Apparatus for automatic testing of a potentiometer's linearity and total resistance including actuating means responsive to a predetermined percent of error

Claim 1

A POTENTIOMETER TESTER COMPRISING IN COMBINATION; HOLDING MEANS FOR HOLDING A POTENTIOMETER UNDER TEST INCLUDING LEADS FOR COUPLING TO A DIRECT CURRENT SOURCE; A CODE HOLDER FOR HOLDING A CODE OF RADIX POWERS AND COEFFICIENTS; MOVING MEANS COUPLED TO SAID HOLDING MEANS AND SAID CODE HOLDER FOR SIMULTANEOUSLY TURNING SAID POTENTIOMETER ALONG THE WIPER POSITIONS THEREOF AND MOVING SAID CODE HOLDER ALONG A PREDETERMINED PATH OF TRAVEL; CODE READING MEANS ADJACENT SAID CODE HOLDER AND HAVING SEPARATE OUTPUT SIGNAL PRODUCING MERANS FOR EACH RADIX POWER AND COEFFICIENT WHICH CAN BE READ; A RELAY HAVING WINDINGS COUPLED TO EACH OF SAID SEPARATE OUTPUT SIGNAL MEANS AND RESPONSIVE THERETO; A RELAY OPERATED VOLTAGE DIVIDER INCLUDING INPUT AND OUTPUT LEADS AT THE ENDS FOR CORRECTION TO SAID SOURCE IN A CLOSED CIRCUIT, SAID RELAY OPERATED VOLTAGE DIVIDER HAVING A CENTER TAP AND TWO SETS OF IN SERIES RESISTORS ON THE ONE AND THE OTHER SIDE OF SAID CENTER TAP ADAPTED TO BE SWITCHED IN OR SHORTED OUT OF A BANK OF RESISTORS, THERE BEING ONE RESISTOR IN EACH SET HAVING AN OHMIC VALUE CORRESPONDING TO A RADIX POWER OR COEFFICIENT OF A CODE HELD BY SAID CODE HOLDER, EACH ONE OF SAID RELAYS HAVING A PAIR OF SWITCHES CONNECTED TO ENERGIZE RESISTORS IN EACH SET HAVING AN OHMIC VALUE CORRESPONDING TO THE PARTICULAR RADIX POWERS OR COEFFICIENTS READ AT SAID STATION, SAID SWITCHES SWITCHING IN AND SHORTING OUT RESISTORS IN EACH SET HAVING THE SAME OHMIC VALUE, SO THAT THE TOTAL RESISTORS IN SAID BANK BETWEEN SAID INPUT LEAD AND CENTER TAP WILL CORRESPOND IN OHMIC VALUE TO SAID RADIX POWERS AND COEFFICIENTS AT SAID STATION; A SERVO NULL DETECTOR TO WHICH IS FED THE OUTPUT OF SAID CENTER TAP AND SAID WIPER, SAID DETECTOR HAVIN A NULL VALUE WHEN SAID OUTPUTS ARE EQUAL; POLARITY RESPOSIVE OUTPUT TRIGGER MEANS RESPONSIVE TO SAID DETECTOR AND ELECTROMECHANICAL MEANS RESPONSIVE TO SAID TRIGGERS, ONE TRIGGER CAUSING SAID ELECTROMECHANICAL MEANS TO MOVE IN ONE DIRECTION WHEN SAID DETECTOR HAS A VALUE BELOW THE NULL VALUE, THE OTHER TRIGGER CAUSING SAID ELECTROMECHANICAL MEANS TO MOVE IN THE OTHER DIRECTION WHEN SAID DETECTOR CIRCUIT HAS A VALUE ABOVE SAID NULL VALUE; STEPPED RESISTORS CONNECTED IN SERIES IN SAID DETECTOR CIRCUIT, SO DISPOSED THAT RESISTORS ARE ADDED TO SAID DETECTOR CIRCUIT WHEN SAID ELECTROMECHANICAL MEANS MOVE IN ONE DIRECTION WHEREAS RESISTORS ARE DEDUCTED FROM SAID DETECTOR CIRCUIT WHEN SAID ELECTROMECHANICAL MEANS MOVE IN THE OTHER DIRECTION; MEMORY CONTACTS CORRESPONDING TO EACH OF SAID STEPPED RESISTORS AND BEING ENGAGED BY SAID ELECTROMECHANICAL MEANS WHEN A STEPPED RESISTOR IS ADDED OR DEDUCTED FROM SAID DETECTOR CIRCUIT, EACH MEMORY CONTACT BEING COUPLED WITH ANOTHER MEMORY CONTACT WHICH IS SEPARATED THEREFROM BY THE AMOUNT OF STEPPED RESISTORS TOTALLING THE MAXIMUM PREDETERMINED PERMISSIBLE NUMBER OF ERRORS; MEMORY MEANS REMEMBERING AND TOTALLING THE FIRST ENGAGEMENT OF EITHER ONE OF ANY OF SAID COUPLED MEMORY CONTACTS; AND SIGNAL MEANS GIVING A SIGNAL WHEN SAID TOTAL EXCEEDS SAID PREDETERMINED PERMISSIBLE NUMBER.