What is the difference between a pull-out screw and an expansion screw

The expansion bolt is wrapped with a ring cylinder, which has a gap and is used to make a hole in the wall. Put the expansion bolt into this hole and squeeze the cylinder open when tightening the bolt. This stuck the bolt in the hole. Play a fixed role. Pull the screw, there is a section of the nut structure can be deformed, the screw in tightening the nut with the pull of the nut deformation, while the nut riveted on the workpiece, after the nut is fixed on the workpiece.