GB905034A - Cinematograph projector - Google Patents

Abstract

905,034. Kinematograph apparatus. ZEISS IKON A.G. March 9, 1959 [March 13, 1958], No. 8107/59. Class 97 (1). Cinematograph projector incorporates switch means serving in operation to switch off the film feed, a switch actuating member operatively associated with said switch means and adapted, in operation, to occupy a position dependent on the tension of film running through the projector, and delay action means operating directly on said switch actuating member and serving to delay switching off said switch means after such switching off has been initiated by the film. As shown, film 1 passes over a fixed slide 2 and between rollers 5 and 6, roller 5 being mounted on one end of a lever 10 which is pivoted about a bolt 11 and has a rear arm operating a switch 12 controlling-through a relay-the current supply to the film driving motor. The roller is kept in contact with the film by its own weight or by spring-biasing, and opens the switch 12 if the film breaks or if its tension drops below a predetermined level. So that short fluctuations in film tension do not operate the switch, movements of lever 10 are delayed by an air-damped piston arrangement 13, 14. The film may also have metal coatings, for example 8 and 9, which co-operate with pairs of contacts 3, 31 and 4, 4<SP>1</SP> to control certain operations in the projector. An R.C. delay network may be associated with one of the pairs of contacts.