GB531492A - Improvements in or relating to sound recording and reproducing devices - Google Patents

Abstract

531,492. Multi-track sound film apparatus. STEVENS, A. H. (Film Recording Corporation). July 24, 1939, No. 21472. [Class 40 (ii)] A multiple track sound film apparatus is provided with means for indicating both the lateral displacement of the recording or reproducing head determining a particular track and the travel cf the film determining the position of the head along the said track. In the apparatus shown, the film 11, Figs. 1 and 2 is driven by a sprocket wheel 6 on a shaft 4 fitted with a fly-wheel 5. The film is taken from a reel on bracket 15a to a reel on a bracket 14a. Normally, the take-up reel is driven by a belt 13a from a pulley 12a on the shaft 4. For winding the film back, the other reel is driven by a belt 16a from a pulley on the shaft or a roller 17a which is then brought by a lever 18a into frictional engagement with the fly-wheel 5. The film in its normal travel first passes through a dust removing device 13, then between guide rollers 12, and over the sprocket wheel 6, against which it is held by a pair of rollers 10. The rollers 10 are carried by a lever 9 normally held down by a spring 16 but capable of being lifted by means of a cam 14 with a handle 15. The length of travel of the film is indicated by a pointer 80 on a dial 75, the pointer being frictionally attached to a shaft 71, Fig. 6, geared by worm gear 73, 70 to a vertical spindle 61 itself geared by worm gear 65, 57 to the shaft 4. The recording head or the reproducing head 23 is mounted between horizontal pivots 22 on a carriage 20, which is mounted in a dove-tailed groove 18 allowing for adjustment transversely of the film. For this adjustment, a lever 33 is provided extending below the base 1 of the apparatus. The lever 33 is attached to a short vertical spindle 34 having a conical shape to take up wear. To the other end of the spindle is attached a short lever 36 with a spring 37 gripping between them a pin 38 on the carriage 20. The end of the lever 33 is bent up and fitted with a knob 40 carrying a spring pressed pin 41 co-operating with a set of holes 43 to hold the lever in its set position, the holes being marked with indicia indicating the corresponding longitudinal track of the film to which the recording or reproducing head is thus set. To lower and raise the head to engage and disengage the stylus from the film, the head is fitted with a finger 31 resting in a groove on an eccentric 29 adapted to be set by a handle 30. In a modification, the carriage of the recording or reproducing head is adjusted transversely by a screw and nut device set by a handle in relation to a dial.