The installation of crane tracks is a crucial process that ensures the proper alignment and operation of overhead cranes. The following detailed steps outline the installation procedure:
1. Line Marking
Using the crane girder’s positioning axis as a reference, deploy a theodolite to establish baseline points. At a distance of 60mm from the track centerline, mark reference points at intervals of 2 meters along the longitudinal position of the girder. Additionally, place markers at each column to create a baseline for track alignment.
2. Track Fabrication
Track fabrication involves several key steps, including cutting, drilling, straightening, and trimming.
Cutting and Drilling: Ensure precise measurement for cutting and drill holes based on the design.
Straightening: Use a full-length string line or a steel ruler to identify bent sections. Employ a track straightener to rectify these bends. When straightening, overextend slightly and allow the track to stabilize before releasing. If necessary, lightly hammer the raised areas with a sledgehammer. Verify alignment from both vertical and lateral perspectives to ensure compliance with specified tolerances.
3. Track Placement
Before placement, lay 20mm thick wooden blocks on the crane girder as a temporary base. Position the required elastic base plates according to the design specifications.
Lift the pre-fabricated tracks (four per side) using an 8-ton truck-mounted crane and carefully place them on the girder.
4. Track Alignment and Tightening
Preparation: Prepare all required materials, including bolts, washers, clamping plates, and fishplates. Place these in a tool bag on the crane girder for easy access.
Preliminary Alignment: After setting the elastic base plates, remove the wooden blocks beneath the tracks. Use fishplates to connect individual track sections. Ensure that the gap between adjacent tracks does not exceed 2mm.
Rough Alignment: Using the previously marked baseline, align the tracks roughly into a straight line. Temporarily secure them with bolts and clamping plates.
Final Alignment: Adjust the tracks meticulously to meet alignment requirements. After achieving the desired straightness, tighten all bolts fully.
5. Measurement and Inspection
Post-installation, conduct comprehensive measurements and inspections to verify that the tracks meet the technical quality standards. Document all findings for project records and handover.
Height and Relative Elevation:
Use a leveling instrument to measure the top surface and relative height of the tracks. Ensure they conform to specified tolerances.
Track Gauge Measurement:
Measure the track gauge every 6 meters using a steel tape and spring balance.
The tension applied to the tape should correspond to its span and weight per meter. Since this tension varies, calculate the required force based on the specific tape and gauge used.
To determine the correct force, measure the wheelbase of the crane. For instance, if the wheelbase is 13.5 meters, anchor one end of the tape to a spring balance. Align the zero point of the tape with the center of one wheel. Gradually pull the tape until the 13.5-meter mark aligns with the center of the opposite wheel. Record the force displayed on the spring balance. Use this value as the basis for applying tension when measuring track gauge discrepancies.
Additional Considerations:
Ensure that all materials and tools meet the technical specifications outlined in the project plan.
Regularly calibrate measurement tools to avoid inaccuracies.
Any deviations found during inspections should be corrected immediately to maintain the integrity of the installation.
Document all measurements, alignments, and corrections as part of the final project report.
By following these steps meticulously, the crane tracks can be installed with precision, ensuring safe and efficient crane operation.
