Hydraulic load cell

Claim 1

A LOAD CELL COMPRISING, IN COMBINATION: (A) A BASE STRUCTURE INCLUDING AN UPSTANDING PISTON PORTION; (B) A LOAD RECEIVING STRUCTURE INCLUDING (1) AN UPPER PORTION PRESENTING A LOAD RECEIVING SURFACE, AND (2) A CYLINDRICAL SKIRT PORTION DEPENDING FROM SAID UPPER PORTION AND TELESCOPICALLY AND COAXIALLY RECEIVING SAID PISTON PORTION WITH AN ANNULAR SPACE THEREBETWEEN; (C) A RELATIVELY THIN FLEXIBLE DIAPHRAGM OF FLUID IMPERVIOUS MATERIAL SEALED TO SAID CYLINDER PORTION AND OVERLYING SAID PISTON PORTION TO FORM A FLUID PRESSURE CHAMBER BETWEEN IT AND SAID UPPER PORTION, (1) AN ANNULAR FOLD OF SAID DIAPHRAGM INTERLYING AN UPPER PORTION OF SAID ANNULAR SPACE; (D) A RING SURROUNDING SAID PISTON PORTION AND PRESENTING AN ANNULAR SUPPORT SURFACE UNDERLYING SAID ANNULAR SPACE; AND (E) A PLURALITY OF BALLS, (1) ARRANGED BALL TO BALL ON SAID SUPPORT SURFACE IN A SINGLE CLOSED CIRCUMFERENTIAL ROW EXTENDING AROUND SAID PISTON PORTION IN SAID ANNULAR SPACE, AND, (2) ROLLABLY ENGAGING THE ADJACENT CYLINDRICAL WALLS OF SAID PORTIONS TO GUIDE THEM IN THEIR TELESCOPIC MOVEMENT AND ALLOW RELATIVE TILTING MOVEMENT THEREBETWEEN; (F) SAID CYLINDRICAL SKIRT EXTENDING DOWNWARDLY BEYOND SAID ANNULAR SPACE AND SEALINGLY ENGAGING THE OUTER PERIPHERAL SURFACE OF SAID RING MEMBER, WHEREBY TO PREVENT THE ENTRY OF DUST INTO SAID ANNULAR SPACE; (G) SAID RING MEMBER BEING FORMED OF A RESILIENT MATERIAL SO AS TO YIELDINGLY ALLOW THE AFOREDESCRIBED RELATIVE TILTING MOVEMENT OF SAID PISTON AND CYLINDER PORTIONS AND SO AS TO YIELD DOWNWARDLY UPON COLLAPSING TELESCOPIC MOVEMENT OF SAID PORTIONS TO ALLOW SAID BALLS TO ROLL RATHER THAN SKID ON SAID CYLINDRICAL WALLS; AND (H) SEPARATE MEMBERS RIGID WITH SAID PISTON AND SAID CYLINDER PORTIONS, RESPECTIVELY, AND PROJECTING RADIALLY THEREFROM INTO SAID ANNULAR SPACE BETWEEN ADJACENT BALLS TO RESIST RELATIVE ROTATION BETWEEN SAID PORTIONS AND THEREBY PREVENT RUPTURE OF SAID DIAPHRAGM.