Non-jamming apex seal

Claim 1

A SEALING ARRANGEMENT FOR THE WORKING CHAMBERS OF A ROTARY MECHANISM HAVING AN OUTER BODY WITH AXIALLYSPACED END WALLS INTERCONNECTED WITH A PERIPHERAL WALL FORMING A CAVITY WITH SAID CAVITY HAVING A MULTI-LOBED PROFILE; AN INNER ROTOR HAVING AXIALLY-SPACED END FACES MOUNTED WITHIN SAID CAVITY, SAID ROTOR HAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED PORTIONS FOR ENGAGEMENT WITH THE INNER SURFACE OF SAID PERIPHERAL WALL WHEREUPON, DURING RELATIVE ROTATION OF SAID OUTER BODY AND INNER ROTOR, WORKING CHAMBERS OF VARIABLE VOLUME ARE FORMED; SAID SEALING ARRANGEMENT COMPRISING A SEAL MEMBER MOUNTED IN A GROOVE IN AT LEAST ONE OF SAID CIRCUMFERENTIALLY SPACED PORTIONS FOR RADIAL MOVEMENT WITH RESPECT TO SAID GROOVE AND HAVING A SINGLE APEX PORTION FOR SEALING ENGAGEMENT WITH THE INNER SURFACE OF SAID OUTER BODY PERIPHERAL WALL AND THE WIDTH OF SAID GROOVE INWARDLY OF ITS OUTER EDGE BEING AT LEAST AS GREAT AS THAT AT THE GROOVE OUTER EDGE, SAID SEAL MEMBER HAVING DIAGONALLY OPPOSED PORTIONS AT ITS RADIALLY INWARD AND OUTWARD REGIONS FOR ENGAGEMENT WITH THE SIDE WALLS OF SAID GROOVE WHEN SAID SEAL MEMBER IS IN A MAXIMUM TILTED POSITION RELATIVE TO SAID GROOVE SIDE WALLS AND THE CONFIGURATION OF SAID SEAL MEMBER AND SAID GROOVE BEING RELATED TO ONE ANOTHER FOR PERMITTING SLIDING ENGAGEMENT OF SAID SEAL MEMBER WITH SAID GROOVE SIDE WALLS AND FOR PREVENTING THE CORNERS OF SAID SEAL MEMBER FROM DIGGING INTO SAID GROOVE SIDE WALLS AND THE CORNERS OF SAID GROOVE FROM DIGGING INTO THE SEAL MEMBER SIDE WALLS WHEN SAID SEAL MEMBER IS IN A MAXIMUM TILTED POSITION SUCH THAT SAID SEAL MEMBER CAN SLIDE RADIALLY INWARDLY INTO THE GROOVE WITHOUT ACCOMPANYING SUBSTANTIAL TILTING MOVEMENT OF SAID SEAL MEMBER TOWARD A POSITION PARALLEL TO SAID GROOVE SIDE WALLS.