Patent GB-1186593-A (GB)
Title: Sound Reproducing System
IPC: G11B7/00
Filed: 1967-05-02
Abstract: 1,186,593. Sound-only film reproducing apparatus. PANOPIX RESEARCH Inc. 2 May, 1967 [4 May,. 1966], No. 20388/67. Heading G5R. A sound-reproducing system comprises an elongated film having a plurality of parallel, optically-recorded sound tracks extending along it, transport means including a rotatable capstan for moving the film in either direction along a predetermined path, two optically-sensitive detecting means for the sound. track disposed one on each side of the capstan and adjacent the path, with each detecting means opposite one of the sound tracks,. only one of the detecting means-namely, that one which is adjacent the portion of film approaching the capstanbeing operative at any one time, and stepping means for relatively moving the detecting means and the transport means and film in a direction transverse to the path for positioning each of the detecting means opposite another of the sound tracks. Playback.-Film 16 carrying as many as 38 optically recorded sound tracks 40, Fig. 2, is disposed on a reel 14 within a cartridge housing 12, Fig. 1, located on a platform 2. The film extends around an idler roller 18 and through an opening 20, and passes between friction rollers 26, between parts of an optical demodulator 28, and between a pressure roller 32 and a capstan drum 30. Its path to a take-up reel 38 is through similar apparatus. Capstan drum 30 and the shafts of reels 14 and 38 are all driven by a motor 42. During transit from left to right, one track on the film is sensed by de-modulator 28 only (where the film is taut). At the end of the track a signal means 50, Fig. 2, on the film is detected by a sensor 54. This sensing initiates reversal of motor 42, deactivation of demodulator 28 and activation of demodulator 34, and operation of an escapement 80. The latter serves to permit subplatforms 58, each carrying one of the demodulators, to rise under the influence of compression springs 66 a distance equal to one tooth 78 of a ratchet bar 76, which is also equal to the inter-track spacing distance. The next adjacent track (recorded in the opposite direction) is then played back automatically during transit from right to left. Re-setting.-The uppermost sound track is located so that it is reproduced by transit of the film from right to left. When this run is completed,. the passage of signal 50 past one of the sensors 52 or 54 on this. occasion does not effect actuation of escapement 80 or reversal of motor 42; instead, the motor continues to run in the same direction to wind the film 16 wholly into the cartridge 12; at thesame time a clutch is operated to connect the motor to a winch 82 which, by means of a cord 84, led over pulleys 86, 88 and 90, and anchored at 92, draws the sub-platforms 58 down to their lowest positions. In a modification, not illustrated, the demodulators 28, 34 are not horizontally aligned but are separated vertically by a distance equal to the inter-track spacing. In this case the ratchet teeth 78 are twice as large and the escapement 80 is operated only on alternate reversals of the motor 42. Manual means may be provided to actuate escapement 80 for selection of a desired sound track.