Apparatus for measuring the intraocular or tonometric pressure of an eye

Claim 1

AN APPLANATION TONOMETER OF THE TYPE COMPRISING A BODY HAVING A PLANE MEASURING SURFACE ADAPTED TO BE APPLIED AGAINST THE CORNEA OF AN EYE AND FURTHER COMPRISING A MECHANISM FOR URGING THE SAID BODY AGAINST THE EYE, A FIRST LEVER CARRYING THE SAID BODY AND AN ACTUATING PORTION ON THE SAID FIRST LEVER CARRYING AN ANTIFRICTION BEARING, A SECOND LEVER CARRYING A WEIGHT AND HAVING AN ACTUATING MEMBER CONTACTING THE SAID ANTIFRICTION BEARING OF THE FIRST LEVER, A MOUNTING STRUCTURE FOR THE SAID SECOND LEVER ADAPTED FOR ROTATION ROUND A VERTICAL AXIS, AN AXIS OF THE SAID ANTIFRICTION BEARING SUBSTANTIAL COAXIAL WITH THE SAID VERTICAL AXIS, AN ADJUSTING SPINDLE FOR DISPLACEMENT OF AN ADJUSTING MEMBER AXIALLY ALONG THE SAID ADJUSTING SPINDLE, A DRIVING PIN ON THE SAID MOUNTING STRUCTURE ENGAGING THE SAID ADJUSTING MEMBER WHEREBY ROTATION OF THE SAID MOUNTING STRUCTURE AND SECOND LEVER ROUND THE SAID VERTICAL AXIS IS CAUSED UPON DISPLACEMENT OF THE SAID ADJUSTING MEMBER BY THE SAID SPINDLE, THE SAID WEIGHT AND THE SAID ACTUATING MEMBER EFFECTING THEREBY A ROTARY MOTION ROUND THE SAID VERTICAL AXIS AND THE SAID ANTIFRICTION BEARING RESPECTIVELY, AND THE EFFECTIVE LEVER ARM OF THE FORCE TRANSMITTED FROM THE SAID ACTUATING MEMBER TO THE SAID ANTIFRICTION BEARING AND FIRST LEVER RESPECTIVELY BEING CHANGED ON ROTATION OF THE SAID SECOND LEVER ROUND THE SAID VERTICAL AXIS FOR ACCORDINGLY VARYING THE PRESSURE BY WHICH THE SAID MEASURING SURFACE IS APPLIED AGAINST THE CORNEA, A LINEAR RELATION BETWEEN THE ROTATION OF THE SAID SPINDLE AND THE VARIATIONS OF THE SAID PRESSURE BEING OBTAINED BY THE SAID ADJUSTING MEMBER AXIALLY DISPLACEABLE ALONG THE SPINDLE, AND THE SAID MOUNTING STRUCTURE AND SECOND LEVER RESPECTIVELY ROTATABLE BY THE SAID ADJUSTING MEMBER.