Well swab assembly

Claim 1

A WELL SWAB FOR SWABBING THE INTERNAL WALLS OF, AND LIFTING FLUID FROM, OIL WELL TUBING OR THE LIKE COMPRISING, IN COMBINATION WITH SAID TUBING: A METALLIC, GENERALLY CYLINDRICAL MEMBER; AN ANNULAR SLEEVE OF RESILIENT MATERIAL AROUND SAID METALLIC, GENERALLY CYLINDRICAL MEMBER AND BONDED THERETO, SAID SLEEVE HAVING A LOAD-CARRYING PORTION OF LESSER OUTSIDE DIAMETER THAN THE INTERNAL DIAMETER OF SAID TUBING AND EXTENDING FROM ONE END OF SAID CYLINDRICAL MEMBER OVER A MOJOR PORTION OF THE LENGTH THEREOF AND TERMINATING IN AN ABRUPT, ANNULAR SHOULDER, THE LENGTH OF SAID LOAD-CARRYING PORTION BEING GREATER THAN THE RADIAL THICKNESS THEREOF, AND SAID SLEEVE FURTHER HAVING A LIP-SUPPORTING PORTION OF SMALLER RADIAL THICKNESS THAN SAID LOAD-CARRYING PORTION AND EXTENDING AXIALLY ALONG SAID CYLINDRICAL MEMBER FROM SAID LOAD-CARRYING PORTION TOWARD THE OTHER END OF SAID CYLINDRICAL MEMBER; AND AN ANNULAR, FLEXIBLE LIP OF RESILIENT MATERIAL FORMED INTEGRALLY WITH SAID LIP-SUPPORTING PORTION AND EXTENDING OUTWARDLY THEREFROM TOWARD THE INTERNAL WALLS OF SAID TUBING, SAID FLEXIBLE LIP BEING DIMENSIONED TO SEALINGLY ENGAGE THE INTERNAL WALLS OF SAID TUBING WHEN SAID LIP OCCUPIES A PLANE EXTENDING NORMAL TO THE AXIS OF SAID TUBING AND BEING SPACED FROM THE ANNULAR SHOULDER OF SAID LOAD-CARRYING PORTION BY A DISTANCE SUFFICIENTLY SMALL TO PERMIT SAID LIP TO SEALINGLY ENGAGE THE INTERNAL WALLS OF SAID TUBING WHEN SAID FLEXIBLE LIP IS FLEXED BY A HYDROSATIC PRESSURE INTO ABUTTING CONTACT WITH SAID SHOULDER.