Piston ring assembly of flexible circumferentially compressible spring expander-spacer and piston rings

Claim 1

IN A COMPRESSIBLE AND EXPANSIVE NON-BOTTOMING TYPE OF PISTON RING ASSEMBLY DIAMETRICALLY AND AXIALLY DIMENSIONED TO BE RECEIVED IN A PISTON RING GROOVE WITH ITS INNER PERIPHERY SPACED FROM THE BOTTOM OF THE PISTON RING GROOVE WHEN HELD COMPRESSED IN SAID GROOVE BY THE WALL OF A CYLINDER FOR THE PISTON, A PAIR OF SPLIT ANNULAR RADIALLY EXPANSIBLE AND CONTRACTIBLE PISTON RINGS IN SAID PISTON RING ASSEMBLY EACH HAVING A PLAIN RADIAL FACE FOR SEALING CONTACT WITH ONE SIDE OF THE PISTON RING GROOVE, AND EACH HAVING AN OUTER PERIPHERAL FACE FOR SEALING CONTACT WITH THE WALL OF A CYLINDER, AN ANNULAR CORRUGATED CIRCUMFERENTIALLY EXPANSIBLE AND COMPRESSIBLE SPRING EXPANDER-SPACER CONTROL RING IN SAID PISTON RING ASSEMBLY HAVING OPPOSITELY DIRECTED HUMPS SOME OF WHICH ARE DIRECTED BETWEEN SAID PAIR OF PISTON RINGS TO ACT AS SPACERS, AND RELATIVELY RIGID AXIALLY EXTENDING CANTILEVER TYPE FINGERS FORMING A CONTINUATION OF, AND PROJECTING FROM, SOME OF SAID HUMPS ON SAID SPRING EXPANDER-SPACER CONTROL RING AND OFFSET RADIALLY INWARDLY FROM THE OUTER PERIPHERY OF SAID CONTROL RING AND OFFSET A LESSER DEGREE IN OPPOSITE AXIAL DIRECTIONS FROM SAID CONTROL RING TO ENGAGE AN INWARDLY FACING PERIPHERAL EDGE ON EACH OF SAID PAIR OF PISTON RINGS SO THAT WHEN SAID ASSEMBLY IS IN OPERATIVE POSITION, SAID CONTROL RING IS HELD COMPRESSED IN SAID PISTON RING GROOVE TO A MINIMUM DIAMETER GREATER THAN THE DIAMETER AT THE BOTTOM OF SAID PISTON RING GROOVE, THE IMPROVEMENT COMPRISING, (A) A PLURALITY OF RING ENGAGING SURFACES ON SAID AXIAL EXTENDING CANTILEVER TYPE FINGERS FOR DIRECTLY ENGAGING SAID INWARDLY FACING PERIPHERAL EDGE ON EACH OF SAID PAIR OF PISTON RINGS, SAID SURFACES FACING IN THE SAME DIRECTION ON TOP AND ON THE BOTTOM WITH RESPECT TO THE PORTION OF A PISTON RING IN CONTACT THEREWITH, AND SAID SURFACES BEING SPACED ALONG SAID CONTROL RING TO ENGAGE WITH SAID PAIR OF PISTON RINGS AT POINTS SPACED CIRCUMFERENTIALLY AROUND SAID PISTON RINGS IN AN ALTERNATING MANNER THEREBETWEEN, AND (B) MEANS FORMING SPACED RESILIENT PORTIONS IN SAID CONTROL RING BETWEEN SAID CANTILEVER TYPE FINGERS TO PROVIDE FLEXIBLITY FOR DISTORTION AXIALLY ALONG SAID CONTROL RING, SAID ANNULAR PISTON RINGS BEING DIMENSIONED DIAMETRICALLY AND IN WIDTH SO THAT WHEN SAID ASSEMBLY IS COMPRESSED TO SAID OPERATING CONDITION, SAID INWARDLY FACING PERIPHERAL EDGES PRESS RADIALLY INWARDLY AGAINST SAID ALTERNATELY ARRANGED RING ENGAGING SURFACES ON SAID CANTILEVER TYPE FINGERS WITH A FORCE SUFFICIENT TO CAUSE CIRCUMFERENTIAL COMPRESSION IN SAID CONTROL RING BY RADIAL INWARD DISPLACEMENT OF SAID FINGERS ON OPPOSITE SIDES OF SAID CONTROL RING AND TWISTING IN OPPOSITE DIRECTIONS AXIALLY THEREALONG, CAUSING THE HUMPS ADJACENT SAID CANTILEVER TYPE FINGERS WHICH ACT AS SPACERS BETWEEN SAID PISTON RINGS TO EXERT MORE AXIAL PRESSURE ON THE RADIAL FACE OF ONE OF SAID PISTON RINGS THAN ON THE OTHER, OPPOSITELY TOP AND BOTTOM, CIRCUMFERENTIALLY AROUND SAID CONTROL RING, TO URGE EACH OF SAID PISTON RINGS INTO SEALING ENGAGEMENT WITH A SIDE OF THE PISTON RING GROOVE WITH RESILIENT AXIALLY DIRECTED FORCES WHICH ARE LESS THAN, BUT PROPORTIONAL TO, THE RADIAL FORCES EXERTED ON SAID PISTON RINGS BY SAID CONTROL RING THROUGH SAID CANTILEVER TYPE FINGERS.