| 摘要 |
PROBLEM TO BE SOLVED: To prevent buckling of a screw part of a jack bolt and damage to a screw thread.SOLUTION: A jack bolt 10 comprises: a screw part 10a that is screwed into a screw hole 3a provided on a base floor 3 so that its screwing amount can be adjusted; and a stopper part 10b that is provided at the lower end of the screw part 10a and that has a diameter enlarged with respect to the screw part 10a. A stepped surface 10d is formed on the top surface of the stopper part 10b. The stepped surface 10d abuts on an undersurface 3b of the base floor 3. |
