The stop prevents the acme screw thread unscrewing clear of the screw jack housing. It is a washer pinned at the acme screw end(opposite the attachment side ）that blocks the screw translation when reaching the relative stop.
The acme screw length is defined to allow, under normal use, at the maximum extended position, 20mm of additional stroke(safety extra-stroke). If the mechanical stop reaches accidentally the relative stop, it is necessary to check the screw jacks components to verify possible damages.
Bearing lock nuts require a positive locking action, similar to castellated nuts, to lock in place. Bearing lock nuts are mated with bearing lock washers to achieve locking capabilities. The machined grooves in the face of the nut provide a mating surface for the tangs of the lock washer to fold into, locking both components in place.
