| 摘要 |
PURPOSE: A double protecting cap for a bolt and a nut is provided to prevent a natural damage of covering caused by contracting-hardening two caps and a bolt and a nut becoming rusty by controlling humidity without accommodating grease in a fiber packing. CONSTITUTION: A double protecting cap for a bolt and a nut comprises a bolt, a nut, an outer cap(30), and an inner cap(40). Fitting recessed portions(30',30'') are formed in the inside of the outer cap in a longitudinal direction at a constant interval. Protrusion piece(40') is fitted and joined to the recessed portions. Triangular recessed portion are formed in each end parts of fixing pieces protruded from the boundary of the inner bottom surface of the inner cap. |
