Pneumatic servo-positioner unit

Claim 1

IN A PNEUMATICALLY-POWERED RECORDER SYSTEM; A MARKER SUPPORTED AND DISPOSED FOR MOVEMENT IN EITHER OF TWO SUBSTANTIALLY OPPOSITE DIRECTIONS, MEANS FOR HAVING RECORDED THEREON BY SAID MARKER A GRAPH AND SUPPORTED AND DISPOSED FOR MOVEMENT IN A DIRECTION ANGULAR WITH RESPECT TO THE DIRECTION OF SAID MOVEMENT OF SAID MARKER, AND A PNEUMATIC ACTUATOR AND SERVO-POSITIONER UNIT FOR IMPARTING SAID MOVEMENT TO SAID MARKER AND PROVIDED END-TO-END THEREOF WITH AN OPENING; SAID UNIT COMPRISING AN ELEMENT DISPOSED IN SAID OPENING FOR MOVEMENT IN EITHER DIRECTION ALONG ITS AXIS TO ANY GIVEN AXIAL POSITION AND SO DISPOSED WITH ITS SAID AXIS SUBSTANTIALLY COAXIAL WITH RESPECT TO SAID OPENING, A DIAPHRAGM FIXED WITH RESPECT TO SAID ELEMENT, DIFFERENTIAL-PRESSURE MEANS RESPONSIVE TO INPUT-SIGNAL PRESSURE APPLIED TO SAID UNIT, VALVE MEANS ENGAGED WITH RESPECT TO AND CONTROLLED BY SAID DIFFERENTIALPRESSURE MEANS AND AS SO CONTROLLED FUNCTIONAL TO DERIVE FROM SUBSTANTIALLY CONSTANT POSITIONER-SUPPLY PRESSURE APPLIED TO SAID UNIT DERIVATIVE VALUES OF SUCH PRESSURE, SAID UNIT BEING PROVIDED WITH A PASSAGE FOR THE APPLICATION TO SAID DIAPHRAGM OF SAID DERIVATIVE VALUES OF SAID POSITIONER-SUPPLY PRESSURE, AND A COIL SPRING DISPOSED ABOUT SAID ELEMENT BETWEEN SAID DIAPHRAGM AND SAID DIFFERENTIALPRESSURE MEANS; AND MEANS CONNECTING SAID ELEMENT AND SAID MARKER FOR SAID MOVEMENT OF THE LATTER IN A DIRECTION AND TO AN EXTENT CORRESPONDING TO THE DIRECTION AND EXTENT OF MOVEMENT OF SAID ELEMENT, SAID SPRING BEING COMPRESSED BETWEEN SAID DIAPHRAGM AND SAID DIFFERENTIALPRESSURE MEANS AND FUNCTIONAL IN ACCORDANCE WITH THE EXTENT OF ITS COMPRESSION TO GIVE TO SAID UNIT A SERVOPOSITIONING CHARACTERISTIC WITH RESPECT TO SAID ELEMENT THUS TO HOLD THE LATTER AND SAID MARKER IN REPOSE AT THEIR RESPECTIVE GIVEN POSITIONS FOR THE PARTICULAR DERIVATIVE VALUE OF POSITIONER-SUPPLY PRESSURE BEING SUPPLIED TO SAID DIAPHRAGM.