Optical plug and mounting method thereof

An optical plug mounting method for mounting an optical plug on an optical fiber cable including a fiber, a core wire which covers the fiber, high tensile strength wires which cover the core wire and an outer sheath which covers the high tensile strength wires,

• wherein the optical plug includes:
• a tubular ferule which holds the fiber and the core wire of the optical fiber cable such that the fiber of the optical fiber cable is exposed from the distal end of the ferule;
• a tubular adapter housing in which the distal end of the ferule is inserted;
• a tubular plug body which includes a projecting portion which is inserted into the inside of the adapter housing and an extending portion in which a plurality of annular grooves are formed and is which is covered with the high tensile strength wires of the optical fiber cable;
• a compression coil spring which is formed in the inside of the projecting portion of the plug body and biases the ferule toward the adapter housing;
• a tubular compression bonding sleeve which includes a crimp portion which covers the extending portion of the plug body from above the high tensile strength wires of the optical fiber cable and a support portion provided at the proximal end side of the crimp portion;
• wherein a pair of dies having an cone-shaped insertion hole is used, the dies are opened, the annular grooves of the extending portion are disposed at the small-diameter side of the insertion hole and, thereafter, by closing the pair of dies, the diameter of the crimp portion is narrowed so that the crimp portion compression-bonds the high tensile strength wires to the extending portion of the plug body.