Sicherungsmutter (f)

check nut (n)

Turn the two eccentric bolts anticlockwise slightly and tighten the lock nuts by hand.

First we turn the two eccentric bolts anticlockwise slightly then we tighten both counter nuts, or lock nuts, by hand.

The countersinks show that this is the top of the Cover Plate and the positioning of the holes for the lock nuts ensures it is fitted correctly.