| 摘要 |
PROBLEM TO BE SOLVED: To safely maintain a large diameter bolt with excellent actuating efficiency by providing at least a pair of brushes which rotate in the mutually reverse direction and contact with different positions of the same bolt. SOLUTION: When a normally rotating brush 7 and a reversely rotating brush 8 are uniformly contacted with a bolt 9, since equal torques in the mutually inverse direction are applied to the bolt 9, the bolt 9 does not rotate. When the normally rotating brush 7 side is strongly pressed against the bolt 9, frictional force between the normally rotating brush 7 and the bolt 9 increases, and the bolt 8 reversely rotates. To the contrary, when the reversely rotating brush 8 is strongly pressed against the bolt 9, the bolt 9 normally rotates. When the normally rotating side is strongly pressed against it, maintenance is performed by the reversely rotating brush 8, and when the reversely rotating side is strongly pressed against it, the maintenance is performed by the normally rotating brush 7. |
