The ring is to disconect the front drive so you can rotate the back gear lever to drive slowly. It disconnects a plunger into the bull gear by rotating a ring with a ramp on. There is a screw with a screw driver slot, on my one to stop the ring rotating on its own as you don't want to connect both at the same time, broken gears or other damage.

David
Edited By David George 1 on 23/01/2020 20:06:54
Edited By David George 1 on 23/01/2020 20:09:50