Methods of and apparatus for testing articles to determine to which of three groups the articles belong

Claim 1

THE METHOD OF TESTING A SERIES OF ARTICLES TO DETERMINE TO WHICH ONE OF THREE GROUPS EACH OF THE ARTICLES BELONGS ACCORDING TO THE VALUE OF A CHARACTERISTIC THEREOF, THE CHARACTERISTIC BEING ONE WHICH UNDER TEST CONDITIONS IS CAPABLE OF VARYING THE MAGNITUDE OF AN ELECTRICAL REFERENCE SIGNAL AS A FUNCTION OF THE VALUE OF THE CHARACTERISTIC, WHICH METHOD COMPRISES: (A) PLACING EACH ARTICLE IN TURN UNDER TEST CONDITIONS TO PRODUCE A REFERENCE SIGNAL REPRESENTATIVE OF THE VALUE OF THE CHARACTERISTIC; (B) APPLYING THE REFERENCE SIGNAL TO A SENSING DEVICE OF THE TYPE WHICH OPERATES INITIALLY ONLY WHEN THE REFERENCE SIGNAL IS ABOVE A FIRST PREDETERMINED VALUE CORRESPONDING TO A FIRST REFERENCE VALUE OF THE CHARACTERISTIC UNDER TEST, SO THAT THE ARTICLE IS KNOWN TO BELONG TO A FIRST ONE OF THE THREE GROUPS WHENEVER THE DEVICE OPERATES AS A RESULT OF STEP (B); (C) MOMENTARILY APPLYING A STRONGER SIGNAL TO THE SENSING DEVICE SUFFICIENT TO INSURE THAT IT OPERATES WHENEVER THE DEVICE DOES NOT OPERATE IN STEP (B); AND (D) APPLYING THE REFERENCE SIGNAL TO THE SENSING DEVICE WHILE THE DEVICE REMAINS OPERATED AS A RESULT OF STEP (C), THE DEVICE BEING FURTHER OF THE TYPE WHICH REMAINS OPERATED UNLESS THE REFERENCE SIGNAL IS BELOW A SECOND PREDETERMINED VALUE LOWER THAN THE FIRST AND CORRESPONDING TO A SECOND REFERENCE VALUE OF THE CHARACTERISTIC UNDER TEST, SO THAT THE ARTICLE IS KNOWN TO BELONG TO A SECOND GROUP WHENEVER THE DEVICE REMAINS OPERATED AS A RESULT OF STEP (D) AND SO THAT THE ARTICLE IS KNOWN TO BELONG TO A THIRD GROUP WHENEVER THE DEVICE DOES NOT REMAIN OPERATED AS A RESULT OF STEP (D).

Claim 2

THE METHOD OF TESTING A SERIES OF ARTICLES TO DETERMINE TO WHICH ONE OF THREE GROUPS EACH OF THE ARTICLES BELONGS ACCORDING TO THE VALUE OF A CHARACTERISTIC THEREOF, THE CHARACTERISTIC BEING ONE WHICH UNDER TEST CONDITIONS IS CAPABLE OF VARYING THE MAGNITUDE OF AN ELECTRICAL REFERENCE SIGNAL AS A FUNCTION OF THE VALUE OF THE CHARACTERISTIC, WHICH METHOD COMPRISES: (A) PLACING EACH ARTICLE IN TURN UNDER TEST CONDITIONS TO PRODUCE A REFERENCE SIGNAL REPRESENTATIVE OF THE VALUE OF THE CHARACTERISTIC; (B) APPLYING THE REFERENCE SIGNAL TO A SENSING DEVICE OF THE TYPE WHICH OPERATES INITIALLY ONLY WHEN THE REFERENCE SIGNAL IS ABOVE A FIRST PREDETERMINED VALUE CORRESPONDING TO A FIRST REFERENCE VALUE OF THE CHARACTERISTIC UNDER TEST, SO THAT THE ARTICLE IS KNOWN TO BELONG TO A FIRST ONE OF THE THREE GROUPS WHENEVER THE DEVICE OPERATES AS A RESULT OF STEP (B); (C) MOMENTARILY APPLYING A STRONGER SIGNAL TO THE SENSING DEVICE SUFFICIENT TO INSURE THAT IT OPERATES WHENEVER THE DEVICE DOES NOT OPERATE IN STEP (B); AND (D) APPLYING THE REFERENCE SIGNAL TO THE SENSING DEVICE WHILE THE DEVICE REMAINS OPERATED AS A RESULT OF STEP (C), THE DEVICE BEING FURTHER OF THE TYPE WHICH REMAINS OPERATED UNLESS THE REFERENCE SIGNAL IS BELOW A SECOND PREDETERMINED VALUE LOWER THAN THE FIRST AND CORRESPONDING TO A SECOND REFERENCE VALUE OF THE CHARACTERISTIC UNDER TEST, SO THAT THE ARTICLE IS KNOWN TO BELONG TO A SECOND GROUP WHENEVER THE DEVICE REMAINS OPERATED AS A RESULT OF STEP (D) AND SO THAT THE ARTICLE IS KNOWN TO BELONG TO A THIRD GROUP WHENEVER THE DEVICE DOES NOT REMAIN OPERATED AS A RESULT OF STEP (D).