The elastic base plates are made of rubber sheets, and their properties should meet the following requirements: a Shore hardness of 70 – 80 degrees, a tensile strength greater than 130 kg/cm², an elongation at break greater than 300%, and a compressive elastic modulus of 700 – 1200 kg/cm².
As the elastic base plates play a crucial role in absorbing vibrations and distributing loads, it’s vital to source high-quality rubber materials. Manufacturers usually conduct strict quality control tests during production to ensure these performance indicators are met. In large-scale crane installation projects, any deviation in the properties of the elastic base plates could lead to uneven stress distribution on the crane‘s supporting structure, potentially causing premature wear and tear or even structural damage over time.
(2) Processing of Pressure Plates
The pressure plates can be made of No. 3 ordinary carbon steel and processed and welded as required. At the fishplate, the size of the part of the pressure plate in contact with the track should be changed from 16 mm to 6 mm.
When fabricating the pressure plates, precision machining is essential. The change in size at the fishplate area is designed to better fit the track’s profile, reducing stress concentrations and ensuring a more stable connection between the crane and the track. Welding quality also needs to be closely monitored. Any welding defects, such as porosity or incomplete fusion, could undermine the overall strength of the pressure plate assembly, endangering the safety of the crane during operation.
(3) Track Straightening
Track straightening involves not only correcting the vertical bending of the track but also the lateral bending. When the track is not straight laterally, the crane wheels may get jammed during operation. Therefore, lateral bending correction is the key focus.
Specialized track straightening equipment is often employed in this process. Technicians use measuring tools like laser alignment devices to accurately detect the degree of bending in both vertical and lateral directions. For lateral bending, precise adjustments are made by applying controlled forces to gradually bring the track back to its proper alignment. This step is labor-intensive and requires experienced workers to ensure the highest level of accuracy.
(4) Fastening of Track Screws
The screws on the track must be tightened firmly. Spring washers should be added under all nuts. After tightening, the screw threads should protrude from the nut by at least 1.5 turns and be at most 10 mm below the track cleaning plate.
Proper screw tightening torque is crucial. Too little torque may cause the screws to loosen during the crane’s operation, leading to track misalignment. Excessive torque, on the other hand, can damage the screw threads or the nut itself. The addition of spring washers provides additional anti-loosening protection, compensating for any vibrations or small displacements that occur during the crane’s dynamic operation.
(5) Offset of Track Joints
The joint positions of two parallel tracks should be staggered, and the staggering distance should not be equal to the wheelbase of the front and rear wheels of the crane.
This offset design helps to distribute the load more evenly when the crane moves across the track joints. If the joints were aligned, the repeated impact at the same points during crane travel could accelerate track wear and potentially cause structural damage to the track system. Engineers carefully calculate the optimal staggering distance based on the crane’s specifications to minimize these negative effects.
(6) Pre-Commissioning Inspection
The inspection before commissioning should be carried out with all power sources cut off.
During this inspection, technicians thoroughly check all electrical connections, mechanical components, and safety devices. They look for any signs of damage during transportation or assembly, such as loose wires, bent parts, or malfunctioning sensors. This comprehensive check is the last line of defense before the crane is put into operation, ensuring that any potential hazards are identified and rectified in advance.
(7) Adjustment of Brakes
The adjustment of brakes should meet the following requirements:
The brakes should open and close smoothly, and the braking effect should be stable and reliable.
The brake for the hoisting mechanism should be 1.25 times the rated load and should not slip under static load.
For the running mechanism’s brakes, the adjustment should not be too loose or too tight. It is advisable to avoid any occurrence of vehicle slipping or impact.
Brakes are the most critical safety components of a crane. Technicians use specialized tools to adjust the brake pads’ clearance and the tension of the braking springs. For the hoisting brake, load tests are often conducted to verify its performance under different load conditions. The running brakes are fine-tuned based on the crane’s running speed and load distribution to ensure smooth starts, stops, and travel.
(8) Load Tests for Hooks
Static load tests and dynamic load tests should be carried out for the main hook and the auxiliary hook respectively.
During static load tests, weights corresponding to specified loads are gradually applied to the hooks, and the deformation and stress of the hook structure are closely monitored. Dynamic load tests simulate real working conditions, involving lifting, moving, and lowering the loads at different speeds. These tests help to detect any potential weaknesses in the hook design or manufacturing, such as fatigue cracks or insufficient strength, ensuring their reliability during actual use.
(9) Construction Site Cleanliness
During the crane installation construction, there should be no civil engineering work in the factory building, and the site should be thoroughly cleaned.
A clean construction site is essential for worker safety and the accuracy of installation. Construction debris could cause workers to trip or interfere with the precise alignment of crane components. Moreover, in the absence of other ongoing civil works, the installation team can focus solely on the crane installation tasks, reducing the risk of cross-project interference.
(10) Cleaning and Maintenance of Components
When assembling the crane, clean and lubricate the large and small traveling wheels and other components. The cleaned components should be classified and placed, and covered with plastic sheeting.
Cleaning removes any rust, dirt, or debris accumulated during manufacturing or storage, which could otherwise affect the smooth operation of components. Lubrication reduces friction between moving parts, extending their service life. The proper classification and covering of components prevent contamination and damage before they are installed into the crane.
(11) Safety Measures for High-Altitude Workers
Construction workers performing high-altitude operations must fasten their safety belts properly. It is strictly prohibited to throw tools, materials, etc. downward from a height.
High-altitude work is inherently risky. Safety belts are the primary means of protecting workers from falls. Regular training programs are usually in place to ensure workers are proficient in using safety belts correctly. The ban on throwing objects is to safeguard the safety of all personnel on the ground floor, as even a small tool dropped from a height can cause serious injury.
(12) Safety on Track Beams
When walking on the track beam, avoid walking directly on the track. At the same time, tighten the trouser legs to prevent getting caught or hooked by other objects and falling.
The track is a critical part of the crane’s operation system, and any accidental damage to it can disrupt the crane’s normal running. Tightening trouser legs is a simple yet effective preventive measure, minimizing the risk of contact with protruding parts or loose wires on the track beam.
(13) Preventing Displacement during Lifting
To prevent displacement at the bundling positions when hoisting the crane, cut holes of appropriate sizes at the corresponding positions on the platform plate of the main girder. Then, use sleepers to support the ribbed parts between the girders to avoid inward bending and deformation of the girders during hoisting.
This preparation work is carefully planned based on the crane’s structural design and lifting plan. The cut holes provide clearance for the lifting ropes, allowing for more stable bundling. The use of sleepers distributes the lifting forces evenly across the girder structure, protecting it from excessive deformation.
(14) Safety during Transportation and Lifting
During the transportation and lifting process, follow the command instructions. Do not leave the work post without permission. The construction warning areas demarcated during lifting are marked with restricted signs, and non-construction personnel are prohibited from entering.
Effective communication and strict discipline are the keys to ensuring safety during transportation and lifting. The person in charge of the lifting operation coordinates all actions, and each worker must be vigilant and responsive. The restricted areas are set up to keep bystanders at a safe distance, preventing any accidental injuries from falling objects or moving machinery.
In addition to these basic precautions, with the development of crane technology, more advanced installation requirements are emerging. For example, in modern intelligent crane installations, the integration of sensors and control systems requires extremely precise alignment and calibration. These sensors, which are used for functions like load monitoring, position detection, and anti-collision, need to be installed in a dust-free and vibration-free environment to ensure their accuracy.
During the installation of electric cranes, special attention must be paid to the electrical wiring layout. High-voltage cables need to be separated from low-voltage control lines to avoid electromagnetic interference. The grounding system of electric cranes also needs to be more elaborate, with multiple grounding points to ensure the safety of electrical operations and protect against electrical leakage.
As for large-tonnage cranes, the foundation design becomes even more critical. Engineers need to conduct in-depth geological surveys to design foundations that can withstand the huge loads. Reinforced concrete foundations with proper reinforcement ratios are often used, and the installation process involves strict quality control of concrete pouring, curing, and foundation bolt tightening.
Moreover, in the context of sustainable construction, the selection of crane materials is also evolving. More environmentally friendly and recyclable materials are being considered, not only to reduce the environmental impact but also to potentially lower long-term maintenance costs. These new materials often have different mechanical properties, which require installation teams to adapt their techniques and procedures accordingly.
In the international market, different regions may have specific safety standards and regulations for crane installation. For example, in some European countries, stricter environmental protection regulations may affect the choice of lubricants and cleaning agents used during installation. In some Asian countries with high seismic activity, additional seismic-resistant design requirements are imposed on crane installations. Installation teams need to be well-versed in these regional differences to ensure compliance and the safe operation of cranes across different locations.
Another aspect is the maintenance and inspection plan formulated during the installation process. A comprehensive plan should cover regular inspections of key components, lubrication schedules, and the replacement of wearing parts. With the help of modern digital technology, some cranes are now equipped with remote monitoring systems, which can transmit real-time operation data to maintenance teams. Installation technicians need to ensure that these systems are properly installed and configured from the very beginning, integrating them seamlessly into the overall crane installation project.
The training of crane operators also cannot be ignored. Alongside the installation work, proper training programs should be provided to operators, teaching them about the new features and safety precautions of the installed crane. Operators need to be familiar with the crane’s control system, emergency stop procedures, and how to handle abnormal situations during operation, which is an integral part of ensuring the long-term safe use of the crane.
