Dispositif pour produire des impulsions de courant destinées à alimenter une charge, notamment des clignoteurs de véhicule automobile

摘要

936,274. Road traffic signals. W. E. O'SHEI. Jan. 8, 1960 [May 22, 1959], No. 17442/59. Class 118. In a turn indicating system for flashing lamps R1, R2 or L1, L2 in combination with pilot lamp PR or PL, respectively, the flasher unit comprises a relay A having a low resistance starting winding 2 and a high resistance delay winding 1 which is connected in series with a condenser 3, the winding 1 and condenser 3 being normally short-circuited by the relay contacts A1. Upon operation of the selector switch S to the right, say, a heavy current flows and the lamps R1, R2 and PR are illuminated, the relay operates immediately and the opening of contacts Al douses the lamps. Condenser 3 then charges in series with the relay windings and the lamps, the latter remaining unlighted, and the charging current through the delay winding 1 keeps the relay A energized until the condenser 3 is nearly charged. At this point the current falls below the holding value and the relay A releases. Closure of contacts A1 completes the starting circuit again thus re-lighting the lamps. Simultaneously, the condenser 3 discharges through the delay winding 1, thus producing a field in opposition to that produced by the battery current flowing in the starting winding 2 and delaying the closure of the contacts A1 until the condenser 3 has discharged sufficiently to allow the starting winding field to attract the relay armature. The contacts A1 then open and the cycle is repeated. If the load is increased or decreased, the frequency of the pulsing will change accordingly, and if the load current falls below a predetermined value the starting winding field will be insufficient to operate the relay. The circuit is so designed that this predetermined value of load current is greater than that taken by either R1 and PR or R2 and PR, but less than that taken by R1, R2 and PR, so that if a lamp R1 or R2 burns out the pulsing circuit will not start when switch S is thrown to the right, and pilot lamp PR will remain continuously alight to indicate the fault condition. A resistor may be switched into circuit under control of the side light switch (not shown), in series with the lamps so as to dim them during the hours of darkness.