Control of variable pitch stator blades or vanes in axial flow machines

Claim 1

IN COMBINATION, A CONTROL MEMBER AND APPARATUS FOR AUTOMATICALLY ADJUSTING SAID CONTROL MEMBER, SAID APPARATUS COMPRISING TWO CONDITION SENSITIVE DEVICES ADAPTED TO RESPOND RESPECTIVELY TO THE VALUES OF TWO INDEPENDENTLY VARIABLE OPERATING CONDITIONS, EACH DEVICE INCLUDING AN OUTPUT MEMBER WHICH EXERTS A THRUST WHICH VARIES IN ACCORDANCE WITH VARIATIONS IN THE RESPECTIVE CONDITION, A FLOATING DIFFERENTIAL LEVER NORMALLY OCCUPYING A NEUTRAL POSITION, AND A MOVABLE FULCRUM BEARING ON THE LEVER AND ACTING AS A REACTION MEMBER, THE OUTPUT MEMBERS OF THE CONDITION SENSITIVE DEVICES BEING OPERATIVELY CONNECTED TO THE DIFFERENTIAL LEVER AT SPACED POINTS IN ITS LENGTH SO AS TO OPPOSE ONE ANOTHER THROUGH THE MOVABLE FULCRUM SO THAT AN INCREASE IN ONE VARIABLE TENDS TO MOVE SAID LEVER FROM SAID NEUTRAL POSITION IN A DIRECTION OPPOSITE TO THAT IN WHICH IT IS MOVED BY AN INCREASE IN THE OTHER VARIABLE, SERVO MEANS CONNECTED TO THE FULCRUM TO CONTROL ITS LONGITUDINAL POSITION SO AS TO VARY THE DIFFERENTIAL RATIO OF THE LEVER BETWEEN THE POINTS OF APPLICATION OF THE OUTPUT MEMBERS OF THE CONDITION SENSITIVE DEVICES, MEANS SENSITIVE TO MOVEMENTS OF THE LEVER AND CONNECTED TO AND ACTUATING SAID SERVO MEANS IN RESPONSE TO MOVEMENT OF SAID DIFFERENTIAL LEVER IN EITHER DIRECTION FROM SAID NEUTRAL POSITION TO AUTOMATICALLY MOVE THE FULCRUM TO PROVIDE A BALANCE BETWEEN THE TWO OPPOSING FORCES AND CAUSE SAID LEVER TO RETURN TO ITS NEUTRAL POSITION, AND CONNECTION MEANS BETWEEN THE CONTROL MEMBER AND SAID MOVABLE FULCRUM FOR ADJUSTING SAID CONTROL MEMBER IN RESPONSE TO MOVEMENTS OF SAID MOVABLE FULCRUM, SAID CONNECTION MEANS INCLUDING CAM MEANS TO PROVIDE THE REQUIRED NON-LINEAR RELATIONSHIP BETWEEN THE MOVEMENT OF THE FULCRUM AND THE MOVEMENT OF THE CONTROL MEMBER.