Tower crane maintenance Tips
Repair and maintenance of metal structures
1. Strict implementation of crane steel structure scrapped.
2. The structure of the main force should be checked by metal fatigue strength, weld cracks, structural deformation, breakage, etc., critical welds and base metal weld heat affected zone of the main structure of the force should be checked, if found abnormal, it should be treated. Check the structural members according to the following procedure.
(A) Daily inspection: tower crane after every 80 hours should be a routine check. Tower crane driver in the shift, you should check the joints fastening bolts, if loose should be tightened.
(B) When the tower crane abnormal sounds, or misuse occurred, or discover the tower crane safety protection device failure, etc., should be checked, and make records.
(C) When a project is completed, after the demolition of tower crane, by engineering and technical personnel and professional maintenance staff conduct a detailed examination and make records.
3. During transport should be managed to prevent structural deformation and collision damage.
4. stencilled paint every six months to once a year. Before painting should be divisible rust, oil and other contaminants metal surface.
Rope and Maintenance
1. Rope during use, should prevent the rope looped, kink, bend or glue debris to prevent mechanical rubbing or other debris.
2. The tower crane installed (prior to use) to deal with the rope lubricated with graphite grease smear again, after the wire rope lubrication Press "Crane lubrication Tables".
3. The overall design of the tower crane with a rope does not allow an indefinite lifespan, one of the following conditions should be scrapped:
a. Rope 6 × 19-d (d wire diameter) in the number of broken wires 6d length of more than 5, in the 30d number of broken wires the length of more than 10.
b. rope 6 × 37-d (d wire diameter) in 6d length of more than 10 the number of broken wires in the 30d number of broken wires the length of more than 19.
c. rope close together, even in the number of broken wires 6d length of not more than 5, it should be scrapped.
d. Although there is no broken wire rope, but the rope wear reaches 40% of the diameter of the wire rope or reduced relative to the nominal diameter of 7% or more, or rope significant bending.
e. rope loss of normal shape, resulting in deformities, such as waves, cage-like distortion, extruded strands, wire extrusion, rope diameter larger local, kink, rope diameter smaller partial, partially crushed, bent.
f. rope diameter by a special thermal effect occurs when an external identifiable color.
Note: When lifting molten metal or hot acid solution, explosives, flammable when, halve the number of broken wire scrap. The specification does not mention the implementation according to the provisions of GB5972.
Maintenance and repair of mechanical parts
1. Routine maintenance
(1) keep clean bodies, timely cleaning each part dust;
(2) Check the gearbox oil, such as lower than the predetermined oil level should be timely refueling;
(3) Check the gearhead can freedom exhaust ventilation plug whether, if blocked, should be clear;
(4) Check the brake performance, as insensitive and reliable should be timely adjusted;
(5) Check the bolts at each connection, if timely fastening and loosening and additions;
(6) Check the safety equipment, such as found in the case of failure should be adjusted;
(7) Check all parts of the rope and pulleys, if found excessive wear should be timely treatment;
(8) Check the lubrication of lubrication, time to add grease.
2. Minor repairs (Tower Crane carried out after 1000 hours of operation)
(1) routine maintenance work;
(2) dismantling the gear reducer cleaning, adjusting backlash;
(3) Cleaning open drive gear, adjusted smear grease;
(4) Check and adjust the rotary bearing means;
(5) Check and adjust the brakes and safety devices;
(6) Check the hook, pulleys and rope wear, adjustment, repair and change, if necessary.
3. The repair (tower crane work performed after 4000 hours)
(1) the work carried out minor repairs;
(2) repair or change damaged parts of each of the coupling;
(3) Repair or replacement of the brake shoe;
(4) Replace the wire rope and pulleys;
(5) Check the rotary bearing portions of the connecting bolts and replace if necessary Note: when replacing the use of high-strength bolts;
(6) rust, paint.
4. Overhaul (tower crane to work 8000 hours later)
(1) minor repairs and the repair work;
(2) Repair or replacement of the brake wheel, brakes, etc;
(3) Repair or replacement of gear assembly;
(4) Repair or replacement of the rotary support assembly.
Other major components of the maintenance and repair
1. Brake Parts one of the following conditions should be scrapped:
(2) 50% of the brake pad friction pad wear volume of material thickness;
(3) brake wheel surface wear reaches 5mm ~ 2mm;
(4) plastic deformation of the spring;
(5) a system of levers air travel more than about 10% of its rated travel.
2. Hook ban welding, one of the following conditions should be scrapped:
(1) with 20 times the magnifying glass to observe the surface crack and break;
(2) a threaded portion and a tail hook and other dangerous sections and tendons hook permanent deformation;
(3) the amount of wear lanyard section at more than 10% of the original high;
(4) The amount of wear of the mandrel having a diameter of more than 5%;
(5) the opening of an increase of 15% over the original size.
3. reels and pulleys, one of the following conditions should be scrapped:
(1) rim cracks and breakage;
(2) drum wall wear volume of the original wall thickness of 10%;
(3) the amount of wear of the bottom rope pulley exceed 25% of the corresponding rope diameter.
4. The wheel of the following conditions should be scrapped:
(2) the thickness of the wheel tread wear amounted to 15% of the original thickness;
(3) the thickness of the wheel rim wear volume of 50% of the original thickness.
5. Operation driver must always check the security level limiter sensitive and effective case, as found defective and should adjust or repair, must not be allowed to tear down the line limiter.
Maintenance slewing ring device
(1) slewing ring mounting bracket (lower support ring and placed on transposon surface of the inner ring holder nest bottom surface) must have sufficient rigidity, the mounting surface should be flat. Slewing ring bearing assembly should be carried out prior to the stress treatment, to reduce the slewing ring bearing deformation. Assembling bearings and slewing ring contact surfaces must be clean.
(2) use should pay attention to changes in noise and rotational resistance moment of change, if any irregularities should be overhauled.
(3) the level of lifting or slewing ring must be stored, not vertical lifting or storage, to avoid distortion.
(4) the bolt is fully tightened before engaging gear inspection should be carried out, and its engagement position should meet the requirements of precision gears: gears contact pattern that is under slight braking operation after the tooth surface distribution in the tooth height direction not less than 25% in the tooth length is not less than 30%.
(5) tooth surface work 10 flights a debris should be cleared and re-coated with grease.
(6) In order to ensure the reliability of the work of the bolt, bolt preload to avoid the lack of the first 100 hours of work slewing ring and 500 hours, respectively, should check the pretension of the bolt. Then every 1,000 hours of work should be checked once pretension.
(7) slewing ring connecting bolts and nuts are made of high-strength bolts and nuts; double nut and lock.
(8) Tighten the nuts should topcoat lubricants threaded end bolts and nuts, and a torque wrench should be used uniformly in the circumferential direction of the symmetry tightened several times. Finally again tightened, each bolt tightening torque should be roughly uniform.
(9) on the slewing ring ring raceway surface parts are aligned cloth 4 cup oil, thereby adding to the grease Raceway. Under normal circumstances, slewing ring lubrication operation 50 hours once. Each refueling must add a little oil until oozing up from the seal.