GB441973A - Improvements in apparatus for protection against fire in cinematograph projection rooms - Google Patents

Abstract

441,973. Control systems for incandescent lamps. SAUVA, L., and VICINI, R., 16, Rue Juramy, Marseilles, France. May 8, 1935, No. 13602. [Class 38 (iv)] [See also Groups XXXVII and XX] Emergency systems. - A centrifugally-operated switch 26 which cuts out circuits and causes the operation of other safety devices in a cinema projection room when the film breaks or the motor driving it stops, comprises balls 33 which are normally held pressed by centrifugal force against the rim 32 of a pulley driven by the film 17 but which assume the position shown in Fig. 2 when the pulley stops, the two top balls closing a circuit between a metal ring 30 and the rim 32 through partitions 31. In the application shown in Fig. 1 closure of a hand switch 49 enables lines 51 to . supply current to lamps 43 for the cinema hall and closure of a hand switch 48 connects the lines 51 also to the secondary of a transformer 53 which supplies current through a switch 45 to an electromagnet 44 which closes a switch 37, enabling a dynamo 36 to supply current to the arc 4 of the projector, and a switch 39 which completes a further circuit to the motor 38 driving the film. Movement of a switch 41 to the left completes a circuit to an indicator lamp 52<1> indicating safety. The switch 49 is then opened and the hall darkened. When the film 17 breaks the pulley 26 stops and the balls complete a circuit between points A and B thus energizing an electromagnet 47 which closes a maintaining circuit for itself at 46 and a switch 42 which conducts current direct to the lamps 43 thus lighting up the hall. Switch 45 is simultaneously opened breaking the circuit to magnet 44 and causing the opening of switches 37 and 39 and the consequent extinction of the arc 4 and stoppage of the motor 38. A shutter 40 between the arc 4 and the film is also actuated. When the break down has been rectified the switch 41 is pushed to the right thereby lighting indicator lamp 52 and extinguishing the " safety lamp 52<1>. 1. The displacement of the switch 41 also opens the circuit to the magnet 47 causing switches 42, 46 to open and 45 to close, so that current again passes to the magnet 44 which closes switches 37, 39 so that the installation again functions normally. In addition to the shutter 40 other shutters separating the projection room from the hall or closing the film storage compartment may be simultaneously operated.