Here we have a first Gen Medeco padlock. It was sold sometime in the mid 1970s and removed in 2005. I will show a tear down and the few parts. This padlock is in 6 pin Air keyway and is key retaining. It still works good after almost 30 years in service. Notice the armor all around and the anti drill pins in the top.
The disk on top rotates once it is open 90 deg and then lifts off. Then the locking bar can come out and then the cylinder can be removed for service.