Patent GB-696650-A (GB)
Title: Improvements relating to magnetic sound transducing apparatus
Inventor: DUTTON GILBERT FARADAY
IPC: G11B15/44
Filed: 1950-11-22
Abstract: 696,650. Magnetic recording and reproducing apparatus. ELECTRIC & MUSICAL INDUSTRIES, Ltd. Nov. 22, 1951 [Nov. 22, 1950]. No. 28497/50. Class 40 (ii) In a magnetic tape transducing apparatus, the means 13 for controlling the slow speed drive for recording and reproducing is interlocked with the high speed spooling control 13a so that each control can only be moved to an operative position when the other is in the inoperative position. The control 13 comprises a setting knob, associated with scale indications corresponding to " Stop," " Record," "Replay" and "Monitor" settings, and has a shaft 47 provided with an aperture plate 51, Fig. 4, which engages a pin 68 on a sliding bar 66, said bar having a similar pin 69 engaging a plate 58a on the shaft 48 of the spooling control 13a. The bar 66 is moved to the right, as viewed in Fig. 4, by the movement of either of the controls 13 or 13a from the "Stop" position. If control 13 is moved from the "Stop" position, the pin 69 is drawn into a notch 65 in plate 58a and thereby locks control 13a, while when control 13a is similarly moved, the pin 68 is pushed into a notch 53 in plate 51 to lock control 13. Movement of the bar 66 to the right also serves to move bars 104, 105 which release band brakes 170, 171, which bear on drums 134, 132 mounted on the spool shafts 7, 8, Fig. 7. Mounted on bar 66 is an arm 95, Fig. 4, with a projecting corner 96 which engages a notch 97 or 98 in a member 94 on a shaft 93 which is rotated to one or other of two positions by a lever 14, Fig. 1, according to the speed of rotation required of the driving motor. An arm 98a on the shaft 93 is coupled to means for altering the speed of the motor. A shaft 121, Figs. 6 and 7, is driven by a belt from the motor, and during spooling operations one or other of spring-loaded jockey pulleys 138, 139, according to the direction of spooling required, is pressed respectively with drums 131 or 133, and pulley 130, by a lever 144 operated by the spooling control 13a. A linkage 151, 153 serves to withdraw one or other of spring-loaded brake arms 156, 157 so that only the trailing spool is braked. During a transducing or monitoring operation a spring- loaded jockey wheel 163, Fig. 4, is brought into contact with a hub 162 on the shaft 121 and with a drum 135, Fig. 7, frictionally coupled to the drum 134 on the shaft 8 carrying the take-up spool. The speed of the record tape past the magnetic heads 32, 33 is controlled by a capstan shaft 115, Figs. 3 and 4, against which the tape is pressed by a pulley 44 during a transducing operation under the influence of a linkage 73, 75, 77, 79 connected to a further aperture plate 70 on the shaft 47 of control 13. This same linkage serves to press the tape against the transducers by means of an arm 82, Fig. 4, on a shaft 83 which carries an arm 39, Fig. 3, on which is mounted a guide pin 41 and a pad 43 to press the tape against a guide 38. A pointer 26, Fig. 1, in a window 27 indicates (by means not described) the amount of tape on the spools. Specifications 672,981, 693,685 and 693,695 are referred to.