 
The second embodiment of the resiliently flexible element 100 is shown in 
side view in FIG. 12. Because the resiliently flexible elements 100, 102 
are identical in configuration in the second embodiment, only resiliently 
flexible element 100 is described. A cut-away portion 150 is provided at 
the bottom of the fixed end portion 100" in a fashion substantially 
similar to the cut-away portion 135' of the first embodiment of FIG. 8. In 
addition, material 138 is provided at the free end portion 100' to reduce 
the sliding coefficient of friction between the free end portion 100' and 
the tape T. The difference between the first and second embodiments is 
that in the second embodiment at least one cut-out portion 152 is provided 
in the resiliently flexible element 100 between the free end portion 100' 
and the fixed end portion 100". As shown in FIG. 12, a cut-out portion 152 
is provided along the lower edge and a cut-out portion 152' is provided 
along the upper edge of the resiliently flexible element 100. The cut-out, 
portion 152, 152' allow the amount of tension on tape T' required to move 
the resiliently flexible element 100 between the normal braking position 
and the automatic release position to be changed or preselected. 
The second embodiment of the holder 110 is shown in FIGS. 14-16. Because 
the configuration of holder 112 is an identical mirror image of holder 
110, only holder 110 is described. Holder 110 of FIGS. 14-16 is formed 
from a block 160 provided with an arcuate gap defined by wall surfaces 162 
and 164. The gap between wall surfaces 162 and 164 is greater than the 
thickness of the resiliently flexible element 100 that is slidably 
disposed therebetween, as shown in FIG. 16. The gap defined by wall 
surfaces 162 and 164 is opened at the top and at one end, and is closed at 
the other end by an end wall 162. A tang 132 is provided on the inside 
bottom surface of the gap adjacent end wall 162. 
As stated above, resiliently flexible element 100 normally assumes a flat 
shape. Thus, because of the arcuate shape of the gap defined by wall 
surfaces 162 and 164, the resiliently flexible element 100 is held therein 
due to flexing, and cannot be pulled out because of the engagement of tang 
132 with a cut-away portion in the resiliently flexible member 100. 
An alternate version of the second embodiment of holder 110 is shown in 
FIG. 22, and is formed integrally with the bottom wall 13 of the cassette 
housing 11. The alternate version of the second embodiment of holder 110 
includes a wall 170 having an arcuate shape. The outer surface of wall 170 
facing away from spool 16 corresponds to wall 162 of FIG. 14. The other 
surface in the alternate version of holder 110 is defined by the end 
surface of a member 172, the end surface of a member 174 and a flattened 
surface portion of a fastening member or boss 176. It should be noted that 
a tang 178 is provided between member 174 and the adjacent arcuate surface 
of wall 170. In addition, a projection 180 is provided on fastening member 
176 adjacent the end of wall 170. 
When the resiliently flexible element 100 is inserted into the alternate 
version of the second embodiment, as indicated by the dotted lines in FIG. 
22, member 100 is flexed by the arcuate shape of wall 170 and by 
projection 180 and is prevented from being pulled out by the engagement of 
tang 178 with a corresponding cut-away portion in member 100. Thus, the 
free end portion of member 100 normally urges the tape portion X1 into 
pressing contact with support member 104, thereby to create the braking 
action. When the tape is drawn out of opening 15, however, the tension on 
tape portion X1 flexes member 100 away from support member 104, and tape 
portion X1 is in low-friction sliding engagement with material 138 on the 
free end portion of member 100, as shown in FIG. 22. 
A second alternate version of the second embodiment of holder 110 is shown 
in FIG. 21, and is formed integrally with the bottom wall 13 of the 
cassette housing 11. 
A third embodiment of the resiliently flexible element 100 is shown in FIG. 
17. Because the configuration of resiliently flexible element 102 is 
identical to that of resiliently flexible element 100, only resiliently 
flexible element 100 is described. Element of FIG. 17 is bent around on 
itself at free end portion 100' so that the angle .alpha. defined between 
the bent around portion 192 and the balance of free end portion 100' 
satisfies the condition of .alpha..ltoreq.45.degree.. A cut-away portion 
190 is provided at the bottom rear portion of the fixed end portion 100". 
The resiliently flexible element 100 may itself be formed from a resilient 
material having carbon or graphite or other material which produces a 
low-coefficient of friction at the free end portion 100'. Thus, in the 
third embodiment of the resiliently flexible element 100 shown on FIG. 17, 
it is unnecessary to provide the material 138 because the low-coefficient 
of friction is inherent in the material used to fabricate the resiliently 
flexible element 100. 
A fourth embodiment of the resiliently flexible element 100 is shown in 
FIG. 18. Because the configuration of resiliently flexible element 102 is 
identical to that of resiliently flexible element 100, only resiliently 
flexible element 100 is described. Like the third embodiment, the fourth 
embodiment has a bent around portion 192 at the free end that satisfies 
the condition of .alpha..ltoreq.45.degree.. A cut-away portion 190 is 
provided at the bottom rear portion of the fixed end 100". The difference 
between the third and fourth embodiments is that the material which is 
used to fabricate element 100 in FIG. 18 does not exhibit a sufficiently 
low coefficient of friction. Thus, material 138 must be attached at least 
along the entire outer surface of the free end portion 100' and the bent 
around portion 192 in the embodiment shown in FIG. 18, or along the entire 
outer surface of element 100 including the bent around portion 192 in the 
embodiment shown in FIG. 19. 
The third and fourth embodiments of the resiliently flexible elements 100, 
102 shown on FIGS. 17-19 are, of course, to be, mounted in appropriate 
holders 110.