Positioning system and its control

Claim 1

A PRECISION POSITIONING SYSTEM ADAPTED TO OPERATE RELIABLY OVER A WIDE VARIETY OF CONDITIONS COMPRISING: (A) A POSITIONING MEANS FOR AN OBJECT BEING MANIPULATED, SAID POSITIONING MEANS BEING OPERATED BY FLUID FLOW ALTERNATELY INTO AND OUT OF ITS OPPOSITE SIDES; (B) AN ADJUSTABLE VALVE MEANS FOR DIRECTING FLUID FLOW ALTERNATELY INTO AND OUT OF THE OPPOSITE SIDES OF SAID POSITIONING MEANS, THE FIRST SIDE OF SAID POSITIONING MEANS BEING OPERATIVELY CONNECTED DIRECTLY TO THE FIRST SIDE OF SAID ADJUSTABLE VALVE MEANS BY A FLUID CONDUIT; (C) AT LEAST A FIRST AND A SECOND PARALLEL FLUID CONDUIT, ONE PAIR OF ADJACENT ENDS OF SAID PARALLEL FLUID CONDUITS BEING OPERATIVELY CONNECTED TO THE SECOND SIDE OF SAID POSITIONING MEANS AND THE OTHER PAIR OF ADJACENT ENDS BEING OPERATIVELY CONNECTED TO THE SECOND SIDE OF SAID ADJUSTABLE VALVE MEANS; (D) A FIRST CHECK VALVE MEANS IN SAID FIRST PARALLEL FLUID CONDUIT ADAPTED TO NORMALLY PERMIT FLUID FLOW ONLY FROM SAID ADJUSTABLE VALVE MEANS TOWARD SAID POSITIONING MEANS; (E) A SECOND CHECK VALVE MEANS IN SAID FIRST PARALLEL FLUID CONDUIT ADAPTED TO PERMIT FLUID FLOW ONLY FROM SAID POSITIONING MEANS TOWARD SAID ADJUSTABLE VALVE MEANS; (F) A METERING VALVE MEANS IN SAID FIRST PARALLEL FLUID CONDUIT ADAPTED TO PERMIT FLUID FLOW THERETHROUGH AT A PREDETERMINED RATE; AND (G) A REGULATING VALVE MEANS IN SAID SECOND PARALLEL FLUID CONDUIT, SAID REGULATING VALVE MEANS COMPRISING: (I) A PISTON IN A CYLINDER THEREIN ADAPTED TO MOVE FREELY THROUGH A STROKE OF PREDETERMINED LENGTH, SAID PISTON HAVING A FLUID CONDUIT THERETHROUGH, (II) A THIRD CHECK VALVE MEANS IN THE FLUID CONDUIT IN SAID PISTON ADAPTED TO PERMIT FLUID FLOW ONLY IN A DIRECTION FROM SAID POSITIONING MEANS TOWARD SAID ADJUSTABLE VALVE MEANS, (III) A FIRST STOP MEANS MOUNTED ON SAID PISTON FOR ARRESTING ITS MOVEMENT AT ONE END OF ITS PREDETERMINED STROKE AND ACTUATING MEANS ON SAID PISTON FOR OPENING SAID FIRST CHECK VALVE MEANS WHEN SAID PISTON IS AT SAID ONE END TO PERMIT FLUID FLOW FROM SAID POSITIONING MEANS TO SAID ADJUSTABLE VALVE MEANS IN SAID FIRST PARALLEL FLUID CONDUIT, AND (IV) A SECOND STOP MEANS MOUNTED IN SAID CYLINDER FOR ARRESTING THE MOVEMENT OF SAID PISTON AT THE OTHER END OF SAID PREDETERMINED STROKE AND MEANS IN SAID CYLINDER FOR OPENING SAID THIRD CHECK VALVE MEANS TO PERMIT FLUID FLOW FROM SAID ADJUSTABLE VALVE MEANS TO SAID POSITIONING MEANS IN SAID SECOND PARALLEL FLUID CONDUIT.