L68A1 Mast Section Detailed explanation of single beam crane, single beam crane structure
The electric single beam crane mainly includes three operating mechanisms: lifting operation mechanism, crane operation mechanism and trolley operation mechanism. The hoisting operation mechanism is mainly composed of electric hoist, steel wire rope, pulley, hook or sling. The metal structure of the electric single beam bridge crane is mainly composed of the main beam and the end beam. The main beam structure is mostly the composite section of I-beam and steel plate, which is composed of the cover plate, web plate and I-beam steel. There are longitudinal and horizontal stiffener plates in the box. Its safety and reliability directly affect the operation quality and working ability of the crane.
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II. Fabrication features of steel structure
1. The main steel structure (main beam and end beam) materials are Q235-B, and the materials used are provided with material report and corresponding qualification certificate.
2. The manufacturing, welding and inspection of steel structure shall be carried out in accordance with national standards. Double groove welding process shall be adopted for important stress butt welds, and visual inspection and NDT shall be conducted as required. All welders shall hold corresponding grade certificates.
3. All the main beams of the crane adopt the technology of no butt joint of the whole plate, cancel the butt weld of the steel plate of the main beam, and eliminate the hidden danger of the butt weld quantity of the steel plate. (butt welding of steel plate is the most important welding and the part with the most potential quality hazards)
All the plates are cut automatically by numerical control cutting machine, and the camber of main beam is preset to avoid the problem of camber deflection of main beam by traditional fire drying.
5 the steel surface shall be shot blasted, and its surface roughness shall be grade Sa2.5 in gb8923 steel surface treatment registration and derusting grade before coating, so as to improve the paint adhesion, not to peel off the paint, and ensure the long-term beauty of the whole single beam crane
6. The longitudinal waist weld of the main beam adopts the domestic advanced automatic special machine for ambush welding, which is beautiful in shape and ensures the welding quality.
7. The crossbeam of the crane is made of rectangular tube as a whole, with no splicing and welding seam, beautiful appearance, strong and durable.
8. All the wheels are installed by boring to avoid that the wheel tread is not on the same level and improve the running accuracy of the wheel.
III. performance characteristics of mechanical system
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The hoisting mechanism of single beam crane is composed of Kaicheng double speed electric hoist, a Sino foreign joint venture brand. The product has the advantages of compact structure, light weight, small volume and convenient operation.
a. Reducer: the electric hoist reducer of single beam crane adopts three-stage reduction of helical gear. The gear and gear shaft are forged with 40Cr or 20CrMnTi steel, and are all supported by rolling bearing after heat treatment. The case is made of cast iron, with tight assembly and reliable dust prevention.
b. Drum device: the drum is made of cast iron or seamless steel pipe, connected with the reducer by splines, and the other end is supported on the front end of the tapered motor by rolling bearings. The drum shell is made of steel plate.
c. Hook device: the hook is made of 20 steel die forging, and is connected with the shell through the hook beam with the thrust ball bearing, so that the hook can operate freely.
d. Coupling: the torque of the motor is transmitted to the reducer through the claw type elastic coupling, which can absorb the load impact to obtain a stable start.
e. Slow drive device: the slow drive device consists of a drive box, a box cover and a small motor. The small motor drives the main motor through the slow device.
f. Limiter: in order to prevent the failure caused by the hook rising and falling beyond the limit position, the hoist is equipped with a limiter. When the hook reaches the limit position, the rope guide on the drum device of the single beam crane drives the limiter to act, so as to automatically cut off the power supply and stop the hoist.
g. Motor: the lifting motor adopts the cone brake motor with larger starting torque to adapt to the frequent direct starting in the intermittent work of the product. The maximum torque is 2.4-3 times of the rated torque.
h. In order to ensure the safety and reliability of use, all electric hoists are equipped with lifting limiters.
i. Electric control system: it is mainly composed of control box and operation button box of single beam crane, with protection or warning functions such as voltage loss, interlock, overload, overload alarm, etc.
2 trolley running mechanism
The operation mechanism of electric hoist of single beam crane is electric trolley type. The reduction gear is forged with 40Cr, and after quenching and tempering treatment, it is installed in the closed reduction box, all of which are supported by rolling bearings. The wall plate is made of steel plate, which ensures flexible operation, convenient use and long service life. The trolley running mechanism is equipped with frequency converter, stepless speed regulation, stable operation, accurate positioning and comfortable operation.
3 crane operation mechanism
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The gantry running structure of single beam crane is composed of motor, reducer and wheel group. The wheels are 45 × forgings. The hardness after heat treatment is HB ≥ 330-390 on the tread and Hb ≥ 260 at the depth of 20mm. The material of shaft and gear is 45 × or 40Cr after tempering. The crane drive is a new LDA type drive device, which has the advantages of simple structure, small volume, large starting torque, frequent starting, stable running speed, low noise, safe and reliable use, convenient installation and maintenance, beautiful and generous, etc.
Single beam crane crane crane crane crane crane is equipped with frequency converter, stepless speed regulation, stable operation, accurate positioning and comfortable operation.
