Patent GB-570369-A (GB)
Title: Improvements in cabinet type motion picture projector
IPC: G03B29/00
Filed: 1943-03-18
Abstract: 570,369. Coin-freed kinematographs. AMPRO CORPORATION. March 18, 1943, No. 4405. Convention date, March 19, 1942. [Class 27] Kinematograph apparatus for coiled endless film, with sound and optical piok-up, is started by insertion of a coin and stopped under control of the film and is adapted to return the coin if the projector lamp burns out, or the film breaks and to carry on with the sound only, or without the sound, suitable indication of these two alternatives being made. The apparatus will operate on A.C. or D.C. supply. A separate projector exhibits still pictures in the intervals between coinfreed operations. The cabinet is airtight apart from openings 13 with dust filter covers 19, an outlet 15, and an opening for air to cool the amplifier 43. The front panel carries two loudspeakers 25 with dust-proof covers 27 and decorative lights 29, and, above, a translucent screen 23 receiving the picture projected by mirrors 37 and 39. The -still picture is projected by a lantern 49 and mirror 50. The speakers 25 taking 90 per cent of the output from the amplifier 43 mainly give the low audio frequency, the high being given by a third speaker 31 above the screen. A terminal board 51 carrying transformer, switch, and fuses is mounted in a fireproof box. If the supply is D.C. only the transformer 101, the amplifier 43 and the projector motor 99, Fig. 3, are fed from the converter 97 which is thus only of suitable reduced size and rating. A switch 133 cuts it out on A.C'. supply. Coin action ; control by film.-An inserted coin closes momentarily switch 135 to energize an add coil 147 and move in the credit direction a wheel 151, an arm 153 on which closes contact with 155 to start operation, and a hole on the film at the end of a picture operates a switch 139 to energize a coil 149 to reverse and debit the wheel 151. If several coins are inserted credit is built up and a corresponding number of films are shown before an equal debit opens the switch 155 to stop operation. A switch 157 is opened by the add coil 147 to prevent subtraction while coins are inserted. A break in the film breaks contact at 125 to stop operation and if the projector lamp 77 burns out, a relay 86 fails to maintain contacts 227, 229 and a coil 137 fails to collect the coin and returns it to the customer. Where mains are D.C. under normal conditions the converter will be running and in operative condition all the time, and a heater circuit for the amplifier will be supplied to stand by terminals 117, through wires 73, 127, switch 125, 123, 121 and 119 and to common input terminal 111 through wires 115 and 107, the " run " terminal input 129 being connected through wire 91 and the control switch 93 and wire 73 to the common output terminal 75 of the converter. The projector motor is energised over 107 fuse 105 wire 103 and return 109, 89, 91, control switch 93, and 73 to 75. The transformer primary is also energized from the converter over the film break switch 125 and supplies power for the control coils 163, 165, the coin collector coil 137, and the add and subtract coils 147, 149, the secondary giving 24 volts for these and having a tap at 6 volts for the pilot and decorative lights. Closure of contact 153, 155 on entry of a coin energizes coil 163 from the transformer secondary over wires 191 and 201 to close control switch 93, and also energizes coil 165 to open switches 187 and 171 to put out the still projector and pilot lamps. A current and voltage responsive relay 86 in circuit with the motion projector maintains at contacts 227, 229 the circuit of the coincollector coil 137 so that coins are returned if the lamp burns out. If desired, the circuit may be arranged to accept coins and operate on sound only, as shown in Fig. 4, where the relay 8b out of normal action is provided with lower contacts 239, 241 to show a corresponding indication and the patron would be directed by a sign to press a button switch 251, while inserting a coin, to put the collecting coil 137 in action. It may be desired to indicate when the exciter lamp has burnt out and for this a relay 269, Fig. 5, is connected in the circuit 191, 193, shown in Fig. 3, so as, during each run of a film, to complete the circuit at 267, 271 of the exciter lamp 265, so disconnecting a " no sound " indicator 281 by energizing a coil 273. Failure of the exciter lamp puts in the switch 279 and gives the " no sound " indication.