Control apparatus

Claim 1

A CONTROL CIRCUIT FOR USE IN CONTROLLING AN AUTOMATIC DOOR INCLUDING A RELAY FOR ENERGIZING A DOOR OPERATOR ACTUATOR AND AN ELECTRONIC CONTROL CIRCUIT FOR THE RELAY CONTROL WHEREIN A FIRST SIGNAL IS REQUIRED TO OPEN THE DOOR AND A SECOND SIGNAL IS OPERATIVE TO MAINTAIN THE DOOR IN AN OPEN POSITION: THE IMPROVEMENT WHICH COMPRISES SEMICONDUCTOR CURRENT CONTROL MEANS HAVING A PAIR OF INPUT ELECTRODES AND A PAIR OF OUTPUT ELECTRODES; AN APPROACH SWITCH ADAPTED TO PROVIDE THE FIRST SIGNAL; A SAFETY SWITCH ADAPTED TO PROVIDE THE SECOND SIGNAL; A LOW VOLTAGE SOURCE; OUTPUT MEANS TO BE CONNECTED TO CONTROL A DOOR ACTUATOR; MEANS CONNECTING SAID OUTPUT MEANS TO SAID OUTPUT ELECTRODES; MEANS CONNECTING THE APPROACH SWITCH IN CONTROLLING RELATION TO THE INPUT ELECTRODES OF SAID SEMICONDUCTOR CURRENT CONTROL MEANS AND TO SAID LOW VOLTAGE SOURCE TO THEREBY ACTUATE SAID OUTPUT MEANS; AND MEANS CONTROLLED BY SAID OUTPUT MEANS WHEN IN SAID ACTUATED CONDITION TO CONNECT SAID SAFETY SWITCH IN CONTROLLING RELATION TO SAID INPUT ELECTRODES AND TO THE LOW VOLTAGE SOURCE TO MAINTAIN THE DOOR OPEN SO LONG AS THE SAFETY SWITCH IS IN AN ACTUATED CONDITION.