An externally & internally threaded tensioning nut(1) is turned on a stud(2) which attaches a cover to a nuclear reactor tank. The nut is turned by a striking roller(17) engaging its external circumference and rotated by a roller drive mechanism(19). The roller has external threads of the same profile as the external threads on the nut. No stress is exerted on the threads of the nut, and the nut can be unscrewed while the stud is being tightened onto the reactor vessel, thus reducing the time required.
展开▼
