Hook Blocks for mobile cranes are critical lifting attachments combining a hook, swivel, and multiple sheaves (pulleys) to lift heavy loads. They increase crane capacity via mechanical advantage (parts of line), commonly used with wire rope for vertical lifts. Sizes range from single-sheave units to large, multi-sheave assemblies designed for heavy-duty lifting. 

Key Components and Types

• Sheaves: Wheels the wire rope runs over; more sheaves mean greater capacity and better load stability.
• Hook & Swivel: The hook is usually mounted on a swivel for 360-degree rotation.
• Safety Latch: A mandatory component that ensures the load remains secure.
• Side Plates/Cheek Weights: Provide weight to keep the wire rope taut, especially when lowering empty (overhauling).
• Types: Single hook (general-purpose), double/ramshorn (heavy-duty, over 75 tons), and swivel/fixed.

Selection Considerations

• Load Capacity (SWL/WLL): The block must be rated for the maximum load and for the line parts.
• Wire Rope Size: Sheave grooves must match the crane's wire rope diameter.
• Weight & Headroom: The block's weight must be subtracted from the crane's overall lifting capacity, and its height affects max lifting height.
• Reeving: The ability to easily reeve (thread) the rope through sheaves is crucial, often handled by specialized construction blocks. 

Maintenance and Safety

• Inspection: Regularly check for swivel rotation, latch functionality, hook deformation, and sheave wear.
• Lubrication: Sheave bearings and hook thrust bearings require regular grease.
• Standards: Ensure compliance with ASME B30.20 or similar safety standards. 

Looking to buy Hook Blocks? Contact Exact Crane to search for new and used crane hooks and blocks for sale.