Hydraulic cap and pressure ring seal

Claim 1

SEALING MEANS FOR PRECLUDING THE LEAKAGE OF FLUID PASS TWO RELATIVELY RECIPROCABLE MEMBERS HAVING MATING CYLINDRIC SURFACES, ONE OF WHICH SURFACES HAS AN ANNULAR GROOVE SUBSTANTIALLY RECTANGULAR IN CROSS SECTION CONFRONTING THE OTHER SURFACE AND IN WHICH GROOVE THE SEALING MEANS ARE SEATED, SAID SEALING MEANS COMPRISING: A CONTINUOUS, ANNULAR, FLEXIBLE OUTER SEALING RING HAVING A LOW COEFFICIENT OF FRICTION, SAID OUTER SEALING RING BEING CONCAVE ON ITS INNER FACE AND HAVING A FLEXIBLY THIN CENTRAL BASE, THE SURFACES OF THE CONCAVITY OF SAID OUTER RING INCLUDING A BROAD BASE PLANAR SURFACE AND BEING RECTILINEAR IN ALL CROSS SECTIONAL STATIONS, AND SAID OUTER RING BEING SUBSTANTIALLY AS WIDE AS, AND RECEIVABLE IN, THE AFOREMENTIONED GROOVE WITH ITS OUTER FACE ADAPTED TO SLIDABLY ENGAGE THE SURFACE OF THE OTHER ONE OF THE RELATIVELY RECIPROCABLE MEMBERS; AND AN ANNULAR, RESILIENT, DEFORMABLE PRESSURE RING NESTED BELOW SAID OUTER RING FOR TIGHTLY URGING THE LATTER INTO SEALING ENGAGEMENT WITH THE SURFACE WHICH IT CONTACTS, THE OUTER MARGINAL-PERIPHERAL SURFACES OF SAID PRESSURE RING BEING RECTILINEAR IN ALL CROSS SECTIONAL STATIONS TO MATCH IN ITS RELAXED STATE THE CONFRONTING SURFACES OF THE CONCAVITY IN SAID OUTER RING AND BE IN INTERFITTING CONTACT THEREWITH AT ALL TIMES, THE RESILIENCY OF SAID PRESSURE RING UNDER COMPRESSION EXERTING A SUBSTANTIALLY UNIFORM PRESSURE AGAINST ALL PORTIONS OF THE PLANAR SURFACE OF SAID OUTER RING, THE TOTAL RADIAL THICKNESS OF SAID OUTER RING AND PRESSURE RING, WHEN RELAXED, BEING GREATER THAN THE DEPTH OF THE GROOVE SO THAT WITH SAID SEALING MEANS MOUNTED IN THE GROOVE, SAID PRESSURE RING PRESSURES SAID OUTER RING, THE TWO RINGS AFORESAID THEN HAVING THEIR GREATEST WIDTH SUBSTANTIALLY EQUAL TO THE GROOVE WIDTH WHEREBY WHEN THE RECIPROCATING MEMBERS ARE ASSEMBLED WITH SAID SEAL IN THE GROOVE, SAID PRESSURE RING WILL BE DEFORMED SO THAT AT ALL TIMES IT PRESSURES SAID OUTER RING AND THE FULL WIDTH OF SAID OUTER RING IS UTILIZED TO PROVIDE AN EFFECTIVE SEAL IN WHICH SAID PRESSURE RING IS IN INTERFITTING CONTACT WITH SAID RECTILINEARLY CONGRUENT CHANNEL OF SAID OUTER RING TO PREVENT EXTRUSION OF SAID PRESSURE RING INTO A RIBBON BETWEEN SAID MATING CYLINDRIC SURFACES FROM LOW TO VERY HIGH FLUID PRESSURES.