Patent GB-670841-A (GB)
Title: Improvements in or relating to electric remote control systems
Inventor: MACKINTOSH JAMES EWEN
IPC: G05D3/12
Filed: 1949-12-22
Abstract: 670,841. Electric selective signalling. MINISTER OF SUPPLY. Oct. 27, 1950. [Dec. 22, 1949] No. 32878/49. Class 40 (i). Relates to electric remote control systems for positioning a shaft in any one of a finite number of angular positions under the control of a remote switch. According to the invention, the shaft h is coupled to a commutator S1 comprising a plurality of fixed segments 1-9 and two rotatable ganged wipers A<SP>11</SP> B<SP>11</SP> each adapted to engage a separate one of any two adjacent segments, the segments being connected by individual lines to the switch s which is adapted to apply a negative potential from battery K to segments 1 to n and a positive potential to segments (n + 1) to 9 where n is any desired integer and means being provided for rotating the shaft when the two contacted segments are of like polarity and then stopping said rotation when the contacted segments have different polarities. The invention is described as applied to a system comprising three commutators S1, S10, S100 each having 10 segments and three switches s corresponding to hundreds, tens and units, the commutators being geared together by 10 : 1 reduction gears G1 and G2 so that the shaft h can be positioned to any one of a thousand settings at intervals of 36 degrees and the commutators being interconnected by relays so that they are effective sequentially. As shown, the shaft h is driven by motor m either directly through dogs d1 of clutch d or through reduction gear G3, intermittent reduction gear G4 and dogs d2 depending on whether the clutch-control relay f is energized or not and the motor is energized to rotate shaft h in a clockwise or anticlockwise direction by changing over relay contact ml or n1. The datum segment 0 of each commutator is divided into two contact areas a and b, permanently maintained at positive and negative potentials respectively and the wipers A and B of all the commutators are such that A can contact a only and B can contact b only. Relays P and Q are connected between wipers A, B and A<SP>1</SP> B<SP>1</SP> respectively. When the system has taken up a given position, e.g. 693 as shown, relays P and Q are energized thereby connecting wipers A<SP>11</SP>, B<SP>11</SP> to relays M, N but since A<SP>11</SP>, B" are at positive and negative potentials respectively relays M, N are not energized and consequently motor m is not energized. When the positions of all three switches s are changed, relays P and Q release thereby energizing relay f and connecting wipers A, B to relays M, N, one of which will be energized depending on whether the hundreds switch s has. been advanced or retarded so that the motor m is energized to rotate shaft h and all the wipers in the correct direction. When wipers A, B have reached the correct setting, relay P releases thereby connecting wipers A<SP>1</SP>, B<SP>1</SP> to relays M, N and the process is repeated until wipers A<SP>1</SP>, B<SP>1</SP> are correctly positioned when relay Q releases thereby connecting wipers A<SP>11</SP>, B<SP>11</SP>, to relays M, N and releasing the clutch relay f so that the final adjustment is performed slowly and intermittently.