GB793128A - Improvements relating to automatic programme control - Google Patents

Abstract

793,128. Sound-film apparatus. BRITISH THOMSON-HOUSTON CO., Ltd. Jan. 2, 1957 [Jan. 2, 1956], No. 62/56. Class 40 (2). Means for providing for the automatic performance of a programme of operations in a cinema (such as the switching of the projector, house lights and curtains), comprises means for automatically recording during an initial performance of the programme distinctive control signal respectively representing the various operations carried out, together with means for reproducing the recorded signals during a subsequent performance and utilizing them to control at appropriate times the respective operations which they represent. Fig. 1 illustrates one embodiment in which during an initial performance a starter switch ST energizes a contactor C to close C2 of a hold-on circuit completed through normally closed contacts of a switch SP and relay CR2. The operaton of starter switch ST also completes a circuit through contacts St2 and relay RR1 the contact of which becomes closed and connects the output of a note oscillator OSC 1 to a magnetic recording head WH. Release of starter ST terminates the signal being recorded but the contactor C circuits remain closed until stop switch SP is operated, whereby the projector motor and hold-on circuits are broken. At the same time, the circuit of relay RR2 is closed and the output from a different note oscillator OSC 2 is connected to magnetic head WH. During playback of the resulting record T by a head RH, tuned relays CR1 and CR2 are operated by the signals obtained from the record to operate starter ST and stop switch SP at the appropriate moments. Further circuits using oscillators of other frequencies may be used for controlling a number of other operations. An alternative arrangement is suggested in which the relays effect a different number of recorded pulses according to the operational control desired, the decoding of the signals being obtained by some form of pulse counter. A second embodiment is described in which a common frequency is employed for the signals representing the various operations and in which a separate track on a magnetic tape is used for each operational control signal.