CONNECTION KEY FOR CONCRETE CONDUIT FOR ELECTRIC WIRE UNDERGROUND MULTIPURPOSE DUCT

摘要

PROBLEM TO BE SOLVED: To provide a connection key being easy in connection operation for a concrete conduit for an electric wire underground multipurpose duct. SOLUTION: A connection key is arranged on the end surface of a concrete conduit for an electric wire multipurpose duct to be buried under the ground, and it includes a male key body 6 with a shearing tapered protrusion 5 at the abutting end face in front of the conduit connection face of the key main body having an anchoring constricted part 3 at the foundation end, and an inner tapered part 9 with the shearing tapered protrusion 5 loosely fitted at a predetermined distance (a) at an abutting end face in front of the conduit connection face of the key main body having an anchoring constricted part 7 at the foundation end, thus enabling the tip end of the shearing tapered protrusion 5 to be insertable at the position facing any part of the inner tapered part 9.