Product name: KX1916 hand crane (crane)
Item no: KX1916 
Size: 270 * 70 * 230 mm
Weight: about 100g
Material: plastic accessories + belt pulley + screw + wire......
Color: red and yellow
Battery use: no
Packing: 200 PCS
Rules: 600 * 450 * 550 mm

 The ancient greeks classified pulleys as simple machines. The ancient greeks knew how to use compound pulleys as early as 400 BC. About 330 BC, Aristotle wrote the eighteenth question in his book the mechanical problem, which focused on the \"compound pulley\" system. Archimedes contributed a lot of knowledge about simple machines and explained the kinematics theory of pulley in detail. It is said that Archimedes alone used compound pulleys to pull a large ship full of cargo and passengers. In the first century AD, hero of alexandros analyzed and theorized about compound pulleys, proving that the ratio of load to force was equal to the number of rope segments bearing the load, known as the \"principle of pulleys.\"

Experimental objectives: 1. Preliminary understanding of mechanics and mechanical principles.
         2.
Know the application of crane in life.

         3. Knowing the structure of pulley can distinguish fixed pulley from movable pulley.

Scientific production:

1,Identify and prepare materials for the experiment.
2,Follow the instruction step to install.
3,The installation is completed for debugging.

Scientific principle:

Pulley block: pulley device composed of fixed pulley and movable pulley. It saves effort and can change the direction of force. But the pulley does not save work, because the pulley block saves force, but it costs distance. In order to save and change the direction of power, fixed pulley and movable pulley can be combined into pulley block.
Pulley block is matched by several fixed and moving pulleys, which can save effort and change the direction of force action. In use, the amount of effort saved and the winding method of the rope depend on the effect of the pulley block
Features: the pulley block hangs the object with several pieces of rope, and the force used to lift the object is a fraction of the total weight. The free end of the rope around the movable pulley is counted as one section, while the free end around the fixed pulley is not counted. Using block and tackle save the strength, but had a distance, the power distance is greater than the weight moving distance. What distance of the charges for the main crown block rao of the rope, the use of pulley block in the experiment, it's easy to see, although the use of pulley block saved but had a distance - dynamic moving distance is greater than the goods up.
 
Treasure of knowledge:

Pulleys are simple machines that lift heavy objects and save effort. A pulley is a small wheel with grooves around it that turns on its axis. A simple machine that rotates around a central axis is called a pulley. It consists of a circular disk with grooves that rotate around the central axis and flexible cables (rope, tape, wire, chain, etc.) that span the central axis.

Scientific development:

In mechanics, a typical pulley is a round wheel that rotates around a central axis. There are grooves on the circumferential surface of the round wheel, and the friction between the rope and the round wheel will drive the circle if you wind the rope around the grooves and pull either end of the rope   The pulley rotates about the center axis. A pulley is actually a deformed, rotating lever. The main function of pulley is to pull the load, change the direction of applying force, transmit power and so on. A machine composed of multiple pulleys is called a pulley block, or compound pulley. Pulley block has greater mechanical benefits and can pull heavier loads. Pulleys can also act as chain or belt-driven components, transferring power from one rotating shaft to another. The pulley can be divided into \"fixed pulley\" and \"movable pulley\" according to whether the central axis of the pulley moves. The center axis of fixed pulley is fixed, and the center axis of movable pulley can be moved. The fixed pulley and movable pulley can be assembled together to form a pulley block, pulley block not only save effort but also can change the direction of force.


In 10 BC, the Roman architect vitruvius described a lifting machine in his architectural manual. This machine has a mast with a pulley at the top of the mast. The mast is held in place by a stay, and the winch pulls the cable through the pulley to lift the weight. Some heavy machinery can use two masts, which form a herringbone, to move the hoist laterally, but only to a small extent, and the operation is very laborious.

The crane refers to the multi-action lifting machinery that lifts and carries heavy objects vertically and horizontally within a certain range. Also known as crane. Belongs to material handling machinery. The working characteristic of the crane is to do intermittent movement, that is, in a working cycle to take materials, migration, unloading and other actions of the corresponding mechanism is alternating work, crane in the market development and use more and more widely.