Fig. 1

Schematic for Pre-sliding (A, B) According to the FNS operation guide, the handle at the red arrow is screwed to the end clockwise, retaining the maximum sliding distance (20 mm), at this time, the effective length of the FNS is 90 mm (C, D) The handle is screwed to the end clockwise and then unscrewed counterclockwise by a distance of about 10 mm (red arrow), at this time, the sliding distance is retained as 10 mm, and the effective length of the FNS is 80 mm (E, F) The handle is screwed to the end clockwise and then unscrewed counterclockwise by a distance of about 15 mm (red arrow), which is the maximum pre-sliding distance, at this time, the sliding distance is retained as 5 mm, and the effective length of the FNS is 75 mm G, H Schematic before (G) and after(H) pre-sliding, pre-sliding occurs by rotating the nut (white arrow), N represents the length of the FNS before pre-slip, X represents the pre-slip distance, and (N-X) represents the length of the FNS after pre-sliding