Remember school knowledge about simple mechanisms? Block, lever … The essence of their work is obvious, and, despite their simplicity, they are extremely useful today, and we actively use them not only in everyday life, but also for industrial purposes.
Even at school, each of us goes through the concept of movable and fixed blocks, their purpose and reasons for using. Let me remind you that the axis of the stationary block is rigidly fixed (the stationary block in the picture is on the left), and the axis of the movable one, respectively, is movable. A movable block allows you to get a gain in strength, a fixed block changes the direction of the force applied to lift the load. Combinations of movable and fixed blocks can, depending on the design, give different possibilities. And they are called - pulley block.
Thus, a pulley block is a combination of movable and fixed blocks that go around a rope or chain, designed to gain a gain in strength or speed.
An example of the simplest chain hoist is a movable block (in the picture - in the middle). Using such a block, according to the laws of mechanics, we get a twofold gain in strength, that is, we can lift a load whose weight will be twice the force applied to the free end of the rope (though there will be a loss in distance, that is, the load will be lifted to a height half the length of the stretched rope). Accordingly, by complicating the design, using combinations of movable and fixed blocks, it is possible to obtain a gain in strength and a greater number of times.
It is difficult to list all the areas of use of the chain hoist, but it is worth mentioning lifting mechanisms, for example, such as lifting devices, cranes.
