Lifting machinery

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Chapter 4: Lifting Machinery Section 1: General Provisions 1. Preparation before operation: The internal combustion engine, electric motor, and hydraulic system of the crane shall be handled in accordance with the relevant provisions in Sections 1, 5, and 6 of Chapter 3. 2. When the crane is in operation, there must be sufficient working space; the ground should be level and solid, with no obstacles within the range of movement of the crane’s boom and its rotation radius. 3. All types of cranes must be equipped with signal devices such as clearly audible horns, electric bells, or whistles. Brightly colored markers are applied to the hook, boom, and counterweight rotating parts. 4. Before starting the work, it is necessary to gain a comprehensive understanding of the working environment, the roads to be used, overhead power lines, buildings, as well as the weight and distribution of various components. 5. In case of severe weather conditions such as winds of force 6 or above, heavy rain, heavy snow, or dense fog, outdoor operations of the crane should be stopped. 6. Cranes must not operate near overhead power lines; if working near such lines is necessary due to site constraints, safety measures must be taken. The safety distance between cranes and overhead power lines must not be less than the values specified in Table 4–1. Safe distance between cranes and overhead power lines (m) Table 4-1: Voltage of power lines (kV). For voltages below 1, the safe distance is 1–1.5 m; for 20–40 kV, it is 2–4 m; for 60–110 kV, it is 4–6 m; and for 220 kV, it is 6 m. The minimum allowed distance perpendicular to the power line is 1.5 m, while the minimum allowed distance horizontal to the power line is 2–4 m. 7. The steel ropes used in cranes must be accompanied by technical certification documents issued by the manufacturer. If no certificate is available, it must pass testing before it can be used. 8. The wire ropes used in cranes must have a structure, specifications, and strength that meet the requirements of that type of crane. The steel wire rope on the drum should be firmly connected and neatly arranged; when releasing the rope, at least three turns should remain on the drum. When retracting or extending the steel wire rope, care should be taken to prevent it from knitting, twisting, bending, or becoming tangled. Kinked or deformed steel cables must not be used. 9. When the steel wire rope is secured by tying, the length of the tied portion shall not be less than 15 times the diameter of the steel wire rope, nor less than 300 mm, and fine steel wires shall be used to tie this portion. When using rope clamps for fixation, the number must be no less than 3. The number of shackle sizes should match the diameter of the steel wire rope (see Table 4-2). The distance from the last clip to the end of the rope shall be not less than 140 mm. The rope clip saddle (splint) should be located on the side of the steel wire rope that is under stress during operation, and the “U”-shaped bolts must be at the end of the steel wire rope; they must not be arranged in opposite directions. After the rope clamp is in place, tighten it again once the steel wire rope is under stress; it should be tightened enough to compress about 1/3 of the diameter of both ropes. The tightness must be checked frequently during the operation. Number of shims required based on rope diameter Table 4–2: Steel rope diameter (mm): Below 10, 10–20, 21–26, 28–36, 36–40. Minimum number of shims (pieces): 3, 4, 5, 6, 7. Shim spacing (mm): 80, 140, 160, 220, 240. 10. Before starting work each shift, all visible parts of the steel rope as well as its connection points should be inspected. The wire rope shall be replaced when surface wear or corrosion reduces its nominal diameter by 7%, or when it is deformed, or when the number of broken wires within a specified length range reaches the values specified in the table below. Replacement criteria for broken wires in steel ropes (d = rope diameter) Table 4-3: Length of broken wires in steel ropes. Rope type, structural pattern, range: 6×19 + 16×37 + 16×61 + 118×19 + 1; Twisted type: 6d, 30d, 1019, 1938, 2958, 2754; Straight twisted type: 6d, 30d, 510, 1010, 1915, 3018, 27. 11. It is strictly prohibited to weld repairs to the hooks and slings of cranes; they must be replaced in any of the following situations: (1) Cracks on the surface ； (2) Permanent deformation in the critical sections and necking areas ； (3) The cross-sectional wear at the hanging rope location exceeds 10% of the height ； (4) The wear of the hook bushing exceeds 50% of its original thickness, and the wear of the spindle (pin) exceeds 3–5% of its diameter. (5) The increase in the hook opening degree exceeds 15% ； (6) The hook’s torsional deformation exceeds 10%. 12. The brake drums of the crane’s brakes should be replaced when their surface wear reaches 1.5–2.0 mm (using the higher value for larger diameters and the lower value for smaller diameters), or when the brake bands are worn by more than 50% of their original thickness. 13. A regular inspection must be carried out annually; in addition to checking all components, static and dynamic load tests should also be performed. II. Precautions during operation 1. Before performing actions such as rotating, adjusting the boom angle, moving the crane, or lifting and lowering the hook, the operator should give a sound signal as a warning. 2. When operating a crane, the operator should work closely with the supervisor. The operator must strictly follow the signals given by the commander; if the signals are unclear or incorrect, the operator may refuse to carry out the instructions. If an accident occurs due to faulty command, the commander shall be held responsible. 3. For cranes with a control room located far above the ground, when normal command and control are difficult, two commanders—one at a high altitude and one on the ground—can be assigned, or effective communication methods can be used for command and control. 4. Safety protection devices of the crane, such as the luffing indicator, torque limiter, and various travel limit switches, must be complete, in good condition, sensitive, and reliable; they shall not be adjusted or removed arbitrarily. It is strictly prohibited to use limit devices in place of control mechanisms. 5. When the crane is in operation, no one shall stay or pass under the load. It is strictly prohibited to use non-passenger cranes to transport people. 6. Lifting machinery must be operated in accordance with its specified lifting capacity; it is not allowed to lift loads beyond this capacity or objects of unknown weight. 7. It is strictly prohibited to use cranes for pulling, lifting at an angle, or lifting heavy objects that are buried underground or stuck to the ground. Concrete components or formwork cast on site must be fully loosened before they can be lifted. 8. When lifting heavy objects, they must be tied securely and stably; no miscellaneous items should be placed on or hung from the object. Miscellaneous materials or items must be firmly secured using a lift cage or steel wire ropes before they can be lifted. Objects marked with binding positions or indicators should be tied at the indicated locations. The angle between the binding steel wire rope and the object must not be less than 30°. 9. Before operating a crane in rainy or snowy weather, it should first undergo a test lift; operation can proceed only after confirming that the brakes are sensitive and reliable. 10. When lifting a load at full capacity or near full capacity, the crane should first lift the load to a height of 200–500 mm above the ground and then stop lifting it, in order to check the stability of the crane, the reliability of the brakes, the stability of the load, and the firmness of the bindings. It can be raised again only after confirmation that everything is correct. Rope ties must be used for heavy objects that may shake. 11. The lifting and lowering speed of heavy objects should be uniform. Rapid acceleration and deceleration as well as sudden braking are strictly prohibited. The left and right turning movements should be smooth; no reverse movement should be made until the turning has come to a complete stop. For cranes that do not use gravity-driven descent, it is strictly prohibited to allow them to descend freely under load. Section 2: Tower Cranes I. The track foundation of the crane shall meet the following requirements: 1. Subgrade bearing capacity: For light-duty cranes (with a lifting capacity of 30 kN or less), it should be 60–100 kPa ； Medium (lifting capacity 31–150 kN) should be 101–200 kPa ； For heavy types (with a lifting capacity of 150 kN or more), it should be 200 kPa or more. 2. A gauge tie shall be installed every 6 meters; the allowable deviation of the gauge is 1/1000 of the nominal value, and shall not exceed ±3 mm ； 3. In both the longitudinal and transverse directions, the slope of the top surface of the rail shall not exceed 1/1000 ； 4. The gap at the rail joints must not exceed 4 mm, and they should be offset from the joints on the other side by a distance of at least 1.5 m. The joints should be positioned on sleepers, and the height difference between the two rail tops must not be more than 2 mm ； 5. A buffer stop must be installed 1 meter from the end of the track, and its height should not be less than the radius of the traveling wheel. A limit switch striker must be installed 2m from the end of the track ； 6. The fishplate connection bolts should be tightened, and the shims should be securely fixed. II. The concrete foundation of the crane shall meet the following requirements: 1. The concrete strength grade shall be no less than C35 ； 2. The allowable deviation for the flatness of the base surface is 1/1000 ； 3. The position, elevation, and verticality of the embedded components, as well as the construction methods, meet the requirements specified in the factory instructions. III. The track foundation or concrete foundation of the crane must pass inspection before it can be put into use. IV. Slopes and drainage facilities should be constructed on both sides of the crane’s track foundation as well as around the concrete foundation, and a certain safety distance should be maintained from the excavation pit. V. The metal structure of the crane, its tracks, and the metal enclosures of all electrical equipment must be equipped with reliable grounding systems, with a grounding resistance not exceeding 4Ω. VI. The disassembly and assembly of cranes must be carried out by specialized teams that hold qualification certificates for such work issued by the construction administration authorities, and technical and safety personnel must be present to oversee the process. VII. Before disassembling or assembling the crane, it is necessary to prepare procedures for the disassembly/assembly work, quality requirements, and safety measures in accordance with the relevant regulations issued by the manufacturer. These documents must be approved by the company’s technical supervisor before they can be used as a technical plan for the disassembly/assembly work, and they should be communicated to all workers involved in the task. VIII. The inspection items prior to disassembly and assembly operations shall meet the following requirements: 1. The subgrade and track laying, or concrete foundation, shall comply with technical specifications ； 2. Inspect all mechanisms, components, structural welds of the crane being disassembled or assembled, as well as the bolts and pins in critical areas, the winch and steel cables, hooks, lifting attachments, and electrical equipment and wiring, in order to eliminate potential hazards before proceeding with the disassembly or assembly work ； 3. Inspect the hydraulic cylinders and hoses of the jacking hydraulic system of the self-elevating tower crane, as well as the jacking frame structure, guide wheels, jacking feet (crawling claws), etc., and address any existing problems promptly ； 4. Inspect the main and auxiliary ground anchor frames used in the rotating tower body method, the winch cables for lifting the tower body, as well as the braking system of the lifting mechanism; they may be used only after verification that everything is in order ； 5. Inspect the tools, safety belts, safety helmets, etc., used by the assembly and disassembly personnel; replace those that do not meet the standards immediately ； 6. The auxiliary machinery such as cranes and transport vehicles used in the disassembly and assembly operations must be in good condition, and their technical specifications must meet the requirements of these operations ； 7. The power supply voltage at the assembly and disassembly site, the transportation routes, and the work area must all meet the requirements for carrying out assembly and disassembly operations ； 8. The establishment of safety supervision positions and the implementation of safety technical measures meet the required standards. 9. The disassembly and assembly of cranes should be carried out during the day. Operations should be halted in case of severe weather conditions such as strong winds, heavy fog, and rain or snow. 10. Commanders should be familiar with the disassembly and assembly plans, comply with the relevant processes and operating procedures, and use clear command signals to give instructions. All personnel involved in the disassembly and assembly tasks must follow instructions. If the command signals are unclear or incorrect, work should be stopped until the instructions are clear before resuming operations. 11. When entering the work site, personnel responsible for disassembly and assembly must wear safety protective equipment; when working at heights, they must fasten their safety belts. They should be familiar with and strictly follow the relevant disassembly and assembly procedures and operating rules. In the event of any abnormal situations or difficult problems, they must report them to the technical supervisor promptly, and must not act on their own initiative, in order to prevent accidents resulting from improper handling. 12. When disassembling or assembling the jib with a swiveling top and a trolley for amplitude control, it is necessary to follow the disassembly and assembly instructions provided in the factory manual, and the balance of the crane must be maintained. 13. In structures connected using high-strength bolts, bolts manufactured by the original manufacturer should be used; self-made bolts must be accompanied by proof of satisfactory quality tests, otherwise they shall not be used. When tightening the connection bolts, a torque wrench or a special wrench should be used, and they should be tightened in accordance with the assembly technical requirements. 14. During disassembly and assembly operations, in the event of sudden changes in weather, power outages, mechanical failures, or other unexpected situations that prevent continued work for a short period of time, it is necessary to bring the parts that have been disassembled or assembled to a stable state and secure them firmly. Only after checking to ensure there are no hidden hazards can work be stopped. 15. When installing the crane, it is necessary to ensure that the traveling buffer stops and limit switch contacts are installed firmly and reliably, and that all safety devices such as railings, platforms, handrails, and protective guards in various areas are properly installed. 16. When demolishing cranes that cannot be removed by normal methods due to damage or other reasons, it is necessary to follow the safety demolition plan approved by the technical department. 17. During the installation of cranes, technical inspections must be carried out in stages. After the entire machine has been installed, a technical inspection and adjustment of the whole unit are required. The movements of all mechanisms should be accurate and smooth, without any abnormal noises; the braking system must be reliable, and all safety devices should be sensitive and effective ； Under no-load conditions, the allowable deviation for the verticality of the tower body and foundation planes is 4/1000. After passing the stage-by-stage inspections as well as the overall inspection, an inspection record must be filled out; it can only be put into use after being reviewed and approved by the technical supervisor. 18. When lifting or lowering the crane tower, the following requirements must be met: 1. During the lifting operation, there must be a dedicated person to give instructions, another dedicated person to monitor the power supply, another dedicated person to operate the hydraulic system, and another dedicated person to tighten or loosen the bolts. Morning workers are not allowed to ascend to the operating platform of the jacking frame. Only one person is allowed to operate from the control room, and they must follow the instructions given by the supervisor ； 2. Lifting operations should be carried out during the day; if work must be done at night in special circumstances, adequate lighting must be provided ； 3. Lifting operations shall not be carried out when the wind force is at level 4 or above. If the wind force suddenly increases to level 4 during operation, work must be stopped immediately, and all connection bolts between the upper and lower tower sections should be tightened ； 4. Before lifting, the cable should be loosened in advance; its length should be greater than the total lifting height, and the cable reel should be secured properly. Tighten the cable in a timely manner when descending ； 5. When lifting or lowering, it is necessary to adjust the gap between the rollers of the jacking frame and the standard sections of the tower. The boom and counterweight arm must be brought into a balanced state as specified, and the slewing mechanism must be braked. When it is difficult to remove the last connecting bolt (pin) between the slewing platform and the standard sections of the tower, the bolts in the diagonal direction should be reinserted first, followed by other corrective measures. Do not use the rotation of the boom to loosen bolts (pins) ； 6. When lifting or lowering, after the lifting feet (claws) are in place, a safety pin should be inserted before proceeding to the next step ； 7. After the lifting is complete, all connection bolts should be tightened to the specified torque, the hydraulic control lever should be returned to the middle position, and the power supply to the hydraulic lifting mechanism should be cut off. 19. The attachment anchoring of cranes shall meet the following requirements: 1. The load-bearing capacity of the anchorage points in the building to which the crane is attached must satisfy the design requirements of the crane. The arrangement of the attachment rod systems and the distances between them shall be carried out in accordance with the instructions provided with the product at the time of manufacture. If there are changes, a new design should be created ； 2. When installing the attachment frames and rods, a theodolite should be used to measure the verticality of the tower, and the attachment rods should be employed for adjustment; the allowable deviation in verticality below the highest anchoring point is 2/1000 ； 3. When installing the attachment frame and attachment supports, the inclination angle of the attachment rods shall not exceed 10° ； 4. The attachment frame should be installed at the joints of the standard tower sections to tighten the cross-section. The tower diagonals should be reinforced in the absence of bracing ； 5. When the tower body is jacked up to the specified anchoring spacing, anchoring devices connected to the building should be added promptly. The height of the tower above the free end of the anchoring device shall comply with the factory specifications ； 6. During crane operations, the anchoring device should be checked frequently; if any looseness or abnormalities are detected, operations must be stopped immediately. Work shall not resume until the fault has been resolved ； 7. When dismantling the crane, the corresponding anchoring devices should be removed as the tower body is lowered. It is strictly prohibited to remove the anchoring device before lowering the tower ； 8. It is strictly prohibited to install or remove anchoring devices in case of winds of force 6 or above ； 9. The installation, removal, inspection, and adjustment of anchoring devices must be carried out by designated personnel. Safety belts and helmets must be worn during these tasks, and the relevant safety regulations for working at heights must be followed ； 10. When a track crane is used in a fixed installation, the load-bearing capacity of the track foundation should be increased, the power supply to the traveling mechanism should be cut off, and supports should be installed to prevent the traveling wheels from moving. 20. When climbing inside a crane, the following requirements must be met: 1. Climbing operations shall be carried out during the day. Operations should be stopped when the wind force is at level 5 or above ； 2. During internal climbing, communication between the upper and lower parts of the aircraft, as well as between higher and lower floors, should be strengthened. In the event of any faults or abnormalities, the aircraft must be stopped immediately for inspection; climbing should not continue until the fault is resolved ； 3. During internal climbing, it is strictly prohibited to perform any actions such as lifting, rotating, or changing the amplitude of the crane ； 4. After the crane has ascended to the designated floor, the support beams or legs at the base of the tower should be removed immediately, and it should be fixed to the floor using an internal climbing frame; additionally, the guiding device should be pressed firmly in place or secured with wedges ； 5. The fixed interval for internal climbing tower cranes should not be less than 3 floors ； 6. For floor slabs of floors with fixed internal climbing frames, additional columns should be installed beneath the slabs for temporary reinforcement. Support pillars should also be installed for temporary reinforcement on the two floors below the floor where the crane base support beam is located ； 7. After each internal climb, the openings remaining on the floor slab should be immediately sealed using reinforced concrete ； 8. After the crane has completed the internal climbing operation, it is necessary to check the fixation of the internal climbing frame, the tightness of the base support beams, and the stability of the temporary floor supports. Only after confirming that everything is secure can the lifting operation proceed. 21. After each month or following periods of continuous heavy rainfall, a comprehensive inspection of the track foundation should be carried out promptly. The aspects to be checked include: gauge deviation, the inclination of the rail top surface, elastic settlement of the track foundation, the straightness of the rails, and the track’s performance in terms of smooth operation. For concrete foundations, it is necessary to check for uneven settlement. 22. All safety devices on the crane must be kept sensitive and functional; any defective safety device should be repaired or replaced promptly. After all safety devices have been adjusted, they should be sealed (with wax or lead seals) to keep them in place; unauthorized adjustments are strictly prohibited. 23. The distribution box should be located in the middle of the track. The power circuit shall be equipped with phase-error and phase-loss protection devices as well as an emergency power-off switch. The cable reel must be flexible and functional, and it is not allowed for the cable to drag behind it. 24. When a crane is operating near radio stations, television stations, or other antennas that emit strong electromagnetic waves, the workers who come into contact with the hook must wear insulating gloves and shoes, and a temporary discharge device should be attached to the hook of their helmets. 25. When there are two or more cranes at the same construction site, the distance between any adjacent parts of the cranes (including the distance to the load) must be maintained at no less than 2 meters. 26. Before operating the crane, it is necessary to check that the track foundation is straight and free from settlement, that the bolts connecting the fishplate joints as well as the spikes are tight, and that any obstacles on the tracks are removed. The track clamps should be released and secured in place. 27. The key inspection items prior to startup shall meet the following requirements: 1. The appearance of the metal structure and operating mechanisms is normal ； 2. All safety devices and indicator instruments are complete and in good condition ； 3. The oil levels in all gearboxes and hydraulic oil tanks are within the specified ranges ； 4. The connection bolts in the main areas are not loose ； 5. The wear condition of the wire rope and the winding around each pulley are in compliance with regulations ； 6. The power supply cable is undamaged. 28. Before power is supplied, the handles of all controllers should be in the zero position. When the power is turned on, a voltage tester should be used to check the metal components to ensure there is no leakage before the machine can be used. 29. Before starting work, an idle run should be conducted to check whether all operating mechanisms are functioning properly, whether there is any noise or abnormal sounds, and whether the brakes and safety devices of each mechanism are effective. Work can only begin after confirming that everything is normal. 30. When lifting heavy objects, the total weight of the object and the lifting equipment shall not exceed the lifting capacity specified for that crane’s range. 31. The appropriate operating speed should be selected based on the weight being lifted and the conditions at the site. When operating the various controllers, it is necessary to start from the stop point (zero) and gradually increase the speed step by step; operating beyond the designated range is strictly prohibited. When changing the direction of operation, turn the controller handle to the zero position; wait until the motor has stopped before switching to the other direction. It is not allowed to change the direction of operation directly, or to alter the speed or apply braking suddenly. 32. Before the hook reaches the lifting limit, or before the crane trolley or traveling crane moves to the limit device, it should slow down and come to a stop at an appropriate distance from the limit device (at least 1 meter for the hook, and at least 2 meters for the traveling wheels). It is strictly prohibited to use limit devices as control switches to stop operation. 33. The lifting, slewing, and traveling of a boom crane can be carried out simultaneously, while luffing must be done separately. The area that has been adjusted should be inspected after each adjustment. If load-induced luffing is permitted, luffing is strictly prohibited when the load reaches 90% or more of the rated lifting capacity. 34. When lifting heavy objects, free fall is strictly prohibited. When the heavy object is being placed in position, a slow positioning mechanism can be used, or brakes can be employed to lower it slowly. 35. When lifting heavy objects for horizontal movement, they should be at a height of more than 0.5 m above the obstacles they cross. 36. For cranes without a central collector ring and whose lifting mechanism is not installed on the rotating part, they must not rotate continuously in one direction during operation. 37. Cranes equipped with upper and lower control systems shall not be used simultaneously with both sets. 38. During operation, in the event of a power outage or voltage drop, the controller should be immediately switched to the zero position and the power supply disconnected. If there is a heavy object hanging from the hook, the brake should be used repeatedly, adjusting its tension slightly, to allow the object to descend slowly to a safe location. 39. Cranes equipped with an eddy current braking speed control system shall not be used in low-speed gear or at a slow positioning speed for extended periods of time. 40. In case of winds of force 6 or above, or gusts, during operations, work must be stopped immediately; the rail clamps should be locked, the brakes of the rotating mechanism should be fully released, and the boom should be able to rotate with the wind. For lightweight pitch jib cranes, the boom should be lowered and locked together with the tower structure. 41. During operation, when the operator temporarily leaves the control room, the power supply must be turned off and the rail clamps must be locked. 42. Special elevators for carrying people on cranes must not be overloaded, and their rope break protection devices must be reliable. The elevator must not be operated while the crane is in use. When the elevator is out of use, it should be lowered to the bottom of the tower shaft and must not remain suspended in the air for long periods. 43. After the work is completed, the crane should be parked in the middle of the tracks, its boom should be turned in the direction of the wind, and the slewing brake should be released. The trolley and counterweight should be set in a non-operational state, while the hook should be raised to a height of 2–3 meters above the top of the boom. 44. When shutting down the crane, each controller should be turned back to zero, the switches should be turned off one by one, and the doors and windows of the control room should be closed. After leaving the crane, the track clamps should be locked to secure the crane to the tracks, the main power switch should be turned off, and the high-altitude indicator light should be turned on. 45. When maintenance personnel climb to high areas such as the tower body, boom, and counterweight arm for inspection or repair, they must wear safety belts. 46. During the cold season, the motors, electrical cabinets, resistor boxes, brakes, and other components of cranes that are not in use should be properly covered. 47. On boom-type and self-elevating tower cranes that are not yet attached, no signboards shall be hung on the tower.