Slings - what they are and their types
What is a sling?
A sling is a component of the lifting equipment of a crane, gantry or hoist on which the load to be lifted is suspended, supported or lashed. The sling makes it possible to move both delicate loads and large, heavy ones. A large number of different types of components and materials are required to construct such slings. We can classify slings from various angles. There are two main types: General Purpose - Draw-wire sling
They are manufactured from equal materials. Due to the type of work to be carried out, we have different types of tendon sling:
They are used for both vehicle pulling (as winches on trucks or off-road vehicles) and heavy lifting. They are a standard accessory in industry and the construction industry. Rope slings are made of stranded steel and galvanised wires. The ropes are braided around a fibre core. They can be classified according to the type of clamp, the number of strands or the type of termination. As far as the number of strands is concerned, there are four types of these slings: one-, two-, three-, four-strand and one-, two-loop.
They are made of steel chains and are the strongest of all slings. This is why this type of sling is used in jobs that require the transport of very heavy loads (often in industry and construction). They can handle weights from 1 to 100 tonnes. They are used in what is known as material handling. Chain slings are resistant to changing weather conditions and mechanical damage. A distinction is made between one-, two-, three- and four-legged slings, single- and double-loop slings as well as hook and link and closed-circuit slings.
Natural and synthetic fibre webbing slings
Belt slings are light, soft and flexible. They allow a better distribution of forces when the load is pressure-sensitive. They are used to transport materials with sensitive surfaces.
Special purpose - gripping and hooking
When the use of general-purpose slings is not sufficient, special-purpose slings are used. These are made using a different technology, e.g. special-purpose slings for the transport and handling of technical gas storage cylinders.
Slings can be used in many different ways. They are often found in heavy industry: metallurgy, factories or metallurgy, but we also find them in the automotive, armament or construction industries.
Maintenance and inspection of slings
In order to work safely with slings, regular checks and inspections are necessary. Before using a piece of equipment for the first time, an initial inspection should always take place. This is to check that it can be used for work. Thereafter, the condition of the slings should be checked before each subsequent use. In addition to the daily inspection of slings, it is compulsory to carry out technical tests on them (for example, once a year for rope, belt and chain slings and every 6 months for shackles). Proof that the testing has been carried out and that the slings have been approved for use is provided by a protocol. Sometimes there is a requirement to mark the test carried out directly on the sling (in the form of a tag or plate).