Note: Descriptions are shown in the official language in which they were submitted.
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04445-32 RDF
Cassette Reel Lock Control A~aratus
This invention relates to a means to control the locking of
a cassette reel against rotation in a forward feed direction.
U.S. Patent No. 4,632,335 to Dickson et al. issued December
30, 1986 discloses a tape cassette having a locking mechanism which
allows the tape to be played in a forward feed direction but which
locks the tape against rewinding unless unlocking pins of
appropriate length are inserted into the locking mechanism. Such
a cassette, when recorded with a video taped movie, allows for the
rental of the cassette on a single play basis since only the rental
outlet will have at its disposal a means to unlock the cassette to
alLow rewinding. ~lowever, the cassette suffers the drawback that
the renter is unable to replay any segments oE the rented movie.
Further, the movie must be returned to the rental outlet without
being rewound, which increases the overhead before the cassette may
be rented again.
The subject invention seeks to overcome drawbacks of known
cassette locking mechanisms. According to the present invention
there is provided a tape cassette comprising: supply reel means;
take-up reel means; lock means for locking at least one of said
supply reel means and said take-up reel means against rotatlon in
a forward feed direction when actuated; indicator means for
indicating the amount of tape on at least one of said supply reel
means and said take-up reel means; lock actuation means enabled by
said indicator means when said indicator means indicates a first
pre-selected amount of tape on one of said supply reel means and
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04445-32 RDF
said take-up reel means, said lock actuation means, when enabled,
responding to said indicator means during rewinding of said tape
for actuating said lock means when said indicator means indicates
a second pre-selected amount of tape on one of said supply reel
means and said take-up reel means whereby said tape is thereafter
inhibited from feeding in a forward feed direction; and reset means
selectively operable to disable said lock actuation means at least
when said lock actuation means has actuated said lock means.
In the figures which provide example embodiments of the
invention,
figure 1 is a plan view oE a tape cassette including a
mechanism made in àccordance with this invention,
figure 2 is a plan view of a portion of a figure 1,
Eiyure 2a is a plan view of portion ox figure 2,
figure 3 is a sectional view along the lines 3-3 of figure 2,
figure 4 is a plan view of a portion of a the tape cassette
of figure 1,
fiyure 4a is a sectional view along the lines 4a-4a of figure
4,
figure 5 is a plan view of a portion of figure 1,
figure 5a is a sectional view along the lines Sa-5a of figure
5,
figure 6 is a perspective view of a portion of figure 1,
fiyures 7 and 8 are front and top views of elements of figure
1,
figure 8a is a sectional view along the lines 8a-8a of figure
,
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04445-32 RDF
fiyure 9 is a front and top view of an element of figure 1,
and
figures lO through 13 are plan views illustrating the
operation of the tape cassette of figure 1.
With reference to figure 1, a tape cassette generally
indicated at 10 comprises a supply reel 12 and a take-up reel 14.
A tape 16 is shown wound around the hub 18 of the supply reel and
extends along one side of the cassette to the hub 20 of the take-
up reel. The forward feed direction for the take-up reel is
illustrated at 62. A lock means for the take-up reel includes
locking arm 92 (detailed in figure 7) and the elements detailed in
figures 2, 2a, and 3.
Referring to figures 2, 2a, and 3, the lock means comprises
an inner locking member 22 having a thickened annular base 24 with
an exterior annular lip 26 and a plurality of interior upstanding
snaps 23 comprisiny leys 30 and shoulders 32. The inner locking
member has a bulbous pawl supporting slot 34 which receives the
complimentarily shaped bulbous base 33 of pawl 36. The pawl has
a convex back 35 protruding in the counterclockwise direction and
a front tapering to a tip 37 in the clockwise direction. An outer
locking member 40 comprises a thin annular disk 41 having a medial
thickened annulus 42 with a triangular notch 44 therein. The notch
slopes to a stop 46 at the clockwise end of the notch. The outer
locking member has an inner diameter less than the diameter oE lip
26 of the inner member such that the outer member rests on the lip
of the inner lockiny member and ma rotate with respect to the
inner locking member. A locking tooth 50 is formed on the
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04445-32 RDF
periphery of the outer locking member ninety degrees from the
triangular notch 44 in a counterclockwise clirection. A displacer
ring 56 rests on the outer locking member between the medial
thickened annulus 42 of the outer locking member and the thickened
annular base 24 of the inner locking member. The displacer rlng
has a clearance fit between thickened annulus 42 and thickened
annular base 24. The displacer ring is gapped and the pawl is
located within this gap. The gap of the displacer ring terminates
at its counterclockwise end in stop 52 and at its clockwise end in
ramp 54.
With reference to figure 1 along with figures 2 and 3, snaps
28 are received in channels 58 of the hub 20 of the take-up reel
with the shoulders 30 of the snaps overlying l:ip5 60 of the hub of
the take-up reel. Accordingly, the inner locking member is fixed
to the take-up reel and rotates therewith. On the other hand, the
take-up reel may rotate with respect to the outer locking member.
Locking tooth 50 of the outer locking member extends beyond the
periphery of the take-up reel.
In the operation of the sub-assembly of figures 2, 2a, and 3,
if tooth 50 is held from rotation and the take-up reel is rotated
in a counterclockwise direction, the inner locking member, and
hence pawl 36, move counterclockwise therewith. The displacer ring
initially remains stationary due to its frictional engagement with
the outer locking member on which it rests. However, if
counterclockwise rotation of the inner locking member continues,
the convex back 35 of the pawl hits stop 52 of the displacer ring
and thereafter pushes the displacer ring in a counterclockwise
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04445-32 RDF
direction. The reactlon force exerted on the back of the pawl by
stop 52 urges the pawl to rotate clockwise within slot 34 of the
inner locking member until a portion of the pawl rests against the
periphery of the inner locking member. In this position, the pawl
moves freely past the triangular notch in the outer locking member.
Thus, the locking means does not impede counterclockwise rotation
of the take-up reel, which is the direction of rotation of the
take-up reel during rewinding of tape from the take-up reel to the
supply reel.
If the take-up reel is rotated in a clockwise direction
(illustrated at 62 in figures 1 and 2) while the tooth 50 is held
Erom rotation, the pawl moves clockwise lnto abutment with ramp 54
of the gap oE the displacer ring whereupon the tip of the pawl is
ramped into abutment with the thlckened medial annulus 42 of the
outer locking member. Continued clockwise rotation of the inner
locking member results in the pawl pushing the displacer ring in
a clockwise direction while the reaction force from the ramp 54 of
the displacer ring results in a continuous counterclockwise torque
on the pawl about its base 33. This torque causes the tip 37 of
the pawl to enter the triangular notch as the pawl i5 rotated
clockwise into re!gistration therewith until the tip of the pawl
comes into abutment with stop 46. At this point, in the clockwise
direction, the inner locking member is locked to the outer locking
member. However, since the outer locking member is held from
rotation, this stops the take-up reel. The clockwise direction for
the take-up reel is the forward feed direction, accordingly, when
the tooth 50 is held from rotation, the take-up reel is inhibited
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04445-32 RDF
from rotating it a forward feed direction but may rotate in a
reverse feed direction.
Returning to figure l, it is noted that the cassette includes
a leaf spring 64 fixed at one end between the supply reel and take-
up reel with its free end inclined toward the take-up reel in the
path of locking tooth 50. Accordingly, when the take-up reel is
rotated in a counterclockwise (reverse Eeed) direction, tooth 50
moves into abutment with the free end of the leaf spring so that
the tooth, and hence the outer locking member 40, thereafter remain
stationary with continued counterclockwise rotation of the take-
up reel. (Recall that with counterclockwise rotation of the take-
up reel, the outer locking member is not locked to the take-up
reel.) When the take-up reel is rotated in a clockwise (forward
feed) direction, the tooth will be stopped by the leaE spring so
that the outer locking member will lock to the take-up reel,
however, the retaining Eorce of the leaf spring is chosen so that
it will not stall the motive force driving the take-up reel. Thus,
the locking tooth deflects the leaf spring and rotates past same.
The cassette has a follower arm 70, rotatably mounted at one
end to post 72. The follower arm has a medially mounted rotatable
wheel 74 and a distally mounted rotatable wheel 76 at the free end
of the follower arm. The follower arm is dimensioned such that at
most one of wheels 74 and 76 is in contact with the tape 16 of the
cassette. The angular position of the follower arm acts as an
indicator of the amount of tape on the supply reel 12 or take-up
reel 14, as follows. First, given that the cassette is initially
in a fully rewound condition and the cassette is then operated in
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04445-32 RDF
a forward feed direction to transEer tape to the take-up reel, as
the layers of tape build on the take-up reel, the outer layer of
tape will eventually contact the medial wheel 74. Thereafter, as
additional layers of tape are wound onto the take-up reel, the
follower arm will deflect in a counterclockwise direction about
post 72 until the last layer of tape is wound off the supply reel.
Accordingly, while the follower arm is deflected counterclockwise
by the layers of tape wound onto the take-up reel, the arm
indicates the amount of tape on the take-up reel by its angular
position. If the tape is then rewound, the outermost layer of the
building layers of tape on the supply reel will eventually contact
the distal wheel 76. Thereafter, additional layers oE tape added
to the supply reel will deElect the follower arm in a clockwise
sense about the post 72. Accordingly, while the follower aft i5
deflected clockwise by the layers of tape wound onto the supply
reel, the arm indicates the amount of tape on the supply reel by
its angular positionO
It is noted that whenever the cassette is switched from
forward feeding to rewinding of the tape, or vlce versa, there is
a "dead zone" during which the angular position of the follower arm
does not change to track the amount of tape on either the supply
reel or the take-up reel since neither of the wheels 74 and 76 are
in contact with the tape. The extent of the dead zone is dependent
on the dimensions of the follower arm and it does not affect the
operation of the invention for reasons which will become apparent
hereinafter. While shaking of the cassette would rotate the
follower arm about within this dead zone, the follower arm is never
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04445-32 RDF
free to rotate clockwise beyond the position illustrated in figure
1 due to stop 78 and is limited in its counterclockwise rotation
by stop 79.
Turning to figure 4, it is seen that the two wheels 74 and 76
of the follower arm 70 are mounted to the arm by three legs: 80a,
80b, and 80c and 82a, 82b, and 82c, respectively. with reference
to figure 4a, it is seen the outwardly facing portion of the heads
84 of the three legs 80 are radiused and are received in a radiused
circumferential notch 86 in the wheel 76. A leg supporting pin 88
is press fit between the three legs 80. The mount for wheel 74 is
of similar construction. In view of this construction, the wheels
74 and 76 are not only free to rotate but also have a limited
Ereedom to pivot on their mounts. This abllity to pivot
compensates or any misalignment between the follower arm and the
reels of the cassette which might otherwise accelerate tape wear.
The legs of the follower arm are positioned so that when wheel 74
or 76 contacts the tape 16 of the cassette, the point of contact
of the tape is between legs 80a and 80b or 82a and 82b,
respectively, for most permissible angles of rotation of the
follower arm. Accordingly, the reaction force on the wheel of the
follower arm is taken up by two legs of the follower arm which
provides good wheel stability and hence minimizes the generation
of noise due to the wheel during tape play.
Returning to figure l the cassette also has a take-up reel
lock actuation means indicated generally at 90. Lock actuation
means 90, as well as the locking arm 92 of the lock means, are
illustrated in greater detail in figures 5 through 9.
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04445-32 RDF
Turning to figures 5, 5a, and 6, locking arm 92 (detailed in
figure 7) is rotatably mounted at one end on post 94. The locking
arm has a deflection face 95, an angled dwell face 96, and an
enlarged locking tip 98. The lock actuation means 90 comprises a
locking arm displacer 100 (detailed in figures 8 and 8a) rotatably
mounted on post 72. A detent 102 is slidably mounted to the
locking arm displacer such that the detent nay slide radially with
respect to the post 72 by virtue of feet 105a and 105b of legs 103a
and 103b of the detent which slidingly engage shoulders 107a and
107b of the locking arm displacer. A compression spring 104 biases
the detent radially inwardly. The locking arm displacer supports
an indicator flag 108. A torsion spring 99 urges the locking arm
92 against the locking arm displacer 100.
As aforenoted, Eollower arm 70 is also rotatably mounted on
post 72. As best seen in figure 10, the follower arm has an
arcuate portion 110 centered about post 72. The arcuate portion
has a notched segment 112 extending in a clockwise direction from
stop 114 and an unnotched segment 116 extending in the other
direction from the stop 114. The arcuate portion 110 of the
follower arm is positioned on post 72 radially inwardly of the
detent 102 of the Locking arm displacer with the detent urged into
abutment with the arcuate portion 110 due to compression spring
104. Consequently, if the detent is abutting the unnotched segment
116 of the arcuate portion of the follower arm (as illustrated in
igure 10) and the follower arm is rotated counterclockwise, the
detent will snap into the notched segment 112 of the arcuate
portion of the follower arm as soon as the detent passes stop 114
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04445-32 RDF
(as illustrated in figure 11). Ihe polnt where this occurs is
referred to herein as the "trigger point"0 Since the follower arm
is rotated counterclockwise by the layers of tape building on the
take-up reel, the trigger point is reached when a pre-determined
amount of tape is wound onto the take up reel. As will be become
clearer hereinafter, the lock actuation means is enabled when the
detent of the locking arm displacer is received in the notched
segment 112 of the follower arm.
Figures 5, 5a, and 6 also illustrate a reset means comprising
reset lever 120 (detailed in figure 9) rotatably mounted to post
72 and biased by torsion spring 122 so that the head 124 of the
reset lever abuts a stack of notched disks 130. Reset lever 120
has a cam 126. torsion spriny 106 urges the locking arm
displacer toward the reset lever; the locking arm displacer is in
its rest position when it abuts the reset lever. With reference
to figure 13, the stack of notched disks have notches 134 and the
notch of the bottom disk 130a in the stack has a camming surface
136; this disk may be considered a camming disk.
Figures 10 through 13 illustrate the operation of the
cassette. Figure 10 shows the cassette with the lock actuation
means in a disabled state, that is, wlth the detent 102 of the
locking arm displacer abutting the unnotched segment 116 of the
arcuate portion of the follower arm. In the disabled state the
locking arm displacer is in its rest position, biased against the
reset lever 120 by torsion spring 106. With the lock actuation
means disabled, the tape may be freely forward fed and rewound
without any effect on the lock actuation means so long as the
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04445-32 RDF
trigger point is not passed. This is for the reason that the
follower arm is not engaged with the lock actuation means when the
lock actuation means is in the disabled state.
If the lock actuation means is disabled and the tape is
forward fed by clockwise rotation of the take-up reel, the follower
arm will rotate counterclockwise about post 72 and the detent 102
will snap into notched segment 112 of the arcuate portion of the
follower arm when the follower arm has rotated to an angular
position such that the detent just clears stop 114. This is the
trigger point; the amount of tape on the take-up reel at the
trigger point is pre-selected by the dimensional choices for the
cassette. Once the detent has snapped into the notched segment oE
the follower arm, the lock actuation means is enabled. Figure 11
illustrates the lock actuation means at the trigger point with the
detent 102 of the locking arm displacer received by the notched
segment 112 of the arcuate portion of the follower arm.
Continued counterclockwise rota-tion of the follower arm past
the trigger point consequent upon continued forward feeding of tape
results in the notched segment 112 of the follower arm sliding
along the face of the detent with the stop 114 rotating
counterclockwise away from the detent since the locking arm
displacer is restrained from following stop 114 by reason of the
fact the locking arm displacer rests against the reset lever 120.
The lock actuation means, when enabled, responds to the
follower arm during rewinding, as follows. Once the building
layers of tape on the supply reel rotate the follower arm clockwise
to the point where the stop 114 abuts the detent 102, further
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04445-32 RDF
rewinding causes stop 114 to deflect the detent, and the locking
arm displacer which carries it, in a clockwise sense about post 72.
Since locking arm 92 is biased against the locking arm
displacer by torsion spring 99, deflection of the locking arm
displacer displaces the locking arm in a counterclockwise sense
about post 94. The dimensions of the device are chosen so that if,
during rewinding, more then a pre-selected amount of tape is built
up on the supply reel when the lock actuation means are enabled,
the follower arm is rotated to an angle whereat the locking arm is
displaced by the lccking arm displacer into the path of the locking
tooth 50. The point at which the locking arm has moved into the
path of the locking tooth is reEerred to herein as the lock-up
point; once the locking arm has reached the lock-up point, the lock
means are actuated, Figure 12 illustrates the cassette with the
lock means actuated.
With the lock means actuated, the cassette may continue to be
rewound and tooth 50 will simply rest on leaf spring 64. However,
if the tape is forward fed, the take-up reel rotates in a clockwise
sense and the tooth moves with the take-up reel until it abuts the
locking arm 92 whereupon the tooth will be blocked from further
clockwise rotation (as is illustrated in figure 12). As explained
in connection with Eigures 2 and 3, continued clockwise rotation
of the take-up reel when the tooth 50 is blocked from rotation will
cause the tooth supporting outer locking member 40 to lock to the
inner locking member 22. And since the inner locking member is
fixed to the take-up reel, this locks the take-up reel against
further clockwise (forward feed) rotation. Of course it remains
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04445-32 RDF
possible to recommence rewinding of the cassette, only forward
feeding is inhibited in the lock-up state
Two purposes of leaf spring 64 are to prevent the possibility
of the locking tooth jamming against the locking arm during
rewinding and to minimize noise. That is/ when the locking arm
has moved to the edge of the path of tooth 50 during rewinding, in
the absence of leaf spring 6~, the tooth would tick against the
locking arm for several revolutions as it passed the locking arm
until the locking arm had been displaced sufficiently that the
tooth would stop against the locking arm. During this period,
there is a possibility of the tooth jamming against the end of the
locking arm. The leaf spring prevents this as it forms a rest Eor
the tooth on rewinding. While it is possible the tooth could tick
past the locking arm on forward Eeed operation, this is unlikely
since the locking arm is only displaced toward the path of the
tooth by rewinding. Consequently, the tooth would only tick past
the locking arm on forward feeding of the tape if the locking arm
had been displaced to the edge of the path of the tooth but not
quite to the lock-up point. If the rewinding went past the point
of lock-up, forward feeding would be inhibited.
Referring to figures 7 and 12, dwell face 96 of the locking
arm is provided to limit the extent to which the locking arm is
displaced, as follows. As the locking arm displacer deflects the
locking arm in a counterclockwise sense about post 94, the free end
of the locking arm displacer initially moves along the deflection
face 95 of the locking arm. Continued deflection of the locking
arm results in the free end of the locking arm displacer moving
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04445-32 RDF
into abutment with the dwell face 96 of the locking arm.
ThereaEter, further rotation of the locking displacer arm in a
clockwise sense about post 72 moves the free end of the locking arm
displacer along the dwell face 96 which maintains the deflection
of the locking arm but does not further deflect same. The dwell
face of the locking arm allows, within certain bounds, one cassette
construction to be used with varying amounts of tape spliced to the
leader tape of the cassette. That is, a cassette is typically
manufactured with only transparent leader tape on the reels. it
a duplicator, magnetic tape is then spliced to this leader tape.
Where the magnetic tape is pre-recorded, the amount of tape that
is to be spliced to the leader tape of the cassette may vary. The
lock-up point is, however, reached when a pre-determined amount of
tape has been wound onto the supply reel irrespective of the length
of the tape spliced to the tape of the cassette. The dwell Eace
of the locking arm keeps the locking at-m in blocking relation with
the locking tooth for difEerent amounts of tape spliced to the tape
of the cassette. That is, the dwell face may be ox a length which
ensures the largest anticipated amount of tape on the supply reel
does not urge the free end of the locking arm displacer to rotate
past the dwell face.
Stop 78 (of figure 1) is positioned to limit the clockwise
rotation of the follower arm to just past the point to which the
arm would be moved by rewinding of the longest anticipated tape
spliced onto the leader tape of the cassette. The stop 78 ensures
the follower arm is not rotated to a point whereat the free end of
the locking arm displacer rotates past the dwell face of the
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04~45-32 RDF
locking arm. Stop 78 also avoids an improper reset of the lock
actuation means for reasons which will be described hereinafter.
The enlarged locking tip 98 (seen in figure 7) of the locking
arm ensures there is no possibility of the locking tooth missing
the locking arm during forward feeding in the lock-up state. This
would otherwise be a possibility due to the fact the supply and
take-up reels float within the cassette. Similarly, abutment 140
(seen in figure 1) positioned in opposition to the locking arm
ensures the take-up reel is not translated such that the locking
tooth misses the locking arm during forward eeding in the lock-
up state.
Once the lock actuation means has been moved past the lock-
up point (i.e., once the locking arm has been displaced into the
path oE tooth 50 by reason of stop 11~ acting on the detent of the
locking arm displacer), it is necessary to reset the lock actuation
means to its disabled state before it is possible to again forward
feed the tape. Referring to figures 5 and 6, the reset means
comprise reset lever 120. As aforenoted, the reset lever is biased
against notched disks 130. The notched disks are a stack of
concentric disks having a height less than the height H (see figure
9) oE the head 124 of the reset lever. Prior to a resetting
operation, the disks are in a scrambled state such that their
notches 134 are not aligned with the head 124 of the reset lever.
In this statel the reset lever abuts the periphery of the stack of
notched disks as illustrated in figures 5 and 6; this is referred
to herein as the inoperative position of the reset lever. The
disks are manipulable by some means external of the cassette. If
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04445-32 RDF
the disks are manipulated to align the notch of each disk with the
head 124 of the reset lever 120, then the head of the reset lever
will snap into the aligned notches under the urging of torsion
spring 122; this is the reset position of the reset lever and is
illustrated in figure 13. As the head 124 of the reset lever
enters the notches of the disks, the reset lever rotates
counterclockwise on post 72 which results in cam 126 of the reset
lever camming the detent 102 o the locking arm displacer out of
the notch 112 in the follower arm. Once the detent clears stop 114
the locking arm displacer is freed to rotate counterclockwise under
the urging of torsion spring 106 to its rest position in abutment
with the reset lever. The locking arm 92 Eollows the locking arm
displacer due to t:he urging oE torsion spring 99 so that it
continues to rest against the locking arm displacer. Accordingly,
detent 102 will now abut the unnotched segment 116 of the arcuate
portion of the follower arm so that the lock actuation means is now
in its disabled state. The cassette with the reset lever in its
reset position and the lock actuation means disabled is illustrated
in figure 13.
The follower arm is stationary during a reset operation. This
is for the reason that the lock-up point is reached by building
layers of tape on the supply reel deflecting the follower arm,
consequently, the tape on the supply reel acts to prevent any
counterclockwise rotation of the Eollower arm due to the sliding
frictional engagement of the end of the detent with the unnotched
arcuate portion of the follower arm as the detent rotates
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04445 32 RDF
counterclockwise under the urging of torsion spring 106 to its rest
position.
As aforedescribed, the locking arm dlsplacer is in its rest
position when it abuts the reset lever. However, the rest position
of the locking arm displacer when the reset lever is in its reset
position is displaced in a counterclockwise direction from the rest
position of the locking arm displacer when the reset lever is in
its inoperative position. Accordingly, the dimensions of the
cassette may be chosen so that the reset rest position of the
locking arm displacer places the detent of the locking arm
displacer in a position which is displaced counterclockwise from
the counterclockwise position of the notch 114 of the follower arm
when the follower arm is stopped against stop 7g. Thus, if the
reset lever is not returned to its inoperative position, the lock
actuation means will have no trigger point. That is, there will
be no position of the follower arm which will cause the detent to
snap into notch 11~. Hence, the lock means cannnot be enabled.
The utility of this design feature will become apparent
hereinafter.
It is noted that the tape should be rewound to the lock-up
point beEore a resetting operation since otherwise a resetting
operation may not disable the lock actuation means.
In order to return the reset lever to its inoperative position
(so that the disabled lock acutation means will become enabled at
the trigger point), the camming disk 130a of the stack of notched
disks may be rotated so that camming surface 136 cams the head 124
of the reset lever out of the notches 134 in the remaining notched
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disks 130 whereupon the remaining notched disks may be again
scrambled so that their notches are no longer aligned with the head
of the reset lever; the camming disk 130a may then also be
scrambled.
The stack of notched disks function as a combination lock
since the angular position of the notches of the disks must be
known in order to allow the notches to be aligned with the head of
the reset lever. The details of construction of a suitable notched
disk arrangement functioning as a combination lock are described
in U.S. Patent No. 4,874,143 to Armstrong and Granzotto dated June
9, 1988, the disclosure of which is incorporated herein by
reference.
It is noted that, when the lock actuation means is enabled,
the stop 78 Eor the follower arm prevents the follower arm from
rotating the locking arm displacer clockwise sufficiently to result
in the cam of the reset lever camming detent 102 out of the notch
of the follower arm when the reset lever is in its inoperative
position.
The flag 108 (see figures 5 and 8) of the locking arm
displacer 100 underlies a window (not shown) in the housing of the
cassette. Flag 108 will move under the window in the cassette
housing when the locking arm displacer rotates. Accordingly,
diEferent portions of the surface of the flag 108 will be centered
under the window depending on the angular position of the locking
arm displacer. Consequently, the flag 108 may be divided into
three colour coded zones to indicate different states for the
cassette, as follows. The locking arm displacer has been rotated
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04~45-32 RDF
toward the limit of its clockwise rotation when the cassette is in
the lock-up state. Accordingly, the zone 108a of the flag at the
counterclockwise end of the flag, may indicate the cassette is in
the lock-up state. A middle zone 108b of the flag may indicate the
locking arm displacer is at or near its rest position against the
reset lever and the reset lever is in its inoperative position
This middle zone accordingly indicates the tape of the cassette may
be forward fed or rewound. When the reset lever is in its reset
position, the locking arm displacer is resting against the reset
lever (since the detent has been cammed out of the notch in the
follower arm) and so is at the limit of its counterclockwise
rotation. ~ccordi~gly, a third zone 108c at the clockwise end of
the flag indicates that the lock actuation means is disabled and
the reset lever is in its reset position. The purpose for such an
indication will become clear hereinafter.
It will now be apparent that the cassette, when the lock
actuation means is in a disabled state and the reset lever is in
its inoperative position, allows the tape to be Eorward fed from
beginning to end only once since thereafter the lock actuation
means is enabled which inhibits forward feeding after a pre-
selected amount of tape has been rewound onto the supply reel (such
that the cassette is in the lock-up state). The cassette does,
however, allow limited replay of portions of the tape. By way of
example, the cassette may be constructed so that the trigger point
is at the point where 75 minutes (SP mode) of the tape has been
wound onto the take-up reel and the lock-up point is at the point
where 75 minutes (SP mode) of the tape has been wound onto the
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04445-32 RDF
supply reel (after the lock actuation means has been enabled).
Accordingly, the first 75 minutes of the tape up to the trigger
point may be replayed an indefinite number of times so long as the
75 minute point is not passed. Also, after the trigger point has
been reached, the last 75 minutes of the tape may be replayed an
indefinite number of times. However, as soon as the lock-up point
is passed on rewinding, the tape will lock up if an attempt is made
thereafter to forward feed the tape. Of course once the lock-up
point has been passed, it is still possible to rewind the tape.
A tape machine is typically designed to stop rewinding at the
beginning of the magnetic tape. IE this point is overshot such
that some of the leader tape is wound oEE the take-up reel, some
machines will automatically forward feed back to the beginning of
the magnetic tape and will not allow the cassette to be ejected
until this has been accomplished. In order for the cassette of
this invention to function with such tape machines in the worst
case scenario, the cassette must be able to forward feed
sufficiently to take up all of the leader tape when it is in the
lock-up state. Accordingly, the cassette is manufactured with
approximately 5.75 inches of leader tape on the take-up reel and
is configured to permit up to about 1 3/4 forward feed revolutions
of the take-up reel while the cassette is in the lock-up state, as
follows. Referring to figure l, snaps 28a and 28b of the inner
locking member of the locking means are spaced more widely than the
other snaps, consequently, the inner locking member always has a
fixed orientation on the take-up reel 14. This orientation is such
that the point of connection 17 of the tape 16 to the take-up reel
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)J 7
04445-32 RDF
is displaced slightly in a counterclockwise direction from pawl 36.
Furthermore, since tooth 50 of the outer locking member is
positioned ninety degrees in a counterclockwise direction from
notch A4, the notch 44 is in a pre-determined position when the
tooth 50 rests on the leaf spring 64 duriny rewinding. The
position of notch 44 on rewinding is such that when the last layer
of tape has been wound off the take-up reel and rewinding is
complete, the pawl 36 is displaced slightly in a clockwise
direction from the position of the notch 44, as is illustrated in
figure 1. By virtue of this arrangement, the take-up reel is free
to rotate approximately three quarters of a clockwise revolution
while the locking tooth rotates with the take-up reel from its rest
positlon on the leaE sprlng lnto abutment with the locking arm and
is free to rotate approxlmately a just under a further one
clockwise revolution while the pawl rotates into registration with
the notch 44.
If it were desired to minimize any forward feed rotation of
the take-up reel while the cassette is ln the lock-up state, this
may be accomplished by repositioning the leaf spring 64 and
increasing the number of notches 44 in the outer locking member 40,
as wlll be apparent to one skilled in the art.
The present invention has utility in the video rental
industry. If a cassette as aforedescribed has a tape recorded with
a movie, the cassette may be rented in a rewound state with the
lock actuation means disabled. The rental allows the renter one
complete viewing of the movie with the ability to review portions
of the movie and the abllity to rewlnd the tape prlor to its
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~2
04445-32 RDF
return. The rental outlet may have access to the combination for
the notched disks oE the cassette so that the lock actuation means
may again be disabled whereupon the cassette is once more ready for
rental.
Further, if it is desired to sell a rental tape, the notches
of the disk stack may be aligned with the reset lever head so that
the reset lever snaps to its reset position and the cassette left
in that condition so that, as aforedescribed, the lock actuation
means cannot be enabled. Consequently, there will be no
restriction on the forward feeding oE tape in the cassette which
is sold.
The Eollower arm could be modified such that it included only
one wheel along its length which wheel was biased into abutment
with either the outer layer of tape of the supply reel or the outer
layer of tape of the take-up reel. However, two wheels for the
follower arm are preferred as this is believed to be a more tamper
proof construction. Other variations within the spirit of this
invention will be apparent to those skilled in the art.
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