1. Each overflow valve in the hydraulic system can suppress abnormal high pressure in the circuit to avoid damage to the hydraulic oil pump and motor, and to avoid overload conditions.
2. Boom luffing safety equipment: When an accident occurs and the high-pressure hose or oil pipe in the boom luffing oil cylinder circuit bursts or is blocked, the balance valve in the hydraulic circuit becomes effective, locking the working oil from the lower chamber of the oil cylinder, preventing the boom from falling, and ensuring the safety of the work.
3. Boom elastic safety equipment: When an unexpected event occurs and the high-pressure hose or oil pipe in the boom elastic oil cylinder circuit bursts or is blocked, the balance valve in the hydraulic circuit becomes effective, locking the working oil from the lower chamber of the oil cylinder, allowing the crane to retract independently and ensuring safety during operation.
4. Height limit equipment: After the hook is lifted to a regular height, touch the limit weight, open the travel switch, and the "over winding" indicator light will light up. Together, block the operation of the hook lifting, boom extending, boom lowering, and other actions to ensure safety.
5. Leg determination equipment: When an accident occurs and the high-pressure hose or oil pipe leading to the straight cylinder of the leg ruptures or cuts open, the bidirectional hydraulic lock in the hydraulic system can seal the pressure oil in the two chambers of the leg sealing cylinder, so that the leg does not shrink or throw out, and then ensure the safety of the lifting work.
6. Lifting indicator: The lifting indicator is set on the side of the base arm, and can be clearly observed by the operator sitting in the operating room. It can accurately indicate the elevation angle of the lifting arm and the rated lifting capacity of the crane under corresponding working conditions.
7. Fluctuation limit device; For cranes with variable boom amplitude, minimum fluctuation limiters and equipment to prevent boom rebound and tilt should be installed.
8. It is necessary to install a trolley travel switch and terminal buffering equipment for the crane with variable amplitude of the trolley.
9. Extended information: Tower cranes are divided into two categories: upper rotating tower cranes and lower rotating tower cranes.
10. The bearing capacity of the former is higher than that of the latter, and in many construction sites, what we see is a tower crane with an upward rotating upward lifting and joint connection.
11. According to whether it can be moved, it can be divided into walking type and fixed type.
12. The fixed tower crane body is fixed and not rotating, and is installed on a whole concrete foundation, or on a strip or X-shaped concrete foundation. The walking type can be divided into four types: track type, car type, tire type, and track type.
13. In the construction of houses, fixed structures are generally used.
14. According to its amplitude variation method, it can be divided into two types: horizontal boom trolley amplitude variation and boom amplitude variation; According to its installation form, it can be divided into three types: self lifting, overall quick disassembly and assembly.
15. The most widely used are downward rotating, rapid disassembly, rail type tower cranes, and self elevating tower cranes that can be used for one machine with four purposes (rail type, fixed type, attached type, and internal climbing type).
16. The tower crane is the most commonly used lifting equipment on construction sites, also known as the "tower crane". It is lengthened (high) section by section (referred to as the "standard section") and used to lift construction materials such as steel bars, wooden beams, concrete, and steel pipes.
17. Tower crane is an essential equipment on the construction site.
18. The function of the tower crane tip is to bear the upper load transmitted by the boom pull rope and balance arm pull rope, and directly transmit it to the tower structure through the structural components of the rotating tower, turntable, support seat, etc. through the turntable.
19. The top of the self elevating tower is of truncated cone column type, forward leaning or backward leaning truncated cone column type, A-frame type and slant support type.
20. The boom form of tower cranes is divided into two types: horizontal and pressure rod.
21. When the boom is horizontal, the load truck runs along the horizontal boom to achieve a balanced luffing motion. The boom is longer, but the boom has a larger self weight.
22. When the boom is a press rod type, the luffing mechanism pulls the boom to pitch and change its amplitude, and the luffing motion is not as smooth as the horizontal type, but its self weight is smaller.
23. The lifting capacity of tower cranes varies with the amplitude.
24.The product of lifting capacity and amplitude is called the load torque, which is the main technical parameter of this type of crane.
25. Through the slewing mechanism and slewing support, the lifting height of tower cranes is large, and the inertia mass of slewing and walking is large.
26. Therefore, it is necessary to have good speed regulation performance, especially for the lifting mechanism, which requires light load fast, heavy load slow, and installation position micro movement.
27. In addition to using resistance speed regulation, eddy current brakes, frequency modulation, pole changing, thyristor, and electromechanical combination methods are also commonly used for speed regulation.
