The speed reducer upper on the main machine makes central axis rotate through shaft coupling and roller hanger rotates with central axis and rollers on the hanger roll around the inside of ring.

The casing hanger provides a means of ensuring that the string is correctly located and generally incorporates a sealing device or system to isolate the casing annulus from upper wellhead components.

A limit latch is placed inside the upper part of the lock body, and a hanger column corresponding to the limit latch is placed on one side of the rotary disc of the rotary claw.