Different kinds of Pulley Blocks made in china

Pulley blocks are also known as snatch blocks, these pulleys open so it’s easier to feed the rope through the housing—a free rope end is not needed. Use them to assist with horizontal pulling or to guide a rope.

Sheaves and pulley blocks are devices that aid the lifting or pulling of loads. They mount to a surface or suspend from equipment and have a grooved wheel (sheave) for guiding a wire rope or aircraft cable that's attached to the load. Pulley sheaves are replacement wheels for pulley block assemblies.

They work by distributing the weight of an object over multiple points of contact through the use of friction. A block and tackle is an assembly of pulley blocks and rope or cables that are set up to decrease the effort needed to haul or hoist heavy loads. Each block has one or more pulley. Thread the rope, alternating between the pulley attached to the block on the object you want to move and the pulley attached to a fixed block.

A snatch block or snatch pulley is an assembly using a wheel with a grooved edge for holding a rope or cable. They typically have side plates for attaching to a hook or shackle, with an axle or pin for turning the sheave. It is sometimes called an open block pulley

Pulleys are generally smaller and lighter-duty than blocks. Most are designed for use with soft rope, although some are designed with steel sheaves for use with wire rope. 

Used properly, It enhances the pulling power of your winch and changes the pulling direction without damage to the wire rope. Reeving blocks to set up a double pulley system requires a little thought. A double pulley system, also known as a "block and tackle," consists of the pulleys, or blocks, and the tackle, the ropes riven through the blocks.

Blocks can assist you in lowering by reducing the abrasion and friction on your bull rope thus making your ropes last longer. All blocks are rated by rope size and their average working load can be estimated by using is a 5:1 ratio. (Example: Block with 5,000 lb. rating would have a working load of 1,000 lbs., etc.)

Pulleys with two grooves are for use where multiple pulleys move a single load, such as block and tackle systems. They require about half the force of a single-groove pulley to move the same load. Warning: Never use to lift people or items over people.

Provided with double pawls and ratchet disc, this offered pulley block provides proper locking mechanism and extra safety.

They are widely used to lift heavy loads when only "manpower" is available and are sometimes used in conjunction with motorized lifting tackle. By using "fixed" and "movable" pulleys it is possible to gain a Mechanical Advantage. The capacity at which our products can be safely used has been established through an accredited testing laboratory. This may be defined as the safe working load limit, or cable rope pulley block load calculation, or a force calculator. The safe working load limit (mechanical advantage) is the maximum load in tons which should ever be applied, and when the load is applied uniformly and in direct tension to a straight segment of wire rope. By changing the degree of angle between lead and load angle, this also affects the stress on the block. The stress on the eye may be decreased by increasing the angle between the load and the lead angle.