This design then is replaced

Early forms of linear motion bearings, is placed in a row of pry plate under a row of wooden poles. Modern linear motion bearings is using the same principle, but sometimes a ball instead of roller. The simplest is the rotation of the bearing sleeve bearing, it is just a between wheel and axle bushing. This design then is replaced by rolling bearing, is to use a lot of cylindrical roller instead of bushing, each as a single wheel roller.