Optical connector having means for positioning tilted convex surface of ferrule

An optical connector for connecting an optical fiber protruding from a cord tube through a buffer tube to an adaptor, the optical connector comprising:

• a ferrule composed of a capillary and a flange integrated with the capillary, the capillary axially guiding therethrough the optical fiber which protrudes from the buffer tube and having a tip end portion polished into a tilted convex surface for Positioning in a predetermined registered position and a rear end portion which is axially spaced from the tip end portion, the flange being fixed to the rear end portion of the capillary and having a key projection engageable with a key recess of the adaptor in a circumferential position therein such that a tilt direction of the tilted convex surface of the ferrule is positioned in the predetermined registered position when the key projection is in the circumferential position to thereby determine a circumferential position of the ferrule, the flange having a guide sleeve extending rearwardly from the rear end portion of the capillary for receiving therein the buffer tube;
• a plug frame having a front sleeve for accommodating therein the flange of the ferrule and a rear sleeve extending axially rearwardly from the front sleeve to guide therethrough the buffer tube;
• a spring member interposed between the flange of the ferrule and the front sleeve of the plug frame for urging the capillary axially forward;
• a clamp ring engaged around an outer periphery of the rear sleeve of the plug frame and being engaged with a tip end portion of the cord tube to thereby firmly connect the rear sleeve and the cord tube with each other;
• and
• a coupling nut mounted around an outer periphery of the plug frame and being connected to the adaptor to thereby couple the plug frame to the adaptor.