Grab cranes are used in fields that cannot be completed by ordinary hook cranes. Most of them grab bulk materials. They are generally sold in a customized way. Unlike general cranes, grab cranes also need to determine the volume of the grab.
The more common crane grab forms in daily use are shell-shaped and multi-part. The shell-shaped grab grabs and loads and unloads bulk materials by the opening and closing of the left and right combined buckets. It is mainly used in sand making plants, coal mines, mines, and infrastructure construction to complete sand, coal, coal, and earthwork. Grabbing and lifting of bulk materials such as stones and soil. Timber and straw grabs are also a kind of shell-shaped grabs, which can be used to grab round logs in lumber mills, and straw processing plants to grab straw bales.
The multi-leaf grab is controlled by the opening and closing of multiple jaws to control the grabbing of materials. It is used for scrap steel grabbing and smelting work in steel mills, bulk waste, waste smelting, and loading and unloading at garbage disposal sites and construction sites. And handling work, the car recycling yard carries out the disintegration, refining and recycling of cars. The bucket teeth can be replaced, and the high-hardness wear-resistant steel is used to ensure a long service life; the flap shell can be selected according to different working environments; fully closed Valve shells, semi-closed valve shells, broad-sided valve shells and narrow-sided valve shells.
The working principle of the grab crane: at the beginning of the work, support the wire rope to lift the grab in the proper position, and then lower the opening and closing wire rope. At this time, the weight of the lower beam forces the large shaft of the beam below the bucket to open the bucket. When the bumps that open to the two ear plates collide, the bucket opens to the maximum limit. When the bucket is opened, the center distance between the upper beam pulley and the lower beam pulley is increased, and then the wire rope is supported to fall, and the opened grab is dropped on the loose accumulation to be grasped, and then the opening and closing wire rope is retracted to turn the upper beam pulley The center distance with the lower beam pulley is restored to the original position, thus completing the material grabbing process. The closed bucket is filled with materials, and finally the opening and closing wire rope is lifted, the entire grab is also hoisted, and moved to the required unloading site by a crane, and the grab is opened to unload the grabbed materials.
Grab cranes can be classified according to crane type, grab type, and driving mode.
According to the crane classification, it is divided into bridge grab crane, gantry grab crane, and knuckle boom grab crane. It can be divided into single beam grab crane and double beam grab crane.
Grab bucket overhead crane
The difference between grab bridge crane and ordinary hook bridge crane is that the former is to install the grab under the hook of the bridge crane, and control the opening and closing of the grab to complete the material grabbing work that the hook cannot complete.
The lifting equipment bridge grab crane is dedicated to bulk and granular materials.
The conventional configuration of the bridge grab crane: using the driver's cab control, the driver's cab is separated and closed. Each mechanism adopts winding type hoisting motor and resistance speed regulation.
Lifting equipment grab bridge crane working level: A6, A7, working environment 20℃~+40℃ This model is not recommended for working environment with explosion-proof and insulation requirements.
Other configurations for users to choose from the lifting equipment grab bridge crane:
1. There are two main beams, parallel and vertical, in the opening and closing directions of the grab;
2. Lifting weight includes grab weight;
3. When the trolley is equipped with a rain cover, the limit size of the top surface is H+h;
4. The total number of outdoor cranes and the maximum wheel pressure should be increased by 5% accordingly
5. There are two types of angle steel and safety sliding contact wire for cart conduction;
6. The crane has two options: standard trolley and weighing trolley;
7. Other types of grabs such as sugarcane grabs, garbage grabs, wood grabs, etc. can be equipped according to the needs;
8. Grabs are divided into: single rope grab, double rope grab, electric grab, and target set grab.
Grab gantry crane
Grab gantry cranes are mainly used in outdoor fixed cargo yards for transportation of mines, coal, wood, etc.
Knuckle boom grab crane
According to the loading and unloading objects, it is divided into log crane, sugarcane drop, etc. But with the development of science, has developed a multifunctional grab crane.
Single beam grab crane and double beam grab crane
Mainly refers to bridge cranes, which are divided into single-beam grab cranes and double-beam grab cranes according to the number of beams. The function is the same as the bridge grab crane.
According to the classification of grabs, it can be divided into shell grab cranes and multi-part grab cranes.
Shell type grab crane
It is suitable for loading various bulk cargoes, minerals, coal, sand and gravel, earth and stone, etc. in ports, docks, station yards, mines, etc. It can also be used for earth and stone excavation, foundation and trench excavation, road construction, railway track laying and other projects.
Multi part grab crane
It is suitable for scrap steel grabbing and sorting work in steel mills, bulk waste, waste sorting, loading and unloading and handling work in garbage disposal sites and construction sites, and automobile recycling yards for dismantling, sorting and recycling of cars. Bucket teeth can Replace, and use high-hardness wear-resistant steel to ensure long service life; valve shells can be selected according to different working environments; fully closed valve shells, semi-closed valve shells, wide-side valve shells and narrow-side valve shells. Timber grabs are mainly used for the grabbing and loading and unloading of logs, timbers, pipes, drums and other objects of various specifications. It can be grabbed by a single root or multiple roots. It can be used with cranes such as tower cranes and gantry cranes. It is suitable for occasions such as log storage yard and dock unloading. Straw bale grab is a kind of material handling equipment specially developed for straw power plants. It is mainly used for unloading, stacking storage and feeding of straw bales. The work level is high, and it is suitable for the needs of humid, dusty, frequent use and uninterrupted work in the working environment of the straw silo of the power plant.
According to the driving mode, it can be divided into two categories: hydraulic grab and mechanical grab.
Hydraulic grab crane
The hydraulic grab itself is equipped with an opening and closing structure, which is generally driven by a hydraulic cylinder. The hydraulic grab composed of multiple jaws is also called a hydraulic claw. Hydraulic grabs are widely used in special hydraulic equipment.
Mechanical grab crane
he mechanical grab itself is not equipped with an opening and closing structure. It is usually driven by a rope or external force of a connecting rod. According to the operating characteristics, it can be divided into a double-rope grab and a single-rope grab. The most commonly used is a double-rope grab.
The double-rope grab has a supporting rope and an opening and closing rope, which are respectively wound on the reel of the supporting mechanism and the opening and closing mechanism. The double-rope grab is reliable, easy to operate, high productivity, and widely used. After adopting two sets of double ropes, it becomes a four-rope grab, and the working process is the same as that of a double rope grab.
The single rope grab support rope and the opening and closing rope use the same steel wire rope. Through the special locking device, the steel wire rope alternately supports and opens and closes. The winding mechanism of the single rope grab is relatively simple, but the productivity is low, and it is rarely used in a large number of loading and unloading operations.
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