What are the port lifting equipment?

Abstract: Port crane is a kind of lifting machinery and equipment specially used for cargo loading and unloading and container hoisting in port. Because it has the advantages of stable transmission, high working efficiency, simple operation and low failure rate, it has been widely used in port operations and has become one of the important conditions to measure the advanced degree of ports. The classification of port cranes can be divided into three categories: portal cranes, fixed cranes and marine cranes. Q&A on Port Hoisting Machinery What are the port hoisting equipment?

Port lifting machinery

1. Which three load combinations should be used for load calculation of cranes?

(1) Case 1, windless normal working condition, mainly calculating the heating of the motor, the wear and pitting of wheels, tracks, idlers, gears and other parts, and the fatigue of transmission parts and supporting parts of the mechanism.

(2) Working condition 2: It is windy in normal working condition, which mainly calculates the power of the motor; Static strength, static stiffness and instability of transmission parts and supporting parts; Check the overload capacity of the motor; Calculate the input power of the reducer and select the reducer; Determining the braking torque of the brake; Check the overturning stability of the whole machine and local cranes under working conditions.

(3) Working condition 3, special load working condition, is mainly used to check the anti-overturning stability and anti-wind and anti-skid safety of the crane in non-working state; Check the transmission parts, support parts, anti-overturning devices and wind-proof and anti-skid devices of the mechanism bearing wind load; Select and check various safety devices, etc.

2. Please describe the working principle of the double rope grab?

(1) empty catch drops. After unloading, the grab bucket is in the open state, the support rope and the closed rope descend synchronously, and the grab bucket remains in the open state and falls on the cargo pile.

(2) catch the goods. After lowering the empty grab into the cargo pile, continue to loosen the support rope and the closed rope, so that the grab can be inserted into the cargo pile under its own weight. Then, the closed rope is put away, and the grab bucket is gradually closed to grab the goods.

(3) Full grab bucket rises. After the grab is closed, the support rope and the closed rope rise synchronously, and the cargo grab rises. At the beginning of this process, all the weight of the cargo grab is borne by the closed rope, and then the load is shared equally by the support rope and the closed rope.

(4) Unloading. After the cargo grab is transported to the unloading place, loosen the closed rope, and the grab will automatically open and unload the cargo under the action of the lower bearing beam, jaw plate and the weight of the cargo. In this process, all the weight of the cargo grab is borne by the support rope.

3. What is the significance of realizing the horizontal displacement of load during amplitude variation? What is the principle of pulley block compensation method?

(1), the center of gravity of the object moves along the trajectory of horizontal line or approximate horizontal line, and the height of the center of gravity of the boom system remains unchanged or changes little. This reduces the driving power of the pitch mechanism.

(2) Working principle: In the winding system of lifting wire rope, a compensation pulley block is added to compensate the lifting of articles in the luffing process. If at all positions in the luffing process, the upward value (downward value) of the article caused by the lifting (or lowering) of the boom is exactly equal to the downward value (upward value) of the article caused by the shortening (or increasing) of the length of the compensation pulley block, then the article will move along the horizontal line, thus meeting the requirements of the horizontal luffing of the article.

4. What measures does the track operation mechanism take to avoid wheel slipping?

(1) Adjust the motor power (or adjust the starting performance) and adjust the braking torque of the brake.

(2) Increase the number of driving wheels and use all wheels as driving wheels when necessary.

(3) Adjust the arrangement position of each component and change the wheel pressure distribution of the driving wheel.

(4) Reduce the average acceleration and deceleration and prolong the starting and braking time.

(5) Add sanding device to increase the adhesion coefficient between wheel and rail.

5. At the lowest lifting height, why must the steel wire rope wound on the lifting drum have 2 ~ 3 safety rings?

(1) The fixing device at the end of the wire rope on the drum shall have locking or self-tightening performance. The fixing of the wire rope end should be checked once a month. In any state of use, it is necessary to ensure that the wire rope has enough safety rings on the drum.

(2) The drum end of the multi-layer drum should have a flange, which should be 2 times the width of the wire rope diameter higher than the outermost wire rope.

(3) When the wire rope is wound on the drum, it should be closely and orderly arranged, and there can be no job-hopping and disorderly winding.

6. How to ensure the verticality of the center of the slewing column in the slewing bearing device?

(1) Upper support: Generally, horizontal rollers are installed on the rotating upright posts, and annular rails are installed on the inner side of the support ring above the gantry. Bear horizontal force.

(2) Lower support: Due to the vertical force and horizontal force, self-aligning roller bearing with centripetal thrust or combined bearing can be adopted, that is, it consists of a thrust bearing and a radial bearing (both bearings should have the same self-aligning).

(3) Adjustment: In order to adjust the clearance caused by installation error and rail and roller wear, the rolling bearing of the horizontal roller is usually sleeved on the eccentric shaft sleeve. The shaft sleeve is connected with the main shaft of the roller through a key, and the clearance between the roller and the raceway can be adjusted by rotating the main shaft.

7. The failure form of wire rope and the measures to improve its service life?

(1) In the working process, the steel wire rope is not only under tensile stress. In addition, due to winding on pulleys or drums, contact stress and bending stress are generated, which are fluctuating and lead to metal fatigue.

(2) There are the following methods:

A, try to reduce the bending times of wire rope, especially try to avoid the reverse bending of wire rope.

B, increase the diameter of pulley drum, the minimum diameter of pulley drum should meet the service life requirements of wire rope.

C, choose the appropriate steel wire strength, 1570- 1960N/mm2 steel wire rope life is longer.

D, select the appropriate pulley material and surface hardness to match the hardness of the wire rope and pulley.

E, strengthen the maintenance of wire rope, regular lubrication, can reduce the wear and tear of wire rope.

8, lifting operations, how to choose the transmission ratio of pulley block?

(1) small magnification and small lifting weight;

(2) The magnification of lifting weight is large;

(3) The magnification of double pulley block is small;

(4) The main control of lifting height adopts small magnification.

9. What are the main requirements of the track operation mechanism for the track?

(1) The top surface of the track should be able to withstand the extrusion of wheels;

(2) The bottom surface should be wide enough to reduce the compressive stress on the foundation;

(3) The section should have good bending strength.

10. Why do you choose a normally open brake for the slewing mechanism?

(1) When the party load and the load caused by the inertia movement of the rotary part change sharply, the rotary mechanism can still brake smoothly.

(2) When encountering strong wind, the rotating part can automatically return to the downwind position, thus reducing the overturning risk.

1 1. What is the function and working principle of the limit torque limiter in the rotating mechanism? How to adjust?

(1) function: prevent the rotary drive from being overloaded occasionally, and protect the motor, metal structure and transmission parts from being damaged.

(2) Principle: During normal operation, the torque of the worm is transmitted to the pinion shaft through the friction torque between the conical friction disk of the turbine and the upper conical friction disk, which drives the pinion to rotate; When the torque to be transmitted exceeds the torque that the limit torque coupling can bear, the upper and lower conical friction plates begin to slip, thus limiting the torque to be transmitted and playing the role of safety protection.

(3) Adjustment: There are usually two kinds of limit torque limiting devices:

1, the cooperation between spring and boss structure is a kind of torque limiting mechanism that can be repeated. This can adjust the spring pressure to change the torque limit.

2. The safety pin structure is adopted as a preventive device to prevent the damage of important institutions, which belongs to the irreversible ultimate protection. Reuse requires additional pin configuration.

12. How to ensure that the rack graduation line is always tangent to the gear graduation circle during amplitude variation?

(1) The upper pressure roller, the lower idler and the pinion are all installed on the cradle, which can swing around the axis of the cradle during amplitude change to ensure good meshing between the gear and the rack;

(2) Both the upper pressure wheel and the lower pressure wheel are installed on the eccentric shaft, which is convenient for adjusting the meshing clearance between the pinion and the rack, so that the pinion and the rack have good meshing;

(3) Self-aligning bearings are installed at the hinge shaft and tooth wall of the rack, so that the rack and pinion can mesh normally in the luffing process.

13, wire rope scrapping conditions

(1) The number of broken wires reaches the specified value;

(2) The whole wire rope is broken;

(3) The wear of the outer steel wire reaches 40% of its diameter;

(4) There is obvious corrosion inside and outside the wire rope;

(5) The wire rope is severely deformed.

14. Briefly describe the characteristics of variable amplitude drive driven by rack.

Rack transmission efficiency is high, structure is compact, installation is convenient, and it can bear bidirectional load. However, its working conditions are poor and easy to wear; There is impact when starting and braking, which makes the operation unstable, so a buffer is installed at the end of the frame connected with the boom.

15. Try to analyze the influence of the self-weight of the grab and the opening and closing pulley block on the grabbing ability of the grab.

The self-weight of grab is the source of grasping force. To improve the grab performance, it is required that the self-weight of the grab should be distributed reasonably in all parts, and increasing the weight distribution ratio between the upper bearing beam and the pillar is most beneficial to improve the grab performance.

16. How to adjust the installation gap between the horizontal roller and the track in the slewing bearing device?

In order to adjust the clearance caused by the installation error and wear of the track and the roller, the rolling bearing of the horizontal roller is usually sleeved on the eccentric shaft sleeve. The shaft sleeve is connected with the main shaft of the roller through a key, and the clearance between the roller and the raceway can be adjusted by rotating the main shaft.

17, the drum should be scrapped in any of the following circumstances:

① crack;

(2) The abrasion of the cylinder wall reaches 20% of the original wall thickness; (Calculation of bearing capacity loss)

(3) When the rope groove is worn more than 1/4 wire rope diameter and cannot be repaired.

Main lifting equipment in port and its classification

Gantry crane:

Bridge crane: A crane that takes the bridge as the load-bearing structure and can run horizontally along the track on the bridge. It consists of a hoisting mechanism, a trolley running mechanism and a cart running mechanism. Bridge crane is the most widely used and the largest number of rail cranes, and its rated lifting capacity ranges from several tons to several hundred tons. The most basic form is the universal hook crane.

Gantry crane: It is composed of portal metal frame, hoisting mechanism, cart running mechanism and trolley running mechanism, and can run along the ground in ports, docks and open-air freight yards to realize cargo loading and unloading operations.

Arm crane: Fixed cranes (portal cranes, fixed cranes) are widely used in cargo loading and unloading operations in ports, docks, freight yards and cargo transfer stations. The utility model has the advantages of simple structure, low working noise and easy maintenance. Hook and grab can be used to meet the loading and unloading requirements of different goods.

Mobile: Tire crane is a crane that installs lifting devices and equipment on specially designed bicycle tire chassis, which is called tire crane.

Buoyancy crane: an underwater cantilever crane, which uses a special buoy as a supporting and operating device, floats on the water surface and can sail or tow along the waterway. Widely used in Haihe port, it can independently complete the loading and unloading operations from ship to shore or ship to ship. Floating cranes can be divided into three types according to the working characteristics of their working devices: full rotary floating cranes, partial rotary floating cranes and non-rotary floating cranes.