The hook is the part of the crane that actually carries the load, so choosing it correctly is a safety matter. This guide explains the main hook types, how the lifting capacity is chosen and what to inspect in service.
Forged hooks and their types
Crane hooks are forged from steel, in a drop-forged or hammer-forged process, and fitted with or without a safety latch. The two common shapes are:
- Single hooks. One curved horn, used for most lifting work. They are covered by DIN 15401.
- Ramshorn (double) hooks. Two horns, used for heavier loads and slings that must be balanced. They are covered by DIN 15402.
Hook materials, mechanical properties, lifting capacities and stresses are covered by DIN 15400.
How the hook size is chosen
Hooks are numbered. The number is chosen from a table using three things:
- The lifting capacity the hook must carry.
- The strength class of the hook material.
- The duty group of the mechanism under FEM or ISO.
A higher hook number carries a higher capacity. The same hook number carries less load in a heavier duty group, so a crane that works continuously needs a larger hook than one used occasionally for the same load.
Count everything on the hook
The rated load includes more than the product. The hook block, lifting beam, sling or magnet all add to what the crane carries. Always add them when you work out the rated capacity.
The safety latch
A safety latch closes the opening of the hook so that a sling cannot slip off, for example when the load is set down and the sling goes slack. Where the load could slip off, a latch or an equivalent device is generally required. Check the rule in the standard named in your specification.
Hook block and rope
- The hook block holds the hook, the sheaves and the bearing, and it lets the hook turn.
- The number of rope falls and the sheave size are set with the hoist, not chosen separately.
- CESAN hoists are supplied with a hook block matched to the rated load.
Inspection in service
- Look for cracks, deformation, corrosion and wear in the throat and the bearing surface.
- Measure the throat opening and compare it with the original value.
- Check that the safety latch closes properly and the hook turns freely.
- Remove the hook from service and replace it if it is damaged, worn beyond the manufacturer’s limits or has been overloaded.
- Never repair a hook by welding or bending.
What to tell your supplier
- Rated capacity and the weight of lifting accessories.
- Duty group or the number of lifts per hour and hours per day.
- Whether you need a single hook, a ramshorn hook or a special attachment.
- The standard your specification requires.
Send us your requirements
To specify the right hook and hook block, send the rated load, accessories, duty class and the standard your project follows. Send them through the enquiry form and our engineers will reply with a technical and budgetary assessment.
See our electric hoists, overhead cranes and the guide to CE, FEM and DIN.