Abstract: A coupler 10 for pressure conduits 12a-d comprises movable components 22, 26 selectively engageable with or disengageable from fixed components 34 to provide disconnectable sealed pressure connections therewith, the moveable components 22 being acted upon by a primary actuator comprising a bearing plate 52, a thrust nut 50 and a threaded drive spindle 44. Spindle 44 is mounted in an end cap 46 normally held fixed relative to the fixed components by collet fingers 66 but which is disengageable from a connector body 14 upon withdrawal of a retainer sleeve (70, FIG. 8) so as to provide secondary actuation of the movable components 22, 26 independently of the primary actuator 44, 50, 52.