Lifting block knowledge popularization

Lifting block is an important lifting tool. It has a simple structure and is easy to use. It can change the direction of the traction ropes of the block and tackle group and lift or move the moving objects several times, especially the block group composed of pulleys, with the hoisting machine. , Mast or other lifting appliances are widely used in construction and installation operations. Product specifications from 0.03-320T, the wheel train from the single wheel to the pickup wheel, hanging hook, link ring, hanging ring, hanging beam four, available for the user to choose. It is also a warrior of the same name in Transformers.

The main components are wooden frames, pulleys, short shafts, and ropes. The core components are pulleys. The pulley uses a rope to wrap around a groove in the middle of the pulley. A short shaft is worn in the pulley, and both ends are fixed on a wooden frame. This machine is called a pulley block. In 1988, the Ruichang ancient copper mine site was found in the middle of the Shang Dynasty. The pulleys were five-toothed, with a wheel width of 320 mm and a wheel diameter of 350 mm. It consists of a cymbal and two fixed pulleys, powered by cows. Obviously, it is more efficient than a single pulley. There is also a compound block which has two pulleys of different diameters on the same shaft. The large diameter is twisted. As the motive force, a winch is moved by a person to drive a small-diameter roach to rotate and hang the thing.

1. Simple lifting appliances that vertically lift heavy objects. It is small and compact. There are manual and electric two.

1 manual tackle. The traction chain is pulled by the manpower, and the weight is lifted by the worm and worm gear drive chain reel. The self-actuated brake with load, the greater the load, the greater the braking torque and the safe and reliable. The scope of work is a vertical line under the hook.

Nylon wheel aluminum lifting tackle:

Uses: Suitable for lifting towers, overhead lines, lifting equipment and live working.

Features: Light weight, good wear resistance of wheels, no damage to steel wire ropes and ropes. There are hook, ring, single door, double door.

2 electric block. The electric motor drives the gear train, wire rope drum and hook pulley to lift and lower the weight. The inside of the casing is a wire rope drum, which is connected with the motor and the gear transmission mechanism with the brake. The middle housing has lifting lugs. After hanging, vertical weights can be hoisted. The trolley can also be hung on the running trolley and becomes a running trolley, which runs along the overhead track and conveys the material inside the workshop or between the workshop and the workshop.

2. The number of pulleys is divided into single-door pulleys, double-door pulleys and multi-door pulleys. According to the connection between the trolley and the hanger, it can be divided into four types: hook-type pulley, chain-type pulley, ring-type pulley and hanger-type pulley. In general, small and medium sized tackles are mostly of the hook type, chain type, and ring type, while large sized tackles are of the ring type and hanging beam type. According to the different contact between the wheel and the shaft, it can be divided into two types: the axle-mounted sliding bearing and the rolling bearing. According to whether the splint can be opened to split, there is an open block and a closed block. The splint of the opening block can be opened, and it is easy to install ropes. Generally, it is a single door block, and it is often used as a guide block at the foot of a mast. Pulleys are divided into fixed blocks and moving blocks depending on the way they are used.

Easy to use, widely used, can be manual, mobile. It can change the direction of traction ropes of pulleys and skating trains and lifting and moving heavy objects, especially the pulley block composed of pulleys. It can be widely used in construction and installation operations in conjunction with winches, boring bars or other lifting appliances. . It is mainly used for the production and construction of factories, mines, agriculture, electric power, construction, installation of docks, docks, warehouses, lifting of goods, etc.

1 Manual tackle. The traction chain is pulled by the manpower, and the weight is lifted by the worm and worm gear drive chain reel. The self-actuated brake with load, the greater the load, the greater the braking torque and the safe and reliable. The scope of work is a vertical line under the hook.

2 Electric blocks. Motor-driven gear trains, wire rope drums and hook pulleys allow the weights to move up and down (see figure). The inside of the casing is a wire rope drum, which is connected with the motor and the gear transmission mechanism with the brake. The middle housing has lifting lugs. After hanging, vertical weights can be hoisted. The trolley can also be hung on the running trolley and becomes a running trolley, which runs along the overhead track and conveys the material inside the workshop or between the workshop and the workshop.

Block application:

The number of pulleys is divided into single-door pulleys, double-door pulleys and multi-door pulleys. It is mainly used for the production and construction of factories, mines, agriculture, electric power, construction, installation of docks, docks, warehouses, lifting of goods, etc.

There are many stocks of lifting chain rings, users should pay attention to their production quality when choosing. For example, there is a manufacturer's serial number on the lifting chain of each section, the tolerance of the inner width of the lifting chain ring is extremely small, and the surface of some chain links is coated with a fluorescent coating, which is marked with production in each specific length of the chain. Serial numbers and lot numbers, some of which have continuously recorded data produced and tested by the manufacturer within 10 years. Some fluorescent coating on the surface of the lifting chain can be pink at room temperature, and when the temperature reaches 225°C, the pink color gradually fades. At 250°C, the coating on the surface of the link becomes light yellow, brownish at 300°C, brown at 320°C, and black at 350°C, and black indicates that the user should not use the link.

At present, there are dynamic strength requirements for the lifting chain rings and their components (minimum number of fatigue cycles is 20,000), and the upper load limit for some components is 1.5 times the rated load. The user must always check the condition of the chain (wear and elongation) according to the operating conditions. Some manufacturers have used CrNiMo special alloy steel and other high-quality materials for lifting chain rings. In order to improve the toughness of the hoisting link ring, quenching and tempering treatment is performed to make it more resistant to scratches and hydrogen embrittlement. According to relevant standards, bending tests are also required. The ratio of rated load, test load and breaking load is 1:2.5:4.

In hoisting operations, the slings are used as a kind of slings that are easy to carry, are not easy to catch fire, are easy to maintain, and have little damage to hanging objects. They have been used in many applications. However, there are many types of slings. How should we choose when carrying out lifting operations?

According to the different classification methods, the industry has divided the lifting belt into many types. According to experts, the selection of lifting belt type should be based on the type of lifting equipment and the requirements of lifting operations.

In general, we will distinguish the types of lifting straps by length, short, round or flat. Choose the length or length of the lifting belt according to the height of the lifting operation and the way the hanging objects are tied, and select the round or flat lifting belt according to whether the surface of the hanging is worn or soft.

In addition, if it is a special operation occasion, we should also use the type of lifting belt that meets the corresponding characteristic requirements, such as acid, alkali, high strength, anti-corrosion and so on.

As for the different types of choices for lifting belts in terms of materials, in addition to lifting occasions with corresponding characteristics, the general lifting operations are not too different for polyester, polypropylene, and nylon.

As shown in the drawings, the heavy machine hook assembly is mainly composed of a pulley 1, a pulley shaft 2, a hook release device 3, a hook body 4, a cross beam 5, a bearing 6, a combination bolt 7, a round nut 8, a guide rope block 9 and Splint 10 and other components. In order to ensure the normal use of crane hooks, crane operators and maintenance personnel are required to carry out safety inspections of these components as appropriate, and include three items for inspection: one is to check technical documents, the other is to check the appearance and surface cracks, and the third is to measure wear. Quantity, opening degree, torsional deformation, etc.

I. Checking Technical Documents

Before the new crane is put into use, the operator shall check the relevant technical documents of the hook assembly. The rated load indicated on the label of the hook assembly shall be consistent with the actual lifting load. The relevant technical documents and factory certificate shall be complete.

Second, appearance inspection

The operator of the crane shall check the appearance of the hook assembly every day. The requirements for each component are as follows: The pulley 1 shall be flexible on the pulley shaft 2 with no obvious looseness; the rim of the pulley 1 shall be free from damage or cracks, otherwise it shall be replaced. The anti-unhook device 3 should be opened and closed freely, its spring should be intact to prevent the wire rope from slipping off the hook body 4; the hook body 4 should be flexible on the bearing 6 at the beam 5; the round nut 7 and the combination bolt 8 can not be loosened .

Third, check the hook surface crack

The hook body 4 is first cleaned with kerosene, and then the hook body is inspected for cracks with a 20x magnifying glass, and if necessary, a coloring method can be used for flaw detection. For the hooks of oversized tonnage cranes, non-destructive testing methods (magnetic flaw detection, ultrasonic flaw detection) should also be used to check for cracks inside and outside the hooks. If there is a crack on the surface and inside of the hook body 4, it should be replaced immediately.

Fourth, measuring the hook body geometry

1, the amount of wear

When carrying out a regular inspection of the crane, the amount of wear on the wear surface of the hook body 4 should be measured using a caliper or a caliper. If the force is greater than 10% of the original size should be replaced. When the crane is overhauled, the hook assembly shall be dismantled and the wear of the shafts of the pulley shaft 2, beam 5, bearing 6 and splint 10 shall be measured. When the wear reaches 5% of its original size, it should be replaced.

2, opening degree

The measurement method of the opening degree of the hook body 4 is as follows: carry out the load test according to the rated load stated on the hook tag, gradually increase the load to 1.25 times of the rated load in an incremental manner, and the lifting time is not less than 10 minutes. “After unloading, measure with a caliper. The degree of opening of the hook is compared with the size of the original opening, and the increase in the opening degree should not exceed 0.25%.

When a new hook is activated, a mark can be punched on each side of the opening of the hook body 4 and the distance between the two marks can be measured and recorded as the original opening size. "If the opening degree of the hook body 4 is more than the original opening degree An increase of 15% should be replaced.

3, reverse deformation

The method of measuring the torsional deformation of the hook body 4 is as follows: Observe the gap between the steel ruler and the side of the hook body 4 with the side of the steel ruler against the side of the hook body 4 . If the gaps on both sides of the hook body 4 are different, the hook body 4 is torsionally deformed. If it is necessary to accurately measure the torsional deformation of the hook body 4, it can be disassembled and placed on the platform to be checked with a ruler. The torsion deformation of the hook body 4 exceeds 10° and should be replaced.