GB477444A - Improvements in or relating to indicating apparatus for use with timed operations - Google Patents

Abstract

477,444. Clock-driven indicators. LANGBEIN, H. W. May 3, 1937, No. 13720/36. [Class 118 (i)] An indicator for use at cinema theatres, railway stations, and other places, is automatically operated to show progressively the number of units of time through which a timed operation has still to pass before the completion of the operation, and to display such information for each of a sequence of differently timed operations. Timed electric impulses are transmitted to a solenoid 4 to actuate a pawl 9 engaging a toothed wheel 14 which moves a slider 15 on a rheostat 16 in circuit with a galvanometer 17 forming the indicator. The " time to elapse " pointer 18, which is progressively restored to zero as the operation proceeds, is pre-set to the desired amount by turning a knob 30 to set a rotatable stop 24. An electricallycontrolled pawl 39 is then released from the wheel 14 to permit the spring-urged shaft 11 to move the slider 15 until an arm 33 engages the stop 24. The pointer 18 then shows a reading corresponding to that of the dial 31 on the panel 32, When the operation is finished the arm 33 closes a switch 36 to operate (a) a selector 39a which cuts out the rheostat unit 16, and (b) a selector 21 to cut out the lamp illuminating the corresponding item on the indicator board 19. At the same time the solenoid 40 is operated through a delay action switch to release the wheel 14 and reset the arm 34 against the stop 24. A centrifugal governor brake 44 damps the action of the return spring 37a. For each of the three items on the indicator 19 there is provided a separate rheostat unit connected to the main selector 39a and the indicator selector 21. Means are provided for preventing surplus selector pins 59 from closing a redundant circuit, when certain items on the programme are eliminated. The " interval " lamp 56 is controlled by a rocking mercury switch 55. Tell-tales are provided to show the operator the position in which the various units are at any moment. In place of the pointer a spot of light or an illuminated line or slot may be used.