Adjustable riser for sprinkler systems

Claim 1

A RISER FOR USE IN AN UNDERGROUND SPRINKLER SYSTEM COMPRISING A LOWER TUBULAR RISER SECTION HAVING AN OPEN UPPER END, AN UPPER TUBULAR RISER SECTION TELESCOPED IN SAID LOWER SECTION FOR AXIAL AND ROTATIONAL MOVEMENT, MEANS ON THE UPPER END OF SAID LOWER SECTION IN SEALING ENGAGEMENT WITH THE EXTERNAL SURFACE OF THE TELESCOPED PORTION OF SAID UPPER SECTION, AND A UNITARY SECURING AND SEALING ASSEMBLY MEANS FOR SEALING SAID UPPER SECTION IN SAID LOWER SECTION AND FOR INTERENGAGING SAID UPPER AND LOWER SECTIONS TO RESTRAIN RELATIVE AXIAL MOVEMENT BETWEEN SAID SECTIONS COMPRISING A HOLLOW POST HAVING A LOWER RADIAL FLANGE, SAID FLANGE BEING KEYED IN SAID LOWER SECTION FOR AXIAL AND NONROTATABLE MOVEMENT THEREWITH, A RESILIENT PACKING RING DISPOSED ON SAID POST ABOVE SAID FLANGE, SAID RING FITTING CLOSELY AND SLIDABLY IN SAID LOWER SECTION AND IN FRICTIONAL CONTACT THEREWITH AND BEING RADIALLY EXPANSIBLE IN RESPONSE TO AXIAL COMPRESSION, EXTERNAL THREAD MEANS ON THE UPPER END OF SAID POST ABOVE SAID RING, THE OUTER DIAMETER OF SAID POST BETWEEN SAID THREADS AND SAID FLANGE BEING LESS THAN EITHER THE OUTER DIAMETER OF THE THREADED PORTION OR THE THE OUTER DIAMETER OF SAID FLANGE, AND A RETAINING RING HAVING AN INNER DIAMETER LESS THAN THE OUTER DIAMETER OF SAID THREADS OR SAID FLANGE MOUNTED ON SAID POST ABOVE SAID PACKING RING AND BELOW SAID THREAD MEANS FOR RETAINING SAID PACKING RING ON SAID POST, THE LOWER END OF SAID UPPER SECTION HAVING INTERNAL THREADED MEANS MATING WITH SAID THREAD MEANS OF SAID POST AND A RADIAL SHOULDER ON THE LOWER END OF SAID UPPER SECTION ENGAGEABLE WITH SAID RETAINING RING WHEN SAID UPPER SECTION IS THREADEDLY ENGAGED WITH SAID POST TO MOVE SAID RETAINING RING ON SAID POST AGAINST SAID PACKING RING AND SAID PACKING RING AGAINST SAID LOWER RADIAL FLANGE AND AXIALLY COMPRESS SAID PACKING RING THEREBY RADIALLY EXPANDING SAID PACKING RING INTO SEALING ENGAGEMENT WITH SAID POST AND SAID LOWER TUBULAR RISER SECTION.