Modern pulleys are made of rolled shells with flexible end disks and locking assemblies.
Early pulley engineering was developed in Australia by Josef Sitzwohl[1] in 1948 and later by Helmuth Lange[2] and Walter Schmoltzi[3] in Germany.
Pulleys are made up of several components including the shell, end disk, hub, shaft and locking assembly.
The locking assembly may also be replaced with a hub and bushing on lower tension pulleys.
Pulley manufacturers in East Germany (DDR) in 1962 included Zemag, Lauchhammer, and Köthen.