Piston ring construction

Claim 1

A CAST-IRON PISTON RING WITH FLAT AXIALLY DISPOSED TOP AND BOTTOM SURFACES, A RADIALLY INWARDLY DISPOSED INNER SURFACE AND A RADIALLY OUTWARDLY DISPOSED OUTER SEALING SURFACE, SAID RING BEING SPLIT TO DEFINE OPPOSING ENDS AND NORMALLY SET OUT OF ROUND AND WITH ITS ENDS IN SPACED RELATIONSHIP AND DEFINING A FREE GAP, SAID RING HAVING A RADIALLY OUTWARDLY OPENING CHANNEL IN ITS OUTER SURFACE INTERMEDIATE THE SIDES THEREOF, A WEAR RECEIVING INSERT COEXTENSIVE WITH AND FIXED IN THE CHANNEL, SAID INSERT HAVING A FLAT RADIALLY OUTWARDLY DISPOSED WEAR RECEIVING SURFACE FLUSH WITH SAID SEALING SURFACE, SAID INSERT OCCURRING RADIALLY OUTWARD OF THE CENTRAL CROSS-SECTIONAL AXIS OF THE RING WHEREBY SAID INSERT IS TENSIONED WHEN THE RING IS COMPRESSED TO CLOSE THE FREE GAP AND SERVES TO YIELDINGLY URGE THE RING OPEN TOWARDS ITS SET POSITION, SAID INSERT BEING ESTABLISHED OF MOLYBDENUM WIRE STOCK HAVING GREATER TENSILE STRENGTH AND ELASTICITY THAN CAST IRON.