Patent GB-471713-A (GB)
Title: Improvements in or pertaining to sound film apparatus
IPC: F22B35/10
Filed: 1936-12-04
Abstract: 471,713. Sound - - film apparatus. PINTSCH AKT.-GES., J., and MIHALY, D. VON. Dec. 4, 1936, No. 33374. Convention date, Dec. 6, 1935. [Class 40 (ii)] [Also in Group XX] Relates to apparatus for recording, copying, or reproducing a photographic sound record on an endless film strip, the record being in the form of a continuous track extending a number of times round the band parallel to the edges thereof, the record shifting at intervals without interruption from one track to the next and the beam of light that effects the recording, the copying or the reproduction being shifted intermittently transversely to the film. According to the invention, when the apparatus is initially put into operation, the optical means that projects the beam of light on the film is arranged so that the beam of light is located outside the utilizable width of the film and is brought into alignment with the first record track as the result of a subsequent transverse shifting operation. The arrangement is also preferably such that, after the recording or scanning of the last sound track of the film strip has been completed, the beam of light is shifted a further distance transversely to the film so that it is again outside the utilizable width of the film. The Figure shows a recording apparatus of somewhat similar construction to that described in Specification 453,890 in which an endless film 1 is fed around a drum 2 within which is a vertically movable frame 3 carrying the recording lamp 4, a condenser 5 and a screen 7 which is provided with a slit 6 and to which is fastened a mirror 8 that directs the light on to the film through the slit. The frame 3 rests by means of a knife edge 9 on the short arm 10 of a pivoted lever, the long arm 11 of which is provided with a toothed segment 12, the teeth of which are engaged by the spring-controlled pawl-shaped armature 13 of the electromagnet 14 and also by another spring-controlled pawl 16. The film is provided with a notch 18 adapted to co-operate once per revolution of the film with a spring roller 19 rotatable together with contact 20 about the point 21. Contact 20 is connected through battery 22 with one side of the electromagnet, whilst the counter contact 23 is connected through a hand switch 24 with the other side of the magnet. A signal lamp 25 in proximity to the recording microphone is connected in parallel with the switch 24, whilst a second signal lamp 26, also in proximity to the microphone, is connected in parallel with the electromagnet 14. The segment 12, which has two teeth more than there are sound tracks to be recorded on the film, is adjusted so that, when it is in its highest position, the beam of light passing through the slit 6 impinges on the perforated portion of the film outside the useful width thereof. The apparatus is started with the switch 24 open so that the beam of light travels constantly along the perforated portion of the film until the film has attained its proper velocity when the switch is closed shortly after the passing of the roller 19 by the notch 18 and the lamp 25 is lit up so as to indicate that recording is to commence within a predetermined time. On the next engagement of the roller 19 with the notch 18, the electromagnet 14 is energized and the armature 13 depresses the segment 12 by one tooth so as to raise the frame 3 and the optical means carried thereby by the width of a sound track. At the same time, the lamp 26 is lit up so as to indicate that recording has begun. On the energization of magnet 14 following the completion of the recording of the last sound track, pawl 13 engages the topmost tooth of the segment 12 and thereby raises the frame 3 again by the width of a sound track so that the beam of light passing through slit 6 now impinges on the upper perforated portion of the film. According to a modification, Fig. 2 (not shown), an un-notched film is inserted in the apparatus and a notching device controlled by a solenoid in circuit with a hand switch is provided immediately in front of the roller 19 so that on closing the switch when recording is to begin, a notch is formed in the film which is immediately engaged by the roller 19 to effect energization of the magnet 14. The application of this modification to copying apparatus constructed and arranged as described in Specification 449,633, [Group XX], is also described, Fig. 3 (not shown). In this case, the primary film is provided with a notch in proximity to the beginning of the sound track thereon and adapted to be engaged by a roller in circuit with the solenoid of the notching device so that a notch is cut in the edge of the endless secondary film and this notch is engaged by a roller in circuit with the magnet of the shifting device to move the beam of light laterally on to the first track of the secondary film at the instant at which the commencement of the sound record on the primary film comes within its range.