COUPLING DEVICE AND COMPOSITE BOLT

摘要

PROBLEM TO BE SOLVED: To provide a new type of coupling device having an excellent usability at job site and a new type of composite bolt to be used for the coupling device. SOLUTION: The composite bolt 2 is constructed by friction pressure welding wherein a fixed shaft 4 of aluminium is combined to a bolt main body 3 of iron or steel and wherein further the fixed shaft 4 of the composite bolt 2 is fusion welded or pressure welded to a base metal 1 of aluminium.