GB845543A - Improvements relating to electrically-operated changing display indicators - Google Patents

Abstract

845,543. Indicators for electric selective systems. SIEMENS EDISON SWAN Ltd. Nov. 6, 1958 [Nov. 18, 1957], No. 35858/57. Class 40 (1). In an indicator of the kind in which one of a series of letters or numbers can be displayed by moving a chain of display slats 3-12, Figs. 2, 3, to a selected position by the earthing of certain ones of a number of parallel lines, each line has a switch, the switches being controlled during movement of the chain by coded projections on the edges of the slats so that in each different stopping position of the chain, a different combination of switches is opened, the chain being driven until the switches in all earthed lines are open. The chain of slats passes round sprocketwheels 13, 14 on axles 15, 16. Wheel 14 is driven through a gear-train and a Geneva gear by a motor 19. The switches each consist of a contact finger 27-31 held spaced apart by an insulating clamp 32 at the lower end and biased into contact with a contact-bar 34. As a slat passes round sprocket 14 it assumes a vertical position so that its coded edge engages the contact arms and lifts certain ones out of engagement with the bar 34. As shown in Fig. 4, the selector lines 38-41 are earthed by contacts 46-49 of selector relays. The mechanism is driven by motor 19 until the contact 27-30 in every earthed line is opened, the selected numeral then being presented at the display position. A fifth line when earthed by resetting switch 52 causes the mechanism to be driven to the initial position, in which position contact 31 is opened by a projection 37 on slat 5. To allow the motor to be energized between stopping positions a cam 50 rotating with sprocket 13 may close contact 51. The motor 19 may run continuously, driving the shaft 16 through a clutch controlled to display the required numeral by a solenoid and provided with a latching arrangement for accurately locating the slats. A number of indicators may be associated with the same driving motor. Specifications 721,683 and 845,542 are referred to.