Patent GB-703737-A (GB)
Title: Improvements in or relating to stroboscopic indicator
IPC: G09F9/40
Filed: 1951-12-27
Abstract: 703,737. Digital electric calculating-apparatus. MONROE CALCULATING MACHINE CO. Dec. 27, 1951 [Dec. 29, 1950], No. 30204/51. Class 106 (1). [Also in Groups XX and XL(b)] A stroboscopic indicator, e.g. for read-out from an electronic computer, comprises a rotatable member having characters thereon which are selectively illuminated by lamps each periodically excited from the tens carry output circuit of an electronic counter presettable to represent digits to be displayed and having counting pulses, ten per rotation of the member, applied thereto through gating means which is enabled to pass these pulses by the first of a series ot reference pulses, one provided per rotation, after a read-out switch has been operated, and disabled by the first reference pulse following normalizing of the switch. Construction.-The cylinder 1, Fig. 1, has end members 2, 3 and is constantly rotated by a motor 10. Member 2 extends through and is supported by ball bearing 4 carried by disc 6 frictionally held in cylindrical housing 8 by an expandible rubber grommet G. Member 3 is supported by ball bearing 5 and stationary tube 12 held by flange 13 and threaded cap 14a, the tube supporting a lamp housing 19 the other end of which is supported by ball bearing 18 from member 2. The cylinder has a coating which is removed to form transparent numerals which are illuminated in display window 9 by lamp 20; and interposed lamps 21, covered by apertured masks 24, are selectively lit to indicate a decimal point at the position of one of the transparent rings 63. The lamp conductors are connected to connector prongs 75. A further continuously lit lamp 25, Fig. 6, shines through cylinder slits 29, 30 to excite pholo-cells 26, 27 respectively. is first Operation.-The number to be indicated is first transmitted from a data source, e.g. an electronic computer, over conductors 31, Fig. 6, to electronic decade counters 32, one for each decimal denomination, previously reset to zero by switch 34. The counters may be of a known kind each comprising a decimal-coded arrangement of four cascade-connected triode trigger pairs, and have their carry output circuits connected through amplifiers 49 to corresponding flash lamps 20. Owing to slit 29, one pulse per revolution of the cylinder 1 passes from photo-cell 26 through amplifier 43 to the grids of triodes 38, 39. Triode 38 conducts since earth potential is applied to point a through read-out switch 33, thus maintaining conduction in associated triode 40 of trigger pair 40, 41. Operation of switch 33, however, energizes relay 35 to apply earth potential to point f, instead of a, and to connect the counter inputs to the output circuit of gate valve 37. Thus the next pulse from 43 causes conduction in triode 39 thereby switching over trigger 40, 41 and raising the potential of point c, so that the subsequent pulses (ten per revolution) passed from photo-cell 27 (associated with slits 30) through amplifier 44 cause valve 37 to conduct, thus applying actuating pulses to all the counters. At differential times, dependent on the digits initially registered, carry output pulses will be applied to lamps 20 to illuminate corresponding digits on the cylinder once per revolution. In a modified arrangement for entering data into the counters, Fig. 7 (not shown), the data is initially registered on other triode trigger pairs and is introduced into the counters by a single operation of a " transfer " switch.