Earthmover Wheels and rims are unique in the fact that they are essentially part of a pressure vessel which is being continuously assembled and disassembled. In addition they are subjected to various conditions, extreme loads, chemical reactions, stress and shock through movement.
The failure of rims, wheels and their components has occurred in a variety of areas, for a variety of reasons in a variety of ways. It would be fair to say that most if not all failures may have been prevented if a diligent management system with the relevant procedures were put into place.
Historically the personnel given the responsibility to inspect, assemble and maintain all rims on site has been the resident tyre fitter. Until recently this was a general visual inspection only and was accepted as adequate practice in the industry.
Reasons for Damage and Failure
â€¢ Fatigue â€“ The time the component has been in service is the main factor of fatigue but this can be accelerated by overloading and poor fitting practices. Rims fatigue faster than wheels due to their mounting design
â€¢ Corrosion and Erosion â€“ The strength of components are compromised by rust and wearing of contact surfaces.
â€¢ Incompatible components â€“ The variety of designs make possible the occurrence of non compatible parts being fitted together. A visual inspection cannot be relied upon to ensure compatibility and with the recent introduction of newly developed designs into the market place the need for component identification is essential.
â€¢ Poor Maintenance Practices â€“ Incorrect storage of parts, handling damage, not cleaning parts, use of non genuine parts and the reuse of damaged components can contribute to wheel and rim deterioration.
â€¢ Incorrect Application â€“ Continuous improvement of design due to changing demands on the equipment and industry demands has given a wider choice to the end user. Standard components may be installed where a reinforced or improved design item should have been applied.
â€¢ Poor Management Practices â€“ Insufficient procedures and systems to ensure best practice for fitment, inspection, repair and tracking of rims, wheels and components.
All of the above points can be effectively managed to reduce the occurrence of damage and increase the life of wheels rims and components. Each application requires an evaluation to implement a management system to return best cost per hour return.
Effective Data Collation
The tracking of rims and wheels can be achieved by tailoring a tyre data base to accommodate the requirements to track rims and wheels. Tyre data bases have been designed to effectively measure the performance of different types of tyres on any specific fleet.
The main purpose of a rim and wheel data base is to flag components after a predetermined life to be removed for inspection and to provide a clear history of repairs and inspections as per unit.
Requirements for Effective Rim and Wheel Data Base Implementation
â€¢ Identification markings â€“ Serial numbers to be stamped on all rims and wheels to ensure identification.
â€¢ Inspection period â€“ Determine a time frame as to when components must be inspected.
â€¢ Types of Inspections â€“ On site crack test and/or manufacturers complete test.
â€¢ Data collection â€“ data base and support paper work.
â€¢ Procedures â€“ Systems and procedures to be implemented considering manufacturersâ€™ warranties and guidelines.
The value of a data base will be directly proportional to the quality of data and the frequency of the data entered. The procedures below represent an ultimate scenario.
All rims to be stamped on the gutter section, back section and next to the valve. Number should include number, supplier, date in service and site/client. For example 001-0406-T-BS represents rim number 1, in service at June 2004 supplier is Topy on Blue Sky Mine.
All equipment hours to be entered weekly, every tyre or wheel/rim change and every service. The data base should be able to automatically update All inspections to be recorded whether visual or physical. All component changes to be recorded.
The resources available to the operation will determine the frequency of rim and wheel inspection. The main options for inspection and testing are:
carried out at every opportunity.
Performed by on site personnel who have been made qualified.
Components to be sent to the nearest manufacturersâ€™ or suppliersâ€™ testing premises.
Other options for onsite testing may be available and should be investigated periodically to increase efficiency in the process.
Instructions, systems and paper work required for rim and wheel management to be consolidated with comprehensive procedures covering the areas below.
All procedural steps must work in conjunction with manufacturersâ€™ procedures and recommendations. Allowances and adjustments may be needed to accommodate each specific site.