| 摘要 |
PROBLEM TO BE SOLVED: To provide a bolt capable of preventing fastening trouble due to rust.SOLUTION: A hook bolt has a screw thread shape having flat parts 7 to increase space amounts 13 in fitting, on a side of a thread part of a round screw on which no load is imposed. Since the hook bolt is a round screw the base screw shape of which conforms to a DIN Standard being a German Industrial Standard, and the space in fitting is large even when the bolt has rusted, influence of rust on the fitting can be reduced, and fastening trouble due to the rust can be prevented. |
