The crown block consists of crown basement, fast-line sheave, dead-line sheave, main sheave, sand-line sheave, drilling line protector and sheaves for hydraulic and air winch, bumper wood for the Crown-O-Matic and guardrail. It’s designed with closed type and open type. The traveling system is divided into 7×6, 6×5, 5×4, and 4×3, which fit to Φ7/8”～Φ1 1/2” drilling lines. The sheave groove conforms to the requirements of API RP 9B. The sheave groove surface is processed with a quenching treatment. The bearing adopts centralized lubrication for convenient operation.