1. Pulleys and tackle blocks
Pulleys and pulley blocks are commonly used lifting tools in lifting and handling operations.
The pulley is composed of hook chain, pulley, shaft, shaft sleeve and splint. According to the number of wheels, it is divided into single-door, double-door and multi-door pulleys. According to the connection mode between pulley and suspended object, it can be divided into four types: hook type, link type, lifting ring type and hanging beam type. Generally, small and medium-sized pulleys mostly belong to hook type, link type and lifting ring type, while large pulleys adopt lifting ring type and hanging beam type. According to the different contact between wheel and shaft, it can be divided into sliding bearing and rolling bearing installed between wheel and shaft. According to whether the splint can be opened, there are open pulleys and closed pulleys. The splint of the open pulley can be opened to facilitate rope loading. Generally, it is a single-door pulley, which is often used as a guide pulley at the foot of the boom. Pulleys can be divided into crown block and moving pulleys according to different ways of use.
The pulley block consists of a certain number of crown block, moving pulleys and ropes. When lifting heavy objects, we should not only change the direction of force, but also save energy, so that neither crown block nor the pulley can solve the problem. If the crown block and the moving pulley are connected to form a pulley block, it can not only save labor, but also change the direction of force.
If the multi-door crown block and the movable pulley are connected together to form a multi-door pulley block, the heavy objects can be lifted with less force. As long as the 0.5- 15t winch is used to pull the output end of the pulley block, several tons or hundreds of tons of objects can be lifted. Therefore, the pulley block is a widely used lifting tool in lifting operation.
2. Jack
Jack, also called weight lifter, is widely used in lifting work. It can lift heavy machinery and equipment with little force, and can also correct the deviation of equipment installation and the deformation of components. The lifting height of the jack is generally 100-400 mm, and the maximum lifting weight can reach 500t.
Jack is divided into rack type, screw type and hydraulic type according to its structure and working principle. Jack should be flat when using, and the top and bottom should be padded with wooden boards; Don't overload the jack, and the height of the jack should not exceed the marking line on the piston;
When jacking, the sleeper should be placed under the object to prevent the piston from falling suddenly due to the tilt of the jack or oil return; When several jacks are used together, a synchronous lifting device should be set.
Step 3: snap ring
The snap ring, also known as armor removal, is used to connect the rope buckle (1000 kg rope and wire rope) with the rope buckle, or the rope buckle with the component lifting ring. It is a connecting tool widely used in lifting operation. The snap ring consists of a bent ring and a pin, which are divided into straight and horseshoe shapes according to the form of the bent ring; According to the connection form of pin and bending ring, there are pin-type and pin-pulling clasp and semi-automatic clasp.
The snap ring must be forged; When in use, it shall not exceed the specified load; Pin-pulling snap rings are often used to lift columns. After the column is fixed in place, the pin can be pulled out on the ground with the palm rope tied to the pin tail in advance, and the sling can be untied, thus avoiding the aerial work when releasing the buckle, reducing the unsafe factors and improving the hoisting efficiency. However, when the weight of the column is heavy, in order to improve the safety, the bolt-type clasp must be used.
Step 4: Rope clamp
The rope clamp of the steel wire rope is mainly used for temporary connection of the steel wire rope, fixing the rope on the back of the hand when the steel wire rope bypasses the pulley block, and fixing the rope head of the cable wind rope on the boom.
It is a wire rope clamp widely used in lifting operation. There are three kinds of commonly used wire rope clamps: horse-riding type, fist-clenched type and pressure plate type. Among them, the riding clip is the standard wire rope clip with the strongest connection force and is the most widely used.
Step 5 hook
Hooks can be divided into single hook and double hook according to different shapes. Single hook is generally used for small and medium-sized cranes, and it is also one of the commonly used lifting tools. In use, the single hook is simpler than the double hook, and the stress condition is not as good as the double hook, so the crane with large lifting capacity often uses the double hook. Double hooks are mostly used on gantry cranes.
Hooks are divided into forged hooks and plate hooks according to forging methods. Forging hook is made of 20 # high quality carbon steel. After forging and stamping, it is annealed to eliminate residual internal stress and increase its toughness. Before processing, the hardness should reach HB = 75 ~ 135. The plate hook is riveted by 30mm thick steel plate, with single hook and double hook, and is often used on heavy cranes.
6. Lifting of components
Special construction scheme should be prepared for component hoisting, which is also an integral part of construction organization design. In the construction scheme, the hoisting method and equipment should be selected according to the weight, use, shape, construction conditions and environment of hoisting components; Composition of lifting personnel; Hoisting sequence; Ways of component correction and temporary fixation; Protection of suspended operation, etc.
Move the gourd by hand
Manual hoist is a portable and simple manual traction machine. It has the characteristics of compact structure, small volume, light weight, convenient carrying and stable performance.
Its working principle is that two pairs of smooth self-locking pliers alternately clamp the steel wire rope to do linear reciprocating motion like two steel claws, so as to realize traction. It can be used for traction, hoisting, lifting and other operations of various projects.
When using chain block, the lifting capacity shall not exceed the allowable load, and it shall be used according to the indicated lifting capacity; Don't lengthen the handle at will, use steel wire rope to operate.
8. grinding
Grinding machine is a widely used human traction tool, which is mainly used in remote areas and construction operations with low lifting speed, no electric hoist, no power supply and small traction.
The grinder consists of a grinding core, a connecting rod, a grinding rod and a grinding rack supporting the grinding core and the connecting rod wound with steel wire rope. The use site of the pulverizer should be flat and spacious, and the wringer has enough rotation space. The first guide wheel in front of the grinder should be basically on the same horizontal plane as the grinding center of the grinder; The number of turns of the wire rope wound on the grinding core shall not be less than 3; The grinder shall be firmly connected with the ground anchor, and the grinding wheel frame shall not be tilted or suspended.
9. Chain inversion
Inverted chain, also called inverted chain block or gourd, can be used to lift light components and tighten the cable wind rope of the boom. When handling components or equipment, it can tighten the tied rope. It is suitable for short-distance hoisting of small equipment and heavy objects. Generally, the lifting weight is 0.5 ~ 1t, with a maximum of 2t.
Before using the chain, check to ensure that all components are sensitive and undamaged; When lifting, the lifting capacity should not be exceeded. When used in any direction, the zipper direction should be consistent with the sprocket direction. Attention should be paid to prevent the hand-pulled zipper from coming out of the groove, and the strength of the zipper should be uniform, not too fast or too hard; The number of zippers depends on the lifting capacity of the chain. If you can't pull, find out the reason and pull again; When the lifting of heavy objects stops in the middle, the small chain should be bolted to the big chain of the lifting sprocket to prevent the self-locking failure from taking too long.