Hydraulic piston devices cooperating with sliding potentiometers

Claim 1

AN HYDRAULIC PISTON DEVICE COOPERATING WITH A SLIDING POTENTIOMETER, COMPRISING A METALLIC CYLINDER PROVIDED WITH A CYLINDER BOTTOM AND A CYLINDER TOP, A PISTON SLIDABLY DISPOSED WITHIN SAID CYLINDER, A PISTON ROD ATTACHED TO SAID PISTON AND EXTENDING OUT FROM SAID CYLINDER THROUGH SAID CYLINDER TOP, SAID PISTON BEING PROVIDED WITH AN AXIALLY EXTENDING CENTER OPENING, SAID PISTON ROD BEING PROVIDED WITH AN AXIALLY EXTENDING BORE OPEN AT ONE END INTO SAID CENTER OPENING, CLOSED AT THE OTHER END AND HAVING AN INNER WALL, A POTENTIOMETER COIL COMPRISING A CORE AND AN OUTER COIL WINDING, SAID CORE BEING ATTACHED TO SAID CYLINDER BOTTOM AT THE CENTER THEREOF AND EXTENDING AXIALLY OF SAID CYLINDER THROUGH SAID CENTER OPENING INTO SAID AXIAL BORE IN SPACED RELTAIONSHIP TO SAID INNER WALL, SAID PISTON HAVING A CIRCUMFERENTIAL SIDE FACE, SAID PISTON BEING PROVIDED WITH A TRANSVERSE BORE EXTENDING FROM SAID SIDE FACE TO SAID CENTER OPENING A FIRST CONTACT MEMBER BEING SLIDABLY ARRANGED IN SAID TRANSVERSE BORE AT THE END THEREOF OPEN INTO SAID CENTER OPENING, A SECOND CONTACT MEMBER BEING SLIDABLY ARRANGED IN SAID TRANSVERSE BORE AT THE END THEREOF OPEN AT SAID SIDE FACE, A COMPRESSION SPRING BEING INSERTED BETWEEN SAID TWO CONTACT MEMBERS THEREBY PRESSING SAID FIRST CONTACT MEMAGAINST THE INNER FACE OF SAID CYLINDER.