Abstract: A linear actuator includes a spindle, a main nut, and a safety nut which cooperates with the main nut. The flank of the safety nut closest to the load supported by the spindle is made steep, i.e., forms an acute angle of between about 20 to 30 degrees with its longitudinal axis, thereby providing a great frictional force by engagement with the threads of the spindle in the event that the main nut fails. The great frictional force is brought about because the threads of the spindle, exclusively with the outer edge, become in linear engagement with the steep flank on the safety nut.

Abstract: A linear actuator of the type whose function is based on a spindle (3) and a main nut (4), is provided with a safety nut (7) in connection with the main nut. The flank (9) of the safety nut closest to the load is made steep, i.e. forms an acute angle with its longitudinal axis, thereby providing a great frictional force by engagement with the threads of the spindle in the event that the main nut fails. The great frictional force is brought about in that the threads of the spindle, exclusively with the outer edge, get into linear engagement with the steep flank on the safety nut.