The preparation work for medium repair and overhaul is carried out within 5-6 months from the preparation of the damage report form to the shutdown of the double-girder crane for repair.
The damage report form is prepared based on the records made during the inspection of the double girder crane. In order to fill in these records, there is a special row in the maintenance and inspection book for repairs to be made. Manufacture and obtain necessary reserve parts according to damage report form.
When a double-girder crane is stopped for repair, its mechanism and steel structure must be inspected. At this time, special attention must be paid to:
a. The wheel positions of both the double-girder crane and the trolley to determine whether they are installed correctly and whether their spindle centers must be corrected;
b. Radial clearance in the gear transmission of the double-girder crane, whether the gears have full meshing and whether the rotating shaft has no deflection;
c. Whether the rotating shaft of the double-girder crane mechanism jumps and whether the axis of the rotating shaft connected by the coupling coincides;
d. The status of the lubrication system of the double-girder crane and whether there is no oil leakage;
e. The condition of the steel structure of the double-girder crane.
f. Double girder crane hook wear degree.
Safety inspection specifications for double girder cranes
Safety Inspection of Double-Girder Overhead Crane In order to ensure the safe operation of the overhead crane, some routine safety inspections need to be carried out during the operation of the crane. The inspection items and key points are as follows:
1. The lifting height limiter, travel limit switch and various interlocking mechanisms have normal performance and are safe and reliable.
2. All main components meet safety requirements: the opening increase is less than 15% of the original size, the torsional deformation is less than 10%; the plate hook bushing wear is less than 50% of the original size, the plate hook spindle wear is less than 5%, and there is no peeling, burr, or welding repair. There are no obvious defects in the crane hook hanger and pulley. The amount of steel wire wear and corrosion on the surface of the steel wire rope is less than 40% of the steel wire diameter, and the broken wires within one lay pitch are less than 10% of the total number of wires. There are no broken ends, no obvious thinning, and no core protrusion, dead corner twisting, extrusion deformation, annealing, and burning. The clips, pressure plates, and wedges that connect and fix the ends of the wire rope are in good condition and are not loose. There are no less than 2 pressure plates and no less than 3 clips. The drum has no cracks, and the connection and fixation are not loose; the drum wall wear is less than 20% of the original wall thickness; the safety roll is no less than 2 turns, and the diameter ratio of the drum to the wire rope meets the requirements. The balance wheel is well fixed and the wire rope should meet the requirements. The brake has no cracks, looseness, or serious wear. The brake gap is of equal size on both sides and has sufficient braking force. The wear of the brake band is less than 50% of the original thickness.
