An apparatus and method for forming a wellbore casing. An annular piston is displaced in the axial direction by pressurizing an annular piston chamber. The axial displacement of the piston radially expands a tubular member into contact with a preexisting tubular member. The radially expanded liner hanger...http://www.google.com/patents/US6568471?utm_source=gb-gplus-sharePatent US6568471 - Liner hanger
