A connector for coupling pipe sections which may be either aligned or misaligned axially, the connector having a male fitting, a female fitting which mates with the male fitting and a retaining means which can be connected to the female fitting to hold the male fitting in place against the female fitting. In one embodiment, the retaining means comprises a hammer nut which has a retaining surface. The retaining surface of the hammer nut contacts a rear surface of a first one of the flanges for urging this flange forward. The hammer nut has threads which are complementary to a set of threads on the second flange. When the hammer nut is threaded onto the second flange, the first and second flanges are pulled together. The retaining surface of the hammer nut and the rear surface of the first flange have complementary spherical shapes so that the hammer nut can rotate and swivel with respect to the flange. The hammer nut can therefore be aligned with the second flange and threaded onto it, even though the first and second flanges are misaligned.