GB956302A - An electrical selector system - Google Patents

Abstract

956,302. Electric selective signalling. W. H. SHORT. Feb. 15,1963 [Nov. 16, 1961; Dec. 22,1961; Feb. 7, 1962], Nos. 41094/61, 45976/61 and 4651/62. Heading G4H. An electrical selector system comprises a control unit 1, with an operating switch 7, controlling a loop 6 containing one or more controlled units 2-5, wherein on a first actuation of switch 7, pulses from unit 1 scan one switch in each of units 1-5 in turn ("main-scan"), a second actuation of switch 7 during the scanning of the switch in one of the units 2-5 stopping the main-scan and initiating scanning of a sequence of function switches in the thus selected unit 2, 3, 4 or 5 ("sub-scan"), a third actuation of the switch 7 during a sub-scan setting into operation the function whose switch has just been reached, the sub-scan continuing until the main-scan.is renewed by selecting (by actuating switch 7) a certain function switch (called "transfer" switch). The system can be used for the control of various amenities (list &c. given) by a bedridden patient. The progress of the scanning is indicated by lamps on the units being scanned. Each controlled unit contains a "stop" function switch which when selected stops the pulse generation, and therefore the sub-scan, the latter being resumed when switch 7 is pressed again. The radiogram unit 3 has further sets of switches associated with the function switches, a set being scanned when the associated function switch is selected, to enable control of volume or &c. by selecting one of the set. A priority unit 9 is provided, not in the loop 6, a sub-scan of it being initiated when a "priority" function switch is selected during the sub-scan of one of the units 2-5 of the loop 6, this action terminating the sub-scan of the loop unit. The latter is resumed if a "transfer" function switch is selected during the sub-scan of the priority unit 9. When an amenity controlled by the priority unit 9 is selected, audible devices in the loop 6, which have been set operating, are automatically switched off. A general facilities unit 5 controls a number of amenities, plugged into it, switching one on when a corresponding relay, scanned during the sub-scan of unit 5, is selected. If the relay is selected again, the apparatus is switched off The same applies to the priority unit 9. The system can be switched off by selecting the control unit 1 during a main-scan. The prf of the pulse generator can be varied. The switches which are selected, other than in the main-scan, are the contacts of uniselector-operated wipers. Multicore cables connect the units 1-5, 9, plugging into each, enabling extra units to be added into the loop 6. Fig. 2, (not shown) shows a more complicated system, wherein one of the units in the loop is a distribution unit enabling scanning to be transfered to one of three subsidiary loops, one of these similarly having two further loops appendant to it. Figs. 3-7, (not shown) give various circuit diagrams.