Abstract

A hanger assembly 10 for suspending an inner pipe string 32 within an outer casing 16 from a particular location therein. The hanger assembly includes a hanger body 30 and an expandable locking assembly 46 comprised of a plurality of latching fingers 77 secured at their lower ends about the hanger body by a split retainer ring 48 which permits limited pivotal movement of the latching fingers about their lower ends. Each latching finger 47 is provided with a hook surface 71 adjacent its upper end adapted to engage an upward facing abutment 20 on the inner profile of the outer casing. The free ends of the latching fingers are urged outwardly by a circular spring 58. The retainer 48 and locking assembly 46 are secured to the hanger body 30 by a connecting shear ring 55 which restrains relative axial movement of the locking assembly on the hanger body until the latching fingers hook on the inner profile of the outer casing whereby the shear ring 55 is parted by a predetermined weight of the inner pipe string and the hanger body 30 slides downward to lock the fingers 47 in latched relation with the outer casing 16. By uplifting the hanger 30, cooperating cam surfaces 72, 75, 19, 26 on the fingers 47 and outer casing 16 permit extraction of the inner pipe string 32 if desired.