Chocks, cradles and A-frames are typically made or timber or metal and as used to assist in restraining loads that are prone to rolling. They may be used to prevent rolling themselves, support other restraints to prevent rolling or prevent movement during loading. The development of load restraint systems using this type of equipment is closely linked to lesson 2.6 on complex loads, and are often used in engineered solutions.
Key Issues related to chocks, cradles and A-frames:
- Check to ensure they are of adequate size and strength (i.e. use timber or steel, rather than a compressible material, and height so that the item cannot ‘climb’ the sides if rolling.
- They should be placed underneath or at the base of the item to be restrained.
- There should be a snug fit between the chock cradle or frame.
- They should have good friction contact surfaces between the load , the chock, cradle or frame and the vehicle.
- They can either be attached to the vehicle or the load.
- Sand bags and sawdust bags should not be used as chocks during transport as the contents can deform or settle.
- Tie Down lashings should be as verticle as possible between the cradle contact point and the vehicle.
- Where direct lashings are used they should be placed opposite to the expected direction of movement which would result if the load was unrestrained.
Please see pages 160 to 162 of the LRG for more details of how to use chocks, cradles and A frames.
It is highly recommended that anyone considering using these types of solutions seek advice from a suitably qualified engineer.