maintenance and inspection of single girder bridge crane

Check the hook

• There is not crackle in hook of single girder bridge crane and sliding wheel shaft. Thread does not appear loose, bearing does not abrade and a crack must be replaced immediately.
• After the plate hook riveting, The gap between the plate and the plate is not more than 0.3mm.
• When the degree of critical section is more than 10% of the original height, that should be replaced.
• To do the hook test after maintenance, lift up the object with rated load of 1.25 times lasting for 10 minutes. As a result, the elastic opening of the hook is lower than the 0.25% of the size of the hook. And there is no permanent deformation and cracks after unloading.

Wirerope

• Check the number of broken wires in 1 lay. If more than 10% of the total number of steel wire, it should be replacement.
• When the attrition rate of steel wire is higher than that of the original diameter 40%, the whole wire rope is treated as scrap.
• The shrinkage of wire rope to 70% of the diameter of the rope and the rope core exposed, it should be scrapped.
• Clean the wire rope with kerosene. Use wire rope grease dip and coating to saturation.

Repair of pulley block

• The pulley shaft can not crack. The attrition rate of shaft neck should be no more than 30% of the original diameter, the degree of conic is not higher than 5%. If all the conditions are not met, it should be replaced.
• Check pulley groove shape according to sample. Wear is not higher than the wall thickness of 30%, otherwise it is discarded and replaced.
• After crane overhaul, the shaft hole of the defect can not be greater than 0.25cm² and the depth is less than 4mm.

Hoist roller

• When the lever of rope groove wear is higher than 2mm, it should be replaced. The thickness of the roller is not less than 81% of the original thickness after the overhaul.
• The center line of the roller shaft keep parallel with the bearing surface and center line in the two ends of the roller deviate less than 0.15mm.
• Ensure that there is no crack on the surface of the roller, the degree of loss of roundness is not obvious and the clamp screws should be tightened.
• There is no crack on the roller shaft. After the overhaul, if the degree of wear isn’t higher than that of 5% of the original standard diameter, it should be replaced.