Cranes and other lifting devices are needed to lift heavy materials for lifting and shifting them to their desired locations. For these operations, it is necessary to have devices that can secure the material to be lifted and allow it to be easily connected to the lifting mechanism.
The devices commonly used for this lifting and shifting are overhead lifting slings that have several lengths of strong material connected at one point and free at the other to be connected to the material that is to be lifted. These lengths of material will have hooks at one end that can hook on to the material being lifted at its lifting points and can be made from wire rope, synthetic materials, or chains.
A lifting sling must be chosen to give a balanced lift which can come from the number of attachment points, sling angles, and their length. The sling angles are best if they are closer to the vertical, but this can reduce the height to which materials can be lifted. The highest lifting point of the crane, and the length of the slings must be such that materials can be easily lifted to the desired height.
Chain slings are preferred to synthetic material slings as they are better at resisting impact and will not cause any cuts or abrasions, due to the rounded nature of the chains. They are also resistant to chemicals and will not be affected by UV radiation like synthetic slings will. This can cause these synthetic slings to snap and result in damage to materials and danger to people working around the lifting point. Chain slings can also be used in dirty or oily environments and at higher temperatures which will affect the lengths of synthetic slings.
Chain slings are preferred to wire rope slings, as they will never fray, as wire ropes will do after some usage. It is also easy to adjust the lengths of chain slings by shifting the attachment points that are spring-loaded and allow for this change. Chain slings will also never elongate when materials are lifted and have a much longer service life than synthetic or wire rope slings. Their inspection and maintenance are easy and the chain links can be repaired if they suffer damage in any way.
It is important to inspect slings before their use every day to make sure that they are in the right condition for lifting. All slings (whether they are new, altered, modified, or refurbished) should be inspected by a competent person before they are used in the workplace. This is critical if you want to make sure the sling is built to the required specifications, not damaged, and will be appropriate for the task at hand. For record-keeping purposes, it is useful if each chain has a metal tag with an ID number as well as load limit details. Furthermore, any information you can add about the chain length and other characteristics will be important and should be recorded in a log book.