Extension of knowledge points:
The balance pulley is composed of pulley inner frame, pulley outer frame, pulley and shaft. Two pulleys are installed on both sides of the pulley inner frame with pulley shafts. The middle of the pulley inner frame is provided with an inner frame balance shaft hole, and the pulley inner frame is arranged in the pulley outer frame. The pulley outer frame is provided with a pulley outer frame balance shaft hole or an outer frame balance shaft groove corresponding to the pulley inner frame balance shaft hole. The balance shaft is installed between the inner frame balance shaft hole and the outer frame balance shaft hole or the outer frame balance shaft groove, and the pulley inner frame is wound on the pulley outer frame.
Question 2: What is the difference between the crown block, moving pulley, balance pulley, balance pulley and guide pulley of a crane? The function is different.
At the same time, there are differences in structure. According to the stress of the wheel, the structure and material of the wheel will be different
Generally, the structure of guide wheel is relatively simple, and its bearing capacity is slightly poor.
Other pulleys are basically the same.
Question 3: What is a pulley? Pulley, commonly known as gourd. The pulley is a small wheel with grooves around it, which can rotate around the shaft. A simple machine that can rotate around the central axis is called a pulley, which consists of a grooved disc that can rotate around the central axis and a flexible cable (rope, adhesive tape, steel cable, chain, etc.). ) across the disk.
Question 4: What is a crown block? What is a moving pulley? (1) crown block
The crown block is essentially an equal arm lever, which is labor-saving and effortless, but it can change the direction of force.
Characteristics of crown block
It is not labor-saving to pull the hook code through the crown block. Whether there is a crown block or not, the reading of the spring scale is the same. It can be seen that the direction of force can be changed easily by using the crown block. Many times, changing the direction of force will bring convenience to work.
Crown block principle
The crown block is essentially an equal arm lever, and the power L 1 and the resistance L2 arm are equal to the pulley radius. According to the lever balance condition, it can also be concluded that the crown block is not labor-saving.
(2) Move the pulley
The moving pulley is essentially a lever with a force arm twice as large as the resistance arm, which saves 1/2 force and spends 1 times more distance.
Characteristics of moving pulley
Using a moving pulley can save half the force and waste the distance. This is because when using the moving pulley, the hook code is hung by two ropes, and each rope only bears half the weight of the hook code. Although the use of moving pulley saves power, the distance of power moving is greater than the distance of hook code rising, that is, the distance is wasted.
Question 5: Are the crown block, balance pulley and balance pulley the same thing? The balance pulley and the balance slide rope are pulleys, but the crown block is not. It works in a different way. The crown block is used to support and change the direction of the wire rope, and the balance principle is used to balance the branch tension of the wire rope and adjust the length of the wire rope.
Question 6: What is a crown block and what is its concept?
When the pulley with fixed position penalty is used, the wheel rotates while the position of the whole pulley remains unchanged.
Principle and definition of crown block
The crown block is essentially an equal-arm lever, and both the power arm L 1 and the resistance arm L2 are equal to the pulley radius. According to the lever balance condition, it can also be concluded that the crown block does not save labor and distance. Like the pulley at the top of the flagpole, the pulley that rotates in a fixed position is called the crown block. Definition: When pulley is used, the position of shaft is fixed, which is called crown block. According to F 1*L 1=F2*L2, the essence of the crown block is an equal arm rod. Using the crown block can change the direction of force, but using the crown block cannot save labor and distance. The function of crown block is to change the direction of force.
Edit the purpose and requirements of this paragraph.
Understand the function of crown block. Can you save effort?
Edit the instruments and equipment in this paragraph.
Demonstration pulley block (J2 12 1 type), two dynamometers, hook code, rope and bracket. Its function is to change the direction of force, unlike moving pulley, which only changes the magnitude of force without changing the direction of force.
Edit this experimental method
1. Take a pulley and fix it on the square bracket to form a crown block. Use a thin rope to pass through the pulley, use the hook code at one end of the thin rope as resistance, and hang a dynamometer at the other end of the wire rope (Figure 1.47- 1). 2. Pull the dynamometer vertically downward at a uniform speed by hand, and observe the reading of the dynamometer when the pulley is balanced. 3. Change the direction of dynamometer tension (horizontal, downward, downward). When the pulley is balanced, record the reading of each dynamometer. 4. Change the weight of the hook code, repeat the above experiment and record the reading of each dynamometer. 5. The experimental data show that the reading of dynamometer is equal to the weight of hook code within the allowable range of experimental error. It is concluded that using the crown block is neither labor-saving nor laborious, but it can change the direction of force.
Open classification:
Instrument, physics, moving pulley
Question 7: How to better master the balance of roller skating? The most important thing is the center of gravity. Center of gravity should be low. In order to keep the center of gravity, you should slide with your legs and feet instead of your body. Bend over and bend your legs to lower your center of gravity, and climb right with your right foot. Remember that your feet are inclined, not straight, so you can't climb up. Put your feet straight when you close your legs, and so does your left leg. Remember that keeping the center of gravity balanced is the key, and try to lower the center of gravity as much as possible. If not, please ask me. My QQ number is1172069013.
Question 8: What are pulley blocks and pulleys? The pulley block is composed of several crown blocks and moving pulleys, which can save labor and change the direction of force. In use, how much labor is saved and how the rope is wound depends on the use effect of the pulley block. The moving pulley is borne by two ropes, that is, the force borne by each rope is a fraction of the total weight of the object and the moving pulley. Number, the principle is: when n is odd, the rope is driven by pulley. When using a moving pulley, you have to bear three sections of rope, and then you add two sections of rope for each additional moving pulley. If n=5, two movable pulleys (3+2) are needed. When n is an even number, the wire rope starts from the crown block. At this time, all the moving pulleys are only borne by two ropes. If n=4, two movable pulleys (2+2) are needed. Secondly, the number of crown blocks is determined according to the needs. The principle is: generally, two ropes are equipped with a moving pulley, and generally, a moving pulley is equipped with a crown block. When there is no need to change the direction of force, even-numbered ropes can reduce one crown block; To change the direction of force, you need to add a crown block. To sum up, the design principles of pulley blocks can be summarized as follows: (1) odd motion and even determination; Move a certain number, even number MINUS a certain number, change direction plus a certain number. A simple machine that can rotate around the central axis consists of a grooved disc that can rotate around the central axis and a flexible cable (rope, adhesive tape, steel cable, chain, etc.). ) across the disk. Pulley is the deformation of lever, which belongs to lever simple machinery. In China, as early as the Warring States Period, there was a record about pulleys in the book Mo Jing. The pulley with the fixed central shaft is called the crown block, which is a deformed equal arm lever, and can change the direction of force without any effort. The pulley whose central axis moves with the weight is called the movable pulley, which is a deformed unequal arm lever, and can save half the force without changing the direction of the force. In practice, a certain number of moving pulleys and crown block are often combined into various pulley blocks. The pulley block can save labor and change the direction of force. The differential pulley (commonly known as chain block) commonly used in factories is also a kind of pulley block. Pulley blocks are widely used in cranes, winches, elevators and other machinery. There are two kinds of pulleys: crown block and moving pulley, which are combined to form a pulley block. (1) The crown block is essentially an equal arm lever, which is labor-saving and effortless, but it can change the direction of force. The characteristic of the crown block is that it is not labor-saving to pull the hook code through the crown block. Whether there is a crown block or not, the reading of the spring scale is the same. It can be seen that the direction of force can be changed easily by using the crown block. Many times, changing the direction of force will bring convenience to work. Principle of crown block The crown block is essentially an equal-arm lever, with power L 1 and resistance L2 arm equal to the pulley radius. According to the lever balance condition, it can also be concluded that the crown block is not labor-saving. (2) Moving pulley The moving pulley is essentially a lever whose power arm is twice as large as the resistance arm, which saves the force of 1/2 and takes the distance of 1 times more. The characteristics of moving pulley The use of moving pulley can save half the power and spend more distance. This is because when using the moving pulley, the hook code is hung by two ropes, and each rope only bears half the weight of the hook code. Although the use of moving pulley saves power, the distance of power moving is greater than the distance of hook code rising, that is, the distance is wasted. The principle of moving pulley is essentially a lever, and its power arm (L 1) is twice as big as the resistance arm (L2). (3) Pulley block: Pulley block consisting of crown block and moving pulley can save energy and change the direction of force. The pulley block uses several lengths of rope to lift the object, and the force used to lift the object is a small part of the total weight. The free end of the rope bypasses the movable pulley, but it does not count. Although the pulley block is labor-saving, it takes a long distance, and the distance of power movement is greater than that of heavy objects. Pulley. When using the pulley block, the labor is saved. The pulley block hangs the object with several ropes, and the force used to lift the object is a fraction of the weight of the object. The characteristics of pulley block are used in experiments. It is easy to see that although the pulley block is used, it saves energy, but it takes distance-the distance of power moving is greater than the distance of goods rising.
Hope to adopt
Question 9: What is the balance condition of the pulley block? Is it the same as a lever? Five-point reciprocity, when the balance of two forces (static) moves, is when the balance of two forces is broken.