Snatch Blocks & Wire Rope Pulleys
Snatch blocks and wire rope pulleys are common lifting mechanisms used for rigging. Using a snatch block in a block and tackle application reduces the amount of force required to lift an abnormally heavy object. A pulley system is used in conjunction with wire rope or another type of rigging rope, by looping the rope through the pulley (around the sheave) several times before hooking to the object. The force required diminishes proportionately with the amount of pulleys or “loops” used during the hoist.
We supply a wide range of rigging blocks and pulleys including snatch blocks, derrick hoists, wire rope pulleys, from a range of quality manufacturers.
With so many different variations, sizes and weight limitations, it’s important to know what to look for when choosing a snatch block for the required application. Factors to keep in mind when choosing a snatch block include:
The Working Load Limit (WLL) of both the snatch block and the wire rope. If the WLL of the snatch block is not compatible with the WLL of the rope, it can create a dangerous situation if either one should fail.
The size of the sheave in the snatch block compared to the diameter of the wire rope. If the wire rope is too large for the sheave, the block can crack. Generally, the wire rope-to-sheave size ratio should be 12:1 in order to hold the wire securely whilst under load.
A snatch block can reduce the direct pull load by half, choose a snatch block that has a rating of double the pull of the winch you will be using.