Connector and mating connector and combination thereof

摘要

A plug connector comprises a fitting portion to be fitted with another fitting portion of a receptacle connector. In an outer peripheral surface of the fitting portion, an engagement depression is formed. The engagement depression is depressed in a radial direction of the plug connector. A coupling member surrounds the outer peripheral surface of the fitting portion with a predetermined gap kept therebetween. The coupling member is pressed forwards in an axial direction of the plug connector by a coil spring. The receptacle connector further comprises a spring portion, on the free end of which an engagement projection is provided. The engagement projection projects inwardly in the radial direction. The fitting portion of the receptacle connector has a thickness which is substantially equal to the predetermined gap provided for the plug connector. When the engagement projection is accommodated in the engagement depression, the fitting portion of the receptacle connector is fitly received within the predetermined gap between the fitting portion and the coupling member so that the coupling of the plug and the receptacle connectors is locked.