Design Features:
▋Joining the travelling block and the hook together reduces overall length to satisfy the requirements of a top drive.
▋The shafts of travelling block are forged with alloy steel and provided with a lubrication hole of bearing for one sheave.
▋The grooves of sheave are intermediate frequency quenched so as to improve the surface hardness and prolong the service
life of wire rope.
▋The sheaves are equipped with double-row conic roller bearings. Each bearing has its own lubrication channel.
▋There is a reliable safety device at the hook.
▋The primary-load-carrying parts of hook are subject to NDE test.
▋The hook block assembly conforms to API Spec. 8A /8C and are stamped with API monogram.
Specifications of Hook/Block Assembly:
| Model | YG90 | YG135 | YG170 | YG450 | |
| Max. hook load | kN | 900 | 1350 | 1700 | 4500 |
| O.D.of sheaves | mm (in) | 762(30) | 915(36) | 915(36) | 1524(60) |
| Number of sheaves | 4 | 4 | 5 | 6 | |
| Diameter of wire line | mm (in) | 26(1) | 26(1) | 29 (11/8) | 38 (11/2) |
| Major-hook opening | mm (in) | 155（61/16） | 165（61/2） | 180（7） | 220（85/8） |
| Major-hook Dia. | mm (in) | 116（41/2） | 140（51/2） | 150（6） | 180（7） |
| Minor-hook Dia. | mm (in) | 80（31/4） | 90（31/2） | 90（31/2） | 120（43/4） |
| Overall dimension (L×W×H) | mm | 2908×806×533 | 3195×960×616 | 3294×960×713 | 4887×1600×880 |
| Weight | kg | 2850 | 3590 | 4585 | 12530 |