Patent GB-1455449-A (GB)
Title: Video disc player
IPC: G11B17/035
Filed: 1973-12-10
Abstract: 1455449 Playback of video disc record SANYO ELECTRIC CO Ltd 10 Dec 1973 [8 Dec 1972] 57227/73 Heading G5R An arrangement for playing back video information recorded in a groove of a foil type disc record which is stored in its jacket comprises a jacket receiving, locking and ejecting unit, a disc feed unit for feeding the record from its jacket to a stationary table, a chuck unit for engaging the disc with a rotatable spindle extending through the table, a scanner movement control unit for controlling the movement of a stylus for reproducing the information and a mode selector for selecting a normal or still picture reproducing mode. Substantially all the operations are controlled by a manually rotated cam member. The record jacket, Fig. 1, comprises upper and lower plates 2a, 2b joined by a spacer 2c of substantially U-shaped configuration to define a space 2 for the disc 4. To assist removal of the record the jacket is provided with a pair of spaced holes 10 for anchoring the jacket in the machine, the lower plate 2b is formed adjacent the jacket opening 1a with a portion 3 which hinges about a line of weakness 5 formed across the plate and the upper plate is formed with notches 9 through which fingers in the machine engage and open the hinged part 3 of the lower plate. A band of magnetic material 8 is provided on the inner surface of the hinged portion adjacent the jacket opening which co-operates with a band of ferrous material on the upper plate to hold the hinged part closed when the bands are engaged. The jacket locking and ejecting unit, Fig. 2, receives the jacket between guides 22 and between lower plate 23 and an upper plate (not shown). The jacket displaces biasing devices including sliders 25 as it is pushed into a position in which apertures in the jacket are engaged by locking pins 30 which are mounted on a pair of swing bars 31 biased by spring elements (not shown) into the lock position. The bars are joined by a strip member 32 with upward extending arms 33 which are pivotally supported by the guides and a slide member 36 is formed with a projection 35 which engages one of the arms, when the member is displaced by counterclockwise rotation of the manually rotatable cam member 44, to swing the bars and the pins to a non-locking position so that the jacket is ejected by the biased devices including sliders 25. The disc feed unit, Fig. 5, includes an opener 50 for opening part 3 of the jacket 1 by means of spring-loaded finger members 54a as the jacket is inserted into the unit. The disc record 4 is thus exposed and extends into a cut-out portion 61c of a transfer roller 61 so that as the roller, which is covered with, e.g. soft rubber, is rotated by clockwise rotation of the rotatable cam member, the record is drawn out of the anchored jacket and transported via guide 62 to stationary table A where when the record is completely transferred the portion 61c of the roller lies above the table with the roller clear of the record rotation path. When reproduction is completed reverse rotation of the cam member moves the disc back into the jacket, the rotation of the cam member triggering the ejection of the jacket when the disc is fully replaced therein. The drive coupling for the roller is described with reference to Fig. 3 (not shown). The chuck unit, Fig. 6, includes a chuck member 80 which centres the record disc for rotation after the disc has been positioned on table A by side guide members and a step member, the chuck member has a rotatable block portion 82 which descends during clockwise rotation of the rotatable cam member 44a to engage the disc with disc mount 98 secured to the drive spindle 81. The projection 82a of the block portion 82 engages in the centre hole of the record and in the recess 98 of the disc mount. The block portion includes an annular magnet 109 to hold the portion in engagement with the disc mount, which must be of magnetic material, and a rubber member 110 for preventing slip. The seaming control unit, Fig. 4, includes a guide rail 123 along which a carriage 121 carrying stylus 122 is moved by means of a cord drive 134. The drive is coupled via a clutch unit to the turntable drive and magnets 130, 131 carried by the carriage co-operate with reed limit switches 128, 129 in control of the drive. The guide rail is pivotable to raise and lower the stylus, the lowering action being under the control of a play button, a damping device and a safety device for preventing lowering in the absence of a record. The mode control includes play, stop and still buttons for controlling operation. Operation of the play button acts to lower the stylus and acts on the clutch to transmit drive to the carriage. Operation of the still button whilst the play button is still depressed disconnects the clutch so that a still picture is produced and operation of the stop button returns the play button to its initial position. A solenoid member is provided which is actuated when the carriage reaches its innermost position or when the manually rotatable cam member is moved during playback. This acts to return the play button to its initial position whereby the stylus is lifted and reverses the direction of drive to the carriage so that this returns to its start position at which the outer reed switch is actuated to de-energize the solenoid. A safety circuit is also provided to operate the solenoid to return the playback button to its initial position if a photo-sensitive element detects that a disc is not present on the table.