Breaking in a New Wire Rope

Guideline to Inspections and Reports for Equipment. wire Rope and Wire Rope Slings

TM-5-3810-305-10 Crane Wheel Mounted Hydraulic Light 7 1/2 Ton (Rough Terrain Crane) Model LRT 110 Manual
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TM5-3810-305-10 Breaking in a New Wire Rope A new wire rope requires careful installation and close adherence to all the appropriate procedures previously noted. After the rope has been in- stalled and the ends secured in the correct man- ner, the mechanism should be started carefully and then permitted to run through a cycle of operation at very slow speed. During this trial operation, a very close watch should be kept on all working parts - sheaves, drums, rollers - to make certain that the rope runs freely, and without any possible obstructions as it makes its way through the system. If no problems appear in running the rope, the next step should include several run-throughs of the normal operational cycle under light load and at reduced speed. This procedure allows the component parts of the new rope to make a gradual adjustment to the actual operation conditions. Wire Rope and Ope rations Inspection To insure a high level of safety while keeping the annual cost of wire rope at a reasonably low level, it is essential to maintain a well-planned program of periodic inspection. Frequently, there are statutory and/or regulatory agencies whose requirements must be adhered to, but whether or not these exist in a given locale, the wire rope user can be guided by the suggested procedures that follow, Abrasion, bending and crushing represent the ABC’s of wire rope abuse, and it is the primary goal of good inspection practice to discover such conditions early enough so that corrections can be made or ropes replaced safely and with mini- mum effort. When any degradation indicates a loss of original rope strength, a decision must be made quickly as to allowing the rope to remain in service. But such a decision can only be made by an experienced inspector. And this determi- nation will be based on: 1. 2. 3. 4. 5. Details of the equipment’s operation: Will the rope break? Frequency of inspection: Will it be safe until the next scheduled inspection? Maintenance history: How rapid is the degradation? Consequences of failure: Will it present hazards to personnel? Historical records of similar equipment. To make certain that sufficient information is obtained, following are guidelines that should be adhered to: The groove size is evaluated on the basis of how the gage leaf fits the groove. Daylight under the gage is not tolerable when using the worn groove gage. If a full oversize gage is used, some daylight may be acceptable, but this really must be judged by relating the measurement to the actual size of the rope. For new rope, extra caution should be observed as to its fit in the groove. Characteristically, ropes become smaller in diameter immediately after being placed in service. As a result, they would operate satisfactorily in a “worn” groove; one that was gaged OK by the” worn” groove gage. Nonetheless, in some cases, a rope may not “pull down,” and if this happens, abnormal wear may occur. It is important to remember that a tight groove not only pinches and damages the rope, but that the pinching prevents the necessary adjustment of the wires and strands. On the other hand, a groove that is too large will not provide suffi- cient support; in this case, the rope will flatten and thereby restrict the free sliding action of the wires and strands. 4-43

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