Twist lock check valve

Claim 1

ATTACHMENT STRUCTURE COMPRISING: A PLATE MEMBER HAVING INNER AND OUTER SIDES AND AN OPENING THERETHROUGH, SAID PLATE DEFINING RADIALLY OUTWARDLY EXTENDING NOTCHES EXTENDING FROM SAID OPENING INTO SAID PLATE THE OPPOSED SIDES OF SAID NOTCHES BEING DEFINED BY SUBSTANTIALLY RADIALLY EXTENDING WALLS OF SAID PLATE; A RADIALLY EXTENDING TAB PORTION NORMAL TO SAID INNER SAID AT ONE OF SAID RADIALLY EXTENDING WALLS OF EACH OF SAID NOTCHES; A RAMP MEANS BETWEEN SAID NOTCHES COMPRISING A PLANAR SURFACE DEPENDING FROM SAID INNER SIDE AND PARTLY DEFINING SAID OPENING AND DISPOSED AT AN ANGLE TO SAID PLATE, SAID RAMP MEANS EXTENDING TOWARD SAID TAB AND TERMINATING IN A SHEAR EDGE, SAID SHEAR EDGE AND SAID TAB PORTION BEING SPACED A DISTANCE SUBSTANTIALLY EQUAL TO THE WIDTH OF SAID NOTCHES; A GENERALLY TUBULAR MEMBER SUBSTANTIALLY EQUAL IN DIAMETER WITH SAID OPENING, SAID TUBULAR MEMBER HAVING AN ANNULAR EXTERNAL STEPPED SHOULDER WITH THE SMALLER PORTION THEREOF OF A DIAMETER EQUAL TO A CIRCLE ENCLOSING PERIPHERAL PORTIONS OF SAID NOTCHES, SAID TUBULAR MEMBER HAVING AT LEAST ONE PORJECTING FINGER OF A DIMENSION TO BE RECEIVED BY SAID NOTCHES, SAID FINGER BEING INWARDLY SPACED FROM SAID STEPPED SHOULDER A DISTANCE SUBSTANTIALLY EQUAL TO A CROSS SECTION OF SAID PLATE MEMBER; AND A RING OF RESILIENT SEALING MATERIAL FITTER TO SAID SMALLER PORTION UNDER SAID LARGER PORTION ABOVE AND OUTWARD OF SAID FINGERS, SAID SEALING MATERIAL OF A CROSS SECTIONAL DIMENSION TO EXTEND INTO AN AREA BETWEEN SAID SMALLER PORTION SUCH THAT SAID RING WILL BE COMPRESSED BETWEEN SAID PLATE MEMBER AND THE LARGER STEPPED SHOULDER PORTION OF SAID TUBULAR MEMBER ALONG THE ENTIRE SURFACE OF SAID RING, SAID RING BEING RETAINED FROM BLOWN-IN BY SAID SMALLER STEPPED SHOULDER PORTION BEING INWARD THEREOF.