Automatic flushing system

An automatic flushing system for flushing a plurality of toilet bowls installed in a lavatory at various intervals according to the frequency at which the toilet bowls are used, the system comprising a detecting device for delivering a detection signal upon detecting each person entering the lavatory;

• a solenoid-controlled valve for flushing the toilet bowls;
• a first command circuit for delivering a first output signal in response to a detection signal delivered first from said detecting device after the flushing of the toilet bowls;
• a first signal-transmitting circuit having a first timer which starts upon receipt of the first output signal and stops upon lapse of a first reference time, thereby to deliver a second output signal when the first timer stops;
• a timer for delivering, upon receipt signal, a third output signal which lasts for a predetermined time to control the solenoid-controlled valve;
• means for actuating the solenoid-controlled valve upon receipt of the third output signal, thereby to flush the toilet bowls;
• a second command circuit for delivering a fourth output signal to the first signal-transmitting circuit upon receipt of every detection signal, in response to each detection signal delivered subsequent to the first one delivered after each flushing of the toilet bowls, thereby to set in said first timer a time shorter than the first reference time by a predetermined length;
• a third command circuit for delivering a fifth output signal after each flushing of the toilet bowls in case the detecting appliance delivers no detection signal;
• and a second signal-transmitting circuit having a second timer which starts upon receipt of the fifth output signal and stops every time a second reference time longer than the first one elapses, thereby to deliver, when the second timer stops, a sixth output signal to said timer so as to flush the toilet bowls.