1b and 1c the tubular bottom wedge 46 is fully retracted within the annular pocket 48 and consequently as the top wedge assembly 40 is driven into engagement with the slip anchor 32 the anchor slip 32 is displaced radially outwardly as the spreader cones engage and slip along the sloping cam surfaces 32c 32d respectively the lower cone 44 is blocked against further downward movement relative to the slip carrier by the stop ring 20 referring now in particular to fig1 b the hydraulic actuator assembly 30 includes an annular force transmitting setting piston 50 connected to a tubular link portion 52 by a threaded union t the inner piston bore 50a is sealed against the external cylindrical surface 12e of the mandrel by an internal o ring seal s the piston 50 is mounted for slideable movement along the packer mandrel surface 12e and is also disposed in slideable sealing engagement against the internal cylindrical bore 54 of a force transmitting setting cylinder 56 the setting cylinder 56 has an annular head portion 56h which rides in sealing engagement against the external mandrel surface 12e with the interface being sealed by an internal o ring seal s the annulus 58 between the setting cylinder bore 54 and external mandrel.