Note: Descriptions are shown in the official language in which they were submitted.
RCA 68,900
~07GZ55
The present invention relates to disc record
player systems, and more particularly relates to a lid
interlock apparatus for (l) preventing openlng of the
player lid during playback, and ~2) braking the turntable
when the lid is opened while the turntable,is rota~ing.
In certain video disc systems, video information -
is recorded by means of geometric variations in the bottom
of a smooth spiral groove on the surface of a disc record.
The disc record surface includes a coating of conductive
material which is preferabIy covered with a thin deposit
of dielectric material. A signal pickup, supported at one
end of a pickup arm, engages the spiral groove and includes
a conductive electrode which establishes a capacitance with ' ,'
the conductive coating and the dielectric ~eposit of the '
disc record. When the disc record is rotated, the electrode- '
disc capacitance varies in response to the geometric
variations in the bottom of the spiral groove passing
beneath the signal pickup. The capacitance variations are
converted to electrical signal variations by a suitable
signal processing clrcuitry coupled to the pickup electrode.
The output signal of the signal processing circuitry may
be coupled, to a conventional television receiver for ,
reproduction. The pickup arm is mounted within a si~nal
pickup housing of the playback system. A system of the
aforementioned type is described in detail in U.S. Patent
No. 3,842,194, issued on October 15, 1974 to Jon K. Clemens.
Video disc systems of the aforementioned type
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1 generally utilize disc records having groove denslties in
the order of four to eight thousand groove convolutions
per inch. A typical video disc record of this type may
have a groov~ convolution spacing in the order of 3.5 microns.
The fragile walls of relatively narrow grooves of the disc
record cannot be dependably relied upon to pull the pickup
arm assembly, around the pickup arm pivot support, across
the entire recorded surface of the disc record. Also, in
video disc systems utilizing the variable capacitor concept,
1~ it is desirable for accurate reproduction of the prerecorded -
signals that the signal pickup electrode maintain a sub-
stantially constant attitude in the spiral groove. There-
fore, a radial feed drive mechanism is provided for
traversing the signal pickup housing in proper time re].ation.
lS ship with ~the radial motion of the signal pickup t~p engaged
in the spiral groove so as to continuously maintain the
longitudinal axis of the pickup arm substantially tangential
to the spiral groove at the point of engagement when the ;
player is i~ a playback mode. Reference may be made to U.S.
Patent No. 3,870,835 (Stave), issued 3-11-75,entitled
"Stylus Control Apparatus For A Video Disa Record
Player", for an illustration of a suitable
radial feed drive mechanism for providiny the indicated
radial mot1on.
Further, in the aforesaid video disc systems,
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adequate bandwidth for monochrome and color display is
obtained by rotating the disc at a speed substantially
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higher (e~.g.,~450 rpm) than the conventional audio playback
speeds (e.g., 33 and one-third rpm).
Additionally, in the above-mentioned video disc
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1 systems, groove engaging and low mass requirements of a
signal pickup assembly result in a plckup arm unit which is
extremely fragile (e.g., signal pickup width 2 microns,
signal pickup depth 5 microns, signal pickup electrode
width 2 microns, and signal pickup electrode depth 0.2
microns).
In the playback systems of the aforementioned type
the following considerations may be encountered~ It
is desirable to prevent opening of the lid when the signal
pickup housing is in the playback mode in order to protect
the fragile signal pickup assembly of the player.
It is also advantageous to brake the turntable
when the lid i5 opened while the turntable is rotating at
relatively high speed (e.g., 450 rpm) in order to reduce
safety hazard to the player user.
It may be preferable to preclude opening
of the lid until the signal pickup housing has cleared the
disc record so that the record just played may be removed
for changing side, or placing a new disc record on the
turntable without hindrance.
Pursuant to an illustrative embodiment of the
present invention, a lid is pivoted to the base of a disc
record player for movement between a closed position and
an open position. A lid latch member .is mounted
Eor securely holding the li.d in the closed position,
and releasing the lid in responsa to manipulation of
a lid release lever. Means operative between a
first condition decoupling, and a second condition
intercoupl1ng, the release lever and the latch member is
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1 provided. Means interconnecting the operative means and
a signal pickup housing of the player is effective for
aisposing the operative means into the first
condition when the housing is in a playback mode whereat
manipulation of the release lever is ineffective to release
the lid, and into the second condition when the housing
is in a standby mode whereat the latch member responsive
to manipulation of the lever releases the lid, if the lid
were closed.
Pursuant to a further feature of the invention,
a turntable brake mechanism is provided for braking the
turntable when the lid is opened while the turntable is
rotating.
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Objects, features, and advantages of the present
invention will be more fully understood from the following
detailed description of the preferred embod~ment, t~e
appended c1a1ms, and the accompanying drawings in whic~:
FIGURE l is a plan view of a video disc player
incorporating an illustrati.ve embodiment of a lid interlock
apparatus according to the present invention, the lid of
the player is shown in an open position for clarity;
FIGURE 2 is a side view of the video disc player
o~ FIGURE l
FIGURE 3 is a partially cut-away, perspective
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view of the~lid interlock apparatus suitable for use with
the player of FIGURES l and 2; ~ ;;
FIGURE 4 is a front view of a portion of the lid
interlock apparatus of FIGURE 3;
FIGURE 5 is a partially cut-away, sectioned side
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1 view of the lid interlock apparatus along the line X-X in
FIGURE 4i
FI~URE 6 diagrammatically'illustrates a turntable
brake mechanism suitable for use with the lid interlock
apparatus of FIGURES 3, 4, and 5; and
FIGURE 7 iS a partially cut-away, perspective
view of a modified lid interlock apparatus according to
another embodiment of the present invention.
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~Referring to the drawings, wherein like reference ,~'
numerals designate similar elements in the various views,
in FIGURES l and 2 a video disc player is~shown having a
base lO. A lid ll is pivoted to the base lO for movement
between a closed position and an open position. The player
is suitable for use in a video disc system such as disclosed
in the aforementioned Clemens patent. A turntable 12 is
rotatably mounted on the base lO. The upper surface of the
turntable 12 is adapted to support a video disc record 13.
Video informat1on is recorded by means of geometrical
variations 1n;the bottom of a smooth spiral groove 14 on the
substrate Oe the disc record 13. The disc record 13 sur~ace
includes a conductive coatiny which is preferably covered ',
with a thin deposit of dielectric material. A signal pickup
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15, supported at one end of a conductive pickup arm 16,
engages the spiral groove 14 and includes a conductive
electrode (not shownj which, ~,ogèther with the conductive
coating and the dieleatr1c deposit, form a capacitor. When
relative motion is established between the signal pickup 15
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and the disc record 13j an edge of the electrode included ,
in the signal pickupj~ while riding in the~spiral groove 14,
.,
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1 serves as an electrode of a capacitor varying due to the
geometric variations in the bottom of a smooth spiral groove
passing beneath. The other end oE the plckup ~rm 16 is
flexibly supported by a pickup arm support carried by a
signal pickup housing 17.
As indicated before, a radial feed drive mechanism
18 traverses the pickup arm support mounted in signal pickup
housing 17~in proper time relationship with the radial
motion of the slgnal pickup 15 tip engaged in the spiral
groove 14 so as to continuously maintain the longitudinal
axis of the pickup arm substantially tangential to the
spiral groove at th~ point of engagement. A slot 28 is
provided in the base 10 for accommodating the radial motion
of the housing 17. Reference may be made to the afore-
menti.oned Stave patent (U.S. Patent No. 3,870,835)
for an illustration of a suitable feed drive mechanism for
providing the indicated radial motion.
During playback, the pickup arm 16 passes through
an opening 19 in the bottom wall of the housing to allow
the signal pickup L5 to ride in the spiral groove 14. A ;
pivotally mounted bracket 20 lifts the free end of the
pickup arm 16 to disengage the siynal pickup 15 from the
spiral groove 14 when the player is inoperativeO
A plurality of push buttons 21, 22, 23, 24,
2S 25, and 26 are provided along the front panel 27 for,
respectively, effecting the following functions: start,
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pause, rejèct, fast forward, reverse, and lid release. ;~
A lip 29 lS fastened to the lid 11 for entry into
an opening 30 provided in the base 10 in order to engage a ~
30~ latch member of a lid interlock apparatus 31 to be described ;
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1 subsequently. A plunger/of a turntable brake mechanism 32
is reciprocably mounted in the base lO for cooperation with
the lid ll in the manner also to be described subsequently.
Reference will now be made to FIGURES 3, 4, and 5.
FIGURE 3 is a partially cut-away, perspective view of the
lid interlock apparatus 31. FIGURES 4 and 5 are, respec-
tively, th front view and a partially sectioned side view
of a portion of the lid interlock apparatus of FIGURE 3.
A latch member comprises a plate 33 pivotally
mounted on the base lO for movement between (l) a protruding
position, and (2) a retracted position. A first tab 34
is secured to the plate 33 for (a) engagement with an
aperture 35 provided in the lip ~9 of the lid ll when the
plate 33 is in the protruding position, and (b) releasing
the lip when the plate is in retracted position, if the
lid is closed. A wire spring 36 is inserted into an opening
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37 provided in a tab 38 fastened to the plate 33 in a
manner that biases the plate in the protruding position.
The first tab 34 has a slanting top surface in order to
facilitate gradual shi~ting of the plate 33 to the retracted
position by the lip 29 as the lip is inserted into the :
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opening 30 provided in the base lO. The wire spring 36
pushes the first tab 34 into the aperture 35 disposed in
the lip 29 thereby securely holding the lid 1l to the base
lO. A second tab 39 is secured to the plate 33 ~or
engagement~with one end of a slide member 40 reciprocably
mounted to a bracket 41 attached to the base~lO. Elongated
slots 42 and 43 are provided in the slide 40 for cooperation
with pins 44 and 45 fastened to the bracket 41 thereby
permitting reciprocating movement of the slide with respect
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1 to the bracket. The second tab 39 has a slanting bottom
surface in order to facilitate gradual movement of the plate
33 against the sprlng 36 to the retracted position by the
one end of the slide 40 as the slide ls pushed upward.
The slid'e 40 has a neck portion 46 at the second
end forming a shoulder portion 47 at the second end of the
slide. A lid release lever 48, carrying the push button 26,
is pivotally mounted on a frame 49 attached to the base l0.
An open-ended slot 50 is pro~ided at one end of the lid
release lever 48 for freely receiving the~neck portion 46
of the slide 40. When the push button 26 is depressed,
the lid release lever 48 engages the shoulder portion ~7
of the sl'ide pushing the slide upward. The upward mot~on
of the slide causes the plate 33 to retract thereb~
releasing the lid ll, if the lid were closed. Means are '; ;
provided for biasing the lid ll in the open position and ~'
the push button 26 in an elevated position.
A cam 51 is pivotally mounted on the bracket 41
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by a pin 52 attached to the bracket on the side opposite
of the slide 40. A retainer 52' positions the cam 51 on the ,,
pin 52. The cam Sl is movable between (l) a'first condition `"i"' ""'
decoupling, and (2) a second condition intercoupling, the
release lever 48 and the latch member plate 33. Orientation
of tho cam 51 in the first condition renders the lid
~5 release lever 48 immovable because a tounge portion 53 ~
of the cam~blocks the manipulation of the lever. Orientation ~; ',
of the cam'5L in the second condition (as illustrated in ' ,
FIGURES 3j 4, and 5) fre~s the manipulation'of the lever 48. -,~
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Means 54 are provided for interconnecting the
cam 51 and the housing 17. The radial feed drive 18 drives
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1 the housing 17 between a standby mode and the playback mode.
The interconnecting means 54 is eEfective for moving the
cam 51 (a~ into the first condition when the housing 17 is in
the playback mode whereat manipulation of the release lever
48 is ineffective to release the lid 11, and (b) into the
second condition when the housing is in the off the record
disc standby mode (such as shown in FIGURE 1) whereat the
latch member responsive to manipulation of the lever releases
the lid, if the lid were closed.
Illustratively, the interconnecting means 54
comprises a first hub 55 pivotally mounted in the base 10.
A pin 56 is secured to the hub 55 for engagement with a
downwardly depending tab 57 coupled to the housing 17.
When the housing 17 moves from the playback mode to the
standby mode, the tab 57 engages the pin 56 and rotates
the hub 55 in clockwise direction when viewed from the ;:
top. A second hub 58 is mounted in the base for rotation
with the~.first hub 55. A pin 59 is secured to the second
hub 58. A cord 60 interconnects the cam 51 and the pin 59
attached to the hub 58. A pulley 61 is mounted on a
bracket attached to the frame 49 of the base 10. The
pulley 61 guides the cord 60 such that clockwise rotation
of the hubs (55 and 58), as the housing 17 moves from the
playback mode to the standby mode, causes the cam 51 to move
to the second condition, thereby freeing the lid release .
lever 48 to operate the latch member for releasing the ~ :
lid 11.
A wire spring 62 is provided for biasing the cam
in the first condition, whereby when the housing 17 is in
the playback mode manipulation of the lid release lever 48
is ineffective to release the lid 11.
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1 A safety spring 63 may be inserted in the cord 60
to prevent damage in the event of mechanical failure, such
as jamming.
An opening 64 is provided in the base lO, as shown
in FIGURE 5j for the purpose of releasing the lid ll by
pushing the,slide 40 upward, irrespective of the position
of the cam Sl. 32
The turntable bxake mechanism/w1ll now be explained
by reference to FIGURE 6. A plunger 65 is reciprocably
mounted in the base lO for movement between (l) a first
position when the lid ll is released open, and (2) a second ;'
position when the lid is closed, in response to the lid
movement. A spring 66 is inserted between a retainer 70,
attached to the plunger 65, and the base lO~for biasing
the plunger in the first position. A frict~on pad 67 ~s ~,
secured to the other end of a bracket 68 attached to t~e
plunger 65(for engagement with the underside of the turn~
table 12 when the plunger is in the first position effecting
braking o$'the turntable when the lid ll is opened while
the turntable is rotating. A slot 69 is cut into the
base lO for permitting reciprocal motion of the bracket 68.
The movement of the plunger 65, when the lid ll
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is opened,,may be advantageously utilized to cut off power ,;
to the turntable drive motion (not shown), thereby further
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reducing the safety hazard. '
Thus, the described lid interlock a~arat1~ maY be
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used to (l) prevent opening of the lid during playback, or
~2) brake thè turntable when the lid is opened while the
turntable is rotating at a relatively high speed or both. '' ''
~ ~FIGURE 7 is a partially cut-away, perspective
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RCA 68 ,900
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1 view of a modified interloc]c apparatus according to another
embodiment of the present invention. In the FIGURE 7
embodiment the cam 51 is mounted on the reciprocating
slide 40 instead of on the fixed bracket 41. The cam 51
ls positionable between (1) a first condition intercoupling,
and (2) a second condition decoupling (as illustrated in
FIGURE 7), the release lever 48 and the slide 40. When the
cam 51 is in the second condition, the latch member structure
does not obstruct movement of the lever 48 as the shoulder
portions 47 of the slide 40 do not engage the lever through-
out the range of movement of khe lever (in contradistinction
to arrangement of FIGURES 3, 4, and 5). The reason for
the FIGURE 7~arrangement is that it protects the lid inter-
lock apparatus from damage in the event of accidental
pushing of the lever 48 when the housing 17 is in the play-
back mode as the lever is now fxee to move. Interconnecting
means is efEective for moving the cam 51 ~a) into the first
condition when the housing 17 is in the standby mode whereat .
the latch member plate 33 responsive ko the movement of the
slide member.40 caused by manipulation of the lever 48, via
the cam, releases the lid 11, and (b) into the second
condition~when the housing i.s in the playback mode whereat
manipulation of the release lever is ineffective to release
the lid, i~f the lid were closed.
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